[1] Brown Univ, Warren Alpert Med Sch, Providence, RI 02912 USA
[2] Univ Pittsburgh, Sch Med, Pittsburgh, PA 15213 USA
[3] Univ Pittsburgh, Med Ctr, Dept Otolaryngol Head & Neck Surg, Pittsburgh, PA 15213 USA
[4] Tufts Univ, Med Ctr, Dept Otolaryngol Head & Neck Surg, Boston, MA 02111 USA
[5] Rhode Isl Hosp, Hasbro Childrens Hosp, Div Otolaryngol Head & Neck Surg, Providence, RI USA
[6] Univ Calif San Francisco, Dept Otolaryngol Head & Neck Surg, San Francisco, CA USA