Facial Transplantation: An Anatomic and Surgical Analysis of the Periorbital Functional Unit

Background: Complete loss of eyelid pair is associated with chronic discomfort, corneal ulceration, and visual impairment. Contemporary reconstructive techniques rarely provide functionally acceptable results. Composite tissue allotransplantation may provide a viable alternative. This study reports on neurovascular anatomy and technical details of harvesting an isolated periorbital unit and discusses its functional potential. Methods: Twenty-four hemifaces (12 fresh cadavers) were dissected to study surgically relevant neurovascular structures and to develop an efficient harvest method. Angiographic analysis was performed in seven hemifaces following harvest. Results: The superficial temporal and facial vessels demonstrated consistent location and diameters. Anatomic variability was characterized by the absence of the frontal branch of the superficial temporal artery or facial-to-angular artery continuation, but never of both vessels in the same hemiface. Angiographic analysis demonstrated filling of the eyelid arcades, provided the anastomoses between the internal and external carotid branches were preserved. The facial nerve exhibited consistent planar arrangement and diameters in the intraparotid and proximal extraparotid regions, but less so in the distal nerve course. The inferior zygomatic and buccal branches frequently coinnervated the orbicularis oculi and lower facial muscles with an unpredictable intennuscular course. Based on the foregoing, an effective surgical harvest of the periorbital composite was developed. Conclusions: Surgical harvest of a functional periorbital allotransplant is technically feasible. Revascularization of the isolated periorbital unit is influenced by variations in regional anatomy and cannot be guaranteed by a single vascular pedicle. The orbicularis oculi muscle and its innervation can be preserved, and recovery, albeit without the certainty of reflexive blinking, is expected.