1. Department of Neurosurgery, Tangdu Hospital, the Fourth Military Medical University, Xi’an;
2. Shaanxi Clinical Research Center for Neurosurgical Diseases, Xi’an, China
3. Department of Neurosurgery, the 987 Hospital of PLA Joint Logistic Support Force, Baoji;
4. Department of Health Statistics, the Fourth Military Medical University, Xi’an, China;
5. Department of Neurosurgery, Ankang Central Hospital, Ankang;
6. Department of Neurosurgery, Nuclear Industry 215 Hospital of Shaanxi Province, Xianyang; and