[1] Univ Med Ctr Hamburg Eppendorf, Dept Pediat Surg, Martinistr 52, D-20246 Hamburg, Germany
[2] Heidelberg Univ, Univ Med Ctr Mannheim, Dept Pediat Surg, Theodor Kutzer Ufer 1-3, D-68167 Mannheim, Germany
[3] Univ Med Ctr Hamburg Eppendorf, Dept Pediat Hematol & Oncol, Martinistr 52, D-20246 Hamburg, Germany
[4] Univ Med Ctr Hamburg Eppendorf, Dept Child & Adolescent Psychiat Psychosomat & Psy, Martinistr 52, D-20246 Hamburg, Germany