Impact of Papillary Morphology and Diverticular Type on Needle-Knife Papillotomy in Patients with Periampullary Diverticulum with Difficult Biliary Cannulation.

Background/Objectives: While previous studies have explored the relationship between periampullary diverticulum (PAD) and conventional endoscopic retrograde cholangiopancreatography (ERCP) success, data on advanced cannulation techniques like needle-knife papillotomy (NKP) remain limited. This study aimed to assess NKP outcomes in PAD patients with difficult biliary cannulation. Methods: A retrospective study was conducted on 122 PAD patients who underwent NKP in a single center. Patient characteristics, ERCP indications, common bile duct diameter, PAD type, diverticular size, major duodenal papilla (MDP) morphology, and post-ERCP adverse events were assessed. We also analyzed factors associated with the outcomes of NKP in patients with PAD. Results: Of the 122 patients, NKP was successful in 82 (67.2%) and failed in 40 (32.8%), with diverticular diameter being significantly larger in the failure group. By PAD type, the diverticular median diameters were 1.2 cm (type I), 0.9 cm (type II), and 0.5 cm (type III) (p < 0.001), with NKP success rates of 50%, 66.3%, and 75%, respectively (p = 0.391). By MDP morphology, the success rates were 73.7% (type I), 38.2% (type II), 92.9% (type III), and 82.4% (type IV) (p = 0.059). The overall adverse event rate was 16.4%, with pancreatitis (6.6%), bleeding (5.7%), and cholangitis (4.1%) showing no significant differences between the success and failure groups. Multivariate analysis identified MDP morphology (type II vs. I, OR: 0.256, p = 0.011) and active bleeding during NKP (OR: 0.117, p < 0.001) as independent predictors of failure. Conclusions: MDP morphology and intraprocedural bleeding are significant independent predictors of NKP failure in PAD patients with difficult biliary cannulation, whereas PAD type has no significant impact on NKP outcomes.