In our daily life, it is always inevitable to be subjected to a variety of accidental trauma, skin trauma, cuts, burns, skin infections, surgery and so on, the human body in the event of trauma, the body will start the repair process, the formation of trauma to repair and restore. There are two types of repair processes: complete regeneration (complete restoration of the structure and function of the original tissue) and incomplete regeneration (also known as scar repair, through the proliferation of granulation tissue, to fill the tissue defects, and gradually transformed into scar tissue). Obviously, complete regeneration leaves no traces of trauma, whereas scar repair, on the other hand, leaves its mark on us, and this is exactly what we are going to talk about today. For trauma to the skin, there is a division into one phase of healing and two phases of healing. Phase I healing exists when the trauma is minor, the margins of the wound are neat, the defect is small, there is no infection, and the alignment is tight; otherwise, phase II healing is formed. The scarring in stage 1 healing is mild and is usually not a concern unless there are special areas. Stage II healing will result in significant scarring, which is a variety of scarring that affects appearance and function. Scarring can cause undeniable psychological and physical damage to the patient. Smaller scars may only have an aesthetic impact, while more extensive scars may not only have an aesthetic impact, but may also have a severe functional impact, preventing physical mobility and stretching, and a large percentage of patients with scarring suffer from chronic neuropathic pain. Depending on the degree of trauma and the extent of involvement, different forms of keloid scars may be formed: (1) Depressed keloid scar and atrophic keloid scar, where the skin at the scar forms adhesions with the subcutaneous tissues to form a slightly flat or depressed deformity on the surface of the body. (2) Hyperplastic keloid scar The injury involves the deep dermis, and the scar is significantly higher than the surrounding normal skin, with localized thickening and hardening. In view of the differences in the treatment of these two types of scars, as well as the limitation of space, in this issue, we focus on the treatment strategies of depressed scar and atrophic scar. Treatment strategies for hyperplastic scarring will be described later. For the treatment of depressed scar and atrophic scar, we need to address two aspects: (1) The skin quality of the localized skin at the scar, including the color, hardness and elasticity of the skin. (2) Inadequate soft tissue of the subcutaneous tissue at the scar site. At present, for the repair of depressed scar and atrophic scar, surgery can be taken to excise the local scar skin, as well as loosening the subcutaneous tissue adhesions, with the surrounding tissue transfer for volume filling. For small depressions and scars that are not too extensive, better repair results can be achieved. However, for larger extent and depth of depressed scarring, it is difficult to solve the challenge of insufficient subcutaneous tissue volume. Autologous fat particles are an excellent source of autologous tissue, and as the use of fat grafting is becoming more widespread, its application to the treatment of depressed and atrophic scarring is also a natural fit. The application of autologous fat grafting to depressed scar and atrophic scar has been used for many years both at home and abroad. Let’s take a look at the results: After the patients were treated with autologous fat grafting for depressed scar, not only did they get an increase in volume, the skin regained its near-normal contour, but they also got an improvement in the quality of the skin at the scar site, and the skin color, hardness, evenness, and elasticity at the scar site all improved dramatically. Improvement. The patient achieved aesthetic and functional results with high patient satisfaction. This treatment not only provides volume filling and changes in scar color, hardness, etc., the biology of the fat particles is an important mechanism of action. The fat stem cells in the fat particles can continuously secrete a large number of growth factors to stimulate the synthesis of collagen fibers in the scarred area, which leads to some repair of the dermis and subcutaneous tissues, and ultimately improves the skin quality. In addition, localized immunoinflammation after fat grafting may have a remodeling effect on the scar tissue through fat precursor cells and macrophages, removing unhealthy cells and ultimately replacing them with normal cells, producing permanent tissue repair. In histologic terms, autologous adipose tissue grafting regenerates a dermal and subcutaneous tissue layer that reconstitutes the normal skin structure through increased fat layer thickness, collagen deposition, and localized vascular regeneration. It is important to realize that the lack of subcutaneous tissue and the lack of regeneration after various traumas are important factors in scarring. Neuropathic pain due to scarring is a difficult problem for burn patients, and in a large percentage of burn patients this pain is chronic and life-altering. Recent studies have shown that autologous fat grafting can relieve neuropathic pain in the scarred area while repairing the scar. Mechanisms of action may include: fat grafting may be able to modulate microglia activation and inhibit neuropathic pain production; adipocytes and adipose stem cells can produce various mediators that inhibit inflammation, such as the cytokine IL-10, and studies have shown that IL10 treatment can alleviate neuropathic pain. In conclusion, autologous fat, as a good soft tissue filler, is used in the treatment of depressed and atrophic facial scars, not only reshaping the contour deformity caused by scarring, but also improving the local skin texture and skin color to a certain extent, without producing new deformities and new scarring, achieving good clinical results, and having obvious application advantages in the present day, when minimally invasive treatments are highly respected, and is worth popularizing and applying. With the deepening of the research, the application of autologous fat grafting will play an important role in the future treatment of scar, not only that, with the advancement of the application of adipose stem cells in the clinic, the application of adipose stem cells in the treatment of scar will also be an important direction in the future.