[1] Univ Utrecht, Med Ctr, Dept Surg, NL-3508 GA Utrecht, Netherlands
[2] Univ Utrecht, Med Ctr, Dept Gastroenterol, NL-3508 GA Utrecht, Netherlands
[3] Univ Utrecht, Med Ctr, Dept Clin Epidemiol, NL-3508 GA Utrecht, Netherlands
[4] Univ Amsterdam, Acad Med Ctr, Dept Surg, NL-1105 AZ Amsterdam, Netherlands
[5] Univ Amsterdam, Acad Med Ctr, Dept Gastroenterol, NL-1105 AZ Amsterdam, Netherlands
[6] Free Univ Amsterdam, Acad Hosp, Dept Surg, Amsterdam, Netherlands
[7] Free Univ Amsterdam, Acad Hosp, Dept Gastroenterol, Amsterdam, Netherlands
[8] Antonius Hosp, Dept Surg, Nieuwegein, Netherlands
[9] Antonius Hosp, Dept Gastroenterol, Nieuwegein, Netherlands
[10] Erasmus Hosp, Dept Surg, Rotterdam, Netherlands