skin graft

A skin piece refers to a piece of skin that is simple or does not contain subcutaneous fat tissue. Skin grafting from one part of the body to another is called skin grafting. The site of the skin is called the donor site, and the site of the skin is called the skin zone. Treatment of diseases: burns, burns, chemical burns Indication Skin grafting is mainly used to repair superficial defects of soft tissue on the surface. Whether it is a fresh wound in the form of aseptic processing or a granulation wound with bacterial infection, skin grafting can be performed to prevent scar contracture or abnormal morphology that affects function. In addition, the skin piece can also be used to fill the cavity tube communicating with the body surface, such as the mucosal defect of the inner wall of the mouth, nose, vagina, or eye socket; the skin piece can also be made into a tube shape for repairing the blocked nasolacrimal duct, or prolonging the urethra Lower urethra and so on. Transplantation of allogeneic skin grafts can only survive in a short period of time, except for transplants between identical eggs. After transplantation, although blood circulation can be established between the early stage and the skin wound, it is similar to autologous skin grafting, but rejection occurs several days later. Allogeneic skin is mainly used in large-area deep burns, the autologous skin is insufficient, and the biological dressing temporarily seals the wound to save lives. The superficial skin is mainly used to close the wound. Such as third-degree burn wounds, you can use the surface skin to eliminate the wound; it can also be used to close the wounds with poor blood flow and bacterial infection. In addition, oral and nasal surgical wounds also need to be repaired with this type of skin. Full-thickness skin is usually used for areas such as face, neck, palm, and ankle that are worn and loaded. Medium-thickness skin is widely used in all kinds of fresh wounds and granulation wounds, and the thickness of the medium-thickness skin is determined according to the location of the affected area. Contraindications 1, with systemic diseases, can not tolerate surgery. 2, local infection, not suitable for surgery. Preoperative preparation 1. Improve the general condition, such as patients with anemia, low plasma protein, dehydration, etc., must be treated first. 2. The granulation wound needs to be prepared for a period of time, including unobstructed drainage, diligently changing the dressing and saline wet compress (usually wet for 2 to 3 days), proper pressure dressing, raising the affected limb, waiting for the germination color to be fresh and rosy, texture Solid edema, less secretion, no inflammation around the wound edge, can be skin grafting. If the granulation tissue is high, it is feasible to remove it. 3. Fresh wounds should be treated according to the debridement steps, so that the wounds have no active bleeding and necrotic tissue, and the edges are trimmed neatly. 4. The donor site should be shaved 1 day before surgery, brushed with soapy water, wiped dry, then rubbed with alcohol, wrapped with sterile towel, can not use strong disinfectant (such as iodine, etc.), so as not to damage the epidermis, reduce The skin is vital. Skin disinfection was performed with 1:1000 thiomersal and 75% alcohol during surgery. Surgical procedure 1. Position: The position of the patient depends on the location of the donor site and the affected area, so as to facilitate the aseptic operation. Usually the donor site is selected on the inner side of the thigh and the chest and abdominal wall, so it is generally taken in the supine position. When the lower limbs are supplied with skin, the lower limbs should be abducted and externally rotated, and the knee joints are flexed to facilitate the cutting of the skin. 2. Cut the skin (1) Cutting of the surface layer and medium-thickness skin Manipulation: Prepare a long, thin and sharp cutting knife to prepare (or use a straight tong to hold the razor blade), two pieces of wood, and immerse the cutting knife in 75% alcohol for 60 minutes (without boiling disinfection) To keep it sharp). The donor area should be flat and tense, and the muscles under the skin should be slack. For example, when taking the skin on the thigh or upper arm, the assistant uses one hand to pull the skin laterally on the opposite side of the donor site, and the other hand-held wooden board will longitudinally tighten the skin of the donor site; the surgeon pulls the skin in the opposite direction with a hand-held board Another hand-held knife, after the blade is diluted with a small amount of salt water, it is generally cut into the skin at a 15° angle to the leather surface, and is pulled forward by a saw-like reciprocating motion, and the wooden board is retracted with the cutting. The action should be uniform, smooth and rapid. The skin of the surface layer is grayish yellow, and the blade under the skin is faintly visible. The wound has a lot of bleeding points. The medium-thickness skin is gray and white. The blade below can not be seen through the skin. The wound has large and scattered bleeding spots. If there is fat, it indicates that it has become a full-thickness skin. Mechanical cutting: It is often unsatisfactory to cut large and medium-thickness skin pieces by hand. It needs to be cut with a drum-type peeling machine; it can also be cut by a roller-type peeling knife or an electric peeling machine. The drum picker consists of two parts: the frame and the body. The fuselage is divided into the main components such as the drumhead, the handle and the knife holder, and is contained in the sterilization box. Before use, check whether the machine is complete, whether the drum surface is clean, whether the blade is sharp, and whether the scale adjustment is sensitive after the blade is installed. Then, open the disinfection window, wrap it in a cloth, and autoclave. When in use, open the cloth and the sterilization box, and place the skinning machine together with the rack on the operating table. The blade is immersed and disinfected with disinfectant solution, and then rinsed with salt water, placed in a knife holder, aligned, and flattened to clamp the blade. The thickness of the skin can be adjusted by rotating the dial. Generally, the adult skin is about 0.2 to 0.25 mm, the thin medium-thickness skin is 0.3 to 0.45 mm, and the thick medium-thickness skin is 0.55 to 0.65 mm. Before taking the skin, fold the gauze 5-6 layers, cut into 2×2cm 2, and clamp it with a hemostatic forceps to make two gauze brushes. First take a piece of enamel glue and first apply the beginning and both sides of the drum, and then evenly brush the drum surface (first traverse and then apply horizontally twice). The donor site was also washed with diethyl ether and evenly coated with glue. The two-sided adhesive film for the skin can also be used to stick the film on the drum surface, and the skin area is not required to be glued again, which is easy to operate and has good effect. After the glue on the drumhead and the donor area is dry, hold the handle of the leather handle on the left hand, the thumb of the right hand, the handle and the middle finger hold the handle, place the open end of the drumhead on one end of the donor area, and press for half a minute for the drumhead and skin. Stick tight. Then, gently lift the skin picker with your left hand and push it forward to make the drum surface stick to the skin more firmly. Close the blade to the bonding point, and cut the skin piece by the right hand. After cutting to the predetermined length, turn the scale to the maximum, keep the blade away from the drum surface, pull the drum surface away from the skin, and cut the leather piece with scissors. If the required skin size exceeds a drum surface (10×20cm 2), after cutting a drum surface, it can be cut off, only the skin piece is removed from the drum surface, re-applied, and the thick skin piece is inserted into the knife holder. The gap between the drumheads continues to stick down to cut. In the same way, the leather sheet wider than the drumhead can also be cut to avoid stitching. (2) Cutting of full-thickness skin graft: When transplanting full-thickness skin graft, it is most successful if the original tension of the skin patch can be maintained. Therefore, before cutting, the shape of the skin wound should be cut with gauze or thin plastic film according to the size and shape of the wound area of the affected area, and then cut according to the sample. The depth of cut is not to enter the subcutaneous fat. The most ideal full-thickness skin graft can be seen on the wound surface with a fibrous tissue mesh that reveals fat in the mesh. A needle or a number of needles are pulled from one end, and after the edge of the incision is pulled, a sharp cut is made between the dermis layer and the fat, and the skin piece is removed. In order to facilitate separation and grasp the thickness, the indicator can be placed under the inverted skin piece, and the assistant presses the donor area to keep the skin tight and flat for operation. It is also possible to cut the skin and the subcutaneous tissue together, and then cut off the fat of the skin to form a full-thickness skin. The wound surface of the donor site can be directly sutured. 3. Skin graft fixation: The cut skin is implanted on the wound surface that has been prepared for preoperative fixation. The fixation method is divided into two types: suture fixation and non-suture fixation. (1) Stitching method: This method is suitable for skin grafting of sterile wounds. First cut the skin piece slightly to fit the shape of the wound in the affected area and stick it tightly. When suturing, the skin should have a certain tension, not too loose, nor too tight. The skin piece and the wound edge are sutured intermittently, and a long thread head is reserved every 1 to 3 needles, and the adjacent sutures are clamped by a hemostatic forceps to avoid entanglement and uneven tension when knotting. After suturing, pay attention to the effusion of the skin under the skin and rinse it with salt water, then spread the saline gauze containing antibiotics on the skin, evenly cover the loose gauze mass, so that the pressure is even, especially pay attention to the edge of the skin. Make the skin close to the wound. Tighten the gauze wraps (wrapped and wrapped) with the long wire heads that have been retained, and then wrap the dressing on the outside. In order to make the fixing firm, several strips of tape can be tightened. In the case of skin grafting where the wound surface is uneven or extremely difficult to maintain, in addition to fixing by the above method, intermittent suture through the skin piece and the wound base may be used, and the small gauze roll may be pressed and then ligated. When the granulation wound surface skin graft is not easy to fix, the needle can also be wrapped at the edge for wrapping. (2) Non-stitching fixation method: This method is often used for granulation wounds. Because suture fixation is not conducive to drainage, the wound edge is weak and not resistant to suture traction. Generally, the skin piece is cut into a stamp or a large piece of leather, which is directly attached to the wound surface, and a certain distance is maintained between the skin pieces to facilitate drainage of secretions. The granulation tissue does not need to be cut off, and the skin should be stretched flat and close to the wound. The part with small wound or easy to be wrapped is covered with a thin layer of saline gauze larger than the wound surface after skin grafting. It is evenly flattened with a number of loose dry gauze, and then covered with dry gauze and cotton pad. Large areas of skin grafting or difficult to dress (such as the face, buttocks, perineum, etc.), feasible exposure method, do not cover any dressing, always carefully remove the wound secretion. In addition, it is important to have sufficient patient cooperation to maintain a constant room temperature and good ventilation. When skin grafting in the cavity tube (such as the eye socket, mouth, vagina, etc.) that communicates with the body surface, due to the limitation of the visual field, it can not be sutured and fixed, only a few sutures can be used, and then blocked with gauze, rubber tube or dental impression molding gel. Support is fixed.