1. Department of Otorhinolaryngology-Head and Neck Surgery; Soonchunhyang University College of Medicine, Seoul Hospital; Seoul Korea
2. Department of Otorhinolaryngology-Head and Neck Surgery; Soonchunhyang University College of Medicine, Bucheon Hospital; Bucheon Korea
3. Department of Otorhinolaryngology-Head and Neck Surgery; Soonchunhyang University College of Medicine, Cheonan Hospital; Cheonan Korea