1. Department of Surgery , 30857 Bürgerspital Solothurn , CH-4500 Solothurn , Switzerland
2. Department of Surgery, University Hospital Zürich , University of Zürich , Zürich , Switzerland
3. Jungfraupraxis Interlaken , Interlaken , Switzerland
4. Department of Vascular Surgery, University Hospital Bern , University of Bern , Bern , Switzerland