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Comparison of a Fractional Bipolar Radiofrequency Device and a Fractional Erbium-Doped Glass 1,550-nm Device for the Treatment of Atrophic Acne Scars: A Randomized Split-Face Clinical Study
Article first published online: 25 NOV 2013
© 2013 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.
Volume 40, Issue 1, pages 14–21, January 2014
How to Cite
Rongsaard, N. and Rummaneethorn, P. (2014), Comparison of a Fractional Bipolar Radiofrequency Device and a Fractional Erbium-Doped Glass 1,550-nm Device for the Treatment of Atrophic Acne Scars: A Randomized Split-Face Clinical Study. Dermatologic Surgery, 40: 14–21. doi: 10.1111/dsu.12372
- Issue published online: 6 JAN 2014
- Article first published online: 25 NOV 2013
A fractional erbium-doped glass 1,550-nm and a fractional bipolar radiofrequency (RF) device are effective in the treatment of atrophic acne scars.
To compare the clinical effectiveness and side effects of fractional bipolar RF with those of fractional erbium-doped glass in atrophic acne scars treatment.
Materials and Methods
Twenty Thai subjects with atrophic acne scars received three split-face monthly treatments, one side with fractional bipolar RF and the other with fractional erbium-doped glass. Three independent physicians and patients evaluated improvement in acne scars 4 weeks after the last treatment. Side effects were also recorded after each treatment.
The study found significant improvement in acne scars after treatment with fractional bipolar RF and with a fractional erbium-doped glass device without a statistically significant difference between the two devices. The side effects of both devices were pain, transient facial erythema, and scab formation. The pain score with fractional erbium-doped glass was higher than that with fractional bipolar RF, but duration of scab shedding was shorter. One case had postinflammatory hyperpigmentation on only the side treated with fractional erbium-doped glass.
Fractional bipolar RF and fractional erbium-doped glass have similar effectiveness for the treatment of atrophic acne scars.
Acne vulgaris is a common skin disease. The prevalence of acne vulgaris is >90% in adolescents. Some acne lesions result in disfiguring scars. There are many options for the treatment of acne scars, such as chemical peeling, dermabrasion, subcision, punch excision, tissue augmentation, and laser.[2, 3] Treatment of acne scars must be individually chosen for each patient, depending on the type and severity of the lesions and the patient's expectations. Laser treatment is useful in treating acne scars. There are many types of laser treatment, including ablative laser resurfacing and nonablative laser and fractional photothermolysis (FP). Although ablative lasers using carbon dioxide and erbium-doped yttrium aluminum garnet (YAG) lasers provided significant improvement in acne scars, there are several side effects associated with this treatment such as prolonged erythema and dyspigmentation, especially in patients with darker skin. Nonablative remodeling lasers, such as the 1,064-nm neodymium-doped YAG laser, diode (1,450-nm) laser, and 585-nm pulsed dye laser, can also reduce acne scars without significant downtime. The fractional erbium-doped glass 1,550-nm laser is a kind of fractional nonablative laser that has high effectiveness in acne scar treatment,[9-11] based on the principle of FP, which creates multiple small zones of thermal injury, called microscopic treatment zones (MTZs). This technique increases the efficacy of nonablative lasers and recovery is faster and there is a lower risk of side effects than with the ablative resurfacing system. More recently, fractional bipolar radiofrequency (RF), based on the principle of “sublative rejuvenation,” which causes low epidermal disruption with high dermal remodeling, has been introduced to improve the efficacy and reduce the side effects of FP. The fractional bipolar RF device was also able to improve acne scars significantly,[12-14] although no controlled study comparing the efficacy of the fractional bipolar RF device with that of the fractional erbium-doped glass 1,550-nm device has been done. This study, therefore, was conducted to compare the clinical effectiveness and side effects of the fractional bipolar RF device with those of the fractional erbium-doped glass 1,550-nm device for the treatment of atrophic acne scars. It was a randomized split-faced clinical study.
Materials and Methods
Twenty Thai patients aged 18–55 with Fitzpatrick skin types III to V and atrophic acne scars on both cheeks were enrolled in the study. Patients signed an informed consent form for participation in the study. Exclusion criteria were pregnancy, lactation, photosensitivity, electrical implantation, immunocompromise, history of deep chemical peeling or laser resurfacing, botulinum toxin or filler injection in the previous 6 months, history of hypertrophic scars and keloids, use of isotretinoin within 6 months, allergy to anesthesia, active inflammatory skin disease or premalignant and malignant lesions in the treatment area, and history of herpes simplex or herpes zoster on the face. The Mae Fah Luang Ethical Committee, Chiang Rai, Thailand, approved the study protocol, which conformed to the ethical guidelines of the 1975 Declaration of Helsinki.
The researcher generated randomization sequence which randomly determined which side of the patient's face was to be treated using the fractional bipolar RF device (eMatrix, Syneron, Haifa, Israel) and the other with the fractional erbium-doped glass 1,550-nm device (Fraxel re:store DUAL1550/1927, Solta Medical, Hayward, CA) using random allocation software and concealing the sequence in opaque envelopes. Before each treatment, the researcher took a photograph of each patient using VISIA® Complexion Analysis System, (Canfield, Fairfield, NJ). Anesthetic cream (2.5% lidocaine/prilocaine, EMLA, APP Pharmaceuticals, Schaumburg, IL) was applied to the treatment area under occlusion for 1 hour. The researcher performed the intervention on each side of the patient's face according to the prepared randomized sequence. Three treatment sessions were done at 4-week intervals. The device used on each side of the face was the same at all three treatment sessions. The parameter of the fractional bipolar RF device with 64-electrode-pin disposable tips was Program C (53–59 mJ/pin for 2 passes). The energy settings of the fractional erbium-doped glass 1,550-nm device ranged from 30 to 50 mJ/MTZ, with treatment levels 4–5 (corresponding to 10–14% treatment coverage) for eight passes. A cooling system (Cryo 6 Skin Cooling System, Zimmer MedizinSystems, Irvine, CA) was used at the setting of 5. Patient skin response was used to set the appropriate energy for the treatment. After treatment, patients applied noncomedogenic moisturizer (Cetaphil moisturizing cream, Galderma, Biot, France) and sunscreen (Cetaphil UVA/UVB Defense SPF 50, Galderma) and washed their face with mild soap (Cetaphil Gentle Skin Cleanser, Galderma).
Clinical evaluation was done 1 month after completing the three treatment sessions. First, three masked dermatologists and patients evaluated clinical improvement of acne scars. They independently evaluated improvement in acne scars by comparing the photographs taken before and after three treatment sessions (grading scale: 0 = no improvement, 1 = <25% (mild) improvement, 2 = 25–50% (moderate) improvement, 3 = 51–75% (good) improvement, 4 = >75% (excellent) improvement). Second, improvement in facial texture was evaluated by comparing the texture scores obtained from the Complexion Analysis System before and after treatment. Texture scores indicate irregularity on the facial surface. Third, patients were asked to evaluate their satisfaction with the treatment using a grading scale (0 = dissatisfied, 1 = less satisfied, 2 = moderately satisfied, 3 = very satisfied, 4 = most satisfied). Side effects, including pain score (0, no pain to 10, the most pain), duration of facial erythema, facial dryness, duration of scab shedding, infection, ulceration, scar formation, dyspigmentation, and acneiform eruption, were record. The data were reported as means ± standard deviations. Statistical analysis was conducted using the paired samples t-test for comparison of the effectiveness and side effects of the two treatment devices. p < .05 was considered statistically significant.
Nineteen (14 with Fitzpatrick skin type III, 2 with type IV, 3 with type V) of 20 patients (12 male, 8 female) completed three treatment sessions. One man with Fitzpatrick skin type III withdrew from the study because he developed side effects in the form of prolonged dyspigmentation, which became evident after the second treatment session and negatively affected his professional life.
Mean improvement grade in acne scars of dermatologists after treatment was 2.70 ± 0.37 for the fractional bipolar RF device and 2.86 ± 0.42 for the fractional erbium-doped glass device. Mean improvement grade of patients was 2.74 ± 0.73 for the fractional bipolar RF device and 2.89 ± 0.57 for the fractional erbium-doped glass device. There was no statistically significant difference in mean acne scars improvement grade between the two devices. Clinical improvement results are shown in Figures 1 and 2.
Figure 3 presents mean texture scores before and after each treatment session. Reduction in texture score indicates improvement in facial texture. There were statistically significant (p < .001) reductions in texture scores after treatment with the fractional RF device (2.71 ± 1.92) and the fractional erbium-doped glass device (2.94 ± 1.84), although there was no statistically significant difference in mean reduction in texture scores between the two treatment devices (p = .62).
After being treated with the fractional bipolar RF device, six patients (31.6%) rated their satisfaction as moderately satisfied, 10 (52.6%) rated as very satisfied, and three (15.8%) rated as most satisfied. After being treated with the fractional erbium-doped glass device, five patients (26.3%) rated their satisfaction as moderately satisfied, 13 (68.4%) rated as very satisfied, and one (5.3%) rated as most satisfied.
Side effects of both treatment devices were pain, transient facial erythema, facial dryness, and scab formation. Mean pain scores were 5.90 ± 1.21 on the side treated using the fractional bipolar RF device, and 7.75 ± 1.37 on the side treated using the fractional erbium-doped glass device. The pain score after treatment with the fractional erbium-doped glass device was higher than with the fractional bipolar RF device (mean difference = 1.85 ± 1.30; p < .001). Duration of facial erythema was 3.10 ± 1.17 days after treatment with the fractional bipolar RF device and 2.90 ± 1.65 days after treatment with the fractional erbium-doped glass device. There was no statistically significant difference between the two devices. The duration of scab shedding was 5.00 ± 2.60 days after treatment with the fractional bipolar RF device and 3.45 ± 2.95 days with the fractional erbium-doped glass device. Duration of scab shedding treatment was longer with the fractional bipolar RF device than with the fractional erbium-doped glass device (mean difference = 1.55 ± 2.65 days; p = .01). Duration of facial dryness was 3.85 ± 3.15 days after treatment with the fractional bipolar RF device and 3.25 ± 2.71 days with the fractional erbium-doped glass device. There was no statistically significant difference between the two devices (Table 1).
|Side Effect||Treatment Method||Mean ± SD||Difference, Mean ± SD||p-Value|
|Pain score||Fractional RF||5.90 ± 1.21||–1.85 ± 1.30||<.001|
|Fractional erbium-doped glass||7.75 ± 1.37|
|Erythema, days||Fractional RF||3.10 ± 1.17||0.20 ± 1.70||.60|
|Fractional erbium-doped glass||2.90 ± 1.65|
|Scab, days||Fractional RF||5.00 ± 2.60||1.55 ± 2.65||.01|
|Fractional erbium-doped glass||3.45 ± 2.95|
|Dryness, days||Fractional RF||3.85 ± 3.15||0.60 ± 1.57||.10|
|Fractional erbium-doped glass||3.25 ± 2.71|
One case (1/20 = 5%) with skin type III had prolonged facial erythema, especially when being exposed to the sunlight, lasting more than 2 weeks and had post-inflammatory hyperpigmentation after the second treatment session with fractional erbium-doped glass device, at parameter; fluence 40 mJ/cm2, treatment level 5 (14% coverage), 8 passes. The hyperpigmentation resolved at 6 weeks after being treated with bleaching agent (combination of 4% hydroquinone, 0.01% fluocinolone acetonide, and 0.05% tretinoin; Triluma®). The other side of the face treated with the fractional bipolar RF did not have these side effects (Figure 4). However, no other side effects such as infection, ulceration, scar formation or acneiform eruption were present in any subjects.
The fractional erbium-doped glass 1,550-nm laser is a type of FP laser. In 2006, the second generation of the fractional erbium-doped glass 1,550-nm was launched. The energy can be adjusted from 4 to 100 mJ/MTZ. With the highest pulse energy of 100 mJ/MTZ, mean depth of MTZ was 1,408 ± 53 μm. With the pulse energy of 30, 40, and 50 mJ, which were used in this study, mean depth of MTZ was 890 ± 65 μm, 1,007 ± 75 μm, and 1,079 ± 97 μm, respectively. After the healing process, the MTZ was replaced with new collagen.
Radiofrequency is nonionizing electromagnetic radiation with a frequency range between 3 kHz and 300 GHz. With the fractional bipolar RF device, the RF current flows through the skin between the electrode-pin rows. It generates fractional deep dermal heating in the region of the electrode matrix to induce skin injury and then elicits a wound healing response, stimulating the remodeling of dermal collagen. It generates RF current flows between the multi-electrode pins, which causes volumetric dermal heating, followed by stimulation of the remodeling of dermal collagen in healing process. In this study, 64-pin tips, which can deliver RF at 5% epidermal coverage, were used. The depth of RF effect was approximately half of the distance between the electrode pins. Therefore, the 64 electrode pins on a 12- by 12-mm tip, with a distance between pins of 1.5 mm, could generate the thermal effect of approximately 750-μm depths.
Previous studies showed that fractional erbium-doped glass 1,550-nm and fractional bipolar RF devices were effective for skin rejuvenation and treatment of acne scars.
Ong and Bashir reviewed the literature about the use of the FP laser for acne scar treatments. Twenty-six studies (13 ablative and 13 nonablative FP), were included in this review. For ablative FP, improvement ranged between 26% and 83%, whereas for nonablative FP, improvement ranged between 26% and 50%. The side effects included facial erythema lasting 3–14 days with ablative FP laser and 1–3 days with nonablative FP laser, postinflammatory hyperpigmentation (PIH), which occurred in a higher proportion of patients (up to 92.3%) who underwent ablative FP than those who underwent nonablative FP (up to 13%). The maximum duration of PIH in ablative FP was up to 6 months, whereas in nonablative FP, it lasted for up to 1 week. The pain score (scale 1–10) ranged from 5.9 to 8.10 with ablative FP and from 3.90 to 5.66 with nonablative FP.
In 2010, Ramesh and colleagues evaluated the efficacy of a matrix-tunable RF device in 30 patients with acne scars. Two independent observers evaluated improvement in acne scars on an visual analog scale (VAS) 2 and 6 months after completing four treatments. VAS improvement in acne scars ranged from 10% to 50% at the end of 2 months and 20% to 70% at the end of 6 months. Side effects were transient facial erythema and edema for 2–3 days. No postinflammatory pigmentary changes were reported in any of the patients.
As in previous studies, this study also found significant improvement in acne scars and skin texture after treatment with the fractional bipolar RF device and the fractional erbium-doped glass device. The present study found that there was no statistically significant difference between the devices in mean acne scar improvement grade evaluated by independent dermatologists (p = .26) and patients (p = .33), mean satisfaction (p = .75), or facial texture improvement evaluated using VISIA® Complexion Analysis System (p = .62), although the quantitative measurement validity of skin texture using VISIA® Complexion Analysis System has not been established in any previous studies.
Because this study was a split-face study, the side effects of the two devices could be compared without any influence of various characteristics of the patients, including skin type and post-treatment care. There were statistically significant differences in pain scores and duration of scab shedding after treatment with the fractional bipolar RF device and the fractional erbium-doped glass device. The pain score with the fractional erbium-doped glass device was higher than of the fractional bipolar RF device, but the duration of scab shedding after using the fractional erbium-doped glass device was shorter than with the fractional bipolar RF device.
In the present study, one case (5%) with skin type III had prolonged erythema and PIH after the second treatment session with the fractional erbium-doped glass device, at a fluence of 40 mJ/cm2, treatment level 5 (14% coverage), and eight passes, although the side of the face treated with fractional bipolar RF device did not have such side effect. Further study is needed to confirm whether the fractional bipolar RF has less risk of PIH than FP.
The consensus recommendations on the use of a fractional erbium-doped glass laser suggest that treatment settings for acne scars should be between 30–70 mJ. The present study used the parameter of 30–50 mJ; further study at a higher energy setting is required.
The present study has a limitation in that the comparison of effectiveness with atrophic acne scar subtypes (ice-pick, boxcar, rolling) was not done because most participants had mixed types of acne scars. For rolling scars, subcision is a recommended treatment method. Further research is therefore needed to evaluate the effectiveness of combination treatment of subcision and subablative fractional bipolar RF.
Moreover, further 3- and 6-month follow-up studies are needed to investigate the sustainability of the acne scar treatment using the two devices. Additional treatment sessions are required to explore an increase in improvement of such treatment.
In conclusion, a fractional erbium-doped glass 1,550-nm device and the fractional bipolar RF device are safe and effective treatment modalities for the treatment of atrophic acne scars in patients with Fitzpatrick skin types III to V. Most patients were very satisfied with the result of the treatment. The effectiveness of both devices in the treatment of atrophic acne scars was similar. Side effects from the treatment were mild and transient.
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