Preoperative ultrasonographic assessment of the number and size of gallbladder stones: is it a useful predictor of asymptomatic choledochal lithiasis?

Abstract

To evaluate whether preoperative ultrasonographic assessment of the number and size of gallbladder stones can identify patients at increased risk of having asymptomatic common bile duct stones. Ultrasonographic data for 300 consecutive patients undergoing laparoscopic cholecystectomy were analyzed. Patients were divided into a group in which multiple small (< or = 5 mm) or multiple variably sized (both < or = 5 and > 5 mm) gallbladder stones were present ("positive" stones) and a group with multiple large (> 5 mm) or single gallbladder stones, considered "negative." The ultrasonographic description was compared with surgical findings; finally, the prevalence of asymptomatic common bile duct stones in the 2 groups was compared. Ultrasonographic classification of gallbladder stones was confirmed at surgery in 285 cases (95%). Asymptomatic common bile duct stones were diagnosed in 9.5% of patients with an ultrasonographic diagnosis of positive gallbladder stones and in only 2.3% of patients with a diagnosis of negative gallbladder stones (P < .05). Ultrasonography is able to accurately show gallbladder stones; the appearance of multiple small and variably sized gallbladder stones represent a risk factor for synchronous asymptomatic common bile duct stones.