Evaluation of microcirculation and wound-closing tension after undermining the skin. A study in a porcine model using laser Doppler perfusion imaging

Undermining the skin can reduce wound tension when closing skin defects and thereby can provide a potentially better microcirculation. On the other hand, undermining causes damage to blood vessels. In this study the relationship between wound tension and microcirculation in undermined wounds was evaluated. A porcine model was used and in three pigs six undermined excisions and six control excisions were done. The tension needed to close the wound was noted and the postoperative microcirculation was measured with a laser Doppler perfusion imager. Undermining the skin gave significantly reduced (p<0.05) wound-closing tension with a mean decrease of 25% (95% CI: 17–33%). The postoperative microcirculation in the undermined wound was significantly reduced (p<0.05) with a mean of 28% (95% CI: 8–46%). Undermining the skin reduced the wound-closing tension. In our model the positive effect on the microcirculation by reducing the wound-closing tension was less than the negative effect of cutting the perforating blood vessels to the skin with a net decrease in blood flow.