Which nerve is potentially injured during repair of patent ductus arteriosus?

• A. Vagus
• B. Phrenic
• C. Right recurrent laryngeal
• D. Left recurrent laryngeal

Answer: (D)

During repair of a patent ductus arteriosus, the left recurrent laryngeal nerve is at particular risk because it loops under the aortic arch close to the ligamentum arteriosum, the fibrous remnant of the ductus arteriosus. As the ductus/arotic arch region is dissected and the vessel is ligated, traction or inadvertent injury to this nerve can occur as it travels in the groove between the trachea and esophagus to innervate the laryngeal muscles. When the left recurrent laryngeal nerve is damaged, the left vocal cord can become paralyzed, leading to hoarseness or a breathy voice.

The other nerves are less intimately related to the PDA region. The vagus travels in the superior mediastinum but is not as specifically tethered to the ductus vicinity as the left RLN. The right recurrent laryngeal nerve loops under the right subclavian artery, higher in the chest, making it less at risk in this procedure. The phrenic nerve lies more anteriorly along the pericardium and mainly, if injured, would affect diaphragmatic function rather than vocal cord innervation.