Mechanisms of fat and soft tissue filler embolism following aesthetic injections: A cadaveric systematic review.

Background: Fat embolism (FE), fat embolism syndrome (FES), and soft tissue filler embolisms have emerged as significant complications following aesthetic procedures involving fat grafting and soft tissue fillers. Despite increasing reports of embolic events, the anatomical pathways and mechanisms remain poorly understood. We hypothesize that specific anatomical features and injection techniques are associated with increased embolism risk in aesthetic procedures. This systematic review synthesizes cadaveric studies to map vascular pathways, identify high-risk zones, identify high-risk injection instruments and techniques, and improve procedural safety. Methods: A systematic review following PRISMA guidelines was conducted. Cadaveric studies examining fat or filler embolization pathways were included. Animal studies and those lacking full-text availability were excluded. A comprehensive search of PubMed and MEDLINE (2000-2025) was performed without language restrictions. Results: Of 1014 identified studies, 31 met the inclusion criteria. High-risk anatomical zones included the temporal, periorbital, nasal, and gluteal regions. Key vascular structures, such as the middle temporal vein, ophthalmic artery, and deep gluteal vessels, were identified as primary conduits for embolization. Small filler volumes were sufficient to cause severe complications, including blindness, stroke, and pulmonary embolism. Discussion: Anatomical variability significantly influences embolization risk. Study limitations include differences from in vivo conditions and variations in injection techniques. Safer approaches, such as ultrasound guidance, low-pressure injections, and blunt cannulas, are recommended to minimize vascular complications. Other: This study received no funding.