A defunctioning ileostomy does not prevent clinical anastomotic leak after a low anterior resection: a prospective, comparative study.

PURPOSE: Defunctioning ileostomy or colostomy is still routinely performed after low anterior resection in the belief that diverting the fecal stream will prevent anastomotic dehiscence. However, an ileostomy is not without morbidity for the patient. This study aims to determine if a diverting stoma is really necessary after a low anastomosis.

METHODS: All low or ultralow anterior resections done in this department were performed by consultant-grade surgeons in a standardized manner. The patients were all monitored closely after surgery for clinical signs of an anastomotic leak. There were 1078 patients who underwent elective low or ultralow anterior resections in a ten-year period between 1994 and 2004. Twelve of them were irradiated before surgery; they were excluded from the study. During a seven-month period from February 2004 through August 2004, 324 patients who underwent such procedures were not defunctioned. These were compared with 742 patients who were previously defunctioned with a proximal stoma. The results were analyzed using the Pearson chi-squared test.

RESULTS: Thirteen (4 percent) patients who were not defunctioned developed a clinical anastomotic leak, whereas the leak rate for those who were defunctioned was 3.8 percent. There was no statistical difference demonstrated. Ninety-five percent of patients who developed a leak required surgical intervention; the remaining 5 percent could be dealt with by radiologic drainage. The overall mortality rate for anastomotic leak in this department is 7.3 percent.

CONCLUSION: A diverting stoma does not reduce postoperative anastomotic leak rate. Rather, it reduces the otherwise catastrophic effects of an anastomotic leak such as fecal peritonitis and septicemia. An ileostomy carries certain morbidity and also adds to the cost of the entire operation. Therefore, it should not be performed routinely. Instead, it should be performed selectively in patients with poorly prepared bowels, coupled with a distal limb washout, and in patients with significant comorbidities who can ill afford the complications of a leak.