The ultimate goal of wound care is to accelerate healing and prevent acute wounds from becoming chronic. Part of this process involves choosing a wound dressing that complements the characteristics of the wound.
The $6.6-billion market for advanced wound dressings offers dozens of variations. Both alginate dressings, composed of seaweed or kelp, and foam dressings, made of polymer solutions, can absorb exudate and keep wounds moist; collagen or silicone-based dressings help stimulate new tissue and blood vessel growth; and hydrogels and hydrocolloids allow wounds to retain moisture (Front Bioeng Biotechnol 2020. doi:10.3389/fbioe.2020.00182).
Each category of dressing may contain additional substances—calcium, honey or silver, for example—to enhance antimicrobial activity (Cellulose 2020;27:385-400. doi.org/ 10.1007/ s10570-019-02795-1). Given the array of possibilities, how do experts choose the best option for each patient?
“In an ideal world, the wound dressing literature would help us choose among the many products, but unfortunately, we have minimal evidence to support the use of one product over another,” said Alex Wong, MD, the chief of plastic surgery at City of Hope Comprehensive Cancer Center, just outside Los Angeles.
High-quality trials comparing the efficacy of different wound dressings are hard to come by. According to a 2014 review that examined the effectiveness of wound dressings, experts found the literature contained “much conflicting data,” with few randomized controlled trials clearly demonstrating the advantage of particular materials or categories of wound dressings (Adv Wound Care [New Rochelle] 2014;3:511-529).
Although the literature provides few definitive answers, “no wound or patient is the same,” and thus no single wound dressing will provide a “magic bullet” for everyone, Dr. Wong said.
Like dressings, wounds come in many forms (venous skin and diabetic foot ulcers, pressure sores, radiation-related injuries, or burns), with a range of characteristics (necrotic or infected tissue, exposed bone, or excessive exudate). Patient factors, including diabetes, peripheral artery disease, cancer and smoking, also affect wound healing.
“I can purchase all of the most expensive wound dressings out there, but they won’t help if I don’t know the patient factors contributing to poor wound healing,” said Jeffrey Chang, MD, MS, an assistant clinical professor in the Division of Plastic Surgery at City of Hope. “You have to understand and treat both.”
That’s why Dr. Chang begins each visit with a thorough patient exam and history: Does the patient have diabetes or hypertension? Does he have a condition that suppresses his immune system?
After identifying patient risk factors, Dr. Chang focuses on the wound itself, relying on four fundamental principles of wound care to guide his decision making. These principles, developed almost two decades ago, are represented by the acronym TIME:
When examining the wound, he looks for dead or infected tissue, moisture content, and how far apart the wound edges are.
For infected wounds, Dr. Chang may prefer a dressing with antimicrobial properties. If a wound is too wet, he will opt for a product that can absorb excess exudate. If the edges are far apart, he will use a leg wrap or abdominal binder to help close the wound. “By going through these stages, I can navigate my way to a more optimal dressing,” Dr. Chang noted.
Jennifer Powers, MD, an associate professor of dermatology at the University of Iowa Carver College of Medicine, in Iowa City, uses a similar process to determine the most appropriate dressing. “I don’t just zoom in on the wound; I analyze my patient from head to toe to understand the multifactorial reasons for poor healing,” she said. “I look at the skin over the entire body, I do blood work to assess kidney and liver function, as well as other factors, that may cause a wound to fester.”
The wound itself can point Dr. Powers toward a particular type of dressing. “I’ve had patients walk into my clinic with a diaper taped to their leg because of the exudate coming off the wound,” she said. In this case, Dr. Powers would likely go for an alginate or foam dressing to help manage the exudate.
The question then becomes which variation of alginate or foam dressing is optimal. Alginate dressings, for instance, have dozens of spinoffs—some embedded with silver, others with calcium or zinc calcium.
Fortunately, experts do not need to sort through dozens of options. Wound dressing choice is often driven by a hospital’s formulary, which will vary from institution to institution.
“Most hospitals will have one to two options in any given class of products because stocking much more than that will be a big financial loss for an institution,” said Geoffrey Gurtner, MD, a professor of surgery and the inaugural vice chairman of surgery for innovation at Stanford University School of Medicine, in California. “I just use whatever wound dressings are available among those options.”
Dr. Wong agreed that staying flexible with wound dressing choice is important. “Your hospital may not be willing or able to purchase a specific wound dressing for you, which is why I do not rely on any product in particular,” he said.
When choosing among an institution’s offerings, personal experience and cost also may influence decision making. To avoid surgery, Ernest S. Chiu, MD, a plastic and reconstructive surgeon at NYU Langone Health, in New York City, often uses skin substitutes to treat chronic, slow-healing wounds, but he questions whether the potential to accelerate wound healing by a few days justifies the higher price tag of these products. Skin substitutes can cost hundreds, even thousands of dollars, but it’s not clear whether these products are cost-effective (Adv Wound Care [New Rochelle] 2014;3:511-529).
The challenge for the wound care industry will be to veer away from developing more “me-too” products with slight variations and instead focus on pushing the boundaries of wound care. Dr. Chiu highlighted early work that uses artificial intelligence–based predictive algorithms to help clinicians make diagnoses and predictions about the wound healing process (JAMA Netw Open 2021;4:e217234).
Dr. Chang sees promise in biologic dressings. A recent systematic review of 25 studies found that diabetic foot ulcers treated with biologic skin substitutes were 1.67 times more likely to heal by 12 weeks compared with standard-of-care dressings (Ann Plast Surg 2019;83[4S suppl 1]:S31-S44).
Other experts are investigating the use of stem cells in wound care. Although the evidence to date focuses on animal models, combining hydrogel dressings with adipose-derived stem cells, for instance, could help accelerate the healing process (J Biomed Mater Res B Appl Biomater 2019;107:278-285).
“It’s still early days but I think we’re heading more toward biologic-based wound dressings embedded with growth factors that can help jump-start the wound healing process as well as understanding the molecular basis of a wound in order to optimize the treatment,” Dr. Chang said.
However, Dr. Chang added, “even without wound dressing products, as long as the TIME principles are followed—no dead tissue, no infection, moist environment—the body will heal. Having advanced wound dressings in our tool box helps but means we need to find the right balance between a product that is appropriate and a cost that is reasonable.”