Limited Evidence of Functional Benefit After Upper Limb Botulinum Toxin Treatment in Children With Cerebral Palsy: Systematic Review and Meta-analysis.

Studies used many different upper limb and hand measures, and a sizeable number did not report data in a usable form, which made pooling and interpretation difficult or impossible. Unilateral and bilateral involvement could not be separated, even though 83% of the children had one side affected and the two groups use their arms very differently. Only single injections could be assessed; repeated injections, which are common in practice, were not evaluated. Blinding is difficult because tone visibly changes, and parents and therapists frequently guess which child was injected, so the very positive parent ratings may be inflated. Few studies reported quality of life, activity or participation, and none of those results reached significance, so the review says little about them. Publication bias could not be assessed because so few studies were available, and certainty was very low for the Assisting Hand Assessment and low for the COPM because of small patient numbers. One included study was funded entirely by the maker of Botox and eight others had partial pharmaceutical company support.

The review itself received no specific funding from any source and the authors declare no competing interests. Among the studies they included, eight of 14 had partial support from pharmaceutical companies and all declared the funder did not influence the study; one study was initiated and funded entirely by Allergan, the producer of Botox.

Do not read the strong parent ratings and better goal scores as proof that the arm works better. The objective tests of upper limb function did not reach significance, the average differences were smaller than the tests can detect, and the authors themselves note that parents and therapists can usually guess which children had the injection. Grip also got weaker while the toxin was active, so a child who looks more comfortable is not necessarily a child with a stronger or more useful hand.