354 >

clinical review

Ocular complications with dental

local anaesthesia – a systematic
review of literature and case report

SADJ September 2015, Vol 70 no 8 p354 - p357

P Ravi1, G Gopi2, S Shanmugasundaram3, KK Raja4

ABSTRACT INTRODUCTION
Introduction: Intraoral local anaesthetics are commonly The delivery of local anaesthetics is one of the most wide-
administered in Dentistry and may be associated with com- spread procedures in dentistry and is vital to achieving pain
plications. Although ocular complications are rare they may control and cooperation in the dental patient. Although it
occur with both maxillary and mandibular injections. is usually a safe procedure, several complications have
been associated with its use. These complications can
Materials and methods: A database search was carried either be localized, such as trismus and infection, or sys-
out in Pubmed and Ovid MEDLINE using the keywords: temic, such as anaphylaxis and reactions to overdose.
ocular/ophthalmic/visual, dental anaesthesia/local anaes- Ophthalmic complications are relatively rare and account
thesia and complications/paralysis. Each case report was for 0.04 to 0.1% of all complications.1,2 The most common
analyzed for age and sex of the patient, type of anaes- complications include diplopia, amaurosis, ophthalmople-
thesia given, the anaesthetic and vasoconstrictor used, gia, ptosis and mydriasis.3 These are mostly transient. Per-
quantity given, onset and duration of complications, and manent complications are exceedingly rare and very few
type of complications. 140 case reports were included. cases have been reported in the literature. Nevertheless,
The data were recorded on a data extraction form and it is essential that the dentist be aware of such complica-
statistically analyzed. tions in order to diagnose and manage them effectively,
and where applicable, to refer them without delay.
Conclusion: Complications occurred more frequently in
females, and in the age range 20-40 years old. The type of
The purpose of this study was to review the literature re-
complication was specific to the technique used. Although
porting on ocular complications associated with dental
rare, such complications are distressing and the clinician
local anaesthesia and to analyze whether such complica-
must be alert to the possibility in order to minimize occur-
tions were related to a specific common variable such as
rences and to be able to reassure patients.
technique or drug used. A case report is also presented.
Keywords: dental anaesthesia, ocular complications, di-
plopia, amaurosis MATERIALS AND METHODS
An electronic database search was carried out in Pubmed
and Ovid MEDLINE. The combinations of keywords used
included: ocular/ophthalmic/visual, dental anaesthesia/
1. P Ravi: MDS, MOMSRCPS. Senior Lecturer, Department of Oral
and Maxillofacial Surgery, SRM Dental College, Bharathi Salai,
local anaesthesia and complications/paralysis. A manual
Ramapuram, Chennai – 600089, India. search was also carried out using the reference lists of se-
2. G Gopi: MDS. Senior Lecturer, Department of Oral and Maxillofacial lected articles. Abstracts of all the selected articles were
Surgery, SRM Dental College, Bharathi Salai, Ramapuram, Chennai screened and only those articles which specifically de-
– 600089, India. scribed cases of ocular alterations following dental anaes-
3. S Shanmugasundaram: S. MDS, FIBOMS. Professor, Department thesia were chosen. Reviews of literature were excluded.
of Oral and Maxillofacial Surgery, SRM Dental College, Bharathi
Salai, Ramapuram, Chennai – 600089, India. Each case report was analyzed for the following parame-
4. KK Raja: MDS. Professor and Head of Department, Department of ters: age and sex of the patient, type of anaesthesia given,
Oral and Maxillofacial Surgery, SRM Dental College, Bharathi Salai, the anaesthetic and vasoconstrictor used, quantity given,
Ramapuram, Chennai – 600089, India. onset and duration of complications, and types of com-
Corresponding author plications that occurred. Details of needle gauge, length
P Ravi: and aspiration done prior to procedure were also noted if
Ravi, 16/57 Balaji Nagar 1st Main Road, Ekkatuthangal, Chennai – mentioned in the case report. All details were recorded on
600032, India. Tel: +91 938 105 0242 E-mail: drpoornimaravi@gmail.com
a data extraction form for statistical analysis.
www.sada.co.za / SADJ Vol 70 No. 8
clinical review <
355

RESULTS eye. The eyelid was propped open with a finger, following
From 1936 to 2014, a total of 140 cases have been reported which it was noticed that the eyeball had become com-
in the literature, including the one presented in this report. pletely fixed. After five minutes, the patient could keep the
Ocular complications were more frequent in females (63.5%) eye open without assistance and eye movements returned
as compared with males (36.4%). The age of the patients to normal in all planes except for adduction, which returned
ranged from 4 years to 73 years (mean 38.5 years), the ma- to normal in 30 minutes. No blanching of the skin or loss
jority being between 20 and 40 years of age (56.4%). of accommodation was noted. As the patient was appre-
hensive, it was decided not to proceed with the extraction.
Although several techniques have been associated with ocu- The patient was discharged after observation for one hour.
lar complications, the commonest technique was the inferior Follow-up after two days revealed no further complications.
alveolar nerve block (54.2%), followed by the posterior supe- The procedure was then carried out uneventfully.
rior alveolar nerve block (30%). The commonest anaesthetic
drug used was lignocaine (68%), followed by articaine (18.5%). DISCUSSION
Few cases utilized mepivacaine (5%), procaine (5.8%), prilo- Ocular complications following local anaesthesia are un-
caine (1.6%) and butethamine (0.8%). 90.7% of these agents common and the frequency is estimated to be 1 in 1000.3
contained a vasoconstrictor. The commonest vasoconstrictor They can, however, cause considerable anxiety to both
was epinephrine in a dilution of 1:100000 (64.7%). the patient and the clinician. From the patient’s point of
view, this is a totally unexpected event and may be ex-
The frequency of ocular complications is given in Figure 1.
tremely alarming. The clinician, if not acquainted with the
It was noted that most symptoms were technique-specific.
nature of these complications, may fail to diagnose such
Symptoms more specific to maxillary techniques included
an incident,5 and may even attribute it to a more serious
diplopia (74.7%), lateral rectus palsy (81.8%), mydriasis
event, like a transient ischemic attack.6 It is therefore es-
(73.3%) and ptosis (76.6%). Amaurosis was more common
sential that the clinician understand the etiology and path-
in mandibular blocks (84.6%), as were blanching (90%) and
ogenic mechanism of these complications.
blurred vision (72.7%). These results are in accordance
with findings reported in previous literature reviews.2-4 It
There has been no agreement on the exact pathway that
was noted that all cases that reported blanching had used
leads to these manifestations. The following theories are
epinephrine as a vasoconstrictor.
currently accepted:
Only half the cases reported mentioned onset of action.
Most of these had immediate onset of action (20.9%) or Intra-arterial route:
within a few seconds(8%) or minutes(41.9%). Only 3% had Intravascular injection appears to be the main cause for
late onset of more than 24 hrs. There was no correlation these manifestations following mandibular nerve blocks.
between anaesthetic technique and onset of action. The inferior alveolar artery and vein lie in close proximity
to the nerve within the inferior alveolar canal. Even if the
In more than half the cases, symptoms resolved within 30 initial aspiration is negative, as was mentioned in twelve
minutes (57.1%). Even in cases where anaesthetics with longer cases of inferior alveolar nerve blocks, slight movement of
duration of action were used, symptoms resolved within 120 the patient or operator could result in inadvertent injection
minutes. In 7.1% of patients, symptoms lasted for few days to into the artery. It is hypothesized that under pressure, the
weeks. 5.5% of patients had 70
permanent symptoms. There
was no correlation between
technique used or quantity of 60
anaesthetic used and dura- Maxillary
tion of symptoms. Mandibular

50
CURRENT CASE
REPORT
The present case involved a 40
30 year old healthy woman
who reported to our hos-
pital for routine extraction 30
of the left mandibular third
molar. Local anaesthetic
was administered by a post- 20
graduate student, using 2%
lignocaine with 1:80000
adrenaline. Aspiration was 10
negative and the student
proceeded to inject the lo-
cal anaesthetic solution. 0
Less than 0.5ml of the so-
on
g
s

ia

in

is

a
ls

ls

ls
si

si

lution had been injected

gi
in

os
op

pa
si
ro

pa

pa

pa

ria

le
ch

vi

pt
pl

op
e
au

yd

when the patient suddenly

an

LR

SQ
ey
di
re
am

lm
m
bl

ur

complained of loss of vision

ha
bl

ht

and inability to open the

op

Figure 1: Frequency of symptoms specific to technique

356 > clinical review

local anaesthetic solution is forced back into the maxillary Intravenous injection
artery. It has also been reported that in 37% of the popula- It has been suggested that inadvertent intravenous injections
tion, the maxillary artery loops downwards, lateral to the could reach the cavernous sinus via the pterygoid plexus and
lingual and inferior alveolar nerves. Hence direct injection anesthetize cranial nerves III, IV and VI as described earlier.
into the maxillary artery is also possible.7,8 The posterior superior alveolar nerve block is most likely to
cause this, as even a minor change in position and depth of
The anaesthetic solution may pass from the maxillary ar- the needle could pierce the pterygoid plexus.19,20
tery into the middle meningeal artery or accessory middle
meningeal artery. The middle meningeal artery is believed Autonomic dysregulation
to anastomose with the ophthalmic artery, and in some Several cases of ocular complications occur despite nega-
cases the ophthalmic artery may even arise as a branch tive aspiration. Kronman et al suggested an alternate hy-
of the middle meningeal artery.6,9 pothesis.21 Each artery is surrounded by a delicate sym-
pathetic plexus. Trauma to either the inferior alveolar or
Amaurosis
posterior superior alveolar arterial wall could occur by the
The central artery of the retina arises from the ophthalmic
anaesthetic needle scraping against it. This sets up an im-
artery. If the local anaesthetic passes into this vessel, it
pulse that travels through the plexus on the maxillary artery,
may result in transient amaurosis.9 In seven case reports,
via the deep petrosal nerve and internal carotid plexus to
amaurosis was permanent. The mechanism behind per-
the ophthalmic artery. This hypothesis is supported by the
manent amaurosis is unclear. It has been suggested that
reflex vasospasm of the central retinal artery could result phenomenon of blanching in some cases,22 Campbell et al
in ischaemia and necrosis of the retinal tissue, causing theorized that in their case, the stellate ganglion could have
permanent amaurosis.10 It was also suggested that oil been accidentally blocked by diffusion through the fascial
embolism could have occurred following intravascular in- planes.23 This mechanism could account for manifestations
jection of fat-based local anaesthetics.11 While the anaes- of miosis and enophthalmos seen in certain cases.24
thetic used is not mentioned in five cases, two report the
use of procaine hydrochloride.12,13 Most authors agree that the likeliest mechanism is the
intravascular route. There are, therefore, several ways in
The choroidal vessels that supply the retinal cones also which such complications can be prevented. It is advisable
derive their blood supply from the ophthalmic artery. If to use self aspirating syringes. In case non-aspirating
these vessels were affected, it could affect the colour vi- syringes are used, double plane aspiration must be
sion. The ‘purple haze’ described by Scott et al may have performed, and subsequent movement of the patient and
been precipitated by this mechanism.14 operator must be avoided. The anaesthetic solution must
be injected slowly, giving a full cartridge over a period
Diplopia and extraocular muscle palsy: of 60 seconds. This would avoid injecting the solution
The ophthalmic branch of the middle meningeal artery may under pressure. Anatomical landmarks must always be
anastomose with the lacrimal artery that supplies the lateral visualized prior to injection, especially in paediatric cases,
rectus muscle. The anaesthetic may, therefore, reach the lat- where the mandibular foramen would be at a higher level.
eral rectus muscle, paralyzing it. It was noted that lateral rec-
tus appeared to be the most frequently paralyzed muscle. The gauge of needle used for injection may play an
important role in these complications. Firstly, smaller
The accessory meningeal artery has terminal branches gauge needles are more likely to be deflected as they pass
within the cavernous sinus.15 The III, IV and VI cranial through tissues; secondly, a few studies have shown that
nerves are all located within the sinus and may become aspiration of blood is more reliable through a larger lumen.
anaesthetized by the anaesthetic being carried into the Thirdly, it is likely that the anaesthetic may be injected
cavernous sinus. This could be responsible for palsy of the under greater pressure when the lumen is smaller, hence
other extraocular muscles. Palsy of the third nerve would chances of backflow are greater. Malamed stated that
also lead to mydriasis, ptosis and loss of accommodation. the 25-gauge needle is preferred for all injections where
the risk of positive aspiration is high.25 Although only 32
Local diffusion:
cases in this review have mentioned the needle gauge,
This is the probable mechanism for ocular manifestations
following maxillary nerve blocks. Over-insertion of the needle 41% of these (13 cases) have used needle sizes narrower
during a posterior superior alveolar nerve block could result than 25-gauge. It is also important to control the depth
in direct diffusion of the anaesthetic solution from the ptery- of insertion as over-insertion would increase the risk of
gopalatine fossa to the orbit via the inferior orbital fissure. penetrating a vessel and also increase the risk of the
The abducent nerve lies nearest to the fissure and hence the anaesthetic spreading by local diffusion.
most commonly affected muscle is the lateral rectus, which
Once an ocular complication has occurred, the guidelines
accounted for 66.6% of all palsies.16 It was noted that in 60%
recommended by Lee, Van der Bijl and Boynes may be
of posterior superior alveolar blocks given (18/30 cases), ar-
followed.4,26,27 The first and most important step is to
ticaine was used, which is believed to have superior diffusion
properties. The use of longer needles and increased depth reassure the patient. The affected eye may be covered with
of insertion may also be a factor. While most cases do not gauze till the symptoms subside, and the patient must be
mention the depth of insertion, Kini et al have stated that they escorted home, as monocular vision prevents the patient
used a 1.5 inch needle (38mm).17 from judging distances. If the symptoms persist for longer
than six hours, consultation with an ophthalmologist is
In the case of greater palatine nerve blocks, and maxillary mandatory. In most of the cases, clinicians have proceeded
blocks through the greater palatine canal,18 it must be noted with the dental procedure despite the ocular symptoms.
that the greater palatine canal opens to the inferior surface There is no harm in performing the procedure, however, if
of the pterygopalatine fossa and solution may diffuse from the patient is anxious, it may be desirable to postpone the
here to the orbit. procedure to the next visit.
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clinical review <
357

Conflict of interest: None declared 13. Sokolic P: Clinical contribution to retinal tele-trauma. Med Arh
1960; 14: 37-43.
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2. Aguado-Gil JM, Barona-Dorado C, Lillo-Rodríguez JC, De La 15. Fish LR, McIntire DN, Johnson L. Temporary paralysis of cra-
Fuente-Gonzáles DS, Martínez-Gonzáles JM. Ocular compli- nial nerves II, IV and VI after a Gow-Gates injection. J Am Dent
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tistry. Dent Clin N Am 2010; 54: 677–86. plications associated with maxillary nerve block anaesthesia
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