With the development of industrialization in society, the number of patients with electrocution injuries has been increasing year by year. Electrocution injuries are unique, with inlet and outlet, accompanied by vascular injury and secondary thrombosis, etc., which easily cause deepening of the wound and exposure of deep tissues, thus resulting in a high amputation rate and mortality. Since 2009, we have tried to use the anterolateral femoral flap free grafting to close the deep trauma of electric shock injury at an early stage, and achieved good clinical results, which are reported as follows. 1, Objects and methods 1.1, Clinical data There were 12 patients in this group, including 10 males and 2 females, aged 32 to 60 years old. Injury-causing current included 1000 to 10000V ranging. The deep trauma sites included: head, wrist, dorsum of foot, knee joint, etc., all of which were III-IV degree trauma. The defect area ranged from 225px×400px to 625px×250px. All patients were admitted to our department directly after injury. 1.2, Surgical treatment Surgery was performed in two stages, including one-stage debridement and two-stage free flap repair. After the patients were admitted to the hospital and treated with routine treatments such as anti-shock and rehydration, they underwent emergency debridement within 24-48 hours, and after 3-5 days after the operation, according to the trauma, the shallow trauma was treated with thin-medium-thickness skin grafting, and the deep trauma with exposed tissues such as bone or tendon was treated with free anterolateral femoral flap repair. 1.2.1, debridement: use 3.O% hydrogen peroxide, 1g/L chlorhexidine, saline solution to repeatedly rinse and soak the wound, disinfect and spread the towel. In accordance with the order from the outside to the inside, from the surface to the inside, remove the necrotic tissue. Since the tissue damage of electric shock injury is characterized by small mouth and big bottom, and sandwich necrosis, i.e., the necrosis scope is often deep and extensive, and the necrotic tissues and normal tissues often exist alternately, it is necessary to expand the trauma thoroughly, and probe into the deep tissues. Carefully remove the necrotic tissue and try to preserve the interstitial tissue. Nerve and tendon tissue with good continuity must be preserved. Intraoperative attention is paid to exploring the major blood vessels to understand their patency and the extent of damage, laying the foundation for second-stage free flap repair. After clearing the wound, the trauma is covered with allograft skin punching holes and VSD continuous negative pressure suction. 1.2.2, anterolateral femoral free flap repair: At the second-stage surgery, first assess the trauma and the vascular condition of the recipient area. The delayed necrotic tissue was further removed, on the basis of which the vessels in the affected area were explored and dissected proximally to the normal segment. Tissue flap fabric samples were cut according to the size and shape of the traumatic defect and the location of vascular anastomosis was marked. Taking the midpoint of the line between the outer edge of the anterior superior iliac crest and the outer superior angle of the patella as the axis, the line was used as the axis, and the flap was designed and enlarged appropriately compared with the fabric sample. The skin was first incised along the medial edge of the flap and lifted medially at the deep side of the broad fascia, usually two to four dermal branches penetrated through the vastus lateralis muscle or the muscle gap, the thickest dermal branch was selected for freeing, and the descending branch of the rotator cuff artery was separated upward to look for the descending branch of the rotator cuff artery, and the long vascular tip was retained as much as possible to ensure that the anastomosis was located in the healthy tissues. Depending on the size of the traumatic tissue defect and the base of the wound, the flap may be stripped with a portion of the lateral femoral muscle to fill the dead space. If the tissue defect is small, the flap will not carry the muscle, but only one or two percutaneous branches, forming a percutaneous flap. The veins of the tissue flap are anastomosed end to end with the veins of the recipient area, and the arteries are anastomosed end to end as much as possible to ensure distal blood flow. The ratio of arteries to veins is 1:2, and for those with severe vascular injury and large defects, the saphenous vein of the lower limb can be taken for bridging anastomosis. Use the skin flap to cover the traumatic bone, tendon, joint capsule and other structures. If the trauma is too large to be completely covered, then supplementary skin grafting should be performed. The donor area was repaired by direct suture or medium-thickness skin graft. Postoperatively, the affected limbs were routinely immobilized in plaster, and anticoagulant drugs such as low molecular dextrose and popovine were applied. 2, results 2.1 this group of patients after surgery, all the flap survival, no vascular crisis occurred. 2 cases of subcutaneous flap infection, after again cleaning, continuous antimicrobial solution rinsing after healing. The remaining patients were discharged from the hospital with one stage of wound healing. At 3 to 24 months of follow-up, the color and texture of the flaps were good. 2 patients underwent flap debridement because of bulky appearance, and the rest of the patients had an acceptable appearance. Except for one patient with severe limb injury, the rest of the patients achieved the expected results in terms of appearance and functional recovery of the donor and recipient areas. 2.2 Typical case Male, 43 years old, laborer, was injured by 10,000-volt high-voltage electric shock during operation, with the right upper limb as the entrance and the right foot as the exit. 24 hours after the injury, trauma debridement was performed, and the right upper limb was found to be completely necrotic, and amputation was performed. After debridement of the right foot, tendon and bone were found to be exposed. After 5 days of negative pressure suction by VSD, the right anterolateral femoral perforator flap was used, with a size of about 25×300px, and the recipient vessel was the anterior tibial artery, which was anastomosed end to end and end to end, respectively. The flap was completely viable after surgery. The following figure is shown: 3. Discussion Electrocution injury is the generation of heat when the electric current is conducted in the body, which causes necrosis of deep tissues such as muscles, nerves, blood vessels, etc., and sometimes it can cause damage to the heart, kidneys, nervous system, etc. The wound is usually composed of inlet and outlet, and the wound is usually caused by the blood vessels. The trauma generally includes an entrance and an exit, and is of the form of a small mouth and a large bottom, with a carbonized surface. It is often characterized by deep and extensive burns. Due to the inconsistency of the tissue structure and electrical conductivity of each part of the thermal damage tolerance, as well as the differences in the distribution of the electric field in various parts of the body during electrocution and resistance caused by the degree of burns are not the same. Caused by the current through the burn site was “segmental” and muscle “stuffing-like” necrosis, “sleeve-like” necrosis around the bone and other complex and diversified manifestations of the current caused by the local blood vessel The local vascular injury caused by electric current will further cause ischemic necrosis of the blood supplying tissues, and after the soft tissue necrosis is detached, the wound surface will deepen, leading to the exposure of deep tissues, which will increase the difficulty for treatment. The debridement is a key step in the treatment of electrocution injury, and the reasonable timing of debridement and the judgment of the scope of debridement are of great significance to the prognosis. Because of the characteristics of progressive necrosis, it is difficult to determine the scope of necrosis in the early stage of electrocution, therefore, it is often chosen to perform debridement 6 to 12 days after injury. However, due to the late time, local tissue infection and corruption, wound deepening and systemic complications often occur. In our cases, we chose to perform early debridement when the patient’s vital signs were stable, usually 24 to 48 hours after injury. On the basis of removing obvious necrotic tissues, the first traumatization was performed to preserve the viable tendons, blood vessels, nerves and other inter-ecological tissues as much as possible, so as to create conditions for preserving the local functions. Due to the early expansion of the wound, it is sometimes difficult to fully determine the extent of necrosis during the operation. Therefore, after the first debridement, the wound was first covered with allograft skin plus VSD drainage. As a good biological dressing, the allograft skin can effectively protect the tissue, create a good environment for its recovery, and reduce tissue necrosis caused by improper covering materials. VSD negative pressure drainage can improve local blood circulation through negative pressure, effectively adsorb and remove liquefied necrotic tissue, and play a certain role in debridement. In this group of cases, routine debridement was required before free flap coverage. Since the necrotic boundaries were basically clear about 3 to 5 days after the first surgery, it could further make up for the insufficiency of the first debridement and avoid the loss of normal tissues caused by excessive debridement. The anterolateral femoral flap was first proposed by Xu Dachuan et al. in 1983, and Luo Lixian was the first to report the clinical application of the flap to repair tissue defects with success in 1984. The advantages of this flap are longer vascular tips, thicker caliber of blood vessels, carrying the anterolateral femoral cutaneous nerve, large cutting area, no sacrifice of major blood vessels of the limb, and convenient intraoperative position. Because of the wide range of indications, it is also known as the “universal flap”. Due to the combination of extensive skin and soft tissue injury, it is often impossible to use local flap repair, in skilled microvascular anastomosis technology, free flap is a more flexible choice, the repair area and range is more extensive. Early free flap repair helps the recovery of meso-ecological tissues, prevents secondary infections, and maximizes the recovery of limb function. The important factor for the success of free flap is the selection of the anastomosis point of blood vessels in the affected area. Due to the heavy local vascular injury of electric shock injury, it is often necessary to carry out high anastomosis, so the flap is required to have a long vascular tip. The long vascular tip of the flap is also conducive to placing the anastomosis on a well-textured tissue bed, avoiding inflammatory tissue irritation at the injury and thus reducing the occurrence of vascular crisis. Because of the high damage to the vessel by the current and the increased probability of thrombosis, the vessels in the recipient area need to be carefully separated proximally when selecting the vessel, while the intima is carefully observed under the microscope. Those with damaged intima or separated from the mesentery should be further separated upward, and if the vascular defect is large, autologous saphenous vein grafts and other methods can be used. In conclusion, early debridement and multiple debridements should be sought after electrocution, and free anterolateral femoral flap grafting is an effective method to close deep wounds.