Selection of the lowest level for fusion in adolescent idiopathic scoliosis - A systematic review and meta-analysis

Study design A systematic review of studies reporting pain as a long-term outcome after spinal fusion surgery for treatment of adolescent idiopathic scoliosis. Objective To identify studies that report pain after spinal fusion surgery for scoliosis based on the distal extent of fusion and to combine results to determine if there is an increased incidence of back pain in patients treated with fusion to the lower lumbar spine. Summary of Background Data The methods and results of existing studies are inconsistent and only occasionally reach statistical significance. No thorough review of the available information has been published. Methods An electronic literature search was performed to identify studies that met predetermined eligibility criteria. Data extracted included number of cases fused to L3 or above, to L4 or L5, and the number of those cases experiencing pain. Further, when possible, the pain variable was stratified into severe or mild categories to allow a more specific subanalysis. Results Eight studies met inclusion criteria. The meta-analysis for occurrence of pain, the primary outcome, resulted in a final odds ratio of 1.29 (95% CI 0.91-1.82, n = 1,155). When pain was stratified according to severity and only those cases in the severe category considered for meta-analysis, the resulting odds ratio was 1.43 (95% CI 0.72-2.82, n = 900). Neither analysis reached statistical significance. Conclusions Although there was a trend toward increased pain in patients whose fusion extended to L4 or L5, there was no statistically significant association between the distal level of fusion and incidence of subsequent back pain, both with and without stratification according to severity of back pain. Because of the limitations of published research, the effect of fusion into the lower lumbar spine on back pain is unknown. Higher quality studies with long-term follow-up and consistent reporting of outcomes are needed.