Postoperative irradiation impairs or enhances wound strength depending on time of administration.

Irradiation can complicate surgical wound healing, yet little is known of the importance of the time between surgery and irradiation on this process. This study investigated the impact of postoperative irradiation on gain in would tensile strength in a murine skin model. Irradiation on the same day as wounding or to 2-day-old wounds reduced wound tensile strength. In contrast, postoperative irradiation delivered at 7, 9 and 14 days transiently enhanced wound tensile strength, as measured 3 but not 4 or 5 weeks later. This effect was independent of the inclusion (hemibody) or exclusion (skin alone) of the hematopoietic system in the field of irradiation. Radiation-enhanced wound tensile strength was greater and occurred earlier after higher radiation doses. Even though the effect of irradiation in enhancing wound tensile strength is transitory, it could be important in assisting early wound healing.