X线分步监测胸腰椎椎弓根螺钉植入的实验研究

[目的]探讨X线分步监测胸腰椎椎弓根螺钉准确置入的可行性。[方法]选8具T9～L5脊柱标本，随机分A、B两组，每组4具。A组按X线分步监测方法置入椎弓根螺钉。CT扫描测量椎弓根一半长、全长及螺钉通道长度和椎弓根e角及f角。当导针进至深度为椎弓根一半时，标准正位片导针远端到达椎弓根投影中线为符合标准；当导针进至深度为椎弓根全长时，腰椎到达椎弓根投影3／4处为符合标准，而胸椎到达椎弓根投影的1／2与3／4的中线处为符合标准；导针进入椎体，调整X线机臂，侧位片观察导针深度及f角。按照导针轨道植入椎弓根螺钉。B组为对照组，按传统X线监测方法置入椎弓根螺钉。通过观察两组螺钉的位置，评估A组方法的准确性。[结果]A组植入螺钉72枚：68枚位于椎弓根内，左右螺钉基本对称；4枚穿破椎弓根，穿破率为5．56％。B组亦为72枚：53枚位于椎弓根内；19枚穿破椎弓根，穿破率为26．38％。A组优于B组（P〈0．001）。[结论]X线分步监测胸腰椎椎弓根螺钉的置入，可克服传统X线平片的局限性及减少置钉过程中的人为因素干扰，在一定程度上可使两侧椎弓根螺钉对称植入，提高了螺钉置入的准确性。     

C型臂X线透视判断上中胸椎椎弓根螺钉位置的可靠性研究

目的：探讨C型臂X线透视判断上中胸椎椎弓根螺钉置入位置的准确性。方法：选用10具成年防腐保存的脊柱标本（T1～T6），根据椎弓根水平面倾斜角用手锥建立螺钉位置偏内（38个）、偏外（36个）、居中（46个）3种模型，分别置入导针和椎弓根螺钉后依次透视正位、侧位、椎弓根轴位、导针轴位、椎弓根螺钉轴位，根据导针和椎弓根钉与椎弓根投影的相互位置关系判断导针和椎弓根钉位置．同时行CT扫描观察椎弓根螺钉位置以及椎弓根内外侧皮质穿透情况．根据CT扫描结果判断C型臂X线图像对椎弓根螺钉置入监测的准确率。结果：120个椎弓根正位透视10枚偏内，其中5枚实际位置良好．未发现偏外者．正确率为35％；侧位透视不能判断偏内及偏外错误；椎弓根轴位透视将5枚居中判为偏内，准确率为95．9％；导针和椎弓根钉轴位透视均将4枚偏外模型判为居中,准确率为96．7％。结论：C型臂X线透视时椎弓根轴位和导针轴位图像能较准确判断椎弓根钉导针位置。     

下颈椎前路椎弓根螺钉固定系统的设计与运用

目的：研究下颈椎前路椎弓根螺钉钢板系统运用的可行性,为临床使用提供依据。方法：对16具颈椎标本随机分割获得C3．4,C4加C5．6,C6,7各8个运动单元（functionalspinalunit,FSu）,共32个FSU。运用下颈椎前路椎弓根螺钉钢板系统模拟植入重建FSU稳定性。测量钢板螺钉与椎体之间的适应性,运用X线摄片及CT扫描及重建评估下颈椎前路椎弓根螺钉植入的准确性,对于穿破椎弓根的标本,解剖明确其累及周围组织的情况。结果：32个FSU共计植入下颈椎前路椎弓根螺钉64枚,所有螺钉均顺利植入,无术中植入困难者。螺钉植入后与钢板螺钉孔之间的匹配程度好,未见难以锁紧的情况。钢板与椎体之间适应性良好。X线片提示所有64枚下颈椎前路椎弓根螺钉植入位置满意,螺钉长短合适。CT横断位像提示共有6枚螺钉在下颈椎椎弓根穿出,2枚内侧皮质1度穿破,4枚1度外侧缘皮质穿破累及横突孔内侧缘,未见螺钉≥2度穿破椎弓根。2枚下颈椎前路椎弓根内侧皮质1度穿破的患者,解剖发现仅有椎管内椎弓根内侧的静脉丛累及,未见硬膜囊受压,未见神经根受累。4枚1度外侧缘穿破的患者有1枚横突孔内椎静脉的累及,未见椎动脉穿破累及的情况,但其中1枚螺钉紧换椎动脉而行。结论：下颈椎前路椎弓根螺钉钢板系统适应下颈椎前路椎弓根螺钉固定重建,有临床运用价值。     

与术后CT比较评估术中运用C型臂X线机透视对34例腰椎侧凸的椎弓根固定的置钉情况

目的 探索一种有效方法来识别术中C型臂X线机监测腰椎侧凸椎弓根螺钉的误置.方法 在34例腰椎侧凸畸形的患者中共植入264枚椎弓根螺钉,所有病例手术后均接受CT检查,相比较后总结出3项X线标准可判断术中螺钉的置入位置.结果 比较术后CT和术中X线透视结果发现有7枚螺钉穿破椎弓根内壁.9枚螺钉穿破椎弓根外壁.结论 腰椎侧凸的手术中采用3项X线透视监测标准可有效识别椎弓根螺钉可能发生的误置,并对其及时进行位置修正.     

颈椎椎弓根螺钉徒手植入技术临床研究

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：作者应用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。椎弓根螺钉植入要点为：①术前仔细观察颈椎的侧位和双斜位x线片,并予以CT扫描以评估螺钉进针点、进针方向以及螺钉的长度及直径：②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卜象限处骨皮质,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2．0cm～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;③安装完毕后,即用C掣臂作双斜位透视,无误后关闭切口。结果：从C3到C7,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(6．9％)螺钉穿破椎弓根外侧皮质,4枚(2,8％)钉穿破椎弓根上侧皮质,2枚(1．3％)钉穿破椎弓根卜侧皮质。随访未发现与螺钉置入穿破椎弓根皮质仃关的神经血管损伤问题。结论：本研究提示,在事先充分的埘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同定是安全查行。     

颈椎椎弓根螺钉内固定术中并发症及其对策

目的：探讨颈椎椎弓根螺钉固定技术常见并发症及其处理方法。方法：应用Axis内固定系统（美国枢法模公司）对69例颈椎病患者进行经后路椎弓根内固定术，术中清晰显露颈椎侧块和突间关节，用直径3．2mm高速球形磨钻去除侧块外上象限处骨皮质，然后用直径2．0mm的手锥沿椎弓根事先确定的方向轻轻钻入，使其自然置入，深约2．0～2．5cm。确定无误后，则安置Axis钛板和置入长度合适的椎弓根螺钉，完毕后用C形臂X线机作双斜位透视。结果：从C3到C7，术中植入椎弓根螺钉314枚，其中21枚钉初次置入后感觉松动，经校正后二次置入成功，17枚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，其余螺钉置钉一次成功，未出现并发症。术后检查有28枚螺钉穿出椎弓根，6枚螺钉穿破椎弓根上侧皮质，3枚螺钉穿破椎弓根下侧皮质，12枚螺钉穿破椎弓根外侧皮质，7枚螺钉穿破椎弓根内侧皮质。随访未发现与螺钉置入穿破椎弓根皮质相关的神经血管损伤问题。结论：手术前充分了解每个患者颈椎椎弓根影像学解剖结构，术中仔细按原则操作，正确处理则会明显减少术中及术后并发症的发生。     

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。     

胸椎椎弓根螺钉置入治疗胸椎骨折的准确性和安全性评价

目的探讨胸椎椎弓根螺钉置入技术治疗胸椎骨折的准确性和安全性。方法50例胸椎骨折患者术前均行脊柱标准俯卧位CT加密扫描,测量进针点、入钉点至椎体前缘的深度、进针角度和直径,根据测得数据确定椎弓根螺钉置入的深度和方向,术后再行脊柱X线片及CT加密扫描评价置钉的准确性和安全性。结果50例患者共置入240枚胸椎椎弓根螺钉,术后CT加密扫描和X线片观察到220枚（91．7％）螺钉完全在椎弓根皮质骨内;20枚（8．3％）螺钉发生错置,其中7枚（2．9％）螺钉偏外;5枚（2．1％）螺钉偏前外侧,有2枚（0．8％）螺钉靠近主动脉;3枚（1．3％）螺钉偏下;3枚（1．3％）螺钉直径过大导致椎弓根内壁膨胀内移;2枚（0．8％）螺钉误入椎管内。螺钉完全在椎弓根皮质内的百分比在不同的胸椎节段之间有显著性差异。结论术前CT扫描测量胸椎骨折患者椎弓根的有关数据可为术中准确置入螺钉提供重要参考依据。术中标准的X线透视指导和解剖标记定位是保证胸椎椎弓根螺钉准确置入的关键因素。术后CT加密扫描能准确地反映椎弓根螺钉位置偏差,并能反映椎弓根螺钉与相邻结构的位置和关系。螺钉发生错置多见于上胸椎。     

C型臂X线透视导航下腰椎椎弓根螺钉内固定手术

目的探讨C型臂X线透视电子计算机辅助导航下腰椎椎弓根螺钉内固定手术的优缺点。方法对16例腰椎管狭窄症患者进行全椎板减压,C型臂X线透视电子计算机辅助导航下行椎弓根螺钉内固定,横突间或小关节间隙植骨术。共置入76枚椎弓根螺钉,术后对所有病例行腰椎正侧位X线像检查,7例32枚螺钉行CT横断面扫描。从X线侧位像上判断螺钉与椎体骺板的成角,CT横断面判断螺钉的进钉位置与深度和螺钉与矢状面的角度。结果所有患者术后无明显神经根损害表现。X线侧位片上发现17枚螺钉与骺板不平行,形成6.3°±2.2°的成角,CT横断面发现32枚螺钉全部在椎弓根内,与椎弓根骨皮质最近距离平均1.7±0.6mm,钉尖距离前方骨皮质平均6.5±2.4mm。与矢状面成角7.2°～18.4°,但均未超出内外骨皮质。结论C型臂X线透视电子计算机辅助导航可提高螺钉置入准确率,明显减少操作者及患者的X线暴露。但只能获得二维图像,缺少横断面,不能准确指导进钉的深度和进钉与矢状面的角度。     

前后位X线影像在下颈椎前路椎弓根置钉中的指导意义

目的通过标本置钉探讨术中C型臂X线机前后位透视指导下颈椎前路椎弓根钉(LCATPS)置入技术的可行性及方法。方法取9具成人尸体颈椎标本(排除畸形、骨折、脱位、肿瘤等病变),剔除其周围软组织至清楚显露椎体前壁。按照测量结果,直视下置入导针,轴位透视位置满意。随后前后位透视导针在椎弓根中间和入口的位置,最后沿导针置入空心钉,术后行CT扫描评价置钉效果。结果共置入螺钉90个,术后CT扫描grade 1级72个(80.00%),grade 2级15个(16.67%),grade 3级3个(3.33%),位置可接受的(grade 1~2级)共87个(96.67%)。穿破椎弓根壁者(grade 2~3级)18个全部为外侧壁,左侧12个,右侧6个;其中C33个,C512个,C73个。在椎弓根入口处所有90枚导针全部位于椎弓根入口投影弧边缘;在椎弓根中间有72个(80.00%)位于钩突关节外侧斜坡中间,6个(6.67%)位于钩突关节外侧斜坡内侧,12个(13.33%)位于钩突关节外侧斜坡外侧(灵敏性0.828,特异性1.00),且与grade分级具有相关性(Spearman相关系数0.515,P0.001)。结论前后位X线影像上导针在椎弓根入口应位于椎弓根投影弧边缘,在椎弓根中间应位于钩突外侧斜坡投影中间,初步认为前后位X线影像可以指导LCATPS的置入。     

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。     

漏斗技术结合探针技术置入胸椎椎弓根螺钉在脊椎畸形矫形术中的应用

目的 探讨应用漏斗技术结合探针技术置入胸椎椎弓根螺钉在脊椎畸形矫形术中的实用性和安全性。方法 12例脊椎畸形患者接受了后路矫形固定术,在手术矫形过程中,胸椎椎弓根螺钉的置入均采用“漏斗技术结合探针技术”,记录术中和术后并发症;术后常规复查X线片和CT,记录穿出骨皮质螺钉数目及距离。结果 采用“漏斗技术结合探针技术”共置入胸椎椎弓根螺钉129枚,术后复查CT见129枚螺钉中2枚穿透椎弓根内侧壁,3枚螺钉穿破外侧壁;1枚螺钉穿透椎体前壁。Heary分级,其置钉准确性达96.12%。结论 在脊椎畸形矫形术中,应用“漏斗技术结合探针技术”置入胸椎椎弓根螺钉的方法是实用的、安全的。     

Accuracy of pedicle screw placement for upper and middle thoracic pathologies without coronal plane spinal deformity using conventional methods

There is a growing interest in the implantation of pedicle screws into the middle and upper thoracic spine. However, usage of the technique is still under debate for these levels because the pedicles in these regions are small and exhibit a high degree of inter- and intraspecimen variability. Twenty-four consecutive patients treated for upper and middle thoracic pathologies by pedicle screw instrumentation under biplanar or uniplanar fluoroscopy were evaluated retrospectively. The rate of screw misplacement on postoperative computerized tomography and complications caused by misplaced screws were determined. In 24 cases, a total of 113 upper-middle thoracic pedicle screws were inserted. Fifty-one of them were inserted between T2 and T5 with guidance of biplanar fluoroscopy, and 62 were inserted between T6 and T8 with uniplanar fluoroscopy. The rate of misplacement was 20.3% for 113 screws (27.4% for T2 to T5 screws, and 14.5% for 62 T6 to T8 screws). Four screws were incorrectly inserted which could have clinical significance (3.5%), and 1 of them required revision. The difference between the upper and middle thoracic screws was not statistically significant (P=0.089). Screw insertion with laminectomy did not cause significant difference in both upper and middle thoracic regions. Only 2 complications were seen because of screw insertion. Pedicle screw insertion with guidance of fluoroscopy may be a reliable and safe method for upper and middle thoracic pathologies.     

上胸椎椎弓根螺钉固定并发症的探讨

目的分析上胸椎椎弓根螺钉固定的并发症,总结其手术技巧和经验。方法回顾性分析2009年4月至2012年4月采用T1~4椎弓根螺钉技术治疗的各类上胸椎损伤68例(共384枚螺钉),上胸椎骨折/脱位45例,均行Ⅰ期后路切开复位内固定术;结核合并后凸畸形23例,均行前路病灶清除植骨融合内固定术+后路矫形术。所有患者结合术中胸椎椎弓根四壁探查、术后手术节段椎体X线片、CT扫描,观察螺钉在椎弓根内的位置、角度及与椎弓根壁的关系和距离。结果椎弓根壁损伤54枚(14.06%),其中外侧壁损伤39枚(10.16%),包括Ⅰ级损伤27枚(7.03%),Ⅱ级损伤12枚(3.12%);内侧壁损伤15枚,均为Ⅰ级损伤。无1枚螺钉损伤上下壁,无1枚螺钉同时损伤超过2个壁,无术中置钉失败,螺钉松动位移2枚,创伤患者Frankel分级无加重,非创伤患者脊髓功能JOA评分由术前的5.9分提高至术后的11.5分,未发现植骨不融合、假关节形成或节段不稳表现。结论上胸椎椎弓根螺钉固定的并发症发生率低,是相对安全的操作方法。术前详细分析影像学资料、熟悉局部解剖特点、掌握合理的置钉技术,可有效避免并发症的发生。     

Pedicle and transverse process screws of the upper thoracic spine. Biomechanical comparison of loads to failure

STUDY DESIGN: An In vitro biomechanical load-to-failure test. OBJECTIVES: To determine the comparative axial pullout strengths of pedicle screw versus transverse process screws in the upper thoracic spine (T1-T4), and to compare their failure loads with bone density as seen on computed tomography. SUMMARY OF THE BACKGROUND DATA: The morphology of the upper thoracic spine presents technical challenges for rigid segmental fixation. Though data are available for failure characteristics of cervical-lateral mass screws, analogous data are wanting in regard to screw fixation of the upper thoracic spine. METHODS: Ten fresh-frozen human spines (T1-T4) were quantitatively scanned using computed tomography to determine trabecular bone density at each level. The vertebrae were drilled and tapped for the insertion of a 3.5-mill meter-diameter cortical bone screw in either the pedicle or the transverse process position. A uniaxial load to failure was applied. RESULTS: The mean ultimate load to failure for the pedicle screws (658 N) was statistically greater than that of the transverse process screws (361 N; P < 0.001). The T1 pedicle screw sustained the highest load to failure (775 N). No significant difference was found between load to failure for the pedicle and transverse process screws at T1. A trend toward decreasing load to failure was seen for both screw positions with descending thoracic level. Neither pedicle dimensions nor screw working length correlated with load to failure. CONCLUSIONS: Upper thoracic pedicle screws have superior axial loading characteristics compared with bicortical transverse process screws, except at T1. Load behavior of either of these screws was not predictable based on anatomic parameters.     

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.     

In vivo accuracy of thoracic pedicle screws.

STUDY DESIGN: A retrospective observational study of 279 transpedicular thoracic screws using postoperative computed tomography (CT). OBJECTIVE: To determine the accuracy of transpedicular thoracic screws. SUMMARY OF BACKGROUND DATA: Previous studies have reported the importance of properly placed transpedicular thoracic screws. To our knowledge, the in vivo accuracy of pedicle screw placement throughout the entire thoracic spine by CT is unknown. METHODS: The accuracy of thoracic screw placement within the pedicle and vertebral body and the resultant transverse screw angle (TSA) were assessed by postoperative CT. Cortical perforations of the pedicle were graded in 2-mm increments. Screws were regionally grouped for analysis. RESULTS: Forty consecutive patients underwent instrumented posterior spinal fusion using 279 titanium thoracic pedicle screws of various diameters (4.5-6.5 mm). The regional distribution of the screws was 39 screws at T1-T4, 77 screws at T5-T8, and 163 screws at T9-T12. Fifty-seven percent of screws were totally confined within the pedicle. Although medial perforation of the pedicle wall occurred in 14% of screws, in <1% there was >2 mm of canal intrusion. Lateral pedicular perforation occurred in 68% of perforating screws and was significantly more common than medial perforation (P < 0.0005). Seventeen screws penetrated the anterior vertebral cortex by an average of 1.7 mm. Screws inserted between T1 and T4 had a decreased incidence of full containment within the pedicle (P < 0.0005) and vertebral body (P = 0.039) compared with T9-T12. The mean TSA for screws localized within the pedicle was 14.6 degrees and was significantly different from screws with either medial (mean 18.0 degrees ) or lateral (mean 11.5 degrees ) pedicle perforation (P < 0.0005). Anterior vertebral penetration was associated with a smaller mean TSA of 10.1 degrees (P = 0.01) and with lateral pedicle perforation (P < 0.0005). There were no neurologic or vascular complications. CONCLUSIONS: Ninety-nine percent of screws were fully contained or were inserted with either < or =2 mm of medial cortical perforation or an acceptable lateral breech using the "in-out-in" technique. Anterior cortical penetration occurred significantly more often with lateral pedicle perforation and with a smaller mean TSA. The incidence of fully contained screws was directly correlated with the region of instrumented thoracic spine.     

漏斗技术置入胸椎椎弓根螺钉准确性研究

目的：对漏斗技术和徒手技术在胸椎弓根螺钉置入中的准确性和安全性进行对比研究。方法：采用8具胸椎标本,男性5具,女性3具;年龄57-82岁,平均68岁。随机分为2组,每组4具,利用漏斗技术和徒手技术分别进行椎弓根螺钉置入,然后CT扫描判断置入是否成功,对两种方法的成功率和危险性穿破率进行统计学对比分析。结果：漏斗技术置入96枚螺钉中成功84枚,徒手技术置入96枚中成功73枚,两种方法成功率比较,差异有统计学意义（P〈0．05）。漏斗技术危险性穿破2枚,徒手技术危险性穿破9枚,两种方法危险性穿破率比较,差异有统计学意义（P〈0．05）。结论：“漏斗技术”具有简单、经济、安全和实用等优点,可以减少神经根和硬膜囊的损伤机会。     

三维重建技术在上胸椎和颈椎椎弓根螺钉植入的临床应用

目的通过应用三维重建技术辅助椎弓根螺钉的植入,评价其在上胸椎和颈椎置钉中的准确性和安全性。方法 2013年1月至2013年11月,对12例需要行上胸椎、颈椎椎弓根螺钉植入手术的患者术前通过Mimics三维重建图像设计进钉通道并获取相关参数,术中辅助植入上胸椎、颈椎椎弓根螺钉共50枚,术后CT扫描评价螺钉位置,记录有无与螺钉植入的相关并发症。结果通过Mimics三维重建植入的50枚椎弓根螺钉,47枚完全在椎弓根内,3枚穿破椎弓根壁,椎弓根穿破率为6%,植钉准确率为94%,所有穿破椎弓根壁的螺钉的穿出距离均小于2 mm,螺钉位置可接受率为100%。无一例出现螺钉植入有关的神经、血管损伤等并发症。结论 Mimics三维重建技术辅助上胸椎、颈椎椎弓根螺钉植入的置钉准确性高、安全,且明显缩短手术时间。     

Pullout strength of pedicle screws versus pedicle and laminar hooks in the thoracic spine

While the biomechanical properties of pedicle screws have proven to be superior in the lumbar spine, little is known concerning pullout strength of pedicle screws in comparison to hooks in the thoracic spine. In vitro biomechanical pullout testing was performed to evaluate the axial pullout strength of pedicle screws versus pedicle and laminar hooks in the thoracic spine with regard to surgical correction techniques in scoliosis. Nine human cadaveric thoracic spines were harvested and disarticulated. To simulate a typical posterior segmental scoliosis instrumentation, standard pedicle hooks were used between T4 and T8 and supralaminar hooks between T9 and T12 and tested against pedicle screws. The pedicle screws were loaded strictly longitudinal to their axis; the hooks were loaded perpendicular to the intended rod direction. In total, 90 pullout tests were performed. Average pullout strength of the pedicle screws was significantly higher than in the hook group (T4-T8: 531 N versus 321 N, T9-T12: 807 N versus 600 N, p < 0.05). Both screw diameter and the bone mineral density (BMD) had significant influence on the pullout strength in the screw group. For scoliosis correction, pedicle screws might be beneficial, especially for rigid thoracic curves, since they are significantly more resistant to axial pullout than both pedicle and laminar hooks.