DOI: 10.14457/tu.the.2017.803
title: Efficacy of combining fractional carbon dioxide laser and silicone gel in the treatment of hypertrophic scars and keloids: a split-lesion, evaluator-blind, randomized, controlled trials

description: Background: Hypertrophic scars and keloids are common problems found in the population. Despite the public and some medical professionals’ perspective, these types of abnormal scars do not cause only an aesthetic problem. On the contrary, it can affect patients ’quality of life by causing disturbing symptoms, e.g., pruritus, pain, and contracture. Intralesional corticosteroid injections, the most widely used modality for the treatment of hypertrophic scars and keloids has various side effects including skin atrophy, telangiectasia, and hypopigmentation with vary in success rate. In recent studies, the effectiveness of fractional carbon dioxide laser (AFCO2) and liquid silicone gel (LSG) was promisingly shown in scars treatment with minimal side effects. Therefore, this study aimed to investigate the efficacy of combining a film-formingLSG with AFCO2 in the treatment of hypertrophic scars and keloids on the hypothesis that these 2 modalities could have       a synergist effect. This combination could be a novel treatment modality for hypertrophic scars and keloids that is effective and safe from the adverse effects of steroids.  Objective: To evaluate the efficacy and safety of combining AFCO2 with LSG in the treatment of hypertrophic scars and keloids comparison with LSG or AFCO2 alone.  Methods: 24 consecutive scars (8 hypertrophic scars and 16 keloids) from 15 subjects were randomly allocated into 2 groups. One group received AFCO2 and LSG treatment on one half while another half received only LSG treatment. Another group received AFCO2 and LSG therapy on one half while another half received only AFCO2 treatment. 3 sessions at 4 weeks intervals (day 0, 4th week, 8th week) of AFCO2 was performed with pulse energies ranged from 70-90 mJ, peak power 30 W, treatment density 100 spots/cm2, 2 passes, and 120μm spot size. LSG was applied twice daily for 12 weeks. Assessment of scars was done at baseline, 4th week, 8th week and 16th week. Vancouver scar scale (VSS) and the Patient and observer scar assessment scale (POSAS) were used for evaluating the improvement of scars. Standardize photography, and biometric measurements were used to document change and measure hemoglobin (erythema) and melanin index.  Results: A combination of AFCO2 and LSG yielded a significant improvement in the treatment of hypertrophic scars and keloids confirmed by a statistically significant decrease in VSS and both patient and observer parts of POSAS. Comparing to AFCO2 alone or LSG alone, a combination of AFCO2 and LSG showed a higher decrease in a mean difference of VSS and both parts of POSAS, and also showed a higher component of significantly improved parameters of POSAS from bothevaluator and patients’ perspective. Mean difference from VSS and Total POSAS (both observer and patient scale) showed the highest reduction from baseline to last visit from AFCO2 and LSG treated sites (FS), while AFCO2 alone (FLA) and LSG alone treated sites (SG) showed lesser and the least reduction, respectively (VSS: -1.8 ± 1.8, -1.4 ±1.7, -1.1 ± 1.1; Observer scale: -6.2 ± 5.4, -5.2 ± 6.7, -3.9 ± 4.5; Patient scale: -9.3 ±13.6, -8.9 ± 14.5, -7.3 ± 10.3; respectively). All treatments showed a significant decrease in VSS and total observer scale, but total patient scale showed a significant decrease only for FS, while FLA and SG showed a non-significant decrease. Observer scale of FS showed a significant decrease in almost all parameters of POSAS (pigmentation, thickness, relief, pliability, and surface area) except vascularity. Hemoglobin index of FS and FLA rose up at 4th week and 8th week. FS showed declining of hemoglobin at 16th week, while FLA’s hemoglobin index continued to rise. However, repeated measure ANOVA comparing between FS, SG, and FLA could not show a statistically significant difference between 3 treatments. Except for the subgroup analysis of keloids that showed a statistically significant difference between FS and SG in total and overall opinion of POSAS (observer part). Biometric measurements showedno statistically significant change in melanin index of all 3 treatments, while hemoglobin index showed rising in FS and FLA. However, at 16th week or 8 weeks after the last laser session, both FS and FLA showed a downward trend of hemoglobinindex.  No severe or irreversible complication liked skin atrophy, telangiectasia, and hypopigmentation was found throughout this study.  Conclusion: FS showed significant improvement in the VSS, observer and patient POSAS (almost all parameter). Moreover, this treatment combination also showed the significant improvement of observer total score and overall opinion observer score of POSAS in the treatment of keloid subgroup. Hence, these treatment options could be a promising modality for the treatment of hypertrophic scars and keloids. Further investigation would be required to affirm the superiority of a combination of AFCO2 and LSG over a monotherapy of AFCO2 or LSG alone in the treatment of hypertrophic scar and keloid.