Botulinum toxin A (BoNT-A) for spasticity in adults. What is the evidence?

There are now many reports from open, uncontrolled studies which suggest that botulinum toxin A (BoNT-A) is valuable in treating spasticity. Evidence of its benefit is also gradually accumulating from randomized controlled trials (RCTs). In this presentation I will discuss the reasons why RCT evidence is being generated, and describe the findings currently available, including preliminary results from as yet unpublished trials. RCT data have been reported for leg and arm spasticity in a variety of diseases, but predominantly in stroke and multiple sclerosis patients. In most RCTs, the effects of BoNT-A are compared with placebo over a single injection cycle. The outcomes are generally positive and support the use of BoNT-A. However, data from RCTs are less convincing than those from open studies for a variety of technical reasons. These especially reflect the difficulties of finding good outcome measures for such a heterogeneous array of patients. There is good evidence that BoNT-A has clinical benefit in treating the mechanical effects of spasticity. In order to further clarify its usefulness, future research should address the strategies of short- and longer-term use of BoNT-A, and the unresolved technical issues of how to get the best out of this new treatment.