Assessment of residual bile duct stones with use of intraductal US during endoscopic balloon sphincteroplasty: comparison with balloon cholangiography

Background: We sought to determine the utility of intraductal ultrasonograp hy (IDUS) in detecting residual bile duct stones during endoscopic balloon sphincteroplasty. Methods: Eighty-one consecutive patients with bile duct stones who underwen t IDUS during endoscopic balloon sphincteroplasty were studied. IDUS was pe rformed with a thin-caliber ultrasonic probe (diameter 2.0 mm, frequency 20 MHz) by a transpapillary route after stone extraction. When IDUS or balloo n-retrograde cholangiography suggested residual stones, the bile duct was c leared again with a Dormia basket. Extraction of the stones was confirmed b y direct duodenoscopic visualization. Videotapes of IDUS and cholangiograms were reviewed retrospectively without knowledge of the results of other di agnostic modalities. Results: In 27 of 81 patients (33%), IDUS detected small residual stones no t seen on cholangiography. When stones were fragmented with mechanical lith otripsy, the accuracy of IDUS in detecting small residual stones was signif icantly greater than that of balloon-endoscopic retrograde cholangiography (95% vs 50%, p < 0.001). When the bile duct was greater than 10 mm in diame ter, the accuracy of IDUS in detecting small residual stones was significan tly greater than that of cholangiography (92% vs. 56%, p < 0.001). Conclusions: IDUS is useful for detecting small residual bile duct stones d uring endoscopic balloon sphincteroplasty when stones are fragmented by mec hanical lithotripsy or when there is evidence of a dilated bile duct (>10 m m).