Seung-No Hong1,2, Seung Hoon Lee2, Jeong-Whun Kim3. 1. Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 173 Goomi-ro, Bundang-gu, Seongnam, 463-707, South Korea. 2. Department of Otorhinolaryngology, Korea University College of Medicine, Korea University Ansan Hospital, Ansan, South Korea. 3. Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 173 Goomi-ro, Bundang-gu, Seongnam, 463-707, South Korea. kimemails7@gmail.com.