Living tissue graft aids wound healing

Some medical topics are not for the faint of heart or those with a weaker stomach. One obvious example is that of chronic wounds and their care. As a specialist in foot and ankle medicine, I find this a fascinating topic which occupies a fair amount of my attention. Although not everyone’s cup of tea, wound care is challenging. An extremely common concern, these non-healing sores (technically known as ulcers), are not only a common problem but often very difficult to resolve. Numerous physicians, in a variety of specialties, encounter them in the course of their work. Thus, some healthcare providers practice some degree of wound care. Unfortunately, because it is not their specialty, they may use out of date, unproven, or ineffective methods and principles.

Because people are living longer, these resistant lesions are more frequently encountered in the general population, especially with the continued increase in the incidence of diabetes. But wound care has advanced tremendously over the years. Evidenced-based medical research has expanded our armamentarium, our available treatment options. Consequently, we know how to manage wounds vastly better now than a few years ago.

Recognition of the scope of this problem has led to abundant research and, consequently, the development and release of a slew of new products, medicines, technique and technologies. Wound care once consisted of the application of sterile water, the antiquated wet-to-dry technique. This is no longer considered the standard of care. The failure of “wet-to-dry” boils down to the fact wounds should not be allowed to dry out. Obviously, a piece of wet gauze will stay moist for only so long. Also important, a greater risk of infection and an impractical application schedule

A listing of the many developments and discoveries in this field is not possible in the space of this treatise, but one of the most notable advances is that of the “bioengineered alternative tissues”. Recent advances in bioengineering have led to a whole new family of products that demonstrate biological activity, stimulating healing in a way we have never been able to do before. B.A.T., the acronym for this concept, involves the production and application of living tissue, or at least, substances with biologic activity. This is a diverse group, with examples including material grown in the lab, skin from a cadaver, or placental tissue from a (planned) Cesarean section. A general theme here is providing some of the critical materials, cells included, required for healing.

The sheer volume of products designated and appropriate for ulcers of the skin is staggering. Literally every day, new products go on the market. Naturally, they can be categorized into specific categories, like those best for a wound which produces excessive drainage, or one which is too dry. Numerous agents are intended to fight infection, a huge problem when an open sore is present. (Intact skin is a wonderful barrier to bacteria, but that obstacle is lost when a non-healing ulcer is present.)

With roughly 30 million people afflicted with diabetes in the US, and an incidence of foot ulcers at 15 percent of these individuals, the financial ramifications to our health care system cannot be downplayed. About one fourth of all diabetes-related hospital admissions are due to a foot ulcer. A foot ulcer precedes a diabetic amputation about 15 percent of the time. A skin ulcer is a challenging condition, and is by no means a temporary or easily resolved one. So a technology that promises to provide faster, more complete closure of these problems is of tremendous interest. The studies to date have been sufficiently positive to warrant coverage for these BAT products as a covered service by Medicare and most private insurances.

Even with some of these new advanced biologically-active grafting materials, the basics of good wound care remain essential. These include providing a moist wound environment, reducing excess (weight bearing) pressure, restoring adequate blood flow (an absolute necessity for healing anything), and regular removal of tissue that isn’t viable (via debridement, aka surgical trimming). Prevention of infection is also critical, or treatment if one has occurred. Many non-healing skin ulcers will close eventually utilizing these well-accepted and appropriate techniques.

“Bioengineered alternative tissues” is the most accepted label for this class of wound care products, although there have been many. These typically provide growth factors to the wound, promoting the formation of new, healthy tissue, as well as providing an optimal wound environment. These are quite different from a skin graft, in which a piece of skin is harvested from somewhere else on the body and used to “patch” the opening. This is a tried and true method, with many successful cases performed, but obviously includes some negatives.

Current standards state these advanced products are appropriate and, in fact, recommended if wound measurements reveal less than 50 percent reduction in size over a one month period. Of course, these are guidelines and many factors come into play, with cost being just one of them. Still, we know the longer these resistant lesions remain open, the greater the risk of complications, with infection perhaps being the most significant.

Many different bioengineered tissue products have been developed. Generally, they can be divided into two categories: those that provide living tissue or those that function as a scaffold, supporting the ingrowth of cells. Products from this latter category tend to be reserved for deeper wounds in which the deeper tissues have been compromised but they do not contain living cells. Since the base of the ulceration needs to be built up, a supportive scaffold is desirable and these products do that. The products that provide living tissue, those from the former category, either stimulate the release of growth factors or deliver them directly to the wound. Growth factors are often considered the “holy grail” of wound care, the magic ingredient for wound closure.

There is a time and place for these advanced, biologic grafting materials but they are not needed for every wound. An experienced specialist will be knowledgeable about the various types of wound care product and techniques. Yet they need to recognize when standard treatment modalities are not doing enough. Earlier identification of the causative agents is critical, with many often at play (eg. artery disease, diabetes, obesity, inactivity, poor nutrition). But when needed, the use of BAT’s for these non-healing ulcerations may lead to quicker healing times.

While there is a multitude of options for the care of these difficult problems, one must be discerning about what and when they are selecting a technique or a product. The characteristics and limitations of these and all the other many different dressings, medicines, and wound treatments must be familiar to the treating provider, so they can make educated choices. With the proper choices, the chances of obtaining a favorable result, closure, are significantly increased. That means a whole better quality of life. Perhaps more important, it means a longer, better lifespan. And that’s good medicine.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments atdrcmclean@outlook.com.