1. Department of Otolaryngology, Himeji Red Cross Hospital, Himeji City, Japan;
2. Department of Otolaryngology Head and Neck Surgery, Kumamoto University Graduate School of Medicine, Kumamoto City, Japan;
3. Otolaryngology, Nakada ENT Clinic, Himeji City, Japan;
4. Pathology, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan;
5. Department of Otolaryngology Head and Neck Surgery, Okayama University Graduate School of Medicine, Okayama, Japan