Management of choledocholithiasis with an ultraslim cholangioscope in a patient with possible anaphylaxis to contrast medium

Adverse reactions to contrast medium during endoscopic retrograde cholangiopancreatography (ERCP) are rare [1]; however, once they occur, the subsequent ERCP becomes challenging. Although alternatives using carbon dioxide or gadolinium exist [2] [3], resolution issues persist. Stone removal using a cholangioscope without fluoroscopy or contrast media in pregnant patients has been reported [4]; however, due to the thickness and rigidity of conventional cholangioscopes, this remains problematic. We report on common bile duct (CBD) stone removal without contrast media, using a novel ultraslim cholangioscope with a tip diameter of 2.3 mm (DRES Slim Scope; Japan Lifeline Co., Ltd., Tokyo, Japan) ([Fig. 1]) [5].