Vocal Cord Paralysis, Bilateral

Bilateral vocal cord paralysis is a neurological disorder in which nerve supply to both vocal cords is absent. It most commonly results from injury to the recurrent laryngeal nerves, whether due to thyroid surgery, or blunt or penetrating injury to the neck.

Clinical Findings (Symptoms)

On examination, both vocal cords remain in a midline or paramedian position during both voicing and respiration. The key finding is loss of abduction. Because vocal cords can still vibrate well when closely approximated—even if denervated—voice quality is often surprisingly good.

The primary deficit is airway narrowing. Patients may produce an involuntary inspiratory voice when breathing rapidly or during sleep, and they experience reduced exercise tolerance.

Differential Diagnosis: Bilateral Vocal Cord Fixation

A closely related condition is bilateral vocal cord fixation due to scarring—often the result of prolonged endotracheal intubation. The patient’s history often clarifies the diagnosis:

• Inspiratory phonation and decreased exercise capacity developing immediately after thyroid or goiter surgery suggest bilateral paralysis.
• The same symptoms following long-term intubation suggest posterior commissure scarring.

Diagnostic Evaluation

In addition to history, an intense examination using topical anesthesia in a voice laboratory can differentiate between the two. Findings of granulation tissue, a posterior commissure divot or divots from pressure necrosis, or a synechia between the vocal processes all support an intubation-related injury.

Management

Some patients already have a tracheotomy to bypass the glottic narrowing. The principal surgical alternative is posterior commissuroplasty, which, in the author’s experience with various techniques, provides the best balance between airway enlargement and preservation of voice.

Compared with transverse cordotomy, arytenoidectomy, or lateralization of one vocal cord using the Lichtenberger needle, posterior commissuroplasty tends to achieve a more physiologic airway while degrading voice quality to a lesser degree. The other methods can restore airway effectively, but often at the cost of increased breathiness or loss of vocal strength.