A skin graft is a piece of healthy skin that replaces diseased tissue. It is a procedure most commonly used over a badly injured area, or places with skin ulceration, severe burns, and chronic infections. The healthy skin is usually taken from a different location on the afflicted person, but can come from a number of places.
There are five types of skin grafts. The most common type is an autograft, when the healthy skin is taken from a donor site on the injured person's own body. Donor areas are generally a large site where skin is plentiful and circulation will be strong to help with healing, such as the leg.
Other types of grafts are less common, but still valid. An allograft is a skin graft taken from another human donor. A xenograft is a non-permanent skin graft made up of non-human tissue, usually from pigs, that temporarily seals a wound while healing but will eventually be rejected by the body. An isogeneic skin graft is when the donor is genetically identical to the recipient, such as with identical twins. The last kind of skin graft is prosthetic, which is the use of non-tissue or synthetic material, like plastic, to seal the wound.
A skin graft can be classified as partial or full thickness. A partial skin graft is most common and involves shaving a layer of skin from the donor site. A full thickness graft is taken by digging several layers in the epidermis of the donor site to take a thick chunk of the skin. This thicker sample leaves a less visible scar in the recipient area, but a significant gap in the donor area that must be attended to.
The procedure usually begins with general anesthesia. The donor area is cleaned and a tool called a dermatome shaves away a layer of skin from the site. Sometimes surgeons choose to slice the skin into a basket weave pattern, a step that some believe helps in the healing process. The recipient area is also cleaned and the donor skin is placed over the wound. Sutures hold the new skin in place, while pressure is placed on the area with gauze, netting or casting to help the skin adhere.
Following the procedure, the donor area is usually quite sore. Both sites are monitored for infection and bleeding. The recipient site will be checked regularly to ensure that the new skin is being accepted. If the procedure is successful, full recovery takes about three or four weeks.