Effectiveness of botulinum toxin A for upper and lower limb spasticity in children with cerebral palsy: a summary of evidence

Abstract

Botulinum toxin type A (BoNT-A) therapy has gained wide acceptance in the management of spasticity in cerebral palsy (CP). Clinical experience from numerous case reports and series, retrospective and prospective open label cohort studies, and randomized controlled trials (RCT) has grown over the past 10 years. Several independent systematic reviews on the role of BoNT-A for upper and lower limb spasticity have been written by various authors. The objective of this paper is to summarize past systematic reviews and recent RCT not yet included in the systematic reviews that assess the effectiveness of BoNT-A in upper and lower limb spasticity in children with CP. We reviewed four Class II RCT discussed in five independent systematic reviews and two new Class II trials on the use of BoNT-A alone or with occupational therapy compared to placebo or occupational therapy alone in children with upper limb spasticity. There were 229 children recruited in these six trials and of those, 115 children received BoNT-A in the upper limbs. Five of six RCT showed a time limited decrease in muscle tone most especially at the wrist. Four of six trials showed improvement of hand function on a few specific functional tests. Four systematic reviews concluded that there is insufficient and inconsistent evidence to support or refute the effectiveness of BoNT-A in upper limb spasticity but one recent review recommended that BoNT-A should be considered as a treatment option in upper limb spasticity. For lower limb spasticity, we reviewed 13 RCT discussed in six systematic reviews and two new trials comparing BoNT-A with placebo or other rehabilitation modalities such as physiotherapy, occupational therapy, casting or electrical stimulation. In these studies, 617 children were recruited and of those, 360 children received BoNT-A in the lower limbs. There were six Class I and nine Class II trials. Three Class I trials documented significant improvement in gait pattern in children with gastrocnemius spasticity and one Class I study showed significant reduction in tone in the hip adductors. The most recent review establishes BoNT-A as an effective treatment for equinovarus deformity. Adverse events in these trials were mild and self-limited. The most common complaints were pain in the injection sites and transient weakness. BoNT-A is considered safe for use in children. In conclusion, there is now growing convincing evidence for the time limited beneficial effect of BoNT-A in decreasing muscle tone in children with upper and lower limbs spasticity associated with CP. Decrease muscle tone in the lower limbs translates to improved gait in CP children with spastic equinovarus however more systematic studies are necessary to show sufficient evidence for improved hand function from BoNT-A injection in the upper limbs.