[Special Topic on Vocal Cords]The recurrent laryngeal nerve is damaged and cannot be closed freely, and the vocal cords are paralyzed and unable to speak.

Text: Ye Kaixin, “Ming Pao”

(Hong Kong News) When drinking and eating, she often “falls into the wrong place” and “chokes on the water”; when speaking, even if she “screams at the top of her lungs”, she still speaks in a low voice, or even loses her voice.

Problems with eating and vocalization may seem unrelated, but in fact they may be due to the same cause, which is a disease of the vocal cords.

Damage to the nerve cords can lead to paralysis of the vocal cords, which cannot close properly. Unilateral vocal cord paralysis can lead to hoarseness, weakness, and leakage of the voice; if both sides are completely paralyzed, it can lead to voicelessness and even difficulty breathing. Because the vocal cords cannot completely close, water or food particles may fall into the trachea from the gaps in the vocal cords when eating or drinking, causing coughing or even aspiration pneumonia.

Cancer damage due to accidental surgery trauma

The vocal cords are two pieces of muscle tissue located at the entrance to the trachea. When speaking, they close together and vibrate to produce sound. The rest of the time, stay open and relaxed to allow for easy breathing. Why are vocal cords paralyzed?

Tang Zhihao, Honorary Clinical Assistant Professor of the Department of Otolaryngology-Head and Neck Surgery at the Chinese University of Hong Kong, explained: “The vocal cords are innervated by the vagus nerve and are divided into left and right sides. The vagus nerve branches off the recurrent laryngeal nerve below the larynx, and the recurrent laryngeal nerve on one side bypasses the clavicle, and then The recurrent laryngeal nerve on the other side bypasses the clavicle, continues down to the chest and lungs, and then returns to the larynx. Once the recurrent laryngeal nerve is damaged, the vocal cords can be paralyzed and unable to close freely.”

The recurrent laryngeal nerve can be damaged by surgery, accidental trauma, infection, cancer, etc.

Tang Zhihao uses a pair of doors to describe the vocal cords, “This pair of doors opens when we breathe and closes when we make sounds. If only one door can be closed, air will leak when speaking, making the voice sound weak and hoarse; if both doors cannot be closed, , in addition to affecting the voice, in severe cases, because the larynx is uncovered, food debris can easily ‘fall into the wrong place’ when eating, causing aspiration pneumonia.”

The function of the vocal cords is not only to produce sounds, but also to protect the trachea to prevent food, drinks or saliva from entering the trachea and causing choking.

Tang Zhihao pointed out that the throat has a natural safety mechanism when eating. Food in the throat will trigger a swallowing reflex, and the pharyngeal muscles will automatically tighten. The epiglottis will close the trachea and suspend breathing to prevent food or drinks from entering the trachea. If food accidentally enters the trachea, the body will naturally induce a cough to cough up the food.

“However, if the vocal cords cannot be closed normally and there is a problem with the swallowing reflex mechanism, food may easily fall into the wrong rack. This is common in stroke patients. Due to uncoordinated throat function, food may easily fall into the wrong rack when eating, leading to aspiration pneumonia. Severe cases may result in death from suffocation.”

Common sequelae of laryngeal, cervical and thoracic surgery

Vocal cord paralysis is a common sequela of laryngeal and neck surgery. Deng Zhihao explained that surgeries on the neck or near the upper chest may cause damage to the recurrent laryngeal nerve, including surgeries on the thyroid, thoracic blood vessels, gastroesophageal and other parts of the body. Among them, thyroid surgery is the most common. The recurrent laryngeal nerve may be pulled or even severed during the operation, causing permanent damage. In addition, the heat energy released by surgical instruments may also damage the recurrent laryngeal nerve.

“The thyroid gland is located in the front of the neck and throat, close to the trachea and esophagus, and also close to the recurrent laryngeal nerve. It is a site that is more susceptible to injury during thyroid surgery and is also one of the known risks of this surgery.”

Generally speaking, if the recurrent laryngeal nerve is damaged only due to stretch or compression, most cases can be cured after appropriate treatment. The recovery time depends on the degree of damage to the recurrent laryngeal nerve and the patient’s physical condition, ranging from months to years. “If the nerve line is severed, permanent damage will occur and vocal cord function may not be restored.”

Injections or surgery to widen vocal cords

In terms of diagnosis, doctors usually use endoscopy or computer scans to find the cause. Vocal cord paralysis usually resolves on its own within a few months, but if the condition persists, drug injections or surgical intervention may be needed.

Deng Zhihao reminded that with acute vocal cord paralysis, such as viral infection of the recurrent laryngeal nerve, vocal cord function may deteriorate rapidly within a few hours. However, because the symptoms are obvious, patients usually seek medical treatment in a timely manner; on the contrary, if it is chronic vocal cord paralysis, such as laryngeal nerve infection, the vocal cord function may deteriorate rapidly within a few hours. The recurrent nerve is compressed by the tumor and affects the function of the vocal cords. Symptoms may gradually appear within a few days or even a week or two. Therefore, if you find that your voice is hoarse or your wind leakage has not improved after two weeks, you should seek medical advice as soon as possible.

After finding out the cause of vocal cord paralysis, the doctor will decide whether to treat it with drugs or surgery depending on the situation. Taking unilateral vocal cord paralysis as an example, common treatments include injecting hyaluronic acid with a filling effect into the paralyzed vocal cords to adjust the shape and position of the vocal cords. Deng Zhihao explained that the purpose is to widen the vocal cords, so that even if only the other side of the vocal cords can move, it can “close the door” and effectively improve the patient’s speech tone and swallowing function. The benefit of the treatment is immediate results, but because hyaluronic acid is absorbed by the body over time, patients need to receive injections every 3 to 4 months.

“In addition, you can also choose to implant permanent materials in the vocal cords, such as silicone. However, relatively speaking, it takes a long time for patients to adapt and see results.”

Speech therapy to improve voice after surgery

In addition to otolaryngology treatment, speech therapy is often used as auxiliary treatment after vocal cord paralysis.

Luo Jiadong, assistant professor of the Department of Otorhinolaryngology-Head and Neck Surgery and deputy director of the Department of Speech Therapy and speech therapist at the Chinese University of Hong Kong, said that after patients with vocal cord paralysis are diagnosed, they will be referred for speech therapy if necessary, and the treatment mode and time required will be different. Adjust according to treatment reasons and goals.

“Generally speaking, the treatment course lasts from 3 to 6 months and includes about 8 sessions of vocal training, each lasting 45 minutes to 1 hour. The training goal is also divided into two stages: first, let the patient practice and master how to pronounce correctly; The second stage is to strengthen the closure of the patient’s vocal cords to make the voice lines thicker and reduce air leakage.” (For details, see “Vocal Training”)

Luo Jiadong pointed out that in addition to vocal cord paralysis caused by damage to the recurrent laryngeal nerve, many people also have functional voice disorders caused by long-term incorrect vocalization. That is, due to long-term excessive vocalization or incorrect vocalization, the laryngeal muscles are tense. Affecting the voice, these conditions can also be improved through speech therapy.

As long as you keep practicing, your vocal function will definitely improve. It is not difficult to implement and can be practiced anytime and anywhere.

Correct vocalization to protect vocal cords

People with damaged vocal cords should train to pronounce correctly, protect the vocal cords, and increase vocal cord closure.

Resonance vocal exercises

Use your nasal cavity to hum the “M” sound words, such as cat and mom. Start practicing with the single sound first, and then gradually hum short sentences.

The principle of this exercise is to use the smallest force to trigger the closure of the vocal cords through resonant humming and train the vocal cords to close. Using a resonating cavity to speak can reduce the load on the throat muscles and protect the vocal cords.

Semi-obstructed voice line exercises

Hold the drinking tube and squirt water, making a “woo woo” or “bu bu” sound, which will make the vocal cords more relaxed when making sounds, and the flapping amplitude will be smaller, which can not only enhance the closure of the vocal cords, but also reduce the impact and pressure on the vocal cords. .

Excessive vocalization error

Vocal cord calluses and polyps

Vocal cord closure is innervated by the central nervous system, vagus nerve and recurrent laryngeal nerve. In addition to vocal cord paralysis, common vocal cord lesions also include infection and inflammation, nodules, polyps, etc.

1Vocal cord inflammation

Causes: There are two types of inflammation: acute and chronic inflammation. Acute refers to viral infection of the vocal cords, such as upper respiratory tract infection, resulting in vocal cord edema or damage; chronic refers to long-term incorrect vocalization.In addition, gastroesophageal reflux and gastritis are also causes of chronic laryngitis

Symptoms: Hoarse and low voice, or even loss of voice

2Vocal cord paralysis

Causes: Laryngeal trauma, stroke, viral infection, tumor, or complications after laryngeal surgery, etc.

Symptoms: Hoarseness, weakness, wind leakage, and even difficulty breathing

3Vocal nodules

Cause: Chronic vocal cord inflammation caused by long-term overuse or incorrect phonation. Without proper treatment and improvement of phonation, nodules (cocoons) will form on the vocal cords.

Symptoms: Hoarse and low voice, swelling of throat, vocal fatigue, etc.

4polyp

Cause: Long-term excessive vocal use or incorrect phonation, or shouting loudly while the vocal cords are damaged, causing the capillary blood vessels of the vocal cords to rupture and bleed, forming hematomas and, over time, polyps.

Symptoms: Hoarse and low voice

Prevent hoarseness and broken throat

You can learn from Lin Chiling to speak softly

Since the vocal cord muscles are innervated by the recurrent laryngeal nerve, it is also common in clinical practice for patients to have injuries to the recurrent laryngeal nerve due to surgery on the thyroid, esophagus, chest, or cervical spine. When nerve conduction cannot drive the vocal cord muscles, they may also lose their voice.

Korean vocalist Bae Jae-cheol once lost his voice due to thyroid cancer that affected the recurrent laryngeal nerve. Fortunately, he was rejuvenated by a Japanese doctor and regained his beautiful voice.

“When the neuromuscular system is abnormal, it will also affect the vibration of the vocal cords and the quality of the voice.” Laryngologist Xiao Xinchang said that this is common in patients with senile neurological abnormalities or patients suffering from autoimmune diseases such as multiple sclerosis. A small number of patients suffering from lupus erythematosus or hypothyroidism may also have vocal cord tissue edema and hoarseness due to the disease.

“There are also more difficult factors: malignant tumors. For example, when laryngeal cancer grows near the glottis, it may cause hoarseness. At this time, the primary focus is on the diagnosis and treatment of the tumors.”

Hoarseness often recovers on its own

Most hoarseness is reversible. He said that if you ate a big spicy pot the day before, or partyed and yelled all night long, as long as you get a good rest, drink a lot of fluids, don’t drink alcohol, don’t eat spicy food, and slow down your speech, you can help with congestion. The edematous vocal cords return to their original state without the need for medical treatment.

If the vocal cords are inflamed due to gastroesophageal reflux, antacids can be used to treat gastroesophageal reflux; if it is acute edema, steroids can be used to quickly reduce inflammation and swelling of the vocal cords.

“But if there are changes in the structure of the vocal cords or the recurrent laryngeal nerve is ruptured, the hoarseness of the voice is likely to be irreversible.” Xiao Xinchang said.

Therefore, in terms of diagnosis, doctors will first understand the patient’s medical history, then listen to the voice quality to confirm whether there are other symptoms, and finally use laryngeal fiberoptic endoscopy and laryngeal stroboscopy to check the condition of the vocal cords. If there are polyps or nodules, they can be removed surgically; if the vocal cords are paralyzed on one or both sides, endoscopy, imaging examinations, cytology examinations, or further biopsy examinations are required.

When combined with difficulty swallowing or breathing

However, not everyone who develops a hoarse voice seeks medical attention. American scholars once conducted a survey, which showed that about 30% of people have hoarse voices and their quality of life is affected, but only 6% will receive treatment. “Because most people find hoarseness tolerable,” he said.

However, there are some situations where medical treatment must be considered and delaying is not recommended. For example, he said, if the voice is hoarse and a lump is felt on the neck, or combined with difficulty in swallowing, difficulty in breathing, frequent choking, bloodshot saliva, etc., it is likely to be caused by tumors, surgery, or other trauma.

In addition, if the voice is scratchy and there is no sound when speaking hard, “you should also seriously consider seeking medical treatment at this time. It is likely that the vocal cords have polyps, or the vocal cord tissue is eroded and cannot seal tightly.”

Xiao Xinchang once treated an old lady in her 70s for her hoarse voice. In addition to being hoarse, this old lady also often chokes when eating, which makes her often frown when she originally loves chatting with neighbors and friends and eating delicious food. After examination, it was found that the main cause of the hoarseness was lung cancer. The tumor compressed the recurrent laryngeal nerve and caused vocal cord paralysis, resulting in loss of voice.

“The most important thing at that time was the treatment of lung cancer, but the old lady also hoped to restore her voice and regain her quality of life.” Therefore, Xiao Xinchang used thyroid cartilage plastic surgery to increase the tightness of the old lady’s vocal cords, so that she could not only make sounds easily, but also swallow. It is also less likely to choke.

Although the old lady died of lung cancer not long after, the old lady’s daughter told him that the old lady was able to eat and drink happily before she died and regain the happiness in life.

3 No. 3 Warm up and maintain your vocal cords

If you want to take care of your vocal cords and maintain or restore a clear voice, Xiao Xinchang recommends “3 don’ts”: don’t smoke, don’t drink, don’t eat spicy food, warm up your vocal cords, drink more water, and speak softly. Opportunity to maintain a clear voice.

What is vocal cord warm-up? He explained that before a performance, a singer would drink water, take a deep breath, relax the muscles of the body before starting to sing, and then slowly return to normal speed, instead of suddenly singing with an excited voice.

He said, “The best way is to imagine that you are the supermodel Lin Chiling, maintain a soft voice, slow down your speech speed, do not use it all in one breath, and avoid using the strength of the larynx to produce sounds, so that the throat and vocal cords will not be easily tired. ”

Text: Liao Yuning “Yuanqi Network”

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