1 Department of Otorhinolaryngology-Head and Neck Surgery, Chuncheon Sacred Heart Hospital and Institute of New Frontier Research, Hallym University College of Medicine, Chuncheon, Korea. doctordk@naver.com.
2 Department of Otorhinolaryngology-Head and Neck Surgery, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.