We have reviewed our experience with spinal cord stimulation in treating patients with the failed back surgery syndrome and have assessed patient and patient-selection characteristics as predictors of the long-term outcome. Neuroradiological investigations eliminated the possibility of a surgically treatable lesion and electromyogram assessed the chronic radicular suffering in correlation with the complaints and the clinical examination of the patient. Excellent pain relief (75% or more) during 1 week of trial stimulation and no major psychiatric or psychological pathology were criteria of selection. Seventy-eight patients underwent trial stimulation. Fourteen (18%) failed to obtain excellent pain relief during 1 week of stimulation and their electrodes were removed. The remaining 64 underwent an internalization of the system and they were followed by a clinical observation every 3 months and this for a mean follow-up period of 4 years (range: 1-7 years). Thirty-five patients (55%) continued to experience at least 50% of pain relief at the latest follow-up. Fifty-eight patients (90%) were able to reduce their medication, 39 patients (61%) reported a change in lifestyle, in that their ability to perform daily activities had improved significantly. Fifty-three patients (83%) continued to use their device at the latest follow-up.