# INTERNAL AND EXTERNAL DEFORMATIONS OF THE LUMBAR DISC

> **NIH NIH R01** · UNIVERSITY OF VERMONT & ST AGRIC COLLEGE · 1988 · $201,299

## Abstract

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.

## Key facts

- **NIH application ID:** 3158665
- **Project number:** 1R01AR038630-01A1
- **Recipient organization:** UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
- **SAM.gov UEI:** Z94KLERAG5V9
- **Principal Investigator:** MARTIN H KRAG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $201,299
- **Award type:** 1
- **Project period:** 1988-02-01 → 1992-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3158665

## Citation

> US National Institutes of Health, RePORTER application 3158665, INTERNAL AND EXTERNAL DEFORMATIONS OF THE LUMBAR DISC (1R01AR038630-01A1). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3158665. Licensed CC0.

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