Temporary ischemia and healing of colonic anastomoses

The objective of the study was to assess the effect of a temporary ischemic condition, produced by a 20 minute vascular clamping of the marginal and caudal mesenteric arteries, on the healing process in end-to-end colonic anastomoses. Following the ischemic interval the colon was divided and anastomosed using 5-0 silk interrupted sutures. Strength of the wound was assessed by bursting pressure of the anastomotic site and the collagen content was determined by an hydroxyproline assay. Routine histology was also used. Sampling intervals of 1, 3, 7, 10 and 14 days post-anastomosis were utilized. The results indicated a significant reduction in wound strength as well as the collagen content in the experimental groups particularly at days 7 and 10. Control anastomoses gain their greatest increase in strength between days 3 and 7, as indicated by the bursting pressures. Experimental animals had this stage of the healing process delayed to between days 7 and 10. The ischemic interval effected a significant retardation in the wound healing process within the first 10 days. Both qualitative parameters had values exceeding those of normal rat colon in the control and experimental group by the 14th day following surgery. Although not always the case, the hydroxyproline values in this study reflected the differential in bursting pressures in both animal groups.