Cannulation time is a more accurate measure of cannulation difficulty in endoscopic retrograde cholangiopancreatography than the number of attempts

BACKGROUND Cannulation of the common bile duct (CBD) is the initial and sometime challenging step in endoscopic retrograde cholangiopancreatography (ERCP) procedure. Endoscopists often use cannulation attempts and cannulation time to grade cannulation difficulty, but a standard system has yet to be established. The objective of this study was to compare cannulation times with numbers of cannulation attempts, as measures of cannulation difficulty. METHODS We conducted a prospective study in a tertiary referral center, enrolling 58 patients who were undergoing ERCP for a variety of indications. Cannulation time and the number of cannulation attempts were recorded for each patient. A subset of 14 ERCPs had two observers assessing attempts at cannulation. Cannulation time, number of attempts and inter-observer variability in assessment of attempts were compared and studied. RESULTS The degree of agreement between two the methods (cannulation times and number of cannulation attempts) was unacceptable. There were considerable discrepancies between attempt tallies from two observers but the mean difference was statistically insignificant. CONCLUSION The grade of cannulation difficulty for a given ERCP procedure may differ when different methods are used (total cannulation time vs number of attempts); thus, grading by different methods should not be used interchangeably. Cannulation time is a more objective and more accurate assessment tool for grading cannulation difficulty than the number of attempts to cannulate the papilla.