Walter Yeo, before and after a skin graft in 1917. Yeo is thought to be the first person to benefit from plastic surgery. (courtesy Wikimedia Commons)
A skin graft is a type of transplant where skin from a donor, or even the individual's own skin, is used to repair damage to the recipient's skin. It is often used in cases of severe trauma and burns.
In order to perform a skin graft, the existing damaged skin must usually be completely removed. For the transplant, either the thin top layer of skin can be used (which is less likely to be rejected, but results in more scarring) or all layers of skin can be used, which results in almost no scarring (except at the edges), but increases the risk of complications.
Episodes discussing skin grafts are Distractions, where the patient was in need of them, and Words and Deeds, where the patient had recently recovered from extensive grafts.
A modern graft, here used to repair damage from trauma, courtesy Paul Farrant, via Wikimedia Commons