A skin graft is the replacement of healthy skin onto an area where the skin has been damaged, lost or surgically removed. The healthy skin is harvested from a donor site (also called a source site) and transplanted to the recipient site.
Who Needs a Skin Graft?
Skin grafting is performed to provide a protective barrier and to promote healing of open wounds resulting from trauma or infection, burns, venous (varicose) ulcers, pressure ulcers (bedsores), or diabetic ulcers that do not heal with normal treatment. They are also often performed as part of post-mastectomy breast reconstruction and other surgery to remove cancerous cells.
Where Does the Skin for a Skin Graft Come From?
The most successful skin grafts are usually those wherein the patient’s own skin is harvested from another area of the body (called an autograft). Skin grafts can also often be successful when harvested from an identical twin of the patient.
When a separate donor is not an identical twin, there is a stronger chance of the body rejecting the new skin, seeing it as an invading foreign body and attacking it via the immune system. However, even if the donor skin is rejected, the graft may be successful in many cases by giving the patient’s body enough time and protection to grow back new skin on its own.
Alternate graft sources are meant only for temporary use until the patient’s own skin grows back. These alternatives include:
- Skin taken from a cadaver (called an Allograft)
- Skin taken from an animal (called a Xenograft)
- Synthetic tissue
With an autograft or graft taken from a twin, your surgeon will take care whenever possible to harvest the donor skin from a part of the body normally covered by clothes. Your surgeon will try to match skin color and texture as closely as possible between the donor and recipient sites. Common donor sites include the inner thigh and buttocks (which are the most common), as well as the upper arm, forearm, back, and abdomen.
Skin Graft Techniques
There are three main types of skin grafts:
A split-thickness graft is the most commonly used type of skin graft. It removes only the epidermis (the top layer of skin) and part of the dermis (the middle layer of skin). This allows the source site to heal more quickly. However, this type of graft is more fragile, and it may leave the donor site with abnormal (lighter) pigmentation.
A full-thickness graft removes the epidermis, the dermis, and the hypodermis (the bottom layer of the skin) in their entirety. Cosmetically, the outcome is usually better, which is why full-thickness grafts are usually recommended for the face. However, the use of full-thickness grafts is somewhat limited by the fact that they can only be placed on areas of the body that have significant blood vessels to ensure the graft’s survival.
A composite graft can entail the removal of skin, fat, muscle, and cartilage. These grafts are typically used in areas that require three-dimensional reconstruction, such as the nose.
Risks & Complications of Skin Grafts
Risks and potential complications of skin grafts include:
- rejection/loss/death of the graft
- unsatisfactory aesthetic results, such as scarring, skin texture irregularities or discoloration
- loss or reduction in skin sensation
- increased sensitivity; chronic pain (rarely)
- anesthesia risks
Skin grafts carry more risks for young infants, or those over the age of 60. Smokers and those with chronic illness are also at higher risk, as are patients taking certain medications such as high blood pressure drugs, muscle relaxants, and insulin.
How a Skin Graft Is Done
The wound is prepped for surgery. The wound is cleaned and measured, and then a pattern is traced for transfer over to the donor site.
Anesthesia is administered. Depending on the size, severity, and location of the wound, as well as the type of graft, the procedure may require local anesthesia, regional anesthesia, iv sedation, general anesthesia, or a combination thereof.
The donor skin is harvested and prepared. The skin is either removed with a scalpel, or with the help of a special harvesting machine called a dermatome. The graft may also be “meshed,” a process wherein multiple controlled incisions are placed in the graft. This technique allows fluid to leak out from the underlying tissue and the donor skin to spread out over a much larger area.
With a full-thickness or composite graft, the donor site is then closed with sutures. With a split-thickness graft, sutures are not needed at the donor site.
The graft is placed on the recipient site. Once in place, the graft is fastened to the surrounding tissues with sutures or staples.
A pressure bandage is applied over the graft recipient site. A special vacuum apparatus called a wound VAC may be placed over the area for the first 3 to 5 days to control drainage and increase the graft’s chances of survival.
Healing begins. At first, the graft uses oxygen and nutrients from the tissue at the recipient site to survive. New blood vessels begin to grow within the first 36 hours, followed by new skin cells which then begin to grow from the graft to cover the recipient area with new skin.
Post-Op Care: Both the donor and recipient sites should be kept moist and well-protected. Your physician will instruct you on the proper use of medications and bandaging.
Full Thickness Skin Graft Cover for Lower Limb Defects Following Excision of Cutaneous Lesions; Krishna Rao, Omar Tillo, Milind Dalal; Dermatology Online Journal, Volume 14, #2
Full-Thickness Skin Grafts: Maximizing Graft Take Using Negative Pressure Dressings to Prepare the Graft Bed; Alex G. Landau, Don A. Hudson, Kevin Adams, Stuart Geldenhuys, Conrad Pienaar; Annals of Plastic Surgery:Volume 60(6), June 2008, p 661-666
Skin Grafts, Consumer Information Sheet from the American Society of Plastic Surgeons
Skin Grafts; Mackay DR, Miraliakbari R, eds.; Operative Techniques in General Story; December 2006; 8(4); 197-206.