Long-term effects of botulinum toxin A in children with cerebral palsy.
The long-term effects of botulinum toxin A (BoNT-A) treatment in children with cerebral palsy (CP) are still elusive. We studied a prospective clinical cohort of 94 children with different subtypes (50% spastic diplegic CP, 22% hemiplegic CP, 25% tetraplegic CP, 3% dyskinetic CP), sex (55% male, 45% female), severity according to Gross Motor Function Classification System (29% Level I, 15% Level II, 16% Level III, 17% Level IV, 23% Level V), and age (median 5y 4mo, range 11mo-17y 8mo). The longest follow-up time was 3 years 7 months (median 1y 6mo) and included a maximum of eight injections per muscle (median two injections to a specific muscle). Outcome measurements were muscle tone (Modified Ashworth Scale) and joint range of motion (ROM). Assessments were made at a minimum before and 3 months after each injection. Ninety-five per cent confidence intervals for differences from baseline were used to identify significant changes. BoNT-A injections induced reduction of long-term spasticity in all muscle-groups examined: the gastrocnemius, hamstring, and adductor muscles. The reduction in tone was most distinct in the gastrocnemius muscle, and each repeated injection produced an immediate reduction in muscle tone. However, improvement in ROM was brief and measured only after the first injections, whereupon the ROM declined. Thus, the results suggest that BoNT-A can be effective in reducing muscle tone over a longer period, but not in preventing development of contractures in spastic muscles. The dissociation between the effects on muscle tone and ROM indicates that development of contractures is not coupled to increased muscle tone only, but might be caused by other mechanisms.
Tedroff
Kristina
K
Neuropediatric Unit, Astrid Lindgren Children's Hospital, Karolinska University Hospital, S-171 76 Stockholm, Sweden. kristina.tedroff@ki.se
Granath
Fredrik
F
Forssberg
Hans
H
Haglund-Akerlind
Yvonne
Y
D000293:Adolescent; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D002547:Cerebral Palsy / Q000145:classification / Q000188:drug therapy* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D009129:Muscle Tonus / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects / Q000503:physiopathology; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D016059:Range of Motion, Articular / Q000187:drug effects; D016896:Treatment Outcome
D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A