[Ultrasonography in the preoperative assessment of candidates for laparoscopic cholecystectomy: examination technique and results].

Laparoscopic cholecystectomy needs a more specific preoperative diagnostic approach than open cholecytsectomy. We investigated the role of US in the preoperative assessment of patients candidate to laparoscopic cholecystectomy. Two hundred patients were examined and then submitted to laparoscopic cholecystectomy regardless of US results: the surgical approach had to be changed from laparoscopy to laparotomy only in 10 of them. We focused our study on two major parameters to reduce the surgical risk: the anatomical study of the so-called "Calot's triangle" (the hepatic artery, common duct and cystic duct) and the study of the gallbladder bed and of pericystic structures. In the study of gallbladder walls and bed, US had high sensitivity (100%) and diagnosed no false negatives and 11 false positives of pericholecystitis (94.5% specificity), with a trend toward overstaging; in these 11 cases, gallbladder wall thickening was seen but the organ was not particularly difficult to remove at surgery. In cystic duct studies, we correctly diagnosed 6 abnormalities (3 cystic duct stones, 2 anatomical variants and 1 anatomical variant plus stone), with no false-positive and 2 false-negative diagnoses of abnormal insertion (75% sensitivity and 100% specificity). The common duct was shown along its whole course in 80% of cases; both sensitivity and specificity were 100% in dilatation detection, while the presence of stones was diagnosed with 70% sensitivity and 100% specificity.