1. Department of Otorhinolaryngology–Head and Neck Surgery, University Medicine Mannheim, University of Heidelberg, Mannheim, Germany
2. Department of Otorhinolaryngology–Head and Neck Surgery, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
3. Institute for Evidence in Medicine (for Cochrane Germany Foundation), Medical Center–University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany