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Research on Constitutive Laws of Lumbar Intervertebral Disc with Biphasic Thoery

双相理论研究腰椎间盘的本构规律

基本信息

批准号：
08458279
负责人：
TADANO Shigeru
金额：
$ 4.61万
依托单位：
HOKKAIDO UNVIERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

The aim of this research project is to develop the constitutive laws of lumbar intervertebral discs by applying the biphasic theory, and to simulate the visco-elastic deformation of the disc using the computational mechanics. The following results were obtained :(1) To analyze mechanically the visco-elastic deformation of the lumbar intervertebral disc, the constitutive equations were formulated from by the biphasic theory, and was developed a modeling method represented the mechanical behavior of inner tissues in the disc : nucleus pulposus, annulus fibrosus and the trangeint region between them. The computational analysis using the finite element method could simulate the creep deformation of the intervertebral disc taking time dependency into account.(2) The method to measure the intradiscal pressure response to low-frequency vibration loading was developed using a calf lumbar spinal segment which is two vertebral bodies and one intervertebral disc. The experiment was carried out in a physiological saline solution to simulate in vivo conditions. Prior to the vibration test, the equilibrium pressure was measured under the constant load during I hour. The amplitude and frequency were controlled after the intradiscal pressure reached the equilibrium.(3) The macroscopic constitutive law of the lumbar intervertebral disc to be described mathematically with the finite deformation theory. Mechanical behaviors of the cadaveric lumbar disc obtained from continuous cyclic compression-tension test and continuous cyclic axial torsion test were formulated by the constitutive equation with a semi-circular shaped model. These equations were taken with or without nucleus pulposus into account. It was also confirmed that forward-backward bending behavior of the disc could be simulated numerically from these equations.

本研究的目的是应用双相理论建立腰椎间盘的本构规律，并利用计算力学模拟腰椎间盘的粘弹性变形。结果表明：(1)为了对腰椎间盘的粘弹性变形进行力学分析，利用双相理论建立了本构方程，并建立了椎间盘内部组织：髓核、纤维环及其之间的三角区域力学行为的建模方法。采用有限元方法进行计算分析，可以模拟考虑时间依赖性的椎间盘蠕变。(2)以小腿腰椎节段为研究对象，建立了测量低频振动载荷下腰椎间盘内压力响应的方法。实验在生理盐水溶液中进行，以模拟体内条件。在进行振动试验之前，测量了在恒载作用下1小时的平衡压力。在椎间盘内压力达到平衡后，控制振幅和频率。(3)用有限变形理论对腰椎间盘宏观本构规律进行数学描述。通过连续循环压张试验和连续循环轴向扭转试验得到的尸体腰椎间盘的力学行为，用半圆型模型的本构方程表示。这些方程在有无髓核的情况下都是考虑的。并证实了用这些方程可以数值模拟圆盘的前向后弯曲行为。