Vacuum assisted wound closure (VAC) has been used for difficult to treat wounds, pressure sores, chronic nonhealing wounds, diabetic associated wounds, and to secure skin grafts in people. The main advantage of this technique is speeding the formation of granulation tissue within the affected site and the reduction of peri-wound edema.

VAC technically is the application of controlled, intermittent negative pressure to a wound bed to enhance healing. Veterinary patients do not seem to appreciate the cycling on and off negative pressure, so continuous negative pressure is usually applied to the wound. Most bandage changes are done with sedation, so the initial application of negative pressure does not seem to cause significant discomfort. Minimal or no secondary layers are required, making most patients quite comfortable and mobile during VAC therapy, which is another great benefit of the technique. Commercially available, small pumps are used in human medicine and are now available in veterinary medicine, allowing patients to be walked with minimal changes to the system. The system is closed, so it allows measurement of wound exudate and evaluation of its gross character. The fluid is removed from the wound bed, use of and strike through of a padded bandage is avoided which minimizes contamination, and VAC can be applied to many sites that are typically difficult to bandage. All are more benefits of VAC over typical bandaging. There may be added benefits of decreased bacterial numbers on the wound bed, and the system is not approved for, but it has been used by the author to decrease dead space over time and for debriding small sections of wound beds that are not yet ready for granulation.

The VAC works through mechanical forces/stress on the wound bed, it removes and changes cytokine gradients across the tissue, and it decreases periwound edema. There is a known increase in mitotic rate and increased tissue ingrowth during bone distraction using the Ilizarov technique, and the VAC likely does the same.

The altered wound fluid and cytokines may change DNA transcription, and decreasing peri-wound interstitial edema opens more capillaries and restores blood flow. Known effects include increased capillary blood velocity and volume as and increased stability of basement membranes. Other effects include increased neutrophil numbers, increased angiogenesis, and increased tissue oxygenation.

The contact layer of the system is open cell foam, which allows controlled (regulated) negative pressure to the entire wound surface. The foam is connected to the pump, and a seal that excludes the environment and maintains the negative pressure is vital to the system.

First perform normal wound care per standard therapy. Clip, clean and lavage the area. Surgical debridement should be done as necessary, but 24 h prior to application of the VAC to avoid significant blood loss. Debridement via hydrocolloid bandaging should be done and complete prior to VAC. Cut the foam to match the wound bed, then insert a large catheter into the foam or use the prefabricated kit after covering the wound with adherent bandage material. Connect the catheter to the pump, and apply negative pressure. Listen for air leakage into the bandage and makes sure that the foam compresses and remains compressed after instituting negative pressure. Secure the catheter to the patient in a comfortable pattern allowing mobility. Maintenance of the VAC simply requires ensuring no breaks in the seal and ensuring negative pressure. Change the first VAC bandage at 24 h to evaluate the response to therapy, but thereafter the bandage may be changed every 48–72 hours.

Contraindications to VAC include malignancy in the wound, exposed blood vessels, necrotic tissue, untreated osteomyelitis, active bleeding, and the presence of a coagulopathy. The use of VAC on abdominal sepsis will also be described.

Skin stretching is based on the old concept of pre-suturing, in which the skin surrounding a mass lesion was temporarily sutured over the mass the day prior to removal. Velcro can be glued and sutured to the patient following wound management or to assist with wound management. The skin surrounding the wound may be progressively stretched to increase the skin available for wound closure 72–96 or more hours after application. Skin stretching also allows for compression of the contact layer to the wound bed, which is appropriate for bandage debridement, but care should be taken with granulation tissue. Skin stretchers may be used to bandage difficult (dorsal) areas and can remain in place following surgery to minimize tension on the closure if necessary.