1. Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin 300000, P.R. China
2. Department of Neurosurgery, Third People's Hospital of Chengdu, Chengdu, Sichuan 610000, P.R. China
3. Department of Pathology, Tianjin Huanhu Hospital, Tianjin 300000, P.R. China