1 Department of Pediatric Surgery, Marien Hospital, St. Elisabeth Group, Ruhr-University of Bochum, Witten, Germany.
2 Department of Pediatric Surgery, Marien Hospital, St. Elisabeth Group, Ruhr-University of Bochum, Witten, Germany matthias.nissen@elisabethgruppe.de.
3 Department of Neonatology and Paediatric Intensive Care, Vest Children's Hospital Datteln, University of Witten Herdecke, Datteln, Germany.
4 Department of Pediatric Surgery, St. Johannes Hospital, Helios Group, Duisburg, Germany.