下颈椎后路固定方法的力学比较

目的：评价不同于颈椎后路内固定器的生物力学性能。方法：应用５具新鲜尸体颈椎标本（Ｃ２￣Ｃ７）建立脱位模型后，依次用棘突钢丝、侧块螺钉、自制螺钉、椎弓根螺钉固定，用材料试验机测算其垂直压缩刚度，前后水平剪切刚度和左右水平剪切刚度。结果：棘突钢丝的垂直压缩刚度和前后剪切刚度虽较完整颈椎增大，但无显著性差异（Ｐ〉０．０５），而左右剪切刚度尚较完整颈椎减小（Ｐ〈０．０５）。侧块螺钉、自制螺钉和椎弓根螺钉的

Biomechanics study on posterior lower cervical fixations

Objective: To evaluate the biomechanical properties of different posterior lower cervical fixations. Methods: After discoligmentous injury, five fresh cervical spine samples (C 2 C 7) were fixed with process wire, lateral mass screw plating, self designed lateral mass screw system, transpedicular screw plating, and were tested by material testing machine to obtain superior inferior press stiffness (SSI), anterior posterior shear stiffness (SAP) and left right shear stiffness (SLR). Results: The SSI and SAP of the process wire were larger than the intact, but was not significant ( P >0.05). The SLR of the process wire was smaller than the intact ( P <0.05). Every stiffness of the lateral mass screw plating, self designed lateral mass screw system, transpedicular screw plating was larger than the intact and the process wire ( P <0.05), and the SLR of the transpedicular screw plating was the largest ( P <0.05). Conclusion: The shear stiffness of the process wire is not good. The stiffness of the lateral mass screw plating, self designed lateral mass screw system are larger than the process wire. The stiffness of the transpedicular screw plating is the largest.