CRD Summary: The authors concluded that high quality evidence was too limited and data too conflicting for the efficacy of botulinum toxin type A for upper limb spasticity in children with cerebral palsy to be supported or refuted. This conclusion was supported by the evidence included in the review; but poor reporting of review methodology means that its reliability cannot be assessed.

CRD Commentary: The review question was clear and the inclusion criteria were defined with respect to population and intervention, but not for outcomes or study design. The authors searched some relevant databases; however, the decision to restrict the review to published studies reported in English may have increased the possibility that some relevant studies were not included in the review. This may have introduced publication or language bias. The authors did not report using methods designed to minimise bias and error in the conduct of the review, with the exception of the validity assessment, and they did not report the detail of this assessment beyond the assignment of studies to levels of evidence. Given the heterogeneity of clinical characteristics and design of included studies, the decision to adopt a narrative synthesis appears appropriate. The failure to report statistical data for results means that it is difficult to fully assess the significance of study results. The authors' conclusions are an accurate reflection of the limited and conflicting evidence but, due to poor reporting of review methodology, their reliability cannot be established.