Balloon-AssistedFractureReductioninHigh-EnergyBurstFractures球囊輔助復位在高能量爆裂骨折中的應用

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

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

對于某些高能量爆裂骨折而言，經皮椎體增強聯合后路器械固定是一個很有吸引力選擇。有些生物材料，如磷酸鈣骨水泥，具有良好的生物相容性，與骨的生物力學特性相似，可以逐漸被宿主骨替代。早期生物力學和臨床結果顯示，前柱獲得了恢復，不需要再進行傳統的前路手術。還需要更多的臨床研究來證實這種微創方法對患者結果的促進作用。KEYWORDSburstfracture,percutaneus,balloon-assisted,reduction

關鍵詞：爆裂骨折，經皮，球囊輔助，復位。

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、后路或環形融合進行治療。傳統后側張力帶結構常采用鉤棒或釘棒結構來提供穩定和重建矢狀面平衡。韌帶整復術有助于復位椎體。盡管早期復位非常好，如果前柱支持不足，可能導致復位丟失、內固定失效、甚至治療失敗。前柱缺損可由于椎體骨折和椎間盤組織經終板嵌入骨折椎體引起，而這是無法通過后路器械進行間接復位的。通過更廣泛的前路手術進行器械固定支撐、cage植入等方法可以有效恢復前柱支撐，減少節段活動。但是前路手術的創傷較大，且住院時間更長，出血更多，增加了外科手術率，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，經皮器械和經皮椎體增強技術（后凸成形和椎體成形術）已成為外科手段。對于骨質疏松性骨折，后凸成形術已被證實是十分安全有效的。然而高能量爆裂骨折與骨質疏松性骨折的病理解剖是不同的。骨質疏松性骨折有三種骨折形式：楔形、爆裂、雙凹，后壁和終板多數是完整的。而且，骨質疏松的骨骼由于骨小梁減少，連接力降低，當球囊擴張時，可擠壓松軟的松質骨，抬高終板，從而恢復椎體高度。

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荷引起，至少可使前柱和中柱的壓縮破壞。突然的軸向負荷可破壞椎體終板，使鄰近的椎間盤組織疝入椎體。大多數爆裂骨折可引起椎管侵害，骨塊特別常來自上終板。進行性神經損害、進行性后凸、放射學證實的后柱不穩、椎體高度喪失大于50%伴有后凸者被認為是不穩定。骨折和凹陷的終板增加了椎間盤疝入椎體、局部畸形、治療失敗的機會。這樣一來，對胸腰椎爆裂骨折通過間接復位輔以球囊擴張使終板復位就可以重建前柱和終板的穩定，從而保持矢狀序列的長期穩定。微創的優勢在于恢復快、疼痛輕、減少了外科手術率、由于對組織破壞少，可能更穩定。Transpedicularvertebralcancellousbonegraftingforthetreatmentofvertebralcompressionfractureshasbeende?scribedinthepublisheddatawithlittlesuccessinmaintain?ingtheanteriorcolumnofthespineandwasassociatedwithahighfailurerate.11-15Transpedicularhydroxyapatitestickgraftingisanothertechnique,whichiscurrentlyunderinves?tigation.16經椎弓根植骨治療椎體壓縮骨折，文獻報道難以維持前柱，并有很高的失敗率。近來導航下經椎弓根羥基磷灰石棒植入是另一項技術。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.基礎研究

Mermelstein等研究發現，磷酸鈣骨水泥可以強化爆裂骨折的前柱，減少椎弓根釘的的壓力。在另一項尸體研究中，采用球囊復位終板，短節段固定，使椎體高度和終板解剖顯著恢復，該研究采用三維X線對從骨折－球囊擴張終板復位－骨水泥注入的不同階段進行詳細觀測，他們發現球囊取出后椎體不會塌陷，骨水泥注入后椎體高度得以保持，沒有骨水泥滲漏。另一項研究調查了后縱韌帶在胸腰椎爆裂骨折球囊輔助終板復位中的作用。在一個人類尸體爆裂骨折模型中，采用短節段固定輔以后凸成形，評估前后骨塊移位。雖然球囊擴張時前后骨塊發生移位，但球囊收縮時，這種作用就減小了，且椎體內注入骨水泥后，也沒有再發生。其移位的程度（＜1mm）沒有臨床意義。根據這項研究，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位技術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線進行隨訪1個月。后縱韌帶損傷者排除在外。短節段椎弓根釘固定后，采用CPC進行球囊輔助后凸成形術。可拆式塑料夾克固定8周。3例患者發生骨水泥滲漏（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另一項研究有18例病人（64±15歲），嚴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小時內采用后路經皮短節段固定CPC球囊后凸成形術，隨訪22個月。后凸從平均16°恢復至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個月，沒有嚴重并發癥發生（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.

一項單獨采用CPC后凸成形治療沒有神經損害的MagerlA型骨折的病例回顧中，術后7天疼痛視覺模糊評分從術前8.7分恢復至3.1分，術后30個月恢復至1分。RolandMorris殘疾評分在術后早期也相應下降。兩例前壁穿孔，6例術后CT發生骨水泥滲漏入椎間隙，1例少量滲漏至椎管側方。所有病人沒有出現神經或血管并發癥。30個月隨訪沒有長期并發癥。20%在術后1年CT觀察時骨水泥吸收替代，從術后即時至術后30個月的矯正丟失為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。

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材料與骨質疏松骨折是不同的。水泥必須可以通過管道注入，易于處理，適當的粘稠性，有足夠的工作時間（15min），較低的固化溫度，適當和持續的力學性質，不透X線，生物相容性，生物活性，和低降解性等。對于高能量爆裂骨折的最合適力學性質還沒有定論。硬度和強度應該與宿主骨相似。目前，聚甲基丙烯酸甲酯（PMMA）水泥廣泛用于椎體強化，在體內體外均有較長的應用史。固化過程會產生發熱反應，這對疼痛性骨質疏松性骨折是合適的，但對高能量椎體骨折可能會損傷其愈合潛力。PMMA無法降解，且在壓力強度上遠高于宿主骨。Incontrast,theimmediatemechanicalpropertiesofCPCareclosertobone;however,themechanicalpropertiesdur?ingtheresorptivephaseareimportantaswell.Thereissomeevidencethatboneformedunderthein?uenceofCPChassimilarmechanicalpropertiestonativehostboneduringitsresorptivephase.26,27InmoststudiesCPChasbeenused.Itconsistsof61%alphatricalciumphosphate,26%calcium-hydrogeno-phosphate,and3%hydroxylapatite.

相對而言，CPC的力學特性更接近于骨，但在吸收階段的力學特性也是很重要的。有證據表明，在CPC吸收期間形成的骨與自然宿主骨有相似的力學特性。CPC已用于大多數研究中。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分鐘后變為糊狀，在37℃條件下，初始固化時間為3分鐘，最終固化時間為7.5分鐘，不產熱。3天壓強達到60Mpa。在動物模型中，6個月后誘導骨形成，沒有細胞毒作用。然而，CPC的本身較脆，其抗張性低于PMMA。還要做更多循環負荷下的生物力學研究，特別是CPC單獨應用沒有后側固定的情況下。Anotherimportantconsiderationistheinteractionofthecementwiththeintervertebraldisktissue.Becausewewouldnotonlyexpectdirectcontactofcementwithhostbone,butalsowiththeintervertebraldisktissue,itseffectsonthevia?bilityofthediskbecomeimportant.32另一個要考慮的重要問題是水泥與椎間盤組織的反應。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.適應癥

后凸成形結合后側固定大多數報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癥，他推斷有些并發癥可通過MRI預見。對于一個胸腰椎骨折年紀較輕、前柱受累的非手術治療患者，持續的疼痛意味著后凸角可能增大。大多數后凸角增大的機制在于椎間盤組織進行性疝入骨折的終板和椎體中。對于手術的患者，粉碎的終板(特別是中央終板)、后凸的角度、及后縱韌帶復合體是否受累等可以推斷后凸畸形是否再發生。但他們發現疼痛與放射異常之間沒有顯著的相關性。Infact,traditionalshortsegmentposterior?xationispronetoanteriorspinalcolumnfailure.Krameretal2fol?lowedup11patientstreatedwithshortsegmentalinstru?mentationandposterolateralfusion.Duringthe2-yearfol?low-upperiod,thekyphosisangleincreasedby12.9°andtheconstructfailedin4of11patients.Furthermore,themain?tenanceoffracturereductionwasmostpredictiveofpatients’outcomeparameters.實際上，傳統的后側短節段固定易于出現前柱衰竭，Kramer等隨訪了11例短節段固定后外側融合的患者，隨訪2年，后凸角增加了12.9°，11例中4例內固定失敗。而骨折復位的保持是患者預后的重要參數。

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.

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

MRI對判斷終板粉碎及后側韌帶損傷十分有用。一項尸體研究建議，短節段固定聯合后凸成形可用于后縱韌帶斷裂的B型和C型骨折。該研究對后縱韌帶在間接復位中的作用及球囊輔助終板復位的安全性提出了質疑。

Technique

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

技術

球囊擴張椎體終板復位術要在麻醉下進行，并使用抗生素預防感染。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位。而后切開或經皮植入后側器械。必要時可將后側器械輕度撐開，以利于復位。而后置入可擴張的球囊恢復椎體高度，復位終板，而后注入骨水泥。經椎弓根或椎弓根外入路均可應用（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位。對于創傷骨折而言，將可擴張球囊桿置入骨折線是很重要的，這有利于骨折復位。一旦進入椎體，就可以通過導絲置入工作套管。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，以減少后側骨塊移位入椎管的危險。球囊要雙側同時進行擴張。在年輕患者，只要注入少量即可使壓力達到200磅，當終板復位時，初始壓力就會下降。獲得滿意的