How does neuropathophysiology affect the signs and symptoms of spinal disease?

A complex relationship exists between back pain and the presence of spinal disease. Particularly in chronic situations, back pain and its behavioural and emotional consequences are as likely to reflect the influence of psychosocial factors as any underlying spinal pathology. Nevertheless, physical factors are clearly important and it is significant that whereas in normal discs only the outer third of the annulus fibrosus is innervated, a much more extensive innervation develops in the presence of degeneration. Inflammation, as evidenced by leukocyte infiltration and expression of inflammatory mediators, is associated with disc degeneration and serves to alter the neural responses resulting in local and referred pain. It is probable that similar inflammatory processes, as well as direct root compression, contribute to radicular symptoms following disc herniation. An appreciation of these mechanisms encourages the search for novel treatments and permits a more rational and effective use of existing strategies for relieving pain.