Pathways of sensory recovery after face transplantation.

BACKGROUND: Severely disfiguring facial injuries have a devastating impact on the patient's quality of life. The advent of facial allotransplantation has allowed optimal anatomical reconstruction to be achieved; however, the need for lifelong immunosuppression and unpredictable functional outcomes preclude it from routine acceptance in clinical practice. Evidence from published reports on the first four face transplant recipients indicates improved and accelerated return of sensation to the facial allograft despite suboptimal repair of the sensory nerves.
METHODS: The authors performed a comparative analysis of the sensory outcomes following face transplantation with the sensory recovery achieved after conventional nerve repair, autologous face and scalp replantation, and vascularized free tissue transfer.
RESULTS: Sensory recovery following face transplantation, even when the sensory nerves were not repaired, was comparable to the outcome of microsurgical repair of the peripheral branches of the trigeminal nerve and innervated free flaps.
CONCLUSIONS: Nearly normal sensory recovery can be expected following facial allotransplantation with or without repair of the sensory nerves. The mechanisms responsible for this surprising outcome include preservation of normal density of the receptors within the facial allograft, regeneration from the recipient bed and allograft margins, transmission of the sensory inputs through afferent fibers contained in the facial nerve, nervi nervorum of the facial nerve, or trigeminofacial communicating rami. Furthermore, immunosuppressive therapy with tacrolimus contributes to the accelerated nerve regeneration. The minimum requirements for quantitative sensory testing and timing of the follow-up assessments are outlined to facilitate comparison of sensory outcomes after face transplantation.