[1] Univ Digest Hlth Care Ctr, St Clara Hosp, Clarunis, Basel, Switzerland
[2] Univ Hosp Basel, Basel, Switzerland
[3] Univ Basel, Basel, Switzerland
[4] Univ Washington, Dept Pediat, Sch Med, Seattle, WA USA
[5] Univ Hosp Basel, Univ Ctr Gastrointestinal & Liver Dis, Dept Visceral Surg, Clarunis, Spitalstr 21, CH-4031 Basel, Switzerland