A Closer Look At Bioengineered Alternative Tissues
The medical management of wounds today is vastly different than wound management was a few years ago. Evidence-based research has provided the practitioner with new technologies that can predictably heal wounds that previously would have threatened limb loss.
The team approach to complex wound management has been widely embraced and many communities now have referral centers and hospital-based teams that provide multidisciplinary care. With an estimated 20.8 million people in the United States now affected by diabetes and a 15 percent lifetime incidence of foot ulceration in those diagnosed with diabetes, the public health impact of wound care is rapidly making its way into the spotlight. One can properly assume these concerns have a significant impact on the projection that Medicare is expected to be insolvent by the year 2018.
Recent advances in bioengineering have expanded the wound care treatment armamentarium with products that can stimulate healing where there was once a chronic or problem wound. However, the complexity and sheer number of bioengineered products now available for wounds has led to some confusion and hesitancy on the part of many physicians who contemplate their use. Clearly, there is no one perfect bioengineered product for all wounds. Accordingly, let us take a closer look at the current leading biotechnologies that clinicians may utilize for lower extremity wounds.
Redefining ‘Skin Substitutes’ With New Terminology
A key point of confusion in the arena of new wound technologies begins with the labeling and terminology used to describe these products. Some terms that are commonly used include “bioengineered skin,” “bioengineered skin substitutes,” “biological skin substitutes,” “tissue-engineered skin” and “bioengineered skin equivalents.”1-9 The term “skin” generally does not apply because many of these products have no dermal or epidermal components. The term “equivalent” is especially erroneous because these products are not equivalent to skin and should not be used in such a manner.
The inconsistent, intermingled and sometimes arbitrary use of these terms has led to some difficulty. We believe these terms do not fully or accurately describe these products, and the role they play in wound closure.
Therefore, we propose a new term that more appropriately describes this group of products: “bioengineered alternative tissue” (BAT). We use the term “bioengineered” because these products have been produced artificially or modified in some way that alters the biology and its interaction with the wound bed. In many cases, bioengineered products are processed in such a way and infused with ingredients to optimize their ability to stimulate a positive wound healing wound environment when one places them into the clinical site. “Alternative” better delineates the difference between an autologous skin graft and the manufactured/engineered biologic products. We believe the term BAT more accurately encompasses and describes these wound care products, and would help direct their use in the correct types of wounds.
The overall goal in using any of these products is the central concept of converting a chronic wound into an acute wound (also see “Key Fundamentals For Successful Outcomes With BAT Products” at left). A chronic wound is a wound that does not heal or is retarded in healing and generally populated with senescent cells. Most often, one would determine whether a wound has become chronic through the clinical assessment of wound quality and through serial wound measurements. Some published criteria cite that a wound should have a 10 to 15 percent decrease in area each week or have a greater than 50 percent decrease over the period of one month.10