Abstract: Objective To analyze the clinical data of patients with common bile duct stones accompanied by periampullary diverticulum, investigate the characteristics of the stones, ERCP-related procedural parameters, and complication rates, and provide evidence-based guidance for clinical practice. Methods A total of 120 patients with CBD stones who underwent ERCP between December 2022 and December 2024 were retrospectively analyzed in our hospital. Among them, 21 patients (17.5%) had concomitant PAD. General clinical characteristics, ERCP-related procedural data, and complications were compared between patients with and without PAD. Results Compared with patients without PAD, those with PAD had significantly higher rates of prior cholecystectomy, longer stone length, greater number of stones, and larger CBD diameter (P<0.05). PAD patients also had significantly larger balloon dilation diameters, increased intraoperative bleeding, higher rates of plastic stent placement and nasobiliary drainage, increased need for mechanical lithotripsy, lower stone clearance rates, greater difficulty in cannulation, longer cannulation time, and prolonged procedure time compared to those without PAD (P<0.05). Complications during treatment included post-ERCP pancreatitis, biliary tract infection, periampullary perforation, and hyperamylasemia. PAD patients showed a significantly higher incidence of hyperamylasemia and total complication rate compared to those without PAD (P<0.05). Conclusion PAD, as a common but complex anatomical variation, is closely associated with the formation of CBD stones and significantly increases the technical difficulty of ERCP and the risk of postoperative complications.

Key words: Common bile duct stones, Periampullary diverticulum, Hyperamylasemia