1. Department of Otorhinolaryngology-Head and Neck Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan
2. Department of Otorhinolaryngology, Head and Neck Surgery, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
3. Department of Surgery, School of Medicine, Toho University Omori Medical Center, Tokyo, Japan