1 Center for Musculoskeletal Surgery Berlin Mitte; Charité University Medicine Berlin, Charitéplatz 1, Berlin 10117, Germany. Electronic address: tu-lan.vu-han@charite.de.
2 Center for chronically sick children, Department of Neuropediatrics; Charité University, Medicine Berlin, Augustenburger Platz 1, Berlin 13353, Germany.
3 Center for Musculoskeletal Surgery Berlin Mitte; Charité University Medicine Berlin, Charitéplatz 1, Berlin 10117, Germany.