1. Department of Vascular Surgery, St. Josef Hospital Bochum, Katholisches Klinikum Bochum, Ruhr University Bochum, Germany
2. Vein Centre of the Departments of Dermatology and Vascular Surgery, Katholisches Klinikum Bochum, Germany
3. Department of Dermatology, St. Josef Hospital Bochum, Katholisches Klinikum Bochum, Ruhr University Bochum, Germany