Single anastomosis sleeve ileal (SASI) bypass outcomes and complications: single-arm meta-analysis

Background: Single Anastomosis Sleeve Ileal (SASI) bypass combines sleeve gastrectomy with a single anastomosis to the ileum, preserving digestive continuity to reduce deficiencies while treating obesity-related conditions. Methods: This study systematically reviewed SASI bypass outcomes and conducted a single-arm meta-analysis to assess its efficacy and safety. A comprehensive literature search across PubMed, Scopus, Embase, and Cochrane databases initially identified 387 articles, with 38 studies meeting inclusion criteria, contributing data on a maximum of 2,555 patients. Follow-up ranged from 6 to 60 months. Results: Meta-analysis showed significant weight loss, with pooled Excess Weight Loss Percentage (EWL%) of 63.07% at 6 months, 82.44% at 12 months, and 93.21% at 24 months. The procedure demonstrated high remission rates for obesity-related conditions, including diabetes (92.67%), hypertension (79.06%), dyslipidemia (82.64%), gastroesophageal reflux disease (GERD) (81.63%), and obstructive sleep apnea (OSA) (81.04%). Postoperative complications were classified using the Clavien-Dindo grading system, with an overall mean complication rate of 13.70%. Mild complications (Grades I-II) accounted for 7.74%, while severe complications (Grades III–IV) had a mean rate of 5.18%. No deaths were reported. Conclusions: These findings suggest SASI bypass is a highly effective metabolic and bariatric procedure, achieving substantial weight loss and high remission rates for multiple obesity-related conditions. Given its efficacy, SASI may benefit patients with higher body mass index (BMI) and multiple obesity-associated medical conditions. While most complications are mild and severe ones infrequent, further comparative studies are needed to establish its advantages over other bariatric techniques. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.