Development of a Scoring System for Predicting the Difficulty of Bile Duct Cannulation and Selecting the Appropriate Cannulation Method

Selective biliary cannulation in endoscopic retrograde cholangiopancreatography can be challenging due to factors like papillary morphology. Various patterns indicate cannulation difficulty, but the combinations causing difficulty and the optimal cannulation method for each scenario are unclear. This study aimed to identify cannulation difficulty patterns and develop a predictive scoring system for selecting the appropriate cannulation method. We retrospectively compared 776 patients with naïve papilla, dividing them into conventional contrast cannulation (N = 510) and salvage technique (N = 266) groups. The salvage group included patients using pancreatic duct guidewire placement and/or wire-guided cannulation due to difficulties with the contrast method. Papillary morphology (Haraldsson's classification), periampullary diverticulum (PAD), and scope operability were analyzed using multiple regression to identify risk factors for cannulation difficulties. Factors were scored based on hazard ratios to access combinations causing difficulties. The salvage group had more older patients and higher frequencies of type 2 (small), type 3 (protruding or pendulous), type 4 (creased or ridged) papillae, PAD, and poor scope operability. Significant risk factors in the multivariate analysis included type 2 [odds ratio (OR) 6.88], type 3 (OR 7.74), type 4 (OR 4.06) papillae, PAD (OR 2.26), and poor scope operability (OR 4.03). Pattern recognition scores were significantly higher in the salvage group (1.31 vs. 3.43, P