Effect of Load History on Ovine Intervertebral Disc Biomechanics

Abstract

Loading of the intervertebral disc (IVD) alters biomechanical properties by modifying fluid distribution in the nucleus pulposus -changing hydrostatic pressure and tissue response- during force transmission along the spine. This study combines pressure, vertical displacement, and radial bulge measurements to assess biomechanical function during healthy and adverse loading of ovine lumbar motion segments. High compressive loads and simultaneous transient exertions, representative of obesity or other high-load lifestyles, are expected to limit fluid recovery and inhibit IVD biomechanical function compared to low compressive load controls with similar transient exertions. Specifically, the adverse group will (1) lose the ability to generate intradiscal pressures equivalent to control discs at equal loads and (2) exhibit a greater degree of deformation and bulge during comparable loading. This study contributes a greater understanding of the effects of load on IVD health. Findings may inform future efforts to preserve disc biomechanics and reverse IVD loss of function.