Negative Pressure Wound Therapy – A future game changer in the companion animal space?

Little piglet in piggery with innocent eye.

Negative Pressure Wound Therapy (NPWT) is an important clinical tool in the human healthcare population and in many ways has revolutionised the treatment of acute and chronic complex wounds. It is widely used to assist with rapid formation of granulation tissue and to decrease time for wound healing.

The documented success in the human population is well established with many published papers including animal studies confirming the benefits. It provides a promising opportunity for the companion animal and equine populations. Whilst lagging someway behind in the veterinary space it is becoming more popular especially to help manage problematic wounds.

NPWT promotes a favourable wound healing environment. Once applied the closed system protects the tissues against trauma and contamination, leaving the tissues moist whilst removing exudates and infectious materials. At a visible level, subatmospheric pressure helps reduce oedema, dead space and promotes contraction, and at a cellular level, benefits include improved tissue perfusion, fibroblast migration and cellular proliferation.

While there are some contraindications, for example with malignancy or unexplored fisutulas, many wounds from simple lacerations through to severe abscesses, deglovings, skin flaps and grafts can be helped to heal with NPWT.

Results from the case study outlined below provide one such example of the potential to positively impact wound healing outcomes.

To quote the doctor who cared for this patient “I would have really struggled with the case without it.”

Izzy is an 11 year old FS Bull Arab Cross who underwent wide surgical excision of a cutaneous haemangiosarcoma, located along the medial aspect of her left stifle. She was treated by the team at Queensland Veterinary Specialists led by Dr Guy Bird.

A flank fold rotation flap was utilised to close the resulting skin defect. Unfortunately, approximately 10 days postop the distal aspect of the wound, that was located over the stifle, began to dehisce.

A tie-over bandage was placed, with a hypertonic saline primary dressing. Unfortunately, at home Izzy was able to pull off the tie-over dressing, even whilst wearing a suitably large E-collar. She was then subsequently hospitalised for continued wound management, as the wound was not making any progress and her owners were not able to keep her appropriately confined.

Whilst in hospital a tie-over bandage dressing was continued with unsatisfactory wound progress. The wound became extremely exudative and her limb became very edematous, inflamed and painful to touch.

There was concern that the wound was becoming infected. A lack of progress was evident in the challenging open wound environment, in a very mobile area, with approx 5-8 cm of dead space, peripheral to the wound edge.

As a result, the decision was made to trial NPWT.

The Dressing remained in place and Izzy did not appear to be bothered by the dressings or NPWT unit.

The dressings were changed every 3-5 days, which enabled closer monitoring of the wound bed. At no point was there a need to change the bandage due to slippage or loss of vacuum. The unit never lost negative pressure. Immediate advantages of the NPWT device meant there was no need to obtain a wound culture nor was Izzy placed on antibiotics.

4 days post NPWT application

7 days NPWT post application

12 days NPWT post application

As demonstrated by the image series, the wound became less exudative, the limb oedema resolved and the skin edges adhered down to the granulation tissue (peripheral dead space was been obliterated).

At this point the wound was starting to contract and epithelialise – NPWT was ceased.

In this instance, the Cardinal Health NPWT system, supplied by Dr Sebastian Menzies at Fourlimb Surgical Solutions, did what would have been very difficult for any other treatment option to achieve. It closed dead space, reduced limb oedema and prevented infection which saved on antibiotics and culture.

The Cardinal Health NPWT system is ideally suited for veterinary use.

  • Heat activated adhesive drapes form a strong long lasting seal.
  • Sufficiently long large lumen tubing and connectors allow rapid connection and reduces the likelihood for kinking or obstruction.
  • Black foam dressing that can be trimmed to size without fraying and leaving fibres in the wound.
  • The device itself is small, light and can run on battery for hours to allow the animal to be moved and exercised without disconnection.
  • It is simple to use and includes the ability to adjust the pressure setting or use variable therapy mode.
  • Simultaneous irrigation can be used to decrease bioburden in infected wounds.

The ultimate aim when dealing with any wound is to return the animal to pain free full function as soon as possible. NPWT helps create an optimal environment to promote wound healing. Fourlimb Surgical Solutions can assist with simple, reliable and flexible options to meet a variety of veterinary clinical needs/scenarios. With the support of Fourlimb the use NPWT is now a viable and valuable tool to better manage wounds in veterinary clinical practice.

Morykwas MJ et al Vacuum-assisted closure: a new method for wound control and treatment: animal studies and basic foundation – 1997
Borgquist O et al Wound edge microvascular blood flow during negative-pressure wound therapy – 2010
McNulty AK et al Effects of negative pressure wound therapy on fibroblast viability, chemotactic signaling, and proliferation in a provisional wound (fibrin) matrix – 2007
Demaria M, Stanley BJ et al Effects of Negative Pressure Wound Therapy on Healing of Open Wounds in Dogs – 2011
Malmsjo M et al The effects of variable, intermittent, and continuous negative pressure wound therapy, using foam or gauze, on wound contraction, granulation tissue formation, and ingrowth into the wound filler – 2012

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