Neural repair in facial paralysis: clinical and experimental studies.

Acute facial nerve injuries involving the total facial nerve (n = 202) and its segmental branches (n = 63) were repaired with a variety of neural (n = 225) and myofascial transfer (n = 40). A system for evaluating results based on facial symmetry and tone at rest, recovery of voluntary mimetic activity, synkinesis, and recovery of selective function in discrete facial nerve divisions is presented. The best results were achieved with immediate direct end-to-end neural-epineural anastomotic repairs. The least favorable results were seen with myofascial transpositions and long extratemporal rerouted autologous nerve grafts. A series of tissue culture and animal experiments were used to examine structural changes in neural repair. The requirements for successful motoneuron regeneration, causes of synkinesis and methods for nerve stump coaptation are elucidated. Tubulation experiments demonstrated the need for neurotrophic and neuropromotive factors. Problems associated with the use of autologous nerve grafts are discussed.