Lower back pain (LBP) is a wide-spread, complex and poorly understood issue. In the spine, the disc may be a contributor to LBP based on how it can dictate the displacement response of the spine. This study investigated the creep response to a prescribed stress history of vertebra-disc-vertebra sections of porcine spine. Specimens were exposed to a low-magnitude static compressive hold or a sinusoidal cyclic compression at 4 Hz. In static loading, functional spinal units (FSUs) without the posterior column experience higher strain than those with the posterior column (by approximately a third); in cyclic loading, the overall strain response, with or without the posterior column, is similar. A simple analytical model was fit to the static data and predicted the response of the static loading with the posterior column reasonably well, but it under-predicted the strain for specimens without the posterior column.
Keywords:
Compression; Fatigue; Porcine; Spine; Viscoelasticity