There are a variety of advanced treatment options that can help expedite wound healing. Accordingly, these expert panelists offer insights on the use of negative pressure wound therapy (NPWT) and growth factors, and the emergence of stem cell therapy.
Q: Do you have any pearls in prescribing NPWT?
A: Lawrence Lavery, DPM, cites NPWT as one of his standard therapies for open amputations or patients with exposed tendon or capsule after a debridement of foot ulcerations. He says negative pressure facilitates drainage and the formation of granulation tissue over structures that are otherwise difficult if not impossible to cover. Dr. Lavery cites research showing significant differences in the quality of granulation tissue in patients treated with NPWT for open amputation wounds and diabetic foot ulcers.1,2
Kazu Suzuki, DPM, recommends NPWT for patients with any gaping wound or large defect that may need assistance in granulation. He says any diabetic foot amputation wound or heel pressure ulcer warrants NPWT unless the wound or ulcer is very small and shallow (less than 0.5 cm depth) with minimal drainage.
For Eric Travis, DPM, NPWT plays an integral part in wound treatment and he praises the modality’s versatility and consistent results. He will use NPWT after ensuring that he has addressed the essential variables with non-healing or “difficult” wounds. Dr. Travis notes the importance of addressing variables such as infection, circulation, oxygenation, nutrition and pressure (edema/ morphological) and consulting with infectious disease, endocrinology and vascular surgery if necessary.
After addressing these variables, Dr. Travis addresses the wound environment. In his experience, NPWT is most successful after debridement and with continuous 125 mmHg suction. For inflamed and/or painful wounds, he lowers the settings and will switch to intermittent suction with chronic ulcers. Dr. Travis utilizes enzymatic debridement with NPWT when sharp debridement is not indicated as with some venous stasis ulcerations and in patients with connective tissue disorders. He has also used NPWT for a majority of his graft applications and when there is wound dehiscence in high-risk patients.
While he does not have artificial age restrictions on NPWT, Dr. Suzuki has had problems with the patients with dementia who ripped out the dressing repeatedly. He emphasizes caution with frail patients who may have trouble carrying the device and may recommend a wheelchair as needed when these patients are using negative pressure.
Dr. Suzuki uses VAC therapy (KCI) exclusively for negative pressure in his wound care center, citing his familiarity with how VAC therapy works and its ordering process.
“KCI’s VAC therapy has been on the market over 10 years. I have no reason to try the competing products until they show comparative or better clinical outcomes,” says Dr. Suzuki.
He praises the efficacy of NPWT for securing skin graft and flaps, as well as its “graft-take” rate. When it comes to this application, Dr. Suzuki uses a non-adherent interface such as Mepitel (Molnlycke) and lowers the suction pressure of NPWT down to a 75 to 100 mmHg continuous setting.
“My ‘sales pitch’ of VAC therapy to my patients is, ‘This device will make you better two to three times faster’ and most patients would agree to try it,” says Dr. Suzuki.
Q: Do you use stem cell therapy or other growth factor medications in the wound care setting?
A: Along with his Japanese collaborators, Dr. Suzuki has tried autologous stem cell injections in ischemic lower extremity wounds. Although the profession does know that such injections often help relieve the ischemic wound pain, he says definitive data on wound healing or angiogenesis has yet to emerge. He feels it will be a few more years before the development of evidence-based treatment protocols on autologous stem cell injections.
When it comes to platelet rich plasma (PRP) centrifuge systems, Dr. Suzuki says such technology is promising. However, he urges caution until these modalities have solid evidence behind them.
“I believe we have to be critical when evaluating these ‘new and exciting’ therapies,” maintains Dr. Suzuki. “Until we can develop evidence-based wound care protocols using new biologic products such as PRP, I prefer to stick with proven ‘best care’ wound care therapies such as surgical debridement, VAC therapy and hyperbaric oxygen therapy.” Dr. Suzuki also notes that PRP and stem cell therapies are considered “experimental” and are largely non-reimbursable.
Dr. Travis says PRP is comprised of an assortment of autologous growth factors that synergistically improve wound healing. As he expounds, the mixture of concentrated autologous platelets with calcified thrombin cause a secretion of serotonin, fibronectin, platelet derived growth factor (PDGF), platelet-activating factors and other growth factors. Dr. Travis explains that these factors induce a chemotactic response and process a migration of endothelial cells, which increases angiogenesis, osteogenesis and the formation of granulation tissue.
In wound care, Dr. Travis cites the effective use of cellular and acellular wound matrices, including live keratinocytes, fibroblasts, collagen, glycosaminoglycans, proteins and various growth factors. Dr. Travis has used PRP with several wounds in which he has incorporated grafts such as Apligraf (Organogenesis). He selects patients for this therapy if they have connective tissue diseases such as scleroderma and wounds that typify a delayed healing environment. However, Dr. Travis says most wounds would benefit from this therapy.
“It appears that incorporating the stem cell therapy of PRP allows the cellular signaling molecules to direct the stem cells to fill the gaps, restoring the entire tissue compartment to the wound bed,” offers Dr. Travis. “Successful incorporation of the graft matrix to the recipient site is key in healing these difficult wounds.”
Both Dr. Travis and Dr. Suzuki cite the use of becaplermin (Regranex, Systagenix) PDGF gels in accelerating the wound healing. However, Dr. Suzuki notes that the treatment protocol is somewhat demanding (once a day application and the need for refrigeration). He adds that not all his diabetic foot wound patients may be candidates for Regranex gel. Dr. Lavery adds that Regranex is expensive and its clinical efficacy “has not seemed to live up to” the randomized controlled trials.
Most skin substitutes — such as Apligraf, Dermagraft (Advanced Biohealing) and Oasis (Healthpoint) — contain various growth factors, and Dr. Suzuki considers them as “growth factor supplementation” in some patients. He notes the availability of dozens of new skin substitutes from human cadaver and bovine and other animal sources for wound healing and tissue augmentation. Dr. Suzuki adds that this “competition is always good” for doctors and patients.
Dr. Travis notes the recent emergence of gene and stem cell therapies as promising approaches for chronic and acute wound treatment. He cites the widespread clinical applications of stem cell therapy.
However, Dr. Lavery is skeptical. “Stem cell therapies are still not ready for prime time,” he says. Although there is one study at the University of Miami on stem cells for wounds, he notes there are no commercially available products.
Dr. Lavery is a Professor in the Department of Surgery at Texas A&M Health Science Center College of Medicine.
Dr. Travis is on the teaching staff at Fountain Valley Regional Hospital and is involved in the Wound Care Program at La Palma Intercommunity Hospital in La Palma, Calif. He is in private practice in Huntington Beach, Los Alamitos and Seal Beach, Calif.
Dr. Suzuki is the Medical Director of Tower Wound Care Center at the Cedars-Sinai Medical Towers. He is also on the medical staff of the Cedars-Sinai Medical Center in Los Angeles and is a Visiting Professor at the Tokyo Medical and Dental University in Tokyo, Japan.
1. Armstrong DG, Lavery LA. Negative pressure wound therapy after partial diabetic foot amputation: a multicentre, randomised controlled trial. Lancet 2005 Nov 12;366(9498): 1704-10. 2. Blume PA, Walters J, Payne W, Ayala J, Lantis J. Comparison of negative pressure wound therapy using vacuum-assisted closure with advanced moist wound therapy in the treatment of diabetic foot ulcers: a multicenter randomized controlled trial. Diabetes Care 2008 Apr;31(4):631-6.