Skin transplantation is total surgical removal or detachment of healthy skin areas (as a rule, doctor use patient’s hip, shoulder, buttock or back skin) that will be fixed on another body area. Today, this procedure is one of the most frequently used in plastic surgery.
The main aim of skin transplantation is covering of huge damaged skin areas that cannot be closed with the help of conservative therapy or usual surgical stitches. Skin transplantation is also used to treat wounds, when the process of their natural healing takes much time and is pretty risky.
These wounds usually form because of chemical burns, thermal burns, as well as chronic wounds that cannot be cured naturally.
The success of transplantation depends on the state of wound: if it isn’t infected and has good blood supply, healthy donor tissue will grow into it without problems. Practice shows that the closer is the place where the flap is taken from, the better is the transplantation from aesthetic point of view.
Most often, open wounds that cannot be cured or closed with conservative or standard surgical methods appear because of serious traumas after accidents, arterial and venous vessel diseases (most often, these defects take place near bones, for instance, an ulcer of lower limbs). Skin transplantation can also be used to treat big thermal and chemical skin burns, and skin tissue defects caused by ulcers (for instance, pressure ulcer or diabetic ulcers).
Therefore, it’s crucial to close such wounds as soon as possible, because huge open areas make it easy for bacteria to get inside, so the wound can be easily infected. Besides, human body keeps emiting protein-rich fluid inside and outside of a poorly healing would. Depending on the size of wound, it can lead to dangerous, or even life-threatening dehydration of body. In the affected areas, skin ceases performing its natural function of a natural barrier, so the tissue lying right under the skin can be easily damaged, and occurs under serious threat.
There are two widespread types of skin transplantation that are frequently used in plastic surgery: transplantation at the entire skin thickness, and transplantation of a split-thickness skin graft.
During both procedures, patients “own transplants” can be used (authentic transplants or skin areas: donor and recipient are one and the same person), or transplants from someone else’s skin (allogenic transplants: donor and recipient are different people).
The last method is used, if more than 70% of patient’s skin was damaged, e.g. his own skin is not enough to cover such a huge area.
During full transplantation, tissue flaps from the upper skin layers (upper layer, epidermis and skin, derma) together with cutaneous appendage (hair follicles, perspiratory glands, etc.) are used.
These transplants are typically very thick (0,8-1,1 mm thickness) in comparison with split-thickness skin grafts. The wound that was left after removal of a skin flap should be closed with the help of a primary stitch, so the transplants of this type can be small-sized only. As the result of the process, a scar forms in the area where the tissue has been removed, therefore, this area cannot be further used as donor one. Although this method implies slow recovery, it gives better results from the visual and functional standpoints rather than a split-thickness skin graft.
This type of transplantation is suitable for deep, but small and non-infected wounds. In case of transplantation at the entire skin thickness, the techniques of sliding (advancement) or rotary flap can be used, if healthy non-damaged skin is located near the wound to be treated. This method implies cutting a skin flap from three sides and turning it so that the contact with the donor skin would be preserved. This way, the process of blood flow restoration and wound recovery becomes much quicker.
As a rule, split-thickness skin grafts cover only epidermis and part of derma, so they are much thinner (0,25 – 0,75 mm) than full transplants.
The main advantage of this method is that the wound staying after skin flap removal totally recovers within 2-3 weeks, and one and the same area can be used as a donor flap several times in a row (in comparison with full implants, this method does not leave scars).
To remove a split skin area, surgeons use special scalpels (dermatome, Humby knife), however, to get so-called “network transplants”, doctors use a special device that cuts the removed skin in the form of a mesh. This way, the area of removed skin can be increased by 1,5-8 times allowing to cover severely damaged areas. Another advantage of split-thickness skin graft method is that it can be used to cover infected wounds and wounds poorly supplied with blood flow.
Another method of obtaining skin for transplantation is growth of new skin from separate skin cells that grow in a laboratory for transplantation specimens in artificial nutrient medium during 2-3 weeks.
During split-thickness skin graft transplantation, donor skin flap is removed in sterile surgical conditions with the help of a special dermatome of Humby knife. After that, it can be cut into a mesh with a special device to increase its surface. The place where the tissue has been obtained is cleaned and processed with haemostatic and wound-healing compounds and is closed in sterile conditions. The transplant is put on the recipient wound and fixed with a special tissue clue, clamps or small stitches.
The same sterile conditions are required for transplantation of full-thickness skin, but in this case, a usual scalpel is used, and the place for tissue removal is marked beforehand with the help of a pattern. If a full-thickness skin flap is removed, the area is degreased, and its surface is scratched with a scalpel several times to promote its better survival. The flap where the skin was removed from is stitched and covered with a sterile compression band that should be worn for 5 days.
The transplant is put the same way as during the method of split-thickness skin graft transplantation.
Both in case of full-thickness and split-thickness skin flap removal, a plastic surgeon should pay particular attention to the direction of the cut: it should correspond with the line of skin stitching to guarantee normal scarring.
Besides, it should also be considered that the transplant is cut in several places and is not fixed too tightly. It also should not be stretched too much. This is made to let the wound discharge out.
Depending on the place where the skin was removed and the damaged area where it has to be transplanted, surgery can be done either with a local anesthesia, or under a general anesthesia.
To ensure optimal recovery of transplant, the affected body part/limb should be immobilized during the first 6-8 days, and light compression pads should be applied. As a rule, plaster bandages or splints are used for that.
During 10 days, the transplant becomes overgrown with newly formed tissue and connects with the blood circulatory system of surrounding healthy skin, which ensures normal blood supply of the transplant.
This result can be reached thanks to new skin growth factors. In some cases, a tumor can form in the affected area and persist for 2-4 days (it occurs because of fluid collection or wound secretion). The color of transplant also changes as it is filled up with the blood: initially, it’s pale, but after 3-4 days it turns a bit red, in a week it becomes read and, finally, after a couple of weeks it starts matching normal skin color. Almost the same time period of required for hairs to start growing on the area of transplantation (about 2-3 weeks).
To promote the process of scarring and support elasticity of scar tissue, a patient should use some oily ointments. Besides, the movement of scarred area should be restricted: the patient should learn to move so that the scar tissue would stretch as less as possible. This way, the transplant will start taking much faster.
In comparison with foreign skin transplants, transplants from patient’s own skin are not typically rejected. Possible complications connected with transplantation of patient’s own skin or foreign skin flap can be the following: infections (as a rule, contamination with streptococcus takes place), bleeding during and after the procedure. Besides, there can be some problems with recovery, slow growth or necrosis of transplant, if the closed wound was not sufficiently supplied with blood or lost blood (hematomas formed) after the operation.
To top it off, wrong application (under stretch) or insufficient (free) fixation of transplant can contribute to poor recovery, because the contact between the transplant and the wound bottom is not optimal.
Even if the wound has healed totally, sometimes a person can undergo changes of sensation: for example, the place of transplantation can numb, or hair may grow incorrectly, or be absent at all. If the transplanted area was too big, the movement of affected limbs should be restricted depending on the localization of the scar, because scar tissue is less elastic and prone to stitching.
The risk of complications depends, from one side, on patient’s age, and from another – on concomitant diseases that can make the process of wound healing worse. Therefore, elderly patients (older than 60 years), newborn babies and toddlers, and people with such diseases as diabetes, anemia, disorders of arterial circulation, immune deficiency and chronic diseases have a higher risk of developing complications.
Besides, intake of some certain drugs (for instance, anticoagulants, immunosuppressant drugs, and cancer medication), poor nutrition and regular use of nicotine can affect wound healing or even prevent it.