1. Fourth Department of General Surgery, Hebei General Hospital, Shijiazhuang, Hebei 050051, P.R. China
2. Outpatient Department, Hebei General Hospital, Shijiazhuang, Hebei 050051, P.R. China
3. Third Department of General Surgery, Hebei General Hospital, Shijiazhuang, Hebei 050051, P.R. China