Lumen-Apposing Metal Stents for Endoscopic Drainage of Intra-abdominal Abscesses: A Systematic Review

Intra-abdominal abscesses require timely source control, most commonly achieved through image-guided percutaneous drainage. However, percutaneous access may be unfeasible or ineffective in selected cases due to anatomical constraints, interposed organs, or prior drainage failure. Endoscopic ultrasound (EUS)-guided drainage using lumen-apposing metal stents (LAMS) has emerged as an alternative minimally invasive strategy, although evidence supporting its use in non-pancreatic intra-abdominal abscesses remains limited and heterogeneous. This systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of PubMed/MEDLINE was performed from database inception through January 2024 to evaluate the feasibility, effectiveness, and safety of EUS-guided LAMS for non-pancreatic intra-abdominal abscesses. The primary objective was to translate these findings into a conservative, anatomy-driven approach to support clinical decision-making. A total of 16 studies involving 99 patients were identified, including observational studies, case series, and case reports; studies focusing exclusively on pancreatic fluid collections were excluded. Methodological quality and risk of bias were assessed using the Joanna Briggs Institute (JBI) checklists. Primary outcomes included technical and clinical success, while secondary outcomes comprised adverse events and reintervention rates. Sixteen studies met the inclusion criteria, consisting predominantly of retrospective series and case reports. Reported technical success ranged from approximately 92.5% to 100%, with clinical success rates between 88% and 100%. Adverse events were infrequent and generally mild, occurring in fewer than 10% of cases; these were predominantly mild, including transient abdominal or rectal discomfort, minor bleeding, and occasional stent migration. Most abscesses were pelvic or postoperative collections, commonly managed via transrectal or transcolonic access routes. Evidence supporting transgastric or transduodenal drainage was limited to carefully selected upper abdominal collections. EUS-guided drainage using LAMS appears to be a feasible and effective option in carefully selected patients with non-pancreatic intra-abdominal abscesses, particularly when percutaneous drainage is unfeasible or has failed. Success depends on strict apposition to the gastrointestinal lumen and adherence to the 'shortest-safe-path' principle, making it a viable rescue strategy after conventional drainage failure. Given the limitations of the available evidence, including small sample sizes and predominantly observational designs, this technique should be applied cautiously, with rigorous patient selection, strict anatomical considerations, and a predefined strategy for stent management and removal.