Skin is the body's largest organ and has many important functions. It’s frequent exposure to the sun and other environmental irritants can cause significant damage. Fine lines and wrinkles, pigment changes, skin laxity and even skin cancers represent some of the consequences of years of exposure of the skin to the environment. Aging, nutrition, genetics, medications and smoking can also produce skin changes that can age a person and rob them of self-confidence and feelings of vibrancy. Photoaging refers to skin damage caused by chronic sun (ultraviolet light) exposure. Photoaging is the major offender in the premature development of an aged appearance.
The ultimate results of chronic skin damage are texture and pigment changes. Keratinocyte (the major cell type in our skin) melanocyte (the pigment cell in our skin) and collagen/elastin (the major proteins in our skin) changes are the pathologic hallmarks of skin aging.
The most effective approach to addressing chronic skin changes, in addition to daily skin care regimens, is skin resurfacing. Skin resurfacing is the process of removing the top layers of skin, the damaged skin, resulting in induction of skin repair mechanisms and replacement of the damaged skin with new skin cells and new collagen and elastin formation. After skin resurfacing procedures, the epidermis (the outer layer of skin) becomes thicker and more youthful and the dermis (the deeper layer of skin) becomes tighter because of new collagen and elastin formation. The result of these repair mechanisms is an improvement in pigmentation, tone and laxity. Skin resurfacing can dramatically reverse signs of photoaging and significantly improve the appearance of scars. The 3 skin resurfacing techniques which have shown the most consistent results and best safety profile are: dermabrasion, chemical peels and laser therapy.
Conditions improved with skin resurfacing:
Fine lines and wrinkles
Vertical lines around the mouth that cause “lipstick bleed”
“Crow’s feet”- the lines emanating from the outer aspect of the eyes
Skin laxity in the upper and lower eyelids
Brow spots, uneven complexion
Pre-cancerous skin lesion
Types of Skin Resurfacing
Dermabrasion and Dermaplaning entails use of a rotary tool (diamond fraise) to mechanically remove the top layers of skin. The dermabrasion injury is followed by skin natural repair mechanisms that result in formation of a new epidermal layer and new collagen formation in the dermis. Dermabrasion and dermaplaning are good for smoothing raised scars and for improving the appearance of fines lines and wrinkles. Dermabrasion can also be used to address pigment changes and to even complexion. Dermabrasion, although effective, is highly user dependent as the user determines the depth of the injury in all locations where the procedure is performed. Considerable experience is required for efficacy and safety. Practitioners must exercise considerable judgement with respect to how deep into the dermis the fraise must travel in the areas of the face, which have different thickness and signs of photoaging. If an area with thinner skin, such as the eyelids, is treated with the depth of fraise travel that is appropriate for thicker skin, such as that around the mouth, significant scarring can occur. Downtime after deeper dermabrasion can be significant since there is confluent removal of the outer skin layers which requires epithelial repopulation from the skin appendages- sweat glands, hair follicles and sebaceous glands.
Chemical Peel- Chemical peels employ caustic chemicals to exfoliate the outer layer of skin. Commonly used chemicals include acids (trichloroacetic acid, glycolic acid, lactic acid, etc.), phenol (carbolic acid- a weak acid) and croton oil. The alpha- and beta-hydroxy acids (glycolic, lactic, salicylic and maleic acid) produce the lightest peel depths, followed by trichloroacetic acid which produces a deeper peel. The mixture of croton oil and phenol produces the deepest peel. There are lighter peels that are available over-the-counter. Light peels produce modest results and require frequent retreatments to maintain the improvement. Deeper and more durable peels are associated with more significant pain and therefore require topical anesthetics and sometimes sedation. Peels, like dermabrasion, produce confluent removal of the outer layers of skin, therefore, deeper peels are associated with significant downtime. Also like dermabrasion, the efficacy and safety are practitioner dependent- if the peel is not deep enough the results with suffer and if too deep scarring can occur.
Laser- Lasers use light of different wavelengths to target constituents of the skin. The skin constituents absorb the laser light and the absorption causes tissue change. The absorption causes thermal, mechanical or chemical changes in the skin. Thermal and mechanical changes produce skin rejuvenation. The light is absorbed by skin constituents called chromophores. The important chromophores are water, hemoglobin and pigment (melanin). Hemoglobin absorption of laser energy allows lasers to treat vascular lesions (spider/leg veins, telangiectasias, vascular lesions, etc.) and absorption by pigment allows treatment of pigmented lesions (moles) and is responsible for laser hair removal. Absorption by water produces tissue vaporization with resultant skin tightening, texture improvement and wrinkle reduction. Lasers can also be used to improve the quality of acne and post-operative scars. Lastly, tattoo ink also acts as a chromophore giving lasers the ability to remove tattoos.
The fact that laser therapy is chromophore-specific, and therefore tissue-specific, gives laser great specificity. Tissue specificity is responsible for a lasers’ great safety and efficacy profile. As mentioned above, only light/energy that is absorbed by the chromophore/tissue constituent produces tissue change, the rest of the tissue is spared from injury. There different types of lasers. The different types of lasers produce light of different wavelengths. The wavelength is the laser’s selective signature, giving the laser the ability to selectively interact with the chromophore/tissue. For example, a pulsed dye laser operates in the wavelengths of 585 or 595 making its selective chromophore hemoglobin. Therefore, a pulsed dye laser is ideal for treating vascular lesions such as port wine stains. Alexandrite lasers produce light at a wavelength of 755 making it a good choice for targeting melanin and therefore treating pigmented lesions (e.g. tattoos) and freckles. Erbium-YAG (Er:YAG) and C02 lasers emit light with wavelengths that target water as a chromophore. Because water is 70% of the weight of soft tissue, targeting water can have significant tissue effects. When water is heated to 100oC it is converted to water vapor leading to fragmentation, vaporization and ablation of tissues. Heat is also produced in this zone of injury which results in collagen shortening and immediate tissue tightening. The ablated tissue is replaced by new collagen and elastin formation in the dermis and new epithelial cell growth in the epidermis. Er-YAG and CO2 lasers, because they can ablate (vaporize) tissue, are called ablative lasers.
Ablative vs. Nonablative Lasers
Wrinkle reduction and skin tightening can be achieved with both ablative and non-ablative lasers. Nonablative lasers rejuvenate tissues by heating the dermis producing collagen remodeling resulting in wrinkle reduction and skin tightening. Melanin, hemoglobin and water are all potential chromophores for non-ablative lasers. As with all lasers, absorption by the chromophore produced tissue change. With non-ablative lasers, the changes occur in the dermis, the outer layer of skin (epidermis) is spared. Because the epidermis is not ablated (vaporized), recovery is much faster than with an ablative treatment. Nonablative lasers heat the skin stimulating collagen production improving skin texture and tone. The treatments are less-invasive but also less effective than ablative treatments. Nonablative lasers also require multiple treatments to produce their effects but downtime is minimal.
Ablative lasers, Er:YAG (2940 nm) and C02 (10,600 nm) lasers target water as their chromophore. They vaporize the epidermis and the outer dermis stimulating new skin formation. The skin that is produced is tighter, less wrinkled and demonstrates a better complexion. Because the outer layer of skin is removed, downtime can be significant. The skin looks abraded and requires specific skin care to prevent infection and for moisture control. Depending on the type of laser used the downtime can last from weeks to months. Full field laser resurfacing ablates the skin in a confluent pattern with no skip or spared areas. Because all of the outer layers of skin are removed over a relatively large area, wound healing and epithelial cell re-population must occur through migration of epithelial cells from the skin appendages (hair follicles, sebaceous/oil gland and sweat glands) that remain deeper in the dermis after the laser ablation. This process takes weeks to occur and is followed by redness that can last for months. Full field ablative laser therapy is highly effective but is less attractive to people who work full time and prefer a limited “weekend” downtime. Because of the extended downtime, full field ablative laser therapy has fallen out of favor.
Fractional ablative laser resurfacing was developed to address the issues of downtime associated with full field procedures. With fractional therapy the laser energy is delivered to the tissues in columns. The tissue that comes in contact with the column of energy is ablated but the surrounding skin is spared. At the center of the column is the “zone of ablation.” In this area, the old, wrinkled, damage skin is vaporized to be replaced by new and revitalized skin. The newly developed skin also undergoes contraction resulting in tissue tightening. The area around the zone of ablation is referred to as the “zone thermal injury.” This zone of thermal injury is analogous the tissue change seen with non-ablative laser resurfacing which results in new collagen formation and further tissue tightening. Both Er:YAG and CO2 lasers can deliver fractionated ablative laser energy. In general, Er:YAG lasers deliver shallower columns with less thermal injury. Both lasers can produce excellent rejuvenation, but Er:YAG lasers may require more “passes” to produce similar results when compared with CO2.
Fractional ablative skin resurfacing is currently the state of the art in non-invasive skin rejuvenation. The technology provides more control than deep dermabrasion and deep chemical peels, improving safety. There are many companies who manufacture fractional Er:YAG and CO2 lasers; there are significant differences which can affect outcomes.
Deka DOT/SmartXide Laser
Deka is an Italian medical laser manufacturer and produces and markets lasers in 80 countries worldwide. Deka manufactures the innovative DOT/SmartXide laser. The SmartXide laser provides power, control and speed; it is a truly tunable laser. The Deka DOT laser allows the user to “tune” the intensity of the column of energy delivered to the tissue. Increasing the power increases the depth of the area of ablation to allow treatment of deeper scars and wrinkles. The power can be decreased to treat finer lines and wrinkle and crepey skin. Dwell time is the amount of time that the laser energy is in contact with the tissue. The dwell time correlates with the “thermal injury” discussed above which promotes new collagen formation and tissue tightening. This thermal injury also produces “coagulation” which acts to decrease bleeding related to the ablation. Fractional CO2 lasers treat a “fraction” of the skin, sparing the surrounding skin. The Deka DOT allows for a high level of control in determining the fraction of tissue treated. The distance between the columns (pitch) can be changed very precisely, which determines the fraction of the tissue that is ablated. By changing the distance between the ablation columns, 1.7-31.8% of the skin in the treatment area can be ablated. The control provided by adjusting these variables offers customization of treatment plans to fit the specific deformity and the amount of downtime the patient can accept. The Deka laser can also be used to perform full field treatments if the fractionation controls are disabled. Full field therapy has higher risk and downtime but may still make sense for certain areas such as for deep wrinkles around the mouth. Pulse stacking is another feature of the Deka laser that affords customization of treatments to specific situations. With stacking, a 2nd, 3rd, 4th or 5th pulse can be given, with each pulse increasing the depth of the ablation. Pulse stacking is used to treat post-operative and acne scars. The Deka laser also has a robust and versatile scanner which can be used to plan treatments that can be designed to reach all areas of the face and neck to ensure that every angle, curve and extent of skin can be treated. Control and customizability are the hallmarks of the Deka DOT laser allowing treatment that can truly be designed to address a variety of skin conditions with a downtime that can be determined by the patient.
Laser therapy has consistently been a popular procedure in a plastic surgeon’s practice. Ablative laser skin resurfacing can be performed as a standalone procedure and is also employed in facelift surgery around the eyes and mouth, areas that are not specifically addressed with facelift procedures. Laser skin resurfacing consistently has high patient satisfaction. The downtime associated with deeper and more extensive treatments can produce significant dissatisfaction among many patients. However, with the development of fractional resurfacing and recent advancements in fractional laser technology, treatments can be customized to design treatment protocols that can address the finest line to the deepest fold with a recovery period that can be determined by the patient.
The Role of the CO2 Laser and Fractional CO2 Laser in Dermatology; Laser Therapy, 2014 Mar 27; 23(1): 49–60
Dermatologic and Cosmetic Procedures in Office Practice E-Book By Richard P. Usatine, John L. Pfenninger, Daniel L. Stulberg, Rebecca Small