Flap transplantation

Skin flap transplantation is to transplant the skin and subcutaneous fat from one place to another. The transplanted tissue is still partially connected to the donor area. This connected part is called pedicle, so it is also known as pedicle skin grafting. The part that is transplanted is called a flap, so it is called a flap graft. The blood supply of the flap is temporarily supplied by the pedicle. After transplantation, the flap establishes a new blood supply relationship with the skin grafting area. After the flap can obtain sufficient blood supply from the skin grafting area, the pedicle can be cut off. Treating diseases: hand trauma Indication First, repair the defects of the full layer of skin. Second, covering the bones, tendons and the exposed parts of the main nerves and blood vessels. Third, repair the pressure surface of the foot, fingertips and other pressure. Fourth, the reconstruction of organs, such as the nose, ears, fingers and so on. 5. Supply nutrients, such as repairing radiation ulcers, hemorrhoids, and anterior tibial or scalp skull injuries including bone defects. General principles and points of attention in flap formation and metastasis. 1, in order to ensure that the flap has sufficient blood supply, the ratio of pedicle width to length of the flap should generally not exceed 1:1.5, ideally should be 1:1 head, neck flap width and length ratio can be increased, the lower limbs The length of the flap should be reduced.) 2, the flap is best designed according to the direction of the blood vessel, the pedicle should fall on the centripetal end, and the pedicle will not be over-twisted during the transfer process, so as not to affect the blood supply. 3. Try to avoid damage. The flap is a transient ischemic tissue that is less viable and cannot tolerate damage from rough manipulation. Therefore, the operation requirements are very detailed and care for the organization. Instruments are also required to be sharp and delicate. 4. When the flap is formed, its thickness should include subcutaneous fat tissue. If you need to repair fat during the transfer, you should pay attention to preserve the integrity of the subdermal vascular network. 5, perfect hemostasis, to avoid hematoma under the flap. There must be good braking after surgery to ensure that the transferred flap is not pulled, and the flap will not be necrotic or avulsed. 6. After the flap is formed, if the skin color is rosy, the wound edge continues to ooze blood, and the blood color is bright red, indicating that the vitality is unquestionable and can be transferred to the skin grafting area. When suturing and dressing with dressing, the flap needs to have proper pressure to facilitate venous return, but the pedicle can not be subjected to any pressure to avoid obstructing blood supply. 7. If the ratio of pedicle width to length of the flap has exceeded the limit; or the flap cannot be designed according to the direction of the blood vessel, it is estimated that when the blood flow may be insufficient in the metastasis to affect the flap viability, "delay surgery" may be considered before the transfer. In addition, after the formation of the flap, if the flap is found to be pale or bun on the far side, although it is treated properly, there is still a blood flow disorder. If it is estimated that the vitality cannot be ensured after the transfer, it may be considered to be sutured back for delayed transfer. The method of delaying the flap is to cut the edge of the flap, completely or partially peel off along the shallow layer of the deep fascia, cut off the blood supply of the homemade margin and the base, and then sew back. After 2-3 weeks, transfer again. The purpose of "delayed surgery" is to increase the diameter of the vessel during the "delay" process; the alignment of the vessels gradually coincides with the long axis of the flap; the number of vessels is also gradually increasing. Through the above changes, the blood supply of the flap is sufficient, thereby ensuring the safe transfer of the flap. It is composed of a pair of triangular flaps with opposite positions. After the position is changed, the tension is relaxed, the length is increased, and the local shape or function is improved. The operation is simple and the effect is large, so the application range is wide. When the linear scar contraction is relieved, the skin on both sides of the scar is required to be complete and has a certain degree of looseness before the method can be used. For the contraction of flaky scars, this method is not suitable for recovery. Surgical procedure Judgment of defect First, find out the injury at the defect, including the location, shape, size, the presence or absence of severe contracture, surrounding skin conditions, and the conditions of the wound, etc., and select the appropriate flap area for the above conditions, such as the anterior and posterior parts of the neck. If there is contracture, the defect area after the scar is released may increase in number and must be fully estimated. At this time, the size of the same part of the healthy side or healthy person can be used for prediction. To reduce design errors. Supply area and flap type selection The principles of selection are roughly as follows: 1. Select the skin texture and the approximate color of the area for the flap area; 2, with local, adjacent flaps, safe and simple solution is preferred; 3. Avoid unnecessary "delay" and indirect transfer as much as possible; 4, the design area of the flap should be about 20% larger than the actual wound after the resection of the scar; 5, should be as much as possible to choose a blood-rich shaft-shaped flap or island flap transplantation. Retrograde design Retrograde design or cutting the specimen is an essential step in the design of the flap. The general procedure is as follows: 1. Firstly, the size, shape and length of the flap required for the defect area are drawn in the flap area; 2. Cut the simulated flap with paper (or cloth) according to the above pattern; 3. Fix the pedicle to the donor flap area, pick up the paper type (or cloth type), and try to transfer it once. Depending on whether the patient can be more relaxed or not, it will be covered according to the actual situation of the patient. The position design of the simulated test is called the retrograde design, also called the flap reversal design method. It is an effective measure to prevent the design from deviating from the actual situation. It should not be ignored and omitted when discussing before surgery, because only through this A retrograde design can test the flaps we designed. The specific size, position and shape of the flaps can be consistent with the defect area, and the patient can tolerate this position. The formation of the flap: When the flap is formed, attention should be paid to the blood circulation of the flap. The early nutrient supply after the flap is formed depends mainly on the blood circulation of the pedicle to maintain its vitality. The ratio of length to width of any flap should not exceed 2:1. The blood circulation is good in the face and neck. The ratio of length to width can be slightly increased to 2.5~3:1. Blood flow can occur at the distal end of the flap. Obstruction or necrosis, when designing the flap, the pedicle should be slightly wider, and the direction of the main blood vessels should be circulated to ensure blood circulation. In recent years, the study of the vascular structure of the skin has been gradually deepened, and the skin artery has been drawn into a pattern to grasp the level of reference when forming the flap. The supply of arteries of the flap is important, but the venous return can not be ignored. If the venous return is not good, the flap will swell or blisters and become dark purple. Finally, due to severe tissue swelling, the artery is compressed and the blood flow is completely blocked. Skin flap necrosis. The main blood vessels that nourish the flap are in the deep tissue of the flap, and the large flap must include deep fascia to protect the vascular network deep in the subcutaneous fat. If the flap is too thick to affect the local function or appearance after repair, the fat can be removed (ie, delipidated) after the flap is transferred for 3 to 6 months. complication First, the blood barrier The blood supply disorder is the most common complication after flap transplantation. In severe cases, large tissue necrosis may occur or the surgery may fail completely. 1, clinical manifestations: First, the arterial blood supply is insufficient, the surface of the skin is pale, the local temperature drops, this situation is relatively rare, often caused by temporary reactive vasospasm, if found during surgery, given hot compress or small dose of vasodilation Most of the agents can be recovered. If it occurs after the operation to add blood volume, heat preservation, pain relief, expansion and anticoagulation measures to clear the microcirculation. The second is venous return disorder, which is characterized by swollen flaps of the skin flaps. The light skin color is pale red purple spots. In severe cases, small blisters or purple-black spots may appear, which occur mostly at the distal end of the flap. This condition usually occurs within 2 to 3 days after surgery, gradually increases and the range expands. After 5 days, it tends to be stable. The lighter gradually improves after 5 days, and the epidermis falls off, which has no major effect on the treatment. Part or most of the necrosis. 2, the reason: the flap design is not appropriate, the ratio of length to width is too large or there are more scars in the donor area, the condition of blood supply in the transplanted flap is insufficient; the operation is rude, the main blood vessel or the suture tension is too large, the flap is twisted, Extrusion, etc., causing blood flow reflux disorder; imperfect hemostasis, resulting in hematoma under the flap, resulting in increased local tension, and affecting blood supply; due to less sterile operation, local infection can also cause or aggravate flap blood supply Obstruction; improper dressing or postoperative fixation is inadequate, the pedicle of the flap is pulled and compressed, resulting in insufficient blood supply or backflow. 3. Nursing: When there is a blood vessel disorder in the flap, the first reason should be to check what causes it. If there is a blood circulation disorder after operation, the arterial fistula can pass the heat preservation, sedation, pain relief, blood volume supplementation, application expansion and dredge microcirculation, Dilation of vascular drugs, hyperbaric oxygen therapy is feasible when conditions permit. Venous reflux disorder is applied to the dressing pressure dressing, raise the limb or the distal end of the flap, take the position drainage, gently massage the distal end of the flap to the pedicle with the finger, etc., and also remove some sutures, apply heparin, lidoca The wound edge is soaked by a physiological saline solution. Or cut the venules on the edge of the ligated incision to make the blood flow out, and re-establish the circulation within 3 to 5 days. The venous return is improved and the flap may survive. Second, hematoma When there is obvious hematoma under the flap, report it to the doctor immediately, remove some of the suture, clean it up, and wash it with saline if necessary. If there is a bleeding point, try to ligature, then place a rubber sheet, a half hose or a negative pressure drainage. . Third, the flap avulsion Proper fixation and braking during flap transfer are necessary measures to prevent avulsion from limb movements. Therefore, preoperative safety education for patients is very important, and full cooperation of patients is required. Fourth, infection In general, flaps rarely occur in the process of metastasis. Mild infections occur after flap pedicle surgery, especially when there is a wound under the pedicle. The local blood supply condition is poor after the pedicle surgery. It is more prone to infection and less prone to healing. In the case of severe trauma, on the one hand, it may be due to serious pollution. On the other hand, in the early debridement, it is inevitable to distinguish the inactivated tissue and make the necrotic tissue residue more liable to liquefy infection, resulting in surgical failure. Should pay attention to anti-infective treatment, enhance systemic resistance, thorough debridement during surgery, topical antibiotics, placement of negative pressure drainage, postoperative signs of infection, early removal of sutures, adequate drainage, to prevent infection spread.

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