Choledocholithiasis: a prospective study of spontaneous common bile duct stone migration

Background: The rate of spontaneous migration of bile duct stones through t he duodenal papilla is not well known. Endoscopic retrograde cholangiograph y (ERC) has been the standard method to diagnose bile duct stones, but accu mulating data show there is a good agreement between ERC and endoscopic ult rasonography (EUS), The aim of the study was to evaluate the incidence and time course of stone migration in patients with bile duct stones by analyzi ng discrepancies between EUS and ERC as a function of the elapsed time betw een these two procedures, Stone migration was considered as the absence of stones at time of ERC regardless of the number of stones seen at EUS. Methods: The main criterion for inclusion was the presence of bile duct sto ne as shown by EUS, Ninety-two consecutive patients were prospectively incl uded in this study. Results: Choledocholithiasis was absent at ERC in 12 patients. In univariat e analysis, presence of gallbladder was significantly associated with an in creased rate of stone migration (correction for multiple testing would remo ve this statistical significance). The size of the stone was the only indep endent factor to predict migration, Conclusion: Migration occurred in about 21% of cases within 1 month. Our st udy emphasizes the need to analyze carefully the results of comparative ima ging studies of bile duct stones.