INTERNAL AND EXTERNAL DEFORMATIONS OF THE LUMBAR DISC

间盘对两个正常脊柱都很重要 功能，以及各种重要的脊椎 异常，其中一个重要的例子是下腰痛： 250万人腰背受伤，120万人腰背受伤 美国的残疾成年人；腰背损伤总补偿 1978年的费用估计为27亿美元。对我们的 对这一问题的理解是关节的生物力学 腰间盘。我们建议通过以下方式促进这一理解 测量由于以下原因引起的圆盘的内部变形 相邻椎骨之间的运动。没有以前的数量 已经报道了关于内部盘变形的工作，除了 这个实验室的初步工作。 拟议工作的主要目标如下： 1.对于人类腰间盘内部， 描述生物力学行为(位移分布 和核内压力)分别由3个受控 椎间位移(压缩、屈曲、伸展) 4种不同的椎间盘状态(正常完整、正常 环切术，正常去核，退变完整)，使用 未防腐的身体体外运动节段。 所使用的测量技术包括：a)小金属珠 通过特殊的方式植入盘内的规则阵列中 立体毒性器械和皮下注射针，b)矢状面x- 光线记录珠子位移，c)特别设计的大厅- 效应换能器，以记录沿外围的应变 盘，d)从核中心进行压力记录 Pulposus，以及e)MTS机器，以实施受控 运动节段上椎体的位移和 以记录所产生的力。 2.对于这4种盘状状态中的每一种状态，进行实验比较 测量的位移与由四个人预测的位移 二维有限元模型(各向同性、正交各向异性、流体静力学、 孔弹性)。每个模型将使用的实际几何图形作为输入 单个椎间盘标本与椎体移位 强加给他们的。 通过比较实验数据和模型预测 关于这一关系的几个假设可能会得到检验 在型号类型和光盘状态之间。

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.