Endoscopic retrograde cholangiopancreatography (ERCP) is conventionally performed in the prone or left lateral position (PP/LLP), providing optimal anatomical alignment and easier biliary cannulation. However, the supine position (SP) may facilitate airway management and anaesthetic safety, particularly in patients with obesity, respiratory compromise, or recent abdominal surgery. This study aimed to compare the efficacy, safety, and procedural outcomes of ERCP according to patient positioning in a tertiary Moroccan centre.

A retrospective observational study was conducted at the Hepato-Gastroenterology Department, Mohammed VI University Hospital, Marrakech, from January 2021 to October 2025. A total of 738 consecutive ERCPs were analysed. Positions used: prone/lateral (PP/LLP, n = 671, 91%) and supine (SP, n = 67, 9%). Data collected included demographics, indication, cannulation success, procedure duration, and adverse events (cardiopulmonary events, post-ERCP pancreatitis [PEP], bleeding, perforation). Statistical analysis was performed using SPSS 26.0, with p < 0.05 considered significant.

Mean age was 58 ± 13 years, with 56% females. Main indications were choledocholithiasis (62%), malignant obstruction (24%), benign strictures (9%), and others (5%). Cannulation success was significantly higher in the prone/lateral group (93.1% vs 88.0%; p = 0.04). Mean procedure time was comparable (32 ± 10 min vs 34 ± 12 min; p = 0.27). Cardiopulmonary events occurred in 2.6% overall (PP/LLP = 2.4%, SP = 2.9%; p = 0.71). PEP occurred in 4.6% (PP/LLP = 4.5%, SP = 5.2%; p = 0.56). Bleeding occurred in 1.8% (1.7% vs 2.3%; p = 0.63), and perforation in 0.5% (0.4% vs 0.8%; p = 0.48). No procedure-related mortality was recorded.

Over this four-year experience, the prone/lateral position provided a higher ERCP success rate without prolonging procedure time or increasing complications. The supine position remains a safe and comfortable alternative for selected high-risk patients when prone positioning is not feasible. A patient-tailored strategy is recommended to optimise both technical performance and anaesthetic safety.