下颈椎前路椎弓根螺钉置入相关的解剖学观察

Anterior pedicle screw insertion for low cervical spine：anatomical observation

摘要:

目的：观察成人下颈椎前路椎弓根螺钉（Anterior pedicle screw，ＡＰＳ）置入相关的径线和角度，为该术的临床应用提供相关解剖学参数。方法：成人干燥尸体下颈椎（C3～C7）标本22具，分别用手工和CT测量椎弓根最窄处的高度、宽度及内外侧皮质厚度，椎弓根中轴线全长，轴线夹角，并进行统计学分析。随机在CT室资料库中抽取100例成人活体颈椎CT图像，用Mimics软件行三维重建，除以上参数外，还测量进钉点位置的相关数据，计算置钉参数的95%CI。结果：22具标本的相关径线及角度，其手工测量值与CT测量值间无统计学差异。成人活体下颈椎CT图像测量结果通过95%CI的计算，可以得出：C3、C4进钉点位于椎体正中矢状面受术椎弓根对侧 2~3 mm，距椎体上终板平面 6~7 mm，进钉角度为外倾角 46°~ 48°，头倾角 C3：-11°~-12°，C4 -6°~-7°。C5 进钉点位于椎体正中矢状面受术椎弓根同侧旁 1~2 mm，距椎体上终板平面 7~8 mm，进钉角度为外倾角 47°~49°，头倾角 1°~2°。C6、C7 进钉点位于受术椎弓根同侧，正中矢状面旁 4~5 mm，距椎体上终板平面 7.5~8.5 mm，进钉角度为外倾角 C6：40°~42°，C7：36°~38°，头倾角 C6：6°~7°，C7：11°~13°。置钉长度选择 30、32、34 mm 较为适宜，螺钉直径可选择 3.5 mm 或 4.0 mm。结论：本实验证实了CT测量下颈椎APS置入技术相关参数的准确性，同时在国内首次利用大样本研究对该技术置钉参数进行了探索。

Abstract:

Objective：To observe the pathlines and angles related to lower cervical spine anterior pedicle screw（APS） fixation in adults so as to provide anatomical parameters in clinics. Methods：A total of 22 cervical spine（C3-C7） specimens of human adult cadavers were individually measured by hand and CT scan to determine the height and width of the narrowest part in pedicle，thickness of inner and outer cortexes，pedicle axis length and included angle of axes followed by statistical methods. One hundred pieces of CT images from CT database were randomly selected，then three-dimensional model reconstruction was performed by Mimics software，relative parameters of screw insertion point were measured and 95% confidence interval of screw insertion parameters was also calcu－lated. Results：No significant difference of pathlines and angles measurements of 22 specimens was found between manual work group and CT scan group. Based on the calculation of measurements of adult lower cervical spines in CT images with 95% confidence inter－val，the insertion points for C3 and C4 was 2-3 mm opposite from operated pedicle in centrum median plane and 6-7 mm from upper end-plate of centrum plane，the outside inclined angle of screw insertion was 46°- 48°. Cranially inclined angles for C3 and C4 were -11°--12° and -6°--7° respectively. The insertion point for C5 was 1-2 mm beside operated pedicle in centrum median plane and 7-8 mm from upper end-plate of centrum plane，the outside and cranially inclined angles of screw insertion were 47°- 49° and 1°-2° respectively. The insertion points for C6 and C7 were at the same side with operated pedicle，4-5 mm beside centrum median plane and 7.5-8.5 mm from upper end-plate of centrum plane. The outside inclined angles of screw insertion for C6 and C7 were 40°- 42° and 36°-38° respectively，cranially inclined angles were 6°-7° and 11°-13°. For insertion screws，the length should be 30 mm，32 mm or 34 mm and the diameter should be 3.5 mm or 4.0 mm. Conclusions：This study confirms the accuracy of CT scan in the measurement of lower cervical spine and APS fixation related parameters and makes an exploration in technical range of parameters for the first time in the country using a large sample.