Long-term efficacy and safety of botulinum toxin A injections to treat blepharospasm and hemifacial spasm.

BACKGROUND: To evaluate efficacy and safety of botulinum toxin A injections after more than 10 consecutive years of treatment for benign essential blepharospasm and hemifacial spasm.

DESIGN: Retrospective chart review at university-affiliated hospital.

PARTICIPANTS: Study consisted of 64 patients treated with botulinum toxin A injections between October 2005 and May 2006.

METHODS: Inclusion criteria included patients treated with at least one annual botulinum toxin-A injection for more than 10 consecutive years. Data collected included diagnoses and patient characteristics, injection dates, doses administered at each visit, response scores, duration of effect, and adverse events.

MAIN OUTCOME MEASURES: Included changes in doses, response scores, duration of effects, and adverse events between the first and last botulinum toxin A injections.

RESULTS: Thirty-two of 64 patients (mean age at first injection, 57.2 ± 12.4 years; 25 women) met the inclusion criteria. The mean duration of follow up was 14.1 ± 3.1 years (range 10-20 years; mean total visits 44.4 ± 19). A higher mean injection dose per visit was administered during the last year compared with the first year (26.8 ± 10.3 vs. 22.5 ± 7.5 units, respectively) (P = 0.003). The mean durations of effect during the first and last years were 12.4 ± 7.1 and 14.6 ± 7.0 weeks, respectively (P = 0.076). There were no significant differences between genders or between benign essential blepharospasm and hemifacial spasm subgroups. The most common adverse events were ptosis, lagophthalmos and dry eye.

CONCLUSIONS: Botulinum toxin A is an effective, safe, long-term treatment for patients with benign essential blepharospasm and hemifacial spasm. Sustained treatment efficacy required higher doses; however, fewer adverse reactions developed.