Deep Cannulation of the Common Bile Duct at Endoscopic Retrograde Cholangiopancreatography: How Challenging Is It?

Abstract

Background: A key step in endoscopic retrograde cholangiopancreatography (ERCP) is to cannulate the common bile duct (CBD) and/or pancreatic duct (PD). Despite the advances in endoscopic techniques, cannulation remains an invariably technical challenge at times. A review of the literature revealed that no studies have been carried out to document the degree of difficulty in cannulation. Aim: To provide data to document the degree of difficulty in cannulation at ERCP. Methods: A prospective study to precisely document the time spent on each step during ERCP, including position time (the time from esophageal intubation to the time of appropriate positioning in order to attempt the cannulation of the ampulla), PD cannulation time (the time from initiating cannulation to the time of obtaining a pancreatogram), initial common bile duct (ICBD) cannulation time (the time from initiating cannulation to the time of obtaining an initial cholangiogram) and deep common bile duct (DCBD) cannulation time (the time from initiating cannulation to the time of the positioning of a cannulator deep inside the CBD). Results: Fifty-eight consecutive successful ERCP procedures were enrolled in the study. PD and ICBD cannulation rates were 96% and 90% respectively. DCBD cannulation rate was 78% (45 cases). The average time to complete an ERCP procedure was 46.65 minutes. The average position time was 3.9 minutes. The average time taken to perform PD cannulation was 2.66 minutes (6% of the entire procedure time). The average times taken to perform initial and deep cannulation of the CBD were 12.2 and 30.2 minutes respectively. This constituted 26% and 65% of the entire procedure time respectively. The degree of difficulty of DCBD cannulation was defined by three categories: failure to cannulate (22% of the cases), significant difficulty to cannulate defined as longer than thirty minutes to achieve that end point (31% of the cases), and easy/relative easy to cannulate (47% of the cases). There was a statistically significant difference when comparing PD or ICBD cannulation times to that of the DCBD (p value<0.001). Conclusion: DCBD cannulation was the longest step in ERCP. DCBD cannulation is still a technical challenge in some cases even in experienced hands. Hence, Solutions resulting in a shortening of the DCBD cannulation time will significantly shorten the ERCP procedure time.