Treatment of shoulder pain in spastic hemiplegia by reducing spasticity of the subscapular muscle: a randomised, double blind, placebo controlled study of botulinum toxin A

Objective: This randomised, double blind, placebo controlled, two parallel group study was conducted to assess the beneficial effect of injection of botulinum toxin A (Dysport) into the subscapularis muscle on shoulder pain in stroke patients with spastic hemiplegia. Methods: A single dose of botulinum toxin A (500 Speywood units) or placebo was injected into the subcapularis muscle. Pain was assessed using a 10 point verbal scale. Subscapularis spasticity was assessed by the change in passive shoulder lateral rotation and abduction. Upper limb spasticity was assessed using the Modified Ashworth Scale for shoulder medial rotators, and elbow, wrist and finger flexors. Assessments were carried out at baseline and at weeks 1, 2 and 4. Results: Twenty patients (10 patients per group), 11 with ischaemic stroke and 9 with haemorrhagic stroke, completed the study. Pain improvement with botulinum toxin A was observed from week 1; score difference from baseline at week 4 was 4 points versus 1 point with placebo (p = 0.025). Lateral rotation was also improved, with a statistically significant difference compared with placebo at week 2 (p = 0.05) and week 4 (p = 0.018). A general improvement in upper limb spasticity was observed; it was significant for finger flexors at week 4 (p = 0.025). Conclusions: Subscapularis injection of botulinum toxin A appears to be of value in the management of shoulder pain in spastic hemiplegic patients. The results confirm the role of spasticity in post-stroke shoulder pain.