Botulinum toxin to improve lower facial symmetry in facial nerve palsy.

INTRODUCTION: In long-standing facial palsy, muscles on the normal side overcontract causing difficulty in articulation, eating, drinking, cosmetic embarrassment, and psychological effects as patients lack confidence in public.
METHODS: We injected botulinum toxin A (BTXA) into the normal contralateral smile muscles to weaken them and restore symmetry to both active and passive movements by neutralising these overacting muscles.
RESULTS: A total of 14 patients received BTXA (79% women, median age 47 years, average length of palsy 8 years). They were all difficult cases graded between 2 and 6 (average grade 3 House-Brackmann). All 14 patients reported improved facial symmetry with BTXA (dose altered in some to achieve maximum benefit). Average dose was 30 units, but varied from 10 to 80 units. Average time to peak effect was 6 days; average duration of effect was 11 weeks. Three patients had increased drooling (resolved within a few days).
CONCLUSION: The improvement in symmetry was observed by both patient and examining doctor. Patients commented on increased confidence, being more likely to allow photographs taken of themselves, and families reported improved legibility of speech. Younger patients have more muscle tone than older patients; the effect is more noticeable and the benefit greater for them. BTXA improves symmetry in patients with facial palsy, is simple and acceptable, and provides approximately 4 months of benefit. The site of injection depends on the dynamics of the muscles in each individual patient.