Deep II, Superficial II, Scar Removal and Retention Points What we usually call “scars” is the medical term for “scarring”, which is actually a normal phenomenon of tissue repair in the human body. Why are deep or large wounds more prone to scarring? It has to do with the all-powerful stem cells. All-powerful stem cells lose their ability to regenerate and repair themselves after they differentiate into functional cells of specific tissues. However, considering that people may be injured, various organ tissues still retain some tissue stem cells in case of emergency. The stem cells in the skin tissue are located right at the junction of epidermis and dermis in the basal layer of the epidermis and the papillary layer of the dermis, and have the ability to self-divide and repair the epidermis. (Skin can be divided into epidermis and dermis from superficial to deep, and dermis contains skin appendages such as hair, sebaceous glands, sweat glands, as well as blood vessels, lymph, nerves, and muscles [1].) When skin trauma or burns involve above the basal layer of the epidermis and the papillary layer of the dermis (such as more superficial abrasions), the skin can be repaired by the proliferation of the remaining epidermal stem cells and the skin stem cells of hair follicles, sweat glands and other skin appendages in the dermis to participate in the repair, and skin injuries of this degree can heal without leaving a scar. However, when the injury reaches deep into the dermis, the wound can only rely on the proliferation of stem cells from skin appendages to form epithelial islets, which can then be fused and repaired. However, more repair work of damaged tissue structures (dissolving and absorbing necrotic tissues localized to the injury and filling tissue defects) is undertaken by granulation tissue (i.e., repair tissue composed of new capillaries and fibroblasts), and fibroblasts within the granulation tissue produce a large number of collagen fibers, and by the late stage of repair the granulation tissue filling the wound is transformed into collagen fiber-based scar tissue, and tissue repair is declared complete [ 2]. Therefore, whether or not the deep dermis is injured is the cut-off point for scar generation or not, as well as the medical cut-off point for superficial and deep second-degree burns (scalds) [3]. However, this is not absolute. A more superficial wound, which is not treated properly leading to wound infection, can deepen the original superficial injury and thus damage the deeper dermis, which can then also leave a scar. It must be noted that it is impossible to have a deep skin injury without leaving a scar. Qi Qin’s agency announced Qi Qin’s injuries stating, “Qi Qin suffered 8% burns on his entire body, all concentrated on his face, neck and back, with facial burns covering 60% of his entire face and deep II degree burns.” [4] If the injuries announced by Qi Qin’s agency are true, with common medical knowledge, Qi Qin’s facial skin scarring is certain. The statement by his agent that “his (Qi Qin’s) face can recover completely! [5]” is not supported by medical evidence. Can scarring be invisible? Unfortunately, the formed scar cannot be eliminated, and the available treatments can only prevent excessive scar proliferation as much as possible, make the scar less visible, and minimize the impact of the scar on joint movement. Thus, the treatment modalities chosen for different types of scarring in different areas vary from patient to patient. You may have noticed that some burn patients use a variety of compression bandages, wear compression garments, and wear compression headgear during the recovery period. This method of preventing and treating scar growth by applying continuous compression to the scar area with an elastic fabric is called compression therapy (compression therapy). When the scar is subjected to a constant pressure of at least 24 mm Hg, tissue ischemia occurs, which increases the release of local lactic acid, which in turn increases the release of cytoactive substances (such as prostaglandin E2, collagenase, gelatinase B, etc.) that soften and flatten the scar and facilitate scar remodeling. Compression therapy is simple and easy to perform, with precise results, fewer side effects and high cost effectiveness, and is an important part of scar treatment, and is now widely used in the treatment of various burn and scald scars. However, this therapy requires patients to adhere to it for a long period of time, using pressure for at least 18 hours a day for at least 6 months to have an effect. This therapy is really a bit inconvenient in case of tiny scars caused by daily trauma [6][7]. For de novo scarring, non-ablative laser therapy is a good option. Its specific wavelength pulsed dye laser selectively destroys the new microvasculature within the scar and also causes collagen destruction and remodeling, resulting in flattening and reddening of the newly formed scar. However, it is not effective in the treatment of scars that have been formed for more than 1 year, and this laser treatment has a weak effect on tissues other than blood vessels [6]. In addition, surgical excision, laser ablation, radiation therapy, encapsulation, local injection of glucocorticoids or chemotherapeutic drugs, and topical medications can improve the scar condition. The specific choice of method needs to be made under the guidance of a physician. The love and hate of scar scar scar tissue can fill and connect tissue defects for a long time, so that the tissue organ remains intact. In addition, although the scar is not as strong as normal skin in terms of tensile strength, this filling and joining is also quite strong and allows the tissue organ to remain strong. However, scar tissue also has a detrimental side to the organism. Among them are surgical incisions and deep second-degree burns that tend to heal as proliferative keloids (medically, keloids are divided into four categories: superficial keloids, proliferative keloids, atrophic keloids, and keloids.) . Because the collagen fibers produced by fibroblasts are inelastic, large proliferative keloids located on the back of the hand, wrist, neck, and joint areas are equivalent to splints and can impede joint movement. After several months of scar formation, the water within the scar is gradually lost, the gradually increasing collagen fibers undergo glassy degeneration, the cells and capillaries in them are further reduced, and the scar may undergo more pronounced contraction, further aggravating the impaired joint movement. In addition, scarring adhesions can affect the function of tissues and organs to varying degrees, and excessive proliferation of scar tissue forms hypertrophic keloids that can affect the patient’s appearance [2]. How can scar formation be prevented? The most fundamental aspect of scar prevention is to prevent the occurrence of trauma, especially severe burns and scalds. For those who are “scarred”, try to avoid unnecessary injurious operations on high-risk areas such as the head, face and upper body, such as tattoos and piercings. For wounds that have already occurred, the first thing to do is to treat the wound early. For clean wounds, debridement sutures should be done within 6 hours, and for facial trauma, special sutures should be performed in plastic surgery department as soon as possible. After the sutures are changed regularly, the stitches are removed in due time, and attention is paid to the cleanliness of the wound to prevent infection. After the stitches are removed or the wound is initially healed, early compression therapy and massage are performed. Topical medications such as silicone, vincristine, Conrad or Xyrtec can be used after healing of smaller wounds or to help soften the scar and inhibit scar proliferation [8].