1. Department of Head and Neck Surgery, Aichi Cancer Center Hospital, Chikusaku, Nagoya 464‑8681, Japan
2. Department of Maxillofacial Surgery, Aichi Gakuin University, Chikusaku, Nagoya 464‑8650, Japan
3. Department of Otorhinolaryngology, Toyohashi Municipal Hospital, Aotakecho, Toyohashi 441‑8570, Japan
4. Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, University of The Ryukyus, Nishiharacho, Okinawa 903‑0215, Japan