Effects of the ablation of the nucleus pulposus on the vibrational behavior of the lumbosacral hinge

Abstract

This study was designed to investigate the respective damping properties of the annulus fibrosus and nucleus pulposus of the intervertebral disc during propagation of vibration waves through the osteo-ligamento-muscular axis of the spine. The study was conducted on a 8–10 kg deeply anesthetized baboon. In the first surgical phase five accelerometers were implanted in the first sacral vertebra and on the anterior side of the four lower lumbar vertebrae. The bioinstrumented animal was placed in a restraining chair and exposed to narrow-bandwidth (0–100 Hz) 0.16 G RMS random vibration. Once data was recorded, the nuclei pulposi of the studied discs were removed by suction, the surrounding annuli remaining intact. The still deeply anesthetized animal was again exposed to the same 0–100 Hz, 0.16 G RMS vibration. Results were analyzed and their reproducibility was tested on three animals.