1. Department of Otorhinolaryngology–Head and Neck Surgery, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Gyeonggi-do, Republic of Korea
2. Department of Otorhinolaryngology–Head and Neck Surgery, Korea University Ansan Hospital, Ansan, Gyeonggi-do, Republic of Korea
3. Department of Otorhinolaryngology–Head and Neck Surgery, Korea University Guro Hospital, Seoul, Republic of Korea
4. Department of Otorhinolaryngology–Head and Neck Surgery, Korea University Anam Hospital, Seoul, Republic of Korea