Botulinum toxin for the treatment of motor imbalance in obstetrical brachial plexus palsy.

BACKGROUND: Residual muscle imbalance is a common problem affecting obstetrical brachial plexus palsy patients. The goal of this study was to examine the efficacy of botulinum toxin type A (Botox) in improving this muscle imbalance.
METHODS: The authors retrospectively reviewed obstetrical brachial plexus palsy patients treated with Botox for muscle imbalance as an isolated procedure. Outcomes were the change in Active Movement Scale scores from pre-Botox scores to scores at 1 month after Botox and 1 year after Botox.
RESULTS: Twenty-seven patients were included, 19 treated for shoulder imbalance and eight treated for elbow imbalance. Active Movement Scale scores (mean±SD) for shoulder external rotation improved from 0.6±1.0 before Botox to 2.6±2.14 (p<0.01) at 1 month after Botox, and declined to 1.3±1.2 (p<0.01) at 1 year after Botox. Scores for elbow flexion were 3.3±2.1 before Botox, unchanged at 4.4±1.8 (p=0.07) 1 month after Botox, and improved to 5.8±0.5 (p<0.01) at 1 year after Botox. Scores for elbow supination were 2.9±1.7 before Botox and 3.4±1.5 (p=0.2) at 1 month after Botox, and improved to 3.9±2.0 (p<0.01) at 1 year after Botox.
CONCLUSIONS: Botox for shoulder movement imbalance produces improvement in external rotation that is not sufficiently sustained over time to be of clinical benefit. However, Botox for elbow movement imbalance produces a sustained and clinically useful improvement. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.