Ultrasound of the vocal cords in infants

Vocal cord paralysis is a common cause of respiratory and feeding problems in the pediatric population. While the causes of vocal cord paralysis are multiple, iatrogenic injury of the recurrent laryngeal nerve after cardiovascular surgery is the most frequent cause. Vocal cord paralysis increases the risk of swallowing dysfunction, tracheal aspiration and pneumonia. It also increases the need for nasoenteric feeds and gastrostomy tube placement. Flexible nasopharyngolaryngoscopy is considered the gold standard for diagnosing vocal cord paralysis, but it has significant drawbacks: it is uncomfortable, it can trigger a cardiovascular event in children with unstable cardiovascular status, it can be challenging to perform, and it can be difficult to interpret. Laryngeal US has become a popular imaging modality to evaluate the function of the vocal cords. Laryngeal US is well-tolerated, easy to perform, simple to interpret and has a lower physiological impact compared to flexible nasopharyngolaryngoscopy. Laryngeal US is an accurate and low-cost diagnostic test for vocal cord paralysis. In this review, we describe the anatomy of the larynx and recurrent laryngeal nerve; the causes, symptoms and pathophysiology of vocal cord paralysis; laryngeal US technique; diagnostic criteria for vocal cord paralysis; and a reporting system.