Negative pressure wound therapy is an advancement in wound treatment that has benefits. It is particularly useful in wounds where a cavity or significant defect in the tissues has occurred. In flat superficial ulcers it seems to have minimal benefits. In wounds where there is a loss of deeper tissue as well as skin the defect needs to fill up before closure of the skin can take place and it is this filling up which is accelerated by using a vacuum dressing. Once a wound is clean, and provided it has a good blood supply, application of negative pressure devices speed up the filling in of the wound. The negative pressure also tends to draw the edges of the wound together to facilitate healing. Any fluid or exudate weeping across the wound is better controlled and dressing changes can be less frequent. Negative pressure is usually applied at -80 to -125 mmHg for an adult and is suitable for the majority of wounds providing they are clean. The main contraindication to negative pressure wound therapy is when deeper structures such as bone or blood vessels are exposed in a wound.
There are now a number of commercial devices on the market that provide negative pressure to wounds and the whole field has become specialised. Debates on continuous suction versus intermittent suction, how much negative pressure to apply, what type of dressing should be under the suction and the advantages of different devices cloud the main point that negative pressure assists wounds heal virtually however it is applied.