Burns, burns, crushing injuries, lacerations, etc. leave deep scarring on the face of many injured people. As they grow older, many childhood scars on the face and limbs become a lingering pain in their hearts, and schooling opportunities are invariably limited. In recent years, more and more patients are asking for scar repair. Here I would like to introduce the principles and methods of scar repair in detail. Scar (scar) tissue is the fibrous connective tissue formed by the maturation of granulation tissue through alteration. At this point the tissue consists of a large number of parallel or interlaced bundles of fibrous connective tissue. The fibrous bundles are often homogeneous and red-stained, i.e. glassy. Fibroblasts are sparse, with elongated, darkly stained nuclei and reduced vascularity within the tissue. The tissue is largely locally contracted, pale or grayish translucent, and hard and inelastic. The role of scar tissue is twofold: firstly, scar is beneficial to the body: ① it fills the damage gap and keeps the tissues and organs intact; ② it is not as strong as the skin in terms of tensile strength, but it is stronger than the granulation tissue in terms of tensile strength and can keep the damaged area strong. The unfavorable side of the muscle: ① scar contraction, which often restricts movement; ② scar adhesions, especially fibrous adhesions between organs or between organs and body cavity wall, can affect its function, and extensive damage in the organ leads to extensive glassy changes, and organ sclerosis can occur. (3) Excessive proliferation of scar tissue, also known as hypertrophic scarring, also called keloid scarring. The most important thing for scar repair is a detailed analysis and proper diagnosis of the problem before the goal can be determined. Rather than simply removing the scar and then closing it better, it is important to define what the scar will look like after repair. With all kinds of keloid scars, the difference depends on four factors: 1. Flatness: flat keloid scars are easy to cover up with makeup and raised or depressed keloid scars are difficult to conceal. 2. Width (area): usually keloid scars are brighter in color than the surrounding skin, and this difference is easily concealed on narrower keloid scars. Large scar repair after burns is impractical and is usually corrected with collagen stimulation methods such as grinding or laser. 3. Direction: A scar located at the border of the facial cosmetic unit or in the direction of the dermatoglyph is not obvious. Irregular or non-linear keloids are not easily noticed and are also ideal for scarring. 4. Color: A newly healed scar is red and takes several months to fade, which is its natural healing process. This aspect should also be taken into consideration by the surgeon, as some patients wish to be able to participate in important social events (such as weddings, etc.) once they have fully recovered. Pulsed laser can speed up the fading and cosmetics can perform the masking. Treatment Plan: Turning an annoying scar into an acceptable one Identify the main problem areas according to the above elements and target the repair according to the problems that exist. Limitations of wound healing Be sure to talk to your patient about this problem before the procedure, not as an excuse for problems after the fact. Department: small scar after healing of the upper lid and red lip, poor healing of the anterior chest and joint areas; Genetic factors: check for scar proliferation in other areas and find out if the patient has a keloid; intraoperative hormone injections in the incision are necessary for this group of patients. Age: children during the growth period are prone to hyperplastic scarring, and around 12 years old is recommended for this type of patients. Basic skills: fine wound closure techniques 1. Appropriately wide subcutaneous release can reduce the tension of the incision and avoid “cat ear” deformity at the end of the incision. 2, layered tension-free closure, to achieve this effect try to use subcutaneous sutures with long absorption time. 3. Subcutaneous sutures are essential to take up all the tension, and the skin is completely aligned after suturing. 4, The wound tension is only 10% of normal skin when the sutures are removed 1 week after surgery, and only 75% at 6 weeks, so it is crucial to use sutures with long absorption time (such as Polyglactin or Polydioxane). 5. The skin edge is turned out to prevent depressed scarring, and the sutures are sutured with attention to the needle entering and leaving the skin all vertical. 6. Proper subcutaneous suturing technique (Figure 4). Scar repair Figure 4 Key points of subcutaneous suture: suture with a small amount of dermis medial to the cut edge, with the needle in and out of the needle position all in the deep dermis 7. Vertical mattress suture with the most precise alignment on both sides of the blade can be used in areas where it is difficult to ectropion (such as the tip of the nose) or small flaps (Z-flap), see Figure 5. F Figure 5 Vertical mattress suture 8. The most preferred method of suturing linear incisions is the continuous locking edge suture (Figure 6), which is fast, precise , good ectropion, keeping in mind that the suture needle enters and exits the skin surface vertically. Fig. 6 Side continuous locking suture 9. Try to use small sutures, generally 7-0 for the eyelid and 6-0 for the face. 10. Remove the sutures 5-7 days after surgery to prevent the appearance of suture marks. Common scar repair methods Scar excision suture: 1. Shuttle excision linear (curve) suture; 2. Split excision with 6-12 weeks interval. W scar irregularity technique Z-formation (Figure 7), W-formation, geometric closure (Figure 8, 9). Key points of geometric closure: 1. Ensure that the length of each side of the geometric figure does not exceed 5 mm; 2. Preserve the underlying scar tissue when excising the scar; 3. The skin should be free of sutures after dermal suturing to ensure that the skin edge is turned out. Figure 7 A Upper lip whistle deformity; B Z-plasty to increase the vertical length of the upper lip (red lip with simultaneous V-Y-plasty) Figure 8 Geometric closure design with one side of the incision as a mirror image of the other side Figure 9 Geometric closure method to disperse the scar line and turn it into an inconspicuous scar Repair of avulsed flap Traumatic injury including avulsed flap may have problems with the thickness of the incision or flap after healing, and the repair of this type of scar requires excision of the marginal part of the skin that does not match the surrounding The repair of this type of scar requires excision of mismatched margins, Z or W shaping to irregularize the scar, and thinning and repositioning of the flap (Figure 10), usually by uncovering the flap at the desired thickness and thinning the basal bed with a scalpel or scissors (Figure 11). Figure 10 An avulsion wound flap requires both scar irregularity and flap thinning Figure 11 “Pin cushion” deformity (A) is improved by thinning the flap base (B) Local flap w flap better matches the color and texture of the surrounding skin than a free flap graft (Figure 12). Figure 12 Wider frontal scar repaired by advancing the flap Adjunctive techniques for scar repair Fixation – the less tension on the incisional scar, the less chance it has of becoming a proliferative or wide scar, and splinting in the perioral or articular area is necessary. Pressure – can counteract re-contracture (Figure 13) Figure 13 Stent placed to prevent re-contracture after Z-plasty and composite flap grafting for nostril deformity Hormone injections – commonly used trimethoprim, formulated in concentrations of 10 mg/L to 40 mg/L, when injected Start with small doses and inject 2-3 times at 3-4 week intervals, taking care not to inject into the subcutaneous fat. Silicone patch – it can flatten the scar and improve the appearance of hyperplastic scar, the mechanism is unknown, it needs to be used for several months. Laser – Pulsed dye laser can treat erythema and hyperplastic scar; Fraxel laser can promote skin collagen synthesis; CO2 laser can achieve the effect of skin resurfacing. Skin grinding – good treatment effect after 8 weeks of scar formation, see Figure 14. Figure 14 Skin grinding effect for irregular keloid scars When it is determined that scar repair is to be performed, the goal of scar repair should first be clarified, and the determination of the surgical plan should not be limited to simple excision and suturing; then the local nature of the treatment (e.g., age, etc.) should be explained to the patient, and no Then explain to the patient the local nature of the treatment (e.g. age, etc.) and not to take shortcuts; and finally use adjunctive treatment measures such as dermabrasion in order to achieve the best treatment results.