Diverting ileostomy in colorectal surgery: when is it necessary?

PURPOSE: The role of fecal diversion using a loop ileostomy in patients undergoing rectal resection and anastomosis is controversial. There has been conflicting evidence on the perceived benefit vs. the morbidity of a defunctioning stoma. This is a review of the relevant surgical literature evaluating the risks, benefits, and costs of constructing a diverting ileostomy in current colorectal surgical practice.
METHODS: Retrospective and prospective articles spanning the past 50 years were reviewed to identify the definition of an anastomotic leak (AL), evaluate risk factors for AL, and assess methods of evaluation of the anastomosis. We then pooled the evidence for and against fecal diversion, the incidence and consequences of stomal complications, and the evidence comparing loop ileostomy vs. loop colostomy as the optimal method of fecal diversion.
RESULTS: Evidence shows that despite the fact that fecal diversion does not decrease postoperative mortality, it does significantly decrease the risk of anastomotic leak and the need for urgent reoperation when a leak does occur. Diverting stomas are a low-risk surgical procedure from a technical standpoint but carry substantial postoperative morbidity that can greatly hamper patients' quality of life and recovery. High-risk patients such as those with low colorectal anastomoses (<10 cm from anal verge), colo-anal anastomoses, technically difficult resections, malnutrition, and male patients seem to reap the greatest benefit from fecal diversion.
CONCLUSIONS: Fecal diversion is recommended as a selective tool to protect or ameliorate an anastomotic leak after a colorectal anastomosis. It is most beneficial when used selectively in high-risk patients with low pelvic anastomoses that are at an increased risk for AL. New tools are needed to identify patients at high risk for anastomotic failure after anterior resection.