Objective: To evaluate effect two internal fixations for thoracolumbar fracture. By using finite element analysis method (FEM), and t to provide theoretical support for its clinical application. Methods A youth volunteer(male, aged 23)without chronic low back pain and trauma of thoracolumbar was chosen. We use Dicom datas and Simple ware software to built a 3-D finite element model to mimic the fracture of T12-L2 and LI vertebra' then two therapy approaches of posterior short segment internal fixation(PF), and transvertebral pedicle screws internal fixation were performed by 3-D finite element model. These two models were put intoAbaqus 6.9 finite element program, axial load 750N were loaded, respectively to study the corresponding stress and straining. Von Mises stress on the vertebral body and implant were calculated and load-displacement curve were obtained in the two models. Results: The largest stress was measured in the screw root. The stress in the six-screw group was smaller than that in the four-screw group (P <0.05). Conclusions: Vertical compression loadings were performed, There was a significant difference in stress distributions with condyle position between six-screw group and the four-screw group. It is indicated that it can be optimized to reduce the failure of internal fixation with pedicle screws in injured level.%目的:运用有限元分析的方法,探讨两种不同椎弓根螺钉内固定治疗胸腰段椎体压缩骨折的应力情况,为临床选择有效的内固定方法提供理论依据.方法:选取一无慢性腰背痛及胸腰椎外伤史的青年志愿者,利用CT扫描的Dicom数据图像和Simpleware5.0软件建立T12-L2椎体三维模型,模拟L1椎体骨折,并分别模拟后路短节段椎弓根钉固定(PF)和联合伤椎置钉固定两种治疗方法,将两种模型分别导入Abaqus6.9有限元分析软件,加载750N压力,模拟人胸腰部正常生理压缩状态下,比较两种模型在不同生理活动下两种方法固定后椎体结构和内固定器械的应力分布情况.结果:两组固定模式各种载荷下的应力均集中在螺钉根部.伤椎置6钉固定组螺钉应力较跨节段4钉固定组小(P＜0.05).结论:在压缩状态下,短节段固定组的应力明显增加,与伤椎置钉组螺钉相比具有统计学差异；而连接棒的应力没有明显改变,二者相比没有统计学差异.因此短节段固定组可能会进一步导致内固定的失效.
展开▼
