1. Department of Otorhinolaryngology, International University of Health and Welfare School of Medicine
2. Department of Otorhinolaryngology, Head and Neck Surgery, International University of Health and Welfare, Narita Hospital
3. Department of Otorhinolaryngology, International University of Health and Welfare, Mita Hospital
4. Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
5. Department of Otolaryngology-Head and Neck Surgery, Kagawa Prefectural Central Hospital
6. Department of Otolaryngology-Head and Neck Surgery, Kagawa Rosai Hospital