Facial reanimations: part I—recent paralyses

Unilateral facial paralysis is a common condition: 1 in every 60 people will experience Bell's palsy during the course of their life, and the residual deficits are particularly problematic for those who do not spontaneously recover the function of the facial nerve. Functionally the most relevant defect is lack of corneal lubrication because of inability to close the eyelid or blink. Morphologically, this presents as obvious ptosis caused by absence of the muscle tone at rest. “Restitutio ad integrum” of a paralysed face by operation is currently impossible, but realistic targets are improvement of facial symmetry and partial recovery of closure of the eyelids and smiling. Movements of the forehead and lower lip tend to be neglected targets for intervention because they are of less functional importance. Recent paralyses are those in which the mimetic musculature may be reactivated by provision of neural input, and the time limit is generally 18-24 months. Electromyography helps to detect it by assessing the presence of muscular fibrillations. If those are not detectable paralyses are considered to be long-standing, and new musculature must be transferred into the face, generally by transplantation of a muscular free flap or of the temporalis muscle in several different ways. When the facial nerve has been severed by trauma or during operation, immediate reconstruction must be considered and the simplest and most efficient is direct neurorrhaphy. If an appreciable part of the nerve is missing and the proximal and distal nerve stumps do not meet, an interpositional nerve graft must be placed to guarantee neural continuity. When reconstruction of the total extracranial branch of the facial nerve is required, the thoracodorsal nerve has proved to be highly effective. In case immediate reconstruction cannot be accomplished and the trunk of the facial nerve is not available as a donor nerve, mimetic musculature may be reactivated by provision of new neural input. Strong inputs from the masseteric or hypoglossus nerves may be mixed with those that arise from branches of the contralateral facial nerve after 2 cross-face nerve grafts have been placed, and good functional recovery is generally obtained. Several ancillary procedures are required to improve the end results in most cases.