Spondylolysis and Spondylolisthesis

View a step-by-step animation of spondylolisthesis

Spondylolysis is a spinal stress fracture of a bone structure called the pars intraarticularis. The fracture usually occurs not as a single traumatic event, but as the result of cumulative microtrauma from repetitive activity. Spondylolysis usually occurs in childhood and may not become symptomatic until many years later.

Over time, as the result of a pars intraarticularis defect, the adjacent vertebrae may slip forward, resulting in a condition known as spondylolisthesis. Another form, called degenerative spondylolisthesis, is caused by the degenerative deterioration of the facet joints and discs. Symptoms of both may include localized low back pain and/or radiating leg pain in the case of spondylolisthesis with nerve compression.