1. Department of General Surgery, Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
2. Department of Hepatobiliary Surgery, The People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021, P.R. China
3. Department of Hepatobiliary Surgery, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academy of Medical Science, Jinan, Shandong 250117, P.R. China