There can be genetic bases for familial recurrent nerve palsy, which can start in young children or is not noticed until middle age. In some cases the gene producing a motor protein that moves molecules from the end of the nerve back up to the nucleus may be mutated. There’s not the normal transport of molecules to keep the nerve healthy. This type of nerve palsy usually doesn’t occur until people reach their 40s or 50s, but in some families where this trait is dominant it can affect very young children and even infants who have vocal fold palsy at birth. In those cases the infant often must have a tracheotomy to open up their windpipe.
What is the typical course of treatment?
If the paralysis is the result of a surgical procedure that injures the nerve, the patient should be seen by an otolaryngologist, who does surgery on the vocal folds. The otolaryngologist will decide what is the best course for treatment. If the patient doesn’t have any problems swallowing, the patient may use voice therapy with a speech pathologist to learn to improve their voice while the nerve regenerates. This is done to keep the patient from developing some sort of abnormal compensation as the nerve heals.
If the person has severe swallowing problems, an otolaryngologist may inject substances into the vocal fold. This will bulk up the fold that’s paralyzed and move it more to the center [of the throat]. That will usually last six months or so, just to get the patient through the time while the nerve is growing back. If the nerve doesn’t grow back, the otolaryngologist may do a procedure called a thyroplasty, where they put a wedge into the paralyzed side to move the fold permanently more towards the center of the throat. That helps with the voice and swallowing. It may not make it normal but it will significantly improve. Another approach is to suture a fold towards the center of the larynx or to suture another nerve to the end of the damaged nerve, although that’s done less frequently than a thyroplasty.
What new technologies in development might better help people suffering from vocal fold paralysis?
David Zealear at Vanderbilt University has been working for a couple of decades on electrical stimulators that can be implanted into the muscles in the back of the larynx for people who have bilateral vocal fold paralysis to help them breathe. [Zealear and his team are developing an implantable laryngeal pacemaker that could restore normal breathing through the mouth without injuring the vocal folds, a project unrelated to Leonessa’s electrical stimulation work.] The pacemaker can be programmed so that the vocal folds open for each breathing cycle. If there’s damage to the muscle, however, a stimulator would not work.
If you don’t have an intermittent stimulator like what Zealear is working on, there is a permanent surgical procedure where you pull one of the vocal folds to one side to provide an airway. This, of course, would affect your ability to speak.
How common is vocal fold paralysis?
Left-side paralysis is more common than paralysis on the right side, but it’s very rare that someone would have paralysis on both sides. The last I heard was 200 new cases per year of bilateral vocal fold paralysis.
What are the chances that a person will recover from this condition?
Often, when there’s an injury to the recurrent laryngeal nerve, it will spontaneously “re-enervate,” meaning the nerves will grow back. That depends upon how high up [the throat] the lesion is. If the lesion is up to the point where it emits from the skull, then you’re going to have a very long pathway for that nerve to grow back. In some cases the nerve can also grow back to the wrong muscle. If the injury is close to where the nerve goes into the larynx, then your chances of re-enervation are pretty high. Usually, within three months you’ll see some signs of re-enervation. Within nine to 12 months final re-enervation can be completed.