A 58-year-old woman presents with painless jaundice, dark urine, and pale stools. Laboratory investigations show conjugated hyperbilirubinemia (total bilirubin 5.2 mg/dL) and elevated alkaline phosphatase. Abdominal ultrasound reveals gallstones and a dilated common bile duct (CBD) measuring 11 mm. ERCP is performed with a side-viewing duodenoscope. The cholangiogram demonstrates the finding marked **D** — a round 12 mm filling defect in the distal CBD with a meniscus sign, consistent with an impacted choledocholithiasis. Which of the following is the most appropriate next step in the management of this patient?

Explanation

## Why endoscopic biliary sphincterotomy followed by balloon or basket extraction is correct The finding marked **D** — a round 12 mm filling defect in the distal CBD with a meniscus sign — represents an impacted choledocholithiasis that is amenable to endoscopic therapy. According to ASGE Choledocholithiasis Guidelines 2019 and Tokyo Guidelines 2018, ERCP is the diagnostic and therapeutic procedure of choice for CBD stones. The patient has HIGH-RISK features (bilirubin >4 mg/dL, dilated CBD on ultrasound, and imaging confirmation of a stone), warranting direct ERCP. The standard ERCP technique involves: (1) cannulation of the biliary tree with a sphincterotome over a guidewire, (2) endoscopic biliary sphincterotomy (EBS) to enlarge the papillary orifice by incising the sphincter of Oddi via cautery, and (3) stone extraction using a balloon catheter (Fogarty-like) or Dormia basket for stones <15 mm. The 12 mm stone in this case is ideal for balloon or basket extraction after sphincterotomy. This approach is minimally invasive, has high success rates (>90%), and avoids surgical morbidity. ## Why each distractor is wrong - **Percutaneous transhepatic cholangiography with external drainage**: PTC is reserved for cases where ERCP has failed, is contraindicated (e.g., altered anatomy post-surgery), or when urgent drainage is needed in cholangitis and ERCP is unavailable. This patient has a patent ampulla of Vater accessible by ERCP, making PTC unnecessary as a first-line intervention. - **Immediate surgical choledochotomy and stone extraction**: Surgical intervention is rarely indicated in the modern era for uncomplicated CBD stones. Surgery is reserved for: (1) failed ERCP with persistent symptoms, (2) anatomical contraindications to ERCP (e.g., duodenal obstruction), or (3) complications such as free perforation. This patient has no such indications and should undergo endoscopic therapy first. - **Placement of a biliary stent without sphincterotomy and referral for interval ERCP**: Biliary stent placement without sphincterotomy is used as a temporary measure for cholangitis when the stone cannot be immediately cleared (bridge to definitive therapy) or when the patient is too ill for prolonged endoscopy. However, in a stable patient with a straightforward 12 mm stone, sphincterotomy and immediate extraction is the standard of care and avoids the need for a second procedure. **High-Yield:** ERCP with endoscopic biliary sphincterotomy and stone extraction is first-line therapy for choledocholithiasis; stones <15 mm are extracted with balloon or basket after sphincterotomy; stones >15 mm require mechanical lithotripsy or cholangioscopy-guided lithotripsy. [cite: ASGE Choledocholithiasis Guidelines 2019; Tokyo Guidelines 2018; Sabiston Surgery 21e Ch 55]