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Page 2 of 8 Palmer et al. Plast Aesthet Res 2020;7:2 I http://dx.doi.org/10.20517/2347-9264.2019.34

Keywords: Face transplantation, mandibular reconstruction, allograft design, bimaxillary transplantation, temporomandi-
bular joint reconstruction, computerized surgical planning, computer-aided design and manufacturing, intraoperative
navigation

INTRODUCTION
Face transplantation offers significant aesthetic and functional improvements for patients with devastating
injuries that cannot be managed with conventional reconstruction [1-3] . Including the first procedure
[2,4]
performed in 2005, 44 face transplantations have been reported in the scientific literature to date .
Successful transplantations have demonstrated the feasibility of this procedure and paved the way for
[3,4]
technique refinement and increased operative complexity . Surgeons are now able to include vascularized
[4,5]
bone in addition to soft tissue in facial allografts . The ability to incorporate varying amounts of donor
facial skeleton allows the development of grafts that are customized to a patient’s individual defect and
[2,5]
reconstructive goals . While many autologous reconstructive options for the mandible exist, they may fail
to correct severe defects in some patients . Modern face transplantation therefore represents a powerful
[6]
tool for surgeons seeking to reconstruct massive facial defects involving the mandible.

Use of osteomyocutaneous allografts in this setting requires thorough planning and meticulous execution.
To improve facial aesthetics and mandibular function, transplantation must not only replace missing or
defective mandible; it is also necessary to restore proper spatial relationships between the mandible and
[4,7]
other skeletal elements including the midface and skull base . Establishing these relationships starts with
thoughtful allograft planning based on an understanding of how the skeletal components included in the
graft and the locations of osteotomies and osteosyntheses will influence functional outcomes. Precision in
the subsequent steps of allograft harvest and inset is challenging and imperative. In many cases, recipients
have endured injuries and reconstructive procedures that can disfigure anatomy and make graft alignment
[7,8]
difficult . Furthermore, when the recipient’s defect warrants an allograft including both the midface and
mandible, attachment of the graft is complicated by the paucity of recipient landmarks other than the skull
[4,9]
base and the potential for misalignment in three dimensions . Observed outcomes have reflected the
procedural challenges, as transplants involving the maxilla and mandible have been associated with trismus,
[4,7]
malocclusion, and impaired airway function, for example . To avoid these functional complications and
best restore this critical anatomy, transplants involving the mandible require detailed planning and precise
[4]
execution .

This review seeks to define some of the important considerations in the surgical planning of facial allografts
involving the mandible as well as to highlight some of the emerging technologies available to optimize
patient outcomes in these cases.

DESIGNING THE MANDIBLE-CONTAINING ALLOGRAFT
One of the earliest considerations in planning for facial transplantation to correct a mandibular defect is
how much donor skeleton to include in the allograft. Given the goal of restoring function and appearance,
it follows that, in the case of patients with defects involving both the maxilla and mandible, reconstruction
with an allograft including both of these skeletal components is most appropriate [2,10] . Determining the
extent of donor bone inclusion is more controversial in the case of patients with defects limited to only the
mandible. In such circumstances, some advocate for transplantation of only the affected jaw while others
support bimaxillary transplantation [4,11,12] .

In 2011, Gordon et al. [13,14] introduced through cadaveric studies the concept of “hybrid occlusion”, or
the occlusal relationship achieved after allotransplanataion between the donor maxilla and recipient’s