Impact response of the intervertebral disc in a finite-element model
Impact response of the intervertebral disc in a finite-element model
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DOI：
10.1097/00007632-200010010-00003
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发表时间：
2000-10-01
期刊：
影响因子：
3
通讯作者：
Goel, VK
中科院分区：
文献类型：
--
作者：
Lee, CK;Kim, EY;Goel, VK
研究设计。利用椎间盘三维非线性多孔弹性有限元模型，分析冲击载荷对脊柱节段的生物力学影响。目的，预测不同冲击持续时间/加载速率下椎间盘内压力、动态刚度、终板区域应力等生物力学参数的变化以及脊柱的减震机制，并探讨加载速率与椎体骨折电位之间的关系。背景数据总结。使用实验方案来辨别影响持续时间的作用是不切实际的。分析研究更适合这个目的。然而，以前的运动段多孔弹性有限元模型主要处理蠕变现象。方法。修改了三维 L3-L4 运动段有限元模型，以纳入椎间盘、终板和松质芯的多孔弹性特性，从而模拟减震现象。在 3 kN 恒定最大压缩冲击载荷的可变冲击持续时间下分析结果。对于较短的冲击持续时间和给定的F-max，与长冲击持续时间的情况相比，产生相对较高的松质芯压力，尽管脉冲量增加。相比之下，无论冲击持续时间如何，核中都会产生相对恒定的孔隙压力。脊柱节段刚度随冲击持续时间的变化表明，对于较短的冲击持续时间，高动态刚度增加了脊柱节段抵抗冲击载荷的稳定性。然而，椎体和终板内应力的相应增加可能会产生骨折。结论。有限元技术用于解决冲击持续时间在对脊柱运动节段产生创伤中的作用。在模型的限制内，结果表明在较短的冲击持续时间条件下很可能发生断裂。根据该区域的强度，骨折可能始于终板区域或皮质壳的后壁。核压力与撞击持续时间无关，仅取决于撞击力的大小。
Study Design. A three-dimensional nonlinear poroelastic finite-element model of a vertebra disc was used to analyze the biomechanical effects of impact loading on the spinal segment.Objectives, To predict changes in biomechanical parameters such as intradiscal pressure, dynamic stiffness, stresses in the endplate region, and the shock-absorbing mechanism of the spine under different impact duration/loading rates, and to investigate the relation between the rate of loading and the fracture potential of the vertebral body.Summary of Background Data. It is not practical to discern the role of impact duration using experimental protocols. Analytical studies are better suited to this purpose. However, previous poroelastic finite-element models of the motion segments have dealt mostly with creep phenomena.Methods. A three-dimensional, L3-L4 motion-segment, finite-element model was modified to incorporate the poroelastic properties of the disc, endplate, and cancellous core, and thus simulate the shock-absorbing phenomena. The results were analyzed under variable impact durations for a constant maximum compressive impact load of 3 kN.Results. For a shorter impact duration and a given F-max, relatively high cancellous core pressure was generated as compared with a case of long impact duration, although the amount of impulse was increased. In contrast, relatively constant pore pressures were generated in the nucleus regardless of the impact duration. The changes in spinal segment stiffness as a function of impact duration indicated that for a shorter duration of impact, high dynamic stiffness increases the stability of the spinal segment against the impact load. However, the corresponding increase in stresses within the vertebral body and endplate may produce fractures.Conclusions. The finite-element technique was used to address the role of impact duration in producing trauma to the spinal motion segment. Within the limitations of the model, the results suggest that fractures are likely to occur under shorter impact duration conditions. Depending on the strength of the region, a fracture may be initiated in the endplate region or the posterior wall of the cortical shell. The nucleus pressure is independent of the impact duration and depends only on the magnitude of the impact force.