Skin transplants

REPAIRING the skin of those who have been burned is a process of autotransplantation. First, the surgeon removes the scorched tissue from the affected area. Then he takes a patch of healthy skin from elsewhere on the patient’s body, stretches it to fit the affected area and, that done, fixes it to the wound with sutures, staples or glue. In the hands of a skilled operator such grafts are nearly always successful, but the process could surely be improved on.

That, at least, is the view of Jörg Gerlach of the University of Pittsburgh. And he—and, working separately, Fiona Wood, a plastic surgeon based in Perth, Australia—have therefore come up with a neat improvement: instead of grafting new skin to the burned area, they spray the new skin on.

The source of the spray-on skin is the same as that of a traditional graft—a piece of undamaged skin tissue from the patient in question. But once this tissue has been removed, the treatment is completely different. First, the excised skin is bathed in an enzyme solution that separates its cells from one another. Then, using a syringe or a pneumatic spray, the surgeon squirts the cells on to the wound. The whole process, including the separation of the cells, can be completed in 70-90 minutes (a traditional skin graft takes between ten minutes and an hour, depending on the size of the affected area), and the burns thereafter heal at the same rate as those which have received traditional grafts, recovering fully after 12-13 days. 

One advantage of the new method is the amount of coverage that can be achieved with a given amount of healthy skin. In a normal graft, the skin is stretched to three or four times its original size before being attached to the wound. That reduces the amount that needs to be taken, but stretching any further risks mesh-like scars appearing in the healed area.

The new method, however, can cover an area at least 20 times the size of the healthy skin it uses. The sprayed cells form islands across the burn and multiply rapidly to create a continuous surface. Indeed, Dr Wood says she has been able to use a piece of skin the size of a postage stamp to cover a burn across the whole of child’s chest.

There are other benefits, too. The researchers suggest spray-on skin results in less scarring than normal grafting, even when a graft has not been overstretched. And the need to remove only a small piece of skin means it is easier to match the colour of the grafted tissue to the place where it is going. In fact, Dr Wood says she sometimes sands down existing, discoloured burn scars and sprays them with skin cells to achieve a better tone.

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