Study	Reason for exclusion
Aly 2001	This is a meta‐analysis of retrospective cohort studies. Patients undergoing both percutaneous and endoscopic biliary drainage were included.
Heslin 1998	This is an analysis of a retrospective data. 39 patients had ERCP with biliary stenting and 35 had direct surgery after ERCP.
Hodul 2003	This is an analysis of a retrospective data. 154 patients underwent ERCP with biliary stenting and 58 had direct surgery after ERCP.
Jagannath 2005	This is an analysis of a retrospective data. 74 patients underwent ERCP with biliary drainage and 70 had direct surgery after ERCP.
Marcus 1998	This is an analysis of a retrospective data. 22 patients underwent ERCP and biliary drainage and 30 had direct surgery after ERCP.
Martignoni 2001	This is an analysis of a retrospective data. 85 patients underwent ERCP and biliary stenting and 158 had direct surgical after ERCP.
Pisters 2001	This is an analysis of a retrospective hospital database. 98 patients underwent ERCP and biliary drainage and 93 had direct surgery after ERCP.
Sewnath 2001	This is an analysis of a retrospective data. 232 patients underwent ERCP and biliary stenting and 58 had direct surgery after ERCP.
Sohn 2000	This is an analysis of a retrospective data. Majority of patients underwent percutaneous biliary drainage and few had ERCP and biliary stenting.
Srivastava 2001	This is an analysis of a retrospective data. 50 patients underwent ERCP and biliary stenting and 67 had direct surgery after ERCP.

ERCP = endoscopic retrograde cholangiopancreatiocgraphy