VOCAL CORD PALSY / IMMOBILITY
Bilateral vocal fold (vocal cord) immobility (BVFI) is a broad term that refers to all forms of reduced or absent movement of the vocal folds.
Bilateral vocal fold (cord) paralysis (BVFP) refers to the neurologic causes of bilateral vocal fold immobility (BVFI) and specifically refers to the reduced or absent function of the vagus nerve or its distal branch, the recurrent laryngeal nerve (RLN).
Vocal fold immobility may also result from mechanical derangement of the laryngeal structures, such as the cricoarytenoid (CA) joint.
What Are the Symptoms?
Both paresis and paralysis of voice box muscles result in:
Voice changes: Hoarseness; breathy voice; extra effort on speaking; excessive air pressure required to produce usual conversational voice; and diplophonia (voice sounds like a gargle).
Assess GRABAS score:
G rade (overall) of hoarseness
A sthenic (weakness or lack of power in voice)
0=normal 1=slight 2=Moderate 3=Extreme
Airway problems: Shortness of breath with exertion, noisy breathing, and ineffective cough.
Swallowing problems: Aspiration symptoms – choking or coughing when swallowing food or drink. Cough with fever.
Also ask about reflux.
1. Unilateral vocal cord paralysis is most common.
1. RLN palsy
Left (75%) , Right (15%) , BL (10%)
2. Superior laryngeal nerve palsy
Combine / complete paralysis
Nuclear : nucleus ambigius
High vagal : combined lesion
Low vagal : RLN palsy
Central neurologic abnormalities
Causes bilateral vocal fold paralysis (BVFP)
1. Arnold-Chiari deformity with meningomyelocele – the most common abnormality.
2. Other CNS insults (eg, infarct, craniotomy, asphyxia)
Malignant : (30% cases)
o Lung carcinoma 50%
o Esophageal carcinoma 20%
o Thyroid 10%
o Penetrating neck or chest trauma.
o Post intubation
o Whiplash injuries
o Multiple Sclerosis
o Myasthenia Gravis
o Wallenberg syndrome (lateral medullary stroke)
o Diabetes Mellitus
o Ortner’s syndrome (left atrial hypertrophy)
o Rheumatoid arthritis – “fixed” cord
o Polyarteritis nodosa
Idiopathic (20-25%): Viral causes ( viral neuritis usually on Right VC)
Vinca alkaloids – in children ungoing chemotherapy for lymphoma
o Vincristine and vinblastine
o Unilateral or bilateral
o Dose related
o Resolves with dose adjustment or cessation
Rosenbach(1880) & Semon (1881)
In all progressive organic lesions, abductor fibres of recurrent laryngeal nerve are more susceptible and thus first to be paralyzed compared to adductor fibres
• WHY ?
1. Nerve fibres supplying abductors are in periphery of RLN
2. Muscle bulk for the abductors is less, more susceptible
3. Phylogenetically, larynx main function is protection, so adductor function are maintained
In progressive vocal cord palsy, vocal cord position will be in median or paramedian first, then later when the adductor fibres are also paralyzed, the vocal cord will be in cadaveric position.
Wegner and Grossman Theory : <popular theory>
• “In the absence of cricoarytenoid joint fixation, an immobile vocal cord in paramedian position has total pure unilateral recurrent nerve paralysis, and an immobile vocal cord in lateral position has a combined paralysis of superior and recurrent nerves (the adductive action of cricothyroid muscle is lost)”
• RLN palsy (intact SLN) – vocal cord in paramedian position (because cricoarythenoid adducts)
• RLN and SLN palsy – vocal cord in cadaveric position
Final position of paralysed VC is not static & determined by :
1. Vocal fold
– Length of VC
– Mass of VC
– Contour of VC
– Synkinesis ( mass movement of all intrinsic muscles due to misinnervation)