1. Department of Otorhinolaryngology-Head and Neck Surgery, Kyung Hee University School of Medicine, Seoul, Korea.
2. Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
3. Department of Otorhinolaryngology-Head and Neck Surgery, Hallym University College of Medicine, Hwaseong, Korea.