{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T13:23:37Z","timestamp":1781616217431,"version":"3.54.5"},"reference-count":22,"publisher":"Asian Spine Journal (ASJ)","issue":"2","license":[{"start":{"date-parts":[[2019,11,5]],"date-time":"2019-11-05T00:00:00Z","timestamp":1572912000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["asianspinejournal.org"],"crossmark-restriction":true},"short-container-title":["Asian Spine J"],"published-print":{"date-parts":[[2020,4,30]]},"abstract":"<jats:p>Study Design: A retrospective cohort study.Purpose: The purpose of this study was to investigate the prevalence and risk factors for S2 alar-iliac (SAI) screw loosening following lumbosacral fixation, with a minimum 2-year follow-up.Overview of Literature: Although SAI screws allow surgeons to perform lumbosacral fixation with a low profile and enhanced biomechanical strength, screw loosening following surgery can occur in some cases. However, few studies have investigated the prevalence and risk factors for SAI screw loosening.Methods: This retrospective study included 35 patients (mean age, 72.8\u00b18.0 years; male, 10; female, 25) who underwent lumbosacral fixation using SAI screws with at least 2 years of follow-up. SAI screw loosening and L5\u2013S bony fusion were assessed using computed tomography. The period for which the screws appeared loose and the risk factors for SAI screw loosening were investigated 2 years after surgery.Results: A total of 70 SAI screws and 70 S1 pedicle screws were inserted. Loosening was observed 0.5, 1, and 2 years after surgery in 17 (24.3%), 35 (50.0%), and 35 (50.0%) SAI screws, respectively. Bony fusion rate at L5\u2013S was significantly lower in patients with SAI screw loosening than in those without screw loosening (65.0% vs. 93.3%, p =0.048). The score for SAI screw contact with the iliac cortical bone and the bony fusion rate at L5\u2013S were significantly lower in the loosening group than in the non-loosening group (1.8\u00b10.5 vs. 2.2\u00b10.3, p &lt;0.001, respectively). Postoperative pelvic incidence\u2013lumbar lordosis was significantly higher in the loosening group than in the non-loosening group (7.9\u00b0\u00b115.4\u00b0 vs. 0.5\u00b0\u00b18.7\u00b0, p =0.02, respectively).Conclusions: SAI screw loosening is closely correlated with pseudoarthrosis at L5\u2013S. Appropriate screw insertion and optimal lumbar lordosis restoration are important to prevent postoperative complications related to SAI screws.<\/jats:p>","DOI":"10.31616\/asj.2019.0127","type":"journal-article","created":{"date-parts":[[2019,11,4]],"date-time":"2019-11-04T07:52:38Z","timestamp":1572853958000},"page":"177-184","update-policy":"https:\/\/doi.org\/10.31616\/crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["The Prevalence and Risk Factors for S2 Alar-Iliac Screw Loosening with a Minimum 2-Year 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