Yudong Liu1,2, Baoshan Wang3. 1. Department of Otorhinolaryngology, The Second Hospital of Hebei Medical University, No. 215 West Heping Road, Shijiazhuang, 050000, People's Republic of China. 2. Department of Otorhinolaryngology, Hebei General Hospital, Shijiazhuang, 050051, People's Republic of China. 3. Department of Otorhinolaryngology, The Second Hospital of Hebei Medical University, No. 215 West Heping Road, Shijiazhuang, 050000, People's Republic of China. hebwangbs@163.com.