At the Department of Neurosurgery in Trondheim, 17 patients with low backpain and sciatica have been operated upon using percutaneous lumbal discectomy. The procedure was carried out under local anaesthesia and all patients were discharged on the first day after operation. Seven patients recovered completely, four patients showed some improvement, and six patients showed no change. All the patients who reported a complete recovery experienced pre-operative stress-dependent radicular pain with mild neurological deficits. In contrast, the group of patients who showed no change suffered more constant pain, with a diffuse localization and no neurological deficits. It is important to make a thorough pre-operative evaluation of these patients, and correct selection is essential to achieve a good result.