颅底凹陷寰枢椎脱位不同材料关节间融合器力学性能的有限元分析

Finite Element Analysis of the Mechanical Properties of Different Materials of Inter-Articular Cage for Basilar Invagination with Atlantoaxial Dislocation

目的:研究颅底凹陷寰枢椎脱位(Basilar invagination with atlantoaxial dislocation, BI-AAD)后路内固定治疗技术中不同材料寰枢椎关节间融合器对颈椎生物力学性能的影响。方法:根据BI-AAD患者寰枢椎侧方关节形态结构,结合临床后路内固定手术方案,建立枕骨–上颈椎植入寰枢椎关节间融合器结合悬臂复位技术的三维有限元模型,分析Ti/PEEK和Ti两种材料的寰枢椎关节间融合器对颈椎寰枢关节稳定性的影响、关节间融合器和C2终板的应力分布特征。结果:Ti/PEEK和纯Ti材料的寰枢椎关节间融合器结合悬臂复位技术治疗BI-AAD后,颈椎在前屈、后伸、侧弯和旋转工况下寰枢椎关节活动度(Range of motion, ROM)较BI-AAD病变模型分别降低了98.76%、97.36%、97.74%、97.97%和99.2%、97.74%、97.74%、98.07%;C2终板、关节间融合器上下撑开壳体和内支撑环的应力峰值均呈现Ti/PEEK材料最低,壳体断裂风险相对较小。结论:Ti/PEEK和纯Ti材料的寰枢椎关节间融合器均可提供BI-AAD手术后椎体的稳定性,Ti/PEEK材料关节间融合器整体结构的应力较小,使沉降风险降低,更为安全可行。

Objective: To investigate the effect of different materials of atlantoaxial inter-articular cage on the biomechanical properties of the cervical spine in the posterior internal fixation technique of basilar invagination with atlantoaxial dislocation (BI-AAD). Methods: Based on the morphological struc- ture of the lateral atlantoaxial joint of BI-AAD patients, a three-dimensional finite element model of occipital-superior cervical implantation of atlantoaxial inter-articular cage combined with cantilever repositioning technique was established, and the effects of Ti/PEEK and Ti inter-articular cage on the stability of the cervical atlantoaxial joint and the stress distribution characteristics of the inter-articular cage and C2 endplate were analyzed. Results: After the treatment of BI-AAD with Ti/PEEK and pure Ti inter-articular cage combined with cantilever repositioning technique, the range of motion (ROM) of the atlantoaxial joint in forward flexion, back extension, lateral bending and rotation in the cervical spine was reduced by 98.76%, 97.36%, 97.74%, 97.97% and 98.07%, respectively, compared with the BI-AAD lesion model. 99.2%, 97.74%, 97.74%, 98.07%;the peak stresses of the C2 endplate, the upper and lower braced shells of the inter-articular cage and the internal support ring showed the lowest Ti/PEEK material, and the risk of shell fracture was relatively small. Conclusions: Both Ti/PEEK and pure Ti inter-articular cage in the atlantoaxial spine provide stability of the vertebral body after BI-AAD surgery. The overall structure of the Ti/PEEK inter-articular cage is less stressed, making the risk of subsidence lower and safer and more feasible.