Affiliation: | 1. Department of Otolaryngology, University of Pittsburgh Medical Center, , Pittsburgh, Pennsylvania, U.S.A;2. University of Pittsburgh College of Medicine, , Pittsburgh, Pennsylvania, U.S.A;3. Department of Pediatric Otolaryngology, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, , Pittsburgh, Pennsylvania, U.S.A;4. Department of Pediatrics, Division of Pediatric Pulmonology, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, , Pittsburgh, Pennsylvania, U.S.A |