三维CT导航在腰椎再次手术及翻修术中椎弓根螺钉置入的应用研究(附13例报告)

目的探讨三维CT导航在腰椎再次手术及翻修手术椎弓根螺钉置入中的准确性及安全性。方法回顾性研究自2008年9月~2009年9月,收治因腰椎再次手术及翻修需进行椎弓根螺钉系统内固定13例,其中腰椎间盘术后继发椎管狭窄4例,腰椎置钉失败2例,全椎板或半椎板切除术后腰椎不稳4例、椎体滑脱3例。在减压解除神经根压迫同时在三维CT导航引导下行椎弓根螺钉固定矫形。采用术中G型臂X线机正侧位摄片与导航路径进行比较测量以及术后三维影像系统(CT、MRI)评估螺钉位置的准确性,螺钉完全位于椎弓根内为置钉位置准确,记录螺钉平均置入时间。结果共置入62枚螺钉,术中及术后X线片评估椎弓根螺钉置钉准确度为100%,术后三维影像评估螺钉位置准确率为91.8%,螺钉平均置入时间(4.7±0.7)min/枚,未出现螺钉置入相关的近期并发症。结论腰椎再次手术及翻修手术患者术中应用CT三维影像导航辅助行椎弓根螺钉置入,可以有效的提高置钉的精确性以及保证了安全性,降低了脊柱再次手术及翻修手术的风险性,减少放射线的暴露强度。     

球形探针技术在胸腰椎椎弓根螺钉置钉中的应用

目的通过与传统开路锥置钉技术比较,评价在胸腰椎椎弓根螺钉置钉中应用球形探针技术的准确性和安全性,探讨其临床应用价值。方法回顾性分析2016年1月—2017年2月新疆医科大学第一附属医院收治的需行胸腰椎椎弓根螺钉内固定治疗的106例患者临床资料,术中应用球形探针技术或传统开路锥技术置入椎弓根螺钉。其中56例采用直径2.5 mm球形探针穿刺(球形探针组),其余50例采用传统开路锥穿刺(传统组)。术后采用CT检查确认螺钉位置以评估置钉准确性。结果球形探针组共置入椎弓根螺钉296枚,传统组共置入264枚。术后CT显示球形探针组置钉准确率为97.64%,7枚置钉不良;传统组置钉准确率为83.71%,43枚置钉不良。2组置钉准确率及穿透椎弓根内侧、椎弓根外侧、椎体前壁骨皮质螺钉比例差异均有统计学意义(P<0.05)。2组术中出血量间差异无统计学意义(P>0.05)。传统组术后1例出现L5神经根损伤致足下垂;球形探针组术中、术后均未出现神经、血管、脑脊液漏或内脏损伤等并发症。结论与传统开路锥置钉技术相比,球形探针技术能更准确置入胸腰椎椎弓根螺钉,减少因螺钉位置不良导致的并发症。     

直视下胸腰椎椎弓根螺钉旋转置入法临床应用

目的 研究直视下胸腰椎椎弓根螺钉旋转置入法的成功率、安全性及可操作性方面的应用价值.方法 采用后路切口直视下旋转置入法治疗胸腰椎骨折41例,置钉166枚.结果 166枚椎弓根螺钉置入均获成功,大部分椎弓根螺钉平行了椎体的上下终板,仪有7例椎弓根螺钉与椎体的上下终板轻度成角(5°～10°),符合置钉要求,1例其中1枚螺钉置入位置偏下,术后轻度神经根刺激症状,术后四周症状完全消失.结论 直视下胸腰椎椎弓根螺钉旋转置入法更准确可靠,可有效防止硬膜及神经根的损伤.     

机器人辅助与徒手置钉在腰椎翻修术早期结果比较

[目的]比较Renaissance机器人系统辅助椎弓根螺钉置入与徒手椎弓根螺钉置入在腰椎翻修手术中的安全性及准确性。[方法]回顾性分析2018年1月~2018年12月在本院行腰椎后路翻修手术的病例69例,其中使用Renaissance机器人系统辅助椎弓根螺钉置入共31例,使用传统徒手椎弓根螺钉置入38例。记录临床资料,并根据术后CT对螺钉精度进行Gertzbein Robbins分级,比较螺钉置入准确性。[结果]两组患者手术时间、术后出血量及手术相关并发症等差异无统计学意义(P0.05)。机器人组术中出血量、术中透视次数显著少于徒手组(P0.05)。机器人辅助组共置入螺钉152枚,术后CT评估显示:A级置钉137枚,B级置钉11枚,C级置钉4枚,没有D、E级置钉,置钉准确率97.37%。徒手组共置入螺钉194枚,术后CT评估显示:A级置钉129枚,B级置钉48枚,C级置钉15枚,D级置钉2枚,没有发现E级置钉,置钉准确率91.24%。在螺钉精度分级及螺钉准确性方面,机器人组优于徒手组,差异具有统计学意义(P0.05)。[结论]与徒手置钉技术相比,Renaissance机器人系统辅助椎弓根螺钉置入在腰椎翻修手术中具有置钉精度高、且术中出血及术中透视次数少的优势。     

多层螺旋CT三维重建技术在胸腰椎骨折经椎弓根螺钉内固定术中的应用价值

目的:探讨多层螺旋CT(MSCT)三维重建技术在胸腰椎骨折患者经椎弓根螺钉内固定术中的应用价值。方法:2007年1月~2008年12月,78例胸腰椎骨折患者在我院行椎弓根螺钉内固定术,其中38例使用传统置钉法(Weinstein法或AO法)进行椎弓根螺钉置入(A组),40例采用MSCT三维重建设计钉道的置钉方法进行螺钉置入(B组),术后两组均复查胸腰椎正、侧位X线片和CT了解置入螺钉位置情况,应用Lonstein等的方法评判置钉准确率。结果:78例患者共置入椎弓根螺钉436枚,A组38例共置入212枚,12例32枚螺钉穿破椎弓根皮质,其中穿破椎弓根内外皮质21枚,穿破椎弓根上下皮质11枚,置钉准确率84.91%;B组40例共置入224枚,5例6枚螺钉穿破椎弓根皮质,其中穿破椎弓根内外皮质4枚,穿破椎弓根上下皮质2枚,置钉准确率97.33%。两组置钉准确率有统计学差异(P<0.05)。结论:胸腰椎骨折患者行椎弓根螺钉内固定时应用MSCT三维重建设计钉道的置钉方法较传统置钉方法成功率高。     

脊柱手术机器人在胸腰段窄小椎弓根后路螺钉置入中的应用

目的 探讨Renaissance脊柱手术机器人在胸腰段窄小椎弓根后路螺钉置入中的应用。方法 对156例胸腰段窄小椎弓根的脊柱疾病患者行后路螺钉置入,窄小椎弓根双侧中一侧采用脊柱手术机器人辅助置入椎弓根螺钉,另一侧采用传统方法置入椎弓根螺钉。术后采用Abul-Kasimhierarchy分级系统评价椎弓根螺钉置入的优良性。结果 在T10～L3窄小椎弓根共置入椎弓根螺钉456枚,其中胸椎置钉60枚,置钉优良率机器人辅助侧为93. 3%(28/30),传统手术侧为80. 0%(24/30),两侧比较差异有统计学意义(P 0. 05);腰椎置钉396枚,置钉优良率机器人辅助侧为96. 0%(190/198),传统手术侧为81. 8%(162/198),两侧比较差异有统计学意义(P 0. 05)。结论 Renaissance脊柱手术机器人辅助胸腰段窄小椎弓根螺钉置入能提高置钉优良率。     

个体化3D打印导向模板辅助胸腰椎椎弓根螺钉置入在强直性脊柱炎中的应用研究

目的 :评价个体化设计定制3D打印椎弓根螺钉导向模板辅助强直性脊柱炎(ankylosing spondylitis,AS患者胸腰椎椎弓根螺钉置入的准确性与安全性。方法:纳入2016年1月至2019年9月收治的8例AS患者的胸腰椎三维CT检查数据,利用Mimics 17.0、ideaMaker等计算机软件设计AS胸腰椎椎弓根螺钉导向模板,并利用3D打印机打印制作全部病例的实体模型(T_(10)-L_2),每例2份,分为导板辅助螺钉置入组(实验组)和徒手置钉组(对照组)。两组胸腰椎椎弓根螺钉均由同一名脊柱外科医师负责置入。根据术后CT影像结果评估两组椎弓根螺钉置入的准确性,并对螺钉置入情况进行分级:0级和1级螺钉为可接受置钉,2级和3级为不可接受置钉。同时比较术前3D打印软件虚拟设计的椎弓根螺钉的直径、长度、进钉点与后正中线的距离等指标与术中实际使用情况。结果:导板辅助螺钉置入组设计并打印出AS胸腰椎3D打印椎弓根螺钉导向模板23块,辅助置入螺钉46枚,可接受螺钉为44枚;置入单枚螺钉平均时间为(4.20±1.15) min,X线机透视次数为(5.00±1.25)次,置钉过程中螺钉和克氏针平均调整次数为(1.76±1.32)次。徒手置钉组使用传统影像学透视徒手方法置钉46枚,可接受螺钉30枚;置入单枚螺钉平均时间为(14.67±2.23) min,X线机透视次数为(14.46±2.21)次,螺钉和克氏针平均调整次数为(4.76±3.39)次。导板辅助螺钉置入组与徒手置钉组螺钉置入成功率分别为95.65%(44/46)和56.22%(30/46),差异有统计学意义(χ~2=13.538,P0.05);术前3D打印软件虚拟设计的椎弓根螺钉的直径、长度、进钉点与后正中线的距离,与术中实际使用情况差异无统计学意义(P0.05);导板辅助螺钉置入组置入单枚螺钉的时间、X线机透视次数及置钉过程中螺钉和克氏针平均调整次数均明显少于徒手置钉组(P0.01)。结论:3D打印技术定制个体化椎弓根螺钉导向模板显著提高了置钉的安全性、准确性及手术效率,尤其适用于AS合并骨折脱位等须行后路椎弓根螺钉固定的胸腰椎椎体。     

椎弓根钉固定在10岁以下小儿胸腰椎疾患治疗中的应用

目的：探讨10岁以下小儿胸腰椎椎弓根钉固定的可行性及安全性。方法：对19例平均年龄6．5岁的胸腰椎疾患患儿，2例骨折脱位患者采用后路短节段椎弓根钉复位固定；3例肿瘤患者采用后路切除肿瘤、短节段椎弓根钉固定；10例先天性半椎体患者采用后路半椎体切除、椎弓根钉矫形固定或前后联合手术；4例脊柱侧凸患者采用后路椎弓根钉矫形固定。椎弓根钉置入点及方向与成人相似，螺钉直径为拟固定椎弓根横径的80％～90％，长度达椎体的70％～80％。手术后观察各螺钉位置，随访观察内固定稳定性及神经功能情况。结果：共置入83枚椎弓根钉，术中3个椎弓根破裂造成矫形时螺钉松动，均上移或下移一个节段完成固定；术后检查3枚螺钉位置不良，因未造成神经损害，对固定的稳定性无影响，未做处理。无脊髓神经和血管损伤及感染。18例获得平均24个月随访，1例术后1年螺钉断裂进行了翻修，其余患者无内固定松动。3例术前有神经功能障碍的患者均有明显恢复。结论：在详细的术前计划，选择恰当直径的椎弓根钉、精湛的外科技术下行小儿胸腰椎椎弓根螺钉固定是安全可行的。     

胸腰椎经皮椎弓根螺钉置钉的准确性分析

目的:分析胸腰椎经皮椎弓根螺钉固定术的置钉准确性.方法:回顾分析2010年7月～2012年12月我院53例胸腰椎经皮椎弓根螺钉固定术患者,男31例,女22例;年龄18～73岁,平均51.2岁.腰椎退变性疾病24例,胸腰椎骨折29例.置钉节段为T8～S1.根据术后CT轴位扫描图像以及患者是否出现椎弓根螺钉相关并发症,将椎弓根螺钉位置分级:0级,螺钉位于椎弓根皮质内;1级,螺钉突破椎弓根骨壁但≤2mm;2级,螺钉突破椎弓根骨壁＞2mm,但无神经受压等症状;3级,出现螺钉相关并发症.结果:共置入椎弓根螺钉212枚,平均4.0枚/例.212枚螺钉中,0级175枚(82.5％);1级32枚(15.1％);2级4枚(1.9％);3级1枚(0.5％),患者出现神经受压症状,行翻修术.37枚位置不佳的螺钉中,24枚向内侧切出椎弓根,13枚向外侧切出.结论:胸腰椎经皮椎弓根螺钉固定技术虽置钉位置欠佳率较高,但很少发生2级以上置钉位置不佳者.     

低龄儿童脊柱侧凸矫正术中椎弓根螺钉置入的精确性和安全性评估

目的:评估10岁及以下脊柱侧凸患儿侧凸矫正术中椎弓根螺钉置入的精确性及安全性,并分析其相关影响因素。方法:回顾性分析2008年2月~2008年7月我院收治的行后路椎弓根螺钉固定的10岁及以下脊柱侧凸41例患儿的临床资料,所有患者术前、术后均行CT检查,男26例,女15例,年龄2~10岁,平均5.4岁。先天性脊柱侧凸36例,特发性脊柱侧凸2例,神经肌肉源性脊柱侧凸2例,先天性软骨发育不全伴脊柱侧凸1例。术中根据解剖标志徒手置入椎弓根螺钉。在PACS系统上通过Pacs Client软件测量螺钉尖距椎弓根内壁、外壁、上壁、下壁以及椎体前缘的距离。若左侧椎弓根螺钉穿破椎弓根外壁或椎体前缘,测量钉尖与主动脉的距离。根据椎弓根螺钉所在位置(节段、凹凸侧、脊椎发育是否异常)分析其破壁率差别。不良置钉定义为椎弓根螺钉穿破椎弓根内、外壁或椎体前缘的距离超过2mm,和椎弓根螺钉进入椎间孔或穿破终板进入椎间盘。结果:本组病例共置入242枚椎弓根螺钉,胸椎128枚,腰椎114枚,平均每例患者置入5.8枚螺钉。螺钉完全在椎弓根内208枚,占86.0%。破壁34枚(占14.0%),其中不良置钉18枚(占7.4%),18枚中有5枚穿破外壁,8枚穿破内壁,5枚穿破椎体前缘。形态异常椎和凹侧的椎弓根螺钉的破壁率较高(分别为24.1%和17.9%)。术中一枚螺钉拔出,未出现其他螺钉置入相关并发症。穿破椎体前缘螺钉距离主动脉距离平均2.3mm。结论:10岁及以下儿童椎弓根螺钉的徒手置入有较高的精确性和安全性,但在发育不良椎体及凹侧置钉时应谨慎。     

经皮植入椎弓根螺钉的CT扫描钉道分析和临床评价

目的：通过应用经皮穿刺植入椎弓根螺钉的后路固定系统治疗胸腰段骨折患者，以探究该微创技术的准确性和可行性。方法：应用菲力浦X线荧屏透视，经皮穿刺植入导针引导的空心椎弓根螺钉136枚，后路固定系统治疗胸腰段骨折34例。术后CT扫描观察钉道与椎弓根内侧壁、外侧壁的关系，钉尖与椎体前缘的距离、TSA角、SSA角，以及进行术后的初步临床疗效观察。结果：其中椎弓根内侧壁破裂4枚，椎弓根外侧壁破裂3枚，经皮椎弓根螺钉方向过于向头端偏斜2枚，过于向尾端偏斜1枚，经皮椎弓根螺钉钉尖稍穿透椎体前缘5枚，本组经皮椎弓根螺钉植钉失误率7．25％。结论：该技术具有一定的准确性和可行性，并发症发生率相对可以接受，但有较高操作要求，需要有经验的脊柱外科医生进行。本组病例在X线荧屏透视下完成，受辐射量大，后来植钉时透视次数明显减少，患者和医师受辐射量下降而且手术时间缩短，如结合导航技术将在微创脊柱外科领域中发挥相当作用。     

导航辅助脊柱胸腰段椎弓根钉植入的临床应用

目的探讨临床运用计算机影像导航技术引导脊柱胸腰段椎弓根钉植入的准确性。方法2003年5月-2007年5月，29例患者接受116枚计算机影像导航技术引导脊柱胸腰段椎弓根钉植入手术治疗，T10-T1250枚胸椎弓根钉，L1-L3 66枚腰椎弓根钉。术中记录椎弓根钉植入所需时间及C-臂透视工作次数，椎弓根钉植入完成后，即行C-臂正侧位摄片并与导航路径进行比较测量。术后CT进行椎弓根层面扫描，根据椎弓根钉与椎弓根皮质问关系分为四级：A=在椎弓根内；B=突破皮质，〈2mm；C=突破皮质，2-4mm；C=突破皮质，〉4mm。结果术后CT椎弓根位置扫描显示：A级101枚（87．07％）；B级10枚（8．62％）；C级2枚（1．72％）；D级3枚（2．59％）。1枚椎弓根钉植入平均所需时间：2．73±0．64min（1．15～4．02min）。下胸椎9枚（7．75％）胸椎弓根钉突破皮质，上腰椎6枚（5．17％）腰椎弓根钉突破皮质，且临床观察未发现与椎弓根钉突破皮质相关的神经血管等并发症。植入的椎弓根钉C-臂正侧位摄片与导航路径吻合比较，进钉点均差2．6mm（最大3．1mm），角度均差3．3°（最大5．4°）。结论计算机影像导航辅助脊柱胸腰段椎弓根钉植入，提供二维、多平面实时显示，保证了脊柱胸腰段椎弓根钉植入的准确性及安全性，明显减少放射线的暴露强度。     

胸腰椎椎弓根螺钉植入技术的研究进展

胸腰椎椎弓根螺钉内固定技术的开展，有力地推动了脊柱外科的发展。该技术的关键是，螺钉的植入必须位于三维空间中唯一的一个正确通道上，即按照正确的矢状面角及水平面角，沿椎弓根的长轴穿过椎弓根这一狭小的骨性管道达惟体内。近年来，胸腰椎椎弓根螺钉植入技术的研究取得了很大发展，尤其是术中监测手段，已从传统的X线透视或摄片监测定位发展到计算机辅助技术进行可视化监测。本文结合国内外研究成果，对胸腰椎椎弓根螺钉植入技术的研究进展进行概述。     

电磁影像导航技术在胸腰椎手术中的应用

目的：探讨电磁影像导航技术在胸腰椎手术中的应用价值。方法：对诊断为腰椎滑脱、腰椎管狭窄症、退行性腰椎侧凸的32例患者(男14例，女18例，平均年龄4l岁)在手术中应用电磁影像导航技术辅助进行椎弓根螺钉置入，10例同时行椎间融合器置入。术后均进行置入螺钉节段的X光平片及CT扫描以确定螺钉置入情况。结果：全组患者安全完成手术，手术时间平均2．8h(1．6～3．7h)，术后影像学检查结果显示所有螺钉置入位置准确。术中与术后无与螺钉置人相关的并发症发生。结论：应用电磁影像导航技术，可以辅助螺钉的准确置入，减少手术时间及放射线照射，尤其对脊柱畸形、严重退变病例或再次手术者，具有显著的优越性。     

Clinical evaluation and computed tomography scan analysis of screw tracts after percutaneous insertion of pedicle screws in the lumbar spine

STUDY DESIGN: An examination of the accuracy of percutaneous pedicle screw placement in the lumbar spine. Using computed tomography scan analysis after implant removal, the screw tracts could be analyzed regarding the degree and direction of screw dislocation. OBJECTIVES: To investigate the misplacement rate and related clinical complications of percutaneous pedicle screw insertion in the lumbar spine. SUMMARY OF BACKGROUND DATA: The feasibility of the external fixation test has been investigated in several studies. Although pedicle screw misplacement has been reported as one of the main complications, there are no reliable data on the misplacement rate for this difficult surgical procedure. METHODS: In this study, 51 consecutive patients with suspected segmental instability were investigated after external transpedicular screw insertion for the external fixation test. Computed tomography scans of all instrumented pedicles from L2 to S1 were performed after screw removal. The screw tracts were analyzed, and the direction and degree of the pedicle violations were noted. In addition, the screw and pedicle angles were measured. RESULTS: Of 408 percutaneously inserted pedicle screws, only 27 screws (6.6%) were misplaced. There were 19 medial pedicle violations, 6 lateral cortical defects, and only 1 cranial and 1 caudal displacement. With respect to the spinal level, S1 showed the highest misplacement rate, with 11 screw dislocations (12%). After surgery, found two nerve root injuries were found. Only one of the injuries (L4) was related to the malposition of a screw. CONCLUSIONS: This study has shown that percutaneous insertion of pedicle screws in the lumbar spine is a safe and reliable technique. Despite the low misplacement rate of only 6.6%, it should be kept in mind that the surgical procedure is technically demanding and should be performed only by experienced spine surgeons.     

Accuracy of fluoroscopic navigation of pedicle screws. CT-based evaluation of bone screw placement

While the advantages of C-arm navigation in computer-assisted spine surgery are obvious, the accuracy of pedicle screw placement with virtual fluoroscopy still needs to be verified. The C-arm-based ION system (Medtronic Sofamor Danek) was used to navigate pedicle screw insertion in patients undergoing spinal surgery for various conditions. In a prospective study, a total of 160 screws were inserted in the first 30 consecutive patients since introduction of the system at our institution: 54 at the thoracic spine (highest level: TH4) and 106 at the lumbar spine. Computed tomography (CT) scans were performed postoperatively by two independent radiologists to control the accuracy of screw placement at the level of the pedicles after reconstruction of axial images according to Laine et al. The comparison of the calculated accuracy rate of pedicle screw placement using virtual fluoroscopy with reported results achieved with CT-based navigation shows similar results for virtual fluoroscopy and a remarkable increase of accuracy in comparison to reports on conventional pedicle screw placement.     

三叠转盘卡在颈椎椎弓根内固定术中的临床应用

目的探讨自创二三叠转盘卡在颈椎骨折脱位椎弓根内固定术的临床应用效果。方法2007年1月至2012年12月,基于国人颈椎解剖生理及影像学数据,自创三叠转盘卡。采用转盘卡定位对66例颈椎骨折脱位伴2节段以上脊髓损伤的患者实行颈椎侧块螺钉联合椎弓根螺钉治疗,其中男40例,女26例;年龄19—77岁,平均45岁。均行颈椎CT、MRI检查,颈髓损伤2节段36例,颈髓损伤2节段以上30例。损伤类型：32例一侧关节突骨折伴脱位,16例双侧关节突骨折伴脱位,18例椎板骨折脱位。脊髓功能评价：依据Frankel分级标准,A级19例,B级16例,C级16例,D级15例;人院平均JOA评分5．92分。结果术后随访3—24个月,平均13．5个月。术后颈椎完全复位65例,复位不完全1例。依据术前、术后JOA评分结果,术后改善率平均为62％;术后Frankel分级平均提高1级以上;椎弓根螺钉植人准确度为97．2％。结论颈椎椎弓根三叠转盘卡,在术中应用准确、安全、便捷,置钉准确率高,有利于患者脊髓神经功能的恢复,对颈椎椎弓根螺钉的置钉有较好的指导作用,为临床治疗提供了一种实用工具。     

Computer-assisted pedicle screw placement for thoracolumbar spine fracture with separate spinal reference clamp placement and registration

BACKGROUND: The objective of the study was to improve the accuracy of computer-assisted pedicle screw installation in the spine. This study evaluates the accuracy of computer-assisted pedicle screw placement with separate spinal reference clamp placement and registration on each instrumented vertebra for thoracolumbar spine fractures. METHODS: Postoperative radiographs and CT scans assessed the accuracy of pedicle screw placement in 21 adult patients on each instrumented vertebra. Screw placements were graded as good if the screws were placed in the central core of the pedicle and the cancellous portion of the body. Screw placements were graded as fair if the screws were placed slightly eccentrically, causing erosion of the pedicular cortex, and with less than a 2-mm perforation of the pedicular cortex. Screw placements were graded as poor if screws were placed eccentrically with a large portion of the screw extending outside the cortical margin of the pedicle and with more than a 2-mm perforation of the pedicular cortex. RESULTS: A total of 140 image-guided pedicle screws were placed in 21 patients: 78 in the thoracic and 62 in the lumbar spine. Of the 140 pedicle screw placements, 96.4% (135/140) were categorized as good; 3.6% (5/140), fair; and 0% were poor. All 5 fair placement screws were placed in the thoracic spine without any mobility. CONCLUSION: Separate registration increases accuracy of screw placement in thoracolumbar pedicle instrumentation. Separate spinal reference clamp placement in the instrumented vertebra provides real-time virtual imaging that decreases the possibility of downward displacement during manual installation of the screw.     

Accuracy of single-time, multilevel registration in image-guided spinal surgery.

BACKGROUND CONTEXT: Computerized frameless stereotactic image-guidance has been used in recent years to improve the accuracy and safety of pedicle screw placement during spine surgery. Because the possibility of intervertebral motion exists, and because the patient is usually in a different position when preoperative imaging is performed compared with the operative position, it has been suggested that the imaging model of the complete lumbar spine and the surgically exposed lumbar spine may be significantly discordant. Consequently, current protocols suggest registering each spinal level (single-level registration) separately before pedicle screw placement at that level, a time-consuming process. PURPOSE: To assess the accuracy of single-time multilevel registration for multilevel pedicle screw placement during image-guided, computer-assisted spine surgery, in the setting of degenerative disorders of the lumbar spine. STUDY DESIGN/SETTING: This is a prospective clinical and radiological study of 45 patients with degenerative disorders of the lumbar spine who underwent instrumented fusion with the use of single-time multilevel registration computer-assisted, image-guided tomography. The accuracy of the pedicle screws placement was confirmed on the basis of a protocol that included intraoperative spontaneous electromyographic (EMG) recordings, direct pedicle visualization, and computer tomography (CT) scans when clinically indicated during the follow-up period. PATIENT SAMPLE: Forty-five consecutive patients who fulfilled the criteria of computer-assisted, image-guided tomography pedicle screw placement for degenerative lumbar spine disease without overt instability. OUTCOME MEASURES: The principal outcome measure was the accuracy of pedicle screw placement with single-time multilevel registration for multilevel pedicle screw placement during image-guided, computer-assisted spine surgery; postoperative CT performed for clinical indications during the follow-up course was used for the assessment of pedicle screw placement. METHODS: Patients were assessed clinically before and after the operation. Data from 45 consecutive cases of image-guided, computer-assisted lumbar spinal fusion were statistically analyzed to determine the relationship between the number of levels registered during single-time registry and the mean registration error (MRE). Intraoperative spontaneous EMG, direct visualization, and postoperative CT scans were used to assess the accuracy of pedicle screw insertion. RESULTS: None of the patients involved in this study experienced clinical sequelae of improper pedicle screw placement. MREs after surface mapping and after point merge were small (less than 1.00 mm and less than 3.00 mm, respectively). During the intraoperative assessment of the pedicle screws placement, no significant spontaneous EMG activity was recorded and the pedicular walls were found intact in direct visualization. The postoperative CT scans showed in 10 patients accurate placement in 55 of the 57 pedicle screws with expansion of the medial wall in two screws. CONCLUSIONS: Single-time, multilevel registration may decrease operative time relative to repeated, single-level registrations, without compromising the increased accuracy of pedicle screw placement afforded by this technique in the setting of degenerative disorders of the lumbar spine. Despite the advantages in computer-guided image surgery, cautious application in the individual patient is recommended until more comprehensive data can be gathered in specific degenerative pathology with overt instability; thus the knowledge of the anatomy remains crucial.     

经椎间孔椎体间植骨融合结合伤椎椎弓根螺钉内固定治疗严重胸腰椎骨折

目的 探讨经椎间孔椎体间植骨融合结合伤椎椎弓根螺钉内固定治疗严重胸腰椎骨折的临床疗效.方法 对15例严重胸腰椎骨折患者经椎间孔椎体间植骨、伤椎椎弓根螺钉内固定治疗,术后进行临床和影像学随访.结果 15例均获得随访,时间6～12个月.患者骨折椎体高度均明显恢复,伤椎椎体高度比:术前为49.2%±15.7%,术后3 d及3个月分别为99.2%±4.5%、91.1%±5.8%,与术前比较差异均有统计学意义(P＜0.05).Cobb角:术前为32.3°±9.6°,术后3 d和术后3个月分别为3.5°±3.4°、3.9°±3.7°,与术前比较差异均有统计学意义(P＜0.05).神经功能按ASIA分级,除5例A级患者无恢复外,其余较术前均有1级或1级以上的恢复.结论 经椎间孔椎体间植骨融合结合伤椎椎弓根螺钉内固定是治疗严重胸腰椎骨折的良好方法.