破坏载荷下椎间盘对胸腰段脊柱应力分布影响的研究

目的：对比正常与退变椎间盘在破坏载荷下对胸腰段脊柱应力分布的影响，探讨其生物力学背景及临床意义，为临床诊断及治疗提供理论依据。方法：用三维有限元法建立正常及退变椎间盘的胸腰段脊柱活动节段的力学模型，并对其在垂直压缩，屈曲压缩，屈曲分离三种外加载荷下的应力分布进行对比分析。结果：垂直压缩及屈曲压缩载荷下，正常的椎间盘的胸腰段脊柱活动节段显示椎体上，上终板的中央及松质骨邻近终板的中央部位应力值最高，椎间盘纤维环的后外侧应力集中；退变椎间盘的胸腰段脊柱显示椎体松质骨的应力分布相对平均，邻近终板的中央部分应力水平减低，周边部分水平相应上升，椎间盘纤维环的后侧应力集中；屈曲分离载荷下，退变椎间盘的胸腰段脊柱与正常相比，椎体皮质骨，松质骨，终板及纤维环应力水平有所降低，后部结构的应力水平相应上升。结论：正常与退变椎间盘对破坏载荷下胸腰段脊柱应力分布的影响明显不同，椎间盘退变后载荷的传递方式发生了改变。

Study of influence of intervertibral disc on the stress distribution of thoraco-lumbar vertebrae with destructive load

Objective To compare influence of normal and degenerative intervertibral disc on stress distribution of thoracolumbar vertebrae with destructive load,to explore their biomechanical background and clinical significance and to provide theoretical basis for clinical diagnosis and treatment.?Methods Mechanical model of thoraco lumbar motion segment of normal and degenerative disc was built with three dimensional finite element method and the three kinds of stresses of vertical compression,compressive flexion and distractive flexion were analyzed comparatively.?Results With vertical compressive and compressive flexion load,thoraco lumbar motion segment of normal disc showed that the central part of upper and lower end plates of vertebrae and the central part of the trabecular bone adjacent to the end plate were loaded with the most intensive stresses, meanwhile,stress was concentrated on the posterior lateral part of annulus fibrosuses;?in degenerative disc the stress distribution of trabecular bone was average relatively ,the stresses of central part of it adjacent to end plate were lowered,while at the same time ,the stresses of peripheral part of it were elevated relatively; with distraction flexion load,comparing thoraco lumbar vertebrae degenerative disc with that of normal disc,the stresses of cortex bone, trabecular bone,end plate and annulus fibrosus were lowered,meanwhile, the stresses of the posterior structure of vertebral body were elevated relatively.?Conclusion It was significantly different for influence of normal and degenerative disc on the stress distribution of thoraco lumbar vertebrae with destructive load.The way of transference of load was changed after disc degeneration.