This study comprises 78 patients who were treated for chronic back pain at a multidisciplinary, multimodal pain treatment center. These patients were selected from 494 patients examined by the authors because all of their previous medical records, operative notes, and imaging studies were available for review. The records and imaging studies were reviewed independently by a neurosurgeon and an orthopedist, and a retrospective decision was made concerning the historical and physical findings correlated with imaging studies in order to provide justification for the intervention. At the time of admission to the pain treatment center, 16 patients had no physical abnormalities that would explain their back complaint and 16 patients exhibited minor postoperative changes insufficient to cause disabling pain. Twenty-seven patients suffered from a complication of previous surgery, 13 had spondylotic disease, and in six a new diagnosis was established. Comprehensive psychiatric evaluation of the 78 patients revealed that 10 patients had a definitive psychiatric diagnosis, 34 were diagnosed as having a maladaptive personality disorder, and 34 had a normal pre-pain personality. Sixty-seven patients suffered from reactive depression. Fifty-four patients were taking medications at doses higher than usually prescribed, 58 misused narcotics, nine had drug addiction, and 54 were suffering withdrawal symptoms. Of the 78 patients, 64 underwent a total of 171 operations, an average of 2.6 per patient. The authors applied the clinical criteria approved by the American Association of Neurological Surgeons and the American Academy of Orthopedic Surgeons for selection of surgery or chemonucleolysis in the treatment of the herniated disc to these patients. Preoperative imaging studies were normal or demonstrated nonspecific degenerative disc disease in 52 patients. Twenty-six patients had a diagnosis based on radiological findings that warranted surgery. Clinical criteria justifying intervention were met in 25 patients and not met in 53. Imaging and clinical criteria for a second operation were met in 18 (40%) of the patients. After the second operation all patients met the criteria: subsequent surgery was necessary to treat effects of an earlier operation in 73%. These data indicate that many of these patients with failed-back syndrome underwent an original operation based on a persistent complaint of pain, frequently coupled with an underlying psychiatric abnormality, although they did not meet the criteria generally accepted by neurosurgeons for intervention at the time of first surgery.