In a prospective single-blind study, 60 patients surgically treated for lumbar disc herniation underwent clinical examination and computed tomography preoperatively and 3 months after surgery. At follow-up (58 patients; median, 31 months; range, 21-37 months), 29 patients had an excellent outcome (51%), 20 improved (33%), and 9 were unchanged or worse (16%). Dural or radicular scar tissue was present by computed tomography in 88% of the patients, but the findings could not be correlated with the clinical outcome. Recurrent or persistent disc herniation was found in 9% of the patients. The clinical outcome of patients with abnormal computed tomography did not differ significantly from patients without this finding. A relation between facet joint degeneration and less successful clinical outcome was demonstrated. Computed tomography (without contrast) 3 months after surgery gave little information which could be correlated with the clinical outcome. Patients with an excellent outcome had all degrees of intraspinal scar tissue.