[1] Heidelberg Univ, Dept Gastroenterol, Heidelberg, Germany
[2] Heidelberg Univ, Dept Gen Surg, Heidelberg, Germany
[3] St Joseph Hosp Dortmund Horde, Dortmund, Germany
[4] Univ Amsterdam, Acad Med Ctr, Dept Gastroenterol & Hepatol, NL-1105 AZ Amsterdam, Netherlands