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Table of Contents
Year : 2019  |  Volume : 16  |  Issue : 1  |  Page : 37-42

Microneedling versus fractional CO2 laser in the treatment of atrophic postburn scars

1 Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt
2 Department of Biochemistry, Faculty of Medicine, Cairo University, Cairo, Egypt
3 Department of Pathology, National Research Center, Cairo, Egypt

Date of Submission30-Jan-2018
Date of Acceptance14-Nov-2018
Date of Web Publication09-May-2019

Correspondence Address:
Heba M Abdel Raheem
52, Mohamed Mandour St, Nasr City, Zip Code 11759, Cairo
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/JEWD.JEWD_1_19

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Background Microneedling is an evolving approach in the treatment of postburn scars based on the principle of collagen induction and neovascularization.
Objective To evaluate and compare the clinical and histopathological outcome of microneedling versus ablative fractional CO2 laser targeting atrophic postburn scars.
Patients and methods Twenty-five patients with atrophic postburn scars were included in this study. Each patient received four treatment sessions of both microneedling and fractional CO2 laser with 4-week interval. Histopathological and histochemical evaluations of collagen and elastic fibers were done. Quantitative morphometric studies were also performed.
Results A significant increase in collagen deposition was detected after fractional CO2 laser therapy. A significant increase in elastic fiber deposition was detected after both laser therapy and microneedling with fractional CO2 laser showing more significant results than microneedling.
Conclusion Ablative fractional CO2 laser is more effective than microneedling in the treatment of atrophic postburn scars; however, microneedling did show a significant increase in elastic fiber deposition and thus can be a promising therapeutic approach when combined with other treatment modalities.

Keywords: fractional carbon dioxide laser, microneedling, postburn scar

How to cite this article:
Zayed AA, Mashaly HM, Abdel Raheem HM, El-Nabarawy E, El-Hawary MS, Shaker OG, Elnemer RS, Aldhahebi WE. Microneedling versus fractional CO2 laser in the treatment of atrophic postburn scars. J Egypt Womens Dermatol Soc 2019;16:37-42

How to cite this URL:
Zayed AA, Mashaly HM, Abdel Raheem HM, El-Nabarawy E, El-Hawary MS, Shaker OG, Elnemer RS, Aldhahebi WE. Microneedling versus fractional CO2 laser in the treatment of atrophic postburn scars. J Egypt Womens Dermatol Soc [serial online] 2019 [cited 2022 Dec 3];16:37-42. Available from: http://www.jewd.eg.net//text.asp?2019/16/1/37/257859

  Introduction Top

Atrophic scars are the most common type of burn scars in which the base of the scar is located below the level of surrounding tissues. The overlying skin of atrophic scars is thin and flaccid. Sometimes the melanocytes are damaged causing the scar to look white. The characteristic look of these scars is caused by connective tissue loss, notably collagen and elastin proteins, which form the skin frame [1].

Fractional ablative CO2 laser is used for the treatment of burn scars resulting in improvement of the color and contracture of the scar, as well as the psychological well-being of patients [2],[3],[4]. This mode of treatment also results in marked improvement in collagen architecture [5],[6].

An expanding modality in the treatment of atrophic scars is microneedling. Microneedling is based on the principle of neocollagenesis and neovascularization that result from the release of growth factors following piercing of the stratum corneum with needles. These growth factors are believed to cause the beneficial effects of the procedure in the treatment of scars [7]. Microneedling carries the advantage of being less invasive than fractional CO2 laser, with very minimal postoperative downtime [8]. It can be safely done on darker skin types without fear of postoperative hyperpigmentation [9].

Our aim in this study was to evaluate and compare the results of microneedling and fractional CO2 laser in the treatment of atrophic burn scars, both clinically and histopathologically, by assessment of collagen and elastin fiber deposition.

  Patients and methods Top

This study was a ‘within-patient’ comparative study. A total of 25 patients with atrophic postburn scars were consecutively recruited in this study. Their skin type ranged between III and IV Fitzpatrick skin type. They were recruited from the dermatology outpatient clinic at the Faculty of Medicine, Cairo University. The study was approved by the Dermatology Research Ethics Committee, and an informed written consent was obtained from every participant before enrollment in this study. Exclusion criteria included patients with bleeding disorders; active skin infections, for example, herpes; history of keloid formation; and the use of isotretinoin within 6 months before the procedure.

All patients were subjected to complete history taking including the duration of the scar and previous treatment trials. Clinical examination was done to determine the Vancouver Scar Scale (VSS), which assesses four scar variables: vascularity, pigmentation, pliability, and height or thickness with a total score between 0 and 13 points [10]. All patients were photographed using Sony Cyber shot digital still camera (DSC-W300; Sony, Tokyo, Japan) before therapy and after each treatment session. In each patient, the atrophic postburn scar area was outlined and divided into three areas: one area was treated by ablative fractional CO2 laser, the second area was treated by microneedling, and the third area was left untreated to serve as a control.

Each patient received four treatment sessions with 4-week interval. Patients were assessed in between the sessions for the emergence of any adverse effects including prolonged erythema (lasting >3 days), pain (graded as mild, moderate, and severe), swelling, infection, hyperpigmentation, or hypopigmentation.

Treatment procedure

Topical anesthesia [a compound lidocaine 25% and prilocaine 25% (Pridocaine; Global Napi Pharmaceuticals, Egypt)] was applied under occlusion 60 min before the procedure and wiped off just before the treatment. Ablative fractional CO2 laser (SmartXide DOT; DEKA, Calenzano, Italy) was used on the first area with the following parameters: power 25 W, dwell time 800 μs, spacing 600 μm, and stack 3. Microneedling device (Dermapen; IP Holdings LLC, Delaware, Utah, USA) was used on the second area of the scar with a needle size 1.5 mm and 12 needle tips. Stamping technique was applied. The session was done until enough bleeding was seen.

Histopathological and histochemical evaluation

Three 6-mm punch skin biopsies were taken from each patient: one was taken from the scar area before treatment, one immediately after last treatment session by ablative fractional CO2 laser, and one immediately after last treatment session by microneedling. Each biopsy was divided into two halves for histopathological and histochemical analysis. The biopsies were fixed in 10% neutral buffered formalin and then embedded in paraffin blocks. Sections were prepared for routine staining by hematoxylin and eosin [11]. Other sections were prepared for histochemical staining of collagen fibers using Masson’s trichrome stain and elastic fibers using orcein stain [12].

Hematoxylin and eosin staining technique

Paraffin sections were de-waxed and hydrated. They were stained in Mayer’s haemalum for 1–15 min. Running tap water was used to wash the sections for 2–3 min or until the sections turned blue. Sections were immersed in eosin for 30 s. Running tap water was used again to wash the sections for 30 s. Dehydration of the sections was done using ascending concentrations of ethanol (70, 95, and 100%) for 5 min each. Sections were then cleared in xylene and mounted in Canada balsam.

Masson’s trichrome staining technique for the demonstration of collagen fibers

Sections were deparafinized, and tap water was used to wash them. Nuclei were stained by the Celestine blue hematoxylin method and differentiated in 1% acid alcohol. Sections were washed in tap water and stained in acid fuchsin for 5 min, and then rinsed in distilled water. Phosphomolybdic acid was used to treat the sections for 5 min, and then they were stained with methyl blue for 2–5 min and rinsed in distilled water. Sections were treated with 1% acetic acid for 2 min and dehydrated through alcohol. Sections were cleared in xylene and mounted in Canada balsam.

Orcein staining technique for the demonstration of elastin fibers

Paraffin sections were de-waxed and hydrated. Potassium permanganate solution was added for 10 min and then washed in water. After that, 5% oxalic acid was added until colorless. Sections were washed in tap water and then rinsed in distilled water. Thereafter, 0.5% Periodic acid was added for 5 min. Sections were washed in tap water and then rinsed in distilled water. Orcein solution was added and microwaved at low power for 30–45 s, and then allowed to stand for 30 min. Sections were then rinsed in 70% alcohol and dehydrated.

All sections were examined using a Zeiss, Primo star light microscope (Zeiss, Oberkochen, Germany). The microscope has an integrated camera by which photomicrographs depicting the various histopathological and histochemical findings were obtained.

Image analysis (quantitative morphometric study)

Image analysis was done using the Leica Qwin 500 Image Analyzer (Leica Imaging Systems Ltd, Cambridge, UK). It consists of Leica DM-LB microscope with JVC color video camera attached to a computer system (Leica Q 500IW). Morphometric analysis was carried out on both Masson-stained and orcein-stained slides. Adjustment of illumination was checked for on the video monitor. Morphometric measurements were performed on real-time image from the microscope that was visualized on the video monitor. Then the area stained with Masson/orcein was measured in five fields using magnification ×400. Results automatically appeared on the monitor in the form of mean±SD [13].

Statistical methods

Data were statistically described in terms of mean±±SD, and range, or frequencies (number of cases) and percentages when appropriate. Comparison between the study groups was done using paired t-test in normally distributed data and Wilcoxon signed rank test for paired (matched) samples when not normally distributed. P values less than 0.05 were considered statistically significant. All statistical calculations were done using computer program (statistical package for the social science SPSS Inc., Chicago, Illinois, USA) release 15 for Microsoft Windows (2006).

  Results Top

A total of 25 patients were enrolled in this study; five patients dropped out after the second treatment session owing to inconvenience caused by long distance travelled to receive the sessions. The 20 patients who completed the treatment sessions were 15 (75%) females and five (25%) males. Their ages ranged from 10 to 45 years (mean 20.60±7.989).

Regarding clinical evaluation, the mean VSS for the scars before treatment was 3.90±1.252. After microneedling, the mean VSS was 3.90±1.252 (P=0.083), whereas after fractional CO2 laser the mean VSS was 3.75±1.372 (P=0.083), with no statistical significance with either of the two modalities ([Figure 1]). The mean VSS following fractional CO2 laser was slightly lower than that following microneedling, but with no statistical significance (P=0.083).
Figure 1 Vancouver Scar Scale (VSS) comparison between microneedling and ablative fractional CO2 laser before and after treatment: (a) VSS before treatment, (b) VSS after microneedling, (c) VSS after fractional CO2 laser.

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Regarding morphometric measurements, they showed a significant increase in collagen fibers following fractional CO2 laser (P=0.011; [Table 1] and [Figure 2]) and a significant increase in elastic fibers following both microneedling and fractional CO2 laser (P=0.009 and <0.001 respectively; [Table 2] and [Figure 3]). When comparing the increase in elastic fibers following both treatments, fractional CO2 laser showed a more significant increase than microneedling (P<0.001).
Table 1 Comparison of the mean area percent of collagen (Masson’s trichrome) before and after treatment with microneedling and fractional CO2 laser

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Figure 2 Photomicrograph representing Masson staining for collagen fibers. (a) Showing pale collagen fibers (arrows), appears blue by Masson stain in pretreatment specimen (mean stain area percentage 39.6±5.2) (×200, MT). (b) Showing increased collagen fibers (arrows), appears blue by Masson stain, after ablative fractional CO2 laser (mean stain area percentage 51.01±2.3) (×200, MT). (c) Showing increased collagen fibers (arrows), appears blue by the Masson stain, after microneedling (mean stain area percentage 46.1±4) (×200, MT).

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Table 2 Comparison of the mean area percent of elastic fibers (orcein stain) before and after treatment with microneedling and fractional CO2 laser

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Figure 3 Photomicrograph representing orcein staining for elastic fibers. (a) Showing elastic tissue deposition (arrows) in pretreatment specimen, stained by orcein as black fibers (mean±SD=18.56±0.8%) (×400, orcein). (b) Showing increased elastic tissue deposition (arrows) after ablative fractional CO2 laser, stained by orcein as black fibers (mean±SD=40.70±3.7%) (×400, orcein). (c) Showing increased elastic tissue deposition (arrows) after microneedling, stained by orcein as black fibers (mean±SD=26.80±3.2%) (×400, orcein).

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  Discussion Top

Atrophic burn scars result from destruction of the collagen component of the dermis leading to depression in the skin surface [14]. Several modalities are available for treating atrophic scars including laser resurfacing, dermabrasion, and chemical peels [15]. They all target the abnormal collagen deposition and aim at normalizing the skin texture. Another evolving treatment modality for atrophic scars is microneedling. Microneedling causes collagen induction by controlled wounding [16]. Capillaries and fibroblasts migrate into the scar tissue, and synthesized collagen fibers (type III) integrate into the skin matrix [17]. Microneedling has the advantage of being less invasive than fractional lasers with less downtime [8]. It also has less incidence of postprocedure hyperpigmentation [9].

We aimed in this study to evaluate the effectiveness of microneedling in treating atrophic postburn scars and compare the results with those of fractional CO2 laser.

Clinical evaluation of the cases in the current study was done using the VSS. The choice of VSS was based on previous studies done in the 90’s, which recommended VSS in scoring of scars as it provides descriptive terminology for assessment of treatment results [10],[18]. In this study, no significant change of VSS was noticed, neither after microneedling nor after ablative fractional CO2 laser. Although on comparing the scores, the extent of improvement after laser treatment (especially pliability) seemed better than that after microneedling. A German study reported a significant improvement of VSS after 1 year of treatment of atrophic scars using microneedling [19]. The discrepancy between the two results can be explained by the relatively short follow-up period of our patients (4 months), whereas the complete results of microneedling are visible after 32 weeks from the last treatment session [20]. Follow-up of the cases for a longer period of time might possibly show better VSS results.

Case reports using ablative fractional CO2 laser in the treatment of burn scars reported improvement of texture and the scars becoming more mobile and stretchable [21]. On a more comparable pattern of improvement to our study, Weiss et al. [22] treated atrophic scars using ablative fractional CO2 laser that was followed by subjective clinical improvement; however, the extent of improvement was not found to be statistically significant.

Morphometric analysis of the mean area percent of collagen using Masson trichrome stain in the current study showed a statistically significant increase in the amount of collagen deposition following fractional CO2 laser. Fractional erbium: glass NFL 1540 laser was used in 2014 by Taudorf et al. [23] to treat atrophic burn scars. Following therapy, collagen structure changed from thick hyalinized bundles into uniform interwoven fibers with higher vascularity. Walia and Alster [24] also detected positive histopathological evidence of collagen deposition following CO2 laser resurfacing in the treatment of atrophic scars.

Microneedling was also reported to induce considerable increase in collagen deposition in atrophic burn scars 6 months following the sessions [19],[25]. Improvement of collagen following microneedling in the current study was not able to match the criteria mentioned in the latter studies, possibly owing to a shorter follow-up period, and may be owing to the fact that patients in our study were not prepared with vitamins A and C before treatment, which are known to increase collagen production.

Morphometric analysis of orcein-stained sections was used in this study and detected a significant increase in the mean area percent of elastic fibers following both microneedling and fractional CO2 laser, with more deposition following laser. Very few studies have assessed elastic fiber deposition in laser treatment of atrophic scars, including Aust et al. [26], who reported an increase in elastic tissue deposition in atrophic scars 6 and 12 months following therapy.

  Conclusion Top

Ablative fractional CO2 laser is able to achieve a more abundant collagen and elastic tissue deposition than microneedling, possibly owing to its more penetrative nature. Longer periods of follow-up of patients might be able to reveal a delayed, yet more visible and palpable, clinical response. Microneedling also showed a significant increase in elastic fiber deposition and can be a promising treatment modality for atrophic postburn scars especially when combined with other therapeutic approaches such as ablative fractional CO2 laser. Limitations of this study include a short follow-up period. We should continue to identify new approaches and management strategies for burn scars, with more studies evaluating the response using both modalities combined. The best results are likely to be achieved through multispecialty collaboration, innovative technology, and a combination of therapeutic modalities.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]

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