Use of the masseteric nerve to treat segmental midface paresis.

Segmental midface paresis with or without synkinesis reflects incomplete recovery from Bell's palsy, operations on the cranial base or parotid, or trauma, in 25%-30% of cases. To correct the deficit, the masseteric nerve was used to deliver a powerful stimulus to the zygomatic muscle complex, with the addition of a cross-face sural nerve graft to ensure more spontaneous smiling. By doing this, the orbicularis oculi muscle continues to have an appropriate stimulus from the facial nerve, and the zygomatic muscle complex is separately innervated, which considerably reduces synkinesis between the two muscle compartments.