Spread And Effectiveness Of Botulinum Neurotoxin A In Spastic Equinus In Cerebral Palsy

Objectives. To study the short-term neurophysiological and clinical outcome of botulinum toxin type A(BoNT-A), injected at standard doses, and assess toxin spread to neighboring uninjected muscles in children with cerebral palsy.

Subjects and methods. The investigators studied 18 ambulatory children with dynamic equinus foot deformity (mean age 6.1 years). The gastrocnemius muscle on the affected side was injected with BoNT-A (Dysport, range from 8.9-19.4 U/kg). As the primary neurophysiological outcome measure, compound muscle action potential (CMAP) areas were assessed in the lateral gastrocnemius (LG) and tibialis anterior(TA) muscles on the treated and untreated side before BoNT-A injections (T0), and on days 10 (T10), and 30 (T30) after injections. Clinical scales were assessed and video gait was analyzed at all three time points.

Results. In all patients, CMAP areas recorded from the LG and TA muscles on the treated side decreased significantly from pre-injection values at T10 (p<0.05) and T30 (p<0.002). Assessment at both time points after injections also showed that ankle spasticity had diminished (p<0.05), equinus foot excursion increased (p<0.05), and functional gait improved (p<0.05).

Conclusion. Although BoNT-A injected at standard doses improves gait in children with spastic equinus foot the toxin spreads to uninjected leg muscles. BoNT-A treatment for cerebral palsy therefore needs individualizing according to the child's clinical features.