INTERNAL AND EXTERNAL DEFORMATIONS OF THE LUMBAR DISC

椎间盘对正常脊柱和 功能，以及各种重要的脊柱 异常，其中一个重要的例子是腰痛： 有250万人腰部受伤， 美国的残疾人;腰部损伤总赔偿 1978年的费用估计为27亿美元。 对我们至关重要 这个问题的理解是生物力学的 椎间盘 我们建议通过以下方式促进这一谅解： 测量盘的内部变形， 相邻椎骨之间的运动。 没有以前的定量 关于内部盘变形的工作已经报道， 这个实验室的初步工作。 拟议工作的主要目标如下： 1. 对于人体腰椎间盘内部， 描述生物力学行为（位移分布 和核内压力）， 椎间移位（压缩、屈曲、伸展）， 4种不同的椎间盘状态（正常完整，正常 瓣环切开术，正常去核，退化完整），使用 未防腐的尸体离体运动节段。 使用的测量技术包括a）小金属珠 通过一种特殊的方法， 立体毒性器械和皮下注射针，B）矢状面X- 射线记录珠位移，c）专门设计的霍尔- 效应传感器以记录沿着所述表面的周边的应变沿着， 盘，d）从核中心的压力记录 e）MTS机器，以施加受控的 运动节段的上椎骨上的位移， 来记录合力。 2. 对于这4种盘状态中的每一种，为了比较实验结果， 测量位移与四个预测的位移 二维有限元模型（各向同性，正交各向异性，流体静力学， 多孔弹性的）。 每个模型都将使用 单个椎间盘标本和椎骨位移 强加于他们。 通过比较实验数据和模型预测 关于这种关系，可以检验几个假设 型号类型和磁盘状态之间的关系。

The intervertebral disc is important for both normal spine function, as well as for a variety of significant spine abnormalities, an important example of which is low back pain: there are 2.5 million low back injured and 1.2 million low back disabled adults in the U.S.; low back injury total compensation costs were estimated to be $2.7 billion in 1978. Critical to our understanding of this problem is the biomechanics of the intervertebral disc. We propose to further this understanding by measuring the internal deformations of the disc as a result of motion between adjacent vertebrae. No previous quantitative work has been reported on internal disc deformations other than preliminary work from this laboratory. The major goals of the proposed work are as follows: 1. For the interior of human lumbar intervertebral discs, to describe the biomechanical behavior (displacement distribution and intranuclear pressure) produced by each of 3 controlled intervertebral displacements (compression, flexion, extension), for each of 4 different disc states (normal intact, normal with annulotomy, normal denucleated, and degenerated intact), using unembalmed cadaveric excised motion segments in vitro. The measurement techniques used include a) small metallic beads implanted in a regular array within the disc, by means of a special stereotoxic instrument and hypodermic needle, b) sagittal view x- rays to record bead displacements, c) specially-designed Hall- effect transducers to record strain along the periphery of the disc, d) pressure recording from the center of the nucleus pulposus, and e) an MTS machine to impose controlled displacements upon the upper vertebra of the motion segment and to record the resulting forces. 2. For each of these 4 disc states, to compare the experimentally measured displacements to those displacements predicted by four 2-D finite element models (isotropic, orthotropic, hydrostatic, poroelastic). Each model will use as input the actual geometry of the individual disc specimens and the vertebral displacements imposed upon them. By comparing the experimental data and the model predictions several hypotheses may be tested concerning the relationship between model type and disc state.