[1] Mayo Clin, Dept Otorhinolaryngol Head & Neck Surg, Rochester, MN USA
[2] Mayo Clin, Div Hlth Care Policy & Res, Sch Med, Rochester, MN USA
[3] Mayo Clin, Robert D & Patricia E Kern Ctr Sci Hlth Care Deliv, Sch Med, Rochester, MN USA
[4] Mayo Clin, Dept Otorhinolaryngol Head & Neck Surg, 200 First St SW, Rochester, MN 55905 USA