Persistent effect on neuromuscular transmission in patients with primary hemifacial spasm treated with repeated botulinum toxin injections
- Author:
Khean-Jin Goh
;
Chiu-Wan Ng
;
Letchumy P Ramanaidu
;
Mohamed Azly Yahya
;
Chong-Tin Tan
- Publication Type:Journal Article
- From:Neurology Asia
2009;14(2):115-119
- CountryMalaysia
- Language:English
-
Abstract:
Botulinum toxin injection is an effective treatment for hemifacial spasm by causing pre-synaptic
block at the neuromuscular junction. Its effects are temporary and repeated injections are required
to maintain benefi t. Mild, permanent facial weakness is often thought to be due to prolonged nerve
compression. To investigate the possibility of a chronic and persistent effect of botulinum toxin on
neuromuscular transmission, we carried out stimulated single-fi bre electromyography to compare
jitter of the affected orbicularis oculi in previously treated and treatment naïve hemifacial spasm
patients. Previously treated patients were studied when the acute effects of the last botulinum toxin
injection had worn off. We found mean jitter was signifi cantly higher in previously treated patients.
Although, treated patients had longer duration of hemifacial spasm, mean jitter was dependent only
on the number of previous botulinum injections and independent of the duration of hemifacial spasm
and time from the last injection. This suggests a persistent and cumulative effect of botulinum toxin
on neuromuscular transmission in patients treated for hemifacial spasm.
- Full text:P020150902308616766116.pdf
