Does botulinum toxin treatment affect the ultrasonographic characteristics of post-stroke spastic equinus? A retrospective pilot study

Equinovarus/equinus foot is a pattern most commonly treated with botulinum toxin type A in patients with post-stroke spasticity involving the lower limbs; the gastrocnemius is the muscle most frequently injected. Spastic equinovarus/equinus can present a mixture of conditions, including spasticity, muscle/tendon shortening, muscle weakness and imbalance. In this study, we wanted to determine whether botulinum toxin treatment affects the ultrasonographic characteristics of post-stroke spastic equinus. The same dose of AbobotulinumtoxinA was injected into the gastrocnemius medialis and lateralis of 21 chronic stroke patients with spastic equinus. Clinical (Ashworth scale and ankle range of motion) and ultrasound (conventional and sonoelastography) evaluation of the treated leg was carried out before and 4 weeks after injection. No significant effects of botulinum toxin treatment on the ultrasonographic characteristics of spastic equinus were observed. As expected, there were significant improvements in ankle passive dorsiflexion range of motion and calf muscle spasticity at 1 month after treatment. There was a direct association between Achilles tendon elasticity and calf muscle spasticity at baseline evaluation. Larger studies with a long-term timeline of serial evaluations are needed to further investigate the possible effects of botulinum toxin injection on spastic muscle characteristics in patients with post-stroke spasticity.