The causes of surgical scars should be understood as the healing process of post-surgical trauma, in the order of hematoma —- granuloma formation —- tissue remodeling and scar formation. Granulomas are very fragile, bleed easily and cannot resist traction. Only when the fibroblasts in the granuloma multiply and a large number of collagen fibers are secreted can the surgical wound heal completely! Postoperative scarring in general is difficult to avoid, only by minimizing the extent of scarring and paying attention to the concealment of the incision. Prevention and treatment mainly starts from intervening the factors affecting scar formation. The factors affecting scar formation are as follows: A. Skin tension (including external tension caused by the degree of skin tissue deficiency and the inherent tension of the skin tissue itself. The areas with high tension and much activity are prone to hyperplastic scarring, such as the chin, anterior sternum, deltoid, upper back, elbow, hip, knee, ankle, dorsum of foot, etc.). B. Age (young people are prone to hyperplastic scarring, especially the highest rate of hyperplastic scarring occurs at the age of 10-20 years old, mainly due to the vigorous tissue growth during youth development, strong post-traumatic reactivity, and high skin tension). C. Skin pigmentation (people of color have more pigment cells and are also susceptible to stress reactions; the incidence of keloid scars in blacks is 9 times higher than that in whites; they are likely to occur during periods of pituitary physiological activity such as puberty and pregnancy). D, infection (repeated infection, long-term trauma exposure, excessive proliferation of granulation tissue, prone to hyperplastic keloid or keloid scar). E. Foreign bodies falling into the trauma (dust, talcum powder, fibers, as well as hair follicles, sebaceous glands, and sweat gland residues can cause tissue reaction and lead to keloidal hyperplasia). F, other factors (the angle between the incision and the skin, a cut perpendicular to the skin has the thinnest scar after healing; the larger the angle of inclination, the wider the scar in the dermis and the more obvious the skin deformity. There is also the depth of the trauma and the healing time of the trauma). The scar is most reactive at 2-3 months after the injury, and most of the scar tends to stabilize and soften 6-12 months after formation, and some of them can be up to 5-6 years. Therefore, the revision time is appropriate more than six months after the injury (except for those with functional effects), with full consideration of the nature, size, formation time, location, and angle to the skin line of the scar. For superficial scars, skin abrasion is feasible; for extensive deep scars, skin expansion or skin grafting can be considered; for scars at an angle to the skin line, “Z-plasty” or direct “W excision” can be considered. For angular skin lines, “Z-plasty” or direct “W excision” can be considered. For skin excision suture, small needle and fine thread must be used, and the dermal suture is more effective; the removal time is usually 5 days.