1. Department of Otorhinolaryngology, National Health Insurance Service Ilsan Hospital, Goyang, Korea
2. Department of Otorhinolaryngology, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
3. Department of Otorhinolaryngology-Head and Neck Surgery, Dongtan Sacred Heart Hospital, Hallym University College of Medicine, Hwaseong, Korea