Even the hair on Wiens' head, from the mid-scalp area, is part of the donor skin (the hair on the back of Wiens' head is his own).

CNN: Face transplant patient ready to go home

While burn damage is normally patched with pieces of excess skin from a person's own body, this does not work if the whole face needs to be covered -- the skin of the entire back is less than half of what would be needed to cover the full face and scalp, Siemionow said.

CNN: Face transplant patient regains self-confidence