个体化导航模板在胸椎椎弓根螺钉置入中的初步临床应用

目的:通过临床应用评价个体化导航模板辅助胸椎椎弓根螺钉置入的准确性和安全性。方法:2008年7月～2009年9月,对11例需要行胸椎椎弓根螺钉置入手术的患者(青少年特发性脊柱侧凸7例,先天性脊柱侧凸2例,胸椎结核后凸畸形1例,多发性胸椎骨折1例)术前根据CT三维重建图像利用计算机辅助设计及快速成型技术设计制作46个胸椎个体化导航模板,术中应用个体化导航模板辅助在T2～T12置入椎弓根螺钉92枚,术后CT扫描评价螺钉位置,记录有无与螺钉置入相关的并发症。结果:通过个体化导航模板辅助置入的92枚胸椎椎弓根螺钉中,83枚完全在椎弓根内,9枚穿破椎弓根壁(其中椎弓根内侧壁穿破2枚、椎弓根外侧壁穿破7枚),其中5枚螺钉因椎弓根宽度小于4mm(3.0～3.8mm)而采用椎弓根旁固定方法(椎弓根螺钉轻度穿破椎弓根外侧壁经胸肋关节内侧进入椎体),椎弓根壁非故意穿破率为4.3%,置钉准确率为95.7%,所有穿破椎弓根壁的螺钉的穿出距离均小于2mm,螺钉位置可接受率为100%。无与螺钉置入有关的神经、血管、内脏损伤等并发症的发生。结论:个体化导航模板辅助胸椎椎弓根螺钉置入的置钉准确率高,安全、可行。     

对徒手置入胸椎椎弓根螺钉的安全性评价

目的：评价徒手置入胸椎椎弓根螺钉的安全性并探讨其置钉方法.方法：372例患者采用徒手方法置入胸椎椎弓根螺钉,记录置入操作中和术后并发症,其中37例患者术后行CT断层扫描检查判断螺钉的位置,记录所有穿透骨皮质螺钉的数目和距离.结果：共徒手置入胸椎椎弓根螺钉2261枚,平均每例患者置入螺钉6.08枚,术中6例次置钉过程中出现脑脊液从钉道中流出,术中和术后未出现神经、血管和内脏损伤等并发症.37例患者术后行CT扫描判断螺钉位置,405枚螺钉中124枚（30.62%）穿透骨皮质,1枚（0.02%）穿透椎弓根内侧壁超过4mm.结论：徒手置入胸椎椎弓根螺钉穿透骨皮质的发生率较高,应该根据每个椎体旋转、倾斜等差异个体化确定置钉位置和方向,操作仔细认真,保证准确、安全、可靠地置入胸椎椎弓根螺钉.     

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。     

快速成型个体化导航模板辅助胸椎椎弓根螺钉置入可行性研究

[目的]通过尸体标本实验的方法探讨个体化导航模板辅助胸椎椎弓根螺钉置入的准确性及可行性.[方法]对6具胸椎尸体标本进行CT扫描,根据CT扫描资料,利用逆向工程原理及快速成型技术设计制造出个体化导航模板,利用个体化导航模板在尸体标本上辅助置入胸椎椎弓根螺钉,所有螺钉的置入由同一位具有腰椎椎弓根螺钉置钉经验但无胸椎椎弓根螺钉置钉经验的骨科医师进行操作,随后采用大体解剖的方法肉眼观察置钉的准确性;并根据螺钉是否穿破椎弓根、穿出距离及穿破方向进行分级.[结果]共设计制作了72个个体化导航模板辅助置入胸椎椎弓根螺钉144枚,132枚(91.7%)螺钉完全在椎弓根内;12(8.3%)枚螺钉穿破椎弓根,其中2枚螺钉穿破椎弓根内侧壁(穿破距离分别为0.6、0.8 mm),10枚螺钉穿破椎弓根外侧壁(9枚螺钉穿出距离<2 mm,1枚螺钉穿出距离为2.5 mm);没有椎弓根上方、下方及椎体前方穿破的螺钉.所有穿破椎弓根壁的螺钉均在安全可接受的范围内.[结论]快速成型个体化导航模板辅助胸椎椎弓根螺钉置入准确率高,对术者无特别的经验要求,手术操作简单、安全,可避免术中放射性损伤,为胸椎椎弓根螺钉的置入提供了一种新的可行方法,尤其适用于初学者.     

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。     

颈椎椎弓根螺钉误置的临床特征分析

目的:观察颈椎椎弓根置钉的准确性,分析螺钉误置的临床特征。方法:32例施行颈椎椎弓根置钉手术患者,男22例,女10例;年龄25~74岁(51.5±13.6岁)。颈椎骨折/脱位16例,颈椎后纵韧带骨化8例,颈椎多节段椎间盘突出1例,颈椎管内肿瘤7例(神经鞘瘤3例,脊膜瘤3例,室管膜瘤1例)。术前进行颈椎CT三维重建,确定椎弓根螺钉的进钉点,并测量椎弓根的内倾角、矢状面角度及直径、长度等参数;术中在C型臂X线机透视辅助下置入椎弓根螺钉;术后复查颈椎CT观察椎弓根螺钉位置,按照Lee等的方法判断椎弓根螺钉位置准确性:0级,螺钉未穿破椎弓根;1级,螺钉穿破椎弓根25%的螺钉直径;2级,螺钉穿破椎弓根25%,但50%的螺钉直径;3级,螺钉穿破椎弓根50%的螺钉直径。2级和3级判为螺钉误置,分析椎弓根螺钉误置的特点;观察血管神经损伤等并发症情况。结果:32例患者中因术中置钉困难更改为侧块螺钉3枚,改为寰椎椎板钩1枚,共置入颈椎椎弓根螺钉147枚(上颈椎40枚,中下颈椎107枚),椎弓根螺钉位置0级53枚,1级67枚,2级17枚(上颈椎2枚,下颈椎15枚),3级10枚(上颈椎1枚,下颈椎9枚)。椎弓根螺钉总误置率为18.3%(2级+3级);外侧壁穿破17枚,下壁5枚,上壁4枚,内侧壁1枚。上颈椎椎弓根螺钉的误置率(7.5%)显著低于中下颈椎(22.4%)(P0.05);椎弓根外侧壁穿破率(11.5%)高于上壁(2.7%)、下壁(3.4%,)及内侧壁(0.7%)(P均0.01)。5例患者6枚螺钉术中椎弓根钉道攻丝后活动性出血,予骨蜡封堵及置入螺钉后即止血,无血肿或脑缺血梗死并发症。3例患者术后出现上肢神经根刺激症状,予颈椎制动、神经营养治疗,分别于术后1个月、3个月、4个月好转。结论:颈椎椎弓根螺钉误置率较高,但相关并发症较少;穿破椎弓根外侧壁多于内侧壁、上壁或下壁;中下颈椎椎弓根螺钉的误置率高于上颈椎。     

漏斗技术结合徒手椎弓根探针技术在椎弓根置钉术中的应用

目的探讨利用漏斗技术结合徒手椎弓根探针技术置入椎弓根钉的安全性及准确性。方法术前测量目标椎的e角、f角及椎弓根直径,选择准确的进针点:骶椎以下关节突左7点右5点为进针点,腰椎以人字嵴顶点作为进针点,胸椎按Kim推荐的入点进针。在椎弓根入口去皮质后据e、f角徒手推进椎弓根探针至椎体前缘,测量所需螺钉长度,再沿钉道扩孔、攻丝及置入相应直径与长度的螺钉;术后CT片按照椎弓根内侧壁穿透<2 mm,外侧壁穿透<4 mm作为安全评价标准。回顾性分析自2009年6月~2012年1月利用该技术在184例中置入736枚椎弓根钉的情况。结果所有螺钉椎弓根内侧壁穿透<2 mm,外侧壁穿透<4 mm,总合格率100%;无一例出现神经根或脊髓损伤加重的表现,无一例出现脑脊液漏。结论利用合理的进针点,在个体化置钉的基础上,利用漏斗技术结合徒手椎弓根探针技术能成功置入胸腰椎椎弓根钉。     

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.     

个体化选择脊柱侧凸患者胸椎椎弓根螺钉进钉点的研究

目的:探讨个体化选择脊柱侧凸患者胸椎椎弓根螺钉进钉点对置钉准确性的影响.方法:2006年3月至2008年6月手术治疗脊柱侧凸患者57例,其中青少年特发性脊柱侧凸44例,先天性脊柱侧凸12例,马凡综合征1例.根据患者术前CT设计拟固定胸椎的椎弓根螺钉进钉点并用于指导术中的进钉点选择,术后根据螺钉是否突破椎弓根的皮质壁来判断置钉准确性.结果:全部患者共置入椎弓根螺钉591枚,胸椎417枚,腰椎174枚,术后530枚螺钉的轴线完全位于椎弓根皮质内,准确率为89.7%, 其中胸椎置钉准确率为86.8%(362,417).61枚螺钉的轴线突破椎弓根皮质壁,胸椎55枚,腰椎6枚.55枚偏置的胸椎椎弓根螺钉中52枚螺钉的实际进钉点与术前设计一致,其中19枚钉尖位于椎体内;3枚螺钉为术中实际进钉点选择失误,螺钉轴线突破椎弓根皮质壁的距离均不超过4mm.无脊髓、大血管及脏器损伤等严重并发症发生.结论:个体化选择胸椎椎弓根螺钉进钉点可提高脊柱侧凸患者胸椎置钉的准确率,减少术中进钉点选择失误所致的并发症.     

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。     

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。     

Free-hand thoracic pedicle screws placed by neurosurgery residents: a CT analysis

Free-hand thoracic pedicle screw placement is becoming more prevalent within neurosurgery residency training programs. This technique implements anatomic landmarks and tactile palpation without fluoroscopy or navigation to place thoracic pedicle screws. Because this technique is performed by surgeons in training, we wished to analyze the rate at which these screws were properly placed by residents by retrospectively reviewing the accuracy of resident-placed free-hand thoracic pedicle screws using computed tomography imaging. A total of 268 resident-placed thoracic pedicle screws was analyzed using axial computed tomography by an independent attending neuroradiologist. Eighty-five percent of the screws were completely within the pedicle and that 15% of the screws violated the pedicle cortex. The majority of the breaches were lateral breaches between 2 and 4 mm (46%). There was no clinical evidence of neurovascular injury or injury to the esophagus. There were no re-operations for screw replacement. We concluded that under appropriate supervision, neurosurgery residents can safely place free-hand thoracic pedicle screws with an acceptable breach rate.     

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.     

徒手胸椎椎弓根螺钉置入技术治疗青少年特发性脊柱侧凸的安全性评价

目的 评价徒手胸椎椎弓根螺钉置入技术治疗青少年特发性脊柱侧凸的安全性。方法从2002年7月～2004年6月对38例青少年特发性脊柱侧凸患者，徒手应用胸椎椎弓根螺钉进行后路矫形内固定，所有患者术中进行神经电生理监测及X线透视确认，术后进行X线成像、CAT扫描评估螺钉位置，并对其中35例进行随访，从而评价本技术的安全性。结果共置入胸椎椎弓根螺钉326个，每一水平置入的螺钉数如下：T1,n=2；T2，n=10;T3，n=19；T4，n=27；L，n=28；T6，n=24；T7，n=23；TB，n=25；T9，n=29；T10,n=34；T11,n=48；T12，n=57。通过胸椎CT扫描评价326枚置入畸形胸椎的螺钉位置。共有19枚螺钉（5．8％）有中等程度的皮质穿破，即螺钉的中线在椎弓根壁皮质之外，其中6枚螺钉（1．8％）穿破椎弓根内侧壁。对35例患者进行术后跟踪随访，平均随访时间2年，未发现任何与置入的胸椎椎弓根螺钉（全部326枚螺钉）相关的神经、血管或内脏并发症。结论遵循严格步骤，逐步置入胸椎椎弓根螺钉的徒手技术在治疗青少年特发性脊柱侧凸中具有可靠的安全性。     

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.     

Thoracic pedicle screw placement guided by computed tomographic measurements.

Cadaveric pedicle screw placement guided by the measurements from axial computed tomography (CT) scans in the thoracic spine was assessed in this study. Axial CT scans were performed on four cadaveric thoracic spines, and the measurements included the pedicle transverse angle, inner pedicle width, and distance between the midline of the vertebra and the pedicle axis on the dorsal aspect of the lamina. With utilization of the data from CT scans, screws were directly placed into the thoracic pedicle from T1 to T10. Screw penetration of the pedicle was determined by gross examination. The results showed that the largest pedicle transverse angle was found at the levels of T1-2, and the smallest occurred at the T3 through T8 levels. The value of the pedicle inner width was quite different between specimens with a minimum of 3.0 mm at T4 and a maximum of 9.2 mm at T10. Gross examination of the pedicle showed that 13 (16.3%) of 80 screws penetrated the pedicle wall, with a Grade I penetration in 11 pedicles and a Grade II penetration in 2 pedicles. Screw penetration of the medial wall was found in four pedicles and penetration of the lateral wall was noted in nine pedicles. No screw penetration of the superior and inferior walls of the pedicle was identified in any of the four specimens. Thoracic pedicle screw placement guided by the measurements from axial CT scans significantly reduced the incidence of pedicle penetration. Axial CT measurements of the pedicle inner diameter and transverse angle as well as the starting point for screw insertion are recommended if pedicle screw fixation is intended in the thoracic spine.     

Computed tomographic evaluation of thoracic pedicle screw placement in idiopathic scoliosis

This retrospective observational study aimed to determine the accuracy of the placement of transpedicular thoracic screws used in idiopathic scoliosis and to evaluate the position and safety of the implants using postoperative computed tomography. Twenty-nine patients who underwent surgery for scoliosis between May 2003 and November 2005 were included in this study. The mean spinal curvature was 67°, and all of the patients had thoracic screws or hooks implanted. The positioning of 78 pedicle screws was evaluated using computed tomography after the free-handed technique was performed. The mean spinal curvature after surgery was 29°. Seventy-six percent of the screws were fully contained within the pedicle. Twenty-one screws breached the pedicle by between 2 and 4 mm (three medially and 18 laterally). Two screws were broken. A neurological deficit was identified in one case after surgery, but the deficit was reversed after the removal of the screws. This screw had a medial breach of greater than 4 mm. Most screws were inserted between the cortical vertebrae. Misplaced screws were most commonly inserted with a lateral cortical perforation.     

青少年脊柱侧凸患者胸椎椎弓根螺钉置入的准确性和安全性评价

目的：探讨青少年脊柱侧凸患者胸椎椎弓根螺钉置入的准确性和安全性，以减少相关手术并发症。方法：32例青少年脊柱侧凸患者术前均对畸形脊柱进行标准俯卧位CT加密扫描，测量进钉点至椎体前缘的深度、进针角度、椎弓根直径和椎体的旋转角度，根据测得数据确定椎弓根螺钉置入的深度和方向，置入螺钉后再行脊柱全长X线片及CT扫描评价置钉的准确性和安全性。结果：32例共置入226枚胸椎椎弓根螺钉，术后CT加密和X线片观察到205枚螺钉（90．7％）完全在椎弓根皮质骨内。10例21枚螺钉（9.3％）发生错置，7枚螺钉（3．1％）偏外，5枚螺钉（2．2％）偏前外侧（其中2枚螺钉靠近节段血管），4枚螺钉（1．8％）偏下，4枚螺钉（1．8％）直径过大导致椎弓根内壁膨胀内移，1枚螺钉（0．4％）误入椎管导致完全性脊髓损伤。T1～T4错置12枚（18．2％），T5～T12错置9枚（6．1％）；凸侧椎根螺钉置入的准确率为93．8％，凹侧为83．1％。结论：脊柱畸形患者术前应常规采用标准俯卧位CT加密扫描，根据扫描图像测得的相关数据可为术中准确置入椎弓根螺钉提供重要参考依据。在青少年脊柱侧凸患者胸椎椎弓根螺钉置入有一定的误置率，螺钉发生错置多见于上胸椎和凹侧．术中应高度重视。     

Accuracy and safety of thoracic pedicle screw placement in spinal deformities

OBJECTIVES: To determine the safety of pedicle screw fixation in thoracic spine deformity correction. METHODS: One hundred twelve pedicle screws were surgically placed in 25 patients with degenerative, posttraumatic, and Scheuermann kyphosis and idiopathic and neuromuscular scoliosis. Screw position was evaluated using intraoperative and postoperative radiographs and thin-slice computed tomography. RESULTS: Of the total 112 thoracic pedicle screws that were inserted, 98 screws (87.5%) were fully contained within the cortical boundaries of the pedicle. When comparing proximal screws (T1-T8) with distal screws (T9-T12) and convex placed screws with concave ones, a statistically significant difference in screw placement was evident (P < 0.05). More misplaced screws were seen proximally and on the concave side. Of the 14 malpositioned screws, 2 (1.8%) demonstrated aortic abutment. There were no neurologic deficits, vascular injuries, or mechanical failures recorded. CONCLUSIONS: Placement of thoracic pedicle screws is both feasible and safe.