Structural behavior of human lumbar spinal motion segments
Structural behavior of human lumbar spinal motion segments
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DOI：
10.1016/j.jbiomech.2003.10.003
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发表时间：
2004-02-01
影响因子：
2.4
通讯作者：
Stokes, IAF
中科院分区：
文献类型：
--
作者：
Gardner-Morse, MG;Stokes, IAF
本研究的目的是获得线性化的刚度矩阵，并评估人体腰椎在轴向预载荷和流体环境的生理条件下的运动节段的线性和滞后。此外，刚度矩阵以“等效”结构的形式表示，这将使人们深入了解脊柱的结构行为。通过记录施加六个主位移时的力，在六个自由度上测量人尸体腰椎L2-3和L4-5脊柱运动节段的力学性能。每个样本均在0、250和500 N的轴向压缩预载荷下进行测试。位移为4个缓慢循环，前后和侧向位移为0.5mm，轴向位移为+/-0.35mm，侧向旋转为+/-1.5 °，屈伸和扭转旋转为+/-1 °。随着预紧力的增加，梁的刚度、滞回面积（而非损失系数）以及荷载-位移关系的线性度都有显著的增加。完整运动节段的对角和主要非对角刚度项的平均值相对于无预载荷的值显著增加，预载荷为250和500 N时的平均系数分别为1.71和2.11（所有8次测试p < 0.01）。在较高的预载荷下，L4-5的刚度项的一半大于L2-3。在每个预紧力的线性化刚度矩阵表示为一个等效的结构组成的桁架和梁的刚性后偏移，其几何特性随预紧力的变化。这些刚度特性可用于腰椎的结构分析。(C)2003 Elsevier Ltd.保留所有权利。
The objectives of this study were to obtain linearized stiffness matrices, and assess the linearity and hysteresis of the motion segments of the human lumbar spine under physiological conditions of axial preload and fluid environment. Also, the stiffness matrices were expressed in the form of an 'equivalent' structure that would give insights into the structural behavior of the spine. Mechanical properties of human cadaveric lumbar L2-3 and L4-5 spinal motion segments were measured in six degrees of freedom by recording forces when each of six principal displacements was applied. Each specimen was tested with axial compressive preloads of 0, 250 and 500 N. The displacements were four slow cycles of 0.5 mm in anterior posterior and lateral displacements, +/-0.35 mm axial displacement, +/-1.5degrees lateral rotation and +/-1degrees flexion-extension and torsional rotations. There were significant increases with magnitude of preload in the stiffness, hysteresis area (but not loss coefficient) and the linearity of the load-displacement relationship. The mean values of the diagonal and primary off-diagonal stiffness terms for intact motion segments increased significantly relative to values with no preload by an average factor of 1.71 and 2.11 with 250 and 500 N preload, respectively (all eight tests p < 0.01). Half of the stiffness terms were greater at L4-5 than L2-3 at higher preloads. The linearized stiffness matrices at each preload magnitude were expressed as an equivalent structure consisting of a truss and a beam with a rigid posterior offset, whose geometrical properties varied with preload. These stiffness properties can be used in structural analyses of the lumbar spine. (C) 2003 Elsevier Ltd. All rights reserved.