1. Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
2. Department of Hospital Infection Management, Zhongning County People's Hospital, Zhongwei, Ningxia 751200, P.R. China
3. Ningxia Key Laboratory of Cerebro Cranial Disease, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
4. Department of Nursing, Wuxi Higher Health Vocational Technology School, Wuxi, Jiangsu 214028, P.R. China