1. Department of Surgery and Otolaryngology, School of Medicine, University of California, San Diego, La Jolla, California, USA
2. Department of Otorhinolaryngology-Head and Neck Surgery, Gyeongsang National University School of Medicine, Gyeongsang National University Changwon Hospital, Changwon, South Korea
3. Research Service, Veterans Administration Medical Center, San Diego, California, USA
4. Department of Otorhinolaryngology, Gangneung Asan Hospital, Gangneung, South Korea