Current Applications and Indications of Allograft Adipose Matrix: A Systematic Review

Background: Autologous fat transfer remains a staple in aesthetic and reconstructive surgery due to its regenerative capacity and tissue integration. However, limitations such as donor site morbidity and unpredictable volume retention persist. Allograft adipose matrix (AAM), a product made from human fat tissue which serves as a natural scaffold to promote adipogenesis, offers a promising alternative, serving as a scaffold for adipogenesis and delivering key extracellular matrix components. This review examines clinical applications and outcomes in soft tissue augmentation. Methods: A systematic review was conducted via PubMed/MEDLINE/Cochrane/EMBASE using “Allograft Adipose Matrix,” “Decellularized Adipose Matrix,” “Renuva,” and “Leneva.” Studies published up to May 30, 2024, involving human or animal AAM treatment were included. Data on demographics, clinical use, injection protocols, outcomes, volume retention, and complications were extracted and analyzed. Results: From 352 studies, 10 involving humans and 9 involving animals were included. Human studies included 93 patients. Indications for AAM included: foot and dorsal hand rejuvenation, abdominal and buttocks contouring, temple atrophy, breast and genitalia augmentation, pressure ulcers, and facial rejuvenation. AAM injection volumes varied, with retention rates ranging from 21.5% to 100%. The most common complications were erythema, swelling, injection site pain, and burning, all resolving easily. Patient satisfaction scores ranged from 72.9% to 100%. Conclusion: AAM provides a promising biomaterial for soft tissue augmentation. Histological analysis supports its role in adipogenesis and neovascularization. Animal studies suggest enhancements through combination therapies, including AAM with autologous fat, platelet-rich plasma, or synthetic scaffolds. Further research is needed to optimize decellularization protocols, improve bioactivity and tissue incorporation. Level of Evidence: Level IV, review article Important Points: - Allograft Adipose Matrix is a promising alternative to autologous fat transfer, offering benefits such as regenerative support, scaffold-based adipogenesis, and reduced donor site morbidity, with various applications. - Clinical studies showed favorable outcomes, including high patient satisfaction and manageable, self-resolving complications. - Further research is needed to enhance efficacy, particularly by improving volume retention, standardizing protocols, and exploring combination therapies, as well as conducting larger, long-term clinical studies.