Effect of local hypothermia on early wound repair.

Local hypothermia has been shown to enhance survival of pedicled skin flaps. The effect of prolonged local hypothermia on an important clinical correlate, wound healing, is examined in this study. Skin incisions were made on each flank of nine female pigs, and these incisions were closed primarily. A cooling pad was applied over the incisions on the right side of each animal, achieving an average dermal temperature of 35 degrees C vs 39 degrees C for the control side. Four animals were treated for 72 hours postoperatively; five pigs were treated for 7 days. Wound repair was evaluated by standard histologic techniques at 24 hours, 72 hours, 7 days, and 14 days. Control wounds in all animals demonstrated the normal progression of primary wound repair. We demonstrate that local hypothermia: (1) inhibits wound repair for the duration of its application; (2) is not detrimental to the early 2-week phase of wound healing if applied for 72 hours postoperatively; and (3) may have a beneficial effect by inhibiting inflammation through delay of the late inflammatory phase of wound healing.