Association of periampullary diverticula with primary choledocholithiasis but not with secondary choledocholithiasis

Background and Study Aims: Several endoscopic studies have reported an association between periampullary diverticula and biliary calculi, but the results are inconsistent when the anatomic site of the stones is considered. The aims of our study are to evaluate the association between periampullary diverticula and gallstones according to their site and to clarify the origin of the common bile duct stones by analyzing their composition. Patients and Methods: During a period of 10 months, 611 of 632 consecutive patients having endoscopic retrograde cholangiopancreatography (ERCP) were prospectively enrolled, The data about periampullary diverticula and gallstones were analyzed according to the site of the stones. The stones were initially grouped on the basis of their gross morphology and cross-sectional appearance, and finally analyzed by quantitative infrared spectroscopy. Results: Diverticula were found in 165 of 611 cases (27%) and the incidence increased with age (p < 0.01). The incidence of gallbladder or common bile duct stones was higher in patients with periampullary diverticula (73/165, 44%) than without (130/446, 29%) (p < 0.01), Considering the site of the gallstones, this significance was found only in patients with common bile duct stones not associated with gallbladder stones (p < 0.001). Of the 30 who had gallstones only in the common bile duct, 32 gave a history of cholecystectomy more than tno years previously and had been free of symptoms postoperatively, and on analysis most of the stones (30/36,83%) were brown pigment stones, These therefore were assumed to be primary common bile duct stones. The common bile duct stones with associated gallbladder stones were identical to their paired gallbladder stones in gross and cross-sectional appearance and chemical composition. They were assumed to be secondary common bile duct stones and the difference in the incidence of calculi according to the presence of diverticula was not significant. Conclusion: The incidence of gallstones was significantly higher in periampullary diverticula, and when the site and the origin of the gallstones was considered the association between diverticula and gallstones was significant in patients with primary common bile duct stones but not with the secondary ones.