Impact of supine versus prone position on endoscopic retrograde cholangiopancreatography performance: a retrospective study

Background Endoscopic retrograde cholangiopancreatography (ERCP) is frequently performed in the prone or supine position. We compared the technical success and other outcomes between these positions. Methods This was a retrospective cohort study using the Clinical Outcomes Research Initiative database. Demographics, procedure and fluoroscopy time, visualization of main structures, and technical success rates were compared between the supine and prone positions. Univariate and multivariate regressions were performed to adjust for age, sex, ethnicity and clinical setting. Results A total of 21,090 patients who underwent ERCP were included, of whom 1769 (8.4%) were supine and 19,321 (91.6%) were prone. The common bile duct (CBD) was visualized and cannulated in 89.1% of supine vs. 91.4% of prone positions (P=0.017), while the ampulla was visualized in 97.1% of supine vs. 97.7% of prone (P=0.414). The ERCP was incomplete in 10% of supine vs. 5% of prone cases (P<0.001). On multivariate analysis, supine position required shorter procedure times than prone (adjusted odds ratio [aOR] 0.98, 95% confidence interval [CI] 0.980.98; P<0.001). The supine position also yielded lower odds of CBD visualization and cannulation (aOR 0.63, 95%CI 0.44-0.91; P=0.011) and higher odds of an incomplete examination (aOR 1.84, 95%CI 1.46-2.30; P<0.001) vs. prone. Conclusions The supine position leads to shorter procedures but is more likely to result in poorer visualization and cannulation of the CBD and an incomplete examination. This may reflect the technical difficulty of performing ERCP in the supine position for the endoscopist. Our study supports recommendations for an individualized ERCP approach.