Unilateral spondylolysis associated with spina bifida occulta and nerve root compression.

Three patients with unilateral spondylolysis and spina bifida occulta were treated with hemilaminectomy, pseudarthrosis excision, and bilateral posterolateral fusion. All patients had persistent radiating leg pain, a positive sciatic tension sign, an objective neurologic deficit, and neuroradiographic studies that confirmed isolated L5 nerve root entrapment at the pars defect. Postoperatively, all patients noted complete relief of their radicular symptoms.