后路椎间融合术后全腰椎模态分析

目的 研究日常生活中振动环境对后路椎间融合术患者的影响。方法 建立正常全腰椎和固定L4～5节段全腰椎有限元模型，在L1上终板添加40 kg质量点，并进行模态分析。结果 与正常全腰椎相比，后路椎间融合术后全腰椎的各阶共振频率均降低，对应振型的主运动也发生改变；术后模型第1、2阶固有频率分别为2.94、3.81 Hz，均接近日常生活中的振动频段；在前3阶振型中，术后模型L2和L3节段后部单元振幅均增大，增大了该部位术后退变的风险，L3～4节段椎间盘振幅明显增大，特别是该椎间盘靠近L3节段的部分，可能会增大其应力和应变，进而加速其退变。结论 基于后路椎间融合术后腰椎的模态分析，研究融合术后腰椎振动特性的变化，为术后患者恢复和健康生活提供一定理论指导。
Objective To study the effect of vibration environments on patients with posterior lumbar interbody fusion in daily life. Methods Finite element models of an intact lumbar spine and a postoperative model with fixed L4-5 segments were established. Subsequently, a 40-kg mass point was applied to the upper end plate of the L1 segment to perform a modal analysis. Results In comparison with an intact lumbar spine, the resonance frequency for each order of the whole lumbar spine was reduced after posterior lumbar interbody fusion, and the primary movement of the corresponding modes were also changed. The first two inherent frequencies of the modal in the fusion model were 2.94 Hz and 3.81 Hz, which were close to the vibration frequencies in daily life. In the first three order vibrations, the mode amplitudes of the posterior elements for the L2 and L3 segments increased in the fusion model, which could increase the risk of postoperative degeneration at such locations. In addition, the vibration amplitude of the intervertebral disc of the L3-4 segments clearly increased, particularly at the part of the disc near the L3 vertebral body, which could lead to increased stress and strain and further accelerate its degeneration. Conclusion sBased on the modal analysis of a lumbar spine after posterior lumbar interbody fusion, the investigation of the vibration characteristics of the postoperative lumbar spine will provide some theoretical guidance for the recovery and healthy life of the patients after the corresponding surgery.