[1] Kitasato Univ Med Ctr, Dept Otorhinolaryngol, Kitamoto, Japan
[2] Kitasato Univ, Dept Otorhinolaryngol Head & Neck Surg, Sch Med, Sagamihara, Japan
[3] Natl Def Med Coll, Dept Otorhinolaryngol, Tokorozawa, Japan
[4] Kitasato Univ, Sch Allied Hlth Sci, Sagamihara, Japan