Ultrasound-guided BoNT-A (botulinum toxin A) injection into the subscapularis for hemiplegic shoulder pain: A randomized, double-blind, placebo-controlled trial

Abstract

BACKGROUND AND PURPOSE: This study aimed to assess the efficacy of an ultrasound-guided lateral approach for BoNT-A (botulinum toxin A) injections into the subscapularis in patients with hemiplegic shoulder pain. METHODS: This single-center trial used a randomized, double-blind, placebo-controlled design. The key inclusion criteria were a visual analogue scale score of ≥4 cm and a modified Ashworth scale score of ≥1+. The patients were randomized to receive either BoNT-A injections or a placebo. The outcomes included the visual analogue scale score, modified Ashworth scale score, pain-free passive range of motion of the hemiplegic shoulder, Fugl-Meyer assessment score for the upper extremities, and Stroke-Specific Quality-of-Life score. RESULTS: A total of 49 hemiplegic shoulder pain patients were screened, and 36 were included. The participants receiving the BoNT-A injection reported a significant decrease in pain (visual analogue scale, -1.39 [95% CI, -2.41 to -0.36]; P=0.002) and spasticity (modified Ashworth scale score for shoulder internal rotation, -0.72 [95% CI, -1.10 to -0.35]; P=0.001; modified Ashworth scale score for shoulder abduction, -0.44 [95% CI, -0.90 to -0.01]; P=0.026) and improved pain-free passive shoulder internal rotation range of motion (14.56 [95% CI, 6.70–21.41]; P<0.001) and quality of life (Stroke-Specific Quality-of-Life upper extremity subscale, P=0.025) compared with those receiving the placebo at the end point. The shoulder abduction range of motion did not significantly improve after the BoNT-A injection at the end point (P=0.127). In addition, the patients in the BoNT-A group showed significant improvements in the visual analogue scale score and shoulder external rotation range of motion at the 12-week follow-up. No injection-related adverse events were observed during or after the interventions in either group. CONCLUSIONS: The ultrasound-guided lateral approach for BoNT-A injections into the subscapularis is a precise and reliable method for reducing pain and spasticity and improving quality of life in stroke survivors with hemiplegic shoulder pain.