3种不同枕-寰-枢固定技术的生物力学比较

目的：比较3种不同的节段性枕-寰-枢（C0-C1-C2）固定技术的生物力学。方法： 收集6具完整的人类尸体颈段（C0-C5），单皮质螺钉固定枕部，侧块螺钉固定C1，而C2固定技术分为三种：椎板交叉螺钉、椎弓根螺钉、C1-C2经小关节螺钉。C1侧块螺钉在置入C1-C2经小关节螺钉前取出。固定后测量每组结构C0-C2间的活动范围。结果：3种不同的固定技术跟正常脊柱相比活动范围皆缩小。3种固定技术间在屈伸和轴向旋转的活动度上无明显差异。同其他2组相比，C2椎板交叉螺钉组的侧方弯曲活动度有增加的趋势。同椎弓根螺钉组和经小关节螺钉组比较，椎板螺钉组在CT轴位和矢状面图像上远离椎动脉。结论：使用C2椎板交叉螺钉、C2椎弓根螺钉和C1-C2经小关节螺钉进行枕-寰-枢（C0-C1-C2）固定的技术都可以提供相似的生物力学稳定性。与其它2固定技术相比， C2椎板螺钉固定技术损伤椎动脉的风险较少。

The biomechanical comparison of three different fixed techniques for segmental occipitoatlantoaxial

Objective: To compare the biomechanics of three different segmental occipitoatlantoaxial (C0-C1-C2) stabilization techniques. Methods: Six human cadaveric intact cervical spines (C0-C5) were collected.All occiput were fixed by one-side cortex screw、lateral mass screws at C1 and the C2 using 3 different techniques : crossing laminar screws,pedicle screws,C1-C2 transarticular screws. The C1 lateral mass screws were removed before placement of the C1-C2 transarticular screws. Range of motion across C0-C2 was measured. Results: Compared with the normal group, the range of motion across C0-C2 was obviously decreased in all three different fixed techniques. There were no significant differences among the three fixed techniques in flexion/extension and axial rotation. In lateral bending, the technique using C2 crossing laminar screws proved a trend toward increased range of motion compared to the other 2 techniques. Verification on greater distal end to the vertebral artery by CT scans in the crossing laminar screw technique compared to other two techniques. Conclusion: The same biomechanical stability all can be attained by C2 crossing laminar screws, C2 pedicles screws, and C1-C2 transarticular screws. The risk to the vertebral artery by using the C2 crossing laminar screw technique may be less the other techniques .