1. Department of Otorhinolaryngology, Head and Neck Surgery, Ruhr University Bochum, St. Elisabeth Hospital Bochum
2. Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, and University of Zurich, Zurich, Switzerland
3. Institute of Neuroradiology, Ruhr University Bochum, St. Josef Hospital Bochum