Left Vocal Cord Paralysis: Etiology, Evaluation, and Management

Unilateral vocal fold paralysis (UVFP) causes breathy voice, weak cough, aspiration risk. Left side more common (longer recurrent laryngeal nerve course).

Causes (Left RLN Pathway: Mediastinum → Aortic Arch → Tracheoesophageal Groove)

1. Thoracic malignancy: Lung cancer, esophageal cancer, mediastinal lymphoma (most common neoplastic).
2. Cardiovascular: Aortic aneurysm, post-cardiac surgery (CABG, valve), PDA ligation.
3. Thyroid: Cancer, large goiter, post-thyroidectomy (10–15% temporary, 1–2% permanent).
4. Neurologic: Stroke (lateral medulla), MS, ALS.
5. Trauma: Intubation, cervical spine injury, blunt neck trauma.
6. Idiopathic: 20–30% (likely viral neuritis).

Evaluation

• Flexible laryngoscopy (confirms paralysis, position).
• CT neck/chest (entire RLN course) – mandatory for left UVFP.
• Labs: TSH, autoantibodies, ACE (sarcoid).
• EMG laryngeal (prognosticate recovery).

Management

• Observation (6–12 mo): 60–70% idiopathic recover.
• Voice therapy: Resonant voice, breath support.
• Medialization: Injection laryngoplasty (gel, CaHA) → temporary; thyroplasty (Gortex, silastic) → permanent.
• Reinnervation: Ansal-RLN anastomosis (long-term tone).
• Tracheostomy: If bilateral or severe aspiration.