The Effect of Fat Grafting on Scars Hyperpigmentation: A Systematic Review and Meta-Analysis

Background: Hyperpigmented scars, particularly in exposed body areas, can be difficult to conceal and may evoke psychological distress. While the precise causes of scar dyschromia are not fully understood, alterations in melanogenic activity appear to hold more significance than changes in melanocyte quantity. Current treatments encompass laser interventions. However, it is essential to consider their costs and potential complications in relation to their limited proven effectiveness. Fat grafting has gained interest as a scar modulation technique due to its regenerative properties, and its efficacy in reducing scar hyperpigmentation is currently under investigation. Methods: A systematic review and meta-analysis was reported according to PRISMA guidelines. PubMed, Embase, and Cochrane Library databases were accessed. PROSPERO registration number is CRD42023457778. The primary outcome was a change in scar pigmentation after fat grafting. Pigmentation changes after fat grafting were calculated using the standardized mean difference (SMD) between baseline and postoperative scores according to POSAS and VSS scales. Bias assessment was conducted according to the National Institute for Health and Clinical Excellence quality assessment tool. Results: A total of 8 articles meeting inclusion and exclusion criteria were identified, involving 323 patients with hyperpigmented scars treated with fat grafting. A significant difference in scar pigmentation was noted after treatment with fat grafting according to observers’ ratings, with a SMD of − 1.09 [95% CI: − 1.32; − 0.85], p<0.01. The SMD for patient-reported scar pigmentation after treatment with fat grafting was − 0.99 [96% CI: − 1.31; − 0.66], p<0.01. Four studies provided objective measurements of melanin changes after fat grafting and revealed inconsistent findings compared to subjective observations. Conclusions: Fat grafting shows promise in ameliorating hyperpigmented scars based on subjective assessments, but further corroborating evidence from objective measures is required. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.