Dermatology · Medical Literature
[Meta-analysis of the effects of PDL combined with fractional carbon dioxide laser in the treatment of hypertrophic scars in children].
Abstract
Objective: To evaluate the effects of pulsed dye laser (PDL) combined with fractional carbon dioxide laser in the treatment of hypertrophic scars (HSs) in children. Methods: This study was a meta-analysis. Databases including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, and VIP Chinese Journal Service Platform were retrieved to obtain the publicly published retrospective and prospective studies on the effects of PDL combined with fractional carbon dioxide laser for pediatric HS from the establishment of each database to October 31, 2024. The outcome indexes included the total score of the patient and observer scar assessment scale (POSAS) and laser treatment-related adverse reactions. Stata version 16.0 software was used to conduct a meta-analysis. Results: A total of 7 studies were included, involving 348 children with HSs. Meta-analysis results showed that the total POSAS scores in HS children who received PDL combined with fractional carbon dioxide laser treatment were significantly lower than those before treatment (with a standardized mean difference of -7.76, a 95% CI of -10.91 to-4.61, P 3 months group), intervention measures, and fractional carbon dioxide laser energy parameters might be sources of heterogeneity for the total POSAS score. The incidence of adverse reactions of PDL combined with fractional carbon dioxide laser for pediatric HS was 3.50% (with a 95% CI of 1.60% to 6.00%, P 0.05). Conclusions: PDL combined with fractional carbon dioxide laser is beneficial for the recovery of pediatric HS, with a low rate of adverse reactions and a favorable safety profile. For pediatric HS, the early intervention window within 3 months after scar formation should be prioritized, and a regimen combining low-energy fractional carbon dioxide laser flexibly with PDL should be adopted to achieve better therapeutic outcomes.
Clinical relevance
In children with hypertrophic scars, does treatment with pulsed dye laser (PDL) combined with fractional carbon dioxide laser significantly reduce scar severity as measured by the Patient and Observer Scar Assessment Scale (POSAS), and what is the associated adverse reaction profile? __SNAPSHOT__ {"studyDesign":"Systematic review with meta-analysis (retrospective and prospective studies included)","setting":"Multi-database search (PubMed, Embase, Cochrane Library, Web of Science, CNKI, Wanfang, VIP); predominantly Chinese clinical centers based on included literature; affiliated with Department of Burn and Wound Repair Surgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China","sampleSize":"n=348 children across 7 included studies","population":"Pediatric patients with hypertrophic scars (HSs); at least 296 of 348 had burn-induced HSs; precise age range not reported in abstract","intervention":"Pulsed dye laser (PDL) combined with fractional carbon dioxide laser","comparator":"Pre-treatment baseline (within-patient before-after comparison); no concurrent untreated control group reported across included studies","primaryOutcome":"Total score on the Patient and Observer Scar Assessment Scale (POSAS); secondary outcome: incidence of laser treatment-related adverse reactions","followUp":"Not reported (individual study follow-up durations not specified in abstract)","fundingSource":"Government (National Administration of Traditional Chinese Medicine Co-constructed Science and Technology Project GZY-KJS-SD-2023-071; Natural Science Foundation of Shandong Province ZR2024MH021; Shandong Traditional Chinese Medicine Science and Technology General Program M-2023037)"}
Key findings
The pooled meta-analysis of 7 studies (n=348 children) demonstrated a statistically significant reduction in total POSAS scores following PDL combined with fractional CO2 laser treatment compared to pre-treatment baseline (standardized mean difference [SMD] = −7.76; 95% CI: −10.91 to −4.61; P<0.05). The use of SMD rather than weighted mean difference indicates that included studies used heterogeneous scoring scales or reporting formats, making absolute POSAS point reductions non-calculable from the available data. NNT cannot be calculated from the reported effect measure. The pooled incidence of adverse reactions was 0.04 (4%; 95% CI: 0.02–0.06; P<0.05), suggesting a low overall rate of treatment-related adverse events; specific adverse reaction types (e.g., erythema, blistering, dyspigmentation) were not individually enumerated in the abstract. Subgroup analyses identified geographic distribution, scar duration, intervention protocol specifics, and fractional CO2 laser energy parameters as potential sources of heterogeneity in POSAS outcomes. Publication bias was not detected across total POSAS score analyses, subgroup analyses, or adverse reaction data (P<0.05 for all Egger or Begg tests, per abstract). The degree of heterogeneity (I² statistic) was not reported in the provided abstract.
Practice implications
This meta-analysis provides pooled evidence that PDL combined with fractional CO2 laser is associated with statistically significant improvement in hypertrophic scar scores (POSAS) in the pediatric population versus pre-treatment baseline, with a low reported adverse event rate of approximately 4%. However, several important caveats limit the certainty and generalizability of these findings. First, the comparator is pre-treatment status, not a concurrent untreated or active-comparator control group, meaning natural scar maturation cannot be ruled out as a contributor to observed improvements — a critical limitation given that hypertrophic scars may regress spontaneously over months to years. Second, the majority of included patients (≥296/348) had burn-induced HSs, limiting applicability to non-burn hypertrophic scars. Third, subgroup analyses suggest significant heterogeneity driven by geography, scar chronicity, treatment protocols, and laser energy parameters, which complicates direct translation to a standardized clinical protocol. Fourth, optimal treatment timing, number of sessions, laser energy parameters, and inter-session intervals remain incompletely characterized. The authors suggest early intervention within 3 months of scar formation and the use of low-energy fractional CO2 laser settings as potentially superior, but these conclusions are based on subgroup analyses and require prospective validation. Only the abstract was available for review; full-text inspection may reveal additional methodological details including risk-of-bias assessments, individual study designs, and heterogeneity statistics not reported here. __LIMITATIONS__ Before-after design within included studies: no concurrent untreated control group, making it impossible to separate treatment effect from natural scar maturation,Small aggregate sample size (n=348 across 7 studies) with likely small individual study sample sizes,High anticipated heterogeneity across included retrospective and prospective studies (I² not reported in abstract); use of SMD implies scale or reporting variability across studies,Predominantly burn-induced HSs (≥85% of patients), limiting generalizability to other etiologies of hypertrophic scarring,Follow-up duration not reported; long-term durability of treatment effect is unknown,Specific adverse reaction types, severity grading, and individual incidence rates not detailed in abstract,Subgroup findings (early intervention, low-energy settings) are hypothesis-generating and not derived from prospective randomized comparisons,Predominantly Chinese-center literature base may limit geographic and ethnic generalizability,Inclusion of both retrospective and prospective study designs introduces variable risk of selection bias and confounding,Absence of active comparator (e.g., PDL alone, CO2 laser alone, or standard of care) precludes conclusions about the additive benefit of combination over monotherapy in children specifically __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ PDL combined with fractional CO2 laser produces statistically significant improvements in POSAS scores in pediatric hypertrophic scars, with a low pooled adverse event rate (~4%), but the absence of concurrent untreated controls means natural scar maturation cannot be excluded as a confound. The evidence base is small (7 studies, n=348), heterogeneous, and predominantly derived from burn-injured children in Chinese centers, limiting broad generalizability. Combination laser therapy appears safe and promising in this population, but prospective randomized controlled trials with active comparators and longer follow-up are needed before definitive practice recommendations can be established.