Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12876-016-0486-4/MediaObjects/12876_2016_486_Fig1_HTML.gif)
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