['The mechanism of pancreatitis development following endoscopic papillary balloon dilation (EPBD) remains unknown. Antegrade dilation with percutaneous transhepatic papillary balloon dilation (PTPBD) allows the removal of bile duct stones or fragments during percutaneous choledochoscopic lithotomy, with less mechanical trauma to the papilla than with EPBD-mediated stone removal.', 'A total of 56 patients with bile duct stones underwent antegrade dilation with PTPBD from March 2006 to February 2011. A total of 208 patients with common bile duct stones underwent retrograde dilation with EPBD during the same period. The conditions of papillary balloon dilation were identical in both groups. The frequencies of pancreatitis and hyperamylasemia were compared in both groups.', 'Pancreatitis occurred in 14 (6.7%) of 208 patients in the EPBD group (mild, nine; moderate, four; severe, one). There was no case of pancreatitis among 56 patients in the PTPBD group (P < 0.05). Hyperamylasemia developed in significantly more patients treated in the EPBD group (62, 29.8%) compared with the PTPBD group (4, 7.1%; P < 0.05). Complete bile duct clearance was achieved in 98.2% of PTPBD group and 97.1% of EPBD group.'] Is papillary balloon dilation itself a cause of post-endoscopic retrograde cholangiopancreatography pancreatitis ; results of anterograde and retrograde papillary balloon dilation?