Intrabiliary ultrasound applied to endoscopic extraction of choledochal stones.

Background: Although ERCP with endoscopic sphincterotomy is effective for choledocholithiasis, small residual stones may be missed by cholangiography, and intraductal ultrasound may improve detection and reduce recurrence. Objective: To observe the value of intraductal ultrasound (IDUS) in endoscopic extraction of choledocholithiasis. Methods: We retrospectively analyzed 148 patients with choledocholithiasis who underwent endoscopic retrograde cholangiopancreatography (ERCP) combined with endoscopic sphincterotomy (EST). IDUS was performed to observe whether there were any residual choledocholithiasis stones in those whose previous choledocholithiasis treatment indicated complete clearance; ERCP combined with EST was repeated to retrieve larger residual stones (≥3 mm). Postoperative follow-up was conducted to monitor the recurrence of choledocholithiasis and its influencing factors. Results: After 148 cases of endoscopic ERCP combined with EST, cholangiography confirmed the complete removal of choledochal stones. Notably, 61 cases were found to have residual stones, and 21 of them had residual stones ≥3 mm; these 21 cases were repeated until the stones were completely removed. After 3-24 months of follow-up, IDUS revealed that the stone recurrence rates were 8.33% (9/108) for 108 cases with complete stone removal and 62.50% (25/40) for 40 cases with residual stones. The difference was statistically significant ( Conclusions: IDUS can detect choledocholithiasis, particularly small stones (<3 mm), which are challenging to visualize with cholangiography. IDUS can assist in ERCP combined with EST to reduce the recurrence of postoperative stones.