The use of botulinum toxin A in children with cerebral palsy (CP) differs according to their age, sex, and gross motor function, according to a new Swedish study.
The study, “Treatment with Botulinum toxin A in a total population of children with cerebral palsy – a retrospective cohort registry study,” was conducted by researchers at Lund University in Sweden and published in the journal BMC Musculoskeletal Disorders.
Botulinum toxin A (BTX-A, Botox) has been used as a treatment option for spasticity in children with cerebral palsy. When BTX-A is injected into the muscles it reduces muscle tone, usually for 12 to 16 weeks.
Despite being administered for over two decades, there’s still not a consensus about BTX-A treatment indications. Plus, there are only a few studies about the therapy’s use and long-term effects.
With that in mind, researchers aimed to investigate the use of BTX-A in children with CP, taking into account their age, sex, and Gross Motor Function Classification System (GMFCS) level. GMFCS looks at movements such as sitting, walking, and use of mobility devices, and is categorized in five distinct levels — with level V meaning that the child’s gross motor function is severely impaired.
The team also assessed the most common muscle groups treated with Botox, and sought to analyze the differences in the amount of BTX-A given treated children at two time points (2010 and 2015).
Scientists analyzed patients’ medical data from a combined follow-up program and national healthcare registry that contained over 95 percent of all CP children in Sweden.
To facilitate data analysis, researchers designed three groups. Cohort 1 was used to evaluate the link between BTX-A treatment and age, sex, GMFCS level, and muscle groups treated. Within this group there were 3,028 children ages 1-15 (2014-2015).
Cohort 1 results showed 26% percent of children with CP were treated with BTX-A at least once since the previous medical evaluation. BTX-A was most frequently administered in children ages 4 to 6.
Boys were significantly more likely to receive BTX-A treatment compared to girls (28% versus 23%).
The team hypothesized that this might be due to “a bias of the treating provider, or the parents of the child, that boys are expected to be more physically active than girls and that they therefore are more likely to treat boys than girls with BTX-A,” the researchers wrote.
The study also revealed that children with GMFCS III-IV were more likely to receive BTX-A treatment. GMFCS I-III was associated with BTX-A treatment in lower leg muscles, while GMFCS IV-V (worse motor function level) was related to BTX-A in the muscles of the upper leg.
Groups 2 and 3 of the study focused on the differences in the amount of BTX-A treated children during a specific time frame. A total of 736 children ages 3-5 in 2014-2015 were included in cohort 2, while 649 children of the same age in 2009-2010 were part of cohort 3.
Results demonstrated that the proportion of BTX-A treated children did not change significantly between 2009-2010 and 2014-2015.
“Treatment with BTX-A in Sweden varied in relation to age, sex, and GMFCS level. Muscle groups treated also varied with age and GMFCS level and corresponded to the known development of spasticity and muscle contractures. The proportion of BTX-A treatments given has not changed over the past five years,” the team concluded.