Isthmic spondylolisthesis in a nonambulatory patient: a case report.

Study Design: Case report.

Objective: We present a case of a nonambulatory patient with an isthmic spondylolisthesis.

Summary Of Background Data: Pars defects are thought to be due to repeated mechanical stress on the spine in individuals with bipedal posture. Epidemiologic and mechanical studies have supported the idea that repeated lumbar flexion and extension can lead to stress fractures of the pars interarticularis and subsequent spondylolisthesis. There are no documented cases of isolated pars defects in nonambulatory patients. We present a case report of an isolated isthmic spondylolisthesis in a patient who has never ambulated.

Methods: Discussion of the patient's clinical and radiologic history with a brief review of the relevant background literature.

Results: A pars interarticularis lesion was identified on plain radiographs in a 17-year-old girl with mixed spastic-athetoid cerebral palsy who never ambulated.

Conclusion: Although ambulatory individuals who engage in activities with repeated lumbar flexion have an increased risk of isthmic spondylolisthesis, this condition can occur in those who do not walk as well. This case illustrated that, although repetitive stress on an upright spine can increase an individual's propensity to develop a pars interarticularis defect, bipedal posture is not an absolute requirement for the development of this lesion.