Abstract:Objective To evaluate the value of endoclip-assisted and submucosal injection-assisted cannulation techniques for difficult cannulation during endoscopic retrograde cholangiopancreatography (ERCP). Methods Data of 12 458 patients treated with ERCP for the first time in the First Affilated Hospital of Naval Medical University from June 2015 to September 2020 were retrospectively analyzed. Twenty eight (0.22%) were identified as difficult cannulation where metal clip- or submucosal injection-assisted cannulation was used. The selective cannulation success rate, intubation time and complication incidence of the two techniques in difficult cannulation patients were analyzed. Results Difficult cannulation was performed in 18 males (64.3%) and 10 females (35.7%) with an age of 69.6±14.1 years assisted by metal clips or submucosal injection. Five cases (17.9%) were type Ⅱ, 5 cases (17.9%) type Ⅲ, and 18 cases (64.3%) type Ⅴ according to papilla classification. Sixteen patients (57.1%) received metal clip-assisted cannulation, and 12 cases (42.9%) submucosal injection-assisted cannulation. Twenty-five (89.3%) patients successfully underwent selective cannulation with the cannulation time of 9.9±4.3 min. One case (3.6%) of mild post-ERCP pancreatitis and 3 cases (10.7%) of post-ERCP hyperamylasemia occurred. No postoperative bleeding or perforation occurred. All patients were cured and discharged after conservative treatment. Conclusion When selective cannulation is difficult due to poor papilla exposure or deflection, endoclip- or submucosal injection-assisted cannulation can effectively improve the successful selective cannulation rate during ERCP with low complication incidence, which is worth of clinical promotion.