Current Concepts With Bioengineered Alternative Tissues

Jason R. Hanft, DPM, FACFAS, and Maribel Henao, DPM

Living and non-living skin equivalents can be valuable adjunctive treatments for chronic lower extremity wounds. Accordingly, these authors review the current literature, discuss the role of advanced therapies in facilitating wound closure and provide pertinent case studies.

The management of chronic non-healing ulcerations continues to be a challenge for healthcare practitioners today. Not only can ulcers eventually lead to serious complications such as infection and amputation, they also affect the quality of life and bring about a significant economic burden.

   Foot ulcers develop in approximately 15 percent of patients with diabetes with an incidence of nearly 2 percent per year.1-3 Ultimately, 14 to 20 percent of patients with a diabetic foot ulcer will require an amputation of the affected limb with nearly 85 percent of lower limb amputations preceded by a foot ulcer.1,2,4,5

   Lower extremity ulcers can be caused by ischemia, neuropathy, pressure and venous hypertension. Regardless of the etiology, recalcitrant ulcers cause significant morbidity and mortality.6 The increased rate of mortality in diabetic patients with a foot ulcer has been well documented.

   A prospective, population-based study followed 155 diabetic patients with a history of a foot ulcer, 1,339 diabetic patients without a history of a foot ulcer and 63,632 non-diabetic patients for 10 years in Norway.6 Researchers found that 49 percent of diabetic patients with a history of a foot ulcer died within that 10-year follow-up period. Only 35.2 percent of diabetic patients without a history of a foot ulcer and 10.5 percent of non-diabetics died. The study demonstrated that having diabetes and a history of a foot ulcer was associated with more than a twofold risk of mortality in comparison to that of non-diabetic patients.

   Another prospective, population-based cohort study included adults with type 1 and type 2 diabetes mellitus presenting with their first foot ulcer.7 Researchers found a threefold increased risk of mortality in diabetic patients with moderate ischemia or peripheral arterial disease (PAD), and a threefold increased risk of recurrent ulceration in those study patients with one or more microvascular complications.

   Similarly, venous leg ulcers affect up to 2.5 million patients per year with a prevalence rate ranging from 0.06 to 2 percent.8,9 Eighty percent of leg ulcers result from venous disease, which is more common with increasing age.9 Arterial disease accounts for 10 to 25 percent of venous leg ulcers, possibly coexisting with venous disease.9

   In addition to the high incidence of venous ulcers, there is an increased recurrence rate with venous ulcers. The recurrence rate is reportedly as high as 72 percent in treated patients.9,10 Venous leg ulcers cause significant morbidity, impaired mobility and social isolation with substantial costs to all healthcare systems.11

A Closer Look At The Wound Healing Society Guidelines

In 2006, the Wound Healing Society selected a panel of advisers to develop guidelines for the treatment of lower extremity diabetic ulcers based on the evidence.12 The panel formulated guidelines in eight categories and also listed the strength of evidence supporting each guideline as Level I, Level II or Level III.

   Level I is evidence based on meta-analysis of multiple randomized controlled trials or at least two randomized controlled clinical trials that support the intervention of the guideline.12 Level II is evidence based on at least one randomized controlled trial and at least two significant clinical series. Level III is evidence based on suggestive data of proof of principle but lacking any Level I or Level II evidence.

   Ideal wound management should include proper diagnosis, verification of blood supply, debridement, infection control and offloading.12 The ultimate goal in the treatment of wounds is complete closure although increasing the rate of healing is equally as important. Expeditious wound closure not only improves the quality of life and decreases costs, but also helps to lessen the chances of complications such as infections and amputations.

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