Evaluation of the effectiveness of botulinum toxin injections in the lower limb muscles of children with cerebral palsy. Preliminary prospective study of the advantages of ultrasound guidance.

The aim of this study was to evaluate the effectiveness of injecting botulinum toxin A into the lower limbs of children with cerebral palsy, according to age, dose, dilution, injection site and needle placement technique (manual or ultrasound guidance).Any child with cerebral palsy examined between May 2005 and May 2006 who needed botulinum toxin A injections in the adductor, hamstring, gastrocnemius and/or soleus muscles could be included. Fifty-four (54) children participated in the study, 30 of whom were injected under ultrasound guidance. The pre- and post- toxin evaluations were done through analytical clinical examination and the Gross Motor Function Measure (GMFM-88).We found an overall clinical effectiveness for 51% of the children. This effectiveness was significantly higher for children under 6 years old or over 12, especially when the doses were greater than 0.8 UI/kg per muscle of Botox, when the injected muscles were hamstrings or gastrocnemius, and when the injections were guided by ultrasound. Dilution had no effect on clinical effectiveness. Function after one month was better for 24% of the children. This functional improvement was significantly better for children under 6 years old with the injections under ultrasound control.This study confirms that the effectiveness of botulinum toxin injections is higher in younger children, with injected doses higher than 0.8 UI/kg per muscle of Botox and injections guided by ultrasound.