# Efficacy and safety of fractional CO2 laser therapy combined with triamcinolone acetonide injection for hypertrophic scar: a preliminary systematic review and meta-analysis

## TL;DR

Combining fractional CO2 laser therapy with triamcinolone acetonide injections may improve treatment of hypertrophic scars compared to injections alone, based on a review of clinical studies.

## Contribution

This study is the first to systematically review and meta-analyze the combined use of fractional CO2 laser and triamcinolone acetonide for hypertrophic scar treatment.

## Key findings

- Fractional CO2 laser combined with triamcinolone acetonide significantly reduced scar appearance and symptoms compared to injections alone.
- The combination therapy reduced the risk of skin atrophy but did not increase adverse events.
- Most studies were from China, so results may not generalize to other populations.

## Abstract

This study aims to systematically evaluate the efficacy and safety of fractional CO2 laser therapy combined with triamcinolone acetonide (TA) injection for hypertrophic scar (HS).

Randomized controlled trials (RCTs) investigating the combination therapy of fractional CO₂ laser and TA injection for HS were identified through systematic searches of PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wanfang, Sinomed, and VIP databases from inception to December 2024. The risk of bias was assessed using the Cochrane Collaboration’s Risk of Bias tool. Meta-analysis was performed with RevMan (version 5.3), while sensitivity analysis and publication bias assessment were conducted using Stata (version 14.0). The quality of evidence for outcomes was evaluated with the Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) assessment.

Nineteen studies involving 1,775 patients were included in this meta-analysis. Compared with TA injection alone, the pooled results showed that fractional CO₂ laser combined with TA injection significantly reduced Vancouver Scar Scale scores [MD: −2.52, 95% CI: −3.07 to −1.98, p < 0.00001], pruritus scores [MD: −0.86, 95% CI: −0.94 to −0.78, p < 0.00001], pain scores [MD: −1.04, 95% CI: −1.38 to −0.71, p < 0.00001], scar thickness [SMD: −2.36, 95% CI: −3.12 to −1.61, p < 0.00001], serum TGF-β1 level [SMD: −2.09, 95% CI: −2.71 to −1.46, p < 0.00001], serum VEGF level [SMD: −2.03, 95% CI: −2.90 to −1.17, p < 0.00001], serum EGF level [MD: −17.38, 95% CI: −20.94 to −13.82, p < 0.00001], and serum TNF-α level [SMD: −1.81, 95% CI: −2.77 to −0.85, p = 0.0002]. Regarding safety, the combination of fractional CO₂ laser and TA injection reduced the incidence of skin atrophy [RR: 0.52, 95% CI: 0.34 to 0.80, p = 0.003] compared to TA injection alone. There was no significant difference between the two groups in the incidence of adverse events, including folliculitis [RR: 0.64, 95% CI: 0.30 to 1.35, p = 0.24], erythematous edema [RR: 1.21, 95% CI: 0.68 to 2.16, p = 0.52], skin allergies [RR: 0.38, 95% CI: 0.14 to 1.05, p = 0.06], pigmentation [RR: 1.12, 95% CI: 0.58 to 2.16, p = 0.73], ulcers [RR: 0.35, 95% CI: 0.11 to 1.16, p = 0.09], infections [RR: 1.45, 95% CI: 0.29 to 7.17, p = 0.65], and blisters [RR: 0.33, 95% CI: 0.01 to 7.88, p = 0.50].

Preliminary evidence suggests that fractional CO₂ laser combined with TA injection is an effective treatment for HS. However, due to methodological limitations in the included studies, large-scale, rigorously designed RCTs are required to validate these findings. Additionally, all 19 RCTs were conducted in China with Chinese participants; therefore, the current evidence is limited to this population and requires validation in other ethnic groups.

https://www.crd.york.ac.uk/PROSPERO/view/CRD42025630116, identifier PROSPERO (CRD4202563011).