1. Department of Surgery, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
2. Department of Hepatobiliary Surgery, Taixing People's Hospital, The Affiliated Taixing People's Hospital of Yangzhou University, Taixing, Jiangsu 225400, P.R. China
3. Department of Hepatobiliary Surgery, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, Jiangsu 225300, P.R. China