MANAGEMENT OF
COMPLICATIONS OF
STRABISMUS
SURGERY
Presenter : Dr Abhishek G
Guide : Dr Prajna Ghosh
COMPLICATIONS OF STRABISMUS SURGERY
SURGICAL SITE RELATED- INTRAOPERATIVE / POST OPERATIVE
ALIGNMENT RELATED
INTRAOPERATIVE
COMPLICATIONS
1. SCLERAL PERFORATION
Recognise the perforation- feeling of passing the needle too deep or
appearance of small piece of uvea or a bead of vitreous on the tip of
suture needle.
IDO to inspect underlying retina after the procedure.
If a large retinal tear is noted or if it a small tear in a patient at a high risk
of RD,laser retinopexy may be required with close follow up for
endophthalmitis or RD.[1]
In a child with well formed vitreous,there is a low risk of RD and laser may
not be necessary.
Apply antibiotic drops and 5% povidone iodine solution on the operative
site.
Subconjunctival antibiotic / prescribe topical or oral antibiotics post
operatively.
Educate the patient regarding warning signs such as flashes/floaters /BOV.
Maintain adequate surgical exposure
Use proper needle passing techniques.
Use of hang back recession allows excellent exposure regardless of
amount of recession performed
Practice caution in at-risk patients such as high myopes with staphyloma.
[2][3]
CASE OF SCLERAL PERFORATION
27 year old with alternating exotropia was planned for LE adjustable R and
R surgery.
LE peri bulbar block was given following which conjunctival ballooning was
noted.
Patient did not c/o any pain or visual disturbances immediately but in the
afternoon of surgery,patient complained of visual disturbances.
Vitreous hemorrhage was found.
Retinal tear not identified due to hemorrhage.
LE scleral perforation was the provisional diagnosis and head end
elevation was advised.
Pre retinal hemorrhage was noted close the the inferior arcade sparing the
macula.
Scleral perforation one
week post operatively.
Scleral perforation one day after surgery
2.LOST MUSCLE
Surgical emergency.
Immediate attempts to recover the lost muscle should be made.
Pulled In Two Syndrome- occurs at the junction between muscle belly and
muscle tendon resulting in loss of posterior muscle belly.[4]
Primary prevention :
Gentle surgical techniques when isolating and securing the muscle belly.
Rotating the globe towards the resected muscle rather than pulling the
tight muscle belly anteriorly
Direct placement of scleral sutures at the site of the new insertion instead
of utilizing a hang-back technique from the original insertion.
Diagnosis:
Weakness of the lost muscle on motility testing.
Large angle incomitant Strabismus.
Specialized tests such as saccadic velocities, force generations and forced ductions can
distinguish here between lost or slipped muscles and excessive scarring or fast
adherence.
Imaging helps to localize lost muscles.
Attempts should be made to retrieve the muscle promptly.
Generally,exposure of the surgical site is better at the time of initial surgery and the
newly exposed tissue planes make identification and retrieval of a lost muscle easier
than if surgical repair is attempted hours or days later.
Avoid purposeless exploration as it can result in hemorrhage / fat intrusion into the
surgical site[4]
If the muscle capsule and inter muscular septum have undergone
extensive dissection,the muscle will retract through Tenon's capsule to
enter the posterior orbit.
We should identify the potential space within the Tenon's capsule through
which the muscle has retracted.
Repair is carried out through a large limbal incision.
Retract the conjunctival flap and tenon's capsule anteriorly to expose the
global surface of the Tenon's capsule which is inspected using a fine
toothed forceps in an attempt to locate the potential space where the
muscle has passed.
Excessive dissection of posterior intermuscular
septum,muscle capsule and check ligaments does
not enhance the effect of recession surgery but
increases the chance that the muscle will retract
into the posterior orbit.
Hence it should be avoided.
Avoid manipulating sutures with sharp instruments
as it can cause weakness of the sutures.
Transposition surgery is considered in case the lost
muscle is not found. (a) A lost rectus muscle will be found along the
adjacent orbital wall. (b) A common mistake is to
search for the muscle along the posterior aspect
of the globe (Coats DK, Olitsky SE, Strabismus
surgery and its complications, Springer 2007)
3.SLIPPED MUSCLE
Risk of a slipped muscle increases when the muscle is tight such as dysthyroid
Orbitopathy or the contacted agonist of a paretic muscle.
Risk reduced by using full thickness bites while passing the muscle suture.
Spl groove hooks or muscle clamps while dealing with tight muscles.
2 locking bites for adequate capture of muscle fibres.
Slipped muscle is differentiated from a lost muscle in which no portion of the
muscle,including its capsule,remains attached to the sclera.
Duction deficit is lesser than in lost muscle.
Once the muscle capsule is located,it is carefully followed posteriorly where the
muscle /tendon itself will be found attached to muscle capsule.The muscle should be
isolated,secured with sutures and brought back in contact with the globe.
Slipped left medial rectus muscle following strabismus surgery showing showing exotropia in
primary position and inability to adduct the left eye. Image credit: BCSC Pediatric
Ophthalmology and Strabismus.
4.OCULOCARDIAC REFLEX
Dx:
Sinus bradycardia
Reduced arterial pressure
Arrhythmia
Asystole
Rarely cardiac arrest
Rx:
Stopping the triggering stimulus will terminate the reflex.
IV anticholinergics -atropine
POST-OPERATIVE
COMPLICATIONS
1.DELLEN
It typically develops within the first 2 weeks of
surgery and occurs more frequently in patients
operated with a limbal approach.
More common in resection procedures and occurs
much more in very large resections.
More common after horizontal muscle surgeries.
Rx- Corneal rehydration
Lubricating eye ointment.
Spontaneous reduction in few days to a week.
Patients with tear film deficiency require a closer
follow up.[1]
2.INADVERTENT ADVANCEMENT OF THE PLICA SEMILUNARIS CONJUNCTIVAE
Results from during of plica to the conjunctiva
adjacent to the limbus.
During limbal surgery the anterior aspect of the limbal
conjunctival flap gets folded beneath the plica.
We need to avoid excessive hydration during surgery
which may lead to greater distortion of the anatomy
by increasing edema of tissues.
Coats DK, Olitsky SE, Strabismus surgery and its complications, S
Sterile methylene blue skin marking pen should be 2007
used to mark the anterior corners of the conjunctival
flap before proceeding with surgery.
These corner marks are easy to locate and they
facilitate accurate conjunctival closure.
3.CHEMOSIS
Rx- lubricating eye ointment
Lid taping if conjunctiva protrudes anterior to the eyelids.
Significant improvement occurs in few days to a week.
4.PYOGENIC GRANULOMA
Fleshy red mass with relatively rapid growth.
Most lesions resolve spontaneously.
Topical steroids - efficacy not proven.
Surgical excision if topical rx fails.
Pyogenic granuloma following left lateral rectus muscle surgery.
Image credit: Espinoza GM, Lueder GT. Conjunctival pyogenic
granulomas after strabismus surgery. Ophthalmology. 2005;
112(7): 1283-1286, via BCSC Pediatric Ophthalmology and
Strabismus.
4.EXTRUDED / EXPOSED TENON'S FASCIA
Ensuring that the edges of the conjunctival incision are well opposed or
sutured prevents this complication.
If a large amount of tenon's fascia is extruding through the conjunctival
incision at the end of the case,we can excise the extruding tenon's fascia
or place additional sutures in the conjunctiva to fully internalize the
exposed fascia.
If found postoperatively,the exposed tenon's fascia is trimmed from the
conjunctival surface.
Topical steroids if excision is not possible-resolution occurs within days to
weeks.
5.EPITHELIAL INCLUSION CYST
When an epithelial inclusion cyst forms at the site of muscle reattachment
to the sclera,failure to recognize that the muscle is attached to the cyst
can result in detachment of the muscle.
Very small cysts- removed by small conjunctival incision placed adjacent
to the cyst.
Medium to large cysts- best removed through standard limbal conjunctival
incision.
Limbal incisions allow the surgeon to maintain control of adjacent muscles
during excision.
Isolation of adjacent muscles on a muscle hook can ensure that accidental
disinsertion of the muscle does not occur if the cyst is large and located
too close to the muscle.
Epithelial inclusion cysts are removed intact.
Manipulating the cyst with forceps should be avoided as
the cyst can rupture.
Once the cyst is adequately exposed,it is carefully excised
from the underlying sclera.
Attachment of the cyst to the sclera is typically very firm.
Care must be taken to transect these fine but firm Coats DK, Olitsky SE, Strabismus surgery and its
attachments to the underlying sclera without rupturing complications, Springer 2007
the cyst.
If ruptured,all the visible elements of the cyst are
removed with irrigation of the operative site to wash away
epithelial cells and application of cautery to the sclera
where the cyst was attached.
Intracyst injection of alcohol
6.ANTERIOR SEGMENT ISCHEMIA
Risk factors include operating on multiple muscles on the same eye,prior
squint or scleral buckling surgery,older patients with DM
/HTN/Vasculopathy/old age.
Prevention:
Reduce the number of muscles being operated on each eye.
Utilizing botulinum toxin.
Vessel sparing surgery.[3]
Fornix incision has slightly reduced effect on anterior segment perfusion.
Diagnosis:
Iritis
Corneal edema
DM folds
Rarely anterior segment necrosis/phthisis bulbi
OCT-A FOR DETECTION OF ANTERIOR SEGMENT ISCHEMIA POST SQUINT SX
ICG-A reveals iris filling defects to assess patient's risk
for ASI.
ICG-A - invasive and time consuming,potential side
effects.
OCT-A images iris vasculature. It revealed a significant
decrease in the mean vessel density of the iris quadrant
adjacent to the operated muscle post-operatively.
It shows iris vessel filling defects comparable to ICG-A.
It gives quantitative vessel density values that can be
compared pre operatively and post operatively.
Management:
Topical and systemic corticosteroids to relieve inflammation
Cycloplegic drugs can be used to prevent synechiae.
Topical 0.9 % NaCl drops can be used to reduce corneal edema.
IOP control
7.STRETCHED SCAR SYNDROME
Overcorrection occurs several months later.
At the time of reoperation, an amorphous scar tissue separating the
muscle tendon from the scleral attachment is generally found.
Scar lengthening after surgery is responsible for the recurrent
deviation.
The scar may be difficult to distinguish from the muscle tendon.
The scar is excised after placing sutures in the muscle tissue MANAGEMENT OF STRETCHED
SCAR– INDUCED SECONDARY
posterior to the scar.
STRABISMUS BY MOHAMED F. FARID,
MOHAMED R. MAHMOUD &
MOHAMED A. AWWAD
The muscle is then reattached to the globe.
Failure to remove the scar completely increases the risk of recurrence
Excision of the scar corrects secondary deviations and improves
limitation of ocular duction.
8.FAT ADHERENCE SYNDROME
Avoid damage to the posterior tenon's capsule especially
during IO surgery.
Direct visualisation of the posterior border of IO muscle
during its isolation can help to reduce the risk of penetrating
the Tenon's capsule.
Avoid blind sweeping of the ITQ.
Small amounts of orbital fat that protrude through a rent in OPHTHALMOLOGY (ROCHESTER, MINN.) 2011
the posterior tenon's capsule can be repositioned into the
extraconal space followed by closure of the rent.
If a large amount of extraconal fat has entered the
episcleral space,a hemostat is placed across the fat at the
opening of the defect and excised.
The defect in tenon's capsule can be then sutured using
absorbable sutures.[7]
9.EYELID RETRACTION AND ADVANCEMENT FOLLOWING VERTICAL MUSCLE SURGERY
Be aware that the external aspect of the sheath of the vertical rectus
muscles is adherent to the internal surface of the eyelids.
Bothersome alteration of the eyelid position occurs following recession 5
mm or more.
Generous dissection around the attachments between the vertical rectus
muscles and the eyelids can be performed at the time of surgery to prevent
post op eyelid changes.
Care should be taken during posterior dissection of the attachments not to
disturb the vortex veins that are usually found adjacent to the medial and
lateral borders of the muscle.
Eyelid retraction or ptosis may require oculoplasty opinion to restore the
normal eyelid configuration, if it prevents proper eyelid closure or affects
peripheral vision.[8]
Lower lid lag after IR
recession
Palpebral fissure changes after vertical muscle surgery
10.POST OPERATIVE INFECTION
Treat any superficial infection or bacterial overgrowth preoperatively and use
sterile meticulous techniques during surgery.
Orbital imaging with MRI/CT - preseptal or orbital cellulitis.
For infections - Gram stains or cultures.
Rx- Topical antibiotics- conjunctivitis
Systemic antibiotics - preseptal or orbital cellulitis
Intravitreal antibiotics - endophthalmitis
Hospitalization for iv antibiotics for serious infection
Subconjunctival or orbital abscess- Drainage
Orbital cellulitis/endophthalmitis carry risk of loss of vision.[6]
11.ALLERGIC REACTION
Due to allergy to materials or medications in the peri operative period.
Topical corticosteroids
Anti histamines
12.CONJUNCTIVAL SCARRING
Risk is minimized by careful wound closure
Rx- surgical excision if scar tissue to smoothen the
conjunctiva.
The risk of conjunctival scarring increases with
each surgery performed.
Conjunctival scarring involving the plica semilunaris following strabismus surgery. Image
courtesy of Scott Olitsky, MD, via BCSC: Pediatric Ophthalmology and Strabismus.
13.CHANGE IN REFRACTION
Occurs post operatively due to change in force the EOM places on the
cornea through its attachment to the sclera.
For decreased vision post operatively,retinoscopy or corneal topography
has to be done to rule out irregular astigmatism.
Optical correction of refractive error.
Change in refraction is typically temporary and resolves after a few
months.
ALIGMENT RELATED
COMPLICATIONS
1.UNSATISFACTORY EYE ALGNMENT
Sometimes,prisms can be incorporated temporarily (Fresnel prisms) or
permanently into glasses.
Prisms can be weaned slowly over time as fusional mechanisms build
allowing normal BSV w/o prisms.
Repeat Squint surgery may be required.
Convergence or divergence exercises post operatively help align the eyes.
Overcorrection 1 week post
operatively which
automatically got corrected
and became orthrotropic by
second week.
Gross under correction
after bilateral LR
recession.Below picture
was the pre operative
photo of the same
patient.
Overcorrection after
routine R and R
procedure followed
by diplopia
2.DIPLOPIA
It can be prevented by careful assessment of the binocular potential prior
to surgery.
Amblyoscope testing can assess a patient's fusional potential.
Adjustable techniques help prevent over correction.
Prisms
Occlusion of one eye with eye patch
Bangerter's filters
Additional surgery.[9]
3.IATROGENIC BROWN SYNDROME
Can occur following SO tightening procedures.
Limitation of elevation of eye in adduction.
Prevention- Avoid over tightening of SO tendon during surgery.
When placing sutures for SO tuck,sutures can be tied in a reversible shoe
string pattern and then FDT is done to assess for limitation of elevation in
adduction.
If there is limitation,then the amount of tuck should be reduced.
Mgt- Observe
SO tucks often relax with time.
4.ANTI ELEVATION SYNDROME
Restriction of elevation of the eye in adduction following IO anteriorization.
Occurs more commonly in patients with IO placement more than 1 mm
anterior to the insertion of IR muscle.
Avoid inserting IO anterior to IR insertion.
Keep the two corners of IO insertion close to each other to avoid lateral
spreading of IO fibres.
Rx- Surgery to disinsert or recess the IO muscle tendon.[10]
CASE DISCUSSION
. A 5 year old girl presented with V pattern exotropia with both eyes IOOA
+2.
.
. The measurements were 45 PD BI in UG , 35 PD BI in PP and 25 PD BI in
downgaze.
.
. BE IO recession at Parks point and LEFT eye LR recession 7.5 mm and MR
Resection 5.5 mm was planned.
.
. Intraoperatively,left IO pulled was into two while suturing.
.
. The torn muscle end was secured with 6-0 suture and sutured back at
Parks point.
.
. On POD 1, LHT 5* was noticed
.
. Child had vertical diplopia.
.
. Post Operative patching 1:1 was advised..
. Diplopia persisted even after 6 weeks.
.
. On post-op 6th week the measurements were 20 PD L/ R in PP, 20 PD L/R
with 4 PD BI in upgaze and 20 PD L/ R with 2 PD BO was found in
downgaze.
.
. V pattern with LE IO Overaction +2 arose suspicion of intact IO in left eye.
.
. Second surgery of IO exploration was done and 2/3 rd of IO belly was
found to be intact.
.
. IO myectomy with SR recession 5 mm done.
.
. Post second surgery the child had no squint or any diplopia.
Prior to surgery Post first surgery
After second surgery
REFERENCES
[1]Olitsky SE, Coats DK. Complications of Strabismus Surgery. Middle East Afr J Ophthalmol. 2015 Jul-Sep;22(3):271-8. doi: 10.4103/0974-9233.159692. PMID: 26180463;
PMCID: PMC4502168.
[2]I. Hashim, C. Al-Haddad, Scleral Perforation as a Complication of Strabismus Surgery: A Literature Review, J Pediatr Ophthalmol Strabismus. (2021) 1–10.
https://doi.org/10.3928/01913913-20211019-02
[3]D.K. Coats, S.E. Olitsky, eds., Scleral Perforation and Penetration, in: Strabismus Surgery and Its Complications, Springer, Berlin, Heidelberg, 2007: pp. 211–221.
https://doi.org/10.1007/978-3-540-32704-2_21.
[4]D.K. Coats, S.E. Olitsky, eds., Slipped and Lost Muscles, in: Strabismus Surgery and Its Complications, Springer, Berlin, Heidelberg, 2007: pp. 233–246.
https://doi.org/10.1007/978-3-540-32704-2_23.
[5]E.M. Ellis, M. Kinori, S.L. Robbins, D.B. Granet, Pulled-in-two syndrome: a multicenter survey of risk factors, management and outcomes, J AAPOS. 20 (2016) 387–391.
https://doi.org/10.1016/j.jaapos.2016.06.004
[6]D.K. Coats, S.E. Olitsky, eds., Postoperative Infection, in: Strabismus Surgery and Its Complications, Springer, Berlin, Heidelberg, 2007: pp. 223–232.
https://doi.org/10.1007/978-3-540-32704-2_22.
[7]Merino, I. Blanco, P.G. de Liaño, Fat adherence syndrome following inferior oblique surgery: Treatment and outcomes, J Optom. 9 (2016) 240–245.
https://doi.org/10.1016/j.optom.2015.07.002.
[8]E.M. Pacheco, D.L. Guyton, M.X. Repka, Changes in eyelid position accompanying vertical rectus muscle surgery and prevention of lower lid retraction with adjustable surgery,
J Pediatr Ophthalmol Strabismus. 29 (1992) 265–272. https://doi.org/10.3928/0191-3913-19920901-03.
[9]B.J. Kushner, Intractable diplopia after strabismus surgery in adults, Arch Ophthalmol. 120 (2002) 1498–1504. https://doi.org/10.1001/archopht.120.11.1498.
[10]Kushner BJ. Restriction of elevation in abduction after inferior oblique anteriorization. J AAPOS. 1997 Mar;1(1):55-62. doi: 10.1016/s1091-8531(97)90024-0. PMID: 10530986.
