This study will evaluate the use of free autologous dermal fat grafting (also called free dermal fat autografting) to treat complex craniofacial wounds that have failed standard treatment and to understand how well these grafts work to repair wounds long term. Patients who have undergone free autologous dermal fat grafting to treat complex craniofacial wounds 2-30 years ago will have photographs and small biopsies taken of the area that was grafted.

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.

Inclusion Criteria:

• Underwent free autologous dermal fat grafting carried out by the Study Principal Investigator for one or more complex craniofacial wounds
• Speaks, reads, and understands English
• Willing to freely give consent
• Is able or has a legal representative to give consent

Exclusion Criteria:

• Did not have free autologous dermal fat grafting
• Did not undergo free autologous dermal fat grafting carried out by the Study Principal Investigator
• Underwent free autologous dermal fat grafting carried out by the Study Principal Investigator for an indication other than for one or more complex craniofacial wounds
• Lacks sufficient chart data for study requirements
• Patients for whom it cannot be determined when they underwent free vs injected autologous dermal fat grafting
• Does not speak, read, or understand English
• Unwilling to freely give consent
• Is unable or does not have a legal representative to give consent

Potential patients are drawn from a retrospective cohort of consecutive patients who underwent free autologous dermal fat grafting for one or more complex craniofacial wounds between 1985 and 2018, carried out by a single sub-speciality trained plastic surgeon (Study Principal Investigator).

No individual participant data (IPD) or biospecimens will be shared.