Botulinum toxin and cerebral palsy: time for reflection?

Abstract

Botulinum toxin A (BTX-A) is increasingly being used in early management of spasticity in ambulant children with cerebral palsy (CP), with the aim of improving function, promoting muscle growth, and delaying the need for surgical intervention. However, there is a lack of evidence about the long-term outcome of BTX-A injections. The focus on spasticity as the predominant problem in younger children with spastic CP may not fully consider the associated muscle weakness. It also raises concern that although BTX-A may improve function in the short term, it has the potential to affect muscle growth and function adversely in the long term. A cautious approach to the early use of BTX-A, with the use of objective outcome measures within a specialized multidisciplinary setting, is recommended, particularly in ambulant children with spastic diplegic CP, until further evidence is available on the long-term outcome of early BTX-A injections in children with CP.

The effects of botulinum toxin injection frequency on calf muscle growth in young children with spastic cerebral palsy: A 12-month prospective study

“…Concerns have been expressed regarding the possible long-term effects of BoNT-A injections on muscle growth in children with CP because of the potential for denervation atrophy, weakness and impaired function [9][10][11]. Such concerns are, in part, based on animal studies that report reductions in the size and strength of the injected muscle [12][13][14], as well as adjacent muscles [15], following BoNT-A injection.…”

Botulinum toxin and its orthopaedic applications

“…Before injection, clinical examination must be directed specifically towards differentiating spasticity from fixed contracture, although minimal degrees of contracture may improve with BTX-A injections. 33 It is hoped, but not proven, that in young children the instigation of all elements of non-operative management such as physiotherapy, casting, orthotics and spasticity management including the use of regular BTX injections may delay or decrease the need for surgical intervention 34 reserving single-event multi-level surgery for fixed musculotendinous contractures and bony deformity in the older child. 35 In the lower limb, several randomised, double-blind, placebo-controlled trials have proved the short-term efficacy and safety of BTX-A in the management of spasticity, with improvements in deformity and gait.…”

Letter to the Editor

“…SIR-We write in response to the above review by Gough et al 1 We commend Gough, Fairhurst, and Shortland for their timely, balanced, and clearly expressed view of the role of botulinum toxin A (BTX-A) in cerebral palsy (CP) and the Editor of the journal for publication of this important review.The premise that 'the use of BTX-A is based on the concept that muscle fibres in children with spastic CP are short, and that weakening the muscle with BTX-A injections will allow them to be stretched and, thus, to grow longitudinally' is not exactly what we had in mind from our experimental studies in the hereditary spastic mouse, 2 or in pilot work in the use of BTX-A in children with CP. 3 The view that sarcomere numbers are reduced and fibre length decreased in spastic muscle is not well supported by the literature as reviewed by Foran et al 4 However, there is much stronger evidence for shortening of the muscle belly, with compensatory increased length of the tendon and shortening of the entire muscle-tendon-unit (MTU), all of which result in abnormal posturing and decreased joint range of motion.…”

“…SIR-We write in response to the above review by Gough et al 1 We commend Gough, Fairhurst, and Shortland for their timely, balanced, and clearly expressed view of the role of botulinum toxin A (BTX-A) in cerebral palsy (CP) and the Editor of the journal for publication of this important review.…”