Which emerging treatments show promise in treating lower-extremity wounds? Our expert panelists detail their usage of various wound care modalities, including topical antimicrobials and negative pressure wound therapy. They also take a look at what the future may bring for wound healing. Q: What new modalities do you use in the treatment of lower extremity wounds? A: When foot ulcers are complicated by impaired microcirculation and secondary infection, Steven Kravitz, DPM, uses the Circulator Boot™ (Circulator Boot Corp.) to help treat patients for whom revascularization is not a viable option. As Dr. Kravitz explains, the Circulator Boot assists distal blood supply and provides a mechanism to deliver perfusion and antibiotics to pedal and digital infected lesions. While there is no panacea in this area, Dr. Kravitz says using the device “definitely prevented” limb loss for some patients. While the boot has been around for 15 years, it has not received the exposure that he thinks it deserves. However, Dr. Kravitz believes the boot therapy may gain more statewide recognition in Pennsylvania as Medicare recently modified local carrier provisions to provide broader patient access to modalities like the Circulator Boot. Dr. Kravitz, as well as Lawrence Karlock, DPM, and David G. Armstrong, DPM, MSc, PhD, cite the benefits of Vacuum Assisted Closure therapy (VAC, KCI Inc.). Dr. Karlock uses the negative pressure wound therapy on deep draining wounds. Dr. Armstrong notes that VAC therapy simplifies deep, complex wounds. He says the VAC, along with some of the more promising acellular matrices available, such as GraftJacket (Wright Medical) and Integra (Integra Life Sciences), is “quite effective” in the subset of patients that could benefit from such treatment. For a stagnant wound that is healing slowly by conventional means, Dr. Karlock will use a living skin substitute. He believes these products can be employed earlier in the treatment of wounds. Dr. Karlock notes only 25 to 30 percent of diabetic neuropathic wounds will heal with standard care at 12 weeks. For large, non-healing wounds, Dr. Karlock has been utilizing autologous platelet rich plasma. Q: Is there any literature that supports the use of these modalities? A: Some literature reports cite positive outcomes as high as 90 percent for the Circulator Boot, according to Dr. Kravitz. In a soon to be published randomized study, Nelson indicated an average increase in perfusion of 43 percent by the end of the fourth week.1 According to Dr. Kravitz, Carlson, et. al., concluded that therapy with the boot is associated with improved outcomes in limb ulceration resulting from peripheral vascular disease. These authors indicated most patients can achieve complete ulcer healing and limb preservation.2 On the other hand, Dr. Armstrong concedes that the overall data for wound care modalities has been “exceedingly disappointing.” He attributes this to the fact that there is not much incentive for the industry to innovate. In addition, he says most wound healing dressings and devices are marketed with FDA 510k predicate approval. “Since devices or dressings only have to match up with prior approved devices, the bar is set very, very low to support their actual efficacy,” says Dr. Armstrong. “This has stifled innovation.” However, Dr. Armstrong notes that clinicians are demanding more evidence, “not just pretty pictures,” before beginning expensive therapy. He notes there are more partnerships between industry and academia for research and development. Dr. Armstrong also sees greater federal funding on the horizon as well as more promising studies. As an example, he cites the recent Lancet study, on which he was a principal author, which supports the use of negative pressure wound therapy on complex wounds.3 Such robust models will move the field forward and each randomized study brings the profession closer to standardizing research in wound care, offers Dr. Armstrong. Q: Do you have any experience with Versajet (Smith & Nephew) debridement? A: Dr. Armstrong has been using Versajet more in the OR and says it is an effective device for adjunctive debridement. However, he notes the Versajet’s per use price virtually limits the modality to use in the OR. Dr. Kravitz adds that many of his colleagues have used Versajet in the OR setting. He says it is superior to traditional sharp debridement, noting that it is quicker, stimulates wound healing and is easy to use. For outpatients, Dr. Armstrong will use ultrasound units for debridement. He has found success with Misonix and Soring devices, saying the results remind him of the results he has with maggot debridement therapy. Q: What topical antimicrobials do you employ for lower extremity wounds? A: Dr. Kravitz cites the use of various silver, cadexomer iodine and biguanide products, all of which are broad spectrum and treat resistant bacteria such as methicillin resistant Staph aureus (MRSA) and vancomycin resistant Enterococcus (VRE). He touts SilvaSorb Gel (Medline Industries), an ionic silver that delivers a sustained release. Dr. Kravitz says SilvaSorb Gel is cost effective because when one applies it with any non-adherent, the silver dressing it forms is often less expensive than many packaged dressings. For patients who have severe dermatosclerosis with deep skin fissures and skin creases, he notes the gel permits direct contact with these patients’ irregular skin surfaces. Dr. Armstrong has had promising results with silver-based antimicrobials. However, he notes every wound healing company has its own silver products. He says the silver arena has become so saturated that only the advent of meaningful clinical trials can help differentiate between the different silver modalities. Such studies are starting to emerge but Dr. Armstrong notes their scope is less than impressive. In addition, Dr. Kravitz uses the broad-spectrum XCell® Cellulose Dressings Antimicrobial with 0.3% polyhexamethylene biguanide (PHMB) (Medline Industries). He says patients with very sensitive ulcers tolerate this dressing well. Dr. Kravitz says the dressing hydrates a dry portion of a wound and absorbs exudate from another area of the same wound. For most wounds, Dr. Karlock uses mupirocin (Bactroban 2% Cream, Glaxo SmithKline) for moist wound healing, saying it does not seem to macerate as many hydrogels do. For a macerated neuropathic foot wound, he initially employs Iodosorb Gel™ (Smith & Nephew) as a topical agent. Dr. Armstrong and his group, the Center for Lower Extremity Ambulatory Research (CLEAR), are currently looking at topical and regionally-delivered antimicrobials that are “a few generations beyond silver.” Peptide-based antimicrobials and bacteriophage technologies are becoming more viable for use, according to Dr. Armstrong, who notes this month’s International Diabetic Foot Conference (www.dfcon.com ) will have a symposium about these technologies. Dr. Armstrong is a Professor of Surgery, Chair of Research and Assistant Dean at the William M. Scholl College of Podiatric Medicine at the Rosalind Franklin University of Medicine in Chicago. He is the founder and Director of CLEAR, and is an immediate past member of the National Board of Directors of the American Diabetes Association. Dr. Kravitz is a Fellow of the American College of Foot and Ankle Surgeons, and the American Professional Wound Care Association. He is an Assistant Professor in the Department of Orthopedics and is on the clinical faculty for the Advanced Wound Healing Center at the Temple University School of Podiatric Medicine. Dr. Karlock (pictured) is a Fellow of the American College of Foot and Ankle Surgeons, and practices in Austintown, Ohio. He is a member of the Editorial Advisory Board for WOUNDS, a Compendium of Clinical Research and Practice.
References 1. Nelson J. An evaluation of the efficacy of the Circulator Boot™ altering hemodynamics of the ischemic lower extremity and foot. 2. Vela A, Carlson LA, Blier B, Felty C, Kuiper JD and Rooke TW. Circulator boot therapy alters the natural history of ischemic limb ulceration. Vascular Medicine 5:21-25, 2000. 3. Armstrong D, Lavery L. Negative pressure wound therapy after partial diabetic foot amputation: a multicenter, randomized controlled trial. Lancet 366:1704-1710, 2005.