Botulinum toxin type A injections in the spastic upper extremity of children with hemiplegia: child characteristics that predict a positive outcome

Abstract

Evidence is increasing to suggest that botulinum toxin type A (BTX-A) plays a role in the management of upper extremity spasticity in the paediatric population. However, little information is available on the clinical characteristics of the child that predict a response to this intervention. Our research group previously published a randomized controlled trial demonstrating that BTX-A injection improves function of the upper extremity of children with spastic hemiplegia. In the present paper, we evaluate the child characteristics that predict a positive response to the BTX-A injections in the randomized treatment group. The treatment group was divided into positive functional responders and nonresponders using a cut score of a change of 10 points on the Quality of Upper Extremity Skills Test (QUEST). A two-way analysis of variance procedure was done comparing the following baseline characteristics: function as scored on the QUEST and the Pediatric Evaluation of Disability Inventory (PEDI) self-care domain, grip strength, upper extremity spasticity and age. Grip strength was significantly higher in responders with a P-value of 0.001. Young age approached significance with a P-value of 0.05. Correlation of change scores on the QUEST with baseline characteristics in the treatment group yielded similar results. BTX-A causes a reduction in spasticity and strength; we postulate that if the hand is weak initially, BTX-A can decrease hand function. Two case reports are presented that highlight the importance of grip strength and age.

A randomized controlled trial comparing botulinum toxin A dosage in the upper extremity of children with spasticity

“…For instance, when injecting muscles of the forearm and hand, grip strength may be affected. A study by Fehlings et al 5 outlines the importance of adequate baseline grip strength in predicting a positive response to the upper extremity BTX-A injections. The dependence on adequate grip strength poses a potential problem with the use of a high dose of BTX-A.…”

“…The high dose was in the range of BTX-A that is in current clinical usage and in published articles. 3,5,[7][8][9] The low-dose group received 50% of the dosage of the high-dose group for each muscle group injected. We hypothesized that a low dose would be more effective because it would permit a reduction in tone and subsequent improvement in function without causing significant weakness.…”

Costs and consequences of botulinum toxin type A use

“…This is not surprising since over 60% of both cohorts were tetraplegic and up to another 34% were either diplegic or hemiplegic. Moreover, it has been reported that if the hand is weak initially, botulinum toxin can decrease hand function [12].…”

The Concept of «Key Muscles» and the Early Onset of Botulinum Therapy in Spastic Forms of Cerebral Palsy

“…Использование многоуровневых инъекций средни-ми дозами БТА (12-15 Ед/кг) показало свою эффектив-ность в коррекции эквинусной деформации стоп [26], улучшении функции голеностопного сустава [27,28], силы захвата кисти [29] и общей двигательной активности пациентов с ДЦП. Более того, в ряде работ было показа-но, что средние дозы были более эффективными по срав-нению с низкими дозами, использованными в первых исследованиях [23,30].…”