1. Department of Head & Neck Surgery, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
2. Department of Otolaryngology, Head & Neck Surgery, Eastern Virginia Medical School, Norfolk, Virginia, USA
3. Upper Airways Research Laboratory, Department of Otorhinolaryngology–Head and Neck Surgery, University of Ghent, Ghent, Belgium
4. Department of Otorhinolaryngology, Amsterdam University Medical Centres, location AMC, Amsterdam, The Netherlands
5. Department of Otorhinolaryngology–Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium
6. Guy’s and St. Thomas’ NHS Foundation Trust, London, UK
7. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
8. Department of Otorhinolaryngology, Hospital Clínic Universitari, Barcelona, Spain