1. Department for General, Visceral and Transplantation Surgery at the University Hospital of Tübingen, Workgroup for Experimental Endoscopy, Development and Training, Waldhörnlestrasse 22, 72072 Tübingen, Germany
2. Interdisciplinary Endoscopic Unit, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076 Tübingen, Germany