骨质疏松性腰1椎体有限元模型的建立和应力分析

目的:建立不同载荷下骨质疏松性椎体骨折的有限元模型,研究载荷条件与骨折部位的关系,预测骨折方式。方法:将志愿者T12-L2椎体CT数据导入Mimics软件,建立L1椎体有限元模型,然后导入3-Matic软件建立皮质骨和松质骨模型,再导入Ansys Workbench软件,分别赋予骨质疏松材料属性并划分网格。对模型施加五种不同的载荷,模拟椎体骨折。结果:椎体与皮质骨形变一致,皮质骨较松质骨形变值更大(P=0.042<0.05)。所有载荷中,垂直压力产生最大形变值,扭转载荷最小。压缩负荷导致椎体上终板和椎体中心形变最大,方向向下;前屈、后伸和侧弯均导致椎体前柱周围形变最大,向载荷方向形变,也导致椎体高度丢失;扭转导致椎体前缘形变最大。结论:本研究预测在骨质疏松性椎体骨折情况下,椎体皮质骨较松质骨先发生骨折;垂直压力最容易引发椎体骨折;垂直压力可造成椎体压缩骨折;前屈、后伸和侧弯均可造成椎体爆裂骨折;扭转可造成椎体前缘骨折。

The Establishment of Finite Element Model and Stress Analysis of Osteoporotic Lumbar Vertebrae 1

Objective: Establish a finite element model of osteoporotic vertebral fracture under different loads, to study the relationship between load conditions and fracture site, and to predict fracture mode. Methods: The CT data of the volunteers’ T12-L2 vertebral body were imported into Mimics software, L1 vertebral body finite element model was established, and then the cortical bone and spongy bone models were imported into 3-Matic software, and then imported into Ansys Workbench software, which were respectively assigned with osteoporosis material properties and divided into grids. Five different loads were applied to the model to simulate vertebral fractures. Results: Vertebral body deformation was consistent with cortical bone, and cortical bone deformation was larger than cancellous bone(P=0.042<0.05). Among all the loads, the vertical pressure generates the maximum deformation value and the torsion load is the minimum. The compression load results in the maximum deformation of the upper endplate and the center of the vertebral body in a downward direction;The anterior flexion, posterior extension and lateral curvature all result in the maximum deformation around the front column of the vertebral body, and the deformation towards the direction of the load, which also results in the loss of the height of the vertebral body. The deformation of the leading edge of the vertebral body is caused by torsion. Conclusion: This study predicted in the case of osteoporotic vertebral fracture, vertebral cortical bone fracture occurred earlier than cancellous bone;vertical pressure is most likely to cause vertebral fracture;vertebral compression fracture can be caused by vertical pressure;Vertebra burst fracture can be caused by anterior flexion, posterior extension and lateral curvature. Torsion can cause a fracture of the anterior edge of the vertebral body.