Seventy-nine percent of 312 patients who underwent lumbar disc surgery were evaluated at least 10 years postoperatively (mean equal to 13.7 years). Residual back and nerve root symptoms and functional impairment were equally as common among the 143 patients who underwent fusion as they were among the 64 patients who did not. Thirty percent of the patients whose spines were fused and 37.7% of those patients whose spines were not fused were considered long-term failures because of persistent symptoms or the need for reoperation. Thirty-seven percent of the fusion patients had persistent graft donor site symptoms. Examined patients showed a high percentage of residual neurologic defects. An unexplained positive Trendelenburg sign was present in 14.8% of the fusion patients and in 18.2% of the patients whose spines were not fused. Although retrospective studies often have problems of accuracy, this analysis confirms other observations that midline spinal fusion offers few benefits in the management of lumbar disc disease.