1. Department of Otolaryngology – Head and Neck Surgery, Kobe City Medical Center General Hospital, Kobe, Japan;
2. Department of Otolaryngology – Head and Neck Surgery, Kurashiki Central Hospital, Kurashiki, Japan;
3. Department of Otolaryngology – Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan;
4. Department of Otolaryngology – Head and Neck Surgery, Japanese Red Cross Osaka Hospital, Osaka, Japan;
5. Department of Otolaryngology, Tenri Hospital, Tenri, Japan;
6. Department of Otolaryngology – Head and Neck Surgery, National Hospital Organization Kyoto Medical Center, Kyoto, Japan;
7. Department of Otolaryngology – Head and Neck Surgery, Kitano Hospital Tazuke Medical Research Institute, Osaka, Japan;
8. Department of Otolaryngology, Japanese Red Cross Otsu Hospital, Otsu, Japan;
9. Department of Otorhinolaryngology – Head and Neck Surgery, Shizuoka General Hospital, Shizuoka, Japan;
10. Department of Otolaryngology – Head and Neck Surgery, Kokura Memorial Hospital, Kokura, Japan;
11. Department of Otolaryngology, Japanese Red Cross Society Wakayama Medical Center, Wakayama, Japan