枢椎前路椎弓根螺钉固定通道的安全因素分析

Safety factors for anterior pedicle screw fixation tunnel in axis

目的探讨枢椎前路椎弓根螺钉通道的安全性和可行性，为经前路枢椎椎弓根螺钉固定提供理论依据。方法对32具干燥枢椎标本行前路椎弓根螺钉置入，测量枢椎前路椎弓根螺钉的钉道长度。行加密薄层螺旋CT扫描和重建，然后在重建后的横断面和矢状面图像上运用软件测量枢椎前路椎弓根螺钉的外倾角度及尾倾角度。结果枢椎椎弓根螺钉均位于椎弓根内。枢椎前路椎弓根螺钉的进钉点选择在枢椎椎体与上关节突之间凹陷的顶点，螺钉长度为（28．4±2．5）mm，外倾角度为（28．5±2．3）°，尾倾角度为（15．5±2．0）°。结论枢椎前路椎弓根螺钉不仅具有可行性，而且可以避开横突孔、椎动脉沟、椎管等重要解剖结构，安全空间较大。

Objective To investigate feasibility and safety of anterior pedicle screw fixation tun- nel in the axis so as to provide theoretic evidence for further clinical application. Methods Thirty-two dry axis specimens were used for anterior pediele screw placement, and the length of pedicle crews tunnel was measured by a digital caliper. The extraversion angle and the downslope angle were determined by CT cross-sectional scanning and reconstruction. Results All the anterior pedicle screws were positioned well, with no perforation of the pedicle. The anchoring point was at the vertex between the vertebral body and the superior articular process, with axis pedicle length of （28.4 ± 2.5 ） mm, the extraversion angle of （ 28.5 ± 2.3 ） ° and the downslope angle of （ 15.5 ± 2.0） °. Conclusions Anterior pedicle screw fixa- tion tunnel is feasible in the axis and can keep away from some important anatomy structures including transverse foramen, vertebral artery groove and vertebral canal to provide large safety space.