1. Department of Vascular Surgery, St. Josef Hospital Bochum, Clinic of the Ruhr University Bochum, Germany
2. Vein Center of the Departments of Dermatology and Vascular Surgery, Katholisches Klinikum Bochum, Germany
3. Department of Dermatology, St. Josef Hospital Bochum, Clinic of the Ruhr University Bochum, Germany
4. Institute of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Austria