1. Department of Otolaryngology, Unfallkrankenhaus Berlin, University of Berlin, 12683 Berlin, Germany
2. Department of Otolaryngology, University Hospital Lucus Augusti, 27003 Lugo, Spain
3. Center for Otolaryngology, 47829 Krefeld, Germany
4. Department of Otolaryngology, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo 01246-903, Brazil
5. Department of Otolaryngology, Pontifícia Universidade Católica de Campinas, Campinas 13034-685, Brazil
6. Department of Otolaryngology, Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain