球囊辅助复位在高能量爆裂骨折中的应用

Balloon-AssistedFractureReductioninHigh-EnergyBurstFractures球囊辅助复位在高能量爆裂骨折中的应用

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

Thecombinationofpercutaneusvertebralaugmentationwithposteriorinstrumentationmaybeanattractivetreatmentoptionforcertainhighenergyburstfractures.Biomaterialssuchascalciumphosphatecementarebiocompatible,sharesimilarbiomechanicalprop¬ertiestobone,andaregraduallyreplacedbyhostbonetissue.Earlybiomechanicalandclinicalresultsindicatethattheanteriorcolumnmayberestoredwithouttheneedofatraditionalanteriorsurgicalapproach.Furtherclinicalstudiesareneededtoconfirmthatthislessinvasiveapproachimprovespatientoutcome.SeminSpineSurg22:67-72©2010ElsevierInc.Allrightsreserved.

对于某些高能量爆裂骨折而言，经皮椎体增强联合后路器械固定是一个很有吸引力选择。有些生物材料，如磷酸钙骨水泥，具有良好的生物相容性，与骨的生物力学特性相似，可以逐渐被宿主骨替代。早期生物力学和临床结果显示，前柱获得了恢复，不需要再进行传统的前路手术。还需要更多的临床研究来证实这种微创方法对患者结果的促进作用。KEYWORDSburstfracture,percutaneus,balloon-assisted,reduction

关键词：爆裂骨折，经皮，球囊辅助，复位。

high-energythoracolumbarburstfracturescanbetreatedwithdecompressionandanterior,posterior,orcircum¬ferentialfusion.Traditionally,reconstructionoftheposteriortensionbandwitharodhookorrodscrewconstructisap¬pliedtoassistinprovidingstabilityandreestablishingthesagittalbalance.Ligamentotaxismayalsoassistinreducingthevertebra.Despiteexcellentinitialfracturereduction,in¬adequateanteriorcolumnsupportmayleadtolossofreduc¬tion,poorlong-termfixation,orevenfailureoftreatmentovertime.1-3Insufficiencyoftheanteriorcolumniscausedbyboththevertebralbodyfractureandalsomigrationofthedisktissuethroughtheendplateintothefracturedvertebralbody,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减压，前路、后路或环形融合进行治疗。传统后侧张力带结构常采用钩棒或钉棒结构来提供稳定和重建矢状面平衡。韧带整复术有助于复位椎体。尽管早期复位非常好，如果前柱支持不足，可能导致复位丢失、内固定失效、甚至治疗失败。前柱缺损可由于椎体骨折和椎间盘组织经终板嵌入骨折椎体引起，而这是无法通过后路器械进行间接复位的。通过更广泛的前路手术进行器械固定支撑、cage植入等方法可以有效恢复前柱支撑，减少节段活动。但是前路手术的创伤较大，且住院时间更长，出血更多，增加了外科手术率，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,theosteoporoticbonewithdecreasednumberandconnectivityoftrabeculaeallowsrestorationofthevertebralheightasballoontampinflationcompressesthesoftcancellousboneandelevatestheendplates.7,10近来，经皮器械和经皮椎体增强技术（后凸成形和椎体成形术）已成为外科手段。对于骨质疏松性骨折，后凸成形术已被证实是十分安全有效的。然而高能量爆裂骨折与骨质疏松性骨折的病理解剖是不同的。骨质疏松性骨折有三种骨折形式：楔形、爆裂、双凹，后壁和终板多数是完整的。而且，骨质疏松的骨骼由于骨小梁减少，连接力降低，当球囊扩张时，可挤压松软的松质骨，抬高终板，从而恢复椎体高度。

Incontrast,high-energytraumaticburstfracturesareusu¬allycausedbysubstantialaxialloading,whichresultsincom¬pressionfailureofatleastthemiddleandanteriorspinalcolumn.Thesuddenaxialloadresultsinavertebralendplatefailureasadjacentdisktissueisdrivenintothevertebralbody.Thevastmajorityofburstfracturescausesomecanalcompromise,typicallybecauseofosseousfragmentsfromthesuperiorendplate.Determinantsofinstabilityareprogressiveneurologicaldeficit,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轴向负荷引起，至少可使前柱和中柱的压缩破坏。突然的轴向负荷可破坏椎体终板，使邻近的椎间盘组织疝入椎体。大多数爆裂骨折可引起椎管侵害，骨块特别常来自上终板。进行性神经损害、进行性后凸、放射学证实的后柱不稳、椎体高度丧失大于50%伴有后凸者被认为是不稳定。骨折和凹陷的终板增加了椎间盘疝入椎体、局部畸形、治疗失败的机会。这样一来，对胸腰椎爆裂骨折通过间接复位辅以球囊扩张使终板复位就可以重建前柱和终板的稳定，从而保持矢状序列的长期稳定。微创的优势在于恢复快、疼痛轻、减少了外科手术率、由于对组织破坏少，可能更稳定。Transpedicularvertebralcancellousbonegraftingforthetreatmentofvertebralcompressionfractureshasbeende¬scribedinthepublisheddatawithlittlesuccessinmaintain¬ingtheanteriorcolumnofthespineandwasassociatedwithahighfailurerate.11-15Transpedicularhydroxyapatitestickgraftingisanothertechnique,whichiscurrentlyunderinves¬tigation.16经椎弓根植骨治疗椎体压缩骨折，文献报道难以维持前柱，并有很高的失败率。近来导航下经椎弓根羟基磷灰石棒植入是另一项技术。BasicScienceStudies

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

Anotherstudyinvestigatedtheroleofthelongitudinallig¬amentsduringballoon-assistedendplatereductioninthora¬columbarburstfractures.19Inahumancadavericburstfrac¬turemodel,theanteriorandposteriorbonedisplacementwasassessedafterapplyingshortsegmentalfixationfollowedbykyphoplasty.Althoughanteriorboneandposteriorbonedisplacementoccurredwiththeinflationoftheballoons,theeffectsubsidedafterdeflationanddidnotrecurwithinjec¬tionofthecement.Theamountofdisplacement(�1mm)wasthoughttobeoflittleclinicalsignificance.Accordingtothisstudy,anintactposteriorlongitudinalligamentdoesnotappeartobenecessarytopreventposteriorbonedisplace¬ment.Theycouldalsonotconfirmtheimportanceoftheposteriorlongitudinalligamentwithreductionthroughliga¬mentotaxis.基础研究

Mermelstein等研究发现，磷酸钙骨水泥可以强化爆裂骨折的前柱，减少椎弓根钉的的压力。在另一项尸体研究中，采用球囊复位终板，短节段固定，使椎体高度和终板解剖显著恢复，该研究采用三维X线对从骨折－球囊扩张终板复位－骨水泥注入的不同阶段进行详细观测，他们发现球囊取出后椎体不会塌陷，骨水泥注入后椎体高度得以保持，没有骨水泥渗漏。另一项研究调查了后纵韧带在胸腰椎爆裂骨折球囊辅助终板复位中的作用。在一个人类尸体爆裂骨折模型中，采用短节段固定辅以后凸成形，评估前后骨块移位。虽然球囊扩张时前后骨块发生移位，但球囊收缩时，这种作用就减小了，且椎体内注入骨水泥后，也没有再发生。其移位的程度（＜1mm）没有临床意义。根据这项研究，完整的后纵韧带无法阻止后方骨块的移位。他们也无法确定韧带复位技术中后纵韧带的重要性。ClinicalStudies

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

Afzal等报道了16例（年龄，22－53岁）高能量爆裂骨折病例（12例DenisB型,4例DenisC型爆裂骨折），临床与X线进行随访1个月。后纵韧带损伤者排除在外。短节段椎弓根钉固定后，采用CPC进行球囊辅助后凸成形术。可拆式塑料夹克固定8周。3例患者发生骨水泥渗漏（2例在椎管，1例在椎间隙），没有临床症状。没有发生后壁移位，平均后凸角减少10°。

Anotherinvestigationincluded18patients(64�15years)withseverethoracolumbarburstandcompressionfractures(Figs.2-4).21Allpatientsweretreatedwithshortsegmentpercutaneousposteriorinstrumentationandbal¬loonkyphoplastywithCPCwithin24hoursofinjuryandwerefollowedupfor22months.Kyphosisimprovedfromanaverageof16°-2°.Cementleakagewasobservedonlyante¬riortothevertebralbodywithoutclinicalsequelae.Asecondstudybythesamegrouptreatingthoracolumbarburstfrac¬tureswithcalciumphosphateandanopenapproachforpos¬teriorspinalinstrumentationshowedsimilarlyencouragingresultsat24monthswithoutmajorcomplications(Fig.1).22另一项研究有18例病人（64±15岁），严重的胸腰椎爆裂和压缩骨折（图2－4）。所有的病人都在伤后24小时内采用后路经皮短节段固定CPC球囊后凸成形术，随访22个月。后凸从平均16°恢复至2°。骨水泥仅渗漏至椎体前方，没有后遗症。同一小组采用羟基磷灰石和开放后路固定取得了相似的效果，随访24个月，没有严重并发症发生（图1）。AprospectivecaseseriesonstandalonekyphoplastywithCPCinMagerltypeAfractureswithoutdeficitnotedadecreaseofpainonthevisualanaloguescalefrom8.7preoperativelyto3.1postoperativelyin7days,and1atthelastfollow-upat30months.23TheRolandMorrisDisabilityscoredemonstratedasimilardecreaseintheearlypostoper¬ativetimeperiod.Twoanteriorwallperforationsbycannulasduringtheprocedure,and6cementleakageswereobservedonpostoperativecomputedtomography(CT)scans(5casesintothediskspace,1casewithsmallleakageinthelateralportionofthespinalcanal).Allwerewithoutneurologicalorvascularconsequences.Also,nolong-termcomplicationswereobservedatthelast30monthfollowup.Twentyper¬centcementresorptionandsubstitutionwasnotedonCTscansat1yearpostoperatively.Lossofcorrectionwas9°(0°-17°)fromimmediatepostoperativelytothelastfol¬low-upat30months.Thismayrelatetolossofvertebralheightastheresorbablecementisremodeled.

一项单独采用CPC后凸成形治疗没有神经损害的MagerlA型骨折的病例回顾中，术后7天疼痛视觉模糊评分从术前8.7分恢复至3.1分，术后30个月恢复至1分。RolandMorris残疾评分在术后早期也相应下降。两例前壁穿孔，6例术后CT发生骨水泥渗漏入椎间隙，1例少量渗漏至椎管侧方。所有病人没有出现神经或血管并发症。30个月随访没有长期并发症。20%在术后1年CT观察时骨水泥吸收替代，从术后即时至术后30个月的矫正丢失为9°（0°－17°），这可能与可吸收骨水泥吸收后引起的高度丢失有关。

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.PMMAisnondegradableandissignificantlystrongerincompressionthanthehostbone.24-26

充填物的选择

高能量胸腰椎爆裂骨折椎体增强材料与骨质疏松骨折是不同的。水泥必须可以通过管道注入，易于处理，适当的粘稠性，有足够的工作时间（15min），较低的固化温度，适当和持续的力学性质，不透X线，生物相容性，生物活性，和低降解性等。对于高能量爆裂骨折的最合适力学性质还没有定论。硬度和强度应该与宿主骨相似。目前，聚甲基丙烯酸甲酯（PMMA）水泥广泛用于椎体强化，在体内体外均有较长的应用史。固化过程会产生发热反应，这对疼痛性骨质疏松性骨折是合适的，但对高能量椎体骨折可能会损伤其愈合潜力。PMMA无法降解，且在压力强度上远高于宿主骨。Incontrast,theimmediatemechanicalpropertiesofCPCareclosertobone;however,themechanicalpropertiesdur¬ingtheresorptivephaseareimportantaswell.ThereissomeevidencethatboneformedundertheinfluenceofCPChassimilarmechanicalpropertiestonativehostboneduringitsresorptivephase.26,27InmoststudiesCPChasbeenused.Itconsistsof61%alphatricalciumphosphate,26%calcium-hydrogeno-phosphate,and3%hydroxylapatite.

相对而言，CPC的力学特性更接近于骨，但在吸收阶段的力学特性也是很重要的。有证据表明，在CPC吸收期间形成的骨与自然宿主骨有相似的力学特性。CPC已用于大多数研究中。其由61%的α磷酸三钙、26%磷酸氢钙、3%5。

ThisalphatricalciumcementismarketedasCalcibon(Bi¬omet,Merck,Wehrheim,Germany).Mixedwithliquid-to¬powderratioof0.35,apasteisobtainedwithacohesiontimeof1minute,aninitialsettingtimeof3minutes,andafinalsettingtimeof7.5minutesat37°Cwithoutanexothermicreaction.Acompressivestrengthof60Mpaisobtainedat3days.26,28Anosteoconductivepotentialafter6monthswith¬outcellulartoxicitywasshowninananimalmodel.26,29-31However,CPCsareinherentlybrittlewithinferiortensilepropertiescomparedwithPMMA.Furtherbiomechanicalstudiesundercyclingloadingareneeded,especiallywhenCPCisusedwithoutposteriorfixation.这种α三钙水泥的商品名为Calcibon(Bi¬omet,Merck,Wehrheim,Germany),其液体与粉的比率为0.35，混合1分钟后变为糊状，在37℃条件下，初始固化时间为3分钟，最终固化时间为7.5分钟，不产热。3天压强达到60Mpa。在动物模型中，6个月后诱导骨形成，没有细胞毒作用。然而，CPC的本身较脆，其抗张性低于PMMA。还要做更多循环负荷下的生物力学研究，特别是CPC单独应用没有后侧固定的情况下。Anotherimportantconsiderationistheinteractionofthecementwiththeintervertebraldisktissue.Becausewewouldnotonlyexpectdirectcontactofcementwithhostbone,butalsowiththeintervertebraldisktissue,itseffectsonthevia¬bilityofthediskbecomeimportant.32另一个要考虑的重要问题是水泥与椎间盘组织的反应。我们要想到水泥不仅与宿主骨直接接触，而且与椎间盘组织接触，其对椎间盘活力的影响变得十分重要。Indications

MostreportsofkyphoplastywithposteriorfixationhavebeendescribedafteratypeA3injurywithintactposteriorlongitudinalligament.Oneretal33analyzedcomplicationsofcommontreatmentschemesofthoracolumbarfractures.Heconcludesthatsomeofthecomplicationscanbepredictedwithmagneticresonanceimaging.Inthecaseofnonopera¬tivelytreatedlow-gradethoracolumbarfracturespatients’ageandanteriorcolumnsinvolvementappearedtobepredictiveofsubsequentincreaseofthekyphoticangleaswellasper¬sistentpain.Themostcommonmechanismofkyphosisin¬creasewasthroughaprogressivesettlingofthediskintothefracturedendplateandvertebralbody.Intheoperativegroupahighdegreeofendplatecomminution(especiallyofthecentralendplate),theamountofkyphosisreductionandin¬volvementoftheposteriorlongitudinalligamentcomplexwaspredictiveofkyphosisrecurrence.However,theyfoundnosignificantcorrelationbetweenpainandradiographicfindings.适应症

后凸成形结合后侧固定大多数报道用于后纵韧带完整的A3型骨折。Oner等分析了一般胸腰椎骨折治疗方案的并发症，他推断有些并发症可通过MRI预见。对于一个胸腰椎骨折年纪较轻、前柱受累的非手术治疗患者，持续的疼痛意味着后凸角可能增大。大多数后凸角增大的机制在于椎间盘组织进行性疝入骨折的终板和椎体中。对于手术的患者，粉碎的终板(特别是中央终板)、后凸的角度、及后纵韧带复合体是否受累等可以推断后凸畸形是否再发生。但他们发现疼痛与放射异常之间没有显著的相关性。Infact,traditionalshortsegmentposteriorfixationispronetoanteriorspinalcolumnfailure.Krameretal2fol¬lowedup11patientstreatedwithshortsegmentalinstru¬mentationandposterolateralfusion.Duringthe2-yearfol¬low-upperiod,thekyphosisangleincreasedby12.9°andtheconstructfailedin4of11patients.Furthermore,themain¬tenanceoffracturereductionwasmostpredictiveofpatients’outcomeparameters.实际上，传统的后侧短节段固定易于出现前柱衰竭，Kramer等随访了11例短节段固定后外侧融合的患者，随访2年，后凸角增加了12.9°，11例中4例内固定失败。而骨折复位的保持是患者预后的重要参数。

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¬clescrewfixationraisesthequestionastowhetheranteriorcolumnaugmentationwithballoon-assistedendplatereduc¬tionisbeneficial.

在另一项研究中，McLain等报道了内固定失败的三种形式（n=19）：螺钉弯曲引起进行性后凸（6例）、骨塌陷或椎体滑移，没有内植物弯曲（3例）、腰椎上的尾侧螺钉断裂形成节段后凸（1例，由于多处骨折采用联合固定）。进行性后凸角度超过10°者，较没有或很少进行性后凸者更疼痛。Ebelke等在21例爆裂骨折中采用短节段固定，13例加以经椎弓根增强，8例没有增强的生存分析中指出了前柱支撑的重要性，有前侧增强者，22个月随访时存活良好。没有前侧增强者，19个月随访时，有50%出现了失败。经椎弓根短节段固定后后凸畸形的再发引发球囊辅助终板复位前柱增强是否有益的问题。Magneticresonanceimagingappearstobeaveryhelpfulinassessingendplatecomminution,andposteriorligamentouscomplexinvolvementaftervertebralfracture.OnecadavericstudysuggeststhatshortsegmentalfixationincombinationwithkyphoplastycanbeappliedtotypeBandCinjurieswithdisruptedposteriorlongitudinalligament.19Theroleoftheposteriorlongitudinalligamentfortheindirectreductionandsafetyoftheballoon-assistedendplatereductionisques¬tionedinthisstudy.19

MRI对判断终板粉碎及后侧韧带损伤十分有用。一项尸体研究建议，短节段固定联合后凸成形可用于后纵韧带断裂的B型和C型骨折。该研究对后纵韧带在间接复位中的作用及球囊辅助终板复位的安全性提出了质疑。

Technique

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

技术

球囊扩张椎体终板复位术要在麻醉下进行，并使用抗生素预防感染。俯卧于透X线床上，保持轻度脊柱前凸的正确位置有助于复位。而后切开或经皮植入后侧器械。必要时可将后侧器械轻度撑开，以利于复位。而后置入可扩张的球囊恢复椎体高度，复位终板，而后注入骨水泥。经椎弓根或椎弓根外入路均可应用（图3、图4）。

Choiceoftheapproachdependsonthepathoanatomyofthefracturetoachieveamaximumreductionoftheend-plates.Itisbelievedtobeimportantthattheinflatablebonetampsaredirectedtowardthefracturelinesinthecaseofatraumaticfracturetofacilitatefracturereduction.Afterini¬tiallyaccessingthevertebralbody,workingcannulasareplacedovertheguidewires.Balloonsizedependsonthevertebralbodysize.Theinflatablebonetampisplacedintheanteriorthirdofthevertebraetominimizetheriskofposte¬riorfragmentdisplacementinthecanal.Balloonsareinflatedbilaterallysimultaneously.Inyoungpatient,200psiarequicklyobtainedwithlowinjectionvolumes.Theinitialpressureshoulddecreasewhiletheendplatesarebeingre¬duced.Whenthedesiredreductionisachieved,bothbal¬loonsareremovedandthecementisinjectedintothecavity.Incaseoflossofreductionthisprocedurecanberepeated.Especiallywithposteriorfixation,earlymobilizationcanbeachieved.入路的选择取决于骨折的病理解剖，以使终板获得最大程度的复位。对于创伤骨折而言，将可扩张球囊杆置入骨折线是很重要的，这有利于骨折复位。一旦进入椎体，就可以通过导丝置入工作套管。球囊的大小取决于椎体的大小。球囊置入椎体的前三分之一，以减少后侧骨块移位入椎管的危险。球囊要双侧同时进行扩张。在年轻患者，只要注入少量即可使压力达到200磅，当终板复位时，初始压力就会下降。获得满意的