Potential of laparoscopic ultrasonography as an alternative to operative cholangiography in the detection of bile duct stones.

Background: Intraoperative cholangiography (IOC) is time consuming, requires radiation and sometimes fails. In contrast, laparoscopic ultrasonography (LUS) is a comparatively quick, safe and non-invasive technique. The aim of this study was to assess the potential of LUS as an alternative to IOC.

Methods: LUS was performed on 367 patients undergoing laparoscopic cholecystectomy. Laparoscopic duct exploration was performed in the presence of duct stones. Data were collected prospectively. The presence or absence and number of duct stones detected by LUS were recorded. The maximum bile duct diameter determined by LUS was compared with a preoperative ultrasonographic measurement according to age and the presence of duct stones. The final arbiter was the demonstration of stones removed at laparoscopic duct exploration (59 patients) or subsequently by endoscopic retrograde cholangiopancreatography (two patients).

Results: LUS visualized the CBD in 99 per cent of patients and the common hepatic duct in 92 per cent. It identified stones in 56 of the 61 patients with duct stones. No stones were demonstrated in the remaining 306 patients (sensitivity 92 per cent, specificity 100 per cent, positive predictive value 100 per cent, negative predictive value 98 per cent). LUS underestimated the total number of stones in 18 per cent of patients with common duct stones. The mean common bile duct diameter was 5.0 mm before operation and 5. 9 mm during the procedure in patients without duct stones, rising significantly to a mean of 9.2 mm before operation and 11.2 mm at LUS in those with duct stones (P < 0.0001).

Conclusion: The combination of the demonstration of duct stones and bile duct diameter measurement makes LUS a potential replacement for IOC. Improved demonstration of the common hepatic duct would be advantageous.