Spondylolysis and Spondylolisthesis

Spondylolysis and spondylolisthesis are separate, yet related conditions. Spondylolysis usually comes first, though not always. The term comes from Greek “spondylo,” which means “spine,” and “lysis”, The word “lysis” meaning ‘to divide’.

The cause of spondylolysis is not as clearly defined. Most specialists believe it is due to a genetic weakness of the pars interarticularis.

Spondylolysis is a stress fracture of the narrow bridge between the upper and lower pars interarticularis. It can occur on one side (unilateral) or both sides (bilateral) and at any level of the spine, but most often at the lower lumbar levels L4-L5 or L5-S1. If spondylolysis is present, then there is the potential to develop spondylolisthesis. Both spondylolysis and spondylolisthesis can be present at birth or occur through injury. The most common cause in adults is degenerative arthritis.

Spondylolisthesis is most often caused by spondylolysis. Another type of spondylolisthesis is degenerative spondylolisthesis, occurring usually after age 50. This may create a spinal stenosis (narrowing of the spinal canal).

Spondylolisthesis occurs when one vertebra slips forward in relation to an adjacent vertebra, usually in the lowest lumbar vertebral segment (L5). As a result, the L5 vertebral body slips forward on the S1 (sacral 1) vertebral body. This process is almost never due to trauma.

The symptoms that accompany a spondylolisthesis include pain in the low back or legs, muscle spasms, and weakness. Often, the symptom of spondylolisthesis is tightness of the hamstring muscles in the legs. Some people are symptom free and never even know they have the problem, until they find the disorder exists when revealed on an x-ray.

If the spondylolisthesis is non-progressive, no treatment except observation is required.

Conservative treatment includes 2 or 3 days of rest followed by trunk and abdominal strengthening exercises. A spine-care specialist may prescribe the wearing of a back brace for a short period of time while you strengthen the abdominal and lower back muscles. The brace may decrease muscle spasm and pain as well as help immobilize the spine and aid the healing process.

If required, the conservative treatment for spondylolysis and spondylolisthesis may include:

If patients do not respond to conservative treatment and slippage continues, surgery may be necessary. Surgery for spondylolisthesis needs to address both the instability of the spine and the compression of the nerve roots.