寰枢椎前路侧块螺钉内固定的生物力学测试

目的比较寰枢椎前路侧块螺钉和前路钛网、前路钢板内固定后颈椎标本的稳定性,分析不同前路内固定方法对寰枢椎各个方向运动的控制作用,为临床选择应用提供参考。方法 5具新鲜冷冻保存的尸体标本,快速分离出C0～T1节段,去除表面肌肉组织,放射测定,排除骨溶解、骨折及有其他病变的标本,以自凝型牙托粉包埋C2～7节段。包埋好的标本以特殊夹具固定于三思牌测力机上进行前屈、后伸和左右侧屈刚度的测试。旋转刚度在自制的测力机上测定。结果与正常组和损伤组相比,三种内固定方法均能明显提高寰枢椎各向活动的刚度,统计检验P<0.05;术式间的比较前路螺钉组的活动刚度明显高于前路钢板(各个方向P<0.05)和前路钛网(各个方向P<0.05);前路钢板的活动刚度明显高于前路钛网(各个方向P<0.05)。结论体外颈椎标本的生物力学实验表明,无论与正常组或损伤组相比前路双侧块螺钉、前路钢板和前路钛网内固定均能提高寰枢椎的稳定性,其中前路双侧块螺钉内固定提供的稳定性最强,与简单外固定配合使用可满足临床需要,当必须行寰枢椎前路内固定时应优先考虑使用。前路钢板和前路钛网单独使用稳定性较差,虽与后路内固定术式联用或改进设计可提高稳定性,但提高了并发症风险和经济负担。

Biomechanical study of C1-2 anterior lateral mass transarticular screw fixation

Objective To evaluate the performance of Ci.2 anterior lateral mass transarticular screw fixation by biomechanical comparation with anterior atlantoaxial plating fixation and titanium mesh fixation, analyse the effect of stabilization from different fixation and offer reference for clinical application. Methods Five intact adult cadaveric cranloeervieal （C0-T1）specimens in Cryopreservation were harvested and superficial musculature was removed. Care was taken to preserve all ligaments and bone structures. Each specimen was radiographlcally screened to exclude osteolysis, fractures, or other abnormalities. Then C1-7 segments were isolated and before testing, the C2-7 segments were embedded in container full of dental base acrylic resin powder. Then the container was fixed on the lifting platform of a materials testing machine to test the stiffness of the specimens when flexion-extension and lateral bending movements were loaded. Rotation stiffness was tested on a home-made machine. Results Compared with the intact group and the unstable group,all of the three internal fixations showed conspicuous intensification for the atlantoaxial stiffness of multidirectional movement,statistic tests showed significant difference （P〈0.05）. Between the internal fixation groups,the stiffness of anterior screw fixa- tion group were higher than the other two groups and showed significant difference （P〈0.05）at all directions. The anterior plate fixation group had higher stiffness than the anterior titanium mesh fixation group（P〈0.05）. Conclusion This experiments of biomechamics indicated that all the three anterior internal fixations are able to stabilize the intact and unstable specimens obviously. The C1-2 anterior lateral mass transarticular screw fixation provided higher stiffness than the ather two fixations.the anterior plate and titanium mesh fixation provided inferior stiffness.