A novel biliary cannulation method for difficult cannulation cases using a unique, uneven, double-lumen cannula (Uneven method)

The utility of pancreatic duct guidewire (P-GW) placement techniques, including the contrast-medium method and the contrast-free wire-guided cannulation method (i. e. the "double-guidewire method" [D-GW]), has been reported for selective biliary cannulation in patients in whom performing cannulation of the bile duct is difficult [1] [2] [3] [4] [5]. However, P-GW placement often disturbs the approach to the bile orifice. Moreover, it is sometimes difficult to insert the catheter or guidewire in the direction of the bile duct, which delays biliary cannulation.