A Single Institution Experience with Standardized Objective and Subjective Scar Evaluation While Undergoing Fractional Ablative Carbon Dioxide Laser Treatment

Recovery in patients undergoing ablative fractional carbon dioxide laser for adult hypertrophic burn scars: A longitudinal cohort study

INTRODUCTION

Ablative fractional carbon dioxide laser (AFCO2L) is widely used as a treatment for hypertrophic burn scars. This study aimed to evaluate clinician and patient-reported outcomes after AFCO2L treatment, safety, and identify factors influencing outcomes.

METHODS

This longitudinal study recruited adult patients with hypertrophic burn scars treated with AFCO2L at a single Australian burn unit. Patients received up to four AFCO2L treatments over approximately 12 months. Outcomes were ultrasound scar thickness, the Patient and Observer Scar Assessment Scale (POSAS), and the Brisbane Burn Scar Impact Scale (BBSIP), measured at baseline and 3, 6, and 12 months after the first AFCO2L treatment. Analysis used mixed effects linear models.

RESULTS

47 patients were included with median age 32 years (IQR: 24, 53) and median burn TBSA of 35 % (IQR: 7.5 %, 48 %). Statistically significant improvements between baseline and 12-month follow-up occurred in scar thickness, and all POSAS and BBSIP subscores. Most improvements remained when accounting for TBSA, Fitzpatrick skin type, scar maturity, and body area treated. Patients reported transient symptoms after 61 of 89 (69 %) AFCO2L treatments, but infection or delayed wound healing occurred after only 4 of 89 (4 %) treatments.

CONCLUSION

This study supports safety and improved clinician and patient-reported outcomes in patients undergoing AFCO2L for hypertrophic burn scars.

Impact of Fractional Ablative Laser Therapy on Function, Symptoms, and Quality of Life in the Management of Traumatic Scars: A Review

OBJECTIVES

A substantial and expanding body of literature addresses the safety and efficacy of fractional ablative laser therapy for traumatic scarring resulting from burns and other trauma. However, available scar research commonly employs standardized assessment scales that generally do not directly address the impact on function and overall quality of life. Unlike past reviews, this manuscript will explore available evidence with a focus explicitly on function and quality of life (QoL) outcomes and de-emphasize surrogate outcome measures that rely primarily on visual characteristics.

METHODS

Through literature review conducted up to January 2024, the authors examined relevant studies focusing on function and quality of life outcomes in traumatic and burn scar management with fractional ablative laser therapy. PubMed, EMBASE, MEDLINE, and Cochrane Library were utilized as primary databases. Reference lists were secondarily reviewed to supplement the literature review process. Studies that did not highlight functional or QoL endpoints or were not in the English language were excluded.

RESULTS

The reviewed studies demonstrated that fractional ablative therapy led to consistent significant and meaningful improvements in functional outcomes, relief from pruritus and pain, and overall enhancements in quality of life for patients with traumatic scarring. Adverse events associated with fractional ablative therapy were infrequent and generally of mild severity, indicating a favorable safety profile.

CONCLUSIONS

The findings from this literature review document ample existing evidence supporting the efficacy and safety of fractional ablative therapy to enhance function, mobility, reduce pruritus and pain, and improve overall QoL. Fractional ablative laser therapy should be integrated more widely into standard management protocols. Given the previous reliance on standardized scar assessment tools that heavily integrate visual characteristics, future studies should prioritize functional and QoL outcomes to further advance scar management protocols and optimize patient care.

Addressing Burn Hypertrophic Scar Symptoms Earlier: Laser Scar Revision May Begin as Early as 3-6 Months After Injury

OBJECTIVES

Fractional ablative CO2 laser (FLSR) is used to treat hypertrophic scars (HTSs) resulting from burn injuries, which are characterized by factors, such as erythema, contracture, thickness, and symptoms of pain and itch. Traditionally, waiting a year after injury for scar maturation before starting laser treatment has been recommended; however, the potential benefits of earlier intervention have gained popularity. Still, the optimal timing for beginning laser intervention in patients with HTSs remains uncertain. This study aims to evaluate the ideal timing for the initiation of FLSR for HTSs using several qualitative and quantitative assessment measures. It was hypothesized that early intervention would lead to similar improvement trends as later intervention, however, would be more ideal due to the shortened time without symptom relief for patients.

METHODS

Patients who received three or more laser treatment sessions and completed both pre- and posttreatment evaluations were included in this analysis (n = 69). FLSR treatment was administered at 4-8-week intervals. Patients starting treatment before 6 months after injury were classified as the early-stage intervention group and those beginning treatment at 6-12 months after injury were classified as the late-stage intervention group. Demographic data, including the age of patients at the time of first treatment, age of scars at the time of first treatment, biological sex, ethnicity, Fitzpatrick skin type, and use of laser-assisted drug delivery, were collected by retrospective chart review. Patients were evaluated on six subjective scales and objectively for scar stiffness with durometry. For all scales, higher scores indicate worse scars. A two-way ANOVA, Student's t-test, and Mann-Whitney U-test were used to compare scores from the pre- to posttreatment evaluations.

RESULTS

There were no significant differences between the groups for any of the demographic or scar-specific variables; thus, differences in outcome can be attributed to the timing of intervention. Both groups demonstrated an improvement in scars with treatment over time (p < 0.05). Both early- and middle-stage initiation showed scar symptom improvement in five out of six scales. In the late-stage intervention, the Patient and Observer Scar Assessment Scale-Patient average score did not show improvement. In the early-stage intervention, the Vancouver Scar Scale total did not show improvement. Quantitative evaluation of scar stiffness by durometry did not show symptom improvement in either group. The Scar Comparison Scale demonstrated the greatest improvement across groups.

CONCLUSION

Laser treatment led to scar improvement in at least one scale at each stage of initiation. Both intervention timelines resulted in equivalent outcomes, and early intervention should be considered when initiating FLSR treatment in burn scars to alleviate symptoms earlier.

Altering CO2 Laser Pulse Energy Settings Did Not Influence Differential Gene Transcription in Normal Skin in a Red Duroc Pig Model

OBJECTIVES

Fractional ablative CO2 lasers are used clinically to treat cutaneous burn scars with reported varying degrees of effectiveness. It was hypothesized that different laser pulse energy settings may lead to differential gene transcription in a porcine model.

METHODS

Uninjured skin from red Duroc pigs was treated with a fractional ablative CO2 laser set to 70, 100, or 120 mJ across the abdomen (n = 4 areas per treatment). Punch biopsies of both treated and untreated sites were taken before treatment (baseline), at 30 min, and at each hour for 6 h and stored in All-Protect tissue reagent. The biopsies were then used to isolate RNA, which was subsequently used in qRT-PCR for eight genes associated with wound healing and the extracellular matrix: CCL2, IL6, FGF2, TIMP1, TIMP3, COL1A2, MMP2, and DCN. RPL13a was used as a housekeeping gene to normalize the eight genes of interest. One-way ANOVA tests were used to assess for differences among laser pulse energies and two-way ANOVA tests were used to assess the differences between treated and untreated areas.

RESULTS

While six of the eight genes were upregulated after treatment (p < 0.05), there were no significant differences in gene expression between the different laser pulse energies for any of the eight genes.

CONCLUSION

While laser treatment is correlated with a positive and significant upregulation for six of the eight genes 4 h after intervention, the pulse energy settings of the laser did not lead to a statistically significant difference in gene transcription among the treatment areas. Different laser pulse energies may not be required to induce similar cellular responses in a clinical setting.

Treatment of hypopigmented burn hypertrophic scars with short-term topical tacrolimus does not lead to repigmentation

OBJECTIVES

Dyschromia is an understudied aspect of hypertrophic scar (HTS). The use of topical tacrolimus has successfully shown repigmentation in vitiligo patients through promotion of melanogenesis and melanocyte proliferation. It was hypothesized that HTSs treated with topical tacrolimus would have increased repigmentation compared to controls.

METHODOLOGY

Full-thickness burns in red Duroc pigs were either treated with excision and meshed split-thickness skin grafting or excision and no grafting, and these wounds formed hypopigmented HTSs (n = 8). Half of the scars had 0.1% tacrolimus ointment applied to the scar twice a day for 21 days, while controls had no treatment. Further, each scar was bisected with half incurring fractional ablative CO2 laser treatment before topical tacrolimus application to induce laser-assisted drug delivery (LADD). Pigmentation was evaluated using a noninvasive probe to measure melanin index (MI) at Days 0 (pretreatment), 7, 14, and 21. At each timepoint, punch biopsies were obtained and fixed in formalin or were incubated in dispase. The formalin-fixed biopsies were used to evaluate melanin levels by H&E staining. The biopsies incubated in dispase were used to obtain epidermal sheets. The ESs were then flash frozen and RNA was isolated from them and used in quantitative reverse transcription polymerase chain reaction for melanogenesis-related genes: Tyrosinase (TYR), TYR-related protein-1 (TYRP1), and dopachrome tautomerase (DCT). Analysis of variance test with Šídák's multiple comparisons test was used to compare groups.

RESULTS

Over time, within the grafted HTS and the NS group, there were no significant changes in MI, except for Week 3 in the -Tacro group. (+Tacro HTS= pre = 685.1 ± 42.0, w1 = 741.0 ± 54.16, w2 = 750.8 ± 59.0, w3 = 760.9 ± 49.8) (-Tacro HTS= pre = 700.4 ± 54.3, w1 = 722.3 ± 50.7, w2 = 739.6 ± 53.2, w3 = 722.7 ± 50.5). Over time, within the ungrafted HTS and the NS group, there were no significant changes in MI. (+Tacro HTS= pre = 644.9 ± 6.9, w1 = 661.6 ± 3.3, w2 = 650.3 ± 6.2, w3 = 636.3 ± 7.4) (-Tacro HTS= pre = 696.8 ± 8.0, w1 = 695.8 ± 12.3, w2 = 678.9 ± 14.0, w3 = 731.2 ± 50.3). LADD did not lead to any differential change in pigmentation compared to the non-LADD group. There was no evidence of increased melanogenesis within the tissue punch biopsies at any timepoint. There were no changes in TYR, TYRP1, or DCT gene expression after treatment.

CONCLUSION

Hypopigmented HTSs treated with 0.1% tacrolimus ointment with or without LADD did not show significantly increased repigmentation. This study was limited by a shorter treatment interval than what is known to be required in vitiligo patients for repigmentation. The use of noninvasive, topical treatments to promote repigmentation are an appealing strategy to relieve morbidity associated with dyschromic burn scars and requires further investigation.

Scar Management and Dyschromia: A Summary Report from the 2021 American Burn Association State of the Science Meeting

Burn scars, and in particular, hypertrophic scars, are a challenging yet common outcome for survivors of burn injuries. In 2021, the American Burn Association brought together experts in burn care and research to discuss critical topics related to burns, including burn scars, at its State of the Science conference. Clinicians and researchers with burn scar expertise, as well as burn patients, industry representatives, and other interested stakeholders met to discuss issues related to burn scars and discuss priorities for future burn scar research. The various preventative strategies and treatment modalities currently utilized for burn scars were discussed, including relatively noninvasive therapies such as massage, compression, and silicone sheeting, as well as medical interventions such as corticosteroid injection and laser therapies. A common theme that emerged is that the efficacy of current therapies for specific patient populations is not clear, and further research is needed to improve upon these treatments and develop more effective strategies to suppress scar formation. This will necessitate quantitative analyses of outcomes and would benefit from creation of scar biobanks and shared data resources. In addition, outcomes of importance to patients, such as scar dyschromia, must be given greater attention by clinicians and researchers to improve overall quality of life in burn survivors. Herein we summarize the main topics of discussion from this meeting and offer recommendations for areas where further research and development are needed.

Treatment of burn hypertrophic scar with fractional ablative laser-assisted drug delivery can decrease levels of hyperpigmentation

BACKGROUND

Laser treatments have been used to treat a variety of scar symptoms, including the appearance of scars following burn injury. One such symptom is hyperpigmentation. There are several qualitative and quantitative measures of assessing improvement in hyperpigmentation over time. The Patient and Observer Scar Assessment Scale (POSAS) and Vancouver Scar Scale (VSS) are two scales that describe characteristics of scar such as pigmentation level. These scales are limited by their qualitative nature. On the other hand, spectrophotometers provide quantitative measures of pigmentation. Prior studies have reported that laser can change scar pigmentation, but no quantitative values have been reported. The current study examines changes in scar melanin index after CO₂ fractional ablative laser scar revision (FLSR) via noninvasive probe measurement in patients of various Fitzpatrick skin types (FST).

MATERIALS AND METHODS

Patients with scars of various sizes and etiologies were treated with FLSR. A database was constructed including 189 patients undergoing laser treatment. From this pool, individuals were selected based on the criteria that they completed at least two laser sessions and had Melanin index measurements for both of these sessions and the pre-operative visit. This criteria resulted in 63 patients of various FST in the cohort. Melanin index, POSAS-Observer (O) and -Patient (P) pigmentation and color scores and VSS-pigmentation scores were examined over time. Demographic information (age of patient at time of first treatment, age of scar at time of first treatment, use of laser-assisted drug delivery (LADD), gender, FST, and Ethnicity) were collected from the medical record. Patients were grouped as "responder" if their Melanin index indicated decreased levels of hyperpigmentation after FLSR treatment in more than half of their total number of visits and "nonresponder" if it did not.

RESULTS

The majority of patients were responders (41/63). In responder patients, measurements of Melanin index showed significantly improved levels of hyperpigmentation in hypertrophic scars after two FLSR sessions (p < 0.05). Age of patient, gender, FST, age of scar, ethnicity, or type of drug delivered by LADD did not predict responder grouping. POSAS-O and -P pigmentation/color scores showed improved scores after two FLSR sessions within the responder group. POSAS-P color scores showed improved scores after two and three FLSR sessions in the nonresponder group. VSS pigmentation scores showed improved scores after three FLSR sessions in the responder group only.

CONCLUSION

Based on Melanin index values, FLSR leads to improvements in hyperpigmentation in certain patients.

Laser-assisted drug delivery of synthetic alpha melanocyte stimulating hormone and L-tyrosine leads to increased pigmentation area and expression of melanogenesis genes in a porcine hypertrophic scar model

OBJECTIVES

One symptom of hypertrophic scar (HTS) that can develop after burn injury is dyschromia with hyper- and hypopigmentation. There are limited treatments for these conditions. Previously, we showed there is no expression of alpha melanocyte stimulating hormone (α-MSH) in hypopigmented scars, and if these melanocytes are treated with synthetic α-MSH in vitro, they respond by repigmenting. The current study tested the same hypothesis in the in vivo environment using laser-assisted drug delivery (LADD).

METHODS

HTSs were created in red Duroc pigs. At Day 77 (pre), they were treated with CO₂ fractional ablative laser (FLSR). Synthetic α-MSH was delivered as a topical solution dissolved in  l-tyrosine (n = 6, treated). Control scars received LADD of  l-tyrosine only (n = 2, control). Scars were treated and examined weekly through Week 4. Digital images and punch biopsies of hyper, hypo-, and normally pigmented scar and skin were collected. Digital pictures were analyzed with ImageJ by tracing the area of hyperpigmentation. Epidermal sheets were obtained from punch biopsies through dispase separation and RNA was isolated. qRT-PCR was run for melanogenesis-related genes: tyrosinase (TYR), tyrosinase-related protein-1 (TYRP1), and dopachrome tautomerase (DCT). Two-way ANOVA with multiple comparisons and Dunnett's correction compared the groups.

RESULTS

The areas of hyperpigmentation were variable before treatment. Therefore, data is represented as fold-change where each scar was normalized to its own pre value. Within the LADD of NDP α-MSH + l-tyrosine group, hyperpigmented areas gradually increased each week, reaching 1.3-fold over pre by Week 4. At each timepoint, area of hyperpigmentation was greater in the treated versus the control (1.04 ± 0.05 vs. 0.89 ± 0.08, 1.21 ± 0.07 vs. 0.98 ± 0.24, 1.21 ± 0.08 vs. 1.04 ± 0.11, 1.28 ± 0.11 vs. 0.94 ± 0.25; fold-change from pre-). Within the treatment group, pretreatment, levels of TYR were decreased -17.76 ± 4.52 below the level of normal skin in hypopigmented scars. After 1 treatment, potentially due to laser fractionation, the levels decreased to -43.49 ± 5.52. After 2, 3, and 4 treatments, there was ever increasing levels of TYR to almost the level of normally pigmented skin (-35.74 ± 15.72, -23.25 ± 6.80, -5.52 ± 2.22 [p < 0.01, Week 4]). This pattern was also observed for TYRP1 (pre = -12.94 ± 1.82, Week 1 = -48.85 ± 13.25 [p < 0.01], Weeks 2, 3, and 4 = -34.45 ± 14.64, -28.19 ± 4.98, -6.93 ± 3.05 [p < 0.01, Week 4]) and DCT (pre = -214.95 ± 89.42, Week 1 = -487.93 ± 126.32 [p < 0.05], Weeks 2, 3, and 4 = -219.06 ± 79.33, -72.91 ± 20.45 [p < 0.001], -76.00 ± 24.26 [p < 0.001]). Similar patterns were observed for scars treated with LADD of  l-tyrosine alone without NDP α-MSH. For each gene, in hyperpigmented scar, levels increased at Week 4 of treatment compared to Week 1 (p < 0.01).

CONCLUSIONS

A clinically-relevant FLSR treatment method can be combined with topical delivery of synthetic α-MSH and l-tyrosine to increase the area of pigmentation and expression of melanogenesis genes in hypopigmented HTS. LADD of  l-tyrosine alone leads to increased expression of melanogenesis genes. Future studies will aim to optimize drug delivery, timing, and dosing.

Laser, Intense Pulsed Light, and Radiofrequency for the Treatment of Burn Scarring: A Systematic Review and Meta-Analysis

Burns and scarring are considered some of the greatest problems in public health because of their frequent occurrence. Today, photo-electric technology shows promising results in the treatment of burn scars. Over the years, more clinical trials and more technologies for scarring have emerged. The aim of this study was to determine better timing and methods of photo-electric therapy for burn scars. This study was registered in PROSPERO (CRD42023397244), following the PRISMA statement, and was carried out in concordance with the PRISMA checklist. In October 2022, we searched PubMed.gov, Embase, and the Cochrane library (1980-present) for published studies related to the photo-electric treatment of burn scars. Two review authors independently selected the studies, extracted the data, assessed the risk of bias among the studies included, and carried out NIH assessments to assess the certainty of the evidence. A third review author arbitrated any disagreements. Our research included 39 studies. We found evidence suggesting that photo-electric therapy between six months and one year offers significantly better outcomes than treatment of scarring after one year. The evidence also suggests the use of IPL for the treatment of early burn scarring. However, it is important to emphasize that the scientific evidence remains insufficient. We need more clinical trials of higher quality and with less heterogeneity to confirm our results.

A Single-Institution Experience About 10 Years With Children Undergoing Fractional Ablative Carbon Dioxide Laser Treatment After Burns: Measurement of Air Pressure-Induced Skin Elevation and Retraction Time (Dermalab) Including Standardized Subjective and Objective Scar Evaluation

Laser treatment has gained more and more importance in the therapy of scars during the last years. Scientific work, especially in children, is scarce on this topic and mostly with an insufficient number of cases or only subjective descriptions. Our study included 77 children from 2012 to 2022 with scars after thermal injury. These were treated at least three times or more by CO2 laser or in combination with pulsed dyed laser (PDL). Beforehand, scar texture and elasticity were determined by a skin elasticity analysis system. Regarding the subjective evaluation, a questionnaire was given to the patients or their parents. Further criteria were the Patient and Observer Scar Assessment Scale (POSAS) and Vancouver Scar Scale (VSS). A statistically significant improvement in elasticity was demonstrated in all scars of any age after each laser treatment. In addition, a significant correlation was found between the number of laser treatments and an increase in elasticity. The assessments of scars after one or more laser sessions by the observer as well as the patient showed a decreasing score in all categories with an increase in the number of laser therapies. The VSS score also improved significantly after each laser session. The mean score before treatment was about 7, after the first laser session, the mean score was already below 6 with a statistical significance. Ninety-six percent of the patients or their parents were satisfied with the laser therapy, and 90% wished to repeat the procedure. This work confirms, by means of the objectification by the scar measurement, the previous scientific works concerning a scar therapy by laser and emphasizes particularly that this can also be used without problems with children with symptomatic scars, contractures, or with cosmetically relevant scars.