1. Department of Pediatric Surgery, Olga Hospital, Klinikum Stuttgart, Stuttgart, Germany
2. Department of Pediatric Radiology, Olga Hospital, Klinikum Stuttgart, Stuttgart, Germany
3. Department of Neonatology, University Children's Hospital Tübingen, Tübingen, Germany
4. Department of Medical Statistics and Biomathematics, Medical Faculty of Mannheim, Mannheim, Germany
5. Department of Pediatric Surgery, University Hospital of Mannheim, Mannheim, Germany