1. Department of Otorhinolaryngology—Head and Neck Surgery Chungnam National University College of Medicine Daejeon South Korea
2. Department of Otorhinolaryngology, Ilsan Paik Hospital Inje University College of Medicine Ilsan South Korea
3. Department of Otorhinolaryngology Yonsei University College of Medicine Seoul South Korea
4. Department of Otorhinolaryngology—Head and Neck Surgery Sungkyunkwan University School of Medicine, Samsung Medical Center Seoul South Korea