Essential Insights On Using Skin Substitutes
Skin substitutes, which are also called bioengineered alternative tissues (BAT), are becoming more commonly used to help facilitate wound closure. Accordingly, our expert panelists discuss indications for these modalities and the timing of their use. They also weigh the benefits of skin substitutes versus skin grafts.
What is an appropriate wound condition for applying a skin substitute?
Eric Lullove, DPM, cites several appropriate wound conditions for the application of dermal skin replacement products. He says one may apply skin replacements in diabetic foot ulcers, venous stasis ulcers, burns of partial to full thickness, trauma, pressure ulcerations and for postoperative secondary wound closure.
Kazu Suzuki, DPM, CWS, and Desmond Bell, DPM, note the importance of ensuring the wound is thoroughly clean, free of infection and is covered with granulation tissue. Proper debridement, typically in serial fashion, can promote clean granulation tissue in the wound bed, according to Dr. Bell.
Kathleen Satterfield, DPM, concurs. “The recipient wound bed should look like the same surface on which we would apply a human skin graft — beefy red, non-fibrotic and clean with no signs of infection and callused edges debrided away,” she says.
However, Dr. Suzuki notes an exception may be Integra (Integra Life Sciences), a bovine collagen with silicone sheeting to prevent desiccation. He says one may apply Integra over some of the exposed bone and tendons, and then place another round of skin graft after Integra “takes” to the wound bed.
In addition, Dr. Bell notes that perfusion to the ulcer must be adequate and if it is not, one must address this prior to the use of a skin substitute. One should also rule out malignancy prior to use so he recommends a biopsy if the wound is suspicious based on history. Dr. Bell cautions against applying skin substitutes over ulcers in which there is necrotic tissue or a hyperkeratotic rim.
Is there appropriate timing for applying a skin substitute in chronic wounds?
The panelists cite research by Sheehan and colleagues that one should use skin substitutes in patients in whom ulcer size fails to reduce by half over the first four weeks of treatment.1 Dr. Bell says such patients are unlikely to achieve wound healing over a reasonable period. He adds that the study found that the percent change in foot ulcer area at four weeks’ observation is a robust predictor of healing at 12 weeks. Dr. Suzuki cites a similar study by Warriner and co-workers.2
Drs. Satterfield and Lullove note the importance of converting a chronic wound to an acute wound before using skin substitutes. Otherwise, Dr. Satterfield notes that one will only “totally misuse some excellent cutting-edge biotechnology” and the treatment will not work because the practitioner did not give it a chance to work. Dr. Lullove adds that one should assess arterial blood supply before any attempt at skin substitute replacement.
Is earlier use of skin substitutes warranted? Dr. Suzuki cites recent research by Kirsner and colleagues suggesting that the earlier one initiates an advanced biological therapy such as a skin substitute, the sooner the wound is likely to heal.3
“In other words, we probably should not ‘hold back’ these advanced biologic therapy but employ them proactively to get the wound to close as soon as possible,” argues Dr. Suzuki.
Dr. Bell agrees. “In an at-risk population, such as those with diabetes or venous disease, we know that nothing magical or good is going to happen by delaying more proactive treatment,” explains Dr. Bell. “Earlier use of skin substitutes should be encouraged as a way to ultimately help reduce morbidity and mortality.”