Spinal stenosis is usually a slow process that occurs over years and results in thickening of the ligaments, formation of bone spurs, and deterioration of the disc material. As a result, the spinal canal narrows and pinches the nerves. Bone spurs may also press on the spinal cord.

The narrowing of the spinal canal usually develops over time as part of the aging process. While spinal stenosis typically occurs in people age 50 or older, it can also develop sooner due to injury or from birth (congenital factors).