Botulinum toxin as an adjunct to motor learning therapy and surgery for obstetrical brachial plexus injury

Area of Science:

• Pediatric Neurology
• Rehabilitation Medicine
• Movement Science

Background:

• Obstetrical brachial plexus injury disrupts neural pathways, impairing infant motor learning.
• Suboptimal function can persist post-reinnervation due to antagonist muscle overactivity.
• Targeted interventions are needed to enhance functional recovery in affected infants.

Observation:

• A case series involved eight infants (5 female, 3 male; mean age 12.5 months) with obstetrical brachial plexus injury and evidence of reinnervation.
• BTX-A was injected into specific antagonist muscles (triceps, pectoralis major, latissimus dorsi) to reduce overactivity.
• Improvements in active movement and functional abilities were observed post-injection.

Findings:

• All parents reported functional improvements after BTX-A injection.
• Significant improvements in Active Movement Scale scores were noted at 1 and 4 months post-injection (p=0.014, p=0.022).
• BTX-A facilitated motor learning by enabling voluntary antagonist muscle relaxation and promoting reinnervated muscle activity.

Implications:

• BTX-A shows promise as an early intervention to improve functional outcomes in infants with obstetrical brachial plexus injury.
• This approach may enhance motor relearning by modulating muscle synergies.
• Further research is warranted to explore long-term efficacy and optimal treatment protocols.