How should I evaluate and manage a patient with a unilateral lateralized vocal cord?

Evaluation and Management of Unilateral Vocal Cord Paralysis

For a patient with unilateral vocal cord paralysis, perform laryngoscopy immediately to confirm the diagnosis, then obtain contrast-enhanced CT of the neck extending through the aortopulmonary window to identify the underlying cause, followed by early voice therapy and consideration of injection laryngoplasty within 6 months if symptoms persist. 1, 2

Initial Diagnostic Evaluation

Laryngoscopy - The Essential First Step

• Laryngoscopy is mandatory and must be performed before any imaging studies to visualize the vocal cord position and confirm paralysis 3, 1, 2
• Direct visualization distinguishes true vocal cord paralysis from other causes of hoarseness and identifies the position of the paralyzed cord 1
• This examination should be performed in all patients with persistent voice changes lasting beyond acute illness 1

Imaging to Identify the Cause

After confirming vocal cord paralysis on laryngoscopy, obtain contrast-enhanced CT of the neck extending through the aortopulmonary window to evaluate the entire course of the recurrent laryngeal nerve from skull base to thorax 3, 2

• This imaging protocol allows assessment of the jugular foramen, the full extracranial course of the vagus nerve, and the complete path of the recurrent laryngeal nerve 3
• The left recurrent laryngeal nerve loops around the aortic arch beneath the ligamentum arteriosum, while the right loops around the subclavian artery, requiring thoracic imaging 3
• CT has demonstrated diagnostic yields ranging from 23.5% to 47.5% for identifying causes of vocal cord paralysis, with higher yields (40%) in patients over 65 years 3
• Do not obtain CT or MRI before visualizing the larynx, as this represents unnecessary cost and potential harm without established benefit 3

Additional Diagnostic Considerations

• MRI of the brain and skull base with gadolinium is preferred when central lesions or skull base pathology is suspected, particularly if additional lower cranial nerve palsies are present 3
• Laryngeal electromyography (LEMG) can help distinguish neurological paralysis from traumatic arytenoid dislocation, though its routine use is not mandated 2

Common Etiologies to Consider

The diagnostic workup should focus on these most frequent causes:

• Thyroid surgery is the most common cause, occurring in up to 2.1% of thyroidectomy patients, with rates up to 30% in revision thyroid surgery 3, 1
• Other surgical causes include anterior cervical spine surgery, cardiac surgery, and carotid endarterectomy, with hoarseness occurring in up to 50% immediately post-surgery 1
• Thoracic causes such as lung cancer, mediastinal masses, and aortic aneurysm are common, particularly affecting the left recurrent laryngeal nerve 3
• Neurologic diseases including stroke, Parkinson's disease, and other central nervous system pathology 1
• Idiopathic causes account for a significant proportion when initial workup is negative 3

Management Strategy

Voice Therapy - The Primary Initial Treatment

Begin voice therapy immediately as the first-line treatment for unilateral vocal cord paralysis 1, 2, 4

• Voice therapy should consist of 1-2 sessions per week for 4-8 weeks with a speech-language pathologist 2
• Early initiation of voice therapy (within days to 2 weeks of symptom onset) produces superior outcomes compared to delayed therapy started 1-1.5 months after onset 4
• Goals include eliminating harmful vocal behaviors, developing healthy vocal techniques, and helping patients adapt to altered laryngeal physiology 2
• Voice therapy can provide temporary or permanent improvement through exercises and compensation strategies 1

Injection Laryngoplasty - Early Intervention Option

For patients with persistent symptoms despite voice therapy, consider injection laryngoplasty within the first 6 months 1, 2

• Early intervention with injection laryngoplasty (within 6 months) decreases the need for more invasive therapies long-term 2
• This procedure restores vocal cord position and volume, and can be performed in the office under topical anesthesia or in the operating room 2
• Injection laryngoplasty serves as a temporary solution while awaiting potential spontaneous recovery 1

Additional Surgical Options

For patients requiring more definitive treatment:

• Framework procedures (medialization thyroplasty) provide longer-lasting results than injection 1
• Reinnervation surgery may be considered in select cases 1
• These options are typically reserved for patients with no recovery after 6-12 months or those with poor response to less invasive interventions 1

Critical Clinical Considerations

Aspiration Risk Assessment

• Systematically evaluate for aspiration, as it occurs more frequently than commonly recognized in unilateral vocal cord paralysis 5
• Up to 56% of patients with unilateral vocal fold immobility experience dysphagia, with observed aspiration in 44% 3
• Silent aspiration can occur, requiring formal swallowing evaluation with fiberoptic laryngoscopy or videofluoroscopy, particularly after thoracic surgery 5

Quality of Life Impact

• Dysphonia affects up to 80% of individuals with unilateral vocal fold immobility after thyroid surgery 3
• Voice changes significantly impact work capacity, with patients requiring more days off or job modifications 3, 2
• Breathing difficulties during daily activities occur in 75% of patients with unilateral vocal fold immobility 3

Prognosis and Patient Counseling

• Inform patients that vocal cord paralysis can resolve spontaneously within one year, but complete recovery is not guaranteed 2
• Early identification and intervention allow patients to return more quickly to normal social and occupational activities 2
• The decision to proceed with permanent surgical intervention should generally be delayed until at least 6-12 months to allow for potential spontaneous recovery 1

Common Pitfalls to Avoid

• Never obtain imaging before performing laryngoscopy - this violates evidence-based practice and increases costs without benefit 3
• Do not delay voice therapy while waiting to see if spontaneous recovery occurs - early therapy improves outcomes 4
• Avoid assuming unilateral paralysis does not cause aspiration - systematic evaluation is necessary 5
• Do not rush to permanent surgical procedures before allowing adequate time for potential recovery 1, 2