Study Says NPWT More Effective Than Moist Dressings For DFUs

Brian McCurdy, Senior Editor

Negative pressure wound therapy (NPWT) is more effective than advanced moist wound therapy in facilitating the closure of diabetic foot ulcers and reducing secondary amputations. These are the findings of researchers who recently published the largest randomized, multicenter, controlled trial on NPWT.
In the study, which was published in Diabetes Care, researchers randomized 169 patients to VAC Therapy (KCI) and 166 patients to advanced moist wound therapy (primarily hydrogels and alginates). Patients had stage 2 or 3 (as per the Wagner scale) calcaneal, dorsal or plantar ulcers. Researchers determined that within the 112-day active treatment phase, 43.2 percent of NPWT patients achieved wound closure in comparison to 28.9 percent of patients who received moist dressings.
Furthermore, NPWT patients underwent significantly fewer amputations, with researchers citing a 4.1 percent amputation rate for the NPWT patients in comparison to 10.2 percent for the moist dressings group.
Lee Rogers, DPM, has found that NPWT can simplify complicated wounds. In a matter of days, Dr. Rogers says the technology can convert deep wounds with exposed subcutaneous structures into shallow wounds with granular tissue. He adds that the granular tissue is “extremely vascular and of high quality.
“I would argue that NPWT is the ‘standard of care’ for deep, complicated wounds,” says Dr. Rogers, the Director of the Amputation Prevention Center at Broadlawns Medical Center in Des Moines, Iowa.
Luis Leal, DPM, has found NPWT to be more effective than moist dressings. He also notes the increased promotion of granulation tissue, which permits him to plan definitive closure of the wound.
As far as advantages, he notes the shorter nursing time and the ability to transition patients to a subacute setting, reducing the length of hospital stays. Dr. Leal, the Director of the Wound and Limb Healing Institute at Palisades Medical Center in North Bergen, N.J., also cites the reduced number of secondary amputations.

Some Caveats To Keep In Mind
Dr. Rogers says physicians should avoid using NPWT to the point of complete wound closure, noting that this is a problem in several studies. Ideally, Dr. Rogers says it is best to use NPWT to promote granular tissue formation. After achieving granulation tissue, he says podiatrists can close the wound easily with a skin graft, surgical flap or skin substitute.
As for disadvantages to NPWT, Dr. Rogers notes there are few. However, one can mitigate any maceration, odor or pain during therapy, according to Dr. Rogers.
“The benefits of use far exceed the risks of not using NPWT,” maintains Dr. Rogers.
Dr. Leal notes a tendency of more infections in VAC therapy patients in comparison to patients who use moist dressings. He also says there is an inherent danger due to improperly placed devices. Cost is another downside, notes Dr. Leal.
“In my eyes, a major issue with NPWT remains the lack of basic science and research concerning (the modality),” continues Dr. Leal. “We know it works. However, we do not know why it works at the gross or cellular level, and many of the theories espoused are counterintuitive.”
Patient compliance is usually not a problem with NPWT, according to Dr. Rogers, who says patients generally change the dressing every three days. If the patient uses negative pressure at home, he says this requires either a home care nurse with experience in NPWT or the patient must have the dressing changed in the clinic.

MIRE No More Effective Than Sham For Diabetic Neuropathy
By Brian McCurdy, Senior Editor

Monochromatic infrared photo energy (MIRE) is among the current treatments that physicians employ for treating the symptoms of diabetic neuropathy. However, a recent study in Diabetes Care downplays the effects of MIRE with researchers criticizing the previous positive literature on the treatment. The study concludes that MIRE is no more effective than a sham treatment as far as improving sensory neuropathy, pain or balance.
In the double-blind, randomizedclinical trial, the authors examined 60 patients with diabetes and a vibration perception threshold (VPT) between 20 and 45 V. Patients received either MIRE treatment or a sham. The MIRE group used Anodyne (Anodyne Therapy) at home for 40 minutes a day over a 90-day period.
The researchers evaluated nerve conduction velocities and VPT. According to the study, they utilized Semmes-Weinstein monofilaments (SWM), the Michigan Neuropathy Screening Instrument (MNSI), a 10-cm visual analog pain scale, and a neuropathy-specific quality of life instrument. They tested the great toe and the fifth metatarsal on the left and right feet of each patient. The study concluded that MIRE did not provide improvement in peripheral sensation, balance, pain or quality of life.

Examining The Previous Literature On MIRE
Study author Lawrence Lavery, DPM, notes that existing research on MIRE is “not done well and has serious flaws.” For example, he says one of Leonard’s previous studies did not include the data from the entire study population in the analysis. Instead, authors stratified the study population and evaluated them separately, focusing on evaluating supgroups with moderate and severe neuropathy, according to Dr. Lavery. He feels it would be likely that there would not be a significant effect on sensory neuropathy in the MIRE group if the entire patient population had been included in the analysis.
Furthermore, he notes that an examination of the data in previous studies suggests that although there was a marginal improvement, there was not a clinically meaningful change over time between the active and sham treatments.
Although the MIRE data for wound healing is “very poor,” Dr. Lavery notes practitioners are still using the therapy for patients with diabetic neuropathy. “The evidence indicates that (MIRE) does not work any better than sham,” says Dr. Lavery. “I think (DPMs) need to ask themselves if they are wasting time, effort and money on an ineffective therapy.”
Where should future research into this topic lead? Dr. Lavery, a Professor in the Department of Surgery at Texas A&M Health Science Center College of Medicine, says researchers need to use double-blinded, randomized, controlled trials to evaluate modalities for painful neuropathy, balance and wound healing.


Researchers Find Favorable Outcomes For Charcot Reconstruction
By Brian McCurdy, Senior Editor

How do patients with diabetic Charcot neuroarthropathy fare following reconstructive procedures? One retrospective analysis found favorable outcomes following Charcot diabetic foot reconstruction.
Researchers studied 44 consecutive patients who had undergone 50 reconstructive salvage procedures for diabetic Charcot neuroarthropathy over a three-year period. The surgical procedure involved Achilles tendon lengthening, anatomical realignment with internal fixation, the use of autologous growth factors at fusion sites and external fixation compression.
In a poster presentation at the annual meeting of the American College of Foot and Ankle Surgeons (ACFAS), the study authors said all patients reported an increased ability to walk and had significant relief from pain. In addition, the authors say the study shows that “all types of Charcot diabetic deformities can be managed surgically” as long as one ensures careful preoperative planning.
Charcot reconstruction decreases the chance that patients will have further ulceration, notes poster co-author William Grant, DPM. He points out that no patient in the study developed a new ulcer and any existing ulcers were healed. He also emphasizes that the “overwhelming majority” of the 50 patients in the study had previously been recommended for amputation.
He says other advantages include increased independent ambulation, more stability and less pain. Furthermore, patients experienced improvements in overall physical, emotional and social function, leading to an improved quality of life, according to Dr. Grant, a Fellow of the American College of Foot and Ankle Surgeons.
However, the poster notes that surgery for Charcot is “not clearly defined” as far as indications or correct procedure selection. What questions remain to be answered? Dr. Grant says surgeons need a systematic approach that is reproducible. He notes that the study’s stepwise approach entails:
• tendo-Achilles lengthening;
• osteotomy at the Lisfrancs’ joint when indicated;
• realignment of hindfoot bones without resection;
• beaming of the columns for strength and alignment;
• platelet growth factors to enhance fusion; and
• application of an external fixator frame for compression and protection.
Dr. Grant says he first described beaming of the medial column with the use of a intramedullary placement through the first metatarsal for use in Lisfranc’s deformities and midtarsal Charcot deformities at the ACFAS conference in 1997. Several years later, Dr. Grant notes that he added locking of the lateral column along with the locking of the subtalar joint to control the torsional rotational effects that the subtalar joint has on the medial and lateral columns.

Weighing The Possible Disadvantages And Contraindications
The disadvantage to Charcot reconstruction is prolonged post-op healing, says Dr. Grant. In the study, all patients received deep vein thrombosis prophylaxis until surgeons were able to remove the external fixation devices and patients could achieve normal ambulation. Authors said the patients had touch weightbearing with a frame at six to eight weeks post-op. For two weeks after frame removal, patients wore a splint compression dressing non-weightbearing for pin site healing and edema control. Four to six weeks after frame removal, the authors say patients achieved full ambulation with an ankle foot orthotic (AFO) or a rigid custom orthotic. “In this type of patient population with multiple comorbidities, there is an increased likelihood of post-op complications such as post-op infections and dehiscence that one may see with any surgery,” says Dr. Grant.
He says these Charcot patients require follow-up visits (usually once a week) with the surgeon. Dr. Grant says another disadvantage is the return to surgery for frame or pin exchange due to a broken pin or pin tract infections.
Contraindications for Charcot reconstructions include a significant cardiac history and peripheral vascular disease, says Dr. Grant, who notes that all prospective surgical patients should have a cardiac work-up. Although most Charcot reconstructions are done with open incisions, he says the patient’s vascular status may be a contraindication. In addition, severe metabolic bone disease often accompanies Charcot foot so all patients have a bone metabolic panel preoperatively so one can address any abnormalities.


Comparing The Bone Morphology Effects Of Two Arthrodesis Methods
By Brian McCurdy, Senior Editor
A poster presented at the recent ACFAS meeting compares the effects on bone morphology of those who have undergone first tarsometatarsal joint (TMJ) arthrodesis and first metatarsophalangeal joint (MPJ) arthrodesis.
In the retrospective study, researchers reviewed 20 patients (21 feet) who had undergone first MPJ arthrodesis for forefoot pathology as well as 35 patients (39 feet) who had undergone an isolated modified Lapidus arthrodesis for forefoot pathology.
The study’s goal was to examine the structural radiographic changes of the medial longitudinal arch after arthrodesis of the first MPJ and isolated first TMJ arthrodesis. Researchers say the radiographs of all the patients showed evidence of fusion and their medical records supported clinical fusion. The authors concluded that both the MPJ arthrodesis and TMJ arthrodesis had an effect on arch morphology.
Poster co-author Graham Hamilton, DPM, says surgeons have primarily used the MPJ fusion for end-stage arthritis of the first MPJ, failed implants, avascular necrosis of the metatarsal head and failed bunion surgery. Podiatric surgeons also use the TMJ fusion for arthritis of the first TMJ and failed bunion surgery. Dr. Hamilton says the main advantage of this procedure is that it preserves the MPJ.
Aside from the effects on arch morphology, does either type of arthrodesis offer specific advantages or disadvantages? The biggest difference between the two is in convalescence, says Dr. Hamilton, the Director of Research at the Kaiser San Francisco Bay Area Foot and Ankle Residency Program. He notes that the first MPJ fusion permits immediate weightbearing. In Lapidus procedures, even though some patients have patients walk right away, he notes the standard of care is six weeks non-weightbearing.


In Brief
Merz Pharmaceuticals has been nominated for the American Business Ethics Award (ABEA), a national recognition program sponsored by the Foundation for Financial Service Professionals. The ABEA recognizes U.S. companies that exemplify high standards of ethical behavior in their everyday business conduct and in response to specific crises or challenges, says Merz.


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