Botulinum Toxin A Injection in Treatment of Upper Limb Spasticity in Children with Cerebral Palsy: A Systematic Review of Randomized Controlled Trials

Cerebral palsy (CP) is the most common cause of childhood disability globally. Botulinum toxin A injections are widely used to manage limb spasticity in children with CP. Intramuscular botulinum toxin A has been used in the upper limbs of children with CP to manage preoperative and postoperative pain, facilitate nursing, and achieve functional and/or cosmetic improvement of hand position. These goals are achieved primarily through reduction of spasticity. The aim of this review was to assess the evidence for the effect of botulinum toxin A injections used to manage upper limb spasticity in children with spastic CP. Specifically, we examined the role of botulinum toxin A as an adjunctive treatment to other physical therapy modalities. Additionally, we analyzed the associated complications. METHODS: The literature extraction process involved 4 phases: identification, screening, eligibility, and inclusion. We used a combination of Google Scholar, PubMed, and ScienceDirect. The choice of the search terms was based on the Medical Subject Headings. We extracted the relevant studies using a combination of words or terms related to (1) patient population, (2) pathology, (3) clinical intervention, and (4) anatomical distribution of pathology. Studies were included if they were randomized controlled trials conducted on children and/or adolescents with CP targeting the upper extremities in which botulinum toxin A was used as an adjunctive treatment to a primary intervention. RESULTS: The literature extraction process yielded 15 randomized controlled trials for inclusion in this review. The total number of participants enrolled in the included studies was 499, with 255 in the intervention group (51%) and 244 controls (49%). All participants in the eligible studies had unilateral spastic CP except for those in 4 studies (27%) with 198 participants (40%) that included a heterogeneous sample of unilateral and bilateral spastic CP. The mean age of participants in the intervention group ranged from 2.6 to 10.7 years among the individual studies. The mean age of participants in the control group ranged from 3.1 to 10.55 years among the individual studies. This review indicated that botulinum toxin A had a positive effect on the degree of spasticity and cosmetic appearance of the injected upper limb. The results with respect to functional gains and quality of life were either conflicting or not significant. CONCLUSIONS: Randomized controlled trials of botulinum toxin A injection in the treatment of upper limb spasticity in children with CP used variable outcome measures and yielded mixed results. Overall, there is some evidence to support the use of botulinum toxin A as an adjuvant treatment to other physical therapy regimens or placebo to reduce spasticity in the short term. There is insufficient evidence to support its use as an adjunctive treatment to improve upper limb function or quality of life. The complications were acceptable and did not outweigh the clinical gains incurred. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.