Delayed primary closure. Blood-flow in healing rat skin incisions.

In an earlier study delayed primary closure (DPC) wounds were shown to develop higher biomechanical strength than primary closure (PC) wounds. In order to elucidate the underlying mechanism, local clearance of 133Xenon and thermography studies were undertaken. A paired comparison design with deposits of 133Xenon injected in the wound margins 3 and 4 days postoperatively, and directly into the wound tissue 10, 20 and 60 days postoperatively was used. Very pronounced differences, with higher blood-flows for DPC wounds, were found in the early measurements. In the later measurements there were significant but less obvious differences. With thermography no differences could be detected. It is concluded that DPC wound have a higher blood-flow, especially in the initial wound healing phase. This supports the hypothesis that an increased blood-flowing during early wound healing is beneficial for the development of mechanical strength in the maturing normal scar.