1. Department of Otorhinolaryngology – Head and Neck Surgery, Helsinki University Hospital University of Helsinki Helsinki Finland
2. Department of Otorhinolaryngology – Head and Neck Surgery, Turku University Hospital University of Turku Turku Finland
3. Department of Otorhinolaryngology – Head and Neck Surgery, Tampere University Hospital University of Tampere Tampere Finland
4. Department of Otorhinolaryngology – Head and Neck Surgery, Kuopio University Hospital University of Eastern Finland Kuopio Finland
5. Department of Otorhinolaryngology – Head and Neck Surgery, Oulu University Hospital University of Oulu Oulu Finland
6. Department of Oral and Maxillofacial Surgery, Helsinki University Hospital University of Helsinki Helsinki Finland
7. Department of Clinical Sciences, Intervention and Technology, Division of Ear, Nose and Throat Diseases, Karolinska Institutet Karolinska University Hospital Stockholm Sweden
8. Faculty of Medicine, Research Program in Systems Oncology University of Helsinki Helsinki Finland