The proposed research program is designed to verify the hypothesis that facet load is transmitted from one vertebra to the next by having the inferior facet bottom out on the pars interarticularis of the vertebra below. It is further hypothesized that the facets rotate relative to each other under load, causing the joint capsule to be stretched. Measurements are proposed to verify this second hypothesis.
The specific aims of the research program are: 1. To develop a loading system which can simulate extensor muscle action and apply flexion loads on a motion segment. 2. To measure contact pressure of the facets on the pars interarticularis. 3. To measure motion (translation and rotation) of the facets during application of axial load to the lumbar spine. 4. To use the three-dimensional finite element model of a lumbar motion segment to simulate the motion of the facets due to gravitational and muscular loads. A combined analytical and experimental approach is proposed because the experimental data acquired from cadaveric specimens cannot reflect the effects of muscular action and the mathematical model of a motion segment is an essential surrogate at this stage of the investigation of low back pain. Recent data on facet joint stiffness indicate that muscular tension, especially of the spinal extensors, can play a significant role in the distribution of load borne by the disc and the facets.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM020201-11
Application #
3269951
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1976-06-01
Project End
1987-11-30
Budget Start
1985-12-01
Budget End
1986-11-30
Support Year
11
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Wayne State University
Department
Type
DUNS #
City
Detroit
State
MI
Country
United States
Zip Code
48202
Cavanaugh, J M; el-Bohy, A; Hardy, W N et al. (1989) Sensory innervation of soft tissues of the lumbar spine in the rat. J Orthop Res 7:378-88
el-Bohy, A; Cavanaugh, J M; Getchell, M L et al. (1988) Localization of substance P and neurofilament immunoreactive fibers in the lumbar facet joint capsule and supraspinous ligament of the rabbit. Brain Res 460:379-82