Spondylolisthesis and related disorders. A correlative study of 105 patients.

A close relation exists among the alterations in the lumbosacral spine designated as spondylolysis, isthmic spondylolisthesis, degenerative spondylolisthesis, and prespondylolisthesis. While the former two conditions are probably caused by faulty development and subsequent minor traumata or repeated stresses, the third condition is caused by degenerative changes associated with anatomic variations; the fourth condition is a static insufficiency leading to faulty alignment. In 105 patients, the initial preferred management of these conditions was conservative. Thirty-four patients who developed persistent symptoms of spinal instability and/or intractable neurologic deficits were treated surgically. The results were generally successful.