1. Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, Vein Center of the Departments of Dermatology and Vascular Surgery Bochum, Germany
2. Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, Vein Center of the Departments of Dermatology and Vascular Surgery Bochum, Germany, and Competence Centre for Phlebology and Dermatology, Artemed-Fachklinik Prof. Dr. Dr. Salfeld GmbH & Co. KG, Bad Oeynhausen, Germany