Treatment of dystonia with botulinum A toxin: a retrospective study of 170 patients.

OBJECTIVE: Botulinum A toxin has been reported to provide excellent symptomatic relief for patients with dystonia. To analyse the treatment, complications, and outcome of patients receiving botulinum A toxin injection, the case records of 170 patients attending the Botox Clinic at the Kwong Wah Hospital from 1 December 1992 to 31 December 1996 were reviewed. Of these 170 patients, 130 (76.5%) had idiopathic hemifacial spasm, 18 (10.6%) had blepharospasm, 18 (10.6%) had spasmodic torticollis, and 4 (2.4%) had generalised or focal limb dystonia. One hundred and sixty-six (97.6%) patients were Chinese. The average dose of botulinum A toxin required for an optimal response was 14.54 U for those with hemifacial spasm, 49.64 U for those blepharospasm, and 137 U for those with spasmodic torticollis. Among patients with hemifacial spasm, 103 (81.7%) gave a good response, 21 (16.7%) gave a partial response, and there was no response in two (1.6%) patients. The corresponding figures for patients with blepharospasm were 7 (38.9%), 10 (55.6%), and 1 (5.6%), respectively, and for those with spasmodic torticollis, the figure were 6 (37.5%), 6 (37.5%), and 4 (2.5%), respectively. Complications from botulinum A toxin injection were rare (less than 10%), minor, transient, and usually dose-related. In conclusion, idiopathic hemifacial spasm was the most common type of movement disorder encountered in our Botox Clinic and botulinum A toxin injection was safe and effective in the majority of patients.