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Eualuation of CO2 fractional laser effect on the skin by confocal microscopy
Abstract
The physical principle of the efficacy and the reduced risk of CO 2 fractional lasers is the generation of controlled columns of thermal damage, the so-called Microthermal zones (MTZ) or DOT. These require certain specific characteristics of emission so to ensure the maximum efficacy and minimum unwanted skin damage. The stimulation effect of collagen and skin rejuvenation are due to the depth of the thermal damage in dermal layers, which triggers the generation of new collagen and repair tissue. The objective of this study has been to evaluate the effect of a CO2 fractional laser (SmartXide, Deka) on the epidermal and dermal layers and the use of confocal microscopy together with the fractional mode (DOT on) system, to determine in vivo the maximum depth of the laser thermal effect. The fractional mode, with also an interlaced scan mode, uses the "Stack" parameter to multiply the depth of the pulses in tissues up to the deepest layers while the parameters of potency remain unchanged, and to determine the spot diameter in skin tissue from the surface to the depth. Our study has demonstrated that the SmartXide CO2 fractional laser, with the use of conservative settings, emits pulses with a regular shape in the whole columns. By changing the emission to penetrate into depth (DOT On mode, Stack On), it is possible to highlight the thermal damage to a depth up to more than 400 μm.
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This study evaluates the efficacy and safety of a novel fractional CO(2) laser device for improving facial rhytids, hyperpigmentation, enlarged pores, skin laxity, and acne scarring. Subjects (n= 15) were treated three to five times at 3-week intervals. Biopsy specimens were used to evaluate healing response and neocollagenesis. Clinical improvement was rated on a quartile rating scale from digital photographs. Subject discomfort during treatment was evaluated on a scale of 0 to 5. Fourteen subjects who completed the study achieved good to excellent improvement in overall appearance, with 60% rated excellent. Improvement in photodamage was good to excellent in 92% of subjects, and reduction in rhytids was good to excellent in 85%. A total of 79% of subjects achieved good to excellent improvement in pore sizes and skin laxity. Subject discomfort during treatment was 3.0 +/- 0.7. Erythema persisted for 2-3 days, and subjects resumed normal activities 1-2 days after the procedure. Histological slides after a single treatment showed new collagen formation. The SmartSkin fractional CO(2) system (Cynosure, Inc., Westford, MA, USA) provides significant improvement for the treatment of facial wrinkles, hyperpigmentation, pore size, and skin laxity associated with photodamage.
Ablative carbon dioxide resurfacing is the gold standard for treating atrophic acne scarring but is associated with prolonged recovery and many side effects. To address these limitations, newer modalities employing the principle of fractional photothermolysis have emerged.
We undertook a prospective study whereby five Asian patients of skin phototype IV with moderate to severe atrophic acne scarring received two sessions of a fractional carbon dioxide laser 6-8 weeks apart. Treatment parameters were: fluence, 28 J/cm(2); pulse width, 2.5 ms; spot size, 300 microm; penetration depth, up to 500 microm; degree of skin coverage, 20%; single pass. Photographic evaluation was done on the level of improvement according to a quartile grading scale: <or=25% (mild), 26-50% (moderate), 51-75% (marked), >75% (excellent).
At 2 months post-treatment, all five subjects showed some clinical improvement (four: mild improvement; one: moderate improvement). The treatment was well tolerated. All patients had erythema, which lasted for a mean of 6 days. No other complications were observed.
Our study has shown that in Asians the fractional ablative carbon dioxide laser produces mild to moderate improvement in acne scarring with the advantage of a quick recovery period with minimal adverse effects.
Previous laser treatments for Poikiloderma of Civatte (PC) (i.e., Pulsed dye, Intense Pulsed Light, KTP and Argon) are limited by side effect profiles and/or efficacy. Given the high degree of safety and efficacy of ablative fractional photothermolysis (AFP) for photoaging, we set out to assess the efficacy of PC with AFP.
A prospective pilot study for PC in 10 subjects with a series of 1-3 treatment sessions. Treatment sessions were administered at 6-8 week intervals with blinded physician photographic analysis of improvement at 2 months post-treatment. Evaluation was performed of five clinical indicators, erythema/telangiecatasia, dyschromia, skin texture, skin laxity and cosmetic outcome.
The number of treatments required for improvement of PC ranged from 1 to 3, with an average of 1.4. For erythema/telangiecatasia, the mean score improved 65.0% (95% CI: 60.7%, 69.3%) dyschromia, 66.7% (95% CI: 61.8%, 71.6%), skin texture, 51.7% (95% CI: 48.3%, 55.1%) and skin laxity, 52.5% (95% CI: 49.6%, 55.4%). For cosmetic outcome, the mean score improved 66.7% (95% CI: 62.6%, 70.8%) at 2 months post treatment.
In this prospective study, AFP was both safe and effective for the treatment of the vascular, pigmentary and textural components of PC. The degree of improvement observed in wrinkling, creping and laxity after AFP has not been reported with prior laser treatments for PC.
Lasers and light-based treatments are extremely useful and now standardized techniques in the management of different stages of photoaging. To obtain the most successful results, protocols involving single or combination systems can be used, depending on skin photodamage. In the last years, the trend is to choose noninvasive or minimally invasive treatments, with the aim of reducing the risk of side effects, complications, and downtime. Selective photothermolysis obtained with lasers and with intense pulse light, which is presently considered the most suitable technique by a growing number of authors, is an extremely valid procedure, in particular in types I and II, according to the Glogau classification. Photodynamic therapy is another effective tool in photoaging treatment, especially in the presence of precancerous conditions. In mild and severe photoaging, ablative laser resurfacing is a particularly successful technique, although requiring a very skilled hand. The new systems, such as fractional photothermolysis, seem to be the very next future to face up to resurfacing procedure with high efficacy and less risks. Obviously, lasers and light-based treatments alone might not be sufficient to control all aging symptoms. For this reason, any another treatment (botulinum toxin, filling agents, chemical peels, systemic and topic antioxidants) can be used in combination to improve the final clinical outcome.
The theoretical model of CO2 laser tissue interaction appeared to be too simplistic. To explain the reactions seen in skin, a more complex model was needed. We hoped to correlate the clinical-histologic patterns of CO2 laser tissue interactions.
The Ultrapulse CO2 laser was used on normal and pathologic skin conditions. Clinical observations were correlated with histologic examinations of biopsies.
It was possible to demonstrate cavitation at the dermal-epidermal junction 2-3 diameters beyond the actual spot of CO2 laser contact with the skin. Dermal heat damage was seen as homogenization of collagen 1-2 diameters beyond the spot of laser contact. This flow of energy laterally at the dermal-epidermal junction and vertically down the skin follicles was both clinically beneficial and detrimental. Beneficially, superficial skin lesions separated at this junction and were easily removed. The heat coagulation of the dermis facilitated lesion removal without bleeding. The clinician had a better view of the pathology and could find focal zones of deeper pathology that could be easily re-treated. Detrimentally, this extended damage delayed wound healing and led to persistent erythema.
These clinical-histologic correlations have provided a better understanding of CO2 laser tissue interactions in skin. It has been possible to take advantage of these findings to remove pathologic skin conditions more efficiently.
Resurfacing laser is one of the alternative treatment for cutaneous facial rejuvenation. Results are mainly good to excellent, but complications do occur with variable frequency.
The purpose of this study was to identify and report the complications they occurred during eight years laser resurfacing and to study their possible avoidance. The author experiences are discussed in conjunction with a review of published reports.
A retrospective analysis and chart review was performed in 749 patients who underwent cutaneous laser resurfacing with CO2 and Erbium laser by a single operator. Side effects and complications relating to infection, postoperative healing, pigmentary changes, and scarring were tabulated.
The most common complication observed was postoperative erythema, which occurred in all patients. Hyperpigmentation was seen in 32% of patients and must be precociously treated. Dermatitis occurred in 10.6% of patients. Hypopigmentation and infections are rare (<1%).
Although laser resurfacing is a safe and effective method of facial rejuvenation, the cosmetic surgeon must be aware of the various complications that may be encountered. Prompt recognition of complications and appropriate management provide the best opportunity for an acceptable aesthetic outcome.
Ablative laser resurfacing is an effective treatment for atrophic acne scars. However, it often induces complications such as edema, prolonged erythema, scarring and hyperpigmentation. Therefore, a new concept of laser treatment called fractional photothermolysis has been designed to create microscopic thermal wounds to achieve skin rejuvenation treatment of atrophic acne scars. This study was designed to prospectively evaluate the use of a technique similar to fractional photothermolysis using only the standard CO2 laser without the fractional laser device in the treatment of atrophic scars and demonstrates it as a safe, effective and economical treatment option. Clinical improvement was achieved in all 35 patients with minimal adverse effects.