Laparoscopic ultrasonography in the evaluation of the biliary tree during laparoscopic cholecystectomy.

A prospective comparative study to evaluate operative cholangiography and laparoscopic ultrasonography in the detection of common bile duct (CBD) stones was undertaken in 54 patients undergoing laparoscopic cholecystectomy. Laparoscopic ultrasonography with a 7.5-MHz linear-array probe was performed before gallbladder mobilization. The incidence of choledocholithiasis at operation was 13 percent (seven patients). Cholangiograms were not obtained in six patients, one of whom had common duct stones identified by laparoscopic ultrasonography. Operative cholangiography detected five of the remaining six CBD stones with two false-positive examinations. Laparoscopic ultrasonography detected five of the seven stones with two false-positive examinations. The finding of a CBD diameter of 7 mm or greater and gallbladder stones of up to 3 mm in diameter by laparoscopic ultrasonography would have identified all patients with common duct stones and implies that none of these would have undergone false duct exploration. Laparoscopic ultrasonography is useful in the detection of choledocholithiasis.