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Comparison of four different lasers for acne scars: Resurfacing and fractional lasers
Accepted Manuscript Comparison of 4 Different Lasers for Acne Scars: Resurfacing and Fractional Lasers Hi-Jin You, MD, PhD, Deok-Woo Kim, MD, PhD, Eul-Sik Yoon, MD, PhD, Seung-Ha Park, MD, PhD, MBA PII:
S1748-6815(15)00604-X
DOI:
10.1016/j.bjps.2015.12.012
Reference:
PRAS 4859
To appear in:
Journal of Plastic, Reconstructive & Aesthetic Surgery
Received Date: 1 October 2015 Revised Date:
3 December 2015
Accepted Date: 22 December 2015
Please cite this article as: You H-J, Kim D-W, Yoon E-S, Park S-H, Comparison of 4 Different Lasers for Acne Scars: Resurfacing and Fractional Lasers, British Journal of Plastic Surgery (2016), doi: 10.1016/ j.bjps.2015.12.012. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Comparison of 4 Different Lasers for Acne Scars:
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Resurfacing and Fractional Lasers
Hi-Jin You, MD, PhD; Deok-Woo Kim, MD, PhD; Eul-Sik Yoon, MD, PhD
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and Seung-Ha Park, MD, PhD, MBA
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Department of Plastic Surgery
Korea University College of Medicine, Seoul, Korea
Correspondence:
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Short Running Head: comparison of lasers for acne scars
Seung-Ha Park, MD, PhD, MBA
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Department of Plastic Surgery Korea University Anam Hospital
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73, Inchon-ro, Seongbuk-gu, Seoul, 02841 Korea Tel: +82-2-920-5775 Fax: +82-2-922-7437 E-mail: [email protected]
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Comparison of 4 Different Lasers for Acne Scars: Resurfacing and Fractional Lasers
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Summary
Background: Acne scars are common and cause cosmetic problems. There is a multitude of treatment options for acne scars, including dermabrasion, chemical peeling, and fillers, but the advent of laser
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technology has greatly improved treatment of acne scars. Although there are several laser systems available, studies comparing their efficacy are limited. This study compares the results of treatments
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using resurfacing (CO2; Er:YAG) versus fractional (nonablative fractional laser [NAFL]; ablative fractional laser [AFL]) lasers.
Methods: A retrospective photographic analysis of 58 patients who received laser treatment for facial atrophic acne scars was performed. Clinical improvement was assessed by six blinded investigators
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using a scale graded from 0 to 10. Adverse events were also noted.
Results: Mean improvement scores of the CO2, Er:YAG, NAFL, and AFL groups were 6.0, 5.8, 2.2, and 5.2, respectively. The NAFL group showed a significantly lower score than the other groups. The
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mean number of treatments was significantly greater in the fractional laser groups than in the resurfacing laser groups. The resurfacing laser groups had a prolonged recovery period and high risk
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of complications. The Er:YAG laser caused less erythema or pigmentation than the CO2 laser. Conclusions: Acne scars may best be treated with the Er:YAG laser and AFL. Resurfacing lasers may be more effective than fractional lasers, but longer postoperative downtime and a higher potential for adverse events must be tolerated. Although the CO2 laser, Er:YAG laser, and AFL improved the acne scars, the CO2 laser had a greater downtime. Three consecutive AFL treatments are as effective as a single treatment with resurfacing lasers, with shorter social downtime periods and less adverse effects.
Keywords: acne scar; laser resurfacing; ablative fractional laser; nonablative fractional laser
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Introduction
Acne scars, appearing as multiple depressions, cause cosmetic problems. Unfortunately, the
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psychosocial impact of acne scars can be profound. They manifest on visible body parts of children and adolescents, who are both vulnerable and sensitive to their appearance. They can lose confidence, causing limitations on self-esteem, social interactions, and daily activities. 1
While the most effective means of addressing acne scars is to prevent their formation
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through good control of acne, there are many therapeutic modalities to improve their appearance. Chemical peeling, surgical excision, subcision, punch grafting, dermabrasion, and tissue augmentation
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with a variety of fillers have been used, but their effectiveness has been insufficient. Each of these treatments is limited by their adverse effects, including incomplete scar removal, scar worsening, and pigmentary alteration, and by unsatisfactory results. With recent developments in laser technology, however, the problems that arise with conventional acne treatment are minimized, and since the
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operator can control the depth of peeling according to the depth of the scars, satisfactory results can be obtained without complications. 1
Laser skin resurfacing is being employed as an effective tool for improvement of acne scars.
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The goal of laser treatment for acne scars is to smooth the texture of the scar, and to stimulate collagen production within the atrophic area. Recontouring of facial atrophic scars with use of
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resurfacing lasers has become very popular in recent years. Resurfacing lasers work through selective ablation of water-containing tissue, and offer predictable and reproducible vaporization of tissue, as well as better control compared with dermabrasion. However, complications associated with resurfacing lasers include a long recovery time and considerable risk of adverse effects, such as infection, pigmentation, and discomfort. To avoid such unwanted outcomes, fractional lasers have been developed. The first-developed fractional laser system involved a 1,550-nm Er:Glass laser, which was categorized as a nonablative fractional laser (NAFL) system. Laser energy delivered to the skin induces microscopic volumes of thermal injury deep down to the reticular dermis, known as microscopic thermal zones (MTZs).
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Subsequently, ablative fractional laser (AFL) systems, which 3
ACCEPTED MANUSCRIPT adopt carbon dioxide (CO2) or erbium-doped yttrium aluminum garnet (Er:YAG) as a medium, have been developed to leap over NAFLs. In contrast to NAFLs, AFLs not only create similar columns of thermal coagulation through the epidermis and dermis, they also vaporize the stratum corneum. 3 Previous studies have compared outcomes of various lasers used to treat acne scars; however, 4-7
Therefore,
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there has never been a direct comparison of outcomes among 4 different laser systems.
the aim of this study was to evaluate and compare the effects of resurfacing (CO2, Er:YAG) versus
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fractional (nonablative, ablative) lasers in treatment of atrophic acne scars.
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Materials and Methods
Patients
A retrospective review was performed of the medical records and photographs of patients
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who underwent laser treatment for facial atrophic acne scars between 1996 and 2014. All patients had completed the medical treatment of acne. This study was approved by the institutional review board. Patients were excluded if there were no documented follow-ups or postoperative photographs longer
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than 6 months after laser treatment. Patients who underwent concomitant punch biopsy or combined laser treatments also were excluded. Evaluation at a minimum follow-up of 6 months was chosen to
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allow time for healing and scar improvement. Specific information was recorded for each patient, including age at time of laser treatment, length of follow-up, and number of treatments.
Laser Treatments: Devices and Techniques The study used 4 types of laser device: 1. Resurfacing lasers A. 10,600-nm ultrapulse CO2 resurfacing laser (Coherent) B. 2,940-nm Er:YAG resurfacing laser (Contour Er:YAG; Sciton) 2. Fractional lasers 4
ACCEPTED MANUSCRIPT A. 1,550-nm erbium-doped fiber NAFL (Fraxel SR 1500; Reliant Technologies) B. 10,600-nm CO2 AFL (eCO2; Lutronic) Skin preparation was done using retinoic acid (0.025%-0.1%), hydroquinone (4%), and hydrocortisone (0.5%-1%) for pre- and postlaser treatments. Prelaser treatment was done 2 to 4 weeks
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prior to laser therapy. Postlaser treatment was started after re-epithelialization took place.
The authors marked the acne scars using an operating pen to identify them before they were distorted by injection of local anesthetics. The area that underwent laser treatment included the cheek
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in all cases; the temple and glabella were involved in some cases. For full-face laser resurfacing, general endotracheal anesthesia was used; for focal facial area, intravenous sedation with nerve block
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and local anesthesia were applied in combination. As an intravenous sedative, midazolam (2-5 mg) was used, and as a local anesthetic, 2% dental lidocaine was used. Fentanyl was administered intravenously in order to control pain during resurfacing. For fractional laser treatment, topical anesthesia using 5% lidocaine cream was applied under occlusive dressing for 1 hour and subsequently rinsed off. Before laser treatment, the facial area was cleaned using normal saline, drops
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of a local anesthetic eye solution (0.5% Alcaine) were applied, and eye shields were inserted.
Ultrapulse CO2 Resurfacing Laser
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For the first pass of the laser, the power was set at 10 to 60 W, with the pulse energy at 300 to 500 mJ. After the first pass, the skin formed a white layer; when this layer was peeled off, pinkish
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skin appeared with exudates, and ice-pick and rolling depressed scars appeared more clearly. The desiccated tissue was wiped clean using moist saline-soaked gauze, and using a 3-mm handpiece, more-depressed lesions were treated according to their depth. The depressed center of each scar was accurately punched out using 5 to 10 continuous passes at the same site. Oozing was cleansed using dry gauze before the second pass. For the second pass of the laser, the power and density were set at 250 to 400 mJ, which was weaker than that of the first pass. In all cases, resurfacing was repeated 2 to 4 times according to scar severity.
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ACCEPTED MANUSCRIPT Er:YAG Resurfacing Laser Er:YAG laser resurfacing was performed in dual mode to vaporize the epidermis. Dual mode was conducted using 100- to 200-µm ablation and 25- to 50-µm sequential coagulation. The first pass was repeated 1 to 2 times according to the skin thickness. After this procedure, a second pass of 25-
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µm ablation and 50-µm coagulation was delivered to the dermis 2 to 3 times.An additional laser punch out was applied to more-depressed lesions.
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NAFL
The treatment area was primed using a FDA–certified water-soluble tinted tracking blue dye
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solution in order to accentuate scar contours and to guarantee laser-skin contact. The tint allows for the laser’s intelligent optical tracking system to detect contact with the skin and to adjust the treatment pattern with respect to handpiece velocity. After treatment, the blue dye was removed using a mild cleanser. The laser was delivered to the area at an energy of 30 mJ/MTZ, at a total density of 2,500 MTZs/cm2. Treatment levels varied from 4 to 6. Ten passes were performed on all patients. Treatment
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parameters were adjusted based on scar severity and each patient’s tolerance. Three to 5 successive treatment sessions were performed at intervals of 3 weeks.
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AFL
Treatment sessions consisted of single or double passes using pulse energy of 50 mJ, power
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of 30 W, and density of 150 spots/cm2. The treatment protocol was modified slightly depending on each individual scar’s characteristics (depth, width, and type). The laser procedure was repeated every 2 months, and a total of 3 to 5 sessions were performed in each patient. If the patient was satisfied with the results obtained after the third session, a fourth session was not performed.
Postlaser Care After laser resurfacing, initial wound treatment comprised compressive dressing with wet gauze for 1 hour. The wet dressing was changed to occlusive dressing when oozing was decreased. On 6
ACCEPTED MANUSCRIPT approximately the seventh to tenth day, when wound healing was almost complete, postlaser skin care began; at the same time, sunscreen cream (SPF, 30-50) was used. Because the skin becomes dry after resurfacing, moisturizing cream was recommended. Postfractional laser care consisted of hydrocolloid dressing (DuoDERM), sunscreen cream,
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and moisturizing cream. Postlaser treatment using hydroquinone and retinoid acid was started after 3 to 4 weeks if postinflammatory hyperpigmentation occurred.
Oral acyclovir (200 mg, 2 times daily) was prescribed only to those patients who had a
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history of recurrent Herpes simplex infections.
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Evaluation
Photographs were taken using identical camera settings, lighting, and patient positioning at every follow-up visit. Photographs were assessed by a group of 6 individuals comprising 3 plastic surgeons and 3 nurses. Clinical assessments were completed separately for each side of the face independently, and were made according to improvement score (0-10 grading scale: 0 = no
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improvement, 10 = excellent improvement) by comparing pre- and postoperative photographs. Mean score for each laser was calculated and evaluated for statistical significance. Patients also reported adverse effects of treatment, including bleeding, oozing, scaling,
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crusting, erythema, edema, and posttherapy hyperpigmentation. Adverse effects and recovery times
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were recorded at each treatment session and follow-up visit.
Statistical Analyses
All data analyses were performed using IBM SPSS version 20.0. Demographic variables, such as sex, age at time of treatment, and number of treatments, were summarized by means of summary statistics. Simple descriptive statistics, such as frequency, mean, median, SD, minimum, and maximum, were calculated for all outcome variables. The Mann-Whitney U test was used to determine whether there was any significant difference in clinical improvement among the laser systems. Differences were considered statistically significant at p values of <0.05. 7
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Results
A total of 58 patients (35 men, 23 women) with Fitzpatrick skin type IV were included in the study. Mean age at time of treatment was 27.2 ± 6.3 years (range, 18-45 years). Patients were
The demographic profile of the patients is provided in Table 1.
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followed up for a minimum of 6 months to a maximum of 54 months (average, 10.3 ± 8.2 months).
Laser resurfacing was performed once in most of the patients. Six patients in the CO2 group
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and 2 in the Er:YAG group who had severe acne scars underwent 2 to 3 repeated laser treatments at 6to 12-month intervals. Fractional laser treatments were repeated every 3 weeks (NAFL) or 2 months (AFL) until scar appearance became acceptable and no additional improvement was expected, or until the patient discontinued clinic visits. Mean numbers of treatments are shown in Table 1 and Figure 1.
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There was no significant difference in mean number of treatments between the CO2 and Er:YAG groups, or between the NAFL and AFL groups. Mean number of treatment session per patient was significantly greater in the fractional laser groups compared with the resurfacing laser groups.
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Clinical improvement in all patients occurred between 3 and 8 weeks after treatment. Mean improvement score of the CO2, Er:YAG, NAFL, and AFL groups were 6.0, 5.8, 2.2, and 5.2,
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respectively (Table 1, Figure 1). There was no significant difference in mean score among the CO2, Er:YAG, and AFL groups, though a slightly higher score was seen in the CO2 group (p > 0.05). Mean improvement score of the AFL group closely approximated that of the resurfacing laser groups, indicating that the outcome of AFL was similar to that of ablative resurfacing. The NAFL group, however, showed a significantly lower mean score compared with the other 3 groups (p < 0.05). Although patients treated with the NAFL clearly had less social downtime, they were less satisfied with the treatment results. Figure 2-5 demonstrates examples of pre- and postoperative photographs in each group. Adverse effects included pain during treatment and posttreatment bleeding, oozing, erythema, 8
ACCEPTED MANUSCRIPT and pigmentation. All patients reported that treatment-associated pain was generally tolerated. Patients reported more severe pain with resurfacing lasers than with fractional lasers. Erythema and edema persisting for several days was observed in the resurfacing laser groups. Re-epithelialization occurred in all patients in less than 2 weeks. Risk of transient pigmentation was higher with resurfacing lasers
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than with fractional lasers; however, neither scarring nor pigmentary changes were seen in any patient
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(Table 2).
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Discussion
Acne is the most common skin disease. 8 Most patients with acne leave it as is or handle it in the wrong way, forming atrophic scars, which are often difficult to treat and can have devastating psychosocial effects. Acne scars can appear in various forms all over the face, and can be classified
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into 4 patterns as follows: (1) rolling depressed scars, (2) ice-pick scars or prominent craters, (3) conglomerated depressed scars, and (4) a combined pattern.
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Atrophic acne scars are dermal
depressions that result from inadequate replacement of deleted collagen fibers. The textural changes
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caused by collagen destruction and dermal atrophy are often permanent. Histologically, these scars are unique because of the relative absence of skin appendages and elastic fibers.
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The irregular
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arrangement of collagen fibers is thick in the dermis layer, with almost the same thickness as the surrounding tissue below the epidermis. Intradermal scars with irregularly arranged collagen bundles are located deeply (Figure 6a). 1 Dermabrasion has a more cutting effect on the surrounding normal skin than on the scar, and the elevation effect on the depressed scars is less than expected. With dermabrasion, depressed scars improved, but deep or ice pick scars showed no improvement, and depigmentation, whitening, and change of the skin contour with exudation occurred (Figure 6b). Chemical peeling is better, in that it has an equal peeling effect on the depressed scar and the surrounding normal skin, but its effect is limited. With chemical peeling, control of peeling depth is difficult, and complications may be 9
ACCEPTED MANUSCRIPT encountered (Figure 6c). The combination of laser resurfacing and laser punch-out gives more effective results by removing deep-seated scars, with less sacrifice of normal tissue (Figure 6d). Resurfacing lasers are one of the most effective treatment modalities for improvement of acne scars. Our previous study of acne scars treated using the ultrapulse CO2 laser reported a 72%
better than even-depth resurfacing for improvement of deep acne scars.
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excellent improvement of scar appearance, and also introduced the laser punch-out method, which is 1 9
An alternative to the CO2
laser is the Er:YAG laser, which is 12 to 18 times more efficiently absorbed by water. Both lasers are
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efficacious in treatment of acne scars, but the CO2 laser has superior results, while the Er:YAG laser is better tolerated with less associated downtime, fewer adverse events, and less postoperative recovery
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time.
More recently, treatment of atrophic acne scars has been performed using fractional laser devices (Figure 6e, 6f). 10 Clinical improvement of atrophic acne scars with AFLs and NAFLs results from collagen contraction and neocollagenesis. Our previous study demonstrated that both AFL and NAFL systems provide skin tightness through collagen production, but skin shrinkage was more
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noticeable in AFL-treated skin compared with NAFL-treated skin. 11 Significant clinical improvement has been shown when fractional photothermolysis is applied to atrophic acne scars. published studies compared the effects of an NAFL with an AFL on atrophic scars.
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2,6,12-25
Two
These studies
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concluded that clinical improvement with the AFL was equal to or greater than that with the NAFL. However, some bias would significantly affect the outcomes. Several recent review articles
7,10,20,24,26
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have shown that NAFL therapy provided limited efficacy in treatment of deep acne scars, and required multiple treatments for an appropriate clinical effect. AFL had more efficacious results in patients with moderate to severe acne scars. In addition, fewer treatment sessions are required with AFL than with NAFL.
Although conventional resurfacing lasers using either a CO2 or Er:YAG laser is the gold standard for laser resurfacing, it can be associated with an undesirable adverse event profile, including high risk of infection and dispigmentation, as well as a prolonged recovery period, compared with fractional laser treatments. Unlike resurfacing lasers, which can yield significant results after just one 10
ACCEPTED MANUSCRIPT treatment, fractional lasers require multiple treatments to achieve satisfactory outcomes. Recent studies have tried to define the optimal treatment parameters that would allow fractional lasers to approach the efficacy of conventional ablative lasers. 12,21,27-32 Well-conducted comparative studies using standard protocols are few in number, and have
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rarely included acne scars. This is the first study to compare the 4 different laser systems used to treat acne scars: resurfacing (CO2, Er:YAG) versus fractional (nonablative, ablative). Mean improvement scores showed that CO2 resurfacing lasers were the most effective in improving atrophic scars.
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However, they were associated with adverse effects and complications, including pigmentary changes and prolonged erythema. Er:YAG resurfacing lasers were as effective as CO2 resurfacing lasers, with
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shorter social downtime periods and fewer adverse effects. Active acne responds well to NAFLs, which eliminate acne with an anti-inflammatory effect, but are less clinically effective for scar improvement. A single treatment with AFLs may be less effective than resurfacing lasers, but these can be used in patients desiring minimal downtime. The present study demonstrated that 3 successive treatment sessions at 2-month intervals with AFLs provided clinical outcomes equivalent to those with
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conventional resurfacing lasers. In terms of adverse events and recovery time, our findings are comparable with those of previous studies that included various treatments for acne scars. Compared with conventional resurfacing lasers, AFL therapy improves acne scars with a shorter recovery period
procedure.
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and decreased risk of infection and pigmentation. Therefore, it is the best option for a weekend
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Comparing these four laser systems after a single session is inherently flawed, since a series of fractional laser treatments is generally needed to rival the effects of one resurfacing laser treatment. Nevertheless, we compared the effect of these lasers by dividing the mean improvement score by the mean numbers of treatments. The data showed scar depth improvement of 50–70% after one treatment session with resurfacing laser therapy. After one treatment with NAFL or AFL therapy, 5% and 20% improvement was estimated, respectively. In clinical practice, factors in choosing a treatment option include not only treatment efficacy, but also risk of adverse effects, recovery time, and pain acceptability. Despite the inconclusive nature 11
ACCEPTED MANUSCRIPT of the equivalent outcomes, several factors, including risk of adverse effects and pain involved, also should be taken into account when a therapeutic option is being considered. It is also important to note that different types of acne scars will respond differently to laser resurfacing. Of all the scar types, rolling scars have been reported to respond best, while ice-pick pitted scars respond worst, to 21,33
If pits or ice-pick scars are the predominant scar type in any individual
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fractional treatment.
patient, he/she is unlikely to be satisfied with fractional resurfacing alone. In order for ablative fractional CO2 laser resurfacing to be safer and more effective, both conventional ablative resurfacing
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and fractional laser therapy are combined to treat moderate to severe acne scars.
There were several limitations to this retrospective study. First, total number of treatment
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sessions and time interval between treatments varied among patients. Mean number of treatment sessions per patient was greater in the CO2 group compared with the Er:YAG group, though it did not reach statistical significance. There may be advantages if the number of treatments is increased because more profound clinical improvement may be noted. Second, the statistical results may be limited by the small and unequal sample size of each group. Nonparametric tests were used for data
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analysis. A prospective controlled randomized study would be required for better comparisons. The third limitation of this study is that analysis was based on assessment of clinical photographs taken prior to each treatment session, rather than at standard time intervals after each treatment. Lastly, the
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grading system is fraught with subjective bias.
Our results do not constitute a conclusive comparison of the 4 laser systems. However, it
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appears that 3 AFL treatments are as effective as a single treatment with resurfacing lasers, without a statistical difference. We recommend the Er:YAG resurfacing laser for patients who can afford to have 10–14 days of downtime, or who can tolerate the social downtime; this laser also has fewer adverse events such as erythema and postinflammatory hyperpigmentation than the CO2 laser. AFL may be used in patients desiring further treatments following laser resurfacing. It is also recommended if the laser treatment disrupts patients’ social activity. NAFLs are less effective in improvement of acne scars, but have therapeutic effects on acute inflammatory acne by reducing redness and inflammation. We believe our study could be used as an essential reference when choosing laser modalities for acne 12
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Conflict of interest statement:
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The authors have no conflicts of interest to disclose in relation to the content of this article.
Financial disclosure statement:
None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this
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manuscript.
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Funding:
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None
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Yuan XH, Zhong SX, Li SS. Comparison study of fractional carbon dioxide laser resurfacing using different fluences and densities for acne scars in Asians: a randomized split-face trial. Dermatol Surg 2014;40:545-52.
33.
Sardana K, Manjhi M, Garg VK, Sagar V. Which type of atrophic acne scar (ice-pick, boxcar, 16
ACCEPTED MANUSCRIPT or rolling) responds to nonablative fractional laser therapy? Dermatol Surg 2014;40:288-300. Park SH. Laser dermatology plastic surgery 2nd ed. Seoul, Korea: Koonja Publishing Inc.;
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Figure Legends Figure 1. Mean clinical improvement scores (*p < 0.05).
treatment (500mJ; 2 passes).
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Figure 2. (a) Before laser treatment and (b) 12 months after 2 sessions of CO2 resurfacing laser
Figure 3. (a) Before laser treatment and (b) 6 months after Er:YAG resurfacing laser treatment
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(ablation mode 100mJ; 2 passes, coagulation mode 50mJ; 3-5 passes).
Figure 4. (a) Before laser treatment and (b) 10 months after 5 sessions of NAFL treatment (30mJ,
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480spots/cm2; 10 passes).
Figure 5. (a) Before laser treatment and (b) 7 months after 2 sessions of AFL treatment (120mJ, 150spots/cm2; single pass).
Figure 6. (a) The epidermis of the acne scar has the same appearance and thickness as the
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surrounding tissue, but a thick collagen bundle of scars exists deep in the dermis. (b) Dermabrasion (c) Chemical peeling (d) Laser resurfacing (e) Nonablative fractional laser; NAFL (f) Ablative
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fractional laser; AFL
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Tables Table 1. Patient demographics
Fractional
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Resurfacing Er:YAG
NAFL
AFL
10,600
2,940
1,550
10,600
17
18
11
12
Male
7
9
9
Female
10
9
No. of patients
Age, y Mean ± SD Range
24 ± 3.9 18-30
No. of treatments 1.6 ± 0.9
Range
29 ± 6.6
18-45
22-36
23-45
1.1 ± 0.3
4.0 ± 1.3
3.4 ± 0.7
1-5
2-4
11.4 ± 7.3
14.0 ± 11.8
6.4 ± 0.9
6.8 ± 1.1
6-32
6-54
6-9
6-9
5.8 ± 1.9
2.2 ± 1.3
5.2 ± 2.1
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Improvement score, mean ± SD
26.7 ± 4.2
1-2
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Range
28.8 ± 8.2
1-3
Follow-up period, mo Mean ± SD
2
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Mean ± SD
10
2
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Wave length, nm
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CO2 ultrapulse
Laser
6.0 ± 2.0
Abbreviations: AFL, ablative fractional laser; CO2, carbon dioxide; Er:YAG, erbium-doped yttrium aluminum garnet; NAFL, nonablative fractional laser.
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Resurfacing
Fractional
CO2 ultrapulse
Er:YAG
NAFL
AFL
Pain
+++
+++
++
+
Oozing
++
++
-
5-10
4-7
1-3 months
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Epithelialization, d
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Laser
+
2-3
2-4 weeks
2-3 days
1-2 weeks
1 month
1-2 weeks
1-2 days
3-4 days
%
80%
60%
10%
20%
Degree
++++
+++
±
+
25
1-2
-
11.5
-14
-4.3
-9
Erythema
Social downtime
-43
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Late collagen contraction, %
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Immediate collagen shrinkage, %
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PIH
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Abbreviations: AFL, ablative fractional laser; CO2, carbon dioxide; Er:YAG, erbium-doped yttrium aluminum garnet; NAFL, nonablative fractional laser; PIH, postinflammatory hyperpigmentation.
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S1748-6815(15)00604-X
DOI:
10.1016/j.bjps.2015.12.012
Reference:
PRAS 4859
To appear in:
Journal of Plastic, Reconstructive & Aesthetic Surgery
Received Date: 1 October 2015 Revised Date:
3 December 2015
Accepted Date: 22 December 2015
Please cite this article as: You H-J, Kim D-W, Yoon E-S, Park S-H, Comparison of 4 Different Lasers for Acne Scars: Resurfacing and Fractional Lasers, British Journal of Plastic Surgery (2016), doi: 10.1016/ j.bjps.2015.12.012. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Comparison of 4 Different Lasers for Acne Scars:
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Resurfacing and Fractional Lasers
Hi-Jin You, MD, PhD; Deok-Woo Kim, MD, PhD; Eul-Sik Yoon, MD, PhD
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and Seung-Ha Park, MD, PhD, MBA
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Department of Plastic Surgery
Korea University College of Medicine, Seoul, Korea
Correspondence:
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Short Running Head: comparison of lasers for acne scars
Seung-Ha Park, MD, PhD, MBA
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Department of Plastic Surgery Korea University Anam Hospital
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73, Inchon-ro, Seongbuk-gu, Seoul, 02841 Korea Tel: +82-2-920-5775 Fax: +82-2-922-7437 E-mail: [email protected]
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Comparison of 4 Different Lasers for Acne Scars: Resurfacing and Fractional Lasers
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Summary
Background: Acne scars are common and cause cosmetic problems. There is a multitude of treatment options for acne scars, including dermabrasion, chemical peeling, and fillers, but the advent of laser
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technology has greatly improved treatment of acne scars. Although there are several laser systems available, studies comparing their efficacy are limited. This study compares the results of treatments
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using resurfacing (CO2; Er:YAG) versus fractional (nonablative fractional laser [NAFL]; ablative fractional laser [AFL]) lasers.
Methods: A retrospective photographic analysis of 58 patients who received laser treatment for facial atrophic acne scars was performed. Clinical improvement was assessed by six blinded investigators
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using a scale graded from 0 to 10. Adverse events were also noted.
Results: Mean improvement scores of the CO2, Er:YAG, NAFL, and AFL groups were 6.0, 5.8, 2.2, and 5.2, respectively. The NAFL group showed a significantly lower score than the other groups. The
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mean number of treatments was significantly greater in the fractional laser groups than in the resurfacing laser groups. The resurfacing laser groups had a prolonged recovery period and high risk
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of complications. The Er:YAG laser caused less erythema or pigmentation than the CO2 laser. Conclusions: Acne scars may best be treated with the Er:YAG laser and AFL. Resurfacing lasers may be more effective than fractional lasers, but longer postoperative downtime and a higher potential for adverse events must be tolerated. Although the CO2 laser, Er:YAG laser, and AFL improved the acne scars, the CO2 laser had a greater downtime. Three consecutive AFL treatments are as effective as a single treatment with resurfacing lasers, with shorter social downtime periods and less adverse effects.
Keywords: acne scar; laser resurfacing; ablative fractional laser; nonablative fractional laser
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Introduction
Acne scars, appearing as multiple depressions, cause cosmetic problems. Unfortunately, the
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psychosocial impact of acne scars can be profound. They manifest on visible body parts of children and adolescents, who are both vulnerable and sensitive to their appearance. They can lose confidence, causing limitations on self-esteem, social interactions, and daily activities. 1
While the most effective means of addressing acne scars is to prevent their formation
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through good control of acne, there are many therapeutic modalities to improve their appearance. Chemical peeling, surgical excision, subcision, punch grafting, dermabrasion, and tissue augmentation
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with a variety of fillers have been used, but their effectiveness has been insufficient. Each of these treatments is limited by their adverse effects, including incomplete scar removal, scar worsening, and pigmentary alteration, and by unsatisfactory results. With recent developments in laser technology, however, the problems that arise with conventional acne treatment are minimized, and since the
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operator can control the depth of peeling according to the depth of the scars, satisfactory results can be obtained without complications. 1
Laser skin resurfacing is being employed as an effective tool for improvement of acne scars.
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The goal of laser treatment for acne scars is to smooth the texture of the scar, and to stimulate collagen production within the atrophic area. Recontouring of facial atrophic scars with use of
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resurfacing lasers has become very popular in recent years. Resurfacing lasers work through selective ablation of water-containing tissue, and offer predictable and reproducible vaporization of tissue, as well as better control compared with dermabrasion. However, complications associated with resurfacing lasers include a long recovery time and considerable risk of adverse effects, such as infection, pigmentation, and discomfort. To avoid such unwanted outcomes, fractional lasers have been developed. The first-developed fractional laser system involved a 1,550-nm Er:Glass laser, which was categorized as a nonablative fractional laser (NAFL) system. Laser energy delivered to the skin induces microscopic volumes of thermal injury deep down to the reticular dermis, known as microscopic thermal zones (MTZs).
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Subsequently, ablative fractional laser (AFL) systems, which 3
ACCEPTED MANUSCRIPT adopt carbon dioxide (CO2) or erbium-doped yttrium aluminum garnet (Er:YAG) as a medium, have been developed to leap over NAFLs. In contrast to NAFLs, AFLs not only create similar columns of thermal coagulation through the epidermis and dermis, they also vaporize the stratum corneum. 3 Previous studies have compared outcomes of various lasers used to treat acne scars; however, 4-7
Therefore,
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there has never been a direct comparison of outcomes among 4 different laser systems.
the aim of this study was to evaluate and compare the effects of resurfacing (CO2, Er:YAG) versus
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fractional (nonablative, ablative) lasers in treatment of atrophic acne scars.
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Materials and Methods
Patients
A retrospective review was performed of the medical records and photographs of patients
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who underwent laser treatment for facial atrophic acne scars between 1996 and 2014. All patients had completed the medical treatment of acne. This study was approved by the institutional review board. Patients were excluded if there were no documented follow-ups or postoperative photographs longer
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than 6 months after laser treatment. Patients who underwent concomitant punch biopsy or combined laser treatments also were excluded. Evaluation at a minimum follow-up of 6 months was chosen to
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allow time for healing and scar improvement. Specific information was recorded for each patient, including age at time of laser treatment, length of follow-up, and number of treatments.
Laser Treatments: Devices and Techniques The study used 4 types of laser device: 1. Resurfacing lasers A. 10,600-nm ultrapulse CO2 resurfacing laser (Coherent) B. 2,940-nm Er:YAG resurfacing laser (Contour Er:YAG; Sciton) 2. Fractional lasers 4
ACCEPTED MANUSCRIPT A. 1,550-nm erbium-doped fiber NAFL (Fraxel SR 1500; Reliant Technologies) B. 10,600-nm CO2 AFL (eCO2; Lutronic) Skin preparation was done using retinoic acid (0.025%-0.1%), hydroquinone (4%), and hydrocortisone (0.5%-1%) for pre- and postlaser treatments. Prelaser treatment was done 2 to 4 weeks
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prior to laser therapy. Postlaser treatment was started after re-epithelialization took place.
The authors marked the acne scars using an operating pen to identify them before they were distorted by injection of local anesthetics. The area that underwent laser treatment included the cheek
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in all cases; the temple and glabella were involved in some cases. For full-face laser resurfacing, general endotracheal anesthesia was used; for focal facial area, intravenous sedation with nerve block
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and local anesthesia were applied in combination. As an intravenous sedative, midazolam (2-5 mg) was used, and as a local anesthetic, 2% dental lidocaine was used. Fentanyl was administered intravenously in order to control pain during resurfacing. For fractional laser treatment, topical anesthesia using 5% lidocaine cream was applied under occlusive dressing for 1 hour and subsequently rinsed off. Before laser treatment, the facial area was cleaned using normal saline, drops
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of a local anesthetic eye solution (0.5% Alcaine) were applied, and eye shields were inserted.
Ultrapulse CO2 Resurfacing Laser
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For the first pass of the laser, the power was set at 10 to 60 W, with the pulse energy at 300 to 500 mJ. After the first pass, the skin formed a white layer; when this layer was peeled off, pinkish
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skin appeared with exudates, and ice-pick and rolling depressed scars appeared more clearly. The desiccated tissue was wiped clean using moist saline-soaked gauze, and using a 3-mm handpiece, more-depressed lesions were treated according to their depth. The depressed center of each scar was accurately punched out using 5 to 10 continuous passes at the same site. Oozing was cleansed using dry gauze before the second pass. For the second pass of the laser, the power and density were set at 250 to 400 mJ, which was weaker than that of the first pass. In all cases, resurfacing was repeated 2 to 4 times according to scar severity.
5
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µm ablation and 50-µm coagulation was delivered to the dermis 2 to 3 times.An additional laser punch out was applied to more-depressed lesions.
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NAFL
The treatment area was primed using a FDA–certified water-soluble tinted tracking blue dye
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solution in order to accentuate scar contours and to guarantee laser-skin contact. The tint allows for the laser’s intelligent optical tracking system to detect contact with the skin and to adjust the treatment pattern with respect to handpiece velocity. After treatment, the blue dye was removed using a mild cleanser. The laser was delivered to the area at an energy of 30 mJ/MTZ, at a total density of 2,500 MTZs/cm2. Treatment levels varied from 4 to 6. Ten passes were performed on all patients. Treatment
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parameters were adjusted based on scar severity and each patient’s tolerance. Three to 5 successive treatment sessions were performed at intervals of 3 weeks.
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Treatment sessions consisted of single or double passes using pulse energy of 50 mJ, power
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of 30 W, and density of 150 spots/cm2. The treatment protocol was modified slightly depending on each individual scar’s characteristics (depth, width, and type). The laser procedure was repeated every 2 months, and a total of 3 to 5 sessions were performed in each patient. If the patient was satisfied with the results obtained after the third session, a fourth session was not performed.
Postlaser Care After laser resurfacing, initial wound treatment comprised compressive dressing with wet gauze for 1 hour. The wet dressing was changed to occlusive dressing when oozing was decreased. On 6
ACCEPTED MANUSCRIPT approximately the seventh to tenth day, when wound healing was almost complete, postlaser skin care began; at the same time, sunscreen cream (SPF, 30-50) was used. Because the skin becomes dry after resurfacing, moisturizing cream was recommended. Postfractional laser care consisted of hydrocolloid dressing (DuoDERM), sunscreen cream,
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and moisturizing cream. Postlaser treatment using hydroquinone and retinoid acid was started after 3 to 4 weeks if postinflammatory hyperpigmentation occurred.
Oral acyclovir (200 mg, 2 times daily) was prescribed only to those patients who had a
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history of recurrent Herpes simplex infections.
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Evaluation
Photographs were taken using identical camera settings, lighting, and patient positioning at every follow-up visit. Photographs were assessed by a group of 6 individuals comprising 3 plastic surgeons and 3 nurses. Clinical assessments were completed separately for each side of the face independently, and were made according to improvement score (0-10 grading scale: 0 = no
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improvement, 10 = excellent improvement) by comparing pre- and postoperative photographs. Mean score for each laser was calculated and evaluated for statistical significance. Patients also reported adverse effects of treatment, including bleeding, oozing, scaling,
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crusting, erythema, edema, and posttherapy hyperpigmentation. Adverse effects and recovery times
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were recorded at each treatment session and follow-up visit.
Statistical Analyses
All data analyses were performed using IBM SPSS version 20.0. Demographic variables, such as sex, age at time of treatment, and number of treatments, were summarized by means of summary statistics. Simple descriptive statistics, such as frequency, mean, median, SD, minimum, and maximum, were calculated for all outcome variables. The Mann-Whitney U test was used to determine whether there was any significant difference in clinical improvement among the laser systems. Differences were considered statistically significant at p values of <0.05. 7
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Results
A total of 58 patients (35 men, 23 women) with Fitzpatrick skin type IV were included in the study. Mean age at time of treatment was 27.2 ± 6.3 years (range, 18-45 years). Patients were
The demographic profile of the patients is provided in Table 1.
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followed up for a minimum of 6 months to a maximum of 54 months (average, 10.3 ± 8.2 months).
Laser resurfacing was performed once in most of the patients. Six patients in the CO2 group
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and 2 in the Er:YAG group who had severe acne scars underwent 2 to 3 repeated laser treatments at 6to 12-month intervals. Fractional laser treatments were repeated every 3 weeks (NAFL) or 2 months (AFL) until scar appearance became acceptable and no additional improvement was expected, or until the patient discontinued clinic visits. Mean numbers of treatments are shown in Table 1 and Figure 1.
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There was no significant difference in mean number of treatments between the CO2 and Er:YAG groups, or between the NAFL and AFL groups. Mean number of treatment session per patient was significantly greater in the fractional laser groups compared with the resurfacing laser groups.
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Clinical improvement in all patients occurred between 3 and 8 weeks after treatment. Mean improvement score of the CO2, Er:YAG, NAFL, and AFL groups were 6.0, 5.8, 2.2, and 5.2,
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respectively (Table 1, Figure 1). There was no significant difference in mean score among the CO2, Er:YAG, and AFL groups, though a slightly higher score was seen in the CO2 group (p > 0.05). Mean improvement score of the AFL group closely approximated that of the resurfacing laser groups, indicating that the outcome of AFL was similar to that of ablative resurfacing. The NAFL group, however, showed a significantly lower mean score compared with the other 3 groups (p < 0.05). Although patients treated with the NAFL clearly had less social downtime, they were less satisfied with the treatment results. Figure 2-5 demonstrates examples of pre- and postoperative photographs in each group. Adverse effects included pain during treatment and posttreatment bleeding, oozing, erythema, 8
ACCEPTED MANUSCRIPT and pigmentation. All patients reported that treatment-associated pain was generally tolerated. Patients reported more severe pain with resurfacing lasers than with fractional lasers. Erythema and edema persisting for several days was observed in the resurfacing laser groups. Re-epithelialization occurred in all patients in less than 2 weeks. Risk of transient pigmentation was higher with resurfacing lasers
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than with fractional lasers; however, neither scarring nor pigmentary changes were seen in any patient
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(Table 2).
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Discussion
Acne is the most common skin disease. 8 Most patients with acne leave it as is or handle it in the wrong way, forming atrophic scars, which are often difficult to treat and can have devastating psychosocial effects. Acne scars can appear in various forms all over the face, and can be classified
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into 4 patterns as follows: (1) rolling depressed scars, (2) ice-pick scars or prominent craters, (3) conglomerated depressed scars, and (4) a combined pattern.
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Atrophic acne scars are dermal
depressions that result from inadequate replacement of deleted collagen fibers. The textural changes
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caused by collagen destruction and dermal atrophy are often permanent. Histologically, these scars are unique because of the relative absence of skin appendages and elastic fibers.
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The irregular
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arrangement of collagen fibers is thick in the dermis layer, with almost the same thickness as the surrounding tissue below the epidermis. Intradermal scars with irregularly arranged collagen bundles are located deeply (Figure 6a). 1 Dermabrasion has a more cutting effect on the surrounding normal skin than on the scar, and the elevation effect on the depressed scars is less than expected. With dermabrasion, depressed scars improved, but deep or ice pick scars showed no improvement, and depigmentation, whitening, and change of the skin contour with exudation occurred (Figure 6b). Chemical peeling is better, in that it has an equal peeling effect on the depressed scar and the surrounding normal skin, but its effect is limited. With chemical peeling, control of peeling depth is difficult, and complications may be 9
ACCEPTED MANUSCRIPT encountered (Figure 6c). The combination of laser resurfacing and laser punch-out gives more effective results by removing deep-seated scars, with less sacrifice of normal tissue (Figure 6d). Resurfacing lasers are one of the most effective treatment modalities for improvement of acne scars. Our previous study of acne scars treated using the ultrapulse CO2 laser reported a 72%
better than even-depth resurfacing for improvement of deep acne scars.
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excellent improvement of scar appearance, and also introduced the laser punch-out method, which is 1 9
An alternative to the CO2
laser is the Er:YAG laser, which is 12 to 18 times more efficiently absorbed by water. Both lasers are
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efficacious in treatment of acne scars, but the CO2 laser has superior results, while the Er:YAG laser is better tolerated with less associated downtime, fewer adverse events, and less postoperative recovery
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time.
More recently, treatment of atrophic acne scars has been performed using fractional laser devices (Figure 6e, 6f). 10 Clinical improvement of atrophic acne scars with AFLs and NAFLs results from collagen contraction and neocollagenesis. Our previous study demonstrated that both AFL and NAFL systems provide skin tightness through collagen production, but skin shrinkage was more
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noticeable in AFL-treated skin compared with NAFL-treated skin. 11 Significant clinical improvement has been shown when fractional photothermolysis is applied to atrophic acne scars. published studies compared the effects of an NAFL with an AFL on atrophic scars.
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2,6,12-25
Two
These studies
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concluded that clinical improvement with the AFL was equal to or greater than that with the NAFL. However, some bias would significantly affect the outcomes. Several recent review articles
7,10,20,24,26
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have shown that NAFL therapy provided limited efficacy in treatment of deep acne scars, and required multiple treatments for an appropriate clinical effect. AFL had more efficacious results in patients with moderate to severe acne scars. In addition, fewer treatment sessions are required with AFL than with NAFL.
Although conventional resurfacing lasers using either a CO2 or Er:YAG laser is the gold standard for laser resurfacing, it can be associated with an undesirable adverse event profile, including high risk of infection and dispigmentation, as well as a prolonged recovery period, compared with fractional laser treatments. Unlike resurfacing lasers, which can yield significant results after just one 10
ACCEPTED MANUSCRIPT treatment, fractional lasers require multiple treatments to achieve satisfactory outcomes. Recent studies have tried to define the optimal treatment parameters that would allow fractional lasers to approach the efficacy of conventional ablative lasers. 12,21,27-32 Well-conducted comparative studies using standard protocols are few in number, and have
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rarely included acne scars. This is the first study to compare the 4 different laser systems used to treat acne scars: resurfacing (CO2, Er:YAG) versus fractional (nonablative, ablative). Mean improvement scores showed that CO2 resurfacing lasers were the most effective in improving atrophic scars.
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However, they were associated with adverse effects and complications, including pigmentary changes and prolonged erythema. Er:YAG resurfacing lasers were as effective as CO2 resurfacing lasers, with
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shorter social downtime periods and fewer adverse effects. Active acne responds well to NAFLs, which eliminate acne with an anti-inflammatory effect, but are less clinically effective for scar improvement. A single treatment with AFLs may be less effective than resurfacing lasers, but these can be used in patients desiring minimal downtime. The present study demonstrated that 3 successive treatment sessions at 2-month intervals with AFLs provided clinical outcomes equivalent to those with
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conventional resurfacing lasers. In terms of adverse events and recovery time, our findings are comparable with those of previous studies that included various treatments for acne scars. Compared with conventional resurfacing lasers, AFL therapy improves acne scars with a shorter recovery period
procedure.
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and decreased risk of infection and pigmentation. Therefore, it is the best option for a weekend
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Comparing these four laser systems after a single session is inherently flawed, since a series of fractional laser treatments is generally needed to rival the effects of one resurfacing laser treatment. Nevertheless, we compared the effect of these lasers by dividing the mean improvement score by the mean numbers of treatments. The data showed scar depth improvement of 50–70% after one treatment session with resurfacing laser therapy. After one treatment with NAFL or AFL therapy, 5% and 20% improvement was estimated, respectively. In clinical practice, factors in choosing a treatment option include not only treatment efficacy, but also risk of adverse effects, recovery time, and pain acceptability. Despite the inconclusive nature 11
ACCEPTED MANUSCRIPT of the equivalent outcomes, several factors, including risk of adverse effects and pain involved, also should be taken into account when a therapeutic option is being considered. It is also important to note that different types of acne scars will respond differently to laser resurfacing. Of all the scar types, rolling scars have been reported to respond best, while ice-pick pitted scars respond worst, to 21,33
If pits or ice-pick scars are the predominant scar type in any individual
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fractional treatment.
patient, he/she is unlikely to be satisfied with fractional resurfacing alone. In order for ablative fractional CO2 laser resurfacing to be safer and more effective, both conventional ablative resurfacing
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and fractional laser therapy are combined to treat moderate to severe acne scars.
There were several limitations to this retrospective study. First, total number of treatment
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sessions and time interval between treatments varied among patients. Mean number of treatment sessions per patient was greater in the CO2 group compared with the Er:YAG group, though it did not reach statistical significance. There may be advantages if the number of treatments is increased because more profound clinical improvement may be noted. Second, the statistical results may be limited by the small and unequal sample size of each group. Nonparametric tests were used for data
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analysis. A prospective controlled randomized study would be required for better comparisons. The third limitation of this study is that analysis was based on assessment of clinical photographs taken prior to each treatment session, rather than at standard time intervals after each treatment. Lastly, the
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grading system is fraught with subjective bias.
Our results do not constitute a conclusive comparison of the 4 laser systems. However, it
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appears that 3 AFL treatments are as effective as a single treatment with resurfacing lasers, without a statistical difference. We recommend the Er:YAG resurfacing laser for patients who can afford to have 10–14 days of downtime, or who can tolerate the social downtime; this laser also has fewer adverse events such as erythema and postinflammatory hyperpigmentation than the CO2 laser. AFL may be used in patients desiring further treatments following laser resurfacing. It is also recommended if the laser treatment disrupts patients’ social activity. NAFLs are less effective in improvement of acne scars, but have therapeutic effects on acute inflammatory acne by reducing redness and inflammation. We believe our study could be used as an essential reference when choosing laser modalities for acne 12
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Conflict of interest statement:
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The authors have no conflicts of interest to disclose in relation to the content of this article.
Financial disclosure statement:
None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this
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manuscript.
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Funding:
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None
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Figure Legends Figure 1. Mean clinical improvement scores (*p < 0.05).
treatment (500mJ; 2 passes).
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Figure 2. (a) Before laser treatment and (b) 12 months after 2 sessions of CO2 resurfacing laser
Figure 3. (a) Before laser treatment and (b) 6 months after Er:YAG resurfacing laser treatment
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Figure 4. (a) Before laser treatment and (b) 10 months after 5 sessions of NAFL treatment (30mJ,
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Figure 5. (a) Before laser treatment and (b) 7 months after 2 sessions of AFL treatment (120mJ, 150spots/cm2; single pass).
Figure 6. (a) The epidermis of the acne scar has the same appearance and thickness as the
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surrounding tissue, but a thick collagen bundle of scars exists deep in the dermis. (b) Dermabrasion (c) Chemical peeling (d) Laser resurfacing (e) Nonablative fractional laser; NAFL (f) Ablative
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Tables Table 1. Patient demographics
Fractional
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Resurfacing Er:YAG
NAFL
AFL
10,600
2,940
1,550
10,600
17
18
11
12
Male
7
9
9
Female
10
9
No. of patients
Age, y Mean ± SD Range
24 ± 3.9 18-30
No. of treatments 1.6 ± 0.9
Range
29 ± 6.6
18-45
22-36
23-45
1.1 ± 0.3
4.0 ± 1.3
3.4 ± 0.7
1-5
2-4
11.4 ± 7.3
14.0 ± 11.8
6.4 ± 0.9
6.8 ± 1.1
6-32
6-54
6-9
6-9
5.8 ± 1.9
2.2 ± 1.3
5.2 ± 2.1
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Improvement score, mean ± SD
26.7 ± 4.2
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28.8 ± 8.2
1-3
Follow-up period, mo Mean ± SD
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2
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Wave length, nm
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CO2 ultrapulse
Laser
6.0 ± 2.0
Abbreviations: AFL, ablative fractional laser; CO2, carbon dioxide; Er:YAG, erbium-doped yttrium aluminum garnet; NAFL, nonablative fractional laser.
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Resurfacing
Fractional
CO2 ultrapulse
Er:YAG
NAFL
AFL
Pain
+++
+++
++
+
Oozing
++
++
-
5-10
4-7
1-3 months
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Epithelialization, d
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Laser
+
2-3
2-4 weeks
2-3 days
1-2 weeks
1 month
1-2 weeks
1-2 days
3-4 days
%
80%
60%
10%
20%
Degree
++++
+++
±
+
25
1-2
-
11.5
-14
-4.3
-9
Erythema
Social downtime
-43
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Late collagen contraction, %
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Immediate collagen shrinkage, %
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PIH
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1
Abbreviations: AFL, ablative fractional laser; CO2, carbon dioxide; Er:YAG, erbium-doped yttrium aluminum garnet; NAFL, nonablative fractional laser; PIH, postinflammatory hyperpigmentation.
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