Exploring The Potential Of Bioengineered Alternative Tissues

Clinical Editor: Lawrence Karlock, DPM

Bioengineered alternative tissues, or skin substitutes, can lead to success in patients with wounds that have not responded well to other modalities. Accordingly, our expert panelists offer a closer look at where these products fit into the wound healing armamentarium and share pertinent pearls from their clinical experience with these products. Q: What skin substitutes do you utilize in treating lower extremity wounds? A: Paul Kim, DPM, has had success using Apligraf® (Organogenesis) for more superficial chronic wounds. He cautions practitioners that it may take multiple applications of Apligraf to convert a chronic wound to an acute wound. Apligraf works well at stimulating granulation tissue, according to Dr. Kim. He adds that sometimes wounds treated with Apligraf attain complete closure without the need for a split-thickness skin graft (STSG). Dr. Kim finds Integra® (Integra Life Sciences) works well in deeper wounds and decreases the overall wound depth. He uses it to build up the floor of the wound and notes he may follow up by applying Apligraf. As Dr. Kim states, the conjunctive use of negative pressure wound therapy also appears to speed up the wound healing process. Michael Miller, DO, has used Apligraf and Oasis (Healthpoint) in his outpatient practice with “excellent” results. He participated in Oasis trials and found success in using the product to help treat venous and diabetic ulcers. Dr. Miller has also used Dermagraft (Advanced Biohealing) to facilitate healing in difficult wounds. John S. Steinberg, DPM, prefers the term “bioengineered alternative tissues” (BATs) to “skin substitutes,” which he feels can be “very misleading.” He often uses Apligraf and Integra in the OR and the clinic setting. Dr. Steinberg is just starting to have experience with Graft Jacket (Wright Medical). Q: What products do you prefer for a plantar neuropathic diabetic ulcer and why? A: Dr. Steinberg describes this as “a loaded question,” saying the true variable is the depth of the wound and not the anatomic location. He uses Integra for deeper wounds that require regeneration of deep soft tissue layers. Dr. Steinberg uses Apligraf for more superficial wounds in order to facilitate epidermal growth and closure. The key to healing plantar wounds does not depend on the product that one utilizes, according to Dr. Kim. Rather, he says the most important concept is offloading. As Dr. Kim notes, one needs to accommodate or surgically remove/reconstruct the offending bony prominence. “Without dealing with the underlying focal pressure, all BAT products will fail eventually,” claims Dr. Kim. When it comes to plantar neuropathic diabetic ulcers, Dr. Miller cites Regranex, Promogran and Promogran Prisma (Johnson and Johnson) as effective. He applies Apligraf to non-infected, mostly granular wounds. Dr. Miller notes the product forms epithelial tissue quickly and fills the wound depth. He says one can apply GraftJacket to deeper, necrotic wounds with bone or tendon involvement. The product seals the wound from the outside environment and also incorporates into the tendon, decreasing the potential for tendon loss, according to Dr. Miller. Dr. Miller also uses PriMatrix (TEI Biosciences), a new acellular collagen dermal tissue matrix derived from fetal bovine skin. As he explains, the body can remodel the matrix into a functional tissue and the product becomes easily vascularized. “My goal is to promote healing through improved patient compliance by making the treatments as simple and involving as little patient manipulation as possible,” says Dr. Miller. Q: Do you ever utilize split-thickness or full-thickness skin grafts on the plantar foot? A: To cover defects on weightbearing areas, one can use a well-designed rotational or transpositional flap, according to Dr. Kim. He recommends designing the flap in such a fashion so it is derived from a non-weightbearing area. Dr. Kim says one can use a STSG to graft the area vacated by the flap. By using such a technique, Dr. Kim says he has not had to use a full-thickness graft. Dr. Steinberg uses both types of grafts. He says clinicians may now use bioengineered alternative tissues and VAC therapy (KCI) to regenerate the plantar soft tissue layers first and then apply a glabrous STSG. “We perform drastically fewer free flaps using this approach,” notes Dr. Steinberg. On the other hand, Dr.

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