Effects of different dilutions of botulinum toxin type A treatment for children with cerebral palsy with spastic ankle plantarflexor: a randomized controlled trial.

OBJECTIVE The aim of this study was to investigate the influence of different volumes of saline vehicle on the effects of botulinum toxin type A in reducing ankle plantarflexor spasticity and improving gait pattern in children with cerebral palsy. DESIGN Children with cerebral palsy having ankle plantarflexor spasticity were recruited. They were divided randomly into 2 groups. Botulinum toxin type A mixed with 2 ml or 8 ml saline was injected into the gastrocnemius in each group. Passive range of movement of ankle joint, Modified Ashworth Scale, and results of 3-dimensional motion analysis obtained at pre-treatment, 4, 12, and 24 weeks after treatment were compared. RESULTS Ankle dorsiflexion was increased and ankle plantarflexor spasticity was decreased significantly after botulinum toxin type A treatment. Linear parameters were generally improved, and these improvements persisted until 12-24 weeks. The ankle dorsiflexion angle in the stance phase was also increased, and this increase was maintained until 24 weeks, as revealed by 3-dimensional gait analysis. However, no significantly different effect of varying the amount of saline vehicle was detected. CONCLUSION Botulinum toxin type A improved physical findings and gait pattern in patients with cerebral palsy. The volume of saline mixed with botulinum toxin type A did not result in significant differences in physical evaluation or gait analysis. However, the large-volume group revealed side-effects more frequently and showed no clinical benefits compared with the small-volume group. We conclude that 2 ml of dilution is preferable for botulinum toxin type A treatment in children.