Patients with bilateral paralysis may experience these symptoms, but the possibility of a compromised airway is a more serious threat. The muscles which normally abduct the folds and provide for a patent airway are unable to function. Thus, the folds may remain adducted in the airway and block normal respiration. This may be due to trauma, surgery, viral infection, a tumor pressing on the recurrent laryngeal nerve, or other causes. Occasionally, injury or diseases of the brain, including stroke, result in impaired motion.
Mechanical obstruction can also result in vocal fold motion impairment.
Scar tissue may also accumulate and inhibit vocal fold movement. A small block, usually made of silicone or hydroxylapatite, is secured in the cartilage. This block acts as a shim which pushes the vocal fold medially, helping to improve vocal fold closure. This procedure is relatively quick and painless and is usually performed under local anesthesia. The images below depict the medialization thyroplasty procedure.