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中文核心期刊

瞬态载荷下L4/L5椎间盘内流固耦合效应

EFFECT OF FLUID-STRUCTURE INTERACTION OF L4/L5 INTERVERTEBRAL DISC UNDER TRANSIENT LOADS

  • 摘要: 中医正脊治疗通过对腰椎施加瞬态拉伸和旋转来治疗腰椎间盘退变, 本文采用考虑流固耦合效应的数值模拟研究其生物力学机制. 通过实验测量和文献调研, 确定了合理的拉伸和旋转的载荷参数; 发展了使用人体断层扫描图像结合解剖学数据建立详细腰椎几何模型的方法; 将松质骨、终板、椎间盘考虑为多孔弹性介质, 其他组织考虑为线性弹性介质, 进而建立了考虑生物组织中流固耦合效应的物理模型; 通过数值模拟得到了不同瞬态载荷及其组合作用下椎间盘内应力−应变与流体流动的变化规律. 研究发现, 瞬态载荷通过改变L4/L5椎间盘基质应力和髓核内外压力梯度, 在髓核中产生流体流动; 拉伸加载引起流体先流出髓核、再流入髓核, 产生含水量变化; 顺时针旋转加载在髓核左右产生相反的流动, 髓核右侧的含水量变化较左侧大. 本研究所采用的方法为流动过程相关的人体椎间盘退变病理生理机制研究提供了新的方法, 为中医正脊研究提供科学化思路, 也为相关的力学-生物学耦合研究和髓核再生的基础研究提供了一个切入点.

     

    Abstract: The spine manipulation of traditional Chinese medicine treats the degeneration of the lumbar intervertebral disc by applying transient distraction and rotation forces on the lumbar spine. In this paper, numerical simulation considering fluid-structure interaction is used to study the underlying biomechanical mechanisms. Through experimental measurement and literature research, reasonable parameters of distraction and rotation loads have been determined. A method is developed to build a detailed geometric model of lumbar spine, which uses data from computed tomography scans of human body and anatomical knowledge. Cancellous bones, endplates, and intervertebral discs are considered as poroelastic materials, while others are considered as linear elastic materials, in order to consider the effect of fluid-structure interaction in biological tissues considered here. Through numerical simulations, the stress, strain and fluid flow in the intervertebral disc under transient loads and their combination are obtained. It is found that the transient load generates fluid flow in the nucleus pulposus by changing the stress of the solid matrix of the L4/L5 intervertebral disc and producing pressure gradient across the nucleus pulposus. Distraction causes the fluid to flow out of the nucleus pulposus first and then flow into the nucleus pulposus to produce a change of water content. Under clockwise rotation, opposite flow processes occur on left and right sides of the nucleus pulposus. Water content on the right side of the nucleus pulposus changes greater than the left side. The method used in this research provides a new method for the study of the pathophysiological mechanism of human intervertebral disc degeneration related to the flow process. This method also provides a pathway to make the spine manipulation of traditional Chinese medicine scientific. An entry point is provided additionally for the related study of mechanical and biological coupling study, as well as the basic research of nucleus pulposus regeneration.

     

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