Botulinum toxin A in the hemiplegic upper limb: a double-blind trial.
In a randomised, double-blind study, the effects of intramuscular injection of botulinum toxin type A (BtA) into the upper limb were compared with those of normal saline solution in 14 patients with cerebral palsy; their mean age was 9 years. Range of movement and function were assessed before injection and at 2 and 12 weeks after injection. BtA injection significantly increased maximum active elbow and thumb extension and significantly reduced tone at wrist and elbow. The hand grasp-and-release score improved, representing a modest functional change, but fine motor function, assessed by the ability to pick up coins, did not improve and in some cases deteriorated temporarily. The most notable subjective change was the cosmetic benefit of reduced involuntary elbow flexion. The tone-reducing effect of BtA was clinically detectable in comparison with the placebo and patients and parents perceived the change as beneficial. The median of changes in the treatment group was small but the range was large, suggesting that BtA can be useful in selected patients.
The findings of this single eligible trial support the results of large, open, case-control studies showing a benefit rate between 76 and 100%. This effect size probably makes it very difficult to perform new large placebo controlled trials for hemifacial spasm. Despite the paucity of good quality controlled data, all the studies available suggest that BtA is effective and safe for treating hemifacial spasm. Future trials should explore technical factors such as the optimum treatment intervals, different injection techniques, doses, Bt types and formulations. Other issues include service delivery, quality of life, long-term efficacy, safety, and immunogenicity. BtA should be compared with surgical microvascular decompression.