Current Evidence on Endoscopic Biliary Drainage in the Era of Surgically Altered Anatomy: A Narrative Review

: Endoscopic retrograde cholangiopancreatography (ERCP) remains the reference standard for biliary drainage, yet it fails in up to 15% of cases, most notably when a surgically altered anatomy (SAA) is present. The expanding use of bariatric and oncologic gastrointestinal surgery has increased the number of patients in whom the papilla is displaced, unreachable, or replaced by a biliodigestive anastomosis, making conventional access difficult or impossible. This narrative review appraises the current evidence on endoscopic biliary drainage in SAA, focusing on procedural efficacy, anatomical peculiarities, adverse-event profiles and technical considerations to guide clinical decision-making. Available strategies include luminal techniques, duodenoscope-assisted ERCP, forward-viewing (cap-assisted colonoscope) ERCP, and enteroscope-assisted ERCP, as well as endoscopic ultrasound-guided biliary drainage (EUS-BD), encompassing EUS-guided hepaticogastrostomy, EUS-guided antegrade stenting, EUS-guided rendezvous and EUS-directed transgastric/transenteric ERCP (EDGE/EDEE), and laparoscopic-assisted ERCP (LA-ERCP). No single approach is universally superior and available comparative data is mainly retrospective and affected by major selection bias. Technique selection should be tailored to the reconstruction type, indication (benign vs. malignant), limb length, expected survival, and local expertise, ideally within a multidisciplinary, high-volume setting. Adequately powered randomized trials incorporating quality-of-life and cost-effectiveness endpoints are still needed to define the optimal first-line strategy. This literature review encompasses the multiple strategies to achieve biliary drainage in surgically altered anatomy, highlighting strengths and weaknesses of each technique, as well as the preferred approach for each type of anatomical reconstruction.