Free autodermoplasty with a split skin flap. Loose skin grafting Split skin flap
Skin grafting using a split skin flap is the most in a simple way heal large wounds.
The meaning of this plasty is to use a thin 0.1-0.8 mm surface layer of the skin, which is taken with a special instrument by a dermatome. This skin flap is perforated, which allows you to increase its area several times.
After that, it is placed on the prepared perceiving wound and fixed with separate sutures.
As a result of the operation, the transplanted skin grows into the wound and closes it. The area where the skin was taken from heals on its own, as the growth part of the skin remains in place.
Advantages of skin grafting at the Innovative Vascular Center
Compared to other clinics in our country, the Innovative Vascular Center has undeniable advantages in the use of plastic surgery methods for the treatment of vascular patients. In our clinic, the closure of skin wounds and trophic ulcers is performed in a specialized department for the treatment of critical ischemia. Thus, wounds are treated by surgeons, who provide the restoration of blood circulation necessary for successful wound healing.
We are well aware of the course of wound processes in patients and we choose the necessary time and method for closing a trophic ulcer or wound for each case. To prepare wounds for skin grafting, we use methods of active preparation of the wound surface. Dressings and antibacterial drugs are prescribed taking into account the sensitivity of the wound microflora.
Thanks to innovative technologies, we manage to heal such wounds that no other clinic in our country takes on!
Preparation for skin plastic surgery
For skin plastic surgery to be successful, a number of conditions must be met. The human body must be stabilized in terms of blood, protein synthesis. It is necessary to stop the infectious process. Conditions for skin grafting should be local:
- Good bleeding edges of the wound, active juicy granulation.
- The wound is in the granulation stage (without signs of active infection and purulent inflammation).
- The wound must be well supplied with blood (circulation must first be restored).
- The wound must be cleaned of dead tissue using physical and chemical methods.
General conditions for skin plastic surgery:
- The level of protein in the blood should be at least 60 g / liter.
- Hemoglobin level not less than 90 g/liter.
- The patient must be stabilized in general condition
Immediate preparation for surgery involves shaving the site of skin flap sampling, catheterization Bladder installing an epidural catheter for anesthesia.
Anesthesia
During operations on the extremities, epidural or spinal anesthesia is mainly used. Their advantage lies in the local effect on the body. Epidural anesthesia allows prolonged pain relief in the postoperative period.
In order to control the functions of cardio-vascular system a special monitoring monitor is connected to the patient.
How is the operation
The patient is placed on the operating table so that there is good access to the wound. After processing the surgical field and closing the operation area with sterile sheets, surgical treatment of a trophic ulcer or wound is performed. During this treatment, all remaining necrotic tissue areas are removed and pinpoint bleeding from the granulations is provided.
After that, a split skin flap is taken. A saline solution is injected into the thickness of the skin, which lifts the skin itself and facilitates its separation. After creating such a "water cushion", the flap is taken using a special tool - an electrodermotomy. This is a special circular knife, which is set to a certain thickness of the required flap. After that, the razor of this dermatome removes the thinnest skin flap of the right size.
To increase the area of the skin flap, it is passed through a special tool - a perforator. The perforator in a checkerboard pattern makes small cuts on the flap. Now the flap, when stretched, can cover an area several times larger than its original one.
After perforation, the flap is placed on the wound surface and modeled according to the shape of the wound. In order to fix it, it is sutured with the thinnest sutures to the edges of the wound and pressed with a pressure bandage.
The donor site is closed with a bandage with an antiseptic.
Features of the postoperative period
The first dressing after flap transplantation is preferably done 2-3 days after the operation. During this time, most of the flap adheres to the granulation tissue and does not come off when the dressing is changed. In any case, the dressing should be changed very carefully, removing it in layers with a tool.
During dressing, fixation of the transplanted flap to the granulations is noted, and non-adhering pieces of skin are removed. If a local infection is noted, then sowing is taken and dressings with antiseptics are used.
Donor wound can not be opened if there are no signs of infection. It is enough to change the bandage on top. Over time, the skin epithelializes and the bandage will come off by itself. Usually 14 - 21 days after surgery.
Prognosis after skin plastic surgery
If the operation is performed according to indications, provided that the causes of necrosis and trophic ulcers are eliminated, then the results of skin plastic surgery are very good. Correctly performed operation ends with success in 95% of cases. In the postoperative period, the transplanted skin is gradually replaced by its own epidermis, which manifests itself in the appearance of small crusts, under which young skin is visible.
Autodermoplasty may be the definitive method of wound closure if the wound is not located on a supporting surface or in the area of a large joint. In such places, young skin can be damaged by stress with the formation of trophic ulcers. For supporting and bone surfaces, it is better to use full-layer skin grafting with flaps on a vascular pedicle.
Observation and treatment in the postoperative period
The operating surgeon must observe the patient until the complete epithelialization of the trophic ulcer or wound on which the skin was transplanted.
In the postoperative period, drugs may be prescribed that reduce the process of scarring of the skin in the plastic area. These ointments (Contratubex) can be rubbed into the wound for 3-6 months and contribute to the formation of a soft tender scar.
The final outcome of the skin graft operation depends on the course of the vascular disease that caused the formation of a trophic ulcer or necrotic wound. Therefore, the main observation is carried out over the results of the vascular stage of treatment.
The purpose of skin plastic surgery is to restore the continuity of the skin, improve appearance parts of the body, as well as preventing the formation of rough scars at the site of skin defects.
With free skin grafting, the graft (transplanted skin fragment) is completely cut off from the donor area (the place where the graft was taken).
Types of free skin grafting:
1. Plasty with a full-thickness skin flap - the skin is used as a graft for its entire thickness.
2. Plastic surgery with a split skin flap - the epidermis is used as a graft.
With non-free skin grafting, the graft is not completely cut off from the donor area. The graft in this type of skin grafting is usually called a flap.
Types of non-free skin plastics:
1. Plasty with local tissues - nearby tissues are sutured over the defect.
2. Plasty with a flap on a feeding leg - a flap is formed, which replaces the defect.
Features of types of skin plastics.
Free skin grafting with a full-thickness flap.
With this type of skin grafting, the skin in the donor area is not restored. There remains a defect that needs to be sutured (the so-called "donor wound"). Areas of the body with movable skin are chosen as donor zones, where the defect can be sutured without tension. For example, a section of the thigh or anterior abdominal wall. In addition, this significantly limits the size of the graft.
The skin of the selected area, for the convenience of cutting, can be injected with saline or 0.25-0.5% novocaine solution. Given that during healing, cicatricial wrinkling occurs along the stitching line, the graft should be 1/4 - 1/5 more than the defect. The graft is placed on the skin defect and sutured along the edges with separate sutures. In some cases, it is necessary to increase the size of the graft. To do this, the graft is perforated - through parallel notches are made, arranged in a "staggered" order, and stretched. In addition, perforation improves the outflow of wound discharge from under the graft.
Free skin grafting with a split flap.
With this type of plastic surgery, the skin in the donor area is restored. This is due to the fact that after the graft is taken, fragments of the epidermis capable of regeneration remain in the mouths of the hair follicles and sebaceous glands. They are also preserved in the thickness of the skin, due to the folding of the epidermal-dermal junction (the so-called "dermal papillae"). Consequently, with plastic surgery with a split flap, it is possible to fence significantly more about larger transplants.
As donor zones, areas of the body with a small curvature and relatively large areas skin (thighs, anterior abdominal wall). If necessary, it is possible to use other areas of the body as donor zones.
The thickness of the split graft is 0.2-0.4 mm. For its fence, special knives or special dermatome tools with manual or mechanical drive of the blades are used. Sewing of the graft along the edges is optional. If necessary, the graft is perforated and stretched.
Non-free skin plastic.
When plasty with local tissues, the resulting tension is eliminated by relaxing incisions (for example, Y-shaped).
Types of plastic surgery with a pedicle flap:
1. With the formation of a flap close to the defect - for example, plastic with oncoming triangular flaps of the Limberg type.
2. With the formation of a flap at a distance from the defect:
a. " italian way» rhinoplasty - with replacement of the defect of the tip of the nose with soft tissues of the shoulder;
b. plastic surgery of the soft tissues of the fingertip with temporary sewing it into the soft tissues of the palm - the so-called. palmar plasty of the fingertip);
c. plastic stalk flap according to Filatov.
A stalk-like flap in the form of a "suitcase handle" is formed from the skin and subcutaneous adipose tissue. One end of the flap replaces the defect. The other end is periodically clamped (so-called "flap training") to develop blood circulation at the site of the closed defect. In the future, the flap is finally cut off and moved to the defect;
d. Plasty with an "island" flap - the feeding leg of the flap is dissected, leaving only blood vessels in its composition, which increases the length and direction of flap movement.
General issues. Question 12.
Thin split skin flaps (according to Thiersch) consist of the epidermis and the papillary (its upper part) layers of the dermis. Widely used to replace defects in the mucous membranes of the mouth and nose, eye sockets. In such cases, skin grafts are performed on hard liners with STENS or soft liners with iodoform gauze. The thermoplastic mass (wall) is preheated in hot water and with moderate pressure fill the wound (cavity) with it, press it against the wound walls. After the wall hardens, a skin flap is applied to the STENS epithelium on its surface facing the wound walls and fixed on it with glue. The piece of skin is close to the wound surface. The liner is fixed in a stationary state and removed only after 8-12 days.
With a smooth course of the postoperative period, thin skin flaps take root in 7-8 days. At first, the flap has a pale, dry, parchment-like appearance. In the future, the seedling becomes more pink and fatter, and the edges of the flap passing to the adjacent tissue are smoothed out. The downside of using a thin piece is that these pieces subsequently tend to wrinkle, which occurs as a result of scarring of the tissue that is under the flap.
Pain and tactile sensitivity in the transplant begins to recover after 1-2 months. (first along the edges, and then in the center) and completes its recovery after 5-6 months. (depending on the size of the flap). Under the influence of pressure, trauma or temperature effects, these pieces can crack and ulcerate, and later become infected and melt.
Medium and thick split skin flaps are used to replace defects in the mucous membranes of the mouth and nose, the skin of the eyelids, with scalped wounds, as well as for the temporary closure of large infected wounds in seriously ill patients or in the presence of granulating wounds, granulating (on the face, head and neck) . In other cases, a two-stage (delayed) skin grafting is used. First, the wound is prepared for skin grafting: antiseptic treatment of the wound surface, ointment dressings are applied, dressings with hypertonic sodium chloride solution, and excess granulations are sometimes cauterized with 25% silver nitrate solution (not desirable). After the wound is covered with fine granulations, it is closed with a free skin graft. Seedlings are sutured to the epithelium of the edges of the wound or to the underlying tissues.
Transplanted skin flaps always undergo contraction, which causes secondary deformities. Donor wounds are covered with a layer of dry gauze, fibrin film and are not bandaged until complete healing under the bandage.
Full-thickness skin grafting is the most complete zamiitsya there is no skin cover. The transplanted flap retains its normal coloration and mobility, the function of the sebaceous and sweat glands, as well as hair growth, are restored to shreds (A.S. Yatsenko, 1871). A seedling with full-skinned skin is most sensitive to unfavorable conditions that may occur during its transplantation. Povnosharovi shreds take root well on connective tissue, fascia and muscles, and on loose fiber, ham, bone and granulation tissue, these seedlings often do not take root.
The disadvantage of the method is that the wound on the donor area after excision of the piece does not self-epithelialize and must be sutured. Technically, the excision of a globular skin flap consists in the fact that a sample of a seedling is cut out in shape on a washed X-ray film and placed on a donor site. Excision of the skin is carried out with a scalpel. The skin is dissected along the contour of the template to the subcutaneous loose tissue. With the help of tweezers, the lower edge or corner of the flap is raised and with the movements of the scalpel that they saw, the skin is cut off from the subordinate subcutaneous fatty tissue. The graft, transferred to the receiving bed, is straightened and fixed first with guiding sutures, and then the final interrupted sutures are applied, with the help of which the edges of the wound and the seedling are tightly compared. The operation is completed with the application of an aseptic bandage, moderately presses. The first dressing is carried out not earlier than on the 7-8th day after the operation. When transplanting the flap to granulating wounds on the 3-5th day after the operation, the state of the graft should be checked. In the presence of a hematoma or purulent exudate (hematoma suppuration), the seedling is perforated to evacuate the contents, treated with antiseptics and bandaged again.
Skin reimplantation is performed after the appearance of scalped wounds with complete separation of a large skin flap or in the presence of a “narrow bridge” of skin and soft tissues between the wound and the flap. It may be more common in the area of the protruding parts of the face and scalp. If this "bridge" does not contain nutrient vessels, and the skin flap has not undergone significant damage, then healing occurs, as with a free transplantation of a full-thickness flap.
F. Burian (1959) believes that the transplanted skin during the first 24 hours or more takes nutrients from its own base. After completion of 24-48 hours, the thin blood vessels of the recipient bed begin to sprout to the vessels of the transplanted graft. The transplanted skin flap should be in a new place in a state of a certain tension, the value of which should be equal to the skin tension at the primary site of the graft, since when the piece is reduced, the lumen of the crossed vessels decreases or closes. However, all transplanted skin flaps receive nutrients from the recipients of the zone also by their diffusion into the flap, so it is not always possible, when necessary, to keep the hair follicles alive in a full-ball shred.
To improve the trophism of the globular Kapto skin and preserve hair follicles in it in order to create, for example, eyebrows, the globular flap is thinned, removing the upper layer of the epithelium on it, then the recipient bed is prepared without excision of the skin, but by spreading it to the sides, then a thin globular graft is fixed in the right place and close it from above with the divorced edges of the local skin. Thus, the full-faced skin graft receives nourishment from all sides, which makes it possible to more reliably preserve living hair follicles in it. 10-14 days after the transfer of the globular flap, the local skin above it is excised, which opens the transfer flap.
Skin transplantation with Janelidze. The skin flap is cut out with a U-shaped incision, its length should be equal to the length of the defect, and the width should be at least half the size of the skin defect. Gradually, a piece is cut off from loose fiber and wound onto a Kocher clamp. Then the flap is untwisted in the opposite direction, small staggered incisions are made in shreds, which allow the flap to stretch, and after that the flap is completely cut off from the donor zone. The edges of the skin along the border of the defect are mobilized with additional incisions, they are brought together and a skin flap is taken and applied to the wound, after which the wound is sutured.
However, this method is practically not used on the face due to the inappropriate provision of the cosmetic effect of the intervention.
Conditions necessary for successful free skin grafting:
asepticity of the place of plastic surgery and the donor site;
careful preparation of the bed (complete hemostasis, excision of scars to the full depth, alignment of the wound surface, etc.);
removal of loose subcutaneous tissue from the flap, prevents contact of the skin flap with the wound and delays their adhesions (grafts that are transplanted into the oral cavity should be as thin as possible, that is, without connective tissue);
correct formation of the skin seedling (should be of the same thickness over its entire area, taking into account its subsequent reduction, respect for the graft, correct selection of the donor site, etc.);
take into account the presence of hair growth on the skin of both the donor and recipient beds;
correct placement of the skin sapling on the receptive bed (careful collision of the edges of the graft and the wound, moderate and uniform stretching of the sapling)
ensuring local rest and tight contact of the skin graft with the wound surface of the receiving bed during the entire period of engraftment of the seedling by applying a bandage and ensuring complete functional rest of the operated tissues for 10-14 days.
Free skin grafting on the face and neck requires careful planning and adherence to the rules of surgical technique. Abundant blood supply to the soft tissues of the maxillofacial region, on the one hand, can ensure good engraftment of the graft, and on the other hand, contribute to the development of a hematoma located under the seedling and worsen its nutrition. There is a possibility of infection due to the proximity of the mouth and nose.
The mobility of the tissues of the oral area and the face as a result of contraction of the masticatory and facial muscles (eating, breathing, speech, facial expressions) require rest and close contact of the seedling with the wound surface of the bed during the entire period of engraftment of the skin graft.
Biological basis and results of free skin grafting
In a freely transplanted skin autograft, regular restructuring processes occur, in which three periods are distinguished: adaptation to new conditions of existence, regeneration and stabilization.
The period of adaptation to new conditions of existence lasts two days; at the same time, avascular nutrition of the transplant takes place (due to osmosis of nutrients); the epidermis and papillary dermis are necrotic.
The beginning of the regeneration period coincides with the beginning of graft revascularization, which is noted already from the 3rd day and continues until the end of the 2nd, and sometimes even the 3rd month. The regeneration period ends with the restoration (in general terms) of the structures characteristic of the skin. Active regeneration processes take place between the fifth and tenth days.
The period of stabilization of the skin graft begins from the 3rd month after transplantation and is characterized by a slow course of recovery processes, improvement of the organ characteristics of the skin, since as a result of transplantation regeneration, complete restoration of all its organ structures is not achieved.
Between the described periods there is a direct relationship. The depth of necrosis of parts of the skin graft during the adaptation period is reflected in the completeness of transplantation regeneration, the imperfection of which, in turn, delays the time for the skin graft to reach its final structure in the stabilization period.
The split skin seedling contains the epidermis, the entire papillary, and part of the reticular dermis. Depending on the content of a greater or lesser part of the reticular layer of the dermis, split skin seedlings are divided into thick skin seedlings approaching in their properties to full-layer skin seedlings, skin seedlings of medium thickness and thin skin seedlings containing the epidermis and the most superficial areas of the papillary dermis.
The skin, restored by free transplantation of split skin seedlings, differs from normal skin in color, less elasticity, and mobility. Such skin after engraftment is prone to
some wrinkling, less resistant to mechanical stress. Under it, the layer of subcutaneous fatty tissue is not restored. At the same time, split skin seedlings can be transplanted into any uncovered tissue, if they are viable. The best soil for engraftment of such flaps are subcutaneous adipose tissue with a small amount of fat, fascia, muscles, granulations; worse, split skin seedlings take root to the subcutaneous adipose tissue with a large amount of fatty elements, tendons, and the cortical plate of the bone. Wound surfaces remaining after excision of split skin seedlings are epithelialized independently without the use of additional plastic techniques within 2-5 weeks. This allows the use of such flaps of any required size.
Greater resistance to unfavorable conditions of free grafting and better engraftment compared to full-thickness skin flaps contributed to the widespread use of split skin seedlings when replacing skin defects in both emergency and elective surgery.
Free transplantation of split skin seedlings is indicated if it is necessary to close large wound surfaces during the primary surgical treatment of wounds with loss of integumentary tissues, at the stages of treatment of thermal lesions, purulent wounds. In elective surgery, the need for free transplantation of split skin arises when extensive scar surfaces are replaced, skin is transplanted onto scar, trophically altered tissues.
On the face, skin flaps containing 80-50% of the skin thickness can be used in cases where there are contraindications to the transplantation of full-layer skin seedlings. Indications for the predominant use of split skin seedlings arise only when the skin of the eyelids is restored and, if necessary, the replacement of defects in the mucous membranes of the oral cavity, nose, orbit, etc.
The less favorable the conditions for engraftment, the thinner the skin seedling should be used for transplantation. Thin skin flaps containing less than 50% of the skin thickness should be used to temporarily close large infected wounds in critically ill patients. The formation of the bed should be carried out, guided by the same rules as in plastic with full-thickness skin flaps. Exposed tendons, fascia, periosteum, bone must be tried to close with surrounding soft tissues. In the absence of such an opportunity, a split skin flap can be transplanted onto the listed formations. In the cortical plate of the bone, it is first necessary to make a lot of notches with a bur or other instrument before the appearance of capillary bleeding. Careful hemostasis is essential
When epithelializing granulating wounds with an area of 500-1000 cm 2, it is advisable to preliminarily completely excise the granulations. With wounds of a larger area, skin plasty should be preceded by only partial excision of non-viable infected granulations. Fine-grained, pink, low-bleeding granulations are good ground for split skin grafting. The exact correspondence of the shape and size of the skin seedling to the wound bed is necessary only for plastic surgery of facial defects. In this case, all the arguments indicated in the section on plastics with full-thickness skin seedlings are valid. When determining the size of the flap, it is necessary to take into account the contraction of the skin that occurs after its engraftment. Excision of split skin flaps is possible on any part of the human skin. The following sections are most convenient: the outer surface of the shoulder, the outer, inner, front and back surfaces of the thigh, back, buttocks, abdomen, chest. It is not advisable to cut the skin from areas that are functionally important, from the feet, hands, the area of large joints, mammary glands, cabbage soup. If possible, you should refrain from simultaneously cutting the skin on the back and front surfaces of the body, as this complicates the management of the postoperative period and worsens the well-being of patients. If necessary, repeated excision of split skin seedlings from healed donor sites is permissible, which is possible already 3-4 weeks after the previous operation.
In case of skin grafting during primary surgical treatment of wounds or during epithelialization of granulating surfaces, it is preferable to excise skin seedlings first, and then proceed to the treatment of infected wounds. In a planned skin graft, the operation usually begins with the formation of a bed, and then the required skin sapling is excised. Split skin flaps of relatively small size (up to 100 cm 2) can be cut manually with a scalpel. Conduct local anesthesia. In this case, soft tissues should be infiltrated with weak anesthetic solutions or isotonic sodium chloride solution until a dense “cushion” is formed with a smooth surface that rises above the surrounding skin. The borders of the future skin seedling are applied to this area, according to the drawing, the skin is cut with a scalpel to the deep layers of the dermis or subcutaneous fatty tissue. The edges of the wound begin to gape, as a result of which the area of \u200b\u200bthe skin to be excised, limited by it, rises somewhat above the surrounding tissues. This allows you to split and excise the intended area of the skin of a given thickness and shape with a dangerous razor, without damaging adjacent areas. It is useful to moisten the razor blade with isotonic sodium chloride solution. Excision of the skin is performed with smooth sawing movements. Donor wounds are covered with a layer of dry gauze, fibrin or antiseptic film and are not bandaged until complete healing under a bandage. Wounds of small sizes can be sewn up tightly after preliminary excision of the remaining deep layers of the skin. When transplanted to wound surfaces and granulation of large split skin seedlings, they are usually perforated; the exception is skin transplanted on the face. Seedlings are sutured to the edges of the wounds with rare sutures. If the tissues in the region of the edges of the wounds are loosened and bleeding, skin flaps can be placed on the wound with overlapping edges and pressed to the bottom and edges with gauze balls without additional fixation with sutures. This prevents bleeding from the needle injection sites and blood flow under the transplanted flap.
When using skin flaps containing 2/3 of the skin thickness in elective surgery, the technique of suturing seedlings to the edges of the wound and applying dressings do not differ from those when transplanting full-thickness skin flaps. When transplanting skin on the lower lip, cheeks, cartilaginous part of the nose, it is advisable to use an intraoral splint, plugs with a support platform, and tubes.
When transplanting split skin on the upper eyelids, the technique of suturing the seedling to the edges of the wound with frequent horsehair sutures can be used, followed by applying a bandage of finely chopped gauze soaked in a solution of rivanol. Another method is also used. An imprint of the wound bed is made from the dental impression mass of the Stent. The skin flap is glued to the liner with glue and placed on the wound. If desired, the skin flap can be sewn to the edges of the wound with several sutures. A soft bandage is applied on top. The use of a hard plate of impression mass makes it easier to hold the eyelid in a straightened state.
When transplanting the skin into defects of the mucous membranes, an impression of the wound is also made from the impression material. The seedling is glued to the liner and injected into the wound. Soft bandages are used to secure the graft and the liner. When transplanting skin into the oral cavity, a prefabricated plastic splint with a balcony is used to prevent displacement of the graft and insert, and a soft bandage that holds the lower jaw in a fixed position. In the nasal passages, the skin is transplanted on tubes or stent liners.
Within 6 days after transplantation of split skin, patients observe bed rest, eat liquid food. In the absence of indications, the first dressing is carried out on the 6-7th day, all dressings are removed, the sutures are removed. In the postoperative period, the same means are used as in the transplantation of full-thickness skin flaps. When restoring the skin in the neck, flexion surfaces of the joints after their cicatricial contractures, secondary wrinkling of the tissues straightened during the skin grafting operation is possible. to do therapeutic exercises. After engraftment of the skin seedling in the oral cavity, the liner made during the operation should, if necessary, be reduced, paraffinized and worn for at least 3 peds after transplantation. Then the patient must be prosthetized.
To ensure the success of reconstructive interventions in repairing skin and soft tissue defects, the surgeon must have an in-depth knowledge of the anatomy and physiology of skin grafts and local flaps. They provide the necessary understanding not only of which replacement material should be chosen (skin; skin with subcutaneous tissue or their complex, which also includes the underlying cartilage or bone), but also what properties the planned graft or flap should have (contour, color, character). blood supply, the presence of sebaceous hair units).Accurate consideration of this information allows you to develop a reasonable surgical plan. In many cases, preoperative planning is much more difficult than surgery. This chapter provides an overview of the anatomy and physiology of skin grafts and local flaps, with a focus on the evaluation and aesthetic closure of facial skin and soft tissue defects.
SKIN GRAFTS
A skin graft is an island of epidermis and dermis surgically separated from the donor site; its blood supply is transferred and further dependent on the recipient area.
There are split and full-layer skin grafts.
Split skin grafts
Split skin grafts (RKT), also known as Thiersh grafts, are usually harvested with a dermatome or razor blade. They consist of the epidermis and the superficial (papillary) layer of the dermis. Thin RCTs can be 0.02-0.025 cm thick, while thick (standard) RCTs are 0.04-0.045 cm thick. The thickness of the epidermis and dermis depends on the location on the body, skin color, age, and is usually greater in males. gender. The skin of an adult is 3.5 times thicker than the skin of a newborn. The thickness of the skin in a child at the age of 5 years approaches that of an adult.
Measurements of the thickness of the epidermis and dermis showed that it ranges from 0.04 cm to 0.36 cm in different age and sex groups, and also depends on localization. The skin of the eyelids is the thinnest and the skin of the soles of the feet is the thickest. Although CTs are widely used, they are of limited use in facial reconstructions due to their shrinking tendency.
The thinner the graft, the greater the degree of its reduction, but also the higher the likelihood of its engraftment.
Split skin grafts are usually lighter in color, have a different texture, and are thinner than adjacent skin. To increase the surface area of the CT, small incisions can be applied, but this further thins the graft and may worsen the aesthetic result. In facial reconstructions, CT is used to close large ICH defects, as well as defects associated with excision of tumors with a high degree of invasion or indefinite borders, when constant postoperative monitoring of the excision zone is especially important.
Full thickness skin grafts
When forming a full-thickness skin graft (PCT), the epidermis and dermis are separated from the donor site to the full thickness and then transplanted to the defect area. To obtain a transplant of the desired thickness, the subcutaneous layer from it can be cut off. The hair follicles are preserved so that hair growth can resume.
Full-thickness skin grafts do not shrink, change color or structure. These grafts are thicker than CT, they revascularize more slowly, and their rejection rate is higher. To ensure engraftment of the graft, a full blood supply to the recipient bed is required.
Full-thickness skin grafts are more resistant to vertical loads than CT. Donor sites for PCT are the skin of the parotid region, the supraclavicular region and, sometimes, the buccal labial fold. The PCT donor site does not have epidermal elements that can become a source of epithelialization, so it must be sutured initially or the PCT should be closed. Full-thickness skin grafts are particularly good for covering facial defects involving the tip of the nose, the lateral surface of the pinna, and the eyelids.
Dermal grafts
Dermal grafts are formed from the dermis after the overlying epidermis has been separated. These grafts are very reliable, resistant to infection and can sink under the surface of the skin.
With such recession, the epidermal elements atrophy and become inactive; however, an exposed graft or graft used superficially may re-epithelialize. Dermal flaps are used to close defects in the oral cavity or for subcutaneous implantation in order to increase the volume or change the contour. Currently, many plastic surgeons replace dermal flaps with an official fat-free dermal graft (Alloderm, LifeCell Cogr, USA), using it to increase volume or change the contour in various facial defects.
Vascularization of skin grafts
Both CT and PCT are types of free tissue grafting from the donor to the recipient site, where education is required. new structure blood supply. Revascularization of skin grafts goes through several phases: imbibition (impregnation), revascularization and organization.
Serous Impregnation Phase
The initial phase of serous impregnation or plasma circulation lasts about 48 hours. The nutrition of the graft depends on the perspiration of plasma from dilated capillaries into the receiving bed. Fibrinogen-free serum, not plasma, permeates the graft, nourishing it. Erythrocytes penetrate the fibrin clot and passively accumulate in the serum under the graft, being the source of its edema. As revascularization proceeds, new blood flow replaces the plasma-like fluid in the graft.
Phase of revascularization
Vessel rudiments begin to grow into the supporting fibrin network in the first 48 hours. Revascularization is carried out due to both direct ingrowth of the blood vessels of the maternal bed into the graft (neovascularization) and the formation of anastomoses between the vessels of the graft and the bed (fusion). Although fusion of the bed and graft vessels occurs, the primary mode of revascularization depends on the ingrowth of the bed vessels into the dermis of the graft. Lymphatic circulation between the graft and the maternal bed begins between the fourth and fifth days after the operation.
Organization phase
The organization phase begins 5 hours after transplantation. A fibrin clot is formed at the border between the graft and the bed, which also contributes to the adhesion of the graft to the maternal surface. Leukocytes begin to infiltrate the deep layers of the graft; as they revascularize, they are replaced by fibroblasts. By the seventh or eighth postoperative day, fibroblast infiltration of the fibrin clot continues as the collagen matrix is created. By the ninth day, the graft is tightly fixed thanks to the new circulatory system and the work of fibroblasts. Within 2 months, the regeneration of nerve structures begins, which are introduced into the graft from the base and on the sides, following the absorbable neurilemmocytic membrane. Skin grafts rarely acquire normal sensory innervation after engraftment.
Donor plots
When choosing a donor site for CT, the surgeon must consider a number of factors. These include: the characteristics of the donor skin (color, structure, thickness and blood supply), the amount of skin required, the need for hair on the graft, the convenience and the possibility of deformation. Most donor sites on the head and neck have an excellent blood supply; however, various other donor sites are used to provide a variety of skin color, texture and thickness. good places for the collection of skin grafts are the parotid region, upper eyelid, buccal-labial fold, as well as the supraclavicular region and abdomen.
The skin of the parotid region is thin, devoid of hair and has a structure and color suitable for the face. Here you can take the PCT and use it to replace the defects of the nose and cheeks. This donor site usually allows primary closure of the defect. A full-thickness skin graft from the skin of the upper eyelid can be taken from patients with excess skin in this area. Such a flap may be useful for closing defects of the contralateral eyelid, auricle, nasal vestibule, and external auditory canal. To ensure symmetry, the skin of both upper eyelids should be excised. This donor site gives a limited amount of skin and requires primary closure of the resulting defect. Large PCT can be obtained from the supraclavicular region or from the abdomen.
A full-thickness skin graft from the bucco-labial fold is conveniently used for the reconstruction of skin defects in the nose. The color, structure and thickness of this skin make it suitable for repairing nasal tip defects. The buccal-labial donor site can be closed initially, leaving an inconspicuous scar. Combined (skin and cartilage) flaps can be taken from the outer ear to reconstruct defects in the margin of the nose or the contralateral ear. The anterolateral thigh and abdomen are large areas for CT and dermal grafts. Full-thickness skin grafts from these areas do not match the face well in color and texture.
Surgical technique
Typically, a scalpel, electric or pneumatic dermatome is used to harvest skin grafts. Pneumatic dermatomes Brown (Brown) and Zimmer (Zimmer), as well as electric dermatome Paget (Padget) are ideal tools for obtaining continuous homogeneous skin grafts. The donor site is treated with a bactericidal solution and dried. A thin layer of mineral oil is applied to the skin of the donor site and the dermatome blade. With the help of Brown or Paget dermatomes, flaps with a thickness of 0.025-0.045 cm can be obtained.
The dermatome is positioned at an angle of approximately 45° to the skin of the donor site and is activated prior to contact with it. The skin of the donor site, as the dermatome advances, is gently stretched with a uniform force. This technique ensures that a good graft is harvested. In this case, bleeding from the dermal capillaries of the skin of the donor site will be noted. Before fixing the final dressing, to ensure temporary hemostasis, a fluoroplastic tissue impregnated with a solution of adrenaline at a concentration of 1:50,000 is applied to the donor site.
The donor site should be covered with some kind of semi-permeable coating such as Opsite or a piece of Xeroform followed by a pressure dressing such as Kerlix or Ace. Re-epithelialization of the donor site occurs within 2-3 weeks. When the skin graft is harvested, a strip of split skin (0.03-0.04 cm) is lifted as described, but left attached at one end. The strip of dermatome dissection should be narrowed so that a strip of dermis (0.03-0.035 cm) can be excised. The split skin graft is placed over the defect and fixed to the bed with sutures or staples. Preparation of the receiving bed is important to ensure graft engraftment. It should include achieving adequate hemostasis, removal of necrotic and infected tissues. Fixation of the graft to bone or cartilage that is not covered by the periosteum or perichondrium should be avoided as it does not create a well-perfused bed.
The split skin graft can be meshed in a special device, which will increase its surface area and allow the outflow of serous fluid from the area of reconstruction. Unfortunately, mesh grafts become thinner, contract more frequently, and engraft as smooth, thin, atrophic skin. If a flap of the appropriate size is formed, multiple small notches (5-6 mm) can be made in it with a scalpel, which will allow the serous fluid to drain from under the graft. The graft can be fixed to the bed with sutures or staples. Most an important factor The success of the RCT transplant is its immobilization and pressure from above.
This prevents the graft from migrating and thus limits the tensile forces on the flap that tend to break any newly formed vascular connections. For additional hemostasis and fixation of the graft to the receiving bed, fibrin glue can be used. The pressure gauze bandage is held in place by tying the ends of the skin sutures over it. Sometimes a stent can be used to put pressure on the graft in the ear or hard palate. Dressings are usually removed after 7-10 days.
Skin grafts can be stored at low temperatures. The grafts are wrapped in gauze soaked in Ringer's lactate solution or saline and stored in a sterile container at +4°C. The graft should under no circumstances be completely immersed in isotonic saline to avoid maceration. After 14 days of storage at a temperature of +4 °C, the respiratory activity of the skin graft is reduced by 50%.
SKIN FLAPTS
The skin flap consists of skin and subcutaneous tissue, which moves from one part of the body to another, being connected to it by a vascular pedicle, specially preserved for the blood supply of the flap. The relationship between the vascular pedicle and the flap can vary depending on the orientation of the defect and the flap. In some cases, it can cross and move to a distant area by microvascular anastomosis with recipient feeding vessels (microvascular free flap). Free microvascular tissue transport can be applied to fascia, skin, or a combination of skin, muscle, and bone.
Wounds and defects can be closed with a skin graft or skin flap. Although the use of a skin graft is the first consideration, there are many circumstances in which blood-supplied flaps are required. For example, when the receiving bed is poorly supplied with blood and is unable to nourish the free skin graft, or when the flap is better matched in color and texture. When planning the reconstruction of a facial defect, the surgeon must take into account its location, the visibility of this area and the patient's opinion regarding the final aesthetic result. Some special situations concern the resection of tumors with a high risk of recurrence or when the boundaries of the required excision are not clear. In such cases, it is recommended to use temporary CT to be able to constantly monitor for possible recurrence. If no recurrence occurs after a sufficient observation period, the defect can be reconstructed with a suitable flap.
Vascular anatomy of the skin
Before using local flaps for reconstruction, it is necessary to understand the anatomical variants of the blood supply to the skin. The skin is supplied with blood from two main vascular sources: the musculocutaneous vessels and the cutaneous vessels directly. Musculocutaneous vessels originate from segmental vessels; they anastomose with the axial vessels located under the muscles.
From the vessels of the muscles, perforating musculocutaneous branches originate, which penetrate the subcutaneous tissue. They provide the main blood circulation in the skin, especially on the trunk and limbs. After penetrating into the deep layers of the reticular layer of the dermis, these vessels give branches to two horizontally located microvascular plexuses of the dermis. A deeper plexus, which is located between the dermis and subcutaneous fascia, supplies blood to the skin appendages, hair follicles, and sweat glands. The processes of this deep plexus anastomose with the vessels of the superficial plexus located in the papillary
dermis layer.
Segmental vessels, anastomoses and axial vessels also give rise to a certain number of directly dermal vessels lying above the muscular fascia parallel to the skin. These arteries provide additional blood flow to the skin. Blood from the skin arteries flows into the saphenous veins, connected by a communicating vessel. Directly, the cutaneous arteries give branches to the two microcirculatory plexuses of the dermis and provide the main blood circulation in the ICH and facial skin.
Flap planning
Arbitrary patches
Arbitrary or free-form flaps (local skin flaps) are the most common type of flap used to reconstruct skin defects of the head and neck. They are created by preparation at the level subcutaneous fat. Their arterial blood supply is carried out by perforating musculocutaneous vessels of the base of the flap, coming from segmental vessels lying under the muscle and subcutaneous layer. Blood flow in the free part of the flap is provided by anastomoses between the deep dermal-subdermal plexus and the more superficial plexus of the papillary dermis.
Free-form flaps can be classified into two main types: movable flaps and rotation flaps (which may include transposition flaps). Survival of free-form flaps is unpredictable. The paper refuted the early doctrine that a length to width ratio of 1:1 was required to guarantee the viability of the flap. Most flaps can be created with a length/width ratio of 3:1 or more if the facial flap has an axial-type blood supply directly through the skin vessels (eg, paramedial forehead flap).
Axial flaps
Axial or axially configured flaps (arterial flaps) receive blood supply directly from cutaneous arteries originating from segmental, axial arteries, or arterial anastomoses. Axial flaps may have a greater length/width ratio than free-form flaps. The distal, free part of the flap is an arbitrary flap by the nature of the blood supply. Based on this, the dynamic vascular area is larger than the anatomical area.
This supports the concept of an angiosome, which is a region of the skin that includes a flap fed by an axial vessel capable of expanding as the latter communicates with adjacent vessel branches. Arterial flaps feed on a specific vessel: deltopectoral - internal artery mammary gland, frontal - supratrochlear artery, ICHG flap - superficial temporal artery. The advantage of such a flap is that skin closure large area can be provided at the same time without including the bulky underlying muscle in the flap. The base of the flap should only be wide enough to accompany the vessel feeding the flap.
Loose patches
In the past decade, thanks to the development of microsurgical technologies, free tissue grafting on a microvascular anastomosis has become possible. These techniques allow the plastic surgeon to simultaneously move free axially configured flaps containing skin (fascio-cutaneous), skin and muscle (muscle-cutaneous) or skin, muscle and bone (musculoskeletal or bone-dermal) from the donor site to remote receiving bed. Under the microscope, it can be seen that the axial artery and vein feeding the flap anastomose with the recipient vessels located adjacent to the defect on the head and neck. Skin donor sites (fascio-skin flaps) are the forearm (radial forearm free flap), a free flap from the lateral surface of the arm, and a free flap from the lateral surface of the thigh.
The tissues of the periscapular, scapular, peroneal regions and the iliac wing zone are excellent donor objects when the defect captures the bone and surrounding soft tissues. If a large amount of tissue is required to reconstruct the defect, the rectus abdominis and latissimus dorsi muscles can serve as good donor sites. These flaps are usually harvested like muscle with skin overlying it. Although the free movement of tissues requires a trained surgical technique, special equipment and increases operating time, it provides the surgeon with an excellent alternative for the reconstruction of complex head and neck defects. In the rest of the chapter, attention is focused on the use of various flaps of arbitrary configuration for the reconstruction of facial defects.
Surgical planning and wound closure
Most of the facial defects encountered by plastic surgeons can be corrected by primary closure or local skin flaps. The choice of an appropriate method for closing facial defects requires an understanding of the biomechanics of wound closure.
Biomechanics of wound closure
Optimal wound closure requires an understanding of soft tissue mechanics and the principles of wound healing. The mechanical properties of the skin are primarily related to its collagen and elastin composition. Collagen types I and III provide the main supporting scaffold for the extracellular substance of the dermis. Elastic fibers in combination with collagen give elasticity or relative ease of deformation of the skin. When the skin is stretched, a period of slight deformation (segment I) is revealed on the “tension-tension” curve, which primarily depends on the thin elastin network. In section II of this curve, randomly arranged collagen fibers begin to elongate in the direction of the force, and the deformation becomes more difficult. Later, in section III, all collagen fibers are oriented in accordance with the direction of the force, and only a slight deformation is possible.
Clinically, when attempting to close a wound results in excessive tension (segment III of the stress-tension curve), the additional force does not result in tissue displacement, suggesting that other closure methods (grafts or flaps) should be resorted to. Excessive tension on skin flaps can lead to necrosis due to reduced blood flow, especially in flaps with marginal viability. In animal studies using 2 cm wide randomly shaped skin flaps, any flap over 6 cm long (length/width ratio over 3:1) was found to undergo necrosis regardless of tension. Any flap less than 2 cm long (length/width ratio less than 1:1) remained viable regardless of tension.
Intermediate length flaps were the most affected by tension. Flaps sutured at a tension of 250 g or less tended to engraft, while those sutured at higher tension necrosis. This study reinforces the clinical impression that tension on marginal viability flaps increases the incidence of necrosis. In another study, increasing tension was applied to randomly shaped skin flaps in piglets, and blood flow was measured in four areas of the flaps with a Doppler laser. As tension increased, blood flow decreased and stopped completely at about 250 g of force. To summarize: tension necessarily reduces blood flow in skin flaps; in flaps with excellent blood flow, tension may not be a critical factor, but in marginal viability it increases the incidence of necrosis.
Internal tension in the skin changes over time. Creep is the increase in stretch (change in length from its original length) noted when the skin is placed under a constant load. Tension relaxation refers to the reduction of tension in the flap when the skin is constantly stretched. Surgeons who use tissue expanders or progressive tissue excision techniques use these dynamic properties of the skin in their practice.
Attachments of the skin to the subcutaneous tissue are critical from the point of view of its mechanical properties, since a moderate separation of the skin reduces stress during wound closure and distributes skin deformations. The results of measurements of the mechanical properties of separated skin on an animal model were studied. A series of fusiform defects measuring 2 x 6 cm were created, and the edge was cut off with an indent of 2, 4 and 6 cm. The cut skin edge was pulled up to the opposite one, and a series of curves were built showing the force required to move the edge by a given distance.
In each case, separation of 2 and 4 cm caused the curve to shift to the right, thus indicating a decrease in tension in the flap at that shift. Wider separation, up to 6 cm, did not lead to any significant changes in forces and, in some cases, caused an increase in flap stress. In this model, moderate separation did not help to reduce flap tension, but could positively influence the restoration of cover continuity. The redistribution of tissue can be controlled to some extent by varying the length of the separation. Sometimes it is necessary to selectively cut edges, meaning to limit the separation around specific anatomical structures so as not to warp or deform them (eg, mouth commissure, eyelids, eyebrows, and nose tip).
Closure of spindle defects
Most small lesions on the face can be excised to create a fusiform defect, which, in turn, can be closed initially with a good cosmetic result. The key to optimizing this technique is to make cuts as parallel to the LRNA as possible. As a result, the maximum tension of the wound is parallel to the lines of maximum extensibility.
These lines are usually perpendicular to the lines of tension relaxation and represent the directions in which closure can be performed with minimal tension. If the surgeon wants to cut overall length spindle-shaped defect, M-plasty can be used. M-plasty is especially useful when a standard fusiform defect moves from one area of the face to another or crosses a natural facial sulcus (eg, buccal labial fold). Gilles fillet suture should be used to close the M-plasty angle. It shifts the ends of the M-plasty to the middle of the incision and prevents skin deformity at the ends of the incision (i.e. dog ear deformity).
Skin closure should be done in layers. An absorbable suture (Vicryl, PDS, Monocryl, or Machop) is placed on the subcutaneous tissue to invert and bring the skin edges closer together. One paper describes the placement of subcutaneous sutures further from the dermal margins of the incision to create significant eversion of the wound margins and reduce tension in the healing incision.
LOCAL SKIN FLAP
Most facial defects that cannot be sutured initially can usually be closed with local skin flaps. The blood supply to these randomly configured skin flaps is based on the subcutaneous vascular plexus. The flaps usually have a length/width ratio of 1:1 to 2:1. Some flaps on the face have an axial type of blood supply from direct skin vessels (for example, frontal). These flaps can survive at a higher length/width ratio due to the excellent blood supply.
All local flaps on the face for moving from the donor area to the defect have a rotary, stretchable section, or a combination of them. Most flaps, including those that are moved, have the function of rotation and stretching, the ratio between which is set when cutting out the flaps. When planning local skin flaps, the many needs of the defect must be identified and analyzed. The depth and configuration of the defect must be analyzed so that the reconstruction restores all its layers. When choosing the type of flap, regional differences in the thickness of the subcutaneous layer of the face should be taken into account. For example, a defect in the skin of the eyelid is much thinner than a defect in the skin of the tip of the nose.
Stretch flaps
The classically designed stretch flap has a length/width ratio of 1:1 to 2:1 and is designed to stretch across its entire width. These flaps are particularly suitable for closing forehead defects. On the forehead, bilateral stretch flaps are created with horizontal components running parallel to the LRNA and adjacent to the normal frontal creases. Sometimes excision of the Burrow triangles is required, but only after stretching the flap.
Rotary flaps
All pivot flaps also have a stretch component; therefore, many surgeons prefer to call them twist-and-stretch flaps. lines
rotations tend to follow the natural contours of the face, which is true, for example, for the flap in circular facelift and in lower blepharoplasty. The twist-and-stretch flap is usually designed to move in an arc of less than 30°. These flaps are easy to plan and usually provide minimal excess tissue and low suturing tension.
Although closure of a tissue defect may improve with more than 30° of flap rotation, tension will increase at the base and not along the length of the flap. The degree of stretching of the twist-and-stretch flap can be increased or decreased by modifying it. The classic twist flap is cut at a radius about two or three times the diameter of the defect and about four to five times the width of the defect in length, creating an approximately 90-degree arch. The flap in the form of a 90-degree arch is rotated 30° to close the defect. The arch of the flap can extend up to a maximum of 180°, although this is usually not required. Variations on the classic turn flap can be created by increasing the turn radius.
This changes the tension ratio and increases the width of the base and distal end of the flap. The base of the flap is not fixed, but stretches when the flap is moved into the defect. The degree of stretch can be increased by cutting back. It must be remembered that this will allow the flap to be advanced further and reduce tension on its distal portion, but it will narrow the base of the flap and potentially lead to malnutrition if overdrawn. Rotary-stretch flaps are used for large cheek defects. Such a flap should be chosen whenever there is a triangular defect. Two or three twist-and-stretch flaps can be used to close large circular defects. This is especially useful for closing scalp defects.
Moveable patches
The movable flaps can cut out and move into the defect with the primary closure of the donor site. These flaps can be planned in a variety of shapes and sizes, making the selection of the appropriate flap for a given defect somewhat confusing. There are three main movable flaps: rhomboid, bilobar, and Z-plasty.
Diamond flap
The 60-degree diamond flap is the classic diamond flap described by Limberg, which is a diamond with two 60° angles and two 120 angles. the maximum tension was along the lines of maximum skin tension, and the edges of the flap were in the lines of skin tension relaxation. The applied variant of the diamond configuration is a 30-degree flap that is moved into the diamond-shaped defect reduced by M-plasty.
Although somewhat more difficult to plan, the 30-degree movable flap helps reduce the angle of rotation, thereby distributing tension more evenly across the surface and minimizing dog-ear type deformities. The Duformental flap is another modification of the rhomboid flap that can be used for any rhomboid defect, not just 60- or 120-degree defects. It is suitable for 60-90° diamond-shaped defects where the surgeon chooses not to excise additional skin to create a sharper angle.
Most of the tension in rhomboid plasty is at the donor site to be closed. As far as possible, this line of tension when closing the donor site should be parallel to the lines of maximum skin tension. Double or triple diamonds are very convenient for closing large rectangular and circular defects. A standardized approach to cutting out diamond-shaped flaps allows you to choose the optimal flap for a given defect. First, the surgeon draws two lines parallel to the lines of maximum skin tension and creates two diamonds. Then, for each figure, four possible diamond-shaped patches are drawn.
Among these four flaps, one should be chosen from each pair, the short diagonal of which is parallel to the line of maximum skin tension. The rhomboid flap is particularly suitable for defects in the cheek and temporal region. Although this flap is tried and tested, versatile, and easy to plan, it requires customization of the facial defect. This can remove normal tissue and make the final scar more visible due to the precise geometry.
Bilobar flaps
The bilobar (bipartite) flap is another commonly used transposition flap that is created by mobilizing two common-base flaps to close the defect. The primary flap is the same size or slightly smaller than the defect, and the secondary flap is slightly smaller than the primary flap. Early descriptions of the bilobar flap indicate that each flap is rotated 90°, often resulting in large excess tissue and excess tension at the edges of the flap. Zitelli modified the bilobar flap so that each flap rotated approximately 45°. This technique reduces the amount of excess tissue and tension along the edges of the flap.
Sometimes the angles for these flaps are difficult to map and calculate when the flaps are placed over a convex or concave surface such as the bridge of the nose. The round template technique facilitates the creation of bilobar flaps with primary and secondary components of the appropriate size and with appropriate rotation angles. The bilobar flap is often used to cover small defects (1–2 cm) in the back and sides of the nose or cheek. The disadvantages of the bilobar flap are the length of the incisions, elastic fixation and skin deformation.
Z-plasty
Z-plasty is a double movement of two flaps of the same size. Z-plasty is often used to correct scars by lengthening a contracted scar or redirecting the scar to conform to skin tension lines or basic aesthetic units. The Z-plasty technique can be used to close defects located on one of its three borders. Usually, two flaps of unequal size and unequal angles are moved during defect closure. The concept is basically the same as lengthening in one direction and shortening in the other, with the orientation of the incisions changing. Finally, Z-plasty can help in closing wounds that cross junctions between major aesthetic units or to relieve unnecessary stress in important anatomical structures such as the eyelid, nose, and mouth.
Subcutaneous flaps on the leg
Stemmed subcutaneous flaps are used to move small amounts of tissue over a short distance. A triangular or serpentine patch of skin is cut out so that the blood supply comes from its subcutaneous pedicle. It is then mobilized and stretched to close the defect. Donor site closes on type V-Y plastics. Such a flap may also be designed to be rotated or moved onto a non-adjacent defect.
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