1. Department of Neurosurgery, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi, P.R. China
2. Department of Geriatrics, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi, P.R. China
3. Department of Neurosurgery, Lvliang People's Hospital, Lvliang 033000, Shanxi, P.R. China