Biliary fistulas are broadly classified into: external and internal fistulas. Internal biliary fistulas are further classified 
into, bilio-enteric, bilio-biliary, bilio-vacular, and bilio-bronchial. (1) 
Both external and internal biliary fistulas can occur due to some disease (spontaneous or pathological) or trauma (either 
iatrogenic or external trauma). While external fistulas are more frequently post-traumatic, internal fistulas are more 
commonly spontaneous (1) A third etiology for biliary fistulas is the intentionally created fistulas for therapeutic purposes. 
This latter group will not be included in this article. 
Spontaneous fistulas may be associated with the following diseases: gallstones, peptic ulcer, bile duct cancer, hepatic 
abscess, hydatid cyst, amebic abscess, and rare diseases (T.B., mucomycosis, polyarteritis nodosa), (2, 3).
Iatrogenic fistulas commonly follow the following procedures: cholecystostomy, cholecystectomy, choledochotomy, biliaryintestinal anastomoses, drainage of intra-abdominal collections, interventional radiology, liver surgery, and endoscopic 
sphincterotomy (1). 
Any part of the biliary tree can be involved in fistulas including: the gallbladder, common bile duct, common hepatic duct, 
cystic duct remnant, right or left hepatic ducts and intra-hepatic biliary radicles (4,1). 
An "uncontrolled fistula" denotes fistula formation with intraperitoneal leakage and collection of bile. Meanwhile, a 
"controlled fistula" denotes a fistula with drainage to the exterior through the abdominal wall without any significant intraabdominal collection (1).