Postoperative complications of S2AI versus iliac screw in spinopelvic fixation: a meta-analysis and recent trends review

Iliac screw constructs have been a major advancement in spinopelvic fixation demonstrating superior biomechanics as compared with earlier pelvic spanning constructs. However, drawbacks such as screw site prominence and wound complication have led to the development of a lower profile S2AI iliac screw. In this study, we aimed to study the differences in complication rates between the traditional iliac and S2AI fixations via a pooled analysis of the available head-to-head comparisons between S2AI and iliac screws. We also aimed to study the iliac screw complications trend over the years particularly with reference to recent modifications in its screw insertion techniques. A meta-analysis with attention to the comparison of patients who underwent iliac screws and S2AI screws was conducted. The following databases were utilized: PubMed, Scopus, Web of Science, Embase, and Cochrane Central Register of Controlled Trials database. Using the search terms: iliac, iliac bolts, S2AI, sacral 2 alar iliac, sacral two alar iliac, reviewers independently selected eligible studies, analyzed data and evaluated the risk of bias. Data analysis was conducted using RevMan 5.3 software. A total of 215 articles were identified, with 6 clinical studies directly comparing outcomes of S2AI pelvic fixation versus iliac screw fixation. A total of 477 patients were included, of which 255 patients (53.5%) underwent S2AI screw and 222 (46.5%) underwent iliac screw fixation. Our pooled analysis favored S2AI screws with regards to postoperative complications of screw prominence (odds ratio [OR]=5.99, 95% confidence interval [CI]=2.168–16.523, p