Which does not contribute to enterobiliary fistula

Internal biliary fistula Cholecystoduodenal fistula(72-80%) are MC biliary enteric fistulas followed by cholecysticolic fistula (8-12%). Etiology Calculous biliary tract disease (90%). Duodenal ulcer(6%) Neoplasm, trauma, Parasitic infestation and congenital anomalies (4%) Ref : Sabiston 20th edition Pgno :1507