Descending sphincterotomy of the papilla of Vater through the T-drain under endoscopic view. Variants of endoscopic papillotomy (EPT).

An indwelling T-drain is a valuable access to the common bile duct if the conventional EPT fails in the case of choledocholithiasis. It is often easier to cannulate the duodenal papilla from the common bile duct than from the duodenum. A papillotome of the Erlangen type introduced through the T-drain into the papilla spontaneously has the correct cutting direction.