RESUMO
STUDY DESIGN: A retrospective study. OBJECTIVES: To analyse associated preoperative conditions and postoperative causes of sagittal imbalance and to analyze clinical results of surgical treatment of lumbar degenerative kyphosis. SUMMARY OF LITERATURE REVIEW: There have been many controversies and high possibility of unsatisfactory results in surgical treatment of symptomatic degenerative lumbar kyphosis, which was complicated condition usually needed multi-level operation in old age. MATERIALS AND METHODS: We analyzed 24 patients who complained of long standing stooping as one of main symptoms with radiologically measured lumbar kyphosis and underwent surgical restoration of lumbar lordodsis with long segmental spinal fusion from 1995 to 1999. Mean follow-up was 31.9months(from 24 to 48 months). Operative treatments were posterolateral fusion with pedicular screw(15 cases), anterior and posterior interbody fusion(5 cases), posterior interbody fusion with cage(1 case) and decancellation osteotomy(3 cases). Cases divided into 2 groups(Group A: improved stooping, Group B: recurred stooping) were evaluated by radiological measurement of changes in surgically restored lumbar lordosis correlated with clinical improvement of stooping. Overall clinical results were evaluated according to Kirkaldy-Willis criteria. RESULTS: The associated conditions of preoperative lumbar kyphosis were recognized as multiple disc degeneration, segmental instability, degenerative vertebral wedging and pseudospondylolisthesis. Post-operative stooping recurred in 5 cases and caused by adjacent kyphosis in 2 cases, loss of correction in 1 case and both in 2 cases. Loss of correction was associated with pseudarthrosis in 1 case, screw loosening in 3 cases and allograft collapse in 2 cases. According to Kirkaldy-Willis, 8 cases of unsatisfactory clinical results consisted of 3 cases of pseudarthrosis out of 19 cases of Gruop A and all cases(5 cases) in group B. Most of correction loss occurred at lower lumbar spine(L3-S1) and was closely related to post-operative sagittal imbalance. CONCLUSIONS: Maintenance of well corrected lumbar lordosis for sagittal balance and prevention of pseudarthrosis were mandatory for good clinical outcome in surgical treatment of lumbar degenerative kyphosis.