The right and left recurrent laryngeal nerves control the motion of the vocal cords. Damage to one or both of these nerves leads to vocal cord paralysis. Causes of injury to the nerve include inadvertent damage from neck surgery such as thyroidectomy, carotid endarterectomy or others, complications from having an edotrachela (breathing) tube, trauma to the neck or chest, tumors involving the base of the skull, neck, or chest, and viral infections.

If the cause of the paralysis is not apparent, observation, sometimes with speech therapy, may be recommended for up to a year to allow for spontaneous resolution of the paralysis and compensation from the opposite side. Surgical intervention is appropriate if the paralysis is deemed irreversible and the symptoms of hoarseness and/or choking are causing significant problems. This can take the form of injecting the paralyzed vocal cord with temporary or permanent fillers to bulk up the cord (vocal cord injection) or repositioning the vocal cord with an implant (thyroplasty). A tracheotomy may be indicated if there are serious breathing problems.