| 释义 |
skin grafting
skin graftn. A surgical graft of healthy skin from one part of the body to another or from one individual to another in order to replace damaged or lost skin.
skin grafting n.skin′ graft`ing
n. the surgical process of transplanting skin to a wound or burn in order to form new skin. [1875–80] EncyclopediaSeeskin graftSkin Grafting
Skin Grafting DefinitionSkin grafting is a surgical procedure by which skin or skin substitute is placed over a burn or non-healing wound to permanently replace damaged or missing skin or provide a temporary wound covering.PurposeWounds such as third-degree burns must be covered as quickly as possible to prevent infection or loss of fluid. Wounds that are left to heal on their own can contract, often resulting in serious scarring; if the wound is large enough, the scar can actually prevent movement of limbs. Non-healing wounds, such as diabetic ulcers, venous ulcers, or pressure sores, can be treated with skin grafts to prevent infection and further progression of the wounded area.PrecautionsSkin grafting is generally not used for first- or second-degree burns, which generally heal with little or no scarring. Also, 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.DescriptionThe skin is the largest organ of the human body. It consists of two main layers: the epidermis is the outer layer, sitting on and nourished by the thicker dermis. These two layers are approximately 0.04-0.08 in (1-2 mm) thick. The epidermis consists of an outer layer of dead cells, which provides a tough, protective coating, and several layers of rapidly dividing cells called keratinocytes. The dermis contains the blood vessels, nerves, sweat glands, hair follicles, and oil glands. The dermis consists mainly of connective tissue, primarily the protein collagen, which gives the skin its flexibility and provides structural support. Fibroblasts, which make collagen, are the main cell type in the dermis.Skin protects the body from fluid loss, aids in temperature regulation, and helps prevent disease-causing bacteria or viruses from entering the body. Skin that is damaged extensively by burns or non-healing wounds can compromise the health and well-being of the patient. More than 50,000 people are hospitalized for burn treatment each year in the United States, and 5,500 die. Approximately 4 million people suffer from non-healing wounds, including 1.5 million with venous ulcers and 800,000 with diabetic ulcers, which result in 55,000 amputations per year in the United States.Skin for grafting can be obtained from another area of the patient's body, called an autograft, if there is enough undamaged skin available, and if the patient is healthy enough to undergo the additional surgery required. Alternatively, skin can be obtained from another person (donor skin from cadavers is frozen, stored, and available for use), called an allograft, or from an animal (usually a pig), called a xenograft. Allografts and xenografts provide only temporary covering-they are rejected by the patient's immune system within seven to 10 days and must be replaced with an autograft.A split-thickness skin graft takes mainly the epidermis and a little of the dermis, and usually heals within several days. The wound must not be too deep if a split-thickness graft is going to be successful, since the blood vessels that will nourish the grafted tissue must come from the dermis of the wound itself.A full-thickness graft involves both layers of the skin. Full-thickness autografts provide better contour, more natural color, and less contraction at the grafted site. 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 sometime used, consisting of combinations of skin and fat, skin and cartilage, or dermis and fat. Composite grafts are used where three-dimensional reconstruction is necessary. For example, a wedge of ear containing skin and cartilage can be used to repair the nose.Several artificial skin products are available for burns or non-healing wounds. Unlike allographs and xenographs, these products 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. This artificial dermis, the fibers of which are arranged in a lattice, acts as a template for the formation of new tissue. Fibroblasts, blood vessels, nerve fibers, and lymph vessels from surrounding healthy tissue cross into the collagen lattice, which eventually degrades 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. The cost for the synthetic products in about $1,000 for a 40-in (100-cm) square piece of artificial skin, in addition to the costs of the surgery. This procedure is covered by insurance.AftercareOnce a skin graft has been put in place, even after it has healed, it must be maintained carefully. Patients  Skin grafting is a surgical procedure by which skin or a skin substitute is placed over a burn or non-healing wound to replace the damaged skin or provide a temporary wound covering. Skin for grafting can be obtained from another area of the patient's body, such as the face and neck, as shown in the illustration above. (Illustration by Electronic Illustrators Group.)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 in 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 a bland oil (e.g., mineral oil) to prevent drying and cracking.RisksThe risks of skin grafting include those inherent in any surgical procedure that involves anesthesia. These include reactions to the medications, problems breathing, bleeding, and infection. In addition, the risks of an allograft procedure include transmission of infectious disease.Normal resultsA 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.Key termsAllograft — Tissue that is taken from one person's body and grafted to another person.Autograft — Tissue that is taken from one part of a person's body and transplanted to a different part of the same person.Collagen — A protein that provides structural support; the main component of connective tissue.Dermis — The underlayer of skin, containing blood vessels, nerves, hair follicles, and oil and sweat glands.Epidermis — The outer layer of skin, consisting of a layer of dead cells that perform a protective function and a second layer of dividing cells.Fibroblasts — A type of cell found in connective tissue; produces collagen.Keratinocytes — Cells found in the epidermis. The keratinocytes at the outer surface of the epidermis are dead and form a tough protective layer. The cells underneath divide to replenish the supply.Xenograft — Tissue that is transplanted from one species to another (e.g., pigs to humans).Abnormal resultsFailure of a graft can result from poor blood flow, swelling, or infection.ResourcesOrganizationsAmerican Burn Association. 625 N. Michigan Ave., Suite 1530, Chicago, IL 60611. (800) 548-2876. http://www.ameriburn.org.American Diabetes Association. 1701 North Beauregard Street, Alexandria, VA 22311. (800) 342-2383. http://www.diabetes.org.grafting [graft´ing] transplantation. The term grafting is preferred in the case of skin grafting and of synthetic grafts such as arteriovenous grafts.skin grafting implantation of patches of healthy skin on a denuded area to provide epithelial covering; the skin may come from another area with healthy skin from the patient's own body or from the body of a skin donor. The most important function of skin grafting is to promote healing of large surfaces that have been burned or wounded, or that have become ulcerous or cancerous. If burns or other injuries are extensive, grafting can prevent extensive scarring with unsightly tissue that cannot perform all the necessary functions of normal skin. Skin contractures can thus be avoided.
The skin to be grafted is cut usually from the chest, thigh, buttock, abdomen, lower part of the neck, or behind the ear. It may be removed in very thin strips or as a thin layer of superficial skin, and it must be placed in its new location without delay. If delay is unavoidable, it is placed in a saline solution or refrigerated. In this kind of free graft, the skin is cut entirely away from the body before transplantation and then is sewed into place; a pressure dressing is applied or a tissue glue is used. Afterwards the skin must depend for its nourishment on the surrounding tissue in the new location.
If a large thick area of skin containing much underlying tissue is to be moved, the traditional method has been to do this by means of a flap" >pedicle flap. For example, an injured hand that needs skin grafting would be strapped against the abdominal wall to receive a pedicle graft of skin from the abdomen. However, the introduction of microsurgery has eliminated much of the need for this kind of graft.
A skin graft can sometimes be made by the simple procedure of cutting a piece of healthy skin from one part of the body, such as the back or the thigh, and stitching it to the injured area. Small arteries from the tissues surrounding the injured area then grow into the graft, nourish it with blood and promote normal growth. If the area to be covered is large, a number of separate patches may be stitched to it, forming islands of skin that will enlarge with healing until the entire area is covered. This is called “postage stamp” or pinch grafting.
With the advent of microsurgery, much of the inconvenience and lengthy waiting necessary for successful grafting of skin flaps have been eliminated. It is now possible for a surgeon to perform what are called free-tissue transfers. The skin flap is removed from the donor site and transferred directly to the distant recipient site where circulation to the free flap is reestablished by microvascular anastomoses.
There are many different types of grafts" >skin grafts, including dermal or dermic, epidermic, full-thickness, split-thickness, thick-split, inlay, mesh, pinch, sieve, and Ollier-Thiersch grafts. See also flap. |