3 Clinic for Visceral, Tumour, Transplantation and Vascular Surgery, Medical Center Cologne-Merheim, Cologne, Germany.
4 Clinic for Plastic and Aesthetic Surgery, Medical Center Cologne-Merheim, Cologne, Germany.
5 Faculty for Health, University Witten/Herdecke, Witten, Germany.
6 Department of Paediatric Anaesthesiology and Endoscopy, Children's Hospital Cologne, Amsterdamer Straße 59, 50735, Cologne, Germany. [email protected].
7 Faculty for Health, University Witten/Herdecke, Witten, Germany. [email protected].