STUDY DESIGN: This retrospective study was designed to investigate the effectiveness of surgical procedure for degenerative lumbar scoliosis. OBJECTIVES: To evaluate surgical outcome on symptomatic degenerative lumbar scoliosis and to analyze the cause of decompensation of the curve at the above segment adjacent to fused vertebra. SUMMARY OF LITERATURE REVIEW: Few studies evaluated the surgical outcome of patients with symptomatic degenerative lumbar scoliosis, and observed the postoperative deompensation of the curve at adjacent segment. MATERIALS AND METHODS: Thirty patients were retrospectively reviewed. All patients underwent decompressive laminectomy, transpedicular screw fixation, and intertransverse fusion by autogenous bone graft. Scoliotic angle within curves and within fused segments were measured by Cobb's method. Changes of the adjacent segment were analyzed. RESULTS: The overall satisfactory clinical results was noted in 25(83%) of 30 patients. The curve preoperative averaged 13.3 degrees +/- 4.0 degrees, 5.5 degrees +/-3.2 degrees after surgery and curves at final follow-up 8.6 degrees +/-6.2 degrees. In six patients(20%) decompensation of the curve with more than 5degrees occurred at the adjacent segment above to the fused segments. This decompensation of the curve closely correlated to the lateral translation at adjacent segments and postoperative pain. Sagittal profile was not significantly improved following surgery. CONCLUSIONS: Uncorrected lateral translation at the unfused adjacent segment resulted in progression of the coronal deformity at upper adjacent segment to fused vertebrae. Therefore, in fusion operation upper end vertebra with lateral instability should be included to prevent the postoperative decompensation.