Overview of Skin Grafting(Archived)
Skin grafting is a method doctors use to close wounds, usually after removing skin cancer. Even though it’s not as popular as using skin flaps, skin grafting can still give a nice-looking result. Unlike skin flaps, which remain connected to a blood source, skin grafts are completely detached. While skin grafts are easier to apply, they might take more time because the doctor needs to operate on two places on the body.
Skin grafts come in different types, each having their own advantages and risks. There are three main types:
- Split-thickness skin grafts (STSG): These are made up of the top layer of skin and a tiny bit of the second layer.
- Full-thickness skin grafts (FTSG): These include the top and second layer of skin in their entirety.
- Composite grafts: These contain not only skin but also other types of tissue, usually cartilage (which is a type of firm tissue).
Full-thickness skin grafts are the most used in skin medicine. They can offer an excellent match for the recipient site and heal with minimal scarring and tightening. Composite grafts, however, can be more demanding on the body and are usually only used on the nose and ear if cartilage needs to be replaced too. Split-thickness grafts don’t usually look as good because they lack certain skin features and might not match the color of your skin. They also have a high risk of tightening. On top of that, the donor places for split-thickness grafts might hurt more than those for full-thickness grafts.
Anatomy and Physiology of Skin Grafting(Archived)
When doctors perform a graft, which is like a transplant of skin or tissue from one part of the body to another, they need to make sure that blood supply to the moved skin is good. This is important for the skin to live in its new place. Also, for the graft to look good and blend in with the surrounding area, the matching of the donor skin is key. The grafted skin and the skin from where it was taken (the ‘donor site’) should be similar in thickness, color, and texture. It should also have the same adnexal structures, which means they have similar oil glands, sweat glands, and hair follicles.
Even though it’s preferable for the donor skin and the graft area to have the same amount of sun damage or ‘actinic damage’, it’s even more important that the donor skin is free of harmful cancerous or potentially cancerous spots. And ideally, for cosmetic reasons, areas of skin that grow hair should not be moved to areas that don’t usually have hair. If hair ends up growing in the wrong place after the graft has healed, it can be removed with a process called epilation.
Common places where skin is taken for grafts on the face include areas like above the collarbone, in front or behind the ear, or the inner arm. A specific spot, called the conchal bowl (the curve inside the ear), is great for nose grafts because the skin there is oily.
For a kind of graft called split-thickness skin graft (or STSG for short), places where the skin is usually taken from include the trunk (the central part of the body), buttocks, thighs, or inner arm.
Why do People Need Skin Grafting(Archived)
In simpler terms, surgeons aim to choose the most straightforward method to close a wound that will also result in the best visual outcome. Grafts, or pieces of skin or tissue taken from one part of the body to repair another, are usually used when simpler methods aren’t good enough to close the wound.
There are different types of grafts used in different scenarios:
Split-Thickness Skin Grafts
These skin grafts are used for large wounds and can survive and successfully heal even in areas of the body with relatively low blood supply, where other types of graft would typically fail. They are typically reserved for sites that are too big for a full-thickness skin graft or a flap.
Full-Thickness Skin Grafts
These skin grafts are used for small areas that don’t have a good blood supply (less than 1 cm), or for larger areas with a good blood supply. Because they include both the top and lower layers of skin, they require more blood and nutrients to heal properly. Therefore, large grafts over bone or cartilage, which don’t have any tissue in between, may not work well. There are various options to allow for these grafts to be used successfully, like delaying the placement of the graft or using hinge flaps (a type of skin graft) to cover the exposed tissue lacking in blood supply.
Composite Grafts
Composite grafts are used when a part of your body has lost underlying muscle or bone. The most common composite grafts in skin surgery include grafts with cartilage, which are commonly used to strengthen the nose or ear.
When a Person Should Avoid Skin Grafting(Archived)
There are some situations when a skin graft, which is a type of surgery that involves moving skin from one area of the body to another, should not be done:
If the cancer has not been completely removed, if there is an active infection or uncontrollable bleeding, the doctors would advise against skin grafting. These situations pose too great a risk for a successful procedure.
There are also factors which may not completely rule out the procedure, but could make it more complicated or less likely to be successful. These include smoking, taking blood-thinning medication, having a disorder that affects blood clotting, long-term use of corticosteroids (medications that reduce inflammation), or being malnourished.
When considering the different types of skin grafts, Split-thickness grafts are not recommended for use near free margins (edges of tissue that aren’t secured to anything) because they make it more likely for the area to shrink abnormally.
Full-thickness skin grafts, on the other hand, shouldn’t be used on an area without a blood supply (avascular) that’s bigger than 1 cm. This is because the graft needs a blood supply to heal correctly.
How is Skin Grafting(Archived) performed
If you have a skin injury or defect, your doctor may recommend what’s known as a skin graft. This is a type of surgery that involves taking a piece of skin from one part of your body (the donor site) and placing it on the area that needs to be repaired. The procedure can be done in two different ways: a full-thickness skin graft or a split-thickness skin graft.
In a full-thickness skin graft, the doctor will prepare both the injured area and the donor site and then numb them so you don’t feel any pain. They’ll make a template of the exact size of the area needing the graft and then use this to cut out the correct size of skin from the donor site. The donor skin is usually made slightly larger than the damaged area to allow for some shrinking and to fit the graft in exactly. Once the skin has been taken from the donor site, it will be soaked in a special liquid and any fatty tissue removed. The graft is then quickly placed onto the wound, ensuring it fits snugly. The graft is then sewn into place with a type of special thread that dissolves over time. Finally, a special bandage is placed over the graft to hold it in securely and to prevent the area from drying out. After a week, this bandage can be removed and any remaining stitches taken out after about two weeks.
A split-thickness skin graft is a slightly different procedure. The skin is cleaned with a saline solution to remove any antiseptic and to keep the skin moist. A numbing agent is applied to the skin to prevent any discomfort. For this type of procedure, your doctor will use a special surgical instrument called a dermatome that can remove a thin layer of skin that includes the top layer (epidermis) and part of the middle layer (dermis). The doctor controls how thick the removed skin is. Once the graft is cut out, it is placed onto the injured area and shaped to fit perfectly. The graft is then fastened into place using stitches or staples and a special bandage is applied over the top. The area where the skin was taken from is then treated like a scrape or abrasion and covered with a protective ointment and a bandage.
In both cases, the surgeon will take care to make sure that the graft fits perfectly onto the wound area to reduce the risk of the graft not completely attaching.
Possible Complications of Skin Grafting(Archived)
If you have a skin graft, which is a procedure to place new skin over an area of the body, it’s good to understand the risks involved. One risk is that the graft could fail. The graph gets its nourishment from the nutrients in the area where the graft is placed. But, if the metabolic demands – or energy requirements – are too high, or if the graft gets separated from the wound, it might fail. Several things can increase this risk, like if the graft doesn’t well suit the wound, or if there’s an infection, or some unusual build-up of blood or fluid.
It’s important to know that the graph can be quite delicate and is vulnerable to breakage from any shearing or friction forces. Doctors can take steps to help prevent failure, like making sure there’s no bleeding or fluid build-up during the surgery. They can use special stitches in large grafts and make small cuts in the graft to increase its size.
If there’s any sign of a graft failing, the graft might appear very white or overly black about a week or two after the grafting. But these signs might only be indicating superficial damage, and the dermis, the thicker layer of skin beneath the surface, may still survive. So, there’s rarely a need for more removal of damaged tissue shortly after grafting.
It’s also important to note that the body might replace superficial damage with healthy tissue several weeks after grafting. Even if the graft does fail, it may still serve as a natural bandage over the wound, allowing it to heal naturally.
There’s also a greater risk of contracture – skin tightening – in split-thickness skin grafts compared to full-thickness grafts. Because of this, split-thickness grafts, which only involve the top two layers of the skin instead of all three, shouldn’t be used near the free edges of the skin.
What Else Should I Know About Skin Grafting(Archived)?
Performing the right technique when applying a skin graft can lead to successful wound healing after skin cancer removal. Though a different method called ‘flap closures’ is more popular nowadays, using skin grafts can still give a pleasing visual outcome.