A biliary fistula is a type of fistula in which bile flows along an abnormal connection from the bile ducts into a nearby hollow structure. Types of biliary fistula include:bilioenteric fistula: abnormal connection to small bowel, usually duodenum. thoracobiliary fistula: abnormal connection to pleural space or bronchus (rare). bronchobiliary fistula: pathological communication between a bronchus and the biliary tract.