BotulinumtoxinA Improves Spasticity in Adults With Cerebral Palsy

Zohra S. Lassi, PhD

A recently conducted systematic review evaluated the effectiveness of intramuscular botulinumtoxinA (BTX-A) in adults with spastic cerebral palsy (CP), finding it improved spasticity-related outcomes, but results were inconclusive for other functional outcomes. 

Investigators included a total of 6 studies in the review, 2 of which were focused specifically on adult patients with CP, and the remaining 4 studies included mixed patient populations with movement disorders, traumatic brain injury, CP, and other conditions utilizing therapy for spasticity.

The Ashworth Scale, Modified Ashworth Scale (MAS), or the visual analog scale were used to assess BTX-A in improving spasticity across 5 studies, with all treatment groups showing spasticity improvement. Four studies included mixed study populations, but the sole study focusing on only adults with CP found a 30% improvement in spasticity from baseline, evaluated using the visual analog scale, which was deemed clinically relevant. At 8 weeks, 16 of 33 patients in the treatment group reported spasticity improvement, compared to 9 of 33 in the placebo group (relative risk, 1.83 [95% CI, 0.95-3.53]). Although, when evaluated again at 16 weeks, investigators did not identify a difference between the groups. 

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“Overall, there are limited studies on the effectiveness of BTX-A in the management of spasticity-related outcomes among adult persons with CP,” study coauthor Zohra S. Lassi, PhD, National Health and Medical Research Council, Robinson Research Institute, the University of Adelaide, Australia, et al wrote. “Future studies using a scale to objectively assess functional gains among adults with CP will be beneficial. Few authors have used improvements in QOL and reduction in carer burden as positive outcomes after spasticity management in this population.”

Gait analysis was investigated in 2 studies, comprised exclusively of patients with CP, with mixed results. One study observed improvement in stride length, peak hip flexion, and peak knee flexion during the swing phase when using BTX-A, but no improvement in Gait Deviation Index. Comparably, the second study did not find any benefit of BTX-A in lower limb sagittal kinematics when compared with placebo. 

Joint range of motion was analyzed in 2 studies using goniometry, with 1 study reporting significant improvement in joint range of motion in the treatment group, as well as improvement in both treatment and placebo groups when compared to placebo at the 3-week mark. The second study did not present results on improvement in joint range of motion, but 5 out of 41 patients with CP did show an improvement in activities of daily living.

One study evaluated quality of life (QOL), finding no significant differences between placebo and treatment groups when using the Short-Form 36 questionnaire when comparing to baseline at 8 and 16 weeks. Patients in the BTX-A group did have significant improvement of vitality at the 8-week mark, but not at 16 weeks, and both placebo and treatment groups had significant improvement in bodily pain.

Investigators noted the absence of the Tardieu Scale and the Modified Tardieu Scale (MTS), which can be used before and after BTX-A intervention to improve accuracy in spasticity assessment, when used in combination with the MAS. Additionally, investigators were limited as there were several mixed assessment tools amongst included studies, as well as differing follow-up periods.

No serious adverse events related to treatment were reported in any of the included studies. Some patients did report mild adverse events related to the intervention, primarily pain at the injection side, headache, nausea, and fatigue. Future studies will be required, focusing exclusively on cohorts of adults with CP, evaluating QOL and using patient satisfaction scales. 

REFERENCE

Andraweera ND, Andraweera PH, Lassi ZS, Kochiyil V. Effectiveness of botulinum toxin A injection in managing mobility-related outcomes in adult patients with cerebral palsy. Am J Phys Med Rehab. Published online September 1, 2021. doi:10.1097/PHM.0000000000001653