青少年特发性侧凸脊柱的动态特性

目的 基于人体脊柱侧凸CT图像建立胸椎至骶椎T1～S三维有限元模型，并研究模型的动力学特性。方法 采用轴向压缩和剪切加载方式验证所建立的侧凸脊柱模型，验证结果与前人实验数据非常吻合。利用有限元软件ABAQUS对侧凸脊柱进行模态和稳态分析，并提取稳态分析在5、10 Hz振动频率下模型的动态响应。结果 模态分析提取前4阶模态，前2阶模态的固有频率分别为1.097、1.384 Hz，振型分别为屈伸和侧弯。第3、4阶模态固有频率分别为5.688、28.090 Hz，振型分别为垂直振动和绕竖直轴扭转。稳态分析中在模态固有频率附近出现振幅峰值，而且脊柱侧凸段椎体的平均振幅要明显大于其他节段椎体的平均振幅。在5、10 Hz振动频率下，应力主要集中在脊柱侧凸节段的凹侧和凸侧以及侧凸节段的椎间盘上，且分布不均匀。结论 脊柱侧凸患者的侧凸节段是脊柱的薄弱环节，在振动环境中更容易受到损伤，应尽量避免处于振动的环境中，特别是对自身较为敏感的频率范围。研究结果为侧凸患者的康复治疗、防护、临床病理研究提供方法性辅助和力学分析依据。
Objective To establish the three-dimensional (3D) finite element (FE) model of thoracolumbosacral T1-S spine based on the computed tomography (CT) images of patients with scoliosis and study its dynamic characteristics. Methods The established scoliotic model was validated by axial compression and shear loading, and the predicted responses were in good agreement with the experimental data. The modal and harmonic analyses were performed using the ABAQUS software, and during the harmonic analysis, the dynamic response of the model was collected at frequencies 5 Hz and 10 Hz. Results From the modal analysis, the first fourth-order modal was extracted. The first- and second-order resonant frequencies of the model were 1.097 Hz and 1.384 Hz, respectively, and the vibration mode was longitudinal bending and lateral bending, respectively. The distribution of the second- and third-order modal resonant frequencies were 5.688 Hz and 28.090 Hz, and the vibration mode was vertical vibration and twisting around the long axis, respectively. The peak amplitude in the harmonic analysis appeared near the modal frequencies, and the average amplitude of vertebral body of the lateral convex segment was larger than that of other segments of the scoliotic spine. Under the vibration frequencies of 5 Hz and 10 Hz, the stress inhomogeneously concentrated on the concave and convex sides of the segments of the vertebral deformity as well as on the intervertebral disc. Conclusions The segments of the spinal deformity in patients with scoliosis were the weak links of their spines and more vulnerable to damage in a vibrating environment. Patients with scoliosis should avoid a vibrating environment, particularly in a sensitive frequency range. The research outcomes provide methodological assistance and mechanical analysis references for the protection, rehabilitation treatment, and clinical pathological studies of patients with scoliosis.