Association between type of major duodenal papilla and difficult biliary cannulation at first endoscopic retrograde cholangiopancreatography in adults: a cross-sectional study with bootstrap method.

Background: The type of major duodenal papilla could be associated with difficult biliary cannulation at first endoscopic retrograde cholangiopancreatography (ERCP) in adults.

Methods: This retrospective cross-sectional study included patients undergoing ERCP for the first time by an expert endoscopist. We defined the type of papilla according to the endoscopic classification of Haraldsson in type 1-4.