Inclusion Criteria:  patients aged >16 y undergoing elective or emergency colorectal surgery for cancer patients aged >16 y undergoing elective or emergency colorectal surgery for diverticular disease patients aged >16 y undergoing elective or emergency colorectal surgery for inflammatory bowel-disease patients aged >16 y undergoing elective or emergency colorectal surgery for reversal of Hartmann's procedure.  Exclusion Criteria:  patients aged < 16 y undergoing colorectal surgery; patients undergoing Hartman's procedure