1. Department of Otorhinolaryngology–Head and Neck SurgeryKorea University College of MedicineKorea University Ansan Hospital Ansan South Korea
2. Department of Neurosurgery, Samsung Medical CenterSungkyunkwan University School of Medicine Seoul South Korea
3. Department of Otorhinolaryngology–Head and Neck SurgerySamsung Medical CenterSungkyunkwan University School of Medicine Seoul South Korea