Botulinum toxin type A: fine-tuning treatment of facial nerve injury.

Treatment of patients following facial nerve injury can be daunting. A multitude of procedures have been developed to treat the paralyzed face. As patients recover from facial nerve injuries, a variety of asymmetries from nerve hypofunction (paresis or paralysis) or hyperfunction (synkinesis or spasm) often persist. Careful use of botulinum toxin type A can be very useful in improving symmetry in acute or chronic facial nerve abnormality by treating the relatively hyperfunctional side.