CT血管造影枢椎椎弓根矢状面术前评估方法的临床应用

Application of thin CT angiography of pedicle sagittal plane of axis for preoperative evaluation of pedicle screw placement procedure

目的探讨CT血管造影(CT angiography,CTA)薄层扫描枢椎椎弓根矢状面术前评估在个体化置钉中的应用价值。方法回顾性分析2016年2月—2017年8月行后路枢椎内固定患者34例、68个椎弓根,术前接受薄层CTA扫描。统计椎动脉发育情况;测量并读数枢椎矢状面横突孔处椎弓根高度≥4 mm连续层数(f);记录枢椎内固定方式;CT扫描术后椎弓根螺钉钉道;有无椎动脉及脊髓损伤的临床表现,骨折或植骨愈合情况。结果右侧为优势血管者8例,左侧为优势血管者18例,均衡者8例。16个椎弓根f>9层,27个椎弓根f=9层,17个椎弓根f=8层,8个椎弓根f<8层。f≥9层的43个椎弓根采用螺钉固定;f=8层的17个椎弓根中,16个采用椎弓根螺钉固定,1个采用椎板螺钉固定;f<8层的8个椎弓根中,4个采用椎弓根螺钉固定,4个采用椎板螺钉固定。f>9层的椎弓根螺钉钉道分级A级14个,B级2个,C级0个;f=9层的椎弓根螺钉钉道分级A级16个,B级7个,C级4个;f=8层的椎弓根螺钉钉道分级A级3个,B级5个,C级8个;f<8层的椎弓根螺钉钉道分级A级0个,B级0个,C级4个;另外4个椎板螺钉固定均未侵犯椎管。术后f<8层的1例C级患者出现轻度头晕、嗜睡临床表现。术后获得6~11个月随访,平均随访(8±3)个月,6个月以上见骨折或植骨融合。结论基于术前CTA薄层扫描,通过读数枢椎CT/CTA矢状层面上横突孔处椎弓根高度≥4 mm连续层数,可以有效判断枢椎椎弓根螺钉的安全性,确定合理的手术方式,从而提高椎弓根固定的成功率,降低手术风险。

Objective To explore the application value of thin CT angiography（CTA） of pedicle sagittal plane of axis for preoperative evaluation planning pedicle screw placement. Methods Between February 2016 and August 2017,34 patients（68 pedicles） who underwent thin CTA scan before posterior axial surgery were retrospectively analyzed. The vertebral artery development was statistically analyzed. The continuous layers of transverse process hole pedicle height more than or equal to 4 mm（f） were measured and read. The axial fixation methods, clinical manifestations of vertebral artery and spinal cord injury and the bone union of fractures or implants were recorded. Postoperative results of pedicle screws were evaluated by CT scan. Results The right sides of 8 cases and the left sides of 18 cases were dominant vertebral arteries, and equilibrium was reached in 8 cases; f〉9 layers were found in 16 pedicles, f=9 layers in 27 pedicles,f=8 layers in 17 pedicles, and f8 layers in 8 pedicles. The 43 pedicles of f≥9 layers used pedicle screw fixation; in the 17 pedicles of f=8 layers, 16 used pedicle screw fixation, and the other one used laminar screw fixation; in the 8 pedicles of f8 layers, 4 used pedicle screw fixation, and the other 4 used laminar screw fixation. A self-defined pedicle screw grading system was used to evaluate the excellence, and the result showed that, f〉9 layers： 14 pedicles were class A, 2 were class B,none was class C; f=9 layers： 16 pedicles were class A, 7 were class B, 4 were class C; f=8 layers： 3 pedicles were class A,5 were class B, 8 were class C; f8 layers： none was pedicles class A or class B, 4 were class C. The other 4 lamina screws fixation didn＇＇t invade the spinal canal. One case of pedicle class C showed clinical manifestations of mild dizziness and drowsiness. The patients were followed up for 6-11 months with an average of（8±3） months, and the fracture or bone graft fusion were observed after 6 months of following-up. Conclusion Based on preoperative CTA thin layer scanning,through measuring and reading continuous layers of transverse process hole pedicle height more than or equal to 4 mm,can effectively judge the security of axial pedicle screws in order to subsequently choose the reasonable operation methods so as to improve success rate and decrease surgical risk.