Laser plus PLLA shows numerically lower scar severity than laser monotherapy for atrophic acne scarsAdding PLLA or PRP to Laser May Improve Acne Scars

BackgroundAtrophic acne scars represent heterogeneous structural problems rather than a single treatment indication. This review compared minimally invasive, energy-based, and regenerative interventions and discussed, at a conceptual level, how sparse comparative evidence might generate phenotype-aware hypotheses for future trials.MethodsThis PROSPERO-registered PubMed/PMC-based review (CRD420261471957) searched PubMed/MEDLINE and PMC open-full-text records from inception to 20 June 2026. The database-limited strategy was chosen to prioritize records with verifiable source tables and reproducible aggregate data for exploratory network meta-analysis. Reference lists and accessible trial-registry records were checked for supplementary verification, but Embase, CENTRAL, Web of Science, Scopus, ClinicalTrials.gov, WHO ICTRP, and grey-literature sources were not systematically searched; therefore, eligible studies outside the PubMed/PMC-accessible evidence base may have been missed. Randomized and split-face randomized trials reporting extractable clinical scar-severity outcomes were synthesized using frequentist random-effects network meta-analysis; clinical heterogeneity was assessed by node definitions, treatment protocols, device platforms, outcome scales, and effect modifiers, with sensitivity analyses varying assumed within-person correlations for split-face trials.ResultsNine randomized trials, 19 treatment arms, 11 direct comparisons, and 10 nodes formed a sparse connected network. Compared with laser monotherapy, numerically lower post-treatment severity point estimates were observed for laser plus PLLA (SMD −0.69, 95% CI −1.55–0.18; 95% prediction interval −1.80–0.42), laser plus PRP (SMD −0.20, 95% CI −0.81–0.40; 95% prediction interval −1.12–0.72), and microneedling plus chemical peel (SMD −0.14, 95% CI −1.34–1.07; 95% prediction interval −1.53–1.25), although all confidence and prediction intervals crossed the null. No closed loop from independent designs was available for formal inconsistency testing. Heterogeneity was moderate to substantial (tau2 = 0.124; I2 = 65.3%, 95% CI 0.0% to 92.1%), most nodes were supported by one or two studies, and sensitivity analyses changed the top-ranked treatment; therefore, P-scores were treated only as descriptive exploratory statistics and a reliable treatment ranking does not currently exist. CINeMA rated comparisons as low or very low confidence. No included trial reported treatment effects by scar morphology, so phenotype-based comparative efficacy could not be tested.ConclusionsSome combination strategies had numerically lower point estimates, but the network is too sparse and uncertain to support a dependable treatment hierarchy or any definitive between-treatment claim. Because included trials did not report phenotype-stratified results, the phenotype-guided component should be read only as a conceptual, hypothesis-generating interpretation and not as phenotype-specific treatment guidance.Evidence certaintyLow to very low across network comparisons; exploratory therapeutic evidence synthesis rather than a definitive treatment-ranking claim.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD-420261471957, PROSPERO: CRD420261471957.