Selecting Target Vessels and the Location of Nerve Repairs In Facial Composite Tissue Allotransplantation

Purpose: To further optimize facial composite tissue allotransplantation.

Methods and Materials: Cadaver studies, single case review (Boston face transplant recipient with 22-month follow-up), 13 candidates preoperative planning sessions.

Results: Transplantation of the entire face, including all soft tissues, the maxilla, and the mandible anterior to the insertion of the masseter, can be safely performed based on the facial vessels alone. However, to include the hair-bearing scalp and/or ears, the superficial temporal vessels must be dissected, which could increase the duration and complexity of the procedure, as well as blood loss. Bilateral external carotid anastomoses can lead to oropharyngeal ischemia (1) due to unique blood supply to the tongue by lingual arteries. Furthermore, several connections occur between internal and external carotid territories. One of the critically important ones is in the ophthalmic artery territory. In certain anomalies, the ophthalmic artery can be primarily supplied by angular artery, which following diversion of bilateral external carotid arteries can lead to ocular ischemic syndrome (2). Unilateral external carotid anastomosis appears to be safe, especially if performed distally to the lingual artery take off, however, bilateral external carotid anastomoses are not recommended unless extensive vascular pre-operative evaluation clarifies the communication between external and internal carotid artery angiosomes.

For nerve repair, individual branches of the facial nerve should be re-connected because neurorrhaphy at the facial nerve trunk leads to less targeted re-innervation and risks synkinesis. Proprioception and sensory feedback is critical for cortical allograft functional re-integration (3). Reconnection of as many sensory nerves as possible such as supraorbital, infraorbital, buccal, great auricular and mental should also be performed.

 Conclusions: An entire facial allograft can be based on the facial vessels alone, and both sensory and motor nerve coaptation should be part of the operation.

 References:

1.    Dittmar M, Spruss T, Shuierer G, et al. External carotid artery territory ischemia impairs outcome in the endovascular filament model of middle cerebral artery occlusion in rats. Stroke. 2003 Sep;34(9):2252-7.

2.    Alizai AM, Trobe JD, Thompson BG, et al. Ocular ischemic syndrome after occlusion of both external carotid arteries. J Neuroophtalmol. 2005. Dec;25(4):268-72.

3.    Dubernard JM, Lengele B, Morelon E, et al. Outcomes 18 months after the first human partial face transplantation. N Engl J Med 2008 May 15;358(20):2179-80.