Influence of single-level lumbar degenerative disc disease on the behavior of the adjacent segments-A finite element model study
Influence of single-level lumbar degenerative disc disease on the behavior of the adjacent segments-A finite element model study
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DOI：
10.1016/j.jbiomech.2008.11.024
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发表时间：
2009-02-09
影响因子：
2.4
通讯作者：
Andersson, Gunnar B. J.
中科院分区：
文献类型：
--
作者：
Ruberte, Lissette M.;Natarajan, Raghu N.;Andersson, Gunnar B. J.
当前的研究调查了邻近椎间盘退变发展的机械预测因素。修改了腰椎的 3D 有限元模型，以模拟 L4-L5 椎间盘的两个级别的退变。通过几何形状和材料特性的变化来模拟退化。所有模型均使用混合协议在三个主要运动方向上承受 800 N 的从动件预载和力矩载荷。退变导致退变椎间盘上方和下方节段的负载和运动模式发生变化。在退变椎间盘上方的水平 (L3-L4)，由于中度退变，运动在侧向弯曲时增加了 21%，在轴向旋转时增加了 26%，在屈曲/伸展时增加了 28%。在退变椎间盘下方的水平 (L5-S1)，由于中度退变，运动仅在侧向弯曲时增加 20%。随着所有载荷方向的退化进展，L3-L4 和 L5-S1 段都显示环空中最大 von Mises 应力和剪切应力单调增加，预计 L3-L4 处会延伸。在轴向旋转期间，在 L5-S1 水平处观察到最显着的应力增加，最大剪切应力增加了近 10 倍，最大 von Mises 应力增加了 103%。 L5-S1 段还显示出所有加载方向的小面接触力随着退化而逐渐增加。对于尾侧或头侧相邻节段的任何加载方向，核压力均未显着增加。结果表明，单节段变性会增加邻近节段受伤的风险。 (C) 2008 Elsevier Ltd. 保留所有权利。
The current study investigated mechanical predictors for the development of adjacent disc degeneration. A 3-D finite element model of a lumbar spine was modified to simulate two grades of degeneration at the L4-L5 disc. Degeneration was modeled by changes in geometry and material properties. All models were subjected to follower preloads of 800 N and moment loads in the three principal directions of motion using a hybrid protocol. Degeneration caused changes in the loading and motion patterns of the segments above and below the degenerated disc. At the level (L3-L4) above the degenerated disc, the motion increased due to moderate degeneration by 21% under lateral bending, 26% under axial rotation and 28% under flexion/extension. At the level (L5-S1) below the degenerated disc, motion increased only during lateral bending by 20% due to moderate degeneration. Both the L3-L4 and L5-S1 segment showed a monotonic increase in both the maximum von Mises stress and shear stress in the annulus as degeneration progressed for all loading directions, expect extension at L3-L4. The most significant increase in stress was observed at the L5-S1 level during axial rotation with nearly a ten-fold increase in the maximum shear stress and 103% increase in the maximum von Mises stress. The L5-S1 segment also showed a progressive increase in facet contact force for all loading directions with degeneration. Nucleus pressure did not increase significantly for any loading direction at either the caudal or cephalic adjacent segment. Results suggest that single-level degeneration can increase the risk for injury at the adjacent levels. (C) 2008 Elsevier Ltd. All rights reserved.