1. Department of Otorhinolaryngology; Mayo Clinic School of Medicine; Rochester Minnesota
2. Department of Neurologic Surgery; Mayo Clinic School of Medicine; Rochester Minnesota
3. Division of Health Care Policy and Research and the Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery; Mayo Clinic School of Medicine; Rochester Minnesota
4. Bobby R. Alford Department of Otolaryngology-Head and Neck Surgery; Baylor College of Medicine; Houston Texas
5. Department of Otolaryngology-Head and Neck Surgery; Vanderbilt University; Nashville Tennessee U.S.A