Medicine

Diplopia as a complication of local anesthesia:A case reportFanny Koumoura, DDSVGeorge Papageorgiou,

Dipiopia caused by iocai anestbesia at the superior posterior alveolar narve for the removai of themaxiilary third molar is a rare compiication. The dipiopia is due to facial paisy of the oculomotor muscles otthe globe.Thispaper describes the case Ota 22-year-oid woman, in whom dipiopia was observed atter anoverail uncompiicated removai of the semi-impacted third moiar. Possibie causes of the anesthetic effectsare reported. The most accepted expianation is that the anesthetic diffuses on the abducent nerve in thecavernous sinus. The necessary actions fhaf the dental surgeon musf perform are reported.(Quintessence tnt 2001:32:232-234)

Key words: abducent nerve, cavernous sinus, dipiopia, impacted third molar, infrafemporai fossa, iaterairecfus muscie, iocai anesthesia

The local anesthesia that is frequently used in dentalpractice is occasionally accompanied by some

complicafions tbat are either systemic (beadache, syn-cope, failure of tbe anesthesia, nausea)' or local(bematoma, facial palsy, anemic skin zones).

Tbus, during tbe administration of regional anestbe-sia to tbe second branch of tbe trigeminal nerve, sev-eral unusual sensory or motor disorders may occur,such as blanching of tbe cheek or amaurosis, orophthalmoplegia, resulfing in diplopia.-

Diplopia is a disturbance of eye movement, result-ing in double images at a certain position, caused bytbe suppression of tbe oculomotor muscles that con-trol tbat posifion. Tbe suppression is caused by eitberinjury to the III, IV, and VI cranial nerves that inner-vate tbose muscles or direct injuries to tbe musclesthemselves.^ An indireet effect on one of tbe ocularmuscles may occur during anestbesia of tbe maxillarynerve via tbe greater palatine eanal,'' tbe infratemporalfossa, or tbe infraorbital sulcus.̂

CASE REPORT

The patient in this report experienced postoperativedipiopia. The 22-year-oid woman attended the

'Maxiliolaciai Sjrgeon and Associate Director, Maxiiiofaciai Department,General Peripherie Accidents iHospital ("KAT'), Kifissia, Athens, Greece

'Maxiiiofaciai Sjrgeor, General Periplieric Accidents Hospilai ("KAT"),Kifissia, Athens, Greece.

Reprint requests; Or Fanny Koumoura, 21 Eveipidcn Street, Athens 11362, Greece. E-maii: dpap@hol.gr

This paper was presented al the 18tti Parhellenic Dentai Ccngress, AthensGreece. October 26,1998.

Maxiiiofaciai Surgery Department for the removal ofthe semi-impacted maxillary left third molar. Thepatient had no apparent health problems, and thetootb was situated in a perpendieular posifion [B classper Archer). A solution of artieaine hydrochloridev/itb epinepbrine bydrochloride was injected, and thetooth was elevated uneventfully. Immediately after theremoval of the tooth, the patient complained of "dou-ble vision"; no other symptoms or signs were mani-fested. The ensuing orthoptic evaluafion revealed tbatthe patient was seeing double only at tbe outer leftpositions of her eyes. Gradually, her vision improvedand recovery was completed approximately 2 bourslater, requiring no further treatment.

DISCUSSION

The superior posterior alveolar nerves etnerge fromthe maxillary nerve before entering the maxilia. Themaxillary nerve is a brancb of tbe trigeminal cranialnerve. For tbe removal of maxillary third molars, anes-thetic solution is usually deposited bebind the maxil-lary tuberosity near wbere tbe superior posterior alve-olar nerve passes tbrougb tbe pterygozygomatic andinfratemporal fossae.

The pterygozygomatic fossa and its continuity, theinfratemporal fossa, are located in the space boundedby the zygomatic arch, the maxillary tuherosity, thezygomatie process of the maxilla, and the greater wingof the sphenoid bone, Tbis space contains several ves-sels and nerves, including the internal maxillary andmiddle meningeal arteries, the pterigoid venousplexus, and the third brancb of tbe trigeminal nerve.Tbe bilateral fossae communicate througb tbe inferior

232 Voiume 32, Number 3, 2001

Koumoura/Papageorgíou •

Fig 1 Possibie routes of affectation of oouiomotor muscles, (a]difect diffusion through the soft tissues; (b) venous routes via thecavernous sinus; (c) arterial route via an abnormai course; (d)arteriai route «iattie middle meningeai artery.

Fig 2 Cavernous sinus and cranial nerves in transverse section:(a) internal carotid arrery; (b] oculomotor nerve; (c) troctilearnerve, (d] abducent nerve, (e¡ ophthaimic nerve; (f¡ maxiliarynerve; (g) spiienoid sinus; (in¡ seila turcioa.

orbital fissures with their respective orbital fossae,where the oculomotor muscles are located.

In the case of regional anesthesia, the anestheticsolution can diffuse into the ocular muscles causingsubsequent diplopia.- The reported cause is by directdiffusion of the solution through the soft rissues oreven the connective tissue along the nerves and thevessels (Fig la).'

The possibility of anesthetic solution penetraringthe orbital fossa via an anatomical defect of the maxil-lary sinus wall was also considered.^

The suggestion of arterial diffusion was also dis-cussed (Fig lc). The anesthetic solufion enters throughthe superior posterior alveolar artery, which is runningthrough a specific anomalous anatomical course, andreaches the oculomotor muscles.^ We can consider asecond artedal course (Fig Id) to be from the entranceof the solution at the superior part of the internal max-illary artery to the middle meningeai artery, which hasan anastomotic link with the lacrymal branch of theophthalmic atlery, and to the muscles. In this lattersuggesfion, however, several other symptoms such asdizziness and sensitivity of the eyelids exist.̂

Finally, according to the venous diffusion concept(Fig lb), the anesthetic solution from the pterygozygo-matic-infratemporal fossa enters the pterygoid venousplexus, and via emissary veins through the ovoid, thelacerum, or the sphenoid foramina reaches the cav-ernous sinus of the cranial base, where it soaks the

abducent nerve (VI cranial nerve),' causing neuro-paralysis of the lateral rectus muscle. This muscle issolely innervated by the abducent nerve, and in thecase of interruption of its function, the result isdiplopia at the lateral posifion of the eye.*"

The patient's diplopia was initially attributed to thedirect spread through the surrounding tissues. If this isthe case, the patient should see a double image at mul-tiple posifions because the anesthetic that enters theinferior orbital fissure should affect all the muscles ofthe orbital fioor. For example, affectation of the infe-rior rectus and inferior oblique muscles createsdiplopia in more than one position of the eye. Thiscase, however, specifically concerned the lateral posi-tion, which is controlled by the lateral rectus muscleand its nerve, tbe abducent nerve. Consequently, itseems that the anesthetic affected the abducent nervebecause it is impossible to specifically affect the lateralrectus muscle only. Indeed, the abducent nerve, run-ning supedicially on the lateral wall of the cavernoussinus (Fig 2), lateral to the internal carotid artety, isseparated by the dura mater from the rest of the ocu-lomotor nerves. These nerves, the oculomotor,trochlear (III and IV cranial nerves), and tdgemlnal(ophthalmic and maxillary) nerves, are thus protectedwhen the anesthefic enters the sinus."

Consequently, the venous spread of the anestheticand the isolated effect on the abducent nerve is themost likely explanation in this case.

Quintessence Internaticnal 233

• Koumoura/Papageorgiou

CONCLUSION

Few case reports are mentioned in the world literatureconcerning diplopia. In tiie instance of diplopia, wemust reassure tbe patient by expiaining tbe transientnature of tbe problem, tbat its duration lasts as long astbe anesthesia. As soon as this compiication appears,an examination must be performed to assess eyemobility, pupil reaction, and the visual acuity, in orderto determine tbe probable cause and to prevent thepossibility of furtber damage.

REFERENCE

1. Hidding J, lihoury R General complications in dental localanesthesia. Deutsche Zahnarztliche Zeitschrift 1991:46:834-836.

2. Goldenherg AR. Transient diplopia from a posterior alveo-lar injection. J Endod 1990;16:550-551.

3. Rubin M. Trocblear nerve palsy simulating an orbitalblowout fracture. J Maxillofac Surg 1992:50:1238-1239.

4. Sved AM, Wong JD, Donkor P, Horan J, Rix L, Curtin ),Vickers R. Complications associated with maxillary nerveblock anaesthesia via the greater palatine canal. Aust Dent J1992:37:340-345.

5. Apinhasamit W. Diplopia following infiltration injection ofthe upper canine tooth (a case report]. J Dent Assoc Thai1983:33:113-118.

6. Wrinkler T, Von Wowern N, Odont L, Sittniann S. Retrievalof an upper third molar from the infratemporal space. J OralSurg 1977 ;35:130-I32.

7 Marinho R. Abducent nerve palsy following dental localanalgesia. BrDentJ 1995:179:69-70.

234

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