1 Department of Otorhinolaryngology-Head and Neck Surgery, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwon, 220-701, Republic of Korea.
2 Department of Otorhinolaryngology-Head and Neck Surgery, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, Gangwon, 220-701, Republic of Korea. rhico@yonsei.ac.kr.