Fat to the Future, Dermal Time 2: Long Term Clinical and Histological Status of Free Dermal Fat Autograft Recipient Sites: Cross-Sectional Assessment in a Retrospective Cohort Treated for Complex Craniofacial Wounds

Complex craniofacial wounds (CCW) are those considered to be refractory to initial reconstructive and antibiotic treatment and may involve chronic infection, exposed hardware, irradiated local tissue, and soft tissue volume loss. They are a functional, aesthetic, quality-of-life, and economic burden and have many aetiologies and impact patients of all ages from diverse socio-economic and geographical backgrounds. The present study will evaluate if free dermal fat autografts (DFA) can serve as a less involved, more dynamic approach than the standard of microvascular flaps to facilitate healing and reconstruction for CCW. A previous 33-year retrospective study of free DFA for CCW indicated recipient graft sites healed and remained volume-stable in most patients. To evaluate the long-term viability of this modality, clinical and histological assessments of free DFA recipient and undisturbed tissue at donor sites will be carried out in patients from the original cohort. In the present study, it will be first determined if free DFA continues to provide stable long-term outcomes for prevention of infection and hardware exposure and stable volume and contour results. Then, it will be determined if free DFA recipient sites retain normal, expected histology and immune cells (dermal lymphocytes, macrophages, and mast cells). Finally, it will be evaluated if the long-term free DFA recipient site tissues are significantly different from undisturbed tissue at donor sites with respect to the presence of adipose tissue and populations of immune cells. The present study will be the first to (1) evaluate the long-term fate of free DFA recipient sites in this complex craniofacial wounds, (2) determine the presence of immune cells within free DFA recipient sites, and (3) compare the long-term differences of free DFA recipient and undisturbed tissue at donor sites. Outcomes from this project will serve as the basis of understanding of free DFA survival and function in treating CCW and provide an investigative framework for more rigorous follow-up studies to define indications and refine techniques for free DFA use in this context and more generally.