Pathophysiology of Axial Low Back Pain

Axial low back pain is a challenging clinical problem affecting a large segment of our population. Degeneration of the spinal motion segment generally begins with the disc. The changes result from breakdown of the disc molecular structure in response to decreased nutrition, inflammatory factors, and metabolic stress. The degenerative disc leads to altered spinal biomechanics and secondary degenerative consequences within the facets and vertebral endplate. Generous sensory innervation in combination with a host of inflammatory signals produced by and in response to deterioration of the spinal motion segment result in the perception of pain from the disc, facets, endplates, and spinal musculature. Disease states and genetic predisposition contribute to both the degenerative process and the development of pain. Chronic pain can eventually result in changes within the central nervous system, sensitizing patients to noxious stimuli, reducing their pain threshold, and, ultimately, leading to poor responses to treatment.