计算机模拟椎体成形对邻近节段力学影响的有限元分析

背景：椎体成形后邻近椎体再骨折的原因，是骨质疏松的发展过程，或是骨水泥增强、椎体成形干预造成的？ 目的：用有限元方法观察椎体成形对相邻椎体的力学影响，分析相邻椎体继发骨折的病因。 方法：利用MIMICS软件，对1例T₁₂骨质疏松性椎体压缩骨折患者CT图片进行预处理后导入ABAQUS软件中建立T10~L2三维有限元模型，模拟经椎弓根单侧和双侧入路椎体成形，设置0.3，1.0，4.0 MPa 3种轴向载荷进行生物力学分析。 结果与结论：成功建立了椎体成形前后的三维有限元模型。当轴向压力以0.3，1.0，4.0 MPa增加后，椎间盘、软骨终板和椎体整体的应力也成比例增加。椎体成形后增强椎体(T₁₂)上、下终板骨水泥注入侧的应力增强区域范围减少，所受最大应力明显减少；邻近椎间盘及椎体的应力分布无明显变化；T₁₂相邻椎体(T₁₁、L₁)及远端椎体(T₁₀、L₂)所受最大应力无明显改变。提示椎体成形后引起上下相邻椎体继发骨折的并发症可能和生物力学结果改变无关。

Biomechanical effect of simulative percutaneous vertebroplasty on adjacent vertebras: A finite element analysis about thoracolumbar osteoporotic vertebra compression fracture

BACKGROUND:Is adjacent vertebral fracture following percutaneous vertebroplasty (PVP) a development process of osteoporosis or caused by enhanced bone cement and PVP? OBJECTIVE:To explore the biomechanical effects on adjacent vertebras of thoracolumbar osteoporotic vertebra compression fracture (OVCF) after simulative PVP by using finite element analysis. METHODS:T₁₀-L₂ segment data were obtained from CT scans of an old female with single T₁₂ OVCF. A three-dimensional finite element model of thoracolumbar spine (T₁₀-L₂) and simulative PVP models (via single and double transpedicular approach) were built in the Mimics and the ABAQUS software. The stress on the vertebra, disc and endplate under axial pressure (0.3, 1.0, 4.0 MPa) were analyzed. RESULTS AND CONCLUSION: The three-dimensional finite element models of thoracolumbar OVCF and simulative PVP models were successfully built. The stresses were increased as axial pressure increased. In the model of simulative PVP, the stress augmentation scope on adjacent vertebras and discs did not increase. The maximum Von Mises stress on adjacent vertebras had no significant changes. Postoperative adjacent vertebral fractures after PVP may be poorly related to the changes of biomechanical effects on adjacent vertebras of thoracolumbar OVCF.