Anastomotic leaks after colorectal anastomosis occurring more than 30 days postoperatively: a single-institution evaluation.

National hospital registries only report colorectal anastomotic leaks (ALs) within 30 days postoperatively. The aim of our study was to determine the incidence and significance of ALs that occur beyond 30 days postoperatively. We performed a retrospective review of our prospective database from June 2008 to August 2012. A total of 504 patients were included. These patients were operated on by two surgeons. Any clinical or radiographic abnormalities were considered to be an anastomotic imperfection. A total of 504 patients were reviewed with a total of 18 (3.6%) anastomotic leaks. Six leaks (31.6% of leaks) were diagnosed more than 30 days postoperatively (P < 0.001). Of the 18 leaks, interventional radiology drainage was performed for four cases and 14 patients required reoperation. All six delayed leaks required reoperation. There was one leak that occurred under 30 days, which was discovered on autopsy. The median follow-up was 12 months (range, 1 to 4 months). All the delayed leak patients presented with fistulas, whereas 58 per cent of typical leak patients presented with the triad of leukocytosis, fever, and abdominal pain. Colorectal anastomotic leaks can occur after the 30-day postoperative period. In patients with vague and atypical abdominal findings, anastomotic leak must be suspected. More systematic, prospective studies are required to help us further understand the risk factors and natural history of anastomotic failures in elective colorectal surgery.