[Study about the healing of anastomoses in the irradiated colon--experimentation on animals (author's transl)].

Operations on preirradiated intestinal segments are followed by a high rate of complication. In order to determine the period after which an anastomosis on the clinically/therapeutically irradiated colon involves the greatest risk, 230 rats were submitted to a fractionated X-ray stationary-field irradiation of the colon with 50 Gy. The colon was anastomosed one day, four weeks, eight weeks, and four months respectively after the irradiation. A possible protective influence of fibrin on the healing of anastomoses was examined. The resistance to bursting pressure is taken as a criterion of the security of the anastomosis. It was determined on the third, 7th, 14th, and 21st day after the operation. The irradiation alone produces a markedly higher resistance to bursting pressure in the not operated control animals. After presurgical irradiation, the healing of anastomoses is delayed. There is no dependence on the period of time between irradiation and operation. From the 14th day after surgery, the resistance to bursting pressure is considerably higher than initially. In our experiment, the healing of anastomoses was not improved by an additional fibrin application.