1. Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of The Ryukyus, Nishihara, Okinawa 903‑0215, Japan
2. Department of Otorhinolaryngology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa 903‑0215, Japan
3. Plastic and Reconstructive Surgery, Graduate School of Medicine, University of The Ryukyus, Nishihara, Okinawa 903‑0215, Japan