胸椎椎弓根螺钉植入位置的分区及临床意义

A new kind of grade system for thoracic pedicle screw placement and its clinical purpose

目的探讨术后CT扫描对胸椎椎弓根螺钉位置分区及其临床意义。方法对64例共450枚胸椎椎弓根螺钉固定患者的临床资料进行统计分析。所有患者术后均采用手术节段椎弓根CT扫描,根据椎弓根螺钉在CT片显示的位置及可能引起的危险将其分为A、B、C三个区:A区,螺钉位置正常(椎弓根螺钉位于椎弓根中央,未穿透椎弓根和椎体,深度合适)。B区,螺钉引起椎弓根部分皮质破裂或穿透椎体前方或侧方,但没有引起严重的神经或血管损害。同时,将椎弓根螺钉偏向椎弓根外侧或上方、内侧或下方、穿透椎体前方或侧方分别划分为B1、B2、B3三个部分。C区,椎弓根螺钉位置严重偏差,直接威胁脊髓、神经根或大血管。平均随访时间25.8个月。比较胸椎不同位置使用椎弓根螺钉固定时椎弓根螺钉的准确位置及术后可能因为椎弓根螺钉位置偏差引起的并发症。结果A区共367枚(81.6%),B区78枚(17.3%),其中B1区40枚(8.8%)、B2区23枚(5.1%)、B3区15枚(3.4%),C区5枚(1.1%)。从结果看T36节段最容易发生椎弓根螺钉的位置错误。结论根据CT扫描影像结果对椎弓根螺钉位置进行分区,有助于准确判断椎弓根螺钉的位置,预防并发症的发生。

Objective To introduce a new kind of grade system for thoracic pedicle screws placement by performing postoperative computerized tomography （CT） scanning and discussion the clinical purpose. Methods Four hundred and fifty thoracic pedicle screws were implanted in 64 patients with the assistance of fluoroscopy. Postoperative CT scanning was conducted to determine a grade for each screw ： Part A, screw entirely contained within pedicle ; Part B1 , violate lateral or upper pedicle but screw tip entirely contained within the vertebral body（VB） ; PartB2, violate medial or inferior of pedicle ; Part B3 , tip penetrated anterior or lateral VB ; Part C, violate pedicle or VB and endangers spinal cord, nerve roots, or great vessels. Based on anatomical morphometry, thoracic vertebral were subdivided into upper （T1-2 ）, middle（ T3-6 ）, and lower （T7-12） regions. The mean follow-up period was 25.8 months. Results The postoperative CT scanning-documented grade were determined ： Part A, 367 screws （ 81.6% ） ; Part B, 78 （17.3%）, B140（8.1%）; PartB2, 23（5.1%）; Part B3, 15（3.4%）; PartC, 5（1.1%）. Therewere not significant difference between upper and lower thoracic that the placement of pedicle screws in part B or C. In part C,5 pedicle screws were all in the middle thoracic. Condusion Postoperative CT scanning should be considered as a routine examination for evaluating thoracic pedicle screw placement.