1. Department of Paediatric Surgery, University Hospital of Rostock, Ernst-Heydemann, Rostock, Germany
2. Klinikum der Johann Wolfgang-Goethe Universität Frankfurt/M. - Klinik für Kinderchirurgie, Frankfurt, Germany
3. Department of Paediatric Surgery, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, Oxfordshire, United Kingdom