Can Microcirculation Changes Predict Non-Healing Ulcers?

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By Brian McCurdy, Associate Editor

   Researchers of a recent study say assessing microcirculation changes may help predict whether diabetic foot ulcers will heal. The authors of the study, which was published in a recent issue of The Lancet, utilized medical hyperspectral imaging to perform these assessments and add that the new technology may help identify patients with diabetes who are at higher risk for foot ulcers.    Researchers of the study examined 108 patients, including 51 patients with diabetic neuropathy, 36 with diabetes but no neuropathy and 21 control patients without diabetes. The authors employed the HyperMed Visible MHSI System (HyperMed Inc.), to measure the hemoglobin saturation in patients’ forearms and feet. They also utilized 31P-MRI scans to examine the cellular metabolism of foot muscles by determining and measuring inorganic phosphate and phosphocreatine concentrations.    While the foot was at rest, researchers found hemoglobin saturation was higher in the control and non-neuropathic groups than in the neuropathic patients. The inorganic phosphate/phosphocreatine ratio was higher among patients with diabetes (those with and without neuropathy) than in the control group, according to the study. The study concluded that hemoglobin saturation is lower in the skin of patients with diabetes and the presence of neuropathy exacerbates such an impairment. The foot muscles’ energy reserves are also lower in patients with diabetes and the authors suggest this can be attributed to microcirculation.    John Giurini, DPM, says one day clinicians may use the new technology to predict the healing capacity of diabetic ulcers. The MHSI System examines blood flow and oxygen tension at ulceration margins and he calls this testing more predictable, quantitative and specific than TcPO2 in predicting non-healing ulcerations.     “We believe that tracking skin and metabolism changes will be very helpful in identifying people who fail to heal existing foot ulcers,” adds co-author Aristidis Veves, MD, the Research Director of the Microcirculation Lab at the Joslin-Beth Israel Deaconess Medical Center in Boston. “Tracking skin oxygenation may also be helpful in identifying diabetic patients at risk of developing foot ulcerations.”

What Does The Future Hold?

   Although study authors tout the MHSI technology as effective, it is cumbersome and its costs would be prohibitive for day-to-day use in a podiatric setting, according to Dr. Giurini, Chief of the Division of Podiatric Surgery at the Beth Israel Deaconess Medical Center in Boston. However, as studies continue, he notes the goal is to create a practical system that would be easily accessible to all physicians.    Where will future research lead? Drs. Giurini and Veves say they are currently formulating studies that will examine the effect of numerous factors, including exercise and metabolic syndromes, that influence tissue oxygenation and muscle metabolism.

Study Says NPWT Can Reduce Risk Of Second Amputation

By Brian McCurdy, Associate Editor    Patients with diabetes who have undergone partial diabetic foot amputation face a potential for complications, including the risk of a second amputation if the wound does not heal. Can negative pressure wound therapy (NPWT) prevent such complications? A recent landmark study in The Lancet concludes that patients who have undergone NPWT had a higher percentage of healing and a trend toward a reduced risk of undergoing another amputation than those who received standard wound care.    The randomized, multicenter trial involved 162 patients who had undergone partial diabetic foot amputations to the transmetatarsal level. One study group received NPWT (Vacuum Assisted Closure Therapy, KCI) while a control group received standard moist wound care.    In the trial, 56 percent of the NPWT group healed compared to 39 percent of the control group. Researchers concluded that wound healing and granulation occurred more quickly in the NPWT group than the control group. Study authors say using NPWT can potentially reduce the risk of a second amputation, noting that those who underwent NPWT were 25 percent less likely than the control group to have a second amputation.    The authors state that most of the previously published clinical support for NPWT was based on the perceptions of clinicians, case series, small cohort studies and “less robust” randomized trials that added up to “a low amount of evidence” despite published articles in a wide array of journals. Authors of the Lancet study included patients with wounds seven to eight times larger than those examined in previous trials, saying other studies focused on smaller neuropathic wounds.    The VAC will work best in patients with the most need for the therapy, says study co-author David G. Armstrong, DPM, MSc, PhD. He adds that many products in a similar vein “seem to work best when they are needed the least. Previous trials were not designed to test them when they were needed the most.”

Assessing The Pros And Cons Of VAC Therapy

   Although several devices can provide wound suction, VAC therapy seems to work well, says Dr. Armstrong, a Professor of Surgery, Chair of Research and Assistant Dean at the Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science. He says the device is unique as it combines subatmospheric pressure with polyurethane foam, which he cites as “an exceedingly effective wound interface.” Dr. Armstrong cites theories that suggest that such a combination succeeds because it causes microdeformations in tissue and stimulates “cell stretching,” causing cells to divide and proliferate.     “When you combine this with the natural action of reducing edema and removing potential infectious or inflammatory exudate, you have a very powerful system,” says Dr. Armstrong, an immediate past member of the National Board of Directors of the American Diabetes Association.    Dr. Armstrong encourages further investigation into the cellular effects of NPWT to wounds and the therapy’s effect on other types of wounds than the diabetic wounds studied.    On the downside, Dr. Armstrong does note that VAC therapy, like many modalities, is expensive purely when one analyzes the front-end costs. However, he says the cost may not be substantial when one factors the length of a hospital stay and a prolonged return to activity and employment into the economic equation. He suggests that further research could concentrate on pharmacoeconomic analyses of the technology.

Shockwave Therapy: New Study Cites Benefits In Treating Plantar Fasciitis

By Brian McCurdy, Associate Editor    While extracorporeal shockwave therapy (ESWT) has been the subject of much discussion and study over the years, a recent study reveals that a majority of patients who have undergone ESWT experience less pain and greater mobility.    The study, which was published in a recent issue of the Journal of the American Podiatric Medical Association (JAPMA), examined post-treatment surveys of 353 patients who had received shockwave therapy for plantar fasciitis. Seventy-six percent of the patients had pain for at least a year. Among those who rated their pre-treatment pain as 8 or higher (on a scale of 1 to 10 with 10 being the worst pain), 70 percent related a “sharp decline” in pain, according to the study. The authors of the study also point out that 66 percent experienced “sharp declines” in immobility following treatment.    Patients underwent shockwave treatment via the electrohydraulic OssaTron (SanuWave, Inc.) and the electromagnetic Epos devices (Dornier MedTech America, Inc.). As Dr. Werber notes, both devices were equal in terms of their outcome and efficacy.    Will the beneficial effects of shockwave stand the test of time? Kimberly Eickmeier, DPM, a co-author of the study, says if patients wear their orthotics as indicated postoperatively, they will not experience reoccurrences. She notes a lack of reoccurrences internationally since shockwave therapy was introduced overseas in 1991. Co-author Bruce Werber, DPM, concurs, saying time will bear out the effects of ESWT technology. He adds that the use of the technology by DPMs may also change over time with increased understanding of its effect on the tissues treated.    Drs. Eickmeier and Werber warn that one should use shockwave for patients with chronic rather than acute heel pain. If patients have not responded after three to six months of treatment with stretching, shoe gear and other modalities, one should then begin shockwave treatment, according to Dr. Werber, a Fellow and Past President of the American College of Foot and Ankle Surgeons.    Dr. Eickmeier, who practices at Christie Clinic in Champaign, Ill., believes using ESWT can save costs by avoiding heel pain surgery and these savings can offset the costs of the shockwave devices themselves.    She notes the equipment costs about $350,000 in the United States but costs are about one-third of that in Europe where the technology has been in use longer and greater demand has driven down the costs. Dr. Eickmeier, who serves on the board of the International Society for Musculoskeletal Shockwave Therapy, believes ESWT devices may become cheaper in the United States as more devices gain FDA approval. She notes shockwave devices are available in 41 states via mobile providers and DPMs can contract with a mobile service or a hospital.    Dr. Werber also notes shockwave use may have economic benefits. “I think the cost benefit analysis should make the utilization of ESWT technology more accepted on many levels,” he says. “I do believe that we need more cost data and outcomes data as the cost factors of surgery versus ESWT still need to be evaluated. I think ESWT will be more cost effective versus surgery and/or by decreasing the amount of disability and time lost from work.”

In Brief

   Pedinol Pharmacal Inc. has established a Web site (www.nalfon200.com) dedicated to fenoprofen calcium 200 mg (Nalfon). Nalfon is a nonsteroidal antiinflammatory drug, a non-selective COX-1 and COX-2 inhibitor indicated for pain due to rheumatoid arthritis and osteoarthritis, according to Pedinol.

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