Primary objective was to identify changes in ultrasound images of spastic medial gastrocnemius (MG) before and after temporary motor point block (MPB). Secondary objective was to measure clinical response to MPB.
This prospective study recruited 11 participants with spastic hemiparesis. The less-affected limb served as control. Modified Ashworth Scale (MAS) was the clinical spasticity measure. Ultrasound outcome measures included pennation angle (PA), muscle thickness (MT), and echointensity (E). Low intensity electrical stimulation and 3 cc of an equal mixture of lidocaine (1%) and bupivacaine (0.5%) was used for the MG MPB. After 30 minutes, clinical and ultrasound assessments were repeated. Image analysis was completed using Image J. Statistical analysis used Signed Rank test to evaluate response pre- and post-injection.
There was no significant difference in PA (P = 0.734), MT (P = 0.160), or E (P = 0.846) after MPB of spastic MG. MAS decreased post-MPB from 3 ± 0.63 to 1.82 ± 0.98 (P = 0.002).
This pilot study demonstrated decreased spasticity of the MG after temporary motor point block without corresponding improvements in MA as measured by muscle ultrasound. Improving MA changes in spastic muscle may require more long-term spasticity treatment or additional interventions. Limitations of this study were the small sample size and controlling for spastic limb position when obtaining pre- and post-injection ultrasound images. Further studies are needed to delineate when alterations in MA occur and the impact over time with more aggressive and/or earlier treatment of spastic muscle.
Bridget Walker– Fellow Physician, Medical College of Wisconsin
Sergey Tarima– Associate Professor, Medical College of Wisconsin
Rachel Minkin– Clinical Research Coordinator, Medical College of Wisconsin
Jennifer Nguyen– Clinical Research Assistant, Medical College of Wisconsin
John McGuire– Professor, Medical College of Wisconsin