1. Department of Otolaryngology–Head and Neck Surgery University of Texas Southwestern Medical Center Dallas Texas U.S.A.
2. Division of Pediatric Otolaryngology Children's Health Dallas Dallas Texas U.S.A.
3. Department of Otolaryngology–Head and Neck Surgery Northwestern University Feinberg School of Medicine Chicago Illinois U.S.A.
4. Division of Pediatric Otolaryngology Ann & Robert H. Lurie Children's Hospital of Chicago Chicago Illinois U.S.A.
5. Department of Otolaryngology–Head and Neck Surgery University of Cincinnati Cincinnati Ohio U.S.A.