1. Department of Biliary-Hepatic Surgery, The Affiliated Tumor Hospital of Guizhou Medical University, Guiyang, Guizhou 550000, P.R China
2. Department of Biliary-Hepatic Surgery, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550000, P.R China
3. Department of Biliary-Hepatic Surgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou 550025, P.R China