Today, in the arsenal of modern dermatocosmetology there is a wide range of methods to correct various aesthetic skin imperfections - chemical peels, mechanical dermabrasion, laser restoration, microdermabrasion, contour plastic. and others. Nevertheless, new trends and technologies in the beauty industry are constantly evolving and evolving.
This trend is especially characteristic of hardware methods, primarily laser medicine. The use of lasers, first in dermatology and then in cosmetology, has an effective cycle. More than 25 years have passed since the appearance of one of the newest barrier treatments - selective photothermolysis. The pioneers in this field, the Americans RR Anderson and JA Parrish, predetermined the fate of fractional lasers in medicine, making them indispensable in such aesthetic treatments. skin defects such as capillary hemangiomas. Port wine stains, hypertrichosis, tattoos, rosacea, pigmentation disorders, photography, wrinkles, etc.
Modern skin cleansing methods
We live in a time when more people are aging than ever before. And given that many of them lead active lives, one of the most important problems in aesthetic medicine is the fight against aging skin.
Plastic surgery is able to rejuvenate the shape of the face by removing excess skin. But at the same time, the skin still changes over time (aging due to age) or external factors (photography). It is also important that most patients want to look young without surgery.
What method should be used to affect the skin in this situation and what should happen for real rejuvenation?
All the methods that can be used to improve the appearance of the skin are based on one principle - it has a traumatic effect on the skin caused by fibrosis, which causes it to tighten and tighten.
Currently, dermatocosmetology uses three main types of skin effects:
- chemical stimulation - chemical coatings with acids (trichloroacetic, glycolic, etc. );
- mechanical stimulation - mechanical dermabrasion using needles, microdermabrasion, mesotherapy, fillers, subcision;
- thermal stimulation - laser ablation, thermolysis using lasers and broadband light sources, radiofrequency ablation, fractionation methods.
Chemical stimulation
Historically, acid peeling was the first method of skin rejuvenation. The principle of peeling is the partial (as with surface peeling) or almost complete (as with medium and deep peeling) destruction of the epidermis, damaging fibroblasts and dermis structures. This damage activates an inflammatory reaction (stronger, more volume of destruction), which leads to additional production of collagen in the skin.
However, to achieve the desired result, you have to sacrifice the peeling epidermis. Experiments with burns have misled many by "proving" that the epidermis is a self-renewing organ that repairs damaged areas quickly. area. Due to this, the peeling became more aggressive against the epidermis for a while (for example, deep phenolic peeling), and finally the accumulated problems forced the experts to realize this savagery. a method that eventually results in thinning of the skin.
Proponents of the deep shell ignored the problems that arose. Their essence has led to the thinning of the epidermis due to the destruction of the papillae of the dermis and the weakening of nutrition, and a significant reduction in the number of cells in the thorny layer. with what before peeling. Decreased barrier function of the stratum corneum leads to a decrease in skin hydration. (Therefore, after a long period of deep peeling, almost all patients experience severe dryness of the skin. ) At the same time, light peels (using trichloroacetic and fruit acids) did not live up to expectations of effective skin tightening.
Mechanical stimulation
Of the methods of mechanical stimulation of evolutionary changes in the skin, dermabrasion (at a speed of v; rotation of cutters up to 100, 000 rpm) using rotating devices deserves special attention. Currently, modern Schumann-Schreus devices are used (Germany)
The method can be used only in a surgical hospital, because the procedure requires anesthesia, postoperative treatment of the wound surface, a special toilet for the eyes and mouth, as well as devices. to feed patients (postoperative edema, which occurs 2-3 days after the procedure, because it makes it difficult to open the eyes and mouth).
The method is very effective, but unfortunately there is a high risk of complications during mechanical dermabrasion:
- postoperative hyperemia;
- appearance of areas of depigmentation due to the destruction of melanocytes when passing through the membrane of the cutting basement;
- wound surface infection;
- itching (if the incision is too deep into the skin)
All of the above have identified a limited application of this method in clinical practice.
Thermal stimulation
Ablative repair
Since the late 1980s, lasers have been used to rejuvenate the skin through multiple layers of tissue ablation. Careful, low-traumatic removal of the surface layer of the skin using a carbon dioxide laser stimulates the synthesis of collagen, the amount of which increases several times after the procedure. Then it is gradually reorganized.
The most effective was the use of a CO2 laser, which showed the effect of compressing the skin when exposed to a deep heat to all layers of the dermis. The method, called "laser dermabrasion" or "laser", could not be opposed to any other skin rejuvenation method available at the time (Figure 1).
Figs. 1. Traditional laser skin rejuvenation scheme (laser dermabrasion)
However, CO2 lasers also cause a number of complications. In addition, further research shows that such a profound effect on the dermis stimulates the formation of more fibrous tissue than to promote a new, normal synthesis. directed collagen [5]. Advanced fibrosis can make the skin unusually pale. Collagen synthesized after treatment, like any collagen formed at the wound site, is revived after a few years. As a result of thinning, the epidermis, which is formed as a result of atrophy of the papillary layer of the skin, begins to appear fine wrinkles on the skin. Due to the weakening of the barrier function of the stratum corneum, the skin's moisture level decreases and it looks atrophic.
Erbium-aluminum-ytrium garnet-erbium lasers appeared shortly after. The advantages of erbium lasers such as a smaller thermal penetration depth (erbium lasers up to 30 microns, CO2 lasers - up to 150 microns) and (consequently) the risk of combustion and tissue carbonization, as well as relative cheapness (compared to carbon dioxide lasers) attracted the attention of many experts.
However, as experience has been gained with these two types of devices, there has been a growing consensus among experts that CO2 lasers are more efficient [6]. Despite the negative effects of laser dermabrasion described above, carbon dioxide remains indispensable for the repair of non-surgical wounds. In addition, surgery can be considered as an alternative to skin tightening - exposure to just one CO2 laser from all methods of correcting it can actually cause it. shrinkage of collagen with visible clinical lifting effect.
The problem with all of the above methods is that they often "sacrifice", that is, they cause significant damage to the epidermis. To rejuvenate your skin and look really young, you need a perfect epidermis with natural dermis papillae, good hydration, normal skin tone and elasticity. The epidermis is a very complex, high-level specialized organ up to 200 microns thick, and it is our only protection from the effects of adverse environmental factors. Therefore, whatever we do to rejuvenate the skin, we must make sure that its basic normal architecture is never damaged.
This concept helped to create non-ablative skin correction technology.
Non-ablative repair
The most common devices for correcting non-ablative skin are neodymium (Nd-YAG) and diode lasers, as well as broadband light sources (IPL). Their principle of action - selective photothermolysis - involves the destruction of heat and structure - they contain a sufficient amount of melanin or oxyhemoglobin. In the skin, these are the accumulation of melanocytes (lentigo, melasma) and microvessels (telangiectasia), respectively. The propagating wavelengths used in non-ablative lasers correspond to the maximum absorption spectra of hydroxyhemoglobin or melanin. The treatment procedure with non-ablative lasers and IPL is very safe, the rehabilitation period is minimal, but such treatment only removes pigment and blood vessels cosmetic defects. In this case, there is a certain thickening of the skin, but the effect is short-lived.
Fractional Skin Reconstruction Techniques
The constant search for new highly effective and safe methods of skin rejuvenation has led to the introduction of a revolutionary technology - laser radiation. The proposed skin rejuvenation method was specifically designed to overcome some of the above difficulties. Unlike "conventional" ablative and ablative laser methods, which are designed to achieve uniform thermal damage to the skin at a certain depth, fractional methods achieve selective microscopic thermal damage in the form of numerous modified columns and leave ineffective areas around these micro wounds. Currently, the industry produces two types of fractional lasers: ablative and ablative.
First, it uses an erbium-based optical fiber that generates radiation at a wavelength of 1550 nm. Fractional lasers form thousands and tens of thousands of microdamages in the form of columns - microthermal treatment zones (MLZ) - diameter 70-150mk to depth 1359 mcm
As a result, about 15-35 skins are photocoagulated in the treated area. Chromophore water for laser. . Coagulation occurs mainly in the lower layers of the epidermis and dermis. Due to its content in the stratum corneum, it remains intact due to the small amount of water and significantly reduces the risk of infection. Due to the small size of the lesion and the short migration distance of keratinocytes, epidermal recovery is accelerated. The healing process is accompanied by mild edema and hyperemia, which appear on days 5-7. The patient practically does not lose social activity.
This technology - fractional photothermolysis (FF) - is a highly effective method of non-ablative fraction skin correction. A course of treatment is prescribed to achieve the desired effect. Depending on the clinical situation, it is recommended to perform 3-6 procedures with an interval of 4-6 weeks. As with any other method of non-ablative skin correction, the final result can be seen only 4-8 months after the procedure (cumulative effect).
In cases where a more aggressive effect on the skin is required - the method of fractional ablation (FA or fractional deep dermal ablation - FDDA) is used to correct wounds, remove deep wrinkles and excess skin.
The split ablation method combines the advantages of a CO2 laser and the fractionation principle of laser radiation. Unlike traditional CO2 lasers, which remove the entire skin surface layer by layer, FA units form a large number of microabsorbents. Zones with a diameter of up to 300 μm (MAL) at evaporation depths between 350-1800 μm (Figure 2).
Thus, during this procedure, the laser beam penetrates into the deeper layers of the skin, destroying the top layer of the epidermis. In terms of efficiency, ablative fraction laser rejuvenation can be compared to plastic surgery, how deep are the resources of this laser beam.
Figs. 2. The principle of operation of the ablative fraction laser: the formation of microablative zones - MAZ (a); Dependence of MAZ formation depth on laser radiation power (b)
As in the case of FF, 15-35% of the skin in the treated area is actually exposed (in some cases up to 70%). Recovery after the FA procedure is faster than layer ablation. Because this is important, part of the epidermis and stratum corneum remain intact. Bleeding from the skin is observed for some time immediately after the procedure, but soon stops (Figure 3 a, b).
Figs. 3. Gradual skin regeneration after fractional ablation procedure: see immediately after treatment (a); every other day (b); After 5 days (c); 14 days (d)
after a procedure
Numerous microbleeds appear in the dermis, causing a complex cascade of changes leading to the production of new collagen. Once the bleeding has stopped, the remaining serous fluid on the skin surface must be removed. Its release is observed within 48 hours after the procedure, until complete epithelialization of the microablative zones. During this period, the patient uses special external wound healing agents. It usually begins in 3-4 days and increases with swelling and swelling (Figure 3 c). By day 7, these events gradually decrease and erythema remains the only noticeable side effect (Fig. 3d). The duration of erythema depends on the parameters of laser exposure and the characteristics of skin vascularization. According to the author's observations, erythema does not last more than 3 months.
The patient's loss of social activity after the FA procedure lasts between 5 and 10 days.
Careful skin care is required to prevent itching and post-inflammatory pigmentation. Decorative cosmetics can be used for 4-5 days. One condition for a good result is the use of sunscreen with a high degree of protection for at least 3 months after the procedure (SPF at least 50). The risk of post-inflammatory pigmentation occurs in 20% of patients and is generally higher in patients with skin type IV-V phototypes. Such hyperpigmentation is natural in nature and can last from 1 week to 3 months, depending on the depth of treatment and the area of the treated area. To prevent this, external agents based on hydroquinone (4%) and tretinoin (0. 1%) are prescribed 1-2 weeks before and 2 weeks after the procedure. The main factors that affect the facial skin after the FA procedure are: increased shrinkage and reduction of the skin, smoothing of the surface, wrinkled skin, as well as skin affected by acne scars, reduction of dyschromia, porosity.
This method has also been tested by the author and colleagues to eliminate stretch marks on the skin. As can be seen from clinical studies, the method has shown high efficacy in eliminating almost all stretch marks during and after the postpartum period. It was noted that the healing processes in the skin of the body are different from the skin of the face.
skin straightening mechanism when using fractional lasers
Let's look at the mechanisms of skin correction when using fractional lasers.
Aseptic inflammation develops in the area of micro-wounds that occur after exposure to the laser. As aggressive as laser exposure may be, the inflammatory response that actually causes post-traumatic release is more pronounced with growth factors and infiltration of damaged tissues with fibroblasts. The resulting reaction is automatically accompanied by an explosion of cell activity, which inevitably causes the fibroblasts to begin to produce more collagen and elastin. The skin straightening process involves three classic stages:
- Stage I - change (tissue inflammation). It starts immediately after the damage;
- Stage II - proliferation (tissue formation). It begins 3-5 days after injury and lasts about 8 weeks;
- Stage III - tissue repair. It lasts from 8 weeks to 12 months.
It should be noted that all three stages of skin repair are observed both after fractional photothermolysis and after fractional ablation. However, in the first case, the damaging effects of the laser are moderately aggressive, resulting in an inflammatory cascade change that is never too wild.
After being exposed to a fragmented ablation laser, a completely different picture is observed. The trauma caused by this laser destroys the blood vessels and the blood cells are released into the surrounding tissue along with the serum. The mechanism of full-fledged regeneration - pha changes begin - aseptic inflammation develops. Platelets released from damaged blood vessels play an important role in activating blood clotting and releasing chemotoxic factors. in turn, other platelets, leukocytes and fibroblasts are involved. Leukocytes, especially neutrophils, are involved in the cleansing of destroyed tissues, removing necrotic tissue fragments partially destroyed by phagocytitis. microepidermal necrotic debris (MENO) appears on the surface of the skin in the form of microscopic debris consisting of epidermal and dermal tissue substrates and melanin.
The proliferative phase begins after about 5 days. During this period, neutrophils are replaced by monocytes. Monocytes, keratinocytes and fibroblasts continue to affect growth factors and at the same time are under the influence of them. Stimulate the growth of keratinocytes and the growth of the epidermis and the release of growth factors necessary to stimulate collagen production by fibroblasts. At this stage, new blood vessels form and the extracellular matrix is formed intensively.
The final, reconstructed, recovery phase after exposure to a fragmented laser lasts several months.
On the 5th day after injury, the fibrobectin matrix "adapts" along the axis where the fibroblasts are located and where collagen is formed. Growth factor (TGF-ing is a potent chemotoxic agent for fibroblasts) plays an important role in the formation of this matrix, as well as other growth factors. The main form of collagen in the early stages of wound healing is type III collagen (this type of collagen is in the upper layer of the dermis, below the basal layer of the epidermis). The longer the replacement phase, the more type III collagen will be produced, but in any case, its amount reaches a maximum 5 to 7 days after the damage. Collagen type III is gradually replaced by collagen over a year Type I, which strengthens the firmness of the skin. Blood circulation gradually normalizes, the skin becomes smoother and acquires a natural color.
Comparative analysis of laser skin correction methods
Summarizing the above, we bring to your attention a diagram showing the relationship between the effectiveness and safety of laser skin cleansing methods.
Advantages of fragmented road rejuvenation methods. The advantages of fractionation methods used in clinical practice are as follows:
- minimal skin damage. Histological examination after the procedure shows an increase in the number of papillae in the dermis, which characterizes the changes in the skin as a productive renewal;
- effective rejuvenation: thickens the skin, significantly (400% (! )) increases the production of collagen and elastin;
- short healing time: on average 3 days later and 7-14 days after PA;
- minimal risk of hyperpigmentation;
- Ability to perform the procedure in patients with thin skin;
- ability to have a therapeutic effect on any part of the body;
- Possibility of application of mild types of anesthesia: only local anesthesia is used with fractional photothermolysis; a combination of conduction and infiltration anesthesia is required for fractional ablation;
- Absence of telangiectasia (in many places it is impossible to repair them due to rupture of blood vessels).
Main indicators of fractional treatments
Tips for fractional photothermolysis:
- Increased skin density in the early stages of aging. The FF procedure is relatively easy and can be performed without fear. Therapeutic effect can affect the neck, décolleté, arms, abdomen, thighs, mammary glands;
- skin photos;
- hyperpigmentation, melasma;
- hypertrophic scars;
- stretch marks.
Tips for fractional ablation:
- Wrinkles of varying severity - from fine lines to strong pronunciation (in the form of skin);
- Loss of skin elasticity and firmness with age;
- Excessive skin on eyelids, neck, face (as an alternative to plastic surgery);
- uneven skin texture;
- skin photo;
- acne scars;
- cicatricial deformation of the skin after injuries, operations;
- hyperpigmentation: melasma, lentiginosis, spotted pigmentation, etc.
- vascular dyschromia;
- skin extension marks;
- actinic keratosis.
Finally, a few words about the prospects for the use of laser technology in aesthetic medicine. We need to respect the manufacturers as they begin to pay more attention to the safety of medical procedures using lasers. My technology is evolving. However, the safety of the method has often been sacrificed to increase its effectiveness. Or vice versa. A compromise has been found in a new principle of delivering laser radiation to the tissue. It should be noted that the types of lasers remained the same: erbium, carbon dioxide, neodymium. This shows it:
- First, laser skin cleansing is considered the most effective today;
- Second, the range of aesthetic and dermatological problems solved by these methods is very large - from skin rejuvenation to the treatment of congenital and acquired skin pathologies;
- Third, with the advent of fractional technologies, the safety and effectiveness of treatment have become known in advance.