Does Silver Dressing Improve Equine Leg Wound Healing?

When it comes to healing horse wounds many owners will try any and everything to help the defect recover quickly—regardless of whether the product has scientific backing. Recently, researchers put some evidence behind one type of wound dressing: silver sodium zirconium phosphate polyurethane foam wound dressing, or, more simply, SPF dressing.

Maureen Kelleher, DVM, Dipl. ACVS, of the San Dieguito Equine Group in San Marcos, Calif., recently evaluated the SPF dressing's impact on equine wound healing, and she presented her results at the 2013 American Association of Equine Practitioners' Convention, held Dec. 7-11 in Nashville, Tenn.

The dressing is a semi-occlusive (meaning water and gas can still pass through while the wound is protected) polyurethane-based foam that includes ionic silver exchange resin and antimicrobial dyes believed to be useful in managing open wounds, Kelleher said. She and her team set out determine if the dressing improved second-intention healing (leaving a wound open to heal, rather than suturing it) of experimentally induced wounds on horses' lower limbs.

Kelleher and colleagues created 1 inch square wounds on each of six horses' forelimbs—one of each horse's legs served as a control and the other was treated with the SPF foam. Then they bandaged each leg, adding a 1 inch square pad with SPF foam to the test legs' wraps. The team changed the bandages every three days until the wound had healed and collected aerobic culture swabs on days the wraps were changed.

The team found that:

  • Wounds treated with the SPF dressing had significantly decreased wound areas through the study and decreased granulation tissue (commonly known as proud flesh) scores compared to control wounds;
  • There was no significant difference in healing time between the two groups, although the majority of the SPF treated wounds resolved slightly faster than control wounds; and
  • Bacterial growth was identified in all wounds at least once throughout the study period.

Kelleher cautioned that the wounds in the study don't reflect naturally occurring wounds and noted that additional studies are needed to evaluate the dressing's effects on clinical wounds.

She also noted that the dressing might not be cost-effective for large, draining, or purulent (pus-containing) wounds, but is more beneficial in smaller wounds with a mild to moderate amount of exudates (a high-protein fluid derived from blood and deposited in tissues or on tissue surfaces, usually as a result of inflammation).

Still, she concluded, "The SPF dressing was associated with significantly improved measures of wound healing in this experimental model."

Kelleher said the product is marketed as RTD (or Retro-Tech Dressing) and is available through Pioneer Vet and Animal Wound Care Worldwide.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.

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