Rationale for localized injection of botulinum toxin type A in spasticity

Injection of botulinum toxin A at the neuromuscular junction may be used to target therapy for spasticity. There have been recent studies in both humans and animals on the quantification of focal paralysis, the location of fibre atrophy and its relationship to the dose, the quantification of muscular paralysis in living subjects and the relationship between clinical effects and different botulinum toxin injection sites. Although botulinum toxin A effects in dogs are potentiated by injection at the motor end-plate, the clinical benefit of this observation has yet to be demonstrated.