Common duct diameter as an independent predictor of choledocholithiasis: is it useful?

We have evaluated the value of ultrasonographic measurement of common duct diameter in isolation from other predictors of choledocholithiasis. A cohort of 223 patients who did not have a history of jaundice or pancreatitis and had normal liver function tests underwent pre-operative ultrasound of the common hepatic duct and then had elective (open) cholecystectomy with operative cholangiography. One hundred and ninety-one (86%) of all patients had a normal (< or = 5 mm) common duct and of these only 12 (6%) had common duct calculi. Of the 32 patients who had a common duct diameter greater than 5 mm on pre-operative ultrasonography, 12 (37.5%) patients had ductal calculi. A pre-operatively dilated duct on ultrasonography has a high chance of containing stones and should be considered as a strong indication for pre-operative bile duct imaging or operative cholangiography.