[1] Chifeng Univ, Dept Neurosurg, Affiliated Hosp, Chifeng, Peoples R China
[2] Chifeng Univ, Hlth Sci Ctr, Coll Basic Med, Dept Anat, Chifeng, Peoples R China
[3] Chifeng Univ, Dept Oral & Maxillofacial Surg, Affiliated Hosp, Chifeng, Peoples R China
[4] Tianjin Med Univ Canc Inst & Hosp, Natl Clin Res Ctr Canc, Tianjins Clin Res Ctr Canc, Dept Pancreat Canc,Key Lab Canc Prevent & Therapy, Tianjin 300060, Peoples R China