Introduction: Situs inversus totalis (SIT) is a rare congenital anomaly in which internal organs are mirrored along the sagittal plane. The incidence is 1.25-16.7/100,000 individuals, with a slight male predominance. Altered anatomy in SIT presents a challenge in performing endoscopic retrograde cholangiopancreatography (ERCP). Technical difficulty is greater due to an inverted endoscopic view, altered fluoroscopic orientation, and a different direction of common bile duct (CBD) cannulation. Most data on the performance of ERCP in SIT are based on clinical cases.

Case 1: In July 2025, a 78-year-old female patient with known gallstones was admitted for acute cholangitis, Tokyo grade 1. Magnetic resonance imaging (MRI) revealed choledocholithiasis, and ERCP was indicated. However, the patient's SIT and other co-morbidities (non-ischemic dilated cardiomyopathy, chronic kidney disease, chronic atrial fibrillation on anticoagulant therapy, and ascending aortic aneurysm) posed a challenge. Firstly, gastroscopy was performed to assess the anatomy of the upper gastrointestinal tract. ERCP was performed in standard settings with the patient in the left semi-prone position and the endoscopist on the right side of the table. A technique with 180˚  rotation in the stomach and shortening of the endoscope in the duodenum in the opposite direction from usual was used. With standard cannula and guide wire cannulation of the CBD was achieved and confirmed with fluoroscopy and bile aspiration. Sphincterotomy was performed using a standard papillotome and manipulation of the duodenoscope tip.  Successful balloon extraction of the stone followed with no complications.

Case 2: In September 2025, a 93-year-old male patient with SIT was admitted with signs of acute cholangitis, Tokyo grade 2. CT on admission showed small gallbladder stones and dilatation of the CBD to 12 mm with a thickened wall. We proceeded with ERCP, which was performed in the same position as previously described, and the same 180˚  rotation in the stomach technique was used. In this case, cannulation of CBD was achieved using a standard papillotome and guide wire, and successful balloon extraction of microliths following sphincterotomy.  We performed stenting using a biodegradable biliary stent, and no complications occurred.

Conclusion: SIT presents a significant anatomical challenge during endoscopic procedures. The literature provides insufficient evidence to determine the optimal approach, and currently, no standard patient or endoscopist position for ERCP in SIT is recommended. Recognizing the reversed anatomy and the experience of the endoscopist are essential for safe and effective ERCP performance.