The cause of lumbar radicular symptoms often remains elusive after standard clinical and radiographic evaluation. Selective nerve root block is a useful test to indicate whether the pain is neural in origin and/or whether nerve root is pain producing in these patients with equivocal clinical and imaging studies. Over 8 years, the author performed selective nerve root blocks in 215 patients. Of this group, 78 patients underwent surgery. Following surgery, 71 patients were available for a minimum 12-month follow-up. The preoperative diagnoses included previously unoperated-upon lumbar disc herniation, previously unoperated-upon spinal canal stenosis, and prior lumbar surgery. The average follow-up was 34 months (range, 12-96 months). Overall, there were 38 good (53%), 16 fair (23%), and 17 poor (24%) surgical results. The results for those patients who had had prior surgery were disappointing (52% poor). These data reaffirm that surgical intervention should only be recommended for previously operated-upon patients with unequivocal findings.