Dear Straight Dope:
My husband and I were having a discussion and we don't have a clue. When a person has to have a skin graft, they try to use available skin from that person. What if they don't have enough skin to use? Do they wait for it to regrow? Can they get from other people such as family members? What about from another race?
Kathy C in Marceline MO
SDStaff Jillgat replies:
Can I get back to you on this? Out my front window I’m watching Doug the neighborhood goofus standing on the front bumper of his truck with his face about a foot from the engine, priming the carburetor with raw gasoline. I should have an answer for you soon.
The purpose of a skin graft is to cover an area of extensive skin loss after a person has been burned, wounded, had certain surgeries or, say, contracted necrotizing fasciitis (flesh eating bacteria). Ideally a permanent graft of the patient’s own skin is immediately placed over the burned area. This cuts down on infection and the patients do a lot better. Permanent grafts have to come from the patient — family or others can’t donate. So you can’t just make yourself multi-racial.
If too much skin is gone to permit grafting from elsewhere on the patient’s body, temporary grafts are placed first, then replaced with permanent grafts of the patient’s skin later. Temporary grafts typically come from cadaver skin — Joe, the charge nurse at the burn center in the hospital here, says it doesn’t matter what blood or race type the cadaver was–“it’s like a patchwork.” Cadaver skin is expensive and scarce, so sometimes they use pig skin for temporary grafts. I know a guy whose body probably wouldn’t reject that.
There are some new kinds of artificial skin on the market for use as temporary grafts. From an article in Scientific American, September 1997, “Growing a New Field”:
Integra consists of a porous matrix made from collagen (fibrous connective tissue from a cow) and a derivative of shark cartilage. The size of the pores induces new connective tissue and blood vessels from tissue underneath the dermis (inner skin layer) to grow into the biodegradable matrix. The manufactured dermis comes with a synthetic silicone covering, a substitute for the epidermis (top skin layer). The synthetic must be replaced with a graft of the patient’s own epidermis once the inner dermal cells have regenerated and the matrix has largely eroded.
So the patient gets a thinner permanent graft that’s less likely to scar badly.
Another new technique involves growing skin tissue from cells taken from circumcised infant foreskins. (This answers a question sent in by another sagacious member of the Teeming Millions: “What do they do with those after they cut them off?”) The tissue generated then serves as a temporary covering for burn patients or sometimes as a permanent graft for treatment of skin ulcers.
Permanent grafts: you don’t want to see the pictures of how they do this. Think vegetable peeler or cheese parer. They sheer off the top layer of skin from another part of the body, taking only the thickness that can heal naturally at the donor site, about .010 to .014 inch thick. It’s sutured into place over the cleaned wound. New blood vessels begin growing from the recipient area into the transplanted skin within 36 hours. Usually, but not always, the skin “takes.” Recovery, depending on the extent of the injuries takes about six weeks.
According to Joe at the burn center, guys who prime their carburetors with gasoline are “job security” for him. Next time I call my neighbor Doug “buttface,” I might not be far off.
SDStaff Jillgat, Straight Dope Science Advisory Board
Send questions to Cecil via firstname.lastname@example.org.
STAFF REPORTS ARE WRITTEN BY THE STRAIGHT DOPE SCIENCE ADVISORY BOARD, CECIL'S ONLINE AUXILIARY. THOUGH THE SDSAB DOES ITS BEST, THESE COLUMNS ARE EDITED BY ED ZOTTI, NOT CECIL, SO ACCURACYWISE YOU'D BETTER KEEP YOUR FINGERS CROSSED.