Quantifying Effect of Onabotulinum Toxin A on Passive Muscle Stiffness in Children with Cerebral Palsy Using Ultrasound Shear Wave Elastography.

This was a pilot study with nine analysed children, so it cannot establish how BoNT-A works in a wider population. The children were ambulatory at GMFCS levels I to III, and the study did not include enough children at GMFCS levels IV or V, so it says little about more severely impaired patients. One child was excluded because he could not relax during testing, which may have removed children who cannot tolerate the measurement. Some children also received BoNT-A to other muscles in the same session, so effects on the limb cannot be attributed only to the gastrocnemius injection. The BoNT-A dose was not controlled; it was chosen clinically, and the median dose was 3.3 units/kg, on the lower end for a large leg muscle. Ankle range of motion was measured with a goniometer, which has approximately 5° to 14° variability in children with CP, so small range changes could be missed. The authors state that the clinical meaning of the stiffness change remains unclear. The Modified Ashworth Scale reliability has been questioned, which limits confidence in the spasticity scores.

No author conflict-of-interest statement is included in the supplied text. The publication types list NIH extramural research support and non-U.S. government research support.

Do not conclude that BoNT-A increased ankle motion or reliably reduced spasticity. Maximal ankle dorsiflexion and Modified Ashworth Scale changes were not significant, and the stiffness finding came from a nine-child pilot with unclear clinical meaning.