A comparison of laparoscopic ultrasound with digital fluorocholangiography for detecting choledocholithiasis during laparoscopic cholecystectomy

Abstract

Background: Laparoscopic ultrasound is an alternative to operative cholangiogram for evaluation of the common bile duct (CBD) during laparoscopic cholecystectomy. It is a safe, fast, and reliable method for detecting choledocholithiasis. Methods: We prospectively evaluated the sensitivity and specificity of laparoscopic ultrasound (LUS) and digital fluorocholangiogram (DFCG) in a three-phase study of 360 consecutive patients. Results: In phase I, 140 patients undergoing laparoscopic cholecystectomy had LUS performed first, followed by DFCG. Thirteen patients had CBD calculi identified on LUS. Four patients with confirmed (two cases) or presumed (two cases) CBD calculi on DFCG were not identified on LUS. Thus, the specificity of LUS was 100%, whereas the sensitivity was 76.5%. DFCG had four false positives, for a sensitivity of 100% with a specificity of 96.7%. LUS was performed, on average, in 6.6 min, whereas DFCG required 10.9 min to perform. In phase II, the infusion of saline through a cystic duct catheter was performed in instances where the distal CBD could not be well seen. This maneuver distended the intrapancreatic portion of the CBD, allowing better visualization. Nine stones were identified on LUS in 78 patients, increasing the sensitivity to 100%. One false positive DCFG was encountered, resulting in a sensitivity of 100% and a specificity of 98.6%. In phase III, we performed routine LUS and used DFCG only in select cases. The sensitivity and specificity for LUS were 95.7% and 100%, respectively, whereas DFCG had a sensitivity of 95.2% and a specificity of 100%. One patient in phase III has returned 11 months post-op with a CBD stone. This was initially missed on LUS, DFCG, and postoperative ERCP. The sensitivity and specificity in all 360 patients were 90% and 100% for LUS and 98.1% and 98.1% for DFCG, respectively. A total of five CBD stones were missed by LUS, four early in the study (phase I). One missed on LUS in phase III was also missed by DFCG and ERCP. Conclusions: LUS is a reliable alternative to DFCG during laparoscopic cholecystectomy (LC). With experience, it is as sensitive as DFCG and more specific. It is more rapidly performed than cholangiography.