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Prospective study examining remote effects of botulinum toxin a in children with cerebral palsy
Beth E Crowner1, Brad A Racette
1Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri 63108, USA. crownerb@wustl.edu
Insights
Lower-extremity botulinum toxin A injections in children with cerebral palsy did not weaken upper-extremity strength. This study provides crucial data for guiding safe botulinum toxin A dosages in managing spasticity.
Area of Science:
- Pediatric Neurology
- Rehabilitation Medicine
- Movement Disorders
Background:
- Cerebral palsy (CP) is a common neurodevelopmental disorder affecting movement and posture.
- Spasticity is a hallmark of CP, often treated with interventions like botulinum toxin A (BoNT-A).
- Concerns exist regarding potential remote effects of localized BoNT-A injections on muscle strength.
Purpose of the Study:
- To investigate the remote effects of lower-extremity BoNT-A injections on upper-extremity muscle strength and functional status in children with spastic cerebral palsy.
- To determine if the dosage of BoNT-A influences these remote effects.
- To provide evidence-based guidance for BoNT-A treatment protocols.
Main Methods:
- A prospective study involving 34 children (mean age 7.7 years) with spastic cerebral palsy.
- Assessment of upper-extremity muscle strength (shoulder and elbow flexors/extensors, finger flexors) using handheld dynamometry at baseline and 1 month post-injection.
- Evaluation of functional status using the Pediatric Outcomes Data Collection Instrument.
- Analysis of data aggregated and stratified by low-dose (0-10 U/kg) and high-dose (11-25 U/kg) injection groups.
Main Results:
- No significant decline in upper-extremity muscle strength was observed at 1 month following lower-extremity BoNT-A injections.
- No correlation was found between the dose of BoNT-A administered and changes in remote muscle strength.
- Functional status assessments did not reveal significant adverse effects attributable to the injections.
Conclusions:
- Lower-extremity injections of botulinum toxin A, even at higher doses (up to 21 U/kg), do not appear to compromise upper-extremity muscle strength in children with cerebral palsy.
- These findings support the safety of using BoNT-A for managing lower-extremity spasticity in this population without significant remote strength deficits.
- The study aids in refining treatment strategies and dosages for botulinum toxin A in pediatric cerebral palsy management.
Abstract:
We examined the remote effects on muscle strength and functional decline of lower-extremity botulinum toxin A injections in children with cerebral palsy. This prospective study enrolled 34 children (19 boys, 15 girls; mean age, 7.7 years) diagnosed with spastic cerebral palsy. Patients were examined at baseline and 1 month to determine if they experienced a change in upper-extremity strength (handheld dynamometry) or function (Pediatric Outcomes Data Collection Instrument). Subjects were analyzed in aggregate and by dosing group (low dose, 0-10 U/kg body weight; high dose, 11-25 U/kg) to determine if injection dose was associated with a change in remote muscle strength or function. We measured baseline and 1-month postinjection strength in shoulder flexor, shoulder abductor, elbow flexor, elbow extensor, and finger flexor muscles. None of these remote muscle groups was significantly weaker at 1 month after injection. No correlation was evident between change in muscle strength and toxin dose. These findings indicate that doses of botulinum toxin A in the lower extremities, at up to 21 U/kg, do not affect upper-extremity strength. This information can help guide dosages of botulinum toxin A in the management of spasticity in children with cerebral palsy.
