STUDY OF TYMPANOMASTOIDECTOMY UNDER LOCALANAESTHESIA USING BUPIVACAINE

Sundar Singh, Asstt. ProfessorGovt. Medical CollegeRajendra HospitalPatiala, Punjab 147001

The study was conducted on 100 patients who underwent tympanomastoidectomy operationsunder local anaesthesia. The anaesthetic agent employed was bupivacaine 0.5 percent with1:2,00,000 epinephrine. The anaesthetic was found to be safe, economical and reliable.Monitoring of facial nerve with minimal bleeding have been its advantages, with no significantcomplications.

INTRODUCTION

Tympanomastoidectomy, operation foreradication of disease process from middle earcleft and reconstruction of sound conductingmechanism of middle ear is one of the highlyskilful, time consuming, but rewarding opera-tion performed in t he practice of otolaryngology.While doing tympanomastoidectomy one desiresthat the bleeding should be minimal, graft andprosthesis should remain in place, operativeand post-operative complications should beminimum and facial nerve injury could be monitoredduring operation. But these ideal conditions arenot possible if operation is performed undergeneral anaesthesia.

Local anaesthesia is widely used inotolaryngological practice. Whitaker et al. (1947)used nerve block anaesthesia for fenestrationand mastoidectomy operations. Shambaugh andhis associates (1967) preferred local anaesthesiawith adequate pre-operative sedation for nearlyall temporal bone operations. Lignocaine is mostcommonly used in most of the cases. Although

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lignocaine when used alongwith epinephrinecan provide a relatively bloodless field, but itsduration is not sufficient for long procedureslike tympanomastoidectomy.

Bupivacaine an amide-type of local anaesthetic l i

during synthesized by Ekenstam and hiscolleagues in 1957 and used clinically by Telivuo'in 1963, has a longer duration of action. It isfour times more potent than lignocaine and itsduration of action lasts for five to sixteen hours.A clinical trial with 0.5 percent bupivacaine (with1 in 2,00,000 epinephrine) as local anaestheticwas undertaken to evaluate its efficacy, doseschedule and safety in time consuming opera-tion of tympanomastoidectomy.MATERIAL AND METHOD

One hundred patients in the age group of18-45 years suffering from chronic suppurativeotitis media underwent tympanomastoidectomyunder local anaesthesia in the Department ofEar, Nose and Throat attached to GovernmentMedical College, Patiala, and Amritsar. Atro-pine 0.6mg and pentazocine 30 mg was givenintramuscularly as pre-medication forty-five minutes-prior to the operation. Diazepam 10 mg intra-venously was given just before the start ofoperation.

Bupivacaine 0.5 percent with 1:2,00,000epinephrine was used as local anaesthetic.

TECHNIQUE OF INFILTRATION ANAESTHESIA

As both techniques end-aural and post-auralwere included in the study, the following methodwas used for infiltration for post-aural and end-aural incisions.

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Study of Tympanomastoidectomy under Local Anaesthesia Using Bupivacaine — Sundar Singh

1. Tympanic branches of auriculo-tempo-ral (V) to the anterior meatal wall andtympanic membrane were blocked byinfiltration of 1 or 2 ml of solution into anteriormeatal wall at the junction of cartilaginous andosseous meatus. The auricular branches of thisnerve to the upper part of auricle and skin abovethe meatus were blocked by injection of 1 mlof solution at several points into the skin andperitosteum of incisura-terminalis upward toupper attachment of the auricle.

2. The branches of greater auricular (C 3)

were blocked by injection of 1 ml ofsolution at several points behind the auricleover the mastoid process.

3. The auricular branch of vagus nerve (x)was blocked by injection of periosteum of an-terior surface of mastoid process and of skinof the floor of meatus.

In some patients who felt pain or discomfortwhen tympanic muco-periosteum was interferedwith, 2 percent lignocaine was instilled intympanic cavity or applied to tympanic mucosawith soaked cotton pledgets.

After injection of local anaesthesia theobservations regarding onset of surgicalanaesthesia, facial nerve monitoring, bleedingand pain felt by the patient were recorded duringthe operation.

Blood pressure, pulse, facial nerve palsy,nausea, vomiting, vertigo, nystagmus and timeof first pain felt by the patients were recordedpost-operatively for the next twelve hours.

(OBSERVATIONS

The present study comprised of both sexesin the age group of 18-45 years. Maximumnumber of patients were in the age group 18-25 years.

The average dose of bupivacaine used toobtain surgical analgesia was 75 mg (15 cc of0.5 percent). Average onset of surgical anaesthesiawas 4.3 minutes after local injection. Meanduration of Surgery was two hours. The meanduration for the requirement of analgesic inpost-operative period was 4.82 hours, with rangefrom immediately after surgery to more thantwelve hours.

None of the patients experienced nausea orvomiting during the operative procedure (Table

I). One patient had vertigo and nystagmus duringoperation. Seven patients had nausea and vom-iting in post-operative period with five havenystagmus, with mean onset of 3.8 hours in thepost-operative period.

These symptoms subsided completely withintwentyfour hours without any treatment.

Bleeding did not cause much problem ex-cept in two cases.

Facial nerve palsy was observed in two casesonly. It was noticed following local infiltrationof bupivacaine within ten minutes and paresisrecovered fully within two-three hours. Onlyfour patients felt pain and three others felt mildache during operation.

Bupivacaine was not found to be effectivetopically. In few cases in which middle earmucoperiosteum needed to be anaesthetized,it was done with instillation of 2 per cent lignocainedrops or application with cotton pledgets.

Blood pressure and pulse did not show anysignificant change.

DISCUSSION

Local anaesthesia apart from preventing thecomplications of general anaesthesia is spe-cially useful in tympanomastoidectomy opera-tions. Not only the bleeding is minimal, theingress of nitrous oxide in the middle ear duringgeneral anaesthesia is avoided with preventsthe dislocation of graft and ossicles. The effu-sion in the middle ear because of negativepressure as a result of rapid absorption ofnitrous oxide after operation is also prevented.The other advantage of local anaesthesia is thatthe improvement in hearing can be tested duringthe operation itself.

The facial nerve monitoring can also be donethroughout the operation thus relieving the Surgeonof the tension of the complication. Local anaesthesiais also economical. The patient can be senthome the same day. The cost factor is impor-tant in the third world and developing countries.

In the present study bupivacaine was foundto be safe and effective local anaesthetic intympanomastoidectomy operations.

The average onset of surgical anaesthesiawas 4.3 minutes. Lund et al. (1970) reportedaverage onset of surgical anaesthesia to befour minutes in brachial plexus nerve block withbupivacaine.

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Study of Tympanomastoidectomy under Local Anaesthesia Using Bupivacaine — Sundar Singh

A dose of 75 mg (15 cc of 0.5 percent)bupivacaine with 1:2,00,000 was sufficient toproduce surgical anaesthesia, which is well withinthe safe limit of 2mg/kg body weight, Moore etal. (1979) used upto 600 mg of drug in periph-eral nerve blocks without any systemic toxicreactions.

Lignocaine although effective has a shorterduration of action as compared to bupivacaine.Bupivacaine not only has longer duration ofaction, it is fourtimes more potent than lignocaine.In the present study, mean time of onset of painafter surgery was 4.82 hours. Maimon et al.(1984), in facial plastic surgery, observed thatmean onset of pain after the surgery was fivehours with range from 1-12 hours.

The only disadvantage with bupivacaine isthat it is not effective topically unlike lignocainein the middle ear cavity. In cases where middleear mucoperiosteum is to be anaesthetised, ithas to be done with lignocaine drops orapplication with cotton pledgets. Violaris et al.(1989) observed this during his study oftopical used of bupivacaine in post-operativetonsillectomy cases.

There were no systemic toxic reactions. Theonly other complication encountered in this serieswas transient facial nerve palsy in two casesfollowing infiltration of bupivacaine near themastoid tip area in the vicinity of facial nerve.The onset of this palsy was within ten minutesand the average duration was 2.30 hours. GerardMedden (1989) observed that facial nerve recoveryoccurred within seventy minutes of initialobservation after 2 percent lignocaineinfiltration. Recovery occurs earlier in case of

REFERENCES

lignocaine as it is short acting local anaesthetic.

It is advisable to look for facial nerve integ-rity before starting the operation. The paresisresulting from local infiltration is transient andfully recovers.

Vertigo and vomiting occurred in seven caseswith five cases having nystagmus in the post-operative period. Roy et al. (1975) used bupivacainein spinal anaesthesia and observed no nauseaand vomiting. These symptoms recovered fullywithin twenty four hours and were probably dueto vertibular stimulation during operation andnot because of any systemic toxic reaction.

Sensorineural loss due to vibratory effectsof burr and manipulation of ossicular chain wasnot observed in this series. But this complica-tion can also occur even if the operation is doneunder general anaesthesia.

Bupivacaine is safe, effective and economi-cal for tympanomastoidectomy. In view of theabove mentioned advantage its use is recom-mended routinely for all patients requiringtympanomastoidectomy. The only snag with localanaesthesia is that it cannot be used in children.

CONCLUSION

Local anaesthesia has many advantages overgeneral anaesthesia in ear surgery. Bupivacaineis an effective local anaesthetic and providessatisfactory anaesthesia for long operatingprocedures like tympanomastoidectomy. Surgi-cal analgesia is achieved with average of morethan four hours. It can be used safely with noclinical evidence of systemic toxicity.

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2. Maimon, W.N., Schuller, David E. (1984) : Lidocaine and bupivacaine in facial plastic surgery. Aclinical trial. Archives of Otolaryngology 110(8): 525-526.

3. Moore, D.C., Mather, L.E., Bridenbaugh, LD., Thompson, G.E., Balfour, R.I., Lysons, D.F., andHorton, W.G. (1977) : Bupivacaine (Marcaine): An evaluation of its tissue and systemic toxicity inhumans. Acta. Anaesthesia Scand. 21; 109-121.

4. Roy, A.K., Multani, Sudha, T., Lala, M.N.(1975) : A comparative study of Bupivacaine (Marcaine)Mepivacaine (Carbocaine) and Lignocaine (Xylocaine) in Spinal Anaesthesia. Indian Journal ofAnaesthesia, 23: 60-67.

5. Shambaugh, G.E. (1967) : "Surgery of the Ear". Philadelphia, W.B. Saunders Company, Page 166.6. Violaris, N.S., Leftoner Tuffin, J.R. (1989) : Can Post-tonsillectomy pain be reduced by topical

bupivacaine? Double blind controlled trial. Journal of Larynogology and Otology. 103 : 592-593.7. Whitaker , C.F., Juers, A.I. and Shambaugh, G.E., Jr, (1947) : A modified endaural incision with

nerve block anaesthesia for fenestration and mastoidectomy. Aarchives of Otolaryngology; 45: 662.

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