枢椎椎弓根内固定的解剖学研究

目的通过标本测量,研究以下关节突中心点为入钉点,枢椎椎弓根螺钉的进钉方法及要点。方法50枚人尸体骨干骨标本,以下关节突中心点A为进针点,在枢椎腹侧测量椎弓根的内倾角α;在椎弓背侧,选择上关节突内缘C点为标志点,测量AC连线的冠状面内倾角β,探讨α与β的相关性。结果枢椎腹侧测量的椎弓根冠状面内倾角为43°±4°(左侧),45°±5°(右侧),均值44°±6°;枢椎背侧测量的下关节突中心点A与上关节面内缘点C的连线内倾角β为39°±5°(左侧),37°±6°(右侧),均值38°±7°;α,β差值平均为5°±2°。结论①椎椎弓根部的解剖特点决定了其椎弓根螺钉的进入方向必须非常精确,否则很容易穿出椎弓根内外壁,造成椎动脉或脊髓的损伤;②枢椎下关节中心点与上关节面内缘点的连线对于确定合理的钉道方向具有较好的参考价值。

An anatomical study on the pedicle internal fixation in the axis

Objective To investigate a new method for pedicle internal fixation in the axis based on a new special land-mark.Methods Fifty human dry axis specimen were observed.Point A in the center of the lower facet were taken as enter point of pedicle screw,and point C in the medial border of superior articular process was taken as mark point.The middle inclination angle of axis pedicle(α)were measured in the bottom surface of the axis and the assistant angle(β)decided by connecting point A with point C were measured in the upper surface of axis.Results The pedicle introversion angle were:left(43±4)°;right(45±5)°,average(44±6)°.The assistant angle β were:left(39±5)°;right(37±6)°;average(38±7)°;α-β(5±2)°.Conclusion The pedicle screw of axis must be placed accurately or the vertebral artery and the vertebral canal will be violated;The assistant line connected point A with point C is helpful in axis pedicle screw placement.