寰椎齿状突人工关节置换的生物力学研究

Biomechanical study of atlas odontoid process replacement

[目的]测试寰椎齿状突人工关节置换后寰枢椎的稳定性和功能。[方法]将10例新鲜的成人头颈部标本制备成生物力学实验模型,对每一标本分别测定完整状态、减压术后、人工关节置换术后以及疲劳实验后4种状态下的运动范围、中性区和刚度。[结果]减压术后,在前屈、后伸、左右侧屈及左右旋转等方向较完整状态运动范围、中性区明显增大(P<0.05),而刚度则显著减弱(P<0.05);人工关节置换术后及疲劳实验后与减压术后相比前屈、后伸、左右侧屈及左右旋转的运动范围和中性区明显减小(P<0.05),刚度显著增强(P<0.05);人工关节置换术后及疲劳实验后与完整状态相比前屈、后伸、左右侧屈的运动范围和中性区明显减小(P<0.05),刚度显著增强(P<0.05),与完整状态相比左右旋转的运动范围无显著差异(P>0.05),中性区增大(P<0.05),刚度减小(P<0.05)。[结论]实验证实作者设计、制造出的人工寰椎齿状突关节在形态学和动力学两方面进行仿生,具有置放稳定、操作简便、不易造成副损伤以及低磨损等特点,对以往齿状突切除、脊髓减压后需要使用前路或(和)后路寰枢椎融合的患者,提供了另一种术式的选择。

[Objective] To investigate the stability and function of atlantoaxial segment after atlas odontoid process artificial joint replacement. [ Method] Ten fresh adult human head and neck specimens were chosen for biomechanical models. The range of motion （ ROM ） , neutral zone（NZ） and stiffness under intact state, post - decompression, post-replacement surgery and post - fatigue were measured respectively. [ Result] After decompression, ROM, NZ and stiffness in flexion, extension, right and left lateral bending, and fight and left axial rotation increased significantly （ P 〈 0.05 ） than those in contact state. ROM and NZ in replacement group and post - fatigue group decreased significantly （ P 〈 0.05 ） in flexion, extension, and lateral bending than those in intact state group, but stiffness increased significantly （P 〈 0.05 ）. ROM in axial rotation showed no significant difference （ P 〉 0.05 ） than that in intact state group. [ Conclusion ] Artificial atlantoaxial joint in this study has been proved to have biomechanical significance in morphology and dynamic. It has advantages of stable replacement, simple operation, less injury and low wear characteristics. It provides a new choice for the atlantoaxial fusion of anterior or posterior approach.