i. Exposures and their measurement: The exposure is the treatment strategy. The intervention being evaluated is loop ileostomy with intra-operative colonic lavage. Ileostomy and colonic lavage is not considered standard of care at our institutions. Patients managed with ileostomy and colonic lavage who do not respond as expected may be converted to TAC, intra- or post-operatively, at the discretion of the surgeon. These patients will be analyzed in the ileostomy group (similar to an intention to treat analysis) since this was the original treatment strategy assigned. A subgroup analysis of these patients who had to be converted to TAC, and their impact on the overall results, will also be examined.