A patient evaluated for suspected bilateral vocal fold immobility after cardiac surgery has both folds fixed near the paramedian position. Which investigation best distinguishes true neurogenic paralysis from mechanical fixation of the cricoarytenoid joint or posterior glottic scar?
- A High-resolution CT of the neck and chest
- B Flexible laryngoscopy with sniff manoeuvre
- C Laryngeal electromyography ✓
- D Acoustic voice analysis
Correct answer: C. Laryngeal electromyography
Explanation
Laryngeal electromyography records electrical activity in the thyroarytenoid and posterior cricoarytenoid muscles. Denervation potentials indicate true neurogenic paralysis, whereas normal motor unit activity in an immobile cord points to mechanical fixation such as cricoarytenoid joint ankylosis or posterior glottic stenosis, conditions that need endoscopic division rather than reinnervation or medialisation. Imaging and endoscopy locate lesions but cannot prove whether the cord is denervated.
Reference: Scott-Brown's Essential Otorhinolaryngology, 2nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.