Volume 178 - Issue 2
Does intramuscular botulinum toxin A injection improve upper-limb function in children with hemiplegic cerebral palsy?
Authors: H Kerr Graham, Roslyn N Boyd and Darcy Fehlings
Med J Aust 2003; 178 (2): 95-96. || doi: 10.5694/j.1326-5377.2003.tb05084.x
Published online: 20 January 2003
Published online: 20 January 2003
To the Editor: We applaud the efforts of Wasiak et al to apply the principles of evidence-based medicine to answer clinical questions.1 However, it is important to understand the historical context of clinical trials reported in the literature, and, when necessary (eg, when conducting a meta-analysis or when the results of trials appear to conflict), to seek additional information from the authors.
One of us (H K G) designed the randomised-controlled trial (RCT) reported by Corry et al.2 It was a pilot study and not a definitive clinical trial. The primary outcome measure was resonant frequency, an objective measure of muscle stiffness. This trial was conducted before the introduction of validated outcome measures for assessing upper limb function in children with cerebral palsy, and it was not possible to perform any sample size calculation for functional outcomes. At 12 weeks in the group receiving injections of botulinum toxin A, there was a significant difference in grasp and release but not in the ability to pick up coins. It is not surprising therefore that this study found significant decreases in muscle stiffness, but the functional results were inconclusive.
The other RCT identified by Wasiak et al also involved one of us (D F).3 It was designed specifically to investigate functional outcomes, a sample size calculation was performed from pilot work, and a specific functional outcome measure (QUEST) was used. This study reported significant functional improvements after the use of botulinum toxin combined with occupational therapy.
These two studies, when understood in their historical sequence, should therefore be considered complementary and not contradictory. It is important to assess the quality of randomised clinical trials as well as their conclusions (eg, using the Physiotherapy Evidence database PEDRO scale <http://ptwww.fhs.usyd.edu.au/pedro>).4,5 The smaller study by Corry et al2 had insufficient power and inadequate methodology to investigate functional outcomes. On the other hand, the conclusions of the study by Fehlings et al3 should be taken as the current level of evidence. We therefore submit that the conclusion drawn by Wasiak et al is incorrect. We support further research to evaluate and strengthen the evidence relating to botulinum toxin A and upper-extremity function.6
References
- Wasiak J, Hoare BJ, Hender KM. Does intramuscular botulinum toxin A injection improve upper-limb function in children with hemiplegic cerebral palsy? Med J Aust 2002; 177: 158. <eMJA full text>
- Corry IS, Cosgrove AP, Walsh EG, et al. Botulinum toxin A in the hemiplegic upper limb: a double-blind trial. Dev Med Child Neurol 1997; 39: 185-193. i1082020
- Fehlings D, Rang M, Glazier J, Steele C. An evaluation of botulinum toxin A injection to improve upper extremity function in children with hemiplegic cerebral palsy. J Pediatr 2000; 137: 331-337. i1082022
- Verhagen AP, de Vet HC, De Bie RA, et al. The Delphi list: a criteria list for quality assessment of randomised clinical trials for conducting systematic reviews. J Clin Epidemiol 1998; 51: 1234-1241. i1082024
- Boyd RN, Morris ME, Graham HK. Management of upper limb dysfunction in children with cerebral palsy: a systematic review. Eur J Neurol 2001; 8 (Suppl 5): 150-166. i1082026
- Boyd RN, Bach T, Morris ME, et al. A randomised trial of botulinum toxin A (BTXA) and upper limb training — a functional magnetic resonance Imaging and resonant frequency study. Dev Med Child Neurol 2002; 44 (Suppl 91): B9. i1082028