齿状突切除术后前路与后路C1~C2经关节螺钉内固定的生 物力学分析

目的 比较齿状突切除术后前路与后路C1~C2经关节螺钉内固定的生物力学特点，为临床选择前路与后路内固定治疗方案提供生物力学依据。方法 基于前期已构建的全颈椎有限元模型，进一步构建齿状突切除模型，继而在齿状突切除模型中分别构建前路C1~C2内固定模型及后路C1~C2内固定模型，在ABAQUS 6.12.-1软件中计算手术模型各个节段前屈-后伸、左右旋转及左右侧弯的活动度及内固定应力情况。结果 齿状突切除造成C1~C2节段前屈活动度增加幅度达55%，后伸活动度增加128.2%。前路与后路在C1~C2节段的内固定效果基本相同，均可明显限制C1~C2节段的活动度，使其处于相对固定的状态。前路及后路 C1~C2内固定最大应力均位于前屈方向。结论 齿状突切除会明显降低C1~C2节段的稳定性，前路或后路C1~C2经关节螺钉内固定均可明显限制C1~C2的活动度。前路与后路经关节螺钉内固定手术对C1~C2固定效果基本相同，但术后应尽量避免过度的前屈。齿状突切除后直接前路行C1~C2经关节螺钉内固定减少变换体位带来的风险，相对方便直接。

Biomechanical analysis of anterior and posterior C1~C2 articular screw internal fixation after odontoidectomy

Objective To compare the biomechanical characteristics of anterior and posterior C1~C2 articular screw fixation after odontoidectomy in order to provide a biomechanical basis for clinical selection of anterior and posterior internal fixation treatment options. Methods Based on the finite element model of the whole cervical spine that had been constructed in the previous study, the odontoid process resection model was further constructed, and then the anterior C1~C2 internal fixation model and the posterior C1~C2 internal fixation model were constructed in the odontoid process resection model. ABAQUS 6.12.-1 software was used to calculate the range of motion and internal fixation stress of each segment of the surgical model in flexion-post extension, left-right rotation and left-right scoliosis. Results Odontoid resection caused a 55% increase in the flexion and an increase of 128.2% in the extension of C1~C2 segment. The anterior approach and the posterior approach have basically the same internal fixation effects on the C1~C2 segments, and both can obviously limit the mobility of the C1~C2 segments and made it in a relatively fixed state. The maximum stress of anterior and posterior C1~C2 internal fixation was in the direction of flexion. Conclusions Odontoid resection can significantly reduce the stability of C1~C2 segment, and both anterior and posterior C1~C2 internal fixation with articular screws can significantly limit the motion of C1~C2 segment. Anterior and posterior transarticular screw internal fixation surgeries have basically the same effect on C1~C2 fixation. Patients should try to avoid excessive forward bending after the surgery. C1~C2 internal fixation with articular screws directly reduces the risk of changing positions after resection of the odontoid process, which is relatively convenient and direct.