Bilateral vocal fold immobility occurs mainly as unilateral or less frequently as bilateral immobility. Numerous metabolic, neurologic, and mechanical conditions can cause bilateral loss of vocal fold abduction. The most important reason is a bilateral vocal fold paralysis related to a lesion of the recurrent laryngeal nerve. Etiologies and key epidemiological numbers are summarized in this chapter. Severity of symptoms of bilateral vocal fold immobility is highly variable depending on the duration of the disease. To decide on the optimal treatment for the individual patient, a sequence of otolaryngological, phoniatric, respiratory, and other functional tests is performed. This will help to find the optimal surgical treatment. The same diagnostic procedures are needed to follow up the patient after surgery to evaluate the efficacy of the applied therapy.
KeywordsVocal fold paralysis Bilateral vocal fold immobility Voice pathology Respiratory test Laryngeal electromyography Diagnostics
For the application of the surface electrode, the investigator has directed the rigid laryngoscope toward the left arytenoid cartilage as well as the entrance to the piriform recess. At first, only the spot for electrically evoked vocal fold adduction could be found, caused by stimulation of the whole recurrent nerve so that the adduction muscles dominate the movement. Switching from 3 Hz (single twitches) to 30 Hz (tetanic contractions) is useful to detect movements but also confirm the main movement. When changing the position of the surface electrode postcricoidally and applying continuous biphasic pulses, a clear opening movement of the left vocal fold can be seen. In general, 2–3 mA should suffice to evoke visible vocal fold abduction (MP4 21287 kb)
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