Department of Special Minimally Invasive Surgery;
The First Hospital of Lanzhou University;
Lanzhou 730000;
Gansu Province;
China;
Key Laboratory of Biological Therapy and Regenerative Medicine Transformation of Gansu Province;
The First Hospital of Lanzhou University;
Lanzhou 730000;
Gansu Province;
China;
Hepatopancreatobiliary Surgery Institute of Gansu Province;
Lanzhou 730000;
Gansu Province;
China;
The First Clinical Medical School of Lanzhou University;
Lanzhou 730000;
Gansu Province;
China;
The Second Department of General Surgery;
The First Hospital of Lanzhou University;
Lanzhou 730000;
Gansu Province;
China;
Cardiovascular Division;
Brigham and Women's Hospital;
Harvard Medical School;
Boston;
MA 02451;
United States;
The Fifth Department of General Surgery;
The First Hospital of Lanzhou University;
Lanzhou 730000;
Gansu Province;
China;
Department of Gastroenterology;
Kyoto Second Red Cross Hospital;
Kyoto 602-8026;
Japan;
Endoscopic retrograde cholangiopancreatography; Periampullary diverticulum; Classification; Difficult cannulation; Successful cannulation;