Aim: The aim of this study was to determine possible long-term effects of multi-injections of botulinum toxin A (BT-A) on muscle tone and functional abilities in children with cerebral palsy.
Methods: A randomized, single blind study was carried out. Sixty patients with spastic diplegia were enrolled; 40 received 3 successive doses of BT-A to the calf muscle bilaterally at intervals of 3 to 4 months; 20 received no injections and were considered the control group. Evaluation included measurement of muscle tone, passive ankle dorsiflexion range of motion, and gross motor function. The children in the study group were assessed at entry into the study, at 3 months, and at 18 months after the last injection. An identical assessment protocol was applied to the control group, with measurements taken at entry into the study, at 12 to 15 months, and then at 27 to 30 months, roughly corresponding to the time periods set for the study group.
Results: Muscle tone and passive ankle dorsiflexion range showed clinically and statistically significant improvement following BT-A injection at 3 months (P=0.000, P=0.04, respectively) and at 18 months (P=0.005, P=0.007, respectively) compared to the control group, but gross motor function showed significant improvement only at 18 months (P=0.02). Comparison between the first and second evaluations after the last injection in the study group showed a significant improvement in gross motor function and ankle dorsiflexion range (P=0.000 for both parameters); however, muscle tone was significantly increased (P=0.002).
Conclusion: This study gives support to a possible prolonged effect of intramuscular BT-A as an adjunct to conventional physiotherapy to reduce spasticity and improve functional mobility in children with spastic diplegic cerebral palsy.