Prospective analysis of a scoring system to predict choledocholithiasis.

Abstract

The management of choledocholithiasis in the laparoscopic era remains debatable. A common policy is to perform preoperative endoscopic retrograde cholangiopancreatography (ERCP) on patients suspected of having common bile duct (CBD) stones, using standard risk criteria. The aim of this study was to evaluate prospectively a scoring system designed to improve the accuracy of CBD stone prediction before laparoscopic cholecystectomy. Known clinical, biochemical and radiological risk factors for CBD stones were analysed retrospectively in 233 patients. The presence (n = 77) or absence (n = 156) of CBD stones was determined by preoperative ERCP and/or laparoscopic cholangiography. Using multivariate analysis, the significant risk factors for CBD stones were identified and a new preoperative scoring system was developed. A score of 3 or more was taken as the cut-off point to suggest CBD stones and the need for preoperative ERCP. This scoring system was then tested prospectively in 211 consecutive patients with symptomatic gallstones requiring surgery. Patients whose bile ducts could not be demonstrated by ERCP or operative cholangiography were excluded. Fifty-five patients scored 3 or more (predicted ERCP rate of 29 per cent), of whom 23 (42 per cent) had proven CBD stones. Intraoperative cholangiography was successful in 87 per cent. Five patients (4 per cent) who scored less than 3 had small stones (less than 5 mm) demonstrated at operative cholangiography. The overall sensitivity and specificity of this scoring were 82 and 80 per cent respectively. Formal risk assessment of the presence of CBD stones using this scoring system is simple and may be used for preoperative selection of patients for biliary tract imaging by magnetic resonance cholangiography or ERCP.