Affiliation: | 1.Department of Otolaryngology-Head and Neck Surgery, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, South Korea ;2.Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Chungnam National University, Daejeon, South Korea ;3.Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Kyung Hee University, Seoul, South Korea ;4.Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Seoul National University, Seoul, South Korea ;5.Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Konkuk University, Seoul, South Korea ;6.Department of Otolaryngology-Head and Neck Surgery, School of Medicine, College of Medicine, Dankook University, Cheonan, South Korea ;7.Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Korea University, Seoul, South Korea ;8.Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Pusan National University, Busan, South Korea ;9.Department of Medical Statistics, School of Medicine, Catholic University of Daegu, Gyeongsan, South Korea ;10.Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Catholic University of Daegu, Daegu, South Korea ;11.Department of Otorhinolaryngology, Daegu Catholic University Medical Center, 33 Duryugongwon-ro 17-gil, Nam-Gu, Daegu, 705-718, South Korea ; |