Anatomical Factors Predictive of Difficult Biliary Cannulation During ERCP

Abstract

Background: Limited data are available in the literature in regard to the anatomical factors that might be related to difficult biliary cannulation during ERCP. Aim: The aim of this study was to elucidate the anatomical factors predictive of difficult biliary cannulation during ERCP. Patients and Methods: Three hundred seventy-two consecutive patients(212 men, 160 women; mean age, 64.7 years; age range, 16-96 years) who underwent ERCP at the Yokohama city university hospital from April 2005 to October 2006 for various biliary or pancreatic disorders were enrolled in this study. Difficult biliary cannulation was defined as failure biliary cannulation after a 20-minute attempt. The characteristics of the group needing precut papillotomy using a needle knife (NKPP) (n = 40, 12%) were compared with those of a group in which only standard maneuvers were performed (n = 332, 88%). Various factors (patient age, gender, presence of periampullary diverticulum, length of the narrow distal segment, diameter of the common bile duct, cholangiographic angulation of the common bile duct, location of the cystic duct, presence of benign biliary stricture, presence of malignant biliary stricture, and the presence of choledochlithiasis were retrospectively analyzed in the two groups to identify any relationship of these factors to difficult biliary cannulation in patients undergoing ERCP. Results:The success rate of biliary cannulation facilitated by NKPP in patients with difficult biliary cannulation was 92% (37/40), yielding a total success rate of 99% (364/372). Univariate analysis revealed that a long narrow distal segment, sharp cholangiographic angulation of the common bile duct, presence of malignant biliary stricture, and a lower location of the cystic duct were significantly associated with difficult biliary cannulation during ERCP (p < 0.05). Multivariate logistic regression analysis showed that sharp cholangiographic angulation of the common bile duct(OR = 1.021, 95% CI 1.002-1.041, p = 0.0333), presence of malignant biliary stricture (OR = 2.896, 95% CI 1.236-6.786, p = 0.0144)and a lower location of the cystic duct(OR = 5.263, 95% CI 1.556-17.805, p = 0.0076) were independent risk factors associated with difficult biliary cannulation. Conclusions: In conclusion, a long narrow distal segment, sharp cholangiographic angulation of the common bile duct, presence of malignant biliary stricture, and a lower location of the cystic duct are risk factors for difficult biliary cannulation during ERCP. However, NKPP is a useful and promising method for deep biliary cannulation in such difficult cases.