Spondylolysis and Spondylolisthesis

Spondylolysis and spondylolisthesis are related but not the same.

• Spondylolisthesis is when one vertebra slips out of place over the vertebra below.
• Spondylolysis is a common cause of spondylolisthesis, because the crack in the vertebra may cause the bone to slip.If you have spondylolysis, you typically have a weakness in a section of the vertebra called the pars interarticularis. This thin piece of bone connects the facet joints, which link the vertebrae directly above and below to form a working unit that permits movement of the spine. The cracks are often called pars fractures.

While we don’t know exactly why the weakness occurs, your genes might play a role. You may be born with thin vertebrae, which puts you at higher risk for pars fractures. Repetitive trauma to the lower back — for example, injuring yourself over and over through sports or other activities — can also weaken the pars interarticularis.

Healthcare providers typically use nonsurgical methods to treat spondylolysis. Your care might include activity modification medications and physical therapy. In rare cases, surgery is necessary.