What is a fractional laser? Fractional laser is not a laser, but a mode of laser operation, as long as the diameter of the laser beam (spot) is less than 500 μm, and the laser beam is regularly arranged in a dotted pattern. The ultra-pulsed exfoliative CO2 fractional laser can instantly heat the water in the tissue to more than 100 °C and vaporize the epidermis and the dermis (scar) at different depths when acting on the skin, resulting in vaporization pits. Due to its high peak energy, small thermogenic side-damage zone, precise vaporization of tissues, light damage to surrounding tissues, and healing of laser wounds in 3 to 5 days, as well as less possibility of complications such as hyperpigmentation or hypopigmentation, it improves the shortcomings of the non-fractional mode of laser with greater adverse reactions (scarring, redness, long recovery time, etc.) and less obvious efficacy, presenting better treatment results. What is the real fractional technology? Numerous studies have shown that fractional pattern, fractional density, micropore size and depth of micropores directly affect the treatment results. Therefore, how to control the fractional pattern to achieve the best treatment effect is an important development direction of fractional laser technology. Some fractional laser manufacturers use porous mask technology to project ordinary laser onto the skin to produce fractional effect, the advantage is to greatly reduce the production cost, the disadvantage is that the fractional output is relatively coarse, and cannot accurately control the fractional output, poor clinical efficacy as well as narrow indications. The latest fractional output technology uses computerized intelligent laser scanning technology, through the computer and precision optical scanner, doctors can directly control the fractional laser output pattern, including fractional size, density, distance, shape, the diameter and depth of each micro-hole, making fractional laser treatment more suitable for the needs of patients, causing damage is truly minimally invasive and controllable, enhancing the treatment effect and reducing side effects. The fractional laser using computerized intelligent laser scanning technology is the real fractional laser. The fractional laser system used in the Burn Unit of Changhai Hospital is the real fractional technology. What is the principle of fractional laser treatment for scarring? Fractional CO2 laser is a gas laser, the principle of action is “focal photothermal action”, through the fractional laser to produce an array of tiny beams, after acting on the skin to form a number of three-dimensional columnar structure of the tiny thermal damage area, each tiny damage area is surrounded by undamaged normal tissue, its keratinocytes can quickly crawl, so that it heals quickly. The collagen fibers and elastic fibers can be proliferated and rearranged, so that the content of type I and III collagen fibers is close to the normal ratio, resulting in structural changes of the pathological scar tissue, which gradually softens and regains elasticity. The main absorbing group of fractional laser is water, which happens to be the main component of the skin. It can cause contraction and denaturation of dermal collagen fibers by heating, and induce trauma healing reaction in the dermis, produce orderly deposition of collagen and promote collagen proliferation, thus improving skin elasticity and reducing scarring, and its main mechanisms include: 1. Damage and inhibit vascular tissue in scar tissue; 2. Vaporize and remove scar tissue; 3. Inhibition of fibrous tissue production and excessive proliferation; 4. Induction of fibroblast apoptosis. What are the advantages of minimally invasive fractional laser treatment for burn scars compared to surgical excision of scars? For small burn scars, fractional laser treatment does not require hospitalization and can be performed on an outpatient basis; the operation time is short, usually from a few minutes to 10 minutes; the recovery period is short, with the scar recovering in 2-4 days, without affecting normal work and life; the damage to the treated scar is small, with no or only a small amount of bleeding. For large scars, conventional surgery often requires skin removal and implantation, and patients with large scars often face the situation of no skin available, and even if there is skin available, they face the possibility of re-growing scars in the skin removal area; fractional laser treatment for large scars does not require skin removal, which reduces a lot of surgical pain, significantly shortens surgery and hospitalization time, and can quickly relieve pain and itching symptoms. Fractional laser treatment can improve the appearance of keloid scars significantly by doing treatment once every three months for more than one year. Can fractional laser treat the itching and pain of keloid scars? Fractional laser treatment can treat painful scars caused by burns and wounds, and the itching and pain can generally be improved 1-2 days after treatment. Our clinical practice shows that fractional laser has an efficiency of over 90% in treating itching and pain of keloid scars, and can reduce the pain or itching score from a maximum of 5 to 1-2 within 3 days, which is very effective. Many scar patients who had “sleepless nights” due to pain and itching before treatment were able to “sleep soundly” immediately after treatment. Can fractional laser treat scarring after a cesarean section? Yes. Scarring after a cesarean section is essentially scarring caused by trauma (surgical incision). About two to three weeks after the surgical incision is scarred, the scar begins to grow, which is red, purple, hard and protrudes from the skin. After about three months to a year, the scar growth may stop and the scar may flatten and soften and turn dark brown in color. Itching and pain will occur at the same time as the scar proliferates. Especially during heavy sweating or weather changes, the itchiness is often so severe that it must be scratched to the point of blood. Early application of fractional laser treatment can inhibit the proliferation of keloid scars after cesarean section surgery and quickly suppress the itching and pain caused by keloid proliferation, usually the itching and pain can be improved in 1-2 days after treatment. Generally, treatment is given once every 3 months, and 4 times is a course of treatment. Adhering to the treatment for more than one course of treatment, the appearance of the scar will be significantly improved. Can fractional laser treat stretch marks? Stretch marks witness the beautiful transformation of a mother, but they also become a big enemy of the mother’s beauty. Stretch marks generally appear in the umbilicus and pubic bone area of pregnant women, and are some light red or purple irregular cracks. These markings will gradually shrink and become silvery white after a pregnant woman gives birth, and eventually the skin becomes saggy. Essentially, there are three main problems with stretch marks: first, pigment loss, which gives stretch marks a white streaky appearance and is the main reason for the aesthetics of the abdomen; second, varying degrees of skin laxity and atrophy, which gives the skin a wrinkled paper appearance; and third, breakage of collagen fibers. Therefore, the primary treatment aim is to restore the normal color of the skin, and secondly to eliminate the wrinkled paper-like appearance of stretch marks. Fractional laser can be applied to very difficult stretch marks. By stimulating the skin tissues, the damaged skin can re-produce collagen and rearrange it so that the skin can be restored to a tender state, helping to reduce the appearance or extent of stretch marks. After a few sessions, it can make the stretch marks look less noticeable by lightening their color and significantly narrowing their width. Can fractional laser treat hyperpigmentation after burns? Some superficial post-burn scars manifest mainly as hyperpigmentation. These include depressed scar pigmentation left over from acne and superficial scar pigmentation due to trauma and burns, as well as scarring around surgical implants and local pigmentation of implants. These are symptoms that cannot be addressed by surgical procedures. Ultra-pulsed CO2 fractional laser treatment for skin scar pigmentation uses the principle of focal photothermal action to vaporize the scar tissue containing melanocytes and eventually achieve dermal reconstruction, and the total efficiency can reach 77-100%. After surgery, attention to sun protection and the use of hydroquinone cream and other medications to assist in the treatment can promote the efficacy and reduce the pigment rebound recurrence. Is fractional laser suitable for early (hyperplastic) or late (mature) stage of scar treatment? The fractional ultra-pulsed CO2 laser differs from the regular CO2 laser in that it uses high peak short pulse technology, which enables the laser to maintain high peak energy throughout the ultra-short pulse period, and can vaporize the target tissue accurately in an instant, and the time it takes to act on the target tissue is shorter than the heat diffusion time to the surrounding tissue. Therefore, the thermal damage to the tissue can be minimized. Although multiple micro-damaged areas with columnar structure are formed on the scar, a part of the normal scar tissue is preserved, which will initiate the skin’s own repair and reconstruction procedure due to the injury, therefore, fractional laser is suitable for the treatment of superficial scar, hyperplastic scar and mild contracture scar in all stages. How soon after surgery or injury can I start fractional laser treatment? Traditionally, it is believed that the timing for surgical scar treatment should be chosen between 6 months and 1 year after the injury when the scar is mature and stable, because the boundaries of the scar tissue are clear, the blood supply is reduced and the surgical excision bleeds less, before that, non-surgical anti-“scar” means are mostly used to “treat” the scar. “Before that, non-surgical anti-scar treatment (prevention of scar proliferation), such as compression dressing to reduce the blood supply of scar tissue, steroid hormone intra-scar injection to promote the degradation of scar collagen, silicone gel products and topical medication, are often used, but the results obtained are often disappointing. Advances in ultra-pulsed CO2 fractional laser technology combined with in-depth research on scar pathology have prompted us to change the traditional scar treatment schedule. Most scholars now advocate advancing the time of laser scar treatment to 1 week after wound removal or 1 month after surgery, when the wound has already healed and is in the early stage of scar proliferation, which can be treated more safely and effectively by introducing drugs such as tretinoin with an exfoliative fractional laser. The results are better and greatly reduce the possibility of subsequent traditional surgery to remove the scar. What are the contraindications of fractional laser? Scarring; psychiatric patients; active vitiligo and psoriasis, systemic lupus erythematosus; pregnancy or lactation; photosensitivity; taking isotretinoin in the past 1 year, current or previous active cold sore or herpes simplex virus infection; other laser treatments within 3 months should be reported to the doctor, who will evaluate whether a new laser treatment is acceptable.