SKIN GRAFTING 2

FULL-THICKNESS GRAFTS. Full-thickness skin grafts may be necessary for more severe burn injuries. These grafts involve both layers of the skin. Full-thickness autografts are more complicated than partial-thickness grafts, but provide better contour, more natural color, and less contraction at the grafted site. A flap of skin with underlying muscle and blood supply is transplanted to the area to be grafted. This procedure is used when tissue loss is extensive, such as after open fractures of the lower leg, with significant skin loss and underlying infection. The back and the abdomen are common donor sites for fullthickness grafts. The main disadvantage of full-thickness skin grafts is that the wound at the donor site is larger and requires more careful management.

Often, a split-thickness graft must be used to cover the donor site. A composite skin graft is sometimes used, which consists of combinations of skin and fat, skin and cartilage, or dermis and fat. Composite grafts are used in patients whose injuries require three-dimensional reconstruction. For example, a wedge of ear containing skin and cartilage can be used to repair the nose. A full-thickness graft is removed from the donor site with a scalpel rather than a dermatome. After the surgeon has cut around the edges of the pattern used to determine the size of the graft, he or she lifts the skin with a special hook and trims off any fatty tissue. The graft is then placed on the wound and secured in place with absorbable sutures.

Aftercare
Once a skin graft has been put in place, it must be maintained carefully even after it has healed. Patients who have grafts on their legs should remain in bed for seven to 10 days with their legs elevated. For several months, the patient should support the graft with an Ace bandage or Jobst stocking. Grafts on other areas of the body should be similarly supported after healing to decrease the amount of contracture.

Grafted skin does not contain sweat or oil glands, and should be lubricated daily for two to three months with mineral oil or another bland oil to prevent drying and cracking.

Aftercare of patients with severe burns typically includes psychological or psychiatric counseling as well as wound care and physical rehabilitation, particularly if the patient’s face has been disfigured. The severe pain and lengthy period of recovery involved in burn treatment are often accompanied by anxiety and depression. If the patient’s burns occurred in combat, a transportation disaster, terrorist attack, or other fire involving large numbers of people, he or she is at high risk of developing post-traumatic stress disorder (PTSD). Doctors treating the survivors of a nightclub fire in Rhode Island in February 2003 gave them anti-anxiety medications within a few days of the tragedy in order to reduce the risk of PTSD.

Risks
The risks of skin grafting include those inherent in any surgical procedure that involves anesthesia. These include reactions to the medications, breathing problems, bleeding, and infection. In addition, the risks of an allograft procedure include transmission of an infectious disease from the donor.

The tissue for grafting and the recipient site must be as sterile as possible to prevent later infection that could result in failure of the graft. Failure of a graft can result from inadequate preparation of the wound, poor blood flow to the injured area, swelling, or infection. The most common reason for graft failure is the formation of a hematoma, or collection of blood in the injured tissues.

Normal results
A skin graft should provide significant improvement in the quality of the wound site, and may prevent the serious complications associated with burns or non-healing wounds. Normally, new blood vessels begin growing from the donor area into the transplanted skin within 36 hours. Occasionally, skin grafts are unsuccessful or don’t heal well. In these cases, repeat grafting is necessary. Even though the skin graft must be protected from trauma or significant stretching for two to three weeks following split-thickness skin grafting, recovery from surgery is usually rapid. A dressing may be necessary for one to two weeks, depending on the location of the graft. Any exercise or activity that stretches the graft or puts it at risk for trauma should be avoided for three to four weeks. A one to two-week hospital stay is most often required in cases of full-thickness grafts, as the recovery period is longer.

Morbidity and mortality rates
According to the American Burn Association, there are more than 1 million burn injuries in the United States each year that require medical attention. Approximately one-half of these require hospitalization, and roughly 25,000 of those burn patients are admitted to a specialized burn unit. About 4,500 people die from burns each year in the United States.,

In the United States, someone dies in a fire nearly every two hours, on average, and another person is injured every 23 minutes. Approximately half the deaths occur in homes without smoke alarms. In addition to deaths resulting directly from burns, as many as 10,000 Americans die every year of burn-related infections, pneumonia being the most common infectious complication among hospitalized burn patients.

The average size of a burn injury in a patient admitted to a burn center is approximately 14% of the total body surface area. Smaller burns covering 10% of the total body area or less account for 54% of burn center admissions, while larger burns covering 60% or more account for 4% of admissions. About 6% of patients admitted to burn centers do not survive, mostly as a result of having suffered severe inhalation injuries in a fire. Treatment for severe burns has improved dramatically in the past 20 years. Today, patients can survive with burns covering up to about 90% of the body, although they often face permanent physical impairment.

Alternatives
There has been great progress in the development of artificial skin replacement products in recent years. Although nothing works as well as the patient’s own skin, artificial skin products are important due to the limitation of available skin for allografting in severely burned patients. Unlike allographs and xenographs, artificial skin replacements are not rejected by the patient’s body and actually encourage the generation of new tissue. Artificial skin usually consists of a synthetic epidermis and a collagen- based dermis.

The artificial dermis consists of fibers arranged in a lattice that act as a template for the formation of new tissue. Fibroblasts, blood vessels, nerve fibers, and lymph vessels from surrounding healthy tissue grow into the collagen lattice, which eventually dissolves as these cells and structures build a new dermis. The synthetic epidermis, which acts as a temporary barrier during this process, is eventually replaced with a split-thickness autograft or with an epidermis cultured in the laboratory from the patient’s own epithelial cells.

Several artificial skin products are available for burns or non-healing wounds, including Integra®, Dermal Regeneration Template® (from Integra Life Sciences Technology), Apligraft® (Novartis), Transcyte® (Advance Tissue Science), and Dermagraft®. Researchers have also obtained promising results growing or cultivating the patient’s own skin cells in the laboratory. These cultured skin substitutes reduce the need for autografts and can reduce the complications of burn injuries. Laboratory cultivation of skin cells may improve the prognosis for severely burned patients with third-degree burns over 50% of their body. The recovery of these patients has been hindered by the limited availability of uninjured skin from their own bodies for grafting. Skin substitutes may also reduce treatment costs and the length of hospital stays. In addition, other research has demonstrated the possibility of using stem cells collected from bone marrow or blood for use in growing skin grafts.

Patients with less severe burns are usually treated in a doctor’s office or a hospital emergency room. Patients with any of the following conditions, however, are usually transferred to hospitals with specialized burn units: third-degree burns; partial-thickness burns over 10% of their total body area; electrical or chemical burns; smoke inhalation injuries; or preexisting medical disorders that could complicate management, prolong recovery, or affect mortality.

In addition, burned children in hospitals without qualified personnel should be admitted to a hospital with a burn unit. A surgical team that specializes in burn treatment and skin grafts will perform the necessary procedures. The team may include neurosurgeons, ophthalmologists, oral surgeons, thoracic surgeons, psychiatrists, and trauma specialists as well as plastic surgeons and dermatologists.