Changes in Sonoelastography After Using Botulinum Toxin Type A for the Treatment of the Patients with Post-stroke Spasticity: Report of 2 Cases.

We examined the biceps brachii and the medial head of the gastrocnemius muscles on the affected side of two patients with post-stroke spasticity. Sonoelastography was used to evaluate the changes in spastic muscles before treatment; and 2, 4, 8 and 12 weeks after treatment with botulinum toxin Type A. Modified Ashworth scale (MAS), and the passive range of motion of the elbow and the ankle joints, before and after the treatment, were also evaluated. Both patients engaged in outpatient rehabilitation and a home exercise program focused on stretching throughout the assessment period. Sonoelastography enabled the visualization of the hardness of the spastic muscles using imaging and color scaling, and an objective evaluation of the hardness of the spastic muscles was performed by measuring the strain ratio(SR) using an acoustic coupler. Both patients showed reductions in MAS score and SR for both the biceps brachii and medial gastrocnemius head at two and four weeks after injection with botulinum toxin Type A: subsequently, however, these two measures followed different patterns through week 12 of evaluation. SR is an objective measure of spastic muscle hardness based on physical changes in their viscoelasticity, making it qualitatively different from the subjective ratings of the MAS. Sonoelastography offers clinicians a useful tool for visually and objectively monitoring complex pathologies characterized by muscle spasticity at all points in their course: before botulinum therapy and associated rehabilitation, during follow-up, and at the time of repeated injection(s). The information provided could help to select which muscle(s) to target for treatments, and to determine effective dosages. Further accumulation of cases is needed to ascertain and establish useful roles for this tool in clinical practice.