Functional impact of different muscle localization techniques for Botulinum neurotoxin A injections in clinical routine management of post-stroke spasticity

Abstract

Background: Treatment options for spasticity include intramuscular botulinum neurotoxin A (BoNT-A) injections. Both ultrasound (US) or electromyographic (EMG) guided BoNT-A injections are employed to isolate muscles. To date, most studies have included patients naïve to BoNT-A or following a prolonged wash out phase.

Objective: To determine the impact of US/EMG guided BoNT-A injections on function in outpatients with spasticity receiving an established re-injection regime.

Methods: Thirty patients post-stroke were investigated in a single-blinded, randomized controlled trial using a cross-over design for the EMG and US and a parallel design for the control group. The Modified Ashworth (MAS), Disability Assessment (DAS), Quality of Life (EQ-5D), self-rating scale and Barthel Index were assessed pre- and post-BoNT-A injections of upper limb muscles by a to the injection technique blinded person.

Results: MAS improved in arm, finger and upper limb 4 weeks after BoNT-A treatment. The improvement showed no significant differences between the three injection techniques. Barthel Index, DAS and EQ-5D remained unchanged in all groups.

Conclusions: This pilot study questions the impact of the instrumental guided injection techniques on everyday functionality in a routine clinical setting with established re-injection intervals. Larger trials are warranted with patients who are under long-term treatment on a regular basis.

Keywords: Botulinum neurotoxin; arm spasticity; electromyography; stroke; ultrasound.