Long-term follow-up of cervical dystonia patients treated with botulinum toxin A

We followed the course in 100 consecutive patients with cervical dystonia (CD) after they were initially treated with botulinum toxin (BTX) in the form of Dysport 10 to 12 years ago. A total of 4 patients had died, and 6 were lost to follow-up. Of the remaining 90 patients, 57 (63%) were still treated with BTX. In the patients treated at one centre over the whole period with Dysport, mean dose used during each treatment session was 833 (SD +/- 339) units Dysport with a cumulative dose of 20,943 (SD +/- 9462) units Dysport over a mean of 26.8 (SD +/- 8.6) treatment cycles. Secondary nonresponse was detected in 3 of the 90 patients. During follow-up, 12 patients developed blepharospasm, 13 oromandibular dystonia, and 17 patients writer's cramp. We conclude that BTX remains effective and safe for approximately 60% of CD patients for more than 10 years.