1. Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
2. Department of Otorhinolaryngology Head and Neck Surgery, Osaka University Graduate School of Medicine, Yamadaoka, Suita City, Osaka, Japan
3. Department of Otolaryngology, Nara Medical University, Shijocho, Kashihara City, Nara, Japan
4. Department of Otolaryngology, Osaka General Medical Center, Mandai-higashi, Sumiyoshi-ku, Osaka City, Osaka, Japan