The Science of Degenerative Disc Disease

Degenerative disc disease represents the natural aging process of your intervertebral discs, though it can occur prematurely due to various factors. Your discs are composed of an outer fibrous ring (annulus fibrosus) and an inner gel-like core (nucleus pulposus) that normally acts as a shock absorber between vertebrae. As discs age, they lose water content and the nucleus pulposus becomes less gel-like, reducing the disc's ability to distribute loads evenly. This dehydration process leads to decreased disc height and can result in small tears in the annulus fibrosus. When the disc loses height, it alters the biomechanics of the entire spinal segment. The facet joints, which normally share load with the discs, begin to bear a greater proportion of the forces passing through that level of the spine. This can lead to accelerated wear of these joints and may contribute to the development of bone spurs and other arthritic changes. Despite the name, degenerative disc disease isn't truly a disease but rather a description of the structural changes that occur over time. It's important to understand that these structural changes don't always predict pain levels - many people have significant disc degeneration visible on imaging scans but experience no symptoms whatsoever. Conversely, some individuals with minimal structural changes may have considerable pain. This disconnect between imaging findings and symptoms highlights why treatment focuses on function and symptoms rather than structural abnormalities.