Effects of botulinum toxin A on calf muscles in children with cerebral palsy: a systematic review

Objective: To assess the efficacy of botulinum toxin A injection for the management of spastic calf muscles in children with cerebral palsy. Data sources: We reviewed all relevant literature indexed in MEDLINE, CINAHL, EMBASE, PEDro and the Cochrane Registered Trials, and also hand reviewed abstracts. Methods: Eligible studies were randomized controlled trials that compared botulinum toxin A injection with any type of treatment or no treatment with identical conditions. We extracted data on calf muscle tone, passive ankle range of motion, gait speed, ankle kinematics and Gross Motor Function Measure, and assessed methodological qualities. Results: Fifteen studies met our inclusion criteria. When botulinum injection was compared with a non-sham control, it was found to be effective at improving calf muscle tone (one month: —2.73 (confidence interval (CI) —3.42 to —2.04), three months: —1.72 (—2.68 to —0.76)), passive ankle range of motion (one month: 3.29 (CI 2.52 to 4.05), three months: 1.00 (CI 0.44 to 1.56)) and gait speed (one month: 0.91 (CI 0.29 to 1.53), three months: 0.61 (CI 0.01 to 1.21)) for four months, as well as Gross Motor Function Measure (2.02 (CI 1.30 to 2.75)) for two months. When compared with sham injection, botulinum injection was only effective on Gross Motor Function Measure (0.98 (CI 0.28 to 1.69)) after four months. Conclusions: Although we found evidence supporting the efficacy of botulinum toxin A in studies comparing botulinum injection with non-sham controls, we did not find clear evidence of support in studies comparing botulinum injection with sham injection.