1. Department of Otorhinolaryngology, Head and Neck Surgery, Keio University, School of Medicine, Tokyo 160-8582, Japan
2. Department of Otorhinolaryngology, Head and Neck Surgery, Kyushu University, School of Medicine, Fukuoka 812-0054, Japan
3. Department of Otorhinolaryngology, Kamio Memorial Hospital, Tokyo 101-0063, Japan
4. Collaborative Research Resources, Core Instrumentation Facility, Keio University, Tokyo 160-8582, Japan
5. Department of Otorhinolaryngology-Head and Neck Surgery, Nihon University, School of Medicine, Tokyo 173-8610, Japan