1. Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
2. Department of Neurosurgery, Henan Provincial People's Hospital, Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
3. Department of Neurosurgery, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong 264000, P.R. China
4. Department of Neurosurgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
5. Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, P.R. China