Dermatology Made Easy is based on the most popular topics from DermNet NZ's vast array of material. The book combines the essential focus of the ‘Made Easy’ book series with the authority and knowledge base of DermNet NZ's unparalleled resources.
Author: Dr Sonya Havill MBChB FRACP, Department of Dermatology, Waikato Hospital, Private Bag 3200, Hamilton, New Zealand, 2002.
A skin graft consists of skin taken from another part of the body and applied to the site where skin is missing. This may follow surgical removal of a skin cancer or an injury such as a burn or other trauma. A skin graft is a free piece of tissue without its own blood supply (as compared with a skin flap) and therefore its survival relies completely on a nutrients from the wound bed on which it is placed.
A skin graft is required when the area of skin loss is too big to be closed using local skin and stitches alone. The skin graft covers the wound and attaches itself to the cells beneath and begins to grow in its new location. If a skin graft wasn't performed, the area would be an open wound and take much longer to heal.
Your dermatologist will explain to you why a skin graft is required, and the procedure involved. You may have to sign a consent form to indicate that you understand and agree to the surgical procedure. Tell your doctor if you are taking any medication (particularly aspirin, clopidogrel, dabigatran and warfarin, which could make you bleed more), or if you have any allergies, medical conditions, or a pacemaker or implanted defibrillator. Remember, to tell your doctor about any over-the-counter supplements and herbal remedies as a number of these can also lead to abnormal bleeding.
After the excision (excision biopsy), your dermatologist will measure the area of the wound to know what size to make the skin graft. A piece of skin will be shaved or cut from another part of your body (e.g. leg or arm) that is large enough to cover the wound. When possible, skin of similar thickness and colour will be selected.
The piece of skin (the graft) will be applied to the wound and is usually secured in place with stitches. A special dressing will be applied directly over the skin graft and often sutured in place. A outer pressure dressing will then be applied to protect the wound.
Usually this dressing is left in place for approximately seven days until you see the dermatologist or nurse again. Make sure you have received instructions on how to care for the wound and when to get the stitches out. It is important to limit movement of the area for 2-3 days to allow time for the graft to adhere and develop a blood supply from the wound bed.
It is impossible to cut the skin without scarring of some degree. The final cosmetic result of a skin graft depends on many factors including the type of skin graft, the location, the size and depth of the wound, and patient factors. Because skin grafts are effectively a patch without their own blood supply and sometimes of less thickness than the wound they are applied to, the final appearance may not be as close to normal as it would be if the wound was able to be closed in a straight line or with a skin flap. The have a tendency to look paler and flatter than the surrounding skin with time.
You will have two scars, the scar where the skin graft has been applied and the scar from where the skin graft was taken (donor site). The donor site for a full thickness skin graft will usually be closed in a straight line with stitches. The donor site for a split thickness graft however will consist of a superficial graze and will heal itself more slowly (initially under a special dressing). This grazed area can often be tender post-operatively and require some oral pain relief such as paracetamol.
Some people have an abnormal response to skin healing resulting in larger scars than usual (keloid or hypertrophic scarring).
Split skin grafts
This type of skin graft is taken by shaving the surface layers (epidermis and a variable thickness of dermis) of the skin with a large knife called a dermatome. The shaved piece of skin is then applied to the wound. This type of skin graft is often taken from the leg. A split skin graft is often used after excision of a lesion on the lower leg.
Full thickness skin grafts
This type of skin graft is taken by removing all the layers of the skin with a scalpel (a Wolfe graft). It is done in a similar way to skin excision. The piece of skin is cut into the correct shape, then applied to the wound. This type of skin graft is often taken from the arm, neck or behind the ear. It is often used after excisions on the hand or face.
You will have two wounds, the site of the original lesion and the site where the skin graft was taken from (donor site).
Your wounds may become tender an hour or two after the excision when the effect of the local anaesthetic wears off.
Skin grafts are very fragile and great care must be taken when looking after them. Leave the dressing in place as advised by your dermatologist. Avoid strenuous exertion and stretching of the area until the stitches are removed and for some time afterwards.
If there is any bleeding, press on the wound firmly with a folded towel for 20 minutes (without removing the original dressing). If it is still bleeding after this time, seek medical attention. Do not rub the area as this may disturb the graft.
Keep the wounds dry until your dermatologist advises that you can wash them. If the wounds become red or very painful, consult your dermatologist: they could be infected.
Sometimes the skin graft does not survive the transfer to the new site. This usually happens within the first two weeks after the procedure. It can happen for a variety of reasons including the accumulation of blood or fluid underneath the graft, and/or wound infection. If this happens, your dermatologist will inform you what further treatment is required - a repeat skin graft procedure may be required or the wound may be dressed regularly and left to slowly heal on its own. It is quite normal for the graft to appear dark and crusted on the surface when the dressings are removed early on. This does not necessarily mean it has failed.
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