The damage to the human body from electric shock is mainly direct damage to human cells8 and thermal damage to human tissues and organs from heat generation by the electric resistance of body9. The skin and subcutaneous tissues suffer various degrees of burns, deep tissue (muscles, fat, tendons, etc.) become edematous, and the compression of the nutrient vessels leads to occlusion and ischemic necrosis of the tissues. In addition to scalp necrosis, electrical burns to the head are often accompanied by periosteal and cranial involvement, while brain parenchymal injury is rare, but care should be taken in the diagnosis to exclude10. Since the 1980s, there have been many reports on the application of local scalp flap transfer11, pedicled oblique muscle flap, free greater omentum with skin-grafting12 and free flap13 graft to repair electrical burn wounds with skull necrosis in the head after emergency debridement. In the repair of electrical burns on the head with cranial osteonecrosis, the method of removing all of the necrotic cranial bone or drilling the cranial bone to allow the granulation tissue to grow and then transplanting the skin piece is now less commonly used. And the osteonecrosis in electrical burns can be judged by the color of the bone. Electric shock injury to the head should be concerned not only with the repairment of defect and appearance, but also with restoring the function of the head. For small electrical head burn wounds with skull necrosis or exposure, many reconstructive microsurgeons use early expansion of the scalp flap to cover the defects while avoiding skin-grafting and hair loss14. The ideal repair of electrical burns to the head should include scalp and skull repair as well as hair reconstruction to achieve unity of appearance and function. In this case, free flap is considered a better approach to repair the defect. The representative free flaps are: latissimus dorsi muscle flap, ALTP, rectus abdominis muscle flap, and inferior oblique muscle flap. The constant vascularity, large excisional area, rich blood supply, and ability to resist infection are the advantages of latissimus dorsi muscle flap, but its bulky appearance and the need for postoperative braking increase the difficulty of care. The use of dermal scaffold + skin-grafting technique15 for repairing skull exposure in head defects has also been reported to reduce surgical trauma and is suitable for elderly patients with poor body constitution. However, because the dermis cannot grow hair, hair transplantation is required later for patients with special needs, and due to the technique is expensive, the application of it was limited. Based on safety, economic and postoperative efficacy considerations, the ALTP was preferred to repair the large defects of head after electroshock injury in our study.
Since the report of ALTP by Koshima et al.16 in 1993, it has been widely used in the repair of various parts of the body, and is therefore also known as a "universal flap". And based on the evidence mentioned above, we used the free ALTP to perform the reconstruction of the head defect after electric shock injury. Through the application of this technique in 25 patients, it provides some advantages as mentioned here:1) The descending branch of the lateral femoral circumflex artery is one of the most important branches of the lateral femoral circumflex artery, and it has high reliability of blood supply, stability of position and low anatomical variability as the origin trunk of the flap17. 2) The diameter of the descending branch of the lateral femoral circumflex artery (1.7–2.6 mm) and the diameter of the superficial temporal artery (2.0-3.3 mm), the diameter of the occipital artery (1.4–2.5 mm) and the diameter of the posterior auricular artery (1.2–3.4 mm) basically coincide in size. Therefore, the flap vascular can be well matched to the recipient site and anastomosed easily. 3) The ALTP, which contains broad fascia, has good elasticity and abrasion resistance, and also increases the protection of brain tissue.4) The anterolateral femoral cutaneous nerve can be included and anastomosed with the trabecular cutaneous nerve to make the flap with sensory function. 5) Faced with a large area of soft tissue defect trauma in the head, the expansion flap faces a limited amount of tissue in the donor area. The ALTP can be excised over a large area. The flap can be removed over the 2/3 of the thigh, which is suitable for repairing large soft-tissue defects.6) For electric shock defects, the flap is highly resistant to infection and reduces the risk of long-term non-healing of infected wounds. And we did observe some drawbacks in the use of this method:1) Since there is no hair in the flap area, patients with special requirements for hair are recommended to have a second stage hair transplant to make it more satisfactory. 2) In obese patients, the flap is bulky and often requires surgical thinning.3) Due to the abundant blood supply in the recipient site, it is necessary to anastomose the veins as much as possible to enhance venous drainage.
Several tips can be shared about this study. Firstly, based on the opinion of Khalid et al18,radical and thorough debridement is a key factor influencing flap survival after surgery. Intraoperative attention should be paid to thoroughly remove necrotic tissue from the electroshock wound and remove necrotic cranial bone tissue to prevent contamination and further injury. Secondly, the patient was positioned appropriately after surgery depending on the position of the flap to avoid pressure on the flap vascular pedicle. Next, for occipital flap repair, the postoperative position is prone or lateral, and for the parietal or temporal region, the position is flat or 45° oblique lateral. Last, the flap should be designed as close to the root of the thigh as possible, because if the defect is wide, the donor site may not be closed in one stage, and the pedicled abdominal flap can be chosen to repair the donor site.