1. Department of Otorhinolaryngology, Head and Neck Surgery, St. Johannes Hospital, Cath. St. Paulus Society, Academic Teaching Hospital of the University of Münster, Johannesstr. 9-17, 44137 Dortmund, Germany
2. Department of Otorhinolaryngology, Head and Neck Surgery, Katholisches Klinikum, Ruhr University Bochum, Bleichstr. 15, 44787 Bochum, Germany