“…This method cannot distinguish the cystic duct from the common bile duct, which increases the risk of placing the stent in the cystic duct, with failure of biliary decompression and potential ob− struction or perforation of the cystic duct. The possibility of loop− ing of the guide wire, leading to improper placement of the stent, has also been suggested [12], especially for obstructive lesions of the proximal common bile duct, where a failure rate close to 50 % has been reported [11]. Less commonly, transabdominal ultra− sound has been used for confirmation of biliary cannulation [ 1,3,5].…”