In situ posterolateral fusion for spondylolisthesis.

In this series spondylolisthesis was treated operatively in children and adolescents who had a displacement greater than 50% even if they were asymptomatic. In youngsters with less than 50% displacement and in adults, operative stabilization was performed if the displacement was progressive or if there were persistent symptoms unresponsive to conservative treatment that interfered with the patient's normal activities. The operation consisted of a posterolateral fusion in situ. Usually a laminectomy was not performed unless there were signs of severe neural compression. No reduction of the spondylolisthesis was attempted. We reviewed 38 cases treated operatively with a mean follow-up of 7 years. Twenty patients were younger than 20 years at the time of operation and 10 of these had greater than 50% displacement. The results were good to excellent in 90% (18 patients). In the adult group (18 cases) the results were less favorable, but still good to excellent in 72% (13 patients). In the adult group pseudarthrosis frequently occurred at the L4-L5 level. There were no neurologic complications postoperatively. Fusion in situ for spondylolisthesis is a safe operation giving satisfactory results.