1 Division of ENT Diseases, CLINTEC, Karolinska Institutet, Stockholm, Sweden.
2 Department of Otorhinolaryngology, Lund University, Skåne University Hospital, Malmö, Sweden.
3 Department of Otorhinolaryngology, Lund University, Skåne University Hospital, Malmö, Sweden; Department of ENT Diseases, Karolinska University Hospital, Stockholm, Sweden. Electronic address: lars-olaf.cardell@ki.se.