Analysis of the retroauricular transmeatal approach: a novel transfacial access to the mandibular skeleton

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BritishJournalofOralandMaxillofacialSurgery50(2012)e22–e26

Analysis

of

the

retroauricular

transmeatal

approach:

a

novel

transfacial

access

to

the

mandibular

skeleton

Francesco

Arcuri

∗

,

Matteo

Brucoli,

Arnaldo

Benech

DepartmentofMaxillo-FacialSurgery,AziendaOspedalieraMaggioredellaCaritàUniversityofPiemonteOrientale“AmedeoAvogadro”,Novara,Italy

Accepted20August2011 Availableonline15September2011

Abstract

In2005experimentalworkwaspublishedaboutthesuccessfulsurgicalmanagementoffracturesofthecondylarheadthrougharetroauricular

approach.ThereweretworeportsinGerman,andlaterpublicationshavenotmentionedthisroutetoopenreductionandinternalfixationof

suchfractures.TheapproachwasstudiedinGermanybutwaspoorlydescribedandillustrated;laterreportsinEnglishdonotmentionthis

routetothemandible.Theaimofthisstudywastoillustratetheretroauriculartransmeatalapproach,andbrieflytoreviewcurrentsurgical

approachestothemandibularskeletonandtheirtechnicalvariants.Weexposedthemandibularskeletonbyaretroauriculartransmeatalroute

withtransectionoftheexternalear,dissectionoftheparotidgland,isolationoftheretromandibularvein,andprotectionofthefrontalbranchof

thefacialnerveandtheauriculotemporalnervewithinthesubstanceoftheanteriorlyretractedflap.Althoughwecannotdrawanysignificant

conclusions,theretroauriculartransmeatalapproachensuresextremelylowriskofinjurytothefacialnerve,andleavesaninvisiblescar.The

morbidityislowintermsoffacialnervelesions,vascularinjuries,aestheticdeformity,auditorystenosis,salivaryfistulas,sialoceleandFrey

syndrome.Wethinkthatfurtherprospectiveclinicaltrialsareneededbettertoassessandeventuallydevelopthisapproach.

Keywords:Retroauriculartransmeatalapproach;Mandible;Facialnerve

Introduction

In 2005 Neff et al.,1 supported by previous

experimen-tal work,2 published a report of successful management

of fractures of the condylar head through aretroauricular

approach;thesetwomanuscriptswerepublishedinGerman.

The retroauricularapproach hasbeen wellstudiedin

Ger-manpapersbut,tothebestofourknowledge,littlescientific

informationhasbeen publishedinEnglishaboutthis

tech-niqueoritsoutcomesotherthaninthetextbookbyEckeltand

Loukota.3,4 Inthispaperweseektoexpandthedescription

andtoillustratelong-termoutcomes.

∗_{Corresponding} _author _at: _S.C.D.U. _di _Chirurgia _{Maxillo-Facciale,}

OspedaleMaggioredellaCarità,CorsoMazzini18,28100Novara,Italy. Tel.:+3903213733893/3733783/3733895;fax:+3903213733893.

E-mailaddress:fraarcuri@libero.it(F.Arcuri).

Weused theretroauriculartransmeatalapproachtotreat

high fractures of the condylar head. This route is a

rela-tivelysimplewayofgainingdirectaccesstothemandibular

skeleton;itallowsaneasyandfastanatomicalreductionof

thefragmentsandproperosteosynthesiswithminiplatesand

screws, whileminimisingthe risksof injuriestothefacial

nerve,andleavinganinvisiblescar.

The aim of the study was toillustrate the

retroauricu-lartransmeatalapproachandtoreviewthecurrentsurgical

approachesandtechnicalvariantstothemandibularskeleton.

Materialandmethods

We retrospectively reviewed the surgical records of 14

patients (meanage33years;range17–64)whowere

oper-atedonfor condylarfracturesbetween1January2006and

1 December 2008 atthe Maxillofacial Unitof the Novara

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MajorHospital.Weassessedtheretroauriculartransmeatal

approachadoptedforallcases.Thisnewmethodofaccess

tothemandibularskeletonisclearlydividedintoeightsteps

andisfollowedbyillustrations.Ourresearchwasapproved

byourlocalinstitutionalreviewboard.

Surgicaltechnique Preparationanddraping

Withthepatientsupine,undergeneralanaesthesiawith

naso-trachealintubation,andwiththeheadinaneutralposition,

wemarkthemandible,thezygoma,andtheglenoidfossaas

pertinentlandmarksoftheface.

Weprepareanddrapetheentireface;thesterilesurgical

fieldisseparatedfromtheoralandnasalcavitiesbyan

adhe-sivefilm topreventbacterial contaminationatthesurgical

site.Weshavethepreauricularhairandplaceacottonbud

soakedintoantibioticointmentintheexternalauditorycanal.

Markingtheincisionandvasoconstriction

Wemarktheincisionbeforeinjectionof1%lidocaine4–8ml

with1:100,000 adrenalineintheretroauricularareaandin

theposteriorsurfaceoftheexternaleartodecreasebleeding

duringtheoperation. Althoughthe occipitalarea is

vascu-lar,andlocalanaesthesiaimproveshaemostasis,wepreferto

infiltrateasmallamounttoavoiddistortionofthetissues.

Incisionofskinandsofttissue

Wemakeaverticalincision2.5–3cmlonginthe

retroauricu-larregion,about1–1.5cmmedialtothesulcus,throughskin

andsubcutaneoustissue.Theedgesoftheincisionareplaced

0.5–1cmfromthebaseoftheauricularlobuleand0.5–1cm

belowtheinsertionofthehelix.Weraisetheanteriorandthe

posteriorflapsandexcisethemusclefibresandfatfromthe

perichondriumandthemastoidfascia,whichgivesusdirect

exposureoftheconcha(Fig.1).

Transectionoftheexternalear

Weretracttheanteriorflapandmakethefirstincisionthrough

theposteriorwalloftheexternalcartilaginousmeatus,cutting

cartilageandskin.Wethenmakethesecondincisionwidely

through the anterior wallof the canal toprevent auditory

stenosis,sectioningtheexternalauditorymeatuscompletely

(Fig.2).

Dissectionoftheretromandibularspace

Weretract the external ear anteriorly to expose the

retro-mandibular space with the parotid gland (Fig. 3). At this

depthwe advocatebluntdissection.Wealways isolatethe

retromandibularvein,whichweligateandtransect.

Because of the posterior access, the auriculotemporal

nerveandthefrontalbranchofthefacialnerveareprotected

withinthesubstanceoftheanteriorlyretractedflap,lateralto

theretromandibularvein(Fig.4).

Fig.1. Incisionoftheskinandthesofttissuewithdirectviewoftheconcha.

Fig.2. Theincisionoftheanteriorwallofthecanalandtransectionofthe entireexternalauditorycanal.

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Fig.3.Dissectionoftheretromandibularspacewiththeparotidgland.

Fig.4.Theisolatedretromandibularvein.

Fig.5.Exposureofthemandible.

Themandibularskeleton

Wemanipulatethemandibleopenandclosedtofindoutthe

locationofthecondyleandtheramus.Whenthebonysurface

isreached,weinciseandraisethemandibularperiosteumto

isolatethemandibularskeleton(Fig.5).

Closure

Weirrigatethesitewithhydrogenperoxideandany

bleed-ingismeticulouslycontrolled.Weclosetheparotidcapsule

tightly with an absorbable, running, horizontal mattress

suture to avoida salivary fistula. We thenreconstruct the

externalauditorycanalwith3deepholdingsuturestoprevent

stenosis of the externalauditorymeatus. Finally,we close

theskinandsubcutaneoustissuewithinterruptedabsorbable

sutures(Fig.6).

Medication

Wealwaysinsertapetroleumgauzeintheexternalauditory

canal,whichisleftinplacefor10daysandchangedevery

3 days. Weapply acompression dressing for 7 days. We

keepthewoundmoistwithantibioticointmentandhydrogen

peroxideappliedtwiceadayfor1week.Wechecktheear

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Fig.6.Closureoftheaccess.

Results

Themeandurationofoperationwas43min(range29–67).

At1-year follow-upthe mean maximal interincisal mouth

openingwas37.5(SD±3.7)mmandallpatientshadgood

occlusionwithoutdysfunctionalsymptoms;examinationby

conventionalradiographyandcomputedtomographyshowed

acceptableosteosynthesisinallcasesexceptonepatientin

whom fixationfailedbut withasatisfactoryocclusion: no

patientneededtoreturntotheoperatingtheatrefor

adjust-mentbecauseofthemalocclusion.

Theintegrityoftheexternalearwaspreservedinallcases

withnoauditorystenosisoraestheticdeformity.Nopatients

reportedpermanentweakness of the facialnerve or injury

totheauriculotemporalnerve.Temporary weaknessof the

frontalbranchof thefacialnerve wasfoundin1 case, but

functionhadreturnedtonormalafter1.6months.Therewere

nocasesofsalivaryfistula,sialocele,orFreysyndrome,and

noinfections,haematomasorscarring.

Discussion

Manymethodsofaccesstothemandibletechnicalvariants

havebeendescribed,andtheycanbedividedintotwomain

groups:transoralandtransfacial.

Transoral access, also called the mandibular vestibular

approach,5 permits the exposure of the entire mandibular

skeletonfrom the symphysis tothe condyle.This routeis

fastandtechnicallyeasy,andhasthegreatadvantagethatthe

scarishiddenintheoralcavity.Thedisadvantagesarethat

it doesnotpermitsafemanagementof highcondylar

frac-turesorcomminutedfracturesthatinvolvethelowerborder

ofthe mandible,althoughtherecentdevelopmentof

endo-scopic techniques has helped.6 The risks of thisapproach

arethepotentialdamagetothementalisnerveandthe

pos-sibilityof malposition of the lowerlipas a resultof poor

technique when repositioning the mentalis muscle during

closure.7

Thethreemaintransfacialapproachesare:submandibular,

retromandibular,andpreauricular,andtechnicalvariantsand

combinationsofthesehaveresultedindifferentroutestogain

exposureofthemandibularskeleton.

The submandibular access,8 also called the Risdon

approach, is indicated for many procedures. Its two main

disadvantagesarepotentialinjuryofthemarginal

mandibu-larbranchofthefacialnerve,andtheplacementofavisible

scar.Thisroutedoesnotallowaneasyapproachtothe

condy-larandsymphysealregionsofthemandible.Thevariantsof

thisapproachincludeposteriorextensiontowardsthe

mas-toid region, and anteriorly towards the submental region,

withorwithouta“stepped/zigzag”incisionoralip-splitting

approach.Finally, bilateralsubmandibularaccessescanbe

connected at different levels in the neck with a complete

exposureofthemandible.

Retromandibular access permits the exposure of the

ramus, condyle, and coronoid process. The route can be

retroparotid,transparotid,orpreparotid.9,10 Thethreemain

concerns about it are: potential injuryto the facial nerve,

postoperativesalivarycomplicationsrelatedtodamagetothe

parotid,andthevisibilityofthescar.

Preauricularaccessismainlyindicatedforapproachtothe

mandibularcondyle.Theincisioncanbeplacedindifferent

regionsrelatedtothetragus,anditcanbeextendedtowards

thetemporalareaindifferentsitesdependingonthe

preau-ricularhair.Apartfromthepotentialinjurytothefacialnerve

andthepossibilityofavisiblescar,postoperativeconcernis

relatedtothepotentialdevelopmentofFreysyndrome.11,12

These are the three most commonly used routes to

access the mandibular skeleton. The retroauricular

trans-meatal approach can be considered a technical variant of

the preauricular approach, and this method is advocated

for high fractures of the condylar head, but it can be a

difficult approach for fractures of the condylar base.2–4

The facial rhytidectomy approach,13 which allows wide

exposure of the mandibular skeleton, can be considered

tobe associated withthe preauricularand the

retroauricu-lar approach withouta transmeatal route. The classic and

modified Blairincisionsaremade bythe preauricularplus

the retromandibular approaches.14 Finally, the association

between the submandibular, the retromandibular, and the

preauricularorretroauricularapproaches,withorwithouta

transmeatalroute,isusedforwideexposureofthemandible,

(5)

Althoughwecannotdrawanysignificantconclusions,the

retroauriculartransmeatalapproachhasanextremelylowrisk

ofinjurythefacialnerve,andleavesaninvisiblescar.The

morbidityisnegligibleintermsofdamagetothefacialnerve,

vascularinjuries,aestheticdeformity,auditorystenosis,

sali-vary fistulas, sialocele, andFrey syndrome.We thinkthat

furtherprospectiveclinicaltrialsarenecessarytoassessand

eventuallydevelopthisapproach.

Acknowledgement

WeareverygratefultoMartaRissoforthebeautiful

illustra-tionsoftheretroauriculartransmeatalapproach.

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