Autologous Nanofat Injection for Cutaneous Scars: A PRISMA 2020 Systematic Review of Clinical Outcomes and Certainty of Evidence

Abstract

Background Cutaneous scarring after surgery, trauma, and burns carries aesthetic, functional, and psychological morbidity. Nanofat, mechanically emulsified lipoaspirate rich in the stromal vascular fraction, has been proposed to improve scar quality, but its clinical benefit, durability, and specificity relative to conventional fat grafting remain uncertain. Objective To appraise the clinical outcomes of autologous nanofat injection for cutaneous scars and grade the certainty of the evidence. Methods Following PRISMA 2020 (PROSPERO CRD420261424355), MEDLINE/PubMed, Embase, Cochrane CENTRAL, and Scopus were searched to 15 April 2026 for clinical studies published from 2021 onward. Two reviewers independently screened records, extracted data in duplicate, and appraised risk of bias with RoB 2 and the NIH tool for before–after studies. Certainty was rated with GRADE. Findings were synthesized narratively and tabulated by effect direction, scar category, and treatment timing. Results Five studies (two randomized, three uncontrolled; 108 patients) were included. In both randomized trials, which applied nanofat at wound closure, scar scores favored nanofat at 3 to 6 months. At 12 months, observer-rated scores remained better in the split-scar trial (n = 12), whereas patient-rated scores and erythema no longer differed. In the three-arm trial, nanofat-enriched fat did not differ from conventional fat grafting in most outcomes. In one uncontrolled series, mean Vancouver Scar Scale score fell by about 45% (10.0 to 5.5) at 3 months, with reduced pain and pruritus. No serious adverse event was reported, but reporting was incomplete. Certainty was low for short-term scar appearance and serious adverse events and very low for longer-term appearance, symptom relief, and nanofat-specific benefit. Conclusion Current evidence suggests a possible short-term effect of nanofat on scar remodeling, particularly when applied at surgical wound closure. A durable, nanofat-attributable benefit remains uncertain, and the available data are too limited to exclude uncommon harm. Adequately powered randomized trials with standardized preparation, validated and objective outcomes, and follow-up of at least 12 months are needed. Registration PROSPERO registration number CRD420261424355.