Botulinum toxin for spasticity in children with cerebral palsy: a comprehensive evaluation

Spasticity is a prevalent disabling clinical symptom for children with cerebral palsy. Treatment of spasticity with botulinum toxin in children with cerebral palsy was first reported in 1993. Botulinum toxin provides a focal, controlled muscle weakness with reduction in spasticity. Interpretation of the literature is difficult because of the paucity of reliable measures of spasticity and challenges with measuring meaningful functional changes in children with disabilities.

This study documents the effects of botulinum toxin A injections into the gastrocnemius muscles in children with spastic diplegia. Outcomes are evaluated across all 5 domains of the National Centers for Medical and Rehabilitation Research domains of medical rehabilitation.

A randomized, double-masked, placebo-controlled design was applied to 33 children with spastic diplegia with a mean age of 5.5 and Gross Motor Function Classification System Levels of I through III. Participants received either 12 U/kg botulinum toxin A or placebo saline injections to bilateral gastrocnemius muscles. Outcomes were measured at baseline and 3, 8, 12, and 24 weeks after injection.

Significant decreases in the electromyographic representation of spasticity were documented 3 weeks after botulinum toxin A treatment. A significant decrease in viscoelastic aspects of spasticity was present at 8 weeks, and subsequent increases in dorsiflexion range were documented at 12 weeks for the botulinum toxin A group. Improvement was found in performance goals at 12 weeks and in maximum voluntary torque and gross motor function at 24 weeks for the botulinum toxin A. There were no significant differences between groups in satisfaction with performance goals, energy expenditure, Ashworth scores, or frequency of adverse effects.

The safety profile of 12 U/kg of botulinum toxin A is excellent. Although physiologic and mechanical effects of treatment with botulinum toxin A were documented with functional improvement at 6 months, family satisfaction with outcomes were no different. Communication is needed to ensure realistic expectations of treatment.