Skin grafting is a surgical technique that allows the coverage of skin damage using tissue from another part of the body. Learn more about this intervention.
The skin is the organ that covers our body and serves as a barrier against the world around us. In this way, it protects us from infections and also preserves the conditions of the internal environment. Some skin lesions are so extensive or complex that they require the use of a skin graft for their treatment.
This type of surgical treatment aims to give integrity to the tissue. In this way, the underlying structures are protected and the barrier effect that the skin exerts is guaranteed. Finally, it covers not only the damage caused by the injury, but also an attempt is made to create aesthetic results. Next, let’s talk more about it.
What is a skin graft?
A skin graft consists of a skin fragment obtained through surgery. It completely separates the said fragment from some region of the body —called a donor—and then transplants it to the receiving site, that is, the site that presents damage or injury.
From the moment it is part of its donor site, the graft loses blood flow. For this reason, the receiving tissue should have the ability to provide adequate blood supply. In this way, the transplanted skin can be revascularized and, therefore, can survive in its new location.
The skin graft allows the recovery of skin barrier function in case of severe lesions.
To understand the types of existing skin grafts, it is necessary to know the histological layers of the skin. The epidermis is the most superficial layer. This structure has no blood vessels of its own and receives its blood supply from the deeper parts of the skin. Thus, epidermis-only grafts fail and are therefore not useful.
On the other hand, the deepest layer of the skin is the dermis. In turn, it is possible to divide it into two parts: the papillary dermis and the reticular dermis. The first is the most superficial layer, so your blood vessels are the ones that allow the nutrition of the overlying epidermis. Under the dermis is subcutaneous cellular tissue, rich in fat.
Skin graft types
The classification most commonly used in skin grafts responds to the thickness of the skin involved. In general, two types are accepted: partial thickness grafts and full-thickness skin grafts.
- Partial thickness grafts: the thickness is variable, but should always contain a part of the dermis. Thus, it is guaranteed the donation of the elements necessary for cell regeneration and nutrition of the overlying epidermis. According to the thickness of the dermis involved, the thickness of this tissue may be more or less thin.
- Full thickness grafts: The sectioned skin fragment contains both the epidermis and the entire dermis. The tissue should be devoid of subcutaneous fat to allow neovascularization.
According to how the skin graft is used
According to the need to cover the damage, the grafts can be continuous, that is, formed by one or more fragments that, when joined together, can cover all the loss of substance.
Similarly, there are also discontinuous skin grafts, in which the damage is not fully covered. Among them are the following options:
- Tanner and Vandeput mesh.
- Multifragmented graft.
- Graft in Trueba tracks.
- Gabarro stamps.
- Davis or gum graft.
The choice of one type of graft over another answers several questions. The location of substance loss is extremely important, as is the selection of the donor site.
Similarly, the extent of the lesion will allow considering different types of graft. Meanwhile, the cause of substance loss helps the surgeon choose the most appropriate thickness.
Characteristics of skin grafts
Depending on the thickness of the fragment, each type of graft has some advantages over the others. In addition, the injured tissue also plays an important role for the graft “pick up”, that is, for the success of the technique. Let’s describe below some of the features that need to be considered.
Donor and recipient
Since the skin has a high antigenicity, skin grafts can only originate from the person himself. This is because the immune system is not able to recognize elements other than yours. Thus, an immune response is triggered that eventually rejects the grafted tissue.
This type of transplant – in which the donor is the same individual as the recipient – is known as “autograft”. However, there are situations (such as large burns) in which the use of skin grafts from cadavers, or even pigs, has some use.
Donor tissue conditions
The choice of the place from which the skin graft will be removed should be judicious to ensure the best possible result. Therefore, fragments usually come from sites close to the lesion. In general, the following recommendations are suggested:
- Have coloring similar to the receiving site.
- In cases of tumor resection, it is advisable to choose the contralateral limb to remove the graft.
- The tissue should be free of infection.
- It is recommended that the texture and distribution of body hair between the two sites (donor-recipient) be similar.
Conditions of injured tissue
The recipient bed is the bottom where the skin graft should adhere. It must have abundant vascularity to allow the new tissue to survive. However, the presence of infections or hemorrhages decreases success rates and therefore it is necessary to treat them first.
Situations where skin grafting is useful
Although it represents a solution for complex skin lesions, not all body locations allow skin grafts to be the best option. Despite this problem, the main situations in which they are used are as follows:
- Big burns.
- Extensive wounds.
- Resection of cutaneous tumors.
- Ulcers in the lower limbs.
- Damage to mucous areas.
Skin grafts can only come from the person himself; otherwise, an immune response occurs that rejects the tissue.
Healing of the lesion
In addition to providing tissue vascularization, the receptor bed can produce retractions in the skin graft, especially if it is partially thick. Therefore, it is recommended to use full-thickness grafts in aesthetic areas such as the face, as they have better coverage and less shrinkage.
On the other hand, when substance losses are very extensive, it is more appropriate to use partial-thickness fragments, which are also discontinuous. The mesh, for example, allows to increase the size of a continuous skin graft by up to three times. This increases the cover capacity of the fragment, although it represents less aesthetic results.
Skin graft complications
As with any surgical treatment, there are some risks with skin grafting. The most common include the following:
On the other hand, retractions, scars and changes in pigmentation can affect the final appearance of the skin graft. In such cases, additional dermatological procedures may be recommended to improve the final appearance.