1. Department of OtolaryngologyKochi Health Sciences Center Kochi Japan
2. Department of Otolaryngology‐Head and Neck SurgeryKagawa Rosai Hospital Kagawa Japan
3. Department of Otolaryngology‐Head and Neck SurgeryOkayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Okayama Japan
4. Department of Head and Neck surgeryNational Hospital Organization Shikoku Cancer Center Ehime Japan
5. Department of Cardiovascular MedicineKagawa Rosai Hospital Kagawa Japan