Effectiveness and safety of the modified multiple mode procedures versus traditional multiple mode procedures on treating facial atrophic acne scars: a propensity score matching retrospective cohort study.

Multiple mode procedures (MMP) of fractional CO₂ laser provide higher efficacy and shorter downtime in treating acne scars, compared to traditional fractional CO₂ laser therapy. This study aims to evaluate the effectiveness and safety of modified MMP integrated with fractional microneedle radiofrequency (FMR), ultra-pulse CO₂ laser and fractional CO₂ laser in treating acne scars. A retrospective analysis of 162 acne scar patients treated with MMP or modified MMP was conducted. Acne scars were evaluated using the Echelle d'Evaluation Clinique des Cicatrices d'Acné (ECCA) grading scale, modified Manchester Scar Scale (mMSS), and Global Assessment Scale (GAS). Baseline variables were balanced with propensity score matching (PSM) to improve the comparability of treatment effectiveness and safety between groups. Among 162 patients with facial acne scars, 68 were treated with modified MMP and 94 with traditional MMP. After PSM, both groups had 55 patients with comparable baseline characteristics (P > 0.05). The ECCA score decreased more significantly in the modified MMP group (60%±11%) than in the MMP group (45%±16.6%, P < 0.001). The modified MMP group also had higher mMSS color score (2.6 ± 0.7 vs. 2.1 ± 0.9, P = 0.005), greater reduction in pore size and skin laxity (P < 0.001), shorter postoperative erythema duration (22.2 ± 4.0 vs. 31.3 ± 3.7 days, P < 0.001), but higher pain scores (Visual Analogue Scale, VAS: 6.7 ± 1.6 vs. 3.8 ± 0.8, P < 0.001). Modified MMP is more effective than traditional MMP in treating acne scars, especially for patients with large pores and skin laxity.