The vocal folds, also known as the vocal cords, are the part of our larynx that make sound. When we speak, they first close together to seal off the airflow from our lungs. The air pressure against the closed vocal folds causes them to vibrate against one another, making a buzzing sound. This buzz is then shaped by our throat, mouth, and nose into speech and singing and all sorts of other sounds that we make. When we take a breath, the vocal cords open widely to allow air to flow into our lungs. When we cough, the vocal folds close tightly, holding against the pressure that is building up, until they suddenly spring open. The rush of air pushes out whatever is making us cough—mucus, the water we’re choking on, etc. When we swallow, the vocal folds also close tightly, sealing the lungs off as food or liquid passes into the esophagus on the way to the stomach.
All of these functions are governed by two nerves. The main nerve, called the recurrent laryngeal nerve (RLN), travels with a larger nerve called the vagus nerve through the neck, past the larynx, and down into the chest where it leaves the vagus and travels back up to the larynx. This u-turn in direction is why the nerve is called “recurrent.” Interestingly, due to how our vascular system develops when we are a fetus, the right side and the left side go around different structures in the chest before coming back to the larynx. Thus, the right and left recurrent laryngeal nerves are different lengths. The recurrent laryngeal nerve controls 3 muscles that close the vocal cords and also the only muscle that opens the vocal cords. The second nerve is the superior laryngeal nerve (SLN). The SLN travels from the vagus nerve in the neck directly to the larynx, and it controls one muscle that stretches the vocal folds to increase the pitch of the sound. It is also responsible for most of the sensation of the larynx. The sensation is necessary to help us control the timing of our swallowing.
Each side of our larynx contains a small structure called the arytenoid cartilage. The vocal folds and the muscles which control the vocal folds attach to this arytenoid cartilage, which in turn connects to the larger structure of the larynx in a joint much like the knee or finger joints.
Joint injury: sometimes trauma to the neck or the act of putting a breathing tube in the airway can dislocate the arytenoid joint which prevents the vocal fold from moving, even if the nerves and muscles are working normally.
Nerve damage: If the RLN stops working, the voice muscles don’t contract, and the vocal fold does not move. If the nerve on one side stops working, then one vocal fold does not move. This is called unilateral (one-sided) vocal fold paralysis. Bilateral paralysis is when both sides stop working and is much less common. For this article, we will just discuss one-sided problems. The RLN can be injured by a virus, during surgery, or as a result of a cancer in the neck or chest in the vicinity of the nerve. Sometimes, just having a breathing tube placed for surgery can cause the nerve to stop working, even if the arytenoid joint is fine.
When one arytenoid joint is injured or one RLN stops working, the vocal fold on that side does not move, making coughing, swallowing, and talking more difficult. The cough is weak, the voice is breathy, and swallowing is difficult—especially liquids. Sometimes people feel like they run out of breath when they talk. This is because the vocal folds can’t close tightly, and air slips through too fast, causing the person to take more breaths than normal to get the words out. Alternatively, because the vocal fold cannot open fully, some patients feel trouble breathing when they exert themselves, like climbing steps, taking a brisk walk, or even doing chores.
An experienced clinician can often diagnose one-sided vocal fold immobility just by hearing the patient talk. We first listen to the patient describe the symptoms and review the other related history. We then perform a complete head and neck exam to look for causes and other neurologic problems. Next, we look at the larynx using flexible laryngoscopy. In this exam, the nose is numbed up and decongested with a nasal spray. Then a thin, flexible camera is passed through the nose and into the back of the throat to look at the larynx. From here, the patient talks, laughs, swallows, and even sings. With the camera, we can see what is strong, what is weak, and if there are any other concerning findings in and around the larynx. This “scope” exam is crucial. It is the primary way we diagnose exactly what’s going on. Nearly everyone (including kids) tolerates the exam just fine, and most people who are nervous say, “That’s it?” at the end of the test.
Once we confirm that the vocal fold is not moving, unless it is clearly related to a surgery where we know the nerve could be injured, we order a CT scan of the neck and upper chest to look for cancers or other things that can put pressure on the nerve and make it stop working.
Another test that we may do is electromyography (aka an EMG) of the larynx. We insert small needles into the muscles that aren’t moving to help us know if the nerve is working or not.
Vocal paralysis can be treated easily and quickly to help patients get their voice and swallowing back. After we confirm why the vocal fold is not moving, we make a treatment plan. Two critical parts are required.
Speech therapy: First, our patients start physical therapy with our voice therapists. Voice therapy is performed by Speech Language Pathologists who are trained in helping patients with voice problems. Many times, therapy can help people swallow better, breathe better, and speak better.
Vocal fold repositioning: Second, we reposition the weak vocal fold so that the good one can reach it to close firmly. There are two overall categories of how a vocal fold can be repositioned. Injections: Most patients with a new vocal fold paralysis are offered an injection into the weak vocal fold. The injection improves symptoms for a time, allowing damaged nerves time to recover. A gel is injected into the vocal fold either in the office (most patients) or in the operating room. The gel pushes the vocal fold toward the middle where the opposite vocal fold can then meet it. The gel lasts 2-4 months in most cases. When we do this procedure in the office, we use a camera in the nose just like when the problem was diagnosed. After making the skin and throat numb, a thin needle is inserted through the neck and into the vocal fold, and the gel is injected. When we do this procedure in the operating room, after going to sleep, a laryngoscope (like a specially-shaped pipe) is placed through the mouth and down to the vocal folds. A long needle is used through the laryngoscope to inject the gel. Fat can also be collected from the abdomen and injected into the vocal fold. We sometimes repeat this process while we wait for the nerve to recover. Surgery: For patients whose vocal fold is not expected to recover, such as in cases where the RLN had to be removed because of cancer and those who have had an immobile vocal fold for more than 9 months, we do a permanent procedure. We make an incision over the Adam’s apple, create a hole through the cartilage of the larynx, and place an implant to push the vocal fold over. Sometimes, we adjust the position of the arytenoid cartilage as well to improve the outcome. The implant can be made of a soft plastic wedge that is carved to be a custom size during surgery or a Gore-Tex ribbon that is layered into the larynx. The patient is awake during surgery so that we can hear how the voice sounds and adjust the implant to maximize the results of the surgery.
Recovery from both procedures is usually not very difficult, and patients are back to normal life within a couple of days. The voice improves over several weeks as swelling goes down, and voice therapy after surgery is important as well.
We are here for you
If you or someone you know has vocal fold immobility or hoarseness that won’t go away after 2-3 weeks, it is critical that an experienced doctor looks at the larynx to diagnose the problem. Early diagnosis and proper treatment are incredibly important to helping people to find their voice again. Reach out to your doctor, your local ENT surgeon, or come see us at the Greenville Voice Center at Greenville ENT Associates.<< Read More Articles