The influence of age on the healing of normal and ischemic incisional skin wounds.

Experimental studies have not shown that the 'common' clinical experience, which suggests that wound healing is impaired in an old organism, is valid for healthy old experimental animals. We have developed a model in the rat for ischemic wound healing by using an H-shaped double skin flap, where the test wound is the horizontal line in the H. Our previous studies have shown that the blood flow in this wound is only 7% of that of a normally vascularized wound on the first postoperative day. Functional (biomechanical) properties of this wound are decreased by up to 67% after 10 days of healing and certain key properties by up to 64% after both 10 and 20 days. This study reports on the effect of aging, using 3- and 24-month-old rats. The 'normal' incisional wounds healed equally well in both groups. On the other hand, the ischemic wounds in the old animals were found to be impaired by 40-65% compared to similar wounds in the young animals. It is concluded that ischemia is deleterious for wound healing in old age and that one of the key elements of the clinical experience of impaired wound healing in old age is probably based on concomitant diseases in old patients, contributing to varying degrees of ischemia in the traumatized tissue.