Реферат на тему Skin Grafts Essay Research Paper SKIN GRAFTS
Skin Grafts Essay, Research Paper
SKIN GRAFTS Burn Classifications Burns are classified according to the depth of damage to tissues. First-degree burns that in which only the outer layer of skin (the epidermis) is burned. The skin is red and there may be swelling or pain. In second-degree burns, the top layer of skin has been burned through and the second layer of skin (dermis) is also burned. Blisters develop, accompanied by pain and swelling. First- and second-degree burns, typically can be treated with first aid measures at home, but it depends on how large an area and what area of the body is affected. Generally, first- and second-degree burns will heal after a good cleaning and bandaging, and dont require skin grafting. Extensive third-degree burns, however, usually require treatment at burn care centers. All layers of skin are damaged and sometimes fat, nerve, tendon, muscle, and even bone are affected. Third-degree burns result in open wounds. These wounds must be cleansed and protected to minimize infection. Infection is the leading cause of death among burn patients. Initial treatment of third-degree burns depends on the depth and extent of the burn and the overall health of the patient. There are many kinds of wound dressings for superficial burns. But when burns are deep and cover a large portion of the body, skin grafts are usually necessary (6, pp. 1-4).Overview Skin grafts are layers of skin, which are taken from a sui donor area of a patient and transplanted to a recipient area of damaged skin. Skin grafts can either be split thickness, a very thin layer or part of the skin or full thickness layers which include all the layers of the skin. Thinner grafts survive transplantation more readily and are more successful. They are used for heavily contaminated surfaces, burn areas, and surfaces with poor blood supply. However they are least like normal skin with loss of suppleness, hair does not tend to grow on them and their final appearance can be a disappointment. Full thickness grafts are more pleasing to the eye, look more like skin, and can withstand a greater amount of trauma once thy are successfully implanted. Meshed grafts allow for a greater degree of covering because the original graft is rolled under a perforating machine and the perforations produced allow for expansion thus increasing the surface area of the graft. Skin grafting is used to replace skin cover. It is used in the treatment of burned areas of skin, varicose ulcers, and after the surgical excision of skin cancers, including malignant melanomas. Infection and lack of satisfactory blood supply prevent some grafts from surviving. A local skinflap is used when the blood supply is poor and it is thought that the area to be grafted will not allow a successful free skin graft. Two areas such as the legs are brought into close proximity and held together by a plaster cast. A flap of skin can be partially removed from the donor area on one leg and transferred over to the recipient area on the other leg. It still retains its blood supply from its connection through the flap with the donor area. There are many variations of skin flaps which use techniques to maintain a blood supply while a potential graph is establishing itself (5, pp. 1).The History of Skin Grafts Tissue transplants have figured prominently in mythology since the legend of the creation of Eve from one of Adams ribs. Historical accounts of surgical tissue grafting as part of the cure for patients dates back to the early Hindu surgeons who, about the beginnings of the 6th century BC, developed a technique for reconstructing noses from skin flaps taken from the patients arm. This method was introduced into Western medicine by Gaspare Tagliacozzi in the 16th century. The flap was left attached to the arm for two to three weeks until new blood vessels had grown into it from the nose remnant. The flap was then severed and the arm freed from the reconstructed nose. Karl Ferdinand von Grafe (born March 8, 1787) was a German surgeon who helped create modern plastic surgery. A superintendent of German military hospitals during the Napoleonic Wars, he also served as professor of surgery and director of the surgical clinic at the University of Berlin. He improved the English surgeon Joseph Carpues adaptation of the Indian method and revived the 16th century surgeon Taccacozzis Italian method of plastic surgery on the nose. The Indian method uses a skin graft from the forehead and the Italian from the upper arm. Grafe also made technical improvements in the administration of blood transfusions (4, pp. 2).Procedure and First AidA skin graft, literally speaking, is taking skin from one area of the body and attaching it another area where no skin exists. The body part involved is the skin (donor and recipient sites). Extensive wounds, burns, or certain surgeries may require skin grafts for healing to occur. There are many things that increase the surgical risk. Adults over sixty are at risk because statistics say that they will probably be in worse health than a younger person and the skin on someone over sixty may have problems such as dryness, less elasticity, and overall health of the skin. Newborns and infants are also at risk because they are more susceptible to infection and have a weak immune system. Obesity, smoking, and poor nutrition also increase the risks of a surgical skin graft because of poor skin elasticity, excessive layers of fat under the dermis and/or places where the skin is stretched too taunt. People with anemia run a high risk of problems because any procedure at all will cause extreme bleeding. Skin Grafting will have trouble on people with chronic illnesses because the body may trouble adhering to the graft. Drug users run a greater risk of dying when any kind of surgery is done, much less skin grafting. A general surgeon or plastic and reconstructive surgeon usually performs the operation. The operation is done in a hospital, outpatient facility, or the emergency room. Blood and urine tests must be ran before surgery and blood studies must be ran afterwards. Either a local or a general anesthesia may be used. The procedure for operating is as follows; skin is removed from the donor site and the donor site is covered with gauze. Debris is cleared from the recipient site. The skin from the donor site is placed on the recipient site and fastened at each end with sutures. Bandages are applied and new blood vessels begin growing from the recipient area to the transplanted skin with in thirty-six hours. As with all surgeries, there are possible complications which may occur. For starters, excessive bleeding may occur and the wound could become infected. There are also cases in which the serum collects under the recipient site that prevents the growth of new blood vessels. The skin graft may also be completely lost. The average hospital stay is two to twelve days, depending on the extent of the surgery. After being released from the hospital allow about six weeks for recovery. Most skin grafts are successful, but in some cases they dont take and must be done again. This often occurs if skin edges are injured from stitches. Skillful postoperative nursing care is critical to the success of the skin graft. For postoperative care apply a non-prescription antibiotic ointment to new bandages, if instructed by your doctor. Be sure to keep bandages dry while bathing. If a bandage does get wet, quickly change it. You may also use non-prescription drugs, such as acetaminophen, for minor pain. You may return to work and other daily activities as soon as possible to promote elasticity and healing. Avoid vigorous exercise for at least six weeks following surgery and resume driving after one week. Also, there is no special diet involved. Call your doctor if there is any pain, swelling, redness, drainage, bleeding, or odor in the surgical area. Also contact your doctor if there are signs of infection or if you experience headaches, muscle aches, dizziness, or a general ill feeling and a fever. Many drugs will produce side effects but contact your doctor anyway if any new symptoms occur. If you follow these instructions on how to take care of a surgical skin graft then you heal up rather well (7, pp. 735-746).Skin Grafting For now, the only permanent replacement for human skin is human skin. In what is known as an autograft, surgeons remove healthy skin from another part of the burned persons body and graft it to the burned area to cover the wound. Grafted skin is usually very thin and doesnt contain sweat and oil glands or hair follicles. It covers but doesnt function as well as healthy skin. Sometimes an autograft is not an immediate option. Some one may have burns over eighty percent of their body and not have very much donor skin to use as an autograft. Or the person may be too weak to withstand the additional wound created at the autograft donor site. Sometimes multiple autografts are necessary to cover affected areas. More than one donor site may be used, or one3 site may be used and then allowed to heal, and used again. Typically, multiple surgical procedures are required (1, pp. 173-176).Skin Growth and Skin SubstitutesReasoning When a patient is burned so badly that there are no donor sights large enough or sui enough for autograft other solutions must be found. In these cases surgeons can use skin substitutions and synthetic wound coverings to close the wound until autografting becomes possible. These artificial alternatives reduce the number of surgical procedures necessary and speed up recovery. These products save lives, says George L. Peltier M.D., chief of plastic surgery at Hennipen County Medical Center in Minneapolis, Minnesota. Dr. Peltier has been treating burn patients for over twenty years. We dont know all the advantages of substitute skins yet. We are still learning. Theyre very expensive, but result in fewer surgical procedures. Which means reduced pain for the patient and a shortened hospital stay, he says.
Skin Cultures In one method of obtaining substitute skin, human skin is grown in a lab for use in grafting. A postage stamp sized piece of normal skin from a burn patient is sent to a lab where it is grown in special tissue cultures. If all goes well, in three weeks enough skin can be cultured to be used in grafting. Although cultured skin is very expensive it has many advantages. Surgeons may also take skin from a cadaver (homograft or allograft) or even an animal (xenograft) and use it as a temporary covering for a burn. The problem with this is a body is designed to accept only its own skin and will eventually reject skin from outside donors. Homografts and xenografts theore must eventually be replaced by skin from the burn patient. To avoid such problems, researchers and manufacturers must develop synthetic skin. A new synthetic product called Dermagraft-TC made from living human cells is now being used in place of cadaver skin. Its very costly but it is pathogen-free and more widely available. The Food and Drug Administration has approved this and an artificial interactive burn dressing known as Integra Artificial Skin Dermal Regeneration Template for treating third-degree burns. Integra is a two layered dressing. The top layer serves as a temporary synthetic epidermis; the layer below serves as a foundation for the regrowth of dermal tissue. The underlying layer is made up of collagen fibers that act as a lattice through which the body can begin to align cells to recreate its own dermal tissue. Both Dermagraft and Integra will be discussed later in more detail (8, pp. 1-3). Dermagraft-TC Imagine a foreskin as long and as wide as six football fields. It sounds like a joke but it will all come true within a year. A company called Advanced Tissue Sciences in San Diego, California, plans to manufacture human skin grown in vats on an industrial scale using tissue from circumcised babies. From each tiny foreskin this company will generate 23,225 square meters of human skin, enough to cover six football fields. It will be used in transplants, for treating burn victims, and for diabetic ulcer patients. Skin is one type of tissue that continues to proliferate throughout your life, and that is very useful, said researchers at ATS. Advanced Tissue Sciences laboratories reveal a host of startling biological wonders: scientists growing heart valves made of human tissue and constructing ears out of cloned cartilage. Similar work is going on with human livers, bones, intestine walls, and ligaments. But skin production leads the field, thanks to scientists who have overcome the basic problem of how to grow tissue cells. In the past, attempts at skin cultivation were made. These attempts failed because they were tried on flat, two-dimensional surfaces. Only recently did researchers solve this problem. They built three-dimensional scaffolds for skin to adhere to. This is how Advanced Tissue Sciences is growing its foreskins. Cells are separated, dissolved, and the solution passed over lattices of biodegradable meshes. The skin then adheres to, or sticks to these meshes. Nutrients and chemicals are added to stimulate growth, producing a patch of skin measuring 10 by 15 centimeters that is frozen and stored for use by surgeons. This company hopes to create two major businesses from these skin patches. The first will treat foot ulcers for diabetics, of which there are 400,000 of in the U.S. These ulcers, if left untreated, can turn into large wounds leading to gangrene and amputations. High, encouraging success rates were reported in clinical trials. Not only does the dermal patch adhere to the wound, but also the patients own epidermis closes over to complete the healing. The second venture will use the skin patches to treat fire victims. Treatment with dermal patches should provide the answer, the company says, providing protection from infection. The patient also runs no risk of rejection. These pieces are removed once the patients own skin is ready for transplant. The technique has already had no success. Benjamin was a fifteen-year-old who set fire to himself while making a homemade bomb from a bottle of gasoline and a firecracker. He suffered massive third-degree burns and, because local hospitals had run out of cadaver skin, might have died if this Dermagraft-TC had not been available. Benjamin has now fully recovered (2, pp.3).Integra Integra is a bilayer membrane system for skin replacement. The dermal replacement layer is made up of a porous matrix of fibers of cross-linked bovine tendon collagen and a glycosaminoglycan that is manufactured with a controlled porosity and defined degradation rate. The temporary epidermal substitute layer is made up of synthetic polysiloxane polymer (silicone) and functions to control moisture loss from the wound. The collagen dermal replacement layer serves as a matrix for the infiltration of fibroblasts, macrophages, lymphocytes, and capillaries derived from the wound bed. As healing progresses an endogenous collagen matrix is deposited by fibroblasts; simultaneously, the dermal layer of Integra Artificial skin is degraded. Upon adequate vascularization of the dermal tissue layer and the availability of donor autograft tissue, the temporary silicone layer is removed and a thin, meshed layer of epidermal autograft is placed over the neodermis. Cells from the epidermal autograft grow and form a confluent stratum corneum, thereby closing the wound reconstituting a functional dermis and epidermis. Integra Artificial Skin is a skin replacement system for the treatment of deep partial-thickness or full-thickness thermal injury to the skin. It is applied following excision of the burn wound to viable tissue. It serves two very critical functions. It is available without delay and functionally closes the excised wounds immediately without the need to create donor site wounds. Following application, it functions as an artificial skin that provides immediate postexcisional wound homeostasis, facilitating patient recovery and relieving metabolic stress. It serves as a template to generate a neodermis, a dermal-like tissue that readily accepts very thin epidermal autografts. Formation of the neodermis generally takes 14-21 days. After the neodermis is formed, the silicone layer is easily removed and a very thin meshed and widely spread epidermal autograft can be applied over the neodermis. These thin, epidermal autografts result in less donor site morbidity than conventional split-thickness autografts. The cosmetic results are excellent, exceeding the results for a conventional meshed autograft. Since the epidermal autograft can be applied immediately after the neodermis has formed (usually 14-21 days after application), the application of the epidermal autograft can also be scheduled at a time when sufficient donor sites are available and the patients condition is sui for a grafting procedure. In a clinical trial Integra remained in place for up to seventy-three days prior to epidermal autografting. The neodermis tissue formed by Integra is distinct from granulation tissue, which is not a desirable bed for epidermal autografts. Granulation tissue, which may form at joints between Integra sheets or in areas affected by infection or other problems will typically have a deep red, granular appearance and bleeds easily. In contrast, the neodermis that is visible under the silicone layer, or that is exposed after the removal of the silicone layer, is typically yellow to orange in color with patches of light red. After final healing of the wound, the neodermis tissue histologically and functionally is similar to the normal dermis (3, pp. 1-4).In Closing Skin substitutes and advanced wound dressings are only temporary fixes. They create a good base onto which skin, once available, can be autografted. Typically, with the use of substitute skin, thinner autografts are used. That means the donor sight will heal more quickly. According to the American Burn Association, every year between 60,000 and 80,000 people are hospitalized each year in the United States for burn treatment. At least five thousand of these die. The good news is that better treatment of burns has reduced mortality rates and improved the quality of life for burn survivors. In the early 1950s, a child with third-degree burns to over fifty percent of his body only had a 50/50 chance of surviving. Thanks to new skin grafting techniques and the technological advances made to grow artificial protective skins such as Dermagraft-TC and Integra Artificial Dermal Regeneration Template that same child has a ninety-five percent or better chance of surviving. The only sure bet to survival is to prevent yourself or someone you love from suffering a serious burn injury. Bibliography 1. Annals of Plastic Surgery (1997), Vol. 38, Iss. 2, p. 173-176. 2. McKie, R. (1995, April 4), Foreskins for Skin Grafts. Toronto Star section A, p. 3. 3. Product . (1997), Integra LifeSciences p. 1-4. 4. Skin Graft. (1997) Thrive Online [internet site), p. 1-3. 5. Skin Grafts. (1997), Plastic Surgery, Medical Online [internet site), Immediate Assistants Pty. Ltd., p. 1. 6. Skin Substitutions. (1997), Mayo Health Oasis [internet site), Mayo Foundation for Medical Education and Research, p. 1-4. 7. Stern, R. (1990), Journal for Burn Care and Rehabilitation, Vol. II, No. 1, January, February, p. 735-748. 8. Strange, Caroline J. (1997), Second Skins. New Options for Burn Victims, Child Secure [internet site) p. 1-3.