Laparoscopic Myotomy.docx

Laparoscopic Myotomy.docx

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LaparoscopicMyotomy

AnnSurg.2006May;243（5）:

587–593.

LaparoscopicMyotomyforAchalasia:

PredictorsofSuccessfulOutcomeAfter200Cases

AlfonsoTorquati,MD,MSCI,WilliamO.Richards,MD,MichaelD.Holzman,MD,MPH,andKennethW.Sharp,MD

FromtheDepartmentofSurgery,VanderbiltUniversityMedicalCenter,Nashville,TN.

Objective:

Laparoscopicmyotomyisthepreferredtreatmentofachalasia.Ourobjectivesweretoassessthelong-termoutcomeofesophagealmyotomyandtoidentifypreoperativefactorsinfluencingtheoutcome.

Methods:

Preoperativeandlong-termoutcomedatawerecollectedfrompatientsundergoinglaparoscopicmyotomyforachalasiaatourinstitution.Theprimaryendpointofthestudywasthepostoperativechange（delta）indysphagiascore.Thisscorewascalculatedbycombiningthefrequencyandtheseverityofdysphagia.Persistentpostoperativedysphagiawasdefinedas1standarddeviationlessthanthemeandeltascoreofallpatients.Logisticregressionwasusedtoidentifyindependentpreoperativefactorsassociatedwithsuccessfulmyotomy.

Results:

Atotalof200consecutivepatientswereincludedinthestudy.Atameanfollow-upof42.1months,themeandeltadysphagiascorewas7.1±2.6;therefore,themyotomywasconsideredsuccessfulwhenthedeltascorewas>4.5.Accordingtothisdefinition,170（85%）patientsachievedexcellentdysphagiarelief（responders）.Respondershadhigherpreoperativelowesophagealsphincter（LES）pressurethannonresponders:

42.6±13.1versus23.8±7.0mmHg（P=0.001）.HighpreoperativeLESpressureremainedanindependentpredictorofexcellentresponseinthemultivariatelogisticregressionmodel.PatientswithLESpressure>35mmHghadanoddsratioof21.3,makingmorelikelytoachieveexcellentdysphagiareliefaftermyotomycomparedwiththosewithLESpressure≤35mmHg（oddsratio,21.3;95%confidenceinterval,6.1–73.5,P=0.0001）.

Conclusion:

Laparoscopicmyotomycandurablyrelievesymptomsofdysphagia.ElevatedpreoperativeLESpressurerepresentsthestrongestpositiveoutcomepredictor.

InNorthAmerica,esophagealachalasiaisarareidiopathicmotilitydisorderthataffects1in100,000individuals;yetitisthemostcommonlydiagnosedprimaryesophagealmotilitydisorder,andsecondonlytogastroesophagealrefluxdisease（GERD）asthemostcommonfunctionalesophagealdisorder.1Thewidespreadavailabilityofpneumaticdilation,botulinumtoxininjectionsandminimallyinvasivesurgicaltechniquesformyotomyhasresultedincontentioustherapeuticstrategies.Ingeneral,alltreatmentsarefocusedonthereductionofloweresophagealsphincter（LES）restingpressure,resultinginimprovedesophagealemptyingandsymptomaticreliefofdysphagia.Whilepartiallyandfortheshort-termresponsivetoendoscopicdilatationorbotulinumtoxininjections,mostpatientswithachalasiaeventuallyrequireoperativemanagementbecauseonlysurgicaltreatmenthasbeenproventoprovidelong-termreliefofdysphagia.2

Surgicaltreatmentofachalasiahasevolveddramaticallyoverthepast13years.SincethefirstreportoflaparoscopicHellermyotomyin1991byCuschieri3andthoracoscopicHellermyotomybyPellegrini4in1992,minimallyinvasivesurgeryhasbecamethegoldstandardforthetreatmentofachalasia.Morerecently,thelaparoscopicmanagementofesophagealachalasiahasachievedwidespreadacceptanceandisnowthefirstlineoftherapyforpatientswithachalasia.2Thesatisfactoryshort-termresultsofthisprocedurearewelldocumentedinseverallargeseries.5–11Inthesestudies,persistentpostoperativedysphagiawasobservedin10%to30%ofthepatients,andlittleisknownaboutthepreoperativefactorsthatmaypredictlong-termresolutionofdysphagiaafterlaparoscopicesophagealmyotomy.Therefore,theaimofthisstudywastoidentifypreoperativepatientcharacteristics,includingmanometricandclinicalfindings,thatpredictlong-termsuccessfuloutcomeafterlaparoscopicesophagealmyotomy.

Patients

Thestudy,followingInstitutionalReviewBoard（IRB）approval,wasconductedatVanderbiltUniversityMedicalCenterinNashville,Tennessee.Preoperativedata,includingastructureddysphagiascore,wereprospectivelycollectedonpatientsundergoinglaparoscopicmyotomyforachalasiaatourinstitution.12Allpatientsunderwentpreoperativemanometry.Patientsweretestedwhileoffallantisecretoryorpromotilitymedications.Standardesophagealmanometrywasperformedusinga6-channelsolid-stateprobe（SandhillScientific,HighlandsRanch,CO）withapull-throughtechnique.TheLESpressurewasdefinedasthedifferencebetweentheendexpiratorygastricbaselinepressureandthemiddleend-expiratorypressurejustdistaltotherespiratoryinversionpoint.ClinicaldiagnosisofachalasiawasconfirmedmanometricallybythepresenceofsimultaneousesophagealbodycontractionsandanonrelaxingLES.Inthefewpatientswhounderwentpreoperativemanometryoutsideofourfacility,manometricdatawerereanalyzed.

Allthepatients（n=224）enteredinourachalasiadatabasefrom1994to2004weremailedafollow-upstructureddysphagiascorequestionnaireoraskedtocompleteoneduringafollow-upvisit.Thepatientswhodidnotreturnthequestionnaireswereallowedtoanswerthesurveyoverthephone.Attheend,24patientswereexcludedfromthestudybecausewewereunabletoobtainapostoperativedysphagiascorefromthem.

SurgicalTechnique

OurtechniqueforlaparoscopicHellermyotomyhasbeenpreviouslydescribedindetail.10Briefly,afterthephrenoesophagealligamentisdividedandthefatpadexcisedexposingtheanteriorgastroesophagealjunction,themyotomyisperformedbyincisingthedistal4to6cmofesophagealmusculature.Themyotomyisextended1to2cmontothegastriccardiausingcauteryscissorsoranultrasonicscalpel.Intraoperativeendoscopyisperformedsimultaneouslytoassesstheadequacyofthemyotomy,togaugehowfartocarrythemyotomyontothegastriccardia,andtodetectmucosalperforations.WeaddedaDoranteriorhemifundoplicationinselectedpatientsearlyinourexperience,thosehavingintraoperativeperforation,andmoreroutinelyinourmostrecentexperience.Inourearlyexperience,weroutinelyperformedacontrastswallowonpostoperativedayoneinallpatientstoruleoutanoccultleak.Wecurrentlydoitselectivelyforpatientswhohadintraoperativeperforation,andthosewhohavepostoperativechestpain,tachycardia,orfever.Forpatientsnotrequiringswallowstudy,andthosewithanegativeone,aclearliquiddietisstartedthemorningaftersurgery,andpatientsaredischargedlaterthatday.

OutcomeMeasures

Theprimaryend-pointwaspostoperativechange（delta）indysphagiascore.12Thescore（range0–10）wascalculatedbycombiningthefrequencyofdysphagia（0=never,1=<1day/wk,2=1day/wk,3=2–3days/wk,4=4–6days/wk,5=daily）withtheseverity（0=none,1=verymild,2=mild,3=moderate,4=moderatelysevere,5=severe）.Thecutoffpointusedtodichotomizetheoutcomeafterlaparoscopicesophagealmyotomywasselectedatonestandarddeviationbelowthemeandeltascoreoftheentirecohort.Patientwithdeltadysphagiascorefallingbelowthecutoffpointwereconsideredwithunsuccessfuloutcomegroup.Patientswhounderwentendoscopicdilationand/orredomyotomy,aftertheinitialmyotomy,werealsoclassifiedintothisgroup.

StatisticalAnalysis

Thedataarepresentedasmean±SDforcontinuousvariables,andascountsorproportions（%）forcategoricalvariables.Correlationswereanalyzedbyunivariateregressionanalysis（Pearson）andSpearmancorrelationcoefficients.

Binarylogisticregressionanalysiswasusedinbothunivariateandmultivariatemodelingtoidentifyindependentpreoperativevariablesassociatedwithlong-termreliefofdysphagiaafterHellermyotomy.Independentvariablesexaminedincluded6putativepreoperativefactors:

age,gender,LESpressure,historyofendoscopicdilation,historyofbotulinumtoxininjection,andASAclass.Thefollowingmodel-buildingstrategywasused.Univariateanalysisusinglogisticregressionwasappliedtoidentifysignificantassociationswiththedependentvariable（surgicaloutcome）.Transformedanduntransformeddatawereusedintheanalysis.AllindependentvariableswithassociationsofP≤0.1thenunderwentmultivariateanalysisbysimplyenteringthemtogetherusingthebackwardstepwisemethod.Thefollowingcutoffpointswereusedforthebinarylogisticregressionstepwisemethods:

P=0.05forentryintothemodelandP=0.10forremovalfromthemodel.The“best”modelforeachcasedefinitionwasbasedonthestrengthofthemodel（HosmerandLemeshowgoodness-of-fittest）,itsclinicalutility,andthebiologicplausibilityofthemodel.Allcontinuousvariablesincludedinthefinalmodelwerethencategorizedtoimproveeaseofuse.Modelparameterswereestimatedbythemaximum-likelihoodmethod.Fromtheseestimates,oddsratios（OR）with95%confidenceintervals（CI）werecomputed.

TheSPSSstatisticalsoftwareprogram（version13.0,SPSS,Chicago,IL）wasusedforallanalyses.StatisticalsignificancewassetatP<0.05.

RESULTS

Follow-updysphagiascoreswereavailablefrom200patients（93females）whounderwentlaparoscopicmyotomyatVanderbiltUniversityMedicalCenter.Patientagesrangedfrom13to80years（49.5±1.5years）.Themedianhospitalstaywas1day（range,1–3days）Therewere12intraoperativeperforations:

6inthefirst50proceduresand6inthelast150.Alltheesophagealperforationswereidentifiedandrepairedatthetimeofsurgeryandpatientshadnosequelae.Fourconversionstoanopenprocedureoccurredwithinthefirst50patients;therewe