1. Department of Otorhinolaryngology , Head and Neck Surgery, , Yokohama
2. Yokohama City University, School of Medicine , Head and Neck Surgery, , Yokohama
3. Department of Otolaryngology , Head and Neck Surgery, , Toyoake
4. Fujita Health University , Head and Neck Surgery, , Toyoake
5. Department of Otorhinolaryngology , Head and Neck Surgery, , Kitakyushu
6. University of Occupational and Environmental Health , Head and Neck Surgery, , Kitakyushu
7. Department of Otolaryngology , Head and Neck Surgery, , Hiroshima
8. Hiroshima University , Head and Neck Surgery, , Hiroshima
9. Department of Otolaryngology , Head and Neck Surgery, , Kagawa
10. Kagawa University , Head and Neck Surgery, , Kagawa
11. Department of Otolaryngology , Head and Neck Surgery, , Nagakute
12. Aichi Medical University , Head and Neck Surgery, , Nagakute
13. Department of Otorhinolaryngology , Head and Neck Surgery, , Tokyo , Japan
14. Tokyo Medical University , Head and Neck Surgery, , Tokyo , Japan