AccuracyandcomplicationsassociatedwithfreehandC1lateralmassscrewfixationtechnique:aradio

• 作 者: YongHu zhenshanYuan WeixinDong RongmingXu
• 机 构: 宁波市第六医院
• 出 处: 中华医学会第十七届骨科学术会议暨第十届COA国际学术大会
• 发表日期: 2015年4期
• 关键词: C1lateralmassscrew Complications Atlas computedtomography

　　Study Design.Aretrospectiveradiographic andclinicalstudyofthetechniqueforfreehandC1lateralmassscrew(C1LMS)fixation. Objective.TheaimsofthisstudyweretoevaluatealargeseriesofposteriorC1LMStodetermineaccuracybased oncomputedtomography(CT)scanandassessperioperativecomplicationraterelatedtoerrantscrew placement. Summary of Background Data.C1lateralmassfixationtechniqueisfrequentlyperformedforuppercervical instability.TheuniqueandvariableC1anatomycanmakeinstrumentationatthislevelchallengingandproneto potentiallysevere,evenlife-threateningcomplicationssuchasvertebralarteryorneurologicinjury. Methods.ClinicaldatawereobtainedfromthemedicalrecordbetweenJanuary2003andDecember2011. AccuracyofscrewplacementwasevaluatedonpostoperativereconstructiveCTscanof196patientswith atlantoaxialinstability.RadiographicanalysisincludedmeasurementofpreoperativeandpostoperativeCTscans toevaluaterelevantanatomyandclassifyaccuracyofinstrumentationplacement.Screwsweregradedusingthe followingdefinitions:TypeI,screwthreadscompletelywithinthebone("ideal");TypeⅡ,lessthanhalfthe diameterofthescrewviolatesthesurroundingcortex("safe");andTypeⅢ,clearviolationoftransverse foramenorspinalcanal("unacceptable"). Results.Onehundredninety-sixcases(107malesand89females)underwentposteriorC1LMSfixation.Two caseshadunilateralC1fixationappliedbecauseofspecificpathologyoranatomicconstraints.Atotalof390 C1LMSwereplacedbut32screws(8.2%)wereexcludedfromaccuracymeasurementsbecauseoflackof postoperativeCTscans;thesepatientswerestillincludedintheassessmentofpotentialclinicalcomplications basedonclinicalrecords.Ofthe358screwswithpostoperativeCTimaging,85.5%ofscrews(TypeI)wererated asbeingintheidealposition,11.7%ofscrews(TypeⅡ)wereratedasoccupyinga"safe"position,andten screws(2.8%)were"unacceptable"(TypeⅢ).Overall,97.2%ofscrewswereratedTypeIorⅡ.Ofthe10screws thatwereunacceptableonpostoperativeCTimaging,therewerenoknownassociatedneurologicorvertebral arteryinjuries.Sevenunacceptablescrewserredmediallyintothespinalcanalandtwopatientsunderwent revisionsurgeryformedialscrews.In2patients,unilateralC1lateralmassscrewspenetratedtheC1anterior cortexbyapproximately4mm.NeitherpatientwithanteriorC1penetrationhadevidenceofinternalcarotid arteryorhypoglossalnerveinjury.CTscanshowedpartialentryofC1LMSintothevertebralarteryforamenofC1 intencases,Noocclusion,associatedaneurysmorfistulaoftheVAwasfound.Twopatientscomplainedof postoperativeoccipitalneuralgia.Thiswastransientinonepatientandresolvedbytwomonthsaftersurgery.The secondpatientdevelopedpersistentneuralgiawhichremained2yearsaftersurgery,necessitatingpainservice referral.Forpatientswhounderwentisolatedatlantoaxialstabilization,theoperativetimewas100minutes± standarddeviationof30minutes(range60-150minutes),andaveragebloodlosswas450ml±standard deviation80ml(range300-1200ml). Conclusion.ThetechniqueforfreehandC1lateralmassscrewfixationappearstobesafeandeffectivewithout intraoperativefluoroscopyguidance.Preoperativeplanninganddeterminationoftheidealscrewinsertionpoint, theidealtrajectory,andscrewlengtharethemostimportantconsiderations.Inaddition,fewermal-positioned screwswereinsertedasthecaseseriesprogressed,suggestingalearningcurvetothetechnique.C1lateralmass screwscanbeimplantedwiththehelpoffluoroscopyorspinalnavigationsystemsnavigationguidanceforcomplicatedcasesorbysurgeonswithoutexperienceinthistechnique.