[1] Lanzhou Univ, Sch Clin Med 1, Dept Gen Surg, Lanzhou 730000, Peoples R China
[2] Lanzhou Univ, Hosp 1, Dept Gen Surg, Lanzhou, Peoples R China
[3] Lanzhou Univ, Clin Med Sch 2, Dept Gen Surg, Lanzhou, Peoples R China
[4] Lanzhou Univ, Hosp 2, Dept Gen Surg, 80,Cuiyingmen, Lanzhou 73000, Peoples R China
[5] Lanzhou Univ, Clin Med Sch, 80,Cuiyingmen, Lanzhou 73000, Peoples R China