Injection of botulinum toxin into external laryngeal muscles in pediatric laryngeal paralysis

Objectives: I undertook to demonstrate the effect of injecting botulinum toxin type A (BTA) into cricothyroid, sternothyroid, and stemohyoid muscles in cases of bilateral laryngeal paralysis (BLP). Tracheostomy remains the consistently reproducible and accepted method to salvage the airway obstruction in BLP. The bypass, however, acknowledges the current lack of knowledge and consensus on the pathogenesis. Methods: I performed a retrospective chart review of BLP cases treated with BTA in a tertiary care pediatric center. The injections were performed under direct vision through an open transcervical approach. The main outcome measures used were improvement of airway symptoms and endoscopic findings, tracheostomy requirement, and incidence of recovery of function. Results: In total, 24 patients with BLP were identified. Over a 2-year period, 7 patients were treated with BTA. Six patients had congenital idiopathic BLP. One of these had trisomy 7. One patient acquired the paralysis after cardiac surgery. No patients required a tracheostomy, except for the infant with trisomy 7. Six patients recovered function completely, and the seventh recovered it partially (range, 4 weeks to 12 months). Conclusions: Injection of BTA into external laryngeal muscles may be an alternative to tracheostomy in BLP. It is proposed that the toxin relaxes the glottic aperture by paralyzing the cricothyroid and strap muscles and that it may aid in appropriate reinnervation of the larynx via mechanisms beyond the neuromuscular junction.