Vocal Fold Paralysis

Vocal fold paralysis is impaired or absent vocal fold mobility due to lesions affecting the vagus nerve (CN X), its branches (recurrent laryngeal nerve RLN supplying all intrinsic laryngeal muscles except cricothyroid; superior laryngeal nerve external branch supplying cricothyroid for tension), or muscle. RLN takes a long course (left longer than right, looping under aortic arch; right looping under right subclavian artery), making it vulnerable to injury throughout neck, mediastinum, thorax. Unilateral VFP is more common; bilateral VFP is potentially life-threatening due to airway compromise.

Etiology of unilateral VFP: iatrogenic (thyroid surgery 30-40%, especially with malignant disease, reoperation, large goiter; cardiothoracic surgery; cervical spine surgery anterior approach; carotid endarterectomy; esophageal surgery; lung resection), malignancy (lung cancer especially upper lobe, esophageal, thyroid, mediastinal), idiopathic (10-25%, viral neuritis suspected), cardiac (Ortner syndrome from left atrial enlargement), aortic aneurysm, neurological (CVA brainstem, multiple sclerosis, ALS), traumatic (intubation, neck trauma), inflammatory (thyroiditis, sarcoidosis), and infectious (viral, syphilis, Lyme, tuberculosis). Bilateral VFP: thyroid surgery (most common), cardiothoracic surgery, intubation trauma, neurological disease (ALS, multiple system atrophy, brainstem stroke, neuromuscular junction disorders), idiopathic, and post-radiation.

Evaluation: history (recent surgery, trauma, malignancy, neurological symptoms, dysphagia, aspiration, weight loss), laryngoscopy (flexible/rigid, stroboscopy assesses position fixed in median, paramedian, intermediate, lateral; mucosal wave usually absent on paralyzed side), laryngeal EMG (prognostic for recovery, presence of voluntary motor unit action potentials by 6 months suggests recovery, complete electrical silence with no fibrillations after 6 months suggests poor recovery), imaging of entire RLN course (CT neck/chest with contrast for unilateral, brain MRI if vagal high lesion suspected, ultrasound thyroid, esophagoscopy for esophageal lesions, modified barium swallow for aspiration). Workup for idiopathic: ESR, CRP, RF, ANA, ANCA, ACE, RPR, Lyme, HIV, treponemal antibodies. Treatment of unilateral VFP: voice therapy with SLP (vocal exercises to recruit unaffected fold, postural adjustments, swallow techniques), injection laryngoplasty (initial temporary with collagen, hyaluronic acid for spontaneous recovery monitoring 6-12 months; permanent with calcium hydroxylapatite or autologous fat for confirmed permanent paralysis; performed transorally or percutaneous), medialization thyroplasty (type I, Isshiki, gold standard for permanent unilateral VFP, GORE-TEX or silicone implant), arytenoid adduction (combined with thyroplasty for posterior glottic gap, adducts vocal process), nonselective RLN reinnervation (ansa cervicalis-RLN), selective laryngeal reinnervation, laryngeal pacing (research). Bilateral VFP: tracheostomy for severe airway obstruction, partial arytenoidectomy (laser CO2, transverse cordotomy), arytenoidpexy, transverse posterior cordotomy, posterior cricoidotomy with cartilage graft, RLN reinnervation, laryngeal pacing (potentially restores movement). Aspiration management: thickened liquids, swallow therapy, gastrostomy if severe.