Mirror Image Technique in Choledocholithiasis: ERCP in Situs Inversus With a Forward Viewing Endoscope

Abstract

Situs inversus is a congenital disease manifested by complete or partial reversal of anatomy. It occurs during early gestation and typically results in normal function. However, performing procedures on such patients is technically challenging due to their abnormal anatomies. Herein we describe a challenging endoscopic case of choledocholithiasis in a patient with situs inversus. A 45-year-old male with history of abdominal situs inversus from polysplenia syndrome presented for epigastric pain, nausea and vomiting. Vital signs were stable and exam was notable for diffuse tenderness in the epigastrium without jaundice or Murphy's sign. Pertinent labs showed a negative troponin, AST 399 U/L, ALT 385 U/L, alkaline phosphatase 425 U/L, total bilirubin 2.5 mg/dL, direct bilirubin 1.8 mg/dL, and WBC 13.6 K/uL with neutrophilic predominance. CT scan revealed abdominal situs inversus with multiple splenules, gallbladder distention without wall thickening or pericholecystic fluid, and an obstructing stone with common bile duct (CBD) dilatation to 2.1 cm. ERCP was performed by placing the patient in the right lateral decubitus with the endoscopist standing to the right of the patient. A TJF scope was advanced into the duodenum but retracted and was unable to be re-advanced due to the anatomy. The TJF scope was switched out for a forward viewing endoscope which was successfully advanced to the major papilla. The bile duct was then cannulated with the short-nosed traction sphincterotome. Injected contrast showed adequate ductal flow and dilated main bile duct with a 12 mm stone. Biliary sphincterotomy was made with traction sphincterotome using ERBE electrocautery and a plastic double pigtail stent was placed into the CBD allowing free-flow of the bile. Repeat ERCP for mechanical lithotripsy was scheduled and the patient was discharged. Situs inversus is a rare congenital disease that presents with partial to complete reversal of anatomy. Our case utilizes the mirror image technique employed in prior reports. This technique positions the patient in the right lateral decubitus and the endoscopist on the right of the patient. Prior cases were notable for ERCP failure rates of up to 25% in situs inversus. This case was successfully performed by utilizing mirror image technique with a forward viewing 1T scope. Though such cases are rare, we present this case to highlight the difficulties met by changes in anatomy and techniques used to overcome such challenges.2160_A Figure 1. Abdominal CT demonstrating stone obstructing common bile duct (Red Arrow).2160_B Figure 2. Abdominal CT demonstrating intrahepatic ductal dilatation (Red Arrows), contrast filled stomach (Blue Arrow), and liver situated on left side of the body (Green Arrows).2160_C Figure 3. Abdominal CT demonstrating extrahepatic ductal dilatation (Red Arrow), and multiple splenules (Blue Arrows).