1 Department of Otolaryngology, Niigata Prefectural Shibata Hospital, Niigata, Japan; Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan.
2 Department of Otolaryngology, Niigata Prefectural Shibata Hospital, Niigata, Japan; Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan. Electronic address: takeshi-takahashi@med.niigata-u.ac.jp.
3 Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan.