S3213 Spontaneous Choledochoduodenal Fistula Post-Cholecystectomy: Successful Endoscopic Management of a Rare Complication Using Cholangioscopy and Lithotripsy

Introduction: Spontaneous choledochoduodenal fistula (CDF) is a rare complication of chronic choledocholithiasis, particularly in post-cholecystectomy patients. Management is often challenging due to anatomic distortion, stone burden, and increased procedural complexity. We present a unique case of post-cholecystectomy cholangitis with incidental spontaneous CDF and refractory bile duct stones, successfully managed with advanced endoscopic techniques including direct visualization cholangioscopy and electrohydraulic lithotripsy (EHL). Case Description/Methods: Seventy-five-year-old woman with hypertension, diabetes, and prior cholecystectomy presented with confusion, lethargy, fever, epigastric pain, and vomiting. Labs showed leukocytosis (15.5 × 10⁹/L), transaminitis (AST 780, ALT 458 U/L), total bilirubin 2.2 mg/dL, and lactate 2.8 mmol/L. Computed tomography and ultrasound revealed bile duct dilation and choledocholithiasis. She met Tokyo Guidelines 2018 criteria for grade II cholangitis. Initial endoscopic retrograde cholangiopancreatography (ERCP) revealed a spontaneous choledochoduodenal fistula, periampullary diverticulum, and multiple common bile duct (CBD) stones. A biliary sphincterotomy, balloon sweep, and placement of 1 plastic and 1 bare metal stent were performed. Stones were seen exiting through the fistula, bypassing the ampulla. She improved but was readmitted 2 weeks later with recurrent cholangitis and persistent ductal stones on imaging. A second ERCP with direct visualization cholangioscopy revealed large, densely calcified stones. EHL was used for fragmentation, but multiple balloon catheters ruptured due to stone burden. A distal CBD stricture was noted. A fully covered self-expanding metal stent was placed for both biliary drainage and fistula tamponade. The patient improved, with normalization of liver enzymes and resolution of symptoms. Discussion: This case highlights a rare instance of spontaneous CDF in a post-cholecystectomy patient. Fistula formation likely stemmed from prolonged biliary obstruction and chronic inflammation. Endoscopic management was complicated by altered anatomy, periampullary diverticulum, and a high stone burden. Cholangioscopy enabled direct visualization and successful EHL. Covered metal stenting maintained ductal patency and facilitated fistula closure. This approach avoided the need for surgery in a high-risk elderly patient. In select patients, minimally invasive, advanced endoscopic modalities such as cholangioscopy and EHL can provide definitive therapy, even in complex biliary anatomy, and may obviate surgical intervention.