Vocal Fold Paralysis
What Is Vocal Fold Paralysis?
When we breathe, our vocal folds open into a V-shape to allow air in. When we want to make a noise, the vocal folds come together and close.
The nerve that controls motion to the vocal folds is called cranial nerve X (also known as the vagus nerve). You can think of nerves like the electrical wiring to the voice box. The branch that controls the opening and closing of the vocal folds is called the recurrent laryngeal nerve. It has a very long, circuitous route: starting in the brain, it goes through the neck into the chest where it wraps around some large blood vessels and goes back up into the neck, hence, recurrent.
If the recurrent laryngeal nerve isn't working, the vocal fold that it innervates stops moving.
If one nerve is not working well (unilateral vocal fold paralysis) it can be hard for the vocal folds to close (adduct) so that you can make a voice. The voice will often be very weak and breathy. It can also be hard to control the rate at which you exhale your breath, making you feel out of breath when you talk.
If both nerves are not working well (bilateral vocal fold paralysis), it can be hard for the vocal folds to open enough (abduct) to allow you to get enough air.
What Are the Symptoms of Vocal Fold Paralysis?
- You may have a breathy voice.
- You may have a weak voice.
- You may have difficulty raising the volume of your voice.
- Drinking liquids may make you choke and sputter.
- You may run out of air quickly when you talk or exercise.
- You may have noisy breathing.
- You may feel short of breath.
What Can Cause Vocal Fold Paralysis?
- Surgery in the neck or chest such as thyroidectomy, carotid endarterectomy, anterior cervical disk fusion, or aortic arch surgery
- Cancers such as laryngeal, lung or breast
- Idiopathy (we don't know why)
How Can You Diagnose Vocal Fold Paralysis?
Vocal fold paralysis is diagnosed with laryngoscopy. Electromyography can also be helpful. Electromyography is a procedure in which a special needle is inserted into the muscles of the larynx (voice box) and the electrical signals from the nerve are measured. If the nerve is not working (and the vocal fold is thus paralyzed), the electrical signals will be altered.
How Do You Treat Unilateral (One-Sided) Vocal Fold Paralysis?
There are several different options, most of which focus on pushing the paralyzed vocal fold to the middle of the voice box so that the working vocal fold can close against it.
In this procedure a material is injected into the vocal fold to bulk it up and allow the vocal folds to close. This can be done in two different ways. One way is with the patient awake with a flexible telescope in the nose and the injection needle passed through the neck. The other way is with the patient asleep and the approach is through the mouth. Many different types of materials are used for injection.
Medialization (or Type 1) Thyroplasty
This is a surgery in which a material is implanted just to the side of the paralyzed vocal fold to push it over. It is performed with the patient lightly sedated and with numbing medicine. A small incision is made on the side of the neck and a window is taken out of the thyroid cartilage (the framework of the larynx). Various materials, such as silastic and gortex, can be implanted through this window. They act like a wedge to push the vocal fold over. This operation is often combined with another procedure called an arytenoid adduction, which can improve the vocal folds closure. Throughout the case the surgeon may ask the patient speak, allowing the surgeon to know how large to make the implant.
In this surgery, the recurrent laryngeal nerve going to the paralyzed vocal fold is cut and then reconnected to another working nerve, typically to the ansa cervicalis, which innervates some of the small muscles of the neck. Over the course of 9 to 12 months, the nerves from the ansa cervicalis will grow into the remainder of the recurrent laryngeal nerve. This can result in improved vocal fold tone (tension, so it is not floppy) and position (closer to the middle so that the working vocal fold can touch). However, reinnervation does not restore movement to the paralyzed vocal fold.
How Do You Treat Bilateral (Both Sides) Vocal Fold Paralysis?
The vocal folds are the gateway to the windpipe and lungs. They also have two functions. The first is to open to allow air into the lungs. The second is to close, allowing exhaled air to pass through them, causing them to vibrate and make sound. When both vocal folds are not moving properly, they are unable to do both functions. Frequently the patient and otolaryngologist must choose to sacrifice voice in order to have a larger airway. This can be done with a procedure called a cordotomy wherein the back portion of one or both focal folds are removed to make more room for air movement. The voice typically will be weak and breathy afterwards.
Alternatively the patient and otolaryngologist may choose a tracheostomy, a tube placed in the neck below the vocal folds, which allows easy air movement through the neck into the lungs. A speaking valve can be fitted on the tracheostomy to allow the patient to speak with his or her own voice.
A patient who has difficulty breathing may need a tracheostomy regardless.