1. Department of Otorhinolaryngology–Head and Neck Surgery, ROK Armed Forced Capital Hospital, Bundang, Korea;
2. Hana ENT Hospital, Seoul, Korea;
3. Center for Clinical Epidemiology, Samsung Medical Center, Seoul, Korea;
4. Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea;
5. Department of Otorhinolaryngology–Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea