1. Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery; Uppsala University; Uppsala Sweden
2. Department of Surgical Sciences, Plastic and Maxillofacial Surgery; Uppsala University; Uppsala Sweden
3. Department of Plastic and Reconstructive Surgery and the Institute for Surgical Research; Oslo University Hospital Rikshospitalet; Oslo Norway
4. Department of Otorhinolaryngology; Karolinska University Hospital; Stockholm Sweden
5. Uppsala Clinical Research Centre; Uppsala Sweden