Botulinum toxin type A in the treatment of lower limb spasticity in cerebral palsy

To determine whether botulinum toxin (BtA) is an effective and safe treatment for lower limb spasticity in children with cerebral palsy. Functional outcomes are of particular interest.

Studies for inclusion in the review were identified using the Movement Disorders Review Group trials register, the Cochrane Controlled Trials Register, MEDLINE, pharmaceutical company databases, communication with other researchers in the field and reference lists of papers found using above search strategies.

Studies were considered eligible for inclusion in the review if they evaluated the efficacy of BtA for the treatment of leg spasticity in children with cerebral palsy. They must have been randomised and include a concurrent control group receiving another intervention.

A paper pro forma was used to collect data from the included studies using double extraction by two independent reviewers. Each trial was assessed for internal validity by each of the two reviewers. Meta-analysis was not possible because results were presented in an incompatable form. A Peto odds ratio was calculated where this was appropriate, otherwise a descriptive summary of the results of the individual studies was compiled.

Three eligible studies were found each with small numbers of subjects. They were short term, used single injection sessions with follow-up of between 4 and 26 weeks. One study (Koman), of twelve ambulant children, compared BtA with injection of a placebo and found non-significant improvements in gait in the BtA group compared to the placebo group. Two studies (Corry, Flett) compared BtA with the use of casts. Each included 20 ambulant children and found improvements in gait, range of ankle movement and muscle tone in both the BtA and cast groups. However there were no significant differences between the groups in either trial. One of these trials (Flett) also assessed motor function using the gross motor function measure (GMFM) (Russell, 1989) and found significant improvements in each group compared to baseline but no significant differences between the groups. The other trial (Corry) performed 3D gait analysis on those children able to co-operate. Maximal plantar flexion and maximal dorsiflexion during walking were both found to be significantly greater in the BtA group compared to the cast group. In all other dimensions there were no significant differences between the groups.

This systematic review has not revealed strong controlled evidence to support or refute the use of BtA for the treatment of leg spasticity in cerebral palsy. Ongoing randomised controlled trials are likely to provide useful data on the short term effects of BtA for leg spasticity. Future research should also assess the longer term use of BtA. Ideally studies should be pragmatic in their approach to dose and distribution of toxin to reflect practise. Outcome measures assessing function and disability would give the most useful information.