IRCT20220905055884N1 IRCT 2022-10-05 Shahid Beheshti University of Medical Sciences Comparison of two bile duct cannulation methods in difficult ERCP cases ERCP Comparison of two preincisional sphincterotomy methods, needle knife fistulotomy versus transpancreatic sphincterotomy as path-breaking treatments in difficult ERCP conditions: a randomized controlled trial 2022-03-21 anticipated 128 Complete https://irct.ir/trial/65710 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Simple randomization method: In simple random sampling, each patient has an equal chance of being selected to be in one of the groups. In this study, patients were randomly selected and placed in the group of cannulation with pre cut sphincterotomy or cannulation with transpancreatic sphincterotomy, Blinding description: The patients who are in each group do not know about which bile duct cannulation method they have undergone, also in order to prevent abuse by the analyzing person, he is unaware of the allocation of study groups. N/A Obstruction of bile duct. Intervention 1: Intervention group: Patients who underwent fistulotomy with a needle knife above the papillary opening and then bile duct cannulation. Intervention 2: Intervention group: Patients underwent Trans-pancreatic precut sphincterotomy followed by bile duct cannulation. No - There is not a plan to make this available Justification or reason for not sharing IPD is Privacy and confidentiality