After a cardiothoracic surgical procedure, a patient develops left vocal fold paralysis and left pharyngeal paresis. Which is the most likely etiology?

• A. Damage to the left recurrent laryngeal nerve
• B. A left hemispheric stroke
• C. An intraoperative CVA in the right pons
• D. Damage to the right recurrent laryngeal nerve

Answer: (A)

Damage to the left recurrent laryngeal nerve is the most likely cause. During cardiothoracic surgery, the left RLN is at particular risk because it runs in the chest along the tracheoesophageal groove and supplies the intrinsic muscles of the left vocal cord; injury here leads to paralysis of that cord and resulting hoarseness or voice changes on the left. The accompanying left pharyngeal paresis fits with involvement of the vagus nerve or its branches that contribute to the pharyngeal plexus, which can be affected in the same surgical field and produce ipsilateral pharyngeal weakness. In contrast, a stroke affecting the left hemisphere or a brainstem/cerebral event would typically present with additional, more diffuse neurologic signs and not produce this isolated pattern after chest surgery. A lesion to the right recurrent laryngeal nerve would cause right-sided rather than left-sided vocal fold dysfunction.