Riyadh et al .

Riyadh et al. Notes

It gives us a great pleasure to present our effort during our residency years
in summarizing MOST of the ORL-HNS topics from the main textbooks and
references in ORL-HNS. We have done our best in organizing the materials
in each topic to be easy to understand and memorize.

We based our notes mainly on the following references:

Bailey's Head and Neck Surgery, 5 th Ed.
Cummings Otolaryngology 6 th Ed.
Pediatric Airway Surgery, Philippe Monnier.
Head and Neck Surgery, Clinical Reference Guide, Pasha 4 th Ed.
Diseases of ENT, Dhingra 5 th Ed.
Clinics of North America.
nd Ed.

These Notes are not considered as a substitution to the textbooks, as some

of the topics were not covered in these notes. Also, please refer to the above
mentioned references in case of any conflict in the provided information, as
this is a pure human work and amenable to mistakes. We do recommend to
keep adding your own notes to these notes. Moreover, we strongly advise
the final-year residents to read from Manitoba Notes and/or Hart Notes as a
quick review in preparation for the final board exam.

Finally, we would like to thank all of our colleagues, senior registrars,

consultants, and professors who have done a great effort in teaching us
throughout the residency years. Also, we wish you all the best in your
residency training program and your future career.

Regards,

Riyadh et al.1
2016

1 - Bedah, Obaid, Majed, and Feras

1
Contents
1
1 Ear Embryology
14
2 Ear Anatomy
96
3 Physiology of Auditory System
108
4 Audiology and Hearing Assessment
150
5 Approach to Hearing Loss in Adults
179
6 Congenital Hearing Loss
194
7 Congenital Disorders of External Ear
206
8 Disorders of External Ear
241
9 Disorders of Middle ear
487
10 CPA and Petrous Apex Lesions
562
11 Temporal Bone Trauma
580
12 Facial Nerve Paralysis and Rehabilitation
643
13 CSF Otorrhea
654
14 Hearing Rehabilitation
746
15 Physiology of Vestibular System
756
16 Disorders of Vestibular System
847
17 Tinnitus
Riyadh et al. Notes
1
Embryology of Ear

- Prenatal development divided in to separate periods:

1. First period (Pre-embryonic):

- From implantation to end of 3rd week.
- Three layers develop (ectoderm,
mesoderm & endoderm) containing
the notochord.

2. Second period (Embryonic):

- 35 days (until the end of 8th week)
- Major systems and organs are formed, embryo has external shape that
recognizable as human.
- Mesoderm give raise to Pharyngeal arches.
- Ectoderm around the notochord give raise to the Neural crest

3. Fetal period:
- Remaining 7 months
- Change of position and shape of structure

Development of Ear

- Composed of 3 anatomical parts:

1. External ear: (auricle, EAC and tympanic membrane)
2. Middle ear
3. Internal ear

Development of INNER EAR:

- 1st to develop from the 3 parts.

- Starts in 3rd-4th week of fetal life
- Complete by the 16th week.
- By 4th week:
- Thickening of surface Ectoderm (Otic Placode) on
each side of caudal part of hindbrain
(myelencephalon)
- Its form is stimulated by notochord and paraxial
mesoderm
- It invaginates and sinks deep into the underlying
mesenchyme to form (Otic Pit)
- Edges of otic pit comes together to form (Otic
Vesicle or Otocyst) which is considered as
(Primordium of membranous labyrinth)
- Otic vesicle loses its connection with surface
ectoderm.

927
2
Riyadh et al. Notes
3

- A diverticulum grows from the otic vesicle and elongates to form

Endolymphatic duct and sac (1st to develop)

- Otocyst is differentiated into 2 parts:

1. Dorsal Utriclar part:
- Endolymphatic duct, utricle & semicircular ducts)
2. Ventral Saccular part:
- Saccule & cochlear duct

Development of Utricular part of membranous labyrinth takes place

Earlier than Sacular part.

- From the Dorsal utricular part:

- 3 disclike diverticula grows out from the utricular part, the central
parts of these diverticula fuse and disappear (Semicircular Ducts)
- Attached to the utricle, later enclosed in semicircular canals of bony
labyrinth (from mesenchyme around otic vesicle)
- At one end of each semicircular duct a dilatation Ampullae, inside it
differentiate the specialized receptors area (cristae ampullares)
- In the utricle and saccule (maculae)

928
Riyadh et al. Notes
4
- From the ventral saccular part:
- Tubular diverticulam grows (Cochlear duct) and coils to form the
membranous cochlea
- Saccule connected with cochlea by Ductus reuniens (narrowest
segment)
- Organ of corti (Spiral organ) differentiate from cells in the wall of
cochlear duct
- Ganglion cells of the 8th nerve migrate along the coils of membranous
cochlea and form spiral ganglion
- Nerve processes extend from this ganglion to the spiral organ and
terminate on the hair cells
- Periotic Duct: within the cochlear aquaduct, connects the scala
tympani to the posterior cranial fossa

Bony labyrinth:

- Mesenchyme around the otic vesicle condenses

and differentiates into Cartilaginous (Otic
Capsule)
- Transforming growth factor-B1 may play role
- As the membranous labyrinth enlarges, vacuoles
appear in the otic capsule which soon coalesce to
form perilymphatic space
- Membranous labyrinth become suspended in
perilymph

- The perilymphatic space related to cochlea develops two divisions:

1. Scala Vistibuli
2. Scala Tympani

- Cartilaginous otic capsule later ossifies to form the bony labyrinth

(Start ossification at 16 weeks)

929
Riyadh et al. Notes
5
- Variable number of centers that finally fuse without leaving telltale
suture lines. (From periosteal andenchondral ossification)
- The dense bony mass is the Petrous bone

- INNER ear reach Adult SHAPE (NOT SIZE) by the middle of the
fetal period (20-22 weeks)

- Cochlea is developed sufficiently by 20 weeks of gestation and

the fetus can hear in the womb of the mother.

- Channels within the otic capsule includes oval window where part of
the otic capsule becomes the stapes footplate and the annular
ligament, thereby allowing sound from the middle ear to enter the
labyrinthine fluids

930
Riyadh et al. Notes
6
Development of External and Middle ear:

- External and middle ears are independent of the development

of inner ear
- We can see malformed and non-functional inner ear in the
presence of normal external and middle ears, and vice versa.
- External and middle ears mainly derived from 1st and 2nd
Pharyngeal ARCHES.

Development of Middle ear:

- Tubotympanic Recess from the Endoderm of 1st Pharyngeal

POUCH.

1. Proximal part form Eustachian tube

2. Distal part become Tympanic cavity (which envelop the ossicles,

their tendons, ligament and corda typani)

- Late fetal period, expansion of tympanic cavity gives rise to mastoid

antrum (in the petromastoid part of the temporal bone)

- Middle ear reaches Adult SHAPE at Birth.

- No Mastoid air cells present at Birth.

- Mastoid develops from the Squamous and Petrous bones.

- Petrosquamosal suture may persist as a bony plate (Korner’s
septum) separating superficial squamosal cells from the deep
petrosal cells.
- By 2-3 years of age the mastoid cells are well developed and
produce conical projections of the temporal bone (mastoid
process)

931
Riyadh et al. Notes
7

- Ossicles, muscles and nerves in the table above

1. First Branchial Arch

(Meckel’s cartilage):
- Malleus Head and neck
(Mesoderm)
- Anterior Malleal ligament,
- Incus Body and Short process
(Mesoderm)

2. Second Branchial Arch

(Reichert’s cartilage):
- Handle of the Malleus
- Long process and Lenticular
process of the incus
- Stapes (except vestibular part
of footplate and Annular
ligament from Otic capsule)

- Upper parts of ossicles derived from 1st ARCH

- Lower parts of ossicles derived from 2nd ARCH

932
Riyadh et al. Notes
8

933
Riyadh et al. Notes
9
Development of External Ear:

- External acoustic meatus develop from 1st pharyngeal GROOVE

- Ectodermal cells at the bottom of it proliferate to form a solid epithelial

plat (Meatal plug)

- Late in fetal period central part of the plug degenerate forming a

cavity that becomes the internal part of the external acoustic meatus

Degeneration of Plug starts at 7th month from Medial to Lateral

Failure of recannulization results in aural atresia, and may be normal boney

but atresia in cartilage only - Canal cholestetoma

- The meatus short at birth

- EAC reach Adult LENGTH by 9th year

- Tympanic membrane from 1st pharyngeal MEMBRABE which

separate the 1st groove from 1st pouch.

1. Ectoderm of the 1st GROOVE

form Squamous outer layer of
TM (thin skin)

2. Mesoderm from 1st & 2nd ARCH

form collagenic fibers between
the 2 layers.

3. Endoderm of 1st POUCH form

inner mucosal layer (ciliated
columnar)

934
Riyadh et al. Notes
10
Auricle

- Develops from 6 Mesenchymal proliferations in the 1st & 2nd

pharyngeal ARCHES (Auricular hillocks)
- It surrounds the 1st pharyngeal Groove
- Initially, Auricle begin to develop low in the base of the neck
- As the mandible develop it move to its normal position (more lateral
and cranial ).

- Tragus develops from the Tubercle of the 1st ARCH

- Rest of the pinna develops from the remaining 5 Tubercles of the
2nd ARCH.

- Pasha:
1. First Branchial Arch:
- Hillock 1–3:
- 1. Tragus
- 2. Helical crus
- 3. Helix
2. Second Branchial Arch:
- Hillock 4–6:
- 4. Antihelix crus
- 5. Antihelix
- 6. Lobule and antitragus

- Ear lobule is the last to develop

Faulty fusion between 1st and 2nd ARCHs tubercles causes

Preauricular sinus or cyst which is commonly seen between the
tragus and crus of helix.

- By 20th week, Pinna achieves Adult SHAPE

935
Riyadh et al. Notes
11

Temporal bone:

- Derived from 4 separate morphological elements fuse together

1. Tympanic bone.

2. Squamous bone.

3. Petromastoidcomplex

4. Styloid process

936
Riyadh et al. Notes
12
Some Anomalies

Inner ear:

(i) Sheibe's dysplasia.

- Most common inner ear anomaly.
- Cochleosaccular dysplasia.
- Dysplasia is seen in the cochlea and saccule.
- Bony labyrinth is NORMAL.
- Superior part of membranous labyrinth (utricle and semicircular ducts)
is also NORMAL.
- Inherited as an autosomal recessive non-syndromic trait.

(ii) Alexander's dysplasia.

- Affects only the basal turn of membranous cochlea.
- Only high frequencies are affected.
- Residual hearing is present in low frequencies and can be exploited by
amplification with hearing aids.

(iii) Bing-Siebenmann dysplasia.

- Complete absence of membranous labyrinth.

(iv) Michel aplasia.

- Complete absence of bony and membranous labyrinth.
- Petrous apex is absent.
- External and middle ears may be completely unaffected.
- No hearing aids or cochlear implantation can be used.

(v) Mondini's dysplasia.

- Only basal coil is present or cochlea is 1.5 turns.
- Absence of osseous spinal lamina.
- Incomplete partition between the scalae
- Unilateral or bilateral.
- May be seen in Pendred, Waardenburg, Branchio-oto-renal, Treacher-
Collins and Wildervanch syndromes.

(vi) Enlarged vestibular aqueduct.

- Vestibular aqueduct is enlarged (>2 mm)
- Endolymphatic sac is also enlarged and can be seen on T2 MRI.
- Early onset sensorineural hearing loss, which is progressive.
- Vertigo may be present.
- Perilymphatic fistula may occur.

(vii) Semicircular canal malformations.

- Both superior and lateral or only lateral semicircular canal

malformations may be seen.
- They can be identified on imaging techniques

937
Riyadh et al. Notes
13
External ear:

- Auricular appendages (skin tags)

- Low-set slanted ear

- Absence of auricle

- Microtia

- Preauricular sinus

- Atresia of external acoustic meatus

Middle ear:

- Congenital fixation of stapes

938
Riyadh et al. Notes
14
Anatomy of External Ear

- Consists of:

1. Auricle or pinna
2. External acoustic canal
3. Tympanic membrane

1. Auricle or Pinna:
- Projects at a variable angle from the side of the head
- External ear is less than 2-3 cm from the head,
- At an angle of less than 25 degrees from the side of the head.
- Function in collecting sound.
- Lateral surface of the auricle has characteristic prominences and
depressions different in every individual even among identical
twins.
- This unique pattern is comparable to fingerprints.

- The medial (cranial) surface of the auricle has elevations

corresponding to the depressions on the lateral surface, and
possesses corresponding names, for example the eminentia
conchae.
- Post-auricular sulcus is the depression behind the ear next to the
head

939
Riyadh et al. Notes
15
- Auricle is formed from Elastic
fibrocartilage and is a
continuous plate Except for a
narrow gap between the tragus
and the anterior crus of the helix,
where it is replaced by a dense
fibrous tissue band (Incisura
terminalis) which is site for an
endaural incision because it will
not cut through cartilage.

- Lobule lies below the antitragus

and is soft, also composed of
fibrous and adipose tissue (no
cartilage).

- Cartilage of auricle extends about

8 mm down the ear canal to form
its Lateral third of EAC

- Cartilage of the auricle is covered

with perichondrium from which it
derives its supply of nutrients (cartilage itself is avascular).

- Stripping the perichondrium from the cartilage, as occurs following

injuries that cause haematoma, can lead to cartilage necrosis and
formation of Crumpled up 'boxer's ears' cowlflower ear.

- Skin of the pinna is Thin and closely attached to the perichondrium

on the lateral surface

- On the medial (cranial) surface, there is a definite subdermal

adipose layer that allows dissection during pinnaplasty surgery.

- Skin of the auricle is covered with Fine hairs and, most noticeably
in the concha and the scaphoid fossa, there are sebaceous glands
opening into the root canals of these hairs.

- On the tragus and intertragic notch coarse, thick hairs may develop
in the middle-aged and older male.

940
Riyadh et al. Notes
16
- Extrinsic Ligaments of Auricle:
- Connects Cartilage of the auricle Temporal bone.
1. Anterior ligament:
- From the tragus and from a cartilaginous spine on the anterior rim
of the crus of the helix to the root of the zygomatic arch.
2. Posterior ligament:
- From medial surface of the concha to the lateral surface of mastoid
prominence.

- Intrinsic Ligaments of Auricle:

- Connect various parts of the cartilaginous auricle.
- Connects between helix and tragus and another runs from the
antihelix to the posteroinferior portion of the helix.

- Extrinsic Muscles of Auricle:

- 3 muscles radiate out from the auricle to insert into the epicranial
aponeurosis.
- Auricularis anterior, superior and posterior.
- Supplied by Facial nerve CN-VII

941
Riyadh et al. Notes
17
- Intrinsic Muscles of Auricle:
- 6 in number.
- Small, inconsistent and without useful function.

Blood supply for the pinna:

- Branches of External carotid Artery.

1. Posterior auricular Artery:

- The dominant artery.
- Supply:
o Medial surface (except the lobule).
o Concha
o Middle and lower portions of the helix.
o Lower part of the antihelix.

2. Anterior Auricular Artery:

- Branch from Superficial Temporal artery.
- Supply:
o Upper portions of the helix
o Antihelix
o Triangular fossa
o Tragus
o Lobule.

3. Small auricular Artery:

- Branch from Occipital artery.
- Assist the posterior auricular in supplying the medial surface.

- The lymphatic drainage:

- Posterior surface --> Lymph nodes at the mastoid tip
- Tragus and from upper part of the anterior surface to -->
Preauricular nodes
- Rest of auricle --> Upper deep cervical nodes.

942
Riyadh et al. Notes
18
- Nerves supply of auricle:

- Pinna can be source of several graft materials for the surgeon.

- Cartilage from the tragus, perichondrium from the tragus or

concha, and fat from the lobule are frequently used for
reconstructive surgery of the middle ear.

- Conchal cartilage has also been used to correct the depressed nasal
bridge while the composite grafts of the skin and cartilage from the
pinna are sometimes used for repair of defects of nasal ala.

943
19
Riyadh et al. Notes
20
2. External auditory canal

- Extends from Concha of auricle to Tympanic membrane.

- 2.4 cm Long.
- Cartilaginous in Lateral One-third.
- Bony in Medial two-thirds.
- In Adults, it is Not a straight tube.
- Outer part is directed:
- Upwards, backwards and medially
- Inner part is directed:
- Downwards, forwards and medially.

- To examine tympanic membrane, the

pinna has to be Pulled upwards,
backwards and laterally so as to bring the
two parts in alignment.

- In Neonate,
- Tympanic portion of temopral
bone is not yet developed.
- No bony external meatus
- Tympanic membrane is more
horizontally placed.
- Auricle must be gently drawn
downwards and backwards for
the best view of the tympanic
membrane.

- Antero-inferior wall of EAC is slightly longer (31 mm) than Postero-

superior wall (25 mm) because of Antero-inferior inclination of the ear
drum.

944
Riyadh et al. Notes
21
EAC is divided into two parts:
1. Cartilaginous
2. Bony.

Cartilaginous Part:
- Outer 1/3
- 8 mm long.
- Continuation of pinna cartilage .
- Surrounds by incomplete cylinder of cartilage which is deficient in
its superior portion.
- This defect is bridged by dense fibrous tissue that is attached to the
Squamous portion of temporal bone.
- Cartilaginous canal is attached to rim of the bony canal by fibrous
bands.
- Constriction at junction of the cartilage and bony part ( 1st
constriction)

- Fissures of Santorini:
o 2 horizontal fissures located Antero-inferiorly in the
cartilagenous portion.
o Render more flexibility to the external canal.
o Lymphatic channels that connect the lateral cartilaginous
EAC to the parotid and glenoid fossa region
o Allow infections and tumor to pass between the external
canal and the parotid gland.

- Skin covering the cartilaginous canal:

o Thick
o Contains ceruminous and sebaceous glands.
o Contains Hair which is only confined to the outer canal (most
numerous at lateral end of the canal, less numerous medially
and totally absent from the bony cartiagenous junction).
o Furuncles are seen only in outer third.

945
Riyadh et al. Notes
22
Bony Part
- Medial 2/3
- 16 mm long
- Composed of a complete cylinder of bone extending laterally from
the ear drum.
- Narrower than cartilaginous portion and becomes smaller closer to
tympanic membrane.
- Anterior and Inferior walls:
o Tympanic portion of temporal bone.
- Posterior wall:
o Mastoid portion of temporal bone.
- Superior wall:
o Squamous portion of temporal bone.

- Medial end of the bony canal is marked by a groove, tympanic

sulcus, which is absent superiorly.
- Tympanic bone makes up the greater part of the canal, and also
carries the sulcus.

- 2 suture lines in the canal wall:

1. TympanoSquamous:
- Anteriorly
- Transmits Aauricular branch of
Glossopharyngeal nerve
(Jacobson's nerve)

2. TympanoMastoid:
- Posteriorly
- Transmits Auricular branch of
vagus Nerve (Arnold's nerve).
- Evident in the posteriorinferior
portion of the canal wall during
surgical procedures like elevation
of the tympanomeatal flap.

946
Riyadh et al. Notes
23
- Henle's spine:
o Projection produced by temporal bone in Postero-superior
aspect of external auditory canal.
o Important landmark for mastoid surgery

- Isthmus:
o Narrowing in the bony canal.
o 6 mm lateral to tympanic membrane
o 2nd constriction.
o Narrowest part of EAC.

- Anterior recess:
o Recess located in Antero-inferior part of the deep meatus
beyond the isthmus
o Acts as a cesspool for discharge and debris in cases of external
and middle ear infections.

- Condyle of the mandible and glenoid fossa produce a convexity in

Anterior bony canal wall limiting the visualisation of the ear drum.
- This prominence and the Isthmus predispose foreign body
entrapment in Antero-inferior portion of the medial end of the
external canal and are difficult to remove.

- Foramen of Huschke:
o Deficiency in the Antero-inferior part of the bony canal.
o Found in children up to 4 years old or sometimes in adults.
o Connects the bony EAC to parotid and glenoid fossa.
o Permitting infections to and from the parotid)

- Skin covering the bony canal:

o Thin
o Devoid of hair and glands.
o Continuous over the tympanic membrane.

- Skin lining the whole external canal is the only keratinising epithelium
that lacks Eccrine glands.

Relations of External Acoustic Meatus:

• Superiorly: Middle cranial fossa
• Posteriorly: Mastoid air cells and the facial nerve
• Inferiorly: Parotid gland
• Anteriorly: Temporomandibular joint
• Postero-superior part of deeper canal near the tympanic membrane is
related to the mastoid antrum.
("Sagging" of this area may be noticed in acute mastoiditis)

947
Riyadh et al. Notes
24

- Nerve supply to External Auditory Canal:

- Anterior wall and roof:
1. Auriculotemporal (V3) of Trigeminal nerve. (CN-V).
- Posterior wall and floor:
1. Auricular branch of vagus (CN-X) (Arnold's nerve).
2. Facial nerve also supply posterior wall.
o Hitzelberger sign: Numbness at facial nerve area in patient with
acoustic neuroma.

- Blood supply of External Auditory Canal:

- Branches from External carotid Artery:
1. Auricular branch of Superficial Temporal Artery:
o Supply Roof and Anterior portion of the canal.
2. Deep auricular Artery:
o Branch of 1st part of maxillary artery.
o Supply Anterior wall of the canal and outer surface of TM

- Vein drain in the external jagular, maxillary & ptyrygoid plexus

- Lymphatic drainage follows the auricle.

948
Riyadh et al. Notes
25
Physiology:
- Properties of External Auditory canal:
o Lateral growth of the epidermis with the consequence that
layers of keratin are shed towards the surface opening of the
external meatus.
o Rate of migration 0.05 - 0.1 mm/day.
o Same thing for epidermal layer of TM

- Volume of the external canal is about 0.85 ml2.

- Normal flora of the outer ear canal is predominantly Gram-positive

Bacteria: Staphylococcus epidermidis, Staphylococcus aureus,
Diphtheroids (Corynebacterium).

- Glands of External Auditory canal:

1. Ceruminous glands:
o Modified apocrine sweat glands.
o Simple coiled tubular gland
o Open into the root canal of the hair follicles
o Produce a watery, white secretion that slowly
darkens
o Lay deep in the dermis

2. Sebaceous gland
o Simple or branched alveolar glands
o Typical like elsewhere.
o Secrete sebum
o Form their secretion by passive breakdown of cells.

- Wax: Mixture of sebum (from sebaceous glands) + watery secretions

(from ceruminous glands) + Desquamated epithelium.

- Two distinct forms:

1. Dry wax: Yellowish or gray
2. Wet wax: Yellowish brown

- Functions of Wax:
- Wax has acidic PH
- Bacteriostatic properties.
- Contains bactericidal enzymes, amino acids, and immuno globulins
which helps to prevent infection.
- Protecting tympanic membrane.
- Keep moisture of ear canal.
- has a self cleansing action
- Traps the dirt and dust and move it outwards by migration of skin from
the lateral part of tympanic membrane to outside.
- With aging, Cerumen becomes harder, drier, less likely to be cleared
due to atrophy of modified apocrine sweat glands.

949
Riyadh et al. Notes
26
3. Tympanic membrane

- At the medial end of the external auditory meatus.

- Between EAC and middle ear.
- Forms majority of the lateral wall of the tympanic cavity.
- Obliquely set
- Postero-superior part is more lateral than Antero-inferior part (EAC
slightly longer Anteriorly)
- Oval in shape, being broader above than below.
- Forming an angle of about 55° with the floor of the meatus.

- Height 9-10 mm
- Width 8-9 mm
- Thickness 0.1 mm
- Surface Area: 70-80 mm2
- Vibrating surface area: 55 mm2

- Most of the circumference is thickened to form a fibrocartilaginous

ring, the tympanic annulus, which sits in a groove in the tympanic
bone, the tympanic sulcus.

- The sulcus does not extend into the notch of Rivinus at the roof of the
canal, which is formed by part of the squama of the temporal bone.

- From the superior limits of the sulcus, the annulus becomes a fibrous
band which runs centrally as anterior and posterior malleolar folds to
the lateral process of the malleus
- Handle of malleus is clearly visible within the tympanic membrane.

- This leaves a small, triangular region of tympanic membrane above

the malleolar folds within the notch of Rivinus, called the pars
flaccida (Shrapnel's Membrane), which does not have a tympanic
annulus at its margins.

950
Riyadh et al. Notes
27
- Pars Tensa forms the rest of the tympanic membrane and is
concave towards the ear canal.
- Each segment is slightly convex between the lateral attachment of
the annulus and the centre of the membrane where the tip of the
malleus handle is attached at the umbo.

- Both the pars tensa and pars flaccida comprise 3 layers.

1. Outer epithelial layer:
o Epidermis.
o Continuous with the skin of the external meatus.
2. Middle fibrous layer:
o Lamina propria.
o Outer radiating fibrous layer.
o Inner circular fibrous layer.
3. Inner mucosal layer:
o Continuous with the lining of the tympanic cavity)

- In the pars flaccida, the lamina propria is less marked (thin) and
the orientation of the collagen fibers seems random.

Normal TM:
1. Color:
o Pearly grey.
o Shiny.
o Translucent.
o No bulging or retraction.
2. Consistency:
o Smooth.
3. Landmarks:
o Cone-shaped light reflection of the otoscope light
o Short process of mallius
o Handle of mallius
o Umbo
o Anterior and posterior folds

Left TM Right TM

951
Riyadh et al. Notes
28

- Blood supply of the tympanic membrane:

- From branches supplying both the external auditory meatus and

the middle ear.
- Interconnect through extensive anastomoses within the connective
tissue layer of the lamina propria.

1. Epidermal vessels from the Deep auricular branch of the

maxillary artery coming from the external auditory meatus,
2. Mucosal vessels arise from Anterior tympanic branches of the
maxillary artery, stylomastoid branch of the posterior
auricular artery and probably from the middle meningeal
artery.

- Nerve supply of TM:

1. Anterior half of lateral surface:

o Auriculotemporal (V3) of Trigeminal Nerve (CN-V)
2. Posterior half of lateral surface:
o Auricular branch of vagus (CN X) (Arnold's nerve).
3. Medial surface:
o Tympanic branch of CN IX (Jacobson's nerve).

952
Riyadh et al. Notes

Anatomy of Middle Ear 29

- Middle Ear Cleft:
1. Middle ear
2. Eustachian tube
3. Aditus
4. Antrum
5. Mastoid air cells

- Lined by mucous membrane and filled with air within the temporal
bone.
- Extends much beyond the limits of tympanic membrane which
forms its lateral boundary and is sometimes divided into:
1. Epitympanum (Attic):
o Area above the Pars Tensa, Medial to Pars Flaccida and
scutum and lateral to Lateral SCC prominence.
2. Mesotympanum:
o Area opposite to Pars Tensa.
3. Hypotympanum:
o Area below the level of Pars Tensa.
4. Protympanum:
o Area around the tympanic orifice of the Eustachian tube.

953
Riyadh et al. Notes

- Middle ear can be likened to a30

Six-sided Box with a Roof, Floor, Medial, Lateral,
Anterior and Posterior walls

Roof
- Thin plate of bone called Tegmen Tympani.
- Separates tympanic cavity from the dura of Middle cranial fossa.
- Extends posteriorly to form the Roof of the Aditus and Antrum.
- Formed from both Petrous and Squamous portions of temporal bone with
suture line in between known as petrosquamous suture line.
- PetroSquamous suture line:
o Unossified in the young and close in adult life.
o Provide a route of access for infection into the extradural space in
children .
o Veins from the tympanic cavity pass through this suture line to the
Superior Petrosal Sinus.

954
Riyadh et al. Notes

31

Floor
- Thin plate of bone.
- Narrower than the roof of the middle ear cavity
- Separates tympanic cavity from the jugular bulb.
- Its thickness can vary according to the height of the jugular fossa.
- Sometimes, it is congenitally deficient and the jugular bulb may then project
into the middle ear; separated from the cavity only by fibrous tissue & mucosa.
- Tympanic Canaliculus:
o Small opening at junction of Floor and Medial wall of the cavity
o Allows the entry of Tympanic branch of the Glossopharyngeal nerve
"Jacobson’s Nerve" into the middle ear from its origin below the base of
the skull.

Anterior wall
o The narrowest wall because Medial and lateral walls converge anteriorly.
o 5 openings perforates the Anterior wall.
o Lower 1/3 of Anterior wall:
- Thin plate of bone covering Internal Carotid artery as it enters the skull and
before it turns Anteriorly.
- Perforated by 3 openings:
1. Superior and Inferior Caroticotympanic nerves carrying sympathetic fibers
to the tympanic plexus.
2. Tympanic branches of internal carotid artery.

o Middle 1/3 of Anterior wall:

- Perforated by 2 openings:
1. Upper opening for the Canal of Tensor Tympani Muscle that subsequently
runs along the medial wall of the tympanic cavity.
2. Lower one for the Eustachian tube (oval and 5 x 2 mm in size)

o Upper 1/3 of Anterior wall:

- Pneumatized and may house the Anterior Epitympanic sinus.
- Epitympanic recess:
o Small niche anterior to ossicular heads
o Can hide residual cholesteatoma in canal wall up surgery.

955
Riyadh et al. Notes

32

Posterior Wall:
- Lies close to the mastoid air cells.
- Aditus:
o Opening through which
Attic communicates with
the antrum.
o Lies above the pyramid,
near the junction with the
Roof of the middle ear.
- Fossa Incudis:
o Small depression below
the Aditus.
o Houses:
1. Short process of Incus
2. Short Incudal ligament.
- Pyramid:
o Bony projection from the posterior wall with its apex pointing
Anteriorly.
o Below Fossa incudis.
o Contains Tendon of Stapedius muscle to get attachment to the
Neck of and Posterior crus of Stapes.

956
Riyadh et al. Notes

33

- Facial Nerve: Runs in the posterior wall just behind the pyramid.
- Facial Recess:
o Also called posterior sinus (supra pyramidal recess)
o Depression in the posterior wall Lateral to Pyramid.
o Bounded Medially by Vertical part of Facial nerve (CN-VII)
o Bounded Laterally by Chorda tympani and tympanic annulus.
o Bounded from Above by Fossa incudis.
o Surgically, facial recess is important, as direct access to the
mesotympanum can be made through this into the middle ear
without disturbing posterior canal wall (canal wall up or "intact canal
wall technique").

- Facial canal: Passes Supero-inferiorly immediately posterior to the

middle ear until it terminates at the stylomastoid foramen.
- Posterior cranial fossa and sigmoid sinus located posterior to the
posterior wall

957
Riyadh et al. Notes

34

Medial wall
- Separates the tympanic cavity from the
internal ear.
- Promontory:
o Most prominent portion in the medial
surface due to the basal coil of
cochlea
o Has small grooves on its surface
containing the nerves which form
Tympanic plexus.
o Sometimes the groove containing the
tympanic branch of the
Glossopharyngeal nerve "Jacobson’s
Nerve" may be covered by bone "small canal".

- Oval window:
o Also called Fenestra vestibuli.
o Located Posterior and Superior to the promontory.
o Connects tympanic cavity with vestibule
o Closed by foot plate of stapes and its surrounding annular ligament.
o Its size naturally varies with the size of the footplate, but on average it is
3.25 mm long and 1.75 mm wide.
o The long axis of the fenestra vestibuli is Horizontal.
o Lies at the bottom of a depression or niche known as fossula that can be of
varying width depending on the position of the facial nerve superiorly, and
the prominence of the promontory inferiorly.

958
Riyadh et al. Notes

35

- Round window:
- Also called Fenestra cochlea.
- Lies Inferior and posterior to oval window niche.
- Round window niche is most commonly Triangular in shape, with Anterior,
Posterosuperior and Posteroinferior walls.
- Posterosuperior and posteroinferior walls meet posteriorly leading on to sinus
tympani.
- Subiculum is Posterior extension of promontory separating oval and round
windows.
- Covered by the secondary tympanic membrane.
o Membrane is usually out of sight, obscured by the overhanging edge of the
promontory forming the niche and mucosal folds within it.
o Roughly oval in shape, about 2.3 x 1.9 mm in dimension.
o Made up of Three layers: Outer mucosal, Middle fibrous and Inner
endothelial layer.
o Does not lie at the end of Scala tympani but forms part of its floor.
o It tends to curve towards the Scala tympani of the basal coil of the cochlea,
so that it is concave when viewed from the middle ear.
o Ampulla of Posterior SCC is the closest vestibular structure to this
membrane.
o Nerve supplying Ampulla of Posterior SCC (Singular nerve) runs 1 mm
behind and parallel to the posterior portion of the membrane
o It is a landmark for the position of the singular nerve during surgical
procedures like singular neurectomy for treatment of intractable BPPV.

959
Riyadh et al. Notes

- Facial nerve Canal: 36

- Also called Fallopian canal.
- Runs Above promontory and oval window in an Antero-posterior direction.
- Behind the oval window, the facial canal starts to turn inferiorly as it begins its
descent in the Posterior wall of the tympanic cavity
- Its bony covering may sometimes be congenitally dehiscent and the nerve may
lie exposed making it very vulnerable to injuries or infection.
- Facial nerve canal is marked Anteriorly by Processus Cochleariformis
- It has a smooth rounded lateral surface that often has Microdehiscences and
when the bone is thin or the nerve exposed by disease, there are two or three
straight blood vessels clearly visible along this line of nerve. These are the only
straight blood vessels in the middle ear and indicate quite clearly that the facial
nerve is very close.

- Prominence of Lateral SCC:

- Above facial nerve canal.
- Forms Medial wall of the
Epitympanum.
- Major feature of the Posterior
portion of the Epitympanum, lying
posterior and extending a little
lateral to the facial canal.
- During a cortical mastoidectomy,
the Triangular relationship of
Lateral SCC, Short process of
incus and Facial nerve is often
quite helpful.

- In well aerated mastoid bones,

labyrinthine bone over Superior
SCC may be prominent, running at right angles to the lateral canal and joining
it anteriorly at a swelling which houses the ampullae of the two canals.

- Processus Cochleariformis:
- Hook-like projection just Anterior to the oval window.
- Tendon of Tensor Tympani takes a turn here to get attachment to the Neck of
malleus.
- Cochleariform process also marks the level of the Geniculate ganglion of Facial
nerve which is an important landmark for surgery of the facial nerve.

- Cog Process:
- Small bony bar Anterior and
Superior to Cochleariform
process which separates
Anterior Epitympanum from
rest of the attic.
- Facial Nerve runs between
Cog process & cochleariform
process.
- Geniculate ganglion lies deep
and medial to cog.

960
Riyadh et al. Notes

- Sinus Tympani (Infra Pyramidal37 Recess):

- Most constant depression present in Retrotympanic area.
- Posterior extension of mesotympanum and lies deep to both the promontory
and the pyramid "facial nerve"
- Lies Medial to pyramid "facial nerve" .
- Bounded by the:-
o Subiculum Below.
o Ponticulus Above. "Arise from promontory above subiculum and runs to the
pyramid on the posterior wall of the cavity"

- Occasions it can communicate with the mastoid air cells..

- The sinus can extend as far as 9 mm into the mastoid bone when measured
from the tip of the pyramid.
- Its importance is that cholesteatoma (which has extended here from
mesotympanum) can hide to which access is difficult.
- Most Inaccessible site in the middle ear and mastoid.

Lateral Wall:
- Separates middle ear from the external ear.
- Formed mainly by tympanic membrane, partly by the ring of bone into
which this membrane is inserted.
- This ring of bone is incomplete at its upper part, forming a notch (notch of
Rivinus), close to which are Three small openings.
- Centrally: Formed largely by Tympanic membrane, with the malleus
attached to the membrane at the umbo
- Superiorly: Formed by Scutum "outer attic wall" bony lateral wall of
Epitympanum
- Inferiorly: form by bony lateral wall of the Hypotympanum

961
Riyadh et al. Notes

- Tympanic membrane: 38
Semitransparent and
forms a 'window' into
the middle ear.
- It is possible to see
some structures of the
middle ear through the
normal tympanic
membrane (Long
process of Incus,
incudostapedial joint and
the round window).

- Chorda Tympani nerve:

o Enters the middle ear through Posterior Canaliculus.
o Runs on the medial surface of the tympanic membrane between the handle
of malleus and long process of incus, Above the attachment of tendon of
tensor tympani.
o Lies along the tympanic membrane and malleus until exiting through the
Anterior Canaliculus.

- Scutum:
o Thin bone portion and easily eroded by cholesteatoma, leaving a telltale
sign on a high resolution Coronal CT scan.

- Three openings present in medial surface of lateral wall of tympanic cavity:

1. Posterior Canaliculus:
o Situated at junction of Lateral and Posterior walls of the tympanic cavity
immediately behind the tympanic membrane.
o Present at the level of Upper end of the handle of the malleus.
o Leads to bony canal which descends through the posterior wall of the
tympanic cavity in front of the facial nerve canal.
o The canal ends in facial nerve canal near the Stylomastoid foramen.
o Also known as canal for chorda tympani nerve.
1. Chorda tympani nerve Enters the tympanic cavity through this opening.
2. Transmits Stylomastoid artery which usually accompanies the chorda
tympani nerve.

2. PetroTympanic (Glaserian) Fissure:

o A small slit about 2 mm long which opens Anteriorly just above the
attachment of the tympanic membrane.
1. Houses Anterior Process of Malleus
2. Receives the Anterior malleolar ligament.
3. Transmits Anterior tympanic branch of maxillary artery to Tympani cavity.
4. If the Anterior Canaliculus is inconsistent, Chorda Tympani Nerve leaves
through this fissure.

3. Canal of Hugier (Anterior canaliculus):

o Lies medial to PetroTympanic (Glaserian) Fissure.
o Chorda tympani nerve Leaves the tympanic cavity through this.

962
Riyadh et al. Notes

39

963
Riyadh et al. Notes

40

964
Riyadh et al. Notes

- Mastoid Antrum 41
- Large, air-containing space in the
upper part of mastoid (Petrous part of
the temporal bone).
- Communicates with the attic through
the aditus.
- Roof is formed by the Tegmen Antri
which is a continuation of the Tegmen
Tympani and separates it from the
Middle cranial fossa.
- Antrum (NOT the air cells) is well developed at birth.
- By adult life Antrum has a volume of 2 mL.
- Medial wall relates to Posterior SCC.
- Lateral wall is formed by a plate of bone
which is on an average 1.5 cm thick in the
adult.
- This bone is marked externally on the
surface of mastoid by Suprameatal
(MacEwen's) Triangle:

o Important landmark to locate the

mastoid in mastoid surgery.
o Located Postero-Superior to
External auditory meatus.

- Suprameatal (MacEwen's) triangle boundaries:

1. Superiorly by: Supramastoid crest (Temporal line)
2. Anteriorly by: Postero-Superior margin of External auditory meatus.
(spine of henle)
3. Posteriorly by: Vertical tangent to the posterior margin of meatus.

965
Riyadh et al. Notes

42

- Aditus:
- Opening through which the attic communicates with the antrum.
- Lies between:
o Medially: The bony prominence of the horizontal SCC
o Laterally: Fossa Incudis to which is attached the short process
of incus.
- Facial nerve courses just below the aditus.

- Mastoid and Its Air Cell System:

- Mastoid consists of bone cortex with a "honeycomb" of air cells
underneath.
- Acting as a reservoir of air to limit pressure changes within the
middle ear.
- Facial nerve is embedded in bone in its Petrous part but exits at the
stylomastoid Foramen.
- In infants, Mastoid process is undeveloped and the Facial nerve is
very superficial.
- Mastoid process starts to develop at age of 1 year.
- Complete development at age of 2 years.
- Lining of the mastoid is a Flattened, Non-ciliated epithelium without
goblet cells or mucus glands.

966
Riyadh et al. Notes

- Depending on development of43 air cell, three types of mastoid have

been described :-
1. Well-Pneumatised:
o Cellular.
o Mastoid cells are well developed and intervening septa are thin.
2. Diploetic:
o Mastoid consists of marrow spaces and a few air cells.
3. Sclerotic:
o Acellular
o No air cells or marrow spaces.
o Occurs in 20 % of adult temporal bones.
o Seen in individuals with Chronic ear disease.
o Mastoid antrum may be the only air-filled space in the mastoid
mastoids & antrum is usually small and the sigmoid sinus is
anteposed.

™ With any type of mastoid pneumatisation, Antrum is always

present.

- Depending on the location, mastoid air cells are divided into:

1. Zygomatic cells (in the root of zygoma).
2. Tegmen cells (extending into the tegmen tympani).
3. Perisinus cells (overlying the sinus plate).
4. Retrofacial cells (round the facial nerve).
5. Perilabyrinthine cells (located above, below and behind the
labyrinth, some of them pass through the arch of superior semicircular
canal. These cells may communicate with the petrous apex).
6. Peritubal (around the eustachian tube. Along with hypotympanic cells
they also communicate with the petrous apex).
7. tip cells which are quite large and lie medial and lateral to the
digastric ridge in the tip of mastoid.
8. Marginal cells (lying behind the sinus plate and may extend into the
occipital bone).
9. Squamosal cells (lying in the squamous part of temporal bones).

- Abscesses may form in relation to these air cells and may sometimes
be located far from the mastoid region.

967
Riyadh et al. Notes

- Development of Mastoid 44
- Mastoid develops from Squamous and Petrous bones.
- Petrosquamosal suture may persist as a bony plate (Korner's
septum) separating superficial squamosal cells from the deep
petrosal cells.
- Korner's septum is surgically important as it may cause difficulty in
locating Antrum and the deeper cells; and thus may lead to
incomplete removal of disease at Mastoidectomy .
- Mastoid Antrum cannot be reached unless the Korner's septum has
been removed.

- Posterior to mastoid is the Sigmoid sinus.

- It curves downwards only to turn sharply upwards to Pass medial to
Facial nerve and then becomes the dome of the jugular bulb in the
middle ear space.
- The posterior belly of the digastric muscle forms a groove in the
base of the mastoid bone.

968
Riyadh et al. Notes

45

969
Riyadh et al. Notes

Temporal Bone Dissection LATERAL 46 APPROACH

http://drfling.hyperphp.com/Notes/Temporal_Bone_Dissection_Lateral%2
0Approach.htm

970
Riyadh et al. Notes

47

971
Riyadh et al. Notes

48

972
Riyadh et al. Notes

- Contents of Tympanic cavity: 49

- Most important content of the middle ear is AIR which flows into the
middle ear through a patent Eustachean tube.
- 3 Ossicles: (malleus - Incus - Stapes)
- 2 muscles: (Tensor Tympani - Stapedius)
- 2 Nerves: (Chorda tympani - Tympanic plexus).

- Ossicles:
- Three ossicles: Malleus (Hammer)- Incus (Anvil) - Stapes (Stirrup)
- Form a semi-rigid bony chain for conducting sound.
- Held in position by Ligaments, Muscles and Interossicular joints.
- Malleus is most Latero-Inferior and attached to TM.
- Incus is most Latero-Superior.
- Stapes is most medial and attached to the oval window.

- Malleus:
- Largest ossicle
- Measuring up to 9 mm length
- Shape look like a Hammer
- Has Head, Neck and 3 processes (Handle,
Lateral and Anterior Process) arising from
below the neck.
x Head of malleus:
- Lie in the Attic "Epitympanum".
- Divides Attic into anterior and posterior
portion.
- During surgical procedures for attic
cholesteatoma clipping of this head will
improve the exposure in the attic region.
- Supported by superior ligament, which runs upward to Tegmen
tympani.
- Has a saddle-shaped facet on its Postero-Medial surface to articulate
with the Body of the incus by synovial joint.

973
Riyadh et al. Notes

- Cog: 50
o Projection in Lower part of Head of Mallues.
o NOT eroded by cholestelema and can be used as surgical landmark
in mastoid surgery if handle of malleus is eroded by cholestelema.

x Neck of malleus:
- Also lie in the attic "Epitympanum".
- Below the neck the bone broadens and gives rise to Handle, Lateral
and Anterior Process.

x Handle of malleus (Manubrium):

- Runs downwards, Medially and slightly backwards between the
mucosal and fibrous layers of the tympanic membrane.
- Medial surface of handle, near its upper end, is a small projection into
which the tendon of the Tensor tympani muscle inserts.
- Its most prominent lower part is Umbo.

x Lateral process of malleus:

- Forms a knob-like projection on outer surface of tympanic membrane.
- Gives attachment to Anterior and posterior malleal (malleolar) folds
from the tympanic annulus.

x Anterior process of malleus:

- A slender Anterior ligament arises from anterior process to insert into
the petrotympanic fissure

- Chorda tympani nerve crosses the upper part of Malleus Handle on its
medial surface Above the insertion of Tendon of tensor tympani, but
below the neck of the malleus itself.
- Neck of the malleus connects the Handle with the head and
Amputation of the head by cutting through the neck leaves both
chorda tympani and tensor tympani intact.

974
Riyadh et al. Notes

51

- Incus:
- has a body and 2 process
(Short and Long process)
- Shape look like Anvil.
- Body and Short process lie in
the Attic.
x Body of Incus:
- Has a cartilage-covered facet
corresponding to that on the
malleus.
- Body is suspended by the
Superior Incudal Ligament
that is attached to the
tegmen tympani.

x Short Process of Incus:

- Projects backwards from the body to Lie in the
Fossa incudis to which it is attached by a Short
suspensory ligament

x Long Process of Incus:

- Hangs vertically and descends into the
Mesotympanum behind and medial to the handle
of the malleus
- At its tip, there is a small medially directed
called Lenticular process attaches to the head of stapes.
- Long process of the incus has poor blood suppy and prone for
undergoing necrosis in disease conditions.
- 1st part to be eroded in cholesteatoma.

x Lenticular process of Incus:

- Sometimes been called the fourth ossicle because of its incomplete
fusion with the tip of Long processof incus, giving the appearance of
a separate bone or at least a sesamoid bone.

975
Riyadh et al. Notes

52
- Stapes:
- Has a head, neck, Anterior and
Posterior crura (Limb) And a
Footplate (Base)
- Footplate is held in oval window
by Annular ligament.
- Shape look like Stirrup.

x Head of Stapes:
- Points laterally and has a small cartilage-
covered depression for a synovial articulation
with the Lenticular process of the Incus

x Neck of Stapes:
- Stapedius tendon inserts into Posterior part of Neck and Upper
portion of Posterior crus.

x Crura of Stapes:
- Neck of the stapes gives rise to two crura.
- There is great variation in the shape of the two crura.
- Posterior crus is Longer than Anterior crus.
- Anterior crus is thinner and less curved than Posterior crus.
- The two crura join the footplate.

x Footplate of Stapes:
- Has a convex superior margin, and almost straight inferior margin
and curved anterior and posterior ends.
- Average dimensions of the footplate 3 mm long and 1.4 mm wide
- It lies in the oval window where it is attached to the bony margins
by the Annular ligament.
- Long axis of the footplate is almost horizontal, with the posterior
end being slightly lower than the anterior.

- Ossicular joints are synovial type.

- Malleo-incudal joint: Saddle joint
- Incudo-stapedial joint: Ball and socket joint.

976
Riyadh et al. Notes

- Intratympanic Muscles: 53
- 2 muscles: (Tensor tympani and Stapedius)

- Tensor Tympani Muscle:

- 1st Arch Muscle.
- Supplied by Medial Pterygoid Nerve which is branch of Mandibular
nerve (V3) (Trigeminal Nerve)
- It is a long slender muscle arising from the walls of the bony canal
lying above the Eustachian tube.
- Parts of the muscle also arise from the Cartilaginous portion of the
Eustachian tube and Greater wing of the sphenoid.
- Then it passes backwards into the tympanic cavity lying on the
medial wall of the middle ear just below the level of the facial
nerve.
- The bony covering of the canal is often deficient in its tympanic
segment where the muscle is replace by its tendon.
- This tendon enters the Processus cochleariformis on the medial
wall, where it is held down by a transverse tendon as it turns
through a right angle to pass laterally and insert into the Medial
Aspect of Upper end of the Malleus Handle.
- It tenses the tympanic membrane by holding the handle of the
malleus thus helping the middle ear in better sound perception.

- Stapedius Muscle:
- 2nd arch muscle.
- Supplied by a branch of Facial nerve (CN-VII).
- Smallest muscle in the body.
- Arises from walls of the concial cavity within the pyramid.
- A slender tendon emerges from the apex of the pyramid and inserts
into the Neck and Posterior crus of stapes.
- On contraction, this muscle rocks the stapes backwards holding it
firm against the annular ligament preventing excessive
transmission of sound into the inner ear.
- Protective role by dampen very loud sounds.
- Preventing noise trauma to the inner ear.
- Patients with facial nerve palsy have hyperacusis because of lack of
action of this muscle.

977
Riyadh et al. Notes

- Tympanic Plexus: 54
- Lies on the promontory.
- Formed by:
1. Tympanic branch of Glossopharyngeal nerve . (Jacobson's nerve)
2. Caroticotympanic nerves (sympathetic fibers from the plexus
around the internal carotid artery).

- Tympanic plexus gives innervations to:

1. Medial surface of TM.
2. Mucous membrane lining the tympanic cavity, Bony Eustachean
tube, Mastoid Antrum and its air cells.
3. Secretomotor fibers to Parotid gland.

- Tympanic plexus provide the following branches:

1. Branches to the mucous membrane lining the tympanic cavity,
eustachean tube, mastoid antrum and its air cells
2. A Deep branch joining the Greater superficial petrosal nerve.
3. Lesser superficial petrosal nerve, which contain all the
parasympathetic fibers of Glossopharyngeal nerve (CN-IX) to
supply the parotid gland.

o Lesser superficial petrosal nerve leaves the middle ear through a

small canal below the tensor tympani muscle where it receives
parasympathetic fibers from Facial nerve (CN-VII) nerve by way
of a branch from the geniculate ganglion.
o The full nerve passes through the temporal bone to emerge
lateral to the greater superficial petrosal nerve on the floor of
the middle cranial fossa, outside the dura.
o It then passes through the foramen ovale with the Mandibular
nerve and Accessory meningeal artery to the otic ganglion.
o Post ganglionic fibers from the otic ganglion supply secretomotor
fibers to the parotid gland by way of the auriculotemporal nerve.

- Course of secretomotor fibers to the parotid:

- Inferior salivary nucleus → CN IX → Tympanic branch → Tympanic
plexus → Lesser petrosal nerve → Otic ganglion →
Auriculotemporal nerve → Parotid gland.

o Section of Tympanic branch of glossopharyngeal nerve (Jacobson's

nerve) can be carried out in the middle ear in cases of Frey's
syndrome.
o Frey's syndrome are redness and sweating on the cheek area adjacent to
the ear appear when the affected person eats as a side effect of parotid
gland surgery or due to injury to Auricotemporal nerve.
o Auriculotemporal branch of the Trigeminal nerve carries sympathetic
fibers to the sweat glands of the scalp and parasympathetic fibers to the
parotid gland.
o As a result of severance and inappropriate regeneration, the
parasympathetic nerve fibers may switch course, resulting in sweating in
the anticipation of eating, instead of the normal salivatory response.

978
Riyadh et al. Notes

55

979
Riyadh et al. Notes

- Chorda Tympani Nerve: 56

- Branch of Facial nerve (CN-VII)
- Enters the middle ear through Posterior canaliculus, at the junction
of Lateral and posterior walls.
- Runs on the medial surface of the tympanic membrane between the
Handle of malleus and Long process of Incus, above the attachment
of tendon of tensor tympani.
- Continue forwards and leave by way of the Canal of Hugier
(Anterior canaliculus), which subsequently joins the Petrotympanic
fissure.
- Carries Taste from Anterior 2/3 of tongue.
- Supplies Secretomotor fibers to Submaxillary and Sublingual
Salivary glands.

- Lining of Middle Ear Cleft:

- Mucous membrane of the Nasopharynx is continuous with that of
Middle ear, Aditus, Antrum and Mastoid air cells.
- Histologically, Epithelium of middle ear cavity is varies according to
the location.

- Eustachian Tube Lining:

- Pseudostratified Ciliated Columnar Epithelium
- With several mucous glands in the submucosa.
- At its nasopharyngeal end, the mucosa is truly respiratory; but in
passing along the tube towards the middle ear, the number of
goblet cells and glands decreases, and the ciliary carpet becomes
less profuse.

980
Riyadh et al. Notes

- Tympanic cavity Lining: 57

- Antero-Inferior Compartment (Hypotympanum):
o Pseudostratified Ciliated Columnar Epithelium.
o The function of this compartment is devoted primarily to
mucociliary clearance.
- Middle Compartment:
o Cilliated Cuboidal Epithleium.
- Postero-Superior compartment (Epitympanum and Mastoid):
o Flat Non-ciliated Epithelium.
o A gas exchange occurs in this compartment.

- Mucous membrane wraps the

middle ear structures (ossicles,
muscles, ligaments, and nerves)
like peritoneum wraps various
viscera in the abdomen, Raising
several folds and dividing the
middle ear into various
compartments.

- As a result, Only route for

ventilation of Epitympanic
space from Mesotympanum is
via 2 small openings between the
various mucosal folds:
1. Anterior isthmus tympani.
2. Posterior isthmus tympani.

- Prussak's Space: = Superior recess of the tympanic membrane

- Bordered by:
- Laterally: Pars Flaccida, Laterally
- Medially: Neck of the Malleus.
- Inferiorly: Lateral process of Malleus
- Superiorly: Lateral malleolar fold.

- This space can play an important role

in the retention of keratin and
subsequent development of
cholesteatoma. ( 1st site of origin of
cholesteatoma.)

- The mucosal folds have been described in detail by Figure

below

981
Riyadh et al. Notes

58

982
Riyadh et al. Notes

- Blood Supply of Middle Ear59

- Middle ear is supplied by 6 Arteries.
- From both Internal and External carotid system.
o 2 Main Arteries:
1. Anterior tympanic branch of Maxillary Artery:
o Supplies Tympanic membrane.
2. Posterior tympanic branch of Stylomastoid Artery:
o Branch of Posterior Auricular Artery.
o Supplies Middle ear and mastoid air cells.

o 4 Minor Arteries:
1. Petrosal branch of Middle Meningeal Artery:
o Runs along Greater Petrosal Nerve.
2. Superior tympanic branch of Middle Meningeal Artery:
o Traversing along the canal for tensor tympani muscle.
3. Branch of Artery of Pterygoid Canal:
o Runs along Eustachian tube.
4. Tympanic branch of internal carotid.

- Veins drain into:

1. Pterygoid venous plexus
2. Superior Petrosal sinus

- Lymphatic Drainage of Ear

- Lymphatics from the middle ear drain into retropharyngeal and
parotid nodes.
- Lymphatics of the Eustachian tube drain into Retropharyngeal group

983
Riyadh et al. Notes
60

Inner Ear:

- Also called the internal ear or the labyrinth.

- Important organ of hearing and balance.

- Consists of:
1. Bony labyrinth.
2. Membranous labyrinth.

Bony Labyrinth:

- Located in the petrous portion of the temporal bone.

- Surrounds the membranous labyrinth and contains Perilymph.
- Consists of:
1. Cochlea
2. Vestibule.
3. Semicircular canals.

Otic capsule or the bony labyrinth ossifies from 14 centres, the first one appears in the
region of cochlea at 16 weeks and the last one appears in the posterolateral part of
posterior semicircular canal at 20th week.

984
Riyadh et al. Notes
61
1. Cochlea:
- Anterior portion of the bony labyrinth
- Contains the cochlear duct of the membranous labyrinth.
- Coiled tube making 2.5 - 2.75 turns round a central pyramid of
bone called the modiolus.
- Base of modiolus is directed towards internal acoustic meatus and
carries branches of the cochlear nerve to the cochlear duct.
- Around the modiolus and winding spirally like the thread of a
screw, is a thin plate of bone called osseous spiral lamina.
- It divides the bony cochlea incompletely, and gives attachment to
the basilar membrane.
- Spiral ganglion: contains cell bodies of the cochlear nerve,
located within the central modilous in lateral end of cochlear nerve.
- The promontory (bony bulge in the medial wall of middle ear) is
due to the basal coil of the cochlea.

- The bony cochlea contains three compartments:

1. Scala Vestibuli.
2. Scala Media.
3. Scala Tympani.

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Riyadh et al. Notes
62
- Scala Vestibuli
o Filled with Perilymph.
o Begins in vestibule.
o Closed by the footplate of stapes over the oval window which
separates it from the air-filled middle ear.
o Communicate with Scala tympani at the apex of cochlea
through an opening called helicotrema.

- Scala Media
o Also called Cochlear duct,
Membranous cochlea
o Filled with Endolymph.
o Begins at round window

- Scala Tympani
o Filled with Perilymph.
o Closed by secondary
tympanic membrane.
o Connected with the
subarachnoid space through the aqueduct of cochlea.

- Cochlear aqueduct contains the periotic duct, allows perilymph

to drain into CSF (Subarachnoid space), ends in posterior cranial
fossa.

2. Vestibule:
- Middle portion of the bony labyrinth.
- Oval window lies in its lateral wall.
- Inside of its medial wall presents two recesses:
1. Spherical recess: lodges the Saccule (Anterior)
2. Elliptical recess: lodges the Utricle (Posterior)

- In the posterosuperior part of vestibule are the five openings of

semicircular canals.
- Vestibular Aqueduct contains the endolymphatic duct and runs
from the vestibule to the posterior surface of the petrous pyramid
in the posterior cranial fossa (opening is the operculum)

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Riyadh et al. Notes
63
3. Semicircular Canals (SCC):
- Posterior portion of the bony labyrinth.
- Three in number, Lateral, Posterior and Superior.
- Lie in planes at right angles to one another.
- Each canal has an Ampullated end which opens independently into
the Utricle and a Nonampullated end.
- Cupula: gelatinous layer located within each ampulla, extends to
the roof of the ampulla sealing the SCC.
- Cilia are embedded in the cupula; deflects of the cupula bends
stereocilia.
- Membranous labyrinth turns with head, endolymph stays but due to
inertial mass; causes pressure across cupula
- The three canals open into the vestibule by five openings.
- Lateral (Horizontal) SCC:
o Inclined 30 degrees from horizontal.
o AmpulloPetal flow of endolymph (TOWARD vestibule)
Increase vestibular neuron firing rate (Excitatory).
- Superior (Anterior) and Posterior SCC:
o Vertical canals.
o Share one nonampullated ends Crus commune.
o AmpulloFugal flow of endolymph (AWAY from vestibule)
Increase vestibular neuron firing rate (Excitatory).

Membranous Labyrinth:

- Located within the bony labyrinth and contains Endolymph

- consists of:
1. Cochlear duct
2. Saccule
3. Utricle
4. Three semicircular ducts
5. Endolymphatic duct and sac.

1. Cochlear duct
- Also called membranous cochlea or the scala media.
- Blind coiled tube located within the bony cochlea.

987
Riyadh et al. Notes
64

- Triangular on cross-section and its three walls are formed by:

1. Basilar membrane:
o Floor of scala media.
o Between scala media and scala tympani.
o Supports the organ of corti.
o Base: Stiffer and Thinner.
o High frequencies of sound are heard at the Basal coil.
o Apex: Flexible and Thicker.
o Lower frequencies are heard at the Apical coil.
2. Reissner's membrane:
o Also called vestibular membrane.
o Roof of scala media.
o Separates scala media from the scala vestibuli.
o Two-cell layer membrane separated by a basement membrane:
o Endothelial cell layer facing the scala media.
o Mesothelial cell layer facing the scala vestibuli.

3. Stria vascularis:
o Lateral wall of scala media.
o Contains vascular epithelium.
o Support cochlear function.
o Na-K ATPase keeps membrane potential at +80 mV.
o Secrets of Endolymph.

- Ductus reuniens: narrowest segment connects cochlear duct to the

saccule.
- Periotic duct: located within the cochlear aqueduct, connects the
scala tympani to the posterior cranial fossa.

988
Riyadh et al. Notes
65

- The central bony axis of the spiral, the modiolus (mod) contains the
spiral ganglion (sg) comprised of bipolar neurones that peripherally
innervate the hair cells and centrally form the cochlear nerve (co nv).
- Afferent fibres representative of low (blue), middle (green) and high
(red) frequency illustrate the tonotopic arrangement within the nerve.

2. Saccule
- Lies in the Anterior part bony vestibule.
- Anterior and perpendicular to the utricle and opposite the stapes
footplate.
- Communicates with Cochlear duct (via Ductus reuniens).
- Communicates with Endolymphatic duct (via Saccular duct).
- Does NOT communicate directly with utricle
- Its sensory epithelium is called the macula.
- Saccular macula lies mostly in vertical plane.
- Detects Vertical linear acceleration and change in Gravity
- Can be surgically decompressed by perforating the stapes footplate in
Meniere's disease.

3. Utricle
- Utricle lies in the Posterior part of bony vestibule.
- Parallel to earth and aligned with Lateral SCC.
- Superior to Saccule.
- Receives the five openings of the three semicircular ducts.
- Communicates with Endolymphatic duct (via Utricular duct).
- The sensory epithelium of the utricle is also called the macula.
- Macula utriculi lies mostly in horizontal plane.
- Detects Horizontal linear acceleration.

4. Semicircular ducts
- Three in number and correspond exactly to the three bony canals.
- Open in the utricle.
- Sensory receptors are located in the ampullated end and known as
Crista Ampullaris, which contains hair cells.
- Concerned with for Angular acceleration.

989
Riyadh et al. Notes
66

5. Endolymphatic Duct and Sac

¾ Endolymphatic duct:
o Formed by the union of two ducts, one each from the saccule
and the utricle.
o Contained within the vestibular aqueduct.
o Its terminal part is dilated to form endolymphatic sac which lies
between two layers of dura on the posterior surface of petrous
bone.

¾ Endolymphatic sac:
o Site of endolymph absorption.
o The 1st to appear and the last to stop growth.
o Surgically important, it is exposed for drainage or shunt
operation in Meniere's disease.
o

990
Riyadh et al. Notes
67
Inner Ear Fluids and their Circulation

1. Perilymph :
o Within the bony labyrinth.
o Resembles Extracellular fluid (ECF) and CSF.
o Rich in Na ions. (Na>K)
o Contributes to electrical potential of 0 mV in scala
vestibuli and scala tympani.
o Formed from the filtrate of blood and diffusion of CSF.
o Communicates with CSF through the aqueduct of cochlea
which opens into the scala tympani near the round
window.
o In fact this duct is not a direct communication but
contains connective tissue resembling arachnoid through
which perilymph percolates.
o Changes in blood composition are reflected much more
rapidly in perilymph than in CSF.
o Perilymph leaves the ear by drainage through venules
and through the middle ear mucosa.

2. Endolymph
o Within the membranous labyrinth.
o Resembles Intracellular fluid (ICF).
o Rich in K ions. (K>Na)
o Contributes to positive DC resting potential of +80 mV in
scala media also called cochlear duct.
o Secreted by the secretory cells of the stria vascularis of
the cochlea and by the dark cells (present in the utricle
and also near the ampullated ends of semicircular ducts).
o Gets absorbed through endolymphatic sac which lies in
the subdural space.

991
Riyadh et al. Notes
68
Organ of Corti
- Sense organ of hearing.
- Situated on the basilar membrane of Scala media.

Important components of the organ of corti:

1. Tunnel of Corti
o Formed by the inner and outer rods.
o Contains a fluid called cortilymph (similar to Perilymph).
o Exact function of the rods and cortilymph is not known.

2. Hair cells
o Receptor cells of hearing.
o Transduce mechanical sound energy into electrical energy.
¾ Inner hair cells:
o Principal transducer of motion from the basilar membrane to
nerve impulse.
o Single row.
o Fewer in number.
o Rounded, Flask-like shape with nucleus in the center.
o Low intracellular glycogen.
o Few stereocilia in curvilinear shape.
o Loose connection to tectorial membrane.
o Completely surrounding by supporting cells.
o Afferent innervation: Type I (Radial,bipolar,myelinated),
form 95% of fibers of the cochlear nerve.
o Each inner hair cell is innervated by 10-20 neurons (Low hair
to ganglion ratio) --> cochlear nucleus.
o Efferent innervation: Sparse

992
Riyadh et al. Notes
69
¾ Outer hair cells:
o Cochlear amplifier which amplify motion from the basilar
membrane.
o Source of otoacoustic emissions.
o 3 rows.
o More numerous.
o Cylindrical shaped with nucleus at base.
o High intracellular glycogen.
o Many stereocilia in "w" or "v" shape.
o Tight connection to tectorial membrane.
o Supported only at base.
o Afferent innervation: Type II (Spiral, pseudomonopolar,
unmyelinated), form 5% of fibers of the cochlear nerve.
o Each 10 outer hair cells are innervated by one neuron (High
hair to ganglion ratio) --> cochlear nucleus.
o Efferent innervation: from the auditory cortex down to the
cochlear nuclei, additional contributions from the superior
olive join and terminate predominantly on the outer hair
cells.

3. Supporting cell
o Provide nutrients and structural support.
o Deiters' cells are situated between the outer hair cells and
provide support to the latter.
o Hensens' cells lie outside the Deiters' cells.
o Claudius' cells

4. Tectorial membrane
o Fibrogelatinous structure
o Arises from the bony spiral lamina.
o Tips of stereocilia of the outer hair cells are partially
embedded in the tectorial membrance.
o Vibration of the basilar membrane causes shearing forces at
the tectorial membrane which then results in stimulation of
the hair cells.

993
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70

994
Riyadh et al. Notes
71
- Sensory Innervation of Inner Ear:
- Vestibulocochlear Nerve (CN VIII)
- Emerges between the pons and medulla
oblongata.
- Enters the internal acoustic meatus with
the Facial nerve
- Divides into vestibular branches and the
cochlear branch.
- In the internal auditory meatus, the
vestibular and cochlear nerves merge.
- During their course to the brainstem,
the Facial nerve becomes located
further up the brain.
- A small arterial branch from the Anterior
Inferior Cerebellar Artery (AICA) runs
between the CN-VII and CN-VIII on the
brainstem.
- It can be seen during vestibular schwannoma surgery and be used as
a landmark.

- Vestibular Nerve:
- Nerve cell bodies are located in the vestibular ganglion (Scarpa’s
ganglion).
- Divides into superior and inferior branches.
o Superior vestibular Nerve:
1. Ampulla of the Superior SSC.
2. Ampulla of the Lateral SSC.
3. Macula of the Utricle.
4. The Antero-superior portion of macula of the saccule.

o Inferior vestibular Nerve:

1. Ampulla of the Posterior SSC.
2. Main portion of macula of the Saccule.

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72
- Auditory Sensory System:
- Cochlear Nerve:
- Acoustic information from the hair cells is transferred by the Cochlear
nerve to the ipsilateral cochlear nuclear complex in the brain stem.
- Cochlear nerve is composed of Afferent fibers from spiral ganglion
neurones just central to the osseus spiral lamina.

- Spiral ganglion:
- Cell body of Cochlear nerve.
- Follows the course of the organ of Corti inside the modiolus.
- Sends two types of Afferent fibers type I that innervate the inner hair
- cells and type II that innervate the outer hair cells.
- Majority of spiral ganglion neurones (95%) are type I and innervate
the inner hair cells.
- 50,000 neurons innervate cochlea
¾ 95% synapse directly on Inner hair cells (Type I neurons):
o Predominantly Afferent.
o 10-20 of these neurons innervate each inner hair cells
¾ 5% synapse directly on Outer hair cells (Type II neurons):
o Predominantly Efferent.
o Each type II neuron branches to innervate ~ 10 outer hair cells
- Efferent fibres to the hair cells come from the olivocochlear bundle.
Their cell bodies are situated in superior olivary complex.
- Each cochlea sends innervation to both sides of the brain.

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73
- Vestibular Sensory System:
- Scarpa's ganglion:
- Also called Vestibular ganglion.
- Cell body of vestibular nerve.
- Consists of bipolar neurons located in the lateral part of the internal
auditory canal.
- Consists of superior and inferior group of cells associated with the
superior and inferior vestibular nerve.
- Numbers of both vestibular hair
cells and nerve cells in Scarpa's
ganglion are found to be reduced
in the ears of older people.
- Like the bodies of the human
spiral ganglion, the perikarya of
the vestibular ganglion cells are
unmyelinated and surrounded by a thin sheath of Schwann cell.

- Three distinct types of Vestibular Afferents

1. Calyx:
o Terminate exclusively on type I hair cells
o May terminate on one or several hair cells
o Thicker axons
o Terminate in central zone of crista ampullaris and near striola
o Irregularly firing; sensitive to galvanic stim, not angular mov’t
2. Dimorphic:
o Endings on both type I and type II hair cells
o Most prevalent (probably)
o Can be thin or thick
o Terminate in central, intermediate and peripheral zones
o Combo of both wrt sensitivity/firing; depends on location
3. Bouton:
o Terminate only on type II hair cells
o Thinner axons
o Terminate in peripheral zone of crista ampullaris
o Lower galvanic and natural stim thresholds; regular firing with
slower conduction velocities.

997
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Riyadh et al. Notes
75
- All vestibular epithelium has efferent fibres; function unknown.
- The vestibular system plays a Lesser role for the control of human
posture and balance.
- The main peripheral component of the vestibular system is the
labryinth.
- Labyrinth has sensory cells known as Hair cells that transduce physical
motion into neural impulses.
- Motions in the labyrinth are due to:
o Head movements
o Inertial effects due to gravity
o Ground-borne variations
- Labyrinth consists of:
o 2 otolith organs ( Utricle and Saccule)
o 3 SCC.
- Utricle and saccule are specialized primarily to respond to:
o Linear accelerations of the head.
o Static head position relative to the gravitational axis
- SCC are specialized for responding to:
o Rotational accelerations of the head in 3 planes.

- Neuroepithelium of Vestibular system:

- Composed of sensory hair cells in contact with a gelatinous membrane.
- Hair cell bundles in each vestibular organ have specific orientations.
- The organ as a whole is responsive to displacements in ALL directions.
- Glutamine is the neurotransmitter.
- There are now data suggesting that the sensory vestibular epithelia
may regenerate in mammals including man, which may explain the
return of symptoms after gentamicin treatment in patients with
Meniere's disease.

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76
- Two types of sensory hair cells:

1. Type I:
o Flask-shaped.
o Surrounded by one nerve Chalice (cup or goblet) formed by the
terminal end of the Afferent nerve fiber of the vestibular nerve.
o Correspond to the inner hair cells of the organ of Corti.
o Stereocillia & kinocilium arrangement.

2. Type II:
o Cylindrical in shape.
o Same arrangement of stereocillia & kinocilia as the type I cells.
o One or more Afferents
o Direct or indirect Efferents

- Hair cell arrangement:

- The upper surface of the hair cell contains approximately 70 stereocilia
and one kinocilium arranged with the longest stereocilia positioned
adjacent to the kinocilium.
- The upper surface of the cell contains a thicker region, called the
'Cuticular plate', into which the stereocilia extend their rootlets.

1. Kinocilium:
o Tallest.
o Near edge of top hair cell
o A true cilium demonstrating the 9 + 2 arrangement of
microtubules.

2. Stereocilia:
o Arranged in rows.
o Sterocilia closer to kinocilia are longer.

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Riyadh et al. Notes
77
- Deflection of stereocilia TOWARD the kinocilium results in Increased
vestibular neuronal firing rate.
- Deflection of stereocilia AWAY from the kinocilium results in
Decreased vestibular neuronal firing rate.
- Hair cells in utricle and saccule act similarly to SCC in regard to the
kinocilia and stereocilia, however, the utricle and saccule's hair cells
are arranged in a specific pattern.

- Sensory Hair cells are found in:

1. Ampullae of SCCs.
2. Macula of Otolith organs (utricle and saccule).

- Ampullae of SCC:
- Ampullae are bulbous expansion located at
the base of SCC next to the utricle.
- Houses the sensory epithelium known as
Crista that contains the hair cells
- Hair bundles extend out of the crista into a
gelatinous mass known as the Cupula.
- Cupula bridges the width of the ampulla,
forming a viscous barrier through which
endolymph cannot circulate.
- The relatively compliant cupula is distorted
by movements of the endolymph.
- When the head turns in the plane of one of
the semicircular canals, the inertia of the
endolymph produces a force against the
cupula, distending it away from the
direction of the head movement.

- Distention of the cupula away from the direction of head movement

causes a displacement of the hair bundles within the crista.
- Linear accelerations of the head produce EQUAL forces on the 2 sides
of the cupula, so the hair bundles are NOT displaced

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Riyadh et al. Notes
78
- SCC sense Head rotation either arising from self induced movements
or from angular accelerations of the head imparted by external forces.
- Unlike the saccular and utricular maculae, ALL hair cells in the crista
within each SCC are organized with their kinocilia pointing in the SAME
direction.
- When the cupula moves in the Appropriate direction, the entire
population of hair cells is Depolaized and the activity in ALL of the
innervating axons is Increased
- When the cupula moves in the Opposite direction, the population is
Hyperpolarized and neuronal activity Decreases.

- The specific gravity of the cupula is approximately 1.0, which is same

as that of the Endolymph.
- This matching of the specific gravity is necessary to prevent the cupula
from floating upward in certain head positions and causing an enduring
nystagmus.
- Disruption of this match in specific gravity is likely the cause of
Postalcoholic Nystagmus.

- Each semicircular canal works in concert with the partner located on

the other side of the head that has its hair cells aligned oppositely.

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79
- Three pairs:
o 2 pairs of horizontal canals
o Superior canal on each side working with the Posterior canal on
the other side, both are in same plane.

- Head rotation deforms the cupula in opposing directions for the 2

partners, resulting in opposite changes in their firing rates.
- Orientation of the horizontal canals makes them selectively sensitive to
rotation in the horizontal plane.
- Hair cells in the canal Toward which the head is turning are
Depolarized, while those on the other side are Hyperpolarized.

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80

- In Horizontal SCC:
o Kinocilia are located on the Utricular side.
o Afferents are stimulated when endolymph flows against the
utriculus.
o Displacement of stereocilia TOWARD the Utricle (AmpulloPetal)
causes Increased vestibular neuronal firing rate
(depolarization).
o Displacement of stereocilia AWAY from the Utricle
(AmpulloFugal) causes Decreased vestibular neuronal firing
rate (Hyperpolarization).

- In Vertical SCC (Posterior and Superior):

o Kinocilia are located on the Semicircular canal side.
o Afferents are stimulated when endolymph flows against the
Ampulla.
o Displacement of stereocilia TOWARD the Utricle (AmpulloPetal)
causes Decreased vestibular neuronal firing rate
(Hyperpolarization).
o Displacement of stereocilia AWAY from the Utricle
(AmpulloFugal) causes Increased vestibular neuronal firing
rate. (depolarization).

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Riyadh et al. Notes
81
- Macula of Otolith organs
- Both the Saccule and Utricle contain a thickened sensory epithelium
called Macula.
- Macula consists of :
o Hair cells
o Supporting cells

- Gelatinous layer:
o Overlying the hair cells and their hair bundles.
- Otolithic membrane:
o Fibrous structure above the gelatinous layer.
- Otoconia:
o Also called Statoconia.
o Calcium crystals containing material consisting of a multitude of
small cylindrical and hexagonally shaped bodies with pointed
ends
o Aanchored and partially embedded in the otolithic membrane.
o Make the otolithic membrane heavier than the structures and
fluids surrounding it.

- Because of the heaviness by the otoconia, when the head tilts, gravity
causes the membrane to shift relative to the sensory epithelium.
- The resulting shearing motion between the otolithic membrane and the
macula displaces the hair bundles, which are embedded in the lower
gelatinous surface of the membrane.

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Riyadh et al. Notes
82

- Striola:
o Specialized area in the utricle and saccule.
o Divides the hair cells into 2 populations with OPPOSING
polarities.
o Contain more Type I cells.
o Forms an axis of mirror symmetry such that hair cells on
opposite sides of the striola have opposing morphological
polarizations.
o A tilt along the axis of the striola will excite the hair cells on one
side while inhibiting the hair cells on the other.
o Polarization of hair cells occurs point TOWARD striola in the
Utricular macula and AWAY from the striola in the saccular
macula.

- Saccular macula:
o Oriented in the VERTICAL plane.
o Detects Vertical linear acceleration and change in Gravity.
o Ex: Up/down and forward backward movements in the sagittal
plane.
o Polarization of hair cells occurs point AWAY the striola.

- Utricular macula:
o Oriented in the HORIZONTAL plane.
o Detects Horizontal linear acceleration.
o Ex: Sideways head tilts and rapid lateral displacements would
be detected by the utricle.
o Polarization of hair cells occurs point TOWARD the striola.

- Structure of the otolith organs enables them to sense both Static and
Transient displacements.
- Titling the head relative to the gravitational axis would be a Static
displacement sensed by the otolith organs
- Translational movements of the head would be a Transient
displacement sensed by the otolith organs.

1005
Riyadh et al. Notes
83
- Note that the maculae respond only to changes in acceleration or
velocity of head movement, they do NOT report on unchanging head
positions.

- Other cell types of Macula:

1. Supporting cells:
o Secrete Extracellular macromolecules of cupula and otolith
membrane.
2. Dark cells:
o Found in all sensory epithelia of membranous labyrinth, except
the saccule which is believed to lack production of endolymph.
o Produce ionic composition of Endolymph.
o Involved in the degradation and resorption of dislodged
otoconia.

- Blood Supply of Inner Ear:

- Labyrinthine artery
o Supplies the entire labyrinth.
o Branch of the Anterior inferior cerebellar artery (AICA) (85%-
100% cases) or Basilar artery (<15% cases).
o Accompanies the vestibulocochlear nerve through the internal
acoustic meatus.
o Divides into cochlear and vestibular branches that supply the
cochlear and vestibular structures

1006
Riyadh et al. Notes
84

- Anterior Vestibular Artery:

o Superior portion of Utricle and Sacule
o Superior and Horizontal SCC.
- Posterior Vestibular Artery:
o Inferior portion of Utricle and Sacule
o Posterior SCC.
- Main Cochlear Artery:
o ALL cochlea except One-Third of Basal turn.
- Cochlear Branch:
o One-Third of Basal turn.

1007
Riyadh et al. Notes
85

- Venous drainage is through three veins, namely internal auditory vein,

vein of cochlear aqueduct and vein of vestibular aqueduct which
ultimately drain into inferior petrosal sinus and lateral venous sinus.

- Blood supply to the inner ear is independent of blood supply to middle

ear and bony otic capsule, and there is no cross circulation between
the two.

- Blood supply to cochlea and vestibular labyrinth is segmental,

therefore, independent ischemic damage can occur to these organs
causing either cochlear or vestibular symptoms.

x NO LYMPHATIC DRAINAGE OF INNER EAR.

1008
Riyadh et al. Notes
86
Eustachian Tube Anatomy:

- Pharyngotympanic Tube.
- A dynamic channel that links Middle ear with Nasopharynx.
- Derived from 1st Pharyngeal Pouch.
- In Adults:
o 36 mm in length
o Reach adult size at age 7.
o Runs downwards, forwards and medially from its tympanic end.
o Forming an angle of 45° with the horizontal.

- Divided into two parts:

1. Bony Part:
o Lateral 1/3.
o 12 mm in length.
o Runs through Squamous and Petrous part of Temporal bone.
o Thin plate of bone forms the Roof, separating ET from Tensor
Tympani muscle above.
o Carotid canal lies Medially and can impinge on Bony ET.
o In cross section, ET is Triangular or rectangular with the
horizontal diameter being the greater.
o Tympanic End of ET:
ƒ At the Lateral end of the Bony part.
ƒ Oval in shape
ƒ Measures 5×2 mm.
ƒ Situated in Anterior wall of Middle Ear, above level of
floor.
o Isthmus:
ƒ Narrowest part of ET.
ƒ 0.5 mm in Diameter.
ƒ At Junction of Bony part and Fibrocartilaginous part.

2. Fibrocartilaginous Part:
o Medial 2/3.
o 24 mm in length.
o Made of a single piece of cartilage folded upon itself.
ƒ Forms the Medial lamina, Roof and a part of Lateral
lamina.
ƒ Rest of Lateral lamina is made of Fibrous membrane.
o Nasopharyngeal End of ET:
ƒ At the Medial end of the Fibrocartilaginous part.
ƒ Slit-like, vertically.
ƒ The cartilage at this end raises an elevation called Torus
Tubarius:
x Situated in Lateral wall of Nasopharynx.
x 1-1.25 cm behind Posterior end of Inferior
Turbinate.

1009
Riyadh et al. Notes
87

- Lining of Eustachian Tube:

- Pseudostratified ciliated columnar epithelium with mucous secreting
goblet cells (Respiratory Mucosa).
- At Nasopharyngeal end of ET, the mucosa is truly respiratory; but in
passing along the tube towards Middle ear, Number of goblet cells and
glands decreases, and the ciliary carpet becomes less profuse.
- Cilia beat in the direction of Nasopharynx and helps to drain secretions
and fluid from Middle ear into Nasopharynx.
- Submucosa of Cartilaginous part of ET is rich in seromucinous glands.

1010
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88
- Muscles Related to Eustachian Tube:
1. Tensor veli palatini.
2. Levator veli palatini.
3. Tensor Tympani.
4. Salpingopharyngeus.

MUSCLE ORIGIN INSERTION NERVE SUPPLY ACTION

Tensor Veli Palatini Spine of Forms the Nerve to Medial Medial fibers
(Dilator Muscle) Sphenoid. Palatin Pterygoid from are attached to
Aponeurosis Mandibular Branch Lateral lamina
Eustachian with Tensor (V3) of Trigeminal of ET.
Tube. Veli Palatini Nerve CN-V
from other Contracts to
side. open ET lumen.

Tenses soft
palate
Levator Veli Palatini Petrous Palatin Pharyngeal Plexus Assist in
part of Aponeurosis (Vagus Nerve CN-X) opening ET.
Temporal
bone. Raises the
Palate.
Eustachian
Tube.

SalpingoPharyngeous Eustachian Blends with Pharyngeal Plexus Assist in

Tube. PalatoPharyng (Vagus Nerve CN-X) opening ET.
eous.
Elevates
Pharynx.

Tensor Tympani Wall of ET Neck of Mandibular Branch Dampens down

and wall of Malleus. (V3) of Trigeminal Vibrations of
Its own Nerve CN-V TM.
canal.

1011
Riyadh et al. Notes
89
- Elastin Hinge:
- Elastin fibers found in junction of Medial and Lateral lamina at the Roof
of Cartilgenous part of ET.
- Keeps ET closed by its recoil, when no longer acted upon by Tensor
Veli Palatini (Dilator Muscle).

- Ostmann's Fat Pad:

- Mass of fatty tissues related Laterally to Membranous part of
Cartilaginous tube.
- Keeps ET closed and protect it from reflux of Nasopharyngeal
secretions.

- Arterial blood supply of ET:

1. Ascending Pharyngeal Artery.
2. Middle Meningeal Artery.

- Venous blood drainage of ET:

- Pharyngeal plexus

- Lymphatics draiange of ET:

- Retropharyngeal nodes.

- Nerve Supply of ET:

- Tympanic branch of CN-IX:
o Sensory and Parasympathetic Secretomotor Fibers to ET
mucosa.

1012
Riyadh et al. Notes
90

1013
Riyadh et al. Notes
91
- Eustachian Tube in Infants:
o Shorter.
o Wider.
o More Horizontal.
o More susceptible to regurgitation from Nasopharynx into Middle
Ear with feeding.

- Movement of ET:
1. Passive closure by:
o Elastic Recoil.
o Passive pressure from surrounding tissue.
2. Active opening by:
o Tensior veli platini muscle.

- Main Functions of Eustachian Tube:

1. Ventilation and Regulation of Middle Ear Pressure.
2. Protection against:
ƒ Nasopharyngeal sound pressure.
ƒ Reflux of Nasopharyngeal secretions.
3. Middle Ear clearance and drainage of secretions.

- Ventilation and Regulation of Middle Ear Pressure:

- For Normal hearing:
o Pressure on two sides of TM should be Equal.
o Negative or Positive Pressure in Middle ear affects hearing.
- ET should open periodically to equilibrate Air pressure in Middle ear
with Ambient pressure.
- Normally, ET remains closed and opens intermittently during:
o Swallowing
o Yawning
o Sneezing
- ET opening function is Poor in:
o Recumbent position and during sleep due to Venous
Engorgement.
o Infants and Young children.

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92
- Protective Functions:
- High sound pressures from Nasopharynx can be transmitted to Middle
ear if Tube is open and interfering with normal hearing (Patulous
Eustachian Tube)
- ET remains closed normally and protects Middle ear against these
sounds.
- ET also protects from reflux of Nasopharyngeal secretions into the
Middle ear.
- This reflux occurs more readily if:
o ET is wide in diameter (patulous tube).
o Short in length, (infants).
o Perforated TM (cause for persistence of middle ear infections).
o High pressures in Nasopharynx (Forceful nose blowing, closed-
nose swallowing as in adenoid hypertrophy or bilateral nasal
obstruction)

- Clearance of Middle ear secretions:

- Mucous membrane of ET and Anterior part of Middle ear is lined by
Ciliated columnar cells.
- Cilia beat in direction of Nasopharynx to clear secretions and debris in
Middle ear.
- Clearance function is further augmented by active opening and closing
of the tube.

- Eustachian Tube Function Tests

1. Valsalva Test.
2. Toynbees's Test
3. Tympanomtry

- Valsalva Test:
- Principle:
o To build positive pressure in Nasopharynx so that Air enters ET
into Middle ear.
- Method:
o Exhalation against a closed airway.
o Closing the Mouth and pinching the Nose.
- Results:
o Normally:
ƒ Air enters Middle ear through ET.
ƒ TM move outwards ( by Otoscope).
o TM perforation:
ƒ Hissing sound is produced.
o Failure of this test does not prove blockage of ET because only
65% of persons can successfully perform this test.
- Contraindications:
o Presence of atrophic scar in TM which can rupture.
o Presence of infection of Nose and Nasopharynx (Risk of Reflux).

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93
- Toynbee's Test:
- Principle:
o To build Negative pressure in Nasopharynx so that Air enters ET
From Middle ear.
- Method:
o Swallowing with pinched Nose.
- Results:
o Normally:
ƒ Air enters Nasopharynx from Middle ear through ET.
ƒ TM move inwards ( by Otoscope).

- Tympanometry (Inflation-deflation Test):

- Principle:
o Normal ET is able to equilibrate Middle ear and Ambient
pressure.
- Method:
o Positive and Negative pressures (-200 or +200 mm of H2O) are
created in EAC.
o Patient swallows repeatedly (5 times in 20 seconds).
- Results:
o Normally:
ƒ Equilibration of positive and negative pressures to
Ambient pressure.
ƒ Done both in patients with perforated or intact TM.
ƒ Can be used to find the patency of VT.

- Disorders of Eustachian Tube (ET)

- ET Obstruction:
- Normally, ET is closed.
- Opens intermittently during swallowing, yawning and sneezing due to
contraction of Tensor veli palatini muscle.
- Air (O2, Co2, Nitrogen, Water vapour) normally fills Middle ear and
Mastoid.
o Lower O2 & CO2 and higher N2 compared to Atomosphere.
o Similar to venous gas.
- If ET is Blocked:
o Initially, Oxygen is Absorbed then other gases are Absorbed.
o Æ Negative pressure in Middle ear.
o Æ Retraction of TM.
o Æ If Negative pressure is increased
o Æ ET will be locked.
o Æ Collection of Transudate and later Exudate.
o Æ Atelectatic ear / Perforation.
o Æ Retraction pocket / Cholesteatoma.
o Æ Erosion of Incudo-Stapedial joint.

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94
- Causes of ET Ostruction
1. URTI.
2. Allergy.
3. Sinusitis.
4. DNS.
5. Hypertrophic Adenoid:
o Mechanical obstruction of ET.
o Reservoir for Pathogenic organisms.
o Adenoidectomy helps with OME and Recurrent AMO.
6. Nasopharyngeal Tumor/mass.
7. Cleft Palate:
o Abnormalities of Torus Tubarius (High elastin density making
tube difficult to open).
o Tensor veli palatini muscle does not insert into Torus tubarius in
40% cases of cleft palate.
o OME is common even after cleft palate repair.
o Requires insertion of VT.
8. Down's syndrome.
o Poor tone of Tensor Veli Palatini muscle.
o Abnormal shape of Nasopharynx.
o OME is common.
o Requires insertion of VT.

- Signs and Symptoms of ET Obstruction:

- Otalgia, CHL, Popping sensation, Tinnitus and Vertigo.
- Retracted TM, Congested TM, Transudate behind TM imparting it an
Amber colour and a Fluid level.

- Retraction Pockets and ET:

- Air passes from ET to Mesotympanum, Attic,
Aditus, Antrum and Mastoid air cell system.
- Mesotympanum communicates with Attic via:
1. Anterior Isthmus:
ƒ Between Tensor Tympani tendon
and Stapes.
2. Posterior Isthmus:
ƒ Between Stapedius tendon and
Pyramid, and Short Process of
Incus.

1017
Riyadh et al. Notes
95
- Any obstruction in the pathways of ventilation can cause Retraction
pockets or Atelectasis of TM:
o Obstruction of ET Æ Total Atelectasis of TM.
o Obstruction in Middle ear Æ Retraction pocket in posterior
part of Middle ear while Anterior part is ventilated.
o Obstruction of Isthmi Æ Attic Retraction pocket.
o Obstruction at Aditus Æ Cholesterol granuloma and collection
of mucoid discharge in mastoid air cells, while Middle ear and
Attic appear Normal.

- Principles of Management of Retraction pockets and Atelectasis of

middle ear would entail Correction/repair of the irreversible pathologic
processes and establishment of the ventilation.

- Patulous Eustachian Tube:

- ET is abnormally patent.
- Mainly idiopathic.
- Acquired:
o Scarring post Adenoidectomy.
o Rapid weight loss.
o Pregnancy (Third trimester).
o Multiple Sclerosis.

- Signs and Symptoms:

- Distorted Autophony (Abnormal perception of one's own breath and
voice sounds – most common)
o Echoing occasionally severe enough to interfere with speech
production
- Fluctuating Aural fullness.
- Roaring Tinnitus synchronous with nasal respiration.
- Audible respiratory sounds.
- Synchronous TM movement with Respiration can be seen on otoscopy.
- Symptoms improve when Supine.

- Self-limiting and does not require treatment.

- Weight gain, oral administration of potassium iodide is helpful but
some long-standing cases may require cauterisation of the tubes or
insertion of a grommet.

1018
Riyadh et al. Notes

Physiology of Auditory System: 96

External Ear

9 Head and external ear play passive role in hearing

9 pinna helps to differentiate sound in front of or behind listener
9 EAC: open at one end, so behaves like a quarter-wave resonator;
9 resonant frequency (f0) depends on length, not curvature ( for 2.5
cm, it equals 3.5 kHz (8 kHz for infants) )
9 Head: attenuates sounds if width of head is greater than sound’s
wavelength (> 2 kHz); called head shadow effect;
9 interaural intensity difference of 5-15 dB helps with localization;
interaural time difference of 0.6 ms helps too
9 Interaural intensity difference.
9 Interaural time difference.
9 Pinna effect.
9 The auditory brainstem processes interaural timing and amplitude
differences between ears to determine the location of the sound
source.

1019
Riyadh et al. Notes

Middle Ear 97
• Effects of conductive system defects and hearing loss:
 Isolated TM perforation: 30-45 dB CHL
 TM perforation and ossicular chain discontinuity: 40-50 dB CHL
 Intact TM and ossicular chain discontinuity: 55-60 dB CHL
• Roles of TM in addition to above: protects middle ear from EAC
contents; provides air cushion to prevent insufflation of foreign
material from the NP via the ET
• Less than half of the power entering the middle ear gets to cochlea;
much is absorbed by ligaments and the rest of the middle ear
(remember that a 50% loss of power is a loss of only 3 dB intensity)

Middle ear muscles: tensor tympani (CN V) and stapedius (CN VII)
 Stapedius contracts in response to loud sounds (> 80 dB
SPL); stiffens ossicular chain; limits low frequency (< 2 kHz)
sound transmission to cochlea; 10 ms latency; no good for
bursts

1020
Riyadh et al. Notes

Auditory Neural Pathways and 98their Nuclei:

9 Hair cells are innervated by dendrites of bipolar cells of spiral
ganglion which is situated in Rosenthal's canal (canal running
along the osseous spiral lamina).

9 Axons of these bipolar cells form the cochlear division of CN

VIII and end in the cochlear nuclei , the dorsal and ventral, on
each side of the medulla.
9 the ascending auditory pathways, sequentially, from below
upwards, are:
Remember the mnemonic E.COLI-MA

A. Eighth nerve
B. Cochlear nuclei
C. Superior olivary complex
D. Nucleus of lateral lemniscus
E. Inferior colliculus
F. Medial geniculate body (thalamus)
G. Auditory cortex.

• Auditory pathways from the right cochlea.

• Note bilateral route through brainstem and bilateral cortical
representation.

1021
Riyadh et al. Notes

9 Most fibres from the cochlear 99

nucleus cross to contra sup olivary
complex; some stay ipsi
9 The auditory fibres travel via the ipsilateral and contralateral routes
and have multiple decussation points. Thus each ear is
represented in both cerebral hemispheres.
9 The area of cortex, concerned with hearing is situated in the
superior temporal gyrus" within sylvian fissure of temporal lobe"
(Brodmann's area 41).

Mechanism of Hearing
9 sound signal in the environment is collected by the pinna, passes
through external auditory canal and strikes the tympanic
membrane.
9 Vibrations of the tympanic membrane are transmitted to stapes
footplate through a chain of ossicles coupled to the tympanic
membrane.
9 Movements of stapes footplate cause pressure changes in the
labyrinthine fluids which move the basilar membrane.
9 move the basilar membrane stimulates the hair cells of the organ
of Corti.
9 hair cells act as transducers and convert the mechanical
energy into electrical impulses which travel along the auditory
nerve.
9 Thus, the mechanism of hearing can be broadly divided into:

• 1. Mechanical conduction of sound (conductive apparatus).

• 2. Transduction of mechanical energy to electrical impulses
(sensory system of cochlea).
• 3. Conduction of electrical impulses to the brain (neural pathways).

1022
Riyadh et al. Notes

1. Conduction of Sound 100

9 person under water cannot hear any sound made in the air because
99.9% of the sound energy is reflected away from the surface of
water because of the impedance offered by it.
9 similar situation exists in the ear when air-conducted sound has to
travel to cochlear fluids. Nature has compensated for this loss of
sound energy by interposing the middle ear which converts sound
of greater amplitude, but
lesser force, to that of lesser amplitude but greater force (( ME act as
mechanical transformer))
9 This function of the middle ear is called impedance matching
mechanism or the transformer action. to compensate the sound
energy lost during its transmission from air to liquid
medium. it is accomplished by:

• (a) Lever action of the ossicles. Handle of malleus is 1.3 times

longer than long process of the incus, providing a mechanical
advantage of 1.3.

• (b) Hydraulic action of tympanic membrane

9 The area of tympanic membrane is much larger than the area of

stapes footplate, the average ratio between the two being 21:1.
9 As the effective vibratory area of tympanic membrane is only two-
thirds, the effective areal ratio is reduced to 14:1, and this is the
mechanical advantage provided by the tympanic membrane
The product of areal ratio and lever action of ossicles is 18:1.
• According to some workers (Wever & Lawrence) out of a total of 90
mm2 area of human tympanic membrane, only 55 mm2 is functional
and given the area of stapes footplate (3.2 mm2), the areal ratio is
17:1 and total transformer ratio (17 × 1.3) is 22.1 or
approximately 25–30 dB gain increase in sound pressure

1023
Riyadh et al. Notes

101

1024
Riyadh et al. Notes

• (c) Curved membrane effect.

102
9 Movements of tympanic membrane are more at the periphery than
at the center where malleus handle is attached. This too provides
some Force.

9 The curved membrane buckling advantage is 2 to 1

Phase differential between oval and round windows

9 Sound waves striking the tympanic membrane do not reach the
oval and round windows simultaneously.
9 There is a preferential pathway to the oval window because of the
ossicular chain. when oval window is receiving wave of
compression, the round window is at the phase of rarefaction.
9 If the sound waves were to strike both the windows simultaneously,
they would cancel each other's effect with no movement of the
perilymph and no hearing.
9 This acoustic separation of windows is achieved by the presence of
intact tympanic membrane protects the round window .
9 Phase differential between the windows contributes 4 dB when
tympanic membrane is intact.

1025
Riyadh et al. Notes

103

Natural resonance of external and middle ear

9 Resonance Frequencies: natural frequencies that vibrate a mass
with the least amount of force
9 Inherent anatomic and physiologic properties of the external and
middle ear allow certain frequencies of sound to pass more easily
to the inner ear due to their natural resonances.
• Concha: 4000–6000 Hz
• EAC: 2000–3000 Hz (primary frequencies of speech)
• TM: 800–1600 Hz
• Ossicles: 500–2000 Hz (most efficiently transmitted by ossicular
chain)
• Middle Ear: 800 Hz
9 Thus greatest sensitivity of the sound transmission is between 500
and 3000 Hz and these are the frequencies most important to man
in day to day conversation
9 EAC and pinna give gain of 15 dB at 3 kHz range (10 dB from 2 to 5
kHz); this is one of the reasons for 4 kHz notch with noise-induced
hearing loss (boilermaker notch).

2. Transduction of Mechanical Energy to Electrical Impulses

9 Movements of the stapes footplate, transmitted to the cochlear

fluids, move the basilar membrane, setting up shearing force
between the tectorial membrane and the hair cells.
9 The distortion of hair cells gives rise to cochlear microphonics which
trigger the nerve impulse

1026
Riyadh et al. Notes

104

.
9 Place Theory (Tonotopic Organization of the Cochlea) A sound
wave, depending on its frequency, reaches maximum amplitude on
a particular place on the basilar membrane and stimulates that
segment (travelling wave theory of von Bekesy).
9 Higher frequencies are represented in the basal turn of the cochlea
and the progressively lower ones towards the apex

1027
Riyadh et al. Notes

105
3. Neural Pathways
9 Hair cells get innervation from the bipolar cells of spiral ganglion.
9 Central axons of these cells collect to form cochlear nerve which
goes to ventral and dorsal cochlear nuclei. From there, both crossed
and uncrossed fibres travel to the superior olivary nucleus, lateral
lemniscus, inferior colliculus, medial geniculate body and finally
reach the auditory cortex of the temporal lobe.

Electrical Potentials of Cochlea and CN VIII

Four types of potentials have been recorded; three from the cochlea
and one from CN VIII fibres. They are:

1. Endocochlear (Endolymphatic) potential

9 It is a direct current (DC) potential recorded from scala media.
9 It is +80 mV and is generated from the stria vascularis by Na+/K+-
ATPase pump and provides source of energy for cochlear
transduction.
9 It is present at rest and does not require sound stimulus.
9 This potential provides a sort of "battery" of the cochlea, to drive
the current through hair cells when they move in response to a
sound stimulus.
9 Stimulation of hair cells produces intracellular potential of -40 mV.
This provides flow of current of 120 mV through the top of hair
cells.
o Metabolic presbycusis: HL associated with altered endo-
cochlear potentials; from endolymph problems/hydrops

1028
Riyadh et al. Notes

2. Cochlear microphonic (CM) 106

9 It is an alternating current (AC) potential.
9 voltage recorded within cochlea near round window
9 When basilar membrane moves in response to sound stimulus,
electrical resistance at the tips of hair cells changes allowing flow of
K+ through hair cells and produces voltage fluctuations called
cochlear microphonic.
9 wave form mirrors motion of basilar membrane

3. Summating potential (SP)

9 It is a DC potential and follows "envelope" of stimulating sound.
9 It is produced by hair cells.
9 It may be negative or positive.
9 SP has been used in diagnosis of Mèniere's disease.
9 It is superimposed on VIII nerve action potential.
9 They differ from action potentials in that:
 They are graded rather than all or none phenomenon,
 have no latency
 not propagated
 no post-response refractory period.

4. Compound (Whole nerve) action potential

9 It is an all or none response of auditory nerve fibres.
9 recorded with gross electrode near the round window or auditory
nerve, with high-frequency signals
 Amplitude increases with intensity from 40 to 50 dB
 Latency decreases as stimulus intensity increases

1029
 107
dB and sound energy: dB SL is a unit for threshold of hearing in an audiogram. A
sound of 20 dB is 100 fold increase in sound energy.

Natural resonance frequency of :

EAC = 3000 Hz
Tympanic membrane = 800 - 1600 hz
middle ear = 800 hz
oscular chain = 500 - 2000 hz
Riyadh et al. Notes
108

Audiology and Hearing Assessment:

- Sound:
o Form of energy produced by a vibrating object.

- Sound wave:
o Consists of compression and rarefaction of molecules of the
medium (air, liquid or solid) in which it travels.

- Sound velocity:
o Different in different media.
o In the air, at 20°C, at sea level, sound travels 344 m/sec.
o Travels faster in liquid and more fastes in a solid medium.

1030
Riyadh et al. Notes
109
- Sound Pitch (Hz):
o Subjective sensation produced by Frequency of sound.
o Higher the frequency, greater is the pitch.
o Sound Frequency is the number of cycles/second.
o Measured by Hertz (Hz).
o Sound of 1000 Hz means 1000 cycles/second.
o Normal person can hear frequencies of 20-20,000 Hz.
o Routine audiometry tests only 125-8000 Hz.
o Frequencies of 500, 1000 and 2000 Hz are called speech
frequencies as most of human voice falls within this range.
o Pure tone average is the average threshold of hearing in these
three speech frequencies which corresponds to the speech
reception threshold.

- Pure tone:
o Single frequency sound.
o Sound of 250, 500 or 1000 Hz.
o In pure-tone audiometry, we measure the threshold of hearing
in decibels for various pure tones from 125 to 8000 Hz.

- Complex sound:
o Sound with more than one frequency.
o Human voice is a complex sound.

- Loudness (dB):
o Subjective sensation produced by Intensity of sound.
o More the intensity of sound, greater the loudness.
o Measured in decibels.

1031
Riyadh et al. Notes
110
- Hearing Threshold:
o Minimal intensity which a normal healthy person can hear.
o Vary from person to person.
o Zero level on the audiometer (0 dB):
ƒ The least intensity for average normal ear to perceive a
specific frequency 50% of the time

- Hearing level (HL):

o Sound pressure level (SPL) produced by an audiometer at a
specific frequency.
o It is measured in decibels with reference to audiometric zero.
o If an audiometer delivers a sound at 70 dB, it is represented as
70 dB HL.

- Sensation level (SL):

o Level of sound above the threshold of hearing for an individual.
o If someone is tested at 40 dB SL, it means he was tested at 40
dB above his threshold.
o For a normal person, this would be a sound of 0 + 40, i.e. 40 dB
HL, but for one with a hearing loss of say 30 dB, it would be 30
+ 40, i.e. 70 dB HL.
o In other words, sensation level refers to the sound which will
produce the same sensation, as in normally hearing person.
o In speech audiometry, discrimination scores are tested at 30 to
40 dB SL.
o Stapedial reflex is elicited with a sound of 70-100 dB SL

- Noise:
o Aperiodic complex sound.
o Used for masking by keeping one ear busy by noise while the
other is being tested.
o Types of noise:
ƒ Narrow-band noise:
x Contains certain frequencies with smaller frequency
range.
x Used to mask the test frequency in PTA.

white Broad-band noise:
x Contains all frequencies in audible spectrum.
x Used for masking in speech audiometry.

1032
 Riyadh et al. Notes
111

Assessment of Hearing:

- Hearing loss can be of three types:

1. Conductive Hearing Loss (CHL):
o Any disease process interfering with the conduction of sound
from External ear to Stapediovestibular joint.
o Cause may lie in:
1. External Ear (Obstructions)
2. Tympanic Membrane (Perforation)
3. Middle Ear (Fluid)
4. Ossicles (Fixation or Disruption)
5. Eustachian Tube (Obstruction)
6. Inner ear (SCDS/Third window effect)
2. Sensorineural Hearing Loss (SNHL):
o Cochlear HL:
ƒ Hearing loss due to lesions of Cochlea.
ƒ Examples:
x Noise-induced SNHL
x Ototoxicosis
x Presbycusis
x Meniere’s Disease
x Labrynthitis
x Autoimmune
x Inner ear malformation
o Retro-cochlear HL:
ƒ Hearing loss due to lesions of CN-VIII or central auditory
system.
ƒ Examples:

CPA tumors, neural presbycusis, acoustic neuroma, meningioma .

MCQ

3. Mixed Hearing Loss:

- Both CHL and SNHL are present in the same ear.
o Air-Bone gap indicates CHL
o Impairment of bone conduction indicats SNHL.
- Examples:
o Advance Otosclerosis.
o Advance CSOM.
o Mixed pathology.

1033
112
Riyadh et al. Notes
113
- While assessing Auditory function it is important to find out:
1. Type of Hearing Loss:
o CHL
o SNHL
o Mixed HL
2. Degree of Hearing Loss:
o Mild
o Moderate
o Moderately Severe
o Severe
o Profound
o Total
3. Site of Lesion:
o If CHL:
ƒ External Ear
ƒ TM
ƒ Middle Ear
ƒ Ossicles
ƒ Eustachian tube
ƒ Inner ear defects
o If SNHL:
ƒ Cochlear
ƒ Retrocochlear
4. Cause of Hearing Loss:
o Congenital
o Traumatic
o Infective
o Neoplastic
o Degenerative
o Metabolic
o Ototoxic
o Vascular
o Autoimmune

1034
Riyadh et al. Notes
114
- Clinical Tests of Hearing:

- Finger Friction Test:

- Rough but quick method of screening.
- Rubbing or snapping the thumb and a finger close to patient's ear.

- Tuning Fork Test:

- Performed with tuning forks of different frequencies (128, 256, 512,
1024 Hz).
- For routine clinical practice, tuning fork of 512 Hz is ideal.
o Forks of Lower Frequencies ( 128 and 256 Hz):
ƒ Produce sense of bone vibration.
o Forks of Higher Frequencies ( 1024 Hz):
ƒ Have a shorter decay time.

- Air Conduction (AC):

o Vibrating fork is placed vertically about 1 cm away from
the opening of external auditory meatus.
o Sound waves are transmitted through TM, Middle ear and
Ossicles to Inner ear.
o Testing both Conducting mechanism and Cochlea
o Normally, hearing through air conduction is louder and
heard twice as long as through Bone conduction route.

- Bone Conduction (BC):

o Footplate of vibrating tuning fork is placed firmly on
Mastoid bone.
o Cochlea is stimulated directly by vibrations conducted
through the skull bones.
o BC is a measure of Cochlear function only.

- The clinically useful tuning fork tests include:

1. Rinne Test:
- Air conduction (AC) is compared with bone conduction (BC).
- Vibrating tuning fork placed vertically within 1 cm of Opening of
External auditory meatus (AC) then immediately placed on the mastoid
bone (BC).
o (+ve) Rinne Test: (AC > BC)
1. Normal Hearing
2. SNHL
o (-ve) Rinne Test: (BC > AC)
1. CHL (>15-30 dB HL)
2. Severe unilateral SNHL with Crossover (False negative):
ƒ Responds to bone conduction testing which comes
from the opposite normal ear because of
transcranial transmission of sound.
ƒ Correct diagnosis can be made by masking the
Non-test ear while testing for bone conduction.

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2. Weber Test:
- Vibrating tuning fork is placed in Forehead, Vertex or
Maxillary teeth and the sound travels directly to the cochlea
via bone.
- More sensitive than Rinne test (Lateralizes with 5 dB of
conductive hearing loss).
- Normally:
o Heard equally in both ears.
- CHL:
o Lateralized to Diseased ear.
- SNHL:
o Lateralized to Better ear.

1. Tuning fork tests showing:

o Positive Rinne bilaterally
o Weber test referred equally to each ear.
o Dx: Normal Hearing.

2. Tuning fork tests showing:

o Positive Rinne bilaterally.
o Weber test referred to Left ear (Better ear).
o Dx: SNHL in Right ear.

3. Tuning fork tests showing:

o Negative Rinne on Right ear.
o Positive Rinne on Left ear.
o Weber test referred to Right ear (Diseased ear).
o Dx: CHL in Right ear.

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Prediction of Air-Bone gap can be made if tuning forks of 256, 512 and
1024 Hz are used:
- Air-bone gap of > 5 dB:
o Webber lateralized to the affected side
o (+ve) Rinne test for 256, 512 and 1024 Hz.
- Air-bone gap of > 15 dB:
o Webber lateralized to the affected side
o (-ve) Rinne test for 256 Hz.
o (+ve) Rinne test for 512 and 1024 Hz.
- Air-bone gap of > 30 dB:
o Webber lateralized to the affected side
o (-ve) Rinne test for 256 and 512 Hz
o (+ve) Rinne test for 1024 Hz.
- Air-bone gap of > 45 dB:
o Webber lateralized to the affected side
o (-ve) Rinne test for 256, 512 and 1024 Hz.

- Behavioral (Subjective) Audiometric Tests of Hearing:

1. Behavioral Observation Audiometry (BOA): <5 months old.
2. Visual Response Audiometry (VRA): 5 months to 3 years old.
3. Conventional Play Audiometry (CPA): 3 to 5 years old.
4. Pure Tone Audiometry (PTA): >5 years old.
5. Speech Audiometry: >5 years old.

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Behavioral Observation Audiometry (BOA):
- Limited for infants <5 months old.
- BOA is NOT accurate in estimating hearing threshold due to:
o Infant responses are variable and occur at levels above hearing
threshold.
- Physiologic measures (ABR) are necessary for estimation of hearing
threshold in this age group.
- BOA can rule out severe and profound hearing loss only.
- Method:
o Auditory stimuli are introduced via speaker.
o Infant are observed for a response (eye widening, startle, head
turn, cessation of sucking).

Visual Response Audiometry (VRA):

- Limited for children between 5 months to 3 years old.
- VRA is accurate in estimating hearing threshold in cooperative child
using standard audiometric techniques.
- Method:
o Child is trained to turn his head toward auditory stimulus with
visual stimulus (toy animation, flashing light).
o Auditory stimulus is delivered by insert earphones (for ear-
specific response) or by sound field (speakers).

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Conditioned Play Audiometry (CPA):
- Limited for children between 3 to 5 years old.
- CPA is accurate in estimating hearing threshold in cooperative child
using standard audiometric techniques.
- Method:
o Child is conditioned to respond to pure tones by playing a simple
game using toys such as placing a marble in a box.
o Each correct performance of the act is reinforced with
encouragement or reward.

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Pure Tone Audiometry (PTA):
- Most common measurement of hearing sensitivity (threshold).
- Accurate method in estimating hearing threshold for >5 years old.
- Method:
1. Single-frequency sound (pure tone) is produced at selected
sound intensities (db).
2. Presented at different frequencies:
ƒ Octave frequencies:
x 250, 500, 1000, 2000, 4000 and 8000 Hz.
x Standard frequencies tested.
x High-frequency audiometry for frequencies greater
than 8,000 Hz and up to 20,000 Hz is indicated in
patients at risk for ototoxicity.
ƒ Inter-octave frequencies:
x 750, 1500, 3000, and 6000 Hz.
x Tested only if hearing thresholds between two
adjacent octave frequencies are >20 dB.
x Inter-octave hearing loss is a characteristic of
noise-induced cochlear dysfunction.
3. Starting with AC followed by BC:
ƒ Air-Conduction (AC):
x Represents conduction from auricle to cochlea.
x Sound introduced via either:
o Insert earphones:
ƒ Transducer of choice.
ƒ More comfortable.
ƒ Greater interaural attenuation.
o Supra-aural headphones:
ƒ Less comfortable to children
ƒ Less interaural attenuation
x Measures of the function of whole hearing system
(externa, middle and inner ear).
ƒ Bone-Conduction (BC):
x Represents conduction from skull bones to the
inner ear (bypassing external and middle ear).
x Sound introduced via bone oscillator placed over
the mastoid.
x Measure of Cochlear function.
x Not measured at 8000 Hz.
x Should always be better than air conduction.
x Indications of BC testing:
1. Pediatric patients
2. Abnormal AC threshold.
3. Suspecting SCDS.
4. Detect hearing threshold for each frequency:
ƒ Lowest signal intensity (dB) at which the patient
perceives 50% of pure tones at each frequencies.
5. Then charted in Audiogram.

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- Interpretation:
o Type of Hearing Loss:
ƒ Determined by evaluating bone and air conduction
thresholds and the difference between bone and air
conduction (Air-bone gap/ABG).
ƒ ABG measures of the degree of conductive deafness.
ƒ ABG should be at least 10 db.
ƒ Conductive Hearing Loss (CHL):
x Normal bone conduction thresholds.
x Abnormal air conduction thresholds.
x Presence of ABG.
x Maximum CHL is 60 dB which is found in:
o Aural atresia.
o Ossicular chain discontinuity with intact TM.
ƒ Sensorineural Hearing Loss (CHL):
x Abnormal bone and air conduction thresholds.
x No ABG.
ƒ Mixed Hearing Loss (MHL):
x Abnormal bone and air conduction thresholds.
x Presence of ABG.

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o Degree of Hearing Loss:

ƒ Amount of intensity (dB) that has to be raised above the
normal level (0 dB) at each frequency.

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ƒ Pure Tone Average:

x Measures the hearing sensitivity of speech
frequencies in decibels.
x Average AC thresholds of (500, 1000, 2000 Hz).
x Should be within 10 dB of Speech Reception
Threshold (SRT).

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o Masking:
ƒ Audiometric results are valid only when the patient's
responses are caused by stimulation of the test ear.
ƒ Masking is a noise that introduced into non-tested ear to
prevent crossover from the tested ear, whenever sound
stimulation exceeds inter-aural attenuation.
x Narrow band noise is used for Pure-tone signals.
x Wide band noise is used for speech signals.
ƒ Inter-aural attenuation:
x The amount of reduction in sound intensity that
occurs as the signal crosses over the head from
one ear to the other (The amount of sound
intensity needed before crossover occurs).
x No inter-aural attenuation for BC signals and very
faint sound presented to the mastoid of one ear by
BC vibrator can be transmitted through the skull to
either or both inner ears.
x Inter-aural attenuation for AC is higher with insert
ear-phones (70 dB) compared to supra-aural
headphones (40 dB).
ƒ Crossover:
x When the sound that is presented to Tested ear
crosses the head via bone conduction and
perceived by non-tested ear.
x Crossover occurs at:
o 0 dB for Bone Conduction (BC).
o 40 dB for AC with supra-aural headphones.
o 70 dB for AC with insert earphones.
ƒ Indications of Masking:
1. All BC conduction tests.
2. Difference between AC threshold of tested ear and
BC threshold of non-tested ear is:
o > 40 dB with supra-aural headphones.
o > 70 dB with insert earphones.
ƒ Masking Dilemma:
x With effective masking, any signal crossing over to
the ear not being tested is masked by the noise.
x Excess levels of masking noise must be avoided
because the noise can cross back over to the ear
being tested (over-masking).
x Masking dilemma occurs when effective masking to
the non-tested ear can only be done at high level
that causes the noise to cross over to the tested
ear and interferes with accurate estimation of
hearing threshold.
x Occurs in Bilateral severe (50-60 dB) CHL.

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o Special PTA Tests:
ƒ Short Increment Sensitivity Index (SISI Test):
x Test for recruitment phenomenon (abnormal
loudness growth).
x Patients with cochlear SNHL distinguish smaller
changes in intensity of pure tone better than
normal persons, CHL or retrocochlear SNHL.
x SISI test is used to differentiate cochlear from a
retrocochlear SNHL.
x Method:
o Continuous tone is presented 20 dB above
hearing threshold.
o Every 5 seconds, the tone is increased by 1
dB and 20 such blips are presented.
o The patient should count how many times
the tone changes in intensity.
o The score is calculated by multiplying the
number of correct 1 dB increases by 5, which
will provide a percentage.
x Interpretation:
o SISI score is >75% in cochlear SNHL.
o SISI score is <20% in retrocochlear SNHL.

ƒ ToneDecay Test:
x It is a measure of nerve fatigue.
x Used to detect retrocochlear lesions.
x Normally, a person can hear a tone continuously
for 60 seconds.
x In nerve fatigue, he stops hearing earlier.
x Method:
o A tone of 4000 Hz is presented at 5 dB SL
continuously for 60 seconds.
o If patient stops hearing earlier, intensity is
increased by another 5 dB.
o The procedure is continued till patient can
hear the tone continuously for 60 seconds,
or no level exists above the threshold where
tone is audible for full 60 seconds.
o The result is expressed as number of dB of
decay.
x Interpretation:
o Tone decay > 25 dB is diagnostic of a
retrocochlear lesion.

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o Common Audiogram Patterns:

1. Low Frequency SNHL:

o Meniere's disease.

2. High Frequency SNHL:

o Presbycusis
o Ototoxicity

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3. Carhart’s Notch:
o Depression of BC occurs maximum at 2000 Hz.
o Mechanical artifact secondary to stapes fixation and the change
in the normal ossicular resonance, which is around 2000 Hz in
human.
o Occurs in any condition which reduces the inertial vibration of
the stapes footplate:
ƒ Otosclerosis
ƒ Tympanoseclerosis
ƒ Ossicular fixation

4. Acoustic Dip:
o High frequency SNHL at 4000 Hz.
o Noise-induced hearing loss.
o Because natural resonance frequency of EAC is at 3000 Hz but
routine PTA tests only 4000 Hz.

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5. Cookie Bite (U-Shape):
o Hereditary hearing loss.

- Uses of PTA:
1. Measure of threshold of hearing.
2. Predict speech reception threshold.
3. Documentation for future reference.
4. Prescription of hearing aid.
5. Medicolegal purposes.

Test-retest variability in PTA threshold should be ±5 dB

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Speech Audiometry:
- Utilizes spoken voice as a sound stimulus at selected intensities.
- Measures patient's ability to hear and understand speech.
- No need to be done in patient with normal PTA.
- Two parameters are tested:
o Speech Reception Threshold (SRT).
o Speech Discrimination Score (SDS).

- Speech Reception Threshold (SRT):

o Measures hearing threshold for speech.
o Minimum intensity (dB) at which the patient can repeat correctly
50% of Spondees.
o Spondees are 2-syllable words with balanced accents (e.g.
baseball, sunlight, day-dream).
o Normally, SRT should be within 10 dB of PTA average
threshold.
o Indications of masking in SRT:
- Difference between SRT of the tested ear and SRT of non-
tested ear is ≥ 45 dB.
o Recruitment:
- Increasing sound intensity (dB) produces an out-of-
proportion perception of loudness.
- Loud sound which is tolerable in normal ear may grow to
abnormal levels of loudness in the recruiting ear and
becomes intolerable.
- Recruitment causes discomfort within small range of SRT.
- Seen in cochlear SNHL (Meniere's disease, presbycusis).

- Speech Discrimination Score (SDS):

o Measures patient's ability to understand speech.
o Percentage of Phonemes repeated correctly after being
presented at 40 dB SL above the SRT.
o Phoneme is a phonetically balanced (PB) single syllable words
(e.g. pin, sin, day, bus, etc).
o SDS is best in CHL followed by cochlear SNHL followed by
retrocholear SNHL.
o Roll over:
- Paradoxical decrease in SDS with increasing speech
intensity (dB).
- Seen in Retrocochlear hearing loss (Vestibular
schwannoma).

Interpretation of SD:
1. Normal hearing: SD score of 95–100%
2. Conductive hearing loss: SD score 90–100% but at higher intensities.
3. Sensorineural hearing loss: SD score is less. Nerve hearing loss has very poor score in comparison of cochlear
hearing loss.

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- Uses of Speech Audiometry:

1. Measures SRT:
ƒ Correlate SRT with PTA average to diagnose non-organic
(functional) hearing loss.
ƒ
2. Measures SDS:
ƒ Important for HA fitting.
ƒ Differentiate cochlear from a retrocochlear SNHL.

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Impedance Audiometry:
- Battery of Objective tests.
- Providing information about external ear, middle ear, inner ear,
acoustic nerve and brain-stem function.
- Consists of:
1. Tympanometry:
ƒ Compliance of Middle ear system.
ƒ Middle Ear Air Pressure.
ƒ EAC volume.
2. Acoustic (Stapedial) Reflex.
3. Otoacoustic Emissions.

- Immittance Meter:
- Consists of a probe which fits into EAC and has the following channels:
o Oscillator:
ƒ Generates a tone on a frequency of 226 Hz (1000 Hz in
neonates < 6 months).
ƒ Delivered to a probe that is sealed in Ear canal.
o Microphone:
ƒ Pick up and measure sound pressure level reflected from
the tympanic membrane
o Air Pump:
ƒ Measures and changes Air pressure in the ear canal.
o Reflex Signal Generator and Transducers (for Stapedial
Reflex):
ƒ Delivers high-intensity signals to the ear for eliciting
Acoustic Reflexes.
ƒ Transducer is either an earphone on the ear opposite to
the probe ear or a speaker within the probe itself.

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- Tympanometry:
- Indirect test of Middle ear function by transmission/reflection of sound
energy.
- Provides an estimation of:
o Intra-tympanic pressure
o Eustachian tube function
o Tympanic membrane integrity and mobility
o Continuity of the ossicular chain.
- Transmission of sound through Middle-ear mechanism is MAXIMAL
when air pressure is EQUAL on both sides of TM.
- When a sound strikes tympanic membrane, some of sound energy is
absorbed while the rest is reflected.
o Stiff tympanic membrane would reflect more of sound energy
than a compliant one.
- By changing the pressures in a sealed EAC and then measuring the
reflected sound energy, it is possible to find the compliance or stiffness
of the tympano-ossicular system and thus find the healthy or diseased
status of the middle ear.
- Tympanogram:
o Plots compliance changes of TM versus Air pressure in EAC.
o Peak:
ƒ Represents the point of maximum compliance.
ƒ EAC air pressure = Middle ear air pressure
ƒ Normally at 0 daPa.
- Ear Canal Volume:
o Normal value in Children < 1 ml.
o Normal value in Adults < 2 ml.

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Types of Tympanogram:

- Type A:
o Normal middle-ear pressure.
o Normal compliance of TM.
o Features:
ƒ Sharp peak at 0 daPa of Air pressure.
x Normal range between -100 to +50 daPa.
ƒ Height of the peak (compliance) between 0.3-1.5 ml.
o Example:
ƒ Normal patient (Negative predictive value of 95%).

- Type As:
o Normal shape tympanogram.
o Normal middle-ear pressure.
o Reduced compliance of TM.
o Features:
ƒ Sharp peak at 0 daPa of Air pressure.
x Normal range between -100 to +50 daPa.
ƒ Shallow peak < 0.3 ml.
o Examples:
ƒ Ossicular fixation (Otosclerosis, Tympanosclerosis).

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- Type Ad:
o Normal shape tympanogram.
o Normal middle-ear pressure.
o Increased compliance of TM.
o Features:
ƒ Sharp peak at 0 daPa of Air pressure.
x Normal range between -100 to +50 daPa.
ƒ Deep peak > 1.5 ml.
o Examples:
ƒ Ossicular Discontinuity.
ƒ Thin and lax TM.

- Type B:
o Reduced compliance of TM.
o Features:
ƒ Flat or rounded shape tympanogram.
ƒ No change in compliance with Pressure changes.
o Examples:
ƒ High canal volume:
x TM perforation or patent VT.
ƒ Normal canal volume:
x OME (positive predictive value of 90%).
x Thick TM.
ƒ Low canal volume:
x EAC mass (wax, tumor).

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- Type C:
o Normal shape tympanogram.
o Negative middle-ear pressure.
o Features:
ƒ Sharp peak at < -100 daPa of Air pressure.
x Type C1: Peak between -100 to -150 daPa.
x Type C2: Peak between < -150 daPa.
ƒ Regardless the compliance of TM.
o Examples:
ƒ Eustachian Tube Dysfunction.
ƒ Early stages of OME.

- Type D:
o Normal shape tympanogram.
o Normal middle-ear pressure.
o Increased compliance of TM.
o Features:
ƒ Sharp peak at 0 daPa of Air pressure.
x Normal range between -100 to +50 daPa.
ƒ Deep peak > 1.5 ml.
ƒ Notched peak.
o Examples:
ƒ Scarred TM
ƒ Hypermobile TM

Tympanometry for testing Eustachian Tube function:

- Negative or positive pressure (-200 or +200 mm of H2O) is created in
middle ear and person is asked to swallow 5 times in 20 seconds.
- Ability to equilibrate pressure indicates NORMAL ET function.

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Stapedial (Acoustic) Reflex:

- Measure changes in TM compliance caused by contraction of stapedius

muscle.
- Stapedius muscle tendon is attached to head of stapes.
o High intensity loud sound causes BILATERAL contraction of
stapedius muscles (ipsilateral contraction stronger than
contralateral contraction).
o When it contracts, stapedial tendon exerts tension on the
stapes, stiffens the tympano-ossicular chain and reduces energy
transmission through the middle ear.

- Method:
o High intensity sound (70-100 dB HL) above hearing threshold
is introduced in each ear at 500, 1000 and 2000 Hz.
ƒ Sound stimuli should NOT exceed 110 dB HL
ƒ Duration of stimuli should NOT exceed 1 second.
o Ipsilateral (uncrossed) and contralateral (crossed) reflexes are
recorded with sound presented to each ear.
o Normally, Stapedial reflex produces a change TM compliance in
both ears which can be detected on by tympanometry.

- Reflex Arc:
o Ipsilateral high intensity sound (70-100 dB HL)
o Æ Ipsilateral Cochlea
o Æ Ipsilateral CN-VIII
o Æ Ipsilateral Cochlear Nucleus
o Æ Bilateral Superior Olivary Nuclei
o Æ Bilateral CN-VII Nuclei
o Æ Bilateral Stapedius muscles

- Causes of ABSENT Stapedial reflex:

1. Any degree of CHL (Most common cause)
2. Cochlear SNHL > 60 dB
3. Any degree of Retro-cochlear SNHL
4. Brain-stem lesions
5. CN-VII dysfunction proximal to stapedial nerve

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- Two parameters are tested:
o Stapedial Reflex Threshold.
o Stapedial Reflex Decay.

- Stapedial Reflex Threshold:

o Lowest sound intensity level (dB) at which middle ear immitance
change can be detected.
o Normally elicited bilaterally at 70–100 dB SL.
o Allows estimation of degree of cochlear hearing loss.
ƒ Positive stapedial reflex at lower intensities (40-60 dB)
than the usual 70 indicates Recruitment in cochlear SNHL.

- Stapedial Reflex Decay:

o Measures the ability of stapedius muscle to maintain sustained
contraction.
o Method:
ƒ Sound signal is presented 10 dB above stapedial reflex
threshold for 10 seconds.
o Interpretation:
ƒ Normally, the patient will be able to sustained stapedial
reflex.
ƒ Abnormal result is considered if the amplitude of the
reflex decreases ≥ 50% of its initial value within 5
seconds.
x Indicate Retro-cochlear pathology.

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- Uses of Stapedial Reflex:
1. Neonatal Hearing test:
ƒ Not frequently used since ABR and OAEs provide more
information.
2. Diagnose Malingerers:
ƒ No response in PTA.
ƒ Positive Stapedial Reflex.
3. Diagnose cochlear SNHL:
ƒ Positive stapedial reflex at < 70 dB HL
ƒ Indicates Recruitment.
4. Diagnose Retro-cochlear SNHL:
ƒ Abnormal Stapedial Reflex decay.
5. Diagnose Facial nerve lesion proximal to stapedial nerve:
ƒ Absence stapedial reflex without Hearing Loss.
6. Diagnose Brain-stem lesions

Clinical Examples:

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Otoacoustic Emissions (OAEs):
- Low intensity sounds produced by healthy outer hair cells (OHC) of
normal cochlea.
- Evaluate the function of outer hair cells (Cochlea).

- OAEs travels in a reverse direction:

o OHC
o Æ Basilar membrane
o Æ Perilymph
o Æ Oval window
o Æ Ossicles
o Æ TM
o Æ EAC

- Normal OAE indicates:

o Normal cochlea (OHC)
o Normal middle ear system
o Normal external ear system

- Types of OAEs:
o Spontaneous OAEs:
ƒ Presents only in 60% of normal people.
ƒ Doesn't required external stimulus.
ƒ Not used for screening (not sensitive).
o Evoked OAEs:
1. Transiently Evoked OAEs (TEOAEs):
o Presents in all normal ears.
o Evoked by clicks or tone bursts.
o Absent if hearing loss ≥ 30 db.
o Used for Neonatal hearing screening.
2. Distortion Product OAEs (DPOAEs):
o Presents in all normal ears.
o Evoked by simultaneous 2 pure tone frequencies
(F1 and F2).
o Evaluate higher frequencies than TEOAE.
o Absent if hearing loss ≥ 50 db.
o Used for hearing screening due to Ototoxicity and
Noise induced HL.
o Detect Ototoxic effects before conventional PTA but
NOT before HF-PTA.
3. Stimulus-Frequency OAEs:
o Presents in all normal ears.
o Evoked by a continuous pure tone stimulus.

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- Evoked OAEs are Present in:

1. Normal hearing level.
2. Any Hearing Loss < 30 dB in TEOAEs.
3. Any Hearing Loss < 50 dB in DPOAEs.
4. Retro-cochlear SNHL.

- Evoked OAEs are Absent in:

1. EAC pathology (wax impaction or lesions).
2. Middle ear pathology (OME, Otosclerosis).
3. Cochlear SNHL > 30 dB in TEOAEs.
4. Cochlear SNHL > 50 dB in DPOAEs.

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- Uses of Evoked OAEs:

1. Neonate hearing screening (TEOAE).
2. Hearing screening for Ototoxicity and Noise-induced HL
(DPOAE).
3. Diagnosing of Retro-cochlear SNHL:
ƒ SNHL in PTA
ƒ Normal OAE.
4. Diagnosing of Malingerers:
ƒ Hearing loss in PTA
ƒ Normal OAE.

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Auditory Brainstem Response (ABR):
- Also known as:
o Brainstem Auditory Evoked Response (BAER).
o Brainstem Auditory Evoked Potential (BAEP).
- Non-invasive and objective test to record the activity of peripheral and
central auditory systems (from cochlea to cortex) in response to an
auditory signal (clicks or tone bursts).
- Auditory response is not affected by patient conscious level and can be
recorded during sleeping, sedation or coma.
- Method:
o Auditory stimuli (clicks, or tone bursts) are introduced rapidly to
the ear (20-30 times/second).
o These stimuli are detected by surface electrodes placed on the
forehead and earlobe.
o Electrical potentials (waves) are generated in response to these
auditory stimuli.
o Normally, 7 waves are produced within 10 ms after stimuli and
each wave correlates to a specific anatomical location (E-COLI):
ƒ Wave I:
o Originates from Distal CN-VIII.
o Present at birth.
o Stable wave.
o Hallmark for peripheral auditory function.
ƒ Wave II:
o Originates from Proximal CN-VIII.
ƒ Wave III:
o Originates from Cochlear Nucleus.
o Present at birth.
o Stable wave.
ƒ Wave IV:
o Originates from Superior Olivary Complex.
ƒ Wave V:
o Originates from Lateral Lemniscus.
o Largest wave.
o Present at birth.
o Stable wave.
o Used to estimate Hearing threshold.
ƒ Wave VI-VII:
o Originates from Inferior Colliculus.
o Absolute (From stimuli to the wave), inter-wave and inter-aural
latencies of each wave are calculated and compared.
ƒ Normal inter-wave latencies:
x I-III = 2.0 ms
x III-V = 2.0 ms
x I-V = 4.0 ms

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- Common ABR waveform patterns
o Normal:
ƒ Wave I:
o Normal shape.
o Normal latency.
ƒ Normal inter-wave latencies.
ƒ Good morphology.

o CHL:
ƒ Wave I:
o Normal shape.
o Delayed latency.
ƒ Normal inter-wave latencies.
ƒ Good morphology.

o Cochlear SNHL:
ƒ Wave I:
o Small or absent.
o Delayed latency.
ƒ Normal inter-wave latencies.
ƒ Poor morphology.

o Retro-cochlear SNHL:
ƒ Wave I:
o Normal shape.
o Normal latency.
ƒ Delayed inter-aural wave V latency (>0.2 ms).
ƒ Delayed wave I-III latency (>2.0 ms).
ƒ Delayed inter-wave latencies.
ƒ Poor morphology.

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- Uses of ABR:
1. Objective estimation of hearing threshold:
ƒ Method:
x Wave V is observed within 10 dB of PTA.
ƒ Indications:
x Neonates (Hearing screening).
x Suspected malingering.
ƒ Limitation:
x Maximum intensity level to elicit ABR is 80 dB.
x Cannot be used to estimate hearing sensitivity in
severe-to-profound HL.
ƒ Indications:
x High Risk neonates.
x Failed OAE.
2. Diagnosing Retro-cochlear lesions:
ƒ Sensitivity of ABR depends on the size of VS:
x 60-80% sensitive for small VS < 1cm.
x 90% sensitive for medium and large VS.
ƒ Less sensitive than MRI for small tumors resulting in
false-negative results in small intra-canicular tumors.
ƒ Not considered initial diagnostic tool for VS except in
patients with contraindication for MRI (pacemaker).
3. Intra-operative monitoring:
ƒ Used for electrophysiological monitoring of CN-VIII and
auditory brainstem function during hearing preservation
lateral skull base surgeries (vestibular nerve section and
posterior fossa tumor resection).

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Electrocochleography (ECoG):
- Objective test recording the electrical potentials arising in the
peripheral auditory system (cochlea and CN VIII) in response to an
auditory signal (clicks or tone bursts).
- Done under LA or GA.
- Method:
o Surface electrode is placed on the vertex or pinna.
o Probe is placed either in:
ƒ EAC adjacent to TM (non-invasive).
ƒ Promontory via trans-tympanic needle electrode
(invasive).
o Auditory signals (clicks) and the electrical potentials are
recorded.
o Types of recorded electrical potentials:
ƒ Endocochlear Potential:
o DC response generated from Stria vascularis.
o Maintained at + 80 mV by Na-K ATPase.
ƒ Cochlear Microphonic Potential (CM):
o AC response generated from OHC.
ƒ Summation Potential (SP):
o DC response generated from OHC.
ƒ CN-VIII Action Potential (AP):
o All or none response generated from distal CN-VIII.
o Equivalent to ABR wave I.
- Uses of ECoG:
1. Diagnosing Ménière’s disease:
ƒ Tested with electrode placed in the EAC on the TM.
ƒ Normally SP/AP is < 30%.
ƒ SP/AP > 50% indicates Ménière’s disease.
ƒ Sensitivity of 60%.
2. Diagnosing Auditory Neuropathy:
ƒ Absence of wave V on ABR with positive ECoG (CM).
ƒ Useful in determining whether cochlear implantation is
appropriate treatment option or not.
3. Intra-operative monitoring:
ƒ Direct measurement of cochlear and CN-VIII function.

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Approach to Hearing Loss in Adults:

History
- Character of Hearing Loss:
o
o Constant vs. flactuating.
o Progression
o Unilateral vs. bilateral
o High or low tone loss.
o Decreased speech intelligibility
- Contributing Factors:
o Recent infection (fevers, URTI).
o Loud noise exposure.
o Recent trauma (barotrauma, straining, weight lifting, head
injury).
o Exacerbating factors of tinnitus (sleep, exercise, caffeine,
alcohol, stress).
o Previous otologic history (surgery, infections).
o Toxin exposure and medications.
o History of autoimmune disease, hypertension, diabetes, vascular
disorders, TMJ disease, neurologic disease (stroke) and
depression.
o Family history of deafness.
- Associated Symptoms:
o Aural fullness, fevers, vertigo, tinnitus, otalgia, otorrhea, weight
loss, other neurologic complaints

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Physical Exam and Hearing Tests

- Otoscopy/Microscopy:
o Inspection of EAC (cerumen impaction, lesions, masses).
o Inspection of TM (color, thickness, presence of fluid,
myringosclerosis, perforations, lesions).
o Valsalva test (test patency of eustachian tube by having subject
perform Valsalva maneuver and inspect TM for mobility)
- Pneumatic Otoscopy:
o Test mobility of TM with positive and negative pressure.
o Fistula test (Hennebert's sign; positive pressure causes
nystagmus which reverses with negative pressure, may be seen
in perilymph fistulas and syphilitic labyrinthitis).
- Inspection and Palpation:
o Inspect outer ear for lesions, malformations, auricular pits,
scars, edema, swelling, mastoid tenderness, tragal tenderness.
- Complete Head and Neck Exam:
o Cervical lymphadenopathy.
o Neurologic and vestibular exam, bruits.

- Tuning Fork Tests

- Rinne Test:
o Typically uses a 512 Hz (C1 fork) and 1024 Hz tuning forks to
compare air conduction (AC) and bone conduction (BC).
o Strike tuning fork then place within 1 cm of the entrance to the
ear canal (AC) and then immediately place on the mastoid (BC).
o When the tuning fork was better heard by AC then the test is
referred to as Positive (normal ears or most SNHL).
o If BC is perceived louder than AC the test is referred to as
Negative (CHL >15–30 dB HL or severe to profound SNHL with
cross-over)

- Weber Test:
o Typically utilizes a 512 Hz (C1 fork) and 1024 Hz tuning forks.
o Strike tuning fork and place in center of forehead, vertex, or
upper teeth.
o Perceived sound should Normally be heard Centrally (or in
“both ears”).
o Unilateral SNHL should Lateralize to better hearing ear.
o Unilateral CHL should Lateralize to diseased ear.

- Audiometric Tests
- Essential to identify auditory function, CHL vs. SNHL, cochlear vs.
neural dysfunction, central auditory dysfunction, and pseudohypacusis.
o Pure Tone Audiometry (PTA)
o Tympanometry
o Otoacoustic Emissions (OAE)
o Auditory brainstem response (ABR)

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Ancillary Tests

- Imaging:
- Radiographs:
o Special views of the temporal bone (Schuller’s, Stenvere’s,
Towne’s views) have largely been replaced by CT and MRI.
- CT Temporal Bone:
o Indicated to evaluate the complications of suppurative ear
disease, tumors, cholesteatoma, mastoiditis, temporal bone
fracture, or a congenital disorder
- MRI of Brain and Brainstem with Gadolinium:
o Indicated if suspect cerebellopontine angle tumors (vestibular
schwannoma, meningioma), demyelinating lesions (multiple
sclerosis), or petrous apex lesions (cholesterol granuloma)

- Laboratory Studies:
- May be considered for specific circumstances
- CBC:
o May suggest active inflammation or leukemic process
- Lipid Profile:
o High risk of artherosclerotic disease (associated with HL)
- Glucose:
o Screen for diabetes (associated with HL).
- Coagulation Profile:
o Goagulopathies are associated with HL.
- Treponemal Studies:
o Lyme titers and VDRL/FTA-ABS
- Immunological Profiles

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- Hearing Loss:

- Types of hearing problems:

1. Hearing impairment: Both complete and partial loss of the ability to
hear.
2. Deafness: Complete loss of hearing in one or both ears.

- Degree of Hearing Loss:

- WHO recommended the following classification on the basis of pure
tone audiogram taking the average of the thresholds of hearing for
frequencies of 500, 1000 and 2000 Hz.

- There is no apparent impairment of hearing from 0 to 25 dB.

- Disease --> Impairment --> Disability --> Handicap

- When a disease process strikes an organ or a system it causes an
Impairment either in structure or function, but this impairment may
or may not become clinically manifested.
- When impairment affects the ability to perform certain functions in the
range considered normal for that individual it is called Disability.
- The disability further restricts the duties and roles expected from an
individual by society and is called a Handicap.
- To exemplify, injury (disease) to the ear may result in hearing
impairment which, depending on its severity, will affect the individual's
ability to hear and perform certain activities (disability) and will be
termed as handicap by the society.

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- Calculating hearing handicap:
1. Take an audiogram and calculate the average of thresholds of hearing
for frequencies of 500, 1000, 2000 and 3000 Hz (A).
2. Deduct from it 25 dB (as there is no impairment up to 25 dB) (A-25).
3. Multiply it by 1.5 ( (A-25) × 1.5)
4. This is the percentage of hearing impairment for that ear.
5. Similarly calculate the percentage of hearing impairment for the other
ear.

1. Hearing loss does not begin to be handicapping until the PTA at 0.5,
1, 2, and 3 kHz exceeds 25 dB HL
2. Handicap grows at rate of 1.5% per decibel of HL beyond 25 dB
3. Because unilateral deafness is only a mild handicap, the two ears
should not be equally weighted (5:1 favoring better ear)

Monaural Impairment (MI) = 1.5 (PTA – 25)

Binaural Hearing Impairment (BHI) = [5 (MIbetter) + (MIworse)] / 6

- Unilateral Hearing Loss

- Unilateral loss of hearing does not produce a serious handicap or affect
speech.
- It impairs localisation of the sound source, difficulty in discrimination
of speech in the presence of background noise.
- Patient has to take all precautions for the safety of the only hearing
ear.
- Surgeon should be careful when he is called upon to operate on this
only hearing ear.

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Classification of HL:

- Conductive Hearing Loss (CHL):

- Any disease process which interferes with the conduction of sound to
reach cochlea causes conductive hearing loss.
- Lesion may lie in the external ear and tympanic membrane, middle ear
or ossicles up to stapediovestibular joint.

- Characteristics of CHL:
1. Negative Rinne test, BC > AC
2. Weber Lateralised to Poorer ear.
3. Normal absolute bone conduction.
4. Low Frequencies affected more.
5. Audiometry shows bone conduction better than air conduction
with air-bone gap. Greater the air-bone gap, more is the
conductive loss.
6. Loss is not more than 60 dB.
7. Good Speech discrimination.

- Aetiology of CHL:
- Congenital or acquired causes.

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Maximum conductive hearing loss: It is approximately 54 dB and is caused by ossicular

disruption with intact tympanic membrane. Ossicular disruption with perforated tympanic
membrane results in about 38 dB hearing loss.

- Management of CHL:
- Most CHL can be managed by medical or surgical means.
- Consists of:
1. Removal of canal obstructions:
o e.g. impacted wax, foreign body, osteoma or exostosis,
keratotic mass, benign or malignant tumours, meatal atresia.
2. Removal of Middle ear fluid:
o Myringotomy with or without grommet insertion.
3. Removal of Middle ear mass:
o Tympanotomy and removal of small middle ear tumours or
cholesteatoma behind intact tympanic membrane.
4. Stapedectomy:
o In otosclerotic fixation of stapes footplate.
5. Tympanoplasty:
o Repair of perforation, ossicular chain or both.
6. Hearing aid:
o In cases, where surgery is not possible, refused or has failed.

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- Sensorineural Hearing Loss (SNHL):
- Results from lesions of the cochlea, VIIIth nerve or central auditory
pathways.
- May be present at birth (congenital) or start later in life (acquired).

- Characteristics of SNHL:
o Positive Rinne test, air AC > BC.
o Weber Lateralised to Better ear.
o Reduced absolute bone conduction.
o More often involving High frequencies.
o No gap between air and bone conduction curve on audiometry.
o Loss may exceed 60 dB.
o Poor Speech discrimination.
o Difficulty in hearing in the presence of noise.

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- Aetiology of SNHL
- Congenital
o Present at birth and is the result of anomalies of the inner ear or
damage to the hearing apparatus by prenatal or perinatal
factors.
- Acquired
o Appears later in life.
o Genetic or non-genetic causes
o Genetic causes may manifest late (delayed onset) and affect
only the hearing, or be a part of a larger syndrome affecting
other systems of the body as well.

- Common causes of acquired SNHL include:

1. Labyrinthitis
2. Trauma to labyrinth or VIIIth nerve, e.g. fractures of temporal
bone or concussion of labyrinth or ear surgery,
3. Noise-induced hearing loss,
4. Ototoxic drugs,
5. Presbycusis,
6. Meniere's disease,
7. Acoustic neuroma,
8. Sudden hearing loss,
9. Familial progressive SNHL,
10.Systemic disorders, e.g. diabetes, hypothyroidism, kidney
disease, autoimmune disorders, multiple sclerosis, blood
dyscrasias.

- Diagnosis of SNHL:
- History:
o Congenital or acquired
o Stationary or progressive
o Associated with other syndromes or not
o Involvement of other members of the family and possible
aetiologic factors.

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- Severity of Deafness:
o Mild, moderate, severe, profound or total.
o This can be found out on audiometry.
- Type of audiogram:
o Whether loss is high frequency, low frequency, mid-frequency or
flat type.
- Site of lesion:
o i.e. cochlear, retrocochlear or central.
- Radiology:
o CT temporal bone for evidence of bone destruction (congenital
cholesteatoma, glomus tumour, middle ear malignancy or
acoustic neuroma).
- Laboratory tests
o Depend on the Aetiology suspected,
o Blood counts (leukaemia)
o Blood sugar (diabetes),
o Thyroid functions (hypothyroidism),
o Serology for syphilis.
o Kidney function tests, etc.

- Management of SNHL:
- Early detection of SNHL is important as measures can be taken to stop
its progress, reverse it or to start an early rehabilitation program, so
essential for communication.
- Syphilis of the inner ear:
o Treatable with high doses of penicillin and steroids with
improvement in hearing.
- Hearing loss of hypothyroidism:
o Reversed with replacement therapy.
- Serous labyrinthitis:
o Reversed by attention to middle ear infection.
- Meniere's disease:
o Early management prevents further episodes of vertigo and
hearing loss.
- SNHL due to perilymph fistula:
o Corrected surgically by sealing the fistula in the oval or round
window with fat.
- Ototoxic drugs:
o Should be used with care and discontinued if causing hearing
loss.
o It may be possible to regain hearing, total or partial, if the drug
is stopped
- Noise induced hearing loss:
o Prevented from further deterioration if the person is removed
from the noisy surroundings.

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- Non-organic Hearing Loss (NOHL)
- Pseudohypacusis.
- Subjective loss of hearing by a patient with absence of organic
pathology.
1. Malingering:
o There is a motive to claim some compensation for being
exposed to industrial noises, head injury or ototoxic medication.
2. Psychogenic.

- Patient may present with any of the three clinical situations:

o Total hearing loss in both ears
o Total loss in only one ear
o Exaggerated loss in one or both ears.

- Responsibility of the physician is to find out:

o Is the patient malingering?
o If so, what is his actual threshold of hearing?

- Diagnosis:
1. High index of suspicion:
o Patient hesitates or expresses confusion.
o History is inconsistent with hearing loss recorded on tests.
o Makes exaggerated efforts to hear.
o Frequently making requests to repeat the question.
o Placing a cupped hand to the ear.
2. Tuning forks:
o Stenger test:
ƒ Principle is that, if a tone of two intensities, one greater
than the other, is delivered to two ears simultaneously,
only the ear which receives tone of greater intensity will
hear it.
ƒ Take two tuning forks of equal frequency, strike and keep
them say 25 cm from each ear.
ƒ Patient will claim to hear it in the normal ear only.
ƒ Now bring the tuning fork on the side of feigned deafness
to within 8 cm, keeping the tuning fork on the normal
side at the same distance.
ƒ Patient will deny hearing anything even though tuning
fork on normal side is where it could be heard earlier.
ƒ A Normal person or patient with true deafness should
continue to hear on the normal side.
ƒ Patient should be blind-folded during this test.
o Lombard Test:
ƒ Noisy background is gradually introduced below the
subject's recorded response threshold.
ƒ Subject is asked to read aloud.
ƒ Pseudohypacusis is suspected if the volume of the
reader's voice increases as the masking noise increased.

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3. PTA:
o Inconsistent results on repeated PTA:
ƒ Normally, the result of repeat tests are within ±5 dB.
ƒ A variation greater than 15 dB is diagnostic of NOHL.
o Absence of shadow curve:
ƒ Normally, a shadow curve can be obtained while testing
bone conduction, if the healthy ear is not masked.
ƒ This is due to transcranial transmission of sound to the
healthy ear.
ƒ Crossover should be normally occur at 0 dB for BC and 40
db for AC.
ƒ Absence of this curve in a patient complaining of
unilateral deafness is diagnostic of NOHL.
o Stenger test:
ƒ As described previously.
4. Speech Audiometry:
o Inconsistent results on repeated SRT:
ƒ Normally, the result of repeat tests are within ±5 dB.
ƒ A variation greater than 15 dB is diagnostic of NOHL.
o Inconsistency in PTA and SRT:
ƒ Normally, pure tone average (PTA) of frequencies (500,
1000 and 2000 Hz) is within 10 dB of SRT.
ƒ SRT better than PTA by more than 10 dB points to NOHL.
5. Acoustic reflex threshold:
o Normally, stapedial reflex is elicited at 70-100 dB SL and it
should be absent if tests suggests significant hearing loss.
o If patient claims total deafness but the reflex can be elicited, it
indicates NOHL.
6. Auditory Brainstem Response (ABR):
o It is very useful in NOHL and can establish hearing acuity of the
person to within 5-10 dB of actual thresholds.

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- Specific forms of HL:
1. Labyrinthitis:
o Viral labyrinthitis:
- Reach the inner ear by Blood stream.
- Affecting stria vascularis, endolymph and organ of Corti.
- Measles, Mumps and CMV are well documented to cause
labyrinthitis.
- Several other viruses, e.g. rubella, herpes zoster, herpes
simplex, influenza and EBV are clinically known to cause
deafness but direct proof of their invasion of labyrinth is lacking.

o Bacterial labyrinthitis:
- Reach labyrinth through the middle ear (tympanogenic) or
through CSF (meningogenic).
- Sensorineural deafness following meningitis is a well-known
clinical entity.
- Bacteria can invade the labyrinth along nerves, vessels, cochlear
aqueduct or the endolymphatic sac.
- Membranous labyrinth is totally destroyed.

o Syphilitic labyrinthitis:
- SNHL is caused both by congenital and acquired syphilis.
- Congenital syphilis is of two types:
1. Early form: manifesting at the age of 2 years.
2. Late form: manifesting at the age of 8-20 years.
- Syphilitic involvement of the inner ear can cause:
1. Sudden SNHL which may be unilateral or bilateral. The
latter is usually symmetrical in high frequencies or is a flat
type.
2. Meniere's syndrome with episodic vertigo, fluctuating
hearing loss, tinnitus and aural fullness-a picture
simulating Meniere's disease.
3. Hennebert's sign. A positive fistula sign in the absence of a
fistula due to fibrous adhesions between the stapes
footplate and the membranous labyrinth.
4. Tullio phenomenon in which loud sounds produce vertigo.
- Diagnosis of otosyphilis:
- Clinically: (interstitial keratitis, Hutchinson's teeth, saddle nose,
nasal septal perforation and frontal bossing)
- Laboratory tests:
- FTA-ABS and VDRL or RPR tests from CSF.
- Treatment of otosyphilis:
- IV penicillin and steroids.

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2. Familial Progressive SNHL:
- Genetic disorder.
- Progressive degeneration of the cochlea.
- Starting in late childhood or early adult life.
- Bilateral SNHL with flat or basin-shaped ( U-shaped) audiogram.
- Excellent speech discrimination.

3. Ototoxin-Induced Hearing Loss:

- Drugs can damage the inner ear and cause SNHL, tinnitus or vertigo.
- Cochlear Toxicity:
o Pattern:
ƒ Acute cochlear damage may present as Tinnitus.
ƒ Initially, Bilateral HF-SNHL (>4000 Hz).
ƒ Later, Lower speech frequencies are affected.
ƒ If drug is stopped early, further loss may be prevented.
ƒ Partial recovery is possible, but sometimes permanent.
o Time of onset:
ƒ Unpredictable.
ƒ Occurs even after a single dose or after several weeks
after completion of therapy.
- Vestibular Toxicity:
o Mainly with Aminoglycoside antibiotics.
o May appear early with Nystagmus.
o If severe, can lead to dysequilibrium and oscillopsia.

- Common ototoxic agents:

1. Antibiotics (Aminoglycosides, Macrolides, Vancomycin)
2. Anti-neoplastic (Cisplatin)
3. Loop Diuretics
4. Salicylates
5. Antimalarials (Quinine, Chloroquine)

1. Aminoglycoside Antibiotics:
- 2-3%.
- Aminoglycosides are cleared more slowly from inner ear than from
serum and remain in cochlea long time after therapy has ended.
- Results in progression or onset of hearing loss after cessation of the
therapy (delayed toxicity).
- Continuing monitoring up to 6 months after cessation of therapy.
- Vestibular Toxicity:
o 1-11%.
o The most vestibulotoxic of all ototoxic drugs.
o Selectively destroy type I hair cells of the crista ampullaris.
o If administered in large doses, cochleotoxic .
o Primary Vestibulotoxic Drugs:

Gentamicin

Streptomycin
. Tetracycline “ minocycline”

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- Cochlear Toxicity:
o 3-13%
o Irreversible destruction of outer hair cells (OHC) mainly at the
basal turn of the cochlea causing HF-SNHL.
o Inner hair cells are more resistant to injury due to the higher
concentration of the natural antioxidant, glutathione, in IHC and
in the apical turn OHC compared with that in OHC of the basal
turn.
o Primary Cochleotoxic Drugs:
ƒ Neomycin
ƒ Amikacin

- Others:
o Tobramycin:
ƒ Affects vestibular and auditory function equally.
o Netilmicin:
ƒ Least ototoxic aminoglycosides.

- Risk factors:
1. Elderly.
2. Bacteremia.
3. Hepatic or renal dysfunction.
4. Concomitantly other ototoxic drugs.
5. Longer duration of therapy.
6. Increased serum levels (either peak or trough levels)

2. Macrolides (Erythromycin/Azithromycin)
- Sporadic cases of ototoxicity in patients with other risk factors,
including:
o Renal failure
o Hepatic failure
o Doses of more than 4 g/d
o Intravenous administration
- Reversible
- Mainly Cochleotoxic.

3. Vancomycin
- No studies demonstrate conclusive evidence of ototoxicity with
vancomycin alone and in therapeutic doses.
- Reported ototoxicity (Tinnitus), in patients with high serum
concentrations attributed to renal failure or with concomitant

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4. Loop Diuretics:
- 6%.
- Furosemide and Ethacrynic acid
- Block NA and Cl channels in the ascending loop of Henle.
- Ototoxicity is dose-dependant and Reversible in most patients,
although irreversible hearing loss has been reported in patients with
renal failure.
- Mainly cochleotoxic:
o SNHL and Tinnitus.
o Affect Stria vascularis in scala media by changes in potassium
gradients.
- Risk factors:
1. Renal failure
2. Rapid infusion
3. Concomitant aminoglycoside

5. Salicylates:
- Level > 2,700 mg/ day.
- Ototoxicity is reversible.
- Recovery usually occurs 24 to 72 hours after cessation of the drug.
- Mainly cochleotoxic:
o Tinnitus
o Bilateral SNHL particularly affecting higher frequencies.

6. Anti-neoplastic drugs:
- Cisplatin and carboplatin
- Mainly cochleotoxic:
o SNHL and Tinnitus.
o Damage Stria vascularis in scala media and outer hair cell at
basal turn of cochlea.
- Ototoxicity is irreversible.
- Risk increase in patients receiving radiation therapy to H&N.

7. Anti-malaria:
- Quinine and Chloroquin.
- Mainly cochleotoxic:
o SNHL and Tinnitus.
o Quinine toxicity can present as a syndrome known as
Cinchonism
- Reversible.
- Characteristic notch often is present at 4000 Hz.
- If taken during 1st trimester of pregnancy:
o Congenital deafness of child
o Hypoplasia of cochlea

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8. Desferrioxamine:
- Iron-chelating substance used in the treatment of thalassaemic
patients who receive repeated blood transfusions.
- Causes high frequency SNHL.
- Onset is sudden or delayed.
- It is permanent but might be reversible when the drug is discontinued.

9. Topical ear drops:

- Any substance enters ME (through TM perforation) can access IE via
permeability of Round window membrane into perilymph of Scala
Tympani.
- In patients with ear infections, Round window membrane may become
thickened secondary to an immune response and the deposition of
connective tissue, which renders the membrane less permeable and
provide protection from ototoxicity.
- Treatment with drops for prolonged periods of time (>7 days)
increases the risk of ototoxicity.
- Examples:
o Aminoglycoside drops
o Chlorhexidine

- Ototoxicity monitoring for hearing loss

- Baseline Tests:
o Should be done prior to any ototoxic drug administration.
o For Aminoglycosides, tests can be obtained within 72 hours of
starting the treatment.
o Three main approaches:
ƒ PTA:
x Limited to conventional frequency range of 250-
8000 Hz.
x Does not permit the earliest detection of ototoxic
changes in higher frequencies.
ƒ High frequency PTA (HF-PTA):
x Comprises AC threshold testing for frequencies
above 8000 Hz, ranging up to 16 or 20 kHz.
x Permit the earliest detection of ototoxic changes in
higher frequencies before changes become evident
in the conventional range.
x Not available in all institutes.
ƒ Otoacoustic Emission (OAE):
x Responses tend to change before hearing
thresholds in the conventional frequency range, but
not before changes in HFA thresholds.
x Major limitation is that the results are significantly
affected by middle ear pathology such as otitis
media.

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- Follow-up Tests:
o Monitoring should continue during therapy at regular intervals
with at least weekly testing.
o Monitoring should continue for at least 6 months following
cessation of the potentially ototoxic medication.

- Management:
o Prevention.
o Most hearing loss is Irreversible.
o No therapy to reverse ototoxic damage.
o Benefits of ototoxic drugs must be weighed against potential
risks.
o Alternative medications should be considered when appropriate.
o For severe hearing loss, Amplification is the only treatment
option.

ƒ Prevention:
1. Monitor serum drug levels.
2. Monitor renal function.
3. Frequent Hearing evaluation:
x Baseline pre-treatment hearing evaluation.
x Before subsequent antineoplastic drug cycles.
x Periodic evaluation after completion of therapy and up to 6
months post therapy.
4. Avoid noise exposure up to 6 months post therapy.

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4. Noise Trauma:
- Occupational hazard.
- Occupational Safety and Health Administration (OSHA) regulations
exposure equivalent to > 90 dB time-weighted average for 8 hours
requires hearing protection programs (equivalent exposure to 95 dB
for 4 hours, 100 dB for 2 hours, or 130 dB for less than 2 minutes)
- Stapedial reflex is protective for sounds < 2 kHz.
- Stapedial reflex has a latency of 10 ms, thus will not protect cochlea
from unexpected sounds.
- Hearing loss caused by excessive noise can be divided into two
groups:
1. Acoustic trauma:
o Permanent damage to hearing can be caused by a single brief
exposure to very intense sound.
o E.g. an explosion, gunfire or a powerful cracker.
o More severe losses, especially in low frequencies.
o Noise level in rifle or a gun fire may reach 140-170 dB SPL.
o Damage outer hair cells, mechanical damage to organ of Corti
and rupture the Reissner's membrane.
o Concomitantly rupture TM and disrupt ossicular chain.
2. Noise-induced hearing loss (NIHL)
o Chronic exposure to less intense sounds than seen in acoustic
trauma.
o Mainly a hazard of noisy occupations.
o NIHL causes damage to hair cells, starting in the basal turn of
cochlea.
o Outer hair cells are affected before the inner hair cells.
o Rate of hearing loss due to chronic noise exposure is greatest
during the first 10–15 years of exposure and decreases as the
hearing threshold increases (decelerating process).
o This is in contrast to age-related hearing loss, which accelerates
over time (accelerating process)

- Temporary Threshold Shift (TTS):

o Temporary SNHL which occurs immediately after exposure to
noise and resolves within 24 hours.
- Permanent Threshold Shift (PTS):
o Permanent SNHL from noise exposure that does not recover.
o Does not progress after exposure ceased.

- Symptoms of NIHL:
o High pitched tinnitus
o Difficulty in hearing in noisy surroundings
o No difficulty in day to day hearing.
o Hearing impairment becomes clinically apparent to the patient
when the frequencies of 500, 1000 and 2000 Hz (the speech
frequencies) are affected.

1090
Riyadh et al. Notes
170
- Audiogram in NIHL:
o Symmetrical bilateral SNHL.
o Typical notch, at 4 kHz, both for air and bone conduction.
o As the duration of noise exposure increases, the notch deepens
and also widens to involve lower and higher frequencies.
o After about 10 years, loss in the high frequencies tends to
plateau, but the loss continues to broaden gradually into lower
frequencies.
o Notch will disappear as aging changes.

- Factors causing Noise trauma:

o Higher frequency (2000-3000 Hz)
o Higher intensities (dB).
o Continuous.
o Longer duration
o Susceptibility of the individual.
o Pre-existing ear disease.

- Management:
o Preventable.
o Persons who have to work at places where noise is above 85 dB
(A) should have pre-employment and then annual audiograms
for early detection.
o Ear protectors when noise levels exceed 85 dB (Provide
protection up to 35 dB).
o Hearing aids.

1091
 171
OSHA standards

For this reason. expert consensus led OSHA to adopt a 5-dB trading rule: A4- hour
exposure at 95 dBA and a 2-hour exposure at 100 dBA are considered equally as
hazardous as an 8-hour exposure at 90 dBA. Each of these exposures would be
considered to be 90 dBA "time-weighted average" (exposure level that if constant
for 8 hours would be expected to pose the same risk of hearing loss as the briefer
exposure in question). Time-intensity trading ends at 115 dBA: Above this level,
OSHA permits only exposures of less than 1 second. This relationship between
sound level and duration is shown in Table 157.3.

The maximum permissible exposure (without hearing protection) under OSHA

regulations is 90 dBA 1WA. but HCPs must be implemented for all workers whose
exposures exceed 85 dBA 1WA Impulse noise exposure is limited to a 140-dB peak
level.
Riyadh et al. Notes
172
- Sudden Hearing Loss:
- Definition:
o SNHL of >30 dB in 3 consecutive frequencies within 3 days.
- Median age 40-54 years.
- Mostly unilateral.
- Bilateral in 1-5%
- Acute tinnitus accompanies the hearing loss in most cases.
- Vestibular symptoms are present in 25-50% of patients.

- Etiology:
- Divided into categories of
o Idiopathic sudden SNHL (90%):
ƒ Theories includes:
x Viral
x Vascular
x Intracochlear membrane rupture
x Autoimmune.
o Defined causes that must be exclude (10%):
ƒ Infections:
x Mumps, herpes zoster, meningitis, encephalitis,
syphilis, otitis media.
ƒ Trauma:
x Head injury, ear operations, noise trauma,
barotrauma, spontaneous rupture of cochlear
membranes.
x Large vestibular aqueduct syndrome is associated
with SNHL, after minor head trauma.
ƒ Vascular:
x Hemorrhage, embolism or thrombosis of
labyrinthine or cochlear artery or their vasospasm.
x They may be associated with diabetes,
hypertension, polycythaemia, macroglobinaemia or
sickle cell trait.
ƒ Otologic:
x Meniere's disease, Cogan's syndrome,
Perilymphatic Fistula.
ƒ Toxic:
x Ototoxic drugs.
ƒ Neoplastic:
x Acoustic neuroma.
x Responsiveness to steroids is not a reliable
indicator that a retrocochlear lesion is not present.
ƒ Neurologic:
x Multiple sclerosis
ƒ Psychogenic.

1092
Riyadh et al. Notes
173

1093
Riyadh et al. Notes
174
- Evaluation:
o Must be done early; faster treatment improves prognosis.
o Detailed history, physical examination to reach a cause.
o Initial investigations should include:
ƒ Baseline hearing assessment
ƒ MRI or ABR to rule out CPA masses (even if hearing
improved).

o Routine laboratory tests and CT are not recommended in the

initial evaluation of patients with ISSNHL.

- Treatment:
o Oral steroids:
ƒ Mainstay treatment for sudden SNHL.
ƒ Prednisone 1 mg/kg/d (maximal dose is 60 mg/d).
ƒ Full dose for 7-14 days, then taper over similar time
period.
o Intra-tympanic steroids:
ƒ Indications:
x Contraindications to oral steroids.
x Salvage after failed oral steroids.

1094
Riyadh et al. Notes
175
o Hyperbaric oxygen:
ƒ Younger patients respond better to hyperbaric oxygen
therapy (HBOT) than older patients (50-60 years).
ƒ Early HBOT from 2 weeks to 3 months is better than late
HBOT.
ƒ Patients with moderate to severe hearing loss benefit
more from HBOT than those with mild hearing loss.

o Other treatments:
ƒ Should not routinely prescribed.
ƒ Includes:
x Antivirals
x Thrombolytics
x Vasodilators
x Vasoactive substances
x Antioxidants

- Monitoring and prognosis:

o Regular follow-up audiometric evaluation should be done within
6 months of diagnosis.
o 50% showed recovery within a 10-day course of steroid
therapy.
o Final hearing levels is reached by 1 month in 80% of patients
and by 3 months in 97% of patients.
o 30% of patients return to normal hearing.
o 30% of patients end up with profound hearing loss.
o Recovery after treatment:
ƒ Complete:
x PTA within 10 dB of initial hearing level or within
10 dB of the hearing level of the unaffected ear.
ƒ Partial:
x PTA within 50% of initial hearing level or > 10 dB
improvement of hearing level.
ƒ No recovery:
x < 10 dB improvement in hearing level relative to
the initial hearing level.
o Factors for good prognosis:
ƒ Younger patients below 40.
ƒ Minimal hearing loss.
ƒ Low-frequency loss.
ƒ No change in ECoG N1 latency.
o Factors for poor prognosis:
ƒ Advanced age
ƒ Total deafness
ƒ High-frequency loss (down-sloping audiogram)
ƒ Vertigo
ƒ Delay in treatment initiation.
ƒ Associated vascular risk factors

1095
Riyadh et al. Notes
176
- Autoimmune Hearing Loss:
- Most common between ages 20–50 years old.
- Associated with systemic immune diseases (rheumatoid arthritis, lupus
erythematosus, etc), allergy, and vasculitides.

- Pathophysiology:
o may arise from host’s defense from infection causing
autoimmunity.
o Cross reactivity from distant antigens
o Circulating immune complexes affecting circulation in the stria
vascularis

- Symptoms:
o Rapidly progressive (weeks to months) or fluctuating SNHL.
o Bilateral.
o Normal otoscopic exam
o Tinnitus
o Vestibular symptoms in 50%

- Serological Evaluation for Autoimmunity in Hearing Loss::

o CBC,
o ESR
o CRP
o ANA
o RF
o ANCA
o C1q binding test
o Raji cell assay ( for circulating immune complexes).
o Cryoglobulins,
o Complement profiles,
o Lymphocyte transformation test ( exposes patients lymphocytes
to known inner ear antigens to evaluate for reactivity)
o Western blot ( looking for antibodies against 68 kD inner ear
proteins antigen).
o Lymphocyte migration inhibition test (targets type II collagen)

- Management:
o High-dose oral corticosteroid trial for at least 30 days with
audiogram follow-up to assess response.
o If an immunological diagnosis is highly suspected (positive
serology), Immunosuppresive medications (cyclophosphamide,
methotrexate) for nonresponsive cases.
o Consider ajunctive plasmapheresis.

1096
Riyadh et al. Notes
177
- Presbycusis:
- Progressive SNHL associated with physiological aging process in the
ear.
- Most common cause of adult hearing loss.
- Manifests at the age of 65 years.
- 50% of people > 75 years old have hearing impairment.
- Manifests early if there is:
o Hereditary predisposition
o Chronic noise exposure
o Generalised vascular disease.

- Age-Related Changes in the Auditory Systems:

o Cerumen: desquamated epithelium + sebum (from sebaceous
glands) + watery secretions (from modified apocrine sweat
glands)
o Cerumen becomes harder, drier, less likely to be cleared due to
atrophy of modified apocrine sweat glands with aging
o Tragi hairs are coarser, larger, more prominent; leads to
trapping of cerumen
o Arthritic changes in the joints of ossicles do not result in hearing
loss

- Pathophysiology: (PASHA)
1. Mainly, Loss of sensory hair cells due to age-related
degeneration, cumulative noise-induced trauma or cumulative
ototoxin-induced injury over life.
2. Vascular disorder causing atrophy to stria vascularis, loss of
ganglion cells or degeneration of nerve fibers.
3. Stiffing of basilar membrane.

- Four pathological types: (DHINGRA)

1. Sensory:
o Degeneration of the organ of corti.
o Starting at the basal coil and progressing gradually to the apex.
o Higher frequencies are affected.
o Speech discrimination remains good.
2. Neural:
o Degeneration of the cells of spiral ganglion.
o Starting at the basal coil and progressing to the apex.
o Neurons of higher auditory pathways may also be affected.
o Higher frequencies are affected.
o Speech discrimination is poor and out of proportion to the pure
tone loss.

1097
Riyadh et al. Notes
178
3. Strial or metabolic:
o Atrophy of stria vascularis in all turns of cochlea..
o Physical and chemical processes of energy production are
affected.
o Runs in families.
o Audiogram is flat.
o Speech discrimination is good.

4. Cochlear conductive
o Stiffening of the basilar membrane thus affecting its
movements.
o Audiogram is sloping type.

- Symptoms:
o Progressive symmetric SNHL.
o Initially in High frequency (>2000 Hz)
o Downsloping curve in PTA.
o Hearing difficulty in noisy background.
o Hear well in quiet surroundings.
o Sometimes poor speech discrimination.
o Tinnitus
o Recruitment phenomenon is positive and all the sounds
suddenly become intolerable when volume is raised.

- Management:
o Hearing aid.
o Cochlear implant if severe-profound.
o Lessons in speech reading through visual cues.
o Curtailment of smoking and stimulants like tea and coffee may
help to decrease tinnitus.

1098
Riyadh et al. Notes
179
Congenital Hearing Loss:

- Congenital Hearing loss that is present AT birth.

- Types:
o Non-Genetic HL (50%):
ƒ Not caused by genetic mutations.
ƒ Types:
x Inner ear malformations.
x Infections.
x Trauma.
x Ototoxicity.
x Hyperbilirubinemia

o Genetic HL (50%):
ƒ HL presents At or After birth.
ƒ Caused by genetic mutations.
ƒ Classification:
x Non-Syndromic (2/3).
x Syndromic (1/3).
ƒ Mode of inheritance:
x Autosomal Recessive (80%).
x Autosomal Dominant (18%).
x X-linked or Mitochondrial (2%).
ƒ Classic Audiogram pattern is "Cookie Bite" (U-shape).

1099
Riyadh et al. Notes
180
Congenital Non-genetic Hearing Loss:
- Congenital hearing loss not caused by genetic mutations.
- Pre-Natal causes:
o Infections:
ƒ SNHL may be present at birth or later durin childhood.
ƒ Intrauterine infections (TORCHES) are the most common
pre-natal cause of congenital hearing loss.
x TOxoplasmosis, Rubella, Cytomegalovirus, HErpes,
Syphilis.
x CMV is the most common one.
ƒ Examples:
x Congenital Toxoplasmosis:
o Maternal Toxoplasmosis gondii infection
crosses the placenta.
o Clinical picture:
ƒ Congenital SNHL
ƒ Chorioretinitis
ƒ Hydrocephalus
ƒ Intracranial calcifications.

x Congenital Rubella:
o Rare since vaccine and prenatal testing.
o Clinical picture:
ƒ Congenital SNHL
ƒ Cardiac malformation
ƒ Congenital cataracts

x Congenital Cytomegalovirus:
o Spread from maternal primary CMV.
o Most common congenital viral infection.
o Most common viral cause of congenital
SNHL.
o Clinical picture:
ƒ Congenital SNHL (UNILATERAL)
ƒ Mental retardation
ƒ Intracranial calcifications
ƒ Microcephaly
ƒ Retinitis
ƒ Hepatosplenomegaly

x Congenital Herpes:
o HSV-1 and HSV-2.
o Mainly peripartum transmission.
o Rare cause of SNHL.

1100
 Riyadh et al. Notes
181
x Congenital Syphilis:
o Maternal Treponema pallidum infection that
crosses the placenta.
o Clinical picture:
ƒ Congenital SNHL
ƒ Hennebert’s sign
ƒ Interstitial keratitis

- Peri-Natal causes:
o Anoxia
o Prematurity and low birth weight (<1.5 g).
o Birth trauma
o Neonatal jaundice (Hyperbilirubinemia):
ƒ Damages the cochlear nuclei.
o ECMO
o Ototoxic drugs

- Post-Natal causes:
o Infections:
ƒ Meningitis is the most common post-natal cause of
congenital hearing loss.
ƒ Examples:
x Bacterial Meningitis: S. pneumoniae, H. influenzae and N. meningitides are common

o 30% incidence of hearing loss.

o Most commonly after pneumococcal
S. pneumo has highest mortality (19%) and deafness (31%) of the 3 meningitis.
o Pathophysiology:
ƒ Most commonly secondary to
penetration of bacteria and bacterial
toxins via cochlear aqueduct or IAC
contents resulting neuritis of CN-VIII
and/or suppurative labyrinthitis.
ƒ Acute otitis media with direct spread
through labyrinthine may result in
labyrinthitis.
o Dexamethasone was associated with
reduction in severe neurologic sequelae and
hearing loss.
o If a child with meningitis has normal
audiometric studies after first few days of
antibiotic therapy, it is unlikely that
significant SNHL will develop later.
o Some children with initially abnormal hearing
may improve, suggesting a resolving serous
labyrinthitis.
o Late progression of post-meningitic SNHL
after years of stability has been reported.

1101
Riyadh et al. Notes
182
x Mumps:
o Paramyxovirus results in acute viral illness.
Spread from maternal primary CMV.
o Clinical picture:
ƒ Unilateral or bilateral parotitis.
ƒ Congenital SNHL (UNILATERAL).
ƒ Aseptic meningitis
ƒ Encephalitis
ƒ Orchitis
ƒ Mastitis.

1102
Riyadh et al. Notes
183
Congenital Genetic Hearing Loss:
- Congenital hearing loss caused by genetic mutations.
- Types:
o Non-syndromic (2/3):
ƒ More common than syndromic.
ƒ Congenital hearing loss with no other physical or systemic
findings.
ƒ Most commonly due to Connexin Mutations.
o Syndromic (1/3):
ƒ Congenital hearing loss associated with other physical or
systemic findings.
ƒ Most common inheritance pattern is Autosomal
Recessive.
ƒ Examples:
x Usher Syndrome:
o Most common cause of Autosomal Recessive
syndromic HL.
o Most common cause of deaf-blindness.
o Clinical picture:
ƒ Congenital SNHL
ƒ Retinitis pigmentosa
ƒ Mental retardation
ƒ Delayed walking

x Goldenhar Syndrome (Hemifacial Microsomia/

Oculo-Auriculo-Vertebral syndrome):
o Autosomal Recessive syndrome.
o Typically unilateral and on the right side.
o Clinical picture:
ƒ Hemifacial Microsomia.
ƒ Oocular abnormalities.
ƒ Auricular abnormalities (SNHL,
microtia/atresia, Facial nerve
paralysis).
ƒ Vertebral abnormalities (fusion or
absence of cervical vertebrae).

1103
Riyadh et al. Notes
184
x Pendred Syndrome:
o Autosomal Recessive syndrome.
o Associated with Mondini deformity and
enlarged vestibular aqueduct.
o Clinical picture:
ƒ SNHL.
ƒ Euthyroid multinodular goiter

x Treacher Collins Syndrome (Mandibulofacial

Dysostosis):
o Autosomal Dominant syndrome.
o Malformation of the 1st and 2nd branchial
arches.
o Clinical picture:
ƒ Typically normal intelligence.
ƒ Auricular deformities
(microtia/atresia).
ƒ Retro-gnathia
ƒ Macrostomia.
ƒ Lower eyelid coloboma.

x Alport Syndrome:
o X-linked syndrome.
o Mutation in type IV collagen gene.
o Clinical picture:
ƒ SNHL.
ƒ Renal dysplasia/agenesis.
ƒ Progressive nephritis.

1104
Riyadh et al. Notes
185

1105
586 Otolaryngology-Head and Neck Surgery

186
t
Dx: difficult to diagnose by CT since primarily a membranous
defect, definitive diagnosis may only be determined by histologic
examination

Acquired Prenatal (Congenital

Infectious) Hearing Loss
t
JODMVEFT
503$)
JOGFDUJPOT
t
Congenital Toxoplasmosis: delayed onset, progressive SNHL
t
Congenital Rubella: ossicular and cochlear disorders, severe-
profound SNHL, may cause delayed endolymphatic hydrops
t
Congenital Cytomeglalovirus (CMV): most common cause of
OPOHFOFUJD
IFBSJOH
MPTT
_
PG
OFXCPSOT
DPOUSBDU

PG
UIPTF

have symptoms including mild-profound progressive SNHL; new
laws in several US states to provide CMV education to all expectant
mothers and testing opportunities prior to discharge; Dx: PCR
(or serology) preferably <3 weeks of life, Rx: consider 6 months
valganciclovir if test positive
t
Congenital Syphilis: presents at ≤2 years of life or in a delayed form
at 2nd–3rd decade of life, Hennebert’s sign (positive fistula), may
present with endolymphatic hydrops; Dx: FTA-ABS, VDRL

Autosomal Recessive Causes of Hearing Loss

Nonsyndromic Autosomal Recessive Disorders
t
NPSF
DPNNPO
UIBO
TZOESPNJD
t
JEFOUJGJFE
CZ
HFOFUJD
MPDJ
EFOPUFE
XJUI
%'/B- prefix
t
CZ
EFGJOJUJPO
OP
PUIFS
QIZTJDBM
PS
TZTUFNJD
GJOEJOHT
OPOTZOESPNJD

Connexin Mutations
t
NPTU
DPNNPO
DBVTF
PG
IFSFEJUBSZ
OPOTZOESPNJD
IFBSJOH
MPTT
t
DFNB1 BDDPVOUT
GPS
_
PG
DPOHFOJUBM
TFWFSFUPQSPGPVOE

autosomal recessive nonsyndromic hearing loss
t
GJB2 gene (encodes connexin 26 protein, most common) and GJB6
gene (encodes connexin 30) reside at DFNB1 locus
t
35delG is most common connexin 26 mutation.
t
SSx: mild to profound SNHL, usually normal vestibular function

Syndromic Autosomal Recessive Disorders

Usher Syndrome
t
NPTU
DPNNPO
DBVTF
PG
autosomal recessive syndromic hearing loss
CHAPTER 10 Pediatric Otolaryngology 587

187
t
NPTU
DPNNPO
DBVTF
PG
EFBGCMJOEOFTT
EVBM
TFOTPSZ
JNQBJSNFOU
t
Etiology: primarily autosomal recessive (may also be autosomal
dominant or X-linked recessive) results in variable expression
t
Otologic SSx: congenital SNHL, vestibular dysfunction (variable)
t
Other SSx: progressive retinitis pigmentosa (delayed tunnel vision
and blindness), mental retardation, cataracts, delayed walking
t
Types: I: profound congenital SNHL, vestibular areflexia, adolescent-
onset retinitis pigmentosa; II: moderate to severe congenital SNHL,
legally blind by mid-adulthood, normal vestibular function; most
common form; III: progressive SNHL, varied progression of
blindness, progressive vestibular dysfunction
t
Dx: ophthalmology including electroretinography, genetic testing,
vestibular testing showing areflexia

Pendred Syndrome
t
TFDPOE
NPTU
DPNNPO
DBVTF
PG
BVUPTPNBM
SFDFTTJWF
TZOESPNJD
IFBSJOH

loss
t
Etiology: mutation in gene (usually SLC26A4 [PDS]) producing
the pendrin protein resulting in defective iodine metabolism and
organification; SLC26A4 mutation can cause spectrum of disease
ranging from Pendred syndrome to DFNB4 (nonsyndromic hearing
loss)
t
Otologic SSx: mild-profound SNHL (can be mixed HL due to
third window effect), normal middle and outer ear, associated with
Mondini deformity and enlarged vestibular aqueduct, variable
vestibular dysfunction
t
Other SSx: euthyroid multinodular goiter at 8–14 years old
t
Dx: genetic testing, positive perchlorate test (increased iodine release
from thyroid in response to perchlorate)
t
Rx: exogenous thyroid hormone if necessary (suppress goiter growth,
no effect on hearing), thyroidectomy typically not required

Jervell and Lange-Nielsen Syndrome

t
UIJSE
NPTU
DPNNPO
DBVTF
PG
BVUPTPNBM
SFDFTTJWF
TZOESPNJD
IFBSJOH

loss
t
Etiology: genetically heterogeneous with several responsible genes
resulting in severe SNHL and cardiac defects; most commonly
associated with mutations in KCNQ1
t
Otologic SSx: severe to profound bilateral SNHL
t
Other SSx: cardiac abnormalities, recurrent syncope (may be
misdiagnosed as epilepsy), sudden death
t
Dx: ECG (prolonged QT, large T-waves)
t
Rx: β-blockers, defibrillator
588 Otolaryngology-Head and Neck Surgery

188
Goldenhar Syndrome (Oculoauriculovertebral
Spectrum, Hemifacial Microsomia) (see p. 599)

Autosomal Dominant Causes

of Hearing Loss
Nonsyndromic Autosomal Dominant Disorders
t
JEFOUJGJFE
CZ
HFOFUJD
MPDJ
EFOPUFE
XJUI
%'/A-prefix
t
PGUFO
XJMM
IBWF

QBSFOU
XJUI
IFBSJOH
MPTT

Syndromic Autosomal Dominant Disorders

Waardenburg Syndrome
t
NPTU
DPNNPO
DBVTF
PG
BVUPTPNBM
EPNJOBOU
TZOESPNJD
IFBSJOH
MPTT
t
Etiology: mutation in PAX3 gene (in types I and III)
t
Otologic SSx: unilateral or bilateral SNHL, may have vestibular
dysfunction
t
Other SSx: pigmentary abnormalities (heterochromia iridis, white
forelock, patchy skin depigmentation), craniofacial abnormalities
(dystopia canthorum [widely spaced medial canthi, telecanthus],
synophrys [confluent eyebrows], broad nasal root)
t
Types: I: dystopia canthorum, 50% have SNHL; II: no dystopia
canthorum, 80% have SNHL; III: skeletal abnormalities, unilateral
ptosis; IV: Hirschprung disease

Stickler Syndrome (Progressive Arthro-Ophthalmopathy)

t
Etiology: mutation in collagen-producing genes (COL2A1 in Stickler
type 1)
t
Otologic SSx: progressive SNHL (may have mixed HL)
t
Other SSx: ocular abnormalities (myopia, retinal detachment,
cataracts), Marfanoid habitus (tall and thin), arthritic abnormalities
(joint hypermobility, early arthritis), Pierre-Robin sequence

Branchio-Oto-Renal Syndrome (Melnick-Fraser Syndrome)

t
Etiology: mutation most commonly in EYA1 gene (chromosome 8q)
causing abnormal development of branchial arches (including ears)
and kidneys
t
Otologic SSx: pinna deformities; preauricular ear pits, fistulas,
or tags; varied mixed hearing loss with ossicular and cochlear
malformations; may have an associated Mondini deformity or
enlarged vestibular aqueduct
CHAPTER 10 Pediatric Otolaryngology 589

189
t
Other SSx: varied renal abnormalities (agenesis, mild dysplasia);
branchial anomalies; lacrimal duct stenosis
t
Dx: renal involvement may be asymptomatic and only detectable
with pyelography or renal ultrasound

Other Syndromic Autosomal Dominant Disorders

t
Treacher Collins Syndrome (Mandibulofacial Dysostosis) (see
p. 602)
t
Neurofibromatosis 1 and 2 (see p. 410)
t
Apert Syndrome (Acrocephalosyndactyly) (see p. 596)
t
Crouzon Syndrome (Craniofacial Dysostosis) (see pp. 597–598)

X-Linked Causes of Hearing Loss

Nonsyndromic X-Linked Disorders
t
JEFOUJGJFE
CZ
HFOFUJD
MPDJ
EFOPUFE
XJUI
%'/X-prefix

X-Linked Stapes Gusher

t
Etiology: mutation in the POU3F4 gene
t
Otologic SSx: congenital stapes fixation with perilymphatic gusher,
enlarged IAC, mixed HL
t
Other SSx: typically nonsyndromic but may be associated with
choroideremia and mental retardation
t
Dx: CT temporal bone
t
Rx: consider stapes surgery cautiously

Syndromic X-Linked Disorders

Alport Syndrome
t
Etiology: X-linked mutation in type IV collagen gene (COL4A5) >
autosomal recessive or dominant; effects in the glomerular basement
membrane result in progressive renal disease
t
Otologic SSx: slowly progressive SNHL (bilateral degeneration of
organ of Corti and stria), presents in first decade of life
t
Other SSx: renal dysplasia/agenesis, progressive nephritis, ocular
disorders (myopia, cataracts)
t
Dx: urinalysis, renal ultrasound, BUN, serum creatinine,
immunohistochemistry
t
Rx: dialysis and renal transplant

Otopalatodigital Syndrome
t
Etiology: mutation in FLNA gene
590 Otolaryngology-Head and Neck Surgery

190
t
Otologic SSx: ossicular malformation (CHL)
t
Other SSx: craniofacial deformities (supraorbital deformity, flat
midface, small nose, cleft palate, hypertelorism), digital abnormalities
(broad fingers and toes), short stature, mental retardation

Other Hearing Disorders

t
Auditory Neuropathy (see p. 409)
t
Central Auditory Processing Disorder (see p. 409)
t
Sudden Sensorineural Hearing Loss (SSNHL) (see p. 407)
t
Noise-Induced Hearing Loss (see p. 408)
t
Ototoxin-Induced Hearing Loss: (see p. 409)

Otitis Media
Introduction
t
see also pp. 377–387
t
Definition of Acute Otitis Media
1. moderate to severe bulging of the tympanic membrane, or
2. new onset of otorrhea of middle ear origin, or
3. mild bulging of the tympanic membrane and new-onset (<48
hours) ear pain, which can be seen as holding/tugging/rubbing of
the ear, or intense erythema of the tympanic membrane

Medical Treatment of Otitis Media

Acute Otitis Media (AOM) Oral Antibiotic Guideline
(2013 American Academy of Pediatrics)
t
<6 months old with SSx of nonsevere or severe AOM: antibiotics
t
≥6 months old with severe SSx of AOM (moderate–severe otalgia,
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6–23 months old with nonsevere bilateral AOM (mild otalgia <48
IPVST
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t
6–23 months old with nonsevere unilateral AOM: offered antibiotics
or observation with close follow-up; if observing, antibiotics should
be given if SSx worsen or fail to improve within 48–72 hours of onset
t
ǚ24 months old with nonsevere unilateral or bilateral AOM: either
antibiotics or observation
t
First-Line Antibiotics: amoxicillin (80–90 mg/kg/day) if not allergic,
not received antibiotics in <30 days, no purulent conjunctivitis (more
likely non-typeable H influenzae which is resistant), and no history of
recurrent AOM unresponsive to amoxicillin; amoxicillin-clavulanate
Riyadh et al. Notes
191
- Evaluation of HL in Pediatrics:

- History:
- Character of Hearing Loss:
o Age of onset
o Progression of hearing loss
o Communication skills

- Prenatal and Perinatal History:

o Term of delivery
o Birth weight
o Prenatal infections
o Bilirubinemia
o Apgar score
o Maternal drug and Alcohol abuse
o Complications (NICU, ECMO)

- Contributing Factors:
o Syndromic features
o Family history of hearing loss
o History of neurologic disease (seizures).
o History of cardiac disease (Jervell and Lange-Nielsen).
o History of thyroid disease (Pendred).
o History of renal disease (Alport’s).
o History of Sickle cell anemia
o History of Infections (Recurrent OM, Meningitis),
o History of other congenital disease.
o Delayed development (Growth history).
o Surgical history (otologic, neurologic).
o Medications (ototoxic).
o Recent trauma.

- Associated Symptoms:
o Delayed speech development.
o Imbalance or Gait disturbances
o Vision problems
o Other neurologic complaints

- Physical Exam:
- Inspection and Palpation:
o Auricle
o Periauricular pits.
o Facial malformations.

- Otoscopy/Microscopy:
o EAC, TM, Pneumatoscopy.

- Look for Any syndromic features.

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Neonatal Hearing Loss and Speech Development:

- Normal hearing threshold in children is from 0-15 dB.

- Children with profound HL (>90 dB HL) fail to develop speech and
often been termed as deaf-mute.
- They have never heard speech and therefore do not develop it.
- In mild to moderate degrees of HL, speech does develop but is
defective.
- The period from birth to 5 years of life is critical for the development
of speech and language:
o Needs early identification and assessment of hearing loss and
early rehabilitation in infants and children.
o Children whose hearing loss was observed and managed before
6 months of age had higher scores of vocabulary, better
expressive and comprehensive language skills than those
diagnosed and managed after 6 months of age.

- Suspicion of hearing loss in Children:

o Child sleeps through loud noises unperturbed.
o Child fails to startle to loud sound.
o Failure to develop speech at 1-2 years.
o Examine the child every 6 months until the age of 3 years
“critical age for speech/language development” (even if birth
screening is normal).

- Risk Factors for hearing loss in children:

1. Family history of hearing loss.
2. Prenatal intra-uterine infections (TORCHES).
3. Craniofacial Anomalies including those of Pinna and EAC.
4. Birth weight < 1.5 g (3.3 lbs).
5. Hyperbilirubinaemia requiring exchange transfusion.
6. Ototoxic medications.
7. Bacterial meningitis.
8. Apgar score of < 4 at 1 minute < 6 at 5 minutes (Asphyxia).
9. Prolonged stay at NICU or ECMO.
10. Syndromic child.
11. Head trauma.
12. Chemotherapy.

- 50% of infants with marked hearing loss do not have any risk factors.

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Neonatal Hearing Screening:

- Should be done for ALL newborns (preferably) or newborns with high

risk factors for hearing loss.
- Joint Committee on Infant Hearing (JCIH) recommends:
o Universal hearing screening (OAE) by the age of 1 month,
preferably prior to discharge from the hospital.
o Diagnostic evaluation (ABR/OAE/Tympanometry) before the
age of 3 months for newborn who fail initial screening test.
o Intervention for by the age of 6 months.

1. Otoacoustic Emissions (OAE):

o Low cost.
o Non-invasive.
o Measures cochlear (OHC) Function.
o Independent of neural and central auditory system.
o Both DPOAE and TEOAE are used:
ƒ Transient Evoked OAE (TEOAE):
- Presents in all normal ears.
- Evoked by clicks or tone bursts.
- Absent if hearing loss ≥ 30 db.
ƒ Distortion Product OAE (DPOAE):
- Presents in all normal ears.
- Evoked by simultaneous 2 pure tone
frequencies (F1 and F2).
- Evaluate higher frequencies than TEOAE.
- Absent if hearing loss ≥ 50 db.

o Drawbacks if done alone as screening test:

ƒ False Positive results:
- Infant with normal cochlear function fails the
screening test.
- External and Middle ear disorders like EAC
obstruction or OME.
ƒ False Negative results:
- Infant with SNHL passes screening test.
- Normal OHC function.
- IHC disorders or Auditory Neuropathy.

2. Auditory Brainstem Response (ABR):

o Objective means of assessing integrity of Peripheral and
Central Auditory Systems.
o Records activity of CN-VIII and central nervous system’s
response to an Auditory signal.
o Used as hearing screening test for:
1. High Risk neonates.
2. Failed initial screening with OAE.

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Congenital Disorders of External Ear:

o Pre-auricular Skin Tag:

- Accessory auricular remnants.
- Consist of nonfunctional redundant tissue (skin and
fat) found anterior to tragus.
- May contain small pieces of cartilage.
- It may be a duplication of one or several of the
ectodermal hillocks of His.
- Treatment:
ƒ Surgical excision.
ƒ Care should be taken as facial nerve may be very
superficial in young children.

o Pre-auricular Pits and Sinuses:

- Faulty fusion between 1st and 2nd branchial arches
tubercles.
- Depressions or sinuses lined with squamous or
columnar epithelium.
- Commonly seen between tragus and crus of helix.
- Pathway:
ƒ Punctum anterior to Root of Helix.
ƒ Short tract and sinus which ends with an attachment to
perichondrium of Root of Helix.
- Clinical Picture:
ƒ Asymptomatic.
ƒ Discharging a small amount of mucoid discharge.
ƒ Repeated infection.
- Management:
ƒ Complete surgical excision to reduce recurrence.
ƒ Punctum is excised by Elliptical incision.
ƒ Tract and sinus are traced to Perichondrium of
Root of Helix.
ƒ Perichondrium is scored sharply and peeled off
the cartilage.
ƒ Full thickness of cartilage is excised to assure complete
removal in case of recurrence.
ƒ No risk for Facial nerve injury since it is deeper and
inferior to area of dissection.

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- 1st Branchial Cleft Cyst, Sinuses, and Fistula:
o Result from anomalous duplication of EAC.
o May occur between EAC and structures anterior or inferior to
auricle, including neck.
o Classification:
ƒ Work Type I:
o Less common.
o Duplicated EAC.
o Contains ectodermal elements only.
o Begin periauricularly, pass lateral
(superior) to Facial nerve, parallel to
EAC, End as a blind sac near
mesotympanum.

ƒ Work Type II:

o Most common.
o Contains ectodermal and mesodermal
elements.
o Presents near angle of mandible.
o Passes through Parotid, lateral or
medial to Facial nerve, end near or into
EAC.

o Treatment:
ƒ Surgical Excision:
o These anomalies may contain keratin debris that
may become infected which require I & D, but this
is not recommended if it can be avoided.
o The cyst, sinus, or fistula may be gently probed
with a sterile, malleable lacrimal probe or another
suitable instrument to map out its pathway.
o Opening may be gently filled with dye such as
methylene blue prior to excision.
o A rim of tissue around the internal opening is
resected with the specimen and every attempt is
made to excise the tract in toto, leaving none of it
behind.
o If the tract is suspected to course in any relation to
the extratemporal facial nerve, the excision should
be done in a more formal way.
o A modified Blair incision is made, and the parotid is
exposed as is the facial nerve at least from the
stylomastoid foramen to the pes anserinus and
distal branching points, with the use of
intraoperative facial nerve monitoring.
o The cyst, sinus, or fistula must be carefully
dissected from the intact and stimulated facial
nerve.

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196
- Protruding Ear (Bat Ear):
o Auriculocephalic angle >30°
o Poorly developed Antihelix and scapha.
o Large concha.
o Best age for reconstruction is at 5–6
years old when ear is at 85% of adult
size and before the age of social
stigmatization.
ƒ Suture Technique:
- Simple technique.
- Mattress sutures placed
along scapha through a posterior incision to create
an antihelical fold with resulting reduction of
auriculocephalic angle.
- Does not address conchal bowl.
ƒ Cartilage Sculpting Technique:
- Reshaping (scoring, thinning) or splitting of
auricular cartilage to weaken the cartilage surface
to create a convexity for antihelical fold.
ƒ Farrior Technique:
- Combination suture and cartilage sculpting
techniques.
- Removes wedges of cartilage from posterior
surface to allow bending to supplement the
mattress sutures.
ƒ Concha Setback Technique:
- Conchomastoid Suture Technique of Furnas.
- Sutures conchal bowl to mastoid periosteum to
reduce the auriculocephalic angle.

- Cup Ear Deformity:

o Constriction of helix and scapha.
o Surgical correction requires unfurling of helical rim by
dividing the helical-scaphoid cartilage to allow for
expansion followed by redraping of skin over excess
cartilage.

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- Microtia:
o Major auricular malformation.
o Often associated with EAC atresia.
o Degree of auricular malformation correlates with degree of
middle ear deformity.
o Associated inner ear abnormalities are rare.
ƒ Vestibular dysplasia is the most common.
o Usually unilateral with right side is the most common.
o 25% of cases are bilateral.
o M:F ratio of 2.5:1.
o May have syndromic association (eg, hemifacial microsomia).
o Causes:
ƒ Genetic
ƒ Teratogens (vitamin A/isotretinoin, thalidomide)
ƒ Vascular insult
o Classification:
ƒ Grade I:
o Small auricle with all subunits are present.
ƒ Grade II:
o Small auricle with some subunits are severely
underdeveloped or absent.
ƒ Grade III:
o Small remnant of skin and cartilage (Peanut ear)
associated with aural atresia.
ƒ Grade IV (Anotia):
o Complete absence of auricle and lobule associated
with aural atresia.
o Usually forms part of 1st Arch Syndrome.

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199
o Evaluation of patient with Microtia or Aural Atresia:
ƒ H&P:
o Complete H&N examination looking for any other
dysmorphic features.
o Asses facial nerve function:
o Most common anomaly of facial function is a
congenital absence of depressor anguli oris
muscle.
ƒ Hearing Assessment:
o ABR:
o Usually 40–60 dB CHL
o 10–15% have SNHL
ƒ CT Temporal bone:
o Evaluate presence of:
o Middle and Inner ear anomalies.
o Congenital cholestatoma.
o No need to perform CT before age 4 years.
o Should be performed near the time of
operation and must be repeated if done early
after birth before ultimate aural atresia
repair.
o Congenital cholesteatoma usually slow
growing and not happen before this age.

o Treatment Options for Microtia:

1. Surgical Repair:
- Typically at age of 6 years old.
- Timing also influenced by coexisting atresia.
- Types of Grafts:
o Costal Cartilage Autograft:
ƒ Rib is popular cartilage source due to
suitable integrity, sufficient quantity,
and minimal morbidity with harvest.
o Alloplastic Implant:
ƒ Medpor (porous polyethylene) implant.
ƒ Technically easier, does not tolerate
trauma well, risk of extrusion.
o Techniques of Surgical Repair:
o Brent Cartilage Autograft Technique.
o Nagata Cartilage Autograft Technique.

2. Cosmetic Auricular Prosthesis:

o Prosthesis is anchored by magnets (previously
clips) to titanium posts, which are connected to
osseointegrated implants placed in the mastoid
bone, often very realistic.

3. BAHA.

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200
o Brent Cartilage Autograft Technique:
ƒ 4 stages separated by 3 months.
ƒ Some stages may be combined.
ƒ 1st Stage (Auricular Framework):
x Fabrication of the auricular framework from
contralateral costal cartilage.
x Placed in a postauricular subcutaneous pocket (thin
overlying skin as much as possible).

ƒ 2nd Stage (Lobule Transposition):

x Lobule is rotated and often
filleted to receive the end of the
cartilage framework

ƒ 3rd Stage (Framework Elevation):

x Framework is elevated to
achieve projection of the
helical rim.
x Retro-auricular scalp
advancement flap and
STSG used to close the
postauricular defect.

ƒ 4th Stage (Tragus Reconstruction):

x Tragus construction,
conchal excavation,
symmetry adjustments.

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o Nagata Cartilage Autograft Technique:
ƒ 2 stages separated by 6 months.
ƒ 1st Stage:
x Fabrication of the auricular framework from
ipsilateral costal cartilage.
x Lobule Transposition.
x Tragus Reconstruction.

ƒ 2nd Stage:
x Framework is elevated using a crescent-shaped
piece of cartilage to achieve projection of the
helical rim.
x Temporoparietofascial flap is elevated and tunneled
subcutaneously to cover the posterior surface of
the cartilage graft, reconstructed auricle, and the
mastoid surface.
x STSG may also used.

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- Aural Atresia:
o 90% nonsyndromic.
o 10% syndromic.
o 20–30% bilateral
o When it occurs alone, it is due to failure of canalisation of
the ectodermal core that fills the dorsal part of first
branchial cleft.
o The outer meatus, in these cases, is obliterated with
fibrous tissue or bone while the deep meatus and the
tympanic membrane are normal.
o Associations:
ƒ Microtia (55–93%)
ƒ Malformed SCCs (10%).
ƒ Malformed cochlea (5%).
ƒ Cholesteatoma (4–7%).
ƒ Stapes fixation (4%).
o Fusion of malleus/incus is most common middle ear anomaly.
ƒ Footplate is usually normal.
o Otitis media should be treated aggressively to preserve hearing
in the normal contralateral ear.

o Evaluation of patient with Microtia or Aural Atresia:

ƒ H&P:
o Complete H&N examination looking for any other
dysmorphic features.
o Asses facial nerve function:
o Most common anomaly of facial function is a
congenital absence of depressor anguli oris
muscle.
ƒ Hearing Assessment:
o ABR:
o Usually 40–60 dB CHL
o 10–15% have SNHL
ƒ CT Temporal bone:
o Evaluate presence of:
o Middle and Inner ear anomalies.
o Congenital cholestatoma.
o No need to perform CT before age 4 years.
o Should be performed near the time of
operation and must be repeated if done early
after birth before ultimate aural atresia
repair.
o Congenital cholesteatoma usually slow
growing and not happen before this age.

1117
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Riyadh et al. Notes
204
o Treatment Options for Aural Atresia:
1. Conservative Management:
- No immediate medical intervention is necessary in
infant discovered to have unilateral Atresia.
- Early amplification within 1st 3-4 months of life is
essential in infants with bilateral atresia.
o Soft band BAHA must be used.

2. Surgical Management:
- Otologic surgery is generally planned after the
auricular reconstruction surgery if needed.
- Definitive treatment is controversial.
o BAHA vs Surgical repair.
- Candidacy for Surgical Repair Grading Systems:
o Jahrsdoerfer Grading:
ƒ 10-point system based on CT findings.
ƒ Better atresiaplasty candidate if ≥6
points.

o De la Cruz Classification:
ƒ Minor malformations (better surgical
candidate):
x Normal mastoid
pneumatization.
x Normal oval window/footplate.
x Reasonable facial nerve–
footplate relationship.
x Normal inner ear.
ƒ Major malformations (poor surgical
candidate, HA is better option):
x Poor pneumatization.
x Abnormal or absent oval
window/footplate.
x Abnormal facial nerve course.
x abnormalities of inner ear.

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- Surgical approach:
o Anterior approach with drilling over the
atretic EAC.
o Visualizing the Middle ear and assesing the
mobility and integrity of the ossicles.
o Tympanic membrane grafting with fascia
graft.
o Meatoplasty
o STSG over the canal.

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206
Disorders of External Ear:

- External ear can be afflicted by:

1. Congenital disorders
2. Traumatic disorders
3. Inflammatory disorders
4. Non-inflammatory disorders
5. Neoplastic disorders

- Traumatic disorders of External Ear:

o Auricular Hematoma:
- Collection of blood between auricular cartilage and its
perichondrium.
- Etiology:
ƒ Blunt trauma as seen in boxers, wrestlers and
rugby players.
- Complications:
ƒ Perichondritis and Abscess formation:
o Caused by bacterial superinfection.
ƒ Cartilage Necrosis and Cauliflower Ear:
o Extravasated blood may clot and then
organize and causing separation of
cartilage from overlying perichondrium
that supplies its nutrients resulting in
permanent cartilage necrosis and
formation of fibrous tissue in the
overlying skin causing a typical deformity
called Cauliflower Ear.
- Management:
ƒ Aspiration of the hematoma under strict aseptic
precautions and a pressure dressing with dental rolls
(aspiration may need to be repeated).
ƒ If Aspiration is failed, Evacuation with (I&D) and
compression dressing applied (in all concavities) to
prevent reaccumulation, perichondritis, and cauliflower
ear.
ƒ Oral antibiotics while compression dressing in place (1
week).

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207
o Auricular Abscess:
- Collection of abscess between the auricular cartilage
and its perichondrium.
- Etiology:
ƒ Complication of severe or inadequately treated
external ear infections.
ƒ Accidental or surgical trauma to external ear.
o Hematoma.
o Cartilage piercing.
o Exposed cartilage.
o Infected endaural incision.
- Complications:
ƒ Cartilage Necrosis and Cauliflower Ear.
o Cartilage survives only on the blood supply from its
perichondrium.
- Management:
ƒ I&D of abscess under controlled conditions in OR.
o Affected area is cleansed and injected with LA.
o Incision is made in the natural folds.
o Skin flaps are appropriately planned and dissection
taken down to the affected cartilage.
o Abscess should be evacuated and sent for C/S.
o If the cartilage has lost its normal pearly white
appearance, it is necrotic and should be excised.
o Irrigation of the wound with antibiotic irrigation
such as bacitracin (50,000 U of bacitracin dissolved
in 250 mL of normal saline).
o Small drain is placed beneath the flaps and sutured
to the skin.
o Compression dressing applied (in all concavities) to
prevent re-accumulation.
ƒ Aggressive local care
ƒ IV Antibiotics

o Auricular Laceration:
- Repaired as early as possible.
- Perichondrium is stitched with absorbable sutures.
- Special care is taken to prevent stripping of
perichondrium from cartilage for fear of avascular
necrosis.
- Exposed cartilage must be either debrided or covered by
skin to survive.
- Auricular skin often stretches to allow coverage of most
defects.
- If the remaining skin cannot cover the cartilage, the
cartilage should be cut away from the wound margin to
allow overlying skin closure.

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208
- In the case of a linear laceration to the pinna in which the skin
does not approximate, a wedge excision of full thickness triangle
from the antihelix can be used.
ƒ Up to 5 mm of cartilage can be removed without
significant deformity.
ƒ A 1-mm overhang of the skin beyond the cartilage is
recommended to allow skin eversion when closing.
- Skin is closed with fine non-absorbable sutures.
- Broad spectrum antibiotics are given for one week.

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209
o Auricular Avulsion:
- Auricle has a plentiful blood supply and will heal if the
- cartilaginous and soft tissue structures remain even
partly attached.
- Partial avulsions usually survive with at least a 1–2 mm
skin pedicle and primary reattachment should be
considered and it is usually successful.
- Complete auricular avulsion requires attempted
replantation (microvascular techniques), may require a
meatoplasty to avoid external auditory canal stenosis.

o Frostbite:
- Initially, the auricle become pale, hard, and cold due to extreme
vasoconstriction.
- Followed by erythema and edema, bullae formation, necrosis of
skin and subcutaneous tissue, and complete necrosis with loss
of the affected part.
- Treatment:
ƒ Rewarming with moist cotton pledgets at a temperature
of 38-42°C.
ƒ Application of 0.5% silver nitrate soaks for superficial
infection.
ƒ Analgesics for pain as rapid rewarming of frost bitten ear
causes considerable pain.
ƒ Protection of bullae from rupture.
ƒ Systemic antibiotics for deep infection.
ƒ Surgical debridement should wait several months as the
true demarcation between the dead and living tissues
appears quite late.

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Riyadh et al. Notes
210
o Keloid of Auricle:
- Deposition of collagen that extends beyond the limits of the scar
and does not regress over time.
- May follow trauma or piercing of the ear for ornaments.
- Usual sites are the lobule or helix.
- Recurs frequently following single modality treatment, marginal
response to steroid injection when used as a single modality of
treatment.
- Treatment:
ƒ Gentle massage with intralesional
corticosteroid injections (triamcinolone
acetonide) with repeat injections every 3
weeks.
ƒ If no response, may consider excision (with
corticosteroid injections).
ƒ Pressure delivery devices, silicone gel
applications.
ƒ Radiation therapy for severe cases may be
considered but must weigh risk of malignant
transformations.

o Trauma to EAC:
- Minor lacerations:
ƒ Result from Q-tip injury (scratching the ear with hair pins,
needles or match stick) or unskilled instrumentation by
the physician.
ƒ Usually heal without sequelae.
- Major lacerations:
ƒ Result from gun shot wounds, automobile accidents or
fights.
ƒ Condyle of mandible may force through the anterior canal
wall.
ƒ Require careful treatment with the aim is to attain a skin-
lined meatus of adequate diameter.
ƒ Stenosis of the ear canal is a common complication.

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211
- Inflammatory disorders of External Ear:

o Perichondritis and Chondritis:

- Perichondritis is inflammation of external ear perichondrium.
- Chondritis is inflammation of external ear cartilage.
- Etiology:
ƒ Complication of severe or inadequately treated external
ear infections.
ƒ Accidental or surgical trauma to external ear.
o Cartilage piercing.
o Exposed cartilage.
o Hematoma.
o Infected endaural incision.
- Pathogens:
ƒ Pseudomonas Aeruginosa (most common).
ƒ Staph. Aureus.
ƒ Streptococcus
- Clinical Picture:
ƒ Painful, warm, erythematous and edematous
auricle with involvement of EAC.
ƒ Involves all the auricle except lobule.
o Does not contain cartilage.
ƒ Severe itching deep within the canal.
ƒ Skin becomes crusted with squamous debris.
ƒ Involvement of surrounding soft tissues of the
face and neck in severe cases.
- Complications:
ƒ Abscess formation between the cartilage and
perichondrium with necrosis of cartilage and development
of cauliflower ear as the cartilage survives only on the
blood supply from its perichondrium.
- Management:
ƒ Mild cases:
o No abscess formation or involvement of
surrounding soft tissues.
o Thorough ear toilet and debridement.
o Topical anti- Pseudomonas ear drops.
o Oral anti- Pseudomonas antibiotics for 10
days.
ƒ Severe cases:
o Abscess formation
o Involvement of surrounding soft tissues.
o Not responding to oral antibiotics.
o Thorough ear toilet and debridement.
o Culture and sensitivity.
o I&D of Abscess if present in OR.
o Topical anti- Pseudomonas ear drops.
o IV anti- Pseudomonas antibiotics.

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212
o Relapsing Polychondritis (Perichondritis):
- Rare autoimmune disease of unknown etiology.
- Episodic and progressive in nature.
- Involves inflammatory destruction of elastic cartilages.
- Clinical picture:
ƒ Auricular chondritis.
o Entire auricle except its lobule becomes inflamed
and tender.
o External ear canal becomes stenotic.
ƒ Cochlear and vestibular injury (vertigo, hearing loss).
ƒ Respiratory chondritis (laryngeal collapse).
ƒ Nasal chondritis (saddle-nose deformity).
ƒ Polyarthritis (nonerosive, migratory).
ƒ Cardiac valve insufficiency.
- Diagnosis:
ƒ History and physical examination.
ƒ Labs:
o Elevated ESR.
o Elevated IgG.
o Elevated antibodies to type II and type IV collagen
ƒ Biopsy of involved cartilage:
o Perichondrial inflammation with fibrosis.
- Management:
ƒ NSAID.
ƒ Systemic steroids.

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213
o Otitis Externa:
- Spectrum of inflammatory conditions and infections of the EAC.

ƒ Infective Otitis Externa:

x Bacterial:
o Localized Otitis Externa (Fruncles).
o Diffuse Otitis Externa
o Malignant Otitis Externa
x Fungal:
o Otomycosis.
x Viral:
o Herpes Zoster Oticus.
o Otitis Externa Hemorrhagica.

ƒ Reactive Otitis Externa:

x Eczematous Otitis Externa.
x Seborrhoeic Otitis Externa.
x Neurodermatitis.

- Localised Acute Otitis Externa (Furuncle and Carbuncle):

- Staphylococcal infection of hair follicle inside cartilaginous EAC,
most commonly at junction of concha and canal akin.
ƒ Hair are confined only to cartilaginous part of EAC.
- Clinical picture:
ƒ Small well-circumscribed pustule that enlarge to become
furuncle or merge with several similar lesions to form
carbuncle.
ƒ Severe pain and tenderness out of proportion to the size
of the furuncle.
ƒ Movements of the pinna are painful.
ƒ Jaw movements cause pain in the ear.
- In case of recurrent furunculosis:
ƒ Diabetes should be excluded.

Attention paid to patient's nasal vestibules which may
harbor staphylococci and then the infection transferred by
patient's fingers,Periauricular lymph nodes (anterior, posterior and inferior) may get enlarged and tender.
- Treatment:
ƒ In early cases (without abscess formation):
o Consists of medicated ear wick, systemic
antibiotics, analgesics and local heat.
ƒ If abscess has formed:
o Incision and drainage should be done under LA in
addition to medicated ear wick, systemic
antibiotics, analgesics and local heat.

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214
- Acute Otitis Externa (AOE):
- Diffuse bacterial infection of EAC skin caused by a break in
normal skin/cerumen protective barrier in presence of elevated
humidity and temperature (swimmer's ear).

- Pathophysiology:
ƒ Aggressive washing of cerumen or retention of water
results in a more alkalotic EAC and decreased production
of antibacterial agents (eg, lysozyme), which are
permissive for bacterial overgrowth and penetration into
the pilosebaceous unit.
ƒ Begins with itching which is commonly caused by
instrumenting EAC with a cotton swab or fingernail.
ƒ Temporarily relieves itching but allows proliferation of
bacteria in locally macerated skin.
ƒ Itch-scratch cycle.
ƒ Pain.
ƒ EAC Soft tissue swelling.
ƒ Purulent discharge.
ƒ Involvement of Auricle and periauricular soft tissues.

- History:
ƒ Major symptoms of AOE:
o Pain
o Fullness
o Itching
o CHL
ƒ Predisposing factors:
o Auricular instrumentation or trauma
o Swimmers.
o Immunocompromised:
o DM
o HIV
o Radiotherapy

- Physical Examination:
ƒ Edematous, erythematous and tender EAC
ƒ Purulent discharge.
ƒ Tragal tenderness confirms the clinical suspicion.
ƒ Periauricular erythema or cellulitis
ƒ TM perforation may suggest underlying CSOM.

o Evaluate presence of signs and symptoms of Malignant Otitis

Externa:
ƒ Cranial nerve involvement.
ƒ EAC granulation tissue.

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Riyadh et al. Notes
215
- Staging of Otitis Externa:
ƒ Pre-inflammatory stage:
o Edema of stratum corneum due to removal of
protective lipid layer and acid mantle from EAC.
o Obstuction of apopilosebaceous unit.
o Sense of fullness and itching begins.
o Allows invasion of bacteria into the disrupted
epithelial layer.
ƒ Acute inflammatory stage:
o Mild stage:
o Mild redness and edema of EAC skin.
o Small amount of cloudy discharge.

o Moderate stage:
o More pain and itching.
o More redness and edema of EAC skin.
o Thick and profuse exudate.

o Severe stage:
o Sever pain.
o Obliteration EAC lumen obscuring TM.
o Profuse and purulent exudate.
o Extension of involvement beyond EAC:
ƒ Periauricular cellulitis.
ƒ Lymph node enlargment.

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216
ƒ Chronic inflammatory stage:
o Secondary to persistent low-grade infection
or inflammation
o Less pain but more profound itching.
o EAC skin of thick and hypertrophic causing
stenosis and obstruction of EAC in severe
cases.
o Auricle and concha often show secondary
changes such as eczematization,
lichenification, and superficial ulceration.

- Pathogens:
ƒ Pseudomonas Aeruginosa
o Most common, opportunisti infection.
ƒ Staphylococcus
ƒ Other gram-negative bacilli

- Differential diagnosis of Otitis Externa:

ƒ Malignant otitis externa.
ƒ Bullous and granular external otitis
ƒ Perichondritis, chondritis and relapsing polychondritis
ƒ Furunculosis and carbunculosis
ƒ Psoriasis and seborrheic dermatitis
ƒ Carcinoma may present as infection (SCC most common,
can have BCC, melanoma, adenoma or adenoCa, adenoid
cystic).
o Presence of pain in an old previously stable mastoid
cavity is the hallmark of carcinoma and must be
excluded by biopsy and other investigations.

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217
- Management of Otitis Externa:
ƒ Mild stage AOE:
1. Frequent and thorough Ear toilet:
o Most important single factor in treatment.
o All exudate and debris should be
meticulously and gently removed.
o Done by:
ƒ Dry mopping
ƒ Suction clearance
ƒ Irrigation with warm, sterile normal
saline.
2. Antibiotics Drops:
o Anti-Pseudomonas ear drops for 7–10 days
(better if combined with steroids to reduce
the edema as anti-inflammatory).
ƒ Fluoroquinolone:
x Ofloxacin.
x Cipofloxacin.
x Ciprodex (Ciprofloxacin/
Dexamethasone).
ƒ Aminoglycosides (Intact TM):
x Gentamicin.
x Garasone (Gentamicin/
Betamethasone).
x Otosporin (Neomycin/Polymyxin
B/Hydrocortisone).
x Oflox.
3. Oral Pain Analgesia
4. Precautions:
o Avoid EAC trauma or intrumenation.
o Maintain dry ear precautions.

ƒ Moderate stage AOE:

1. Frequent and thorough Ear toilet:
2. Medicated Ear wick:
o Wick soaked in Antibiotic steroid preparation
is inserted in EAC.
o Ichthammol glycerine can be mixed also into
the wick which acts as anti-inflammatory to
reduce pain and edema.
o Wick is kept moist by instilling the same
drops twice or thrice a day.
o Changed daily for 2-3 days when it can be
substituted by ear drops after resolution of
EAC edema.
3. Oral Pain Analgesia
4. Precautions.

1131
Riyadh et al. Notes
218
ƒ Severe stage AOE:
1. Frequent and thorough Ear toilet
2. Medicated Ear wick
3. Oral Antibiotics:
o Used if infection extended beyond EAC.
o Cntinued for 10 to 14 days.
o If no response, Admission with vigorous daily
o local care, repeat culturing, and intravenous
antibiotics are indicated.
ƒ Anti-Pseudomonas antibiotics:
x Ciprofloxadn or levofloxacin
x Caution in children under 12
years old.
ƒ Antistaphylococcal penicillins, or
cephalosporins.
4. Oral Pain Analgesia
5. Precautions.

ƒ Chronic Otitis Externa:

1. Frequent and thorough Ear toilet
2. Ear drops:
o Antibiotic and steroid combination drops.
o DermOtic (fluocinolone 0.01%).
o Acidifying drop composed of equal measures
of vinegar and water.
3. Precautions.
4. Surgical :
o Indicated only if local measures failed to
eradicate the disease and re-establish EAC
lumen.
o Goal of surgery:
ƒ Excise involved canal skin
ƒ Perform wide meatoplasty
ƒ Resurface canal with split-thickness
skin graft.

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219
- Refractory Otitis Externa:
ƒ Take swab from ear discharge for C/S.
ƒ Look for the following:
o Noncompliance or chronic instrumentation of EAC.
o Otomycosis:
o Prolonged antibiotic drops suppress EAC
normal flora and lead to a fungal
superinfection.
o Suspected if:
ƒ Grayish matted discharge
ƒ Precinse of fungal hyphae.
o Managment:
ƒ Ear toilet.
ƒ Canesten (Clotrimazole)
o CSOM:
o Presence of TM perforation with active
discharge from middle ear.
o Presence of cholestatoma.
o Perichondritis.
o Periauricular cellulitis.
ƒ Temporal bone CT scan may add additional information.
ƒ Some patients may need to be admitted for intravenous
antibiotics and daily aural toilet.

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220
- Skull Base Osteomyelitis (SBO) /Necrotizing (Malignant)
Otitis Externa:
- Begins as AOE that does not resolve despite medical therapy.
- Infection extends from EAC into temporal bone, skull base and
jugular foramen resulting in severe progressive osteomyelitis
with multiple cranial nerve palsies.
ƒ "Malignant" otitis externa is a misnomer.
- Caused mainly by Pseudomonas infection.
- Should be the main differential diagnosis of refractory Acute
Otitis Externa in high risk (immunocompromised) patients .
ƒ Diabetics.
ƒ Elderly.
ƒ HIV.
ƒ Radiation exposure.

- Diagnosis Criteria of SBO:

ƒ History:
1. Persistent deep-seated severe otalgia > 1 month.
2. Persistent purulent otorrhea with granulation tissue
for several weeks
3. Immunocompromised state.
4. Cranial nerve involvement
o CN-VII > CN-X > CN-XI.
ƒ Physical Exam:
1. Granulation tissue in inferior aspect of EAC at the
bony-cartilaginous junction.
2. Purulent discharge.
3. Cranial nerve involvement
o CN-VII > CN-X > CN-XI.
ƒ Culture and Biopsy:
1. Almost always P. Aeruginosa.
2. Granulations should be biopsied to rule out
carcinoma or another pathologic entity.
ƒ Imaging:
1. CT scan temporal bone with contrast.
2. MRI with temporal bone with contrast.
3. Bone scans:
o Technetium: used for diagnosis.
o Gallium: used for follow up.

1134
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221

- Imaging of SBO:
ƒ CT scan temporal bone with contrast:
o Initial radiograph to be done.
o Excellent bony detail.
o Define subtle bony changes such as:
ƒ Erosion of anterior canal wall with
involvement of TMJ.
ƒ Erosion of tympanic ring and base of
skull.
o Less precise information about soft tissue.
o Demonstrate soft tissue thickening and
mastoid clouding

1135
Riyadh et al. Notes
222
ƒ MRI temporal bone with contrast:
o Advantages:
o Evaluation of medial extent of disease at the
skull base.
o Evaluation of dural enhancement and
cerebral involvement.
o Disadvantages:
o Imprecise information about bone.
o Changes seen on MRI do not quickly resolve
with clinical improvement.
ƒ MRI is a useful diagnostic tool to
assess the extent of disease but less
useful to follow the clinical course of
SBO.

ƒ Bone Scan:
o Base line Tc-99m and Ga-67 Bone Scan are used
complementary to each other in evaluation of SBO.
o Tc-99m Bone Scan:
o Advantages:
ƒ Used in initial diagnosis of SBO.
ƒ Excellent information about bone
function.
ƒ Evaluates osteoblastic activity as little
as 10% above normal.
ƒ Excellent for localization the extent of
acute or chronic process
o Disadvantages:
ƒ Not used in follow up.
ƒ Stays positive for long period (in acute
and chronic osteomyelitis).
ƒ Positive results in areas of active bone
repair without infection as in trauma.

o Ga-67 Bone Scan:

o Advantages:
ƒ Used in follow up of SBO.
ƒ Gallium is taken up by PMNs and
lights up when active inflammation is
present.
ƒ As treatment progresses, Ga-67 scan
will revert to normal (negative).
o Disadvantages:
ƒ Does Not show the extent of
osteomyelitis.

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Riyadh et al. Notes
223
o Indium-111 Bone scan (New):
o Advantages:
ƒ Better detection of osteomyelitis than
Ga-67 and/or Tc-99m.
ƒ May replace the former two
radionudide modalities in the
evaluation of SBO-suspected patients.

- Differential diagnosis of SBO:

ƒ Severe AOE
ƒ Squamous cell carcinoma
ƒ Glomus jugulare tumor
ƒ Cholesteatoma
ƒ Nasopharyngeal carcinoma
ƒ Hand-Schuller-Christian disease
ƒ Eosinophilic granuloma
ƒ Wegener granulomatosis
ƒ Clival chordoma

- Complication of SBO:
ƒ Cranial neuropathy
ƒ Sinus thrombosis
ƒ Sepsis
ƒ Meningitis
ƒ Intracranial infections
ƒ High mortality (particularly in immunocompromised).

- Poor prognostic factors:

ƒ Facial paralysis
ƒ Polyneuropathy
ƒ Intracranial extension

1137
Riyadh et al. Notes
224
- Management of SBO:
ƒ Medical Management (Mainstay Therapy):
1. Aggressive diabetic control.
2. Local Ear Care:
o Frequent and thorough Ear toilet.
o Medicated Ear wick with Anti-Pseudomonas
Antibiotics drops.
o Water precatuions.
3. Prolonged IV Anti-Pseudomonas Antibiotics:
o IV Ciprofloxacin.
o Used for extended period (6 weeks).
4. Hyperbaric Oxygen:
o Facilitate osteoneogenesis and to promote
repair of diseased bone.
o Useful in the most severe cases due to its
cost and inconvenience.
o Indications:
1. Advanced disease with significant skull
base or intracranial involvement.
2. Recurrent disease
3. Infections refractory to antibiotic
treatment.

ƒ If the ear remains purulent despite adequate

intravenous antibiosis and local care:
x Repeat cultures should be taken to look for the
emergence of a resistant organism.

ƒ Surgical Management:
o Controversial.
o Surgical debridement of devitalized tissue and bone
should be done judiciously.
o Radical resections have been abandoned in favor of
prolonged intensive medical therapy.
o Indicated only for severe disease not responding to
aggressive medical therapy.
o Surgical management includes:
ƒ Excision of granulations
ƒ Middle ear exploration
ƒ Mastoidectomy
ƒ CN-VII decompression
ƒ Temporal bone resection

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225

1139
Riyadh et al. Notes
226
- Otomycosis:
- Fungal infection of EAC skin.
- Primary fungal infection occurs mainly in immunocompromised
patients including diabetics.
- Secondary otomycosis occurs in patients with chronic bacterial
infection in which prolonged antibiotic drops suppress EAC
normal flora and lead to a fungal super-infection.
- Basic growth requirements for fungal infections:
1. Moisture
2. Warmth
3. Darkness
- Most common fungal pathogens:
ƒ Aspergillus:
o Most common pathogens.
o Mainly Aspergillus Niger.
o If aural culture should grow Aspergillus Fumigatus
or Aspergillus Flavus, one would be concerned
about a more invasive infection.
ƒ Candida Albicans:
o 10% of otitis externa.
- Clinical picture:
ƒ Pruritus:
o Intense itching is the primary clinical complaint.
ƒ Otalgia.
ƒ Otorrhea.
- Diagnosis:
ƒ Examination under microscope:
o Dotted white, black, or gray
membrane over EAC.
o Aspergillus produces distinct small
black conidiophores on top of fluffy
white filamentous hyphae.
ƒ Culture and sensitivity.
- Treatment:
ƒ Thorough ear toilet:
o First and absolutely most important step.
o Removal of all discharge and epithelial debris.
ƒ Precautions:
o Avoid EAC trauma or intrumenation.
o Maintain dry ear precautions.
ƒ Antifungal topical drops (Canesten/Clotrimazole):
o Most effective and widely used topical azole.
o It has antibacterial and antifungal effect.
o Painful in the presence of a TM perforation or
patent ventilation tube.
o No reports of ototoxicity.
ƒ Medicated Ear wick:
o In severe cases.

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227
- Herpes Zoster Oticus:
- Occurs as primary infection or reactivation of latent varicella-
zoster virus (VZV) that has remained dormant within sensory
ganglia (commonly the geniculate ganglion)
of the facial nerve.

- Risk factors for the reactivation:

ƒ Decrease immunity.
ƒ Physical and emotional stress.

- Clinical picture:
ƒ Burning pain
ƒ Localized headache
ƒ Coetaneous vesicular eruption of EAC and pinna.
o Appear unilaterally in a dermatomic distribution.
ƒ Involvement of CN-VII may produce paresis or paralysis
(Ramsay Hunt syndrome):
o Accounts for 10% of all facial paralyses.
o More severe paralysis and worse prognosis than
Bell palsy.
ƒ Involvement of CN-VIII may produce SNHL and vertigo.

- Complications of HZ oticus:
ƒ Post-herpetic neuralgia
ƒ Residual paralysis
ƒ Herpes zoster encephalitis

- Treatment of HZ oticus:
ƒ Supportive Measures.
o Warm compresses
o Good analgesics
ƒ Anti-viral:
o Acyclovir, Famciclovir, Valacyclovir
o Early administration (< 72 h) increases rate of
facial nerve function recovery.
o Decreases severity of post-herpetic neuralgia.
ƒ Corticosteroids:
o Used to relieve acute pain, decrease vertigo, and
limit the occurrence of postherpetic neuralgia.
o Treatment with acyclovir and prednisone has more
effective return to facial nerve function and
prevention of nerve degeneration.

1141
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228
- Bullous Otitis Externa:
- Characterized by formation of
serous/hemorrhagic bullae on epithelial surface
of tympanic membrane and deep meatus.
- If it involves the tympanic membrane only, it is
called Bullous Myringitis.
- Etiology:
ƒ Probably viral in origin.
ƒ Caused by same viruses or bacteria that
cause middle ear infections.
ƒ Despite common belief, Mycoplasma
pneumoniae is an extremely rare causative agent.
- Clinical picture:
ƒ Sudden severe pain in the ear.
ƒ Blood-stained discharge when the bullae rupture.
ƒ Hearing loss.
- Treatment:
ƒ Analgesics is directed to give relief from pain.
ƒ Antibiotics are given for secondary infection of the ear
canal if the bulla has ruptured.
ƒ Severity of pain may warrant decompression of tense
bullae with a sterile straight needle.

- Eczematous Otitis Externa:

- Hypersensitivity to infective organisms or topical ear drops.
- Marked by intense irritation, vesicle formation, oozing and
crusting in the canal.
- Treatment is withdrawal of topical antibiotic causing sensitivity,
and application of steroid cream.

- Seborrhoeic Otitis Externa:

- Associated with seborrhoeic dermatitis of the scalp.
- Itching is the main complaint.
- Greasy yellow scales are seen in the external canal,
over the lobule and postauricular sulcus.
- Treatment consists of ear toilet, application of a
cream containing salicylic acid and sulphur, and
attention to the scalp for seborrhoea.

- Neurodermatitis:
- Compulsive scratching due to psychological factors.
- Patient's main complaint is intense itching.
- Otitis externa of bacterial type may follow infection of raw area
left by scratching.
- Treatment is sympathetic psychotherapy and meant for any
secondary infection.
- Ear pack and bandage to the ear are helpful to prevent
compulsive scratching.

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229
o Aural Polyps:
- Inflammatory tissue of EAC or middle ear mucosa.
- Etiology:
ƒ CSOM
ƒ Cholestatoma
ƒ Foreign body reaction to ventilation tube.
ƒ Malignant tumors
- Clinical picture:
ƒ Well-circumscribed, soft, fleshy mass.
ƒ Painless.
ƒ Symptoms related to EAC obstruction or
secondary infection.
- Diagnosis:
ƒ History and physical examination.
ƒ CT/MRI with contrast:
o Precisely define the anatomic site of origin.
o Indicated if there is any suspicion that:
o It could be attached to a deeper structure,
such as facial nerve, stapes footplate, and a
dehiscence of the vestibular labyrinth.
o It could be a herniation of meninges and/ or
brain (meningoencephalocele,
encephalocele).

- Treatment:
ƒ Topical steroid/antibiotic drops.
ƒ Aural polyp excisional biopsy:
o Must be done with caution and should never be
avulsed.
o Inflammatory polyp will easily yield to gentle
manipulation.
o Another underlying disease process may be more
resistant and should never be removed with force.
ƒ Middle ear exploration:
o In patients with aural polyp secondary to
cholesatatoma.

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230
- Non-Inflammatory disorders of External Ear:

o Chondrodermatitis nodularis chronica (Winkler nodule):

- Benign inflammatory condition.
- Caused by breakdown of elastic fibers due to chronic sun
exposure.
- Clinical picture:
ƒ Most commonly located at free rim of
helix or on the antihelix.
ƒ Papules or nodules painful to touch or
pressure and patient is unable to sleep
on the affected side.
o Distinguishes it from other
painless dermatologic lesions
such as:
o Senile keratosis
o Keratoacanthoma
o Cutaneous hom
o Skin cancer (squamous or basal cell).
ƒ There is a chronic inflammatory infiltration of the
perichondrium with focal degeneration or deformity of the
underlying cartilage.
- Treatment:
ƒ Wide excision with deep shave of the underlying cartilage.
ƒ Intralesional injections with steroid.

o Keratoacanthoma:
- Self-healing basal cell carcinoma.
- Caused by actinic (sun) exposure.
- May arise from hair follicles.
- Clinical picture:
ƒ Rapidly growing, raised, and circular with a
central crater usually containing a keratin
plug.
- Diagnosis:
ƒ Excisional biopsy for definitive diagnosis.
- Treatment:
ƒ Observation if the lesion is undergoing
gradual resolution.

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231
o Keratosis Obturans:
- Acute upon chronic condition of external ear.
- Accumulation of desquamated keratinous material in
bony EAC leading to secondary, acute infection.
- Occurs bilaterally in young patients with
bronchiectasis and chronic sinusitis.
- Occurs also in elderly patients in a nursing home in
which care of the ear is neglected.
- Keratosis Obturans is reversible condition.
ƒ Once completely cleaned and topically
medicated, the ear will gradually revert back toward a
healthy appearance.
ƒ Different than External canal cholesteatoma which is
irreversible condition.
- Etiology:
ƒ Abnormal epithelial migration and/or hyperplastic
epithelium with increased desquamation.
o Normally, epithelium from surface of tympanic
membrane migrates onto the posterior meatal wall.
- Clinical picture:
ƒ Otorrhea with keratin debris inside EAC.
ƒ Severe otalgia.
ƒ CHL
ƒ Widening of bony EAC with ulceration and granuloma
formation.
ƒ In advanced cases, EAC stenosis occurs in response to
chronic irritation and infection.
- Diagnosis:
ƒ History and physical examination.
ƒ CT scan shows diffuse widening of the EAC.
ƒ Pathologic examination of keratin materials.
- Treatment:
ƒ Regular thorough debridement of EAC under microscope
in the clinic.
o Extremely painful to clean and pain must be
eliminated prior to aural toilet.
o May require a four-quadrant block of EAC
with LA or may be done in OR under GA.
ƒ Antibiotics/steroid drops if infected.
ƒ Routine use of acetic acid solution or hydrogen peroxide
solution may reduce accumulation.
ƒ Canaloplasty with skin graft for recalcitrant cases.

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232
o External Canal Cholesteatoma:
- Localized ulceration in skin of bony EAC with
infection and sequestration of the underlying
exposed tympanic bone.
- Caused by blockage of EAC permitting
accumulation of epithelial debris causing bone
remodeling from pressure of the keratin.
- Usually unilateral and affects older patients.
- External Canal Cholesteatoma is irreversible
condition.
ƒ It does not revert back toward a normal state once
obstruction and local infection have been relieved and
treated.
ƒ Different than Keratosis Obturans which is reversible
condition.
- External Canal Cholesteatoma has many features in common
with primary acquired cholesteatoma including active matrix
that elaborates keratin debris which can locally erode bone and
soft tissue.
- Etiology:
ƒ Acquired:
o Surgery
o Trauma
o Acquired stenosis
o Chronic inflammation
ƒ Spontaneous
- Clinical picture:
ƒ Tympanic ring especially its anterior and inferior aspects
is a favored site for External Canal Cholesteatoma.
ƒ Persistent dull otalgia.
ƒ Otorrhea with keratin debris inside EAC.
ƒ CHL
- Diagnosis:
ƒ History and physical examination.
ƒ CT scan shows focal erosion.
- Treatment:
ƒ External canal cholesteatoma is mainly managed
medically and not surgically.
o Regular thorough debridement of EAC under
microscope in the clinic.
ƒ There is really very little need for surgery in even the
most advanced cases.
o Meatoplasty may be indicated to facilitate aural
toilet.
o Canaloplasty with skin graft for recalcitrant cases.

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233
o Cerumen impaction:
- Normally, small amount of wax is secreted which
dries up and later expelled from the meatus by
movements of the jaw.
- Wax is composed of:
ƒ Sebaceous glands secretions
ƒ Ceruminous glands secretions
ƒ Hair
ƒ Desquamated epithelial debris
ƒ Keratin
ƒ Dirt.
- Risk factors of cerumen impaction:
ƒ Higher activity of ceruminous glands
ƒ Narrow and tortuous ear canal
ƒ Stiff hair
ƒ Obstructive lesion of the canal.
ƒ Using Q-tips
ƒ Hearing aids
ƒ Earplugs
- Clinical picture:
ƒ Onset of these symptoms may be sudden when water
enters the ear canal during bathing or swimming and the
wax swells up.
o CHL if >95% of canal is occluded
o Fullness
o Tinnitus
o Autophony
o Vertigo (rarely)
- Treatment:
ƒ Manual removal under magnification.
ƒ Techniques:
o Instrumental manipulation.
o Low-pressure irrigation if no perforation
o Cerumen-softening agents:
o Waxsol (Docusate Sodium)
o Sodium Bicarbonate
o Mineral oil

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234
o EAC foreign body (FB):
- Classified into:
ƒ Living (Organic):
o Flying or crawling insects.
o Cause intense irritation and pain.
o Patient is bothered by insect's
movement.
o Insects must be killed and then
removed.
o Lidocaine or mineral oil.
ƒ Non-living (Inorganic):
o Piece of paper or sponge, grain seeds
(rice, wheat, maize), batteries, slate
pencil, piece of chalk or metallic ball
bearings, overlooked cotton swab.
o Batteries
o Vegetable foreign bodies tend to swell
up with time and get tightly impacted
in the ear canal or may even
suppurate.
- Treatment:
ƒ Manual removal under magnification.
ƒ Batteries must be removed as soon as possible without
delay because they may cause extensive chemical burns
to the EAC.
ƒ For uncooperative patient or impacted FB with failed
attempts of removal, best done in OR under GA.
ƒ Techniques:
o Soft and irregular foreign bodies like a piece of
paper, swab or a piece of sponge can be removed
with fine crocodile forceps.
o Most of the seed grains and smooth objects can be
removed with syringing.
o Smooth and hard objects like steel ball bearing
should not be grasped with forceps as they tend to
move inwards and may injure the tympanic
membrane and best removed with a blunt wax
hook.
o Postaural approach is used to FB impacted in deep
meatus, medial to the isthmus or those which have
been pushed into the middle ear.

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235
- Neoplastic disorders of External Ear:

o EAC Exostoses (Surfer's ear):

- Benign, slowly growing, broad-based bony growth of deep EAC.
- Not true neoplasms.
ƒ Localized bony calluses or hyperostoses arising from the
medial surface of tympanic bone.
- Males are affected three times more than females.
ƒ 70% of exostoses is reported in surfing population.
- Etiology:
ƒ Acquired, develop as a reactive phenomenon
(Refrigeration Periostitis) due to chronic exposure of EAC
bone to cold water or air in activities such as swimming,
surfing, skiing, or boating.
o Cold induce vasoconstriction of deep EAC, followed
by a reactive hyperaemia and a stimulation of
periosteum lining the medial surface of the
tympanic bone which lays down consecutive layers
of subperiosteal bone.
- Clinical picture:
ƒ Bilateral, multiple, sessile bony lesion of deep EAC.
ƒ Covered by normal deep canal skin.
ƒ Found more medial than Ostemoa.
ƒ Usually asymptomatic, unless it is large or multiple
causing trapping of wax and keratin debris in the deep
meatus producing:
o CHL
o Recurrent otitis externa
o Acquired external canal cholesteatoma
- Diagnosis:
ƒ History and physical examination.
ƒ CT scan:
o Broad based bony overgrowth with no deep
extension (no stalk).
o More dense than ostemoas.

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236

1150
Riyadh et al. Notes
237
o EAC Osteoma:
- True benign bony neoplasm.
- Arises from tympanic bone at tympano-squamous or tympano-
mastoid suture lines.
- Etiology:
ƒ Unknown.
ƒ Does not develop as a reactive phenomenon.
o Not related to cold water or air exposure.
- Clinical picture:
ƒ Unilateral, solitary, pedunculated bony lesion of EAC.
ƒ Covered by normal deep canal skin.
ƒ Found more lateral than Exostoses.
ƒ Usually asymptomatic, unless it is large trapping of wax
and keratin debris in the deep meatus producing:
o CHL
o Recurrent otitis externa
o Acquired external canal cholesteatoma
- Diagnosis:
ƒ History and physical examination.
ƒ CT scan:
o Osteoma is more heterogeneous with areas of
cancellous bone.
o Less dense than exostosis.
o Stalk leading to the osteoma can be seen as well.

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238

1152
Riyadh et al. Notes
239
- Treatment of Exostoses and Osteoma:
ƒ Observation:
o For small, asymptomatic lesions and when most of
TM is visible.
ƒ Surgery:
o Indications:
1. Symptomatic patients
ƒ CHL
ƒ Recurrent otitis externa
ƒ External canal choestatoma.
2. To allow proper HA fitting.
o Surgical approach:
o Trans-canal shaving with facial nerve
monitoring and preservation of the skin:
ƒ The goal is to be able to see most of
TM and to enlarge the EAC enough to
hold an ITC (in the canal) HA mold.
o Post-auricular approach is used sometimes.
o Surgical complications:
o TMJ violation.
o Canal stenosis
o SNHL
o TM perforation
o Facial nerve injury

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240
o Malignant Neoplasms of External Ear:
- Cancers of auricle and EAC include more commonly:
ƒ Basal cell carcinoma
ƒ Squamous cell carcinoma
ƒ Melanoma (melanotic and amelanotic).
- In majority of skin cancers, malignancy is result of chronic sun
(actinic) exposure.
- Risk factors:
ƒ Individuals with fair skin, light hair and blue eyes.
ƒ Individuals with genetic defects of skin repair.
ƒ High amount and long sun exposure.
ƒ Tight-fitting ear molds leading to chronic irritation of the
EAC
- Treatment:
ƒ Many malignancies of the auricle may be treated with
local, chemo-controlled excision with the defect repaired
via skin grafting or local advancement flaps.

1154
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241
Disorders of Tympanic Membrane:

- Disorders of TM may be primary or secondary to conditions affecting

external ear, middle ear or eustachian tube.
- Normal tympanic membrane:
o Shiny and pearly-grey in color.
o Semit-ransparent and some middle ear structures can be seen.
o Mobile when tested with pneumatic otoscope.
o Concave on its lateral surface, more marked at the tip of
malleus (umbo).
o Bright cone of light can be seen in Antero-inferior quadrant.
o Attic area lies above lateral process of malleus and is slightly
pinkish.

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Riyadh et al. Notes
242
o Retracted Tympanic Membrane and Retraction Pockets:
- Collapsing of a part or entire TM into middle ear.
- Occurs as a result of negative intratympanic pressure when the
eustachian tube is blocked.
- Prolonged dysfunction of Eustachian tube and excessive
negative pressure in the middle ear leads to atrophic changes in
middle, fibrous layer of tympanic membrane and to
development of localized or generalized TM atelectasis.

- Complications of Retracted TM:

1. Cholestatoma:
o Deep retraction pocket impairs the normal
migration of epithelial cells leading to accumulate
keratin debris and formation of cholesteatoma.
2. Ossicular Necrosis:
o Progression of TM retraction causes the atrophic
membrane to drape over incus and stapes leading
to necrosis of these ossicles.
o Commonest ossicle eroded being the long process
of incus.
3. Adhesive Otitis Media:
o Prolonged TM retraction forms adhesions with the
surrounded structures, which make changes
irreversible.

- Most common sites of retraction pockets:

ƒ Pars flaccida:
o Retraction pocket development is quicker, followed
by quick bone absorption, and faster formation of
cholesteatoma due to lack of fibrous layer of TM.
o Management should be more aggressive.
ƒ Postero-superior parts of Pars tensa.

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243
- Tos Classification for Pars Flaccida Retractions:
ƒ Tos I:
o Slight retraction of Pars flaccida that is not in
contact with malleus head.
ƒ Tos II:
o Retraction of Pars flaccida that is in contact with
malleus head.
o Full extent of retraction pocket can be clearly seen.
ƒ Tos III:
o Severe retraction of Pars flaccida that is in contact
with malleus head.
o Limited erosion of outer attic wall (scutum).
o Part of retraction pocket may be hidden.
ƒ Tos IV:
o Severe retraction of Pars flaccida that is in contact
with malleus head.
o Severe erosion of outer attic wall (scutum).
o Extent of retraction pocket cannot be clearly seen.

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Riyadh et al. Notes
244
- Sadé Classification for Pars Tensa Retractions:
ƒ Sadé I:
o Slight retraction of Pars tensa.
ƒ Sadé II:
o Severe retraction of Pars tensa with contact into
incus or stapes.
ƒ Sadé III:
o Middle ear atelectasis.
o Severe retraction of Pars tensa with contact into
promontory, but mobile with the Valsalva or
Toynbee maneuvers.
ƒ Sadé IV:
o Adhesive otitis media.
o Severe retraction of Pars tensa with contact into
promontory, but fixed.

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Riyadh et al. Notes
245

1159
Riyadh et al. Notes
246

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Riyadh et al. Notes
247
- Charachon Classification for TM Retractions:
ƒ Stage I:
o Mobile retraction pocket.
ƒ Stage II:
o Fixed and controllable retraction pocket.
ƒ Stage III:
o Fixed and uncontrollable retraction pocket.

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Riyadh et al. Notes
248
- Clinical picture:
ƒ May be asymptomatic.
ƒ Otalgia due to changes in middle ear pressure or
infection.
ƒ Conductive hearing loss due to middle ear effusion,
splinting of the tympanic membrane or erosion of the
ossicular chain.
ƒ Recurrent ear discharge due to cholestatoma formation.
- Diagnosis:
ƒ History and physical examination:
o Otological and nasal symptoms including allergy
should be reviewed.
o Thorough examination of Ear, nose and
nasopharynx should be done.
ƒ Examination under microscope:
o Ear should be thoroughly cleaned of cerumen and
debris retraction pocket is often hidden behind
them.
ƒ Pneumatic otoscopy:
o Essential in establishing whether pocket is
reversible (movable or fixated).
o Patient may be also asked to perform Valsalva
maneuver to inflate middle ear while otoscopy.
ƒ Audiometry:
o When air bone gap is significant all cases should be
considered for treatment.
ƒ Tympanometry:
o Helpful in establishing whether retraction pocket is
accompanied by middle ear fluid.
ƒ CT Temporal bone:
o Indicated in deep retraction pocket where the
bottom cannot be seen.
o Evaluate presence of cholestatoma and any bony
erosions.

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Riyadh et al. Notes
249
- Treatment:
ƒ Regular reassessment visits with audiological examination
are important to assess disease progression and monitor
for complications, such as cholesteatoma formation.
ƒ Important issues before decision making:
1. Anatomic status of the retraction pocket:
o Pars tensa or pars flacida RP:
ƒ Pars flaccida retraction pockets
developed quicker followed by quick
bone absorption, and faster formation
of cholesteatoma due to lack of fibrous
layer of TM and management should
be more aggressive.
o Controllable or uncontrollable RP:
ƒ If possible to see under microscope
the extent of the pocket or not it is
called controllable or incontrollable RP
o Mobile of Fixed RP:
ƒ If RP adheres to the middle ear
structures but cannot be reversed is
called fixed.
ƒ The one which adheres to the ossicles
and promontory but can be reversed
is called mobile.
2. Functional status of the ear (hearing):
o If the hearing does not exceed 20dB Air
Bone Gap (ABG) these RP should not be
treated.
3. Presence of chronic middle ear effusion:
o If retraction pocket is accompanied by
chronic middle ear effusion it can be
regarded as a proof of an active process in
the middle ear.
o Long lasting fluid together with negative
tympanic cavity pressure causes secondary
changes of TM and should be treated without
any delay.
4. Behavior of retraction pocket over time:
o In some individuals, RP progressively
proceeds to form adhesions and finally
cholesteatoma.
o If there is rapid progression over time, RP
should to be treated in order to prevent
progression to more advanced stages.

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Riyadh et al. Notes
250
- Management protocol of RP (Charachon Classification):

- Stage I (Mobile RP):

ƒ Wait and see policy.
ƒ If after 3 months no progression is observed, the patient
is followed up every three months, for two years.
ƒ Indications of surgery:
1. Hearing loss > 20dB ABG.
2. Presence of chronic middle ear effusion.
3. Progression of RP overtime.
ƒ Types of Surgery:
o Tympanostomy tube placement
o Excision of RP:
o It is reasonable not to excise to large areas
of TM since large perforation may persist.
o Excision should better be done if retraction is
limited to one quadrant.
o Pars flacida RP are not excised since there
o is a risk of in growth of squamous epithelium
and cholesteatoma formation at that area.

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Riyadh et al. Notes
251
- Stage II (Fixed and Controllable RP):
ƒ Wait and see policy.
ƒ If after 3 months no progression is observed, the patient
is followed up every three months, for two years.
ƒ Indications of surgery:
1. Hearing loss > 20dB ABG.
2. Presence of chronic middle ear effusion.
3. Progression of RP overtime.
ƒ Types of Surgery:
o Tympanostomy tube placement.
o T-tube with cartilage graft:
o T-tube for ventilation and cartilage for TM
reinforcement.
o Trans-canal approach, elevation of
tympanomeatal flap and separation of
middle ear adhesions, T-tube with cartilage
TM support is inserted.
o Cartilage tympanoplasty:
o Atelectatic membrane should be elevated or
excised and cartilage tympanoplasty should
be performed.

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252
- Stage III (Fixed and Uncontrollable RP):
ƒ Surgery should be performed to prevent cholesteatoma
formation.
ƒ Temporal bone CT scan should be done to assess the
extent of RP before surgery.
ƒ Types of Surgery:
o Cartilage tympanoplasty:
o Most authors advocate Cartilage
tympanoplasty.
o Atelectatic membrane should be elevated or
excised and cartilage tympanoplasty should
be performed.
o Tympanomastoidectomy with posterior
tympanotomy:
o For more extent cases.
o With or without ossicular reconstruction.
o If RP is ruptured during surgery, second look
o surgery should be planned in the future to
exclude residual cholesteatoma.

o Tympanosclerosis:
- Deposition of hyaline and calcium within submucous layer of
tympanic membrane (Myringosclerosis) or middle ear cavity
(Intratympanic Tympanosclerosis).

- Myringosclerosis:
- Hyalinization and calcification of fibrous layer of tympanic
membrane only.
- Clinical picture:
ƒ Chalky white cresentic shaped plaque.
ƒ Mostly, it remains asymptomatic and does
not affect the hearing.
ƒ No myringosclerosis will develop in the area
of healed TM perforation because it lacks a
fibrous middle layer.
- Causes:
ƒ TM trauma
ƒ After grommet insertion
ƒ Chronic otitis media with effusion
- Treatment:
ƒ Observation

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253
- Intratympanic Tympanosclerosis:
- Hyalinization and calcification of submucous layer of
middle ear cavity.
- Clinical picture:
ƒ Chalky white bone-like mass located anywhere
in middle ear cavity but more commonly in:
o Epitympanum
o Promontory
o Ossicles
ƒ Associated with marked conductive or mixed hearing loss
and the degree of hearing loss depends on the extent of
tympanosclerotic involvement of the ossicular chain.
- Causes:
ƒ Chronic otitis media with effusion
ƒ Recurrent acute otitis media
ƒ Autoimmune process
- Tympoanosclerosis Vs Otosclerosis:
ƒ Pre-op:
o Tympoanosclerosis
o History of recurrent otitis media.
o Slowly progressive CHL.
o Appears earlier in life.
o Negative family history of otosclerosis.
o Myringosclerosis on examination.
o False cahart notch on PTA.
o Otosclerosis:
o No history of recurrent otitis media.
o Slowly progressive CHL.
o Appears in 2nd or 3rd decade of life.
o Positive family history of otosclerosis.
o Intact TM on examination.
o Cahart notch on PTA.
ƒ Intra-op:
o Tympanosclerosis covering footplate of stapes
could easily be mistaken for otosclerosis since both
fix footplate and look similar.
o Tympanosclerosis:
o Confined to mucosa covering the footplate
and other parts of the middle ear.
o Can be peeled off.
o Otosclerosis:
o Invades and replaces bone.
o Requires removal of at least a part of the
footplate to restore hearing.

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254
- Staging of Tympanosclerosis:
1. Myringosclerosis only.
2. Fixed incudomalleolar joint with mobile stapes.
3. Fixed stapes with mobile incudomalleolar joint.
4. Completely fixed ossicular chain.

- Treatment:
ƒ Management of tympanosclerosis is depending on the
staging and degree of involvement:
o Stage 1:
o Observation.
o Stage 2:
o Mobilize the incudomalleolar joint if possible.
o Remove the incus and do either incus
transposition or incus replacment prosthesis
between stapes and mallues.
o Stage 3:
o Mobilize the stapes.
o Stapedectomy.
o Stage 4:
o Conservative with hearing aids.

ƒ Important points:
o Results of surgical treatment of CHL in
tympanosclerosis is unpredictable and sometimes
unsatisfactory.
o Tympanosclerotic plaques are difficult to remove.
o Risk of recurrence and refixation of ossicles over
time.
o Risk of inner ear trauma mainly during mobilization
or stapedectomy

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255
o TM Perforation:
- Tympanic membrane may be perforated by:
ƒ Trauma:
x FB
x Unskilled instrumentation.
ƒ Sudden change in air pressure:
x Slap or a kiss on the ear.
x Sudden blast.
x Forceful Valsalva may rupture a thin atrophic
membrane.
ƒ Pressure by a fluid column:
x Diving, water sports.
ƒ Fracture of temporal bone.
ƒ AOM
ƒ CSOM

1169
Tympanic Membrane Perforation 256
• Pathophysiology:
acute/chronic otitis media (most common cause), persistent perforation after extrusion of a
PE tube, trauma (eg, cotton swab/foreign body, hard blow to the ear, barotrauma, diving,
water skiing, Explosive blasts can produce more than 200 dB sound pressure level (SPL).,
forceful irrigation, slag burn), iatrogenic, cholesteatoma (associated with marginal
perforations)

• spontaneous closure of a perforated TM results in a dimeric membrane (“monomeric” is a

misnomer as it contains two layers: outer epidermal and inner mucosal)

• Types
1. Central: perforation does not involve the annulus, typically infectious
2. Marginal: involves the annulus, less likely to resolve spontaneously, higher association
with cholesteatoma
3. Subtotal: involving nearly the entire TM
4. Total: involving entire TM

• SSx:
CHL, tinnitus, aural fullness, otorrhea

• Dx:
otoscopic exam, audiogram, tympanometry (type B, large volume >1.5 mL)

• Rx:
keep ear dry; tympanoplasty for persistent perforation, recurrent otitis media, CHL, or co-
existing cholesteatoma.

• Complications:
Rupture of the TM may be associated with following complications:
Facial paralysis - Subluxation of stapes - Vertigo and nystagmus - Sensorineural hearing loss
Riyadh et al. Notes
257
o Atrophic tympanic membrane:
- A normal tympanic membrane consists of
outer epithelial, middle fibrous and inner
mucosal layer.
- In serous otitis media, the middle fibrous layer
gets absorbed leaving a thin drumhead which
easily gets collapsed with eustachian tube
insufficiency.
- A perforation of tympanic membrane also
heals only by epithelial and mucosal layers
without the intervening fibrous layer.

o Bullous Myringitis:
- Characterized by formation of
serous/hemorrhagic bullae on epithelial surface
of tympanic membrane and deep meatus.
- Etiology:
ƒ Probably viral in origin.
ƒ Caused by same viruses or bacteria that
cause middle ear infections.
ƒ Despite common belief, Mycoplasma
pneumoniae is an extremely rare
causative agent.
- Clinical picture:
ƒ Sudden severe pain in the ear.
ƒ Blood-stained discharge when the bullae rupture.
ƒ Hearing loss.
- Treatment:
ƒ Analgesics is directed to give relief from pain.
ƒ Antibiotics are given for secondary infection of the ear
canal if the bulla has ruptured.
ƒ Severity of pain may warrant decompression of tense
bullae with a sterile straight needle.

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258
Acute Suppurative Otitis Media:
9 It is an acute (<3 weeks)
inflammation of middle ear
by pyogenic organisms.
9 middle ear implies middle
ear cleft, i.e.
x eustachian tube
x middle ear
x attic,
x aditus antrum
x mastoid air cells

9 The highest incidence of otitis media occurs between the ages of 6 and 12
months and decreases with age
9 Most children experience at least one episode of AOM during their childhood

™ Aetiology
9 follows viral infection of upper respiratory tract but soon the pyogenic
organisms invade the middle ear.
9 second most common disease in infants and children especially in children of
lower socio-economic group (upper respiratory infection is the most
common)

™ Routes of Infection
9 1. Via eustachian tube
o most common route.
o Infection travels via the lumen of the tube or along subepithelial peritubal
lymphatics.
o Eustachian tube in infants and young children is shorter, wider and
more horizontal and thus may account for higher incidence of infections
in this age group “ by the age of 7 years, when the tube has a more adult
configuration, the prevalence of otitis media is low “
o Breast or bottle feeding in a young infant in horizontal position may force
fluids through the tube into the middle ear and hence the need to keep
the infant propped up with head a little higher.
o Swimming and diving can also force water through the tube into the
middle ear.
9 2. Via external ear
o Traumatic perforations of tympanic membrane due to any cause open a
route to middle ear infection.
9 3. Blood-borne
o This is an uncommon route

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259
™ Risk Factors

9 Anything that interferes with normal functioning of eustachian tube results

in negative middle ear pressures leading to:-
o an influx of bacteria and viruses from the NP when the ET opens
o transudative fluid collection in the middle ear space predisposes to
middle ear infection.

9 host risk factors

1. Age (highest incidence of AOM is between 6 and 11 months of age)
2. Gender (Male)
3. Race (black)
4. Genetic predisposition
5. Ciliary dyskinesia (Kartagener syndrome)
6. Adenoids , tonsil , Chronic rhinitis and sinusitis (reservoir of infection &
mechanical ET obstruction)
7. ET dysfunction (short, horizontal, compliant)
8. Cleft palate “ After surgical repair of the palate, some pt the occurrence
of otitis media is reduced” , Craniofacial abnormality, Down’s , Apert;
mucopolysaccharidoses , Treacher Collins syndrome
9. Immune deficiency (especially IgA and IgG subclass 2 and 3 deficiencies)
10. allergy (disputed) “middle ear mucosa acts as a shock organ”
11. +ve family Hx
12. Gastroesophageal reflux

9 Environmental risk factors

1. URTIs ( most common)
2. Daycare attendance (2.6x)
3. Season (Fall/Winter)
4. Older siblings
5. Parental history of OM
6. Passive smoking
7. Low S/E status (overcrowding, poor sanitation)
8. Lack of breastfeeding
9. Night-time bottle (horizontal position)
10.Pacifier use “possibly due to the sucking action of the child propelling
nasopharyngeal: secretions into the middle ear or by the pacifier acting
as a fomite”
11.NGT , packing of nose or nasopharynx for epistaxis
12.Obesity.

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260
™ Bacteriology
9 Most common organisms in infants and young children are
x Streptococcus pneumoniae (30%) (Gram-positive, alpha-hemolytic)
x Haemophilus influenzae (20%) (Gram-negative aerobic,coccobacilli)
x Moraxella catarrhalis (12%) (Gram-negative, aerobic)
9 Other organisms include
x Streptococcus pyogenes (called Group A (beta-hemolytic) Streptococcus )
x Staphylococcus aureus (anaerobic Gram-positive coccal )
x Pseudomonas aeruginosa. ( Gram-negative aerobic, coccobacillus )
9 In about 18-20%, no growth is seen.
9 Many of the strains of H. influenzae (34%) and Moraxella catarrhalis(100%)
are β-lactamase producing.
9 if immunocompromised, look for oddities (Mycoplasma, Chlamydia)
x viral pathogens 4 – RRIP!(RSV “mos common” , rhino, influ, parainflu) are
often present alone (sterile otitis media) or potentiate bacterial pathogens

9 Pathogen causing bilateral, dull TM, non-mobile, T > 37°C

o Heamophilus influenzae
9 Pathogen causing unilateral, bulging TM, T > (38.1)°
o Streptococcus pneumoniae
9 Pathogen causing bullous myringitis
o Streptococcus pneumoniae
o Others include Mycoplasma, H. flu, Beta-hemolytic strep, M.catarrhalis,
Parainfluenza & influenza viru
9 Pathogen causing spontaneous
o Streptococcus pyogenes

In neonates and young infants, S. pneumoniae and H. influ are still the
most common

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261
™ Pathology and Clinical Features
9 The disease runs through the following stages:
9 1. Stage of tubal occlusion
9 Oedema and hyperaemia of nasopharyngeal end of eustachian tube
blocks the tube, leading to absorption of air and negative intratympanic
pressure.
9 retraction of tympanic membrane with some degree of effusion in the
middle ear but fluid may not be clinically appreciable.
9 Symptoms.
x Deafness and earache “not marked”
x generally no fever.
9 Signs.
x Tympanic membrane is retracted with handle of malleus assuming a
more horizontal position, prominence of lateral process of malleus
x loss of light reflex
x Tuning fork tests show conductive deafness.

9 2. Stage of pre-suppuration
9 If tubal occlusion is prolonged
9 pyogenic organisms invade tympanic cavity causing hyperaemia of its
lining.
9 Inflammatory exudate appears in the middle ear.
9 Tympanic membrane becomes congested.
9 Symptoms.
x Earache marked disturb sleep and throbbing nature.
x Deafness and tinnitus are also present, only by adults.
x high degree of fever and is restless usually, runs in child.
9 Signs.
x begin with
o congestion of pars tensa.
o Leash of blood vessels radiate from handle of malleus to the
periphery of tympanic membrane imparting it a cart-wheel
appearance.
x Later,
o whole of tympanic membrane including pars flaccida becomes
uniformly red.
o Tuning fork tests will again show conductive type of hearing loss.

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9 3. Stage of suppuration
9 This is marked by formation of pus in the middle ear and to some extent
in mastoid air cells.
9 Tympanic membrane starts bulging to the point of rupture.
9 Symptoms.
x Earache becomes excruciating.
x Deafness increases
x child may run fever
x may be accompanied by vomiting and even convulsions.
9 Signs.
x Tympanic membrane appears red and bulging with loss of landmarks.
x Handle of malleus may be engulfed by the swollen and protruding
tympanic membrane and may not be discernible.
x yellow spot (blister) may be seen on the tympanic membrane where
rupture is imminent.
x Tenderness may be elicited over the mastoid antrum.
9 X-rays of mastoid will show clouding of air cells because of exudate.

9 4. Stage of resolution
9 The tympanic membrane ruptures with release of pus and subsidence of
symptoms.
9 Inflammatory process begins to resolve.
9 If proper treatment is started early or if the infection was mild, resolution
may start even without rupture of tympanic membrane.
9 Symptoms.
x earache is relieved, fever comes down and pt feels better.
9 Signs.
x External auditory canal may contain blood-tinged discharge which later
becomes mucopurulent.
x Mucoid discharge from an ear must mean that there is a perforation of
the tympanic membrane.There are no mucous glands in the external
canal.
x Usually small perforation is seen in antero-inferior quadrant of pars
tensa.
x Hyperaemia of tympanic membrane begins to subside with return to
normal colour and landmarks.

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Riyadh et al. Notes
263

9 5. Stage of complication
9 If virulence of organism is high or resistance of patient poor, resolution
may not take place and disease spreads beyond the confines of middle ear.
9 It may lead to:-
Intratemporal complications of Intracranial complications of
AOM AOM

o Chronic suppurative OM o Meningitis (#1, HiB >

o Adhesive otitis Pneumococcus, Mondini)
o Tympanic membrane perforation o Epidural/subdural/cerebral
o Cholesteatoma abscesses
o Tympanosclerosis o Focal encephalitis
o Fixation and Discontinuity of o Lateral/sigmoid sinus thrombosis
ossicular chain (Tobey-Ayer/Quesckenstedt’s
o Mastoiditis with or without Test; Griesinger’s sign))
Abscess (Postauricular, Bezold’s, o Otitic hydrocephalus
Zygomatic, Parapharyngeal, o Blindness with optic neuropathy
Retropharyngeal)
o Petrositis
o Labyrinthitis – Serous or
Suppurative
o Facial palsy
o Labyrinthine fistula (Pasha)
o CHL or SNHL

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Riyadh et al. Notes
264

™ Diagnosis :-
9 clinical and physical exam “ears, a proper head and neck examination is
invaluable, because it may identify condition that may predispose “
9 audiogram (CHL <30 dB) and tympanometry

™ PREVENTION OF DISEASE
1. MANAGEMENT OF RIEK FACTORS
9 Promotion of breastfeeding in the first 6 months of life
9 Avoidance of supine bottle feeding and pacifier use
9 Elimination of passive tobacco smoke .
9 Alteration of child care arrangements so that the child is exposed to fewer
children

2. VACCINES
9 Bacterial Vaccines
9 Streptococcus pneumoniae Vaccine
9 Haemophilus influenzae Vaccine
9 Moraxella catarrhalis Vaccine
9 Viral Vaccines
9 Influenza Vaccine
9 Respiratory Syncytial Virus Vaccine

1177
Riyadh et al. Notes
265

™ Treatment
1. Antibacterial therapy
9 It is indicated in all cases with fever and severe earache.
9 As the most common organisms are Strept. pneumoniae and H. influenzae,
the drugs which are effective in acute otitis media are amoxicillin.
9 amoxicillin-clavulanate (augmentin) Recommended
o for children who have been treated with amoxicillin in the previous 30
days
o for those with concurrent purulent conjunctivitis
o for those with a history of recurrent AOM unresponsive to amoxicillin. “β-
lactamase-producing H. influenzae or Moraxella catarrhalis”
9 if allergic to these penicillins can be given Cephalosporins such as cefdinir,
cefuroxime, cefpodoxime, and ceftriaxone
9 Antibacterial therapy must be continued for of 7-10 days, till tympanic
membrane regains normal appearance and hearing returns to normal.
9 typically resolves infection within 72 hours; if no resolution may consider
broader spectrum coverage ( augmentin , ceftrixon+ clindamycin)
9 Early discontinuance of therapy with relief of earache and fever, or therapy
given in inadequate doses may lead to secretory otitis media and residual
hearing loss.
9 Tympanocentesis should always be considered if the child does not respond
to the antibiotic treatment, in order to identify the bacteria in the MEE and to
select an appropriate antibiotic.

1178
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Riyadh et al. Notes
267

2. Decongestant nasal drops

9 should be used to relieve eustachian tube oedema and promote ventilation of
middle ear.
o Ephedrine nose drops (1% in adults and 0.5% in children)
o oxymetazoline (Nasivion)
o xylometazoline (Otrivin)
9 nasal drops is traditional but its value is uncertain in the presence of acute
inflammation of the middle ear.

3. Oral nasal decongestants

9 Pseudoephedrine OR combination of decongestant and antihistaminic
9 may achieve the same result without resort to nasal drops which are difficult
to administer in children.
4. Analgesics and antipyretics
9 Paracetamol helps to relieve pain and bring down temperature.
9 Avoid the use of aspirin in children because of the risk of Reye’s syndrome.
5. Ear toilet

9 If the ear is already discharging when the patient is first seen, a swab
shouldbe sent for culture of the organism
6. Dry local heat
9 It helps to relieve pain.
7. Myringotomy
9 It is incising the drum to evacuate pus and is indicated when
a. drum is bulging and there is severe acute pain or toxic patients
b. there is an incomplete resolution despite antibiotics when drum
remains full with persistent conductive deafness
c. there is persistent effusion beyond 12 weeks (3 month).
d. Complications of acute otitis media, e.g. facial paralysis, labyrinthitis
or meningitis with bulging tympanic membrane

9 helpful for relief of pain and allows samples to be obtained for culture to
identify the pathogen and to guide in the selection of antibiotics, but provides
no advantage in duration of effusion or recurrence of episodes of AOM

All cases of acute suppurative otitis media should be carefully followed till
drum membrane returns to its normal appearance and conductive deafness
disappears If resolution does not occur, suspect:
1 the nose, sinuses or nasopharynx? Infection may be present;
2 the choice or dose of antibiotic;
3 low-grade infection in the mastoid cells

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Riyadh et al. Notes
270
™ Recurrent Acute Otitis Media
9 4 or more AOM in 1 yr, or 3 or more in 6/12
9 Infants and children between the age of 6 months and 6 years may get
recurrent episodes of acute otitis media.
9 Usually, they occur after acute upper respiratory infection, the child being
free of symptoms between the episodes
9 Recurrent middle infections may sometimes be superimposed upon an
existing middle ear effusion.
9 Sometimes, the underlying cause is
o recurrent sinusitis
o velopharyngeal insufficiency
o hypertrophy of adenoids
o infected tonsils allergy
o immune deficiency as " IgA deficiency or hypogammaglobulinaemia".
o Feeding the babies in supine position without propping up the head may
cause the milk to enter the middle ear directly that can lead to middle ear
infection.

9 Management of such children involves:

x 1. Finding the cause and eliminating it, if possible.

x 2 Myringotomy and insertion of tympanostomy tube “guidelines (2013)
recommend against insertion of tympanostomy tubes in children with
recurrent AOM who do not have MEE “
x 3. Antimicrobial prophylaxis.
o disadvantage of creating antimicrobial resistance or hypersensitivity
reaction
o not preferred by many in favour of early insertion of tympanostomy
tubes.

x Adenoidectomy may provide modest improvement in children with

recurrent AOM but is not recommended as a firstline procedure unless
indicated for airway obstruction.

x Tonsillectomy, in conjunction with adenoidectomy, provides no significant

advantage over adenoidectomy alone, and the risk outweigh the benefits.

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™ ACUTE NECROTISING OTITIS MEDIA

9 It is a variety of acute suppurative otitis media,
9 often seen in children suffering from measles, scarlet fever or influenza.
9 Causative organism is β-haemolytic streptococcus.
9 There is rapid destruction of whole of tympanic membrane with its annulus,
mucosa of promontory, ossicular chain and even mastoid air cells.
9 There is profuse otorrhoea.
9 healing is followed by fibrosis or ingrowth of squamous epithelium from the
meatus (secondary acquired cholesteatoma).
9 Treatment
x Antibacterial therapy. It is continued for at least 7-10 days, even if
response is seen early.
x Cortical mastoidectomy may be indicated if medical treatment fails to
control or the condition gets complicated by acute mastoiditis.

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CLINICAL PRACTICE GUIDELINE The Diagnosis and Management of Acute

Otitis Media From THE AMERICAN ACADEMY OF PEDIATRICS 2013

o Evidence-based clinical practice guideline is a revision of the 2004 acute otitis

media (AOM) guideline from the American Academy of Pediatrics (AAP) and
American Academy of Family Physicians.

o It provides recommendations to primary care clinicians for the management

of children from 6 months through 12 years of age with uncomplicated AOM.

Statement 1A:
Clinicians should diagnose acute otitis media (AOM) in children who present with
moderate to severe bulging of the tympanic membrane (TM) or new onset of
otorrhea not due to acute otitis externa.
Evidence Quality: Grade B. Strength: Recommendation.

Statement 1B:
Clinicians may diagnose AOM in children who present with mild bulging of the TM
and recent (less than 48 hours) onset of ear pain (holding, tugging,
rubbing of the ear in a nonverbal child) or intense erythema of the TM.
Evidence Quality: Grade C. Strength: Recommendation.

Statement 1C:
Clinicians should not diagnose AOM in children who do not have middle ear
effusion (MEE) (based on pneumatic otoscopy and/or tympanometry).
Evidence Quality: Grade B. Strength: Recommendation
.
Statement 2:
The management of AOM should include an assessment of pain. If pain is
present, the clinician should recommend treatment to reduce pain.
Evidence Quality: Grade B. Strength: Strong Recommendation.

Statement 3A:
Severe AOM: The clinician should prescribe antibiotic therapy for AOM (bilateral or
unilateral) in children 6 months and older with severe signs or symptoms (ie,
moderate or severe otalgia or otalgia for at least 48 hours or temperature 39°C
[102.2°F] or higher).
Evidence Quality: Grade B. Strength: Strong Recommendation.

Statement 3B:
Non severe bilateral AOM in young children: The clinician should prescribe
antibiotic therapy for bilateral AOM in children 6 months through 23 months of age
without severe signs or symptoms (ie, mild otalgia for less than 48 hours and
temperature less than 39°C [102.2°F]).
Evidence Quality: Grade B. Strength: Recommendation.

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Statement 3C:
Non severe unilateral AOM in young children: The clinician should either
prescribe antibiotic therapy or offer observation with close follow-up based on joint
decision making with the parent(s)/caregiver for unilateral AOM in children 6
months to 23 months of age without severe signs or symptoms (ie, mild otalgia for
less than 48 hours and temperature less than 39°C [102.2°F]).
When observation is used, a mechanism must be in place to ensure follow-up and
begin antibiotic therapy if the child worsens or fails to improve within 48 to 72
hours of onset of symptoms.
Evidence Quality: Grade B. Strength: Recommendation.

Statement 3D:
Non severe AOM in older children: The clinician should either prescribe antibiotic
therapy or offer observation with close follow-up based on joint decision-making
with the parent(s)/ caregiver for AOM (bilateral or unilateral) in children 24 months
or
older without severe signs or symptoms (ie, mild otalgia for less than 48 hours and
temperature less than 39°C [102.2°F]).
When observation is used, a mechanism must be in place to ensure follow-up and
begin antibiotic therapy if the child worsens or fails to improve within 48 to 72
hours of onset of symptoms. Evidence Quality: Grade B. Strength:
Recommendation.

Statement 4A:
Clinicians should prescribe amoxicillin for AOM when a decision to treat with
antibiotics has been made and the child has not received amoxicillin in the past 30
days or the child does not have concurrent purulent conjunctivitis (otitis-
conjunctivitis syndrome) or the child is not allergic
to penicillin.
Evidence Quality: Grade B. Strength: Recommendation.

Statement 4B:
Clinicians should prescribe an antibiotic with additional β-lactamase coverage
for AOM when a decision to treat with antibiotics has been made, and the child has
received amoxicillin in the last 30 days or has concurrent purulent conjunctivitis, or
has a history of recurrent AOM unresponsive to amoxicillin.
Evidence Quality: Grade C. Strength: Recommendation.

Statement 4C:
Clinicians should reassess the patient if the caregiver reports that the child’s
symptoms have worsened or failed to respond to the initial antibiotic treatment
within 48 to 72 hours
and determine whether a change in therapy is needed.
Evidence Quality: Grade B. Strength: Recommendation.

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Statement 5A:
Clinicians should not prescribe prophylactic antibiotics to reduce the frequency of
episodes of AOM in children with recurrent AOM.
Evidence Quality: Grade B. Strength: Recommendation.

Statement 5B:
Clinicians may offer tympanostomy tubes for recurrent AOM (3 episodes in 6
months or 4 episodes in 1 year with 1 episode in the preceding 6 months).
Evidence Quality: Grade B. Strength: Option.

Statement 6A:
Clinicians should recommend pneumococcal conjugate vaccine to all children
Evidence Quality: Grade B. Strength: Strong Recommendation.

Statement 6B:
Clinicians should recommend annual influenza vaccine to all children
Evidence Quality: Grade B. Strength: Recommendation.

Statement 6C:
Clinicians should encourage exclusive breastfeeding for at least 6 months.
Evidence Quality: Grade B. Strength: Recommendation.

Statement 6D:
Clinicians should encourage avoidance of tobacco smoke exposure.
Evidence Quality: Grade C. Strength: Recommendation.

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Otitis Media With Effusion:

9 Also known
x Serous Otitis Media
x Secretory Otitis Media
x Mucoid Otitis Media
x "Glue Ear"
9 persistence of fluid in the middle ear space without evidence of infection"
non-purulent " effusion in the middle ear cleft.
9 Often the effusion is thick and viscid but sometimes it may be thin and
serous.
9 The fluid is nearly sterile.
9 Time that fluid has to be present for the condition to be chronic is
usually taken as 12 weeks
9 patients with a history of chronic OME have more sclerotic mastoids with
decreased pneumatization compared with healthy subjects.
9 Two theories
o hereditary theory states that children with hypoaeration of the mastoid
are prone to OME,
o environmental theory states that chronic OME results in
hypopneumatization of the mastoid.

™ Epidemiology
y First Episode
{ 50% of all children- before the first birthday
{ 80% of all children - before the third birthday
y Prevalence bimodal at 2 & 5 yrs when child first attends playgroup school
& when goes to primary school
y Above 15 yrs Æ prevalence 0.6%
y More during winters
y More than a third of consultations to pediatricians each year
y M>F

™ Pathogenesis
x Two main mechanisms are thought to be responsible:
9 1. Malfunctioning of eustachian tube
Eustachian tube fails to aerate the middle ear and is also unable to drain the
fluid.
9 2. Increased secretory activity of middle ear mucosa
Biopsies of middle ear mucosa in these cases have confirmed increase in
number of mucus or serous-secreting cells.

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™ Aetiology

9 1. Malfunctioning of eustachian tube, the causes are:

x (i) Adenoid hyperplasia.

x (ii) Chronic rhinitis and sinusitis.
x (iii) Chronic tonsillitis. "Enlarged tonsils mechanically obstruct the
movements of soft palate and interfere with the physiological opening of
eustachian tube".
x (iv) Benign and malignant tumours of nasopharynx. This cause should
always be excluded in unilateral serous otitis media in an adult.
x (v) Palatal defects, e.g. cleft palate, palatal paralysis.( Although some
studies have shown that the incidence of middle-ear disease decreases
after surgical repair of the cleft palate, many children with a cleft palate
continue to have middle-ear problems)
x (vi) Oedema during radiation therapy
x (vii) Syndromes: Down’s; Apert; mucopolysaccharidoses

9 2. Allergy AND IMMUNOLOGY

x Seasonal or perennial allergy to inhalants
x foodstuff :- milk
x not only obstructs eustachian tube by oedema but may also lead to
increased secretory activity as middle ear mucosa acts as a shock organ
in such cases.
x History of immunological disorders (especially IgA and IgG subclass 2 and
3 deficiencies) Recurrence of bilateral OME

9 3. Unresolved otitis media

x ≈10% of acute otitis media cases have persistent fluid 3 months after
resolution of the infection
x Inadequate antibiotic therapy in acute suppurative otitis media may
inactivate infection but fail to resolve it completely "Low grade infection ".
x Biofilms also have been identified in the nasopharynx of children with
otitis media, and it was suggested that the biofilm may act as a reservoir
for bacterial pathogens resistant to antibiotics “Mechanical debridement of
nasopharyngeal biofilms may explain the observed clinical benefit
associated with adenoidectomy in subsets of pediatric patients”
x Low grade infection , biofilm, acts as stimulus for mucosa to secrete more
fluid & number of goblet cells and mucous glands also increase.

9 4. bacterial , Viral infections

x Various “syncytial virus (RSV), influenzavirus, adenovirus, parainfluenza
virus, and rhinoviruses” of upper respiratory tract may invade middle ear
mucosa and stimulate it to increased secretory activity.
x H. influenzae was the single most common bacterial pathogen, with S.

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pneumoniae, M. catarrhalis,

9 5.gastroesophageal reflux
x may be a causative factor in otitis media,
x potential role for antireflux therapy in the treatment of otitis media in
some children.
x Adequately controlled trials have not yet been done.

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™ Risk Factors

9 host risk factors

1. Age ( < 2 year)
2. Gender (Male)
3. Race (Caucasian)
4. Genetic predisposition
5. Ciliary dyskinesia (Kartagener syndrome)
6. Cystic fibrosis
7. Adenoids , tonsil , Chronic rhinitis and sinusitis (reservoir of infection
& mechanical ET obstruction)
8. ET dysfunction (short, horizontal, compliant)
9. Cleft palate “ After surgical repair of the palate, some pt the
occurrence of otitis media is reduced” , Craniofacial abnormality,
Down’s , Apert; mucopolysaccharidoses , Treacher Collins syndrome
10. Immune deficiency (especially IgA and IgG subclass 2 and 3
deficiencies)
11. allergy (disputed) “middle ear mucosa acts as a shock organ”
12. +ve family Hx
13. Gastroesophageal reflux
14. Poor mastoid pneumatization

9 Environmental risk factors

1. URTIs , post AOM
2. Daycare attendance with > 4 children
3. Season (Fall/Winter)
4. Passive smoking
5. Low S/E status (overcrowding, poor sanitation)
6. Lack of breastfeeding
7. Night-time bottle (horizontal position)
8. Pacifier use “possibly due to the sucking action of the child propelling
nasopharyngeal: secretions into the middle ear or by the pacifier
acting as a fomite”

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™ Clinical Features

9 Symptoms
x The disease affects children of 5-8 years of age. The symptoms include:
i. Hearing loss.
o sometimes the only symptom.
o insidious in onset and rarely exceeds 40 dB.
o Deafness may pass unnoticed by the parents and may be accidentally
discovered during audiometric screening tests.
i. Delayed and defective speech Poor Academics in children.
ii. Mild earaches & tinnitus.
o There may be history of upper respiratory tract infections with mild
earaches ( fullness) .

9 Otoscopic findings ( sensitivity 85 – 93%)

x Tympanic membrane is often dull and opaque with loss of light reflex.
x It may appear yellow, grey or bluish in colour.
x Thin leash of blood vessels may be seen along the handle of malleus or at
the periphery of tympanic membrane and differs from marked congestion of
acute suppurative otitis media.
x Tympanic membrane may show varying degree of retraction.
x may appear full or slightly bulging in its posterior part due to effusion.
x Fluid level and air bubbles may be seen when fluid is thin and tympanic
membrane transparent
x Mobility of the tympanic membrane is restricted.

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9 Hearing Tests
1. Tuning fork tests show conductive hearing loss.
2. Audiometry. (sensitivity 92 %)
9 conductive hearing loss of 20-30 dB (rarely exceeds 40 dB).
9 Sometimes, there is associated sensorineural hearing loss due to fluid
pressing on the round window membrane.
9 This disappears with evacuation of fluid.
3. Impedance audiometry (Tympanometry) (sensitivity 96 %)
9 It is an objective test useful in infants and children.
9 Presence of fluid is indicated by reduced compliance and flat curve
with a shift to negative side.

Most common cause for bilateral conductive deafness in a child is Otits media with effusion

4. Effusion is the main cause of failed newborn OAE

5. ABR is excellent methods for testing children who do not cooperate with
behavioral hearing evaluation because of very young age or
developmental delay

9 Radiology
9 X ray Skull Lateral View
o Adenoid Hyperplasia
9 Xray Mastoid Schuller’s View
o Clouding
9 MRI
o Absence of fluid does not imply an absence of OME, as one-third of
patients in MRI study had fluid in mastoid, but not in the
mesotympanum (Kew et al)

9 Nasopharynx evaluation

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™ Treatment
x The aim of treatment is removal of fluid and prevention of its recurrence.
o MEDICAL
o SURICAL

A. Medical
9 mainly observation until fluid resolved, or until hearing compromised For
children not at risk for speech and language or learning disabilities
9 For children not at risk & asymptomatic , examination at 3- to 6-month
intervals is recommended until
x fluid has resolved
x hearing loss or language or learning delays are identified;
x structural abnormalities of the eardrum are suspected

9 Who at risk?

1. Decongestants & Antihistamin , intranasal steroid

o popular treatment for OME, but In studies of OME at the Children’s Hospital
of Pittsburgh, no efficacy was found for an oral decongestant-antihistamine
combination given either alone or with an antimicrobial agent
o randomized doubleblind, placebo-controlled trial of intranasal mometasone
furoate spray in 217 children 4 to 11 years of age with bilateral OME found
no efficacy for clearance of effusion

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2. Antibiotics
o antibiotics are not recommended for routine treatment of OME, due to
x lack of long-term efficacy“ most pt had recurrence “
x high spontaneous cure rate
x overuse of antibiotics

x although effusions were thought to be sterile, studies showed that

specimens from asymptomatic children with MEE contained bacteria

x Mandel and colleagues reported the results of their doubleblind,

randomized trial in which 518 children with OME of varying durations were
divided into three treatment groups
o amoxicillin (40 mg/kg/day) for 14 days plus a
decongestantantihistamine combination for 28 days
o amoxicillin for 14 days plus placebo for decongestant-antihistamine
for 28 days,
o placebo for both amoxicillin and decongestant/ antihistamine.

x 4 weeks, the rate of resolution of MEE was twice as high in those treated
with amoxicillin with or without a decongestant-antihistamine
agent31.6%,, as those who received placebo 14.1%
x decongestant-antihistamine made no difference
x Recurrence of effusion occurred in most subjects within 3 months after
completion of treatment
x Other study show all antibiotics had the same efficacy , none has been
clearly shown to have any long-term advantage over the others

x Antimicrobials may be considered in some cases of parental refuse to

surgery
o 10-14 day course
o Unlikely to provide long term benefit
o Multiple courses not recommended ( only one course )

3. 4. Middle ear aeration (Autoinflation.)

o Patient should repeatedly perform Valsalva manoeuvre.
o This helps to ventilate middle ear and promote drainage of fluid.
o Children can be given chewing gum to encourage repeated swallowing which
opens the tube.
o Sometimes, politzerisation or eustachian tube catheterisation has to be done
??
o Autoinflation by devices is not recommended for routine use at this time

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B. Surgical
o When fluid persists > 3/12 or if HL,,, language delay suspected
o When fluid is thick and medical treatment alone does not help, fluid must be
surgically removed.

1. Myringotomy and aspiration of fluid (Tympanocentesis)

9 Myringotomy alone not recommended for chronic OME
9 An incision is made in tympanic membrane and fluid aspirated with
suction.
9 Thick mucus may require installation of
saline or a mucolytic agent like
chymotrypsin solution to liquefy mucus
before it can be aspirated.
9 Sometimes, two incisions are made in the
tympanic membrane, one in the antero-
inferior and the other in antero-superior
quadrant, to aspirate thick "beer-can" principle
9 The mean time to closure of the perforation is only 2 to 3 weeks

9 Indication for Myringotomy

1. Acute suppurative otiti media in a seriously-ill , sever pain ,
toxic, newborn or immune deficient patient
2. Complications of acute otitis media, e.g. facial paralysis,
labyrinthitis or meningitis with bulging tympanic membrane.
3. Unsatisfactory response to antibiotics drum remains full with
persistent conductive deafness
4. Suspected unusual pathogen (newborns, immunodeficiency) for
aspiration and culture

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2. Ventelation tube insertion

y (improves hearing by 12 dB)
y If myringotomy and aspiration
combined with medical measures
has not helped and fluid recurs
(malfunctioning eustachian tube), a
grommet is inserted to provide
continued aeration of middle ear.
y It is left in place for weeks or
months or till it is spontaneously
extruded.

y Grommet Stay up to 6 mths to 1 year

y T tubes stay upto 1-2 yrs
y The time to extrusion is a function of :-
o Size
o shape of the medial flange
o absence of a lateral flange
o material of the tube

y Materials for tubes

o Silicone
o Teflon
o Stainless steel
o Titanium
o Gold
x T-tubes recommended for :-
o Adult & older children with persistent problems due to poor
eustachian tube function.
o for atrophic TM after going through multiple sets of
tympanostomy tubes, because a regular grommet tube may be
very quickly extruded.

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y Indication.

o Recurrent AOM (>3 in 6 month , >4 in 1 year, with failed medical

management)
(OPTION)
o OME
ƒ bilateral >3 month or unilateral >6 month
ƒ earlier when >40 db CHL
ƒ speech/language delay
ƒ severe retraction pocket,
ƒ disequilibrium/vertigo, or tinnitus present
o Eustachian tube dysfunction with autophony, disequilibrium or
ƒ vertigo, tinnitus, or Atelectatic TM/severe retraction pocket,
unrelieved by medical management
o Patulous eustachian tube
o Barotitis media(Aero-otitis media ) /Hyperbaric oxygen therapy
o Suspected unusual pathogen
o Suppurative complication, present or suspected
o Unsatisfactory response to antibiotics

x Steps of Operation
1. Ear canal is cleaned of wax and debris.
2. Operation is ideally performed under operating microscope using a
sharp myringotome and a good suction apparatus.
3. In acute suppurative otitis media, a circumferential incision is made
in the posteroinferior quadrant of tympanic membrane, midway
between handle of malleus and tympanic annulus, avoiding injury to
incudostapedial joint
4. In serous otitis media, a small radial incision is given in the
posteroinferior , anteroinferior or anteriosuperior “controversy
regarding the best place” quadrant and all the effusion sucked out “
anterosuperior quadrant is associated with a longer clinical tube life;
however, a persistent perforation I that area is somewhat more
difficult to repair “

A. Pitfalls of Myringotomy
1. When tympanic membrane is thick ( incision may remain only in the
superficial layers of drumhead without cutting through its entire
thickness)
2. Incision in the posterior meatal wall. (This may happen when
distinction between drum-head and posterior meatal wall is lost, when
both are inflamed.)

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9 Complications
y Intra op
o Displacement into middle ear
o Damage to incudostapedial joint or stapes
o Injury to jugular bulb with profuse bleeding, if jugular bulb is high and
floor of the middle ear dehiscent.
o Injury to external ear
y Early post op
o Blockage of tube by blood
o Granulation around tube “act as a foreign body”
o Ear infection
o Otorrhoea ( 3.5% rate of persistent drainage )
y If untreated, acute otorrhea can develop into CSOM
y ototopical agents such as ofloxacin and ciprofloxacin-
dexamethasone “ ciprodex” are effective
y child who has severe systemic symptoms, a systemic antibiotic
y If the drainage does not resolve in 7 to 10 days, suctioning and
sent to culture
y If treatment fail to produce improvement and the organisms
are not sensitive to oral antibiotics, then:-
1. intravenous antibiotics
2. removal of the tube(s)
3. rarely a simple mastoidectomy should be considered.
y In older children with recurrent episodes of otorrhea, removal of
the tubes is the treatment of choice
o Early extrusion “3.9%”
y Late post op
o Permanent perforation “3%”
o Tympanosclerosis “40%”
o TM atrophy & retraction “67%”
o Cholesteatoma “0.7%, for short-term tubes, 1.4% for long-term tubes
“

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9 Post-operative Care
o antimicrobial drops educe early postoperative otorrhea and tube
blockage
o Drum incisions usually heal rapidly. No water should be permitted to
enter the ear canal for at least 2 week for margnotomy
o if a grommet has been inserted, entry of water is prevented so long
as grommet is in position.
ƒ Several studies have been published, including two meta-
analyses demonstrating no increase in episodes of otorrhea in
patients with tympanostomy tubes not using water precaution
ƒ water precautions may be prudent for some children such as:-
9 those with recurrent episodes of otorrhea, particularly
with Pseudomonas or S. aureus,
9 and those with risk factors for infections and
complications.
9 heavily contaminated water (lakes) or nonchlorinated
swimming pools, for deep diving, dunking the head in
the bathtub with soapy water
9 children who experience ear discomfort during
swimming.
o follow-up visit a few weeks after the surgery for
o an otoscopic examination to assess the status of the
tympanostomy tube
o repeat hearing evaluation postoperatively

o F/U every 6 months to assess the status of the tubes and the TM.

9 Contraindications :- intratympanic glomus tumour. Myringotomy in

these cases can cause profuse bleeding.

3. Tympanotomy or cortical mastoidectomy

9 It is sometimes required for removal of loculated thick fluid or other
associated pathology such as cholesterol granuloma.
4. Surgical treatment of causative factor
9 Adenoidectomy, tonsillectomy may be required. This is usually done
at the time of myringotomy.
9 Adenoidectomy is not recommended for the initial surgical treatment
of otitis media unless nasal obstruction is present
9 recommended for children in whom a repeat surgical procedure is
needed

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™ Sequelae of Chronic Secretory Otitis Media

1. Atrophic tympanic membrane and atelectasis of the middle ear
o In prolonged effusions, fibrous layer of tympanic membrane dissolution
becomes thin and atrophic and retracts into the middle ear.
2. Ossicular necrosis
o Most commonly, long process of incus gets necrosed.
o Sometimes, stapes superstructure also gets necrosed.
o This increases the conductive hearing loss to more than 50 dB.
3. Tympanosclerosis
o Hyalinised collagen with chalky deposits may be seen in
ƒ tympanic membrane,
ƒ around the ossicles or their joints
o leading to their fixation.

4. Retraction pockets and cholesteatoma

o Thin atrophic part of pars tensa may get invaginated to form retraction
pockets or cholesteatoma.
o Similar pockets may be seen in the attic region.

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5. Cholesterol granuloma
o This is due to stasis of secretions in middle ear and mastoid.

Clinical Practice Guideline: Otitis Media with Effusion

9 Applicable to all children ages 2 months to 12 years with or without disability

(1)Pneumatic otoscopy
A. The clinician should document the presence of middle ear effusion with
pneumatic otoscopy when diagnosing otitis media with effusion (OME)
in a child. (Strong recommendation)

B. Pneumatic otoscopy The clinician should perform pneumatic otoscopy

to assess for OME in a child with otalgia, hearing loss, or both.
(Strong recommendation)

(2)Tympanometry
Clinicians should obtain tympanometry in children with suspected OME
for whom the diagnosis is uncertain after performing (or attempting)
pneumatic otoscopy.
(Strong recommendation)

(3)Failed newborn hearing screen

Clinicians should document in the medical record counseling of parents
of infants with OME who fail a newborn hearing screen regarding the
importance of follow-up to ensure that hearing is normal when OME
resolves and to exclude an underlying sensorineural hearing loss.
(Recommendation)

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(4)Children at-risk
A. Identifying at-risk children
Clinicians should determine if a child with OME is at increased risk for
speech, language, or learning problems from middle ear effusion
because of baseline sensory, physical, cognitive, or behavioral factors
(Recommendation)

B. Evaluating at-risk children

Clinicians should evaluate at-risk children for OME at the time
of diagnosis of an at-risk condition and at 12 to 18 mo of age (if
diagnosed as being at risk prior to this time)
(Recommendation)

(5)Screening healthy children

Clinicians should not routinely screen children for OME who are not at
risk and do not have symptoms that may be attributable to
OME, such as hearing difficulties, balance (vestibular) problems, poor
school performance, behavioral problems, or ear discomfort.
(Recommendation (against) )

(6)Patient education
Clinicians should educate families of children with OME regarding the
natural history of OME, need for follow-up, and the possible sequelae.
(Recommendation)

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(7)Watchful waiting

Clinicians should manage the child with OME who is not at risk with
watchful waiting for 3 mo from the date of effusion onset (if
known)
or 3 mo from the date of diagnosis (if onset is unknown)
(Strong recommendation)

y Likelihood of resolution determined by cause and duration of effusion

o 75-90% of episodes following AOM resolve by 3 months
o 55% of children newly diagnosed with OME with a flat
tympanogram will improvement (not resolution) change to a
non-type B tympanogram within 3 months of onset. One third
relapse in next 3 months
o 25% of newly detected OME of unknown duration in children
age 2-4 years resolves by 3 months based on tympanogram
o Resolution rates may be higher for infant and young children
o Documented bilateral OME of 3 months duration or longer
resolves in 30% of children 2 or older after 6-12 months
observation with only marginal benefits if observed longer

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(8)Medication

A. Steroids
Clinicians should recommend against using intranasal steroids or
systemic steroids for treating OME.
Strong recommendation (against)

B. Antibiotics
Clinicians should recommend against using systemic antibiotics for treating
OME.
(Strong recommendation (against) )

C. Antihistamines or decongestants
Clinicians should recommend against using antihistamines,
decongestants, or both for treating OME.
(Strong recommendation (against) )

9 No benefit for antihistamines and decongestants vs. placebo

9 Long-term benefits of antimicrobials unproven despite modest
short-term benefit for 2-8 weeks in randomized trials.
9 later metaanalysis show a short-term benefit for oral steroid plus
antimicrobial versus antimicrobial alone in 1 of 3 children treated
9 Benefits of abx become non-significant within 2 weeks of stopping
the medication
9 Adverse effects of antimicrobials are significant including rash,
vomiting, diarrhea, allergic reaction, alteration of nasopharyngeal
flora, bacterial resistance, and cost.
9 Side effects of oral steroids: weight gain, adrenal suppression,
avascular necrosis of femoral head

y Antimicrobials with or without steroids may be considered in some

cases of parental refuse to surgery
o 10-14 day course
o Unlikely to provide long term benefit
o Multiple courses not recommended

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294

(9) Hearing test

Clinicians should obtain an age-appropriate hearing test if OME persists
for > 3 mo or for OME of any duration in an at-risk child.
(Recommendation)

(10) Speech and language

Clinicians should counsel families of children with bilateral OME and
documented hearing loss about the potential impact on speech and
language development.
(Recommendation)

(11) Surveillance of chronic OME

Clinicians should reevaluate, at 3- to 6-mo intervals, children with
chronic OME until the effusion is no longer present, significant
hearing loss is identified, or structural abnormalities of the eardrum
or middle ear are suspected.
(Recommendation)
y “If OME is asymptomatic and is likely to resolve spontaneously, intervention is
unnecessary even if OME persists for more than 3 months”

(12) Surgery

A. children < 4 y old

Clinicians should recommend tympanostomy tubes when surgery is
performed for OME in a child less than 4 years old; adenoidectomy
should not be performed unless a distinct indication (eg, nasal
obstruction, chronic adenoiditis) exists other than OME.
(Recommendation)

B. children > = 4 y old

Clinicians should recommend tympanostomy tubes, adenoidectomy, or
both when surgery is performed for OME in a child 4 years old or
older.
(Recommendation)

(13) Outcome assessment

When managing a child with OME, clinicians should document in the
medical record resolution of OME, improved hearing, or improved
quality of life.
(Recommendation)

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™ AERO-OTITIS MEDIA (OTITIC BAROTRAUMA)

9 It is a non-suppurative condition resulting from failure of eustachian tube to
maintain middle ear pressure at ambient atmospheric level.
9 The usual cause is rapid descent during air flight, underwater diving or
compression in pressure chamber

™ Mechanism
9 Eustachian tube allows easy and passive egress of air from middle ear to
the pharynx if middle ear pressure is high.
9 In the reverse situation, where nasopharyngeal air pressure is high, air
cannot enter the middle ear unless tube is actively opened by the
contraction of muscles as in swallowing, yawning or Valsalva manoeuvre.
9 When atmospheric pressure is higher than that of middle ear by critical
level of 90 mm of Hg, eustachian tube gets "locked", i.e. soft tissues of
pharyngeal end of the tube are forced into its lumen.
9 In the presence of eustachian tube oedema, even smaller pressure
differentials cause "locking" of the tube.
9 Sudden negative pressure in the middle ear causes retraction of tympanic
membrane, hyperaemia and engorgement of vessels, transudation and
haemorrhages.
9 Sometimes, though rarely, there is rupture of labyrinthine membranes
with vertigo and sensorineural hearing loss.

™ Clinical Features
9 Severe earache, hearing loss and tinnitus are common complaints.
9 Vertigo is uncommon. Tympanic membrane appears retracted and
congested. It may get ruptured.
9 Middle ear may show air bubbles or haemorrhagic effusion.
9 Hearing loss is usually conductive but sensorineural type of loss may
also be seen.

™ Treatment
9 The aim is to restore middle ear aeration.
9 This is done by Valsalva manoeuvre
9 In mild cases, decongestant nasal drops or oral nasal decongestant
with antihistaminics are helpful.
9 In the presence of fluid or failure of the above methods,
myringotomy may be performed to "unlock" the tube and aspirate
the fluid.

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™ Prevention
x Aero-otitis can be prevented by the following measures:

1. Avoid air travel in the presence of upper respiratory infection or

allergy.
2. Swallow repeatedly during descent. Sucking sweets or chewing
gum is useful.
3. Do not permit sleep during descent as number of swallows
normally decrease during sleep.
4. Autoinflation of the tube by Valsalva should be performed
intermittently during descent.
5. Use vasoconstrictor nasal spray and a tablet of antihistaminic and
systemic decongestant, half an hour before descent in persons
with previous history of this episode.
6. In recurrent barotrauma, attention should be paid to nasal
polyps, septal deviation, nasal allergy and chronic sinus infections.

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OME 2016 Guidelines

o OME is diagnosed (or R/O) by either:

ƒ Pneumatic otoscope OR Tympanometry

o New child with OME and HL + NO RISK FACTORS:

1. Watchful waiting for 3M from Dx:
ƒ NO routine use of steroid, anti-histamine or decongestant
x Except if having concurrent AR.
ƒ No routine use of Abx.
ƒ May use Autoinflation technique.
2. Persistent OME after 3M F/U:
ƒ Request Hearing Test:
x IF Bilateral OME with HL > 20 dB:
o Surgery is RECOMMENDED:
ƒ IF Age < 4 Years:
x VT only
x Adenoidectomy (for patients with OME
and Adenoid Hypertrophy)
ƒ IF Age > 4 Years:
x VT + Adenoidectomy (Regardless
Adenoid size):
o Low rate of future revision
surgery compared to VT alone
(2% vs 20%).

x IF OME with symptoms other than HL (Vestibular

problems, poor school performance, behavioral
problems, ear discomfort):
o Surgery is OPTION.

x IF Unilateral OME or Bilateral OME with HL < 20 dB:

o Continuous observation with hearing testing every
3-6 M until either:
ƒ NO more OME.
ƒ Presence of an indication for surgery:
1. At-Risk patient.
2. Bilateral OME with > 20 dB.
3. Structural abnormality of TM or ME:
o Retraction pockets
o Ossicular erosion
o Areas of atelectasis or atrophy.
o Granulations or aural polyp.

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o New child with OME and HL + RISK FACTORS:

1. Request Hearing Test at initial visit.
2. Surgery is RECOMMENDED without watchful observation (Same
previous surgical approach).

o New child with RECURRENT AOM WITH OME at time of evaluation:

1. VT is RECOMMENDED without watchful observation.

o New child with RECURRENT AOM WITHOUT OME at time of

evaluation:
1. VT is NOT recommended.

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Chronic Suppurative Otitis Media (CSOM):

o Long-standing infection of a part or whole of the middle ear cleft

characterised by ear discharge and a permanent perforation.
o Persistent (>6 weeks) or recurrent drainage from infection of the
middle ear and/or mastoid in the presence of a TM perforation (or
ventilation tube).

™ Pathophysiology:
- Chronically inflamed or infected middle ear space or mastoid
secondary to:
o Poor aeration (chronic eustachian tube dysfunction),
o Chronic perforation,
o Presence of a Cholesteatoma.

- A perforation becomes permanent when its edges are covered by

Squamous epithelium and it does not heal spontaneously.
- A permanent perforation can be likened to an epithelium-lined fistulous
track.

™ Epidemiology:
- Incidence of CSOM is higher in Developing countries due to:
o Poor socio-economic standards
o Poor nutrition and lack of health education.
- Affects both sexes and all age groups.

™ Pathogens:
- Mixed infections:
• Gram-negative bacilli (Pseudomonas, Klebsiella, Proteus, E.
coli,). Pseudomonas (most common aerobe)
• Staphylococcus aureus
o Anaerobes “anaerobic Streptococci ( most common anaerobe)
and Bacteroides fragilis “

™ Risk Factors:
1. Abnormal Eustachian tube function:
o Cleft palate
o Down syndrome
2. Immune deficiency
3. Ciliary dysfunction:
o Kartagener syndrome.
4. Gastroesophageal reflux

™ Clinical presentation:
o Otorrhea (mucopurulent, odorous)
o TM perforation
o Inflamed middle ear mucosa
o Conductive hearing loss

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™ Types of CSOM:
- Clinically, it is divided into two types:

1. Tubo-tympanic TT:
- Safe type.
- Involves Antero-inferior part of middle ear cleft (Eustachian tube and
Mesotympanum).
- Central perforation.
- No risk of serious complications.

2. Attico-antral AA:
- Unsafe type
- Involves Postero-superior part of middle ear cleft (Attic, Antrum and
mastoid).
- Attic or Marginal perforation.
- Associated with a bone-eroding process such as Cholesteatoma,
Granulations or Osteitis.
- High risk of serious complications.

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¾ Tubotympanic CSOM:

- Mucosal disease of middle ear cleft with no evidence of invasion of

squamous epithelium.

- Active disease:
o Perforation of pars tensa with inflammation of mucosa and
mucopurulent discharge.

- Inactive disease:
o Permanent perforation of pars tensa but middle ear mucosa is
not inflamed and there is no discharge.
o Permanent perforation implies that squamous epithelium on the
external surface of pars tensa and mucosa lining its inner
surface have fused across its edge.

- Healed chronic otitis media:

o Adhesive otitis media.
o Healed TM (usually by two layers), atrophic and easily retracted
if there is negative pressure in the middle ear.
o Also have patches of Tympanosclerosis in tympanic membrane,
or in middle ear involving promontory, ossicles, tendons of
stapedius and tensor tympanic.
o Fibrotic tissue may appear in middle ear.
o Always associated with some degree of conductive hearing loss.

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- Etiology:
o Starts in childhood and is therefore common in that age group.
1. Sequel of Acute otitis media:
o Following fever and leaving behind a large central perforation.
o Perforation becomes permanent and permits repeated
infection from the external ear.
o Middle ear mucosa is exposed to the environment and gets
sensitised to dust, pollen and other aeroallergens causing
persistent otorrhoea.
2. Ascending infections via the eustachian tube:
o Infection from tonsils, adenoids and infected sinuses may be
responsible for persistent or recurring otorrhoea.
o Ascending infection to middle ear occur more easily in the
presence of infection.
3. Persistent mucoid otorrhoea is sometimes the result of allergy to
ingestants.

- Pathology:
o Disease localized to the mucosa.
o Mostly involves Antero-inferior part of the middle ear cleft.
o Processes of healing and destruction, depending on the virulence of
organism and resistance of the patient.
o Acute exacerbations are common.

- Pathological changes seen in Tubotympanic CSOM:

1. Perforation of pars tensa:
o Central perforation
o Size and position varies.
2. Middle ear mucosa:
o Normal when disease is inactive.
o Edematous when disease is active.
3. Polyp:
o Smooth mass of edematous and inflamed mucosa protruded
through a perforation and presents in the external canal.
o Pale (Pink, fleshy polyp seen in Attico-antral CSOM).

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4. Ossicular chain:
o Intact and mobile.
o May show some degree of necrosis (particularly long
process of incus).
5. Tympanosclerosis:
o Results from chronic inflammation or trauma
o Hyalinisation and calcification of subepithelial connective
tissue.
o Seen in remnants of TM or under the mucosa of middle ear.
o White chalky deposit on the promontory, ossicles, joints,
tendons and oval and round windows.
o Tympanosclerotic masses may interfere with the mobility of
these structures and cause CHL.
6. granulation tissue
7. Fibrosis and Adhesions:
o Long-standing eustachian tube dysfunction Result of healing
process ,
o May impair mobility of ossicular chain or block the
eustachian tube erosion of the long process of the incus and
the stapes suprastructure.

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- Clinical Features:
1. Ear discharge
o Non-offensive, mucoid or mucopurulent, constant or
intermittent.
o Appears mostly at time of URTI or on accidental entry of water
into the ear.
2. Hearing loss
o CHL
o Severity varies but rarely exceeds 50 dB.
o Patient reports of a paradoxical effect (hears better in the
presence of discharge than when the ear is dry) due to "Round
window shielding effect" produced by discharge which helps to
maintain phase differential.
o In the dry ear with perforation, sound waves strike both the
oval and round windows simultaneously, thus cancelling each
other's effect.
o In long standing cases, cochlea may suffer damage due to
absorption of toxins from the oval and round windows and
hearing loss becomes Mixed type.
3. Perforation
o Always central, it may lie anterior, posterior or inferior to the
handle of malleus.
o Small, medium or large or extending up to the annulus, i.e.
subtotal.
4. Middle ear mucosa
o Seen through large perforation.
o Normally, it is pale pink and moist.
o When inflamed it looks red, oedematous and swollen.
o Polyp may be seen.

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- Investigations:
1. Examination under Microscope:
o Essential in every case
o Provides useful information regarding :-
- Granulations
- Growth of squamous epithelium from the edges of
perforation
- Status of ossicular chain
- Tympanosclerosis
- Adhesions.
o An ear which appears dry may show hidden discharge under the
microscope.
o Rarely, cholesteatoma may co-exist with a central perforation
and can be seen under a microscope.

2. Audiogram:
o Assess degree of hearing loss and its type.
o Usually, CHL but a sensorineural element may be present.
o Decreased in the low frequencies in a small perforation and in
the high and low frequencies in a large perforation.
3. Culture and sensitivity of ear discharge:
o To select proper antibiotic ear drops.
4. CT scan temporal bone:
o Mastoid is usually sclerotic but may be pneumatised with
clouding of air cells.
o No evidence of bone destruction.
o Presence of bone destruction is feature of Attico-antral disease.

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- Treatment of Tubotympanic CSOM:
- Aim of the management:
o Control infection
o Eliminate ear discharge
o Correct the hearing loss by surgical means.

1. Aural toilet:
o Remove all discharge and debris from the ear.
o Done by dry mopping with absorbent cotton buds, suction
clearance under microscope or irrigation (not forceful syringing)
with sterile normal saline.
o Ear must be dried after irrigation.

2. Ear drops:
o Ofloxacin ,Neomycin, polymyxin, chloromycetin or gentamicin
are used.
o Combined with steroids which have local anti-inflammatory
effect.
o To use ear drops, patient lies down with the diseased ear up,
antibiotic drops are instilled and then intermittent pressure
applied on the tragus for antibiotic solution to reach the middle
ear.
o This should be done three or four times a day.
o Acid pH helps to eliminate pseudomonas infection, and
irrigations with 1.5% acetic acid are useful.
o Care should be taken as ear drops are likely to cause
maceration of canal skin, local allergy, growth of fungus or
resistance of organisms.
o Some ear drops are potentially ototoxic ’ aminoglycoside
antibiotics and propylene glycol”

3. Systemic antibiotics:
o Role of systemic antibiotics in the treatment of CSOM is limited.
o Useful in Acute exacerbation of chronically infected ear “
refractory cases”
o When specific pathogens are found on culture

4. Precautions:
o Keep water out of the ear during bathing, swimming and hair
wash.
o Rubber inserts can be used.
o Hard nose-blowing can also push the infection from
nasopharynx to middle ear and should be avoided.

5. Treatment of contributory causes:

o Treat concomitantly infected tonsils, adenoids, sinuses and nasal
allergy.

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6. Surgical treatment:
o Aural polyp or granulations, if present, should be removed
before local treatment with antibiotics.
o It will facilitate ear toilet and permit ear drops to be used
effectively.
o Should NEVER be avulsed as it may be arising from the stapes,
facial nerve or horizontal canal and thus lead to facial paralysis
or labyrinthitis.

7. Reconstructive surgery:
o Once ear is dry, Tympanoplasty with or without ossicular
reconstruction can be done to restore hearing.
o Closure of perforation will also check repeated infection from the
external canal.
o Ideally, an ear with a tympanic membrane perforation should be
free from infection for 3 months before tympanoplasty.

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¾ Atticoantral CSOM:

- Squamosal disease of middle ear.

- Active disease:
o Presence of cholesteatoma of posterosuperior region of pars
tensa or in the pars flaccida.
o Erodes bone, forms granulation tissue and has purulent
offensive discharge.
- Inactive disease:
o Atelactatic ear.
o Retraction pockets in pars tensa (usually the posterosuperior
region) or pars flaccida.
o No discharge but there is a possibility of squamous debris in
retraction pockets to become infected and start discharging.
o Some retraction pockets are shallow and self cleansing.

- Atticoantral diseases is associated with the following

pathological processes:
1. Cholesteatoma
2. Osteitis and granulation tissue
o Osteitis involves outer attic wall and Postero-superior margin of
tympanic ring.
o Granulation tissue surrounds the area of osteitis and may even
fill the attic, antrum, posterior tympanum and mastoid can lead
to bone erosion “Collagenase”
o A fleshy red polypus may be seen filling the meatus.
3. Aural polyp
o Infected cholesteatoma sometimes manifests as an “aural polyp.
o These “polyps” are actually granulation tissue at the junction
between an eroding cholesteatoma and bone.
o The presence of an aural polyp in a chronically infected ear
should be considered to be a cholesteatoma until proven
otherwise

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4. Ossicular necrosis:
o Common in Atticoantral disease.
o Destruction may be limited to long process of incus or may also
involve stapes superstructure, handle of malleus or the entire
ossicular chain.
o Hearing loss is always greater than in disease of tubotympanic
type.
o Cholesteatoma may bridges the gap caused by the destroyed
ossicles, and hearing loss is not apparent (cholesteatoma
hearer).

5. Cholesterol granuloma:
o Mass of granulation tissue with foreign body giant cells
surrounding the cholesterol crystals.
o A reaction to long-standing retention of secretions or
haemorrhage, and may or may not co-exist with cholesteatoma.
o When present in the mesotympanum, behind an intact drum,
the TM appears blue.

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- Symptoms
1. Ear discharge:
o Usually scanty, patient may not even be aware of it.
o Always foul-smelling due to bone destruction.
o Total cessation of discharge from an ear which has been active
till recently should be viewed seriously, as perforation in these
cases might be sealed by crusted discharge, inflammatory
mucosa or a polyp, obstructing the free flow of discharge.
o Pus, in these cases, may find its way internally and cause
complications.
2. Hearing loss:
o Hearing is normal when ossicular chain is intact or when
cholesteatoma, having destroyed the ossicles, bridges the gap
caused by destroyed ossicles (cholesteatoma hearer).
o Mostly CHL
o Evidence suggests that sensorineural hearing loss (SNHL) can
result from chronic otitis media with or without cholesteatoma
3. Bleeding:
o From granulations or the polyp when cleaning the ear.

- Signs:
1. Perforation:
o Either Attic or Postero-superior marginal type.
o Small attic perforation may be missed due to presence of a
small amount of crusted discharge.
o Sometimes, the area of perforation is masked by a small
granuloma.
2. Retraction pocket:
o Invagination of tympanic membrane is seen in the attic or
Postero-superior area of pars tensa.
o Degree of retraction and invagination varies.
o In early stages, pocket is shallow and self-cleansing.
o Later, pocket is deep and accumulates keratin mass and gets
infected.
3. Cholesteatoma:
o Pearly-white flakes of cholesteatoma can be sucked from the
retraction pockets.

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- Investigations:
1. Examination under microscope:
o All patients of chronic middle early disease should be examined
under microscope.
o Suction clearance and examination under Microscope forms an
important part of clinical examination of any type of CSOM.
o May reveal & assess
- Cholesteatoma “site and extent”
- Evidence of bone destruction
- Granuloma
- Condition of ossicles
- Pockets of discharge.
2. Tuning fork tests and audiogram:
o Pre-operative assessment and to confirm degree and type of HL.
3. CT scan temporal bone:
o Indicate extent of bone destruction and degree of mastoid
pneumatisation.
o Useful to indicate a low-lying dura or an anteposed sigmoid
sinus when operation is being contemplated on a sclerotic
mastoid.
o Cholesteatoma causes destruction in the area of attic and
antrum (key area).
4. Culture and sensitivity of ear discharge:
o Helps to select proper antibiotic for local or systemic use

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- Complications of COM with cholesteatoma in order of
frequency:
1. HL “conductive, sensorineural, mixed type” – Ossicular chain
disruption in up to 30%
2. Inner Ear Fistula – 10% of cases, mainly HSCC, rarely Cochlea
3. Extradural or Perisinus Abscess
4. Labyrinthitis – Serous or Suppurative
5. Facial Nerve Paralysis – Acute (infection) or Chronic (slow
expansion)
6. Meningitis secondary to Tegmen Erosion
7. Subdural or Intraparenchymal Brain Abscess
8. Sigmoid Sinus Thrombosis/Phlebitis
9. Subperiosteal Abscess/Bezold’s Abscess due to erosion of Mastoid
Cortex
10. Recurrent Cholesteatoma

- Features Indicating Complications in CSOM

1. Pain:
o Uncommon in uncomplicated CSOM.
o Considered serious as it may indicate extradural, perisinus or
brain abscess.
o Otitis externa associated with a discharging ear.
2. Vertigo:
o Erosion of lateral semicircular canal which may progress to
labyrinthitis or meningitis.
o Fistula test should be performed in all cases.
3. Persistent headache:
o Intracranial complication.
4. Facial weakness:
o Erosion of facial canal.
5. A listless child refusing to take feeds and easily going to sleep:
o Extradural abscess.
6. Fever, nausea and vomiting:
o Intracranial infection.
7. Irritability and neck rigidity:
o Meningitis.
8. Diplopia:
o Gradenigo's syndrome.
9. Ataxia:
o Labyrinthitis or cerebellar abscess.
10.Abscess around the ear:
o Mastoiditis.

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Cholesteatoma:

- Cystlike, “epidermal inclusion cysts” expansile lesions of the temporal

bone lined by stratified squamous epithelium “ matrix” that contain
desquamated keratin.
- Presence of keratinising squamous epitheliumin in the middle ear or
mastoid (Skin in the wrong place) .

- Normally, middle ear cleft is lined by different types of epithelium in

different regions.
o Ciliated columnar in the anterior and inferior part.
o Cuboidal in the middle part
o Pavement-like in the attic.
o No where lined by keratinising squamous epithelium.

- The term cholesteatoma is a misnomer:

o It neither contains cholesterol crystals nor is it a tumour to
merit the suffix "oma".
o The term has been retained because
of its wider usage.
o It has also been named Epidermosis
or Keratoma.

- Cholesteatoma consists of two parts:

1. Matrix:
o Made up of keratinising squamous
epithelium resting on a thin stroma
of fibrous tissues.
2. Keratin mass:
o Central white mass consisting of
keratin debris produced by the
matrix.

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315
- Pathology
- Cholesteatomeas may develop anywhere within pneumatized portions
of the temporal bone, with the most frequent locations being the
middle ear and the mastoid.
- Matrix composed of fully differentiated squamous epithelium resting on
connective tissue
- Deep layers: Down-growth into connective tissue
- Granulation tissue contacts bone; elaborates collagenase causing:-
- bone destruction
- Infection
- otorrhea,
- hearing loss
- facial nerve paralysis,
- labyrinthine fistula
- intracranial complications “epidural and subdural abscesses,
parenchymal brain abscesses, meningitis, and thrombophlebitis of
the dural ,venous sinuses”

- Only cholesteatoma and TM epithelium migrate

- In human temporal bones with chronic otitis media, cholesteatoma

was observed in 36% of ears with perforations and in 4% of ears
without the perforated tympanic membranes

- Cholesteatoma debris is a favourable medium for bacteria and

Aspergillus.

o Most common aerobic bacteria

ƒ Pseudomonas aeruginosa.
ƒ Staphylococcus aureus
o Most common anaerobic microorganisms are anaerobic cocci
ƒ Peptococcus/Peptostreptococcus
ƒ Bacteroides
ƒ Proteus,
ƒ Enterobacter
ƒ aerobic and anaerobic nonhemolytic streptococci,.
ƒ diphtheroid bacilli

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- Mechanisms of Bone erosion (faster in active infection):
1. Mechanical: Pressure from expansile mass.
2. Biochemical:
- Bacterial (Endotoxins)
- Granulation tissue Products (Collagenase and Acid
hydrolase)
- Substance related to cholesteatoma itself (Growth
factors, Cytokines).
3. Cellular:
- Osteoclastic activity (Acid phosphate, Acid Proteases
,Collagenase other protolytic enzymes)
- Osteocytes – BMP-2, TGF beta
- Macrophages – ILs -1, -6, -11; TNF-α, TGF-α, PGs, LTs,
PTHrP, CSF-1, OPF

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- Classification of Cholesteatoma:
1. Congenital
2. Acquired, Primary.
3. Acquired, Secondary.

Congenital Cholesteatoma:
- Theory:
o Arises from Embryonic epithelial cells rests in the middle ear
cleft or temporal bone.
o Failure of involution and continued growth of the Epidermoid
Formation, derived from 1st branchial groove ectoderm
o Found at junction of Eustachian tube orifice and middle ear near
anterior tympanic annulus
o Normally disappears in 33rd week of gestation
o Other theories:- include Ectodermal migration, and Metaplasia
of the middle ear mucosa

- Occurs at three important sites and produces symptomatology

depending on its location.
o Middle ear
o Petrous apex
o Cerebellopontine angle.
- 2/3 of cases are seen as white mass in Anterior-superior quadrant.
- Mean age 4.5 years.
- 3:1 Male to Female

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318
- Levenson Criteria for Congenital Cholesteatoma
1. White mass Medial to Intact TM
2. Normal pars flaccida & tensa.
3. No History of TM Perforation or Discharge.
4. No History of Trauma or Surgery
5. Prior otitis media is NOT an exclusion

- Congenital cholesteatomas staging system ‘Potsic and others”

1. Stage I: Limited to one quadrant
2. Stage II: Involving multiple quadrants without ossicular involvement
3. Stage III: Ossicular involvement without mastoid extension
4. Stage IV: Mastoid involvement.
- There is a correlation between stage and risk of residual disease
- IV 67% risk of residual cholesteatoma after surgical resection

- It causes CHL.
- Sometimes discovered on routine examination of children or at the
time of myringotomy.
- It may also spontaneously rupture through the tympanic membrane
and present with a discharging ear indistinguishable from a case of
chronic suppurative otitis media (CSOM).

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319
Acquired Cholesteatoma:
- The common factor of all acquired cholesteatomas is that the
keratinizing squamous epithelium has grown beyond its normal limits.

9 Two types of Acquired Cholesteatoma

o Primary Acquired:
o AKA Retraction Pocket cholesteatoma
o NOT secondary to infection, develop within a retraction pocket
o Secondary Acquired:
o Secondary to perforation from infection, surgery or trauma

- Acquired Primary Cholesteatoma:

- NOT associated with pre-existing perforation.
1. Invagination Theory (Retraction pocket)( Wittmaack) :
o Prolonged Eustachian tube obstruction.
o Persistent Negative pressure in Middle ear.
o Poor pneumatization of Epitympanum and Attic.
o Invagination of TM from the Pars Flaccisa (due
to lack of fibrous layer) or Postero-Superior part of pars tensa
in the form of Retraction pockets.
o Once a retraction pocket develops, the normal migratory pattern
of the tympanic membrane epithelium is altered, enhancing the
potential accumulation of keratin.
o As the retraction pocket deepens, desquamated keratin cannot
be cleared from the recess, and a Cholesteatoma results
o Infection has no rule in the development of cholesteatoma.

2. Basal cell hyperplasia Theory:

o Modification of invagination theory.
o Cone-like extension of the basal layer of
epidermis can become invasive as a result of
infections.
o Microcholestatoma arise as prickle cells invade
the subepithelial layer through breaks in the
basal lamina.
o Expanding cholesteatoma then breaks through pars flaccida
forming an attic perforation.

- Patients with cleft palate , long stand OME tend to develop Primary
Acquired Cholesteatoma due to ET Dysfunction

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320

1231
Riyadh et al. Notes
321

9 Sadý & Berco stages of middle ear atelectasis

o Stage I – Retraction
o Stage II – Severe retraction (against ISJ)
o Stage III – Atelectasis (against Promontory)
o Stage IV – Adhesive Otitis media

’Nonpneumatized mastoids may have a limited ability to buffer

pressure changes and can manifest as an atelectasis, a retraction
pocket, or a cholesteatoma’

1232
322
Riyadh et al. Notes
323
Acquired Secondary Cholesteatoma:
- There is already a pre-existing perforation in pars tensa from
infection, surgery or trauma

1. Epithelial invasion (Migration) Theory:

o Most accepted theory.
o Keratinized stratified squamous epithelium from the meatus or
outer drum surface grows into the middle ear through a pre-
existing perforation especially of the marginal type where part
of annulus tympanicus has already been destroyed.

2. Implantation Theory:
o Iatrogenic implantation of skin into TM or middle ear.
o Caused by Surgery “myringotomy for ventilating tube,” FB or
Blast injury
o Or arise from a perforation as a result of Acute Necrotic OM in
childhood.

3. Metaplasia Theory:
o Transformation of columnar epithelium to keratinized stratified
squamous epithelium.
o Secondary to Chronic or recurrent OM.
o Not believed to be an explanation for a significant cause of
cholestatoma formation in humans.

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324

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Riyadh et al. Notes
325

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326
- Surgical Anatomy:
- Cholesteatomas of the epitympanum start in Prussak’s space.
o Small pocket bounded by:
o Laterally: Pars Flaccida.
o Medially: Neck of the Malleus.
o Superiorly: Lateral malleolar fold.
o Inferiorly: Lateral process of Malleus.

- Most common locations of origin of Primary Acquired

Cholesteatoma

1. Posterior Epitympanum. “ commonest” “In pars flaccida or attic “

2. Posterior Mesotympanum. “posterosuperior quadrant of pars tensa”
3. Anterior Epitympanum.

- (Hypotympanum is rarely involved by Cholesteatoma)

The most common sites for this primary acquired cholesteatoma are pars flaccida or attic (being less fibrous and less resistance to
displacement) and posterosuperior quadrant of pars tensa. The attic perforation is simply the proximal end of an expanding
invaginated sac.

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Riyadh et al. Notes
327
- Posterior Epitympanic route:
- Most common spread pattern.
- Originates in Prussak’s space, breaks out by either penetrating
1) Posterior into Superior Incudal space and into Aditus
and Mastoid
2) Inferiorly into Posterior Pouch of von Troltsch (Between
TM and post mal fold)
3) Anteriorly into Anterior Pouch of von Troltsch

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Riyadh et al. Notes
328
- Posterior Mesotympanic route:
- Second most common spread pattern.
- Pars tensa retracts
- Allows cholesteatoma to gain access to the regions of the
o Stapes
o Round window
o Sinus tympani
o Facial recess

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329
- Anterior Epitympanic route:
- Cholesteatomas form Anterior to the malleus head.
- Easily overlooked during tympanomastoidectomy if the area is not
explored.
- Cholesteatomas may involve the Facial nerve.
- Extend into Anterior pouch of von Troeltsch “Between TM and anterior
mallear fold”
- Into Supratubal recess.
o Also called Anterior Epitympanic recess.
o Anteriorly: Middle cranial fossa, Petrous tip, Root of zygoma
o Posteriorly: Cog, extending to the cochleariform process
o Superiorly: Middle cranial fossa
o Floor: Associated with the horizontal portion of the facial nerve.
o Laterally: Tympanic bone and chorda tympani nerve.

- Most common location for residual cholesteatoma after surgery:

1. Sinus tympani.
2. Facial recess.
3. Anterior Epitympanium(protympanum)
4. Sinodural angle / mastoid tip ( check list)

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331
™ Prevention of Cholesteatoma Formation
- Retraction pocket is due to Prolonged Eustachian tube dysfunction.
o Precedes the development of acquired cholesteatoma
o Most pockets extend into epitympanum or sinus tympani.
o Good practice to aggressively manage such retraction pockets
- Long-term tympanostomy tube should be placed to
o Resolve the negative middle ear pressure.
o Allows the tympanic membrane to revert to a neutral position.

- TM has been retracted for a long time, loses all its elasticity, it will not
revert to a normal appearance.
- If the retraction pocket is adherent to the ossicles or folds or if it has
been present for an extended period of time, the retraction pocket will
persist.
- If the retraction pocket persists, surgical exploration may be indicated.

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Riyadh et al. Notes
332
™ Patient Evaluation

- History:
- Early symptoms of cholesteatoma:
o Hearing loss ( first )
o Otorrhea
o Otalgia
o Nasal obstruction
o Tinnitus
o Vertigo.

- A previous history of middle ear disease, CSOM or tympanic

membrane perforation may be revealed.
- Progressive unilateral CHL with a chronic foul smelling otorrhea should
raise suspicion.
- some are asymptomatic

- Examination:

- Diagnosis of cholesteatoma is made on otoscopic examination that

includes:
o Endoscopic
o Microscopic evaluation
o Surgical exploration

- Microscope:
o Important for evaluating the presence of cholesteatoma.
o Ear should be thoroughly cleaned of otorrhea and debris.
o Attic or Postero-superior quadrant Retraction pocket.
o Granulation tissue from diseased bone of the scutum or
posterior bony wall.
o Polyp may protrude through an Attic defect.
o If the disease is very extensive, the entire attic and mastoid
antrum will be filled with granulation tissue, and the underlying
bone will become necrotic and friable over a wide area.
o Extreme caution should be used with polyp removal as it may be
adherent to important underlying structures such as the ossicles
or facial nerve.

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333
- Pneumatic Otoscopy:
o Positive fistula (pneumatic otoscopy will result in nystagmus and
vertigo) response suggests erosion of the semicircular canals or
cochlea.
- Cultures should be obtained with wet, infected ears.
o Topical and/or oral antibiotics should be administered in these
cases.

- Audiological evaluation:
- PTA with air and bone conduction, speech reception thresholds, and
word recognition:
o CHL in the affected ear varies depending on extent of disease.
o Moderate CHL deficit in excess of 40 dB indicates ossicular
discontinuity, usually from erosion of the long process of the
incus or capitulum of the stapes.
o Mild CHL may be present with extensive disease if the
cholesteatoma sac transmits sound directly to the stapes or
footplate.
o Small perforation: CHL in the low frequencies.
o Large perforation: CHL in both high and low frequencies.

- Tympanometry results will vary and may suggest decreased

compliance or perforation of the tympanic membrane.
- Audiometry results should always be correlated with the 512Hz tuning
fork exam.

- Radiological investigations:
- CT Temporal bone:
o 1mm -section without contrast in axial and coronal planes.
o Allows for evaluation of anatomy, extent of the disease and as
screen for complications.
o Scutum erosion, Antrum expansion, Ossicular destruction,
Tegmen, HSCC or CN VII dehiscence
-
- Diffusion-weighted MRI Temporal bone:
o T1: HYPOintense.
o T2: HYPERintense.
o FLAIR: Intermediate in signal.

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334
™ Management:
- Cholesteatoma must come out surgically unless:
o Too old or too sick “ unfit”
o Small and easily accessible not infected cholesteatoma to
suction clearance under operating microscope
o Risks of surgery may not outweigh the benefits in some patients
with only-hearing ears.
o Patients refusing surgery.

- Manage medically first in the clinic:

o Serial Meticulous suction cleaning
o Remove All attic crusts
o Remove polyps clinic (never avulse them out)
o Topical Antibiotics drops
o Irrigation with 2% acetic acid in 20% isopropyl alcohol may
keep some cholesteatomas stable

- Surgical intervention:
- Dry ears are much easier to operate on than wet, infected ears.
- While it is not always possible to dry a chronically infected ear with
medical therapy

- Preoperative counseling:
- Absolute necessity prior to surgery.
- Primary objective of surgery is Safe dry ear
- Which is accomplished by:
o Aeration of the middle ear
o Treating all complications
o Removing diseased bone, mucosa, granulation polyps, and
cholesteatoma
o Preserving as much normal anatomy as possible ( posterior
canal wall) & closure of the middle ear

- Secondary objective of surgery is Hearing improvement.

- Possible adverse outcomes must be discussed including:

o Facial paralysis
o Vertigo
o Further hearing loss
o Tinnitus.
o Recurrent and residual cholesteatoma
o CSF leak and meningitis.
o Mastoid cavity: Need for cleaning and water precautions.
- Patient should understand that long-term follow-up debridement every
6 to 12 months will be necessary and that they may need additional
surgeries “second-stage procedures for residual cholesteatoma or
ossicular chain reconstruction”.

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Riyadh et al. Notes
335

- Surgical Management:
- Mainstay of treatment.
- Factors affecting choice of surgery
- Local factor
ƒ Extent of disease
ƒ Fistula
ƒ ET function
ƒ Pneumatization of mastoid
ƒ Hearing level in both ears
- General factor
ƒ General medical condition
ƒ Occupation
ƒ Reliability
- Skill and experience of the surgeon

- The surgical procedure to be used should be designed for each

individual case according to the extent of disease.
- More extensive disease will usually dictate a more aggressive surgical
approach.

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336
Riyadh et al. Notes
337
™ Types of Mastoidectomy are done to deal with cholesteatoma:
o Cholesteatoma limited to the middle ear can be managed with a
tympanoplasty.
o The status of the ossicular chain must be meticulously evaluated
o Cholesteatoma can be removed without disrupting the ossicular
chain.
o If the lateral chain, malleus and incus, are significantly involved
with cholesteatoma, the surgeon should consider separating the
incus from the stapes and remove the incus.
o If cholesteatoma medial to the head of the malleus, the surgeon
should also consider removing the head of the malleus.
o If Cholesteatoma that is adherent to the stapes can be
meticulously removed with microinstrumentation or laser.
o Extensive granulation tissue. significant bleeding, or an exposed
facial nerve in the tympanic segment near the stapes, the
surgeon should consider leaving some cholesteatoma on the
stapes and attempt to remove it at a second look procedure.
o Exteriorization of cholesteatomas without complete removal lead
to:
x Progressive hearing loss
x Chronically draining ears

o Types of Mastoidectomy

- Canal-wall-up (Intact wall):

o Simple mastoidectomy “ Cortical Mastoidectomy “
o Complete mastoidectomy with and without a facial
recess approach “Posterior tympanotomy”

- Canal-wall-down:
o Radical mastoidectomy
o Modified radical mastoidectomy (MRM)
o Bondy MRM
- Other:
o Atticotomy ( transcanal)
o Canal wall reconstruction
o Mastoid obliteration

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338
o Indications Mastoid Surgery
1. Persistent or recurrent otorrhea.
2. Persistent or recurrent ear pain.
3. Conductive hearing loss
4. TM perforation and/or cholesteatoma.
5. Acute mastoiditis with osteitis.
6. Neoplasm of temporal bone.
7. Fracture of temporal bone with CSF leak.
8. Facial nerve paralysis requiring decompression of the facial
nerve.
9. Various other surgical procedures such as:
o Cochlear implantation
o Labyrinthectomy
o Endolymphatic sac decompression
o Accessing the cerebellopontine angle, skull base, and
petrous apex

o Cortical Mastoidectomy (Simple Mastoidectomy):

- Sometimes called a Transmastoid antrotomy
- A CWU approach to exenterate:
o Mastoid cortex
o All accessible mastoid air cells
o Entering the antrum
- Good for drain acute mastoid infections that are refractory to ABx
“mastoiditis with subperiosteal abscess “.

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Riyadh et al. Notes
339
o Canal wall up (CWU) Mastoidectomy (Intact canal
mastoidectomy):
- More complete removal of the air cell system than simple
mastoidectomy
- Avoid the problems and maintenance necessary of CWD procedures.
- Consists of preservation of the posterior bony external auditory canal
wall during simple mastoidectomy:
- Without posterior tympanotomy (Complete Mastoidectomy)
- With posterior tympanotomy (Facial recess approach)
performed through a triangle bounded by the fossa incudis,
facial nerve, and chorda tympani nerve.

- A staged procedure is often necessary with a scheduled second look

operation at 6 to 18 months for removal of residual cholesteatoma
and ossicular chain reconstruction if necessary.
- Recent variations on canal-wall-up mastoidectomy include removing
a portion of the canal wall then reconstructing the defect with bone,
cartilage, or an alloplastic material.

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Riyadh et al. Notes
340

- This approach may be indicated in patients with:

- Large pneumatized mastoid
- Well aerated middle ear space,
- Good eustachian tube function.

- Contraindications of CWU: (FUSION ET)

1. Labyrinthine Fistula & other complication
2. Unfit for second look , Unsuccessful previous mastoidectomy
(residual/recurrent cholesteatoma)
3. Sclerotic mastoid
4. Involvement Posterior canal wall (Automastoidectomy)
5. Only hearing ear.
6. Non-compliant to follow-up.
7. Poor ET function.

- Advantages
o Maintaining normal anatomy (Physiologic TM and deep middle
ear space)
o Rapid healing
o Avoidance of mastoid cavity. ( No need for frequent care and
water precautions)
o Hearing aids are easier to fit and wear.

- Disadvantages
o Incomplete exteriorization of facial recess.
o Residual disease more likley
o Recurrent Cholesteatoma may occur in Attic
o Need for mandatory Second look
o Delayed canal breakdown

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Riyadh et al. Notes
341
- Rates of cholesteatoma recurrence after CWU mastoidectomy:
o Residual: 20-35%
o Recurrence: 5-20%
o Just remember “30 & 15%”

o Canal wall down (CWD) Mastoidectomy:

- Taking down the superior & posterior canal wall to the level
of the vertical facial nerve and exteriorizing the mastoid into
the external ear canal (one cavity).
- Epitympanum is obliterated with removal of the
ƒ Scutum
ƒ Head of the malleus
ƒ Incus.
- Meatoplasty should be large enough to allow good aeration of
the mastoid cavity and permit easy visualization to facilitate
postoperative care and self cleaning.

- Modified Radical Mastoidectomy:

- A classic CWD operation in which the middle ear space is
preserved.
- To eradicate disease of attic and mastoid.
- TM remnant, functioning ossicles and the reversible mucosa
and function of the eustachian tube are preserved.
- Ossicular reconstruction , tympanoplasty can also be
performed
- Indications:
1. Cholesteatoma confined to the attic and antrum.
2. Localised chronic otitis media.

- Postoperatively, cavity is fully epithelialised in 2-3 months.

- Should be periodically checked (every 4-6 months) in the
first year and then annually for removal of any debris or
infection.
- Any granulation tissue which delays epithelialisation is
removed or cauterised.

- Radical mastoidectomy:
- CWD operation in which the middle ear space is eliminated
and the eustachian tube is plugged.
- To eradicate disease of the middle ear and mastoid with
complete removal of TM, annulus, malleus, incus and middle
ear mucosa “stapes is usually preserved”
- Opening of eustachian tube is plugged with piece of muscle
or cartilage aiming for a dry "open" cavity with no secreting
epithelium “entire cavity becomes lined with squamous
epithelium”
- Rarely required these days.

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Riyadh et al. Notes
342
- Indicated in these situations:
1. When all cholesteatoma cannot be safely removed, e.g.
that invading eustachian tube, round window niche,
perilabyrinthine or hypotympanic cells.
2. Disease tracking into the petrous apex
3. Removal of glomus tumour.
4. Carcinoma middle ear. Radical mastoidectomy followed
by radiotherapy is an alternative to en bloc removal of
temporal bone in carcinoma middle ear.

- Bondy Modified Radical Mastoidectomy

- Rarely used today.
- Bondy procedure is performed like the modern modified
radical mastoidectomy with the exception that the middle ear
space is not entered.
- Removal of the scutum and portion of the posterior canal
wall to exteriorize the antrum and epitympanum
- Preservation of the ossicles and middle ear space
- The bony defect is not reconstructed; rather, the
cholesteatoma matrix is exteriorized.

- Indication:
o Attic cholesteatoma that does not involve the middle
ear space and is lateral to the ossicles , accompanied
by a sclerotic mastoid

- Indications of CWD: (FUSION ET)

1. Labyrinthine Fistula & other complicaion “cholesteatoma over
the labyrinth simply becomes part of the epithelial coverage of
the mastoid cavity”
2. Unfit for second look , Unsuccessful previous mastoidectomy
(residual/recurrent cholesteatoma)
3. Sclerotic mastoid
4. Involvement Posterior canal wall (Automastoidectomy)
5. Only hearing ear.
6. Non-compliant to follow-up.
7. Poor ET function.

- Advantages of CWD:
o Easy to assess for residual disease
o Lower incidence of recurrent disease
o Total exteriorization of facial recess.
o Second look surgery is not mandatory.
o Cost effective

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Riyadh et al. Notes
343
- Disadvantages of CWD:
o Delayed healing (Risk of failure to epithelize)
o Altered anatomy
o Implication of Mastoid cavity “frequent episodes Discharge”
(requires periodic microdebridement and water precautions for
rest of patient’s life)
o Shallow middle ear space is difficult to reconstruct.
o Greater difficulty achieving Hearing Improvemen

- Rates of cholesteatoma recurrence after CWD mastoidectomy:

o Residual: 2-17%
o Recurrence: 0-10%
o Just remember “10 & 5%”

- Five things to do in surgery during Modified Radical

Mastoidectomy to ensure Dry ear:
1. Complete Saucerization of mastoid cavity (remove all mucosa)
2. Lower the Facial Ridge to the level of the facial nerve “remove
any Dependent Spaces”
3. Take down the Mastoid Tip
4. Cavity Obliteration with Fat or Muscle (Palva flap or Temporalis
Muscle)
5. Wide Meatoplasty

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Riyadh et al. Notes
344

o Transcanal Anterior Atticotomy

- Elevation of a tympanomeatal flap via an endaural incision
- Removal of the scutum to the limits of the cholesteatoma.
- After removal of the disease, the aditus is obliterated with muscle,
fascia, cartilage or bone prior to reconstruction of the middle ear
space.
- Some advocate reconstruction of the lateral attic wall “ scutum site”
with bone or cartilage, however, this may lead to retraction disease
and possible recurrence in patients with poor eustachian tube function.

- Indication:
o Limited cholesteatoma involving the middle ear, ossicular chain,
and epitympanum.

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Riyadh et al. Notes
345
o MASTOID OBLITERATION
o Mastoid obliteration is typically used when the canal wall has been
removed to decrease the size of the mastoid cavity and make it as
care free as possible.
o Extent of mastoid air cell obliteration vary considerably from
surgeon to surgeon.
o Various materials are used that include :-
o Autogenous bone paté, bone chips and cartilage, free or
vascularized soft tissue,
o "Paiva flap” postauricular musculoperiosteal flap that
was rotated inward to obliterate the mastoid cavity , can
use of bone chips and bone paté in combination with the
flap
o “Hong Kong flap” temporalis muscle flap or temporalis
fascia flap based on a superficial temporal artery pedicle

o Alloplastic hydroxylapatite , tricalcium phosphate , ceramic

materials “ more infection “

o In rare cases, the eustachian tube and external ear canal are
closed to completely isolate the mastoid from the exterior “
Blind sac”
o The radiographic features suggestive of disease recurrence after
mastoid obliteration have not been well studied

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Riyadh et al. Notes
346
o Canal-wall reconstruction (CWR)
o Developed to improve exposure and removal of cholesteatoma as in
a CWD approach while retaining the benefits of an intact canal wall
- improved hearing
- avoidance of the mastoid cavity

o Complete mastoidectomy including a facial recess is performed and

the posterior canal is removed.
o The cholesteatoma. the ossicles, and the tympanic membrane are
addressed, and the posterior canal wall is replaced.
o Can be done with or without mastoid obliteration

o Meatoplasty
o Enlarging the external auditory meatus is a necessary part of canal-
wall-down procedures.
- Promotes aeration and epithelialization of the canal and cavity
- Facilitates effective postoperative caree debridement much
easier.
- Reduces the depth of the cavity

o Several techniques to meatoplasty have been advised “All involves

removing some concha cartilage and draping the posterior meatal skin
into the mastoid cavity”

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Riyadh et al. Notes
347

o Meatoplasty can be performed by:-

- Connecting superior and inferior Lempert endaural incisions with the
postauricular incision.
- The superior cut is brought out laterally into the tragal incisura while
the inferior cut is curved just medial to the antitragus.
- Varying amounts of this cartilage can be removed (through the
postauricular incision), thin concha skin that drapes into the mastoid
bowl )

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348
- Causes of a Draining Cavity Post Mastoidectomy
o Surgical factors:
1. Recurrent or residual disease
2. Inadequate meatoplasty
3. Defect in tympanic membrane remnant
4. Poor mastoid shape
5. High facial ridge
6. Nooks and crannies
7. Deep mastoid sump
o Patient factors:
1. Poor mastoid care (poor compliance with follow-up
appointments)
2. Inadequate water precautions
3. Inadequate toilet
4. Hearing aid wear

o Monitoring the mastoid for cholesteatoma extremely important.

o If cholesteatoma is left behind in the mastoid cavity, or trapped
underneath a mastoid obliteration, intracranial or vascular
complications can occur even many years after the initial
procedure.
o Diffusion-weighted MRI scans have given the otologic surgeon a
noninvasive mechanism to evaluate a patient's mastoid for
recidivistic cholesteatoma with fairly high accuracy

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Riyadh et al. Notes
349
o SURGICAL TECHNIQUE: MASTOIDECTOMY

- Incisions
- The two principal incisions used:
1. Postauricular incision of Wilde
2. Endaural incision of Lempert.

- Postauricular incision provides better overall exposure and allows

complete access to the mastoid tip.
- In adults
o Incision is placed 8 to 10 mm posterior to the postauricular
sulcus
o It can be placed more posteriorly for wider exposure as might
be necessary during translabyrinthine access to the
cerebellopontine angle.
o Should not be placed directly in the postauricular crease
because such placement creates a deep, difficult clean
- In children younger than 2 years
o The inferior portion of this incision must be placed more
posteriorly than in adults
o Because the tympanic ring in children is underdeveloped,
mastoid pneumatization is incomplete, and the stylomastoid
foramen is shallow. Avoid facial nerve injury.

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Riyadh et al. Notes
350

- Postauricular incision is first outlined with a marking pen and 5 to 10

ml infiltrated with a mixture of local anesthetic and epinephrine
“postauricularly and within the external ear canal”
- Skin and subcutaneous tissues are incised sharply down to the
temporalis fascia (superior to the inferior temporal line) and down to
the periosteum overlying the mastoid cortex (inferior to the inferior
temporal line).

- Elevated anteriorly to identify the posterior edge of the external ear

canal.
- Elevation superior to the ear canal exposes the root of the zygoma.
- Dissection is carried to the mastoid tip “not to dissect anterior to the
tip because this endangers the facial nerve in the stylomastoid
foramen “.
- Periosteum of the mastoid cortex is Incised with a "T" -shaped or an
"L” shaped Incision.
- The periosteum is elevated off the mastoid cortex toward the posterior
margin of the ear canal now exposed to start the drilling process

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351
- Self-retaining retractors should now be placed to hold the auricle
forward
- Suprameatal spine of Henle marks the lateral extent of the posterior-
superior bony ear canal.
- Two anteriorly flaps:
- (a) The pinna and subcutaneous tissues
- (b) The deeper musailope riosteal tissues.
- Both layers should be closed to maintain a patent meatus and a
properly positioned auricle.

- Endaural incisions
- Expose a limited portion of the mastoid cortex.
- First, a posterior canal wall incision is made from the 12-o'dock to the
6-o' dock position just medial to the bony cartilaginous junction
(Lempert I incision).
- From the 12-o'clock position of the Lempert I incision, a medial-to
lateral incision is made into the incisura between the tragus and root
of the helix (Lempert II incision).
- A relaxing incision is then made at the inferior maigin of the Lempert I
incision (in a medial-to-lateral direction)
- This allows the posterior ear canal and conchal skin to be mobilized
- Skin, soft tissues, muscle. and periosteum over the mastoid cortex are
elevated using Lempert elevators, and a self-retaining retractor ia
placed.

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Riyadh et al. Notes
352

- Indications of this incision:

o Simple mastoidectomy in very poorly pneumatized temporal bones
o Atticotomies,
o Canaloplasty
o Some tympanoplasty

- Surface Landmarks
o Inferior temporal line (linea temporal is) defines the inferior limit of
the temporalis muscle “level of the floor of the middle cranial
fossa”.
o Suprameatal spine of Henle is Inferior to the temporal line
o Macewen triangle (cribrose area) is a depressed pit just posterior to
the spine of Henle “landmark for the underlying mastoid antrum”
o Antrum ia typically located 15 mm medial to the cribrose area
“dome of the horizontal semicircular canal (HSCC) along its floor”
o Zygomatic root is palpable anterior-superior to the ear canal.
o The anterior- inferior, and posterior-inferior walls of the atemal
auditory canal are formed by the tympanic bone
o Posterior-superior bony ear canal “between the tympanasquamous
and tympanomastoid suture lines” made of squamous bone “thicker
and more vascular skin “

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Riyadh et al. Notes
353
o Children younger than 2 years have :-
x Immature tympanic rings
x Poorly pneumatization mastoids ,stylomastoid foramen is
shallow
x In children or adults with canal atresia, mal-development of the
tympanic bone may result in facial nerve exit directly from the
mastoid cortex

- When the mastoid cortex fully exposed:

o First bur cut is made along the temporal line “which
approximates the level of the middle cranial fossa dural plate”.
o Second bur cut is made perpendicular to this and tangential to
the external bony canal; it should be carried inferiorly to the
mastoid tip

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Riyadh et al. Notes
354

- As the antrum is approached, it is essential to widely saucerize toward

the tegmen and especially posteriorly, from the sinodural angle to the
mastoid tip.
- Posteriorly, consider the sigmoid sinus, which could be far forward in a
poorly pneumatized mastoid.
- Dissection is carried medially, and the antrum is approached, a bony
septum (Körner septum)
- Opening the antrum too inferiorly, can injure the HSCC, the genu of
the facial nerve, or both.
- Identifying the short process of the incus provides an important
landmark for facial nerve will be 1 to 2 mm deeper.

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Riyadh et al. Notes
355
- Surgical landmarks of CN VII through the Middle Ear
o Horizontal SCCs
o Cochleariform process lie just anterior – VII runs posterior &
above this
o Short process of the Incus – Marks the beginning of the Second
Genu & VII runs medial to it
o Fossa incudis
o Digastric Ridge – Anterior extent of ridge leads to Stylomastoid
foramen
o Chorda Tympani
o Oval Window
o Cog
o Pyramidal eminence

“Always safer to define the location of this structure than

simply to avoid it”

1264
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356

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Riyadh et al. Notes
357
- OPENING THE FACIAL RECESS performed through a triangle
bounded by the
1. Fossa incudes “superiorly” “small depression ,below the aditus is
a, the, which houses the short process of the incus and its
suspensory ligament “
2. Facial nerve “ medially “
3. Chorda tympani nerve “laterally”

o Recess provides access to the middle ear from the mastoid

“promontory, round window niche, stapes, long process of the
incus, cochleariform process, medial side of the tympanic
membrane and malleus handle, and Eustachian tube all are well
visualized.”
o Facial recess can be extended superiorly and inferiorly to provide
a large “posterior tympanotomy.”

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Riyadh et al. Notes
358

1267
Riyadh et al. Notes
359

- OPENING THE EPITYMPANUM

o In CWU surgery, it is often necessary to expose the epitympanum.
o Cholesteatoma can track medially to the heads of the ossicles and
can extend into the anterior epitympanic space “epitympanic recess
“supratubal recess”
o Incus remnant and the head of the malleus are removed to
provide good access into the anterior aspect of the epitympa

1268
Riyadh et al. Notes
360

- CANAL-WALL-DOWN MASTOIDECTOMY
o Saucerization cortical edges of the cavity are taken down to the
approximate level of the tegmen superiorly, sigmoid sinus
posteriorly, and digastric ridge inferiorly
o The facial nerve is positively identified by removing the posterior
bony canal until only a thin shell of bone remains over the nerve.

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Riyadh et al. Notes
361
o This dissection is continued toward the stylomastoid foramen until
no bony spur remains (inferior or posterior buttress) between the
floor of the external bony canal and the mastoid cavity.
o Anterior extent of the superior canal wall (anterior buttress) is
completely removed to create a smooth, gently curving transition
from the anterior epitympanum to the anterior canal wall.
o Ideally, the contours of the cavity itself should be smooth, without
bony recesses or overhangs.
o Small amounts of bone plate collected during saucerization of the
cortical edges can be used to fill irregularities within the cavity.
o Obliteration of these areas, however, should not be performed if
the surgeon is not confident that all cholesteatoma remnants have
been thoroughly removed.
o Last, a large meatus ensures adequate ventilation of the mastoid
cavity and appropriate access for postoperative cleaning.
o Meatoplasty to create a properly sized meatal opening.

- Follow-up
o Healing of mastoid cavity if present
o Healing of surgical wound
o Resolution of presenting symptoms

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Riyadh et al. Notes
362
- ENDOSCOPY
o Endoscopes often see where the microscope cannot
o 1.7- to 2.8-mm, 0 or 30-degree rigid telescope,
o Can visualize the facial recess, sinus tympani, or epitympanum
o Can be used to assess the depth of retraction pockets and
determine the extent of cholesteatomas.
o Some surgeons use it for second-look procedures.

- ENDOLYMPHATIC SHUNT
o Endolymph in the inner ear may flow from the cochlea to the
endolymphatic sac.
o "shunt" or "decompress' endolymphatic sac for the treatment of
intractable Menere disease
o Successful control of vertigo has been reported in a majority of
patients
o Exposure of the endolymphatic sac require CWU mastoidectomy &
open of facial recess
o Endolymphatic sac comes into view just posteroinferior to the posterior
semicircular canal.
o Place a sickle knife or similar instrument into the sac and palpate the
operculum

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Riyadh et al. Notes
363
- PETROUS APICECTOMY
o Surgical access to the petrous apex.
o Becomes necessary for:
x Drainage of infected air cells “Petrositis (petrous apicitis)
“Petrous Apex Syndrome”
x Cholesteatomas (congenital)
x Cholesterol granulomas and mucosal cysts
x Biopsy of various mass lesions
ƒ Benign tumors
x Meningioma
x Schwannoma
ƒ Malignant tumors
x Chondrosarcoma / Chondroma
x Chordroma
x Plasmacytoma
x Metastatic lesion
x Langerhans cell histiocytosis

o The petrous apex takes the form of a truncated pyramid in the

posterior skull base
o Oriented anteromedially between occipital and sphenoid bones
o Forms part of the foramen lacerum

o Petrous bone may be of three types (like mastoid),:

1. Pneumatised with air cells extending to the petrous apex “Posterior
Petrous Apex pneumatized in 30%, Anterior Petrous Apex
pneumatized in 10%”
2. Diploic containing only marrow space
3. Sclerotic.

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Riyadh et al. Notes
364
o Petrous apex divided into Anterior/Posterior by plane running through
IAC or Cochlea”:
1. Anterior Petrous apex: medial to cochlea, Larger, Consists of
bone marrow or air cells.
2. Posterior Petrous apex: medial to SCC, Smaller, dense bone

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Riyadh et al. Notes
365

o Petroclinoid ligament Extending from the tip of the petrous apex to the
clinoid.
o The abducens nerve travels below the petroclinoid ligament in a small
canal called the Dorello canal.

o Air cell tracts extend to the apex below, above, posterior, and anterior
to the labyrinth
o Direct extension of infection from the mastoid and middle ear through
pneumatized air-cell tracts into the petrous apex

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Riyadh et al. Notes
366
o Access to the petrous apex depends on the specific anatomy:
o May be obtained via the retrolabyrinthine infracochlear, or
subarcuate air cell tracts.
o Most patients, the petrous apex can be drained via a CWU
approach to the temporal bone.
o Some may be necessary to perform a canal wall down
mastoidectomy or possibly a middle cranial fossa approach to
access this area
o Typically, the margins of the exposure include the cochlea
superiorlythe carotid artery anteriorly, and the internal jugular
vein and bulb posteriorly.

o Surgical approach to the petrous apex depends on:

1. Available air-cell pathways “below, above, posterior, and
anterior to the labyrinth”
2. The portion of the apex involved “posterior, and anterior”
3. Hearing , non-hearing ear “Sparing the otic capsule surgically is
preferred in patients with serviceable hearing “

o The classic procedures designed to access the posterior petrous

apex include:
1. Infralabyrinthine approach
2. Translabyrinthine approach “Sinodural”
3. Retrolabyrinthine approach
4. Subarcuate “provide drainage via cells that extend over the
superior semicircular canal and through the “hole in the
doughnut,” working through the center of the superior
semicircular canal”

o Procedures used to access the anterior petrous apex include:

1. Infracochlear approach.
2. Transotic approach “ FN not mobilized”
3. Transcochlear approach “ transposition of FN”
4. Middle fossa approach: Used when the disease involves the
anteriorpettous apex but spares the middle ear and mastoid.
5. Anterior approach through the glenoid fossa: Described by
Ramadier and was popularized by Lempert. The exposure
involves removal of the anterior canal wall and condyle of the
mandible; exposure of the epitympanum; avulsion of the tensor
tympani; opening of the tensor semicanal; and then dissection
in the triangle between the carotid artery (posterior), the
cochlea (superior), and the middle fossa dura (anterior). This
approach can be modified by preserving the anterior canal wall
and condyle.))

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Riyadh et al. Notes
367
6. Endoscopic Trans-sphenoidal: the presence of venous sinuses
between the petrous apex and sphenoid, such as the cavernous
sinus, can make this approach challenging. It can be considered
for lesions located in the medial section of the petrous apex
abutting and/or prolapsing into the posterior wall of the
sphenoid sinus.

o In a non-hearing ear (Passing through Otic capsule):

o Translabyrinthine
o Transcochlear (Transotic) approach
o Provides superior access for complete removal of mass lesions
o One disadvantage of these two approaches is that they could
potentially expose the cerebrospinal fluid (CSF) to the infectious
process.

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368

1277
Riyadh et al. Notes
369

1278
Riyadh et al. Notes
370
Reconstructive Surgeries:

1. Myringoplasty:
- Surgical procedure limited to TM reconstruction only.
- Simple Closure (Paper Patch) Technique:
o Considered for small perforations.
o Requires “Rimming” the perforation (Freshening the
edges) to stimulate regrowth.
o Subsequent placement of a scaffold material to encourage
cellular migration (eg, Cotton disk, onionskin paper,
cigarette paper, silastic film, or collagen film).
- Graft Technique:
o Repair of TM utilizing a tissue graft.
o Graft material of choice:
1. Temporalis fascia (Most common).
2. Perichondrium.
3. Periosteum.
4. Cartilage.
5. Dura.
6. Vein.
7. Fat

- Graft repair can be done by two techniques:

1. Medial (Underlay) Technique:
o Margins of perforation are freshened.
o Graft placed under Annulus and remnant TM and either
over or under malleus.
o Supported by gelfoam in the middle ear.
o Used for Most TM perforations.
o Difficult with large anterior perforation.
o High graft take rate.
o Less risk of graft blunting
o Easy technique.
o Short OR time.
o Less complication
2. Lateral (Overlay) technique:
o Margins of perforation are freshened.
o Graft is placed lateral to Annulus and medial to malleus.
o Used for Larger perforations (especially Ant. perforation).
o Gives Excellent exposure.
o High graft take rate.
o Longer OR time.
o Longer healing process.
o Risk of lateralization and anterior blunting of graft.
o Risk of entering glenoid fossa.
o Greater postoperative CHL

1279
Riyadh et al. Notes
371

2. Tympanoplasty:
- Operation to:
1. Exploration of Middle ear and eradication of disease.
2. Reconstruction of middle ear.

- TM epithelium shed in a centrifugal direction from the umbo.

- From the physiology of hearing mechanism, the following principles

can be deduced to restore hearing surgically:
1. Intact tympanic membrane:
o Provides large hydraulic ratio between the tympanic membrane
and stapes footplate.
2. Ossicular chain:
o Conducts sound from tympanic membrane to the oval window.
3. Two functioning windows:
o Oval window on the scala vestibuli (to receive sound vibrations).
o Round window on the scala tympani (to act as a relief window).
o If it is only one window, as in stapes fixation or closure of round
window, there will be no movement of cochlear fluids resulting
in conductive hearing loss.
4. Acoustic separation of two windows:
o Sound does not reach both the windows simultaneously.
o Achieved by providing an intact tympanic membrane,
preferential pathway to one window (usually the oval) by
providing ossicular chain and by the presence of air in the
middle ear.
5. Functioning eustachian tube:
o Provides aeration to the middle ear.
6. Functioning sensorineural apparatus (cochlea and CN-VIII).

1280
Riyadh et al. Notes
372
- Wullstein Classification of Tympanoplasty:

1. Type I:
o Perforation of TM only.
o Repaired with a graft to intact ossicular
chain.
o Also called Myringoplasty.

2. Type II:
o Perforation of TM + Erosion of Malleus.
o Repaired with a graft placed on Incus or
remnant of malleus.

3. Type III:
o Perforation of TM + Erosion of Malleus +
Incus.
o Repaired with a graft placed on Stapes
Suprastructure.
o Also called Myringostapediopexy or
Columella Tympanoplasty.

4. Type IV:
o Perforation of TM + Erosion of Malleus +
Incus + Stapes Suprastructures.
o Only mobile footplate of Stapes is present.
o Repaired with a graft placed on mobile
stapes footplate.

5. Type V:
o Stapes footplate is fixed.
o Type A:
- Graft to Horizontal SCC after fenestration.
o Type B:
- Graft to Oval window after Stapedctomy.

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Riyadh et al. Notes
373
3. Ossiculoplasty:
- Ossicular Chain Reconstruction (OCR).
- Required when there is destruction or fixation of ossicular chain.
- Reestablishes sound conduction mechanism from TM to inner ear fluids
- Ossicular disruption most commonly occurs at Incudostapedial joint
secondary to necrosis of the lenticular process (most susceptible site
of avascular necrosis).

o Most common causes of Malleus Head Fixation

- Otosclerosis
- Tympanosclerosis
- Postinfectious
- Congenital fixation
- Trauma?

- Incus Replacment Prosthesis:

o Short prosthesis with notch.
o Malleus (+)
o Stapes (+)

- Incus-Stapes Replacment Prosthesis:

o Long prosthesis with notch.
o Malleus (+)
o Stapes (-)

- Partial Ossicular Replacement Prosthesis (PORP):

o Short prosthesis without notch.
o Malleus (-)
o Stapes (+)

- Total Ossicular Replacement Prosthesis (TORP):

o Long prosthesis without notch.
o Malleus (-)
o Stapes (-)

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Riyadh et al. Notes
374
- Incus Replacement Techniques
1. Transposed or Sculptured Incus Autograft:
o Incus is removed, resculptured, and placed between the malleus
and the stapes suprastructure
2. Homograft:
o Well tolerated.
o Provides excellent sound conduction.
o May be presculpted
o Requires storage
o Risk of disease transfer.
3. Synthetic Incus Strut:
o Constructed from a variety of materials (eg, titanium,
hydroxyapatite, porous polyethylene).
o Recreate the connection from the malleus to the stapes
suprastructure.
4. Partial Ossicular Replacement Prosthesis (PORP):
o Replaces malleus and incus.
o Connect the TM to the stapes capitulum.
o Constructed from a variety of material (eg titanium,
hydroxyapatite, porous polyethylene with a cartilagenous cap)
- Incus-Stapes Replacement Techniques
1. Transposed or Sculptured Incus Autograft:
o Incus is removed, resculptured, and placed between the malleus
and the stapes footplate.
2. Homograft:
o Well tolerated.
o Provides excellent sound conduction.
o May be presculpted
o Requires storage
o Risk of disease transfer.
3. Synthetic Incus-Stapes Strut:
o Constructed from a variety of materials (eg, titanium,
hydroxyapatite, porous polyethylene).
o Recreate the connection from malleus to the stapes footplate.
4. Total Ossicular Replacement Prosthesis (TORP):
o Replaces malleus, incus and staped suprastructures
o Connect the TM to the stapes footplate.
o Constructed from a variety of material (eg titanium,
hydroxyapatite, porous polyethylene with a cartilagenous cap).

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375
- Most common ossicular fixations:
- Ankylosis of stapes footplate:
o Otosclerosis.
o Corrected by removal of the fixed stapes and its replacement by
a prosthesis.
- Fixation of head of malleus in attic:
o Congenital or acquired.
o Corrected by removal of the head of malleus and entire incus
and then establishing contact between handle of malleus and
the stapes.

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Riyadh et al. Notes
376
Ossiculoplasty
Ossicular Chain Reconstruction (OCR)

- Required when there is Discontinuity or Fixation of ossicular chain.

- Ossicular disruption most commonly occurs at Incudostapedial joint
secondary to necrosis of the lenticular process (most susceptible site of
avascular necrosis).

¾ Austine classification:

Group A
o Malleus (+)
o Stapes (+)

Group B
o Malleus (+)
o Stapes (-)

Group C
o Malleus (-)
o Stapes (+)

Group D
o Malleus (-)
o Stapes (-)

¾ Kartush added three more classes as a modification of this scheme in

include ossicular fixity even when all three ossicles are present.

O - Intact ossicular chain

E - Ossicular head fixation

F - Stapes fixation

1285
Riyadh et al. Notes
377
¾ The Middle ear Risk index (Kartush ) “determined parameters for OCR
outcome”

9 Otorrhea
o Dry 0
o Occasionally wet 1
o Persistently wet 2
o Wet, cleft palate 3

9 Perforation
o Absent 0
o Present 1

o Cholesteatoma
o Absent 0
o Present 1

o Ossicular status
o M+ I+ S+ 0
o M+ S+ 1
o M+ S- 2
o M- S+ 3
o M- S- 4

o Malleus head fixation

Absent 0
Present 1

o Stapes fixation
Absent 0
Present 3

o Granulations or effusion
o No 0
o Yes 1

o Previous surgery
None 0
Staged 1
Revision 2

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Riyadh et al. Notes
378
- Incus Replacment Prosthesis:
o Short prosthesis with notch.
o Malleus (+)
o Stapes (+)

o In case Erosion of incudo-stapedial joint only

o Can use Applebaum or Titanium prosthesis
o Or
o Remove the incus and treat as M+S+ defect

- Incus-Stapes Replacment Prosthesis:

o Long prosthesis with notch.
o Malleus (+)
o Stapes (-)

1287
Riyadh et al. Notes
379
- Partial Ossicular Replacement Prosthesis (PORP):
o Short prosthesis without notch.
o Used when the stapes superstructure is present
o Connect the TM to the stapes capitulum
o Malleus (-)
o Stapes (+)

- Total Ossicular Replacement Prosthesis (TORP):

o Long prosthesis without notch.
o Used when the stapes superstructure is abcent
o Connect the TM to the footplate
o Malleus (-)
o Stapes (-)

1288
Riyadh et al. Notes
380
- Incus Replacement Techniques
1. Transposed or Reshape Incus Autograft:
o Incus is removed, reshape, and placed between the malleus and the
stapes suprastructure

2. Homograft:
o Well tolerated.
o Provides excellent sound conduction.
o Requires storage
o Risk of disease transfer.
3. Synthetic Incus Strut:
o Constructed from a variety of materials (eg, titanium, hydroxyapatite,
porous polyethylene).
o Recreate the connection from the malleus to the stapes
suprastructure.

4. Partial Ossicular Replacement Prosthesis (PORP):

o Replaces malleus and incus.
o Connect the TM to the stapes capitulum.
o Cartilage graft is placed between the PORP and tympanic membrane to
reduce the chance of extrusion ( except hydroxyapatite )
o Constructed from a variety of material (eg titanium, hydroxyapatite,
polyethylene ,plastipore with a cartilagenous cap)

1289
Riyadh et al. Notes
381

- Incus-Stapes Replacement Techniques

1. Transposed or Reshape Incus Autograft:
o Incus is removed, reshape, and placed between the malleus and the
stapes footplate.

2. Homograft:
o Well tolerated.
o Provides excellent sound conduction.
o Requires storage
o Risk of disease transfer.
3. Synthetic Incus-Stapes Strut:
o Constructed from a variety of materials (eg, titanium, hydroxyapatite,
polyethylene).
o Recreate the connection from malleus to the stapes footplate.

1290
Riyadh et al. Notes
382
4. Total Ossicular Replacement Prosthesis (TORP):
o Replaces malleus, incus and staped suprastructures
o Connect the TM to the stapes footplate.
o cartilage graft is placed between the TORP and tympanic membrane to
reduce the chance of extrusion ( except hydroxyapatite )
o Constructed from a variety of material (eg titanium, hydroxyapatite,
polyethylene ,plastipore with a cartilagenous cap)

- Most common ossicular fixations:

- Ankylosis of stapes footplate:
o Otosclerosis.
o Corrected by stepedetomy ,stepedecomy and its
replacement by a prosthesis.
- Fixation of head of malleus in attic: most common
o Congenital fixation
o Acquired (Otosclerosis ,,Tympanosclerosis ,, Postinfectious ,,
surgical Trauma temporal bone fracture )
o Corrected by removal of the head of malleus and entire incus
and then establishing contact between handle of malleus
and the stapes.
- Isolated Fixation of the incus
- Combined fixation of the malleus and incus

1291
Riyadh et al. Notes
383

¾ Situation 1
9 Mobile stapes
o Removal and reshaped incus
o Synthetics (Alloplast) incus Strut

9 Fixed stapes
o Incus Replacement with Stapedotomy (IRS)
x Single stage if tympanic membrane
x 2nd stage if perforated

¾ Situation 2
9 Mobile stapes
o Removal and reshaped incus
o Synthetic Incus-Stapes Strut

9 Fixed stapes
o Incus - Stapes Replacement with Stapedotomy
x Single stage if tympanic membrane
x 2nd stage if perforated

¾ Situation 3
9 Mobile stapes : PORP
9 Mobile footplate :- TORP
9 Fixed:- Stapedotomy + TORP

1292
 Riyadh et al. Notes
384
Types of material according to the host reaction

Bio-incompatible Bio-compatible
Induce FB reaction with fibrosis, giant cell
reaction and rejection

(Polyethylene, teflon)

Bio-active
The host tissue react favorably with the implant to Bio-inert
promote soft tissue attachment Induce no reaction
( Bone, Cartilage, Hydroxyapatite, Titanium) ( Silastic, Plastipore)

¾ Prosthetic materials
• Natural Grafts “bone “ (Autograft, allograft):
Advantages
• Biocompatible
• Good sound conduction
• Cheap
• Available
Disadvantages
• May harbor disease
• Osseous fixation ( can placed in direct contact with cochlea )
• Requires time & skill
• Transmits disease , Storage requirement (allograft)

• Synthetics (Alloplast):
• Advantages
• Ready made (save time)
• Easy storage
Disadvantages
• Variable bio-compatibility
x Plastipore®
o Easy to trim
o Bio-Inert unless placed in direct contact with TM
o No osseos fixation “

x Hydroxyapatite
o Compatible if placed against TM with no cartilage
o Osseous fixation
o Not easy to trim

1293
Riyadh et al. Notes
385
x Titanium
o Osseous fixation
o Light and strong
o Easy to handle
o Needs cartilage interposition

¾ Criteria of the ideal material

– Bio-compatible
– Shape – size ,weight
– Efficient sound conduction
– Maintains results over time
– Resists and tolerates infection
– Easy to use
– cost

¾ What are the reasons for OCR failure ?

9 Disease :- recurrent , residual

9 Prosthesis failure :-
oExtrusion ( improper size , design flow)
oMovement ( at lateral or medial connection )
9 Surgeon factor

1294
Riyadh et al. Notes

Complications of Otitis Media 386

™ Factors Influencing Development of Complications
x 1. Age
9 Most of the complications occur in the first decade of life or in the
elderly when the patient's resistance is low.
x 2. Poor socio-economic group
9 Several factors play an important part. such as :
a. overcrowding
b. poor health education (lack of awareness about middle ear
discharge is still being considered merely a nuisance rather
than a potentially dangerous condition)
c. poor personal hygiene
d. limited access to health care
x 3. Virulence of organisms
9 Many organisms are developing resistance to antibiotics
9 Acute infections are either not controlled or progress to subacute or
chronic otitis media.
9 Insufficient dose, less effective drug or insufficient period of
administration of antibiotic can cause complications.
9 Streptococcus pneumoniae type III (earlier called pneumococcus
type III) is very virulent due to production of autolysin and
pneumolysin.
9 H. influenzae ,Pseudomonas , MRSA is developing resistance to β-
lactam antibiotics .

x 4. Immune-compromised host
9 Patients suffering from AIDS, uncontrolled diabetes, transplant
patients receiving immunosuppressive drugs, cancer patients
receiving chemotherapy are more prone to develop complications.
x 5. Preformed pathways
9 Infection can easily travel beyond the middle ear cleft if
preformed pathways exist like :-
o Dehiscence of bony facial canal,
o previous ear surgery
o fracture of temporal bone
o stapedectomy,
o perilymph fistula
o congenitally enlarged aqueduct of vestibule (as in Mondini's
abnormality of inner ear)
o dehiscence in the floor of middle ear.
x 6. Cholesteatoma
9 Osteitis or granulation tissue in chronic otitis media destroy the
bone and help infection to penetrate deeper.
9 In acute and chronic middle ear infection, disease process is limited
only to the mucoperiosteal lining of the cleft but if it spreads into
the bony walls of the cleft or beyond it, various complications can
arise.

1295
Riyadh et al. Notes

™ Pathways of Spread of Infection387

9 The most common pathway for infection to extend beyond the
mastoid is through the lateral cortex behind the ear.
9 Less commonly, it can extend to the soft tissues in the upper
portion of the neck (see the section on Bezold abscess)
9 rarely, to the soft tissue anterior and superior to the auricle
x 1. Direct bone erosion
9 In acute infections, it is the process of hyperaemic of bone
causes decalcification.
9 In chronic infection, it may be osteitis, erosion by cholesteatoma
or granulation tissue.
x 2. Venous thrombophlebitis
9 Veins of Haversian canals are connected with dural veins which
in turn connect with dural venous sinuses and superficial veins of
brain.

9 Thus, infection from the mastoid bone can cause

thrombophlebitis of venous sinuses and even cortical vein
thrombosis.
9 This mode of spread is common in acute infections.

x 3. Preformed pathways
x (i) Congenital dehiscences, e.g. in bony facial canal, floor of middle
ear over the jugular bulb.
x (ii) Patent sutures, e.g. petrosquamous suture.
x (iii) Previous skull fractures. The fracture sites heal only by fibrous
scar which permits infection.
x (iv) Surgical defects, e.g. stapedectomy, fenestration and
mastoidectomy with exposure of dura.
x (v) Oval and round windows.
x (vi) Infection from labyrinth can travel along internal acoustic
meatus, aqueducts of the vestibule and that of the cochlea to the
meninges.

1296
Riyadh et al. Notes

388
™ Classification
Complications of otitis media are classified into two main
groups
Extracranial Intracranial
Intratemporal 1. Extradural abscess or
1. Mastoiditis granulation tissue
a) Acute Mastoiditis 2. Subdural abscess
b) Coalescent 3. Meningitis
c) Masked (Latent) 4. Brain abscess
Mastoiditis 5. Lateral “ sigmoid” sinus
2. Petrositis thrombophlebitis
3. Facial Paralysis (Occluding ,Non
4. Labyrinthitis occluding)
5. Labyrinthine fistula 6. Otitic hydrocephalus.

Extratemporal
1. Subperiosteal abscess
associate with
mastoiditis
2. Inferior deep neck
abscess “Bezold’s
abscess” associate
with mastoiditis

1297
Riyadh et al. Notes

389

1298
Riyadh et al. Notes

390

x Complications secondary AOM are more common in young children

x Complications secondary to COM with and without cholesteatoma
are more common in older children and adults
x 78% of subjects who had complications secondary to COM were
found to have cholesteatoma
x Most common extracranial complication from COM &AOM “acute
mastoiditis with post auricular abscess “Subperiosteal abscess” ”
x 2nd most common extracranial complication from AOM facial palsy
x Most common intracranial complication from AOM & COM meningitis
x 2nd most common intracranial complication of otitis media Brain
abcess
x Typically, mastoiditis is the initial complication, with more severe
complications developing secondarily

1299
Riyadh et al. Notes

x Five early Signs of Impending 391 Complication

1. Persistence of acute infection for 2 weeks
2. Recurrence of symptoms within 2 weeks
3. Bad smell discharge during treatment
4. Acute exacerbation of chronic infection, especially if bad smell
5. Haemophilus influenzae type b or Anaerobes

x Once a complication has begun, signs and symptoms

typically progress rapidly:
1. Fever associated with a chronic perforation (intracranial infection or
extrac:ranial cellulitis)
2. Pinna displaced inferolaterally and/or edema of the posterosuperior
ear canal wall skin (subperiosteal abscess)
3. Retro-orbital pain (petrositis)
4. Vertigo in a patient with an infected ear (labyrinthitis or labyrinthine
fistula)
5. Facial paralysis ipsilateral to an infected ear (facial paralysis)
6. Headache and lethargy (intracranial complication of any sort)
7. Meningismus (meningitis or subdural abscess)
8. Focal neurologic signs or seizure (brain abscess)
9. Global neurologic signs (subdural abscess or meningitis)

1300
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392

1301
Riyadh et al. Notes

A. EXRACRANIAL COMPLICATIONS
393 OF OTITIS MEDIA

¾ Intratemporal
1. Mastoiditis
a. Acute Mastoiditis
b. Coalescent
c. Masked (Latent) Mastoiditis
2. Petrositis
3. Facial Paralysis
4. Labyrinthitis
5. Labyrinthine fistula
¾ Extratemporal
1. Subperiosteal abscess associate with mastoiditis
2. Inferior deep neck abscess “Bezold’s abscess” associate
with mastoiditis

1. (a) Acute Mastoiditis

9 Inflammation of mucosal lining of antrum and mastoid air cell

system is always accompaniment of acute otitis media and forms a
part of it.
9 The term "mastoiditis" is used when infection spreads from the
mucosa lining the mastoid air cells, to involve bony walls of the
mastoid air cell system result in breakdown of bony septa and
coalescence of air cells (acute coalescent mastoiditis)

™ Aetiology
9 Acute mastoiditis usually accompanies or follows acute suppurative
otitis media
9 Determining factors being:
o High virulence of organisms
o Lowered resistance of the patient due poor nutrition or associated
systemic disease such as diabetes.
9 Acute mastoiditis is often seen in mastoids with well-developed air
cell system.
9 Children are affected more.
9 Streptococcus pneumoniae is the most common offending pathogen
9 Other bacteria frequently implicated in acute mastoiditis include
Streptococcus pyogenes, Staphylococcus aureus, and Haemophilus
influenzae.
9 Anaerobic organisms are also associated with mastoiditis and need
antibacterial therapy against them.

1302
Riyadh et al. Notes

™ Pathology 394
9 Two main pathological processes are responsible:

x 1. Production of pus under tension.

x 2. Hyperaemic decalcification and osteoclastic resorption of bony
walls.

o Extension of inflammatory process to mucoperiosteal lining of air

cell system increases the amount of pus produced due to large
surface area involved.
o Drainage of this pus, through a small perforation of tympanic
membrane and/or eustachian tube, cannot keep pace with the
amount being produced.
o Swollen mucosa of the antrum and attic also impede the drainage
system resulting in accumulation of pus under tension.
o Hyperaemia of mucosa causes dissolution of calcium from the bony
walls of the mastoid air cells (hyperaemic decalcification).
9 Cause destruction and coalescence of mastoid air cells,
converting them into a single irregular cavity filled with pus
(Empyema of mastoid).
9 Pus may break through mastoid cortex leading to sub-periosteal
abscess which may even burst on surface leading to a
discharging fistula

1303
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395
™ Clinical Features

¾ Symptoms “similar to that of acute suppurative otitis media”

i. Pain behind the ear.
o Persistence & throbbing not subsides with establishment of
perforation or treatment with antibiotics.
ii. Fever.
o Persistence or recurrence of fever in a case of acute otitis
media, in spite of adequate antibiotic treatment that points to
the development of mastoiditis.
iii. Ear discharge
o Profuse and increases in purulence.
o In some cases, discharge may stop due to obstruction to its
drainage but other symptoms would worsen
o Any persistence of discharge beyond 2 weeks, in a case of
acute otitis media, points to mastoiditis.
¾ Signs
i. Mastoid tenderness.
o Over the middle of mastoid process, at its tip, posterior
border or the root of zygoma important sign.
o Tenderness elicited over the suprameatal triangle may not be
diagnostic of acute mastoiditis as it is seen even in cases of
the acute otitis media due to inflammation of mastoid antrum
(antritis).
o Tenderness should always be compared with that of the
healthy side.
ii. Ear discharge.
o Creamy Mucopurulent or purulent discharge, may be seen
coming through a central perforation of pars tensa.
iii. Sagging of posterosuperior meatal wall.
o It is due to periosteitis of bony party wall between the
antrum and deeper posterosuperior part of bony canal.
iv. Perforation of tympanic membrane.
o Usually, a small perforation is seen in pars tensa
o Sometimes, tympanic membrane is intact but dull and
opaque especially in those who have received inadequate
antibiotics.
o If the tympanic membrane is normal, the patient does not
have acute mastoiditis.

1304
Riyadh et al. Notes

v. Swelling over the mastoid. 396

o Initially, there is oedema of periosteum, imparting a smooth.
o Later retroauricular sulcus becomes obliterated and pinna is
pushed forward and downwards.
o When pus bursts through bony cortex, a subperiosteal
fluctuant abscess is formed

vi. Hearing loss. Conductive type of hearing loss is always present.

vii. General findings.
o Ill and toxic with low-grade fever.
o In children, fever is high with a rise in pulse rate.

1305
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397
™ Dx
o Diagnosis often is made clinical
o Contrasted CT of temporal bone
9 Coalescence or lack of septations between air cells in mastoid
with the presence of fluid or soft tissue
9 Should be done for patients presenting with mastoiditis
symptoms, to aid in therapeutic planning and to rule out other
possible complication
o Blood counts show polymorphonuclear leucocytosis
o ESR is usually raised.
o Ear swab for culture and sensitivity.

™ Differential Diagnosis
i. Suppuration of mastoid lymph nodes
o Scalp infection may cause mastoid lymph node enlargement and
then suppuration leading to abscess formation
o In such cases there is no history of preceding otitis media, ear
discharge or deafness.
o Abscess is usually superficial.

ii. Furunculosis of meatus

iii. Infected sebaceous cyst

1306
Riyadh et al. Notes

398
™ Treatment
o (a) Hospitalization of the patient

o (b) Antibiotics
9 Start with IV amoxicillin or ampicillin (in the absence of culture
and sensitivity).
9 Specific antimicrobial is started on the receipt of sensitivity
report.
9 Since anaerobic organisms are often present, metronidazole is
added.
o (c) Myringotomy
9 Relieved by wide myringotomy tubes & needle aspiration of
the abscess without formal drainage
9 Early cases of acute mastoiditis respond to conservative
treatment with antibiotics alone or combined with
myringotomy.
9 Less invasive than mastoidectomy
“experience, 14 of the 17 subjects treated in this manner
resolved their abscesses without the need for further
intervention, and were discharged home significantly sooner
than those subjects who were managed with a mastoidectomy”

o (d) Cortical mastoidectomy

9 Aim of cortical mastoidectomy is to exenterate all the
mastoid air cells and remove any pockets of pus granulations
It is indicated when there is:
9 The object of this operation is to drain the mastoid antrum
and air cells but leave the middle ear, the ossicles and the
external meatus untouched.
9 Indication:
1. Abscess resulting from chronic otitis in the presence of a
cholesteatoma “bcz no conservative alternatives”
2. Sagging of posterosuperior meatal wall.
3. Positive reservoir sign, i.e. meatus immediately fills with
pus after it has been mopped out.
4. No change in condition of patient or it worsens in spite of
adequate medical treatment for 48 hours.
5. Mastoiditis, leading to complications, e.g. facial paralysis,
labyrinthitis, intracranial complications.

9 Antibiotic treatment must be continued at least for 5 days

following mastoidectomy.

1307
Riyadh et al. Notes

399
™ Complications of Acute Mastoiditis
x 1. Subperiosteal abscess “ most common”
x 2. Labyrinthitis
x 3. Facial paralysis
x 4. Petrositis
x 5. Extradural abscess
x 6. Subdural abscess
x 7. Meningitis
x 8. Brain abscess
x 9. Lateral sinus thrombophlebitis
x 10. Otitic hydrocephalous.

™ Abscesses in Relation to Mastoid Infection

1308
Riyadh et al. Notes

o (a) Postauricular abscess 400

9 Commonest abscess that forms over the mastoid “extratemporal
complication”
9 Break through mastoid cortex leading to sub-periosteal abscess
which may even burst on surface leading to a discharging fistula
9 Can also occur as a result of vascular extension secondary to
phlebitis of the mastoid veins
9 More commonly in young children with AOM, also found in COM
with and without cholesteatoma
9 Pinna is displaced forwards, outwards and downwards.
9 In infants and children, abscess forms over the MacEwen's
triangle; pus in these cases travels along the vascular channels
of lamina cribrosa (mesh-like structures which allows nerve
fibres of the optic nerve to pass through the sclera).

1309
Riyadh et al. Notes

401
o (b) Zygomatic abscess
9 Occurs due to infection of zygomatic air cells situated at the
posterior root of zygoma.
9 Swelling appears in front of and above the pinna
9 There is associated oedema of the upper eyelid.
9 In these cases, pus collects either superficial or deep to the
temporalis muscle

o (c) Bezold abscess

9 Occur following acute coalescent mastoiditis when pus breaks
through the thin medial side of the tip of the mastoid and presents
as a swelling in the upper part of neck.
9 The abscess may:
o (i) Lie deep to sternocleidomastoid, pushing the muscle
outwards
o (ii) Follow the posterior belly of digastric and present as a
swelling between the tip of mastoid and angle of jaw
o (iii) Present in upper part of posterior triangle
o (iv) Reach the parapharyngeal space
o (v) Track down along the carotid vessels

1310
Riyadh et al. Notes

402
9 Clinical features of Bezold abscess:
o Onset is sudden.
o Present as a tender, fever, deep, poorly defined mass in level two
of the neck & torticollis.
o History of purulent otorrhoea.
o Because the abscess develops from air cells at the tip of the
mastoid, it is found in older children and adults
o A Bezold abscess should be differentiated from:

x Acute upper jugular lymphadenitis.

x Abscess or a mass in the lower part of the parotid gland.
x Infected branchial cyst.
x Parapharyngeal abscess.
x jugular vein thrombosis.

A CT scan of the mastoid and swelling of the neck may establish the
diagnosis” abscesses show a rim-enhancing abscess with surrounding
inflammation, may demonstrate the bony dehiscence in the tip of the
mastoid,and can help in operative planning” .

9 Treatment of Bezold abscess

1. Cortical mastoidectomy for coalescent mastoiditis with careful
exploration of the tip for a fistulous opening into the soft tissues of
the neck.
2. Drainage of the neck abscess “transcervical approach”
3. Intravenous antibiotics guided by the culture and sensitivity report
of the pus taken at the time of surgery.

1311
 Riyadh et al. Notes

403
o (d) Meatal abscess (Luc's abscess)
9 Pus breaks through the bony wall between the antrum and
external osseous meatus.
9 Swelling is seen in deep part of bony meatus.
9 Abscess may burst into the meatus.

o (e) Behind the mastoid (Citelli's abscess)

9 Abscess is formed behind the mastoid more towards the occipital
bone (compare postauricular mastoid abscess which forms over
the mastoid).

o (f) Parapharyngeal or retropharyngeal abscess

9 This results from infection of the peritubal cells due to acute
coalescent mastoiditis.

Sinodural angle, also called Citelli’s angle, is siuated between the sigmoid sinus and middle fossa dura plate.

1312
Riyadh et al. Notes

404
(b) Coalescent Mastoiditis

9 Implies breakdown and decalcification of the bony septa within the

mastoid,
9 Progressing to bony destruction of the cortex or other aspects of
the mastoid bone
9 If AOM and mastoiditis that persist for 2 to 4 weeks , coalescent
mastoiditis develops.
9 Typically affects boys, 4 years or younger with AOM. who have
previously well-aerated mastoids
9 Rarely occurs in the setting of COM , OR in children with poorly
pneumatized mastoids “sclerotic”
9 Up to 25% of patients presenting with coalescent mastoiditis will
have a concomitant intracranial complication

™ Aetiology
9 S. pneumoniae is the most common offending Organism
9 30% will culture positive for anaerobic organisms

™ Pathophysiology
9 Same above “ acute mastoiditis”

™ Clinical Features
9 Fever
9 Otalgia
9 purulent otorrhea
9 mastoid pain
9 tenderness
9 erythema, and/ or edema

™ Diagnosis.
9 CT: breakdown of bony septa. loss of cortical bone, and
opacification of the air cell system.
9 MRI: should be obtained if there is any suspicion of intracranial
complication.

1313
Riyadh et al. Notes

405
™ Treatment
9 It is serious medical problem that requires aggressive
9 Treatment, either surgical or medical.

9 Classically treatment “IV antibiotics + cortical mastoidectomy with

removal of necrotic, devitalized bone “

9 In recent years, “myringotomy + IV antibiotics 3 o 6 week

o Has been advocated as an alternative for surery
o This medical management requires a CT scan to confirm
resolution of the infection and aeration of the mastoid before
stop Abx

9 Cortical mastoidectomy + ventilating tube placement + IV

antibiotics
o Most conservative management of this potentially serious
complication
o Provides prompt, precise eradication of all infected tissue in an
expeditious
o Cost-effective manner.

1314
Riyadh et al. Notes

406

(c) Masked (Latent) Mastoiditis

9 Rare condition of slow destruction of mastoid air cells but without

the acute signs and symptoms often seen in acute mastoiditis.
9 There is no pain, no discharge, no fever and no mastoid swelling
9 Mastoidectomy may show extensive destruction of the air cells with
granulation tissue and dark gelatinous material filling the some
mastoid air cell.
9 May cause erosion of the tegmen tympani and sinus plate with an
extradural or perisinus abscess.

™ Aetiology
9 The condition often results from inadequate antibiotic therapy in
cases of acute otitis media when acute symptoms subside but
smouldering infection continues in the mastoid.
9 Middle ear & much of the mastoid respond to the antibiotics, but a
focal area in the mastoid persistent infection
9 Granulation or mucosal disease involves some mastoid air cells

™ Clinical Features
9 Patient is often a child
9 Not feeling well, with mild pain behind the ear but with persistent
hearing loss.
9 Tympanic membrane appears normal OR thick with loss of
translucency.
9 Slight tenderness may be elicited over the mastoid.
9 Audiometry shows conductive hearing loss of variable degree.
9 CT shows a localized area of opacification in an otherwise normal
mastoid & tympanic cavity.

™ Treatment
9 Cortical mastoidectomy with antibiotics
9 No different from the diagnosis and management of mastoiditis with
otorrhea that emanates from other causes

1315
Riyadh et al. Notes

(d) Chronic
407Mastoiditis

9 Implies chronic inflammation within the mastoid air cell system.

9 It can occur in typical COM with longstanding tympanic membrane

perforation, with cholesteatoma or as a complication from an
infection after placement of a middle ear ventilating tube.

9 Results in mucosal disease and/ or granulation tissue that causes

otorrhea to persist in spite of antibiotic therapy

9 Chronic mastoiditis usually results in sclerosis of the mastoid air cell

system commonly seen in CSOM

9 Mastoidectomy in either of these settings can be helpful in

eradicating otorrhea. ,, complete resolution with antibiotics is
unlikely

9 Differential diagnosis of chronic mastoiditis can be skull base

osteomyelitis “malignant otitis externa”

9 Complications in patients with chronic mastoiditis with tympanic

membrane perforation can develop at any time but often occur only
after weeks or months of otorrhea.

9 In contrast, cholesteatoma typically requires months or years to

produce complications.

1316
Riyadh et al. Notes

2. Petrositis (petrous apicitis)408 “Petrous Apex Syndrome”

9 Very rarely Spread of infection from middle ear and mastoid to the
petrous part of temporal bone “anterior, medial portion of the
temporal bone “is called petrositis.
9 The petrous apex takes the form of a truncated pyramid in the
posterior skull base
9 Anteromedially between occipital and sphenoid bones
9 Forms part of the foramen lacerum
9 Air cell tracts extend to the apex in continuity with the middle ear
and mastoid through well-described cell tracts below, above,
posterior, and anterior to the labyrinth, allowing for infection
involving the mastoid and middle ear cleft to extend into the
petrous apex

9 It may be associated with:

9 Acute coalescent mastoiditis
9 Latent mastoiditis
9 Chronic middle ear infections.

1317
Riyadh et al. Notes

™ Pathology 409
9 Petrous bone may be of three types (like mastoid),:
“Petrous apex divided into Anterior/Posterior by plane running
through IAC or Cochlea”

1. Pneumatised with air cells extending to the petrous apex “Posterior

Petrous Apex pneumatized in 30%, Anterior Petrous Apex
pneumatized in 10%”

2. Diploic containing only marrow space

3. Sclerotic.

o Petrous apex divided into Anterior/Posterior by plane running

through IAC or Cochlea”
1. Anterior Petrous apex: medial to cochlea ,,, Larger ,,Consists
of bone marrow or air cells.
2. Posterior Petrous apex: medial to SCC ,, Smaller ,, dense
bone

1318
Riyadh et al. Notes

410

1319
Riyadh et al. Notes

411
™ Clinical Features
9 Gradenigo's syndrome (secondary to forming epidural abscess at
the petrous apex)
9 Today, more commonly caused by Tumor at the Petrous Apex
(Cholesteatoma, Meningioma, etc)
9 The classical presentation, and consists of a triad of:
A. (Diplopia) external rectus palsy (VIth nerve palsy) occurs
from involvement of Dorello’s canal osteo fibrous canal
situated at the petrous apex containing the abducent nerve
& Inferior Petrosal sinus”

B. Deep-seated facial or retro-orbital pain (Trigeminal pain)

(Vth nerve involvement) “Trigeminal ganglion in the Meckel
cave”
C. Persistent ear discharge.

9 Persistent ear discharge with or without deep-seated pain in

spite of an adequate cortical or modified radical mastoidectomy also
points to petrositis.

9 Fever, headache, vomiting and sometimes neck rigidity may

also be associated.
9 Some patients may get facial paralysis and recurrent vertigo
, sensory hearing loss due to involvement CN VII, VIII, IX
9 Few patients had full triad today

1320
Riyadh et al. Notes

412
™ Diagnosis of petrous apicitis requires both CT scan and MRI
9 CT scan of temporal bone will show:
o Bony details of the petrous apex and the septa of air cells &
evaluate surrounding anatomy
o Provides important details about potential surgical routes
o Aid in the diagnosis of intracranial
o Asymmetry of the petrous apex is not diagnostic for apicitis,
because asymmetric pneumatization of the apex can occur in
healthy subjects.

9 MRI helps to differentiate diploic marrow containing apex from fluid

or pus, mucous.
9 Gallium bone scan may provide additional information, showing
increased uptake on the side of the apicitis

1321
Riyadh et al. Notes

413
9 Treatment
9 Petrous apex is an area that is not easily approached surgically
because of its relationship with the otic capsule and carotid artery.
9 Because of the difficult surgical approach and the response rate to
antibiotics

9 IV antibiotics are often the first-line treatment of petrous apicitis

o Most cases of acute petrositis can now be cured with
antibacterial therapy alone.
o Long duration of treatment.3-6 week
o Serial CRP & ESR rates to monitor for response of bony
infections
o Surgical drainage is required when presence abscess, necrotic
bone, or persistent infection despite medical therapy
o Should precede and follow surgical intervention

9 PETROUS APICECTOMY
o Surgical access to the petrous apex. becomes necessary for:-
x Drainage of infected air cells “Petrositis (petrous apicitis)
“Petrous Apex Syndrome”
x Cholesteatomas ( congenital )
x Cholesterol granulomas and mucosal cysts
x Biopsy of various mass lesions
ƒ Benign tumors
x Meningioma
x Schwannoma
ƒ Malignant tumors
x Chondrosarcoma / Chondroma
x Chordroma
x Plasmacytoma
x Metastatic lesion
x Langerhans cell histiocytosis

o Access to the petrous apex Depending on the specific anatomy

o May be obtained via the retrolabyrinthine infracochlear, or
subarcuate air cell tracts.
o Most patients, the petrous apex can be drained via a CWU
approach to the temporal bone.
o Some may be necessary to perform a canal wall down
mastoidectomy or possibly a middle cranial fossa approach to
access this area
o Typically, the margins of the exposure include the cochlea
superiorlythe carotid artery anteriorly, and the internal
jugular vein and bulb posteriorly.

1322
Riyadh et al. Notes

o 414 apex depends on:

Surgical approach to the petrous
1. Available air-cell pathways “below, above, posterior, and
anterior to the labyrinth”
2. The portion of the apex involved “posterior, and anterior”
3. Hearing , non-hearing ear “Sparing the otic capsule surgically
is preferred in patients with serviceable hearing “

o The classic procedures designed to access the posterior petrous

apex include:
1. Infralabyrinthine approach
2. Translabyrinthine approach “Sinodural”
3. Retrolabyrinthine approach
4. Subarcuate “provide drainage via cells that extend over the
superior semicircular canal and through the “hole in the
doughnut,” working through the center of the superior
semicircular canal”

o Procedures used to access the anterior petrous apex include:

1. Infracochlear approach.
2. Transotic approach “ FN not mobilized”
3. Transcochlear approach “ transposition of FN”
4. Middle fossa approach “ used when the disease involves the
anteriorpettous apex but spares the middle ear and mastoid”
5. Anterior approach through the glenoid fossa “described by
Ramadier and was popularized by Lempert. The exposure
involves removal of the anterior canal wall and condyle of the
mandible; exposure of the epitympanum; avulsion of the
tensor tympani; opening of the tensor semicanal; and then
dissection in the triangle between the carotid artery
(posterior), the cochlea (superior), and the middle fossa dura
(anterior). This approach can be modified by preserving the
anterior canal wall and condyle.))”
6. Endoscopic Trans-sphenoidal“the presence of venous sinuses
between the petrous apex and sphenoid, such as the
cavernous sinus, can make this approach challenging. It can
be considered for lesions located in the medial section of the
petrous apex abutting and/or prolapsing into the posterior
wall of the sphenoid sinus”

o In a non-hearing ear (Passing through Otic capsule):

o Translabyrinthine
o Transcochlear (transotic) approach
o Provides superior access for complete removal of mass lesions
o One disadvantage of these two approaches is that they could
potentially expose the cerebrospinal fluid (CSF) to the infectious
process.

1323
Riyadh et al. Notes

415

1324
Riyadh et al. Notes

416

1325
Riyadh et al. Notes

417
3. Facial Paralysis
9 It can occur as a complication of both acute and chronic otitis
media.
9 2nd most common extracranial complication from AOM facial palsy
9 Less commonly presents as a complication of COM
9 Facial paralysis can also be associated with
o Coalescent mastoiditis
o Masked mastoiditis
o Petrous apicitis.

™ Acute Otitis Media

9 Facial nerve is normally well protected in its bony canal.
9 Sometimes, the bony canal is dehiscent “Tympanic segment most
common”, and the nerve lies just under the middle ear mucosa.
9 It is in these cases that inflammation of middle ear spreads to epi-
and perineurium, causing facial paralysis.
9 Often presents in children with incomplete paresis
9 Comes on abruptly is usually short-lived with appropriate
treatment , good prognosis “rarely lasts longer than 3 weeks”
9 Facial nerve function fully recovers if acute otitis media is controlled
with systemic antibiotics.
9 Myringotomy or cortical mastoidectomy may sometimes be
required.

™ Chronic Otitis Media

9 Either results from cholesteatoma or from penetrating
granulation tissue.
9 Cholesteatoma destroys bony canal and then causes pressure on
the nerve, further aided by oedema of associated inflammatory
process.
9 Site of lesion depends on the anatomy of the cholesteatoma.
o Most commonly, the nerve is compressed in the tympanic
segment.
o Other sites of injury include :-
o Geniculate ganglion region (anterior epitympanic
cholesteatoma),
o Mastoid segment (facial recess/sinus tympani/ retrofacial
cholesteatoma)
9 Facial paralysis is insidious but slowly progressive , full paralysis,
worse prognosis
9 Treatment is urgent exploration of the middle ear and mastoid.
o Facial canal is inspected from the geniculate ganglion to the
stylomastoid foramen.
o Diamond burs should be used to carefully remove the bone of
the fallopian canal
o If granulation tissue or cholesteatoma has entered the bony
canal, uncapped in the area of involvement.
o Granulation tissue surrounding the nerve is removed
o If it actually invades the nerve sheath, it is left in place.

1326
Riyadh et al. Notes

o If a segment of the nerve 418

has been destroyed by the
granulation tissue, resection of nerve and grafting are better
left to a second stage when infection has been controlled and
fibrosis has matured.
o Significantly improved outcomes have been seen when surgical
decompression was performed within 1 week of the onset of
facial paresis
o Remember—a facial palsy occurring in the presence of chronic
ear disease is not Bell’s palsy and active treatment is needed if
the palsy is not to become permanent.
o Systemic steroid therapy is probably helpful to reduce
inflammation and edema in the acute phases of facial paralysis
for any type of OM

9 Four Indications for Mastoidectomy in Facial nerve Palsy

secondary to Otitis Media complication
1. History of COM
2. Onset of paralysis >2 weeks after onset of AOM
3. ENOG showing >90% Degeneration after 6 days ( poor
prognosis if left)
4. Failure of paralysis to resolve after appropriate Medical
management

1327
Riyadh et al. Notes

419
9 Diagnosis
9 Clinical by examination alone : AOM in very straightforward cases

9 CT scan:- very useful and will likely demonstrate the pathology and
site of lesion COM

9 MR imaging is helpful if lesions other than cholesteatoma are

considered

9 ENOG ( electroneuronography) , Electromyography (EMG) be

helpful in predicting prognosis for recovery in some cases ( see
facial palsy topic)

1328
Riyadh et al. Notes

420
5. Fistula of Labyrinth

9 There is thinning or erosion of bony capsule of labyrinth, usually of

the horizontal semicircular canal , rarely cochlea superior canal
and posterior canal ,vestibule
9
x Aetiology
9 The causes are:

A. Chronic suppurative otitis media with cholesteatoma “osteolysis

and uncovering of the labyrinth “ occurred in 7% of the
cholesteatomas in the large series by Gersdorff and colleagues “

oCan occur from resorption of the otic capsule due to

inflammatory mediators in the absence of cholesteatoma,
which typically occurs in COM with granulation.
B. Neoplasms of middle ear, e.g. carcinoma or glomus tumour.
C. Surgical or accidental trauma to labyrinth.

x Clinical features
9 Frequently asymptomatic and only discovered on CT imaging or at
surgery
9 Because part of membranous labyrinth is exposed and becomes
sensitive to pressure changes.
9 Patient complains of transient vertigo often induced by
o Pressure on tragus
o Cleaning the ear
o Valsalva manoeuvre
o Tullio phenomenon (vertigo secondary to auditory stimuli)
9 Vary degree sensorineural hearing loss is found in most of these
patients (68%)

1329
Riyadh et al. Notes

421
x Dx:-
9 The definitive diagnosis for a fistula is only made intraoperatively
9 CT may reveal bony erosion of the labyrinth 60 % of cases
9 Diagnosed by "fistula test" which can be performed in two ways.

x (a) Pressure on tragus

9 Sudden inward pressure is applied on the tragus, increases air

pressure in the ear canal and stimulates the labyrinth.
9 Patient will complain of vertigo.
9 Nystagmus may also be induced with quick component towards the
ear under test “ stimulated ear “

x (b) Siegle's speculum (pneumatoscopy)

9 When positive pressure is applied to ear canal

9 Patient complains of vertigo usually with nystagmus.
9 The quick component of nystagmus would be towards the affected
ear (ampullopetal displacement of cupula).
9 High false negative rate , this classic picture is not sensitive in the
preoperative identification pt of fisula
9 Periodic vertigo or significant disequilibrium is found in 62% to 64%
of patients who have fistulae preoperatively
9 The fistula test is positive in 32% to 50% of patients who are found
ultimately to have fistulae during surgical exploration.
9 Sensorineural hearing loss is found in most of these patients
(68%), it is not a sensitive indicator of fistula
9 Presence of “sensorineural hearing loss vertigo, or a positive
fistula test” in a patient who has a cholesteatoma should raise the
suspicion for a fistula
BUT
9 Absence of “sensorineural hearing loss vertigo, or a positive
fistula test” in a patient who has a cholesteatoma does not
guarantee an intact bony labyrinth.

1330
Riyadh et al. Notes

422
x CT
9 Preoperative CT imaging detection of an exposed labyrinth, facial
nerve, or dura, to aid in surgical planning
9 Detect fistulae accurately on preoperative CT has been reported as
60%
9 CT scans are no more sensitive than history and physical
9 examination in detecting labyrinthine fistulae

x The definitive diagnosis for a fistula is only made intraoperatively

“observed at surgery as a “blue line” parallel to the underlying
semicircular canal lumen

x Surgical approach is to assume the presence of a fistula in every

cholesteatoma case, to prevent unexpected complications.

1331
Riyadh et al. Notes

423

9 Staging system introduced by Dornhoffer and Milewski is the

classification used in the authors’ department, and is used in this
article to discuss fistulae and their management

9 Type I Fistula: Bony erosion and intact endosteum.

9 Type IIa Fistula: Endosteum is violated, but the perilymphatic
space is preserved.
9 Type IIb Fistula: Perilymph is violated by disease or inadvertently
suctioned.
9 Type III Fistula: Membranous labyrinth and endolymph have been
disrupted by disease or surgical intervention

1332
Riyadh et al. Notes

x Treatment 424
o In chronic suppurative otitis media or cholesteatoma:-
tympanomastoidectomy “ mastoid exploration” is often
required to eliminate the cause cholesteatoma
o Most appropriate management of the fistula remains an ongoing
debate.
o Most appropriate approach to the fistula is to perform a canal
wall down mastoidectomy, remove the bulk of the
cholesteatoma, and leave the fistula covered with the matrix
o Removal of the matrix increases the risk of sensorineural
hearing loss, and that by removing the sac itself
o Risk of significant sensorineural hearing loss as a result of
surgical manipulation highly controversial topic
o Pressure from the cholesteatoma is relieved and further bony
erosion or infectious complications are unlikely
o Graft site (fascia) OR shaped cap of bone secured with fibrin
glue if fistula is exposed

o Some investigators advocate the complete removal of the

cholesteatoma over the fistula, with repair of the bony defect in
all circumstances
o The size, extent, and location of the fistula should be considered
when determining whether complete cholesteatoma removal
should be attempted
o Contraindication of removal of cholestatoma matrix : Fistu-La
ƒ F: Firmly adherent
ƒ I: Infection
ƒ S: Size > 2 mm “ if smaller can remove safely “
ƒ T : Tympanoium (promontory/cochlea) high risk of SNHL
ƒ U : Only hearing ear
ƒ LAAAA

o No hearing loss resulted from the removal of type I , IIa fistulae

o 50% significant hearing loss postoperatively from the removal
type IIb and type III fistulae
o Systemic antibiotic therapy should be instituted before and after
operation to prevent spread of infection into the labyrinth.
o Intraoperative steroids experienced stable or improved hearing
90% of the time

1333
Riyadh et al. Notes

425
5. Labyrinthitis
9 There are 2 types of labyrinthitis:

x (a) Diffuse serous “toxic” labyrinthitis

x (b) Diffuse suppurative labyrinthitis

™ Diffuse Serous Labyrinthitis

9 It is diffuse intralabyrinthine inflammation without pus formation
and is a reversible condition if treated early.
9 Due to alteration of the inner ear tissue fluid environment due to
bacterial toxins enter the inner ear via the round or oval window, or
via a labyrinthine fistula.

x Aetiology
A. Most often it arises from pre-existing Fistula of Labyrinth
“circumscribed labyrinthitis “ associated with chronic middle ear
suppuration or cholesteatoma.
B. In acute infections of middle ear, cleft inflammation spreads
through annular ligament or the round window.
C. It can follow stapedectomy or fenestration operation.
D. Congenital labyrinthine deformities, such as Mondini deformity
and enlarged vestibular aqueducts

x Clinical features
o Mild cases complain of vertigo and nauseas
o Severe cases, vertigo is worse with marked nausea, vomiting
and even spontaneous nystagmus.
o Quick component of nystagmus is towards the affected ear. “
stimulate “
o As the inflammation is diffuse, cochlea is also affected with some
degree of sensorineural hearing loss.
o Serous labyrinthitis, if not checked, may pass onto suppurative
labyrinthitis with total loss of vestibular and cochlear function.
o Endolymphatic hydrops can be seen pathologically associated with
serous labyrinthitis.

1334
Riyadh et al. Notes

x Treatment 426
Medical Surgical
a. Bed rest, his head o To treat the source of
immobilised with affected infection.
ear above. o Cortical mastoidectomy (in
b. Antibacterial therapy is acute mastoiditis)
given in full doses to o Modified radical
control infection. mastoidectomy (in chronic
c. Steroid middle ear infection or
d. Labyrinthine sedatives, e.g. cholesteatoma)
prochlorperazine (Stemetil) o Medical treatment should
or dimenhydrinate always precede surgical
(Dramamine), are given for intervention
symptomatic relief of
vertigo ,nausia.
e. Myringotomy is done if
labyrinthitis has followed
acute otitis media and the
drum is bulging. Pus is
cultured for specific
antibacterial therapy

1335
Riyadh et al. Notes

427
™ Diffuse Suppurative Labyrinthitis
9 This is diffuse bacterial pyogenic infection invasion the labyrinth
with.
9 Results in rapid destruction of inner ear contents, with permanent
loss of vestibular and cochlear functions
x Aetiology
9 It usually follows serous labyrinthitis, pyogenic organisms entering
through a pathological or surgical fistula.

x Clinical features
9 There is severe vertigo with nausea and vomiting due to acute
vestibular failure. Spontaneous nystagmus will be observed with its
quick component towards the healthy side. “ paralytic”
9 Patient is markedly toxic.
9 There is total loss of hearing (permanent)
9 Relief from vertigo is seen after 3-6 weeks due to adaptation.
9 Suppurative process within the labyrinth can gain access to the
subarachnoid space via the fundus of the cochlea or the cochlear
aqueduct.
9 Otogenic sources are thought to be a common etiology of bacterial
meningitis in childhood.
9 Conversely, suppurative meningitis may extend into the labyrinth
and result in a secondary suppurative (meningogenic) labyrinthitis.
9 This phenomenon underlies the frequent association between
meningitis and hearing loss.
9 Ossification of the labyrinth (labyrinthitis ossificans) is frequently
seen following suppurative labyrinthitis, particularly due to S.
pneumoniae, and can complicate cochlear implantation
9 Early evaluation of hearing following meningitis and early cochlear
implantation when appropriate can result in substantially better
outcomes for patients with postmeningitic deafness.

x Treatment
9 It is same as for serous labyrinthitis.
9 Rarely, drainage of the labyrinth is required, if intralabyrinthine
suppuration is acting as a source of intracranial complications, e.g.
meningitis or brain abscess

1336
Riyadh et al. Notes

428

B. INTRACRANIAL COMPLICATIONS OF OTITIS MEDIA

1. Extradural Abscess or granulation tissue

2. Subdural Abscess
3. Meningitis
4. Brain Abscess
5. Lateral“ sigmoid” Sinus Thrombophlebitis (Syn. Sigmoid
Sinus Thrombosis) (Occluding ,Non occluding)
6. Otitic Hydrocephalus

1337
Riyadh et al. Notes

429

™ Routes of Spread into the Intracranium:

1. Direct extension from bone erosion

2. Lymphatic or hematogenous spread
3. Invasion through normal anatomic structures (labyrinth)
4. Spread through iatrogenic or traumatic defects
5. Extension through Hyrtle’s Fissure (embryologic remnant that
connects hypotympanum to the subarachnoid space , The cleft
extends between the bony labyrinth and the jugular bulb. ,
associate with CSF otorrhea)

1338
Riyadh et al. Notes

1. Extradural Abscess (Epidural 430Abcess) Or Granulation Tissue

9 It is collection of pus between the bone and dura.
9 It may occur both in acute and chronic infections of middle ear.

™ Pathology
9 In acute otitis media, bone over the dura is destroyed by
hyperaemic decalcification,
9 In chronic otitis media it is destroyed by cholesteatoma OR
coalescent mastoiditis
9 Direct extension via bone erosion pus comes to lie directly in
contact with dura. ( most common)
9 Also occur by venous thrombophlebitis (in this case, bone over the
dura remains intact.)
9 Extradural abscess may lie in :-
o Dura of middle or posterior cranial fossa
o Dura of lateral venous sinus (perisinus abscess).
9 The affected dura may be covered with granulations or appear
unhealthy and discoloured. (pachymeningitis).
9 Frequently associated with lateral sinus thrombophlebitis,
meningitis,and cerebritis or brain abscess.

™ Clinical Features
9 Most of the time are asymptomatic and silent, “not differ from
those found in COM” and are discovered accidently during
cholesteatoma surgery or CT scan for other purposes
9 No sensitive or specific symptoms suggestive of this disease
process.
9 However, Extradural Abscess is suspected when there is:

x (i) Persistent headache on the side of otitis media.

x (ii) Severe pain in the ear.
x (iii) General malaise with low-grade fever.
x (iv) Pulsatile purulent ear discharge.
x (v) Disappearance of headache with free flow of pus from the ear
(spontaneous abscess drainage).

1339
Riyadh et al. Notes

™ Diagnosis is made on 431

9 Contrast-enhanced CT :-
o May reveal erosion of the sigmoid plate or tegmen
o Rim enhancing lentiform epidural fluid collection

9 MRI
o Superior to CT in demonstrating small intracranial suppurative
lesions.
o Hyperintense relative to CSF on T1
o Isointense to CSF on T2

™ Treatment
(a) Mastoidectomy
9 Required to deal with the causative disease process.
9 Extradural abscess and granulation tissue is evacuated by removing
overlying bone till the limits of healthy dura without granulation
tissue is evident on all margins of the abscess are reached.
9 Cases where bony plate of tegmen tympani or sigimoid sinus plate
is intact but there is suspicion of an abscess, the intact bony plate
is removed to evacuate any collection of pus.
(b) Antibiotic
9 High dose for a minimum of 5 days
9 Closely observed for any further complications, such as sinus
thrombosis, meningitis or brain abscess.
9 Postoperative antibiotics are continued at least until the symptoms
of the abscess and otitis have resolved

1340
Riyadh et al. Notes

2. Subdural
432Abscess
9 This is collection of pus between dura and pia-arachnoid
membranes
9 Subdural abscess more commonly occurs in the frontal region from
sinusitis, but may result from ear disease
9 Subdural empyema rarely occurs due to COM
9 More typical complication of meningitis in infants (H. influenza ,
bilateral )
™ Pathology
9 Infection spreads from the ear by direct extension via erosion of
bone and dura or by thrombophlebitic process in which case
intervening bone remains intact.
9 Pus rapidly spreads in subdural space and comes to lie against the
convex surface of cerebral hemisphere causing pressure
symptoms.
9 With time, the pus may get loculated at various places in subdural
space.

™ Clinical Features
9 Signs and symptoms of subdural abscess are due to
a. Meningeal irritation
b. Thrombophlebitis of cortical veins of cerebru
c. Raised intracranial tension.
9 (a) Meningeal irritation
o Headache “earlies and most persistent symptom”, fever , malaise,
increasing drowsiness, neck rigidity and positive Kernig's sign.
9 (b) Cortical venous thrombophlebitis
o Veins over the cerebral hemisphere undergo thrombophlebitis
leading to aphasia, hemiplegia, hemianopia , coma.
o Jacksonian seizures( partial seizure) OR status epilepticus.(from
cortical damage)

9 (c) Raised intracranial tension

o papilloedema, ptosis and dilated pupil (IIIrd nerve involvement),
and involvement of other cranial nerves.

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Riyadh et al. Notes

433

™ CT scan or MRI are required for diagnosis (reveals crescent

shaped enhancement that does not cross midline)

™ Treatment
9 It is a neurological emergency :- series of burr holes or a
craniotomy is done to drain subdural empyema “neurosurgical
emergency”
9 IV antibiotics are administered to control infection.
9 Once infection is under control ( stable) , attention is paid to
causative ear disease which may require mastoidectomy.
9 Lumbar puncture should not be done as it can cause herniation of
the cerebellar tonsils.
9 The prognosis is poor.

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434
3. Meningitis
9 It is inflammation of leptomeninges " thin meninges" (pia and
arachnoid)
9 Usually with bacterial invasion of CSF in subarachnoid space.
9 It is the most common intracranial complication of otitis media
(especially in children < 5 years old)
9 It can occur in both acute (infants and children) and chronic otitis
media (adults)
9 AOM is the most common secondary cause of meningitis
9 10–20% risk of postmeningitic partial or total, unilateral or bilateral
SNHL
9 May cause ossification of the labyrinth or cochlea
9 All patients with meningeal signs should undergo otoscopic
examination to rule out AOM and CSOM

™ Mode of infection
9 In infants and children Blood-borne infection is common;
9 In adults, it follows chronic ear disease, which spreads directe by
bone erosion or retrograde thrombophlebitis or channels (Hyrtl’s
fissures);
9 In one-third of the patients with meningitis, another intracranial
complication may coexist.
9 The rapid onset of meningitis with AOM in a child with sensorineural
hearing loss may indicate the presence of an inner ear
malformation that allows communication through the oval or round
windows to the vestibule, cochlea. and internal auditory canal,
traumatic stapes dislocation or perilymphatic fistula
9 Increased risk with Mondini’s aplasia (from dilated vestibular
aqueduct)
9 Pathogens:
o S. pneumoniae ( most common)
o H. influenzae (non-typable),
o Nisseria meningitides

™ Clinical Features
9 Symptoms and signs of meningitis are due to
1. Presence of infection
2. Raised intracranial tension
3. Meningeal and cerebral irritation.

x (i) Fever often with chills and rigors.

x (ii) Headache.
x (iii) Neck rigidity.
x (iv) Photophobia and mental irritability , lethargy
x (v) Nausea and vomiting (sometimes projectile).
x (vi) Drowsiness which may progress to delirium or coma.
x (vii) new onset seizures
x (viii) Cranial nerve palsies and hemiplegia.

1343
Riyadh et al. Notes

435
9 Examination will show:
o (i) Neck rigidity
o (ii) Positive Kernig's sign (extension of leg with thigh flexed on
abdomen causing back pain)
o (iii) Positive Brudzinski's sign (flexion of neck causes flexion of
hip and knee)
o (iv) Tendon reflexes are exaggerated initially but later become
sluggish or absent,
o (v) Papilloedema (usually seen in late stages).

™ Diagnosis
9 CT or MRI with contrast will help to make the diagnosis.
9 It may also reveal another associated intracranial lesion.
9 show characteristic meningeal enhancement and rule out additional
intracranial complications
9 Lumbar puncture and CSF examination confirm the diagnosis (CSF
is turbid, cell count is raised and may even reach 1000/ml with
predominance of polymorphs; protein level is raised, sugar is
reduced and chlorides are diminished.)
9 CSF is always cultured to find the causative organisms and their
antibiotic sensitivity.

1344
Riyadh et al. Notes

436
™ Treatment
9 Medical
o Antimicrobial therapy:- third-generation cephalosporins and
vancomycin, should be administered while diagnostic tests are
ordered and arranged “gram-negative and anaerobe coverage”
o Culture and sensitivity of CSF will further aid in the choice of
antibiotics.
o Corticosteroids combined with antibiotic therapy significantly reduce
the rates of death , neurological & audiological “SNHL”
complications., should start early

9 Surgical
9 Meningitis following acute otitis media may require myringotomy or
cortical mastoidectomy.
9 Indications for mastoidectomy in otogenic Meningitis include:
o Presence of cholesteatoma
o Coalescent mastoiditis
o Bony erosion with direct extension of disease
o Persistence of symptoms despite maximal medical therapy
9 Surgery is undertaken as soon as general condition of patient
permits.
9 It may be done urgently, if there has been no satisfactory response
to medical treatment.

1345
Riyadh et al. Notes

4. Otogenic437Brain Abscess
9 50% of brain abscesses in adults and 25% in children are otogenic
in origin.
9 In adults, usually follows chronic suppurative otitis media with
cholesteatoma,
9 In children, usually follows acute otitis media “rare”
9 Most common sites are the temporal lobe or cerebellum
9 Cerebral abscess is seen twice as frequently as cerebellar abscess.

™ Route of Infection
9 Direct extension of middle ear infection through the tegmen (
cerebral) , Trautmann's triangle (Cerebellar)
9 Retrograde thrombophlebitis, in which case the tegmen will be
intact.
9 Often it is associated with extradural abscess, sigmoid sinus
thrombophlebitis or labyrinthitis.

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Riyadh et al. Notes

438

™ Bacteriology
9 Both aerobic and anaerobic organisms are seen.
9 Aerobic include
o Streptococci pyogenic
o Strep. pneumoniae,
o Staphylococcus sp
o Proteus sp

9 Anaerobic “rarely seen”

o Peptostreptococcus
o Bacteroides fragilis.
o H. influenzae

™ Pathology (Brain abscess develops through four stages):

9 (a) Stage of invasion (initial encephalitis)
o It often passes unnoticed as symptoms are slight.
o Patient may have headache, low-grade fever, malaise and
drowsiness.
9 (b) Stage of localisation (latent abscess)
o There are no symptoms during this stage.
o Localize the pus by formation of a capsule.
o The stage may last for several weeks.
9 (c) Stage of enlargement (manifest abscess)
o Abscess begins to enlarge.
o A zone of oedema appears round the abscess and is responsible for
aggravation of symptoms.
o seizures, LOC seen
o Clinical features at this stage are due to:
1. Raised intracranial tension.
2. Disturbance of function in the cerebrum or cerebellum, causing
focal symptoms and signs.
9 (d) Stage of termination (rupture of abscess)
o An expanding abscess in the white matter of brain ruptures into the
ventricle or subarachnoid space resulting in fatal meningitis.

1347
Riyadh et al. Notes

439
™ Clinical Features
9 Brain abscess is often associated with other complications, such as
extradural abscess, perisinus abscess, meningitis, sinus thrombosis
and labyrinthitis, and thus the clinical picture may be overlapping.

9 Clinical features can be divided into:

o (i) Those due to raised intracranial tension,
o (ii) Those due to area of brain affected. They are the localizing
features.

9 (a) Symptoms and signs of raised intracranial tension

x (i) Headache. severe and generalised, worse in the morning.
x (ii) Nausea and vomiting. usually projectile.
x (iii) Level of consciousness. Lethargy, which progresses to
drowsiness, confusion, stupor and finally coma.
x (iv) Papilloedema is absent in early cases. Appears late when
raised intracranial tension has persisted for 2-3 weeks.
x (v) Slow pulse and subnormal temperature.

9 (b) Localizing features

Localizing features
Temporal lobe abscess Cerebellar abscess

x (i) Nominal aphasia. If x (i) Headache & Neck

abscess involves dominant stiffness
hemispher, patient fails to x (ii) Spontaneous nystagmus
tell the names of common is common and slow
objects such as key, pen, irregular and generally to
etc. but can demonstrate the side of lesion.
their use. x (iii) Ipsilateral hypotonia
x (ii) Contralateral upper and weakness.
quadrantic Homonymous x (iv) Ipsilateral ataxia.
hemianopia. This is due to Patient staggers to the side
pressure on the optic of lesion.
radiations. x (v) Past-pointing and
x (iii) Contralateral motor intention tremor can be
paralysis. elicited by finger nose test.
x (iv) Epileptic fits. x (vi) Dysdiadokokinesia.
Rapid pronation and
x (v) Pupillary changes and supination of the forearm
oculomotor palsy. It shows slow and irregular
indicates transtentorial movements on the affected
herniation. side.
x (vii) Vertigo

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Riyadh et al. Notes

440
™ Diagnosis
9 Any patient with chronic ear disease who develops pain or
headache should be suspected of having intracranial extension.
9 Any patient who has otogenic meningitis, labyrinthitis or lateral
sinus thrombosis may also have a brain abscess.
9 Confirmation and localization of the abscess will require further
investigation.

1. CT
x Helps to find the site and size of an abscess., bony erosion of
the mastoid
x It also reveals associated complications such as:
o Extradural abscess
o Sigmoid sinus thrombosis
o Associated ear disease.

2. MRI shows soft-tissue lesions with more detail than CT but gives
no bone detail.

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Riyadh et al. Notes

441
9 Lumbar puncture
x CSF will show
o Some rise in pressure
o Increase in protein
o Normal glucose level.
o WBC of raised but is much less than seen in cases of meningitis.

9 CT findings in Temporal Bone Infection Contraindicating

Lumbar Puncture
o Lateral Shift of midline structures
o 4th Ventricle Obstruction
o Loss of Cisterns (Basal, Suprachiasmal, Superior Cerebellar,
or Quadrigeminal Plate Cisterns)

Treatment
Medical Neurosurgical Otologic
o High doses IV o The choice of o Associated ear
antibiotics gram surgical procedure disease which
positives, gram is left to the caused the brain
negatives, and judgement of the abscess needs
anaerobe neurosurgeon. attention.
o Options include:
o Raised intracranial i. Aspiration o AOM :myringotomy
tension can be through a burr with evacuation of
lowered by hole the purulent
dexamethasone, 4 ii. Excision of effusion is
mg i.v. 6 hourly or abscess, sufficient
mannitol 20% in iii. Open incision of
doses of 0.5 g/kg the abscess and o COM would require
body weight. evacuation of mastoidectomy to
pus. remove the
o Discharge from the irreversible disease
ear should be and to exteriorise
treated by suction the infected area
clearance and use
of topical ear o Surgery of the ear
drops. is undertaken only
after the abscess
has been controlled
by antibiotics and
neurosurgical
treatment.

™ PROGNOSIS
9 The prognosis of brain abscess has improved with the use of
antibiotics and
modern diagnostic methods but still carries a high mortality rate
may be 70%.
9 Left untreated, death from brain abscess occurs from pressure
coning, rupture into a ventricle or spreading encephalitis.

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Riyadh et al. Notes

442
5. Lateral Sinus Thrombophlebitis (Sigmoid Sinus Thrombosis)
9 It is an inflammation of inner wall of lateral venous sinus (sigmoid
and/or transverse sinus) with formation of a thrombus.
9 17% to 19% of intracranial complications

™ Aetiology
9 It occurs as a complication of:
o Chronic suppuration of middle ear and cholesteatoma
o Acute coalescent mastoiditis
o Granulation tissue
o AOM “common factor in children”

1351
Riyadh et al. Notes

™ Pathology 443
Pathological process can be divided into the following stages:
(a) Formation of perisinus o Abscess or granulation
abscess Or granulation forms in relation to outer
dural wall of the sinus.
o Overlying bony dural plate
may have been destroyed
by coalescent bone erosion
or cholesteatoma.
o Sometimes, it remains intact
when route of infection was
by thrombophlebitic of
mastoid emissary veins
(b) Endophlebitis and mural Inflammation spreads to inner
thrombus formation wall of the venous sinus with
deposition of fibrin, platelets,
and blood cells leading to
thrombus formation within the
lumen of sinus.
(c) Obliteration of sinus lumen o Mural thrombus enlarges to
and intrasinus abscess occlude the sinus lumen
completely.
o Organisms may invade the
thrombus causing intrasinus
abscess which may release
infected emboli into the
blood stream causing
septicaemia.
o Thrombus breaks down due
to intrasinus abscess,spread
& begins to seed to:
9 Superior sagittal sinus
(d) Extension of thrombus 9 Cavernous sinus
9 Mastoid emissary vein
9 Jugular bulb or jugular vein
“risk of septic pulmonary
emboli”

1352
Riyadh et al. Notes

444

™ Bacteriology
o Beta-hemolytic Streptococcus
o S. pneumoniae
o Pseudomonas
o Staphylococcus (including MRSA)
o H. influenza
o Klebsiella, Enterococcus, Proreus
o Anaerobes

™ Clinical Features
9 More recent articles have pointed out that this classic pattern
clinical features is not seen as frequently, current antibiotic therapy

1. Swinging pyrexia— Up to 40°C. “picket fence” (due to septicaemia)

“single high-fever reading should alert the clinician to the possibility
of sigmoid sinus thrombophlebitis “
2. Rigors.
3. Polymorph leucocytosis.
4. Positive Tobey–Ayer test (Quesckenstedt’s test):
o Compression of contralateral internal jugular vein rise in CSF
pressure.
o Compression of ipsilateral internal jugular vein no rise
(secondary to obstruction).
5. Griesinger’s sign (Pain over mastoid from occlusion of the mastoid
emmisary vein)
6. Neck pain and tenderness along the anterior border of the
sternocleidomastoid muscle
7. Meningeal signs— Sometimes.
8. Positive blood cultures, especially if taken during a rigor.
9. Papilloedema—Sometimes.
10.Metastatic abscesses—Prognosis poor.
11.Cortical signs—Facial weakness, hemiparesis.

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Riyadh et al. Notes

445
™ Dx :-
9 Typically determined with imaging study:
o CT with contrast may reveal enhancement within the sinus ,
characteristic Empty Delta sign ”enhancement of the triangular
sinus wall around non-enhandng intraluminal thrombus
produces”
o MRI more sensitive, reveals increased signal intensity in both T1
and T2 weighted images
o MRV/MRA may reveal total/partial occlusion, can be used
serially to evaluate for clot propagation or resolution.

™ Complications
x 1. Septicaemia and pyaemic abscesses in lung, bone, joints or
subcutaneous tissue.
x 2. Meningitis and subdural abscess.
x 3. Cerebellar abscess.
x 4. Thrombosis of jugular bulb and jugular vein with involvement of
IXth, Xth and XIth cranial nerves.
x 5. Cavernous sinus thrombosis. There would be chemosis,
proptosis, fixation of eyeball and papilloedema.
x 6. Otitic hydrocephalus, when thrombus extends to sagittal sinus
via confluens of sinuses decreased venous drainage from.
intracranial hypertension ,sudden worsening of a severe headache ,
high mortality rate

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Riyadh et al. Notes

446
™ Management :-
1. Surgery
9 Presence of COM with or without cholesteatoma treatment is a
Surgical
o Minimum mastoidectomy with removal of chronic infection,
granulation, and cholesteatoma is required.
o Sigmoid sinus is exposed and the surrounding epidural
abscess or granulation is removed.

9 The best way to manage the sinus itself is a point of controversy in

the otology literature. Most texts recommend a diagnostic needle
aspiration of the affected sinus, once it is exposed surgically.
o If the aspiration reveals normal blood return, then the sinus
is left intact;
o If the aspiration is negative or reveals frank pus, the sinus is
opened (Venotomy) and at least a portion of the infected clot
is evacuated.

9 Recent reports demonstrated that if the surrounding granulation

tissue and inflammation are removed through a mastoidectomy, the
sinus will recannalize without clot evacuation

9 Report demonstrated that with sinus thrombosis in the presence of

AOM, myringotomy and IV antibiotics resolved the infection, and
the sinus was shown to recannulate in three subjects without
mastoidectomy

9 Ligation of the internal jugular vein is not necessary unless

there is evidence of continued septic embolization after surgical
intervention and IV antibiotics. considered in the presence of septic
emboli.

9 Post op repeat MRI and MRV should be performed to rule out the
development of a secondary intracranial complication such as brain
abscess, or propagation of the thrombus into the superior sagittal
sinus.

2. Antibiotics

9 After surgical intervention, the patient should remain on IV

antibiotics for at least 2 weeks

3. Anticoagulants

9 When the thrombus is isolated to the sigmoid sinus , not been

shown to improve recanalization
9 Not necessary unless the clot is shown to involve the sagittal
sinus transverse sinus or cavernous sinus, or signs of
increased intracranial pressure persist despite medical
management.

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447

6. Otitic Hydrocephalus
9 Increased ICP secondary to Acute or Chronic Middle Ear disease
9 With or without Lateral/Sigmoid Sinus Thrombosis
9 WITHOUT evidence of Meningitis or Abscess “normal CSF
findings”

™ Mechanism
9 Pathophysiology is not understood completely
9 Lateral sinus thrombosis accompanying middle ear infection
causes obstruction to venous return.
9 If thrombosis extends to superior sagittal sinus, it will also
impede the function of arachnoid villi to absorb CSF.
9 Both these factors result in raised intracranial tension.
9 Multiple cases have been described in the absence of otitis or
otologic surgery
™ Clinical Features
9 Symptoms
x (a) Severe headache, may be accompanied by nausea and
vomiting.
x (b) Diplopia due to paralysis of VIth cranial nerve.
x (c) Blurring of vision due to papilloedema or optic atrophy.

9 Signs
x (a) Papilloedema
x (b) Nystagmus due to raised intracranial tension.
x (c) Lumbar puncture. CSF pressure exceeds 300 mm of water
(normal 70-120 mm H2O). It is otherwise normal in cell, protein
and sugar content and is bacteriologically sterile.

™ Diagnosis of otitic hydrocephalus is one of exclusion

™ Treatment
9 The aim is to reduce CSF pressure to prevent optic atrophy and
blindness.
This is achieved medically :-
o Initially Acetazolamide “Diamox “ (500 mg bid) &
corticosteroids
o Mannitol and Furosemide (0.5 g/Kg IV)
o Serial lumbar puncture or placement of a lumbar drain.
o Draining CSF into the peritoneal cavity VP shunt
9 Surgical :-
o Middle ear infection may require antibiotic therapy and
mastoid exploration to deal with sinus thrombosis
,Debride Granulations

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Otosclerosis (OS):

- Fibrous osteodystrophy of human otic capsule.

Primary disease of the bony labyrinth causing abnormal resorption and
deposition of bone in Endochondral layer.
- Incidence of 1% among Caucasian population.
- Age of onset between 20-40 years. Caucasians 8% to 12%, clinical
- Females are affected twice as males. disease 0.5% to 2%;
- Most common cause of progressive conductive hearing loss in adults.
- Definitive diagnosis can made only during exploratory tympanotomy.

- Otic Capsule:
o It is the bony labyrinth.
o Has three layers:
1. Endosteal layer:
x Innermost layer.
x Lines the bony labyrinth.
2. Endochondral layer:
x Develops from the cartilage and later ossifies into bone.
x It is in this layer that some islands of cartilage are left
unossified that later give rise to otosclerosis.
3. Periosteal layer:
x Outermost later.
x Covers the bony labyrinth.

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- Embryology
o Maturation of bony labyrinth plays a role in pathogenesis of OS.
o Otic capsule arises from mesenchyme surrounding the otic vesicle at 4
weeks of embryologic development.
o At 8 weeks, cartilaginous framework is initiated.
o At 16 weeks, endochondral osseous replacement of cartilaginous
framework begins in 14 centers.
o In some people, complete bony replacement does not occur and leaves
cartilage in certain locations.
o Fissula ante fenestram:
ƒ Located anterior to oval window (OW).
ƒ Last area of endochondral bone formation in the labyrinth.
ƒ Most common site of OS (80-90%).
o Other areas of otosclerotic lesions:
ƒ Border of round window (RW)
x 2nd most common site of OS (30%).
ƒ Apical medial wall of cochlea
ƒ Area posterior to cochlear aqueduct
ƒ Region adjacent to the semicircular canals
ƒ Stapes footplate

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- Histopathology:
o Three forms of otosclerotic lesions:
1. Otospongiosis (Early active phase):
x Early lesions appear adjacent to fissula ante fenestram as
sheets of connective tissue that replace bone.
x Osteocytes resorb bone around preexisting blood vessels,
which causes widening of the vascular channels and
dilation of microcirculation.
x Otoscopic exam can reveal the reddish hue caused by
these lesions (Schwartze sign).
x Formation of new spongy bone occurs which has enlarged
marrow spaces and rich with blood vessels and
connective tissue.
x Healthy surrounding bone has few viable osteocytes and
chondrocytes and is relatively avascular.
x With (H&E) staining, this new spongy bone appears
densely blue (The blue mantles of Manasse) which can
be found also in 20% of normal temporal bones.
2. Transitional phase
3. Otosclerosis (Late phase):
x Predominant finding is formation of sclerotic, dense bone
in areas of previous osseous resorption.
x The vascular spaces that were once dilated are narrowed
due to bony deposition.
x Although OS begins in endochondral bone, as the
spongiosis and sclerosis continue, the endosteal and
periosteal layers also become involved.
x Advanced lesions spread across stapedial annular
ligament and cause stapedial fixation.
x If the lesion progresses medially to involve endosteum of
the cochlea, SNHL results.
x It may spread in both directions, resulting in a mixed
sensorineural-conductive hearing loss.

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- Etiology of OS:
o Exact cause of otosclerosis is not known.
approximately 50% o The following facts have been documented in OS:
ƒ Heredity:
have positive family
x Autosomal dominant transmission with incomplete
history; 70% autosomal penetrance (25-40%).
dominant with 25% to x 30% of cases are sporadic.
40% penetrance x 50-60% of otosclerotics have positive family history.
ƒ Race:

White races ( high in Caucasians ) are affected more than Negros.
ƒ Sex:
x Females are affected twice as often as males.
ƒ Age of onset:
x Hearing loss starts between 20-40 years of age.
x Rare before 10 years.
x Juvenile OS may progress more rapidly.
ƒ Viral infection:
x Electron microscopic and immunohistochemical studies of
OS lesions have shown RNA related to measles virus.
x It is likely that otosclerosis is a viral disease as has been
suggested for Paget's disease.
ƒ Autoimmune:
x No evidence suggesting this etiology.

Hormonal
Hormonal factor may play a role; some females with OS appear to have
their condition worsen during pregnancy. Estrogen receptors have been
noted in the OS plaques. However, more recent data minimize the
association between pregnancy and worsening of OS

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- Types of Otosclerosis:
o Areas of otosclerosis involvement dictate the clinical presentation.

1. Stapedial OS:
ƒ Most common type of OS involves the stapes.
ƒ Cause fixation of the stapes footplate.
ƒ CHL is the presenting symptom.
ƒ Types:
x Anterior focus:
o Most common type.
o Located at Fissula ante fenestram
o Anterior to oval window.
x Posterior focus:
o Located at Fissula post fenestram
o Posterior to oval window.
x Circumferential:
o Located around the margin of the stapes footplate.
x Biscuit:
o Located in the footplate without involvement of
annular ligament.
o Minimal fixation may occur.
o Stapes footplate can become mobilized
inadvertently during stapes procedure, placing the
patient at higher risk of post-op SNHL.
x Obliterative:
o Completely obliterate the oval window niche.

2. Cochlear OS:
ƒ Involves region of round window or other areas in the otic
capsule.
ƒ Cause SNHL due to liberation of toxic materials into the inner
ear fluid or direct extension of lesions into the cochlea.
ƒ SNHL is usually associated with significant stapedial OS.
ƒ Isolated pure SNHL can be seen without associated CHL.
ƒ Rarely associated with vertigo.

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ƒ Shambaugh criteria to identify patients presenting with isolated
SNHL due to OS (Cochlear OS):
1. Schwartze sign in either ear.
2. Family history of OS.
3. Unilateral CHL consistent with OS and bilateral,
symmetric SNHL.
4. Audiogram with flat or cookie-bite curve with excellent
discrimination.
5. Progressive pure cochlear loss beginning at the usual age
of onset for OS.
6. CT showing demineralization of cochlea typical for OS
7. Stapedial reflex showing diphasic "on-off effect” seen
before stapedial fixation.

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454
- Clinical presentation:

o History:
ƒ Slowly progressive hearing loss over period of years.
ƒ 70% of cases presented with bilateral involvement.
ƒ More apparent to the patient at age 30-40 years.
ƒ More common in females (2:1).
ƒ Hearing improves in noisy situations (Paracusis of Willis)
because people speak louder in noisy surroundings.
ƒ Tinnitus present in 75% of cases.
ƒ Rarely associated with vestibular symptoms
x Mild but persistent.
x SSCCD and Meniere disease should be ruled out.
ƒ No history of infections or trauma.
ƒ Positive family history of hearing loss in 60% of cases.
ƒ Pregnancy associated with acceleration of otosclerosis.

o Physical Examination:
ƒ Oto-microscopic examination:
x Intact and mobile TM.

Schwartze sign “Flemingo's pink signs” :
o Red appearance seen through TM
due to hyperemia of the
promontory mucosa.
o Seen in 10% of active OS due to
increased vascularity.

ƒ Tuning fork:
x Shows picture of CHL.
x Weber will lateralizes to the ear with greater CHL.
x Rinne will be negative (BC > AC) in the affected ears.

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o Audiometry:
ƒ Pure tone audiometry:
x Shows mainly CHL with ABG begins in low frequencies.
x In absence of cochlear involvement, maximum CHL
produced by complete stapes fixation is 60-65dB.
x In cochlear otosclerosis, AC thresholds continue to worsen
and start to have MHL or SNHL, with high frequencies
becoming severely affected.

Carhart notch:show in audiograms. bone conduction (sensorineural hearing loss)
o Depression of BC occurs at different frequencies
but maximum at 2000 Hz.
ƒ 5 dB at 500 Hz
ƒ 10 dB at 1000 Hz
ƒ 20 dB at 2000 Hz
ƒ 5 dB at 4000 Hz
o It is a mechanical artifact secondary to stapes
fixation and the change in the normal ossicular
resonance, which is around 2000 Hz in human.
o Disappears after successful stapedectomy.
o Occurs in any condition which reduces the inertial
vibration of the stapes footplate
(tympanoseclerosis, ossicular fixation)

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456
ƒ Speech audiometry:
x Word recognition scores are usually excellent in patients
with OS even in the later stages of the disease process.
x Discrimination will be affected with cochlear involvement.

ƒ Tympanometry:
x Type A in 95% of patients with OS.
x 5% will show curve of ossicular stiffness. (Type As).
x Multi-frequency tympanometry:
o Based on the analysis of tympanograms at a wide
range of frequencies between 226 and 2,000 Hz.
o Changes in the transmission characteristics of
middle ear system can be easily determined from
the changes in the resonant frequency.
o Otosclerosis increase the stiffness of middle ear
system due to the fixation of the stapes and
therefore increases resonant frequency.

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Riyadh et al. Notes
457
ƒ Stapedial reflex:
x Very sensitive indicator of otosclerosis.
x Earliest evidence of OS is Diphasic pattern/on-off effect:
o Brief increases in compliance occur at onset and
end of the stimulus when the probe is in the
affected ear.
o Occurs as a result of the movement of posterior
portion of footplate to move independent of the
fixed anterior portion of the footplate due to
elasticity of footplate.
o Pathognomonic of early stapedial fixation.
o Seen prior to development of a detectable ABG in
PTA.
x As the disease progresses, stapes gets fixed and both
ipsilateral and contrlateral stapedial reflexes become
absent acoustic reflex
x Presence of stapedial reflexes with significant CHL
warrants evaluation for SSCD.

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o Vestibular Tests:
ƒ Indicated in patients with vestibular symptoms to rule out
SSCCD and Meniere disease.
ƒ Vestibular Evoked Myogenic Potential (VEMP):
x cVEMP have become a standard test in the workup of a
patient with SSSCD or Meniere's disease.
o Patients with SSSCD will have decreased thresholds
(increased sensitivity) to sounds.
o Patients with Meniere's disease will have increase
threshold or absent response to sounds.

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459
o Imaging Studies:
ƒ HRCT CT temporal bone:
x Indicated in all patients with OS.
x Objectives:
o Confirm the diagnosis.
o Rule out other differential diagnosis.
o Pre-op planning.
x Stapedial OS:
o Hypodense demineralised plaque can be seen in
the region of fissula ante fenestram.
x Cochlear OS:
o Per-cochlear hypodense “double ring” sign
represents demineralized foci in the otic capsule.
o Basal turn ossification in severe cases.
x Normal CT does not rule out otosclerosis.

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Riyadh et al. Notes
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ƒ MRI:
x Indicated in patients with cochlear OS planned for CI to
evaluate the patency of cochlea.
x Cochlear OS:
o Ring of peri-cochlear and peri-labyrinthine
intermediate signal on T1.
o Mild-moderate enhancement in T1 post contrast.
o Obliteration of fluid space in basal turn of cochlea
in severe cases.

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- Differential diagnosis of OS:

o Tympanosclerosis:
ƒ Mimic OS but with history of recurrent AOM or VT insertion,
ƒ TM is thickened with associated myringosclerosis.

o Incus/malleus fixation:
ƒ Lateral ossicular chain fixation, malleus and/or incus become
fixed in epitympanum (at superior malleolar ligament).
ƒ Results in immobility of all the ossicles.
ƒ Occurs congenitally or may be acquired through
tympanosclerosis.
ƒ Entire ossicular chain must be examined with every exploratory
tympanotomy to avoid overlooking this lesion.
ƒ Almost always associated with type As tympanogram.

o Congenital footplate fixation:

ƒ Presents at earlier age juvenile OS.
ƒ Can be detected at age of 3 years, whereas juvenile OS was not
detectable until age of 10 years.
ƒ Less likely to have positive family history (10%) compared to
juvenile OS (50%).
ƒ Incidence of congenital malleus fixation is higher in children
with congenital footplate fixation (25%) than in children with
juvenile OS (3%).
ƒ 80% of juvenile OS patients had post-op closure of ABG to
within 10dB compared to 44% only in patients with congenital
footplate fixation.

o Ossicular discontinuity:
ƒ Flaccid TM on pneumatic otoscopy.
ƒ Type Ad tympanogram.
ƒ History of recurrent COM suggests incus necrosis.
x TM may be normal or thickened or atrophic.
x Fibrous union of incudostapedial joint can produce ABG
wider in high frequencies than in the lower frequencies.
ƒ History of temporal bone trauma:
x Fracture of stapes super-structure or incus long process
have a similar audiometric configuration as OS.
x Fibrous union forms with resultant resolution of CHL.
x Distorted TM surface landmarks occasionally provide
evidence of prior temporal bone trauma.

o OME and ME masses:

ƒ Audiometry and physical examination will help to make
thediagnosis apparent.

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o Superior Semicircular Canal Dehiscence:
ƒ Patients will present with low frequency CHL that is not due to
middle ear pathology.
ƒ Autophony and pulsatile tinnitus.
ƒ Vertigo induced by loud noises.
ƒ Normal stapedial reflex.
ƒ CT scan will show SSCD.

o Paget Disease (Osteitis Deformans):

ƒ Disease with diffuse bony involvement that is histologically
similar to OS.
ƒ In contrast to OS, Paget disease begins in the periosteal layer
and involves the endochondral bone last.
ƒ Temporal bone involvement can produce SNHL, but stapes
involvement or fixation rarely occurs.
ƒ Elevation of the serum alkaline phosphatase level and
involvement of other skeletal bones are often seen.

o Osteogenesis Imperfecta (Van der Hoeve syndrome):

ƒ Autosomal dominant defect of osteoblast activity.
ƒ Should be suspected in presence of:
x Blue sclera
x Progressive CHL
x Multiple fractures.
ƒ CHL is secondary to stapes fixation and these patients can have
stapes surgery with results similar to those with otosclerosis.

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464
Treatment of otosclerosis includes hearing aid, stapedectomy, and sodium fluoride
- Treatment of OS: therapy. Treatment of choice for a young stapedial otosclerosis office going patient is
stapedectomy. Sodium fluoride (NaF) is being used in the treatment of cochlear
otosclerosis.
o Observation:
ƒ Indications of observation:
x Unilateral OS.
x Mild CHL.
x Young age.
ƒ Follow-up for progression with audiograms every 6-12 months.
ƒ Patients with special needs should be encouraged to consider
surgery or amplification even if they have unilateral loss.

o Conventional Hearing Aids:

ƒ All patients with OS and CHL should be offered HA during
counseling.
ƒ Indications of HA:
x Patients not fit medically for surgery.
x Patients refusing surgery.
x Only hearing ear.
ƒ Patients with stapedial OS have excellent discrimination and HA
may provide effective treatment.
ƒ Patients with advanced OS and severe MHL can obtain
serviceable hearing with HA after stapedectomy.
ƒ HA avoids risk of SNHL that could occur from stapes surgery.
ƒ However, HA is not capable of providing a good satisfaction
compared to a successful stapes surgery.

o Medical Management:
ƒ Indications of Medical management:
x Cochlear otosclerosis.
x Vestibular symptoms
x Pre-op stabilization
ƒ Stabilize active OS to prevent progression of CHL, SNHL and
dizziness.
1. Sodium Fluoride:
x Fluoride ions replace hydroxyl ions forming a more stable
fluorapatite complex (instead of hydroxyapatite crystal)
that resists osteoclastic degradation.
x 60mg daily to obtain the maximum bone calcifying effect.
x Evaluation of efficacy is based on:
o Disappearance of Schwartze’s sign
o Stabilization or improvement in hearing
o Improvement in CT appearance of otic capsule.
x Contraindication:
o Chronic nephritis
o Rheumatoid arthritis
o Pregnancy, lactation and children
2. Vitamin D.
3. Calcium supplement.

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o Stapes Surgery:

ƒ Objectives of stapes surgery:

1. Open oval window for sound transmission to labyrinth.
2. Reconstruct the conductive bridge between incus and the
labyrinth.
3. No complications.

ƒ Indications of stapes surgery:

x Socially unacceptable CHL or MHL:
o >30 dB ABG
o Negative Rinne with 512 Hz tuning fork.
o Good speech discrimination (>60%).

ƒ Poor candidates of stapes surgery:

x Young patients:
o High risk of OW re-closure after successful initial
procedure.
o High risk of AOM and eustachian tube dysfunction.
x Biscuit and obliterative OS:
o 62% success rate with closure of ABG to 10 dB.
o Higher risk of SNHL from drilling (4%).
x Revision surgery:
o Lower success rate 65%.
o Higher risk of post-op SNHL (7%).
o HA is good alternative.

ƒ Important pre-op considerations:

x Unilateral OS:
o Optimal results can be obtained only if:
ƒ Hearing in the two ears becomes nearly
equal after surgery.
x Bilateral OS:
o Initial stapes surgery should be done for the poorer
hearing ear.
o Better ear can be operated after 6–12 months of
uncomplicated first ear surgery due to risk of
delayed post-op SNHL.
x Children:
o Children < 5 years with CHL >30db should be fitted
with HA and surgery postponed in unilateral cases
until the child is old enough to participate in the
decision process.
o Children > 5 years with CHL >30db and bilateral
congenital stapes fixation, and SRT >35 dB may be
considered surgical candidates if the child or
parents do not accept HA.

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466
ƒ Results of stapes surgery:
x Hearing:
o Post-op hearing results reveal closure of ABG
within 10dB of the pre-op BC level in 90% of
patients.
ƒ Immediate hearing improvement is noted in
some patients intra-op or in the recovery
area.
ƒ Other patients report gradual hearing
improvement with occasional associated
vestibular symptoms due to serous
labyrinthitis.
ƒ Balance disturbances usually resolve within
1-2 days up to few weeks.
ƒ Post-op audiogram done 2-3 months to allow
enough time for middle ear fluid and blood to
resorb.
o 10% of patients experience either worsening
hearing or no improvement
o 2% of patients suffer persistent SNHL.
o 1% of patients will have profound SNHL.
x Tinnitus:
o 85% of patients with tinnitus improved after stapes
surgery.

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ƒ Relative contraindications of stapes surgery:
1. Certain Occupations:
o Occupation requiring repeated exposure to
barometric pressure changes (Scuba divers):
ƒ Greater risk for post-op fistula and
prosthesis dislocation.
o Occupation requiring excellent balance:
ƒ Risk of post-op vertigo and dizziness.
o Occupation requiring taste function (Chefs):
ƒ Risk of post-op dysgeusia secondary to
stretching or cutting the chorda tympani
nerve.
2. TM perforation:
o Greater risk of post-op SNHL.
o TM should be fully repaired before attempted
stapes surgery (i.e., staging of the ear).
3. Active Meniere:
o Greater risk of post-op SNHL.
o When endolymphatic space is dilated
(endolymphatic hydrops), saccule may be enlarged
to and adheres to undersurface of stapes footplate
and stapes procedure can injure the saccule
resulting in profound SNHL.
o Patients should be free of symptoms for ≥6months
before undergoing stapes surgery.
4. Active OS:
o Positive Schwartze sign
o Pregnancy
o TM atelectasis
5. Severe Eustachian tube dysfunction
6. History of cholesteatoma
7. Active otitis externa.
8. Active otitis media.
9. OME.

ƒ Absolute contraindications of stapes surgery:

1. Only hearing ear.
2. Better hearing ear.

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Riyadh et al. Notes
468
ƒ Types of stapes surgery:
x Aims to perform a fenestration over the footplate into the
vestibule, which varies in size depends on the technique.
x With larger fenestrations, there is a larger conductive
advantage gained in hearing but the vestibule is more
prone to trauma which leads to severe post-op vertigo or
disequilibrium which usually resolves shortly.
x Either technique can be used in the hands of an
experienced surgeon to obtain satisfactory and stable
long-term hearing results.

x Total Stapedectomy:
o First stapes surgery described for OS.
o Steps:
ƒ Trans-canal approach.
ƒ Tympanomeatal flap is elevated from 6-12
o'clock, 6mm lateral to the annulus.
ƒ TM is elevated with the annulus.
ƒ Chorda tympani nerve is identified and
preserved.
ƒ Scutum (Medial most posterior-superior EAC
wall) is removed to visualize the OW,
pyramidal process, tympanic segment of
facial nerve.
ƒ IS joint is separated.
ƒ Lateral ossicular chain movement is assessed
to rule out lateral chain fixation.
ƒ Stapes superstructure and footplate are
palpated.
ƒ RW reflex is assessed.
ƒ Stapedial tendon is divided.
ƒ Placing control holes in footplate.
ƒ Anterior and posterior crus are fractured.
ƒ Stapes suprastructure is fractured and
extracted.
ƒ Entire footplate is removed and replaced
with graft (temporalis fascia, vein graft,
tragal perichondrium, gelfoam) and wire or
piston prosthesis.
o Advantages:
ƒ Better post-op hearing gain at lower
frequencies (250 and 500Hz) compared to
partial stapedectomy or stapedotomy.
o Disadvantages:
ƒ Higher risk of damage to the inner ear and
resultant vertigo or SNHL.

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470

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Riyadh et al. Notes
471
x Partial Stapedectomy:
o Modification of total stapedectomy.
o Considered for patients with isolated anterior
fixation at the fissula ante fenestram.
o Steps:
ƒ Similar initial steps of Total Stapedectomy.
ƒ IS joint is not separated.
ƒ Stapedial tendon is not divided.
ƒ Removal of only the anterior footplate and
anterior crus.
ƒ Connective tissue graft is placed aver the
exposed area.
o Advantages:
ƒ Better post-op hearing gain at higher
frequencies (4,000 Hz) compared to total
stapedectomy.
ƒ Benefit for patients working in noisy
environment due to preservation of stapedial
tendon.

x Stapedotomy:
o New trend in stapes surgery.
o Longstanding results of stapedotomy procedure
have been comparable to total stapedectomy.
o Steps:
ƒ Similar initial steps of Total Stapedectomy.
ƒ IS joint is separated.
ƒ Stapedial tendon is divided.
ƒ Anterior and posterior crus are fractured.
ƒ Stapes suprastructure is fractured and
extracted.
ƒ Small circular fenestra is created (with
skeeter or laser) in the center of footplate.
ƒ A prosthesis is inserted into stapedotomy
opening and attached to lenticular process of
incus.
ƒ Clotted blood or soft tissue graft can be used
to seal the oval window.
ƒ Incus is gently palpated to observe the
motion of the prosthesis.
o Advantages:
ƒ Better post-op hearing gain at higher
frequencies (4,000 Hz) compared to total
stapedectomy.
ƒ Lower risk of damage to the inner ear and
resultant vertigo or SNHL compared to total
or partial stapedectomy.

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Riyadh et al. Notes
473
x Stapes Mobilization:
o Performed only in selected group of patients in
whom a small point of fixation from OS can be seen
and where improved stapes mobility can be clearly
demonstrated.
o High risk of re-fixation.

ƒ Laser vs Microdrill during stapedotomy:

x The surgeon's operative experience and skill are
considered the most important factors in determining the
success and incidence of complications.
x No significant differences in post-op PTA results.
x No significant difference in post-op SNHL rates.
x Microdrill (Skeeter):
o More useful for thick footplate.
x Laser:
o May reduce the mechanical trauma to the stapes,
causing decreased labyrinthine irritation and
possibly better results.
o Most common types (Argon, KTP, CO2)

ƒ Types of stapes prostheses:

1. Wire teflon piston:
o Technically difficult and can results in delayed
failure.
o Wire loop must be manually crimped to incus.
o If crimped too tightly, incus necrosis may result
because of attenuation of the fragile blood supply.
o If crimped too loosely, vibration of the wire loop
may create a gradual erosion through the incus.
2. Heat-activated self-crimping prosthesis:
o Provides a reliable, consistent snug fit of the wire
loop on the incus.
o Once positioned on the incus, a laser, bipolar, or
heating filament can be used to self-crimp the
prosthesis.
3. Bucket-handle prosthesis

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474
ƒ Intra-op consideration and complications:

1. Bleeding:
o Intra-op bleeding can be troublesome during the
delicate parts of the stapedectomy.
o Most common cause of bleeding is mucosal trauma.
o Intra-op bleeding can significantly hamper surgery
during the hyperemic or active phase of OS.
o Some surgeons recommend pre-op sodium fluoride
in these patients to stabilize the lesion.

2. TM perforation (2%):
o May occur intra-op during elevation of TM from the
o sulcus in the posteroinferior area.
o Avoided by careful identification of annular
ligament.
o Perforation does not prevent completion of the
operation.
o Management:
ƒ Small perforations usually heal with
placement of a small piece of Gelfoam or
paper patch over the perforation
ƒ Larger tears may require an underlay
myringoplasty using tissue or sometimes
require deferring stapes surgery.
Persistent post-op perforations should be repaired
within 4-6 weeks after surgery to prevent any
problems with transcanal contamination of the
middle ear and a subsequent otitis media and
SNHL.

3. Lateral Ossicular Chain Fixation (1-10%):

o Lateral chain movement should be assessed after
separation of incudostapedial joint.
o Fixed malleus head is rare and usually associated
with stapes fixation.
o Management:
ƒ If no stapes fixation:
x Incus replacement prosthesis, or
x TORP with cartilage graft.
ƒ If there is stapes fixation:
x Removal of malleus head and incus
and the use of malleus to OW
prosthesis.

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4. Incus subluxation/dislocation or fracture of long
process of incus:
o Occurs during:
ƒ Curettage of scutum.
ƒ Separation of IS joint
ƒ Placement of prosthesis
o Management:
ƒ Placing the prosthesis on the remaining incus
(Notched bucket-handle prosthesis) with
excellent hearing results.
ƒ Staging the procedure and coming back at
later time may allow incus to heal and be
utilized in future.
ƒ For dislocated incus, remove the incus and
use malleus to OW prosthesis.
ƒ Malleus to OW prosthesis is more difficult to
place has poorer post-op hearing results.

5. Exposed overhanging facial nerve:

o Exposed facial nerve occurs in 9% of stapes
procedures.
o Usually, it does not present a problem intra-op
unless it blocks access to the footplate and makes
completion of the procedure impossible.
o Management:
ƒ Retracting the nerve gently superiorly with a
small suction catheter, while the drill or laser
is used to create the fenestra.
ƒ A prosthesis touching the facial nerve does
not create a problem for post-op hearing or
facial function.
ƒ If it the facial nerve is causing a significant
block to the access then the procedure
should be aborted.

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6. Persistent Stapedial Artery:

o Embryologic remnant of second branchial arch.
o Originate from internal carotid artery and pass in
obturator foramen between the crus of stapes
footplate.
o Can be predicted pre-op by CT that shows absent
foramen spinosum which contains middle
meningeal artery.
o Management:
ƒ The vessel must be divided or displaced to
gain access to the footplate with high risk of
bleeding.
ƒ Persistent stapedial artery can be difficult to
coagulate with bipolar cautery or laser and
surgery should be aborted.

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7. Floating footplate:
o Fixed footplate suddenly becomes mobile after
stapes superstructure is removed with risk of
depressing footplate into the vestibule.
o Rare with the use of laser or microdrill, especially
when the crura are left in place until after the
prosthesis is placed.
o Attempts to remove the depressed footplate ca
result in significant SNHL and vertigo.
o Management:
ƒ If control holes were made:
x Small right angle hooks or needles
placed through the control holes made
previously to lift the footplate out of
the vestibule.
ƒ If no control holes made:
x Drilling a small hole in the promontory
at the inferior edge of the footplate
then a small hook can be used to
elevate footplate gently out of the oval
window.
x Connective tissue graft and prosthesis
can be placed lateral to depressed
footplate after making the fenestra
with microdrill or laser with
unpredictable results.
ƒ May abort the procedure and wait for the
footplate to refix and re-operate later (laser
minimize floating footplate).

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8. Solid or obliterated footplate:
o When present one ear, obliterative OS is present in
contralateral ear in 50% of cases.
o Higher risk of SNHL from drilling (4%).
o Management:
ƒ Microdrill to create a fenestra.
o Partial or complete re-closure of oval window
following primary stapedectomy may occur which is
considered to be a cause of early failure (within
one year) and some authors advocate the use of
sodium fluoride post-op in these patients.

9. Perilymph gusher:
o Profuse perilymph gusher (CSF leak) immediately
on opening the vestibule.
o Perilymph volume is on the scale of microliters so
this abundant flow represents CSF.
o Rare with incidence of 0.03%.
o Associated with congenital footplate fixation in
pediatric patients.
o Causes:
ƒ Modiolar defect with communication to
fundus of IAM.
ƒ Patent cochlear aqueduct. or more
commonly a modiolar
o Total stapedectomy in presence of gusher increases
the risk of post-op SNHL.
o The control holes placed before footplate removal
allows for early identification of this problem.
o Management:
ƒ Elevation of head of the bed.
ƒ Small fenestra stapedotomy.
ƒ Placement of a tissue seal over footplate
defect.
ƒ Lumbar drain may be needed to decompress
the subarachnoid space to allow for
adherence of the graft to the defect in
footplate.

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ƒ Post-op care:
x Bed rest and head elevation 30 degrees:
o Reduce the perilymph pressure in the vestibule.
x If no vertigo or dizziness is present, the patient can be
discharged home after 2-4 hours of surgery if under LA.
x Instructions:
o Dry ear precautions until TM is healed.
o Avoid flying for 5 days after surgery.
o Avoid nose blowing, straining, diving and lifting
heavy objects for 4 weeks after surgery.
o Cough and sneeze with the mouth open.

ƒ Post-op complications:

1. SNHL:
o Most devastating surgical complication.
o SNHL may be mild or isolated to high frequencies.
o 2% of patients will have persistent SNHL.
o 1% of patients will have profound SNHL
o Surgical trauma is the most common cause of
permanent SNHL following stapes surgery.
o Laser is associated with a lower incidence of SNHL.
o Risk factors:
ƒ Extensive drilling (obliterative type).
ƒ Prior traumatic mobilization.
ƒ Bleeding (Blood is ototoxic).
ƒ Surgical instrument trauma.
o Management:
ƒ Prednisone is started immediately and
tapered over 10 days.
ƒ Course begins with 60 mg daily for 5 days
and on the sixth day, the dose is reduced to
40 mg for 1 day, followed by a 10-mg/day
reduction until the tenth day.

2. Serous labyrinthitis:
o Common after stapes surgery because of a certain
amount of inflammation within the inner ear.
o Patients may exhibit mild unsteadiness, positional
vertigo, or high-frequency SNHL.
o Irritative nystagmus (to operated ear) occur
usually with serous labyrinthitis.
o Paralytic nystagmus (to non-operated ear) occurs if
there is inner ear injury.
o Management:
ƒ Spontaneous recovery occurs within several
days to weeks.

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3. Acute otitis media:
o Rare post-op complication
o High risk of SNHL in the operated ear.
o The newly created OW partition allows a middle ear
infection to quickly involve the labyrinth
(suppurative labyrinthitis) and potentially
meningitis.
o Management:
ƒ Intensive systemic antibiotic therapy for
otitis media should initiated immediately to
avoid any significant sequelae.

4. Chorda tympani injury:

o Occurs in up to 30% of cases.
o Less severe symptoms are reported with complete
sectioning of the nerve than with stretching or
partial tearing.
o If the nerve has been stretched or otherwise
injured, it is preferable to section it.
o Symptoms include:
ƒ Dry mouth
ƒ Tongue soreness,
ƒ Metallic taste
o Management:
ƒ Spontaneous recovery occurs within 3-4
months.

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5. Partial of total facial weakness:
o Facial nerve paralysis occurs less than 0.5%
o Caused by:
ƒ Delayed bell’s palsy from re-activation of
herpes virus without injury to facial nerve
(after 5 days post-op).
ƒ Injury or stretching to dehiscent facial nerve
(immediate post-op).
ƒ Local anesthetic effect (immediate post-op).
o Management:
ƒ Usually partial weakness and complete
recovery occurs within 6 weeks with
prednisone treatment in case of delayed
bell’s palsy.

6. Reparative granuloma:
o Granulation tissue around OW.
o Rarely seen today (0.1%).
o Risk factors for reparative granuloma:
ƒ Total stapedectomy
ƒ Use of gelfoam or fat as OW sealant
ƒ Presence of powder on operating gloves.
o Hallmark of post-op granulation is progressive or
sudden SNHL after earlier post-op hearing
improvement.
o Occurs within 1-6 weeks post-op.
o Suspected when the commonly seen symptoms of
serous labyrinthitis (SNHL and vertigo) persist
beyond several days after operation or worsen with
time.
o Examination shows a reddish discoloration in
posterosuperior quadrant of TM.
o CT scan can helpful in the diagnosis and to assess
status of the prosthesis/vestibule.
o The overall outcome of this potentially devastating
process is related to early diagnosis and treatment.
o Management:
ƒ Prompt recognition and removal of the
granuloma from around the oval window,
removal of OW seal and prosthesis with
replacement using a different material.

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7. Perilymph fistula:
o Rare with incidence of 3-10%.
o May occur in the early post-op period or many
years later.
o The most common cause of fistula in fistula
exploration surgery is total stapedectomy.
o Incidence is much less after stapedotomy with
small fenestra technique.
o Presenting symptoms is fluctuating or progressive
MHL, tinnitus and vertigo.
o May preceded by history of sudden barometric
pressure change or trauma.
o Can be avoided by instructing the patient post-op
to avoid nose blowing, flying, diving, & lifting heavy
objects.
o Management:
ƒ Revision surgery with careful removal of the
prosthesis.
ƒ Tissue seal is placed over the open oval
window and the prosthesis is replaced.
ƒ Laser is helpful to remove granulation and
scar tissue.

8. Persistent or progressive CHL:

o Most common causes for failure of primary stapes
surgery:
1. Displaced prosthesis (50%).
2. Erosion of incus long process (25%)
3. OS bony regrowth (15%)
4. Adhesions around prosthesis
5. Missed pathology:
x Malleus fixation
x Round window OS
o Management:
ƒ Revision surgery and removal of prosthesis
is associated with a higher incidence of SNHL
and a reduced closure of ABG.
ƒ Hearing aids.

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Riyadh et al. Notes
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o Bone Anchored Hearing Aid (BAHA):
ƒ Option for patients with CHL or MHL who cannot wear HA.
ƒ BAHA bypasses the ossicular chain and amplifies sound that
stimulates the cochlea directly through bone conduction.

o Cochlear Implant (CI):

ƒ Indications:
x Advanced OS with SD scores <30%.
x Advanced OS with CT scan showing grade 2C or 3
regardless the SD score.
ƒ Complications are higher compared patients without OS and
includes:
x Failure of electrode insertion due to basal turn
obliteration.
x Partial electrode insertion due to basal turn obliteration.
x Misplacement of electrode due to basal turn obliteration.
x Facial nerve stimulation in 20% of patients due to
increased conductivity of otospongiotic bone which
required reduction in stimulus levels of the electrodes or
totally deactivating the causative electrodes.
x Reduced performance of the implant due to progressive
otosclerotic changes in the cochlea.

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CPA and Petrous Apex Lesions

- Cerebellopontine Angle (CPA):

- Subarachnoid space (cistern).
- Inverted triangular-shaped.
- Located within lateral posterior fossa.
- Extends into the medial aspect of IAC (Porus Acusticus).
- Contains:
1. CSF
2. Arachnoid tissue
3. CN-VII
4. CN-VIII
5. Anterior inferior cerebellar artery (AICA)
6. Flocculus of the cerebellum
7. Foramen Lushka of 4th ventricle
- Borders:
o Superiorly: Cerebellar tentorium, CN-V
o Anteriorly: Lateral aspect of clivus
o Medially: Brainstem
o Laterally: Petrous bone
o Posteriorly: Cerebellum
o Inferiorly: Cerebellar tonsil, CN IX, X, XI

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- Course of neurovascular structures within CPA:
o Trigeminal nerve (CN-V) travels within the superior portion of CPA
cistern from the lateral pons to the Meckel cave.
o Facial (CN-VII) and Vestibulocochlear (CN-VIII) nerves exit the
brainstem at the lateral ponto-medullary junction adjacent to foramen
of Luschka and travel within the CPA to enter Porus Acusticus.
ƒ CN VII and VIII are encased in glial tissue in CPA.
o Glossopharyngeal (CN-IX), Vagus (CN-X) and Accessory (CN-XI)
nerves extend from the medulla across the inferior aspect of CPA and
enter the pars nervosa of jugular foramen.
o Anterior inferior cerebellar artery (AICA), branch of basilar artery,
takes a variable course within CPA and loops to enter Porus Acusticus.
ƒ Gives a branch, Labyrinthine artery, which travels laterally in
IAC to supply the cochlea and labyrinth.

- Internal Auditory Canal (IAC):

- Directed antero-laterally from CPA cistern.
- Length of 1.2-1.4 cm from Porus Acusticus (medial aspect of IAC) to the
Fundus (lateral aspect of IAC).
- Falciform (transverse) crest:
o Divides the IAC into superior and inferior compartments.
- Bill bar (vertical crest):
o Divides superior compartment into anterior and posterior portions.
o Inferior compartment does not have a bony vertical crest.
- CN VII and VIII are encased in Schwann cells in IAC.
- Obersteiner-Redlich zone is the Glial/Schwann junction.
- Contents (Seven-up Coke-down):
o Anterior-Superior compartment: CN-VII
o Anterior-Inferior compartment: CN-VIII
o Posterior-Superior compartment: Superior vestibular nerve
o Posterior -Inferior compartment: Inferior vestibular nerve

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Riyadh et al. Notes
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- Petrous Apex:
- Pyramid-shaped structure formed by medial portions of temporal bone.
- Its apex is pointing anteromedially and its base located posterolaterally.
- Boundaries:
o Laterally: Inner ear
o Medially: Petro-occipital fissure
o Anteriorly: Petro-sphenoidal fissure and ICA
o Posteriorly: Posterior cranial fossa
- Divided by IAC into:
o Anterior portion:
ƒ Large
ƒ Types of Pneumatization:
x Diploic (filled with bone marrow) in 60%.
x Pneumatized (filled with air cells) in 30%.
o From extension of air cells from mastoid along:
ƒ Infra-labyrinthine.
ƒ Anterior tract
ƒ Superior tract
ƒ Posteromedial tract
ƒ Sub-arcuate tract
o Pneumatization is asymmetric in 10% of
individuals.
x Sclerotic in 10%.
o Posterior portion:
ƒ Small
ƒ Dense otic capsule

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Lateral Skull Base Lesions:

- Classification:
o Intra-Dural:
ƒ Extra-Axial:
x CPA Lesions:
o Vestibular Schwannoma (85%)
o Meningioma (10%)
o Epidermoid (5%)
o Arachnoid Cyst (1%)
o Non-Vestibular schwannomas (1%)
o Others:
ƒ Lipoma
ƒ Aneurysm AICA
ƒ Metastasis
ƒ Intra-Axial:
x Brain tissue lesions:
o Brainstem Glioma (Most common pediatric CPA
lesion).
o Hemangio-blastoma
o Medullo-blastoma
o Extra-Dural:
ƒ Petrous Apex lesions:
x Cholesterol Granuloma
x Epidermoid
x Mucocele
x Petrous apicitis
ƒ Jugular foramen lesions:
x Paragangliomas (Glomus Jugular Tumors)
x Lower Cranial nerves schwannomas.
ƒ Clival lesions:
x Chordoma
x Chondrosarcoma
x Plasmacytoma
o Trans-Dural:
ƒ Clival and temporal bone lesions.

Because lateral skull base lesions cannot be directly visualized, imaging plays a
crucial role in the diagnosis and for patient care, as treatment approaches depend
on the specific disease process and the nearby structures involved.

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CPA Lesions:

- CPA lesions are the most common neoplasms in the posterior fossa.
- Accounts for 10% of all intracranial tumors.
- Intra-dural extra-axial lesions.
- Most CPA lesions are benign:
o Vestibular Schwannoma (85%)
o Meningioma (10%)
o Epidermoid (5%)
o Arachnoid Cyst (1%)
o Non-vestibular schwannomas (1%)
- Primary malignancies or metastatic lesions account for <2% of CPA lesions.

Vestibular Schwannoma (VS):

- Most common CPA tumor (85%).
- Acoustic neuroma is a misnomer:
o Not arise from the cochlear nerve.
o Not a neuroma.
- Epidemiology
o Peak presentation is in the 5th-6th decades.
o When they occur in patients with neurofibromatosis type 2 (NF2),
usually present by the 3rd decade.
ƒ Unilateral VS appearing < age of 30 years mandate close
evaluation of contralateral ear.
o No sex predilection.
- Histopathology:
o Circumscribed encapsulated benign tumor (unlike neuromas).
o Arises from Schwann cells of vestibular portion of CN-VIII.
ƒ Inferior division is more commonly affected by VS (90%).
ƒ Equally affected in Cumming.
ƒ Originated most commonly laterally within IAC in the intra-
canalicular segment of vestibular nerve near Scarpa ganglion.
ƒ Less commonly originated at glial-Schwann cell junction
(Obersteiner-Redlich zone).
o Histologic Types:
ƒ Antoni Type A:
x More cellular.
x Uniform spindle cells.
x Parallel nuclei.
x Arranged in fascicles.
x Verocay bodies.
ƒ Antoni Type B:
x Less cellular.
x Less uniform.
x Looser stroma.
x Cystic degeneration.

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Riyadh et al. Notes
495

- Etiology:
o Sporadic in 95% of cases.
o Associated with Neurofibromatosis type 2 (NF2) in 5% of cases.

- Neurofibromatosis:
- Autosomal dominant inheritance.
- Types:
x NF-1 (von Recklinghausen Disease)
o Mutation in neurofibromin 1 on chromosome 17.
o Most commonly present with cutaneous manifestation.
o 5% risk of unilateral vestibular schwannoma.
o Diagnostic criteria (at least 2 of the following characteristics):
1. ≥ 6 Café-au-lait spots:
ƒ Size > 5 mm in pre-pubertal patients.
ƒ Size > 1.5 cm in post-pubertal patients.
2. ≥ 2 Neurofibromas of any type or ≥ 1 Plexiform neurofibroma.
3. Axillary or groin freckling
4. Optic nerve glioma
5. ≥ 2 Lisch nodules (iris hamartomas)
6. Distinct bony lesions
7. First-degree relative with NF-1

x NF-2 (Central Neurofibromatosis):

o Caused by mutation of NF2 gene (tumor suppressor gene) located on
chromosome 22q12.
ƒ Responsible to encode protein “Merlin/ schwannomin”.
ƒ Absence of Merlin results in promotion of cellular proliferation
and tumorigenesis.
o Early onset <21 years old.
o 95% risk of bilateral vestibular schwannomas.
o Subtypes of NF2:
1. Wishart: Severe type.
2. Gardner: Mild type.
o Diagnostic criteria:
ƒ Bilateral VS.
OR
ƒ First-degree relative with NF-2.
ƒ + One of the following:
x Unilateral vestibular schwannoma
x Any two of meningioma, glioma, schwannoma, or juvenile
cataract.

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Riyadh et al. Notes
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- Pathophysiology of VS:
o Slow-growing tumor within the IAC.
ƒ Growth rate of 1-2 mm/year.
o Typically encroaching and displacing neural structures without direct
invasion.
o Expands medially into the medial aspect of IAC (Porus Acusticus).
o Signs and symptoms of VS depends on its size (Jackler staging):
ƒ Small size VS (≤1 cm).
ƒ Medium size VS (1-2.5 cm).
ƒ Large size VS (2.5-4 cm).
ƒ Giant size VS (> 4 cm).
o Invade the vestibular nerves and compress the cochlear and facial
nerves and the labyrinthine artery:
ƒ Leads to vestibular and cochlear dysfunction.
ƒ However, facial nerve is resilient to dysfunction despite the
compression and thinning of the nerve.
ƒ Facial weakness can be present in large tumors.
o Extension into the CPA leads to compression of cerebellum and
brainstem:
ƒ Causes cranial neuropathy, hydrocephalus and death.
o Very rare malignant potential (<1%).

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- Clinical picture of VS:

o Asymptomatic:
ƒ Diagnosed incidentally on imaging studies for other indications.
ƒ Occurs with:
x Small VS within IAC.
x VS arising in CPA rather than IAC.
o Unilateral symptoms:
ƒ Unilateral (Asymmetrical) SNHL (95%):
x Resulted from VS growth in IAC.
x Progressive high frequency SNHL.
x Up to 20% of patients with VS present with sudden SNHL.
x Only 1-5% of patients with asymmetrical SNHL or sudden
SNHL are having VS.
x Even a sudden SNHL with complete recovery can be
caused by VS.
ƒ Unilateral tinnitus (80%):
x Resulted from VS growth in IAC.
x Only 1-5% of patients with unilateral tinnitus are having
VS.
ƒ Disequilibrium (10%):
x Resulted from VS growth in IAC.
x Mild balance disturbance.
x Tumor extension into the labyrinth may result in episodic
vertigo, similar to Meniere disease.
ƒ Unilateral Facial nerve involvement:
x Resulted from VS growth in IAC.
x Hitselberger’s sign (30-50%):
o Reduced sensation of posterior EAC and concha.
o Compression of Sensory branches of FN (early).
x Facial paresis (Suspect other invasive tumors).
x Motor fibers are more resistant and are affected late.
ƒ Unilateral Trigeminal nerve involvement:
x Resulted from large VS growth in CPA (>3 cm in size).
x Unilateral facial numbness and reduced corneal reflex.
ƒ Unilateral Abducens CNs involvement:
x Resulted from large VS growth in CPA (>3 cm in size).
x Diplopia.
ƒ Unilateral Lower CNs involvement:
x Resulted from large VS growth in CPA (>3 cm in size).
x Unilateral Glossopharyngeal involvement:
o Dysphagia.
x Unilateral Vagus involvement:
o Deviated uvula away from involved side.
o Unilateral VF paralysis.
x Unilateral Spinal Accessory involvement:
o Unilateral shoulder drop.
x Unilateral Hypoglossal involvement:
o Deviated tongue toward the involved side.

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Brun Nystagmus:
ƒ
x Resulted from large VS growth in CPA (>3 cm in size)
compressing ipsilateral cerebellar flocculus.
x Combination of central and peripheral Nystagmus.
x If right CPA tumor:
o Right-beating central nystagmus with right gaze
(toward the lesion).
o Left-beating vestibular nystagmus with left gaze
(away from the lesion).
ƒ Hydrocephalus:
x Resulted from large VS growth in CPA (>3 cm in size).
x Compression and obstruction of 4th ventricle.
ƒ Ataxia:
x Resulted from large VS growth in CPA (>3 cm in size).
x Compression of cerebellum.
ƒ Death:
x Resulted from large VS growth in CPA (>3 cm in size).
x Compression of brainstem.
- Diagnosis of VS:
o Audiology Tests (Initial screening):
ƒ Pure Tone Audiometry (PTA):
x Asymmetric HF-SNHL (65%):
o Average difference of ≥ 15 dB in AC thresholds
between ears at 500, 1000, 2000 and 3000 Hz.
x Sudden SNHL (20%).
x Normal PTA (5%).
ƒ Speech Audiometry:
x Impaired speech discrimination score (SDS) out of
proportion to PTA (even with mild hearing loss).
x Positive for Roll over:
o Paradoxical decrease in SDS with increasing speech
intensity (dB).
ƒ Stapedial (Acoustic) Reflex:
x Absent Reflex or Positive Reflex Decay (90%):
o Inability to maintain the stapedial reflex for a
sustained signal at 10 dB SL for 10 seconds
ƒ Auditory Brainstem Response (ABR):
x Most sensitive and specific audiological test.
x Less sensitive than MRI for small tumors.
x Not considered initial diagnostic tool for VS except in
patients with contraindication for MRI (pacemaker).
x Sensitivity of ABR depends on the size of VS:
o 60-80% sensitive for small VS < 1cm.
o 90% sensitive for medium and large VS.
x Findings indicate Retro-cochlear pathology:
o Abnormal Morphology.
o Delayed inter-aural wave V latency (>0.2 ms).
o Delayed wave I-III latency (>2.0 ms)

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o Vestibular Tests (Not screening tests):
ƒ Videonystagmography (VNG):
x Caloric testing is the most useful component of VNG
testing in VS patients.
o Identify a unilateral vestibular weakness in tumors
that have affected or originate from superior
vestibular nerve.
o Small VS of inferior vestibular nerve may have a
normal caloric response and VNG entirely.
x VNG may add prognostic information by identifying the
nerve of origin when a hearing preservation operation is
considered.
o Theoretically better results may be obtained with
resection of tumors of superior vestibular nerve.
ƒ Vestibular Evoked Myogenic Potential (VEMP):
x Assist in determining the nerve of origin.
x Absent or reduced cVEMP can be demonstrated if VS
originated from inferior vestibular nerve.
x However, normal cVEMP does not rule out the presence of
inferior vestibular nerve tumor.
x Presence of abnormal VEMP response is related more to
the size and ensuing neural compression of tumor within
IAC than by the nerve of origin.

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o Imaging studies:

MRI with gadolinium:
x Gold standard imaging study in evaluation of patients
with suspected VS:
o Asymmetrical SNHL or speech discrimination score.
o Unilateral tinnitus.
x Sensitive to small intra-canalicular VS < 1cm.
x General features:
o Widening of IAC.
o Ice cream cone/Mushroom appearance:
ƒ Tumor filling lAC and extends into CPA.
o Fundal cap:
ƒ Presence of CSF within IAC, lateral to tumor.
ƒ Positively affect hearing preservation
outcomes in middle cranial fossa approach
for tumor resection.
o Form acute angle with the underlying bone.
x MRI Sequences:
o T1:
ƒ HYPO-intense to brain.
o T1 C+ (Most sensitive):
ƒ Marked heterogeneous tumor enhancement.
ƒ Can detect as small VS as 1-2 mm.
o T2:
ƒ HYPER-intense to brain.
ƒ HYPO-intense to CSF.
o Heavily T2 Fast-Spin Echo (FSE):
ƒ Achieve the accuracy of contrasted T1
without the need for contrast.
x Tumor size measurement:
o Standard documentation of tumor size is recording
the linear measurements in 3 dimensions.
o Tumor volume measurement is more sensitive in
monitoring small changes of tumor growth
overtime.
ƒ CT with Contrast:
x Provide adjunctive information regarding bony structures
surrounding CPA lesions.
x Not ideal as screening test for evaluation of CPA lesions:
o Can miss lesions < 1cm.
x Indicated in suspected VS patients who can’t undergo MRI
or if MRI is unavailable.
x Findings:
o Heterogeneous contrast-enhanced mass in IAC.
o Expansion of IAC (Average IAC width is 5mm).
o Acute angles at the bone-tumor interface.

- Intracanalicular tumors and tumors extending less than 5 mm

into the CPA frequently are missed with contrasted CT

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- Treatment of VS:
o Observation with serial imaging
ƒ Indications:
1. Asymptomatic patients.
2. Small tumors without brainstem compression.
3. Only hearing ear.
4. Elderly (>65 years).
5. Non-operative patients.
ƒ Goal:
x At the time of diagnosis, rate of tumor growth is unknown
and unpredictable.
x Observation allows enough time to determine the tumor
growth rate, and if no growth is demonstrated, treatment
is not necessary.
x Hearing aids are used when appropriate.
ƒ Follow-up plan:
x Initially with MRI after 6 months then annually if no
growth was detected with volumetric measurements.
x Indication of intervention:
o Rapid tumor growth (>2.5 mm/year) regardless of
tumor size.
ƒ Advantages:
x Afford years of residual hearing.
x Avoid the complications of the intervention.
ƒ Disadvantages:
x Deterioration of hearing loss during the observation
period and the opportunity for hearing-preservation
approach may be lost.

o Stereotactic Radiation (Radiosurgery):

ƒ Administration of radiation (13-14 Gy) to a precise location.
ƒ Induce radiation damage to the target area while minimizing the
effect to the adjacent structures.
ƒ Modalities:
x Gamma Knife
x Cyber Knife
ƒ Goals:
x Provide long-term tumor growth control (90-100%).
o No radiographic enlargement over 2 mm in tumor
diameter or 10% change in tumor volume.
x Avoid the risk of surgical intervention.
x Prevent acute loss of neurologic function.
ƒ Indications:
1. Tumors < 2-3 cm.
2. Recurrence after surgery.
3. Only hearing ear.
4. Elderly (>65 years).
5. Non-operative patients.

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ƒ Advantages:
x Avoid morbidity of surgical intervention.
x Rapid return to normal activity.
ƒ Disadvantages:
x Stop the growth without removing the tumor.
x No pathologic diagnosis.
x Post-radiation scarring makes salvage surgery difficult.
x Risk of post-radiation tumor expansion:
o Occurs in 25% of patients.
o Transient tumor swelling (2-4 mm).
o May take 6 months to 5 years to resolve.
o Increase the risk of complications.
x Complications:
o Hearing loss:
ƒ Occurs gradually months to years later.
ƒ Due to radiation of the cochlea.
ƒ Maintaining a cochlear dose < 6.9 Gy is
important in preserving residual hearing.
ƒ Hearing preservation rate 50-86%.
o Chronic vestibular dysfunction:
ƒ Present in 15-25% of patients.
o Facial and trigeminal neuropathies:
ƒ 0-5% of patients.
ƒ Risk increase with doses > 13 Gy.
o Hydrocephalus:
ƒ Without evidence of tumor growth.
ƒ Occurs in up to 5% of patients.
ƒ More common with large tumors due
proteinaceous debris obstruction of CSF flow.
o Radiation-induced Malignancy:
ƒ In young patients.
ƒ 1:1,000 risk over 5-30 years period.
ƒ Follow up plan:
x Post-irradiation MRI scans are obtained initially after 6
months and then annually to observe the effect of the
stereotactic radiation.
x After radiation, tumors show signs of treatment effect by
loss of central enhancement within the first 6-12 months
which correlate with tumor necrosis.

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o Microsurgery:
ƒ Indications:
1. Tumors > 2-3 cm.
2. Recurrence after stereotactic radiation.
ƒ Goals:
x Complete tumor resection, tumor de-bulking or lAC
decompression.
x Preserving facial nerve and auditory function if present
preoperatively.
ƒ Surgical approaches for CPA lesions depends on:
x Hearing status.
x Tumor size.
x Tumor location.
x Facial nerve status.
ƒ Types of Surgical approaches for CPA lesions:
x Hearing preservation approaches:
o Candidate:
1. Patients with:
x Serviceable hearing:
o Grade A ASHA:
- PTA ≤ 30 dB and SDS ≥70%
o Grade B ASHA:
- PTA ≤ 50 dB and SDS ≥50%
x Tumor size < 2 cm.
2. NF2
3. Only hearing ear.
o Examples:
1. Middle Cranial Fossa
2. Retrosigmoid/Suboccipital
x Non-Hearing preservation approaches:
o Candidate:
1. Non-serviceable hearing (ASHA grade C or
worse).
2. Tumors > 2 cm.
o Examples:
1. Trans-labyrinthine.
2. Trans-otic/Trans-cochlear.
3. Combined approach (Trans-labyrinthine and
Retro-sigmoid/Sub-occipital).

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o Trans-Labyrinthine Approach:
ƒ Non-hearing preservation approach.
ƒ Most common approach for resection VS.
ƒ Indications:
1. Non-serviceable hearing (Grade C or worse) with
any tumor size.
2. Large Tumor size > 2 cm:
o Hearing in large tumors is unlikely to be preserved
by any approach.
o Trans-labyrinthine approach carries the highest
rate of preservation of facial nerve function.
ƒ Contraindications (By Dr.Shami):
1. Only hearing ear.
2. Ipsilateral cholesteatoma.
ƒ Steps:
x Trans-mastoid labyrinthectomy and skeletonization of
sigmoid sinus and posterior fossa dura.
o Permit identification of facial nerve with wide
exposure of IAC and CPA.
x De-bulking and resection of the tumor.
x Eustachian tube closure.
x Subtotal petrosectomy, cavity obliteration, and blind sac
closure of the external auditory canal.
ƒ Advantages:
x Most direct route.
x Excellent exposure.
x Not limited by tumor size.
x Minimal cerebellar retraction.
x Highest rate of facial nerve preservation (98%).
o Superior exposure of entire course of facial nerve.
o Preservation rate is lower with tumor size >1.5 cm.
o Immediate repair of facial nerve is possible.
ƒ Disadvantages:
x Sacrifices the hearing.
x Extent of mastoid pneumatization may constrict the
surgical field.
x Risk of CSF leak from the wound.

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o Trans-Cochlear Approach:
ƒ Non-hearing preservation approach.
ƒ Extension of trans-labyrinthine approach obtained by
displacement of facial nerve posteriorly and removal of the
cochlea to provide surgical access anteriorly.
ƒ Indications:
1. Extensive lesions of petrous apex and clivus.
ƒ Advantages:
x Wide exposure of skull base with access to petrous apex
and clivus.
ƒ Disadvantages:
x Sacrifices the hearing.
x Risk of temporary facial nerve paralysis.

o Trans-Otic Approach:
ƒ Non-hearing preservation approach.
ƒ Similar to Trans-Cochlear approach but not involving
transposition of facial nerve.
ƒ Advantages:
x Less risk of facial nerve weakness compared to trans-
cochlear approach.
ƒ Disadvantages:
x Sacrifices the hearing.
x Limited exposure compared to trans-cochlear approach.

o Combined Approach:
ƒ Non-hearing preservation approach.
ƒ Indications:
1. Large CPA tumor size > 4 cm
ƒ Steps:
x Trans-labyrinthine with Retro-sigmoid/Sub-occipital
facilitate exposure for resection large CPA tumors.
x Extension of tumor anteriorly to petroclival region may
requires addition of Trans-cochlear approach.

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o Middle Cranial Fossa Approach:
ƒ Hearing preservation approach.
ƒ Indications:
1. Serviceable hearing and lateral intra-canalicular
tumor with minimal CPA involvement (<2 cm).
ƒ Steps:
x Temporal craniotomy permits exposure of IAC after
identification of superior SCC and geniculate ganglion.
ƒ Advantages:
x Highest rate of hearing preservation (80%).
x Lowest rate of CSF leak.
x No intra-dural drilling:
o Low rate of post-operative headache compared to
Retro-sigmoid/Sub-occipital Approach.
ƒ Disadvantages:
x Limited to small lateral intra-canalicular lesions.
x More difficult technically.
x Poor exposure to posterior fossa.
x Requires temporal lobe retraction:
o Risk of aphasia or seizure.

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o Retro-sigmoid/Sub-occipital Approach:
ƒ Hearing preservation approach.
ƒ Indications:
1. Serviceable hearing and CPA or medial intra-
canalicular tumors of any size.
ƒ Steps:
x Trans-mastoid decompression of sigmoid sinus and retro-
sigmoid craniotomy permit access to CPA tumors without
disturbing the labyrinth.
x Permits direct access to the medial two thirds of IAC while
preserving the inner ear.
ƒ Advantages:
x Hearing preservation (30-60%).
x Provide the most panoramic view of posterior fossa.
x Deals with tumors of any size in CPA or medial IAC.
ƒ Disadvantages:
x Limited exposure to lateral IAC.
x Highest rate of CSF leak.
x Highest rate of facial nerve injury.
x Highest rate of post-operative headache (10-30%).
o Intra-dural spread of bone dust from intra-dural
drilling.
x Highest rate of air embolism:
o Through diploic veins in skull into jugular system
and sigmoid sinus.
x Requires cerebellar retraction:
o Risk of postoperative imbalance.

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- Hearing Rehabilitation:
o Options of hearing rehabilitation after non-hearing preservation
surgery of unilateral VS:
ƒ Contralateral routing of signals (CROS) hearing aid.
ƒ Bone-anchored hearing aid (BAHA).

- Treatment plan for NF2:

o Preservation of hearing is vital.
o Early detection and intervention provide long-term functional hearing.
o Consider screening the family with audiometry and MRI.
o Approach:
ƒ Surgical resection of the larger VS first:
x Consider hearing preservation approach:
o Retro-sigmoid/sub-occipital or Middle cranial fossa
approaches.
x If cochlear nerve was preserved intra-op:
o Consider cochlear implantation.
x If cochlear nerve was sacrificed intra-op:
o Consider Auditory brainstem implant (ABI).
ƒ If hearing was preserved in the previously operated side:
x Consider surgical removal of the second tumor.
ƒ If hearing couldn’t be preserved in the previously
operated side:
x Consider observation for the second tumor with serial MRI
strategy.
x Consider stereotactic radiation for the second tumor.

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Riyadh et al. Notes
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- Post-operative complication:
o Hearing loss:
ƒ Hearing preservation is low with any approach if tumor size is
more than 2 cm.
ƒ Highest rate of hearing preservation is with middle cranial fossa
approach (80%).
o Facial weakness:
ƒ Post-op facial nerve function is dependent on:
x Size of tumor
x Adherence of tumor to facial nerve
x Experience of surgical team.
ƒ Highest rate of facial nerve preservation is with trans-
labyrinthine approach.
ƒ Highest rate of facial nerve injury is with retro-sigmoid/sub-
occipital approach.
ƒ Facial nerve transection ideally is managed by immediate repair
or with an interposition graft.
o CSF leak:
ƒ Reported from 1-10% of all cases.
ƒ Highest rate of CSF leak is with retro-sigmoid/sub-occipital
approach.
o Headache:
ƒ Highest rate of postoperative headache is with retro-
sigmoid/sub-occipital approach.
ƒ Secondary to intra-dural spread of dust as a result of intra-dural
drilling.
o Meningitis:
ƒ Serious concern in postoperative period.
ƒ Mean time of onset is 8 days postoperatively.
ƒ Rate of 1-10% of all cases.
o Recurrence of tumor:
ƒ Rate of <1% of all cases.
o Mortality:
ƒ Rate of <1% of all cases.

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Meningioma:
- 2nd most common CPA tumor (10%).
- Most common intracranial extraaxial tumor
o Constitutes up to 20% of all primary intracranial tumors.
- Epidemiology
o Most common in middle-age women.
o More common in female (2:1).
o Peak presentation is in the 5th-6th decades.
- Histopathology:
o Arises from the arachnoid villi cap (endothelial) cells.
o Grossly, appears as globular mass firmly adherent to the dura mater.
o Has characteristic speckles scattered throughout the tumor,
corresponding to the microscopic psammoma bodies.
o WHO histopathologic classifications:
1. Grade I (Benign):
x Most common form (90%).
x Display whorls of spindle cells with presence of calcified
psammoma bodies.
x Variants: Meningothelial, fibrous, transitional
psammomatous and angiolastic.
2. Grade II (Atypical):
x Forms 7% of all meningiomas.
x Display increased cellularity, atypical nuclei and areas of
necrosis.
x Variants: Choroid, clear cell.
3. Grade III (Anaplastic/Malignant):
x Forms 2% of all meningiomas.
x Display high proliferation indices with brain invasion.
x Variants: Papillary, rhabdoid, anaplastic.
- Etiology:
o Sporadic in most cases.
o Associated with Neurofibromatosis type 2 (NF2) in some cases.
- Pathophysiology:
o Benign but locally aggressive encapsulated tumors.
ƒ Displaces but does not invade adjacent neural tissue.
ƒ Invades the adjacent bone by extension along haversian canals
(without destruction).
ƒ Adjacent bone is hyperostotic in 25% of cases.
o Occurs at different anatomic sites:
ƒ Para-sagittal region (Most common location).
ƒ Falx
ƒ Convexity
ƒ Tuberculum sellae
ƒ Sphenoid ridge
ƒ Petrous face (CPA)
ƒ Tentorium
ƒ Clivus

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o Posterior fossa meningiomas arise outside the IAC on either:
ƒ Posterior surface of petrous bone.
ƒ Along the sigmoid sinus.
o Because they arise outside the IAC, become large before they produce
signs and symptoms of CN-VIII compression (late presentation).

- Clinical picture:
o Similar to VS:
ƒ Small tumors:
x Hearing loss, tinnitus and imbalance.
ƒ Larger tumors
x Involvement of other cranial nerves and hydrocephalus.
- Diagnosis:
o Audio-vestibular Tests:
ƒ Similar findings of VS once CN-III is compressed.
ƒ Cannot distinguish between VS and meningiomas.
ƒ Low sensitivity of detecting meningiomas compated to VS
because meningiomas do not originate within IAC.
o Imaging:
ƒ Most important tool in the diagnosis.
ƒ CT scan with contrast:
x Homogeneous enhanced tumors (compared to VS).
x Areas of calcifications (25%).
x Bony hyperostotic changes.
ƒ MRI with Gad:
x General features:
o No widening of IAC.
o Broad dural base enhancement.
o Dural tail:
ƒ Extension of enhancement along underlying
dural surface (50-75%).
o Form obtuse angle with the underlying bone.
o Tumor progression may result in erosion of cranial
base and invasion into neural foramina or the
middle ear.
x T1:
o HYPO-intense to brain.
x T1 C+:
o Heterogeneous enhancement
ƒ More heterogeneous than VS.
ƒ Less marked enhancement than VS.
x T2:
o Variable intensity.

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- Treatment (Similar to VS):

o Observation with serial imaging
ƒ Indications:
1. Small tumors in asymptomatic patients.
2. Only hearing ear (?)
3. Elderly (>65 years).
4. Non-operative patients.

o Stereotactic Radiation (Radiosurgery):

ƒ Indications:
1. Recurrence after surgery.
2. Only hearing ear (?)
3. Elderly (>65 years).
4. Non-operative patients.

o Microsurgery:
ƒ Gold standard treatment for meningioma with progressive
symptoms.
ƒ Similar approaches as for VS.
ƒ Complete resection is not always feasible.
ƒ Decompression of surrounding neurovascular structures
provides:
x Symptomatic relief
x Tissue for histopathologic diagnosis.

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Primary Cholesteatoma (Epidermoid):
- 3rd most common CPA tumor (5%).
- Histopathology:
o Stratified squamous epithelial lining surrounds a desquamated keratin.
- Etiology:
o Congenital, originates from epithelial rests within the CPA or the
temporal bone (Most common).
o Acquired, from extension from the mastoid, middle ear, or petrous.
- Pathophysiology:
o Benign slow-growing lesions, expanding into areas of least resistance.
ƒ Tend to erode surrounding bone and encase neurovascular
structures.
ƒ Produce variable shapes with irregular surfaces.
ƒ May extend in dumbbell pattern into middle cranial fossa.
o As the lesions expand, compression and irritation of surrounding
structures produce the signs and symptoms, which will be apparent at
the second to fourth decades.
- Clinical picture:
o Similar to VS:
ƒ Distinguishing clinical manifestations:
x Facial twitching.
x Progressive facial paralysis (earlier presentation).
- Diagnosis:
o Audio-vestibular Tests:
ƒ Similar findings of VS once CN-III is compressed.
ƒ Cannot distinguish between VS and epidermoid.
o Imaging:
ƒ Most important tool in the diagnosis.
ƒ CT scan with contrast:
x Hypodense irregular lesions.
x No enhancement with intravenous contrast.
x Remodeling of surrounding bone.
ƒ MRI with Gad:
x T1:
o HYPO-intense to brain.
x T1 C+:
o NO enhancement
o Unlike VS, meningiomas and chondromas.
x T2:
o HYPER-intense to brain.
x Fluid-Attenuated Inversion Recovery (FLAIR):
o HYPER-intense to CSF.
o Unlike arachnoid cysts.
x Diffusion-weighted Imaging (DWI):
o HYPER-intense to brain (Restricted diffusion).
o Unlike arachnoid cysts.

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- Treatment:
o Microsurgery :
ƒ Gold standard treatment for epidermoids.
ƒ Similar approaches as for VS.
ƒ Complete resection is not always feasible.
ƒ Lesions that envelop vital neurovascular structures can be
managed with subtotal resection and monitored with imaging
since these are slowing growing lesions.
ƒ Recurrence rates of:
x 23% after total resection.
x 27% after subtotal resection.
ƒ Majority of recurrences required surgical intervention.

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Arachnoid Cysts:
- Account for 1% of tumors within CPA.
- Congenital malformation of arachnoid result in sac filled with normal CSF.
- Typically asymptomatic but can cause compression of CN-VII and VIII.
- Smooth lesions displacing neurovascular structures without invasion.
- Imaging (Iso-intense to CSF):
o T1: HYPO-intense.
o T1 C+: Non-enhancing.
o T2: HYPER-intense.
o FLAIR: HYPO-intense.
o Diffusion weighted: HYPO-intense (No restricted diffusion).
- Treatment:
o Observation if asymptomatic.
o Decompression via suboccipital approach for symptomatic cysts.

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Non-Vestibular Schwannomas:
- Account for 1% of tumors within CPA.
- More common in NF2 patients.
- Schwannomas may arise on any other cranial nerve in the posterior fossa:
o Trigeminal (2nd most common after CN-VIII).
o Facial
o Glossopharyngeal
o Vagal
o Accessory
o Hypoglossal
- On imaging studies, Non-VS have the same characteristics as those of VS
except for their location.
- Distinguished by their different location and by symptoms of dysfunction of
cranial nerve of origin.
- Specific features on Non-VS:
o Trigeminal Schwannomas:
ƒ Most common non-vestibular schwannomas.
ƒ Arise either:
x Intra-durally:
o From the nerve root in CPA and Meckel cave.
x Extra-durally:
o From gasserian ganglion in middle cranial fossa.
ƒ Symptoms:
x Ipsilateral facial hypesthesia in CN-V distribution.
ƒ CT imaging:
x Enhancing expansion of Meckel cave or foramen lacerum.
ƒ MRI imaging
x Enhancing lesion in anterior-posterior orientation adjacent
to Meckel cave.
x May be difficult to distinguish from a meningioma.
ƒ Treatment:
x Lesions extending into Meckel cave can be treated with
radiation or can be resected through the anterolateral
intradural approach (Dolenec's) and anterior petrosal
approach.

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o Facial Schwannomas:
ƒ May arise anywhere along the course of the facial nerve.
x CPA is involved in more than 50% of tumors.
x Difficult to distinguish from VS if limited to IAC.
ƒ Symptoms:
x Facial weakness if tumor is very large (unlike FN
hemangioma).
x Facial twitching:
o Distinguish it from VS but NOT from Epidermoid.
ƒ Electroneuronography (ENoG):
x Reduced in facial nerve schwannomas even when no
facial weakness or tic is present.
x Normal in VS until the tumor becomes very large.
ƒ CT imaging:
x Erosion of IAC or labyrinthine facial nerve canal.
x Expansion of geniculate ganglion and fallopian canal.
ƒ MRI imaging
x Enhancing dumbbell-shaped expansion of intra-temporal
facial nerve.
x Enhancing expansion of geniculate ganglion region.
ƒ Treatment:
x Observation for Grade I-III HB.
x Surgical decompression for declining facial nerve
function via middle fossa or trans-mastoid approaches.
x Resection and cable grafting for nonfunctional facial
nerve (Grade V-VI HB).

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o Lower CNs Schwannomas:
ƒ Typically involve the inferior aspect of posterior fossa.
ƒ Symptoms:
x Related to the nerve of origin but expansion of tumor may
affect all of lower cranial nerves.
x Residual hearing is more likely to be preserved with lower
cranial nerve neuromas compared to VS.
ƒ Imaging:
x Enhancing lesion of the CPA.
x Expansion of jugular foramen (CN-IX-X-XI).
x Expansion of hypoglossal canal (CN-XII).
ƒ Treatment:
x Similar to VS.

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Lipomas:
- Account for 1% of tumors within CPA.
- Congenital malformation resulting in hamartomatous collections of mature
adipose tissue.
- Grow very slowly and induce similar symptoms to other CPA lesions.
- Smooth lesions displacing neurovascular structures without invasion.
- Imaging:
o T1: HYPER-intense.
o T1 C+: Non-enhancing.
o T2: HYPER-intense.
o Post-contrast Fat-suppressed T1: HYPO-intense.
- Treatment:
o Observation if asymptomatic.
o Decompression via suboccipital approach for symptomatic lesions.

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Petrous Apex Lesions:

- Extra-dural lesions.
- Most common petrous apex lesions:
o Cholesterol Granuloma
o Epidermoid
o Mucocele
o Petrous apicitis

- Normal variants of petrous apex (Leave Me Alone):

o Asymmetric Petrous Apex
o Petrous Apex Effusion

- Imaging of Normal Petrous Apex:

- T1:
o Diploic: HYPER-intense to Brain.
o Pneumatized or sclerotic: HYPO-intense to Brain.
- T1 C+:
o Diploic: No enhancement.
o Pneumatized or sclerotic: No enhancement.
- T2:
o Diploic: HYPO-intense to Brain.
o Pneumatized or sclerotic: HYPO-intense to Brain.
- Fat-Suppression:
o Diploic: HYPO-intense to Brain.
o Pneumatized or sclerotic: HYPO-intense to Brain.

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Cholesterol Granuloma:
- Most common petrous apex lesions.
- Slow-growing expansile cystic lesion.
- Occur 20 times more frequently than epidermoids.
- Uncommon compared to VS.
- Etiology:
o Long-standing history of otitis media in a patient with well-
pneumatized petrous apex.
- Pathophysiology:
o Occlusion of air cell system results in accumulation of secretions and
hemorrhage into the air cells followed by foreign body reaction and
progressive granuloma formation.
o Contains viscous brown fluid, granulation tissue, and cholesterol
crystals, which are often contained within a thick fibrous capsule that
lacks a true epithelial lining.
- Clinical picture:
o Similar to VS with the extension of the mass into the CPA.
o Gradenigo’s syndrome:
ƒ Otorrhea.
ƒ Lateral rectus palsy.
ƒ Trigeminal/retroorbital pain.

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- Imaging:
o CT Scan:
ƒ General features:
x Smooth, round and expansive isodense lesion.
x NO enhancement with contrast (may have rim-
enhancement).
x Highly pneumatized contralateral petrous apex.
o MRI:
ƒ T1:
x HYPER-intense to brain.
x Unlike Epidermoids.
ƒ T1 C+:
x No Enhancement.
ƒ T2:
x HYPER-intense to brain.
ƒ Fat-suppression:
x HYPER-intense to brain.
x Unlike asymmetric penumatization.
- Treatment:
o Observation:
ƒ For asymptomatic lesions.
o Drainage:
ƒ For symptomatic lesions.

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Epidermoid (Petrous Bone Cholesteatoma):
- Accounts for 10% of all petrous apex lesions.
- Most commonly are congenital.
- Similar to CPA Epidermoid.
- Moffat-Smith classification of Petrous Bone Cholesteatoma:
1. Supra-labyrinthine
2. Supra-labyrinthine-apical
3. Infra-labyrinthine
4. Infra-labyrinthine-apical
5. Massive-labyrinthine
6. Massive-labyrinthine-apical
7. Apical

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- Imaging:
o CT scan with contrast:
ƒ Hypodense smooth expansile lesions.
ƒ No enhancement with intravenous contrast.
ƒ Remodeling of surrounding bone.
o MRI with Gad:
ƒ T1:
x HYPO-intense to brain.
x Unlike cholesterol granulomas.
ƒ T1 C+:
x NO enhancement
ƒ T2:
x HYPER-intense to brain.
ƒ Diffusion-weighted Imaging (DWI):
x HYPER-intense to brain (Restricted diffusion).
x Unlike cholesterol granulomas.

- Treatment:
o Surgical excision

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Petrous Apex Mucocele:
- Uncommon.
- Resulted from post-inflammatory obstruction of a pneumatized petrous apex
air cells.
- Imaging:
o CT scan with contrast (Similar to Cholesterol granuloma):
ƒ Smooth, round and expansive hypodense lesion.
ƒ NO enhancement with contrast.
ƒ Highly pneumatized contralateral petrous apex.
o MRI with Gad:
ƒ T1:
x HYPO-intense to brain.
x Unlike cholesterol granulomas.
ƒ T1 C+:
x NO enhancement
ƒ T2:
x HYPER-intense to brain.
ƒ Diffusion-weighted Imaging (DWI):
x HYPO-intense to brain (NO restricted diffusion).
x Unlike epidermoids.

- Treatment:
o Observation:
ƒ For asymptomatic lesions.
o Drainage:
ƒ For symptomatic lesions.

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Petrous Apicitis:
- Uncommon.
- Infectious process caused by medial extension of acute otitis media into a
pneumatized petrous apex.
- Imaging:
o CT scan with contrast:
ƒ Irregular destruction of petrous apex.
ƒ No expansion.
o MRI with Gad:
ƒ T1:
x HYPO-intense to brain.
ƒ T1 C+:
x Enhancement
ƒ T2:
x HYPER-intense to brain.

- Treatment:
o Medical management:
o Surgical drainage:
ƒ If not responding to medical management.

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Asymmetric Petrous Apex:
- Normal variant.
- Petrous apex pneumatization is asymmetric in up to 10% of patients.
- HYPER-intense fatty marrow may be mistaken for a cholesterol granuloma
on T1-weighted images.
- Differentiated from cholesterol granuloma by:
o Normal trabeculated petrous apex on CT.
o Lack of mass effect.
o HYPO-intense on fat suppression MRI.

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Petrous Apex Effusion:
- As in the mastoids, effusions can develop within pneumatized petrous apex
cells and can occasionally mimic masses.
- Differentiated from masses by:
o Normal trabeculated petrous apex on CT.
o Lack of mass effect.
o T1: HYPO-intense (unlike cholesterol granulomas).
o T1 C+: No enhancement.
o T2: HYPER-intense (similar to CSF intensity).

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Surgical Approach to Petrous Apex lesions:
- Depends on:
o Available air-cell pathways:
ƒ Below, above, posterior and anterior to the labyrinth.
o Portion of petrous apex involved:
ƒ Anterior or Posterior.
o Hearing status:
ƒ Sparing the otic capsule surgically is preferred in patients with
serviceable hearing.

- Surgical approaches for Posterior Petrous Apex lesions:

o Hearing preservation approaches:
ƒ Infra-labyrinthine approach
ƒ Retro-labyrinthine approach
ƒ Subarcuate approach
o Non-hearing preservation approaches:
ƒ Trans-labyrinthine approach.

- Surgical approaches for Anterior Petrous Apex lesions:

o Hearing preservation approaches:
ƒ Extended middle cranial fossa approach
ƒ Glenoid fossa approach
ƒ Infra-cochlear approach
ƒ Endoscopic trans-sphenoid approach (for Drainage)
ƒ Infra-temporal approach (Fisch type A-B)
o Non-hearing preservation approaches:
ƒ Trans-otic/Trans-cochlear approaches.

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Jugular Foramen Lesions:

- Extra-dural lesions.
- Most common JF lesions:
o Paraganglioma (Glomus Tumor)
o Lower Cranial Nerves Schwannoma

Paraganglioma (Glomus Tumor):

- 2nd most common temporal bone tumor (after VS).
- Most common vascular tumor of temporal bone.
- Most common Jugular Foramen Lesion.
- Epidemiology:
o Peak presentation is in the 4th-6th decades.
o Familiar paragangilomas present earlier.
o More common in females (3:1).
- Histopathology:
o Benign tumor of neuroendocrine paraganglial chemoreceptor cells
originating from neural crest cells adjacent to CN-IX and X.
o Contain nests of non-chromaffin-staining cells (Zellballen) septated by
a prominent fibrovascular stroma.
o Typically non-functional tumors but capable of clinically significant
catecholamine secretion (norepinephrine) in (5%) of patients:
ƒ Causing paroxysmal hypertension, headache and palpitations.

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- Pathophysiology:
o Slow-growing locally destructive tumors.
o Invade neurovascular structures of skull base.
o Follow the path of least resistance.
o Distributed along parasympathetic nerves in skull base and neck.
o Occur more frequently on the left side.
o Commonly supplied by the ascending pharyngeal artery.
- Rule of 10:
o 10% are Familiar:

Autosomal dominant. “Mutations of mitochondrial succinate dehydrogenase”
ƒ Present earlier.
ƒ More aggressive.
ƒ More commonly multifocal (50%).
ƒ More commonly secrete vasoactive substances.
o 10% are Multiple.
o 10% in Pediatric.
- Classification of Glomus tumors:
1. Carotid Body Tumor (Glomus Caroticum):
ƒ Most common type in the head and neck (70%).
ƒ Arises from carotid body.
ƒ Typically does not involve the temporal bone.
2. Glomus Jugulare:
ƒ Most common type in the temporal bone.
ƒ Arises from adventitia of jugular bulb in the jugular foramen.
3. Glomus Tympanicum:
ƒ Arises from the promontory along the course of Jacobson’s
nerve (tympanic branch of CN-IX).
ƒ Confined to middle ear space.
ƒ Present early with pulsatile tinnitus and CHL.
4. Glomus Vagale:
ƒ Arises from paraganglia around the Vagus nerve at skull base.

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- Clinical picture (Jugulotympanic Paragangliomas):

o Symptoms of the mass:
ƒ Pulsatile tinnitus (Most common symptom).
ƒ Conductive hearing loss.
ƒ Aural fullness.
ƒ Dizziness.
ƒ Bloody otorrhea.
ƒ Facial weakness.
ƒ Multiple cranial nerve palsies (CN IV–XII):
x Jugular foramen syndrome/Vernet syndrome:(CN IX–XI).
x Villaret’s syndrome (CN IX–XII + sympathetic chain).
x Collet Sicard syndrome (CN IX–XII).

o Symptoms of secreting tumors:

ƒ Labile hypertension
ƒ Palpitations
ƒ Flushing
ƒ Diaphoresis
ƒ Diarrhea

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o Signs:
ƒ Reddish-blue pulsatile mass medial to the inferior TM.
x Brown’s sign:
o Blanching of the mass with positive pressure on
pneumatic otoscopy.
:x Aquino’s sign
o Decreasing of the pulsation of the mass with
ipsilateral carotid artery compression.
ƒ Hemorrhagic aural polyp in extending in EAC.
ƒ Auscultation over the mastoid or infra-auricular area reveals an
audible bruit.

phelps sign:
Erosion of the caroticojugular spine between the carotid canal and
jugular fossa in CT

Otoscopy:
– Red reflex through intact tympanic membrane.
– Rising sun appearance: When tumor arises from the floor of middle ear.
– Tympanic membrane may appear bluish and bulging.
– Pulsation sign (Brown’s sign): On increasing the ear canal pressure with
Siegle’s speculum, tumor pulsates vigorously and then blanches. Reverse
happens with release of pressure.

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- Diagnosis (Jugulotympanic paragangliomas):

o 24-hours urine catecholamine screen:
ƒ For vanillylmandelic acid and metanephrine.
ƒ Used as screening test for actively secreting paragangliomas.
o CT with contrast:
ƒ Marked contrast enhancement.
ƒ Characteristic bone destruction (Moth-eaten pattern):
x Erosion of jugulo-tympanic spine.
x Enlargement of jugular foramen with irregular bony
destruction.
x Involvement of middle ear and mastoid.
o MRI with Gad:
ƒ Goals:
x Confirm the diagnosis.
x Identify intracranial extension and differentiate between
intra-dural and extra-dural extension.
x Detection of concurrent paragangliomas.
ƒ T1:
x HYPO-intense to brain.
ƒ T1 C+:
x Marked enhancement.
ƒ T2:
x Salt and pepper appearance:
o Pepper: High-flow signal voids of feeding arteries.
o Salt: Subacute hemorrhage within the tumor.
o Angiography:
ƒ Assist in the diagnosis and for pre-operative embolization.
o Radionudide Imaging:
ƒ Indium octreotide scanning (111 In-octreoscan):
x 90% specificity and sensitivity in detecting head and neck
paragangliomas.
x Very effective to screen for secondary tumors.
x Effective postoperatively to screen for recurrent disease.
ƒ 123 I-metaiodobenzylguanidine (MIBG):
x Shows similar sensitivities and specificities to octeroscan.
ƒ 18 F-PDG-PET:
x Best for evaluation of malignant and metastatic
paragangliomas.
x Sensitivities of 74-88%.

Diagnostic biopsy is contraindicated

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- Staging (Jugulotympanic paragangliomas):

o Two surgical classification systems are used pre-operatively based on
the radiographic findings:
o Fisch classification system:
ƒ Doesn’t differentiate between tympanic and jugular
paragangliomas.

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Riyadh et al. Notes
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o Glasscock-Jackson classification system,
ƒ Differentiate between tympanic and jugular paragangliomas.

- Treatment (Jugulotympanic paragangliomas):

o Microsurgery:
ƒ Traditional treatment for head and neck paragangliomas.
ƒ Fisch infratemporal fossa approaches were developed to
specifically resect temporal bone paragangliomas.
ƒ Pre-operative embolization is useful adjunct in large tumors.
x Leads to tumor shrinkage and decreased intraoperative
bleeding which helps in doing complete surgery.
x Surgery should be done within 48 hours to avoid
recruitment of collateral circulation.
ƒ Anesthesia requirements should take into consideration actively
secreting tumors, which require alpha and beta adrenergic
blockade.

Management includes preoperative embolization, surgery and radiotherapy.

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o Glomus Tympanicum (Fisch class A):
ƒ Small tumors confined to the middle ear cavity.
ƒ Approached by trans-canal/inferiorly based tympanomeatal flap:
x Embolization is not required.
x Bipolar electrocautery microforceps can be used to shrink
the tumor and resect it.
o Jugulotympanic paragangliomas (Fisch class B):
ƒ Large tumors without involvement of jugular bulb or
jugulocarotid spine.
ƒ Approached by combined post-auricular/end-aural approach:
x CWU mastoidectomy and extended facial recess.
x Sacrifices chorda tympani and remove the vaginal process
of tympanic bone to expose the hypotympanum.
o Jugulotympanic paragangliomas (Fisch class C and D):
ƒ Large tumors with involvement of jugular bulb or intracranial
extension.
ƒ Approached by Fisch Type A infratemporal fossa approach:
x Extended mastoidectomy with removal of EAC, TM,
malleus and incus.
x Carotid artery is skeletonized.
x Tumor is removed from carotid, middle ear and
sigmoid/jugular bulb/jugular vein.
x ET tube should be permanently occluded to avoid
postoperative CSF rhinorrhea.
x Intracranial extension is addressed by:
o Opening the dura in pre-sigmoid area down to
tumor extension at the level of jugular bulb.
x Petrous apex extension is addressed by:
o Trans-labyrinthine/Trans-cochlear approach.

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- Fisch Type A:
o Allows access to lesson of jugular foramen and anterior petrous apex.
o Indications:
ƒ Types C and D glomus jugulare tumors.
ƒ Petrous apex epidermoids.
- Fisch Type B:
o Allows access for lesions of anterior petrous apex and mid-clivus.
- Fisch Type C:
o Allows access for extensive lesions involving eustachian tube, clivus,
and parasellar region.
o Anterior extension of type B, in which the pterygoid process is drilled.

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o Radiotherapy:
ƒ Not modality of choice for treatment of surgically resectable
glomus tumors of temporal bone.
ƒ Indicated mainly for:
x Recurrences.
x Un-operable patients.
x Un-resectable lesions.

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Temporal Bone Trauma:

- Epidemiology:
o Associated with severe traumatic forces.
o Most commonly due to motor vehicle accidents.
o Occurs mainly in men (3:1).
o Mainly during 2nd to 4th decades of life.
o Most temporal bone fractures are Unilateral.
o Bilateral TB fractures in 20% of cases.

- Pathophysiology:
o Result from either posterior or lateral blows to the head.
o Takes the path of least resistance along the structurally
weakened points.
ƒ Fractures resulting from lateral (temporal) blows:
x Involve squamous and tympanic portions of TB.
x Starting-point:
o Originate through cortical areas of weakness
(EAC, mastoid air cells).
x Course:
o Propagate medially to pass through the
middle ear.
o Parallel to the long axis of the petrous bone
(longitudinal).
o Deflected anteriorly by otic capsule to reach
foramen lacerum.
o Inner ear and fallopian canal are spared.
x Ending-point:
o Most fractures terminate in floor of MCF or in
sphenoid bone.
o One third extend across midline to join a
contralateral fracture.
o Minority extend anteriorly to exit skull
through:
ƒ Anterior cranial fossa floor laterally.
ƒ Midline through the cribriform plate.

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ƒ Fractures resulting from posterior (occipital) blows:
x Involve mastoid and petrous portions of TB.
x Starting-point:
o Cortical origin of the fracture is generally in
the occipital bone.
x Course:
o Extends to foramen magnum and disrupts
the foramen magnum ring.
o Propagate anteriorly across petrous bone.
o At right angles to the long axis of petrous
bone (transvers).
o May pass lateral to, through or medial to the
otic capsule:
ƒ Most common path is directly through
otic capsule, disrupting inner ear.
ƒ Rarely, the fracture spares otic
capsule by passing medial to it, which
puts CN-VII and VIII at risk as the
fracture traverse the IAC.
ƒ Also rare, the fracture spares otic
capsule by passing lateral to it
through the middle ear.
x Ending-point:
o Terminates in floor of MCF.

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Traditional Classification of TB Fractures:
- Based on their anatomic relationship to the long axis of petrous bone.
- Divided into:
1. Longitudinal Fractures (80%)
2. Transverse Fractures (20%)
- Disadvantages:
o Most fractures are mixed type and follow mixed planes.
o Does not predict neur-otologic complications.
o Does not help with selecting surgical approach when necessary.

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New Classification of TB Fractures:
- Based on their involvement to the otic capsule.
- Divided into:
1. Otic Capsule Sparing Fractures (95%)
2. Otic Capsule Disrupting Fractures (5%)
- Advantages:
o Superior prediction of neur-otologic complications.
o Helps with selecting surgical approach when necessary.

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- Evaluation of Temporal bone fracture:
- Frequently associated with other life-threatening injuries.
- Initial evaluation must follow ATLS/ACLS guidelines.
x Focused History and Physical Examination:
o Cause:
ƒ Blunt vs. Penetrating.
ƒ Lateral vs Occipital.
o Assess Facial nerve:
ƒ Partial vs. Complete.
ƒ Immediate vs. Delayed
o Hearing loss:
ƒ Tuning forks if stable.
o Dizziness:
ƒ Nystagmus.
ƒ Peripheral or central.
ƒ BPPV most common in trauma.
ƒ Fistula test is not performed in presence of CSF leak.
ƒ Incidence of vertigo does not correlate with severity of
trauma
ƒ Most posttraumatic vertigo resolves spontaneously
o Presence of other neurological deficits.
o Presence of cranial nerve palsies.
o Otoscope examination:
ƒ Auricle or EAC lacerations
ƒ TM perforation.
ƒ CSF otorrhea.
ƒ Hemotympanum.
o Battle’s sign:
ƒ Ecchymosis over Mastoid process.
ƒ Indicates fracture of middle cranial fossa.

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x High-Resolution CT of Temporal Bone:
o Imaging of choice for temporal bone fractures.
o Fractures are best seen on axial imaging of thin cuts HRCT.
o Evaluates:
ƒ Site and type of the fracture.
ƒ Facial nerve involvement.
ƒ Otic capsule involvement.
o Trauma patients usually underwent CT Brain to assess for
intracranial hemorrhage.
o Indications of requesting HRCT of TB:
1. Facial paralysis
2. CSF fistula
3. Disruption of superior wall of EAC or scutum.
4. Suspected vascular injury.
5. Before any surgical intervention to manage otologic
complication.
o Indications of requesting CT Angiography:
1. Neurologic deficits.
2. Displaced fracture through carotid canal.

x Audiogram:
o Indications:
1. After 4-8 weeks of injury to allow for spontaneous
resolution of HL.
2. Prior to any surgical intervention.

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Complications of TB fractures and their Management:

1. External Ear Injures:

- Auricle:
o Lacerations are closed after cleaning & debridement.
o Drain hematomas.
o Pressure bolsters are sutured in place to close dead space.
- EAC:
o Better examined with microscope after stabilization.
o Examined aseptically (gloves & clean instruments).
o Inspected for:
ƒ Lacerations
ƒ Blood/CSF otorrhea
ƒ Brain herniation.
o EAC debridement with suction (irrigation is contraindicated).
o Packing should not be inserted unless required to control EAC
bleeding:
ƒ If profuse bleeding, control should be done at operating
room or angiography suite.
o Severely traumatized EAC:
ƒ Needs close follow-up with meticulous debridement to
prevent EAC stenosis and external canal cholesteatoma
formation.
ƒ If progressive stenosis is started, stenting with wicks or
merocell sponges serially for 3-6 months.
ƒ Canalplasty is done if complete EAC stenosis.
- TM:
o More common with longitudinal fractures.
o Small traumatic perforations generally heal spontaneously.
o Tympanoplasty for persistent perforations.

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2. Hearing Loss:
- Conductive HL:
o More common with otic-sparing fractures.
o Causes:
ƒ TM perforation.
ƒ Blood or CSF in middle ear.
ƒ Ossicular chain disruption (20%):
x Incudostapedial subluxation (80%)
x Incus dislocation (55%)
x Stapes crura fracture (30%)
x Ossicular fixation in epitympanum (25%)
o Treatment:
ƒ 80% of CHL resolve without intervention.
ƒ Residual CHL following resolution of hemotympanum and
healing of TM, suggests ossicular discontinuity.
ƒ Exploration and Ossiculoplasty:
x Indication:
- CHL >30 dB that persists for >2 months in
the absence of fluid or blood.
x Contraindications:
- Active infection.
- Only hearing ear.
- Mixed HL:
ƒ If BC threshold > 30 dB worse than
the contralateral ear.
ƒ Even with excellent closure of ABG,
ossiculoplasty will provide minimal
subjective improvement.
ƒ Patient would still require HA in the
surgical ear.
ƒ Ossiculoplasty in this condition can be
done only to enhance the HA post-op.
x Outcome:
- Superior results compared to CSOM patients.
- Closure of ABG to 10 dB in 80% of patients.
- Complete closure of ABG in 45% of patients.
- SNHL:
o More common with otic-capsule disrupting fractures.
o Result in severe to profound SNHL.
o Mechanism:
ƒ Disruption of membranous labyrinth.
ƒ Injury to CN-VIII.
ƒ Interruption of cochlear blood supply.
ƒ Hemorrhage into cochlea.
ƒ Perilymphatic fistulae.
o Outcome:
ƒ Patients with moderate-severe SNHL have some recovery.
ƒ Extremely poor prognosis for profound deafness.

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3. Facial Nerve Injury:
- Pathophysiology:
o Injury of facial nerve in TB fractures can result from:
ƒ Compression from bone fragments.
ƒ Intra-neural hematomas
ƒ Entrapment from compression and loss of continuity.
- Risk of FN paralysis:
o Up to 15% in otic-capsule sparing fractures.
o Up to 50% in otic-capsule disrupting fractures.
ƒ Due to perpendicular path of fracture with respect to
Facial nerve.
- Sites of injury:
o Most common site of facial nerve injury in temporal bone is in
peri-geniculate region (distal labyrinthine segment and
geniculate ganglion), due to:
ƒ Small size and lack of fibrous supporting tissue.
ƒ Traction between GSPN and geniculate ganglion.
ƒ Watershed areas of vascularization.
- Types of onset:
o Immediate-onset (30%):
ƒ Evaluated in ER upon admission and before administration
of muscle relaxants.
ƒ Unknown-onset:
x Occurs when the patient is intubated before
examination of facial function.
x Painful stimuli will elicit grimace.
x Should be considered and treated as immediate-
onset facial paralysis.
ƒ Associated with poor prognosis.
o Delayed-onset (70%):
ƒ Initial normal facial motion followed by deterioration.
ƒ Latency of facial palsy onset ranges from 1-16 days.
ƒ Secondary to post-traumatic edema and ischemia.
ƒ Associated with complete recovery (95%).
ƒ Not an indication for surgical exploration and
decompression of facial nerve.

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- Electro-diagnostic Tests:
o Indication:
ƒ Complete immediate-onset facial nerve paralysis.
x Highest risk for crushed, partially severed and
transected nerves which requires surgical
decompression.
o Tests:
ƒ ElectroNeuronography (ENoG):
x Most accurate electrodiagnostic test for prognostic
information.
x Useful only from 3-21 days after onset of injury.
x Required to determine timing and necessity of
surgical intervention.
x Interpretation:
o ≥ 90% degeneration within indicates 50%
chance of poor recovery.
o < 90% degeneration indicates excellent
recovery.

ƒ ElectroMyography (EMG):
x Useful only after 14 days after onset of injury.
x Interpretation:
o Voluntary action potentials:
ƒ Indicates at least partial continuity of
nerve.
ƒ Very high probability of good
recovery.
o Fibrillation potentials:
ƒ Confirm the presence of degenerating
motor units.
o Poly-phasic potentials:
ƒ Indicates re-innervation.
ƒ May be seen as early as 4-6 weeks
after the onset of paralysis.
ƒ Precedes clinical recovery and predicts
a fair to good recovery.

- Prognosis of Facial nerve paralysis:

o Most important predictive factor for recovery is onset of
paralysis:
ƒ Immediate-onset is associated with poor prognosis.
ƒ Delayed-onset is associated with full recovery.
o Poorer prognosis for recovery is associated with:
1. Immediate onset.
2. Complete paralysis.
3. Penetrating mechanism.
4. Associated infection.

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- Management of Facial Nerve Paralysis in TB Fractures:
o Conservative:
ƒ 2 weeks course of steroids.
ƒ 60% of patients recover spontaneously within 1 month.
ƒ 90% of patients recover spontaneously within 3 month.
ƒ Indications:
1. Delayed-onset:
o Any degree of facial nerve paralysis.
2. Immediate-onset:
o Incomplete facial nerve paralysis.
o Complete facial nerve paralysis with ENoG of
< 90% degeneration within 14 days.

o Surgical Decompression:
ƒ Most effective if performed ≤ 14 days of onset.
ƒ Indications:
1. Immediate-onset:
o Complete facial nerve paralysis with ENoG of
≥ 90% degeneration within 14 days.
ƒ Approaches:
x Hearing preservation approach (-ve SNHL):
o Combined trans-mastoid/middle cranial fossa
approach.
o Trans-mastoid/supra-labyrinthine approach.
x Non hearing preservation approach (+ve SNHL):
o Trans-labyrinthine total facial nerve
decompression.
ƒ General principles:
x Nerve is fully exposed.
x Identify all injured segments.
x Remove any compression from fracture fragments.
x Nerve sheath incised and any hematomas must be
evacuated.
x If complete transection, a direct end-to-end
anastomosis should be performed
ƒ Nerve endings should be prepared by
sharply cutting at 90 degree angle and
re-approximating under no tension
with two to three 9.0 nylon sutures
through the epineurium.
ƒ When a direct end-to-end anastomosis
creates tension, or when segments of
the nerve are missing or severely
damaged, inter-positional grafts from
greater auricular or sural nerve should
be used.

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4. CSF Leak:
o Occurs in 20% of TB fractures.
o Otic capsule sparing fracture:
ƒ Site of CSF leak:
x Floor of middle cranial fossa (Tegmen tympani and
Tegmen mastoideum).
ƒ Drains into:
x Epitympanum, antrum, and mastoid air cells.
o Otic capsule disrupting fracture:
ƒ Site of CSF leak:
x Posterior cranial fossa.
ƒ Drains into:
x Middle ear.
o Pathophysiology:
ƒ Immediate-onset in majority of patients.
ƒ Otic capsule fractures does not heal fully and the CSF
fistula will continue to leak until fibrosis is formed to close
the subarachnoid space or middle ear or mastoid air cell
mucosa covers bony defect:
x This barrier is weak and it will be ruptured by
increased ICP (nose blowing or straining) and CSF
leak will continue.
ƒ Delayed-onset (> 1 week) in 30% of patients due to:
x Resolution of occluding hematoma.
x Separation of fibers in the dural herniation.
x Increased ICP.
o Presentation:
ƒ If reached the ET, CSF rhinorrhea.
ƒ If TM is perforated, CSF otorhea.
ƒ Increases with exertion or leaning forward.
o Diagnosis (Similar to CSF rhinorrhea protocol):
ƒ Beta-2 Transferrin:
x Detected with protein electrophoresis.
x Specific for CSF.
x Only small amount of CSF is required (0.05 mL).
ƒ Beta Trace protein:
x Synthesized in the meninges.
x 20-40 fold CSF concentration compared to serum.
x Less expensive and faster than β2–transferrin.
x Detection via nephelometric technique comparable
specificity and sensitivity to β2–transferrin.
x Recent studies showed 100% positive and negative
predictive values of CSF leakage.
ƒ High resolution CT:
x Shows bony defect in 70% of patients.
ƒ Intrathecal fluorescein:
x Successful for localizing fistulae when all other
methods have failed.

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o Management of CSF leak:
ƒ Conservative:
x Indication:
o CSF leak after acute trauma.
x Period:
o 7-10 days after trauma.
x Goal:
o Maintaining CSF pressure gradient below
healing tensile strength of the healing
barrier.
x Instructions:
o Bed rest.
o Head elevation.
o Avoid nose blowing, strenuous activity, and
constipation.
x Medications:
o Diuretic agents (mannitol, acetazolamide,
furosemide).
o Prophylactic antibiotics (controversial)
x Intervention:
o Lumbar drain if persistent leak.
x Prognosis:
o 60-90% of patients with CSF leak will
improve within one week.
x Complications:
o Meningitis:
ƒ 5% risk of meningitis in patients
active CSF leak of < 7 days.
ƒ 25% risk of meningitis in patients
active CSF leak of > 7 days.

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ƒ Surgical Closure:
x Indications:
o Failure of conservative management for 7-10
days after acute trauma.
x Goal:
o Closure of the non-healing CSF fistula.
o Avoid the increased risk of meningitis after
7-10 days of active leak.
x Approaches:
o Non-Hearing preservation approach
(+ve SNHL):
ƒ Blind sac procedure and fat
obliteration of mastoid and middle ear.
o Hearing preservation approach (-ve
SNHL):
ƒ Depends on:
x Location of fracture.
x Presence of brain herniation.
x Status of ossicular chain.
ƒ Lateral defect in the mastoid at MCF:
x Mastoidectomy.
x Temporalis fascia graft over the
fistula.
x Fat obliteration of mastoid
cavity.
ƒ Medial defect in Tegmen tympani with
brain herniation (> 1cm):
x Combined Trans-mastoid/MCF
approaches.
x Trans-mastoid approach used to
debride the herniated.
x MCF approach used for
reconstruction with temporalis
fascia is placed over floor of
MCF followed by bone graft
superiorly.
ƒ Medial defect in Tegmen tympani with
ossciuclar discontinuity and without
brain herniation (<1cm):
x Trans-mastoid approach alone.
x Cartilage graft followed by
Temporalis fascia.
x Fat obliteration of mastoid
cavity.

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5. Vertigo:
o Causes:
1. BPPV (Most common/ 30% of all head traumas)
2. Labyrinthine concussion
3. Disruptive injury to the labyrinth.
4. Disruptive injury to CV-VIII.
5. Traumatic perilymphatic fistula
6. Post-traumatic Ménière syndrome

6. Vascular injuries:
o Rare (1%).
o Intra-temporal carotid injury.
o Present with profuse bloody otorrhea.
o Suspected in patients with fracture of carotid canal on HRCT.
ƒ 60% sensitivity and 67% specificity.
o CT Angio if actively bleeding with declining neurological status
o OR for ligation or angiography for balloon occlusion

7. Cholestetoma:
o Late complication.
o Can grow for years without detection
o Mechanisms:
1. Epithelial entrapment in fracture line (Epitympanum)
2. In-growth of epithelium through unhealed fracture line
3. Traumatic implantation of TM skin in middle ear
4. Trapping of epithelium medial to EAC stenosis

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- Penetrating injury to Facial nerve:
o Most commonly due to gunshot wounds (GSW).
ƒ Handguns produce low-velocity injuries.
ƒ Rifles produce high-velocity ones.
o High-velocity wounds cause injury by crush, laceration and
cavitation.
o Cavitation may involve tissues away from bullet’s trajectory.
o Internal carotid artery injury due to stretching is common and
should be suspected.
o CN-VII injury occurs in 50% of GSWs to temporal bone.
ƒ More frequently involve labyrinthine or tympanic
segment.
ƒ Nerve may be transected, or secondarily injured by
kinetic injury from the bullet or from bony fragmentation
of the temporal bone.
ƒ Generally, outcome of facial function is much worse with
gunshot wounds to temporal bone than with temporal
bone fractures.
o EAC laceration, stenosis and cholesteatoma formation is
common.

- Pediatric Temporal Bone Fractures:

o Uncommon.
o Same etiologies seen in adults.
o Associated CNS trauma is common (40-75%).
o CN-VII paralysis is less common in children than adult (3-10%).
o Temporary CSF leak is common but resolves spontaneously.
o Management of pediatric TB fractures is similar to the adults.

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Facial Nerve Paralysis:

- Nerve Fiber Components:

Axon
1. Endo-neurium:
↓
o Surrounds each Nerve Fiber (Axons).
Myelin sheath
o Tightly adherent to Schwann cell layer.
↓
o Provides Endoneural tube for Regeneration.
Neurilemma
o Poorer prognosis for regeneration when disrupted.
↓
2. Peri-neurium:
Endoneurim
o Surrounds Fascicles (Group of Axons).
o Provides tensile strength.
o Maintains intrafunicular pressure.
Group of Axons
o Protects from infection.
↓
3. Epi-neurium:
Fascicles
o Nerve Sheath.
↓
o Outer layer.
Perineurim
o Surrounds group of Fascicles.
o Contains the Vasa Nervorum for nutrition.
Group of Fascicles
↓
Epineurim

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- Pathophysiology of Nerve injury:
- When an axon is injured, biochemical and histological changes occur in
cell body proximal and distal to site of injury.
- Severity of changes depend upon:
1. Distance from the injury to the cell body:
ƒ Proximal injuries are more severe than distal injuries.
2. Type of injury:
ƒ Crush injuries are more severe than clean transections.
3. Age of the patient:
ƒ Older individuals sustain more severe injury.
4. Nutritional and Metabolic status of the patient.

- Wallerian Degeneration and Regeneration:

- Process of degeneration of axons and Myelin sheaths following axonal
lesions.
- Begins immediately after injury but progresses slowly.
- Propagates distally from site of injury to motor end plate.
- Propagates proximally to the first adjacent node of Ranvier.
- Prior to degeneration, distal axon stumps tend to remain electrically
excitable up to 3-5 days after injury:
o Electrodiagnostic testing cannot distinguish between neurapraxic
and neurodegenerative injuries during this period.
- After injury:
o Æ Axonal membrane breaks apart.
o Æ Degradation of myelin sheath.
o Æ Infiltration by macrophages and Schwann cells to clear the
debris from the degeneration.
o Æ Axon's Neurolemma does not degenerate and remains as a
hollow tube.
o Æ Axon sprouts are send out of distal end of proximal part of
the nerve towards those tubes.
o Æ Grows into the tubes and advances 1 mm/day.
o Æ Reinnervation of target tissue.

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- Sunderland Classification of Nerve Injury:

1. First Degree (Neuropraxia):

o Intact Axons.
o Partial interruption of Axoplasmic flow due to compression.
o No morphological changes are seen.
o No Wallerian degeneration.
o Will conduct neural discharge if stimulated distal to the block.
o Recovery of function is complete.
o Seen in viral and inflammatory disorders.

2. Second Degree (Axonotmesis):

o Loss of Axons.
o Intact Endoneurial tubes.
o Interrupted Axoplasmic flow.
o Seen in viral and inflammatory disorders.
o Wallerian degeneration occurs.
o Axons regenerates through intact neural tubes @ 1 mm/day.
o Complete recovery anticipated.

3. Third Degree (Endoneurotmesis):

o Loss of Axons.
o Loss of Endoneurial tubes.
o Seen in viral and inflammatory disorders.
o Wallerian degeneration occurs.
o Regenerating axons:
ƒ Enter the wrong endoneurial tubes.
ƒ Fail to enter enduneurial tubes.
o Results in:
ƒ Synkinesis:
x Abnormal mass movement of muscles which do not
normally contract together.
ƒ Incomplete recovery.

4. Fourth Degree (Perineurotmesis):

o Partial Nerve Transection.
o Loss of Perineurium (in addition to above).
o Only Epineurium is intact.
o Seen in surgical or accidental trauma or in neoplasms.
o Scarring will impair regeneration of fibers.
o Greater risk for synkinesis and incomplete recovery.

5. Fifth Degree (Neurotmesis):

o Complete Nerve Transection.
o Loss of Epineurium (in addition to above).
o Seen in surgical or accidental trauma or in neoplasms.
o Risk of Neuroma from nerve sprouts outside of nerve sheath.
o Without surgical repair, No chance of regeneration and recovery.

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- Evaluation of Facial Nerve Paralysis:

- History:
- Character of Facial weakness:
o Onset (Sudden vs Delayed).
o Duration.
o Progression of paralysis (complete vs incomplete).
o Recurrent (Previous history of Facial nerve paralysis).
- Contributing Factors:
o Recent infection or illness.
o Trauma (birth trauma in neonates).
o Surgery (Otologic, Parotid, or Neurologic surgery).
o Recent tick bites or outdoor activity.
o History of syphilis, HIV, TB or Herpes.
o Toxin exposure (Lead).
o History of Otologic, Neurologic, Diabetic, or Vascular disorders.
- Associated Symptoms:
o Change in taste sensation.
o Drooling.
o Epiphora.
o Vision changes.
o Pain (Auricular, Postauricular, or Facial).
o Ear symptoms (hearing loss, aural fullness, otalgia, vertigo or
hyperacusis).
o Neurologic deficits.

- Physical Exam:
- Facial Nerve:
o Unilateral vs Bilateral weakness.
o Central vs Peripheral.
ƒ Forehead movement.
o Observe facial symmetry at rest and with movement.
o Hemifacial spasms.
o Facial tics at rest.
o Eye closure.
o Tear production.
o Corneal Reflex.
o Visual acuity.
o Bell's phenomenon:
ƒ Globe turns up and out
during attempts to close
eyes.
ƒ Indicates Peripheral
lesion.

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- House-Brackmann System of Grading Facial Nerve Paralysis:
o Grade I:
ƒ Normal.
o Grade II:
ƒ Symmetry at Rest.
ƒ No/minimal synkinesis.
ƒ Complete eye closure with Minimal effort.
o Grade III:
ƒ Symmetry at Rest.
ƒ Obvious synkinesis.
ƒ Complete eye closure with Maximum effort.
o Grade IV:
ƒ Symmetry at Rest.
ƒ Obvious synkinesis.
ƒ Incomplete eye closure.
o Grade V:
ƒ Asymmetry at Rest.
ƒ Obvious synkinesis.
ƒ Incomplete eye closure.
o Grade VI:
ƒ Total paralysis.

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- Other Head and Neck Assessment:
o Ear examination:
ƒ Evaluate for mass or fluid in Middle ear.
ƒ Presence of vesicles in EAC and concha.
ƒ Hitselberger sign:
x Hypesthesia of sensory division of Facial nerve at
superior posterior concha.
o Neck examination:
ƒ Parotid masses.
ƒ Lymph nodes.
o Neurological examination:
ƒ Other cranial nerve involvement.
ƒ Other lateralizing signs:
x Hemiparesthesias.
x Hemiparalysis.
x Aphasia.

Localization of Facial Nerve Lesions:

1. Central Facial Paralysis (UMNL):
- Paralysis of lower half of the face on the contralateral side only.
- Forehead is preserved:
o Receives bilateral innervation.
- Involuntary emotional movements and tone
are preserved:
o Receives fibers from Thalamus.
- Caused by:
1. CVA.
2. Tumour
3. Abscess.

2. Peripheral Facial Paralysis (LMNL):

- Paralysis of all muscles of the face on the
ipsilateral side.
- Forehead is involved.
- Lesion at level of Motor Nucleus:
o Associated paralysis of CN-VI.
- Lesion at CPA:
o Vestibular and Auditory defects.
o Associated paralysis of CN-V, CN-IX, CN-X and CN-XI.
- Lesion in Fallopian canal:
o Localized by Topodiagnostic tests.
- Lesion outside Temporal bone:
o Affects only motor functions of Facial nerve.

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Topo-gnostic Tests for Intra-Temporal FN Lesions:

- Based on principle that lesions distal to the site of a particular branch

of the facial nerve will spare the function of that branch.
- Rarely used nowadays.
- Not found to be of much use clinically for determining the site of the
lesion in facial paralysis or for predicting the outcome.

1. Schirmer's Test:
o Compares lacrimation of the two sides.
o Strip of filter paper is hooked in lower fornix
of each eye.
o Amount of wetting of strip is measured.
o After 5 minutes, Length of strip that is moist
is compared to the normal side.
o Predict patients at risk for exposure keratitis.
o Abnormal Results (Either):
ƒ Value of <50% compared to normal side.
ƒ Total lacrimation less than 25 mm
o Indicates:
ƒ Lesions at or proximal to Afferent limb:
x Ophthalmic (V1) of Trigeminal nerve.
ƒ Lesions at or proximal to Efferent limb:
x Greater superficial petrosal nerve (branching at
geniculate ganglion).

2. Stapedial Reflex:
o Most objective and reproducible test.
o Useful in determining facial nerve prognosis.
o Tested by tympanometry.
o Abnormal Result (Either):
ƒ Absent stapedial reflex.
ƒ Amplitude of <50% compared to normal side.
o Indicates:
ƒ Hearing loss:
x Any degree of CHL.
x Cochlear SNHL > 60 dB
x Any degree of Retro-cochlear SNHL
ƒ Lesions at or proximal to the Efferent limb:
x Nerve to stapedius (branching after second genu in
the vertical segment).

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3. Taste Test:
o Measured by a drop of salt or sugar solution placed on one side
of protruded tongue.
o Abnormal Result:
ƒ Impairment of taste (dysgeusia/ageusia).
o Indicates:
ƒ Lesions at or proximal to lingual nerve.
ƒ Lesions at or proximal to chorda tympani:
x Branching anywhere in the vertical segment.
o More reliable indicator of interruption of Chorda tympani nerve
involves microscopic detection of Absence of taste papillae on
the middle 1/3 of involved side of Tongue:
ƒ Disappear within 10 days post injury.

4. Submandibular Salivary Flow and PH Test:

o Polythene tubes are passed into both Wharton's ducts.
o Measurement of output after five minutes.
o Abnormal Result:
ƒ Flow rate ≤ 25% compared to normal side.
o Indicates:
ƒ Lesions at or proximal to lingual nerve.
ƒ Lesions at or proximal to chorda tympani:
x Branching anywhere in the vertical segment.
o Salivary pH may be examined as an indirect measure of flow:
ƒ As Flow rate decreases, pH decreases.
ƒ pH of ≤ 6.1 may predict loss of function of Chorda
tympani.

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- Supragengulate lesions cause:
1. Decreased lacrimation.
2. Loss of Stapedial reflex.
3. Loss of Taste.
4. Decreased salivation
5. Loss of Motor function.

- Suprastapedial lesions cause:

1. Preserved lacrimation.
2. Loss of Stapedial reflex.
3. Loss of Taste.
4. Decreased salivation
5. Loss of Motor function.

- Infrastapedial lesions cause:

1. Preserved lacrimation.
2. Preserved Stapedial reflex.
3. Loss of Taste.
4. Decreased salivation
5. Loss of Motor function.

- Infrachordal lesions cause:

1. Preserved lacrimation.
2. Preserved Stapedial reflex.
3. Preserved Taste.
4. Preserved salivation
5. Loss of Motor function.

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Ancillary Studies for Evaluation of Facial Nerve paralysis:

x Audiogram:
- Indicated for all Intra-temporal injuries.
- Preoperative baseline hearing.

x Topognostic Tests:
- Not useful.
- Replaced with Electrophysiological testing.

x Blood work:
- Indicated for suspected patients with inflammatory diseases.
o CBC
o Treponemal Studies:
ƒ Lyme titers and VDRL/FTA-ABS
o ACE level:
ƒ Active sarcoidosis

x Imaging:
- MRI with gad is the most sensitive imaging for evaluation of entire
course of facial nerve.
- CT with contrast can be done for patients contraindicated for MRI.
- Indications of imaging in patients with facial paralysis:
1. History of recurrent ipsilateral paralysis.
2. Bilateral facial paralysis.
3. Gradually developing facial nerve paralysis.
4. No evidence of recovery after 3 month from onset.
5. History of Trauma (HRCT Temporal bone).
6. Concurrent otologic findings (cholesteatoma).
7. Associated Neurological symptoms.
8. Other cranial nerve involvements.
9. Suspected CPA lesions.

x Electrophysiological Tests:
- These tests are complimentary (no single best test).
- Differentiate between neurapraxia and nerve degeneration.
- Indication:
o Patients with complete facial nerve paralysis:
ƒ Determine prognosis for return of facial function.
ƒ Choosing candidates for surgical intervention:
x Decompression surgery (ENoG).
x Reanimation surgery (EMG).

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- No value of electrophysiological tests in:
o Before 3 days of the onset of complete facial nerve
paralysis:
ƒ Nerve degeneration didn’t reach site of stimulation.
ƒ Facial nerve will remain electrically excitable regardless
the type of injury.
ƒ Results will be misleading.
o After 21 days of the onset of complete facial nerve
paralysis:
ƒ Complete nerve degeneration has occurred.
ƒ After loss of excitability, tests that require electrical
stimulation (NET,MST and ENoG) are no longer useful.
ƒ EMG is the only test that give prognostically useful
information during this period.
o Patients with incomplete facial nerve paralysis:
ƒ Facial movements indicates neurapraxic intact nerve.
ƒ Good recovery is anticipated.

Types of Electrophysiological Tests:

1. Nerve Excitability Test (NET):

- Rarely used today due to its major drawbacks.
- Method:
o Facial nerve is stimulated with over stylomastoid foramen.
o Return electrode is taped to the forearm.
o Electrical pulses are delivered at steadily increasing current
levels until a facial twitch is noted.
o Lowest current necessary to produce facial twitch (Excitation
threshold) on normal side is compared with paralyzed side.
o Difference in thresholds between two sides is calculated.
- Interpretation:
o Conduction block (Neuropraxia/Type I):
ƒ No difference in excitation threshold between two sides.
ƒ No degeneration occurs.
ƒ Good prognosis for complete recovery.
o Degenerative injuries (Type II-V):
ƒ Difference in excitation threshold of > 3.5 mA indicates
significant degeneration.
ƒ Poor prognosis for return of facial function.
- Advantages:
o Low cost, readily available equipment, and ease of performance.
o Used for evaluation of acute facial paralysis (while in the
degenerative phase).
- Disadvantages:
o Subjective test with reliance entirely on a visual end point.
o Few intact axons can give visible response leading to wrong
prediction of good prognosis, while most fibers are degenerated.
o Used for unilateral paralysis (comparison with normal side).

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2. Maximum Stimulation Test (MST):
- Modified version of NET.
- Method:
o Facial nerve is stimulated with electrode over stylomastoid
foramen.
o Return electrode is taped to the forearm.
o Electrical pulses are delivered at steadily increasing current
levels until a facial twitch is noted.
o Instead of measuring excitation threshold, the current level
which gives maximum facial movement is measured (Maximum
stimulation level) in the normal side.
o This maximum stimulation level is then used to stimulate the
affected side.
o Degree of facial contraction in the affected side is subjectively
(visually) assessed as either equal, decreased or absent.
- Interpretation:
o Good prognosis:
ƒ Equal or slightly decreased response on involved side
compared to the normal side.
ƒ Favorable for complete recovery.
o Poor prognosis:
ƒ Absent or markedly decreased response on involved side.
ƒ Advanced degeneration.
ƒ Incomplete recovery.
- Advantages:
o Low cost, readily available equipment, and ease of performance.
o Used for evaluation of acute facial paralysis (while in the
degenerative phase).
o MST is considered superior to NET.
ƒ Stimulating all intact axons.
ƒ MST response becomes abnormal earlier than NET
response.
ƒ More reliably guide prognosis and treatment than NET.
- Disadvantages:
o Subjective test with reliance entirely on a visual end point.
o Used for unilateral paralysis (needs comparison with normal
side).

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3. ElectroNeuronography (ENoG):
- Also called Evoked Electromyography (EEMG).
- Method:
o Facial nerve is stimulated with electrode over stylomastoid
foramen.
o Muscular response is recorded using bipolar electrodes placed
near nasolabial groove.
o Measures the amplitude of evoked Compound Muscle Action
Potential (CMAP):
ƒ Considered proportional to number of intact axons.
o The amplitude of evoked CMAP in the involved side is compared
to the normal side.
- Interpretation:
o Good prognosis:
ƒ Degeneration of < 90% of axons within 14 days of onset.
ƒ Amplitude of evoked CMAP on involved side is reduced to
more than 10% of normal side.
ƒ Expected spontaneous rate of recovery of 80-100%.
o Poor prognosis:
ƒ Degeneration of ≥ 90% of axons within 14 days of onset.
ƒ Amplitude of evoked CMAP on involved side is reduced to
10% or less of normal side.
ƒ Faster rate of degeneration occurring in less than 14 days
has a poorer prognosis.
ƒ Poor prognosis for spontaneous recovery without surgical
decompression.
- Advantages:
o Used for evaluation of acute facial paralysis (while in the
degenerative phase).
o Most accurate prognostic test for complete facial paralyis:
ƒ Objective, qualitative measurement of nerve
degeneration.
ƒ Used to calculate percentage of intact axons.
ƒ Helps to choose candidates for surgical decompression.
- Disadvantages:
o Discomfort and cost.
o Repeated every other day during the first 2-3 weeks following
nerve injury to detect accelerating ongoing degeneration.
o Test-retest variability due to positioning of the electrodes and
excitation of the muscles of mastication (V).
o Used for unilateral paralysis (needs comparison with normal
side).

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4. ElectroMyography (EMG):
- Evaluates motor activity of facial muscles and presence of functional
motor units.
- Method:
o Direct insertion of needle electrodes into facial muscles
(orbicularis oculi and orbicularis oris muscles).
o Measures spontaneous and voluntary muscle potentials.
o Normally:
ƒ Electrical silence in normal muscle at resting state.
ƒ Diphasic or Triphasic muscle action potentials are
generated by voluntary activity.
- Interpretation:
o Electrical silence:
ƒ Indicates either:
x Normal muscle in a resting state.
x Acute facial paralysis in the early stages (before
complete nerve degeneration takes place).
x Severe muscle wasting and atrophy in late stages.
o Voluntary action potentials:
ƒ Indicates at least partial continuity of nerve.
ƒ Confirms the integrity of intact axons.
ƒ Very high probability of good recovery.
o Fibrillation potentials:
ƒ Spontaneous involuntary action potentials.
ƒ Electrical sign not clinical sign (not visible).
ƒ Appears after complete nerve degeneration and loss of
excitability (after 14-21 days).
ƒ Impaired reinnervation yield fibrillation potentials as long
as postsynaptic membranes remain electrically active.
ƒ With persistent denervation, EMG recordings are silent
and insertional activity are lost (18-24 months).
o Polyphasic potentials:
ƒ Indicates re-innervation.
ƒ After nerve injury, nerve fibers can regrow down the old
nerve sheath and can sprout to supply denervated
muscles.
ƒ New sprouts are de-synchronous.
ƒ Muscle potential is polyphasic (> 5 phases).
ƒ Observed during voluntary muscle contraction.
ƒ Appears 4-6 weeks after the onset of paralysis.
ƒ Precedes clinical recovery and provide the earliest
evidence of recovery.
ƒ Predicts a fair to good recovery.

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Riyadh et al. Notes
599
- Advantages:
o Used as complementary for ENoG when ≥ 90% degeneration
has occurred and surgery is being considered:
ƒ If EMG shows voluntarily active facial motor units, the
prognosis for a good spontaneous recovery is good.
o Used for evaluation of chronic facial paralysis (after complete
nerve degeneration has occurred).
o Useful in planning re-animation surgeries:
ƒ Polyphasic potentials after 1 year of injury:
x Reinnervation is already taking place.
x No need for reanimation procedure.
ƒ Fibrillation potentials after 1 year of injury:
x Intact motor end plates.
x No evidence of reinnervation.
x Need for nerve substitution.
ƒ Electrical silence after 1 year of injury:
x Atrophy of motor end plates.
x Need for muscle transfer procedures rather than
nerve substitution.
- Disadvantages:
o Discomfort and cost.
o Limited value in early evaluation of acute facial paralysis (before
complete nerve degeneration takes place).
o Can’t assess degree of nerve degeneration.

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Causes of Facial Nerve Paralysis:
- Central or Peripheral.
- Peripheral lesions are more common.
o Bell’s palsy is the most common cause (50%) of all cases.
o Trauma is the second most common cause (20%) of all cases.

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Bell’s Palsy:

- Idiopathic facial paralysis of acute onset and limited duration.

- Most common cause of facial nerve paralysis (70%).

- Epidemiology:
o Both sexes are affected with equal frequency.
o Any age group may be affected.
ƒ Greatest incidence from age 15 to 45.
o History of previous paralysis in 10% of patients.
o Family history of Bell palsy in 10% of patients.

- Pathophysiology:
o Viral Polyneuropathy:
ƒ Most widely accepted theory.
ƒ Resulted from reactivation of latent herpes simplex virus
type 1 (HSV-1) infection.
ƒ HSV-1 DNA was isolated in the geniculate ganglion using
the PCR in 80% of patients with Bell’s palsy who
underwent decompression surgery.
ƒ Causing cranial nerve polyneuritis:
x Facial paralysis is the most obvious finding.
o Facial nerve differs from other cranial nerves
by its long bony fallopian canal.
o HSV-1 infection results in facial nerve edema
within the narrowest part of the fallopian
canal (meatal foramen/junction of meatal
segment and labyrinthine segment/0.68
mm) resulting in impaired axoplasmic flow.
x Other cranial nerves involvement are
relatively minor and transient.
o Found in more than 50% of patients with
Bell’s palsy.

o Ischemic Neuropathy:
ƒ Vasospasm induced by cold or emotional stress.
ƒ Ischemia causes increased capillary permeability leading
to exudation of fluid, edema and compression of
microcirculation of the nerve.

o Hereditary:
ƒ Fallopian canal is narrow because of hereditary
predisposition.
ƒ Facial nerve is susceptible to early compression with the
slightest edema.
ƒ Positive family history is present in 10% of patients.

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- Histopathology:
o Most recent studies demonstrated inflammatory infiltrates
throughout the course of the facial nerve.
o Vascular thrombosis is generally not observed.
o Intra-neural hemorrhage is seen occasionally.

- Diagnosis:
o Bell’s palsy was considered to be a diagnosis of exclusion after
ruling out all other possible causes.
o Recent criteria to diagnose Bell’s palsy:
1. Unilateral weakness of all facial muscles.
2. Sudden onset.
3. No evidence of otologic disease.
4. No evidence of CNS disease.
5. No evidence of CPA lesion.

- Risk factors for developing Bell's palsy:

o Pregnancy Pre-eclampsia: Facial paralysis during
pregnancy can occur in cases of preeclampsia.
o Obesity
o Hypertension
o Diabetes
o Upper respiratory illness

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- Clinical Features:
o Unilateral weakness of all facial muscles:
ƒ Involving the forehead muscles (LMNL).
ƒ Left and right sides of the face are equally involved.
ƒ Bilateral involvement is rare (0.3%).
ƒ 70% of patients have complete paralysis.
ƒ 30% of patients have incomplete paralysis.
o Sudden onset:
ƒ Progresses to its maximum severity within 72 hours of
onset.
ƒ Delayed progression over weeks or months is not Bell
palsy.
o Dysgeusia:
ƒ Loss of taste.
ƒ Due to involvement of chorda tympani.
o Hyperacusis:
ƒ Noise intolerance due to stapedial paralysis.

- Investigations:
o Routine labs:
ƒ Not indicated in patients with new onset Bell’s palsy.
o Imaging:
ƒ Not indicated in patients with new onset Bell’s palsy.
ƒ MRI with Gad of entire course of facial nerve is the
imaging test of choice.
ƒ Indications of imaging in Bell’s palsy:
1. Recurrent ipsilateral facial paralysis:
o 20% risk of having tumor.
2. Bilateral facial paralysis.
3. Paralysis of isolated branches of the facial nerve.
4. Other cranial nerve involvements.
5. No sign of recovery after 3 months.

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o Electrodiagnostic tests:
ƒ Indication:
x Complete facial paralysis.
o Should not performed in patients with
incomplete facial paralysis due to the high
chance of recovery.
ƒ Aim:
x Identify patients with poor prognosis.
x Identify candidates for surgical decompression.
ƒ Period:
x Done between 3-21 days of onset.
ƒ Approach:
x ENoG is done first:
o If degeneration of < 90% of axons:
ƒ Indicates good prognosis.
ƒ Most patients recover normal or near-
normal facial movement.
o If degeneration of ≥ 90% of axons:
ƒ Indicates poor prognosis.
ƒ Most patients do not recover.
ƒ EMG is then done:
x If voluntary muscle potential
was recorded:
o Indicates intact axons.
o Possible good recovery.
x If no voluntary muscle potential
was recorded:
o Indicates damaged
axons.
o Poor recovery.
o May consider surgical
decompression.

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607

- Prognosis for Bell's palsy:

o Most patients will recover spontaneously without treatment.
o The sooner the recovery, the less likely are the chances that
sequelae will develop:
ƒ 85% of patients will show some recovery within 3 weeks
and the ultimate outcome is usually satisfactory.
ƒ If recovery begins 2-4 months from onset, high risk of
permanent sequelae.
o Complete recovery is typically achieved by 2 months:
ƒ Patients with complete paralysis will have complete
recovery after 3-5 months.
o Risk factors associated with a poor outcome:
1. Complete paralysis:
x Single most important prognostic factor.
2. Age greater than 60 years.
3. Long interval time of before onset of recovery.
4. Pain in the posterior auricular area.
5. Hyperacusis.
6. Decreased tearing.
7. Diabetes mellitus.
8. Hypertension.
o Overall rate of spontaneous complete recovery within 6 months:
ƒ 95% of patients with incomplete paralysis.
ƒ 70% of patients with complete paralysis.
o Patients on steroid therapy has 20-30% better chance of
complete recovery compared to untreated patients.
o No difference in prognosis between primary and subsequent
attacks of facial paralysis.
o Recovery in bilateral Bell palsy is similar to unilateral palsy.

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608

Management of Bell's palsy:

- Medical Management:

1. Oral Prednisone:
ƒ Dose:
x 1 mg/kg/day for 5 days, then tapered over 5 days,
for total of 10 days.
x Used within 72 hours from onset of symptoms.
ƒ Strong recommendation:
x Decrease recovery time.
x Improving facial nerve functional recovery.
x Prevents or lessens nerve degeneration.
x Decreases synkinesis.
ƒ Oral steroids may be considered in pediatric patients.
2. Oral Pantoprazole:
ƒ 40 mg daily.
ƒ Decrease risk of peptic ulcer with oral prednisone.
3. Oral Anti-viral:
ƒ Dose:
x Acyclovir 400 mg PO 5 times daily for 10 days, or
x Valacyclovir 500 mg PO BID for 5 days.
x Used within 72 hours from onset of symptoms.
ƒ Optional:
x Antiviral therapy combined with oral steroids was
not statistically significantly superior to oral
steroids alone.
x Small benefit cannot be completely excluded.
x Antiviral agents alone provide no benefit.
x Should not be given as monotherapy in new-onset
disease (Strong recommendation against).
4. Eye Care:
ƒ Ophthalmic evaluation to rule out exposure keratitis.
ƒ Strong recommendation:
x Use of sunglasses.
x Frequent use of lubricating ophthalmic drops and
ointments.
x Use of a moisture chamber.
x Eye patching or taping during sleep.

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Riyadh et al. Notes
609

- Surgical Management:

o Surgical Decompression:
ƒ Controversial.
ƒ No strong data supporting surgical decompression.
ƒ Can be considered for patients high risk of poor recovery:
x Patients with complete facial paralysis and ENoG is
showing ≥ 90% axonal degeneration and EMG is
showing absent voluntary muscle potential.
ƒ Period:
x Surgery must be performed within 14 days of
symptom onset for optimal effectiveness.
ƒ Aim:
x Decompression of the labyrinthine segment.
x Decompression of mastoid and tympanic segments
no effect on recovery of facial function.
ƒ Approach:
x Middle cranial fossa approach.
x Trans-mastoid approach is not used as the
segment involved (proximal labyrinthine segment)
is inaccessible through the mastoid.
ƒ Results:
x 90% of patients achieved HB outcome of I/II
postoperatively compared with only 40% of
patients who underwent medical management with
steroid-only.

- No sufficient evidence to recommend for Acupuncture or

Physical therapy for management of Bell’s palsy.

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610

Facial Nerve Trauma:

- Second most common cause of facial paralysis (20% of all cases).

- Types:
o Temporal bone fractures:
ƒ See Temporal bone trauma for more details.
o Penetrating facial nerve injuries:
ƒ Intra-temporal part:
x See Temporal bone trauma for more details.
ƒ Extra-temporal part:
x For complete paralysis:
o Surgical exploration and repair with an end-
to-end anastomosis should be undertaken as
Immediate facial paralysis soon as the patient is medically stable.
after penetrating trauma o Ideally repaired within three days (distal
should be considered a nerve branches may be stimulated up to 3 days
transection and the patient
after injury).
should be surgically explored
o If the wound is contaminated or there is
when the wound is lateral to
the lateral canthus significant tissue loss may consider
identifying distal and proximal ends of the
facial nerve with plans for a second stage
procedure within 3–4 weeks.
o Electrical stimulation can still be used to help
locate the distal branches.
x If the penetrating injury is medial to lateral
canthus of the eye:
o Recover spontaneously.
o No need for exploration.
o Nerve endings are small and a rich
anastomotic network exists in this area.

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612

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Riyadh et al. Notes
613
o Iatrogenic facial nerve injuries:
ƒ Occurs in < 1% during middle ear or mastoid surgeries.
ƒ Most common sites of facial nerve injury during ear
surgery (most common sites of facial nerve dehiscence):
1. Tympanic segment (80%):
o Superior or adjacent to oval window.
2. Vertical segment (1%).
ƒ Facial nerve injury may also occur with salivary gland
surgery, neck dissections, rhytidoplasties, and branchial
cleft excisions

ƒ Management of iatrogenic injury during ear surgery:

x Confirmed intraoperative injury:
x Injury to fallopian canal with exposure of
epineurium with minor abrasion of nerve sheath:
o No consequence.
x Transection of < 30-40% of nerve diameter:
o Expert colleague must be consulted.
o Fallopian canal should be decompressed 3-4
mm proximal and distal to injured segment
and epineurium should be incised.
o Intra-op and post-op steroids.
x Transection of > 40-50% of nerve diameter:
o Expert colleague must be consulted.
o Injured segment is resected and repaired
with primary anastomosis or cable grafting.

x Immediate postoperative facial weakness:

x Tight dressings and packing should be released
immediately to relieve the pressure over facial
nerve.
x Wait for local anesthetic to wear off (2–3 hours)
then re-evaluate.

x If still paralyzed:
o Surgeon is confident about Facial nerve
preservation intra-op:
ƒ Expert colleague must be consulted.
ƒ Corticosteroids.
ƒ Follow progression with serial
electrodiagnostic testing.
ƒ If advanced degeneration (>90%) is
evident:
x Surgical exploration and
Decompression.

1520
Riyadh et al. Notes
614
o Surgeon is Not confident about Facial nerve
preservation intra-op:
ƒ Surgical exploration and repair as
soon as possible by an expert
surgeon.

x Delayed postoperative facial weakness:

x More common than immediate-onset paralysis.
x Occurs after 3 days post-surgery.
x Usually due to viral reactivation.
x Treated with steroids.
x Good recovery is anticipated.
x In cases of delayed complete paralysis:
o The patient is followed up with
electrodiagnostic tests to determine degree
of injury.
o Loss of electrical excitability > 90%
degeneration by ENoG within 14 days of
mastoid surgery is an indication for nerve
exploration.

- Operative injuries to Facial nerve can be avoided if attention is

paid to the following:
1. Anatomical knowledge of Facial nerve course, possible variations
and anomalies and its surgical landmarks.
2. Always working along course of nerve and never across it.
3. Constant irrigation when drilling, to avoid thermal injury.
4. Use diamond burr when working near the nerve.
5. Gentle handling of the nerve when it is exposed, avoiding any
pressure of instruments on the nerve.
6. Not to remove any granulations that penetrate the nerve.
7. Using magnification; never to work on facial nerve without an
operating microscope.

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Riyadh et al. Notes
615
- Surgical Landmarks of Facial Nerve in Ear and Mastoid Surgery:
1. Processus Cochleariformis:
ƒ Geniculate ganglion (1st Genu) lies Anterior to it.
ƒ Tympanic segment of CN-VII starts at this level.
2. Horizontal SCC:
ƒ Tympanic segment of CN-VII runs below Horizontal SCC.
ƒ 2nd Genu of Facial nerve runs Infero-lateral to Horizontal
SCC.
3. Oval Window:
ƒ Tympanic segment of CN-VII runs above Oval window
(Stapes).
4. Short Process of Incus:
ƒ Tympanic segment of CN-VII lies medial to Short process
of Incus at level of Aditus.
5. Pyramid:
ƒ Mastoid segment of CN-VII runs behind Pyramid and
Posterior Tympanic sulcus.
6. Facial Recess:
ƒ Long process of Incus points toward Facial recess.
ƒ Chorda tympani nerve serves at Lateral margin of
Triangular facial recess.
ƒ Chorda tympani nerve can be exposed along its length
and can be followed inferiorly and medially to its takeoff
from the main trunk of Facial nerve.
7. TympanoMastoid suture:
ƒ Mastoid segment of CN-VII runs behind this suture.
8. Digastric Ridge:
ƒ Mastoid segment of CN-VII leaves Mastoid at Anterior end
of Digastric Ridge.

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616
- Surgical Landmarks of Facial Nerve in Parotid Surgery:
1. Cartilaginous Pointer:
ƒ Sharp triangular piece of cartilage of Pinna points to
Facial Nerve.
ƒ Extra-Temporal part of Facial Nerve lies 1 cm inferior and
medial to the pointer.
2. Tympanomastoid Suture:
ƒ Between Mastoid and Tympanic part of Temporal bone.
ƒ Facial Nerve lies 6-8 mm deep to this suture in
Stylomastoid foramen.
3. Styloid Process:
ƒ Facial Nerve crosses lateral to Styloid process.
4. Posterior belly of Digastric:
ƒ Facial Nerve lies between attachment of Posterior belly of
digastric muscle to Digastric groove and Styloid process.

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617
Herpes Zoster Oticus (Ramsay Hunt Syndrome):

- 3rd most common cause of facial nerve paralysis.

- Herpes zoster induced Facial nerve palsy.
- Pathophysiology:
o Reactivation of latent Varicella zoster virus (VZV) in Geniculate
ganglion of CN-VII during a period of decreased cell mediated
immunity.
o Rising titers of antibodies to VZV.
- Compared to Bell’s palsy:
o More severe symptoms.
o Worse prognosis with residual weakness in 30-50% of patients.
o Higher involvement of other cranial nerves.
- Clinical picture:
o Acute Peripheral Facial Palsy.
o Severe otalgia.
o Painful vesicular eruption in Concha, EAC or TM:
ƒ Occurs simultaneously with the paralysis in most cases.
ƒ May precedes the paralysis in 25% of cases, and has a
higher chance of recovery.
o SNHL and vertigo:
ƒ Involvement of CN-VIII (30% of cases).
o Herpes zoster ophthalmicus:
ƒ Involvement of ophthalmic division (V1) of trigeminal
nerve.
ƒ Include uveitis, keratoconjunctivitis, optic neuritis and
glaucoma.

- Treatment:
1. Oral Prednisone:
ƒ Relieve acute pain.
ƒ Reduce vertigo.
ƒ Decrease incidence of post-herpetic neuralgia.
2. Oral Anti-viral:
ƒ Acyclovir 800 mg PO 5 times daily for 10 days, or
ƒ Valacyclovir 1g PO TID for 5 days.
3. Eye Care.

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Riyadh et al. Notes
618
Otitis Media:
- AOM:
o Toxic effects from infectious spread into the nerve sheath
results in facial nerve dysfunction.
o Dehiscence in Fallopian canal may serve as portals for direct
bacterial invasion and inflammation along the nerve.
o Facial paralysis may begin within a few days of onset of an
acute otitis media and is usually incomplete.
o Treatment includes myringotomy, drainage, C/S and Antibiotic.
o Facial palsy associated with acute otitis media generally resolves
with aggressive management of the infection.
- CSOM:
o Facial nerve paralysis may occur from compressive effects from
a cholesteatoma or from granulation tissue.
o Progressive unilateral facial palsy with suppurative otitis media.
o CT may reveal cholesteatoma or soft tissue compression.
o Tympanomastoidectomy should be performed as soon as
possible with facial nerve exploration and decompression
without opening the perineurium.

Malignant (Necrotizing) Otitis Externa:

- Progressive unilateral facial palsy due to Facial nerve injury from the
effect of skull base osteomyelitis.
- Caused by pseudomonas infection in immuno-compromised patients.
- Clinical picture:
o Granulation tissue in EAC at bony-cartilagenous junction.
o Persistent otalgia and otorrhea.
o Cranial nerve involvement (CN-VII > CN-X > CN-XI)
- Diagnosis:
o History and Physical exam.
o Elevated ESR.
o CT Temporal bone.
o Technetium 99 bone scan:
ƒ Evaluates osteoblastic activity.
ƒ Excellent for Diagnosis of Acute or chronic process.
ƒ Positive for prolonged period.
o Gallium 67 bone scan:
ƒ Evaluates Inflammation
ƒ Excellent for Follow up the course.
ƒ Fades if disease resolves.
o Biopsy with culture of EAC.
- Management:
o Prolonged IV anti-pseudomonas antibiotics (6-8 weeks)
o Anti-pseudomonas Antibiotics ear drops.
o Aggressive Diabetic control.
o Meticulous cleaning and debridement.
o Surgical debridement if medical management failed.

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619
Tumors of the Skull Base and Facial Nerve:

- 5% present with facial paralysis.

- Suspected in the following cases:
1. Slow progression over > 3 weeks.
2. No return of facial function over time (> 3 months).
3. Recurrent ipsilateral paralysis.
4. Concurrent facial twitching with slow paresis.
5. Multiple cranial nerve deficits.
6. Presence of neck or parotid mass.
7. History of cutaneous malignancy.
8. Chronic ET dysfunction with no history of middle ear disease.

- Most common tumor of the facial nerve is facial schwannoma:

o If in CP angle or IAC, present with hearing loss/vertigo.
o Extra-temporal rarely have paralysis; parotid mass instead.
o Geniculate ganglion and labyrinthine most common sites.
o Need interposition graft; Grade III is the best outcome.
o If young, operate early; if old, watch it grow.

- Most common malignancy to cause facial nerve paralysis is parotid

tumors:
o Mucoepidermoid carcinoma is the most common tumor to cause
facial dysfunction, although adenoid cystic carcinoma has a
higher rate of neural involvement.

- If malignant tumors involving the facial nerve:

o Typically require excision with tumor-free margin.
o Except (spare the facial nerve intra-operatively):
ƒ Lymphoma
ƒ Leukemic invasion
ƒ Low-grade parotid lesions

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Melkersson-Rosenthal Syndrome:

- Idiopathic disorder.
- Begins in 2nd decade of life.
- Symptoms appears sequentially and rarely simultaneously.
- Triad:
1. Recurrent orofacial edema:
ƒ Defining feature.
ƒ Non-pitting edema.
ƒ Cannot be explained by any other cause.
2. Recurrent facial paralysis:
ƒ Occurs in 50% of patients.
ƒ Unilateral or bilateral.
3. Fissured tongue (Lingua plicata):
- Diagnosis:
o Biopsy of lip:
ƒ Non-caseating epithelioid cell granulomas surrounded by
histiocytes, plasma cells and lymphocytes.
- Treatment:
o Multiple treatments have been tried (steroids, metronidazole,
dapsone, acyclovir and methotrexate) without a consistent
response to therapy.

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621
Bilateral Facial Paralysis:

- Has higher incidence of systemic causes than unilateral palsy.

- Mostly associated with other neurologic signs.
- Requires careful work-up:
o Full neurologic examination:
ƒ Detect other cranial neuropathy.
o Serology:
ƒ Blood chemistry.
ƒ Blood culture.
ƒ VDRL for syphilis.
o Lumbar puncture:
ƒ For cytological studies.
o MRI:
ƒ Exclude space occupying lesions.

- Most common causes:

o Guillain-Barré syndrome:
ƒ Most common cause in adults.
ƒ Progressive ascending motor paralysis after viral infection
ƒ Usually affects initially the lower limbs.
ƒ Diagnosed based on typical clinical picture and presence
of elevated spinal fluid protein with normal cell count.
o Lyme disease:
ƒ Most common cause in children.
ƒ Responsible for half of all cases of pediatric facial
paralysis in endemic areas.
o Bell’s palsy (0.3%)
o Pontine tumor
o Benign intracranial hypertension (BIH)
o Bilateral Neurofibromas (Neurofibromatosis type 2).
o Bacterial meningitis.
o Brainstem encephalitis
o Myasthenia Gravis
o Syphilis
o Leukemia
o Sarcoidosis:
ƒ Chronic non-caseating granulomatous disease.
ƒ Heerfordt syndrome (Uveoparotid fever):
x Non-suppurative parotitis
x Uveitis
x Mild fever
x Cranial nerve paralysis (Mainly facial paralysis).
o From direct invasion of facial nerve by the
granulomatous process.

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622
Facial Paralysis in Newborns:

- Important to different between true congenital paralysis and birth

trauma.

- Birth Trauma (80%):

o Most common cause of unilateral facial paralysis in neonates.
o Pathophysiology:
ƒ Extra-temporal part of facial nerve is at risk for
compressing injury during delivery as it courses the
underdeveloped mastoid process.
ƒ Intrauterine facial nerve injury can occur from pressure
on infant’s face by sacral prominence during birth.
o Risks:
ƒ Forceps delivery.
ƒ Prolonged delivery (primiparity).
ƒ Large infant (BW>3.5 kg).
o Clinical picture:
ƒ Asymmetric crying face
ƒ Facial contusion
ƒ Hemotympanum
ƒ Peri-auricular ecchymosis
o Diagnosis (Done for complete paralysis):
ƒ EMG (preserved neuromuscular activity suggests
inherited or developmental etiology)
ƒ Electrophysiological testing within first three days.
ƒ ABR (evaluate for associated hearing loss)
o Management:
ƒ Observation.
ƒ Prognosis for spontaneous recovery is excellent

- Congenital Unilateral Lower Lip Palsy:

o Most common true congenital cause of facial paralysis.
o Due to hypoplasia of depressor labii inferioris muscle.
o Associated with cardiac defects (≈10%).

- Möbius Syndrome:
o Wide spectrum of abnormalities secondary to central brain stem
and peripheral neuromuscular defects.
ƒ Bilateral or unilateral Facial and Abducens nerve palsies.
ƒ Club foot (talipes equinovarus).
ƒ Tongue weakness.
ƒ Mixed hearing loss.
ƒ Mental retardation.
ƒ External ear deformities.
ƒ Ophthalmoplegia.

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Sequelae and complications of Facial nerve paralysis:

1. Incomplete recovery:
o Largest portion of Facial nerve is composed of Efferent fibers
that stimulate muscles of facial expression.
ƒ Suboptimal regeneration of this portion results in paresis
of all or some of these facial muscles.
o Dysgeusia (impairment of taste) or Ageusia (loss of taste) may
occur with incomplete regeneration of Chorda tympani.
o Treated with facial re-animation producers.

2. Aberrant re-innervation of the facial nerve:

o Synkinesis is condition in which involuntary movements
accompany voluntary movements.
o During regeneration, some neural fibers may take an unusual
course and connect to neighboring muscle fibers.
o Produces unusual neurologic pathways.
o When voluntary movements are initiated, they are accompanied
by involuntary movements (eg, eye closure associated with lip
pursing or mouth grimacing that occurs during blinking of the
eye).
o Improved with Botox injections.

3. Exposure keratitis:
o Eye cannot be closed, tear film from the cornea evaporates
causing dryness, exposure keratitis and corneal ulcer.
o Worse when tear production is also affected.
o Prevented by:
ƒ Eye care:
x Artificial tears every 1-2 hours
x Eye ointment and proper cover for the eye at night.
ƒ Tarsorrhaphy:
x Upper and lower eyelids are partially sewn.
x Indicated temporarily for severe cases.
ƒ Upper eyelid gold-weight implant:
x Indicated for patients with long-term complete
facial paralysis to improve eye closure.
x Upper eyelid gold-weight implant sutured to the
tarsal plate deep to levator palpebrae muscle.

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624
4. Contractures:
o Result from fibrosis of atrophied muscles or fixed contraction of
a group of muscles.
o Affect movements of face but facial symmetry at rest is good.

5. Bogorad’s syndrome (Gustatory Lacrimation/Crocodile tears):

o Unilateral lacrimation during mastication.
o Etiology:
ƒ Insult to facial nerve.
ƒ Causes:
x Trauma (temporal bone trauma)
x Bell’s palsy
o Pathophysiology:
ƒ Insult proximal to geniculate ganglion (Most common):
x Aberrant cross-reinnervation between preganglionic
secretomotor parasympathetic fibers to
submandibular and sublingual glands (Chorda
Tympani) and the preganglionic parasympathetic
fibers to lacrimal gland (Greater superficial petrosal
nerve).
ƒ Insult distal to geniculate ganglion:
x Aberrant cross-reinnervation between preganglionic
secretomotor parasympathetic fibers to parotid
gland (Lesser petrosal nerve) and the preganglionic
parasympathetic fibers to lacrimal gland (Greater
superficial petrosal nerve).
o Treatment:
ƒ Botox injection into lacrimal gland.
ƒ Surgical management (Vidian neurectomy).

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625
6. Frey's syndrome (Gustatory sweating):
o Auriculo-temporal nerve syndrome.
o Unilateral facial skin flushing and sweating during mastication.
o Occurs within first year of insult, but may be delayed more.
o Etiology:
ƒ Insult to the auriculo-temporal nerve.
ƒ Causes:
x Iatrogenic (Parotid surgery):
o Most common cause.
o Occurs in 30-60% of patients.
o Symptomatic Frey syndrome occurs in 10%
only of these patients.
x Blunt trauma
x Infection (Bell’s palsy, Herpes zoster).
o Pathophysiology:
ƒ Aberrant cross-reinnervation between postganglionic
secretomotor parasympathetic fibers to parotid gland
(Auriculotemporal nerve) and the postganglionic
sympathetic fibers that supply the sweat glands of skin.
ƒ Occurs as both sympathetic and parasympathetic fibers
use acetylcholine neurotransmitters.

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Riyadh et al. Notes
626
o Diagnosis:
ƒ Minor starch-iodine test:
x Objective test to confirm the diagnosis.
x Method:
o Ipsilateral side of face and neck is painted
with iodine solution and allowed to dry.
o Starch powder is dusted over the painted
area.
o Patient is allowed to chews on a sialagogue
such as a lemon wedge, for several minutes.
o Appearance of dark blue spots as a results
of the reaction of dissolved starch with iodine
confirms the diagnosis.
x Positive in 96% of patients underwent parotid
surgery even if they didn’t complaint clinically.

o Treatment:
ƒ Observation:
x For non-bothersome symptoms.
ƒ Medical management:
x Topical Anti-perspirant
x Topical Anticholinergic (Glycopyrrolate lotion)
x Botox injections (excellent control for prolonged
periods).
ƒ Surgical management (rarely indicated):
x Placement of inter-positional barriers:
o Fat, acellular dermal grafts or muscle flap.
x Tympanic neuronectomy:
o Controversial.
o Jacobson’s nerve section via tympanotomy
approach.
o High incidence of recurrence.

o Prevention during parotid surgery:

ƒ Elevation of a thick skin flap.
ƒ Performance of partial parotidectomy.
ƒ Placement of inter-positional barriers (fat, acellular
dermal grafts or muscle flap).

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627
Facial Nerve Rehabilitation (Repair and Reanimation)

- Goals of Facial Rehabilitation:

o Functional:
ƒ Protect the eye from corneal exposure.
ƒ Improve sphincteric function of eye and mouth
x Improve drooling and articulation.
o Cosmetic:
ƒ Provide a balanced smile.
ƒ Provide symmetry at rest.

- General principles:
o Whenever the continuity of facial nerve has been disrupted,
every effort should be made to restore its continuity.
o Early exploration and nerve repair is performed when possible.
o If concomitant injuries prohibit immediate direct repair, the
wound should be explored and nerve ends tagged for future
exploration.
o Nerve injuries medial to the lateral canthus do not require repair
because of extensive crossover.
o Eye care should be continued during the planning time
for surgical correction.

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Riyadh et al. Notes
628
o Early management of facial paralysis (<2 years):
ƒ Ideally nerve repair should be done within 3 days of
injury as the distal branches can be stimulated to help in
identification.
ƒ Re-innervation is best within 6 months post-paralysis.
ƒ All nerve repair methods produce synkinesis but
sphincteric function of the mouth and eye are restored.
ƒ Best result for any nerve repair surgery is HB grade III.
ƒ In Electrodiagnostic tests:
x EMG is showing fibrillation potentials.
x Muscles are not de-innervated.
x No muscle atrophy or loss of motor end plates.
ƒ Methods of early facial re-innervation:
1. Primary end-to-end anastomosis (Neurorrhaphy)
2. Interposition (cable) graft
3. Cross-facial nerve graft
4. Nerve transfer

o Delayed management of facial paralysis (>2 years):

ƒ In Electrodiagnostic tests:
x EMG is showing Electrical silence.
x Muscles are atrophied.
x No functioning motor end plates.
ƒ Important to identify which aspects of facial paralysis are
most troublesome for the patient, so you can treat each
region of the face separately:
ƒ Methods of Delayed facial rehabilitations:
1. Dynamic procedures:
o Muscle transfer:
x Indicated for adults (<50 years) with
average motivation.
o Free Nerve Muscle Transfer:
x Indicated for adults (<50 years) with
high motivation.
2. Static procedures:
o Indications:
x Old patients (>50 years).
x Adults with low motivation.
o Types:
x Static slings.
x Static excisional procedures.

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629

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Riyadh et al. Notes
630
- Methods of Early Facial Rehabilitation:

1. Primary End-to-end Anastomosis (Neurorrhaphy):

ƒ Indications:
x Recent injury and tension-free closure is
possible:
o Proximal and distal ends should be presents.
o Preferred to be done within 3 days of injury.
o Can be done up to 3 weeks of injury.
ƒ Method:
x Injured ends of the nerve should be freshened at
45-degree angle to expose more neural tubules
and improves regrowth of the nerve.
x Microsurgical anastomosis of epineurium with non-
absorbable 10-0 nylon sutures.
x Application of glue without sutures can be done if
the nerve within the fallopian canal and there was
is no chance of nerve end movement.
x Avoidance of tension is essential which may require
releasing proximally and distally or rerouting at the
mastoid segment.
x Priority of repair must be given to zygomatic and
buccal branches if facial nerve was sacrificed during
parotid surgery for malignancy.
ƒ Advantages:
x Provides best chance of rehabilitation (facial muscle
movement with the least synkinesis).

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Riyadh et al. Notes
631
2. Interposition (Cable) Grafting:
ƒ Indications:
x Recent injury and tension-free closure is NOT
possible:
o Proximal and distal ends should be presents.
o Gap > 1-2 cm between the two ends.
o Preferred to be done within 3 days of injury.
o Can be done up to 3 weeks of injury.
ƒ Method:
x Nerve graft interposed between facial nerve
endings.
x Options:
o Greater auricular nerve is the preferred
graft as it is readily available near operative
field and has same diameter of facial nerve.
o Sural nerve graft is used if length > 10 cm
is required.
x Follow same principles of primary anastomosis.
ƒ Advantages:
x Provides resting muscle tone and spontaneous
facial expression.
ƒ Disadvantages:
x Nerve grafting produces more synkinesis.

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Riyadh et al. Notes
632
3. Cross-Facial Nerve Graft (CFNG):
ƒ Indications:
x Nerve injury with unavailable proximal stump
and intact motor end plates:
o Contralateral facial nerve is available.
o Preferred to be done within 6 months of
injury.
o Can be done up to 2 years of injury.
ƒ Method:
x 1st stage:
o Proximal branches of facial nerve (mainly
buccal branch) from normal side are coapted
to distal end of sural nerve graft.
o Tunneled subcutaneously under the upper lip
to reach the opposite side.
o Banked in the upper buccal sulcus just past
the midline.
x 2nd stage:
o Performed 6-12 months after 1st stage.
o Distal end of the sural nerve graft then
coapted to corresponding branches supplying
specific muscle groups on the paralyzed side.
ƒ Advantages:
x Provides spontaneous animation.
ƒ Disadvantages:
x Risk of synkinesis.
x Violation of the normal facial nerve.
x Axonal regeneration takes a long time to cross the
face and could lead to irreversible muscle atrophy:
o Mainly if done after > 6 months of injury.
o Needs to keep the facial muscles alive by
baby setting them to another nerve.
o Mainly nerve used is the ipsilateral nerve to
masseter (branch from V3 of CN-V).
o Done during the 1st stage of CFNG.

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633
4. Nerve Transfer:
ƒ Indications:
x Nerve injury with unavailable proximal stump
and intact motor end plates:
o Preferred to be done within 6 months of
injury.
o Can be done up to 2 years of injury.
ƒ Method:
x Uses branches of other nerves to innervate the
ipsilateral distal stump of facial nerve.
x Types of nerve transfer:
o Hypoglossal-Facial Nerve Transfer:
ƒ Most commonly used procedure.
ƒ Different methods:
1. Entire CN-XII transection and
coaptation to main trunk of the
facial nerve.
2. Split CN-XII transection (40%)
and coaptation to lower division
of the facial nerve.
3. End-to-side neurorrhaphy
between CN-XII and donor
cable nerve graft (great
auricular nerve) and coaptation
to main trunk of the facial
nerve.

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Riyadh et al. Notes
634
o Masseteric-Facial Nerve Transfer:
ƒ It is increasingly being used for facial
reanimation.
ƒ Good option due to its minimal donor
morbidity.

ƒ Advantages:
x Excellent muscle tone
x Provides potentially greater number of axons.
x Restores some voluntary motion and resting tone
typically by 6 months.
x Can be used as a “babysitter” (to maintain muscle
innervation) during the long period of axonal
regeneration through a cross-facial graft.
ƒ Disadvantages:
x Lack of spontaneous expression.
x Alteration of expression with chewing.
x Requires patient re-education of motor
coordination.
x Risk of hemitongue weakness.
x Risk of significant synkinesis.

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- Methods of Delayed Facial Rehabilitation:

1. Dynamic Procedures:
ƒ Indications:
x Prolonged nerve injury with unavailable
proximal stump and loss of motor end plates:
o Done after 2 years of injury.
ƒ Aim:
x Restore symmetry both at rest and while smiling.
ƒ Types:
x Muscle Transfer:
o Indication:
ƒ Adults (<50 years) with average
motivation.
o Advantages:
ƒ One stage procedures.
o Disadvantages:
ƒ Patients must clench the teeth to
produce a smile.

x Free Nerve Muscle Transfer:

o Indication:
ƒ Adults (<50 years) with high
motivation.
o Advantages:
ƒ Spontaneous animation of the smile.
ƒ Potential of achieving individual
segmental contractions.
ƒ Reduction of synkinesis.
o Disadvantages:
ƒ Lengthy procedures with two stages.
ƒ Requires innervation.
ƒ Requires postoperative physiotherapy.

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636
- Common types of Muscle Transfer:

1. Temporalis Muscle Transfer:

ƒ Innervated by CN-V.
ƒ Methods:
x Temporalis is detached form temporal fossa and
turned over the zygomatic arch to reach the oral
commissure.
x Used mainly to reanimates the mouth using the
horizontal vector.
x Superior vector is used to reanimates eye.
ƒ Disadvantages:
x Patients must clench the teeth to produce a smile.
x Not very effective for eyelid closure.
x Produces significant temporal hallow and bulge
over the zygomatic arch.

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2. Masseter Muscle Transfer:
ƒ Innervated by CN-V.
ƒ Used when temporalis muscle is not opted.
ƒ May be preferred due to avoidance of large facial incision.
ƒ Disadvantage:
x Less available muscle compared to temporalis
x Vector of pull on oral commisure is more horizontal
than superior/oblique like temporalis.

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638
- Common types of Free Nerve Muscle Transfer:

1. Gracilis Muscle Flap:

ƒ Workhorse for free muscle transfer.
ƒ Long, thin muscle in medial thigh.
ƒ Methods:
x Can be done as one or two stages depending on
the method of innervation.
o One-stage procedure:
ƒ Gracilis muscle transfer.
ƒ Vascular anastomosis to the facial
artery and vein or to superficial
temporal vessels.
ƒ Obturator nerve of gracilis connected
to either:
- Ipsilateral CN-VII (if present).
- Masseter nerve.
o Two-stage procedure:
ƒ 1st Stage:
- Cross-face nerve graft with
sural nerve graft.
ƒ 2nd Stage:
- Performed after 6-12 months of
CFNG.
- Gracilis muscle transfer
performed after neural ingrowth
of graft.
- Vascular anastomosis to the
facial artery and vein or to
superficial temporal vessels.
- Obturator nerve of gracilis
connected to distal end of sural
nerve graft.

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640
2. Static Procedures:
ƒ Indications:
x Prolonged nerve injury with unavailable
proximal stump and loss of motor end plates:
o Done after 2 years of injury.
ƒ Aim:
x Restore symmetry at rest only.
ƒ Indication:
x Old patients (>50 years).
x Adults with low motivation.
ƒ Types:
x Static slings:
o Fascial, allograft, or synthetic (Gore-Tex).
o Commonly used:
ƒ Palmaris longus tendon.
ƒ Tensor fascia lata.
x Static excisional procedures.
ƒ Regions:
x Eye brow procedures:
o Used to correct eye brow ptosis.
o Static excisional procedures:
ƒ Brow lift (Most common).

x Upper eyelid procedures:

o Used to correct lagophthalmus.
o Most common is gold weight
and tarsorraphy.

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641
x Lower eyelid procedures:
o Used to correct lid eversion and ectropion.
o Static excisional procedures:
ƒ Horizontal lid shortening (Most
common).
o Static slings:
ƒ Palmaris longus tendon.
ƒ Tensor fascia lata.

x Nasal valve procedures:

o Used to correct nasal valve collapse.
o Static excisional procedures:
ƒ Septoplasty.
o Static slings:
ƒ Palmaris longus tendon.
ƒ Tensor fascia lata.

x Upper lip and cheek procedures:

o Used for smile reconstruction.
o Static slings:
ƒ Palmaris longus tendon
ƒ Tensor fascia lata.
o Principles:
ƒ Slings weaved from oral commissure
and upper lip to temporalis fascia or
zygoma.
ƒ Over correction is made to allow for
stretching.
ƒ Usually 3 slings applied.
ƒ Can be combined with dynamic
procedures.

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x Lower lip procedures:
o Used to correct the inability
to depress, lateralize, and evert lower lip.
o Static excisional procedures:
ƒ Wedge excision of affected side.
ƒ Resection of normal side
depressor labii inferioris muscle
o Botox injection to normal side to weaken the
depressor labii inferioris.

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CSF Otorrhea

- Leakage of (CSF) though the ear structures is a rare but potentially

life-threatening situation that requires rapid intervention.
- The presence of an abnormal communication of the sterile
subarachnoid space with the flora of the sinonasal tract places the
patient at great risk for meningitis.
- An episode of meningitis may be the presenting problem for a person
with an otologic CSF leak.
- Actual leakage of the fluid from the ear is not always present.
- CSF otorrhea occurs only if a perforation in the eardrum or a defect in
the external ear canal is present. (trauma, surgery)

- However, in the absence of such a defect, the fluid flows down the
eustachian tube and manifests as a clear rhinorrhea.

- (Remember; just because the leak is through the nose does not mean
that an otologic source is not a possibility.)

Etiology:
- Violation of the bony and meningeal barriers that separate the
subarachnoid space from the middle ear and mastoid
- Defect must exist not only in the bone, but also in the dura mater

*: Traumatic (most common)

• Accidental (80%) – 90% will close spontaneously (manitoba)
• Surgical/iatrogenic (16%)

*: Nontraumatic (4%)
• High pressure – Tumors, Hydrocephalus
• Normal pressure – Congenital, Spontaneous,
Osteitis/Osteomyelitis/otologic disease itself

Sometimes broadly be categorized into acquired and congenital

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Spontaneous cerebrospinal fluid leak

- Leakage that occurs without an obvious antecedent pathology.

- Spontaneous leakage represents the greatest challenge to the clinician
because the source of the leakage is not readily obvious
- Rare, with less than 500 cases having been reported in the literature
worldwide
- More common in children (72%) than adults.
- Such leakage is usually due to some congenital defect in the
temporal bone.
- Although congenital sources are more common in children, they can
occur in people of any age and can even be observed in the geriatric
population
- Bony dehiscences are most commonly found on the floor of the middle
fossa, along the tegmen plate.
- Continuous pressure of the CSF over the years results in formation of
a meningocele or encephalocele.
- Defects in the middle fossa are associated with 88% of spontaneous
leaks in adults.
- Most common Sites of Middle Ear CSF Leak
1. Tegmen
2. Fallopian canal
3. Hyrtl’s fissure

- The remainder of spontaneous leaks are due to posterior fossa defects

and arachnoid granulations
- Spontaneous leaks have recently been shown to be often associated
with increased intracranial pressure.
- This is often manifested by a partially empty sella on the MRI scan.

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Congenital causes of CSF Otorrhea

1: Bony Tegmen defect

(Most common congenital, but present later in life)

2: Arachnoid granulations
(“spontaneous”, also present later in life)

3: Mondini
- Autosomal D
- There is incomplete partition between the scalae apical and
middle turn due to absence of osseous spinal lamina.
- Condition is unilateral or bilateral.
- Triad of IP type II with a minimally dilated vestibule and
large vestibular aqueduct
- This deformity may be seen in Pendred, Waardenburg, Branchio-oto-
renal, Treacher-Collins and Wildervanch syndromes
- Have a patency at the lateral aspect of their internal auditory
canal, allowing direct movement of CSF into the inner ear.
- A second defect, usually of the annular ring of the stapes
footplate (OVAL W) then results in drainage of CSF into the
middle ear.
- This usually causes loss of the remainder of hearing.

4: Enlarged Cochlear Aqueduct or vestibuler

5: Enlarged Fallopian Canal

6: Patent Hyrtl’s fissure

- A congenital fusion plane found between the otic
capsule and the jugular bulb
- (A bony cleft inferior to the round window niche
and running towards the posterior fossa)
- (Also termed the tympanomeningeal fissure).
- Such leakage may not be associated with any
inner ear abnormalities, and the patient may
have no evidence of a sensorineural hearing loss.

7: Petromastoid canal fissure

- Normally carries the subarcuate artery.

- Such patients may present with recurrent bouts of meningitis
associated with what appears to be a unilateral serous otitis.
- Frequently, the true nature of the problem is not realized until a
myringotomy is performed

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646
Acquired cerebrospinal fluid leak

- Result from temporal bone trauma, surgery, or infectious or neoplastic

causes
- Far more common than
- Congenital leakage.

Postoperative leakage following surgery is probably the most

common cause of acquired CSF leaks.
- It is a recognized complication of acoustic neuroma removal and other
skull base surgery.
- Leaks as a postoperative complication of skull base surgery represent
the bulk of cases.
- This complication has been reported to occur in 6-12% of such cases
- These leaks are usually evident in the early postoperative period.
- They rarely occur more than 2 months postoperatively.
- Mastoid surgery for chronic ear disease is also a potential cause of an
acquired CSF leak.
- When the dura is violated intraoperatively, the defect should be
repaired immediately if possible.
- Frequently, however, the dura is not injured, but a defect is left in the
bony plate of the tegmen.
- Over the years, the continuous pulsations of the CSF cause the dura to
thin, allowing the arachnoid or brain to prolapse through this defect.
(encephalocele)
- This dura may become thin and spontaneously rupture, resulting in a
leak of CSF

Temporal bone fracture

x Leakage as a result of temporal bone fracture is the second most
common etiology and occurs in 17- 21%
x Otic capsule sparing fracture (Longitudinal):
ƒ CSF from floor of middle cranial fossa.
ƒ Drains into epitympanum, antrum, and mastoid air cells

o Otic capsule disrupting fracture (Transverse):

ƒ CSF from Posterior cranial fossa.
ƒ Drains through Disrupted otic capsule into Middle ear.

o Otic capsule does not heal fully

ƒ Fibrous tissue and periosteal bone may seal off the
fracture.
o Immediate vs delayed leaks (> 1 week)

Similar problems may result from middle ear disease, most notably
cholesteatoma

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647
Presentation

- CSF otorrhea
- CSF rhinorrhea
- Salt taste
- Leak with position or strain
- Hearing loss
- Meningitis
- Seizure

- CSF leakage through the ear is present is a clear watery drainage from
the ear.
- This, however, is not always present and does not occur unless the
eardrum or canal is in some way violated.
- Leakage may be evident as a clear watery nasal discharge.
- This discharge may be Positional or intermittent in nature
- May only become apparent during straining or leaning forward.
- Strange salty taste in the back of the throat.

- Unilateral hearing loss. (The nature of the hearing loss is important)

ƒ Sensorineural hearing loss suggests an associated abnormality of the

inner ear (associated with spontaneous leaks in children and is present
82% of the time)

ƒ Conductive, suggesting a leak elsewhere in the temporal bone (OME)

May only be recognised at the time of myringotomy (gusher)
If that happened:
o The ear canal is often packed to prevent continuous drainage from the
ear and allow the eardrum to heal
o Other authors think that packing may cause stasis and provide a nidus
for infection, hastening meningitis, and they recommend only a loosely
placed, frequently changed sterile cotton ball placed in the conchal
bowl.
o Then conservative Tx measures

- Unexplained episode of meningitis. (A common presentation)

- It is found in 93% of children and 36% of adults with spontaneous CSF
leakage.
- A history of unilateral hearing loss or chronic ear disease may suggest
which side is involved.
- Absence of otologic symptoms and a history of sinonasal disease may
suggest an anterior source of leak.
- In situations of leakage following surgery and trauma, the source of
the leak usually is readily apparent

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Physical examination

- Complete otologic, neurologic, and head and neck examination

- Microscopy to examine the ears.
- Pneumatic otoscopy may be helpful in demonstrating fluid within the
middle ear space
- Tuning fork evaluations
- Audiometric evaluation.

An important part of the physical examination is an attempt to demonstrate

the leak. (Straining, leaning)

Dandy maneuver, the patient leans forward with the head pointed down
while performing a Valsalva.

The side of the nostril from which the leakage occurs usually agrees with
the side of the otologic source.

Investigations:
Done if obvious cause like trauma or surgery not found:

x Halo sign

x Test for Glucose and protein content

x B2 Transferrin (Most sensitive measure of identifying CSF)

(differentiate from perilymph by amount and rate)
x Beta trace protein

x High resolotion CT orCT Cisternography

- Unless an otologic source is certain, the scan should cover all 3 cranial
fossae.
- Check the otic capsule for abnormal morphology, such as a Mondini
deformity.
- Note the sizes of the vestibular and cochlear aqueducts.
- Check the tegmen plates of the posterior and middle fossae for defects
- CT scanning may be enhanced with the use of intrathecal contrast,
such as iopamidol or iohexol.
- The presence and location of pneumocephalus on CT scanning may
help to identify and localize a CSF leak

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x MRI
- Spinal fluid, bright on T2 sequences
- In cases where a tegmen defect is observed on CT scanning, MRI may
demonstrate whether or not brain tissue is prolapsed into the middle
ear
- Because this is important information for surgical planning, an MRI is a
critical adjunct
- A partially empty sella has recently been recognized as a possible sign
of increased intracranial pressure.
- The increased CSF pressure causes infiltration of the sella with CSF and
displacement of the pituitary tissue
- Has been shown to occur in 71% of patients with spontaneous CSF
leaks.

x Intrathecal Fluorescein (0.1 cc of 10% Fluorescein in 10 cc ofCSF)

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Management:

Conservative:

- Leak secondary to recent surgery or trauma can often be treated

conservatively
- Treatment Options for CSF leak

x Bedrest with Head Elevation, avoid increased ICP (avoid straining, stool
softeners)
x Compression dressing (Postmastoidectomy)
x Lumbar Drain or serial lumbar taps if conservative measures fail
x Diuretics (eg, furosemide, hydrochlorothiazide),
x Carbonic anhydrase inhibitors (eg, acetazolamide)
x Steroids.

x Prophylactic antibiotics is controversial but needed in case of drain or

pack placed, immunosuppressed and when soilage of the central
nervous

x Antibiotics should be withheld unless signs and symptoms of meningitis

occur

A 25-year Meta-analysis by Brodie (1997) suggested statistically significant

reduction in meningitis using prophylactic antibiotics.

However, a Cochrane review in 2011 showed no benefit and does not support
prophylactic antibiotic use in patients with Basilar Skull Fractures, whether
there is evidence of CSF leakage or not.

- Spinal fluid leaks following acoustic neuroma surgery respond to this

treatment 80% of the time
- Leaks associated with temporal bone fractures, which almost always
seal in 3-4 weeks with this conservative therapy

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Surgical Therapy:

Indications for Open Exploration of CSF leak

ƒ Persistent leak despite Medical Management (10-14 days)

ƒ Large Defect
ƒ Brain/Meningeal Herniation
ƒ Brain Penetration by bony Spicule
ƒ Persistent Pneumocephalus
ƒ Recurrent Meningitis
ƒ ? Gravity dependant defect location
ƒ Primary treatment of a spontaneous otogenic spinal fluid leak

Approaches:

1) Transcanal approach
- Spontaneous leaks in children with otic capsule defects
- Such as Mondini
Because rarely any hearing is present, a stapedectomy is usually
performed and the oval window obliterated with soft tissue
- Can also be used in some cases of CSF leakage due to a patent Hyrtl
fissure

2) Transmastoid approach
- If the leakis related to a small ( < 1 cm) defect in the bone of the
tegmen or exact site not really known
- Exposure of a mastoidectomy usually allows excellent visualization of
the leakage site.
- The site can often be repaired with a small amount of fascia supported
by Gelfoam
- The fascial repair can be supported with a tragal cartilage graft placed
between the intact bony edges and the dura
- Occasionally, a fat or muscle graft may be needed.

- Leaks occurring from defects of the posterior cranial fossa anterior to

the sigmoid sinus present a special problem. This is the area of the
basal cistern, where no arachnoid mesh is present. Leakage from this
area is explosive and profuse and is not well controlled with fascia
alone. A large fat graft obliterating the mastoid is usually required

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3) Transmastoid with Obliteration
- Rare cases, the exact site of leakage is not found, and diffuse leak is
observed from multiple mastoid air-cell tracts.
- mastoid may need to be obliterated with fat.
- Obliteration of the middle ear and eustachian tube may also be
required, especially if the leakage is not limited to the mastoid

4) Blind sac surgery

- Previously undergone CWD mastoidectomy (or EAC eradicated by
disease)
- In these situations, the external ear and mastoid epithelium must be
completely removed and the ear canal sewn over.
- Abdominal fat is then used for obliteration

5) Middle fossa/transmastoid combined approach

- If a leak is due to a large (>1 cm) defect in the floor of the middle
fossa
- A mastoidectomy is performed first to identify the site of leakage.
- Do not attempt to reduce herniated brain tissue.
- Such encephaloceles do not contain functioning brain tissue and should
be excised using bipolar cautery.
- Once the defect is identified, use the middle fossa approach for repair.
- The middle fossa affords excellent visualization of the defect and an
opportunity to use the intact bony edges of the defect to hold any
repair material in place.
- Recommended repair of such large defects is with a 3-layer technique.
A layer of calvarial bone (from the craniotomy) is sandwiched between
2 layers of fascia.
- Fibrin glue is a very useful adjunct (not alone)

Grafts:

- Facia
- Muscle
- Cartilage
- Bone
- Biocompatible (hydroxy apetite, bpvin pericardium)
- Synthetic (silicone sheeting, Marlex mesh, titanium plates, and
Methylmethacrylate), high rate of extrusion

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653
Postoperative Details:

- Continuous lumbar spinal fluid drainage is an important adjunct to

surgical repair of otogenic CSF leakage

Drainage should be accomplished by draining a specific amount every hour,

usually about 10 mL. Occasionally, this causes severe headache, in which
case a smaller amount can be removed or the fluid can be removed less
frequently
(eg, 5 mL every half hour)

Check spinal fluid drainage every 2 days with a Gram stain and a culture.

The lumbar drain is usually left in place for 2-3 days postoperatively.
If no sign of leakage is present, it is clamped and the patient is observed for
an additional 24 hours.
If no further leakage is observed, the drain is then removed

- Observed in an ICU (any neurologic changes)

Perform hourly neurologic checks for the first 24 hours after surgery and
then every 2 hours until the patient is well enough to leave the unit

ICU may not even be necessary. These include cases treated by a transcanal
approach that do not require lumbar drainage

- Patients should remain on bed rest. Use position changes and

compression boots to prevent bedsores and deep venous thrombosis.

Complications:

o Intracranial bleeding
o Cerebral edema
o Hydrocephalus
o Stroke
o Meningitis

Change in mental status in the postoperative period must be rapidly

evaluated

An immediate CT scan of the brain performed without contrast usually

demonstrates any bleeding, edema, stroke, or hydrocephalus.

Clamp the drain until the CT scan findings are shown to be normal.

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Hearing Aids and Implantable Hearing Devices

HEARING AIDS

- The most common treatment for sensorineural hearing loss (SNHL) is

the use of hearing aid amplification
- Hearing aids are the principal means of auditory rehabilitation for
patients with sensorineural hearing loss (SNHL).
- Hearing aids may also play a role in the management of conductive
hearing losses (CHLs), particularly those that result from pathologies
not amenable to medical and surgical treatment
- Goal: increase magnitude of acoustic signal at output Vs. input
- Basic system has three components:

o Microphone : converts signal from acoustic to mechanical to electrical

o Amplifier : boosts electrical signal
o Receiver/ speaker : converts electrical back to acoustic signal

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- Three categories of devices currently on market

1. Nonprogrammable analogue devices

· Constant analysis and modification of input stimulus

2. Digitally programmable analogue systems

· Digital memory used to generate several different HA responses that can be
selected for different listening conditions
· Different processing strategies allow better electro-acoustic adjustments
and flexibility in adjusting gain and output

3. Digital signal processing (DSP) devices:

· Sound is represented as a string of numbers (analog-to-digital conversion)
· Sound is then manipulated by DSP using math formulae
· New string of numbers are converted back to sound (digital-to-analog
conversion)
· Smaller and cheaper to make than analogue counterparts
· Tailor output to individual loss
· Currently 50% of market;

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Riyadh et al. Notes
656
Gain: amplification; can be applied in linear or non-linear · (compressive or
expansive) fashion

· Types of Gain

o Linear: direct relationship between input and output

o Non-linear:
· Compressive decreases gain with increasing input intensity (good for those
with small range between functional hearing and discomfort i.e. narrow
“dynamic range”)
· Compression HA function as linear devices for sound intensities below
compression threshold (CP)
o High CP-limits max output level, while providing linear amplification for
most speech inputs
o Low CP-nonlinear amplification for most levels

· Expansive decreases gain for decreasing amplitude sounds (to reduce

background noise)

Another goal addressed by nonlinear amplification strategies is to make

speech and other important environmental sounds both audible and
comfortable

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Understanding speech in noise
x Most common cause of poor compliance
x Signal to noise ratio: difference between level of sound you want to
hear and that of background noise
x Pt with HL require higher Signal-to-Noise Ratio (SNR) to hear in noise

o Omnidirectional microphones do not improve SNR in comparison to the

unaided ear

o Directional microphones use multiple microphones ports to allow

SNR improvements based on spatial separation between signal and noise
ƒ Signal of interest-front hemisphere
ƒ Noise-rear hemisphere
ƒ Reduced effectiveness in reverberant (reflective) environments and
when the signal is located at a great distance
ƒ SNR improvement is 3-6 dB
ƒ Full-time directional HA is not recommended

x Acoustic feedback occurs when the amplified sound that emanates

from a receiver is directed back into the microphone of the same
amplifying system.
x Physical separation of the microphone and receiver is the most
effective way to reduce feedback
x Causes of feedback:
o Poor fit
o Over amplification
o EAC plugged
o Mic to close to speaker

Digital Signal Processing-Based Features

· Digital noise reduction (DNR) scheme: decrease gain · in ranges with no

detectable speech; detects speech based on amplitude modulations; shown
to improve comfort, but has no speech recognition benefit

· Digital feedback suppression (DFS) scheme: allow for increased gain under
constant coupling constraints (same HA shell and vent size); can be helpful
in those with occasional feedback, and to allow for a bigger vent to improve
sound quality of wearer’s voice

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Riyadh et al. Notes
658
Styles and Shapes of Hearing Aids

Behind-the-ear HA (BTE)
o Replaced body worn HA
o More cosmetic appeal; no body baffle effect (on torso-increased
low frequency amplification and decreased amplification in high
frequencies); no noise from clothes rubbing against microphone
o custom-fitted earmold, a standard coupler, or a receiver in the canal
o telecoil

In-the-ear (ITE)
o Benefit of normal acoustics provided by the pinna increased gain in the
high frequencies
o Pinna acoustics also important for sound localization cues
o smaller and fits into the ear canal is known as an in-the-canal (ITC)

Completely-in-the-canal
o It is even smaller and fits deeply in the canal
o Maximize pinna and concha effects high-freq gain and reduced occlusion
effect
o Fitting is difficult

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Riyadh et al. Notes
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660
Other styles:

Contralateral routing of signal (CROS)

o No usable hearing in 1 ear and normal hearing or a minimal HL in the other
ear
o Microphone is placed on the impaired side and
transmitted to the good ear via an open ear mold or a
polyethylene tube
o Disadvantages: user must be motivated to hear sounds
arriving at both sides equally (not natural), 2 devices, poor
sound quality, poor cosmetics

BiCROS
o No usable hearing in 1 ear and minimal HL in the other
ear
o Amplification to the better ear AND contralateral routing of signal from bad
ear

Transcranial CROS
o Single deep-fitting custom instrument to the impaired ear; allows
mechanical coupling between HA shell and bony portion of the EAC
transmission of sound to contralat cochlea through both AC and BC

Bone-conduction aid
o BC receiver is placed on the mastoid and held in position by headband
o More energy is required to stimulate the ear via BC-only useful for milder
SNHL
o More useful for CHL (traditional bone conducting hearing aid)

Bone-anchored HA (BAHA)
o HA transducer is coupled to titanium screw in upper mastoid region of TB
via a titanium abutment screw
o Indications: CHL, cannot use conventional HA, unilat SNHL

Middle ear implants

o Pure SNHL and mixed losses
o Piezoelectric, electromagnetic, electromechanical properties used to drive
an output transducer mounted on the ossicular chain

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661
Electroacoustic Characteristics of Hearing Aids

x Three most important are: gain; output sound pressure level with 90
dB input (OSLP90) ; frequency response
x Gain
o Difference in the output relative to input
o Full-on gain: amount of amplification with maximum volume
control setting
o High-frequency average (high-frequency full-on gain): gain
measured at 1000, 1600, 2500 Hz (recommended by ANSI)
o Reference test gain: amount of amplification when volume
control is adjusted such that the average gain at 1000, 1600,
and 2500 Hz is 17 dB below OSPL90 or full on if HA has mild
gain
o Use gain (as-worn gain): gain measurement with volume control
adjusted to its normal use position

x OSPL90
o Saturation sound pressure level
o Maximum amount of amplification provided by the instrument
o As input level increased, output level increases until a certain
point, above which further increases in input do not change
output saturation
o OSPL90: 90-dB input signal and output measured across freq
range

x Frequency response
o Gain of HA across a range of frequencies
o Range of frequency of gain is usually limited
o Frequency response: measure reference test gain, subtract 20
dB; line is drawn parallel to the abscissa until it intersects the
low and high frequency ends of the curve

Output Limiting

x TD = threshold of discomfort (aka LDL, or loudness discomfort level)

x Dynamic range of hearing: between level at which sound is barely
detectable, up to TD; can be small for SNHL
x OSPL90 should be set below TD
x Peak clipping: a way to limit output in linear systems; introduces
harmonic and intermodulation distortion as peaks are clipped;
compression is better

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662
Hearing Aid Candidacy

x Indication based on: degree and configuration of HL, communication

disorder, motivation of Pt and attitude toward HA
x Audiometry alone can’t tell you who will benefit; trial is essential
x Also consider motivation for aiding; acceptance of loss (they won’t
wear it if sent in by a spouse) and expectations
x Another audiometric indicator of hearing aid use is suprathreshold
speech-recognition ability
(If it is sufficiently poor, hearing aid amplification will contribute to audibility
but may not be satisfactory overall.)
x Success measured objectively and subjectively; reduction of handicap
x The majority of patients who choose to use hearing aids have hearing
loss that is at least moderate in degree.

x As a general rule, if the hearing impairment is enough to cause a

problem in communication, the patient is a candidate for hearing aids.
x If a patient has a sensorineural or other nontreatable hearing loss that
is causing a communication disorder, the patient is a candidate for
amplification

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Benefits of Bilateral Hearing or Amplification

1. Release from masking (AKA binaural squelch): improved speech

intelligibility due to phase differences of the signal and noise
occurring between the two ears
2. Sound localization better with binaural hearing
(Brain relies on differences in time and intensity of signals between the ears
to localize the source)
3. Eliminates head shadow effect
4. Binaural summation: sum; get louder sound & better amplification
5. Better sound quality

Unilateral hearing aid fitting places the unaided ear at a relative

disadvantage, which may have a long-term negative effect on the speech
perception ability of the unaided ear

Selecting Hearing Aids

x Must perform assessment of communication needs

x Can include: hearing thresholds and TD; middle ear function; EAC
shape, geometry and movement; speech recognition in quiet and in
noise; hearing aid expectations; perceived hearing handicap; specific
listening environments in which the patient has trouble

Verification

x Fitting and verification is a process, not an event

x Real ear insertion gain REIG: measured at TM with mold and aid in
place, rather than the 2 cm3 artificial test; good because it can account
for all factors (pinna, head diffraction and EAC resonance)
x Real ear aided response REAR: used in children
x Real ear coupler difference RECD: used in younger children
x Aided soundfield threshold measurements not good, because:
o Time consuming
o Poor frequency resolution
o Poor test-retest reliability
o Misleading information in case of severe/profound, or mild HL
x Orientation: teach them how to use and maintain it
x Validation: keep testing over time to make sure it’s working

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Problems with HA:
x Bad fitting
x Feedback
x Headaches and Tinnitus
x Improper sound level and quality
x Sweating and wax impaction
x Insertion loss: a certain amount of hearing loss occurs with occlusion
of the ear canal while the hearing aid is in place (for patients who have
normal low-frequency hearing)
x Occlusion effect: Occlusion of the ear canal also causes a
phenomenon wherein a patient’s own voice is perceived as loud and
echoing

One solution to occlusion problems is the placement of a vent, which is

simply a passageway for exchange of air and sound around or through a
hearing aid or earmold

Other hearing assisting devices:

Assistive Listening Devices

x Mild impairments
x Types of communication needs
o Interpersonal communication and media
o Telecommunications
o Signals such as wake-up alarms, fire alarms, telephones
x ALDs are for specific listening situations
o TV or radio amplifiers
o Flashing alarms
o Amplified telephone
x ALDs can help with speech in noise (improve the SNR in noise and
reverberations)

FM Wireless System

x Adv: acceptable SNR for speech understanding in noise (educational

environment for children)
x Talker wears a transmitter/ microphone around the neck; frequency-
modulated signal is broadcast to an FM receiver unit worn by the
listener
x External receivers are typically coupled to ear molds, earphones
x Coupling of FM system to personal HA
o Electrical coupling
o Inductive loop arrangement

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Soundfield Systems

x Speech signal is delivered through a loudspeaker placed strategically

in the classrooms

Infrared Systems “Signal transmission via infrared light”

x Acoustic signal is converted to electric signal; infrared transmitter

modulates it into infrared light frequencies emitted from radiators
x Several light-emitting radiators are placed throughout the room

Other Assistive Listening Devices

x Telephone amplifiers (telecoil or telephone amplifiers)

x Television/radio amplifiers
x Signaling devices (high-intensity door bell)
o Alerting devices visual (strobes, bright lights); tactile (vibration,
airstream)

Training

x Speech reading
x Auditory training
x Speech conservation
x Sign language

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LIMITATIONS OF AUDITORY REHABILITATION USING TRADITIONAL
HEARING AIDS

PHYSICAL FACTORS
Limited in their ability to amplify sound without imparting distortion or
generating feedback

x Insufficient Gain
x Acoustic Feedback
o Worst for CIC aids, and for ears with mastoid bowls, in which an air
seal is difficult to obtain or whenvery high amplification
o Fitting hearing aids tightly into the external auditory canal can
decrease feedback but at the cost of increased discomfort and at the
risk of otitis externa, autophony, and blockage of natural sound input

x Distortion of Spectral Shape and Phase Shifts

o HA are limited in the frequency range over which they amplify sound in
the speech band (500 to 2000 Hz)
o Isolated severe hearing loss at low frequencies, as in Meniere disease,
or at high frequencies, as in presbycusis or ototoxic exposure, can be
difficult to remediate with traditional aids without overamplifying the
midrange frequencies
o Digital signal processing technology has greatly improved spectral
shaping options compared with analog aids, but these fundamental
limitations persist.

x Nonlinear Distortion
o Hearing aids are designed under the assumption of linearity—that is, if
a given sound input at the microphone leads to some output at the
speaker
o For high-intensity speaker output, this assumption breaks down as the
speaker is driven into the range of movements for which it begins to
saturate orclip.
o An input sinusoid can appear at the output as a waveform with blunted
peaks.
o This nonlinear distortion imparts aberrant spectral components into the
sound percept, giving it an artificial or robotic character.
o Whereas digital signal processing can mitigate distortion effects,
remains a fundamental limitation of traditional hearing aids.

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x Occlusion Effects
o To minimize feedback
o Canal occlusion has several undesirable effects:
1) it can be uncomfortable because of pressure on canal skin
2) it increases the likelihood of otitis externa as a result of disturbance
of wax egress and air circulation, and some patients with chronic
suppurative otitis media cannot tolerate hearing aids because of
exacerbation of otorrhea
3) it causes autophony and a sense of aural fullness that can worsen
with changes in ambient barometric pressure
4) it blocks the normal pathway for sound entry to the ear
5) it disrupts the spectral shaping that normally occurs as a result of
external auditory canal resonances

x Poor Appearance
x Poor Transduction Efficiency
o Loss of energy as a result of impedance mismatching and transduction
o Impedance-matching transformer by virtue of the relative areas of the
tympanic membrane and stapes footplate and by the lever action of
the ossicular chain
o When this middle ear apparatus is malfunctioning—as occurs in
otosclerosis, tympanic membrane perforation, or a CWD
mastoidectomy— traditional hearing aids must overcome the
impedance mismatch.
o The result is either reduced effective gain or increased distortion, or
both

HUMAN FACTORS

x Recruitment and Compression of Dynamic Range

x Disordered Perception of Pitch and Sound Localization

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THE PROMISE OF IMPLANTABLE HEARING DEVICES

Implantable hearing devices offer the patient with hearing loss several
potential advantages over conventional hearing aids. These include
x Increased gain and dynamic range
x Reduced feedback and destortion
x Improved sound quality
x Better directional hearing
x Reduced maintenance
x Improved appearance
x Freedom from ear canal occlusion

Downsides of their use, which include

x Risk of surgical implantation
x Difficulty of maintenance
x Increased initial device cost

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OSSEOINTEGRATED BONECONDUCTING HEARING PROSTHESES

x Titanium had a unique ability to become firmly anchored in bone

x Back ground: was initially applied to dental implants, then to provide
an anchor for facial prosthetics (pinna, eye, or nose) and an
attachment for a bone-anchored hearing device
x Indicated in: CHL, MHL and unilateral SNHL (as in CROS)

Criteria for CHL or MHL

• A minimum average bone conduction threshold of 45-dB HL or 55-dB HL

• For bilateral fitting, symmetric bone conduction thresholds are
recommended
• The BAHA Cordelle II body worn device is recommended for severe mixed
hearing losses, but the average bone conduction thresholds of the implanted
ear should be less than 65-dB HL

x Pt with CHL or mix not suitable surgical candidates for correction of

there disease (otosclerosis, tmpanosclerosis, canal atresea…etc)
x Unable to tolerate a conventional hearing aid (discomfort from sound,
large mastoid, meatoplasty, discharging ear, canal closure like in blind
sack or extensive base of skull surgery)

Criteria for unilateral SNHL

• Profound hearing loss in the implanted ear

• Hearing in the contralateral ear is better than or equal to 20-dB HL

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OSSEOINTEGRATION: BIOLOGY AND HISTOLOGY

- Direct contact must be made between the bone matrix and the
implant
- No interposed fibrous or soft tissue
- No evidence of inflammation should be present at the implantation
site (includes infiltrates or osteolysis)
- No evidence of a connective tissue capsule on the implant surface

RADIOLOGIC IMPLICATIONS

x A chief disadvantage of any metallic implant is interference with

subsequent radiologic studies
x IN BAHA This scatter effect has relatively little impact on the quality of
CT images produced.
x MRI is not contraindicated with the presence of a titanium implant.
x Any attached components must be removed prior to the scan

BAHA components:

(a) Titanium fixture (implant)

(b) Titanium abutment

(c) Sound processor

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OPERATIVE TECHNIQUE

x In adult now done as single stage

x In children done in 2 stages (6 months interval) give time for
integration
x Implant must be performed meticulously and as gently as possible to
minimize thermal damage to surrounding bone
x The skin penetrated by the implant must be hairless to facilitate
keeping the implant site clean
x Subcutaneous tissue should be aggressively thinned to minimize skin
mobility in relation to the implant
x Place the device 50-60mm from the ear canal
x Drill a whole in mastoid 3-4mm
x At the end place a healing cap onto the abutment
x Sound processor is loaded after 12 weeks (in pediatric post single
stage place the processor 16 weeks)

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BAHA IN YOUNG CHILDREN
x Baha recommends the osseointegration procedure in children over the
age of 5 years.
x For children under the age of 5 years in need of bone-conduction
hearing, the Baha Softband is available
x Higher incidence of nonintegration (avoided by 2 stage surgery)

x New studies showed even better results with staged surgery in <5
years old

COMPLICATIONS

x Soft tissue reaction

o Skin overgrowing the abutment (most common complication)
o Redness
o Infection
o Necrosis
o Moister

Avoided by extensive intraoperative soft tissue reduction. Also, the skin can
be tacked down to the periosteal layer to immobilize this region.

x Osseointegration failure (second most common complication)

x Need for revision surgery

BAHA RESULTS

Recommended that to be in consideration for a “high success rate” with the

Baha, patients should have a PTA below 45 dB

BAHA FOR UNILATERAL SENSORINEURAL HEARING LOSS

Compared to CROS:
x Sound localization poor in both
x BAHA has better speech recognition
x BAHA has better amplification
x BAHA has better hearing in noise

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Alternatives to BAHA

Transcutaneous Bone-Anchored Hearing Devices

x Created to avoid the complications of having a percutaneous abutment
x Instead The implant is magnetically coupled to the external oscillator
and transmits vibrations to the skull
x Same indications as BAHA

1. Alpha 2

2. Bonebridge (Med-El)

Dental Appliance–Based Bone-Conduction System

x The Sound-Bite
x Uses a BTE receiver and sound processor that sends signals to a
custom-made, removable, in-the-mouth piezoelectric transducer
coupled to the buccal surface of the maxillary molars

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MIDDLE EAR IMPLANTS

x 2 types of transducers available

o Piezoelectric
o Electromagnetic

x 2 types of implant:
o Partial
- external microphone and speech processor
- transmitter with an external coil that transmits electric energy
transcutaneously
- internal device

o Total
- house all of the abovementioned internally (including the battery
pack).
- Slightly larger in size and complexity, but less visible (all under)
- require reoperation at approximately 5-year intervals to exchange the
battery

x must adapt to the mechanics of the middle ear and ossicular chain
x Couple to one of the three middle ear bones in one of a number of
ways to directly drive the ossicular chain.
x Convert the electric signal into mechanical energy that is then coupled
directly to the ossicular chain
x Some designs will also couple directly to the oval or round window.

The Classical indication to MEI is mild-to-moderate sensorineural hearing loss

with intact speech discrimination abilities

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ELECTROMAGNETIC MIDDLE EAR IMPLANTABLE HEARING
DEVICES

VIBRANT SOUNDBRIDGE (MED-EL)

Indicated in:
- Moderate to sever SNHL
- CHL and MHL (when placed in oval or round window or even
on ossicle prosthesis “Vibroplasty”)

Components:
x Implantable component (internal receiver and processor)
x Vibrating ossicular prosthesis (VORP) typically attach to log process of
incus
x Floating mass transducer (FMT)
x External microphone and receiver (similar to HA)

- Implanted by standerd trnsmastoid facial recess approach

- Only need to be near the ossicles (not directly attached)
- The ferromagnetic device attached to the ossicles will transmit the
auditory signal to the ossicles.
- The VORP is crimped into the long process of the incus
- The internal receiver is placed in a bony trough in the retrosigmoid
bone

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- Because of the confined space between the eardrum and the incus, the
dimensions and mass of the FMT are limited, which restricts its output.
- Drawback is erosion of the incus long process because of ischemia at
the clip attachment site
- FMT includes a magnetic component, implantation of this device
prevents a patient from undergoing magnetic resonance imaging (MRI)
without device remova

- Other than incus: stapes, oval window, round window, prosthesis or

piston

PIEZOELECTRIC MIDDLE EAR IMPLANTABLE HEARING DEVICES

x Function by connecting the ossicles directly to an amplifier using a
piezoelectric crystal vibrator.
x Piezoelectric materials are dielectric materials with coupled electric and
mechanical properties
x Larger than electromagnetic devices
x Advantage of this type of transducer is its ability to deliver more
distortion-free amplification directly to the ossicular chain

x Attach to body of incus body (carina)

x Attach to mallius and stapes head (Esteem from envoy)

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CARINA
x Fully implanted
x No external component
x Implanted through atticotomy and a hole in
body of incuse (laser)
x Has battery that is chargeable

Variations on the size and length of the ossicular coupling have expanded the
application of the Carina to patients with aural atresia and ossicular
discontinuity via direct attachment of the device on the stapes capitulum,
stapes footplate, and round window

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ESTEEM

x Fully implantable
x Designed for mild to severe HL
x A piezoelectric bimorph placed on the malleus head can effectively
use the tympanic membrane as a microphone
x Uses a piezoelectric crystal to convert malleus vibrations, the result of
sound waves impinging on the tympanic membrane, into a voltage
encoding sound.
x Requires partial removal of the incus to prevent feedback from the
actuator to the sensor. (This results in a maximal CHL)
x Then output transducer, which converts the applied voltage to
mechanical vibration coupled to the stapes
x Battery designed to last for 5 years (non chargeable)

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Complications of MEI

Complications from transmastoid and facial recess drilling.

Specifically, most devices require a large recess => chorda tympani injury

Others:
x Skin breakdown
x Postoperative infection
x Extrusion
x Improper device placement
x Inadequate hearing benefit.
x Inadvertent activation with various electromagnetic fields such as a
microwave
x Device failure

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COCHLEAR IMPLANTS

x A device designed to convert environmental sound into electrical

impulses that are delivered along a multiple electrode array situated in
close proximity to the cochlear (auditory) nerve
x It has been reserved for patients with significant degrees of hearing
loss that are not easily rehabilitated with conventional amplification

Cochlear Implant Systems

x Essential components:
x External device (microphone, speech processor, headpiece)
x Internal implanted device (receiver -stimulator, multichannel electrode
array)

o Microphone: convert acoustic to electrical energy

o External speech processor: processes signal (convert it to
digital electric signal); processing of the electric signal involves:
x Filtering; to separate the information into discrete freq.
band that are deliverd to the appropriate regions of the
cochlea to provide spectrai information about the speech
signal
x Amplification
x Compression; the information must be compressed to fit
the narrow dynamic range of electric stimulation (It is
necessary to map the wide dynamic range of the normal
acoustic environment onto the limited dynamic range of
electrical stimulation)
o Transmitter
o Implanted receiver-stimulator: decode the signals and sends
it to electrode array
o Electrode array: implanted in the cochlea; delivers signal

x Spiral ganglion cells or axons are stimulated directly; damaged or

missing hair cells are bypassed with a cochlear implant system
x Multielectrode systems are designed to take advantage of the
tonotopic organization of the cochlea

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x Nucleus 24 cochlear implant system
o Made by Cochlear corporation (also make Nucleus 22)
o 22 intracochlear electrodes; 2 extracochlear ground electrodes
o Three programming strategies: SPEAK; ACE and CIS

x Clarion or (HiRes 90K) cochlear implant system

(Advanced Bionics corporation)
o HiRes Bionic Ear is the newest of their models
o 16 intracochlear electrodes
o Can use continuous (CIS) programming strategy, or a variety of
other combinations

x C40+ cochlear implant system/ Sonata

o Med-El corporation
o Combi 40+ system (C40+)
o 12 electrode pairs; can be inserted deep into apical region

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Pathologic Basis for Success

Cochlear implantation usually results in a loss of residual acoustic hearing,

presumably from:
¾ intracochlear trauma induced through cochleostomy or electrode
insertion
¾ disruption of the endocochlear potential
¾ or delayed reaction to the foreign body.

x Trauma and bone dust may also induce further changes in the inner
ear including fibrosis and osteoneogenesis.
x These changes might also reduce future abilities to reimplant the
cochlea or the patients to consider other biologic therapies

Patient Selection

Patient’s history followed by a physical examination.

Otologic history includes
x Onset and progression of hearing loss
x Etiology of hearing loss
x History of amplification use (recommendation use at least 3 months
pre-implant)
x History of meningitis
x Ear infections—past/current
x Previous otolgic surgeries

Exam
Active infection
Perforations
Tympanostomy tubes

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Absolute contraindications to cochlear implantation include
those patients without either a cochlea (Michel aplasia) or a cochlear nerve.

Relative contraindication might include

x Active middle ear disease
x severe anesthetic risk
x too much residual hearing
x those who are unwilling to tolerate the surgical risks.

Preexisting mastoid cavity must be either obliterated with blind-sac closure,

or the post canal wall must be rebuilt

There are clearly patients who may require adjustment of expectations

through
(a) cochlear disorders such as extensive cochlear obstruction from
previous meningitis, otosclerosis, or inner ear malformation
(b)auditory neuropathy / desynchronize (50%)
(c) CNS dysorders (stroke, dementia, MS, infection, tumor)

Candidacy
¾ Adults
(>=18 years) are required to have bil moderate-to-profound hearing loss
without medical contraindications and the desire to be a part of the hearing
world. And low aided speech perception

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686
¾ Prelingual children

Can be as young as 12 months of age (FDA), with bil profound HL gain

limited benefit from amplification, while being enrolled in an early
intervention program.
acquire speech and language through central plasticity that results from
stimulation by auditory prostheses.
¾ Earlier implantation has risk of:
x None accurate diagnostic test (most accurate after 6 months)
x Anatomical challenges (temporal thickness, mastoid development,
facial nerve)
x Risk of bleeding (blood volume, immature mastoid bone bleed)
x Difficult language development with HA or after implant

¾ Clear indication of early implant:

x After meningitis or temporal or cochlea trauma (before ossification)
x In blind child

Older children with some degree of speech perception should also have
specific speech perception
testing results that are obtained while wearing appropriate amplification

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x Audiologic assessment
Adults
o Unaided and aided thresholds for pure tones
o Minimum Speech Test Battery (MSTB)
o Used at many cochlear implant centers to assess pre and postimplant
o performance
o Set of compact disc recordings for standardization
o Includes the following:
¾ Consonant-Nucleus-Consonant (CNC) Monosyllable Word Test
¾ Arizona Biomedical (AzBio) Sentences (in quiet and in noise)
¾ Bamford-Kowal-Bench Sentences in Noise (BKB-SIN)
¾ hearing in noise test (HINT) sentences were previously part of the
MSTB but have fallen out of favor due to ceiling effect

Children
o ABR and OAEs
o Implant candidates typically have no response at limits of the
o testing equipment
o Findings/implications in auditory neuropathy (-ve ABR/+ve OAE)
o Unaided and aided thresholds for pure tones
o Speech perception tests

o Meaningful Auditory Integration Scale (MAIS)

questionnaire for family of children too young to participate in speech
perception tests

o Early Speech Perception (ESP) Test

word is spoken without visual cues, patient selects correct object or
picture of the stimulus

o Lexical Neighborhood Test (LNT), multisyllabic LNT (MLNT)

LNT—50 monosyllabic words, ranging from “easy” (high frequency, few
lexical neighbors) to “hard” (low frequency, many lexical neighbors)

MLNT 2-3 syllable words; open-set test; MLNT 2-3 syllable words;
open-set test

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Pre op imaging

Imaging of the temporal bone and brain:

(a) identify the etiology of hearing loss
(b)define surgical anatomy and the potential for complications or squeal
(c) identify factors that negatively impact upon prognosis for performance
using the device.

Pre-op CT Scans
1. Location of large mastoid emissary veins
2. Height of jugular bulb
3. Thickness of parietal bone
4. CNS disorders
5. IAC
6. Inner ear morphology
7. Cochlear patency (calcified)
8. Position of fallopian canal
9. Size of facial recess

Pre-op MRI
o Consider in cases of possible ossification or when CT shows IAC
< 3 mm diameter to demonstrate a cochlear nerve
o cochlear patency (fibrosis)

(Hypoplastic cochlear nerve can be checked with Ecog intra-op)

x Psychological assessment
o Family dynamics, support structure and motivation assessed
o Must rule-out early psychosis and MR

Vaccination

x Pediatric and adult patients with cochlear implants are at increased

risk of acquiring S. pneumoniae meningitis
x Note:
o Prevnar pneumococcal 7-valent conjugate (conjugated) ears

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Surgery for Cochlear Implantation

Ear Selection
x Physical characteristics
o Presence of cochlea and auditory nerve, degree of dysplasia,
degree of ossification, prior surgical procedures, CN 7
anomalies, chronic OM
x Residual hearing level
o Worse ear favoured if opposite ear can be aided
o Also consider duration of deafness (if >10-15 yrs, implant better
hearing ear)

Clear middle ear space should be confirmed through:

Otoscopy, tympanometry, and/or temporal bone imaging

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Riyadh et al. Notes
691
¾ Perioperative antibiotics are given 30 minutes before skin incision.
(A first-generation cephalosporin)
¾ GA
¾ Facial monitoring
¾ local anesthetic with vasoconstrictor is infiltrated post auricular area
¾ lazy S incision (don’t go lower than mid of pinna => superficial facial
nerve)
¾ cortical mastoid and facial recess approach opend maximally

very important to recognize that limited opening of the facial recess

can result in an inferior view towards the hypotympanum with a
resulting look at the air cell system rather than the promontory and
round window region.

¾ The round window niche overhang is initially identified (located 1-2mm

inferior to the oval window niche and anterior-inferior to the stapedius
tendon.
¾ niche overhang is removed to expose the round window membrane,
the primary landmark to scala tympani.

Alternately Cochleostomy placed anteroinferior to round window

¾ position of the receiver stimulator usually is significantly superior and

posterior to the pinna (subperiosteal pocket is created)
¾ A bony depression can be created according to the device templates
¾ Open the round window membrane
¾ A smooth, resistance-free insertion of the proposed electrode array in
to patent scala tympani is the goal of most implantations.
¾ Fascia or muscle place around opening for sealing

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Neural response telemetry “NRT”

x Performed during the CI surgery and at the follow-up appointments as

needed
x Gives confirmation that the CI is effectively stimulating the hearing
nerve fibres in the inner ear
x NRT measurements assist in selecting and optimizing initial
programming parameters — speeding and simplifying the
programming of young children

o electrode impedances (detect open circuit)

o electrically evoked compound action potentials.

Special Surgical Considerations

For inner ear anomaly and chronic ear (go to specific chapters)

1- Inner Ear Obstruction

o inner ear inflammation from meningitis
o immune-mediated ear disease
o otitis media with labyrinthitis
o sever otosclerosis
o trauma.

cochlear lumen can be narrowed or obliterated with fibrous tissue or bone.

Preoperative imaging with MRI and cT will usually reveal the extent to which
such obstruction exists and the approach needed for implantation.
In cases of ongoing meningitis, intervention should be considered in the early
stages so as to avoid total obstruction
Bilateral implant in initial surgery

1600
Riyadh et al. Notes
694

x In cases of short segment obstruction resulting from either fibrosis or

bone (1 to 3 mm), a typical round window-related cochleostomy can
be created by drilling through the short segment of obstruction.
x Array insertion can usually proceed in a normal fashion.

x If more than 3 mm of drilling fails to reveal a patent cochlear lumen, a

scala vestibuli insertion should be considered by moving superiorly,
above and anterior to the round window

x An apical cochleostomy is also created for an upper retrograde

insertion.
x This opening is made anterior to the oval window inferior to the
cochleariform process.
x communication with the individual programming the device is critical
to insure that proper pitch assignment is made for the retrograde
electrodes.

Ossifican can happen post meningitis as early as few moths

And can happen after 10 years of infection

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695
2- Otitis Media

x Active otitis media is a contraindication to cochlear implantation

x Can result in suppurative labyrinthitis with subsequent meningitis and
ossification.
x Device colonization can result in subsequent wound infection,
breakdown, and hardware loss
x In cases of acute otitis media, delayed intervention is justified.
x If recurrent disease is probable. tympanostomy tube insertion is
reasonable with delayed implantation.

x There are some advocates for subtotal petrousectomy with blind sac
closure in the setting of otitis media to avoid future considerations for
this problem.

x In cases of serous effusion. the incidence of bacterial colonization is

probably very low.

x But in cases of mucoid effusion, delayed intervention is wise.

Pre op OME => place a VT

Intra op found OME can proceed with some difficulty intra-op
Intra op VT => can be removed if no longer needed but if left in place no
harm
Post implant OME => can be treated with VT or leave it

Cochlear implantation is associated with neither increased incidence of otitis

media nor complications such as labyrinthitis

Post-op follow up
x Mastoid X-ray first day post-op
x Tests of performance:
o MSTB (Minimum Speech Test Battery)
ƒ Standardized set of comprehensive tests of pre-
and post-op speech recognition
ƒ Components
x HINT (Hearing In Noise Test)
x CNC (consonant/nucleus/consonant test)

x Follow up with audiologist for programming

o At least q/1 yr for adults
o At least q/6 mo for kids
o Also need post-implant rehab (to improve perception and
language skills)

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Riyadh et al. Notes
696
Complications

x Hard failures result from internal, receiver-stimulator problems and

require revision surgery
x Soft failure despite the presence of auditory percepts, the patient
experiences aversive symptoms such as pain, shocking. atypical
tinnitus, or a decrement in function, device changed only after
confirming location in imaging and changing external device showed
no benefit
x With surgical advancements, these issues have become decidedly rare.
x Minimal approaches to skin incisions and proper device location and
immobilization have been key in reducing such complications.

Other complications include

x taste disturbance from chorda tympani nerve manipulation or sacrifice
(-10%)
x transient dizziness (-10% of adults and less common in children)
x complete vestibular deficit is uncommon
x subcutaneous seroma (10%) (resolve spontaneous)

1603
Riyadh et al. Notes
697
Meningitis in Cochlear Implant Recipients

The incidence of meningitis in cochlear implant recipients is greater than that

of an age-matched cohort in the general population
Though overall rate is low (<0.6%)
Risk factors in this population include
x young age
x the presence of inner ear malformations
x the use of a two-part electrode system.

The risk of meningitis also appears to be higher among individuals with

sensorineural hearing loss without a cochlear implant although this risk
appears lower than that of implanted

The most common organism identified in postimplantation meningitis is S.

pneumoniae.
All potential routes of spread (middle ear, inner ear, hematogenous) should
be considered in such a patient.
Precautions:

x create a relatively atraumatic cochlear opening, insert the electrode

array without trauma
x adequate seal at the cochleostomy with connective tissue
x pneumococcal vaccination in implanted is recommendation by the FDA
and implant manufacturers
x Early and adequate treatment of otitis media

1604
Riyadh et al. Notes
698
Results

Some of the factors that should be considered include

¾ Age
¾ age of onset of hearing loss (deafness)
¾ duration of deafness
¾ medical comorbidities,
¾ etiology of deafness
¾ residual hearing
¾ anatomic cochlear and cochlear nerve status
¾ cognitive abilities, behavioral condition
¾ psychological factors
¾ parental desires and involvement
¾ educational setting and training

x Very wide range of results; very patient dependent

x Most important factor is duration of deafness; longer = poorer results
x Speech recognition remains the standard metric of cochlear implant
candidacy and performance
x Adult:
o Depends on age at implantation and duration of deafness
o Average post-op sound field detection thresholds for warble-
tone stimuli are approximately 25 to 30 dB HL for frequencies
between 250 and 4000 Hz
x Children:
o Spoken word recognition
ƒ Similar to adults but continual development of speech
perception and spoken word recognition abilities over a
long time course
ƒ In children, initial reports suggested that implantation
before the age of 3 years provides distinct advantages
over later implantation in cases of early-onset deafness.
ƒ More recent data suggest that speech recognition and
language skills are facilitated with implantation in earlier
toddler and infancy stages.
ƒ Outcomes related to educational success, quality-of-life
impact, and cost effectiveness after early cochlear
implantation generally relate to a child’s ability to acquire
oral language as a result of auditory sensitivity and
enhanced speech recognition.

1605
Riyadh et al. Notes
699
x Screening for other handicapping conditions, particularly conditions
that would impair the acquisition of receptive and productive
communication skills, helps determine candidacy and directs
rehabilitative strategies.
x In the absence of handicapping conditions, a generic analysis of the
literature on cochlear implant outcomes yields the conclusion that
more than 85% of implant recipients are able to use their device to
gain meaningful engagement with the hearing world.
x Postimplantation rehabilitation can be important for some adult
implant recipients, but it is crucial for children to optimize the
usefulness of an implant.

o Speech production and language outcomes

ƒ Variable results but can reach their peers level

¾ Finally, cochlear implants are being placed in patients with

progressively greater degrees of residual hearing using special
electrode arrays and surgical techniques that allow for preservation of
residual acoustic hearing.
¾ The combination of electric and acoustic stimulation in the same ear
(electro acoustic stimulation or hybrid implantation

1606
Riyadh et al. Notes
700

With the benefits of binaural hearing increasingly being recognized,

candidacy decisions now include bilateral implantation, cochlear implantation
for single-sided deafness, and implantation of ears with low-frequency
hearing with hearing preservation.

Revision CI
Non–Device-Related Indications
x Infections
x Cholesteatoma
(remove the cholesteatoma remove the disease and cut the electrode in
the cochlea, reimplant in second look with blind sac)
x Allergic reactions
x Extracochlear electrodes (most common after device related)

Device-Related Indications
x most common cause of reimplantation
x Facial nerve stimulation
x Device failure (hard or soft)

1607
Riyadh et al. Notes
701
AUDITORY CNS IMPLANTS (Auditory Brainstem Implant)

x convert environmental sound into electrical impulses that are delivered

along a multiple electrode array situated in close proximity to the
cochlear nucleus in the brainstem.
x The ABI is indicated for patients in whom the cochlear nerve is absent
or unavailable for stimulation bilaterally.

(Most commonly, patients with hearing loss secondary to neurofibromatosis

type II with bilateral acoustic tumors)

Principles of Electric Stimulation of the Auditory System and Coding

Strategy

x ABI was developed from the cochlear implant; the basic tenants of
stimulation are similar
x The tonotopic arrangement of the cochlear nucleus. however, is
somewhat more complex and less accessible
¾ cochlear nerve fibers transmitting low-frequency sounds project
mainly to the ventral portion of the cochlear nucleus
¾ while basal cochlear nerve fiber transmitting high-frequency sounds
project to the dorsal portions of each nuclear subdivision

1608
Riyadh et al. Notes
702
Indications:

Profound hearing loss and no available cochlear nerve to stimulate bilaterally.

Designed for the purposes of helping patients with neurofibromatosis type II

this remains the most common indication and the only FDA-approved.

There remain a number of other clinical scenarios that might be amenable to

ABI, and these include
¾ Congenital cochlear nerve aplasia.
¾ bilateral temporal bone fracture with cochlear nerve disruption
¾ severe inner ear malformation (cochlear aplasia, internal auditory
canal aplasia)
¾ dense ossification secondary to previous meningitis or advanced
otosclerosis

In these cases, cochlear nerve integrity might be uncler and a trial of

cochlear implantation might be justified prior to undertaking an ABI
operation

Surgery

™ Approach
generally carried out through a posterior fossa craniotomy-either
¾ translabyrinthine
Or
¾ rettosigmoid.

distinct advantages of the translabyrinthine approach for ABI are

(a) incision location that is more natural for receiver-stimulator placement.
(b) a lack of cerebellar retraction
(c) direct line of site to the lateral recess of the 4th ventricle afforded by the
presigmoid exposure
(d) electrode path through the immobile temporal bone rather against the
pulsatile cerebellar hemisphere

However, it is limited in some cases by a high jugular bulb, making lower

cranial nerve and recess visualization somewhat more tangential and difficult
at times

1609
Riyadh et al. Notes
703
™ Cranial nerve monitoring
Should include facial muscle electrodes, as well as palatal and trapezius
electrodes to monitor cranial nerves 9, 10, and 11.

™ ABR monitoring electrodes

critical for appropriate device placement

™ The receiver-stimulator should be placed in a region similar to the

cochlear implant. in a subperiosteal pocket Given

™ The lateral recess of the fourth ventricle (i.e., foramen of Luschka)

is the target for device placement.
Landmarks include the 8th and 9th cranial nerve root entry zones
x 8th superior boarder of recess
x 9th inferior boarders of the recess

™ A postoperative CT also confirms array location

1610
Riyadh et al. Notes
704
Complications:

Most complications described in these patients result from the posterior

fossa surgery indicated for removing the patient's acoustic neuroma rather
than from the device placement.
Include
x bleeding.
x Infection
x facial nerve injury
x loss of residual hearing

x CSF leakage (along the electrode carrier is more common among ABI
patients than typical acoustic tumor patients)

x Electrode dislodgment or difficult to find the recess

x Experience non auditory sensation (tingling, dizziness, jittering of eye,
choking, pain, vertigo, facial twitching, and potential changes in heart
rate, blood pressure, and respiratory efforts
x Stroke
x transient dysphonia aspiration related to lower cranial nerve
dysfunction.
x death.

Results:

x Wide range of results

x The ABI often provides environmental sound awareness and acts as an
aid to lip reading
x however, open-set speech perception can be achieved

x Better speech-perception outcomes have been demonstrated in non

tumorous NF2 (non-NF2) recipients with conditions such as
postmeningitic ossification or traumatic auditory nerve avulsion.

1611
Riyadh et al. Notes

705
Cochlear Implantation in Chronic Ear

x Cochlear implant are Auditory neural stimulators for patients with

preserved auditory nerve populations and are usually placed longitudinally
within the cochlear lumen, in Close proximity to the distal nerve fibers.
x Through auditory electrical stimulation, these devices have allowed
patients with congenital and acquired deafness to obtain sound awareness
and enhanced speech understanding in both quiet and noise, thereby
drastically improving educational and employment opportunities, social
integration, and overall quality of life.

Absolute contraindications to CI

• Without either a cochlea (Michel aplasia) or cochlear nerve.

Relative contraindication might include those patients with

• Active middle ear disease,

• Severe aesthetic risk
• Too much residual hearing

Cochlear implantation in a chronic diseased ear may lead to

• Implant colonization and subsequent implant extrusion

• Meningitis as a consequence of inserting an electrode through an infected
mastoid or middle ear cavity into a space with intracranial communication.

The degree of the activity of the disease has influence on the cochlear implant
strategy in patients with a chronic diseased ear.

COM can be distinguished on clinical and radiological characteristics into

• Active (with or without cholesteatoma)

• Inactive form

1612
Riyadh et al. Notes

706

Inactive form either

1. Simple dry perforation

2. A pre-existing radical mastoid cavity without Hx of active disease for
6/12

1613
Riyadh et al. Notes

707
1- Inactive form with a simple dry perforation, placement of the cochlear implant

and closing of the dry tympanic membrane perforation can be performed as a

single stage procedure

2- In patients having a pre-existing radical mastoid cavity without evidence for

an active inflammation, cochlear implantation is performed with a subtotal
petrosectomy (Blind Sac) as a single stage procedure

Reports on complications which required surgical treatment after CI in patients with

a stable COM are rare although some cases can be found

The complications include:

• Recurrence of cholesteatoma
• Explantation of the implant due to severe inflammation
• Wound breakdown
• Retraction pocket exposing the electrode array
•Extrusion of the implant side due to flap difficulties
All of these cases were reported as a consequence of flaring up of the infection
which all required subsequent surgical treatment

Interestingly, all complications occurred after either single-staged or staged

procedures

In case of an active infection (with or without cholesteatoma) Either:

With pre-existing radical mastoid cavity with active •
disease
Non–operated with active disease •
In all patients with COM the main issues of concerns are:

• Recurrence of a cholesteatoma
• Flaring-up of the infection

The options for active disease are mainly staged procedure either

• Combined approach tympanotomy with posterior tympanotomy followed

by CI in 3-6 months
• Subtotal petrosectomy (blind sac procedure ) followed by CI in 3-6 months
• Middle cranial fossa approach (to bypass the infected medium)

1614
Riyadh et al. Notes

708
Subtotal petrosectomy (blind sac procedure):

• Complete exenteration of all accessible air-cell of the temporal bone

• Sealing the Eustachian tube orifice
• Closure of the external meatus (blind sac)
This may be followed by obliteration of the tympanomastoid cleft with a pedicled
temporalis flap or with abdominal fat

Drawbacks:
• Risk of cholesteatoma recurrence if epithelial cells were left behind which
may lead to asymptomatic destruction (need to take utmost care)
• Mucocele may developed (if not all mucosa removed although its rare)
• Difficulty to facilitate radiological imaging and a second look to detect a
recurrent cholesteatoma (To overcome this issue the tympanomastoid
cavity can be left open)

Middle fossa approach

x Access to the cochlea bypassing the possible infected conventional route

for cochlear implantation
x The electrode is inserted through a basal turn cochleostomy created in the
floor of the middle cranial fossa

The possible drawbacks of this procedure are

• Risks of a craniotomy and compression of the temporal lobe

• Vascular injuries
• Facial nerve injury

1615
Riyadh et al. Notes

709
Cochlear Implantation in Inner Ear Malformations
• Inner ear malformations constitute about 20% of congenital sensorineural
hearing loss.
• At the beginning of the cochlear implant (CI) era, inner ear malformations
were regarded as a contraindication to surgery.
• In the present day, CI surgery in inner ear malformations is accepted as a
standard surgical approach.
• There are two major surgical problems in CI surgery in this patient
population:
1. Cerebrospinal fluid (CSF) gusher and meningitis
2. Facial nerve anomalies

ƒ Classification of cochlear malformations

ƒ Jackler et al. (1987) made the first classification of inner ear malformations.
ƒ They separated the anomalies into five groups:
1. Michel deformity (labyrinthine aplasia)
2. Cochlear aplasia
3. Common cavity
4. Cochlear hypoplasia
5. Incomplete partition (IP)

ƒ Sennaroglu and Saatci (2002) later defined the radiological features of two
completely different types of IP anomalies of the cochlea, as IP-I and IP-II
ƒ Recently X-linked deafness has been recognized as a third type of IP, IP-III

Normal cochlea

ƒ The most important section to determine the normal

cochlear architecture and IP anomalies is the
midmodiolar section (Figure 1A)
ƒ Midmodiolar view demonstrates the modiolus as a
quadrangular or pentagonal structure in the centre of the
basal turn.
ƒ Interscalar septa are thicker partitions between the inner
wall of the cochlea and the modiolus, which appear to separate the normal
cochlea into 2.5 (or 2.75) turns; the basal, middle and apical turns
ƒ The cochlear aperture (or cribriform area) is the central bony defect at the
base of the modiolus transmitting the cochlear nerve and blood vessels.

1616
Riyadh et al. Notes

710
ƒ A section inferior to the midmodiolar view,
passing through the area of the round window
niche (Figure 1B), shows the basal, middle and
apical cochlear turns.
ƒ The basal turn is in continuity at this section.
ƒ It is important to see the interscalar septum
between the middle and apical turns.

Cochlear malformations

Labyrinthine aplasia (Michel deformity)

ƒ The cochlea, vestibule, vestibular aqueduct
and cochlear aqueduct are absent.
ƒ In the majority of patients, the internal
auditory canal (IAC) consists of only a bony
facial canal. Nerves other than the facial nerve
are not present.

Figure: only stapes present

Cochlear aplasia
ƒ This is absence of the cochlea. The accompanying
vestibular system may be normal (Figures c and B) or
there may be an enlarged vestibule. (Figures D and C).

1617
Riyadh et al. Notes

Common cavity 711

ƒ In this malformation, the cochlea and vestibule are
represented by a single chamber (Figures E and D).
ƒ Theoretically, this structure has cochlear and vestibular
neural structures
ƒ Presence of the cochlear or
cochleovestibular nerve should be
demonstrated by MRI before cochlear
implantation.
ƒ It can be an ovoid or round structure.
ƒ Semicircular canals (SCCs) or their
rudimentary parts may accompany a
common cavity
ƒ The IAC usually enters the cavity at its
center.
ƒ A common cavity is more anteriorly
located than cochlear aplasia with
vestibular dilatation.
ƒ Cochlear implantation in a common cavity may result in good acoustic
stimulation but in cochlear aplasia with vestibular dilatation there will be
no stimulation with a CI.

Incomplete Partition (IP) of the cochlea

Three different types of IP cases were identified according to the defect in the
modiolus and the interscalar septa.

IP type I
This is the type of cochlea already described in ‘cystic cochleovestibular
malformation’
ƒ In this group, the cochlea lacks:
ƒ the entire modiolus
ƒ interscalar septa
ƒ It looks like an empty cystic structure. (Figure A)
ƒ It is accompanied by a large dilated vestibule (Figure B).

Cochlea (C), without the modiolus and interscalar septa, looks like an empty cystic
structure (A), is accompanied by dilated vestibule (v)

1618
Riyadh et al. Notes

712
ƒ Due to the defective development of the cochlear aperture and
absence of the modiolus, there is a defect between the IAC and the
cochlea.
ƒ The cochlea is located in its usual location in the anterolateral part of
the fundus of the IAC
IP type II
ƒ In a type II cochlea only the basal part of the modiolus is present
(Figures G and C).
ƒ This is the type of cochlea originally described by Carlo Mondini
ƒ IP type II with a minimally dilated vestibule and large vestibular aqueduct
constitutes the triad of the Mondini deformity. (Figure D )

ƒ The apical part of the modiolus and the corresponding interscalar septa
are defective.
ƒ This gives the apex of the cochlea a cystic appearance due to the
confluence of the middle and apical turns

IP type III
ƒ This is the type of cochlea observed and
reported in X-linked deafness
ƒ In this deformity, the interscalar septa are
present but the modiolus is completely absent
(Figures H and E).

ƒ The cochlea is placed directly at the lateral

end of the IAC instead of its usual
anterolateral position.(open immediately to
IAC)
ƒ This gives the cochlea a characteristic
appearance

1619
Riyadh et al. Notes

Hypoplasia 713
ƒ This is the cochlea with dimensions less than normal.
ƒ In smaller cochlea, it is usually difficult to count the number of turns with
computerised tomography (CT) and/or MRI.
ƒ the definition ‘cochlea with 1.5 turns’ should be used for hypoplasia
(particularly type III), rather than for IP type II cochlea
ƒ Three different types of cochlear hypoplasia can be identified.

Type I (bud-like cochlea)

ƒ The cochlea is like a small bud arising
from the IAC (Figures I and A).
ƒ Internal architecture is severely
deformed; no modiolus or interscalar
septa can be identified.

Cochlea (C) is like a small bud arising from

the IAC. Modiolus and interscalar septa
cannot be identified

Type II (cystic hypoplastic cochlea)

ƒ The cochlea is smaller in its dimensions with no modiolus and
interscalar septa, but its external architecture is normal (Figures 1J and
4B).
ƒ There is a wide connection with the IAC. The vestibular aqueduct is
enlarged and the vestibule is minimally dilated (Figure 4C).
ƒ This is the type of hypoplasia where a gusher and unintentional entry of
the electrode into IAC are possible.

TypE II (Cystic hypoplastic cochlea): Cochlea (c) is smaller in dimensions with no

modiolus and interscalar septa, but external architecture is normal (B).
Vestibular aqueduct (white arrow)is enlarged and vestibule (v) is minimally
dilated (c)

1620
Riyadh et al. Notes

Type III (cochlea with less than two 714turns)

ƒ The cochlea has a shorter modiolus and the overall length of the
interscalar septa is less, resulting in a smaller number of turns (less than
two turns)
ƒ The internal and external architecture (modiolus,
interscalar septa) is similar to that of a normal cochlea,
but the dimensions are less and hence the number of
turns is less (Figures K and D).
ƒ The vestibule and the SCCs are hypoplastic.
Cochlea (c) with fewer number of turns.
Internal and external architecture
(modiolus, interscalar septa) is similar to
normal cochlea, but the dimensions are
less and hence the number of turns is less
Ampulla of the posterior semicircular canal
is dilated (black arrow).

Large vestibular aqueduct syndrome

(LVAS)
ƒ This is the presence of an enlarged
vestibular aqueduct (the midpoint
between the posterior labyrinth and
operculum is larger than 1.5 mm)
ƒ In the presence of normal cochlea,
vestibule and SCCs (Figure 5A).

Narrow IAC
ƒ The width of midpoint of the IAC is
smaller than
2.5 mm (Figure 5B).
ƒ In cases of a narrow IAC, there is a
possibility of an absent or
hypoplastic cochlear nerve and this
must be checked with MRI.

1621
Riyadh et al. Notes

715
Preoperative radiological evaluation to diagnose the presence of an inner
ear malformation, to determine its type and to identify any other abnormality in
the temporal bone that may be encountered during surgery such as :
ƒ Type of malformation,
ƒ Pathologies in the middle ear and mastoid, Presence of the cochlear
nerve.
ƒ Sclerotic mastoid
ƒ Narrow facial recess
ƒ Facial nerve anomaly
ƒ Defect in the IAC with potential CSF gusher

Radiology may guide the decision to offer a CI in patients with inner ear
malformations

The decision to offer a CI is taken earlier in patients who are less likely to
achieve benefit from hearing aids, such as:
ƒ Common cavity
ƒ IP-I
ƒ IP-III.

In some patients hearing level may be suitable for hearing aids like
ƒ IP-II
ƒ LVAS

In some patients directly evaluated for auditory brainstem implantation (ABI):

ƒ Labyrinthine aplasia
ƒ Cochlear aplasia

HRCT
HRCT of the temporal bone should be obtained in axial and coronal sections
This gives very good bony details of the temporal bone. Classification can
easily be done following HRCT

MRI
MRI is important to diagnose:
ƒ Presence of nerves in the IAC
ƒ Cochlear fluids (indirectly can also show Cochlear fibrosis)

1622
Riyadh et al. Notes

716
The cochlear nerve can be absent in inner ear malformations and this is a
contraindication to CI surgery.

Aplasia of the cochlear cranial nerve needs to be ruled out with MRI, especially in
ƒ Common cavity abnormality
ƒ Narrow IAC visualized on CT scan (i.e. <2 mm in diameter)
ƒ CHARGE syndrome
Recurrent meningitis is not rare in this patient group (and MRI will show
indirectly cochlear fibrosis by demonstrating a decrease in signal intensity
coming from the inner ear fluids.

Surgical approach

The majority of CI operations in malformations can be done via the classical

transmastoid-facial recess approach.

Facial recess approach done through the

triangular space between:
ƒ Facial canal
ƒ Fossa incudis
ƒ Ear canal

There are two situations where facial recess

approach cannot be used:
1. Abnormal location of the facial nerve in the facial recess
• Course of the facial nerve may be altered in certain malformations such as
IP-I, common cavity or cochlear hypoplasia.
• It usually lies over the oval and round windows and the surgeon may be
unable to use the facial recess approach.

2. Unfavorable cochlear anatomy through the facial recess area

• In certain inner ear malformations, the cochlear promontory may not be
fully developed
• The round window and other necessary landmarks may not be visualized
and cochleostomy cannot be performed.

1623
Riyadh et al. Notes

Transcanal approach 718

717
Being used in standard CI surgery in some centers
• When the anatomy of the inner ear is not
severely distorted, a transcanal approach
can also be used for cochlear implantation
• In severe anomalies, such as common cavity
and hypoplastic cochlea, it may be difficult
to use this approach

The electrode cable can be then transferred to the mastoid cavity after making a
cut in the bony ear canal.

Transmastoid labyrinthotomy
By taking a direct transmastoid labyrinthotomy approach to the common cavity
and avoiding the facial recess and promontory dissection it may be possible to
implant the electrode array with maximum visualisation and minimal risk to the
facial nerve

Canal wall-down mastoidectomy with blind sac closure

This is a preferred approach when there is:
1. Facial nerve location prevents the standard facial recess approach,
2. In patients with uncontrollable gusher and recurrent meningitis

Using a canal wall-down procedure provides better visualization of

the promontory, and oval and round windows
There are two disadvantages of this procedure:
1. The duration of the operation is increased because the
whole skin of the ear canal and the tympanic membrane must be
completely removed.
2. There is a possibility of leaving some squamous
epithelium in the cavity which could become cholesteatoma
within a period of a few months.

This may create a surgical problem because MRI cannot be used to

differentiate between cholesteatoma and other soft tissue masses in
patients with a CI.

1624
Riyadh et al. Notes

718

Facial nerve anomalies in malformations

1625
Riyadh et al. Notes

719

Facial nerve: normal course and abnormalities as seen on HRCT.

A: Normal HRCT. Axial section showing the relationship between the facial nerve
(F) and the oval window (OW) Vertical segment of the facial nerve is located
lateral and posterior to the oval window.

B: Anteromedial dislocation of the facial nerve. Axial section showing the facial
nerve which is dislocated anteriorly and medially lying adjacent to the oval
window.

C: Normal HRCT. Coronal section showing the relationship between the facial
nerve (F) and the oval window (OW). The tympanic segment of the facial nerve
lies inferior to the lateral semicircular canal (LSCC).

D: Anterior dislocation of the facial nerve. Instead of the horizontally lying

tympanic segment, vertical segment is seen on the coronal section inferior to the
LSCC.

1626
Riyadh et al. Notes

CSF gusher 720

Definition: The term ‘gusher’ is generally used in the literature to describe the
egress of pro-fuse clear fluid upon making an opening into the inner ear.
This is common during surgery in inner ear malformations either:
• Cochlear implant cochleostomy
• Stapedictomy

In cases of gusher, the fluid coming from the inner ear cannot be perilymph, as
the inner ear contains only a few microliters of perilymph.
The profuse fluid coming from the inner ear is CSF and is due to a defect of
variable size between the malformed inner ear and the IAC.

Incidence
The majority of the papers reported the incidence of gusher to be
between 40-50% of their patients with inner ear malformations.

Types of gusher
A gusher of CSF is the result of an abnormal bony defect at the lateral end of the
internal auditory meatus (Figure A and B).

Normally, the CSF in the subarachnoid space extends laterally into the IAC as
far as the fundus, where it is separated from the
perilymph by the bony plate of the lamina cribrosa.

In some congenitally dysplastic ears, there is a

defect at the lateral end of the IAC, allowing direct
confluence of CSF and perilymph.

Two types has been described:

• Oozing (A gentle flow of clear fluid)
• Gusher (a profuse flow)

Oozing:
Result of a small defect between the malformed inner ear and the IAC.
Intermittent flow of CSF in small quantities
Usually stops after a few minutes.
Small defect between the IAC and the malformed ear
Easily controlled CSF outflow with soft tissue packing around the electrode.
More common in type II and LVAS.

1627
Riyadh et al. Notes

Gusher: 721
Result from wide communication between the subarachnoid space and inner ear.
Profuse CSF outflow upon making the cochleostomy.
Lasts between 10 and 20 minutes.
This is the more serious type with more risk of causing postoperative meningitis.
With IP-I and some patients with IP-II.
IP-III is the least frequent form of IP anomaly

Radiology
Demonstrates the defect at the lateral end of the IAC.
HRCT is the best method to demonstrate the defect at the lateral end of the IAC

Treatment
It is very important to firmly pack a piece of muscle around the electrode lead at
the level of the cochleostomy to prevent CSF fistula in the postoperative period.
If the seal is not watertight, there is a risk of permanent CSF leakage with the
potential risk of meningitis.

Size of the cochleostomy

Small cochleostomy:
Allowing the electrode cable to partly block the flow of CSF,
reinforced with connective tissue, muscle and fibrin glue
(Figure A and B).

It was observed that it was very difficult to effectively insert

pieces of muscle or fascia around the electrode inside the
cochleostomy.

Large cochleostomy:
Allows easy insertion of the electrode and seems to make
introduction of muscle around the electrode reasonably easier
(Figure C).

Proper application of muscle tissue around the cochleostomy

represents the first line of barrier against CSF leakage and the
flow of CSF stops quickly when a proper seal has been
established.

1628
Riyadh et al. Notes

Helpful maneuvers: 722

• Elevating the head of the operating table reduces the flow from the
gusher.
• Putting the tip of the suction on the bone at the edge of the hole keeps
the area round the hole and also that part of the middle ear clear of fluid

Continuous lumbar drainage (CLD)

Although rarely required, this method should be applied if the gusher cannot be
controlled effectively during surgery or the child develops rhinorrhoea after
surgery.
Usually CLD is kept in its place for four to five days
The purpose of CLD is to lower the pressure of CSF
It is also important to temporarily close the Eustachian tube orifice with Surgicel
to prevent CSF leakage into the nasopharynx in the postoperative period

Use of soft tissue around the electrode

Application of soft tissue (muscle or fascia) is important in cases of gusher.
Different ways:
• Fascia or muscle can be applied as small pieces separately around the
electrode.
• Harvest a small round piece of fascia, about 5–6 mm in diameter.
The electrode is passed through a hole made in the centre of the
fascia block (Figure D). When the electrode is inserted the fascia is
advanced to the level of the cochleostomy around the electrode.

Eustachian tube obliteration

After sealing the cochleostomy, the Eustachian tube is temporarily blocked to
prevent escape of the CSF into the nasopharynx.
Oxidised cellulose (SURGICEL) is the material usually preferred for this purpose.

Subtotal Petrosectomy (BLIND SAC)

In cases of intractable CSF leakage, more secure sealing of the leak can be
achieved by subtotal petrosectomy
This operation has important steps:
1. The lateral part of the skin of the external meatus is everted and closed as a
blind sac.
2. The medial part of the skin of the ear canal and the tympanic membrane are
completely removed.
3. The canal wall is taken down, and the facial canal and oval and round windows
are exposed.
4. The Eustachian tube is blocked.
5. The mastoid cavity is obliterated with abdominal fat. Obliteration is necessary
in patients with gusher.

1629
Riyadh et al. Notes

Additional measures: 723

Head elevation
48 hours of bed rest decrease CSF leakage.
Acetazolamide can be used to decrease CSF production
Avoid heavy lifting

CSF fistula and meningitis

CSF fistula in inner ear malformations is associated with considerable morbidity
and mortality.
It may easily lead to recurrent meningitis unless there is a surgical intervention
to repair the fistula.
The majority of CSF fistulae are located at the stapes footplate and occasionally
encountered at the cochleostomy site

Pathogenesis:
Inner ear malformations with a wide defect in the lamina
cribrosa and modiolus may cause CSF to come into contact
with the medial surface of the oval and round windows.
Continuous CSF pressure may cause erosion and then a
defect and fistula at the stapes footplate (Figure 10).

Site of fistula:
Majority of spontaneous CSF fistulae are reported to be located in the oval
window.
Sometimes the leak site can be the cochleostomy.
Contralateral non implanted site can be the source.

Radiology:
Radiology is the most important tool to diagnose CSF leaks preoperatively and
the predisposing anatomic factors.
The presence of inner ear malformations, a defect in the lamina cribrosa or a
bone fracture on HRCT may be the aetiology of a CSF gusher.

CT cisternography:
• can show CSF fistula in patients with CSF otorhinorrhoea and
unilateral hearing loss
• Which is an invasive method, demonstrates the fistula reliably in
patients with a CI.

A non-invasive method for confirming this finding is a FSE T2-weighted MRI

sequence through the region

MRI (using 3DFSE T2WI and 3D FIESTA sequences) a useful technique in the
assessment of patients with CSF fistulae

1630
Riyadh et al. Notes

724
Treatment
Middle ear exploration
Once the diagnosis is made, the middle ear should be explored to diagnose the
site of the leak and treat the fistula.

Oval window leak:

After removing the ossicles, the vestibule is packed through the oval window
with a layer of muscle or fascia followed by an injection of fibrin glue
If the stapes crurae can be preserved during surgery, then they may be helpful
in stabilising the soft tissue graft in the oval window.
Another layer of muscle or fascia may be used on top.
Intraoperative CLD and lumbar drainage continued postoperatively

Cochleostomy site leak:

This should be sealed by Temporalis fascia packing around the electrode array
and into the vestibule until the leakage stopped.
A piece of temporalis muscle then placed in the middle ear space on top of the
fascia. The wound then closed, and a lumbar drain inserted.

Subtotal petrousectomy
In recurrent meningitis some recommended subtotal petrosectomy with removal
of the middle ear mucosa and closure of the Eustachian tube and ear canal

1631
 725
Inner Ear Dysmorphologies
Michel Aplasia (Complete Labyrinthine
Aplasia with Absent Cochlea)
t
Pathophysiology: complete failure of the development of the inner
ear at week 3 of gestation, autosomal dominant
t
Dx: CT reveals hypoplastic petrous pyramid and absent cochlea and
labyrinth

Mondini Dysplasia (Incomplete Partition)

t
NPTU DPNNPO DPDIMFBS NBMGPSNBUJPO MJLFMZ CFDBVTF PG BNCJHVPVT
definition)
t
Pathophysiology: developmental arrest of the bony and membranous
labyrinth at week 7 of gestation; can be autosomal dominant
t
BTTPDJBUFE
XJUI
BO
JODSFBTFE
SJTL
PG
QFSJMZNQIBUJD
HVTIFS
BOE

meningitis from a dilated cochlear aqueduct
t
Dx: CT reveals a 1.5 turn (variable) cochlea with no interscalar
septum/deficient modiolus, semicircular canals may be absent or
wide, enlarged vestibular aqueduct

Enlarged (Large) Vestibular Aqueduct

t
NPTU DPNNPO SBEJPHSBQIJD BCOPSNBMJUZ
t
Pathophysiology: multiple hereditary mechanisms
t
BTTPDJBUFE
XJUI
FBSMZ
POTFU
4/)-

BOE
.POEJOJ
EZTQMBTJB

also seen in DFNB4-associated hearing loss, Pendred syndrome,
branchio-oto-renal syndrome
t
SSx: fluctuating, typically progressive SNHL or mixed HL with
variable vestibular symptoms
t
Dx: CT temporal bone or MRI IAC; >1.5 mm vestibular aqueduct
diameter at the midpoint between the common crus and the
operculum
t
Rx: prevent sudden decrements in hearing by avoiding head trauma
(judicious helmet use, no contact sports)

Scheibe Dysplasia (Cochleosaccular Dysplasia)

t
Pathophysiology: partial or complete membranous aplasia of the
pars inferior (cochlea and saccule) with a normal pars superior
(semicircular canals and utricle); can be autosomal recessive
t
TZOESPNJD
BTTPDJBUJPO
JODMVEJOH
6TIFS
BOE
8BBSEFOCVSH
BMTP

associated with congenital rubella
 726

defect, definitive diagnosis may only be determined by histologic

examination

Acquired Prenatal (Congenital

Infectious) Hearing Loss
t
JODMVEFT
503$)
JOGFDUJPOT
t
Congenital Toxoplasmosis: delayed onset, progressive SNHL
t
Congenital Rubella: ossicular and cochlear disorders, severe-
profound SNHL, may cause delayed endolymphatic hydrops
t
Congenital Cytomeglalovirus (CMV): most common cause of
OPOHFOFUJD
IFBSJOH
MPTT
_
PG
OFXCPSOT
DPOUSBDU

PG
UIPTF

have symptoms including mild-profound progressive SNHL; new
laws in several US states to provide CMV education to all expectant
mothers and testing opportunities prior to discharge; Dx: PCR
(or serology) preferably <3 weeks of life, Rx: consider 6 months
valganciclovir if test positive
t
Congenital Syphilis: presents at ≤2 years of life or in a delayed form
at 2nd–3rd decade of life, Hennebert’s sign (positive fistula), may
present with endolymphatic hydrops; Dx: FTA-ABS, VDRL

Autosomal Recessive Causes of Hearing Loss

Nonsyndromic Autosomal Recessive Disorders
t
NPSF
DPNNPO
UIBO
TZOESPNJD
t
JEFOUJGJFE
CZ
HFOFUJD
MPDJ
EFOPUFE
XJUI
%'/B- prefix
t
CZ
EFGJOJUJPO
OP
PUIFS
QIZTJDBM
PS
TZTUFNJD
GJOEJOHT
OPOTZOESPNJD

Connexin Mutations
t
NPTU
DPNNPO
DBVTF
PG
IFSFEJUBSZ
OPOTZOESPNJD
IFBSJOH
MPTT
t
DFNB1 BDDPVOUT
GPS
_
PG
DPOHFOJUBM
TFWFSFUPQSPGPVOE

autosomal recessive nonsyndromic hearing loss
t
GJB2 gene (encodes connexin 26 protein, most common) and GJB6
gene (encodes connexin 30) reside at DFNB1 locus
t
35delG is most common connexin 26 mutation.
t
SSx: mild to profound SNHL, usually normal vestibular function

Syndromic Autosomal Recessive Disorders

Usher Syndrome
t
NPTU
DPNNPO
DBVTF
PG
autosomal recessive syndromic hearing loss
 727
t
NPTU
DPNNPO
DBVTF
PG
EFBGCMJOEOFTT
EVBM
TFOTPSZ
JNQBJSNFOU
t
Etiology: primarily autosomal recessive (may also be autosomal
dominant or X-linked recessive) results in variable expression
t
Otologic SSx: congenital SNHL, vestibular dysfunction (variable)
t
Other SSx: progressive retinitis pigmentosa (delayed tunnel vision
and blindness), mental retardation, cataracts, delayed walking
t
Types: I: profound congenital SNHL, vestibular areflexia, adolescent-
onset retinitis pigmentosa; II: moderate to severe congenital SNHL,
legally blind by mid-adulthood, normal vestibular function; most
common form; III: progressive SNHL, varied progression of
blindness, progressive vestibular dysfunction
t
Dx: ophthalmology including electroretinography, genetic testing,
vestibular testing showing areflexia

Pendred Syndrome
t
TFDPOE
NPTU
DPNNPO
DBVTF
PG
BVUPTPNBM
SFDFTTJWF
TZOESPNJD
IFBSJOH

loss
t
Etiology: mutation in gene (usually SLC26A4 [PDS]) producing
the pendrin protein resulting in defective iodine metabolism and
organification; SLC26A4 mutation can cause spectrum of disease
ranging from Pendred syndrome to DFNB4 (nonsyndromic hearing
loss)
t
Otologic SSx: mild-profound SNHL (can be mixed HL due to
third window effect), normal middle and outer ear, associated with
Mondini deformity and enlarged vestibular aqueduct, variable
vestibular dysfunction
t
Other SSx: euthyroid multinodular goiter at 8–14 years old
t
Dx: genetic testing, positive perchlorate test (increased iodine release
from thyroid in response to perchlorate)
t
Rx: exogenous thyroid hormone if necessary (suppress goiter growth,
no effect on hearing), thyroidectomy typically not required

Jervell and Lange-Nielsen Syndrome

t
UIJSE
NPTU
DPNNPO
DBVTF
PG
BVUPTPNBM
SFDFTTJWF
TZOESPNJD
IFBSJOH

loss
t
Etiology: genetically heterogeneous with several responsible genes
resulting in severe SNHL and cardiac defects; most commonly
associated with mutations in KCNQ1
t
Otologic SSx: severe to profound bilateral SNHL
t
Other SSx: cardiac abnormalities, recurrent syncope (may be
misdiagnosed as epilepsy), sudden death
t
Dx: ECG (prolonged QT, large T-waves)
t
Rx: β-blockers, defibrillator
 728
Goldenhar Syndrome (Oculoauriculovertebral
Spectrum, Hemifacial Microsomia) (see p. 599)

Autosomal Dominant Causes

of Hearing Loss
Nonsyndromic Autosomal Dominant Disorders
t
JEFOUJGJFE
CZ
HFOFUJD
MPDJ
EFOPUFE
XJUI
%'/A-prefix
t
PGUFO
XJMM
IBWF

QBSFOU
XJUI
IFBSJOH
MPTT

Syndromic Autosomal Dominant Disorders

Waardenburg Syndrome
t
NPTU
DPNNPO
DBVTF
PG
BVUPTPNBM
EPNJOBOU
TZOESPNJD
IFBSJOH
MPTT
t
Etiology: mutation in PAX3 gene (in types I and III)
t
Otologic SSx: unilateral or bilateral SNHL, may have vestibular
dysfunction
t
Other SSx: pigmentary abnormalities (heterochromia iridis, white
forelock, patchy skin depigmentation), craniofacial abnormalities
(dystopia canthorum [widely spaced medial canthi, telecanthus],
synophrys [confluent eyebrows], broad nasal root)
t
Types: I: dystopia canthorum, 50% have SNHL; II: no dystopia
canthorum, 80% have SNHL; III: skeletal abnormalities, unilateral
ptosis; IV: Hirschprung disease

Stickler Syndrome (Progressive Arthro-Ophthalmopathy)

t
Etiology: mutation in collagen-producing genes (COL2A1 in Stickler
type 1)
t
Otologic SSx: progressive SNHL (may have mixed HL)
t
Other SSx: ocular abnormalities (myopia, retinal detachment,
cataracts), Marfanoid habitus (tall and thin), arthritic abnormalities
(joint hypermobility, early arthritis), Pierre-Robin sequence

Branchio-Oto-Renal Syndrome (Melnick-Fraser Syndrome)

t
Etiology: mutation most commonly in EYA1 gene (chromosome 8q)
causing abnormal development of branchial arches (including ears)
and kidneys
t
Otologic SSx: pinna deformities; preauricular ear pits, fistulas,
or tags; varied mixed hearing loss with ossicular and cochlear
malformations; may have an associated Mondini deformity or
enlarged vestibular aqueduct
 Pediatric Otolaryngology 589

729
t
Other SSx: varied renal abnormalities (agenesis, mild dysplasia);
branchial anomalies; lacrimal duct stenosis
t
Dx: renal involvement may be asymptomatic and only detectable
with pyelography or renal ultrasound

Other Syndromic Autosomal Dominant Disorders

t
Treacher Collins Syndrome (Mandibulofacial Dysostosis) (see
p. 602)
t
Neurofibromatosis 1 and 2 (see p. 410)
t
Apert Syndrome (Acrocephalosyndactyly) (see p. 596)
t
Crouzon Syndrome (Craniofacial Dysostosis) (see pp. 597–598)

X-Linked Causes of Hearing Loss

Nonsyndromic X-Linked Disorders
t
JEFOUJGJFE
CZ
HFOFUJD
MPDJ
EFOPUFE
XJUI
%'/X-prefix

X-Linked Stapes Gusher

t
Etiology: mutation in the POU3F4 gene
t
Otologic SSx: congenital stapes fixation with perilymphatic gusher,
enlarged IAC, mixed HL
t
Other SSx: typically nonsyndromic but may be associated with
choroideremia and mental retardation
t
Dx: CT temporal bone
t
Rx: consider stapes surgery cautiously

Syndromic X-Linked Disorders

Alport Syndrome
t
Etiology: X-linked mutation in type IV collagen gene (COL4A5) >
autosomal recessive or dominant; effects in the glomerular basement
membrane result in progressive renal disease
t
Otologic SSx: slowly progressive SNHL (bilateral degeneration of
organ of Corti and stria), presents in first decade of life
t
Other SSx: renal dysplasia/agenesis, progressive nephritis, ocular
disorders (myopia, cataracts)
t
Dx: urinalysis, renal ultrasound, BUN, serum creatinine,
immunohistochemistry
t
Rx: dialysis and renal transplant

Otopalatodigital Syndrome
t
Etiology: mutation in FLNA gene
590 Otolaryngology-Head and Neck Surgery

730
t
Otologic SSx: ossicular malformation (CHL)
t
Other SSx: craniofacial deformities (supraorbital deformity, flat
midface, small nose, cleft palate, hypertelorism), digital abnormalities
(broad fingers and toes), short stature, mental retardation

Other Hearing Disorders

t
Auditory Neuropathy (see p. 409)
t
Central Auditory Processing Disorder (see p. 409)
t
Sudden Sensorineural Hearing Loss (SSNHL) (see p. 407)
t
Noise-Induced Hearing Loss (see p. 408)
t
Ototoxin-Induced Hearing Loss: (see p. 409)

Otitis Media
Introduction
t
see also pp. 377–387
t
Definition of Acute Otitis Media
1. moderate to severe bulging of the tympanic membrane, or
2. new onset of otorrhea of middle ear origin, or
3. mild bulging of the tympanic membrane and new-onset (<48
hours) ear pain, which can be seen as holding/tugging/rubbing of
the ear, or intense erythema of the tympanic membrane

Medical Treatment of Otitis Media

Acute Otitis Media (AOM) Oral Antibiotic Guideline
(2013 American Academy of Pediatrics)
t
<6 months old with SSx of nonsevere or severe AOM: antibiotics
t
≥6 months old with severe SSx of AOM (moderate–severe otalgia,
PUBMHJB
ǚ
IPVST
UFNQFSBUVSF
ǚ¡
$ 
BOUJCJPUJDT
t
6–23 months old with nonsevere bilateral AOM (mild otalgia <48
IPVST
UFNQFSBUVSF
¡
$ 
BOUJCJPUJDT
t
6–23 months old with nonsevere unilateral AOM: offered antibiotics
or observation with close follow-up; if observing, antibiotics should
be given if SSx worsen or fail to improve within 48–72 hours of onset
t
ǚ24 months old with nonsevere unilateral or bilateral AOM: either
antibiotics or observation
t
First-Line Antibiotics: amoxicillin (80–90 mg/kg/day) if not allergic,
not received antibiotics in <30 days, no purulent conjunctivitis (more
likely non-typeable H influenzae which is resistant), and no history of
recurrent AOM unresponsive to amoxicillin; amoxicillin-clavulanate
 Inner Ear Malformations
Riyadh et al. Notes
Cochlea Vestibule SSC VAD IAM Schematic CT
Labyrinthine Narrow
Aplasia X X X X contains FN -
(Michel) only
Narrow
Normal/Dilated
Cochlear contains FN
X Posteriorly ✓ ✓
Aplasia and vestibular
located
only
Single chamber
Common Rudim
Anteriorly located ✓ ✓
Cavity entary
IAM enters at its center
Normal,
Incomplete
Defect
Partition – I - No Mod
Dilated ✓ ✓ between IAM
(Cystic - No ISS
and Cochlea
cochlea)
(Gusher)
- No Apical Mod
Incomplete
- No Apical ISS
Partition – II Dilated ✓ Dilated ✓
(Cystic cochlear
731

(Mondini)
apex)
- No Mod
Incomplete - Present ISS ✓
Dilated ✓ Dilated
Partition – III Located at lateral (Gusher)
end of IAM
Cochlear - No Mod
✓
Hypoplasia - No ISS ✓ ✓ ✓
(Gusher)
Type-I (Bud-like cochlea)
Normal, wide
- No Mod
Cochlear connection
- No ISS
Hypoplasia Dilated ✓ Dilated with IAM
(Cystic hypoplastic
Type-II (Gusher)
cochlea)

Cochlear - Small Mod

Hypo
Hypoplasia - Small ISS Hypoplastic Dilated ✓
plastic
Type-III (1.5 turn Cochlea)

1632
 732

AUTOIMMUNE INNER EAR DISEASE

Inner Ear Immune Response

 Normal state  inner ear contains immunoglobulin and endolymphatic sac
contains immunocompetent cells
 Perilymph contains immunoglobulin at a level of 1/ 1,000 the concentration
found in serum (higher than in CNS)
 IgG > IgM and IgA; inner ear protection by neutralization, opsonization,
complement fixation
 Endolymphatic sac  full array of immunocompetent cells (helper and
suppressor T cells, macrophages, B cells with antibodies); not present in
cochlea
 Endolymphatic sac is close to lymphatics that drain into jugular vein and into
retropharyngeal LN (endolymphatic sac may be the originating site for local
immune response)
 Endolymphatic hydrops shown on histology with antigenic challenge
 Previous immunization has an effect on the final outcome of an inner ear
immune response in animal studies
 Endolymphatic sac appears crucial in antigen processing and appears to be
the site from which perilymph antibody emanates
 IL-2 only found after antigenic challenge
o IL-1 released by activated macrophages
o IL-1 stimulation of T-helper cells causes release of IL-2
o IL-2 functions include: activation of T-helper, T-cytotoxic, T-suppressor
cells; activation of B cells; enhancement of natural killer activity;
chemoattraction for polymorphonuclear cells, monocytes, and
lymphocytes; immunoregulation for prevention of autoimmune disease
 TGF-beta (transforming growth factor) also found after stimulation
o Chemoattractant for monocytes, T cells, and, neutrophils; while
increasing levels of IL-1, IL-6, and platelet-derived GF
o Negative feedback role  interferes with IL-2 response, deactivates
macrophages, inhibits production of interferon-alpha and TNF-alpha
 In addition to contributions from the endolymphatic sac, inner ear also
receives systemic immune cells for protection against viral and bacterial
antigens
 Spiral modiolar vein appears to play a role in systemic cellular infiltration
o Spiral modiolar vein transforms into a high endothelial venule-like
structure (high endothelial venules are specialized post-capillary
venules where egress of lymphocytes from circulation to LN occurs)
o Macrophages and granulocytes present at 6 hrs post-challenge
o IgG cells on day 1
o T-helper cells present on day one and peak at 2-3/52
o T-suppressor cells don’t present until 3/52;
o Fibroblasts and endosteal cells proliferate as of day 1 post-
challenge; fibrotic tissue as early as 1/52 and ossification begins by
3/52
 ICAM-1 (intercellular adhesion molecule-1)
o Acute inflammation leads to the transformation and adherence of
lymphocytes to and within vascular wall ICAM-1
o Involved in interactions between leukocytes and endothelial cells and
ultimate extravasation of cells

Otology
1
Chapter 152 (6) Hosam’s Note
733

 Causes of labyrinthitis ossificans:

1. Labyrinthitis (purulent or sterile)
2. Advanced otosclerosis
3. Autoimmune inner ear disease
4. Temporal bone trauma
5. Surgery (Labyrinthectomy or CI)
6. Meningitis
7. Vascular occlusion

 Immune response contributes to hearing loss

o Degeneration of the organ of Corti, stria vascularis, spiral ganglion,
mild hydrops; also, lack of clearing of the extracellular matrix and
subsequent ossification

Autoimmune Immunopathology
 Three mechanisms for autoimmune disease in general:
o Autoantibodies against tissue antigens
o Deposition of Ag-Ab immune complexes in tissue
o Infiltration/destruction of tissue by specific cytotoxic T-cells
 Diseases with cochlear effect:
o Polyarteritis nodosa – rare  ischemic changes
o Wegeners – middle and inner ear involvement
o SLE – progressive SNHL and vertigo
o RA – not confirmed
o Cogan syndrome

Intestitial keratitis and vestibuloauditory dysfunction (possible
autoimmune cause)

May actually be organ-specific, unlike rest

 Some studies show 68,000 dalton (68-Kilodalton) anti-inner ear antibody

(found in serum or Western blot); patients showed improvement with steroids
 Lymphocyte transformation test  test of cell-mediated immunity used as
a predictor of autoimmune ear disease
 Possible tests
o Lyme titre
o ESR, CRP
o C1q binding assay
o ANCA
o Treponemal pallidum microhemagglutination assay
o Anti-cardiolipin antibody
o Western blot for HSP-70
 Western blot for HSP-70 seems best fort predicting steroid responsiveness
(positive 68-kD Western blot)
 Another cross-reactive antigen may be KHRI-3 monoclonal antibody assay
 Westem blot assay is the most specific test and should be done as the initial
serologic test for autoimmune inner ear disease
 Some evidence that delayed hypersensitivity responses (type IV-mediated T
cell damage) may play a role

Otology
2
Chapter 152 (6) Hosam’s Note
734

Treatment
 Early institution of high-dose prednisone
o 60 mg OD for about 1 mos
o Short-term or lower dose long-term therapy have shown some
ineffectiveness or fraught with the risk of relapse
o During the taper, if hearing worsens the therapy is re-started
o Response rates ~ 60%
 Predictor of imminent relapse is loud tinnitus
 Defined as an improvement in threshold of 15 dB at 1 frequency, 10 dB at 2
consecutive frequencies, or a significant improvement in discrimination score
 Addition of cytotoxic meds for recurrent failure to taper off steroids
 Methotrexate (less toxic) and cyclophosphamide
 MTX
o 7.5-20 mg weekly with folic acid
o Effect may take 1-2 mos to achieve (prednisone should be maintained)
o If not responsive to prednisone, MTX unlikely to help
 Cyclophosphamide
o Severe HL, +ve 68-kD Western blots, no response to steroids MTX
o PO 1-2 mg/ kg/ day with lots of fluid (decreases the risk of
hemorrhagic cystitis or drug effects on bladder)
o Risk of permanent sterility; do not use in kids
 Both cytotoxic meds need monitoring
 Plasmapheresis
 Etanercept (TNF-alpha blocking agent- used in the treatment of RA)

Otology
3
Riyadh et al. Notes
735
Labyrinthine Ossificans

x What is Labyrinthine Ossificans (LO)?

o Pathologic formation of new bone within the lumen of the otic capsule

x What are the causes of LO?

1. Bacterial meningitis leading to Suppurative labyrinthitis (Most common
cause)
2. Suppurative labyrinthitis associated with AOM.
3. Advanced Otosclerosis
4. Temporal bone trauma
5. Autoimmune inner ear disease
6. Vascular ischemia of labyrinthine artery
7. Leukemia

x What is the most common cause of LO?

o Bacterial meningitis.
o Leads to Suppurative labyrinthitis
o 80% of patients with profound postmeningitic SNHL have LO.
o Complete ossification is associated with a very poor prognosis for
residual hearing.

x What are the most common organisms causing meningitis?

o S pneumoniae (Most common)
o Neisseria meningitidis
o H influenzae

x Does vaccination in children reduce the risk of meningitis?

o S. pneumoniae vaccination has decreased the incidence of severe
S.pneumoniae infections.
o Haemophilus influenzae vaccination has decreased the incidence of
Haemophilus influenzae meningitis.

x Which organism is the most common to cause ossification?

o Post-meningitis SNHL greatest with S pneumoniae (20-30%).
o Lowest with Haemophilus influenzae (5%).

1633
Riyadh et al. Notes
736
x What are the risk factors for post-meningitis SNHL?
o Disease Factors:
1. S. pneumonia
2. High ICP
3. Low CSF Glucose
4. Long hospital stay > 14 days
5. Seizure
o Treatment Factors:
1. Delay treatment
2. Partial antibiotic treatment
3. No steroid therapy

x What are the stages of post-meningitis SNHL?

1. Acute stage:
o Purulence fills the perilymphatic space.
o Begins within days after the onset of meningitis.
o Seen in MRI as cochlear enhancement (Earliest finding).
2. Fibrous stage:
o Fibroblastic proliferation within the perilymphatic space.
o Begins 2 weeks after the onset of meningitis.
o Seen in MRI (More sensitive) but not in CT (False negative
results in 60%).
3. Ossification stage:
o Bone formation in the basal turn of cochlea with obliteration of
perilymphatic and endolymphatic spaces.
o Begins as early as 2 months after the onset of meningitis.
o Seen in both CT and MRI.

x Where is the earliest site of involvement in LO and why?

o Scala tympani of the basal turn due to its relative decreased blood
flow.

x When will be the onset of hearing loss following meningitis?

o Ossification has been noted to occur within a year after meningitis,
although the hearing loss may occur as early as 48 hours after
infection.

x What is the recommended protocol Post-meningitis?

o Audiological evaluation for all post-meningitis patients should be done
as soon as the clinical condition of the patient allows.
o Radiological evaluation for all post-meningitis patients should be done
with Gad-MRI within the 1st month after meningitis (to evaluate for
cochlear enhancement).

1634
Riyadh et al. Notes
737
x What are the findings on MRI in patients with post-meningitis SNHL?
o Gad T1 MRI:
ƒ Cochlear Enhancement:
x Earliest imaging finding of post-meningitis SNHL.
x Seen as early as 1st day of infection till 8 weeks after
infection.
x Indicates active inflammation and found to be related to
the occurrence of SNHL.
x Accentuating the necessity for rapid cochlear
implantation.
o T2 MRI:
ƒ Cochlear Obliteration:
x Detect cochlear lumen obliteration caused by fibrosis or
ossification.
x Seen as early as 2 weeks of infection..
x Most sensitive imaging tool (90-100% accurate in
predicting intra-op difficulty in insertion of CI electrode).

1635
Riyadh et al. Notes
738
x What is the finding on CT in patients with post-meningitis SNHL?
o Labyrinthine ossification of basal turn (Most common).
o Seen as early as 2nd month of infection
o Sensitivity of 70% to detect cochlear obliteration (only detects
ossification not fibrosis).

x What is the grading of Basal turn LO on CT scan?

1636
Riyadh et al. Notes
739

1637
Riyadh et al. Notes
740
x What are the proven medications to prevent post-meningitis SNHL?
1. Ceftazidime:
ƒ First-line agent for the prevention of otogenic and meningogenic
labyrinthitis.
2. Steroid:
ƒ Reduce incidence of SNHL loss associated with bacterial
meningitis.
3. NSAIDs:
ƒ Reduce incidence of SNHL when administered early course of
meningitis.

x What are the options of hearing rehabilitation in unilateral post-

meningitis SNHL?
1. Hearing aid
2. Contra Lateral Routing of Signals (CROS)
3. Bone Anchored Hearing Aid (BAHA)
4. CI

x What are the options of hearing rehabilitation in bilateral post-

meningitis SNHL?
1. CI

x What is the topographic representation of frequency in the cochlea?

x What is the topographic representation of frequency in the CI

electrode?

1638
Riyadh et al. Notes
741
x What is the appropriate timing of CI in post-meningitis SNHL?
o Exact timing remains controversial.
o Preferred to be earlier to avoid the possibility of severe ossification.

x What is the surgical approaches for CI in LO?

o Standard mastoidectomy.
o Facial recess approach.
1. Round window Approach:
ƒ Indicated for minimal ossification at the distal part of the basal
turn.
ƒ Requires initial drilling until a lumen is identified.
ƒ Insertion of arrays from Scala Tympani of Basal turn toward the
apex.
2. Scala Vestibuli Cochleostomy (Upper Retrograde Approach):
ƒ Indicated for complete ossification of entire basal turn.
ƒ Performed by doing Scala Vestibuli (Apical) cochleostomy:
x Anterior to the oval window and inferior to cochleariform
process.
ƒ Insertion of arrays from Scala Vestibuli of Middle turn toward
the base.
ƒ Risk of injury to the labyrinthine segment of the facial nerve.
3. Double/Split Array Approach:
ƒ Indicated for complete ossification of entire cochlea.
ƒ Performed by doing 2 Cochleostomies:
x Scala Tympani Cochleostomy:
o Anterior and Inferior to RW
o Allows insertion into Scala Tympani of Basal turn.
x Scala Vestibuli Cochleostomy:
o Anterior to OW and inferior to cochleariform
process.
o Allows insertion into Scala Vestibuli of Middle turn.

1639
Riyadh et al. Notes

Auditory Neuropathy 742

x Auditory neuropathy/auditory dyssynchrony (AN/AD) is a condition that
affects the neural processing of auditory stimuli.
x Patients with this disorder are able to respond to sounds appropriately,
but their ability to decode speech and language is hindered.
x AN/AD has only recently been described.
x In the late 1970s, clinical investigators began to describe groups of
patients with normal or slightly elevated audiogram pure tone thresholds
accompanied with absent or severely abnormal auditory brainstem
responses (ABRs).
x With the advent of the otoacoustic emissions (OAEs) in the mid 1980s,
these groups of patients were found to have normal cochlear function.
x The finding of normal cochlear function accompanied with abnormal
brainstem responses was defined in 1996 as auditory neuropathy (AN).
x Whether this represents a true auditory nerve neuropathy is debatable.
x Further investigations led to the conclusion that AN may truly represent a
dyssynchronous auditory nerve rather than a neuropathy.
x This finding gave rise to the newer term of auditory dyssynchrony
(AD).[1] For the purposes of this summary, AN and AD are considered
synonymous (ie, AN/AD).

Pathophysiology
x The term auditory neuropathy/auditory dyssynchrony (AN/AD) describes a
diagnosis that affects a small group of patients with hearing loss and
speech intelligibility scores out of proportion with presumed hearing loss.
x Many authors have suggested that the abnormalities that cause AN/AD
reside within the lower auditory system.
x Specifically, the spiral ganglion cells, auditory nerve, or the auditory
brainstem nuclei have all been implicated.
x The combination of a dysfunctional auditory nerve with preservation of
cochlear function can theoretically be caused at several different points
along the lower auditory pathway.
x The following abnormalities have been proposed:
o Injury to the synaptic junction between inner hair cells of the
cochlea and dendrites of spiral ganglion neurons
o Direct damage to the dendrites of the spiral ganglion neurons
o Direct injury to the spiral ganglion neurons
o Direct axonal damage to the auditory nerve that causes a cascade
of damage to the lower auditory nuclei
x Several risk factors have been speculated to contribute to AN/AD. Those
include the following:
o Neonatal history of anoxia;
o Neonatal history of hyperbilirubinemia;
o Neonatal history of mechanical ventilation, hypoxia, or both;
o Congenital brain abnormalities;
o Low birth weight < 1.5kg
o Extremely premature birth (< 28 wk);
o Genetics or family history of AN/AD

1640
Riyadh et al. Notes

x 743 in association with viral diseases,

In addition, AN/AD has been reported
seizure disorders, and high fever.
x AN/AD can occur with or without accompanying neurologic disorders.
x Friedrich ataxia, Stevens-Johnson syndrome, Ehlers-Danlos syndrome,
and Charcot Marie-Tooth syndrome are all disorders with peripheral
neuropathies that have been associated with AN/AD.
x Although a complicated perinatal history is common among most patients
with AN/AD, one third of patients have no predisposing factors that led to
the development of AN/AD.

Epidemiology
x Some authors have suggested that the prevalence is 2-15% of children
with known hearing loss.
x In a 2002 review of the prevalence, Sininger suggested that
approximately 1 in 10 children with hearing loss and severely affected
ABR test results have AN/AD.
x Two thirds of the children with auditory neuropathy/auditory
dyssynchrony (AN/AD) demonstrate risk factors associated with perinatal
hearing loss.

History
x AN/AD should be suspected in any child with slightly-to-severely abnormal
hearing thresholds and severe speech and language delay out of
proportion with the presumed hearing loss.
x Most children affected by AN/AD continue to display abnormal pure tone
averages and ABR test results that requires a lifelong commitment by the
child, family, speech pathologist, and audiologist.
x Further evaluation should include auditory brainstem response (ABR) and
optoacoustic emission (OAE) testing to rule out the presence of AN/AD or
other retrocochlear processes.

Diagnostic Considerations
x These include the following:
o Ototoxicity
o Auditory dyssynchrony
o Central auditory processing deficits
o Hyperbilirubinemia

Laboratory Studies
x No hematologic workup is necessary to diagnose auditory
neuropathy/auditory dyssynchrony (AN/AD).
x History and audiologic testing establish the diagnosis

1641
Riyadh et al. Notes

Imaging Studies 744

x Imaging studies are not necessary in the newborn period.
x Once the diagnosis is made correctly, conservative treatment can be
initiated.
x If the parents choose surgical intervention, high-resolution computed
tomography scanning of the temporal bones should be performed.
x This test helps the otologist or neurootologist determine the possibilities
of inner ear malformations that might contribute to the disorder.
x In addition, the inner ear can be visualized and preparations for cochlear
implantation can be made.
x Typically, magnetic resonance imaging (MRI) has no role in AN/AD.

Criteria for the diagnosis of AN/AD:

x All of the following must be present in newborns to diagnose AN/AD:

o Absent or severely abnormal ABR test results at maximal stimulus
(100 dBnHL).
o Normal outer hair cell function as determined by OAEs or CMs
o Absent or elevated stapedial reflex thresholds

x Suspect AN/AD in older children or adults with the following audiologic

findings:
o Pure tone thresholds are abnormal.
ƒ The entire range of abnormalities, from near-normal to
profound, may be seen.
ƒ A more severe loss is usually displayed in the lower
frequency thresholds.
o Poor speech discrimination scores are out of proportion with the
level of loss suspected based on the pure tone average.

x The audiogram findings may vary some, but the overall milieu usually
remains unchanged.

Treatment:
x Treatment of patients with auditory neuropathy/auditory dyssynchrony
(AN/AD) starts with the parents.
x Information should be made available to all parents of children with
hearing loss.
x Once this is done and the condition is thoroughly understood, the proper
supportive adjuvant therapies can begin which include:
o Speech pathology, hearing aid placement, and use of other hearing
devices.

1642
Riyadh et al. Notes

745

x The use of hearing aids can begin with children at around age 3 months.
x Children with AN/AD were once thought not to benefit from hearing aid
amplification; however, recent studies demonstrate that 50% of children
can benefit from placement of an amplification device.
x When children with AN/AD were tested with hearing aids, their speech
discrimination scores improved and were more consistent with the degree
of hearing loss expected via their pure tone audiometry scores.
x The use of hearing aids prior to cochlear implantation is currently
recommended.
x Once the child is aged approximately 6 months, behavior audiometry
thresholds should be obtained.

x Surgical Treatment:
x In 2001, the use of cochlear implantation was expanded to include
children with AN.
x A literature review by Fernandes et al indicated that in children with AN
x spectrum disorder, cochlear implants lead to improvements in hearing
skills similar to those associated with cochlear implants in children with
sensorineural hearing loss.
x Study by Liu et al found that children with AN spectrum disorder who
received cochlear implants prior to age 24 months tended to show better
development of auditory and speech skills than did children who received
the implants at a later age.
x If cochlear implantation fails, another option may exist in AN/AD, with
brainstem implantation having been reported.

1643
Riyadh et al. Notes
746
Physiology of Vestibular System:

- Peripheral Receptors:

- 1. Cristae:
They are located in the ampullated ends of the three semicircular
ducts.
These receptors respond to angular acceleration
All hair cells in each crista are oriented in the same direction

- 2. Maculae
They are located in otolith organs (i.e. utricle and saccule).
Macula of the utricle lies in its floor in a horizontal plane.
Macula of saccule lies in its medial wall in a vertical plane.
They sense position of head in response to gravity and linear
acceleration
Hair cells in the macula oriented in all deferent directions

1644
Riyadh et al. Notes
747
Vestibular Nerve
- Part of VIII cranial nerve
- Mialen sheet covering the part inside the IAC (out side the canal
covered by dura, medial to porus acusticus)

- Vestibular or Scarpa's ganglion is situated in the lateral part of the

internal acoustic meatus.
- It contains bipolar cells.
- The distal processes of bipolar cells innervate the sensory epithelium
of the labyrinth while its central processes aggregate to form the
vestibular nerve

1645
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748
Central Vestibular Connections:

- The fibers of vestibular nerve end in vestibular nuclei and some go to

the cerebellum directly
- Vestibular nuclei are four in number, the superior, medial, lateral
(deiters) and descending (inferior, spinal).
- Afferents to these nuclei come from:

(i) Peripheral vestibular receptors (semicircular canals, utricle and

saccule)
(ii) Cerebellum (some fibers pass directly to it)
(iii) Reticular formation (reticolospinal tract)
(iv) Spinal cord (vestibulospinal tract medial and lateral))
(v) Contralateral vestibular nuclei. (Vestibular commissural system
(contralat discharge rate inhibits ipsilat firing; basis of “push-pull”
connection – paired canals complement one another by canceling out
inherent asymmetries)

(Thus, information received from the labyrinthine receptors is

integrated with information from other somatosensory systems)

1. Cochlear nerve, with its two nuclei. 2. Accessory nucleus. 3. Tuberculum

acusticum. 4. Vestibular nerve. 5. Internal nucleus. 6. Nucleus of
Deiters. 7. Nucleus of Bechterew. 8. Inferior or descending root of
acoustic. 9. Ascending cerebellar fibers. 10. Fibers going to raphé. 11. Fibers
taking an oblique course. 12. Lemniscus. 13. Inferior sensory root of
trigeminal. 14. Cerebrospinal fasciculus. 15. Raphé. 16. Fourth ventricle. 17.
Inferior peduncle. Origin of striæ medullares. (Testut.)

1646
Riyadh et al. Notes
749
- Efferents from vestibular nuclei go to:

(i) Nuclei of CN III, IV, VI via medial longitudinal bundle. It is the

pathway for vestibulo-ocular reflexes and this explains the genesis
of nystagmus.
(Medial longitudinal fasciculus and the ascending tract of
Deiters)
(Correct eye movement & help fixing objects seen in the visual field
when head is rotating)

(ii) Motor part of spinal cord (vestibulospinal fibres). This

coordinates the movements of head, neck and body in the
maintenance of balance.

(iii) Cerebellum (vestibulocerebellar fibres). It helps to coordinate

input information to maintain the body balance.

(iv) Autonomic nervous system. This explains nausea, vomiting,

palpitation, sweating and pallor seen in vestibular disorders (linked to
motion sickness & BP control)
(e.g. Meniere's disease).

(v) Vestibular nuclei of the opposite side.

(vi) Cerebral cortex (temporal lobe). This is responsible for

subjective awareness of motion.

1647
Riyadh et al. Notes
750
Cummings

o The superior vestibular nucleus is involved in VOR pathways. Neurons

in this nucleus fire in relation to eye movements as well as head
movements and a prominent efferent projection of this nucleus is to
the oculomotor nucleus via the medial longitudinal fasciculus. This
tract is particularly important in the control of the VOR
o The lateral vestibular nucleus (of Deiters) can be subdivided on
anatomic and functional grounds into two subnuclei: the dorsal lateral
vestibular nucleus (or Deiters' nucleus) and the ventral lateral
vestibular nucleus
o The dorsal lateral vestibular nucleus give rise to the lateral
vestibulospinal tract, and the ventral lateral vestibular nucleus give
rise to vestibuloocular pathways, the medial vestibulospinal tract, and
vestibulothalamic pathways
o The lateral vestibulospinal tract terminates directly on the ventral horn
cells. This tract is particularly important for vestibulospinal and
vestibulocolic reflexes
o The “rostral” medial vestibular nucleus, like the superior nucleus,
contains many neurons that project to the oculomotor nuclei and
whose firing behavior is related to eye movements
o The medial vestibular nucleus also gives rise to the medial
vestibulospinal tract, which descends in the medial longitudinal
fasciculus to terminate on interneurons in the cervical spinal cord and
ascends to terminate in the eye motor nuclei. This tract is particularly
important for cervicovestibuloocular reflexes
o The inferior (or descending) vestibular nucleus contribute to the
vestibulospinal pathways, but the major projections from this area are
to the cerebellum and reticular formation

1648
Riyadh et al. Notes
751

Figure 139-15 Neural connections in the direct pathway for the VOR from
excitation of the left horizontal canal (left HC). As seen from above, a
counterclockwise head rotation (head) produces relative endolymph flow in
the left HC that is clockwise and toward the utricle. The cupular deflection
excites the hair cells in the left HC ampulla, and the firing rate in the
afferents increases (inset). Excitatory interneurons in the vestibular nuclei
(vest. N.) connect to motor neurons for the medial rectus muscle in the
ipsilateral IIIrd nucleus (III) and lateral rectus muscle in the contralateral
VIth nucleus (VI). Firing rates for these motor neurons increase (bar
graphs). The respective muscles contract and pull the eyes clockwise—
opposite the head—during the slow phases of nystagmus. Inhibitory
interneurons in the vestibular nuclei connect to motor neurons for the
ipsilateral lateral rectus and contralateral medial rectus. Their firing rates
decrease (bar graphs), and these antagonist muscles relax to augment the
eye movement.

1649
Riyadh et al. Notes
752
Vestibular system is conveniently divided into:

(a) Peripheral, which is made up of membranous labyrinth

(semicircular ducts, utricle and saccule) and vestibular nerve.
(b) Central, which is made up of nuclei and fiber tracts in the central
nervous system to integrate vestibular impulses with other systems to
maintain body balance

Semicircular Canals (angular acceleration: head rotation in any direction)

- During rest there is continuous impulses from both sides (200/s)

- At the beginning of rotation endolymph remains stationary due to
inertia
- They respond to angular acceleration and deceleration.
- The one, which lies at right angles to the axis of rotation, is stimulated
the most.
- Thus horizontal canal will respond maximum to rotation on the vertical
axis and so on.
- Due to this arrangement of the three canals in three different planes,
any change in position of head can be detected.
- Constant rates of rotation stimulate the SCC for a maximum 30s after
which the discharge goes down to tonic level
- They detect only beginning of rotation, end of it and any change in
rate of rotation

1650
Riyadh et al. Notes
753
- Stimulation of semicircular canals produces nystagmus and the
direction of nystagmus is determined by the plane of the canal being
stimulated (Thus, nystagmus is horizontal from horizontal canal,
rotatory from the superior canal, and vertical from the posterior canal)

- The stimulus to semicircular canal is flow of endolymph, which

displaces the cupula.
- The flow may be towards the cupula (ampullopetal) or away from it
(ampullofugal), better called utriculopetal and utriculofugal.
- Ampullopetal flow is more effective than ampullofugal for the
horizontal canal.
- The quick component of nystagmus is always opposite to the direction
of flow of endolymph.
(Thus, if a person is rotated to the right for sometime and then
abruptly stopped, the endolymph continues to move to the right due to
inertia (i.e. ampullopetal for left canal), the nystagmus will be
horizontal and directed to the left)

1651
Riyadh et al. Notes
754
Utricle and Saccule (detect static tilt and linear acceleration)

- Utricle is stimulated by linear acceleration and deceleration or

gravitational pull during the head tilts.
- The sensory hair cells of the macula lie in different planes and are
stimulated by displacement of otolithic membrane during the head
tilts. (Horizontal, forward and backward)

- The function of saccule is similar to that of utricle as the structure of

maculae in the two organs is similar but experimentally (he saccule is
also seen to respond to sound vibrations)
(Vertical, forward and backward)

- The vestibular system thus registers changes in the head position,

linear or angular acceleration and deceleration and gravitational
effects.
- This information is sent to the central nervous system where
information from other systems-visual, auditory, somatosensory
(muscles, joints, tendons, skin)-is also received.
- All this information is integrated and used in the regulation of
equilibrium and body posture

- Cerebellum, which is also connected to vestibular end organs further

coordinates muscle movements in their rate, range, force and duration
and thus helps in the maintenance of balance

o Tilt vs. linear acceleration: otoliths alone can’t tell the

difference between linear accelar and tilt up with gravity pulling
down; SCC input helps at high rotational frequency, and other
sensory cues can help (vision); fighter pilots taking off in dark
may perceive linear accelar as tilt up; they may compensate by
nosing the aircraft down, potentially plunging into the water

Maintenance of Body Equilibrium

1652
Riyadh et al. Notes
755
- A useful clinical approach to understand the physiology of equilibrium
is to imagine that the balance system (vestibular, visual and
somatosensory) is a two-sided push and pull system.
- In static neutral position, each side contributes equal sensory
information (push and pull system of one side is equal to that of the
other side)
- If one side pulls more than the other, balance of the body is disturbed.
During movement (turning or tilt, there is a temporary change in the
push and pull system which is corrected by appropriate reflexes and
motor outputs to the eyes (vestibulo-ocular reflex), neck
(vestibulocervical reflex), and trunk and limbs (vestibulospinal reflex)
to maintain new position of head and body, but if any component of
push and pull system of one side is disturbed for a longer time due to
disease, vertigo and ataxia will develop.

Nystagmus:

- A series of jerky oscillatory movements of the eye

- It is a reflex aimed at fixing objects in the visual field during rotation

- 2 components:

1. Slow (in the direction of endolymph) (vestibulo-ocular reflex)

2. Fast (compensatory flick-back movement) (from brainstem)

(The direction of eye movement in nystagmus is identified by the direction of

the fast component)

- During rotation nystagmus in the same direction of the rotation

- When the rotation stop it is in the opposite direction of the rotation

1653
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756
Vertigo and Dizziness

- False sensation of spinning

- Disorientation in space causes vertigo or dizziness and can arise from
disorders of any of the three systems, vestibular, visual or
somatosensory.
- Normally, the impulses reaching the brain from the three systems are
equal and opposite.
- If any component on one side is inhibited or stimulated, the
information reaching the cortex is mismatched, resulting in
disorientation and vertigo.
- The vestibular inhibition on one side (e.g. acute vestibular failure,
labyrinthectomy, Meniere's disease, VIIIth nerve section) causes
vertigo.
- Similarly, stimulation of labyrinth by thermal or rotational stimulus
causes vertigo.
- Dizziness can similarly result from the ocular causes, e.g. high errors
of refraction or acute extraocular muscle paralysis with diplopia.

Motion Sickness

- Nausea, vomiting, pallor and sweating during sea, air, bus or car travel
in certain susceptible individuals characterizes it.
- It can be induced by both real and apparent motion and is thought to
arise from the mismatch of information reaching the vestibular nuclei
and cerebellum from the visual, labyrinthine and somatosensory
systems.
- It can be controlled by the usual labyrinthine sedatives.
- The passenger may feel much better if he/she sits in front seat or
keeps looking out watching the moving visual field

1654
Riyadh et al. Notes
757
Other receptors contributing equilibrium: (visual, vestibural,
somatosensoery)

1. Position in body in relation to space (visual and auditory receptors)

2. Position of various parts of the body
a. Neck proprioception
b. Body proprioception
3. Information concerning the direction of support
(Coetaneous pressure receptors) (eg. Soles of feet)

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Riyadh et al. Notes
758

Evaluation of a Dizzy Patient:

- Three primary sensory inputs responsible for balance:

o Vestibular pathway
o Visual pathway
o Somatosensory (proprioceptive) pathway

- Vestibular labyrinth is divided into:

o Semicircular canals (SCCs):
ƒ Detect angular head movement.
ƒ Produce a compensatory eye movement via
vestibuloocular reflex (VOR) for stabilization of visual
images on the retina and maintenance of acuity during
head movement.
o Otolith organs (utricle and saccule):
ƒ Detect linear acceleration (including gravity).
ƒ Produce compensatory postural changes in response to
transient linear movements and changes via gravity
through vestibulospinal reflex (VSR) pathway.

- Maintenance of balance requires integration of:

o Appropriate detection of environmental sensory inputs
o Accurate CNS integration of all sensory input
o Accurate performance of the correct muscle response for
maintenance of postural control and gaze stability

1656
Riyadh et al. Notes
759
- Dizziness is a term used to describe any of a variety of sensations
that produce spatial disorientation.
- In a majority of dizzy patients, a specific diagnosis may be made by an
adequate history and physical examination.

HISTORY:
- Describe Dizziness:
o Vertigo:
ƒ Illusion of rotational or tilting movement (spinning,
whirling, turning) of the patient or the surroundings.
ƒ In most instances, patients will sense that environment is
in motion around them (objective vertigo).
ƒ Minority of patients feel that they are in motion relative to
a stationary world (subjective vertigo).
ƒ Indicates a problem in the peripheral vestibular system
(labyrinth or CN-8).
o Disequilibrium:
ƒ Difficulty maneuvering within the environment without
experiencing an illusion of motion.
ƒ Sensation of instability of body positions, imbalanced or
fear of falling.
ƒ Symptoms worse while standing or ambulating.
ƒ Indicate CNS, peripheral neuropathic or musculoskeletal
disorders.
o Light-headedness:
ƒ Sense of impending faint or presyncope.
ƒ Indicate migraine, vascular, metabolic, drug-induced,
endocrine or psychogenic causes.
o Oscillopsia:
ƒ Inability to focus on objects with motion, such as reading
a sign while walking,
ƒ Seen with loss of vestibulo-ocular reflex (VOR) in bilateral
vestibular dysfunction.

- Duration of each vertigo attack:

o Lasts for seconds:
ƒ BPPV
o Lasts for minutes to hours:
ƒ Meniere disease
ƒ Vestibular migraine.
o Lasts for days to weeks:
ƒ Vestibular Neuritis
ƒ Labyrinthitis
o Constant vertigo:
ƒ Central vertigo.

1657
Riyadh et al. Notes
760
- Contributing factors:
o Trauma:
ƒ Direct mechanical trauma:
x Head trauma or ear surgery.
x Lead to:
o Labyrinthine concussion
o Temporal bone fracture
o Perilymphatic fistula
o BPPV
ƒ Barotrauma:
x Blast injuries, scuba diving, hyperbaric oxygen
treatments, straining, changes in altitude (airplane
flights or driving in the mountains).

o Infection:
ƒ Recent URTI:
x Vestibular neuritis
ƒ CSOM:
x Labyrinthitis
x Perilymphatic fistula
ƒ Others:
x Herpes zoster oticus (Ramsay Hunt syndrome)
x Otosyphilis
x TB
x HIV
x Lyme disease

o Medical condition:
ƒ Cardiac arrhythmias
ƒ Atherosclerosis
ƒ Anemia
ƒ Hypothyroid
ƒ Diabetes
ƒ Neurological disorders
ƒ Migraine
ƒ Wegener granulomatosis
ƒ Systemic lupus erythematosus

o Medications:
ƒ Topical or systemic ototoxic medications:
x Aminoglycosides, Chemotherapy, Loop diuretics.
ƒ Medications affect blood pressure:
x Diuretics, B-blockers, Calcium channel blockers.
ƒ Medications affect CNS:
x Sedatives, Neuroleptics, Antidepressants.

1658
Riyadh et al. Notes
761
- Aggravating factors:
o Head movement:
ƒ Peripheral vestibular disorders are aggravated by head
movements and gravity.
ƒ Patients are advised to keep their head as still as possible
to avoid sudden movements.
ƒ Examples:
x Posterior canal BPPV:
o Vertigo with rolling over in bed or tilting the
head backward and toward the affected ear.
x Horizontal canal BPPV:
o Vertigo with lying supine and turning the
head to the side.

o Body movement against gravity:

ƒ Rising from a bed or chair.
ƒ Indicates orthostatic hypotension.

o Life style induced:

ƒ Vestibular migraine:
x Food-induced dizziness (caffeine, alcohol, cheese)
x Stress-induced dizziness
x Motion simulation
ƒ Meniere's disease:
x Food induced dizziness (Salt).
ƒ Superior semicircular canal dehiscence:
x Sound-induced vertigo (Tullio phenomenon)
x Pressure-induced vertigo (Hennebert sign)
x Valsalva maneuvers

- Associated symptoms:
o Otological symptoms:
ƒ Meniere's disease:
x Hearing loss, tinnitus and aural fullness.
ƒ SCDS:
x Hearing loss and autophony.

o Migraine symptoms:
ƒ Photophobia, phonophobia and heightened sense of smell.
ƒ Indicates vestibular migraine.

o Neurological symptoms:
ƒ Dysphagia, dysphasia, limb weakness, ataxia and LOC.
ƒ Indicates CNS involvement.

o Psychogenic symptoms:
ƒ Anxiety, panic attacks and agoraphobia.

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762

1660
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763

1661
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764

1662
Riyadh et al. Notes
765

1663
Riyadh et al. Notes
766
PHYSICAL EXAM:

- No clinical test measures directly the function of the

peripheral vestibular system.

- H&N and General Physical Exam:

o General condition and vital signs.
o Neurological and cranial nerve examination.
o Examination for orthostatic hypotension:
ƒ Reduction of systolic BP > 20 or diastolic BP >10
within 3 minutes of standing.
- Otoscopy:
o Inspection of TM:
ƒ AOM, OME, CSOM or masses.
o Pneumatoscopy:
ƒ Fistula test:
x Induce nystagmus by applying intermittent
pressure on tragus or by using Pneumatic
Otoscopy.
x Normally, the test is negative because the
pressure changes in EAC cannot be transmitted
to the labyrinth.
x Positive Fistula Test:
o Nystagmus to same side (irritatve).
o Indicates:
ƒ Perilymph fistula (50%).
ƒ SCDS
x False Positive Fistula Test (Hennebert’s
sign):
o Nystagmus to same side (irritatve) in the
absence of Perilymph fistula.
o Indicates:
ƒ Meniere's disease (25%) due to
fibrous bands connecting utricular
macula to the stapes footplate.
ƒ Congenital syphilis due to
hypermobility of stapes footplate.
- Tuning fork examination:
o 512-Hz fork:
ƒ Auditory stimulus for Weber and Rinne testing.
ƒ Tullio Phenomenon:
x Noise-induced vertigo and nystagmus in
perilymphatic fistula or SCDS.
o 256-Hz fork:
ƒ Malleolar test:
x Patient can perceive sound in affected ear while
the fork is placed on the ankle due to “third-
window effect” in perilymphatic fistula or SCDS.

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- Bed side vestibular tests:
1. Nystagmus:
1. Spontaneous Nystagmus
2. Gaze-Evoked Nystagmus
3. Saccades
4. Smooth Pursuit
2. Head Thrust (Impulse) Test
3. Head Shake (Heave) Test
4. Dix-Hallpike Maneuver
5. Limb Coordination Tests
6. Fukuda Stepping Test
7. Tandem Romberg Test
8. Gait Test
9. Hyperventilation Test

- Nystagmus:
o Rapid involuntary oscillatory movement of the eyes.
o Results from imbalance between the bilateral vestibular system.
o Direction of nystagmus:
ƒ Slow phase is the pathologic component.
ƒ Determined by the corrective fast phase.
o Types of nystagmus:
ƒ Irritative Nystagmus:
x Nystagmus beating toward the affected ear.
x Due to increased excitability of vestibular system at
the affected ear.
x Examples:
o Perilymphatic fistula
o Serous labyrinthitis
o Post-stapes surgery
ƒ Paralytic Nystagmus:
x Nystagmus beating away from affected ear.
x Due to decreased excitability of vestibular system
at the affected ear.
x Examples:
o Ménière’s disease, vestibular neuronitis
o Suppurative labyrinthitis
o Dead ear
o Alexander's Law:
ƒ Peripheral nystagmus will increase when gaze is in the
direction of fast phase, and will decreased when in the
direction of slow phase.
o Ewald's Law:
ƒ Peripheral nystagmus is in the plane of SCC being
stimulated and its direction (fast phase) is opposite to the
direction of endolymphatic flow.
ƒ Stimulating/excitatory response are greater than
inhibitory response.

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o Fixation suppression:
ƒ Peripheral nystagmus is suppressed with visual fixation.
ƒ Absence of suppression suggests central lesion.
ƒ Suppression can be prevented by:
x Frenzel glasses.
x Darkness.

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- Vestibulo-Ocular Reflex (VOR):
o Head rotation in a plane results in equal but opposite eye
rotation to allow retina to maintain fixation on an object.
o Head motion 10° to left produces eye movement 10° to right.

- Vestibulospinal Reflex:
o Otolith organs modulate the anti-gravitational muscles in a
similar way as VOR modulates the eye to allow for postural
control and position (simultaneous contraction of extensor
muscles with contralateral flexor muscles to maintain posture).
o Motion of muscles and joints may also modify the
vestibulospinal reflex via receptors found in intervertebral joint
receptors (upper cervical).

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- Spontaneous Nystagmus:
- Nystagmus present without visual or vestibular stimulation.
- Important sign in the evaluation of vestibular system.
- Method:
o Patient is seated in upright position and fixates on a stationary
target with best-corrected vision (with glasses if applicable).
o Eyes are observed for nystagmus with Frenzel glasses.
o If nystagmus was observed, the following characteristics should
be noted:
ƒ Nystagmus waveform:
x Jerk nystagmus (slow and fast phase).
x Pendular nystagmus (equal movement).
ƒ Type:
x Horizontal
x Vertical
x Torsional
ƒ Direction:
x Right
x Left
x Up-beating
x Down-beating
ƒ Effect of fixation:
x Suppressed
x No affected
ƒ Effect of gaze (degree of nystagmus):
x Increased
x Decreased
- Interpretation:
o Peripheral vestibular pathology:
ƒ Jerk nystagmus.
ƒ Fixed direction.
ƒ Horizontal or torsional.
ƒ Enhanced with:
x Frenzel glasses.
x Gazing in the direction of fast phase.
ƒ Suppressed with:
x Visual fixation.
x Gazing in the direction of slow phase.

o CNS pathology:
ƒ Jerk or pendular nystagmus.
ƒ Direction-changing.
ƒ Pure vertical or torsional.
ƒ No suppressed visual fixation.
ƒ Not affected by gazing in different directions.

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- Gaze-Evoked Nystagmus:
- Abnormal persistent nystagmus that present with eye gazing between
0-30q from midline.
- End-point nystagmus is a transient NORMAL gaze-evoked nystagmus
that present with gaze > 30q from midline.
- Method:
o Patient is seated in upright position and fixates on a stationary
target with best-corrected vision (with glasses if applicable).
o Examiner keeps his finger about 30 cm from the patient's eye.
o Examiner moves his finger in the horizontal plane and then in
vertical plane, for 10-20 seconds in each position.
o Examiner should NOT move more than 30° from the midline.
o Eyes are observed for nystagmus with Frenzel glasses then to
fixate on the examiner's fingertip.
- Interpretation:
o Peripheral vestibular pathology:
ƒ Jerk nystagmus.
ƒ Fixed direction.
ƒ Horizontal or torsional.
ƒ Enhanced with:
x Frenzel glasses.
x Gazing in the direction of fast phase.
ƒ Suppressed with:
x Visual fixation.
x Gazing in the direction of slow phase.
ƒ No Rebound nystagmus.
o CNS pathology:
ƒ Jerk or pendular nystagmus.
ƒ Direction-changing.
ƒ Pure vertical or torsional.
ƒ No suppressed visual fixation.
ƒ Not affected by gazing in different directions.
ƒ Presence of Rebound nystagmus:
x After holding the gaze for 30 seconds toward the
direction of fast phase, reversed fast-phase
direction rebound nystagmus occurs after eye is
returned to primary position.
o Brun nystagmus:
ƒ Combination of central and peripheral Gaze-Evoked
Nystagmus.
ƒ Due to large CPA tumors compressing ipsilateral
cerebellar flocculus.
ƒ If right CPA tumor:
x Right-beating central nystagmus with right gaze
(toward the lesion).
x Left-beating vestibular nystagmus with left gaze
(away from the lesion).

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- Saccades:
- Allow rapid shifting of gaze from one object to another, maintaining
the target image on the fovea.
- Abnormalities in saccadic eye movements may be difficult to detect in
clinic examination and may require videonystagmography (VNG).
- Method:
o Patient is asked to alternately fixate with the head still, on the
examiner’s nose and then on the finger held at 15° away from
the primary position.
o Repeat it in right and left horizontal plane and up and down in
vertical plane.
o Saccadic eye movement are observed for:
ƒ Latency of initiation.
ƒ Dysmetria (inaccurate saccades):
x Hypometria (undershooting).
x Hypermetria (overshooting).
- Interpretation:
o Peripheral vestibular pathology:
ƒ Normal saccadic eye movement.
o CNS pathology:
ƒ Abnormal saccadic eye movement.

- Smooth Pursuit:
- Visual ocular fixation and tracking of moving objects, maintaining the
target image on the fovea.
- Requires intact central optic tracts.
- Method:
o Patients is asked to track the examiner index finger that is
initially positioned directly in front of the patient and moved
smoothly 30° per second in horizontal then vertical planes.
o Testing area is restricted 30° to left, right, up, and down from
neutral position to avoid provoking normal end-gaze nystagmus.
o Repeated 3-5 times in each plane.
o Smooth pursuit eye movement are observed for:
ƒ Catch-up saccades.

- Interpretation:
o Peripheral vestibular pathology:
ƒ Normal smooth pursuit.
o CNS pathology:
ƒ Abnormal smooth pursuit.

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Riyadh et al. Notes
774

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Riyadh et al. Notes
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- Head Thrust (Impulse):
- Used to detect asymmetries in vestibular gain from SSCs.
- Can be performed in all three canal pair orientations.
- In patients with unilateral vestibular loss:
o VOR cannot produce signals to ocular muscles for eye
stabilization during passive angular head rotations.
o Brain will generate a re-fixation saccade toward the involved ear
to acquire a visual target.
- Method:
o Patient is asked to fixate on examiner’s nose.
o Patient’s head is impulsively and unpredictably moved 30° from
the midline in one direction.
ƒ To test Horizontal SSC:
x Head is first tilted forward 30°.
x Head is thrusted to examined side in horizontal
plane.
ƒ To test Superior SSC:
x Head is first turned 45° away from examined side.
x Then it is thrusted downward.
ƒ To test Posterior SSC:
x Head is first turned 45° toward the examined side.
x Then it is thrusted upward.
o Eye movement are observed for:
ƒ Corrective saccades.

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- Interpretation:
o Peripheral vestibular pathology:
ƒ Corrective saccade in opposite direction to the head
movement.
o CNS pathology:
ƒ No corrective saccade.

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- Head Shake (Heave):
- Used to detect utricular dysfunction by evaluating asymmetry in VOR.
- Method:
o Patient is asked to fixate on examiner’s nose with Frenzel
glasses in place.
o Patient’s head is shake back and forth as quickly as possible in
the horizontal plan for a period of 30 seconds.
o Head shaking is stopped abruptly and the examiner looks for
any nystagmus.

- Interpretation:
o Peripheral vestibular pathology:
ƒ Horizontal nystagmus away from the affected side (due to
unopposed stimulation of the intact labyrinth).
o CNS pathology:
ƒ Vertical nystagmus.
ƒ Prolonged nystagmus.

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- Dix-Hallpike Maneuver:
- Standard clinical test for PC-BPPV.
- Allows maximal stimulation of posterior SCC.
- The test for BPPV can be made more sensitive by having the patient
wear Frenzel glasses.
- Method:
o Patient is seated on the exam table.
o To test the Right Posterior SCC, examiner holds the patient's
head, turns it 45° to the right and then places the patient in a
supine position so that his head hangs 30° below the horizontal.
o Patient's eyes are observed for nystagmus or complaint of
vertigo.
o The test is repeated with head turned to left and then again in
straight head-hanging position.
- Interpretation:
o Peripheral vestibular pathology (PC-BPPV):
ƒ Torsional nystagmus
ƒ Beating toward the stimulated ear (downward
ear/geotropic)
ƒ Appears after latency period of 2-20 seconds.
ƒ Lasts 15-45 seconds (< 1 minute)
ƒ Fatigable (disappears with repeated testing).
ƒ Associated sometime with vertigo.
o CNS pathology:
ƒ Direction-changing nystagmus
ƒ No latency
ƒ Prolonged lasting > 1 minute
ƒ Not fatigable

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- Limb Coordination:
- Evaluate central lesions of the cerebellum and brainstem.
- Method of Finger-Nose-Finger Test:
o Patient is asked to alternate touching the examiner's finger and
his own nose.
o As the patient touches his nose, the examiner quickly moves
their finger to a new horizontal position.
o Examiner observes for any dysmetria.
- Method of Hand Rapid Alternating Movement Test:
o Patient is asked to alternate hand pronation and supination by
tapping back of the hand on the thigh and then front of the
hand on the thigh in a rapid succession.
o Examiner observes for any dysdiadochokinesia.
- Method of Heel-To-Shin Test:
o Patient is asked to fully extend their right leg and place their
heel on the floor.
o Then smoothly moves the heel of the left foot along the shin of
extended right leg.
o The test is repeated with the left leg extended.
o Examiner observes for any dysmetria.
- Interpretation:
o Peripheral vestibular pathology:
ƒ Normal tests.
o CNS pathology:
ƒ Abnormal tests (dysmetria or dysdiadochokinesia) in
cerebellar pathology.

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- Fukuda Stepping Test:
- Used to evaluate the vestibulospinal function.
- Normal subjects deviate <30° to one side during the stepping test.
- Method:
o Patient is asked to march in place with eyes closed and arms
extended straight out at the level of shoulders for 1 minute.
o Examiner evaluates degree of lateral rotation at the end of the
maneuver.
- Interpretation:
o Peripheral vestibular pathology:
ƒ Unilateral Non-compensated:
x Deviation >30° to the affected side.
ƒ Unilateral Compensated:
x Normal test.
o CNS pathology:
ƒ Patient will be imbalanced even with eyes opened in
cerebellar pathology.

- Tandem Romberg Test:

- Used to evaluate the somatosensation and proprioception function.
- More sensitive than Romberg test (standing with feet together) to
detect vestibular pathology.
- With the eyes open, patient can still compensate the imbalance.
- With eyes closed, vestibular system is at more disadvantage.
- Method:
o Patient is asked to stand with one heel in front of toes and arms
extended by the sides with eyes first open and then closed.
o Examiner observes the side of sway (if any) in both situations
with and without vision.
- Interpretation:
o Peripheral vestibular pathology:
ƒ Sway to the affected side with
eye closed.
o CNS pathology:
ƒ Patient will be imbalanced even
with eyes opened in cerebellar
pathology.

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- Tandem Gait:
- Used to evaluate the somatosensation and
proprioception function.
- Method:
o Patient is asked to walk along a straight
line to a fixed point in a heel to toe
manner, first with eyes open and then
closed.
- Interpretation:
o Peripheral vestibular pathology:
ƒ Sway to the affected side with eye
closed.
o CNS pathology:
ƒ Patient will be imbalanced even
with eyes opened in cerebellar
pathology.

- Hyperventilation Test:
- Hyperventilation decreases serum PC0 2 levels leading to:
o Cerebrovascular vasoconstriction:
ƒ Leads to lightheadedness and tingling of hands and lips.
ƒ Reproduce symptoms of hyperventilation syndrome or
anxiety.
o Elevation of blood pH (Alkalosis):
ƒ Leads to improved axonal conduction in partially
demyelinated nerve fibers.

- Method:
o With Frenzel glasses in place, patient is asked to hyperventilate
for 90 seconds by taking deep breaths and then inhaling and
exhaling in rapid succession.
o Patient is evaluated for dizziness, light-headedness or
nystagmus.

- Interpretation:
o Peripheral vestibular pathology:
ƒ Demyelination of CN-VIII (Acoustic schwannoma):
x Induce excitatory nystagmus to the affected side.
o CNS pathology:
ƒ Psychiatric disorders (Anxiety and panic attacks):
x Induce dizziness and light-headedness.
ƒ Central Demyelination (Multiple sclerosis):
x Induce nystagmus.

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Laboratory Test:
- Requested if the diagnosis is unclear after evaluation by history,
physical, and the above mentioned screening tests.
- Includes:
1. Electronystagmography (ENG)/ Videonystagmography (VNG)
2. Rotational Chair Testing
3. Posturography
4. Vestibular Evoked Myogenic Potentials (VEMP)

Electronystagmography (ENG)/ Videonystagmography (VNG):

- Most widely used vestibular tests.
- Relies on the vestibulo-ocular reflex (VOR)
- Tests the peripheral vestibular function and its ability to generate
efficient voluntary eye movements necessary for maintaining visual
contact with the environment.
- Provides information regarding localization of lesion.
- Dependent on Anatomy of ear canal and temporal bone.
- Difficult to perform in children.
- Well-tolerated.
- Does not correlate with function.
- Consists of 3 Subtests:
1. Oculomotor tests.
2. Positional and positioning tests.
3. Caloric tests.

- Two methods to measure eye movements:

1. Electronystagmography (ENG):
o ENG record eye movements by recording changes in the
corneoretinal potential by placing electrodes around the eyes:
ƒ Cornea is (+ve) and Retina is (–ve).
o Advantages:
ƒ Low cost; easy; noninvasive; no head restraint needed;
lots of experience interpreting data.
o Disadvantages:
ƒ Signal susceptible to changes in skin resistance due to
perspiration; eye blink artifacts; poor signal:noise ratio.

2. Videonystagmography (VNG):
o VNG record eye movements with small cameras in goggle set.
o Eyes illuminated with near-infrared light – camera sees the pt
but the pt doesn’t see the camera.
o Advantages:
ƒ No artifact; no need to recalibrate; no need for
impedance testing; vertical and torsional movements
more easily assessed; disconjugate eye movements more
easily seen; portable unit for testing off-site
o Disadvantages of VOG:
ƒ must wear goggles; expensive

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x Oculomotor Testing
- The common thread of these tests is they all test eye movements that
originate in the cerebellum.
- Abnormalities in these tests suggest a Central neurological origin.

1. Spontaneous nystagmus and fixation Tests:

o Spontaneous nystagmus may be observed with eyes centered
and head upright and asking the patient to visually fixate on an
object which is then followed by loss of fixation (ie. close eyes,
turn lights off, or use Frenzel lenses).
o Nystagmus due to peripheral lesions usually decreases with
fixation (Fixation suppression).

2. Gaze-evoked nystagmus:
o Induced by having the subject gaze 20-30 degrees to the left
and right of center for 30 seconds each
o Maybe done with or without fixation.

3. Rebound nystagmus:
o Occur after prolonged gaze holding after the eye is returned to
primary position.

4. Saccadic System:
o Saccades allow rapid shifting of gaze rapidly from one object to
another, maintaining the target image on the fovea.
o Used to move a target from retinal periphery into fovea
o Tested by presenting targets at 10-20 degrees right and left of
center gaze, Patient asked to rapidly shift gaze to each target.
o Evaluate Central components of the vestibular system;
cerebellar or brainstem injury may cause ocular dysmetria
(overshooting or undershooting of eye rotation).

5. Pursuit System:
o Allows ocular fixation on moving objects and maintains target
image on the fovea.
o Tested with Sinusoidal-Tracking Tests by having the patient
follow a spot moving in a sinusoidal pattern.
o At faster speeds the eyes may not be able to “keep up” causing
saccadic eye jerks.
o Saccadic eye jerks at low velocity (rotational frequencies <0.1–
0.3 Hz or target velocities <30°/s) suggests a Central
pathology.

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6. Optokinetic System:
o Allows fixation on a moving field.
o Maintains image on the whole retina rather than specifically on
the fovea as in saccades and pursuit systems
o Tested clinically by having the patient stay still and moving the
environment (a series of black and white stripes on a moving
field that encompasses the whole field of vision).
o Brainstem disease may cause bilateral reduced gain, cerebellar
lesions may induce ataxia, peripheral lesions may demonstrate
asymmetry.
o Not often used clinically

x Positional/Positioning Nystagmus Testing

- Abnormalities in these tests suggest a Vestibular lesion.
- Determine whether the vestibular system responds normally and
symmetrically to changes in head position.
- When placed in different positions, dizziness and nystagmus may occur
as a result of incomplete compensation in that particular position.
- Patients with dizziness and NO nystagmus provoked by different
positions must have non-vestibular etiologies considered.
- Vertical nystagmus or multidirectional nystagmus is highly suggestive
of central disorders.
- Used to determine the presence of BPPV.
- BPPV is most commonly the result of otoliths in the posterior SCC.
- Stimulation using the Dix-Hallpike maneuver commonly causes
torsional nystagmus which is difficult to measure if traditional ENG is
used.
- It is important to note that patients may fatigue the response, and
patients with true BPPV may test negative on the initial visit.
- It is therefore important in both ENG testing and clinical testing that
patients with a strong history of BPPV be tested on multiple occasions
using the Dix-Hallpike maneuver.

- Positional Testing:
• Tests for nystagmus evoked by a new static head position
(positional nystagmus is maintained as long as head remains in
the evoked position).

- Positioning Testing:
• Tests for nystagmus evoked by the action of motion of the head
• Most common is Dix-Hallpike.

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x Caloric Testing:
- Gold standard study for detecting unilateral vestibular loss.
o Only test that evaluates vestibular function in each ear
independently.
o Determines right, left or bilateral vestibular weakness.
- The basis of this test is to induce nystagmus by thermal stimulation of
the vestibular system.
- In case of TM perforation, Air should be used instead of water.
- Method:
o In supine position, Head is elevated 30° to bring the horizontal
SCC into a vertical position.
o 250 cc of warm and cold water or air is then flushed into the
external auditory canal at 7 degrees above (44C) or below
(30C) body temperature for 40 seconds.
o Nystagmus is recorded with eyes open and closed.
o Time taken from the start of irrigation to the end point of
nystagmus is recorded and charted on a calorigram.
o If no nystagmus is elicited from any ear, test is repeated with
water at 20°C for 4 minutes before labelling the labyrinth dead.

- Varying temperature causes a non-physiologic stimulation of one

labyrinth that may evoke vertigo, nystagmus, and occasionally nausea
and vomiting.

- Cold water or air (30° C) to Right Ear with patient in upright

position causes flow in the Ampullfugal direction which Decreases the
electrical activity of the ipsilateral vestibular nerve with a
corresponding Increase in electrical activity of the opposite vestibular
nerve resulting in Left-Beating Nystagmus.

- Warm water or air (40° C) to Right Ear with patient in upright

position causes flow in the Ampullpetal direction which Increase the
electrical activity of the ipsilateral vestibular nerve with a
corresponding Decreases in electrical activity of the opposite vestibular
nerve resulting in Right-Beating Nystagmus.

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- COWS:
o “Cool Opposite, Warm Same”
o Represents the direction of nystagmus with warm and cool
water.
o Fast phase away from or toward the irrigated ear.
o Cold irrigation is an inhibitory stimulus, and warm irrigation is
excitatory.
o Warm water causes the perilymph to rotate towards the ampula,
resulting in stimulation of the ipsilateral labyrinth and a drift of
the eyes away from the stimulated side. The eyes compensate
with a saccade toward the stimulated side.
o The opposite occurs with cold water stimulation.

- Maximum Slow Phase Velocity:

o Determined by dividing the duration by the amplitude of the
slow phase.
o Standard measure of caloric response intensity.

- Directional Preponderance:
o Denotes that the nystagmus response in a particular direction is
weaker than the evoked response in the opposite direction.
o Determined by comparing the duration or velocity of Right-
beating nystagmus from both ears with Left-beating nystagmus
from both ears.

- Unilateral Caloric Weakness:

o Denotes that the response of one side to a stimulus is reduced
in comparison to the other side.
o Determined by comparing the duration or velocity response
from left and right ears.
o > 20–25% difference between sides suggest a unilateral
peripheral weakness:
o Seen in Meniere's disease, acoustic neuroma, post-
labyrinthectomy or vestibular nerve section.

- Bilateral Weakness:
o Suggested when the total caloric maximum slow phase velocity
from each ear (all 4 irrigations) is Less than 12–24°/second.

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Riyadh et al. Notes
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Central v. Peripheral Findings on ENG

Findings suggestive of a central disorder

1. Spont or positional nystagmus with normal calorics
2. Direction-changing nystagmus independent of
stimulus change
3. Failure of fixation suppression
4. Bilat reduced or absent calorics without history of
labyrinthine or middle ear disease
5. Abnormal saccade/pursuit results (esp if calorics N)
6. Hyperactive caloric responses

Findings suggestive of a peripheral disorder

1. Unilateral caloric weakness
2. Bilat caloric weakness with a Hx of labyrinthine
disease or ototoxic drug use
3. Fatiguing positional nystagmus
4. Intact fixation suppression response
5. Direction-fixed nystagmus

Rotational Chair Testing

- Gold standard study for detecting bilateral vestibular loss
- Sinusoidal (slow) Harmonic Acceleration Test.
- Test SCC under higher frequency conditions than caloric test.
- Evaluates the vestibulo-ocular reflex.
- Method:
o Patient is seated in the chair, eye movements are recorded
while patient (chair) is rotated along the horizontal plane.

- Vestibulo-ocular reflex measurements:

1. Gain:
- Ratio of slow phase eye velocity to chair (head) velocity)
- Normal gain is 1.
- Low gain: Poor attention or testing conditions.
- Low gain in ideal conditions: Bilateral loss.
- High gain: Cerebellar lesion minimizing inhibition
2. Phase:
- Compares peak responses of the slow component of the eye
velocity with the maximum velocity of the chair (head).
- Determines the timing relationship between stimulus and
response.
3. Symmetry:
- Compares eye movement during rightward chair rotation Vs.
eye movement during leftward chair rotation.
- Normally should be completely symmetric.

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789
- Indications:
1. Bilateral vestibular dysfunction. (Procedure of choice)
2. Mild vestibular dysfunction undetected by traditional ENG testing.
3. Identify residual labyrinthine function in those with no calorics.
4. Monitor changes in vestibular function over time.
5. Follow progress of vestibular compensation.

- Abnormalities are primarily seen at low frequencies (abnormal phase

- and gain reduction) and high frequencies (asymmetry)
- Normal vestibulo-ocular response results in similar slow eye phase
- velocity and chair velocity.
- Acute unilateral peripheral lesions typically reveal low frequency phase
leads and high frequency asymmetry (the absence of asymmetry
suggests vestibular compensation, eg, vestibular schwannoma)
- Bilateral vestibular disease typically demonstrates reduced gain at low
frequencies but normal gain at high frequencies.

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Riyadh et al. Notes
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Posturography:
- ENG and rotational chair testing are designed to evaluate the
horizontal VOR by stimulating the horizontal semicircular canals.
- Posturography evaluates other components of balance.
- Measures postural stability while variably changaing the visual field
references and support structures.
- Evaluates Spinal/proprioceptive, visual, and vestibular systems
- Method:
o Patients tries to maintain balance on a level platform with eyes
open, eyes closed, and with stimulated moving visual
environment.
o Test is then repeated on a physically swaying platform.
- Balance requires cerebellar integration of the information from
vestibular, visual and somatosensory organs.
- Dysfunction of any of the necessary components of balance results in
stronger reliance on other peripheral sensors for maintenance of
balance.
- Posturography systematically takes away one or more sensory
components to evaluate which component the patient is reliant upon
for balance.
- This is accomplished through one of six conditions:
1. Condition One:
o Stable platform with eyes open in a stable visual environment
(patient has full use of all information: visual, vestibular, and
somatosensory).
2. Condition Two:
o Stable platform with eye closed (patient must rely on vestibular
and somatosensory information)
3. Condition Three:
o Stable platform with moving visual surroundings (patient must
suppress a false sense of visually induced movement and rely
on vestibular and somatosensory inputs).
4. Condition Four:
o Unstable platform with eyes open in a stable visual environment
(patient must rely on vestibular and visual inputs)
5. Condition Five:
o Unstable platform with eyes closed (patient must rely on
vestibular input only because visual and somatosensory
feedback have been eliminated)
6. Condition Six:
o Unstable platform and unstable visual environment (patient
must rely on vestibular input alone and suppress a false sense
of visually induced movement.

- Controversial applications in diagnosis (Non-specific).

- Indications:
1. Confirm malingering.
2. Monitor progress in vestibular rehabilitation.

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Riyadh et al. Notes
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Vestibular Evoked Myogenic Potential (VEMP)
- Cervical VEMP (cVEMP)
o Provide 95 dB auditory click stimulation, gauge EMG response in
ipsilateral sternocleidomastoid muscle.
o Measures sacculocolic reflex.
o Pathway:
ƒ Acoustic signal > saccule > inferior vestibular nerve >
vestibular nucleus > vestibulospinal tract >
sternocleidomastoid muscle action potential.
o Indications:
ƒ Ménière’s disease (increase threshold)
ƒ Inferior vestibular nerve lesion (increase threshold)
ƒ SCDS (decrease threshold)

- Ocular VEMP (cVEMP)

o EMG response of contralateral ocular muscles in response to
bone conducted vibration or air conducted sound.
o Air conduction elicits contralateral response, bone conduction
elicits bilateral responses (represents vestibulo-ocular pathway)
o Pathway:
ƒ Acoustic signal > utricle > superior vestibular nerve >
contralateral inferior oblique (for air conduction) or
bilateral response (for bone vibration).
o Superior vestibular neuritis causes absent/reduced oVEMP but
no effect on cVEMP.

1690
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793
Management Concepts of Dizzy Patient:
1. Safety:
o Avoid heights, ladders, driving, operating heavy machinery
2. Acute Vestibular Suppression:
o Indicated for intolerable symptoms.
o May delay central compensatory mechanisms in the long term.
o Common medical therapies:
o Betahistine ( Betaserc 24,16,8 mg , Maximum 48mg/day).
o Phenothiazine
o Meclizine
o Diazepam
o Scopalmine
o Antiemetics
o Corticosteroid.
3. Vestibular Rehabilitation:
o Indicated for chronic complaints.
o Consists of a series of positional tasks, head movements, and
oculomotor exercises to facilitate central compensation
4. Surgical Management:
o Indicated for specific diagnoses

1691
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794

Disorders of Vestibular System:

Disorders of vestibular system cause vertigo and are divided into:

- Peripheral:
o Responsible for 85% of all cases of vertigo.
o Involve vestibular end organs and their first order neurons.
ƒ Inner ear or the CN V-III nerve pathology.
o CNS compares the input that comes from each ear:
ƒ When inputs are symmetric, the system is balanced and
no sense of movement is felt
ƒ When inputs are asymmetric, CNS interprets this as a
head rotation and generates compensatory eye
movements and postural adjustments leading to vertigo.
o In healthy individual, CNS compensation occurs after several
days and results in near-normal clinical recovery, even if
complete unilateral vestibular loss has occurred.

- Central:
o Involve central nervous system after the entrance of vestibular
nerve in the brainstem and involve vestibulo-ocular, vestibulo-
spinal and other central nervous system pathways.

1692
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795

1693
Riyadh et al. Notes
796

1694
Riyadh et al. Notes
797
Peripheral Vestibular Disorders:

Benign paroxysmal positional vertigo (BPPV):

- Most common cause of peripheral vertigo disorder.

o 40% of patients with peripheral vestibular vertigo.
- Characterized by brief spells of severe vertigo after specific
movements of the head.
- Incidence increases with age with mean age of onset is 40-50s.
- About 1/3 of patients have a recurrence in the first year after
treatment, and by five years, 50% of all patients have a recurrence.

- Pathophysiology:
1. Canalithiasis theory:
ƒ Most accepted theory.
ƒ Free-floating otoconia (calcium carbonate particles from
utricle) is dislodged and migrate to the endolymph of SCC
as a result of head movement in a specific position.
ƒ The inertial drag of the endolymph causes displacement
of the cupula resulting in latent vertigo which resolves
when the debris settles.
2. Cupulolithiasis theory:
ƒ Dislodged otoconia adheres to the cupula of the
semicircular canal resulting in an ampulla that is gravity
sensitive.
ƒ Objections to theory include no account for the transient
nature of vertigo and the torsional nystagmus exhibited in
BPPV.

- Types of BPPV:
o Posterior canal BPPV (PC-BPPV): 90%
ƒ Most common SCC affected because it is the lowest SCC
when head is upright.
ƒ Vertigo occurs after:
x Rolling over in bed
x Extreme head extension while looking up
ƒ Rare to be bilateral (5%).
o Lateral canal BPPV (LC-BPPV): 10%
ƒ Most commonly induced by the repositioning maneuver
for PC-BPPV (Epley maneuver).
ƒ Involved side is usually the same side of PC-BPPV.
ƒ Vertigo occurs after:
x Turning the head to either side in bed.
ƒ Otoconia in lateral canal tend to fall out spontaneously
with no treatment.
o Superior canal BPPV (SC-BPPV): 2%
ƒ Otoconia in superior canal tend to fall out spontaneously
with no treatment.

1695
798
Riyadh et al. Notes
799
- Causes of BPPV:
o Idiopathic (50%):
ƒ Most common cause.
ƒ No known cause was identified.
o Head injury:
ƒ Most common known cause.
o Viral infection:
ƒ Vestibular neuronitis.
ƒ Labyrinthitis.
o Surgery:
ƒ Stapedectomy.
o Prolonged bed rest:

- Clinical features:
o Typically self-limiting.
o Recurrent episodes of:
ƒ Brief (lasting seconds).
ƒ Positional vertigo (turning over in bed, getting up, turning
the head, bending over, looking up).
ƒ May be associated with nausea and prolonged light-
headedness.
o No associated hearing loss or other neurologic symptoms.

- Diagnosis of BPPV:
o Positioning Maneuvers:
ƒ Dix-Hallpike Maneuver:
x Standard clinical test for PC-BPPV.
x Allows maximal stimulation of posterior SCC.
x The test for BPPV can be made more sensitive by
having the patient wear Frenzel goggles or a video
goggle.
x Method:
o Patient is seated on the exam table.
o To test the Right Posterior SCC, examiner
holds the patient's head, turns it 45° to the
right and then places the patient in a supine
position so that his head hangs 30° below
the horizontal.
o Patient's eyes are observed for nystagmus or
complaint of vertigo.
o The test is repeated with head turned to left
and then again in straight head-hanging
position.

1696
Riyadh et al. Notes
800

- Classic features of nystagmus in PC-BPPV:

1. Torsional nystagmus
2. Beating toward the stimulated ear (downward ear/geotropic)
3. Appears after latency period of 2-20 seconds.
4. Lasts 15-45 seconds (< 1 minute)
5. Fatigable (disappears with repeated testing).
6. Associated sometime with vertigo.

1697
Riyadh et al. Notes
801

ƒ Supine Roll Maneuver:

x Standard clinical test for LC-BPPV.
x Allows maximal stimulation of Lateral SCC.
x Method:
o Patient is seated on the exam table.
o Patient is placed in a supine position with
head resting on exam table (not
hyperextended).
o Head is then turned rapidly to right so the
patient’s right ear rests on the table.
o Eye movements are monitored with Frenzel
glasses for 30 seconds.
o Patient’s head is then returned back to
supine position (looking upward).
o Head is then turned rapidly to left so the
patient’s left ear rests on the table.
o Eye movements are monitored again.
o Which one is the bad ear?
ƒ The side that when placed down,
elicits greater symptomatic
complaints and nystagmus
amplitude.

- Classic features of nystagmus in LC-BPPV:

1. Horizontal nystagmus
2. Geotropic (most commonly) or ageotropic.
3. Shorter latency period than in PC-BPPV.
4. Less fatigable then in PC-BPPV.

1698
Riyadh et al. Notes
802
o Rotatory chair test:
ƒ Indications:
x Diagnose and treat patients with spine
abnormalities who can’t tolerate manual
manipulation.
x Diagnose and treat patients with more difficult
cases of BPPV (Bilateral or lateral BPPV).

- Treatment of BPPV:
o In-Office Re-Positioning Maneuvers:
ƒ Based on repositioning free floating particle (otoconial
debris) from involved SCC back into the utricle.
ƒ Maneuvers for treating PC-BPPV:
1. Epley’s Maneuver:
o Simple and effective to treat PC-BPPV.
o 80% of patients will be cured by a single
maneuver.
o If the patient remains symptomatic, the
maneuver can be repeated.
o Method:
ƒ Starting with Dix-Hallpike position to
the affected side.
ƒ Wait till vertigo and nystagmus
subside.
ƒ Head is turned 90 degree and wait till
vertigo and nystagmus subside.
ƒ Head and body are turned 90 degree
more in lateral recumbent position so
that affected ear is up.
ƒ Patient is then brought to upright
sitting position.

1699
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803

1700
Riyadh et al. Notes
804
2. Semont Maneuver:
o Effective to treat PC-BPPV.
o More difficult compared to Epley maneuver.
o Method for treating Left PC-BPPV:
ƒ Patient is setting in upright position
with head is turned 45 degree to the
affected side (left).
ƒ Patient is then turned into right lateral
recumbent position while maintaining
this head position (looking upward)
and remains for 4 minutes.
ƒ Patient is then rapidly moved 180
degree into left lateral recumbent
position while maintaining this head
position (looking downward) and
remains for 4 minutes.
ƒ Patient is then sit patient up slowly.

1701
Riyadh et al. Notes
805
ƒ Maneuvers for treating LC-BPPV:
1. Log Roll / Barbecue Maneuver:
o Effective to treat LC-BPPV.
o Method:
ƒ Patient is lying in lateral recumbent
position with affected ear is down for
1 minute.
ƒ Patient body is turned 90 degree into
supine position for 1 minute.
ƒ Patient body is turned 90 degree into
lateral recumbent position with
affected ear is up for 1 minute.
ƒ Patient body is turned 90 degree into
prone position with face looking down
for 1 minute.
ƒ Patient is then setting in upright
position.

1702
Riyadh et al. Notes
806
x Instructions post repositioning maneuvers:
o Remain upright for 48 hours.
o For at least one week, avoid provoking head
positions that might bring BPPV:
ƒ Use 2 pillows when you sleep.
ƒ Avoid sleeping on the "bad" side.
ƒ Don't turn your head far up or far
down.

x Causes of failure of repositioning maneuvers:

o Maneuver didn't work:
ƒ Should keep treating for 4 attempts.
o Canal conversion (5%):
ƒ From PC-BPPV to ipsilateral LC-BPPV
during Eply maneuver.
ƒ Change of nystagmus from
upbeating/torsional nystagmus into
horizontal nystagmus.
ƒ Treated by log roll / barbecue
maneuver.
o Another problem in addition to BPPV:
ƒ Should change treatment.

o Home Exercises:
ƒ Used to treat PC-BPPV at home when the affected side is
not clear.
ƒ Brandt-Daroff Exercises:
x Succeed in 95% of cases.
x Performed in 3 sets/day for 2 weeks.
x In each set, maneuver is performed for 5
times.
x In most persons, complete relief from symptoms is
obtained after 30 sets, or about 10 days.
x Method (1 set):
o Start sitting upright.
o Then move into the side-lying position with
the head angled upward about halfway for
30 seconds, or until the dizziness subsides.
o Then go back to the sitting position and stay
for 30 seconds.
o Then go to the opposite side and follow the
same routine.

1703
Riyadh et al. Notes
807

o Surgical treatment of BPPV:

ƒ Rarely indicated for retractable disabling disease.
ƒ Options:
x Posterior SCC Occlusion:
o Blocks the canal lumen to prevent movement
of endolymph so it becomes unresponsive to
angular acceleration.
o Performed through transmastoid approach.
x Singular Neurectomy:
o Transection of the inferior vestibular nerve
(singular) supplying posterior SCC.
o Performed by accessing the singular nerve
deep to the round window niche via a
transcanal approach.
o Technically difficult.
o Risk of hearing loss (40%).

1704
Riyadh et al. Notes
808
Ménière’s Disease (Idiopathic Endolymphatic hydrops):

- Idiopathic disorder of inner ear where the endolymphatic system is

distended with endolymph.
- Incidence of about 1 in 500.
- Peak age of onset is in the 40-50s.
- Bilateral in 20% of patients and occurs years after the unilateral
symptoms.

- Symptomatic Triad:
1. Episodic Vertigo
2. Tinnitus
3. Fluctuating SNHL
4. Aural fullness (+/-).

- Classic Ménière’s disease:

o Presents with ALL of the above symptoms.

- Variants of Ménière’s disease:

o Presents with any combination of the above symptoms
o Types:
1. Cochlear Hydrops (25%):
x Isolated cochlear variant.
x After several years, vertigo may occur due to block
at the level of ductus reuniens.
x Characterized by:
o Hearing loss
o Tinnitus
o NO vertigo.

2. Vestibular Hydrops (20%):

x Isolated vestibular variant.
x Characterized by:
o Episodic vertigo.
o NO tinnitus.
o NO hearing loss.

3. Lermoyez Syndrome:
x Endolymphatic hydrops and membrane ruptures
isolated to the basal turns of cochlea and the
saccule.
x Symptoms of Meniere's disease are seen in reverse
order.
o Progressive SNHL
o Tinnitus
o Vertigo (at which the hearing loss and
tinnitus resolves).

1705
Riyadh et al. Notes
809
4. Otolithic Crisis of Tumarkin (Drop Attack):
x Acute utriculo-saccular dysfunction.
x Reported in 5% of patients with Ménière’s disease.
x Sudden drop attack due to loss of extensor function
followed by complete recovery.
x Characterized by:
o Sudden unexplained falls.
o NO loss of consciousness.
o NO vertigo
o NO fluctuations in hearing loss.

5. Delayed Endolymphatic Hydrops:

x Loss of hearing later followed by typical Ménière’s
symptoms.

- Pathophysiology of Ménière’s disease (Controversial):

o Normally, endolymph is secreted by stria vascularis, fills the
membranous labyrinth and is absorbed through the
endolymphatic sac.
o Main pathology in Ménière’s disease is distension of
endolymphatic system (endolymphatic hydrops) as a result of
either excessively synthesized or inadequately resorbed
endolymphatic fluid.
o Mainly affecting the cochlear duct (scala media) and the saccule
leading to:
ƒ Dilatation of cochlear duct and bulging of Reissner's
membrane.
ƒ Distention of saccule which may come to lie against the
stapes footplate.
o Membranous labyrinth distention may cause micro-tears
(rupture) which mixes endolymph and perilymph resulting in
some permanent damage to hair cells and instant vertigo.
o The tears then spontaneously seal
o After 2–3 hours the inner ear fluid re-equilibrates with resolution
of the vertigo.
o Repeated ruptures may cause progression of the SNHL

1706
Riyadh et al. Notes
810
- Etiology:
o Idiopathic endolymphatic hydrops (Ménière’s Disease):
ƒ Idiopathic with no known cause.
o Secondary endolymphatic hydrops (Ménière’s Syndrome):
ƒ Endolymphatic hydrops secondary to a suggested cause:
x Allergy:
o 50% of patients with Meniere's disease have
concomitant inhalant and/or food allergy.
o Inner ear acts as the "shock organ"
producing excess of endolymph.
o Respond to allergic desensitization.
x Autoimmune (Familial):
o 10-20% of cases.
o Autosomal-dominant inheritance.
o Associated strongly with:
ƒ Migraine
ƒ Gluten sensitivity
x Hypothyroidism:
o 3% of cases of Meniere's disease are due to
hypothyroidism.
o May benefit from replacement therapy.
x Vascular/ischemic insult:
o Sympathetic over-activity resulting in spasm
of internal auditory artery branches.
o Interfering with the function of cochlear or
vestibular sensory neuroepithelium.
x Viral infection
x Trauma
x Excessive sodium and water retention

1707
Riyadh et al. Notes
811
- Clinical presentation:
o Episodic attacks lasting for minutes to hours with periods of
spontaneous remission lasting for weeks, months or years.
o Consist of:
ƒ Vertigo (96%):
x Onset is sudden.
x Feeling of rotation of himself or his environment.
x Exacerbated with any head movement.
x Accompanied by nausea and vomiting with ataxia
and nystagmus.
x Severe attacks may be accompanied by other
symptoms of vagal disturbances such as abdominal
cramps, diarrhea, cold sweats, pallor and
bradycardia.
ƒ Tinnitus (91%):
x Ipsilateral to the side of the hearing loss.
x Low-pitched non-pulsatile (whistling or roaring).
x Continuous or intermittent.
x Sometimes precede the attack and may persist
during periods of remission.
x Change in intensity and pitch of tinnitus may be
the warning symptom of attack.
ƒ Hearing loss (88%):
x Ipsilateral to the side of tinnitus.
x Fluctuating and progressive in nature.
x Hearing improves after the attack and may be
normal during the periods of remission.
x With recurrent attacks, recovery between episodes
may be incomplete resulting in a progressive SNHL
initially at lower frequencies.
x Over time, hearing loss flattens and involve higher
frequencies.
x 1-2% of patients progress to profound deafness.
x Additional features:
o Recruitment (56%):
ƒ Intolerance to loud sounds.
ƒ Poor candidates for hearing aids.
o Diplacusis (44%):
ƒ Difference in the perception of pitch
between the ears.
ƒ Aural fullness:
x Fluctuates.
x Accompany or precede an attack of vertigo.

1708
Riyadh et al. Notes
812
- Physical examination:
o Otoscopy:
ƒ No abnormality is seen in the tympanic membrane.
o Hennebert sign:
ƒ False positive fistula test.
x Pressure induced vertigo and nystagmus in
absence of labyrinthine fistula.
x Formation of fibrous bands between stapes
footplate and utricle.
ƒ Present in:
x 25% of patients with Meneire’s disease.
x Congenital syphilis.
o Tuning fork test:
ƒ Indicate SNHL.
ƒ Rinne test is positive.
ƒ Weber is lateralized to the better ear.
o Nystagmus:
ƒ Horizontal nystagmus.
ƒ Seen only during acute attack.
ƒ Quick component of nystagmus is towards unaffected
ear (paralytic).
o Head-Thrust Test:
ƒ Assesses integrity of angular vestibuloocular reflex
(AVOR).
ƒ Normal subjects are able to maintain visual fixation on
a target during rapid head movement.
ƒ Asymmetry is only present in 30% of patients with
Meniere disease.

1709
Riyadh et al. Notes
813
- Investigation:
o PTA:
ƒ In early stages, lower frequency SNHL and the curve is
of rising type.

As the disease progresses, middle and higher
frequencies get involved and audiogram becomes flat
type then falling type.

o Speech Audiometry:
ƒ Discrimination score 55-85% between the attacks.
ƒ Discrimination ability is impaired during and
immediately following an attack.

o Special audiometry tests:

ƒ Indicate the cochlear nature of disease.
x Recruitment test:
o Positive.
x SISI (short increment sensitivity index):
o SISI score is better than 70% in two-
thirds of the patients
o SISI score in normal hearing is 15%.
x Tone decay test:
o Decay of less than 25 dB.

1710
Riyadh et al. Notes
814

o Cervical Vestibular Evoked Myopotentials (cVEMP):

ƒ Reflect otolith function.
ƒ Standard test in the workup of a patient with
Meniere's disease.
x Measure the disease severity
x Able to detect bilateral disease.
ƒ Saccule is second most common site affected by
hydrops.
ƒ cVEMP is generated by playing loud clicks in the ear
which moves stapes footplate and stimulates the
saccule.
ƒ This stimulation passes through inferior vestibular
nerve and vestibular nuclei and sends inhibitory
impulses that relax the sternocleidomastoid muscle.
ƒ Patients with Meniere's disease will have increase
threshold or absent response to sounds.

1711
Riyadh et al. Notes
815
o Electrocochleography (ECoG):
ƒ Distension of basilar membrane into scala tympani
(hydrops) causes increase in the normal asymmetry of
basilar membrane vibration.
ƒ Summating potential (SP) in Meniere patients is larger
and more negative.
ƒ SP/AP Ratio:
x Most commonly used value.
x Ratio of SP amplitude and CN-8th action
potential (AP).
x Sensitivity of 50-70%.
x Normally:
o SP/AP ratio is 20-30%.
x In Meniere's disease:
o SP/AP ratio is greater than 50%.

o Videonystagmography (VNG):
ƒ Reveal unilateral weakness on affected side.
ƒ Caloric testing:
x Caloric asymmetry of ≥20% is indicative of
unilateral peripheral vestibular hypofunction.
x Caloric testing is showing reduced response on
the affected side in 75% of cases.

1712
Riyadh et al. Notes
816
o Dehydration test:
ƒ Administration of dehydrating agents (urea, glycerol,
and furosemide) to reduce the increased endolymph
volume in the inner ear and produce a measurable
change in response.
ƒ 60% sensitivity in cases of known Meniere disease.
ƒ Improvement is measured by:
x Audiometrics
x ECoG (reduction in SP negativity)
x Change in the gain of vestibulooccular response
to rotational stimulation.

- Diagnosis:
o Based on clinical history, physical examination, and
Audiological findings, with exclusion of other causes of
hearing loss and vertigo is adequate for diagnosis and
initiating empirical therapy.

- AAOHNS classification of the diagnosis of Meniere's disease:

- Certain:
o Definite Meniere's disease confirmed by histopathology.
- Definite:
1. Two or more definitive spontaneous episodes of vertigo lasting
20 minutes or longer.
2. Audiometrically documented hearing loss on at least one
occasion.
3. Tinnitus or aural fullness in the affected ear.
4. All other causes excluded.
- Probable:
1. One definitive episode of vertigo.
2. Audiometrically documented hearing loss on at least one
occasion.
3. Tinnitus or aural fullness in the treated ear.
4. Other causes excluded.
- Possible:
1. Episodic vertigo of Meniere's type without documented hearing
loss or
2. Sensorineural hearing loss, fluctuating or fixed, with
disequilibrium but without definitive episodes.
3. Other causes excluded.

1713
Riyadh et al. Notes
817

1714
Riyadh et al. Notes
818

1715
Riyadh et al. Notes
819
- Staging of Meniere's Disease:
- Done in certain and definite cases of Meniere's disease.
- Based on average of the pure tone thresholds at 0.5, 1, 2, 3 kHz
(rounded to nearest whole) of the worst audiogram during interval of 6
months before treatment.

- Management:
o All proven therapy is directed at relieving vertigo which is the
most distressing symptom.
o 80% of patients can be effectively managed by medical therapy
alone.
o Acute management:
ƒ Reassurance:
x Patient's anxiety can be relieved by reassurance
and by explaining the true nature of disease.
ƒ Bed rest:
x Head supported on pillows to prevent excessive
movements.
ƒ Precautions:
x Avoid activities requiring good body balance during
the attacks.
ƒ Vestibular sedatives:
x Relieve vertigo.
x Administered intramuscularly or intravenously if
vomiting prevent oral administration.
x Drugs useful in acute attack:
o Dimenhydrinate (Dramamine).
o Prochlorperazine (Stemetil).
o Promethazine theoclate (Avomine)
o Diazepam (Valium).
ƒ Vasodilators:
x Improves labyrinthine circulation.
x Betahistine (Betaserc).
ƒ Corticosteroids:
x May be considered for acute exacerbations.

1716
Riyadh et al. Notes
820
o Chronic Management:
ƒ Precautions:
x As the attack of Meniere's disease is abrupt,
sometimes with no warning symptom, professions
such as flying, under-water diving or working at
great heights should be avoided.
ƒ Behavioral:
x Salt Restriction:
o First-line therapy.
o Reduce endolymph volume by fluid removal.
o Avoid fluid shifts by restricting salt
(<1.5g/day).
o Lack of hard evidence of its efficacy.
x Stress Reduction:
o Symptoms are exacerbated by stress.
o Mental relaxation exercises and yoga helpful
to decrease stress.
x Cessation of smoking:
o Nicotine causes vasospasm.
o Smoking should be completely stopped.
x Elimination of allergen:
o Sometimes, a food or inhalant allergen is
responsible for such attacks.
ƒ Medical:
x Diuretics:
o First-line therapy.
o Reduce endolymph volume by reduce the
production.
o Encourages constant renal output
o Must avoid dehydration which would
exacerbate symptoms.
o Furosemide or acetazolamide taken on
alternate days helps to control recurrent
attacks.
o Lack of hard evidence of its efficacy.
x Vasodilators:
o Improves labyrinthine circulation.
o Betahistine (Betaserc) is H1-histamine
receptor agonist.
o Reduce frequency and severity of vertigo
episodes.

1717
Riyadh et al. Notes
821
ƒ Surgical:
x Indicated after failure of medical therapy.
x Needed in 10–15% of patients.
x Hearing preservation (Serviceable hearing):

1. Trans-tympanic dexamethasone
injection:
ƒ Non-destructive intervention to
improve hearing and vertigo attacks.
ƒ Allows to avoid ablative therapies.
ƒ Single injection (12 mg/ml) to be
repeated after 6-8 weeks if vertigo
recurs.
ƒ Complete resolution of vertigo in 80%.

2. Trans-tympanic Gentamicin injection

(Chemical labyrinthectomy):
ƒ Gentamicin is mainly vestibulotoxic.
ƒ Destructive intervention to ablate the
vestibular function while preserving
the hearing.
ƒ Has advantage of avoiding morbidity
of surgical labyrinthectomy.
ƒ Used as weekly injections (40mg/ml)
for a total of 4-6 weeks titrated to the
patient’s response.
ƒ 10% risk of profound SNHL.
ƒ Patient should be followed up closely
with hearing tests to detect early HL.
ƒ Superior to dexamethasone for vertigo
control in a RCT.
ƒ Complete resolution of vertigo in 90%.

3. Endolymphatic Sac Surgery:

ƒ Includes:
x Endolymphatic sac
decompression.
x Endolymphatic shunt to the
subarachnoid space or mastoid
cavity.
ƒ Non-destructive surgery to preserves
auditory and vestibular function.
ƒ Low morbidity and less successful
than ablative procedures.
ƒ Efficacy of these procedures remains
controversial.
ƒ Rate of success 60–80%.
ƒ Can be done in bilateral Meniere's.

1718
Riyadh et al. Notes
822
4. Meniett Device Therapy:
ƒ Non-destructive intervention.
ƒ Intermittent positive pressure waves
therapy.
ƒ Delivered from external device in the
EAC through ventilation tube to reach
round window and inner ear fluids.
ƒ Pressure waves pass through the
perilymph and cause reduction in
endolymph pressure by redistributing
it through various communication
channels such as the endolymphatic
sac or the blood vessels.
ƒ Improves symptoms of Meniere's
disease.
ƒ Patient can self-administer the
treatment at home.
ƒ It may require a few months before
complete remission of disease is
obtained.
ƒ Meniett device therapy has been
recommended for patients who have
failed medical treatment and the
surgical options are being considered.

5. Selective Vestibular Nerve Section:

ƒ Approach:
x Retro-sigmoid.
x Middle cranial fossa.
ƒ Destructive surgery.
ƒ Achieve vertigo control in 90% of
patients.
ƒ Risk of hearing worsening in 30% of
patients.

1719
Riyadh et al. Notes
823
x NON Hearing preservation (Non-Serviceable
hearing):

1. Labyrinthectomy:
ƒ Approaches:
x Trans-mastoid.
x Trans-canal.
ƒ Destructive surgery that totally
destroy cochlear and vestibular
function.
ƒ Considered for non-serviceable
hearing (>50–60 dB HL or <50%
word recognition).
ƒ High rate of success (90%).
ƒ Must take into account risk of
development of Ménière’s disease in
the contralateral ear later on.

ƒ Cochlear Implantation is a viable option for hearing

restoration in patients Meniere's disease and SNHL.

ƒ In patient with bilateral Meniere's disease, destructive

surgeries to the vestibular system should be limited to
one ear to avoid development of oscillopsia.

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Vestibular Neuritis:

- Vestibular dysfunction due to infection of vestibular nerve.

- Characterized by:
o Severe vertigo:
ƒ Sudden onset.
ƒ Lasting several hours to days.
ƒ Gradual improvement throughout the course.
ƒ May associate with URTI.
o NO Hearing loss.
o NO neurologic impairment
- Pathophysiology:
o Vestibular nerve degeneration secondary to reactivation of a
latent herpes simplex virus infection in the vestibular ganglia.
ƒ In most cases, responsible virus is never identified.
o Superior vestibular nerve is more commonly involved as it is
longer and pass through a narrower bony canal that makes it
more susceptible to compressive swelling.
o 1/3 of patients will develop PC-BPPV months to years after
resolution due to otolithic debris released from the damaged
utricle.
- Diagnosis:
o Clinical history and physical exam.
o Vestibular lab:
ƒ Unilateral decreased caloric response on VNG.
o No associated HL on audiogram
- Management:
o Steroids:
ƒ Mainstay of treatment.
ƒ Improve caloric function.
ƒ Recommended to be started within 3 days of onset of
symptoms.
o Supportive:
ƒ Anti-vertiginous:
x For first 72 hours.
x Long-term anti-verginous medications should be
avoided as it tend to decrease vestibular
habituation.
ƒ Anti-emetics.
o Vestibular rehabilitation.
ƒ Should be initiated as early as possible to promote
central compensation.
ƒ Full recovery may requires weeks to months.

The direction of horizontal or horizontal-rotary nystagmus is towards uninvolved side.

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825
Labyrinthitis:

- Vestibular and auditory dysfunction due to infection of labyrinth.

- Pathophysiology:
o Spread of infection from middle ear into inner ear through:
ƒ Round window
ƒ Annular ligament
ƒ Pre-existing labyrinthine fistula
ƒ Stapedotomy
- Types:
1. Serous labyrinthitis
2. Suppurative labyrinthitis

- Serous Labyrinthitis:
- Diffuse intra-labyrinthine inflammation secondary to viral infection
without pus formation.
- Reversible condition if treated early.

- Clinical features
o Sudden severe vertigo
o Sudden SNHL
o Nystagmus towards affected ear (irritative)

- Management:
o Steroids
o Supportive

- Suppurative Labyrinthitis:
- Diffuse bacterial invasion of the labyrinth with permanent loss of
vestibular and cochlear functions.

- Clinical features
o Sudden severe vertigo
o Sudden SNHL
o Nystagmus away from affected ear (paralytic)
o Meningitis
o Fever

- Management:
o Steroids
o IV antibiotic
o Surgical management of middle ear infection (if
indicated)

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Riyadh et al. Notes
826
Labyrinthine Fistula:

- Defect in the bony capsule of labyrinth.

- Part of membranous labyrinth is exposed and becomes sensitive to
pressure changes.
- Locations:
o Otic capsule
o Oval window
o Round window
- Causes:
o Cholesteatoma:
ƒ Most common locations:
x Horizontal SCC (75%)
x Oval window
x Promontory
o Temporal bone fracture
o Stapes surgery
o Barotrauma
o Acoustic trauma
o Mondini malformation

- Clinical features:
o SNHL (70%):
ƒ No specific audiometric pattern.
ƒ SNHL vary from isolated high-frequency loss to low-
frequency or flat one.
o Transient Vertigo (60%):
ƒ Induced by:
x Valsalva maneuver.
x Pressure-induced (Fistula test)
x Noise-induced (Tullio phenomenon).
o Nystagmus:
ƒ Quick component towards the affected ear (irratative).
o CSF otorrhea

- Diagnosis (No definitive tests):

o Fistula test:
ƒ 50% sensitivity to detect labyrinthine fistula.
ƒ Increases air pressure in the ear canal (tragal pressure
or pneumatic otoscopy) stimulates the labyrinth.
ƒ Causes vertigo and nystagmus.

o CT temporal bone:
ƒ 60% sensitivity to detect labyrinthine fistula.
ƒ Signs:
x Otic capsule bony defect
x Presence of pneumolabyrinth.

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827
- Treatment
o Surgical exploration for possible cases:
ƒ Positive exploration:
x Diagnosed intra-op by:
o Presence of bony defect
o Perilymph leak
x Staging:
o Type I: Bony erosion but intact endosteum
o Type IIa: Violated endosteum but intact
perilymphatic space.
o Type IIb: Violated perilymphatic space.
o Type III: Violated membranous labyrinth
x Treated by:
o Patching with tissue graft (bone pate and
fascia) can achieve hearing preservation and
relief of vertigo.
x If caused by cholesteatoma:
o CWD mastoidectomy
o Complete removal of cholesteatoma matrix
over the fistula with patching of bony defect
EXCEPT the following (High risk of SNHL):
ƒ Firmly adherent
ƒ Infection
ƒ Size >2mm
ƒ Tympanium (promontory)
ƒ Only hearing ear
ƒ LA
ƒ Negative exploration:
x Reasons:
o No fistula exists
o Intermittent fistula
o Too small fistula to be detected.

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Riyadh et al. Notes
828
o Medical care:
ƒ Bed rest with head elevation.
ƒ Avoidance of any straining (sneezing with mouth open,
stool softeners) for 5–10 days
ƒ Systemic antibiotic:
x Prevent spread of infection into the labyrinth.
ƒ Systemic steroid:
x Protective effect on hearing.

Superior Canal Dehiscence Syndrome (SCDS/ Minor’s Syndrome):

- Absence of bon over the superior SCC.

- Mean age range at time of diagnosis is 40s.
- Causes:
o Congenital dehiscence
o Increased CSF pressure
o Post-traumatic

- Pathophysiology:
o Creates “Third-window effect” into the inner ear.
o Under normal circumstances sound pressure enters inner ear
through stapes footplate in the oval window and passing around
the cochlea to exit through round window.
o Presence of dehiscence in superior SCC allows abnormal
movement of endolymph during presentation of loud sounds,
tragal compression or Valsalva maneuver.
o Lead to:
ƒ Decreased sensitivity to air conducted sound
ƒ Increased sensitivity to bone conducted sound

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Riyadh et al. Notes
829
- Clinical features:
o Transient Vertigo (97%):
ƒ Induced by:
x Valsalva maneuver.
x Pressure-induced (Fistula test)
x Noise-induced (Tullio phenomenon).
o CHL:
ƒ Not due to middle ear pathology.
ƒ Caused by the third-window effect that causes dissipation
of acoustic energy transmitted through AC mechanisms.
o Nystagmus:
ƒ Quick component Away from affected ear (paralytic).
o Autophony:
ƒ Resulted from increased sensitivity to bone-conducted
sounds, due to the low impedance for bone-conducted
sound to enter the inner ear at the dehiscence.
ƒ Sensation of increased loudness of patient’s own voice
ƒ Hearing eye movements or blinking.
ƒ Hearing footsteps loudly.
ƒ Differentiated from Autophony resulted from Patulous
Eustachian Tube by:
x NOT hearing own breathing sounds.
x Continuous from the time of onset.
x TM not moving during breathing.
o Pulsatile tinnitus:
ƒ Sensation of hearing patient’s own pulse (Autophony).

- Diagnosis:
o Otoscope:
ƒ Normal examination.
ƒ NO movement of TM synchronous with nasal breathing as
seen with patulous eustachian tube.

o Fistula Test:
ƒ Nystagmus with quick component Away from affected ear
(paralytic).

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Riyadh et al. Notes
830
o Tuning fork:
ƒ Weber tuning fork test lateralizes to affected ear.
ƒ Patients may hear a tuning fork placed on the lateral
malleolus of the foot.
o PTA:
ƒ Bone-conduction thresholds can be below 0 dB (supra-
normal BC threshold).
ƒ ABG can exist even when air conduction thresholds are
normal (ALWAYS request for masked BC when suspecting
SCDS).
ƒ A low Frequency CHL (250 to 1,000 Hz).
ƒ Moderate CHL (mimicking otosclerosis).
ƒ Normal discrimination

o Tympanometry:
ƒ Should be normal in SCDS.
ƒ Important to differentiate it from CHL due to otosclerosis
or ossicular fixation, middle ear fluid,

o Stapedial reflex:
ƒ Should be normal in SCDS.
ƒ Important to differentiate it from CHL due to otosclerosis
where reflexes are absent.
ƒ Patients with intact stapedial reflex and an ABG on PTA
should undergo high resolution temporal CT scan before
proceeding with surgical exploration of middle ear.

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Riyadh et al. Notes
831
o CT temporal bone:
ƒ Diagnosis should never be based on CT scan alone due to
false positive results.
ƒ Specificity and positive predictive value are improved
with high resolution thin-cuts CT scan (0.5 mm) on the
following planes:
x Poschl:
o Parallel to superior SCC.
x Stenver’s:
o Perpendicular to superior SCC.

o Cervical Vestibular Evoked Myopotentials (cVEMP):

ƒ The "third mobile window” associated with dehiscence
creates low impedance pathway that increases sensitivity
of vestibular receptors to sound and pressure stimuli.
ƒ Patients with SCDS will have low threshold response to
sounds.

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832
- Treatment
o Observation:
ƒ For patients with mild symptoms.
ƒ Avoidance of the stimuli that evoke these effects.
o Ventilation tubes :
ƒ May be beneficial in patients with pressure-induced
symptoms.
o Surgical Repair:
ƒ Indicated for patients with severe symptoms.
ƒ Types:
x Reinforcement of oval and round window:
o Trans-canal approach.
o Minimally invasive procedure.
o Using fascia to reinforce and dampening of
oval and round window.
o May alleviate symptoms in some patients.
o Risk of recurrent symptoms.
x Resurfacing of the bony defect:
o Middle cranial fossa approach.
o Eliminate the third mobile inner ear window.
o Using bone cement and fascia to resurface
the bony plate of middle fossa.
o Preserve the physiological function of SCC.
o Risk of recurrent symptoms from slippage of
fascia or bone graft out of the place.
o Less effective than plugging.
x Plugging of superior canal:
o Middle cranial fossa approach.
o Eliminate the third mobile inner ear window.
o Using fascia and bone graft to obliterate the
superior SCC.
o More affective and reliable.
o Vestibular function will be lost.
o Risk of SNHL.
x Combined plugging and resurfacing:
o Most effective approach.
o Effective in alleviating vestibular symptoms
and closing the ABG and normalization of
cVEMP.
o Low risk of recurrence.
x Trans-mastoid approach:
o Alternative approach for SCDS, provided that
the skull base / tegmen is not too low and
that no evidence for large skull base defects
or brain sagging into the ear.

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833

1730
Riyadh et al. Notes
834
Trauma:
- Trauma can cause peripheral vertigo by:
o Labyrinthine concussion
o Temporal bone fracture
o Penetrating trauma
o Blast trauma
o Barotrauma

- Labyrinthine Concussion:
- Post-traumatic disorders of inner ear function.
- NO violation of otic capsule or intra-labyrinthine membranes.
- Short lived symptoms that gradually subside over days to weeks.
- May result in residual BPPV-like symptoms.
- Clinical features:
o Self-limiting acute vertigo.
o Imbalance.
o Nystagmus to affected side.
o Recoverable SNHL “ high frequency SNHL”
o Tinnitus.
o Normal otoscopic findings
o Normal radiologic findings
- Management:
o Reassurance.
o Observation
o Mild sedatives

- Blast trauma:
- Explosive blasts can produce pressure waves > 200 dB sound-pressure
level which cause injury to the inner ear.
- Includes:
o Open-handed slap to the ear
o Explosions.
- Lead to:
o TM Perforation
o Ossicular disruption
o Inner ear damage
- SNHL loss is common and commonly recovers spontaneously.
- Dizziness present in 15% of patients, and it is thought that the otoliths
may be especially vulnerable.

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835
- Barotrauma:
- Inner ear damage secondary to pressure changes.
- Common injury in divers.
- Types:
o Alternobaric trauma:
ƒ Produced by elevated or asymmetric middle ear pressure.
ƒ Seen in:
x Divers while in ascent to the surface.
x Fliers during ascent of the aircraft.
ƒ Secondary to ET dysfunction.
ƒ URTI is a predisposing factor (affect ET patency)
ƒ Symptoms (self-limiting for 10-15 minutes):
x Hearing loss
x Tinnitus
x Vertigo
ƒ Prevented by:
x Frequent equilibration of ME pressure.
x Use of topical decongestants.
x Avoidance of diving or flying during URTI.

o Atmospheric barotrauma:
ƒ Produced by either:
x Extremes of pressure
x Abrupt change in air pressure.
ƒ Symptoms (hours to days):
x Hearing loss (HF-SNHL)
x Tinnitus
x Vertigo (35%)
ƒ Treatment:
x Conservative with bed rest, head elevation and
close monitoring of symptoms.
x Symptoms spontaneously resolve in hours to days.

o Inner ear decompression sickness (IEDS):

ƒ Produced by bubble formation within labyrinth or its blood
supply as consequence of “oxyhelium” use for deep-water
diving.
ƒ The most common decompression injury experienced by
individuals diving to depths > 100m.
ƒ Symptoms (Permanent if treatment is delayed):
x Vertigo (Mainly)
x Hearing loss
x Tinnitus
ƒ Treatment:
x Hyperbaric oxygen within 24 hours after the
injury.

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836
Vestibulotoxic Drugs:
- Several drugs cause ototoxicity by damaging hair cells of inner ear.
- Examples:
o Aminoglycoside:
ƒ Mainly streptomycin, gentamicin, kanamycin.
o Cisplatin.
o Antihypertensives
o Labyrinthine sedatives
o Estrogen preparations
o Diuretics
o Antimicrobials (nalidixic acid, metronidazole)
o Antimalarials

Cogan Syndrome:
- Autoimmune process causing hydrops similar to Ménière’s Disease.
- Disease progresses over months
- Clinical features (Triad):
o Interstitial keratitis:
ƒ Blurriness
ƒ Rapidly progresses to blindness)
o Episodic vertigo.
o Bilateral fluctuating SNHL
- Diagnosis:
o Clinical history
o Physical exam
o Elevated ESR and CRP.
o Non-reactive syphilis tests.
- Management:
o High dose oral corticosteroids 1mg/kg daily (usually resolves
hearing and vestibular dysfunction)
o May consider cyclophosphamide and methotrexate.

Vogt-Koyanagi-Harada Syndrome
- Similar to Cogan syndrome (SNHL, vertigo).
- Associated with:
o Granulomatous Uveitis.
o Depigmentation of hair and skin
o Aseptic meningitis
o Loss of eyelashes.

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837
Otosyphilis
- Syphilis is sexually transmitted disease that can disseminated and
affect any organ system.
- Types:
o Congenital:
ƒ 30% will have inner ear involvement.
o Acquired:
ƒ 80% will have inner ear involvement.
- Timing of onset:
o Early syphilis:
ƒ Symptoms occur within 2 years of exposure
ƒ Vestibular symptoms are less frequent.
ƒ Most common otosyphilis manifestation is sudden hearing
loss.
o Late syphilis:
ƒ Symptoms occur after 2 years of exposure.
ƒ Otosyphilis presentation is similar to Meniere disease with
episodes of vertigo combined with progressive hearing
loss and tinnitus that is often unilateral.
ƒ Interstitial keratitis is found in 90% of patients with late-
onset otologic syphilis.
ƒ Hutchinson’s triad in late congenital syphilis:
x Interstitial keratitis
x SNHL
x Notched incisors
- Diagnosis:
o Hennebert's sign
o Lab tests:
ƒ Non-treponemal tests (70% sensitivity for otosyphilis):
x VDRL
x Rapid plasma regain test
ƒ Treponemal tests (95% sensitivity for otosyphilis):
x Fluorescent treponemal antigen absorption test
[FTA-ABS].
x Micro-hemagglutination assay for Treponema
pallidum antibodies [MHA-TP].
- Management:
o Penicillin IM
o Prednisone

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838
Acoustic neuroma:
- Classified in peripheral vestibular disorders as it arises from CN VIII
within internal acoustic meatus.
- Causes only unsteadiness or vague sensation of motion.
- Severe episodic vertigo is usually missing.
- Other tumors of temporal bone (e.g. glomus tumour, carcinoma of
external or middle ear and secondaries), destroy the labyrinth directly
and cause vertigo.

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839
Central Vestibular Disorders:

Vestibular Migraine/ Migraine-Associated Vertigo:

- Migraine is characterized by recurrent headaches associated with:
o Nausea and vomiting
o Hypersensitivity to light, sound and smell.
- Migraine affects 25% of women, 15% of men and 5% of children.
- Typically begins in young adulthood.
- Vertigo is extremely common in patients with migraine (25%).
- Pathophysiology of vestibular migraine remains unclear.
- Patients often report a prior history of migraine headaches that seem
to have resolved.

1736
Riyadh et al. Notes
840

- Clinical picture:
o Vertigo does not usually present as an aura immediately
preceding the headache, as a prodrome.
o Dizziness is described as vertigo (spinning, rocking, swaying) or
simply disequilibrium.
o Variable in duration:
ƒ Lasting minutes to days in episodic cases, or constant
disequilibrium lasting months.
o When to suspect Migraine-Associated Vertigo:
ƒ Dizziness associated with photophobia, menstrual
association, and nasal stuffiness at time of the attack.
ƒ No history of hearing fluctuation or positional component.
ƒ Spells of vertigo or disequilibrium last more than a day.
ƒ Positive family history of migraines.

- Treatment:
o Dietary and lifestyle modifications:
ƒ Regular sleep and exercise.
ƒ Avoid trigger factors:
x Stress
x Weather changes
x Food:
o Red wine, aged cheese, yogurt, caffeine and
chocolate.

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Riyadh et al. Notes
841
o Medical management:
ƒ Prophylactic medications:
x Goal is to reduce symptom frequency and severity
by 50-70%.
x Benefits are seen after 6-8 weeks of therapy.
o Beta blockers:
ƒ Propranolol
o Calcium channel blockers:
ƒ Nifedipine or Verapamil
o Antidepressants:
ƒ Nortriptyline or venlafaxine
o Anticonvulsants:
ƒ Sodium valproate or gabapentin
ƒ Abortive medications:
o Should not be used > 6-8 times per month
due to their known rebound effects
ƒ Sumatriptan

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842
Vertebrobasilar insufficiency (VBI):
- Common cause of central vertigo in patients over age of 50 years.
- Pathophysiology:
o Transient decrease in cerebral blood flow due to Atherosclerosis.
o Compression of vertebral artery compromises flow to the
posterior (PICA) and Anterior Inferior cerebellar Arteries (AICA).
- Precipitated by:
o Hypotension
o Neck Hyperextension or excessive rotation.
- Clinical picture:
o Abrupt onset of (lasting for minutes):
ƒ Vertigo
ƒ Nausea and vomiting
ƒ Headache
ƒ Diplopia
ƒ Ataxia
ƒ Numbness
ƒ Weakness
ƒ Dysphagia
- Subclavian Steal Syndrome:
o Occlusion or stenosis of the subclavian artery proximal to the
vertebral artery.
o Results in reverse flow of the vertebral artery in favor of the
ipsilateral arm.
o Symptoms are precipitated by exercise of upper extremities.
- Diagnosis:
o Clinical history and physical exam
o Radiography (CT and MRI brain).
- Management:
o Anticoagulation (antiplatelet medication)

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Riyadh et al. Notes
843

Lateral Medullary Syndrome (Wallenberg's syndrome):

- Posterior Inferior Cerebellar Artery (PICA) Syndrome.
- Pathophysiology:
o Embolic event or thrombosis of ipsilateral vertebral or Posterior
inferior cerebellar artery (PICA).
o Results in an infarction of lateral medullary region of brain stem
(serving CN V-X, Cerebellum, and sympathetic ganglion), spares
cochlear nucleus.
- Clinical features:
1. Ipsilateral loss of facial sensation: (CN-V)
2. Ipsilateral loss of lateral rectus: (CN-VI)
3. Ipsilateral loss of facial musculature: (CN-VII)
4. Acute vertigo and nystagmus: (Vestibular CN-VIII).
5. Ipsilateral palatal paresis (dysphagia): (Pharyngeal plexus,
Nucleus Ambiguus, CN-IX, CN-X).
6. Ipsilateral vocal fold paralysis (Dysphonia): (Pharyngeal
plexus, Nucleus Ambiguus, CN-IX, CN-X).
7. Ataxia: Incoordination of ipsilateral limbs (falls toward lesion).
8. Ipsilateral horner syndrome: (Anhydrosis, Ptosis, Miosis)
from damage to Preganglionic sympathetic fibers.
9. Contralateral loss of pain and temperature: Injury to the
crossed spino-thalamic fibers
- Diagnosis:
• Cerebral Angiogram, CT Brain (wedge-shaped infarct)
- Management:
• As per cerebrovascular accident protocols.

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Riyadh et al. Notes
844
Cerebellar disease:
- Affected by:
o Hemorrhage (hypertension)
o Infarction (occlusion of arterial supply)
o Infection (otogenic cerebellar abscess)
o Tumours (glioma, teratoma or haemangioma).
- Clinical features:
o Severe vertigo
o Vomiting
o Ataxia simulating an acute peripheral labyrinthine disorder.
o Incoordination
o Past-pointing
o Adiadokokinesia
o Rebound phenomenon
o Wide-based gait.

Multiple sclerosis
- Demyelinating disease of CNS.
- Affecting young adults.
- Result in “plaques” within the central vestibular system.
- Clinical features:
o Vertigo and dizziness:
o Blurring or loss of vision
o Diplopia
o Dysarthria
o Paraesthesia
o Ataxia.
o Spontaneous nystagmus may be seen.
o Acquired pendular nystagmus, dissociated nystagmus and
vertical upbeat nystagmus are important features in diagnosis.

Tumors of brainstem and floor of IVth ventricle:

- Gliomas, astrocytomas may arise from pons and midbrain.
- Medulloblastoma, epidymomas, epidermoid cysts or teratomas may
arise from floor of IVth ventricle.
- Cause vertigo and dizziness and other neurological signs and
symptoms.
- CT scan and magnetic resonance imaging are useful in diagnosis.

Epilepsy
- Vertigo may occur as an aura in temporal lobe epilepsy.
- History of seizure and/or unconsciousness following the aura may help
in the diagnosis.
- E.E.G. may show abnormalities during the attack.

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845

Multiple Sclerosis
 Multifocal demyelinating disease of CNS; presents 3rd/4th decades
 Plaques develop, disrupt transduction and cause acute symptoms
 Remissions associated with remyelinization and symptom resolution
 Common presenting symptoms: blurred vision (optic neuritis); diplopia;
weakness; sensory disturbance; clumsiness; ataxia
 Internuclear ophthalmoplegia, disorder of conjugate lateral gaze in which
the affected eye shows impairment of adduction
 Vestibular symptoms: variable; episodic vertigo to imbalance; up to 50% of
MS patients get vestibular symptoms at some point
 MRI shows plaques but may be normal during remission
 CSF shows elevated IgG
 Tx: treat symptoms; high-dose steroids; experimental stuff

Tumours
 CP angle lesions (AN, meningioma)
 Episodic vertigo, positional vertigo and disequilibrium when small
 As it grows, function declines and symptoms improve (compensation)
 Disequilibrium can return if gets big enough to compress cerebellum
 Brun nystagmus: fine, horizontal, lateral on contra gaze AND coarse,
horizontal, lateral on ipsi gaze; can happen with big lesions (fine nystagmus
due to dysfunction of vestibular nerve and inner ear while coarse nystagmus
due to cerebellar dysfunction)
o Gaze evoked nystagmus that is pathologic may be seen ipsilateral to a
lesion of the brain stem or cerebellum and contralateral to a peripheral
vestibular pathway lesion
o Brun nystagmus is an ipsilateral gaze paretic and contralateral high
frequency, low amplitude nystagmus

Miscellaneous Central Vestibular Disorders

 Vascular loop compression of CN VIII: controversial; many have one without
symptoms; not likely to do anything about it currently because we don’t have
a firm diagnostic modality and the treatment involves a craniotomy and
decompression
 Seizure disorder: very small percentage of epileptics get vertigo with
episodes; treatment with anti-seizure drugs can help

Otology
5
Riyadh et al. Notes
846
Cervical Vertigo:
- Dizziness caused by disorders of neck and cervical spine is poorly
understood and relatively uncommon.
- It is known that neck afferents have a role in the coordination of eye,
head, and body spatial orientation.
- Perception of head rotation can be driven by vestibular, proprioceptive,
or visual inputs.
- Cervical vertigo must be by definition proprioceptive in nature.
- Unilateral local anesthesia of cervical roots can cause ataxia without
nystagmus in humans.
- Patients with chronic cervicobrachial neck pain have worse results on
posturography tests.
- In clinical practice, it is necessary to exclude neurologic, vestibular,
and psychosomatic disorders before a disorder of the craniovertebral
junction can be given serious consideration.

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847

Approach to Tinnitus:

- Tinnitus:
- Ringing sound or noise in the ear.
- Origin of this sound is within the patient.
- Usually unilateral but may also affect both ears.
- Vary in pitch and loudness.
- Described by the patient as roaring, hissing, swishing, rustling or
clicking type of noise.
- Most prevalent from 40-70 yrs.
- Men > Women.

1. Subjective Tinnitus:
- Perception of sound in the absence of any stimulation (Acoustic,
Electrical, or External stimulation).
- Not audible to another person.
- Most common type.
- Typically associated with a high frequency HL (3000–5000 Hz)
- Pitch of tinnitus may correlate with the frequency of hearing loss.
- Pathophysiology is largely unknown.
- 25% improve spontaneously.

- Otologic Causes:
o Presbycusis: very common (75%)
o NISNHL: High freq SNHL most consistent factor with tinnitus
o Meniere’s: Almost all have tinnitus
o Prolonged otitis
o Recurrent labyrinthitis.
o Otosclerosis

- Drugs:
o ASA: Most common drug.
o Mercury, Arsenic and Lead.
o Caffeine.

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848

1744
Riyadh et al. Notes
849
2. Objective Tinnitus:
- Perception of sound caused by an internal body sound or vibration.
- Audible to another person.
- Pulsating in character (Asking the patient to perform light physical
activity may confirm the pulsatile nature).
- Exacerbated with a CHL.

- Vascular Causes:
o Soft, rushing, pulsatile sound.
o Synchronous with heartbeat.
o Increase with exercise
o < 10% of tinnitus.
o Small percentage have bruit
o Benign Intracranial Hypertension Syndrome, Atherosclerotic
carotid artery disease and Glomus tumors compose two thirds of
definable causes.

1. Pseudotumor Cerbri (Benign Intracranial Hypertension

Syndrome):
ƒ Most common cause of pulsatile tinnitus.
ƒ Overweight females, 20–30 years old
ƒ Increased ICP without focal neurological signs.
ƒ Caused by systolic pulsations of CSF transmitted to dural
venous sinuses.
ƒ Diagnosed by MRI and LP to measure CSF pressure.
ƒ May be associated with a mild SNHL.
ƒ Rx: weight loss and diuretics.

2. Vascular Tumors:
ƒ Most common is Glomus Tympanicum or Jugulare.
ƒ Reddish/blue mass behind TM.
ƒ Decreased hearing.
ƒ Diagnosed with CT with contrast to look for erosion of
carotico-jugular spine or lesion in ME space.

3. Venous Hum:
ƒ Soft and low-pitched.
ƒ Caused by turbulent blood flow through the jugular bulb
or transverse sinus.
ƒ Found commonly in patients with:
x High jugular bulb.
x HTN
ƒ Tinnitus typically disappears in:
x Upright position:
x Pressure over ipsilateral IJV.

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4. Arterial Bruits:
ƒ Whooshing sound synchronous with heartbeat.
ƒ Transmitted sounds.
ƒ Caused by:
1. Apparent course of ICA in the middle ear.
2. Atherosclerotic carotid artery disease.
3. Vascular loops in internal auditory meatus pressing
on CN-VIII.
ƒ Diagnosed by CTA, MRA or Duplex U/S of carotids.

5. Arteriovenous malformations:
ƒ Intracranial or Preauricular.
ƒ Connections between Occipital artery and Transverse
sinus, ICA and vertebral vessels, or middle meningeal
artery and GSPA.
ƒ Diagnosed by MRA.
ƒ Rarely need Tx.

- Mechanical Causes:

1. Patulous Eustachian Tube:

ƒ Abnormally patent Eustachian tube.
ƒ Ocean roar in ear synchronous with Nasal Respiration.
ƒ Absent on lying flat.
ƒ Autophony (Hyperacusis to one's own speech and bodily
sounds).
ƒ Hypermobile TM moves with respiration.
ƒ Causes:
x Post-radiation patients
x After significant weight loss
x Stroke.
x Injury to CN-V
x Iatrogenic injury to Tensor veli palatini in Cleft
palate surgery.
ƒ Rx: Mucosal irritants, Eustachian diathermy probe (often
requires a pressure equalization tube), may consider
Teflon paste injection into the Torus tubaris (less
effective).

2. Palatal Myoclonus:
ƒ Rapid clicking sound caused by the contraction of Palatal
muscles and ET.
ƒ May be evaluated by Nasopharyngoscopy in an awake
patient.
ƒ Treat with Botox injections, Antiepileptics or muscle
relaxants (Clonazepam, Diazepam).

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3. Tensor Tympani/ Stapedius Syndrome:
ƒ Spasm or myoclonus of Tensor tympani or stapedius
muscle.
ƒ Fluttering, low frequency tinnitus.
ƒ Accentuated by External sound.
ƒ Dx: Tinnitus synchronous with TM movement.
ƒ Rx: Avoidance of Stimulants, Reassurance, rarely requires
section of the tensor tympani muscle.

4. Spontaneous Otoacoustic Emissions:

ƒ Rare cause of objective tinnitus

- Evaluation of pulsatile tinnitus:

o Retro-tympanic mass on otoscope:
ƒ Request contrast CT to evaluate for :
x Glomus tumors
x Aberrant carotid artery
x Jugular bulb abnormalities

o No Retro-tympanic mass on otoscope:

ƒ If tinnitus improves with upright positon or ipsilateral IJV
pressure:
x Venous hum.
x Doesn’t require further evaluation.

ƒ If tinnitus doesn’t improve with upright positon or

ipsilateral IJV pressure:
x Request MRI/MRA to evaluate for:
o BIH.
o Vascular loops.
o AV malformations.
x Request Carotid Duplex US to evaluate for:
o Atherosclerotic carotid artery disease
o Carotid duplex ultrasonography.

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Approach to Tinnitus:
- Similar approach to Hearing loss with special attention to:
o Character of Tinnitus:
ƒ Pulsatile or Non-pulsatile.
ƒ Unilateral or Bilateral.
ƒ High-pitched (Ringing, Hissing) or Low-pitched (Roaring,
Buzzing).
ƒ Progression and Frequency
ƒ Level of discomfort (Difficulty with sleeping)
o Complete H&N examination including stethoscope to auscultate
for objective tinnitus.
- Work-up:
o Audiology evaluation:
ƒ Diagnostic testing should include PTA, speech
discrimination testing, and tympanometry.
ƒ Indications:
x Recommended indications:
1. Unilateral tinnitus.
2. Associated with hearing difficulties.
3. Persistent tinnitus (≥ 6 months).
x Optional indications:
o Any tinnitus.
o Imagining:
ƒ Indications:
1. Unilateral tinnitus:
o MRI with contrast to rule out VS.
2. Asymmetric hearing loss:
o MRI with contrast to rule out VS.
3. Pulsatile tinnitus:
o CT/CTA to evaluate vascular abnormalities
(Glomus, apparent carotid in ME).
o MRI/MRA to evaluate AVM or vascular loops.
4. Focal neurological abnormalities:
o MRI/CT brain.

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Management:
1. Treat Reversible causes:
o Medications Review (ASA/NSAIDs)
2. Behavioral:
o Lifestyle modifications:
ƒ Smoking cessation
ƒ Avoidance of caffeine, chocolate, tea
ƒ Avoid loud noise
o Home-masking techniques:
ƒ White Noise at night.
ƒ Placing Radio between stations.
o Cognitive behavioural therapy (CPT):
ƒ Counseling/psychological therapy.
ƒ Biofeedback for stress reduction
ƒ Habituation:
3. Medical:
o Strong recommendations against its routine use.
o No medications approved by FDA for treatment of tinnitus.
o No medications or dietary supplements showed improvement in
tinnitus perception.
o Examples:
ƒ Intra-tympanic steroid injections.
ƒ Antidepressants (Tricyclic antidepressants, SSRI).
ƒ Anxiolytics (Benzodiazepines).
ƒ Ginkgo Biloba
ƒ Melatonin
ƒ Zinc
4. Hearing Aids:
o Indicated for subjective tinnitus with HL.
o Reduces Tinnitus by amplifying ambient sound to mask Tinnitus.
o Simplest method of "Direct Masking".
o 25% improvement with severe tinnitus.
5. Masking Devices:wide-band sound (known as tinnitus maskers, white noise generators or wide-band sound generators)
o Masking devices utilize a band of White Noise centered around
the Tinnitus Frequency (Pitch matched).
o May be combined with Hearing Aids.
o Indicated for patients with persistent, bothersome tinnitus.
6. Habituation:
o Tinnitus retraining therapy.
o Stimulation with Broad-band noise up to 16 hours/day.
o Level is increased until it is audible but not mask the tinnitus
o Over months, Patients symptom improves
7. Surgery:
o Correct otologic conditions (Otosclerosis).
o CI
good outcomes for min mask level (MML) of 2- or 3- dB SL, not good for 10- to 15dB SL (masking
limited to normal or near-normal hearing)

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- Hyperacusis:
- Increase sensitivity to sound that wouldn't normally trouble normal
individual.
- Painful at 40-50 dB.
- 25-40% association with tinnitus.
- Different from Recruitment – painful with loud sounds.
- May develop Overprotection (Overzealous earplug use) and
Phonophobia.
- Therapy to wean off earplugs/earmuffs
- Tinnitus Retraining Therapy (TRT)
- High association with Williams Syndrome:
o Rare Neurodevelopmental disorder.
o Caused by a deletion of about 26 genes from Long arm of
chromosome 7.
o Characterized by a distinctive "Elfin" facial appearance, along
with a low nasal bridge.
o Idiopathic infantile hypercalcemia.
o Mental retardation.
o Cardiovascular anomalies:
ƒ Supravalvular aortic stenosis
ƒ Peripheral pulmonary artery stenosis

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