Effects of low-dose preoperative irradiation on low anterior anastomosis in dogs.

Twenty mongrel dogs underwent preoperative radiation therapy to the colon and rectum using the Nominal Standard Dose Equation to simulate treatment with 2000 rads. Each dog then underwent anterior resection of the rectosigmoid, and reconstruction was randomized into two groups consisting of either handsewn or EEA-stapled anastomoses. Anastomoses were examined digitally and radiographically on the day of surgery and on the seventh postoperative day. There were three radiographic leaks among the ten dogs having the handsewn anastomoses and one radiographic leak among the ten dogs having the EEA-stapled anastomoses. There was one clinically significant leak which occurred in a dog having an EEA-stapled anastomosis and was associated with peritonitis and death. The overall leak rate was 30 per cent among dogs having handsewn anastomoses and 20 per cent among dogs with stapled anastomoses. The data suggest that an anterior resection in low colorectal anastomosis can be done safely after low-dose radiation using either handsewn or stapling techniques.