Jörg Kleeff1, Christoph W Michalski2. 1. Department of Visceral, Vascular and Endocrine Surgery, Martin-Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany. Electronic address: joerg.kleeff@uk-halle.de. 2. Department of Visceral, Vascular and Endocrine Surgery, Martin-Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany.