Jiang Yugang, Sun Xiaojiang, Peng Xiongqi, Zhao Jie, Zhang Kai
School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030, P.R. China.
School of Construction Machinery, Shandong Jiaotong University, Shandong 250000, P.R. China.
Exp Ther Med. 2017 May;13(5):2203-2210. doi: 10.3892/etm.2017.4251. Epub 2017 Mar 22.
The present study investigated the influence of sacral slope (SS) on the biomechanical responses of the lumbar spine under specific physiological conditions. Firstly, based on computed tomography scan images of a 30-year-old healthy male volunteer (SS, 55°), a three-dimensional finite element (FE) model including the L4-S1 segment was established. Flexion, extension, lateral bending and torsion motions were simulated and compared with cadaveric test data in the literature to validate the lumbar spine FE model. The model was then modified with different SS values (40 and 25°) for the same simulations to describe the process of structural compensation. Numerical results showed that with the reduction of SS, the range of motions (ROMs) reduced for flexion and lateral bending, but increased for extension and torsion. For displacement, the maximum magnitudes of L4/5 annulus fibrosus (AF) reduced by 10-25% in flexion, lateral bending and torsion, but less effect was observed for extension with only a 4% drop. Nearly the same displacement distribution appeared on the L5/S1 AF with small changes in the four motions. For the stress field of L4/5 AF, in contrast to flexion, the magnitudes for extension and lateral bending varied markedly, and under torsion the value increased by ~10%. For L5/S1 AF, the stresses changed little under flexion, extension and lateral bending, but strongly declined for torsion by ~71.8%. In conclusion, the present study indicates that the change in SS due to structural compensation affects the biomechanical behavior of the spine structure, and attention should be paid to SS when conducting surgical procedures or selecting intervertebral fusion implants.
本研究调查了在特定生理条件下，骶骨坡度（SS）对腰椎生物力学响应的影响。首先，基于一名30岁健康男性志愿者（SS为55°）的计算机断层扫描图像，建立了一个包含L4-S1节段的三维有限元（FE）模型。模拟了前屈、后伸、侧屈和扭转运动，并与文献中的尸体试验数据进行比较，以验证腰椎FE模型。然后，对该模型进行修改，采用不同的SS值（40°和25°）进行相同的模拟，以描述结构补偿过程。数值结果表明，随着SS的减小，前屈和侧屈的运动范围（ROM）减小，但后伸和扭转的运动范围增加。对于位移，L4/5纤维环（AF）在屈曲、侧屈和扭转时的最大幅度减小了10%-25%，但后伸时影响较小，仅下降了4%。在四种运动中，L5/S1 AF上的位移分布几乎相同，只是有微小变化。对于L4/5 AF的应力场，与前屈相比，后伸和侧屈时的应力幅度变化显著，扭转时的值增加了约10%。对于L5/S1 AF，前屈、后伸和侧屈时应力变化不大，但扭转时应力大幅下降约71.8%。总之，本研究表明，结构补偿导致的SS变化会影响脊柱结构的生物力学行为，在进行手术或选择椎间融合植入物时应关注SS。
