 The surgery involves exposing the porta hepatis (the area of the liver from which bile should drain) by radical excision of all bile duct tissue up to the liver capsule and attaching a Roux-en-Y loop of jejunum to the exposed liver capsule above the bifurcation of the portal vein creating a portoenterostomy.The rationale for this approach is that minute residual bile duct remnants may be present in the fibrous tissue of the porta hepatis and thus provide direct connection with the intrahepatic ductule system to allow bile drainage.This procedure was developed in 1951 by Japanese biliary and hepatic pediatric surgeon Morio Kasai (1922–2008).