The aim of the present study was to compare the efficacy and safety of the knob-tipped knife and needle knife for precut papillotomy in difficult common bile duct (CBD)cannulation.

Precut sphincterotomy is an alternative technique used to facilitate CBD cannulation following the failure of conventional bile duct cannulation. Needle knife papillotomy is the most widely practiced precut technique. However,Pre-cutting the papilla with a needle-knife is difficult, requiring experience and dexterity to control the axis and depth of the cut. Due to the increased rate of complications associated with this procedure, including pancreatitis, hemorrhage, and perforation, it was recommended to be performed only by experienced endoscopists.

The knob-tipped knife, a novel instrument utilizing a 2mm or 1.5mm cutting knife, is usually used for endoscopic submucosal dissection (ESD). Its knob-shaped tip and nonadjustable length make the knife less likely to slip and penetrate the tissue during the resection. Since the process of precut papillotomy is similar to ESD, the precutting procedure with the knob-tipped knife may be easier to be performed, as well as be safer. The efficacy and safety of this instrument in precut papillotomy have not been reported. We therefore assessed the efficacy and safety of the knob-tipped knife in precut papillotomy in difficult CBD cannulation.

Inclusion Criteria:

• intact papilla and deep cannulation of the bile duct
• a standard wire-guided cannulation >10 minutes, OR Pancreatic contrast injections ≥3, OR Pancreatic deep wire pass ≥5

Exclusion Criteria:

• ampullary tumors
• Billroth II or Roux-en-Y anatomy
• prior endoscopic sphincterotomy(EST) or biliary stent
• choledochoduodenal fistulae