Publications & Presentaions
SPLIT SKIN GRAFTING
What is Split Skin Grafting?
Split skin grafting is the harvesting of the top few layers of the skin in order to place it in a different part of the body as a patch. This results in the healing of an area without skin. The area from which the skin was taken, called the donor site, heals by itself, rather like having a graze. Split skin grafts are used to cover all sorts of defects, whether this is following an accident, or a burn, or the elective removal of a skin lesion, tattoo, or unsatisfactory scar.
What happens in the Operation?
The recipient site is first prepared surgically to ensure a healthy wound bed. The split skin graft is then harvested using a special surgical knife, or a machine called a dermatome. This allows a very specific depth of skin to be removed in a similar way to a potato peeler. The skin graft can then be used either as a sheet graft, which gives a good cosmetic effect, or as a meshed graft. This meshing process involves the cutting of small holes in the skin, producing an effect rather like a string vest, which allows the skin to be stretched further, and also allows any bleeding underneath the skin to come out. Although this results in easier healing, the cosmetic result is not as good, because the pattern is visible in the scar later. Even if a sheet of skin is used, it is still necessary to make small holes in it in order to help with drainage, but these are much less obvious in the future than with the mesh patterns.
The skin graft is attached to the original wound either with staples or stitches, and occasionally skin glue. A dressing is then put on in order to hold the skin graft securely while it heals. In order to heal, the skin graft needs to collect blood supply from the underlying surface. New blood vessels grow up from the wound bed into the skin graft and it gradually incorporates. These blood vessels are very small, and any movement or obstruction will prevent this process taking place. Bleeding underneath the skin graft will provide a mechanical barrier against these little blood vessels growing through, and also any movement or shearing between the skin graft and its wound base can also damage these blood vessels.
Why must I not smoke after skin grafting?
When the skin graft is removed from the body, it does not have any blood supply, and therefore it is only a matter of time before the skin cells will die. A thin split skin graft is able to gather enough nutrition and oxygen supply from the wound bed to keep alive for the first few days until the new blood vessels grow. However, anything that stops the blood vessels growing in quickly reduces the chances of good take of the graft as the skin cells will gradually become less healthy, and will eventually die if the blood supply doesn’t get through.
Cigarette smoke contains nicotine, which causes constriction or squeezing of the small blood vessels. This results in very bad blood flow in the small vessels and also the prevention of new growth in the blood vessels for at least an hour after each cigarette. If you smoke heavily therefore, the risk of poor healing is very great with a split skin graft. After grafting, it is best not to smoke at all, however, it is better to smoke a cigarette quickly and keep the cigarettes close together, and then have a good break between cigarettes in order to allow adequate blood vessel growth.
Immediately after the Operation
After approximately five days, the graft will be inspected, and hopefully by then, it will have grown adequate blood supply, and be stabilised. It may be necessary to have the dressing for another week if the skin is a little fragile, however you should expect the graft to be fully stable at about two weeks. Any areas that are not healed by this time will normally heal by themselves, but it may be necessary occasionally to repeat the skin graft.
The donor site (where the skin came from) is like a deep graze, and will heal by itself. However, any movement between the wound and the dressing does cause pain, therefore we use an adhesive dressing that sticks to the wound and the skin around it to prevent any movement. A secondary dressing is placed over the top of this to collect any oozing blood etc, and this can be removed after 48 hours. 48 hours after removing the outer dressing, the donor site with the adhesive fabric, can be washed as if it were normal skin, with simple warm water and no soap. The area is then patted dry carefully and the dressing remains in position. As long as the dressing is washed daily, then the area remains supple, however if it is left then often there is a crusty scabbiness over the donor site which can be uncomfortable.
As the fabric dressing starts to lift off, any loose areas can be trimmed using a clean pair of scissors with care to avoid damaging the skin underneath. Gradually over a period of two to four weeks, the dressing will separate, and usually good healing has happened underneath. Occasionally there can be problems with healing and infection in donor sites, and these may require more frequent changes, and the removal of the original operative dressing and changing for conventional dressings. The healing of your donor site will also be dependant on blood supply , and therefore this is also affected by smoking .Your donor site shouldn’t leave any obvious scarring, unless it takes a very long time to heal. However there will always be a patch, which will be detectable, often with a different pigment, and a slightly different texture from your normal skin.
Graft Care after the dressings are removed.
The skin grafted area and the donor site can both be massaged with moisturising cream such as E45 or Diprobase, or simple aqueous cream bought from the chemist.
Over time, the skin will toughen up, and the donor site and the skin grafted area will become less red. The more massaging and moisturising you do, the quicker the wounds will settle down, and usually this process takes between 6-24 months, depending on your age and your healing potential.
Sun Protection
It is very important to protect the areas from direct sunlight, and a high factor sunblock should be applied. This both prevents any blistering and burning of the skin, which is more sensitive than usual, but also exposure to sun can result in pigment change within the maturing skin, which can result in a brown staining that is permanent.
The colouration of your skin graft and donor site should reflect your normal skin colour, however particularly in intermediate skin colourations, there can often be darker or lighter pigment in both the skin graft and the donor site. Skin pigment colour change can often take two years to settle to its final colour, during which time it should be protected from the sun.