Aerosol method stretches skin grafts

East Grinstead, England - Researchers here have embarked on the first multicenter study to evaluate the efficacy of a spray-on skin technique in treating severe burns.

The procedure involves spraying cultured skin cells over a widely meshed skin graft, a method researchers say covers a broader area more quickly and effectively than traditional skin grafting.

A second study involving spray-on skin for the treatment of young children suffering partial-thickness scald injuries is also under way at the Blond McIndoe Centre, together with surgeons from burn centers at Queen Victoria Hospital (QVH), East Grinstead and the Royal Victoria Infirmary (RVI), Newcastle. Researchers hope this study demonstrates the ability of the spray-on cells to prevent long-term hypertrophic scarring, a life sentence of further reconstructive surgery for these unfortunate children, according to S. Elizabeth James, Ph.D., head of research, wound healing and tissue reconstruction at the Blond McIndoe Centre.

At press time, researchers at the Blond McIndoe Centre and surgeons at the QVH had recruited approximately a half dozen adult patients of a projected 20 to 25 total and, with surgeons at the RVI, five children of a projected 50 for the pediatric scald study.

Unfortunately, two of the treated adult patients suffered burns so severe they died before doctors could collect long-term follow-up data, as did another elderly patient who died after leaving the hospital, reports Baljit Dheansa, F.R.C.S., M.Sc., F.R.C.S.(Plast), a consultant burns physician and plastic surgeon at QVH.

"We're still in the early stages," he says. "But prior to setting up the trial, we'd used this approach on five or six patients and had good results."

Even in the best hands, he says, patients with burns covering 50 percent to 60 percent of their skin will require skin-graft harvesting from healthy sites three or four times. Creating a lattice-like mesh from harvested skin can stretch grafts over a wider area, but it leaves holes that take quite a while to fill in, Dr. Dheansa says.

In contrast, he says, the hospital's approach uses skin mesh with holes that allow it to cover between four and six times its original surface area (versus two or three times with conventional meshing) coupled with cultured skin grown at the Blond McIndoe Centre, an independent medical research charity solely dependent on public donations.

Protocol

First, surgeons remove patients' burned tissue and temporarily cover the affected areas with donated cadaveric skin to protect wounds.

"In the meantime, we take a small sample of skin and grow it in the lab such that we get millions and millions of cells growing over a two-week period," Dr. Dheansa explains.

At that point, surgeons harvest as much of the patient's normal skin as possible, mesh it and apply it to the burn wound. To help the holes fill in faster, scientists harvest the cultured cells in large numbers and spray them over the graft using a standard syringe with an aerosol attachment before applying dressings.

Without the cultured cells, it took two or three weeks for gaps within patients' skin mesh to fill. With them, it takes about 10 days, Dr. Dheansa says.

"Because we can use a wider meshed pattern," he adds, "it means we can harvest patients' skin less often. And we're actually giving patients back more than they started with" through the addition of cultured cells. With this approach, Dr. Dheansa says, a graft that starts out measuring 2 cm can cover the lateral half of a patient's trunk in about two weeks.

'Brilliant idea'

Spray-on skin is "a brilliant idea," says Vic Narurkar, M.D., a San Francisco-based private practitioner, assistant clinical professor of dermatology at the University of California, Davis, Medical Center and president-elect of the American Society of Cosmetic Dermatology and Aesthetic Surgery (ASCDAS).