Intestinal anastomotic healing at varying times after irradiation

The use of preoperative and intraoperative irradiation as surgical adjuncts in cancer management has led to concerns regarding post-operative wound healing. The optimum time to construct an intestinal anastomosis after irradiation has not been determined. The aim of this study was to evaluate anastomotic wound healing at varying times after irradiation. One hundred eighty-seven male Sprague-Dawley rats were randomized into seven experimental groups. Group I (control) had a sutured anastomosis and no irradiation. Groups II-VII received a single dose of 20 Gy intraoperatively. In group II, a sutured anastomosis incorporating irradiated bowel was performed immediately after irradiation. Groups III-VII underwent a second laparotomy to undergo a sutured anastomosis with irradiated bowel at 2 days, 1 week, 2 weeks, 3 weeks, and 4 weeks after irradiation. The rats were sacrificed 7 days after the anastomosis was created and the segment of terminal ileum containing the anastomosis was harvested. Tensile strength, hydroxyproline content, and modified Black irradiation damage scores were determined: [table: see text] The increasing modified Black scores reflect the progressive nature of irradiation damage over time. Increasing hydroxyproline content is seen after irradiation but this does not imply increasing wound strength. There was a return of tensile strength to normal levels by 2 weeks. These findings suggest that normal wound healing can be expected if a minimum of 2 weeks elapses between irradiation and intestinal anastomosis.