Sagittal spinopelvic alignment after spinal fusion in degenerative lumbar scoliosis: a meta-analysis

Objective: This meta-analysis aimed to investigate the changes in sagittal spinopelvic alignment in degenerative lumbar scoliosis (DLS) from the preoperative state to the last follow-up.Methods: The MEDLINE via PubMed, Cochrane, Scopus, and Embase databases were searched for studies published between January 2010 and January 2019 evaluating radiological parameters including the coronal Cobb angle, sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) in DLS. Two authors performed data extraction independently. All discrepancies were resolved by consensus.Results: The 34 studies identified showed significant decreases in overall and subgroup Cobb angles from the preoperative state to the last follow-up. Both overall TK and LL were significantly increased from the preoperative state to the last follow-up. In subgroup analysis, LLs in the long fusion, combined approach, and posterior approach group were significantly increased at the final follow-up, but the LL increase in the short fusion group was not significant at the last follow-up. However, there was no significant change in SVA, PI, SS, and PT from the preoperative state to the last follow-up.Conclusions: A literature review identified 34 studies reporting preoperative and last follow-up data on spinal fusion in DLS. Despite heterogeneity, a limited meta-analysis showed significant improvement in the coronal Cobb angle, TK, and LL after spinal fusion in DLS. A large, randomized clinical trial would be necessary to validate our results.