Laryngeal Photos: Paralysis: Bilateral Paralysis

Initially after an injury

Bilateral paralysis shows up in different ways on examination depending on when the injury occurred. Initially both vocal cords will typically be ABducted or apart. There will be little or no voicing, perhaps only whispering. Choking may be a severe problem and drinking without coughing may be impossible.

Breathing will be fine, that is to say, no noise or restriction in breathing, though it is quite common to feel “out of breath”. The vocal cords actually typically close partway during expiration (breathing out) to provide some resistance and keep the lungs full of air. When the lungs do not stay full with air, the alveoli in the lungs collapse. Like a balloon that is completely deflated, it is hard to get the alveoli open again. A partially inflated balloon is easier to fill. A lung that is partially filled with air is easier to add air to. The ability to close the vocal cords keeps the lungs partially inflated when breathing out.

As time goes by, if the nerve to the vocal cords is intact (not cut) the vocal cords will regain innervation or a nerve supply. Usually though, the vocal cords will regain normal movement opening and closing, they will just gradually regain muscle tone. This muscle tone usually places the vocal cords very close together. So, several months after an injury, the voice will begin to return and choking will be much less of a problem. However now breathing usually becomes limited in some way, possibly severely so. Usually breathing is ok at rest, but noisy and difficult to get much air with any significant activity. The nerve when it reconnects to the vocal cords may even cause a paradoxical motion. Because in the uninjured person, a single nerve trunk provides signals for both the opening and the closing muscles of the voicebox, the wires within the nerve trunk often get crossed on healing and there is thus a very poorly controlled motion, even though some of the nerve fibers are again hooked up.

Bilateral paralysis is almost always the result of an iatrogenic injury - meaning that it is caused inadvertently by a physician. Thyroid surgery or parathyroid surgery which are often performed on both sides of the neck can injure both recurrent laryngeal nerves. Also, after a tube has been in the windpipe to breath (an intubation such as for anesthesia), the inflated cuff of the ballon on the end of the tube will uncommonly injure both recurrent laryngeal nerves where they enter the inside of the larynx.

Bilateral vocal cord fixation is quite often confused with bilateral paralysis. It is extremely important to differentiate between the two as early surgical intervention is more successful with fixation. The typical wait before doing any intervention with a bilateral paralysis is over a year. During that time a bilateral fixation will only become more permanent and more problematic to repair in the future. A history of airway obstruction shortly after an extubation (weeks to a month or two) is more consistent with scarring and fixation.

Anyone with trouble speaking or breathing after an extubation should have a thorough, extended laryngeal exam as soon as possible. An EMG (electromyogram) can be helpful, but the close exam is more important.

More than a year after an injury

Post surgery