球囊輔助復(fù)位在高能量爆裂骨折中的應(yīng)用

Balloon-AssistedFractureReductioninHigh-EnergyBurstFractures球囊輔助復(fù)位在高能量爆裂骨折中的應(yīng)用

DalipPelinkovic,MD,*RanjithKamalUdayakumar,MD,?andFrankM.Phillips,MD*

Thecombinationofpercutaneusvertebralaugmentationwithposteriorinstrumentationmaybeanattractivetreatmentoptionforcertainhighenergyburstfractures.Biomaterialssuchascalciumphosphatecementarebiocompatible,sharesimilarbiomechanicalprop?ertiestobone,andaregraduallyreplacedbyhostbonetissue.Earlybiomechanicalandclinicalresultsindicatethattheanteriorcolumnmayberestoredwithouttheneedofatraditionalanteriorsurgicalapproach.Furtherclinicalstudiesareneededtocon?rmthatthislessinvasiveapproachimprovespatientoutcome.SeminSpineSurg22:67-72?2010ElsevierInc.Allrightsreserved.

對(duì)于某些高能量爆裂骨折而言，經(jīng)皮椎體增強(qiáng)聯(lián)合后路器械固定是一個(gè)很有吸引力選擇。有些生物材料，如磷酸鈣骨水泥，具有良好的生物相容性，與骨的生物力學(xué)特性相似，可以逐漸被宿主骨替代。早期生物力學(xué)和臨床結(jié)果顯示，前柱獲得了恢復(fù)，不需要再進(jìn)行傳統(tǒng)的前路手術(shù)。還需要更多的臨床研究來證實(shí)這種微創(chuàng)方法對(duì)患者結(jié)果的促進(jìn)作用。KEYWORDSburstfracture,percutaneus,balloon-assisted,reduction

關(guān)鍵詞：爆裂骨折，經(jīng)皮，球囊輔助，復(fù)位。

high-energythoracolumbarburstfracturescanbetreatedwithdecompressionandanterior,posterior,orcircum?ferentialfusion.Traditionally,reconstructionoftheposteriortensionbandwitharodhookorrodscrewconstructisap?pliedtoassistinprovidingstabilityandreestablishingthesagittalbalance.Ligamentotaxismayalsoassistinreducingthevertebra.Despiteexcellentinitialfracturereduction,in?adequateanteriorcolumnsupportmayleadtolossofreduc?tion,poorlong-term?xation,orevenfailureoftreatmentovertime.1-3Insuf?ciencyoftheanteriorcolumniscausedbyboththevertebralbodyfractureandalsomigrationofthedisktissuethroughtheendplateintothefracturedvertebralbody,whichmaynotberestoredwithindirectreductionthroughposteriorinstrumentation.4Moreextensiveanteriorprocedures,suchasanteriorinstrumentationandstrutgraft?ing,orcageimplantationmaysuccessfullyrestoretheante?riorspinalcolumnsupportandareproventobeeffectiveandsparemotionsegments.5,6However,anteriorproceduresaremoreinvasiveandareassociatedwithincreasedhospitaliza?tion,bloodloss,increasedsurgicalmorbidity,orevenmor?tality.5

高能量胸腰椎爆裂骨折常采用減壓，前路、后路或環(huán)形融合進(jìn)行治療。傳統(tǒng)后側(cè)張力帶結(jié)構(gòu)常采用鉤棒或釘棒結(jié)構(gòu)來提供穩(wěn)定和重建矢狀面平衡。韌帶整復(fù)術(shù)有助于復(fù)位椎體。盡管早期復(fù)位非常好，如果前柱支持不足，可能導(dǎo)致復(fù)位丟失、內(nèi)固定失效、甚至治療失敗。前柱缺損可由于椎體骨折和椎間盤組織經(jīng)終板嵌入骨折椎體引起，而這是無法通過后路器械進(jìn)行間接復(fù)位的。通過更廣泛的前路手術(shù)進(jìn)行器械固定支撐、cage植入等方法可以有效恢復(fù)前柱支撐，減少節(jié)段活動(dòng)。但是前路手術(shù)的創(chuàng)傷較大，且住院時(shí)間更長，出血更多，增加了外科手術(shù)率，甚至病死率。Recently,percutaneousinstrumentationcombinedwithpercutaneousvertebralbodyaugmentation(kyphoplasty/vertebroplasty)hasbeenaddedtothesurgicalarmamentar?ium.Inosteoporoticvertebralfractures,kyphoplastyhasproventobeasafeprocedurewithexcellentoutcomes.7However,thepathoanatomyofahigh-energyburstfractureisdistinctfromosteoporoticvertebralfractures.Threefrac?turepatterns-wedge,crush,andbiconcave-havebeende?scribedintheosteoporoticpatient.8,9Theposteriorwallandendplatesaremostlyintact.Inaddition,theosteoporoticbonewithdecreasednumberandconnectivityoftrabeculaeallowsrestorationofthevertebralheightasballoontampin?ationcompressesthesoftcancellousboneandelevatestheendplates.7,10近來，經(jīng)皮器械和經(jīng)皮椎體增強(qiáng)技術(shù)（后凸成形和椎體成形術(shù)）已成為外科手段。對(duì)于骨質(zhì)疏松性骨折，后凸成形術(shù)已被證實(shí)是十分安全有效的。然而高能量爆裂骨折與骨質(zhì)疏松性骨折的病理解剖是不同的。骨質(zhì)疏松性骨折有三種骨折形式：楔形、爆裂、雙凹，后壁和終板多數(shù)是完整的。而且，骨質(zhì)疏松的骨骼由于骨小梁減少，連接力降低，當(dāng)球囊擴(kuò)張時(shí)，可擠壓松軟的松質(zhì)骨，抬高終板，從而恢復(fù)椎體高度。

Incontrast,high-energytraumaticburstfracturesareusu?allycausedbysubstantialaxialloading,whichresultsincom?pressionfailureofatleastthemiddleandanteriorspinalcolumn.Thesuddenaxialloadresultsinavertebralendplatefailureasadjacentdisktissueisdrivenintothevertebralbody.Thevastmajorityofburstfracturescausesomecanalcompromise,typicallybecauseofosseousfragmentsfromthesuperiorendplate.Determinantsofinstabilityareprogressiveneurologicalde?cit,progressivekyphosis,radiographicevi?denceofsubstantialposteriorcolumninstability,greaterthan50%lossofvertebralbodyheightinassociationwithkypho?sis.Fracturedanddepressedendplatesincreasethechanceofdiskdisplacementintothevertebralbodywithsubsequentfocalspinaldeformityandfailureofthetreatment.Conse?quently,thecombinationofindirectreductionofthoraco?lumbarburstfractureswithballoon-assistedendplatere?ductionmayrecreateastableanteriorcolumn,andstableendplateswithlong-termmaintenanceofthesagittalalignment(Fig.1).Advantagesofminimalinvasivetech?niquesarequickerrecovery,lesspain,decreasedsurgicalmorbidity,andpotentiallyamorestableconstructthanisolatedposteriororanteriorstabilizationbecauseoflesstissuedisruption.

相反，高能量爆裂骨折通常由巨大的軸向負(fù)荷引起，至少可使前柱和中柱的壓縮破壞。突然的軸向負(fù)荷可破壞椎體終板，使鄰近的椎間盤組織疝入椎體。大多數(shù)爆裂骨折可引起椎管侵害，骨塊特別常來自上終板。進(jìn)行性神經(jīng)損害、進(jìn)行性后凸、放射學(xué)證實(shí)的后柱不穩(wěn)、椎體高度喪失大于50%伴有后凸者被認(rèn)為是不穩(wěn)定。骨折和凹陷的終板增加了椎間盤疝入椎體、局部畸形、治療失敗的機(jī)會(huì)。這樣一來，對(duì)胸腰椎爆裂骨折通過間接復(fù)位輔以球囊擴(kuò)張使終板復(fù)位就可以重建前柱和終板的穩(wěn)定，從而保持矢狀序列的長期穩(wěn)定。微創(chuàng)的優(yōu)勢在于恢復(fù)快、疼痛輕、減少了外科手術(shù)率、由于對(duì)組織破壞少，可能更穩(wěn)定。Transpedicularvertebralcancellousbonegraftingforthetreatmentofvertebralcompressionfractureshasbeende?scribedinthepublisheddatawithlittlesuccessinmaintain?ingtheanteriorcolumnofthespineandwasassociatedwithahighfailurerate.11-15Transpedicularhydroxyapatitestickgraftingisanothertechnique,whichiscurrentlyunderinves?tigation.16經(jīng)椎弓根植骨治療椎體壓縮骨折，文獻(xiàn)報(bào)道難以維持前柱，并有很高的失敗率。近來導(dǎo)航下經(jīng)椎弓根羥基磷灰石棒植入是另一項(xiàng)技術(shù)。BasicScienceStudies

Mermelsteinetal17showedintheircadavericburstfracturestudythatvertebroplastywithcalciumphosphatecement(CPC)reinforcedtheanteriorcolumnandreducedthestressonthepedicle-screwrodconstruct.Inanothercadavericstudy18balloon-assistedendplatereductionwasusedtosig?ni?cantlyrestorevertebralheightandendplateanatomyaf?tershortsegmentalinstrumentation.Afollow-upstudybythesamegroupusedadetailed3-dimensionalradiographyatdifferentphasesofthemodel,fromfracturetoballoon-as?sistedendplatereductionandcementinjection.Theydem?onstratednocollapseafterremovaloftheballoons,mainte?nanceofthevertebralheightwithcementinjection,andnocementextravasation.18

Anotherstudyinvestigatedtheroleofthelongitudinallig?amentsduringballoon-assistedendplatereductioninthora?columbarburstfractures.19Inahumancadavericburstfrac?turemodel,theanteriorandposteriorbonedisplacementwasassessedafterapplyingshortsegmental?xationfollowedbykyphoplasty.Althoughanteriorboneandposteriorbonedisplacementoccurredwiththein?ationoftheballoons,theeffectsubsidedafterde?ationanddidnotrecurwithinjec?tionofthecement.Theamountofdisplacement(?1mm)wasthoughttobeoflittleclinicalsigni?cance.Accordingtothisstudy,anintactposteriorlongitudinalligamentdoesnotappeartobenecessarytopreventposteriorbonedisplace?ment.Theycouldalsonotcon?rmtheimportanceoftheposteriorlongitudinalligamentwithreductionthroughliga?mentotaxis.基礎(chǔ)研究

Mermelstein等研究發(fā)現(xiàn)，磷酸鈣骨水泥可以強(qiáng)化爆裂骨折的前柱，減少椎弓根釘?shù)牡膲毫?。在另一?xiàng)尸體研究中，采用球囊復(fù)位終板，短節(jié)段固定，使椎體高度和終板解剖顯著恢復(fù)，該研究采用三維X線對(duì)從骨折－球囊擴(kuò)張終板復(fù)位－骨水泥注入的不同階段進(jìn)行詳細(xì)觀測，他們發(fā)現(xiàn)球囊取出后椎體不會(huì)塌陷，骨水泥注入后椎體高度得以保持，沒有骨水泥滲漏。另一項(xiàng)研究調(diào)查了后縱韌帶在胸腰椎爆裂骨折球囊輔助終板復(fù)位中的作用。在一個(gè)人類尸體爆裂骨折模型中，采用短節(jié)段固定輔以后凸成形，評(píng)估前后骨塊移位。雖然球囊擴(kuò)張時(shí)前后骨塊發(fā)生移位，但球囊收縮時(shí)，這種作用就減小了，且椎體內(nèi)注入骨水泥后，也沒有再發(fā)生。其移位的程度（＜1mm）沒有臨床意義。根據(jù)這項(xiàng)研究，完整的后縱韌帶無法阻止后方骨塊的移位。他們也無法確定韌帶復(fù)位技術(shù)中后縱韌帶的重要性。ClinicalStudies

Afzaletalreportedon16patients(age,22-53years)withhigh-energyburstfractures(12DenistypeBand4DenistypeCburstfractures)whowerefollowedupfor1monthclini?callyandradiographically.20Patientswithposteriorlongitu?dinalligamentinjurywereexcluded.Aftershortsegmentpediclescrew?xation,aballoon-assistedkyphoplastywasperformedwithCPC.Inaddition,aremovableplasticjacketwasprescribedfor8weeks.Cementleakagewasobservedin3patients(2inthespinalcanal,1inthediskspace),withnoclinicalconsequences.Noposteriorwalldisplacementwasrecorded.Theaveragekyphosisangleofthesegmentwasreducedby10°.臨床研究

Afzal等報(bào)道了16例（年齡，22－53歲）高能量爆裂骨折病例（12例DenisB型,4例DenisC型爆裂骨折），臨床與X線進(jìn)行隨訪1個(gè)月。后縱韌帶損傷者排除在外。短節(jié)段椎弓根釘固定后，采用CPC進(jìn)行球囊輔助后凸成形術(shù)?？刹鹗剿芰蠆A克固定8周。3例患者發(fā)生骨水泥滲漏（2例在椎管，1例在椎間隙），沒有臨床癥狀。沒有發(fā)生后壁移位，平均后凸角減少10°。

Anotherinvestigationincluded18patients(64?15years)withseverethoracolumbarburstandcompressionfractures(Figs.2-4).21Allpatientsweretreatedwithshortsegmentpercutaneousposteriorinstrumentationandbal?loonkyphoplastywithCPCwithin24hoursofinjuryandwerefollowedupfor22months.Kyphosisimprovedfromanaverageof16°-2°.Cementleakagewasobservedonlyante?riortothevertebralbodywithoutclinicalsequelae.Asecondstudybythesamegrouptreatingthoracolumbarburstfrac?tureswithcalciumphosphateandanopenapproachforpos?teriorspinalinstrumentationshowedsimilarlyencouragingresultsat24monthswithoutmajorcomplications(Fig.1).22另一項(xiàng)研究有18例病人（64±15歲），嚴(yán)重的胸腰椎爆裂和壓縮骨折（圖2－4）。所有的病人都在傷后24小時(shí)內(nèi)采用后路經(jīng)皮短節(jié)段固定CPC球囊后凸成形術(shù)，隨訪22個(gè)月。后凸從平均16°恢復(fù)至2°。骨水泥僅滲漏至椎體前方，沒有后遺癥。同一小組采用羥基磷灰石和開放后路固定取得了相似的效果，隨訪24個(gè)月，沒有嚴(yán)重并發(fā)癥發(fā)生（圖1）。AprospectivecaseseriesonstandalonekyphoplastywithCPCinMagerltypeAfractureswithoutde?citnotedadecreaseofpainonthevisualanaloguescalefrom8.7preoperativelyto3.1postoperativelyin7days,and1atthelastfollow-upat30months.23TheRolandMorrisDisabilityscoredemonstratedasimilardecreaseintheearlypostoper?ativetimeperiod.Twoanteriorwallperforationsbycannulasduringtheprocedure,and6cementleakageswereobservedonpostoperativecomputedtomography(CT)scans(5casesintothediskspace,1casewithsmallleakageinthelateralportionofthespinalcanal).Allwerewithoutneurologicalorvascularconsequences.Also,nolong-termcomplicationswereobservedatthelast30monthfollowup.Twentyper?centcementresorptionandsubstitutionwasnotedonCTscansat1yearpostoperatively.Lossofcorrectionwas9°(0°-17°)fromimmediatepostoperativelytothelastfol?low-upat30months.Thismayrelatetolossofvertebralheightastheresorbablecementisremodeled.

一項(xiàng)單獨(dú)采用CPC后凸成形治療沒有神經(jīng)損害的MagerlA型骨折的病例回顧中，術(shù)后7天疼痛視覺模糊評(píng)分從術(shù)前8.7分恢復(fù)至3.1分，術(shù)后30個(gè)月恢復(fù)至1分。RolandMorris殘疾評(píng)分在術(shù)后早期也相應(yīng)下降。兩例前壁穿孔，6例術(shù)后CT發(fā)生骨水泥滲漏入椎間隙，1例少量滲漏至椎管側(cè)方。所有病人沒有出現(xiàn)神經(jīng)或血管并發(fā)癥。30個(gè)月隨訪沒有長期并發(fā)癥。20%在術(shù)后1年CT觀察時(shí)骨水泥吸收替代，從術(shù)后即時(shí)至術(shù)后30個(gè)月的矯正丟失為9°（0°－17°），這可能與可吸收骨水泥吸收后引起的高度丟失有關(guān)。

FillerChoice

Considerationsformaterialsforvertebralaugmentationforhigh-energythoracolumbarburstfracturesaredifferentfromthoseinosteoporoticfractures.Thecementshouldbeinject?ablethroughcannulas,easyhandling,appropriatelyviscous,haveanadequateworkingtime(15min),lowcuringtemper?ature,adaptingandlastingmechanicalproperties,highra?dioopacity,biocompatibility,bioactivity,andslowbiodegra?dation.Theoptimalmechanicalpropertieshavenotyetbeendeterminedforhigh-energyburstfractures.Stiffnessandyieldstrengthshouldbesimilarthehostbone.Presently,polymethylmethacrylate(PMMA)cementismostwidelyusedforvertebralaugmentationprocedures,withanexten?sivehistoryofinvitroandinvivouse.Itcureswithanexothermicreaction,whichmightbedesirableinpainfulosteoporoticvertebralfractures,butwhichmightbedetri?mentaltothehealingpotentialofhigh-energyvertebralfrac?tures.PMMAisnondegradableandissigni?cantlystrongerincompressionthanthehostbone.24-26

充填物的選擇

高能量胸腰椎爆裂骨折椎體增強(qiáng)材料與骨質(zhì)疏松骨折是不同的。水泥必須可以通過管道注入，易于處理，適當(dāng)?shù)恼吵硇?，有足夠的工作時(shí)間（15min），較低的固化溫度，適當(dāng)和持續(xù)的力學(xué)性質(zhì)，不透X線，生物相容性，生物活性，和低降解性等。對(duì)于高能量爆裂骨折的最合適力學(xué)性質(zhì)還沒有定論。硬度和強(qiáng)度應(yīng)該與宿主骨相似。目前，聚甲基丙烯酸甲酯（PMMA）水泥廣泛用于椎體強(qiáng)化，在體內(nèi)體外均有較長的應(yīng)用史。固化過程會(huì)產(chǎn)生發(fā)熱反應(yīng)，這對(duì)疼痛性骨質(zhì)疏松性骨折是合適的，但對(duì)高能量椎體骨折可能會(huì)損傷其愈合潛力。PMMA無法降解，且在壓力強(qiáng)度上遠(yuǎn)高于宿主骨。Incontrast,theimmediatemechanicalpropertiesofCPCareclosertobone;however,themechanicalpropertiesdur?ingtheresorptivephaseareimportantaswell.Thereissomeevidencethatboneformedunderthein?uenceofCPChassimilarmechanicalpropertiestonativehostboneduringitsresorptivephase.26,27InmoststudiesCPChasbeenused.Itconsistsof61%alphatricalciumphosphate,26%calcium-hydrogeno-phosphate,and3%hydroxylapatite.

相對(duì)而言，CPC的力學(xué)特性更接近于骨，但在吸收階段的力學(xué)特性也是很重要的。有證據(jù)表明，在CPC吸收期間形成的骨與自然宿主骨有相似的力學(xué)特性。CPC已用于大多數(shù)研究中。其由61%的α磷酸三鈣、26%磷酸氫鈣、3%5。

ThisalphatricalciumcementismarketedasCalcibon(Bi?omet,Merck,Wehrheim,Germany).Mixedwithliquid-to?powderratioof0.35,apasteisobtainedwithacohesiontimeof1minute,aninitialsettingtimeof3minutes,anda?nalsettingtimeof7.5minutesat37°Cwithoutanexothermicreaction.Acompressivestrengthof60Mpaisobtainedat3days.26,28Anosteoconductivepotentialafter6monthswith?outcellulartoxicitywasshowninananimalmodel.26,29-31However,CPCsareinherentlybrittlewithinferiortensilepropertiescomparedwithPMMA.Furtherbiomechanicalstudiesundercyclingloadingareneeded,especiallywhenCPCisusedwithoutposterior?xation.這種α三鈣水泥的商品名為Calcibon(Bi?omet,Merck,Wehrheim,Germany),其液體與粉的比率為0.35，混合1分鐘后變?yōu)楹隣?，?7℃條件下，初始固化時(shí)間為3分鐘，最終固化時(shí)間為7.5分鐘，不產(chǎn)熱。3天壓強(qiáng)達(dá)到60Mpa。在動(dòng)物模型中，6個(gè)月后誘導(dǎo)骨形成，沒有細(xì)胞毒作用。然而，CPC的本身較脆，其抗張性低于PMMA。還要做更多循環(huán)負(fù)荷下的生物力學(xué)研究，特別是CPC單獨(dú)應(yīng)用沒有后側(cè)固定的情況下。Anotherimportantconsiderationistheinteractionofthecementwiththeintervertebraldisktissue.Becausewewouldnotonlyexpectdirectcontactofcementwithhostbone,butalsowiththeintervertebraldisktissue,itseffectsonthevia?bilityofthediskbecomeimportant.32另一個(gè)要考慮的重要問題是水泥與椎間盤組織的反應(yīng)。我們要想到水泥不僅與宿主骨直接接觸，而且與椎間盤組織接觸，其對(duì)椎間盤活力的影響變得十分重要。Indications

Mostreportsofkyphoplastywithposterior?xationhavebeendescribedafteratypeA3injurywithintactposteriorlongitudinalligament.Oneretal33analyzedcomplicationsofcommontreatmentschemesofthoracolumbarfractures.Heconcludesthatsomeofthecomplicationscanbepredictedwithmagneticresonanceimaging.Inthecaseofnonopera?tivelytreatedlow-gradethoracolumbarfracturespatients’ageandanteriorcolumnsinvolvementappearedtobepredictiveofsubsequentincreaseofthekyphoticangleaswellasper?sistentpain.Themostcommonmechanismofkyphosisin?creasewasthroughaprogressivesettlingofthediskintothefracturedendplateandvertebralbody.Intheoperativegroupahighdegreeofendplatecomminution(especiallyofthecentralendplate),theamountofkyphosisreductionandin?volvementoftheposteriorlongitudinalligamentcomplexwaspredictiveofkyphosisrecurrence.However,theyfoundnosigni?cantcorrelationbetweenpainandradiographic?ndings.適應(yīng)癥

后凸成形結(jié)合后側(cè)固定大多數(shù)報(bào)道用于后縱韌帶完整的A3型骨折。Oner等分析了一般胸腰椎骨折治療方案的并發(fā)癥，他推斷有些并發(fā)癥可通過MRI預(yù)見。對(duì)于一個(gè)胸腰椎骨折年紀(jì)較輕、前柱受累的非手術(shù)治療患者，持續(xù)的疼痛意味著后凸角可能增大。大多數(shù)后凸角增大的機(jī)制在于椎間盤組織進(jìn)行性疝入骨折的終板和椎體中。對(duì)于手術(shù)的患者，粉碎的終板(特別是中央終板)、后凸的角度、及后縱韌帶復(fù)合體是否受累等可以推斷后凸畸形是否再發(fā)生。但他們發(fā)現(xiàn)疼痛與放射異常之間沒有顯著的相關(guān)性。Infact,traditionalshortsegmentposterior?xationispronetoanteriorspinalcolumnfailure.Krameretal2fol?lowedup11patientstreatedwithshortsegmentalinstru?mentationandposterolateralfusion.Duringthe2-yearfol?low-upperiod,thekyphosisangleincreasedby12.9°andtheconstructfailedin4of11patients.Furthermore,themain?tenanceoffracturereductionwasmostpredictiveofpatients’outcomeparameters.實(shí)際上，傳統(tǒng)的后側(cè)短節(jié)段固定易于出現(xiàn)前柱衰竭，Kramer等隨訪了11例短節(jié)段固定后外側(cè)融合的患者，隨訪2年，后凸角增加了12.9°，11例中4例內(nèi)固定失敗。而骨折復(fù)位的保持是患者預(yù)后的重要參數(shù)。

AnotherstudybyMcLainetal3reported3methodsoffailureoftheseconstructs(n?19):progressivekyphosissecondarytothebendingofscrews(6patients),kyphosissecondarytoosseouscollapseorvertebraltranslationwith?outbendingofthehardware(3patients),andsegmentalkyphosisafteracaudadscrewinthelumbarconstructbroke(1patient,whohadhadacombinedinstrumentationformultiplefractures).Patientswhohadprogressivekyphosisofmorethan10°hadsubstantiallymorepainthandidthosewhohadlittleornoprogression.Ebelkeetal34pointedouttheimportanceofanteriorcolumnsupportinhissurvivor-shipanalysisin21patientswithburstfractureswhoweretreatedwithashortconstructeitherwithtranspedicularanterioraugmentation(n?13)andwithoutanterioraug?mentation(n?8).Thepatientstreatedwiththeanterioraugmentationhada100%survivalafter22months,whereasthegroupwithoutaugmentationhada50%survivalrateat19months.Recurrenceofkyphosisaftershortsegmentpedi?clescrew?xationraisesthequestionastowhetheranteriorcolumnaugmentationwithballoon-assistedendplatereduc?tionisbene?cial.

在另一項(xiàng)研究中，McLain等報(bào)道了內(nèi)固定失敗的三種形式（n=19）：螺釘彎曲引起進(jìn)行性后凸（6例）、骨塌陷或椎體滑移，沒有內(nèi)植物彎曲（3例）、腰椎上的尾側(cè)螺釘斷裂形成節(jié)段后凸（1例，由于多處骨折采用聯(lián)合固定）。進(jìn)行性后凸角度超過10°者，較沒有或很少進(jìn)行性后凸者更疼痛。Ebelke等在21例爆裂骨折中采用短節(jié)段固定，13例加以經(jīng)椎弓根增強(qiáng)，8例沒有增強(qiáng)的生存分析中指出了前柱支撐的重要性，有前側(cè)增強(qiáng)者，22個(gè)月隨訪時(shí)存活良好。沒有前側(cè)增強(qiáng)者，19個(gè)月隨訪時(shí)，有50%出現(xiàn)了失敗。經(jīng)椎弓根短節(jié)段固定后后凸畸形的再發(fā)引發(fā)球囊輔助終板復(fù)位前柱增強(qiáng)是否有益的問題。Magneticresonanceimagingappearstobeaveryhelpfulinassessingendplatecomminution,andposteriorligamentouscomplexinvolvementaftervertebralfracture.Onecadavericstudysuggeststhatshortsegmental?xationincombinationwithkyphoplastycanbeappliedtotypeBandCinjurieswithdisruptedposteriorlongitudinalligament.19Theroleoftheposteriorlongitudinalligamentfortheindirectreductionandsafetyoftheballoon-assistedendplatereductionisques?tionedinthisstudy.19

MRI對(duì)判斷終板粉碎及后側(cè)韌帶損傷十分有用。一項(xiàng)尸體研究建議，短節(jié)段固定聯(lián)合后凸成形可用于后縱韌帶斷裂的B型和C型骨折。該研究對(duì)后縱韌帶在間接復(fù)位中的作用及球囊輔助終板復(fù)位的安全性提出了質(zhì)疑。

Technique

Balloonaugmentedvertebralendplatereductionisperformedunderanesthesiaandantibioticprophylaxis.Ideally,reductionisassistedbyproperpositioningofthepatientpronewithslightlordosisonaradiolucenttable.Then,theposteriorinstrumen?tationisimplantedineitheranopenorpercutaneousmanner.Ifnecessary,slightdistractionthroughtheposteriorinstrumenta?tioncanbeappliedtoassistinfracturereduction.Anin?atableballoontampisthenusedtorestorethevertebralbodyheight,andcorrectthevertebralendplatecollapsebeforeinjectionofthebonecement.Atrans-orextrapedicularapproachforky-phoplastycanbeused(Figs.3and4).

技術(shù)

球囊擴(kuò)張椎體終板復(fù)位術(shù)要在麻醉下進(jìn)行，并使用抗生素預(yù)防感染。俯臥于透X線床上，保持輕度脊柱前凸的正確位置有助于復(fù)位。而后切開或經(jīng)皮植入后側(cè)器械。必要時(shí)可將后側(cè)器械輕度撐開，以利于復(fù)位。而后置入可擴(kuò)張的球囊恢復(fù)椎體高度，復(fù)位終板，而后注入骨水泥。經(jīng)椎弓根或椎弓根外入路均可應(yīng)用（圖3、圖4）。

Choiceoftheapproachdependsonthepathoanatomyofthefracturetoachieveamaximumreductionoftheend-plates.Itisbelievedtobeimportantthatthein?atablebonetampsaredirectedtowardthefracturelinesinthecaseofatraumaticfracturetofacilitatefracturereduction.Afterini?tiallyaccessingthevertebralbody,workingcannulasareplacedovertheguidewires.Balloonsizedependsonthevertebralbodysize.Thein?atablebonetampisplacedintheanteriorthirdofthevertebraetominimizetheriskofposte?riorfragmentdisplacementinthecanal.Balloonsarein?atedbilaterallysimultaneously.Inyoungpatient,200psiarequicklyobtainedwithlowinjectionvolumes.Theinitialpressureshoulddecreasewhiletheendplatesarebeingre?duced.Whenthedesiredreductionisachieved,bothbal?loonsareremovedandthecementisinjectedintothecavity.Incaseoflossofreductionthisprocedurecanberepeated.Especiallywithposterior?xation,earlymobilizationcanbeachieved.入路的選擇取決于骨折的病理解剖，以使終板獲得最大程度的復(fù)位。對(duì)于創(chuàng)傷骨折而言，將可擴(kuò)張球囊桿置入骨折線是很重要的，這有利于骨折復(fù)位。一旦進(jìn)入椎體，就可以通過導(dǎo)絲置入工作套管。球囊的大小取決于椎體的大小。球囊置入椎體的前三分之一，以減少后側(cè)骨塊移位入椎管的危險(xiǎn)。球囊要雙側(cè)同時(shí)進(jìn)行擴(kuò)張。在年輕患者，只要注入少量即可使壓力達(dá)到200磅，當(dāng)終板復(fù)位時(shí)，初始?jí)毫蜁?huì)下降。獲得滿意的