Duncan N A, Ahmed A M
Department of Mechanical Engineering, McGill University, Montreal, Province of Quebec, Canada.
Spine (Phila Pa 1976). 1991 Sep;16(9):1089-98. doi: 10.1097/00007632-199109000-00014.
This study was done to establish the relevance of axial rotation as a cause of disc degeneration in the lumbar spine and the role of facet asymmetry in the injury mechanism. It previously was shown that facet asymmetry does not affect the axial torque-rotation response of lumbar motion segments. This study, in both an experimental and a finite-element analysis, examined three important points previously not considered for lumbar motion segments subjected to axial torque: 1) the effect of facet asymmetry on the coupled motions; 2) the effect of combined geometric parameters on the segment response; and 3) the effect of facet asymmetry on the annular strains. Three different lumbar-coupling patterns were observed; however, they did not appear to be influenced by facet joint asymmetry. An oblique and flat compression facet may allow an increased motion-segment response, but in general, combined geometric parameters were found to have no effect on segment response. It was concluded that, without facet damage, the right or left side of the disc is not biased by a particular facet geometry to experience unusual levels of stress and strain, either as a result of increased axial rotation or any of the associated coupled motions.
本研究旨在确定腰椎轴向旋转作为椎间盘退变原因的相关性以及小关节不对称在损伤机制中的作用。此前已表明，小关节不对称并不影响腰椎运动节段的轴向扭矩 - 旋转反应。本研究通过实验和有限元分析，考察了此前在承受轴向扭矩的腰椎运动节段中未被考虑的三个要点：1）小关节不对称对耦合运动的影响；2）组合几何参数对节段反应的影响；3）小关节不对称对纤维环应变的影响。观察到三种不同的腰椎耦合模式；然而，它们似乎不受小关节不对称的影响。斜向和平坦的压缩小关节可能会使运动节段反应增加，但总体而言，发现组合几何参数对节段反应没有影响。得出的结论是，在没有小关节损伤的情况下，椎间盘的右侧或左侧不会因特定的小关节几何形状而在轴向旋转增加或任何相关耦合运动导致的应力和应变水平异常方面受到偏向。
