Accurate Evaluation of Residual Common Bile Duct Stones by Endoscopic Ultrasound: A Two-Step Check Method for Residual Stone Clearance

Residual common bile duct (CBD) stones occasionally become symptomatic after stone removal with endoscopic retrograde cholangiopancreatography (ERCP) upon removal of the endoscopic biliary stent (EBS). An accurate evaluation of residual stones before stent removal is necessary. This study evaluated a new two-step check method using endoscopic ultrasound (EUS) for the detection of residual stones after ERCP stone removal.Fifty-six patients who underwent CBD stone removal and EBS placement were prospectively enrolled. Residual stones were evaluated by the check method. EBS was removed at the time of the check method or at a later time of residual stone removal. The primary outcome was to evaluate the efficacy of this check method.Residual CBD stone/sludge was detected in 20 of 56 patients (35.7%; stones: 28.6%, sludge: 7.1%) by the check method and removed by the ERCP procedure at a later time. After stent and final stone removal, patients were followed for an average of 211 days; cholangitis recurred in only 1.8% of patients. There were no adverse events associated with the check method. Temporary EBS prevented the recurrence of cholangitis by residual stone and caused no adverse events in the pancreatobiliary tract until the two-step check method (median, 113 days; range, 17-232 days).The new check method may be ideal and feasible for EBS removal because recurrences are very rare when a clear CBD has been verified, and an additional ERCP procedure is also possibly avoided.