7. Spondylolysis and spondylolisthesis Spondylolysis is the defect in the pars interarticularis which is the piece of bone that attaches the superior to the inferior facet. So when that is not connected, the restrain to slippage is gone. The facet joints are no longer connected to the spine. Actually 3% of the population has spondylolisthesis or spondylolysis. So it is common and obviously most people do not have to have surgery. We treat it just like the other things. A percentage of the time in people who have spondylolisthesis the symptoms are coming from the level above and not from the spondylolisthesis. So you might even have them do press-up exercises, if that seems to work. You are treating the upper area. If they do have trouble, it is from lateral canal stenosis because at the area of the crack of the bone there is constant motion and either build up a fibrous tissue plus the vertebra slip which distorts the size of the nerve hole resulting in nerve entrapment. And so for radiculopathies with spondylolishtesis, you treat it just like the other things, you try to block the patient right away and if you can control it, you set them up for stabilization training and try to hold the vertebra as straight as possible. When it is operated on, it usually has to be fused however not always. Sometimes you can just decompress them. So those are the three most common surgical issues; herniated disc, spinal stenosis and spondylolisthesis with or without radiculopathy.