枢椎后路3种螺钉固定技术生物力学测试的对比研究

Comparison study of biomechanical test among fixation techniques of three types screw of posterior approach for C_2

目的:评价单皮质和双皮质枢椎椎弓根螺钉、枢椎侧块螺钉和枢椎椎板螺钉的固定强度,为临床选择后路螺钉的固定方式提供生物力学依据。方法:利用30具新鲜尸体枢椎标本,进行单皮质和双皮质的枢椎椎弓根螺钉、枢椎侧块螺钉、枢椎椎板螺钉固定,测试比较其螺钉拔出强度。结果:双皮质枢椎椎弓根螺钉的拔出力量最大,为(1255.8±381.9)N;单皮质枢椎椎弓根螺钉[(901.8±373.3)N]、双皮质枢椎侧块螺钉[(776.1±306.8)N]和双皮质枢椎椎板螺钉[(640.8±302.9)N]之间差异无统计学意义。结论:枢椎后路螺钉固定宜首选椎弓根螺钉,枢椎侧块螺钉和枢椎椎板螺钉可作为枢椎后路补充固定技术,且以双皮质骨固定为宜。

Objective：To evaluate the screw pull-out strength of posterior C2 when the screw is fixed to C2 through the trans-pedicle or lateral mass or trans-laminar unieortieally or bieortically, so as to provide biomeehanical basis for the clinical application of posterior C2 screw fixation technique. Methods：The pedicle screw,the lateral mass screw or the laminar screw was separately anchored into 30 fresh C2 specimens unicortically or bicortically. The screw pull-out strength of different fixation was tested and compared with the others. Results：The average pull-out strength of C2 bicortical pedicle screw was （1 255.8± 381.9） N, the strongest during all the methods. The mean pull-out strength of C2 unicortieal pediele screw, C2 bicortical lateral mass screw and C2 bicortical laminar screw were （901.8±373.3） N, （776.1±306.8） N and （640.8±302.9） N respectively,with no statistical difference. Conclusion ： Pedicle screw should be the first choice for the posterior fixation on axis. C2 lateral mass screw fixation and C2laminar screw fixation can be another supplement choice and the screw had better be placed bicortically.