Topical negative pressure improves autograft take by altering nutrient diffusion: A hypothesis

The one-step surgical procedure for dermal substitutes combined with topical negative pressure (TNP) has proven effective for treating deep skin defects with improved graft take. The primary mechanism by which TNP improves autograft take is unknown. Some studies suggest that TNP promotes the rapid angiogenesis of dermal substitutes, improving graft take. However, at the early stage of one-step transplantation, the vascular system has not formed and imbibition is the main mode of nutrient supply. TNP can shorten the diffusion distance from the wound bed to the graft, leading to the timely renewal of the wound exudate via suction, removing any surplus exudate, and reducing tissue edema. In addition, TNP can regulate the local blood flow and inhibit bacterial colonization. Therefore, we hypothesized that TNP establishes a rapid balance between the nutrient supply to the wound bed and nutritional requirement of the graft via these pathways in the relatively closed, moist environment, improving autograft take. However, this balance could be affected by any negative pressure, intermittent or continuous. It is necessary to test this hypothesis in laboratory and clinical studies of the mode of nutrient supply in the imbibition phase and the change in exudate content.