Ultrasound-Assisted Facial Autologous Fat Grafting: A Systematic Review of Perioperative Safety and Volumetric Outcomes.

High-frequency ultrasound (HFUS) is increasingly used to map facial vasculature and tissue planes, identify prior fillers, and objectively assess volume after autologous facial fat grafting (AFG), but its perioperative benefit has not been systematically synthesized. We performed a PRISMA-compliant systematic review (PROSPERO registration: CRD420251242117), searching PubMed, Embase, Web of Science Core Collection, and the Cochrane Library from inception to November 1, 2025, without language restrictions. We included human clinical studies using B-mode and/or Doppler ultrasound preoperatively, intraoperatively, or postoperatively and reporting safety and/or volumetric outcomes. Methodological quality was assessed using National Institutes of Health tools; due to heterogeneity, findings were narratively synthesized. Twelve studies (885 patients; 2017-2024) were included, predominantly single-center observational designs. Across studies, HFUS supported vascular mapping and filler characterization, real-time confirmation of cannula location within intended planes ("safe layers"), and postoperative monitoring of retention and complications. In a comparative temple augmentation cohort, ultrasound guidance enabled higher injection volumes (22.32±5.19 vs 10.55±2.25 mL) and higher satisfaction (92% vs 74%) without increased complications. Ultrasound-measured retention typically declined during the first 3-6 months and then stabilized, with ∼50-70% retention at 1 year and higher retention after supplementary grafting (49.4% vs 71.7% in one cohort). No study reported blindness, stroke, or skin necrosis; adverse events were generally mild and transient. Overall, HFUS-assisted facial AFG appears promising for risk stratification and objective monitoring, but higher-quality comparative studies with standardized ultrasound protocols and core outcome sets are needed.