Skin grafting
Encyclopedia
Skin grafting is a type of graft surgery involving the transplantation of skin
. The transplanted tissue
is called a skin graft.
Skin grafting is often used to treat:
Skin grafts are often employed after serious injuries when some of the body's skin is damaged. Surgical removal (excision or debridement) of the damaged skin is followed by skin grafting. The grafting serves two purposes: reduce the course of treatment needed (and time in the hospital), and improve the function and appearance of the area of the body which receives the skin graft.
There are two types of skin grafts, the more common type is where a thin layer is removed from a healthy part of the body (the donor section) like peeling a potato, or a full thickness skin graft, which involves pitching and cutting skin away from the donor section. A full thickness skin graft is more risky, in terms of the body accepting the skin, yet it leaves only a scar line on the donor section, similar to a Cesarean section scar. For full thickness skin grafts, the donor section will often heal much more quickly than the injury and is less painful than a partial thickness skin graft.
Split-thickness
A split-thickness skin graft (STSG) is a skin graft including the epidermis and part of the dermis
. Its thickness depends on the donor site and the needs of the patient. It can be processed through a skin mesher which makes apentures onto the graft, allowing it to expand up to nine times its size. Split-thickness grafts are frequently used as they can cover large areas and the rate of autorejection is low. You can take from the same site again after 6 weeks. The donor site heals by re-epitheliasation from the dermis and surrounding skin and requires dressings.
Full-thickness
A full-thickness skin graft consists of the epidermis and the entire thickness of the dermis. The donor site is either sutured closed directly or covered by a split-thickness skin graft.
Composite graft
A composite graft is a small graft containing skin and underlying cartilage or other tissue. Donor sites include, for example, ear skin and cartilage to reconstruct nasal alar rim defects.
For more extensive tissue loss, a full-thickness skin graft, which includes the entire thickness of the skin, may be necessary. This is often performed for defects of the face and hand where contraction of the graft should be minimized. The general rule is that the thicker the graft, the less the contraction and deformity.
Cell cultured epithelial autograft (CEA) procedures take skin cells from the patient to grow new skin cells in sheets in a laboratory. The new sheets are used as grafts, and because the original skin cells came from the patient, the body does not reject them. Because these grafts are very thin (only a few cell layers thick) they do not stand up to trauma, and the "take" is often less than 100%. Newer grafting procedures combine CEA with a dermal matrix for more support. Research is investigating the possibilities of combining CEA and a dermal matrix in one product.
Experimental procedures are being tested for burn victims using stem cells in solution which are applied to the burned area using a skin cell gun
. Recent advances have been successful in applying the cells without damage.
In order to remove the thin and well preserved skin slices and stripes from the donor, surgeons use a special surgical instrument called a dermatome
. This usually produces a split-thickness skin graft, which contains the epidermis with only a portion of the dermis
. The dermis left behind at the donor site contains hair follicle
s and sebaceous gland
s, both of which contain epidermal cells which gradually proliferate out to form a new layer of epidermis. The donor site may be extremely painful and vulnerable to infection.
The graft is carefully spread on the bare area to be covered. It is held in place by a few small stitches or surgical staple
s. The graft is initially nourished by a process called plasmatic imbibition in which the graft "drinks plasma". New blood vessels begin growing from the recipient area into the transplanted skin within 36 hours in a process called capillary inosculation. To prevent the accumulation of fluid under the graft which can prevent its attachment and revascularization, the graft is frequently mesh
ed by making lengthwise rows of short, interrupted cuts, each a few millimeters long, with each row offset by half a cut length like bricks in a wall. In addition to allowing for drainage, this allows the graft to both stretch and cover a larger area as well as to more closely approximate the contours of the recipient area. However, it results in a rather pebbled appearance upon healing that may ultimately look less aesthetically pleasing.
An increasingly common aid to both pre-operative wound maintenance and post-operative graft healing is the use of negative pressure wound therapy
(NPWT). This system works by placing a section of foam cut to size over the wound, then laying a perforated tube onto the foam. The arrangement is then secured with bandages. A vacuum unit then creates negative pressure, sealing the edges of the wound to the foam, and drawing out excess blood and fluids. This process typically helps to maintain cleanliness in the graft site, promotes the development of new blood vessels, and increases the chances of the graft successfully taking. NPWT can also be used between debridement and graft operations to assist an infected wound in remaining clean for a period of time before new skin is applied. Skin grafting can also be seen as a skin transplant
Rejection may occur in xenografts
. To prevent this, the patient usually must be treated with long-term immunosuppressant
drugs.
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
. The transplanted tissue
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
is called a skin graft.
Skin grafting is often used to treat:
- Extensive woundingWoundA wound is a type of injury in which skin is torn, cut or punctured , or where blunt force trauma causes a contusion . In pathology, it specifically refers to a sharp injury which damages the dermis of the skin.-Open:...
or traumaPhysical traumaTrauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death... - BurnsBurn (injury)A burn is a type of injury to flesh caused by heat, electricity, chemicals, light, radiation or friction. Most burns affect only the skin . Rarely, deeper tissues, such as muscle, bone, and blood vessels can also be injured...
- Areas of extensive skin loss due to infection such as necrotizing fasciitisNecrotizing fasciitisNecrotizing fasciitis , commonly known as flesh-eating disease or Flesh-eating bacteria syndrome, is a rare infection of the deeper layers of skin and subcutaneous tissues, easily spreading across the fascial plane within the subcutaneous tissue.Necrotizing fasciitis is a quickly progressing and...
or purpura fulminansPurpura fulminansPurpura fulminans is a haemorrhagic condition usually associated with sepsis or previous infection. It occurs mainly in babies and small children.It was first described by Guelliot in 1884.- Presentation :... - Specific surgeries that may require skin grafts for healing to occur - most commonly removal of skin cancerSkin cancerSkin neoplasms are skin growths with differing causes and varying degrees of malignancy. The three most common malignant skin cancers are basal cell cancer, squamous cell cancer, and melanoma, each of which is named after the type of skin cell from which it arises...
s
Skin grafts are often employed after serious injuries when some of the body's skin is damaged. Surgical removal (excision or debridement) of the damaged skin is followed by skin grafting. The grafting serves two purposes: reduce the course of treatment needed (and time in the hospital), and improve the function and appearance of the area of the body which receives the skin graft.
There are two types of skin grafts, the more common type is where a thin layer is removed from a healthy part of the body (the donor section) like peeling a potato, or a full thickness skin graft, which involves pitching and cutting skin away from the donor section. A full thickness skin graft is more risky, in terms of the body accepting the skin, yet it leaves only a scar line on the donor section, similar to a Cesarean section scar. For full thickness skin grafts, the donor section will often heal much more quickly than the injury and is less painful than a partial thickness skin graft.
Graft taxonomy
- Autologous: The donor skin is taken from a different site on the same individual's body (also known as an autograft).
- Isogeneic: The donor and recipient individuals are genetically identical (e.g., monozygotic twins, animals of a single inbred strain; isograft or syngraft).
- Allogeneic: The donor and recipient are of the same species (human→human, dog→dog; allograft).
- Xenogeneic: The donor and recipient are of different species (e.g., bovine cartilage; xenograft or heterograft).
- Prosthetic: Lost tissue is replaced with synthetic materials such as metal, plastic, or ceramic (prosthetic implants).
Graft classification
Skin grafts can be:Split-thickness
A split-thickness skin graft (STSG) is a skin graft including the epidermis and part of the dermis
Dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...
. Its thickness depends on the donor site and the needs of the patient. It can be processed through a skin mesher which makes apentures onto the graft, allowing it to expand up to nine times its size. Split-thickness grafts are frequently used as they can cover large areas and the rate of autorejection is low. You can take from the same site again after 6 weeks. The donor site heals by re-epitheliasation from the dermis and surrounding skin and requires dressings.
Full-thickness
A full-thickness skin graft consists of the epidermis and the entire thickness of the dermis. The donor site is either sutured closed directly or covered by a split-thickness skin graft.
Composite graft
A composite graft is a small graft containing skin and underlying cartilage or other tissue. Donor sites include, for example, ear skin and cartilage to reconstruct nasal alar rim defects.
Donor selection
When grafts are taken from other animals, they are known as heterografts or xenografts. By definition, they are temporary biologic dressings which the body will reject within days to a few weeks. They are useful in reducing the bacterial concentration of an open wound, as well as reducing fluid loss.For more extensive tissue loss, a full-thickness skin graft, which includes the entire thickness of the skin, may be necessary. This is often performed for defects of the face and hand where contraction of the graft should be minimized. The general rule is that the thicker the graft, the less the contraction and deformity.
Cell cultured epithelial autograft (CEA) procedures take skin cells from the patient to grow new skin cells in sheets in a laboratory. The new sheets are used as grafts, and because the original skin cells came from the patient, the body does not reject them. Because these grafts are very thin (only a few cell layers thick) they do not stand up to trauma, and the "take" is often less than 100%. Newer grafting procedures combine CEA with a dermal matrix for more support. Research is investigating the possibilities of combining CEA and a dermal matrix in one product.
Experimental procedures are being tested for burn victims using stem cells in solution which are applied to the burned area using a skin cell gun
Skin cell gun
The skin cell gun is an experimental device for the treatment of second degree burns developed by Jörg C. Gerlach and colleagues at Stem Cell Systems GmbH in Berlin. With this technique, individual adult stem cells from the patient's uninjured skin are applied to the wound site, where they...
. Recent advances have been successful in applying the cells without damage.
Surgical procedure
Dermatome (instrument)
A dermatome is a surgical instrument used to produce thin slices of skin from a donor area, in order to use them for making skin grafts. One of its main applications is for reconstituting skin areas damaged by grade 3 burns or trauma....
. This usually produces a split-thickness skin graft, which contains the epidermis with only a portion of the dermis
Dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...
. The dermis left behind at the donor site contains hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
s and sebaceous gland
Sebaceous gland
The sebaceous glands are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals...
s, both of which contain epidermal cells which gradually proliferate out to form a new layer of epidermis. The donor site may be extremely painful and vulnerable to infection.
The graft is carefully spread on the bare area to be covered. It is held in place by a few small stitches or surgical staple
Surgical staple
Surgical staples are specialized staples used in surgery in place of sutures to close skin wounds, connect or remove parts of the bowels or lungs. A more recent development, from the 1990s, uses clips instead of staples for some applications; this does not require the staple to penetrate.Stapling...
s. The graft is initially nourished by a process called plasmatic imbibition in which the graft "drinks plasma". New blood vessels begin growing from the recipient area into the transplanted skin within 36 hours in a process called capillary inosculation. To prevent the accumulation of fluid under the graft which can prevent its attachment and revascularization, the graft is frequently mesh
Mesh
Mesh consists of semi-permeable barrier made of connected strands of metal, fiber, or other flexible/ductile material. Mesh is similar to web or net in that it has many attached or woven strands.-Types of mesh:...
ed by making lengthwise rows of short, interrupted cuts, each a few millimeters long, with each row offset by half a cut length like bricks in a wall. In addition to allowing for drainage, this allows the graft to both stretch and cover a larger area as well as to more closely approximate the contours of the recipient area. However, it results in a rather pebbled appearance upon healing that may ultimately look less aesthetically pleasing.
An increasingly common aid to both pre-operative wound maintenance and post-operative graft healing is the use of negative pressure wound therapy
Negative Pressure Wound Therapy
Negative-pressure wound therapy is a therapeutic technique using a vacuum dressing to promote healing in acute or chronic wounds and enhance healing of first and second degree burns. The therapy involves the controlled application of sub-atmospheric pressure to the local wound environment, using a...
(NPWT). This system works by placing a section of foam cut to size over the wound, then laying a perforated tube onto the foam. The arrangement is then secured with bandages. A vacuum unit then creates negative pressure, sealing the edges of the wound to the foam, and drawing out excess blood and fluids. This process typically helps to maintain cleanliness in the graft site, promotes the development of new blood vessels, and increases the chances of the graft successfully taking. NPWT can also be used between debridement and graft operations to assist an infected wound in remaining clean for a period of time before new skin is applied. Skin grafting can also be seen as a skin transplant
Risks
Risks for the skin graft surgery are:- BleedingBleedingBleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
- InfectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
- Loss of grafted skin
- Nerve damageNerve DamageNerve Damage is a compilation album by Groove Metal band Skinlab, released in 2004. It is a 2CD collection of rare and unreleased material, including a live set, demos, remixes, alternate mixes, and two new tracks.-Disc 1:# "Losing All" – 4:04...
- Graft-versus-host diseaseGraft-versus-host diseaseGraft-versus-host disease is a common complication after a stem cell transplant or bone marrow transplant from another person . Immune cells in the donated marrow or stem cells recognize the recipient as "foreign". The transplanted immune cells then attack the host's body cells...
Rejection may occur in xenografts
Xenotransplantation
Xenotransplantation , is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenografts or xenotransplants...
. To prevent this, the patient usually must be treated with long-term immunosuppressant
Immunosuppressant
An immunosuppressant is any substance that performs immunosuppression of the immune system. They may be either exogenous, as immunosuppressive drugs, or endogenous, as ,e. g., testosterone...
drugs.
Prognosis
Most skin grafts are successful, but in some cases they do not heal well and require repeat grafting. The graft should also be monitored for good circulation. The recovery from surgery is usually rapid after split thickness skin grafting. The skin graft must be protected from trauma or significant stretching for 2-3 weeks. Depending on the location of the graft, a dressing may be necessary for 1-2 weeks. Exercise that might stretch or injure the graft should be avoided for 3-4 weeks.External links
- Skin graft. MedlinePlus Medical Encyclopedia. Parts of this US Federal Government public domain text were used in the article.
- An introduction to the use of vacuum assisted closure.