1. Department of Neurosurgery The First Hospital of Jilin University, Changchun, Jilin 130000, P.R. China
2. Department of Pathology, The First Hospital of Jilin University, Changchun, Jilin 130000, P.R. China
3. Department of Neurosurgery, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China