Treatment of Focal Muscle Overactivity Using Botulinum Toxin Injections

Botulinum toxin, a neurotoxin produced by the bacteria Clostridium botulinum, has been used in the management of neurologic disorders. There are currently four formulations of toxin available for use in the United States: onabotulinumtoxinA (Botox®), abobotulinumtoxinA (Dysport®), incobotulinumtoxinA (Xeomin®), and rimabotulinumtoxinB (Myobloc®). This chapter describes the mechanism of action, pharmacology, guidelines for use, and techniques for administration of botulinum toxin in the management of adult upper and lower limb muscle overactivity in the context of spasticity. Additionally, it discusses the importance of goal attainment scales and optimization of the clinical response. The clinician must remember that botulinum toxin has only been shown to be efficacious in the symptomatic control of muscle overactivity, without a proven role in disease modification. Rehabilitation therapy, in addition to the administration of botulinum toxin, is necessary to improve functional outcomes.