Refinement in the rehabilitation of the paralyzed face using botulinum toxin.

A number of surgical procedures exist to improve facial symmetry for patients with facial paralysis. Whereas static symmetry is often improved, dynamic asymmetry frequently persists because of the imbalance of complex coordinated movements of facial expression. The paralyzed face is often distorted by the excessive pull of the normal contralateral face during emotional expression. This study reports an expanded clinical indication for botulinum toxin in patients with unilateral facial paralysis. Ten patients with facial paralysis and markedly asymmetric smiles were treated with botulinum toxin A injections into the contralateral zygomaticus major, levators labii superioris and angulii oris, or risorius muscles. Eight of the 10 patients noted improvement in the symmetry of their smiles and underwent repeat injections. The onset and duration of effect averaged 5.9 days and 3 months, respectively. Botulinum toxin therapy provides a safe and efficacious modality for refining the appearance of the paralyzed face during mimetic activity.