Use of Shear Wave Elastography for Quantitative Assessment of Muscle Stiffness After Botulinum Toxin Injection in Children With Cerebral Palsy.

[OBJECTIVES] This study aimed to investigate the stiffness of the gastrocnemius (GC) muscle with acoustic radiation force impulse (ARFI) elastography after botulinum toxin-A (BTX-A) injection in children with spastic cerebral palsy (CP) and to examine the relationship between elastographic and clinical parameters.

[METHODS] This prospective randomized single-blind controlled clinical study included 49 lower extremities of 33 children with spastic CP. They were randomized into 2 groups: group 1 (n = 25 extremities in 17 children) received BTX-A injection and a home-based exercise program; group 2 (n = 24 extremities in 16 children) received only a home-based exercise program. Patients were evaluated in pretreatment and posttreatment periods in the first and third months with ARFI elastography, the Modified Ashworth Scale, Modified Tardieu Scale, Pediatric Functional Independence Measure, Gross Motor Function Classification System, and goniometric range of motion measurement of the ankle.

[RESULTS] A statistically significant difference was found in elastography of the GC muscle in group 1 only at the first month after treatment (P < .05). No statistical difference was found in elastography of the GC after treatment in group 2. According to the Modified Ashworth Scale, Modified Tardieu Scale, and ankle passive range of motion, group 1 showed significant improvements after treatment (P < .05). Also, there was a significant correlation between these clinical parameters and elastographic measurements (P < .05).

[CONCLUSIONS] According to the results of this study, the measurements from ARFI elastography combined with clinical parameters might be useful for evaluation of spasticity after BTX-A treatment in children with CP. Also, they might be useful in distinguishing patients who will benefit clinically, especially in the early stages of treatment.