A Finite Element Study of the effects of Vibrational Loading on the Fluid Flow Mechanism of the Intervertebral Disc

Low back pain is a clinical and public health problem affecting more than half of the population. Disc degeneration is a major source of low back pain. Long-term exposure to whole body vibration or sedentary work postures may have high association with disc degeneration. It is hypothesized that there is a preferential frequency for vibrational loading, which may increase the efficiency for fluid and nutritional transport of the intervertebral disc. Simulation of lumbar motion is inevitable in order to have a more comprehensive view of the fluid flow effect on disc degeneration. Because of the difficulties to understand the biomechanics of the complicated spinal structures from experimental studies alone, computational model is the alternative to predict the biomechanical parameters such as intradiscal pressure; deformation and fluid flow of the intervertebral disc. Although poroelastic models were developed to study the biomechanical response such as creep and impact effect of the lumbar motion segment (Simon et al., 1985; Argoubi & Shirazi-Adl, 1996; Lee et al., 2000), there is still a lack of detailed models to analyse the fluid flow within the intervertebral disc especially under dynamic loading situation. This paper presents a three-dimensional poroelastic finite element model of the lumbar motion segment developed to study the vibrational response and the associated fluid flow of the intervertebral disc.