Closed incision Negative Pressure Therapy (ciNPT): does depression affect underlying tissues?

Closed incision Negative Pressure Therapy (ciNPT) has become a widespread practice in recent years. Described benefits concern the rate of wound infection, based on the assumption that negative pressure spreads inside the wound removing collections and edema. The study aims to clarify this technical point, on which experimental scientific evidence is lacking in literature. In the experimental animal (newly sacrificed pig), the pressure was measured for hours at the bottom of three surgical abdominal wounds sutured by planes and dressed in negative pressure therapy commercial sets. The depression applied to the surface of the sutured wounds (ciNPT) is not transmitted to the underlying tissues. The blue dye deposited in the deep layer of the wounds didn't surface as an effect of ciNPT. The possible benefits deriving from the application of negative pressure on sutured wounds must depend on a different mechanism from the diffusion of depression in the wound planes and in the underlying tissues.