[1] Erasmus MC, Dept Surg Rotterdam, Rotterdam, Netherlands
[2] Maasstad Hosp, Dept Surg, Rotterdam, Netherlands
[3] Erasmus MC, Dept Biostat, Rotterdam, Netherlands
[4] Hosp St Franciscus Gasthuis, Dept Surg, Rotterdam, Netherlands
[5] Ikazia Hosp, Dept Surg, Rotterdam, Netherlands