1. Department of Otolaryngology-Head and Neck Surgery, Sano Kosei General Hospital
2. Department of Otorhinolaryngology, Saitama Red Cross Hospital
3. Department of Otorhinolaryngology, Yokohama Municipal Citizen's Hospital
4. Department of Otorhinolaryngology-Head and Neck Surgery, Keio University School of Medicine
5. Department of Otolaryngology, Nippon Koukan Hospital and Koukan Clinic
6. Department of Otolaryngology, Japanese Red Cross Shizuoka Hospital
7. Department of Otolaryngology, Saiseikai Utsunomiya Hospital