1. c/o University of Ulm; Ulm Germany
2. Center of Oncologic, Endocrine and Minimal Invasive Surgery; Donau-Klinikum; Neu-Ulm Germany
3. Department of Surgery; Peking University First Hospital; P.R. of China
4. Department of General and Visceral Surgery; St. Josef-Hospital Bochum, Ruhr-University; Germany