[Functional recovery in hemifacial transplants in rats]

There are a number of different options open to the surgeon for the reconstruction of the face and scalp, but when tissue loss is very extensive, good aesthetic and functional recovery is not possible. Not only must the damaged tissues be replaced, but motor and sensorial functioning also has to be restored.

To evaluate the functional recovery of hemifacial allografts in rats.

Twenty-one hemifacial flaps were transplanted from Long-Evans rats to Wistar-Lewis rats, under immunosuppression monotherapy with tacrolimus. Prior to the operation, anatomical and allograft viability studies were conducted. Two groups of transplanted rats were formed: with or without nerve repair. In the nerve repair group, end-to-end suture was employed to repair the infraorbital branch of the trigeminal nerve and the buccolabial, upper mandibular marginal and zygomatico-orbital branches of the facial nerve. Sensory recovery was evaluated by filming traction of the whiskers, whereas motor recovery was assessed by blind tests using electromyography studies of the mystacial muscles and electroneurography of the facial nerve. At eight weeks, the animals were sacrificed and biopsy samples were taken from the mystacial region.

The facial flap was successfully lifted in 10 cases. In the nerve repair group both clinical and electrophysiological recovery were observed at six weeks, whereas biopsy samples taken in the eighth week showed recovery of the nerve fascicles.

The hemifacial flap can be transplanted. By repairing the nerves of the allograft, it is possible to achieve its functional recovery, as can be confirmed clinically, electrophysiologically and histopathologically. To date, this is the first evidence of functional recovery following a hemifacial transplant in rats.