Tag Archives: skin grafting

Better Skin Grafts – take only one layer

Research shows that a skin-graft harvesting system aids chronic wound recovery and reduces care costs by accelerating the healing process.

More than six million cases of chronic wounds cost $20 billion each year in the United States. Diabetic ulcers, pressure sores, surgical site wounds, and traumatic injuries to high-risk patients account for most wounds that won’t heal. Continue reading »

Skin substitutes: Understanding product differences

Skin substitutes (also called tissuebased products and dermal replacements) are a boon to chronic wound management when traditional therapies have failed. When selecting skin substitutes for their formularies, wound care professionals have many product options—and many decisions to make.

Repair of skin defects has been a pressing concern for centuries. As early as the 15th century BC, Egyptian physicians chronicled procedures and herbal treatments to heal wounds, including xenografts (skin from another species). The practice of applying allografts (human cadaver skin) to wounds was first documented in 1503. In 1871, autologous skin grafting (skin harvested from the the person with the wound) was tried. Next came epithelial- cell seeding, which involves scraping off the superficial epithelium of healthy skin and transplanting the cells onto the wound.

Today, skin grafting and seeding techniques are used successfully for treating wounds. Autologous grafts are the optimal choice for wound coverage. But availability of skin for harvesting may be limited, particularly in cases of large burns. Also, autograft procedures are invasive and painful.

Allografts and xenografts (for instance, porcine or bovine grafts) may be used as temporary skin replacements. Typically, though, these are later covered by an autograft. Also, they have significant clinical limitations, including immune rejection with allogeneic grafts (grafts from donors who are genetically different from the recipient but of the same species), as well as pain, scarring, slow healing, and infection.

Bioengineered skin substitutes

Bioengineered skin substitutes were created to eliminate certain problems with skin grafts. They’re used to treat non-healing wounds and for soft-tissue grafts in patients with life-threatening full-thickness (third-degree) or deep partialthickness (second-degree) burns, surgical wounds, diabetic foot  ulcers, venous ulcers, and certain other conditions, including epidermolysis bullosa. (See Skin substitutes for chronic wounds.)

Bioengineered skin substitutes contain live human cells that are seeded onto a matrix and provided with the proteins and growth factors needed to grow and multiply into the desired tissue. Various biosynthetic and tissue-engineered human skin equivalents are manufactured under an array of trade names and marketed for various purposes. Because these products are procured, produced, manufactured, or processed in different ways, they can’t be evaluated as equivalent.

Bioengineered skin substitutes fall into five classifications:

cultured epithelial autografts

human skin allografts derived from donated human cadaver tissue

allogenic matrices derived from human neonatal fibroblasts

composite matrices derived from human keratinocytes, fibroblasts, and bovine or porcine collagen

acellular matrices derived from porcine or bovine collagen.

Some skin substitutes also possess unique regenerative properties. For instance, an allograft made of amniotic membrane and umbilical cord (NEOX®, made by Amniox Medical) exhibits the same biology responsible for propagating fetal regenerative and scarless wound healing. When transplanted into the adult wound environment, these placental tissues modulate inflammation and promote healing.

In a 2016 study of 32 diabetic foot ulcers by Raphael, an average of 1.68 NEOX applications resulted in a healing rate of 87.5%. A 2016 study by Caputo et al found that an amniotic membrane/umbilical cord allograft proved effective in treating complex diabetic foot ulcers with osteomyelitis; patients had a 78.8% healing rate after an average of 1.2 applications. In contrast, a 2002 study by Margolis et al found that only 32% of diabetic foot ulcers healed within 20 weeks of standard-of-care therapy (debridement, dressings, and topical ointment).

Choosing skin substitutes

Efficacy of skin substitutes varies widely in terms of the number of applications needed to close a wound, healing rates, and healing times. Dehydrated amniotic skin substitutes are convenient to store and use, but are less potent than cryopreserved amniotic/umbilical cord skin substitutes, which better preserve the structure and key biological signaling of fetal tissues to quickly promote revascularization in the adult wound bed. Choosing the skin substitute to match the desired clinical outcome is crucial. In addition, Medicare coverage varies considerably by region. (See How Medicare reimburses for skin substitutes.)

Ease of use and storage

Some skin substitutes require more maintenance than others, potentially leading to product waste if storage conditions aren’t  optimal. For example, tissue-based products containing live cells have stringent shipping and application requirements; they’re shipped on dry ice and the patient must receive the graft within hours after the product arrives at the wound center. During an ice storm in Dallas, a truck delivering a tissuebased skin substitute for one of our patients had to wait out the storm on the side of the road; the patient cancelled his appointment due to impassable roads. By the time the patient rescheduled and the truck arrived with the skin substitute, the product was no longer usable and had to be thrown out.

In contrast, a skin substitute that remains stable in a wound center’s refrigeration unit is available when the patient needs it, so treatment can start sooner than with a product that has a narrow window for use. For instance, NEOX can be refrigerated safely at temperatures ranging from -112° to 39° F (-80° to 3.8° C) for up to 2 years without structural or functional compromise. If the product isn’t opened, it can be exposed to room temperatures of 68° to 77° F (20° to 25° C) for up to 6 hours and safely returned to cold storage. NEOX is the only cryopreserved amniotic membrane product that doesn’t need to be stored in a deep freezer.

Also, skin substitutes that require extensive preparation consume precious staff resources. One product, for example, needs to be washed in water at a temperature not exceeding 43° F (6.1 °C) before it can be applied to a patient’s wound. This requires an extraordinary effort for personnel in a busy wound clinic. Skin substitutes that can be exposed to room temperature before use are much more convenient and eliminate the need for special equipment, such as thawing tubs.

Disadvantages of skin substitutes

As an advanced tissue treatment modality, skin substitutes are more expensive than conventional wound dressings and may have more complex storage and preparation requirements. To prevent waste, clinicians should choose a product that can be stocked in a range of sizes. Some substitutes are available only in small or very large sizes, which don’t conform to most wounds; this means the wound center ends up paying for the excess product it must throw away.

Also consider how many times a skin substitute will need to be placed on a patient’s wound before it closes. One that needs to be applied only twice is more cost effective than a less expensive one that requires multiple applications. n

Myra Varnado is director of Clinical Wound and Ostomy Services for Corstrata, a national telemedicine company in Savannah, Georgia. Since 2000, she has been a member of the Wound Guidelines Task Force for the Wound, Ostomy and Continence Nurses Society (WOCN). Varnado is a primary author of WOCN’s guideline for management of wounds in patients with lower-extremity neuropathic disease. She is also a speaker and consultant for Amniox Medical, Inc., which markets the NEOX line of products.

Selected references

Amin N, Doupis J. Diabetic foot disease: from the evaluation of the “foot at risk” to the novel diabetic ulcer treatment modalities. World J Diabetes. 2016;7(7):153-64.

Calota DR, Nitescu C, Florescu IP, et al. Surgical management of extensive burns treatment using allografts. J Med Life. 2012;5(4):486-90.

Caputo WJ, Vaquero C, Monterosa, A et al. A retrospective study of cryopreserved umbilical cord as an adjunctive therapy to promote the healing of chronic, complex foot ulcers with underlying osteomyelitis. Wound Repair Regen. 2016;24(5):885-93.

Cooke M, Tan EK, Mandrycky C, et al. Comparison of cryopreserved amniotic membrane and umbilical cord tissue with dehydrated amniotic membrane/ chorion tissue. J Wound Care. 2014;23(10):465-74, 476.

Doughty DB, McNichol LL, eds. Wound, Ostomy and Continence Nurses Society® Core Curriculum: Wound Management. Philadelphia, PA: Wound, Ostomy and Continence Nurses Society; 2015.

Halim AS, Khoo TL, Mohd, et al. Biologic and synthetic skin substitutes: an overview. Indian J Plast Surg. 2010;43(Suppl):S23-8.

Hill-Rom. 2016 International Pressure Ulcer Prevalence (IPUP) Survey. 2016.

Margolis DJ, Allen-Taylor L, Hoffstad O, et al. Diabetic neuropathic foot ulcers. Diabetes Care. 2002; 25(10):1835-9.

Nathoo R, Howe N, Cohen G. Skin substitutes: an overview of the key players in wound management. J Clin Aesthet Dermatol. 2014;7(10):44-8.

National Pressure Ulcer Advisory Panel. NPUAP Pressure Injury Stages. 2016.

Raphael A. A single-centre, retrospective study of cryopreserved umbilical cord/amniotic membrane tissue for the treatment of diabetic foot ulcers. Wound Care. 2016;25(Suppl 7):S10-7.

Clinical Notes—May/June 2016

Moldable skin barrier effective for elderly patients with ostomy

A study in Gastroenterology Nursing reports that compared to a conventional skin barrier, a moldable skin barrier significantly improves self-care satisfaction scores in elderly patients who have a stoma. The moldable skin barrier also caused less irritant dermatitis and the costs for leakage-proof cream were lower.

The application of a moldable skin barrier in the self-care of elderly ostomy patients” included 104 patients ages 65 to 79 who had a colostomy because of colorectal cancer.

Risk factors for severe hypoglycemia in older adults with diabetes identified

Risk factors associated with severe hypoglycemia in older adults with Type 1 diabetes” include glucose variability and greater lack of awareness of hypoglycemia.

Participants in the case-control, multi-center study, published in Diabetes Care, were age 60 or older and had a history of diabetes dating back 20 years or more.

Thermal imaging via smartphone helps detect inflammation

Early detection of inflammation in wounds promotes early treatment, and clinicians may have an additional assessment tool available to them. A recent study published in the Journal of Wound Care concludes the FLIR ONE, a thermography device that connects to a smartphone, can be successfully used to assess subclinical inflammation in patients with pressure ulcers and diabetic foot in clinical settings.

Use of smartphone attached mobile thermography assessing subclinical inflammation: A pilot study” included 16 thermal images from eight patients and found good criterion-related validity and inter-rater reliability when the FLIR ONE results were compared to those from a handheld device. The findings may open the door to more thermal imaging assessment at the bedside.

Role of skin substitutes in treatment of diabetic foot ulcers analyzed

Systematic review and meta-analysis of skin substitutes in the treatment of diabetic foot ulcers,” published in Wound Repair and Regeneration, concludes that skin substitutes “can, in addition to standard care, increase the likelihood of achieving complete ulcer closure compared with standard care alone in the treatment of diabetic foot ulcer.”

The authors caution, however, that long-term effectiveness, including limb salvage and recurrence, is not known, and cost-effectiveness is not clear. The review included 17 randomized clinical trials, with a total of 1,655 patients.

Tap water safe alternative for wound cleaning

“Tap water is a safe alternative to sterile normal saline for wound cleansing in a community setting,” concludes a study in the Journal of Wound, Ostomy and Continence Nursing.

Tap water versus sterile normal saline in wound swabbing: A double-blind randomized controlled trial” studied 22 people with 30 wounds. Half were in the tap water group and half in the sterile normal saline group. Researchers found no differences in the proportion of wound infection and healing between the two groups.

Review of skin grafting in patients with chronic leg ulcers

Autologous split-thickness skin grafting remains the gold standard in terms of safety and efficacy for chronic leg ulcers, according to a review article in International Wound Journal.

Skin grafting for the treatment of chronic leg ulcers—a systematic review in evidencebased medicine” also found that skin grafts are more successful in patients who have chronic venous leg ulcers, compared to other types. The researchers noted that skin tissue engineering is “rapidly expanding” and holds promise for better outcomes when treating patients with long-lasting chronic wounds.

C difficile may be risk factor for pouch failure after reconstruction

Patients with a history of preoperative Clostridium difficile colitis may be at higher risk for pouch failure after ileal pouchanal anastomosis reconstruction following total proctocolectomy for ulcerative colitis, according to a study in Inflammatory Bowel Disease.

The authors of “Clostridium difficile infection in ulcerative colitis: Can alteration of  the gut-associated microbiome contribute to pouch failure?” defined pouch failure as permanent ostomy diversion or pouch excision. Of 417 patients in the study, 28 (6.7%) developed pouch failure.

Lymphedema education lacking

Researchers of a study in the Journal of Cancer Education report that only 19.9% of 180 women with lymphedema after breast cancer surgery reported they had received education or information about the condition postoperatively.

The importance of awareness and education in patients with breast cancer-related lymphedema” also reports that, “The degree and duration of lymphedema were lower in patients who had been informed or educated about lymphedema as compared to the patients who had not been informed or educated, but the difference was not statistically significant.”

Color charts help improve pressure ulcer risk assessment

Use of Munsell color charts to measure skin tone objectively in nursing home residents at risk for pressure ulcer development,” published in the Journal of Advanced Nursingconcludes that the color charts provide a “more objective measurement of skin tone than demographic categories.”

The researchers state that use of the charts can improve pressure ulcer risk assessment when current clinical guidelines are less effective.