New development of peroral cholangioscopy--evaluation of double-angle, oblique viewing cholangioscope.

Seven years have passed since the first report on peroral cholangioscopy by Takekoshi and Takagi (1) in Japan. Recently, several types of peroral cholangioscope with a forceps channel have been made for this treatment. However, the success rate of insertion of these instruments into the common bile duct was less than 50%. Therefore, in cooperation with Fuji-Photo-Optical Co. Ltd., we have made a new scope with the aim of facilitating insertion into the bile duct. Using this new scope, called a double-angle, oblique viewing cholangioscope, we obtain good orientation in the duodenum in en-face view and close inspection of the duodenal papilla, which makes possible easier insertion into the common bile duct. This new scope proved useful in basket removal of bile duct stone, or differential diagnosis between stones and carcinoma of the biliary tract.