椎动脉CT血管造影多平面重组在枢椎椎弓根置钉中的价值

The significance of CT multi-planar reconstruction of vertebral artery CT angiography in C2 pedicle screw placement

中文关键词:  枢椎  椎弓根螺钉  多平面重组  椎动脉  CT血管造影

英文关键词:Axis  Pedicle screw  Multi-planar recontruction  Vertebral artery  CT angiography

中文摘要:

  【摘要】 目的：探讨椎动脉CT血管造影（CTA）多平面重组在枢椎椎弓根置钉中的价值。方法：利用CT多平面重组技术，对77例患者的椎动脉CTA容积数据进行回顾性CT多平面重组。依据椎弓根置钉理想钉道方向调整CT多平面重组的定位线，重建出螺钉穿过椎弓根复合体的切面断层，用一个标定圆模拟螺钉横截面，根据标定圆直径、标定圆与椎动脉的位置关系及其在椎弓根复合体内的容纳情况评估置钉的可行性。同时，对椎弓根内径进行测量，评价置钉的风险。比较两种方法判定结果之间的差异。结果：基于椎动脉CTA的多平面重组可明确显示椎弓根螺钉在枢椎内的容纳情况及与周围解剖结构的位置关系。根据该方法判定双侧枢椎中不能容纳直径4mm标定圆、不宜行椎弓根置钉术者：左侧10例（13%），右侧19例（25%）；根据内径测量判定不宜行椎弓根置钉术者：左侧12例（16%），右侧20例（26%）。McNemar配对χ2检验P值双侧分别为：左P＝0.5，右P＝1，两种方法判定结果无显著性差异。Kappa检验两种方法的一致性分别为：左侧Kappa值＝0.770，P＝0；右侧Kappa值＝0.732，P＝0，两种方法一致性较好。结论：椎动脉CTA多平面重组可明确显示椎弓根螺钉在枢椎内的容纳情况及与周围解剖结构的位置关系，为选择枢椎椎弓根螺钉大小及制定手术计划提供参考。

英文摘要:

  【Abstract】 Objectives: To investigate the significance of CT multi-planar reconstruction of vertebral artery CT angiography(CTA) in C2 pedicle screw placement. Methods: The vertebral artery CTA images of 77 patients were reviewed retrospectively by CT multi-planar reconstruction. The positions in three dimensions were adjusted according to the screw′s ideal direction, and the cross section of the screw passing through the pedicle was displayed based on CT multi-planar reconstruction. A circle was demarcated on the former plane to simulate the cross section of the screw. The diameter of the circle, the accommodation of screw in C2 pedicle, and the positions of the screw related to the vertebral artery were taken into account to assess the feasibility of pedicle screw placement. And meanwhile, the feasibility was assessed by measuring the inner diameters of pedicle complex. The results of the two methods were compared. Results: The simulation of placement of C2 pedicle screw basing on CT multi-planar reconstruction illustrated the accommodation of screw in C2 and its relationship with surrounding structures. According to this method, 10(13%) cases of left side and 19(25%) cases of right side could not accommodate the circle with the diameter of 4mm and could not be placed pedicle screw, while operation was unavailable for 12(16%) cases of left side and 20(26%) cases of right side by measurement of inner diameters. The P value of McNamara test was 0.5 in the left and 1 in the right. There was no significant differences between the results of two methods(P>0.05). The result of Kappa test was 0.770 in the left and 0.732 in the right, and the P value of the Kappa test in the both sides was 0, which showed good consistency. Conclusions: The simulation of placing pedicle screw in axis basing on CT multi-planar reconstruction can illustrate the screw accommodation in C2 and its relationship with surrounding structures, which can provide good reference for the operation.