1. Department of Otorhinolaryngology, Tokyo Medical University Hachioji Medical Center, Hachioji, Japan;
2. Department of Otorhinolaryngology, Tokyo Medical University, Shinjuku-ku, Japan;
3. Department of Otorhinolaryngology, Kosei Chuo General Hospital, Meguro-ku, Japan;
4. Tokyo Medical University, Brain Surgery, Shinjuku-ku, Japan