The Significance of Non-Uniform Endplate Thickness on Diffusion To the Intervertebral Disc

INTRODUCTION: Understanding the mechanism which leads to low back pain is a critical step to developing novel preventative strategies and therapeutic interventions that target this debilitating disease. Epidemiologic data indicate a strong correlation between incidence of low back pain and repeated mechanical loading of the spine. Low back pain also correlates with degeneration of the intervertebral disc and with sclerotic changes to the subchondral bone and vertebral endplates. While the exact mechanism remains unknown, one of the two general theories by which mechanical loading leads to painful intervertebral disc degeneration is via changes in diffusion of small molecules to the disc through the vertebral endplates, particularly in the region of the central nucleus. If the endplates and subchondral bone respond to the mechanical stimuli and become sclerotic, this can impede diffusion to and from the disc, subsequently creating ischemia and hypoxia. This results in catabolic activity that ultimately causes destruction of the matrix, loss of proteoglycans, and structural failure of the disc.