1. Department of Otolaryngology, Juntendo University Nerima Hospital, Tokyo, Japan
2. Department of Anesthesiology, Tokyo Medical and Dental University, Tokyo, Japan
3. Department of Otolaryngology, Kameda Medical Center, Kamogawa, Japan
4. Department of Otolaryngology, Juntendo University, Tokyo, Japan
5. Kurita Hospital, Kawasaki, Japan