1. Department of Otolaryngology, Japanese Red Cross Shizuoka Hospital, Shizuoka, Japan
2. Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, Tokyo, Japan
3. Department of Otolaryngology, Saiseikai Utsunomiya Hospital, Tochigi, Japan
4. Department of Otolaryngology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan