A skin graft is where healthy skin is removed from an unaffected area of the body and used to cover lost or damaged skin.
There are 2 main types of skin graft.
Partial or split thickness skin graft
This is where a thin layer of skin (as thin as tissue paper) is shaved from an area that usually heals well, such as the thigh, buttocks or calf.
The donor area usually take 2 to 3 weeks to heal and is pink for a few months before fading to leave a faint (hardly noticeable) scar.
Full thickness skin graft
This is where the full thickness of skin (the top layer and layers underneath) are removed and the area is directly closed.
Sites often used include the neck, behind the ear, the upper arm and groin.
Because this type of skin graft is thicker, picking up a new blood supply can be more difficult, so any dressing will be left in place for 5 to 7 days before being removed by the surgical team.
The skin graft will usually be held in place using stitches, staples, clips or special glue.
The area will be covered with a sterile dressing until it has connected with the surrounding blood supply, which usually takes around 5 to 7 days.
A dressing will also be placed over the area where the skin has been taken from (the donor site) to help protect it from infection.
The donor area of partial thickness skin grafts usually takes about 2 weeks to heal.
For full thickness skin grafts, the donor area only takes about 5 to 10 days to heal, because it's normally quite small and closed with stitches.
At first, the grafted area will appear reddish-purple, but it should fade over time. It can take a year or two for the appearance of the skin to settle down completely.
The final colour may be slightly different from the surrounding skin, and the area may be slightly indented.
Tissue expansion is a procedure that encourages the body to "grow" extra skin by stretching surrounding tissue. This extra skin can then be used to help reconstruct the nearby area.
Examples of when tissue expansion may be used include breast reconstruction and repairing large wounds.
Under general anaesthetic, a balloon-like device called an expander is inserted under the skin near the area to be repaired.
This is gradually filled with salt water, causing the skin to stretch and grow.
The time it takes for the tissue to be expanded can vary, depending on the size of the area to be repaired.
If a large area of skin is affected, it can take as long as 3 or 4 months for the skin to grow enough. During this time, the expander will create a bulge in the skin.
Once the skin has expanded sufficiently, a second operation is needed to remove the expander and reposition the new tissue.
This technique ensures that the repaired area of skin has a similar colour and texture to the surrounding area.
There's also a lower chance of the repair failing because the blood supply to the skin remains connected.
Flap surgery involves the transfer of a living piece of tissue from one part of the body to another, along with the blood vessels that keep it alive.
It may be used for a variety of reasons, including breast reconstruction, open fractures, large wounds, and, in rare cases, for improving a cleft lip and palate.
In most cases, the skin remains partially attached to the body, creating a "flap". The flap is then repositioned and stitched over the damaged area.
For more complex reconstruction, a technique called a free flap is used.
This is where a piece of skin, and the blood vessels supplying it, are entirely disconnected from the original blood supply and then reconnected at a new site.
A technique called microsurgery (surgery using a microscope) is used to connect the tiny blood vessels at the new site.
A free flap is often used when large areas of specific tissue types are needed for reconstruction.
Depending on the location and size of the flap, the operation can be carried out under general or local anaesthetic.
As flap surgery allows the blood supply to the repaired area to be maintained, there's a lower risk of the repair failing compared with a skin graft.