1. Department of Otorhinolaryngology-Head and Neck Surgery, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea.
2. Department of Otorhinolaryngology, Al Jabr Eye and ENT Hospital, Al Hufuf and Al Mubarraz, Saudi Arabia.
3. Department of Otorhinolaryngology-Head and Neck Surgery, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
4. Department of Otorhinolaryngology-Head and Neck Surgery, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.