Short- medium- and long-term effects of botulinum toxin on upper limb spasticity in children with cerebral palsy: A meta-analysis of randomized controlled trials.

[BACKGROUND] Botulinum toxin (BTX) is an effective management method for spasticity in children with cerebral palsy (CP), but the short- medium- and long-term effects remain unclear.

[OBJECTIVE] The primary objective was to quantify the effects of BTX injections on upper limb spasticity over time in children with CP. The secondary objective was to evaluate efficacy according to the International Classification of Functioning, Disability, and Health-Children & Youth version framework.

[METHODS] We conducted a systematic review and meta-analysis of randomized controlled trials that included control/comparison groups treated with a placebo or other treatments. We searched CINAHL, Embase, PubMed, Scopus, Web of Science, and PsycINFO from their inception to April 2024. The pooled mean difference (MD) or standard mean difference (SMD) with 95 % CI was calculated using a random effects model at the short-term (up to 3 months), medium-term (3 to 6 months), and long-term (over 6 months).

[RESULTS] A total of 658 children with CP aged 1.8 to 19 years old in 12 eligible trials were involved. The primary outcome of the Melbourne Assessment percentile showed a significant increase in the medium- (MD = 2.63, 95 % CI 0.22 to 5.04, I² = 0 %) and long-term (MD = 4.72, 95 % CI 0.93 to 8.51, I² = 0 %) in favor of BTX. Pooled effects also showed that BTX significantly improved Modified Ashworth Scale scores in the short- (MD = -0.44, 95 % CI -0.88 to -0.01, I² = 88 %) and medium-term (MD = -0.20, 95 % CI -0.28 to -0.13, I² = 0 %), and individual goals and bimanual performance up to 6-months. No significantly higher risk of adverse events was observed with BTX.

[CONCLUSIONS AND IMPLICATIONS] BTX injections sustainably improved the quality of affected upper limb function and temporarily improved individual goals and bimanual performance in children with CP. Our findings cautiously support a time interval of 3 to 6 months between BTX injections in the upper limbs of children with CP.

[TRIAL REGISTRATION] This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (Registration ID: CRD42022323672).