1. Department of Hepatobiliary Surgery, Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
2. Department of General Surgery, The Second People's Hospital of Liaocheng, Liaocheng, Shandong 252600, P.R. China
3. Department of Emergency, The Second People's Hospital of Liaocheng, Liaocheng, Shandong 252600, P.R. China