胸腰椎椎弓根螺钉误置的原因分析及对策

目的 探讨胸腰椎椎弓根螺钉误置的原因及对策。方法 1996-2002年对293例脊柱疾病患者施行椎弓根螺钉内固定术发生的螺钉误置情况进行回顾性总结，分析。结果 293例共置入椎弓根螺钉1256枚，螺钉植入节段错误7例，占2.38%；上胸椎（T2-7）置钉113枚，有11枚螺钉穿破椎弓根皮质，占9.74%；下胸椎（T8-12）置钉261枚，有9枚螺钉穿破椎弓根皮质，占3.45%；腰骶椎置钉882枚，有16枚穿破椎弓根皮质，占1.81%，共计36枚螺钉，占2.87%；螺钉角异常65枚，占5.81%。结论 椎弓根螺钉误置与操作技术，解剖学变异及脊柱病损因素密切相关；良好的手术技巧，术前影像资料的认真观测及术中必要的影像监控是准确置钉的关键。     

改良二维X线导航模拟椎体三维影像引导胸腰段椎弓根钉内固定的临床应用

目的探讨改良二维X线导航模拟椎体三维影像的方式在引导胸腰段椎弓根钉内固定的应用效果。方法对66例胸腰段骨折和腰椎疾病患者行后路椎弓根钉固定撑开复位手术,采用改良二维导航的方法获取手术椎节的正侧位及斜位片,虚拟成椎体的正侧位及椎弓根轴位片,引导椎弓根钉植入术。结果术中共植入280枚椎弓根钉,导航虚拟路径与实际椎弓根钉影像之间的平均位置差为1.5mm,角度平均偏差1.0°。术后CT显示,全部椎弓根钉均位于椎弓根内,未出现涉及或突破皮质的现象;椎弓根钉与椎体纵轴角度平均偏差2.0°。结论采用改良二维X线导航模拟椎体三维影像的方法引导胸腰段椎弓根内固定,提高了置钉的准确性和安全性,简便可行,临床效果显著。     

CT三维重建立体导航引导技术在胸椎弓根钉置入手术中的应用

目的探讨术前CT三维重建立体导航引导技术在胸椎弓根钉置入手术中的应用方法和临床意义。方法2003年5月-2006年5月采用CT三维重建导航对2t例（122枚）胸椎弓根钉置入手术进行立体引导，其中上胸椎38枚，中下胸椎84枚。男13例，女8例；年龄为13—76岁，平均43岁。术中使用C形臂X线机拍摄正侧位X线片，术后行CT扫描以了解椎弓根钉位置情况。结果术后CT椎弓根位置扫描显示：A级109枚（89．3％）B级6枚（4．9％）；C级3枚（2．5％）；D级4枚（3．3％）。结论术前CT三维重建立体导航引导技术使椎弓根钉按预期的路径精确置入，尤其提高了具有挑战性的胸椎椎弓钉置入的安全性和准确性。     

导航引导椎弓钉加椎间钛笼稳定腰椎椎节的手术应用

目的:探讨导航技术在腰椎内植物手术中的应用.方法:对20例下腰椎节失稳手术,采用导航下的椎弓钉加后路椎间钛笼植入技术.共49个椎节,98枚椎弓钉,58个钛笼.内植完成后即作X线正侧位摄片与导航路径进行吻合测量;术后作CT椎弓根层面扫描.结果:内植物位置理想,进钉点均差2.2mm(最大3mm),角度均差3°(最大5°);Cage深度均差1.8mm(最大3.2mm),轴线角度均差2°(最大4°).CT椎弓钉位置评级:理想94枚(96%),4枚突破椎弓根外侧皮质(4%),Ⅱ级3枚,Ⅲ级1枚.结论:导航引导椎弓钉、椎间钛笼植入,只需1次X线成像就能做出虚拟的手术环境和路径;导航的瞬时追踪功能,使术者的手术工具做到实时监测,内植物达到精确制导,使操作形象、多维化,实时感强,是一种理想内植物引导模式.     

影像导航引导椎体成形术在治疗胸腰段椎体爆裂骨折中的应用

目的 探讨影像导航系统引导椎体成形术辅助短节段椎弓钉内固定在治疗胸腰段椎体爆裂骨折中的有效性和效果.方法 对28例胸腰段椎体爆裂骨折采用导航引导下的短节段椎弓钉固定结合钙磷骨水泥灌注椎体成形术,内植完成后即行X线片正侧位摄片与导航路径进行吻合测量.结果 本组患者术后内植物位置理想,椎弓钉位置评级:理想106枚(94.5%),6枚突破椎弓根外侧皮质(5%),Ⅱ级2枚.术后1周离床负重行走.椎体高度丢失恢复40%,随访12个月后显示椎体高度平均改变0.2%,过伸过屈动力摄片显示固定段无异常活动,未发现有椎弓钉松动、断裂病例.结论 导航引导椎弓钉植入及钙磷骨水泥灌注椎体成形术,只需1次X线片成像就能做出虚拟的手术环境和路径;使内植物精确植入最佳位置,提高了椎弓钉植入及椎体成形手术的安全性,提高手术疗效.     

实时导航在治疗胸腰段骨折中的临床应用价值

目的探讨实时导航在椎弓根螺钉治疗胸腰段骨折术中置钉的应用价值。方法对我院2001年3月至2006年12月收治的86例患者进行回顾性研究,其中实时导航下手术46例（A组）;传统X线透视法手术40例（B组）。通过术中影像、术后椎弓根层面CT扫描、手术时间及出血量,对两组进行分析。结果 A组198枚椎弓根钉,全部螺钉均位于椎弓根内,置钉准确率100%;B组182枚椎弓根钉,176枚位于椎弓根内,6枚突破皮质,置钉准确率96.7%,两组均未造成神经血管并发症。A、B两组平均手术时间分别为（128±38）ml、（158±42）ml,出血量分别为（307±60）ml、（412±82）ml,两者比较差异有统计学意义（P〈0.05）。结论实时导航下椎弓根钉内固定治疗胸腰段骨折,具有置钉准确率高,手术时间短等优点,是一项安全的手术技术。     

O型臂导航系统辅助胸椎椎弓根螺钉置入的准确性及学习曲线

【摘要】 目的：探究应用O型臂导航系统辅助胸椎椎弓根螺钉置入的准确性及其学习曲线。方法：回顾性分析2015年5月~2018年5月我院行胸椎内固定手术的患者临床资料109例,其中男性49例,女性60例,年龄53.5±12.3岁（27～77岁）。根据是否使用O型臂导航系统辅助置钉分为导航组（A组,n=66）和非导航组（B组,n=43）,置钉过程由医师1（具有3年脊柱外科手术经验）或医师2（具有20年脊柱外科手术经验）完成。导航组医师1完成35例（A1组）,医师2完成31例（A2组）;非导航组医师1完成18例（B1组）,医师2完成25例（B2组）。待引流管拔除后复查胸椎平扫CT,根据Neo′s法对术后椎弓根螺钉位置进行分级,统计各组的满意置钉（0级、1级螺钉）和螺钉穿透皮质（1级、2级、3级螺钉）的情况。比较各组的满意置钉率和皮质穿透率,并用皮质穿透率衡量同组内不同节段的置钉准确度。记录并比较各组的置钉时间,观察置钉时间随手术例数增加的动态变化,采用线性回归分析的方法探讨置钉时间与手术例数的关系。比较每组内不同阶段置钉时间和皮质穿透率的差异,评价术中应用O型臂导航系统的学习曲线。结果：共置入胸椎椎弓根螺钉668枚,其中,A1组置入螺钉222枚,满意置钉率97.3%,皮质穿透率10.8%;A2组置入螺钉188枚,满意置钉率97.9%,皮质穿透率10.1%;B1组置入螺钉120枚,满意置钉率91.7%;皮质穿透率20.0%;B2组置入螺钉138枚,满意置钉率97.8%,皮质穿透率9.4%。B1组的满意置钉率明显低于其他各组,且皮质穿透率也明显高于其他各组。B1组在胸椎不同节段（上胸段、中胸段、下胸段）的皮质穿透率存在显著差异（37.5%,28.6%,13.4%,P=0.02）,而其余3组在胸椎不同节段的置钉准确率无统计学差异。B1组的单枚螺钉置钉时间（4.87±0.34min）明显高于其他3组（4.38±0.97min、4.40±1.00min、4.18±0.22min）。导航组（A组）的单枚螺钉置钉时间随着术者手术例数的增加而下降,线性回归分析显示A1组单枚螺钉置钉时间与手术例数呈显著线性负相关（F=123.3,P＜0.001）,回归方程：置钉时间=5.88-0.084×手术例数,R2=0.79;A2组可得出相同结果（F=141.6,P＜0.001,置钉时间=6.01-0.10×手术例数,R2=0.83）。A1组的1~10例、11~20例、21~30例手术的皮质穿透率无统计学差异（P=0.97）;同样,A2组上述3个阶段的皮质穿透率也无显统计学差异（P=0.96）。结论：应用O型臂术中导航辅助胸椎椎弓根螺钉置入可以显著提高低年资医师的置钉准确率,增加手术安全性。随着手术例数增加O型臂导航下置钉时间显著下降;不同年资医师首次使用O型臂导航均能取得较高并且稳定的置钉准确度。     

影像导航椎体成形术治疗胸腰段椎体爆裂骨折

目的探讨骨科手术导航系统引导椎体成形术辅助短节段椎弓钉内固定治疗胸腰段椎体爆裂骨折应用的有效性和效果。方法对18例胸腰段椎体爆裂骨折采用导航引导下的短节段椎弓钉固定结合钙磷骨水泥灌注椎体成形术,内植完成后即做X线片正侧位摄片与导航路径进行吻合测量。结果本组患者术后内植物位置理想,椎弓钉位置评级理想68枚(94%),3枚突破椎弓根外侧皮质(4%),II级1枚。术后1周离床负重行走。椎体高度丢失恢复40%,随访12个月后显示椎体高度平均改变0.15%,过伸过屈动力摄片显示固定段无异常活动,未发现有椎弓钉松动、断裂病例。结论导航引导椎弓钉植入及钙磷骨水泥灌注椎体成形术,只需1次X线片成像就能做出虚拟的手术环境和路径;使内植物精确植入最佳位置,提高了椎弓钉植入及椎体成形手术的安全性,提高手术疗效。     

椎弓根螺钉在颈胸段骨折脱位中的临床运用

目的：评价椎弓根螺钉技术在颈胸段骨折脱位（C6-T2）中的运用价值。方法：2001年5月至2008年1月运用椎弓根螺钉植入技术治疗颈胸段骨折脱位患者26例,男17,女9例;年龄20-75岁,平均48．5岁。采用单纯后路椎弓根螺钉技术17例,后路椎弓根螺钉技术结合前路减压钢板内固定9例。术后3d运用CT平扫及重建片观察评价植入颈胸段椎弓根螺钉的准确性、螺钉植入相关并发症;随访观察患者颈胸段术后植骨融合情况;统计患者术前与术后6个月JOA评分及ASIA分级改善情况,综合评价患者脊髓及神经功能改善情况。结果：所有患者获得随访,随访时间3～74个月,平均36．5个月。4例完全性瘫痪患者术后6个月内死亡。共计植入椎弓根螺钉104枚,其中颈椎椎弓根74螺钉枚（其中：C516枚,C616枚,C742枚）,胸椎椎弓根螺钉30枚（其中：T1 22枚,T28枚）,所有椎弓根螺钉在术中均成功植入,无脊髓、神经根及椎动脉损伤。术后CT提示颈椎椎弓根螺钉11枚（14．9％）穿破椎弓根,其中7枚（9．5％）穿破外侧皮质,1枚（1．4％）穿破椎弓根上侧皮质,3枚（4．1％）穿破椎弓根下侧皮质。胸椎椎弓根螺钉中,3枚（10％）穿破胸椎椎弓根,其中2枚（6．7％）穿出椎弓根外侧缘,1枚（3．3％）穿破内侧缘（〈2mm）,但无临床症状。术后随访1枚C,椎弓根螺钉断裂,但患者无明显临床症状,其余无螺钉松动及断钉情况出现。所有患者固定良好,并均达到骨性融合。术后6个月患者平均JOA评分由术前（7．5±2．0）分恢复到（14．5±2．3）分,差异有统计学意义（t=6．34,P〈0．05）。ASIA分级情况,除3例完全性瘫痪患者脊髓功能术后无明显改善外,余患者术后脊髓神经功能均有不同程度恢复。结论：椎弓根螺钉在颈胸段骨折脱位治疗中安全、可靠。术者应熟练掌握颈胸段后?     

颈椎椎弓根螺钉徒手植入技术的临床研究

目的 评价颈椎椎弓根螺钉徒手植入技术（无须术中影像技术引导）的安全性和可靠性。方法应用Axis内固定系统（美国枢法模公司）对36例颈椎疾病患者进行颈后路经椎弓根内固定术,共植入螺钉144枚,方法如下：①术中清晰地显露颈椎侧块和突间关节,用直径3,0mm高速球形磨钻去除侧块外上象限处骨皮质,然后用2．0mm的自制手锥沿椎弓根事先确定的方向轻轻钻入,若遇阻力则需略改变方向,使其自然置入,深约2～2,5cm。确定无误后,则安置Axis钛板和置入长度合适的椎弓根螺钉。②安装完毕后,即用C型臂X线机作双斜位透视,无误后关闭切口。结果从G～G,共植入根弓根螺钉144枚,其中10枚（6．8％）钉初次置入后感觉松动,经校正后二次置入成功,11枚（3．5％）钉道钻孔后出血较多,但及时处理后出血停止并无不良结果。术后X线斜位片及CT片显示,16枚（11．1％）螺钉穿破椎弓根,其中10枚螺钉（6．9％）穿破椎弓根外侧皮质,4枚（2．8％）穿破椎弓根上侧皮质,2枚（1．3％）穿破椎弓根下侧皮质。随访未发现与螺钉置入穿破椎弓根皮质有关的神经血管损伤问题。结论本研究提示,在事先充分的对每个患者颈椎椎弓根X线及CT解剖结构了解的情况下,徒手置入椎弓根螺钉行颈椎后路内固定安全可行。     

X线透视与计算机导航系统引导颈椎椎弓根螺钉内固定技术的对比研究

目的对X线透视下和计算机导航系统引导下颈椎椎弓根螺钉内固定的精确性进行对比研究。方法X线透视引导下145枚和CT三维导航系统辅助下置入的159枚颈椎椎弓根螺钉,术后进行经椎弓根螺钉水平的CT平扫或术后c型臂透视3D重建,观察椎弓根螺钉置入的精确性。结果X线透视引导组螺钉置入满意率为91．7％,CT三维导航系统引导组螺钉置入满意率为97．5％,两组满意率有显著性差异（P〈0．05）。两组病例均未出现明显的神经血管损伤并发症。对其中20例病例进行了术中导航操作时间和导航精确性的监测,术中工具注册和参考点照合时间平均3．5min（2～8min）,位置误差率平均0．31mm（0．12～0．56mm）。每颗椎弓根螺钉定位针置入所需时间平均2min（1-3．5min）。术中只需进行两次C型臂透视印证螺钉定位针和螺钉置入的准确性。结论采用CT三维导航系统辅助,能显著提高椎弓根螺钉置入的精确性。     

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.     

Pedicle screw placement in the thoracic spine: a randomized comparison study of computer-assisted navigation and conventional techniques

Objective： To evaluate the accuracy of computer-assisted pedicle screw installation and its clinical benefit as compared with conventional pedicle screw installation techniques.
Methods： Total 176 thoracic pedicle screws placed in 42 thoracic fracture patients were involved in the study randomly, 20 patients under conventional fluoroscopic control （84 screws） and 22 patients had screw insertion under three dimensional （3D） computer-assisted navigation （92 screws）. The 2 groups were compared for accuracy of screw placement, time for screw insertion by postoperative thincut CT scans and statistical analysis by χ^2 test. The cortical perforations were then graded by 2-mm increments： Grade Ⅰ （good, no cortical perforation）, Grade Ⅱ （screw outside the pedicle 〈2 mm）, Grade Ⅲ （screw outside the pedicle 〉2 mm）.
Results： In computer assisted group, 88 （95.65%） were Grade Ⅰ （good）, 4 （4.35%） were Grade Ⅱ （〈2mm）, no Grade Ⅲ （〉2 mm） violations. In conventional group, there were 14 cortical violations （16.67%）, 70 （83.33%） were Grade Ⅰ （good）, Ⅱ （13.1%） were Grade Ⅱ （〈2 mm）, and 3 （3,57%） were Grade Ⅲ （〉2 mm） violations （P〈0.001）. The number （19.57%） of upper thoracic pedicle screws （ T1-T4 ） inserted under 3D computer-assisted navigation was significantly higher than that （3.57%） by conventional fluoroscopic control （P〈0.001）. Average screw insertion time in conventional group was （4.56 ±1.03） min and （2.54 ± 0.63） min in computer assisted group （P〈0.001）. In the conventional group, one patient had pleura injury and one had a minor dura violation.
Conclusions： This study provides further evidence that 3D computer-assisted navigation placement ofpedicle screws can increase accuracy, reduce surgical time, and be performed safely and effectively at all levels of the thoracic spine, particularly upper thoracic spine.     

Evaluation of a transpedicular drill guide for pedicle screw placement in the thoracic spine

Insertion of pedicle screws in the thoracic spine is technically difficult and may lead to major complications. Although many computer-assisted systems have been developed to optimize pedicle screw insertion, these systems are expensive, not user-friendly and involve significant radiation from pre-operative computed tomographic (CT) scan imaging. This study describes and evaluates a transpedicular drill guide (TDG) designed to assist in the proper placement of pedicle screws in the thoracic spine. Pilot holes were made manually using the TDG in the thoracic spine (T1-T11) of three human cadavers before inserting 4.5-mm-diameter screws. CT scans followed by visual inspection of the spines were performed to evaluate the position of the screws. Five of 66 screws (7.6%) violated the pedicle wall: two (3.0%) medially and three (4.5%) laterally. The medial and lateral perforations were within 1 mm and 2 mm of the pedicle wall, respectively. The medial perforations were not at risk of causing neurological complications. No screw penetrated the superior or inferior pedicle wall. The TDG is easy to use and can decrease the incidence of misplaced thoracic pedicle screws. The TDG could be used as a complement to fluoroscopy in certain applications, especially for training surgeons.     

Ultrasound-based navigated pedicle screw insertion without intraoperative radiation: feasibility study on porcine cadavers

BACKGROUNDNavigation systems for spinal fusion surgery rely on intraoperative computed tomography (CT) or fluoroscopy imaging. Both expose patient, surgeons and operating room staff to significant amounts of radiation. Alternative methods involving intraoperative ultrasound (iUS) imaging have recently shown promise for image-to-patient registration. Yet, the feasibility and safety of iUS navigation in spinal fusion have not been demonstrated.PURPOSETo evaluate the accuracy of pedicle screw insertion in lumbar and thoracolumbar spinal fusion using a fully automated iUS navigation system.STUDY DESIGNProspective porcine cadaver study.METHODSFive porcine cadavers were used to instrument the lumbar and thoracolumbar spine using posterior open surgery. During the procedure, iUS images were acquired and used to establish automatic registration between the anatomy and preoperative CT images. Navigation was performed with the preoperative CT using tracked instruments. The accuracy of the system was measured as the distance of manually collected points to the preoperative CT vertebral surface and compared against fiducial-based registration. A postoperative CT was acquired, and screw placements were manually verified. We report breach rates, as well as axial and sagittal screw deviations.RESULTSA total of 56 screws were inserted (5.50 mm diameter n=50, and 6.50 mm diameter n=6). Fifty-two screws were inserted safely without breach. Four screws (7.14%) presented a medial breach with an average deviation of 1.35±0.37 mm (all <2 mm). Two breaches were caused by 6.50 mm diameter screws, and two by 5.50 mm screws. For vertebrae instrumented with 5.50 mm screws, the average axial diameter of the pedicle was 9.29 mm leaving a 1.89 mm margin in the left and right pedicle. For vertebrae instrumented with 6.50 mm screws, the average axial diameter of the pedicle was 8.99 mm leaving a 1.24 mm error margin in the left and right pedicle. The average distance to the vertebral surface was 0.96 mm using iUS registration and 0.97 mm using fiducial-based registration.CONCLUSIONSWe successfully implanted all pedicle screws in the thoracolumbar spine using the ultrasound-based navigation system. All breaches recorded were minor (<2 mm) and the breach rate (7.14%) was comparable to existing literature. More investigation is needed to evaluate consistency, reproducibility, and performance in surgical context.CLINICAL SIGNIFICANCEIntraoperative US-based navigation is feasible and practical for pedicle screw insertion in a porcine model. It might be used as a low-cost and radiation-free alternative to intraoperative CT and fluoroscopy in the future.     

带预警装置椎弓根螺锥的临床应用

目的探讨带预警装置椎弓根螺锥在胸腰椎手术应用中的优越性。方法回顾性研究自2010年9月~2011年10月收治的需进行椎弓根钉系统内固定的胸腰椎疾病30例,其中腰椎间盘突出16例,胸腰椎骨折10例,椎体滑脱4例。在减压解除神经压迫或复位椎体的同时利用带预警装置椎弓根螺锥行椎弓根钉固定。结果共置入160枚螺钉,术中及术后X线片评估椎弓根钉置钉准确度为100%,术后三维影像评估螺钉位置准确率为94.4%,螺钉平均置入时间(4.5±0.7)min/枚,未出现螺钉置入相关的近期并发症。结论在胸腰椎手术中应用带预警装置椎弓根螺锥行椎弓根钉置入,可有效提高置钉的精确性、安全性,缩短手术时间、减少术中出血量及放射线的暴露强度。     

Comparative results between conventional and computer-assisted pedicle screw installation in the thoracic, lumbar, and sacral spine

STUDY DESIGN: A comparative study on the position of pedicle screws in patients treated surgically with and without computer assistance. OBJECTIVES: To evaluate the accuracy of computer-assisted pedicle screw installation, and to evaluate its clinical benefit as compared with conventional pedicle screw installation techniques. SUMMARY OF BACKGROUND DATA: In vitro and clinical studies have documented a significant rate of misplaced screws in the thoracolumbar area. Neurologic complications are recognized problems caused by screw misplacement. METHODS: Patients treated surgically with computer assistance were compared with a historical control group of patients treated surgically with conventional techniques in the same hospital and by the same surgical team. All screw positions were measured with a postoperative magnetic resonance tomography, and cortical effractions were categorized in 2-mm increments. Patients' charts also were reviewed to assess individual neurologic outcomes. RESULTS: The control cohort was composed of 100 patients, with 544 screws from T5 to S1. The computer-assisted cohort was composed of 50 patients, with 294 screws from T2 to S1. In the control cohort, 461 of 544 screws (85%) were found completely within their pedicles as compared with 278 of 294 screws (95%) correctly placed in the computer-assisted group (P < 0.0001). All 16 screws incorrectly placed with computer assistance were found 0.1 mm to 2 mm from the pedicle cortex. In the control cohort, 68 screws were found 0.1 mm to 2 mm, 10 screws 2.1 mm to 4 mm, and 5 screws more than 4 mm from the pedicle cortex. Seven patients in the control cohort were surgically retreated because of postoperative neurologic deficits, whereas no patients in the computer-assisted group were surgically retreated. CONCLUSIONS: Computer assistance can decrease the incidence of incorrectly positioned pedicle screws.     

Accuracy of pedicle screw insertion with and without computer assistance: a randomised controlled clinical study in 100 consecutive patients

We performed a randomised controlled study to assess the accuracy of computer-assisted pedicle screw insertion versus conventional screw placement under clinical conditions. One hundred patients scheduled for posterior thoracolumbar or lumbosacral pedicle screw instrumentation were randomised into two groups, either for conventional pedicle screw placement or computer-assisted screw application using an optoelectronic navigation system. From the computer-assisted group, nine patients were excluded: one because of an inadequate preoperative computed tomography study, seven because of problems with the specific instruments or the computer system, and one because of an intraoperative anesthesiological complication. Thus, there were 50 patients in the conventional group and 41 in the computer-assisted group, and the number of screws inserted was 277 and 219, respectively. There was no statistical difference between the groups concerning age, gender, diagnosis, type of operation performed, mean operating time, blood loss, or number of screws inserted. The time taken for screw insertion was significantly longer in the computer-assisted group. Postoperatively, screw positions were assessed by an independent radiologist using a sophisticated CT imaging protocol. The pedicle perforation rate was 13.4% in the conventional group and 4.6% in the computer-assisted group (P = 0.006). Pedicle perforations of more than 4 mm were found in 1.4% (4/277) of the screw insertions in the conventional group, and none in the computer-assisted group. Complications not related to pedicle screws were two L5 nerve root lesions, one end plate fracture, one major intraoperative bleeding and one postoperative death in the conventional group, and one deep infection in the computer-assisted group. In conclusion, pedicular screws were inserted more accurately with image-guided computer navigation than with conventional methods. Received: 11 October 1999 Revised: 2 February 2000 Accepted: 15 February 2000     

Genauigkeit der CT-basierten Navigation von Pedikelschrauben an der Brustwirbelsäule im Vergleich zur konventionellen Technik

The goal of this study was to evaluate the accuracy of CT-based computer-assisted pedicle screw insertion in the thoracic spine in patients with fractures, metastases, and spondylodiscitis compared to a conventional technique. A total of 324 pedicle screws were inserted in the thoracic spines of 85 patients: 211 screws were placed using a CT-based optoelectronic navigation system assisted by an image intensifier and 113 screws were placed with a conventional technique. Screw positions were evaluated with postoperative CT scans by an independent radiologist. In the computer-assisted group, 174 (82.5%) screws were found completely within their pedicles compared with 77 (68.1%) correctly placed screws in the conventional group ( p<0.003). Despite use of the navigation system, 1.9% of the computer-assisted screws perforated the pedicle wall by more than 4 mm. The additional use of the image intensifier helped to identify the correct vertebral body and avoided cranial or caudal pedicle wall perforations.     

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。