1. Department of Otolaryngology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
2. Department of Otolaryngology, The First People's Hospital of Qujing, Qujing, Yunnan 655000, P.R. China
3. Department of Otolaryngology, Affiliated Hospital of Dali University, Dali, Yunnan 671000, P.R. China