Periampullary diverticula predispose to primary rather than secondary stones in the common bile duct.

Periampullary duodenal diverticula are known to be associated with an increased incidence of common bile duct stones. The nature of the association with gallstones remains uncertain. We have examined the incidence of periampullary diverticula and stones after cholecystectomy to determine whether the stones originate primarily in the common duct or migrate from the gallbladder under the influence of abnormal biliary motility. Six hundred and forty-one patients undergoing ERCP were studied. Ninety-five patients had diverticula (14.8%). Diverticula occurred more commonly in jaundiced patients, 47/95, (48.4%) than in patients with normal bilirubin 185/546 (33.8%) (p less than 0.01). Common duct stones were associated with the presence of a diverticulum in 41/95 patients (43%), compared with only 98/546 without a diverticulum (18%) (p less than 0.001). There was no difference in the incidence of common duct stones in association with a diverticulum between those who had had a cholecystectomy 20/41, and those with intact gallbladders, 21/54 (N.S.). Thus the absence of a gallbladder did not alter the high incidence of common duct stones. We conclude that the stones in the common duct are most likely to be primary stones which have formed as a result of periampullary dysfunction.