Fig. 1

a Difficult biliary cannulation was due to failure of 10 attempts at duodenal papilla; (b) Limited precut sphincterotomy was performed with the extent of cutting was less than half the length of the papillary mound; (c) Common bile duct stone was found after successful biliary cannulation; (d) Endoscopic papillary balloon dilation was performed after limited precut sphincterotomy; (e and f) Common bile duct stone was extracted by retrieval balloon