Primary needle-knife fistulotomy for preventing post-endoscopic retrograde cholangiopancreatography pancreatitis: Importance of the endoscopist's expertise level

BACKGROUND Needle-knife fistulotomy (NKF) is used as a rescue technique for difficult cannulation. However, the data are limited regarding the use of NKF for primary biliary cannulation, especially when performed by beginners. AIM To assess the effectiveness and safety of primary NKF for biliary cannulation, and the role of the endoscopist's expertise level (beginner vs expert). METHODS We retrospectively evaluated the records of 542 patients with naive prominent bulging papilla and no history of pancreatitis, who underwent bile duct cannulation at a tertiary referral center. The patients were categorized according to the endoscopist's expertise level and the technique used for bile duct cannulation. We assessed the rates of successful cannulation and adverse events. RESULTS The baseline characteristics did not differ between the experienced and less-experienced endoscopists. The incidence rate of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) was significantly affected by the endoscopist's expertise level in patients who received conventional cannulation with sphincterotomy (8.9% vs 3.4% for beginner vs expert, P = 0.039), but not in those who received NKF. In the multivariable analysis, a lower expertise level of the biliary endoscopist (P = 0.037) and longer total procedure time (P = 0.026) were significant risk factor of PEP in patients who received conventional cannulation with sphincterotomy but only total procedure time (P = 0.004) was significant risk factor of PEP in those who received NKF. CONCLUSION Primary NKF was effective and safe in patients with prominent and bulging ampulla, even when performed by less-experienced endoscopist. We need to confirm which level of endoscopist's experience is needed for primary NKF through prospective randomized study.