Prediction of common bile duct stones: its validation in laparoscopic cholecystectomy

Although perioperative cholangiography is valuable and highly accurate in the detection of common bile duct (CBD) stones, its routine use is controversial, particularly in the era of the laparoscopic cholecystectomy because of its inherent disadvantages. The purposes of this retrospective and prospective study on cholelithiasis were to identify patients at low risk for CBD stones and to assess the validity of the low risk criteria.

For the first, retrospective study, 15 significant preoperative clinical, biochemical and sonographic variables were selected from 561 consecutive patients who underwent conventional cholecystectomy with routine intraoperative cholangiography (IOC) for cholelithiasis from January 1985 to December 1993, and independent risk factors predicting the presence of CBD stones were determined by multivariate logistic regression analysis. For the second, prospective study, from April 1994 to September 1995, a laparoscopic cholecystectomy (LC) was performed without perioperative cholangiography in 153 consecutive patients with the primary low risk criterion (sonographic CBD diameter < 10 mm) determined by the first study. All of the LC patients were followed-up for a median duration of 12 months (range 4 to 21 months).

In the first study, CBD stones were present in 95 (16.9%) patients. The most important independent predictor was a dilated CBD (> 10 mm). Three levels of risk were determined: (1) the low risk group (73.8% of the patients), in which the CBD was not dilated and the prevalence of CBD stones was 1.5% (6/408); the moderate risk group (7.8% of the patients), in which there was a dilated CBD with normal liver function tests and a prevalence of stones of 48.8% (21/43); and the high risk group (18.4%), in which there was a dilated CBD and abnormal liver function tests and a prevalence of stones of 66.7% (68/102). In the second study, two cases (1.4%) of symptomatic overlooked CBD stones were found on endoscopic retrograde cholangiography and retrieved by endoscopic sphincterotomy on postoperative days 18 and 20, respectively.

Preoperative assessment in cases of cholelithiasis can determine which patients are at low risk for having CBD stones, thereby avoiding unnecessary perioperative cholangiography. This selectivity is also valid in LC, since the incidence of symptomatic, overlooked CBD stones was very low.