1. Department of Oto-Rhino-Laryngology, West China Hospital, West China Medical School, Sichuan University, Chengdu, China
2. Department of Epidemiology and Health Statistics, West China School of Public Health, Sichuan University, Chengdu, China
3. Department of Neurosurgery, West China Hospital, West China Medical School, Sichuan University, Chengdu, China