1. Department of Neurosurgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250021, P.R. China
2. Department of Medical Records, Affiliated Hospital of Taishan Medical University, Taishan Medical University, Tai'an, Shandong 271000, P.R. China
3. Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China
4. Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
5. Department of Neurosurgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, P.R. China