Study	Reason for exclusion
Angsuwatcharakon 2010	Inappropriate intervention: double‐guidewire cannulation versus precut sphincterotomy. Preliminary report (conference presentation) of Angsuwatcharakon 2012.
Angsuwatcharakon 2012	Inappropriate intervention: double‐guidewire cannulation versus precut sphincterotomy.
Artifon 2005	Preliminary report (conference presentation) of Artifon 2007.
Bailey 2006a	Preliminary report (conference presentation) of Bailey 2008.
Bailey 2006b	Post hoc analysis of two RCTs aimed to assess the effect of needle knife sphincterotomy (NKS).
Bailey 2006c	Preliminary report (conference presentation) of Bailey 2008.
Balderas 2011	Inappropriate intervention: double‐guidewire technique versus pancreatic duct stent, not a RCT.
Cennamo 2009	A meta‐analysis of five RCTs that compared primary biliary cannulation and post‐ERCP pancreatitis rates with the wire‐guided method and the standard cannulation technique.
Cha 2011	Inappropriate intervention: double‐guidewire versus transpancreatic precut sphincterotomy in difficult biliary cannulation.
Cheung 2009	A meta‐analysis of seven RCTs that compared guidewire‐guided with conventional contrast‐guided bile duct cannulation for the prevention PEP.
Choudhary 2009	A meta‐analysis of 6 RCTs that compared guidewire with conventional methods for cannulation rate and PEP.
Choudhary 2010a	A meta‐analysis of seven RCTs that compared pancreatic guidewire use for deep biliary cannulation with conventional guidewire use without pancreatic cannulation.
Choudhary 2010b	A meta‐analysis of seven RCTs that compared guidewires with conventional methods for cannulation rate and PEP.
Cote 2010	Inappropriate intervention: pancreatic duct guidewire vs. pancreatic duct stent.
de Tejada 2007	Inappropriate intervention: double‐guidewire technique vs. standard cannulation technique. Preliminary report and duplicate data of de Tejada 2009.
de Tejada 2009	Inappropriate intervention: double‐guidewire technique vs. standard cannulation technique.
Epstein 2009	A systematic review of three RCTs that compared wire‐guided cannulation with conventional contrast injection in ERCP.
Ito 2008	Inappropriate intervention: double‐guidewire technique, not a RCT.
Ito 2010	Not a RCT.
Kamata 2011	Not a RCT.
Lee 2004	A case series, not a RCT.
Madhoun 2009	A meta‐analysis of five RCTs that compared wire‐guided cannulation technique with conventional cannulation as a strategy to reduce PEP.
Maeda 2003	Inappropriate intervention: pancreatic duct guidewire versus persistence with a conventional catheter in difficult cases of selective bile duct cannulation.
Mariani 2012	Not a RCT.
Nakai 2011	Not a RCT
Nambu 2009	Preliminary report (conference presentation) of Nambu 2011.
Park 2008	Preliminary report (conference presentation) of Lee 2009.
Shao 2009	A meta‐analysis of four RCTs that compared wire‐guided cannulation with conventional contrast‐assisted cannulation for the incidence of PEP.
Trifan 2011	Not a RCT.
Zheng 2010	Inappropriate intervention: double‐guidewire versus standard cannulation technique.