1. Division of Otolaryngology Head and Neck Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada B3J 3G9
2. Division of Pediatric Otolaryngology, University of California-San Diego, San Diego, CA 92123, USA
3. Division of Pediatric Pathology, University of California-San Diego, San Diego, CA 92123, USA
4. Department of Otolaryngology, IWK Health Centre, 5850/5980 University Avenue, P.O. Box 9700, Halifax, NS, Canada B3K 6R8