1. Department of Vascular Surgery, St. Josef Hospital Bochum, Katholisches Klinikum Bochum Department of the Ruhr University Bochum, Bochum, Germany
2. Vein Centre of the Departments of Dermatology and Vascular Surgery, Katholisches Klinikum Bochum, Bochum, Germany
3. Institute for Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Austria
4. Vein Centre Capio Bad Bertrich GmbH, Bad Bertrich, Germany
5. Department of Vascular Surgery, Krankenhaus Bethanien Moers, Germany
6. Vein Centre Capio Clinic im Park, Hilden, Germany
7. Gemeinschaftspraxis Saarlouis, Saarlouis, Germany
8. Department of Dermatology, St. Josef Hospital Bochum, Katholisches Klinikum Bochum, Department of the Ruhr University Bochum, Bochum, Germany