1. Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
2. Department of Otorhinolaryngology, Abe ENT Clinic, Ota‐ku, Japan
3. Department of Otorhinolaryngology, Jikei University School of Medicine, Minato‐ku, Tokyo, Japan
4. Department of Otorhinolaryngology, University of Miyazaki Faculty of Medicine, Miyazaki, Japan