寰枢椎定位导向内固定置钉点、角度、直径及长度的个性化设计

目的：为提高内固定置钉的一次成功率，利用辅助检查资料为寰枢椎椎弓根螺钉的置钉制定简单、实用的个性化方案。 方法：选择2002-01/2006-09解放军第二五一医院骨科患者31例。术中采用自制的寰枢椎定位导向器，根据寰枢椎椎弓根X射线-CT个体化测量的结果，确定进钉点、入钉的角度，选择直径及长度合适的椎弓根螺钉置入。寰椎椎弓根进钉点：左侧（19.93±1.32）mm，右侧（19.16±1.30）mm，寰椎椎弓根向内侧进钉角度：左侧（23.72±2.09）°，右侧（23.35±1.91）°，寰椎向头侧进钉角度（9.00±1.20）°。枢椎椎弓根进钉点：左侧（13.14±0.82）mm，右侧（13.85±0.79）mm。 枢椎椎弓根向内侧进钉角度：左侧（24.52±1.26）°右侧（20.42±1.42）°，枢椎向头侧进钉角度（25.00±3.00）°。 结果：①对31例患者置入124枚椎弓根螺钉，1次置钉成功122枚螺钉，正确率为98.39%，有2枚因内倾角偏差不够，穿破椎弓根的外侧骨皮质而改为2次定位。②2例术后出现枕大神经痛，经对症治疗1个月后痊愈，2例螺钉穿破寰椎左侧椎弓根外侧壁，未发现脊髓、椎动脉损伤。③所有患者X射线片显示寰椎完全复位，枢椎齿状突骨折处对位良好。CT片示螺钉与椎动脉的脊髓位置关系良好。④平均随访10.5个月，均获得骨性融合，未发现钉板断裂材料反应。⑤按JOA评分标准，优16例，良12例，可2例，差1例，优良率90.32%。 结论：X射线-CT个性化设计方案可提高寰枢椎椎弓根螺钉的置入成功率。     

经椎弓根钉板内固定治疗上颈椎疾患的个性化设计及临床应用

背景：上颈椎疾患从后路行椎弓根固定在国内个别大型医院虽已相继开展,但该手术仍为颈椎外科高难度手术。为了将手术风险降至最低,作者设计了一套个体化手术方案,并结合自行研制的椎弓根定位导向器行术中精确定位置钉,经检索相关数据库在国内未见报道。 目的：提高内固定置钉的一次成功率及植入体的生物力学效应,利用辅助检查资料为寰枢椎椎弓根螺钉的置钉制定简单、实用的个性化方案。 方法：选择2002-01/2006-09解放军第二五一医院骨科患者31例。术中采用自制的寰枢椎定位导向器,根据寰枢椎椎弓根X射线-CT个体化测量的结果,确定进钉点、入钉的角度,选择直径及长度合适的椎弓根螺钉置入。寰椎椎弓根进钉点：左侧(19.93± 1.32) mm,右侧(19.16±1.30) mm,寰椎椎弓根向内侧进钉角度：左侧(23.72±2.09)°,右侧(23.35±1.91)°,寰椎向头侧进钉角度(9.00±1.20)°。枢椎椎弓根进钉点：左侧(13.14±0.82) mm,右侧(13.85±0.79) mm。 枢椎椎弓根向内侧进钉角度：左侧(24.52±1.26)°,右侧(20.42±1.42)°,枢椎向头侧进钉角度(25.00±3.00)°。 结果与结论：①31例患者置入124枚椎弓根螺钉,1次置钉成功122枚螺钉,正确率为98.39%,有2枚因内倾角偏差不够,穿破椎弓根的外侧骨皮质而改为2次定位。②2例术后出现枕大神经痛,经对症治疗1个月后痊愈,2例螺钉穿破寰椎左侧椎弓根外侧壁,未发现脊髓、椎动脉损伤。③所有患者X射线平片显示寰椎完全复位,枢椎齿状突骨折处对位良好。CT片示螺钉与椎动脉的脊髓位置关系良好。④平均随访10.5个月,均获得骨性融合,未发现钉板断裂材料反应。无炎症、排异等宿主反应。⑤按JOA评分标准,优16例,良12例,可2例,差1例,优良率90%。提示从生物力学角度实施植入体置入,可提高寰枢椎椎弓根螺钉的置入成功率。     

不同外倾角脊柱椎弓根螺钉置入机体后的内固定效果：生物力学评价

背景：有研究表明，影响椎弓根螺钉置入机体后固定效果的因素有螺钉的结构形态、螺纹参数、骨密度，手术时螺钉拧紧力矩大小，以及进钉的深度等。脊柱椎弓根螺钉并横向牵引装置的把持力与外倾角是否也有一定关系？ 目的：观察不同外倾角对椎弓根螺钉并横向牵引装置的把持力的影响。 设计：重复测量实验。 单位：南京医科大学第一附属医院骨关节中心。 对象：实验于2003-06/11在河海大学材料力学实验室完成，选择18只成人干燥腰椎（L1~5节段）椎体标本，标本均为南京医科大学解剖学教研室提供，实验经过医院伦理委员会批准。实验用椎弓根螺钉为不锈钢材料，直径5.5 mm，螺纹参数相同，钉长150 mm，其中螺纹部分长50 mm。EW型电子万能材料实验机为河海大学材料力学实验室提供。 方法：用单光子骨密度测定仪测定骨密度后按骨密度编号，完全随机法将椎体分为外倾角5°组、外倾角15°组及外倾角30°组，每组6只。① 椎弓根螺钉及夹具的安装：在同一腰椎两侧进针点按Wein-stein法，取外倾角5°组外倾角5°，外倾角15°组外倾角15°，外倾角30°组外倾角30°。针孔准备用3.0mm钻头打孔深50mm，拧入椎弓根螺钉50mm，钉尾部用横向牵引装置连接。用特制夹具固定脊椎椎体和DTTs。② 把持力测定及椎弓根和椎体损伤观察：分别将已安装好椎弓根螺钉及横向牵引装置的脊椎椎骨连同夹具一起安置到EW型电子万能材料实验机上，测定椎弓根螺钉的把持力。传感器与电脑相连，并绘出力－位移曲线。以曲线波峰为最大把持力。同时观察椎弓根螺钉拔出时椎弓根和椎体损伤情况。 主要观察指标：把持力检测结果及椎弓根和椎体损伤情况。 结果：①最大把持力：外倾角5°组、外倾角15°组及外倾角30°组椎弓根螺钉平均最大把持力分别为0.878 167，1.420 333，2.154 167 KN。组间比较差异有显著性意义（F = 12.554 22， P < 0.01）。②椎弓根和椎体损伤情况：外倾角5°组4例椎弓根入口处骨皮质骨折，2例椎弓根与椎体后缘交界区断裂；外倾角15°组1例椎弓根入口处骨皮质骨折，4例椎弓根与椎体后缘交界区断裂，1例椎体后缘冠状面断裂；外倾角30°组1例椎弓根入口处骨皮质骨折，2例椎弓根与椎体后缘交界区断裂，3例椎体后缘冠状面断裂。组间秩和检验，差异有显著性意义（P < 0.01）。 结论：在应用经椎弓根螺钉置入机体内固定并加用横向牵引装置时，适当增加外倾角，可增大螺钉的把持力，提高固定强度，外倾角过大则易对椎体造成破坏。     

螺旋CT扫描下测量颈椎椎弓根尺寸及螺钉置入角度

背景：在所有固定颈椎的技术上，椎弓根螺钉内固定可提供最大稳定性，但如进钉角度不正确易伤及颈髓、神经根和椎动脉。 目的：测量下颈椎椎弓根尺寸和螺钉置入角度。 设计、时间及地点：以正常人颈椎为对象的对比观察，于2004-12/2008-05在惠州市中心人民医院放射科完成。 对象：选择惠州市中心人民医院骨科收治怀疑颈椎损伤患者60例，男30例，平均(42.9±18.9)岁；女30例，平均(42.2±14.9)岁。排除颈椎病理改变。CT下画经过椎弓根内外侧2条平行线与中线分别成50°和25°角，测量2条平行线间的垂直距离。 方法：60例患者行颈椎CT扫描，扫描范围C2~T1，扫描电压140 kV，电流200~250 mA。 主要观察指标：测量C3~C7椎弓根外径、内径和内壁皮质骨厚度，椎弓根轴长度、椎弓根进钉点到中线的垂直距离、椎弓根长轴与中线的夹角及椎弓根螺钉的有效距离。 结果：颈椎椎弓根平均内径为1.3~3.3 mm，平均外径为4.0~7.0 mm，最小的椎弓根宽度在女性C3椎体，最小的椎弓根外径为3.2 mm，最大椎弓根宽为C7，男性为11.1 mm，女性为6.6 mm。平均内壁皮质骨厚度为1.5~1.9 mm，平均椎弓根轴长度29.3~33.7 mm，平均椎弓根长轴与中线的夹角40.6°~49.6°，颈椎弓根钉进钉点到中线的垂直距离平均为20.2~23.7 mm。椎弓根螺钉的有效距离(与中线成50°角)平均值3.8~6.6 mm，最小值2.2 mm，与中线成25°角的平均值2.8~4.4 mm，最小值1.4 mm。 结论：颈椎椎弓根螺钉的置入应行CT测量，螺钉角度接近50°，进钉时保持向内的倾斜角度，防止损伤脊髓和椎动脉。     

单、双侧后外侧椎弓根钉置入并植骨融合治疗退变性腰椎滑脱的随机对照

背景：节段融合辅以椎弓根钉置入内固定治疗退变性腰椎疾病可提高融合率。 目的：比较单、双侧椎弓根钉置入内固定并植骨融合治疗退变性腰椎滑脱的临床疗效和融合率。 方法：将退变性腰椎滑脱患者随机分为2组,分别行双侧与单侧椎弓根钉置入内固定并植骨后外侧融合。 结果与结论：两组患者失血量、输血量、住院时间、手术并发症、临床疗效、融合率和对临近间盘的影响方面差异无显著性意义。单侧内固定组手术操作时间较双侧内固定组明显缩短(P < 0.001)。双侧内固定组置入186枚椎弓根螺钉中有3枚穿透皮质刺激神经根而行二次手术;单侧内固定组置入90枚螺钉未发生与螺钉置入相关的并发症。表明退变性腰椎滑脱患者行单侧和双侧椎弓根钉置入并植骨内固定后外侧融合效果相同,但单侧内固定成本费用低、节省手术时间,置钉时穿破椎弓根皮质刺激神经根的风险小。     

中上胸椎后路半椎弓根入路置钉固定技术的临床应用*

背景：中上胸椎矫形固定以椎弓根钉置入内固定三维稳定性最佳,效果最好,但由于胸椎椎弓根解剖上较腰椎窄细,且胸椎管内是脊髓,内固定的难度和风险较高。 目的：分析中上胸椎后路半椎弓根入路置钉固定技术的临床应用效果。 方法：应用后路半椎弓根入路置钉固定治疗中上胸椎疾病患者58例,在T1~T2可应用直径4.5 mm、长度30 mm的螺钉,T3~T8应用直径5.0~6.0 mm、长度35~40 mm的螺钉,螺钉直径均在4.5 mm以上。 结果与结论：置钉固定后胸椎X射线片及CT显示,无螺钉进入椎管内,脊柱序列恢复良好,无内固定松动及断钉等并发症发生;置钉后无脊髓损伤加重及感染等并发症。患者生活完全恢复,疼痛消失16例;不全性和完全性截瘫46例日常生活能够自理,胸背部疼痛消失,无后凸畸形。表明中上胸椎半椎弓根入路置钉技术选用较粗、较长螺钉置入内固定效果可靠,安全,且进钉技术相对简单,易于掌握,可作为中上胸椎后路内固定的良好选择。     

胸椎椎弓根-肋骨复合体螺钉置入内固定的应用解剖学特征

背景：上、中胸椎周围结构复杂,椎弓根的横径相对窄小,如再合并发育畸形,导致螺钉不能置入,或者置入后造成副损伤,置钉安全性和有效性得不到保证。 目的：提出“椎弓根-肋骨复合体”的概念,观察其形态结构,分析其在解剖学上置入螺钉的可行性。 方法：观察6具成人尸体胸椎标本(T1~12)椎弓根及椎弓根-肋骨复合体的形态结构,测量下列参数：横径、纵径、椎弓根-肋骨复合体轴线螺钉置入最长值、椎弓根-肋骨复合体轴线螺钉横断面角及椎弓根-肋骨复合体轴线螺钉与椎弓板的夹角。 结果与结论：椎弓根-肋骨复合体是一立体结构,椎弓根与肋骨不在同一平面,且两者位置关系随不同节段而发生变化。横径为13.0~17.3 mm,纵径为5.8~8.0 mm,椎弓根-肋骨复合体轴线螺钉置入最长值为43.4~60.5 mm,椎弓根-肋骨复合体轴线螺钉横断面角为15.4°~36.7°,椎弓根-肋骨复合体轴线螺钉与椎弓板的夹角为76.2°~85.4°。提示沿胸椎经椎弓根-肋骨复合体轴线置入螺钉内固定时,安全范围较大。应用于临床时,可作为椎弓根螺钉内固定的一种补充,特别是在无法完成椎弓根螺钉置入的胸椎平面。     

个体优化经椎弓根置钉复位内固定治疗胸腰椎骨折

背景：在日臻成熟的椎弓根螺钉应用技术中,仅满足于将螺钉置入椎弓根中是不够的,而是应根据骨折复位固定要求寻求最佳置钉通道。 目的：验证经椎弓根内固定个体化治疗胸腰椎骨折的有效性和安全性。 方法：对50例胸腰椎骨折患者内固定前X射线片和CT片进行个体化矢状面及水平面椎弓根螺钉置入角、椎弓根横径、间距、钉道深度、椎体前后高、脊柱后凸角及椎管前后径测量,确定胸腰段椎弓根钉道个体优化置钉和复位的安全范围。术中结合解剖定位标志,C臂X射线机监控置钉并复位骨折椎体,确定复位结果。 结果与结论：置钉位置良好,角度及深度适中,内固定后骨折椎体复位高度、后凸角及椎管面积改善(P < 0.01)。经2~26个月随访,骨折均愈合。提示在胸腰段椎弓根钉道个体化影像测量安全范围内,优化置入椎弓根钉和复位是保证置钉内固定安全和椎体骨折复位合理而有效的方法。     

框架立体定向图像引导颈椎弓根螺钉个体化置钉的实验研究

目的探索一种基于虚拟现实可视化技术的颈椎弓根螺钉置钉方法。方法选取6例成人颅-颈椎标本，改进的四柱式定位框架以螺钉固定于枕颈部，使颅-颈-肩形成统一刚性结构，保持空间位置恒定。CT薄层扫描获取60个椎弓根的空间定位数据，Aero—tech手术规划系统三维建模，设计安全、个体化的置钉路径，导向弓把持下经皮细钻钻孔，套管针导引下置入攻丝，复查CT评价置钉的准确性。结果60个椎弓根置钉中，攻丝与规划路径有偏差者8个，失败率为13％，横突孔方向突破5个，椎管骨皮质突破3个；6例位于C（3-5）（占75％）；2例位于C1、C2椎体（占25％）。结论框架立体定向图像引导的颈椎弓根螺钉个体化置入方向精确，减少置钉的并发症，置钉过程直观、简单，能术前虚拟演示，有临床应用前景。     

三维CT测量在骶髂关节个体化置钉中的应用

背景：骶髂螺钉直接固定复位后的骶髂关节，可提供足够的骨盆稳定性，其生物力学稳定性优于其他常用的内固定。 目的：探讨三维CT测量在骶髂关节个体化置钉中的应用，为临床个体化置钉提供影像解剖学的依据。 设计、时间及地点：测量实验，于2008-01/07在河北工程大学CT中心及解剖实验室完成。 材料：成人骶髂关节标本8例，男女年龄不限，无脊柱疾病，由河北工程大学医学院解剖教研室提供，体积分数为0.1的甲醛处理。 方法：每例标本的S1均经螺旋CT断层扫描后，图像输入到计算机软件，对图像进行处理，测量S1椎弓根骶髂关节的钉道直径，骶髂关节于髂骨后外侧面的进针点，骶髂关节螺钉的长度及进针方向，并根据数据模拟出各椎弓根的形态特点，依测量的数据和角度在标本上置钉，再行CT扫描观察螺钉在椎弓根内的位置。 主要观察指标：骶髂关节螺钉参数的数值，置钉后椎弓根钉的在位率。 结果：S1椎弓根宽为(24.6±2.7) mm，高为(19.1±2.9) mm，进针点至对侧前皮质的距离为(87.1±3.2) mm，进针方向与冠状面的夹角为(24.9±1.5)°，与矢状面夹角为(21.2±1.6)°，进针点与骼后上棘的距离为(37.5±2.6) mm，与骼后下棘的距离为(38.5±2.7) mm；与坐骨大切迹的距离为(43.2±4.6) mm，双侧16次穿钉，15枚骶髂关节螺钉完全在位。 结论：利用三维CT测量的数据辅助，严格按照个体化椎弓根的轴线方向置钉，置钉的成功率较高。     

Pedicle Screw Placement in the Thoracolumbar Spine Using a Novel,Simple, Safe,and Effective Guide-Pin : A Computerized Tomography Analysis

ObjectiveTo improve pedicle screw placement accuracy with minimal radiation and low cost, we developed specially designed K-wire with a marker. To evaluate the accuracy of thoracolumbar pedicle screws placed using the novel guide-pin and portable X-rays.MethodsObservational cohort study with computerized tomography (CT) analysis of in vivo and in vitro pedicle screw placement. Postoperative CT scans of 183 titanium pedicle screws (85 lumbar and 98 thoracic from T1 to L5) placed into 2 cadavers and 18 patients were assessed. A specially designed guide-pin with a marker was inserted into the pedicle to identify the correct starting point (2 mm lateral to the center of the pedicle) and aiming point (center of the pedicle isthmus) in posteroanterior and lateral X-rays. After radiographically confirming the exact starting and aiming points desired, a gearshift was inserted into the pedicle from the starting point into the vertebral body through the center of pedicle isthmus.ResultsNinety-nine percent (181/183) of screws were contained within the pedicle (total 183 pedicle screws : 98 thoracic pedicle screws and 85 lumbar screws). Only two of 183 (1.0%) thoracic pedicle screws demonstrated breach (1 lateral in a patient and 1 medial in a cadaver specimen). None of the pedicle breaches were associated with neurologic or other clinical sequelae.ConclusionA simple, specially designed guide-pin with portable X-rays can provide correct starting and aiming points and allows for accurate pedicle screw placement without preoperative CT scan and intraoperative fluoroscopic assistance.     

Inferolateral Entry Point for C2 Pedicle Screw Fixation in High Cervical Lesions

Objective

The purpose of this retrospective study was to evaluate the efficacy and safety of atlantoaxial stabilization using a new entry point for C2 pedicle screw fixation.

Methods

Data were collected from 44 patients undergoing posterior C1 lateral mass screw and C2 screw fixation. The 20 cases were approached by the Harms entry point, 21 by the inferolateral point, and three by pars screw. The new inferolateral entry point of the C2 pedicle was located about 3-5 mm medial to the lateral border of the C2 lateral mass and 5-7 mm superior to the inferior border of the C2-3 facet joint. The screw was inserted at an angle 30° to 45° toward the midline in the transverse plane and 40° to 50° cephalad in the sagittal plane. Patients received followed-up with clinical examinations, radiographs and/or CT scans.

Results

There were 28 males and 16 females. No neurological deterioration or vertebral artery injuries were observed. Five cases showed malpositioned screws (2.84%), with four of the screws showing cortical breaches of the transverse foramen. There were no clinical consequences for these five patients. One screw in the C1 lateral mass had a medial cortical breach. None of the screws were malpositioned in patients treated using the new entry point. There was a significant relationship between two group (p=0.036).

Conclusion

Posterior C1-2 screw fixation can be performed safely using the new inferolateral entry point for C2 pedicle screw fixation for the treatment of high cervical lesions.     

计算机导航辅助椎弓根螺钉固定的临床研究

目的椎弓根螺钉固定是脊柱病变切除后稳定性重建的标准方法。常规术中透视监测行颈胸节段椎弓根螺钉固定具有相当挑战性,本文旨在就计算机导航辅助椎弓根螺钉固定技术进行初步分析。方法2005年1月至2006年3月在计算机导航系统辅助下,对21例患者（年龄17～63岁,平均43．4岁）共行102枚椎弓根螺钉固定。术前采用0．75mm薄层螺旋CT数据扫描并导入计算机工作站进行脊柱三维重建;术中进行工具注册和匹配后对椎弓根螺钉固定进行实时显示。术后所有病例均采用CT和X线平片随访监测效果。结果手术顺利,螺钉大小选择合适,102枚椎弓根螺钉中100枚螺钉（98%）固定位置及方向准确,2枚椎弓根螺钉突破椎弓根外壁距离小于2mm。所有操作均未发生血管和神经损伤并发症。术中透视次数及手术室人员所受X线辐射量明显减少。结论计算机导航辅助椎弓根螺钉固定是一项安全的手术,且手术精度高。     

三维虚拟图像导航技术在脊柱椎弓根螺钉固定中的应用☆

背景：近年来经椎弓根螺钉固定技术显著提高了脊柱固定强度和融合效率,但是椎弓根螺钉置入位置不佳可能损害脊髓和神经引起严重并发症。 目的：评估置入前CT扫描三维虚拟图像导航技术在脊柱椎弓根螺钉固定中的应用价值。 设计、时间及地点：前瞻性、随机对照观察,于2006-01/2008-12在中国医学科学院北京协和医院骨科完成。 对象：纳入因脊柱疾病行椎弓根螺钉固定的患者95例,导航组45例,常规组50例。 方法：将95例患者按随机数字表法分为2组,导航组术中在计算机导航技术辅助下置入椎弓根螺钉,常规组采用传统的解剖标志法结合术中透视定位置入椎弓根螺钉。 主要观察指标：比较2组间螺钉钉道准备时间、螺钉位置优良率及螺钉置入后并发症的发生率。 结果：导航组中36例患者共置入椎弓根螺钉206枚,优良率96.1%;有9例患者因故未能行导航。常规组50例患者共置入椎弓根螺钉285枚,优良率100.0%,无位置差的螺钉。2组患者的螺钉位置优良率差异无显著性意义(P > 0.05)。导航组的钉道准备时间显著长于常规组[(360±22),(56±8) s,P < 0.01]。2组患者螺钉置入后均无并发症发生。 结论：与传统解剖标志定位法相比,应用置入前CT扫描三维虚拟图像导航技术置入椎弓根螺钉的精度无明显差异,且延长了手术时间,其在脊柱椎弓根螺钉固定中的应用价值有限。     

Cortical bone trajectory technique’s outcomes and procedures for posterior lumbar fusion: A retrospective study

Cortical Bone Trajectory screws allow a limited soft tissue dissection with mechanical properties comparable to traditional pedicle screws. However, clinical results are still reported on limited samples.The study aimed to evaluate perioperative and mid-term follow up outcomes, clinical results and complications in 238 consecutive patients underwent CBT fusion for degenerative lumbosacral disease.Pre- and intraoperative data, clinical outcomes and complications were collected. The patients were stratified in three groups. The original technique was performed in the first 43 cases without a preoperative CT scan planning. The second group includes the patients who underwent preoperative CT scan for entry point and screw trajectory planning (158 patients). Surgical procedures in the last group were performed with patient-matched 3D printed guide (37 patients). The accuracy in screws positioning was evaluated on postoperative CT scan.The mean follow-up was 32.3 months. Mean ODI and VAS index improved with statistical significance. Mean procedural time was 187, 142 and 124 min in the three subgroups. The total amount of recorded complications was 4.2% (16.3%, 3.8% and 0.0% respectively). Screws entirely within the cortex of the pedicle were 78.9%, 90.5% and 93.9% in the three groups. Fusion was obtained in 92.4% of cases.The CBT technique is a safe procedure, especially with an accurate preoperative CT scan-based planning. This seems more evident with the 3D template patient-matched guide. More studies are needed to directly compare traditional pedicle screws and CBT screws on long-term outcomes.     

颅颈交界区后路螺钉内固定

目的 报告C2椎弓根螺钉结合C1侧块或枕骨螺钉用于颅颈交界区后路内固定的解剖研究及临床应用结果.方法 福尔马林固定的头颈标本4个,根据解剖标志分别植入C2椎弓根及C1侧块螺钉,然后行CT扫描及重建,观察螺钉位置.2004年5月至2007年1月,利用C2椎弓根一C1侧块/枕骨螺钉内同定9例病人,男4例,女5例,年龄12～68岁,平均38岁;各种原因引起的C1～C2半脱位6例,因颅底凹陷经口腔齿状突切除后1例,斜坡脊索瘤经口腔切除手术前2例;采用C2椎弓根-C1侧块螺钉技术4例,C2椎弓根一枕骨螺钉技术5例,手术后均行CT扫描观察螺钉位置.结果 手术中直接显露C2椎弓根内上缘,并以此确立进钉方向,在椎弓根峡部后缘确定进钉点,可保证C2椎弓根螺钉的安全植入;直接显露C1侧块后正中确立进钉点,可避免螺钉植入过程中的椎动脉损伤.9例病人中,手术后CT复查有2例病人两颗螺钉穿破骨皮质,但末造成血管及神经的压迫,其余螺钉位置均较好;随访4-32个月,1例临床症状较术前无变化,其余8例均改善.结论 C2椎弓根-C1侧块/枕骨螺钉技术可安全有效地用于颅颈交界区内固定.     

Pedicular and Extrapedicular Morphometric Analysis in the Korean Population : Computed Tomographic Assessment Relevance to Pedicle and Extrapedicle Screw Fixation in the Thoracic Spine

Objective

To evaluate the anatomical parameters that must be considered when performing thoracic transpedicular or extrapedicular screw fixation.

Methods

We selected 958 vertebrae (1,916 pedicles) from 98 patients for analysis. Eight parameters were measured from CT scans : the transverse outer pedicular diameter, transverse inner pedicular diameter, length, angle, chord length of the pedicles and the transverse width, angle, and chord length of the pedicle-rib units.

Results

The age of the patients ranged from 21 to 82 years (mean : 48.2 years) and there were 57 men and 41 women. The narrowest transverse outer pedicular diameter was at T5 (4.4 mm). The narrowest pedicle length was at T1 (15.9 mm). For pedicle angle, T1 was 31.6 degrees, which was the most convergent angle, and it showed the tendency of the lower the level, the lesser the convergent angle. The chord length showed a horizontal pattern with similar values at all levels. For the PRU width, T5 showed a similar pattern to the pedicle width at 13.4 mm. For the PRU angle, T1 was the largest angle at 46.2 degrees and the tendency was the lower the level, the narrower the angle. For chord length, T1 was the shortest at 46.9 mm and T8 was the longest at 60.1 mm.

Conclusion

When transpedicular screw fixations carried out at the mid-thoracic level, special care must be taken because there is a high chance of danger of medial wall violation. In these circumstances, extrapedicular screw fixation may be considered as an alternative treatment.     

The Use of Pedicle Screw-Rod System for the Posterior Fixation in Cervico-Thoracic Junction

Objective

In cervico-thoracic junction (CTJ), the use of strong fixation device such as pedicle screw-rod system is often required. Purpose of this study is to analyze the anatomical features of C7 and T1 pedicles related to screw insertion and to evaluate the safety of pedicle screw insertion at these levels.

Methods

Nineteen patients underwent posterior CTJ fixation with C7 and/or T1 included in fixation levels. Seventeen patients had tumorous conditions and two with post-laminectomy kyphosis. The anatomical features were analyzed for C7 and T1 pedicles in 19 patients using computerized tomography (CT). Pedicle screw and rod fixation system was used in 16 patients. Pedicle violation by screws was evaluated with postoperative CT scan.

Results

The mean values of the width, height, stable depth, safety angle, transverse angle, and sagittal angle of C7 pedicles were 6.9 ± 1.34 mm, 8.23 ± 1.18 mm, 30.93 ± 4.65 mm, 26.42 ± 7.91 degrees, 25.9 ± 4.83 degrees, and 10.6 ± 3.39 degrees. At T1 pedicles, anatomic parameters were similar to those of C7. The pedicle violation revealed that 64.1% showed grade I violation and 35.9% showed grade II violation, overall. As for C7 pedicle screw insertion, grade I was 61.5% and grade II 38.5%. At T1 level, grade I was 65.0% and grade II 35.0%. There was no significant difference in violation rate between the whole group, C7, and T1 group.

Conclusion

C7 pedicles can withstand pedicle screw insertion. C7 pedicle and T1 pedicle are anatomically very similar. With the use of adequate fluoroscopic oblique view, pedicle screw can be safely inserted at C7 and T1 levels.