Preclinical Animal Models in Facial Transplantation

The technical feasibility and clinical applicability of facial transplantation (FT) have been demonstrated, yet animal models with different technical nuances and allograft compositions continue to be developed. We sought to provide a comprehensive appraisal of the current scope and value of animal models in FT. METHODS: A comprehensive review of the literature was performed to identify all studies relevant to preclinical animal FT. Abstracts, texts, and references were screened. Both large and small animal models in studies including survival experimental arms were included. Purely anatomical or cadaveric animal studies were excluded, as were non-English language articles. RESULTS: Twenty-nine unique models were identified, including 10 large (nonhuman primate, swine, and canine) and 19 small (rabbit, rat, and mouse) animal models. Orthotopic models were described in 70% of large and 73.7% of small animal studies. One study described a 2-stage rat FT model. Nerve coaptations were performed in 20.7% of all models (1 canine, 1 rabbit, and 4 rat models). One rat model allowed the study of both functional recovery and cortical reintegration of the allograft. Survival rates and immunological outcomes varied per model and protocol. CONCLUSIONS: A comprehensive review of animal models in FT shows redundancy spanning a variety of species, allograft compositions, and experimental designs. Although initial studies have focused on safety and technical feasibility, recent advances present specific opportunities for refining our understanding of functional and immunological challenges. As clinical experience continues to evolve, animal models may play an increasingly modest yet targeted role in FT.