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| ORIGINAL ARTICLE |
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| Year : 2014 | Volume
: 34
| Issue : 1 | Page : 74-80 |
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Assessment of fractional CO 2 laser in stable scars
Abdel Aziz I El Taweel, Sherine H Abd El-Rahman
Department of Dermatology and Andrology, Faculty of Medicine, Benha University, Qalubiya, Egypt
| Date of Submission | 17-Sep-2013 |
| Date of Acceptance | 17-Mar-2014 |
| Date of Web Publication | 24-Jul-2014 |
Correspondence Address:
Sherine H Abd El-Rahman
MD, Department of Dermatology and Andrology, Faculty of Medicine, Benha University, Qalubiya
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/1110-6530.137317
Background
A variety of modalities have been used and, depending on the scar type, treatment may be invasive and/or conservative.
Objective
The aim of this study is to assess the safety and efficacy of treating stable nonhypertrophic scars using a fractional carbon dioxide (CO 2 ) laser.
Patients and methods
This is a prospective study of 25 patients (skin types III-IV, aged 6-37 years) with stable nonhypertrophic scars who underwent at least three sessions with a fractional CO 2 laser at 1-month interval. Side effects as well as improvements in texture, atrophy, and overall satisfaction with appearance were graded on a quartile scale by the patients and investigators after each treatment and 4 weeks after the final treatment. Before-after scores were compared using the Student t-test, with significance assigned to P values less than 0.05.
Results
All patients showed clinical improvement. There was no significant difference between the assessment of the investigator and the two blinded dermatologists. In terms of patient satisfaction, 32% of patients were not satisfied to slightly satisfied, whereas 68% were satisfied and 20% were very satisfied to extremely satisfied. Side effects were minimal and transient.
Conclusion
Fractional CO 2 laser treatment represents a safe, well-tolerated, effective, and promising treatment modality for nonhypertrophic traumatic and postinflammatory scars, with minimal downtime and fewer side effects. Keywords: Acne scars, fractional CO 2 laser, post-traumatic scars
How to cite this article:
El Taweel AI, Abd El-Rahman SH. Assessment of fractional CO 2 laser in stable scars. Egypt J Dermatol Venerol 2014;34:74-80 |
| Introduction | |  |
Cutaneous scarring is often one of the major patient-related concerns [1]. Surgery, burns, wounds, and inflammatory processes can lead to the development of a variety of scars. Scars can be hypertrophic, keloid, atrophic, and acne scars [2]. Once the scar has formed, it undergoes several distinct macroscopic and microscopic changes during the maturation process and is complete on average after 1 year; thus, a scar is considered 'stable' after 1 year [3].
Different treatments are utilized for each scar type including pressure therapy, silicone gel, intralesional or topical corticosteroids, radiation, and interferon [4]. These therapies have high failure and recurrence rates, as well as significant side effects [5]. For these reasons, alternative treatment options that provide improved results with less morbidity would be highly beneficial [6].
Laser therapy for hypertrophic scars has only achieved variable success in the past using the neodymium : yttrium aluminum garnet (Nd : YAG) (1064 nm) and carbon dioxide )CO 2 ) lasers [7]. Further developments in laser technology have led to nonablative and ablative fractional devices that improve scar appearance and are better tolerated than ablative CO 2 and Er : YAG [2].
In contrast to traditional laser techniques, which provide laser exposure to the entire skin surface, fractional photothermolysis (FP) creates a pattern of microscopically small, three-dimensional treatment zones [microscopic-sized thermal injury zones (MTZs)] while leaving the skin surrounding these MTZs considerably undamaged. One of the key concepts of FP is that the individual damaged tissue regions (MTZs) are so small that the damaged or destroyed tissue is rapidly repaired without any significant fibrosis. The close proximity of surrounding viable tissue facilitates wound healing [8].
The aim of this study is to assess the safety and efficacy of treating stable nonhypertrophic scars using a fractional CO 2 laser.
| Patients and methods | | |
This study was carried out on 25 patients with 28 nonhypertrophic stable scars, nine females and 16 males (skin types III-IV, aged 6-37 years). All patients were informed about the nature and the details of the procedure and signed a written informed consent that was approved by the Ethics Committee of Human Research, Benha University.
Inclusion criteria included linear and nonlinear atrophic, slightly elevated, and/or erythematous scars with no signs of keloid formation, with at least a 1-year evolution, located on the face, neck, trunk, or limbs. Exclusion criteria included tendency to produce hypertrophic scars or keloids, bleeding tendency, photosensitivity, pregnancy or lactation, active local or systemic infection, and the use of oral retinoid drugs within the past 6 months.
Before any procedure, the scars were cleansed of sebum and debris (including dirt, makeup, and powder) using a mild cleanser and 70% alcohol. A thick layer of EMLA 5% cream (lidocaine 2.5% and prilocaine 2.5%; Astrazeneca, UK) was then applied to the treatment site for 90 min. Just before the procedure, the cream was removed with dry gauze and the treatment site was once more cleaned with an antiseptic solution to include a 2 cm perimeter of untreated skin. Both the patients and the operators used eye goggles during all sessions.
Treatment was then applied to the lesion and 2 mm of the bordering unaffected skin using a 10 600 nm fractional CO 2 laser (DYM-810 CO 2 A001; Beijing DYM Laser Technology Co. Ltd, China (Mainland)) with energy settings range of 25-35 mJ/MTZ, spot size 300 μm/MTZ, pulse duration 0.2-2 ms, and MTZ density 150-200 MTZ/cm 2 . Treatment was applied in multiple passes using both stamping and rolling techniques [9].
The 'stamping' technique is performed by forming a preset pattern of multiple MTZs on a skin region within a well-defined exposure area of the fixed handpiece and then moving the handpiece to another skin region and repeating this until the entire treatment area is covered. The density of MTZs at the end of a treatment session depends on the preset density within the exposure area of the handpiece and the number of passes performed over each skin region [10]. The density preset within the exposure area of the handpiece of our device was 150-200 MTZ/cm 2 .
In contrast, the 'rolling' technique is performed by continuously rolling the handpiece across the entire treatment area. It is also referred as the 'brushing' technique because the movements of the operator are similar to those of a person using a paint brush. As the velocity of the handpiece relative to the skin varies during treatment, the delivery rate is adjusted automatically to maintain a defined, preset MTZ density per pass. The total density of MTZs at the end of a treatment session can be estimated as the density of MTZs per pass multiplied by the number of passes performed [10]. The number of passes depends on the treatment area and type of the scar.
Cooling using ice-packs was performed immediately after the procedure to reduce pain.
Post-treatment edema and redness usually disappears within a few hours to a few days and then settled in a few hours to a few days. Use of sunscreens (SPF50), avoidance of sun, and use of a moisturizer were started soon after the procedure and used daily. A mild topical steroid was prescribed if erythema and edema persisted. Postoperative topical antibiotics were usually not necessary. Avoidance of rubbing and scratching was advised. The patients were advised to refrain from premature peeling of the epidermal debris 'the crust' (i.e. scrubbing or picking) for more natural-looking results.
Patients were treated in at least three sessions with a fractional CO 2 laser at a 1-month interval. All patients were followed up after every session and for at least 4 weeks after the last treatment.
Post-treatment erythema and edema as well as improvements in texture, atrophy, and overall appearance were graded by the investigator on a quartile scale (poor, ≤25% = minimal to no improvement; fair, 26-50% = moderate improvement; good, 51-75% = marked improvement; and excellent, >75% = near-total improvement). Two blinded dermatologists assessed the treatment response by comparing pretreatment and post-treatment clinical images using the same quartile grading scale [11].
A subjective assessment was also performed by the patients in terms of their overall satisfaction with appearance using a five-point scale (grade 0, no improvement = dissatisfied; grade 1, 1-25% = slightly satisfied; grade 2, 26-50% = satisfied; grade 3, 51-75% = very satisfied; grade 4, 76-100% improvement = extremely satisfied). Patients were also asked to grade pain during the procedure on a four-point scale (0 = no pain; 1 = mild pain; 2 = moderate pain; and 3 = severe pain).
Statistical analysis
Results were analyzed using the SPSS computer software version 18.0 (Statistical Package for Social Sciences; SPSS Inc., Chicago, Illinois, USA) to compensate for the lack of objective scales in evaluation of the results of scar treatment. The t-test was used to test the significance of the difference between two independent sample means. The F-test was used to compare the means of more than two groups simultaneously. The Pearson correlation was used to show the linear relationship between two variables. For all tests used, a difference with a 'P' value less than 0.05 was considered statistically significant and a 'P' value less than 0.01 was considered highly statistically significant; otherwise, it was insignificant.
| Results | | |
This study was carried out on 25 patients [skin type III-IV, aged 6-37 years; there were nine (36%) females and 16 (64%) males] with 28 scars. The mean duration of scars was 4.82 ± 3.26 years, range 1-11 years.
[Table 1] shows that the most common cause of scarring was post-traumatic scars, which were present in 24 cases (87.72%). In terms of scars' location, 16 (57.15%) were on the cheeks, five (17.86%) on the forehead, one (3.57%) on the nose, three (10.71%) periorbital and above the eyebrows, and the remaining three scars were located evenly on the neck (3.57%), arm (3.57%), and thigh (3.57%). In terms of the scars' texture, 25 (89.29%) were depressed and the remaining three (10.71%) were slightly raised. In terms of the color of the scars, 14 scars (50%) were white, 10 scars (35.72%) were red, and the remaining four were either skin or brown colored. Taking into consideration that acne scars were considered as depressed scars with normal skin color. | Table 1: Statistical distribution of the cause, site, texture, and color of the scars studied
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In terms of shape, 18 scars were linear (64.3%), whereas 10 scars were nonlinear (35.7%). All patients underwent at least three sessions of treatment at 1-month interval. All patients tolerated the procedure with topical anesthesia (EMLA) for 90 min before the procedure with varying degrees of pain. Most of the patients (76%) had mild pain (grade 1), whereas three patients (12%) reported severe pain (grade 3). All patients reported that discomfort ceased upon removal of light.
All patients showed some sort of clinical improvement according to the assessment of the investigator and the two blinded dermatologists. More than half of the scars (53.57%) showed good improvement (grade 2) according to the assessment of the investigator and the first blinded dermatologist, whereas the second blinded dermatologist reported good improvement in only 46.43% of the scars (Chart 1). [Additional file 1]
[Table 2],[Table 3],[Table 4] and [Table 5] show the statistical correlation between the evaluation of improvement (as assessed by the investigator and the two double-blinded dermatologists) and age and sex of the patients, and duration and texture of scars. A statistical correlation was found between the assessment of the second blinded dermatologist and the age of the patients. Clinical improvement (according to the evaluation of the second blinded dermatologist) was better with younger age [Table 2]. Otherwise, there was no statistical correlation with sex of the patient [Table 3], texture [Table 4], duration [Table 2], or shape of the scar [Table 5]. | Table 2: Statistical correlation between evaluation of the results (as assessed by the investigator and the two double-blinded dermatologists) and both the age of patients and the duration of scars
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 | Table 3: Statistical correlation between evaluation of the results (as assessed by the investigator and the two double-blinded dermatologists) and sex of the patients
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 | Table 4: Statistical correlation between evaluation of the results (as assessed by the investigator and the two double-blinded dermatologists) and texture of scars
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 | Table 5: Statistical correlation between evaluation of the results (as assessed by the investigator and the two double-blinded dermatologists) and shape of scars
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[Chart 2] [Additional file 2] shows the degree of patient satisfaction after the completion of at least three sessions of treatment. Two patients with two scars (8%) were not satisfied, versus 17 patients with 20 scars (68%), who were satisfied to extremely satisfied. A highly statistically significant difference (P < 0.01) was found between physicians' evaluation (as assessed by the investigator and the two double-blinded dermatologists) and patient satisfaction [Table 6].
Post-treatment side effects were mild to moderate and transient, resolving rapidly within the study period. All patients (100%) had transient erythema and edema, which usually lasted for 1-4 days (mean 2.69 days) after each session, with a statistically significant difference (P < 0.05). At the same time, all of them (100%) developed crust for 3-8 days (mean 4.63 days), with a highly significant statistical difference (P < 0.01). However, only three patients (12%) experienced transient hyperpigmentation, which was easily controlled by the use of bleaching agents (Chart 3) [Additional file 3]. | Table 6: Statistical correlation between evaluation of the results (as assessed by the investigator and the two double-blinded dermatologists) and patient satisfaction
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[Figure 1],[Figure 2],[Figure 3],[Figure 4],[Figure 5] and [Figure 6] show the different types of scars before and after treatment.
| Discussion | | |
Fractional resurfacing is a novel variation on the theory of selective photothermolysis, wherein microscopic treatment zones of controlled width, depth, and densities are created. These controlled zones of thermal heating and tissue damage are surrounded by spared areas of viable epidermis and dermis that allow for rapid repair of the microscopic treatment zones [10].
Scars are usually classified as atrophic scars, hypertrophic scars, and keloids. This classification mainly made on the basis of the morphology as well as the natural behavior of the scars. However, in this study, we have used the term nonhypertrophic scars to encompass both atrophic (depressed) scars and flat scars, which are literally flat or protrude minimally above the level of the adjacent normal skin. This classification system is based not on the natural behavior of scars, but on the responses of scars to treatments [12].
In the current study, 25 patients (28 scars) were subjected to fractional laser therapy using a fractional CO 2 laser system; there were more males (64%) than females (36%). Statistical analysis of our results showed no statistical correlation between clinical improvement and the sex of the patients. This was in agreement with Sobhy et al. [13], who found no statistical difference in the results between both sexes after treatment of different types of scars.
Eighteen patients (72%) were of skin color III and the remaining seven patients (28%) were of skin color IV. This was in agreement with Goel et al. [14], who confirmed the suitability of fractional resurfacing for dark skin (skin type IV). In addition, Ciocon et al. [15] also reported that the side-effect profile and clinical effect were shown to be similar between different skin phototypes, and recommended the use of fractional skin resurfacing in patients with darker skin phototypes, for whom, in the past, less aggressive treatment approaches had to be used. However, Tannous [16] reported that fair-skinned patients are ideal candidates for fractional resurfacing.
There was a statistically negative correlation (P < 0.05) between clinical improvement according to the second blinded dermatologist and age as improvement was slightly better in younger patients, in agreement with Lee [12], who found a significant difference between prepubertal patients (<15 years) and postpubertal patients (≥ 15 years) in Asians; he suggested hormonal activities to be a possible cause for this. However, Gold [17] also found no statistical difference in the clinical results with age after treating scars with a fractional CO 2 laser.
In terms of scars' color, 10 scars (35.71%) were red, 14 (50%) were white, and only two (7.14%) were brown in color. Burn scar and acne scars were skin colored.
In this work, no statistically significant difference (P > 0.05) was found in the clinical improvement between depressed (89.29%) and slightly elevated scars (10.71%), and this was also observed by Nagat et al. [13].
Eight percent of the patients had no to mild pain during the procedure and the same result was also reported by Fisher and Geronemus [18].
In the current study, both rolling and stamping techniques were used interchangeably, with a preference for the rolling technique in larger scars. This was supported by Manstein and Laubach [10], who reported that the 'rolling' technique can facilitate treatment of larger areas, whereas the 'stamping' technique can facilitate the precise treatment of smaller areas, in particular, areas with an irregular surface profile. This was confirmed by Hantash and Mahmood [19] as they observed that the rolling method allows deposition of MTZs in random patterns through a continuous beam, creating a more blended appearance after treatment.
Even though split face [20] or split scar [21] are considered one of the best ways of evaluating effectiveness of laser devices in scar treatments, only in rare cases are the scars symmetrical and big enough for one part of the scar to serve a control group as the case in this work, we had 18 (64.3%) linear scars and 10 (35.7%) non linear scars, thus it was impossible to employ the split scar technique.
Both the investigator and the two blinded dermatologists noted variable aesthetic improvements. According to the investigator's assessment of scar texture and color, 21.42% of scars showed excellent improvement and 53.57% showed good improvement. However, Weiss et al. [22] found that 16% of the scars showed excellent improvement and 73% showed good improvement.
In the current study, only one burn scar was included. There was an overall improvement in the appearance of the scar according to the investigator and the assessment of the blinded dermatologists. Waibel and Beer [9] presented a case report of the efficacy of FP for burn scars with postulated mechanisms of the unique efficacy of this technology resulting from the greater depth of penetration and stimulation of wound-healing properties. Salles et al. [23] used fractional CO 2 laser in the treatment of burn scars and reported clinical improvement in 57% of patients (6.8 on a scale of 10). Yet, burn scars appear to have unique and different characteristics. In this study, the burn scar included was of a size and shape that led to its classification as a nonhypertrophic scar. However, burn scars can vary considerably in size and shape and they might require a separate system of classification. Further study is recommended on this subject.
Also, a single patient with acne scar was included. The improvement was fair according to the assessment of the investigator and the blinded dermatologists. FP was used for the treatment of acne scars in over 25 studies [24]. Most of them reported an improvement ranging from mild to moderate. There have been studies that claimed to achieve a mean improvement up to 79.8 [25] and 83% [26]. Most of these studies focused on multiple treatments of up to five treatments or more in improving the outcome of treatment. Similarly, it is better to study acne scars as a separate group because of their unique characteristics.
In this study, there was a highly significant difference ( P ≤ 0.001) in physicians' evaluation and patient satisfaction. This is in agreement with Chua et al. [27], who reported that patient evaluation and a doctor's evaluation can be very similar.
With respect to side effects, FP appeared to be a relatively safe modality of treatment. Treatment was generally well tolerated. Postlaser erythema and edema were observed in all patients. Postinflammatory hyperpigmentation was observed only in three patients and it could be easily controlled with bleaching agents. Fortunately, no other side effects were noted in our patients, although Geronemus [28] reported side effects such as pigmentary changes, infection, and scars following fractional laser therapy.
| Conclusion and recommendation | | |
On the basis of our results, fractional CO 2 laser represents a safe, well-tolerated, effective, and promising treatment modality for the treatment of nonhypertrophic traumatic and postinflammatory scars, with minimal downtime and fewer side effects compared with the traditional laser resurfacing modalities.
Separate clinical trials should be performed to study treatment of burn scars as well as acne scars for their unique characteristics. Further research and data accumulation will help to establish better protocols for each type of scars.
| Acknowledgements | | |
Conflicts of interest
None declared.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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