1 Department of Otolaryngology, Tohoku Rosai Hospital, 4-3-21 Dainohara, Aoba-ku, Sendai, Miyagi, 981-8563, Japan. kenw@orl.med.tohoku.ac.jp.
2 Department of Otolaryngology, Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan. kenw@orl.med.tohoku.ac.jp.
3 Department of Otolaryngology, Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan.