Spondylolithesis refers to incorrect stacking of the spinal vertebra on top of each other.  It may also refer to mild or moderate instability of the spine. This incorrect stacking creates a “step off” of the vertebra seen on X-Ray. Normally, the bones stack up nicely on top of each other. Most likely due a genetic weakness of the ligaments supporting the spine (or trauma), one vertebra of the back-slides off of another. This may result in bony degeneration/arthritis, and/or impact on the nerve roots as they leave the spine, producing sciatica.

Spondlylolithesis 1     Spondlylolithesis 2

The pain with spondylolithesis is usually dull and constant, and is worse with spinal flexion and twisting. Not only may sciatica-type pain ensue, but symptoms like those of spinal stenosis are sometimes seen. Conventional treatment includes monitoring and physical therapy. More severe cases may require surgery for stabilization.