Q1. What is vocal cord paralysis?
To understand vocal cord paralysis or vocal cord palsy, we first need to know the location and function of the vocal cords. In a model of a human head, the prominent structure in the mid-neck is the voice box. Inside the box, there is a V-shaped structure known as the vocal cords, situated at the top of the trachea.
This V-shaped structure can open and close, controlling airflow during eating, drinking, and speaking. Breathing is affected when the vocal cords close. Therefore, during breathing, the vocal cords must remain open, allowing air to flow freely. This is how the vocal cords function. The V-shaped muscles control the opening and closing of the vocal cords. If one or both vocal cords cannot move properly, it leads to a condition known as vocal cord paralysis or vocal cord palsy.
Q2. Vocal cord paralysis usually heals on its own.Is treatment essential?
Vocal cord paralysis can resolve on its own in some patients, but for others, the condition may be permanent. The outcome depends on the underlying cause of the vocal cord paralysis or palsy. However, even if there is a possibility of spontaneous recovery, it is not advisable to leave the condition untreated. Vocal cord paralysis can cause inconveniences. Patients may experience breathiness while speaking, a weak voice, difficulty speaking loudly, dizziness from prolonged talking, or inability to work due to speech difficulties.
Nevertheless, speech is not the biggest concern. The primary worry is the potential for swallowing problems. The vocal cords help protect the airway by closing during eating and drinking to prevent food and liquids from entering the trachea. Paralysed vocal cords cannot block food from entering the trachea, leading to choking when eating and drinking. Patients may struggle to cough out foreign objects, as the vocal cords lack the strength to expel them, increasing the risk of pneumonia. This risk is more serious than mere speech difficulties, as it can lead to aspiration pneumonia and pose life-threatening situations. Therefore, treatment for vocal cord paralysis should depend on its cause and impact. If it significantly affects the patient’s life, it should be actively addressed.
Q3. What are the causes of vocal cord paralysis?
Vocal cord paralysis is mainly related to the recurrent laryngeal nerve. This nerve takes a unique looping route, not directly from the brain to the larynx. Instead, it travels down to the chest and back to the larynx, therefore the name recurrent laryngeal nerve.
The brain sends signals to control the vocal cords through this recurrent laryngeal nerve. Its long pathway means that any problem along the way can affect the functioning of the nerve, leading to vocal cord paralysis. The major cause of this paralysis or palsy is surgery. Due to its lengthy route, surgeries on the thyroid, esophagus, or even the lungs and chest cavity can all potentially impact the recurrent laryngeal nerve
When the nerve is affected, patients may experience vocal cord paralysis or palsy. The severity and long-term effects depend on the extent of the damage. If it is only a minor stretch or compression, there is a chance for recovery. However, if the nerve is cut, it can result in permanent vocal cord paralysis. For example, if a patient has thyroid cancer and the tumour is encasing the nerve, it may not be possible to preserve the recurrent laryngeal nerve during surgery. This could result in permanent vocal cord paralysis.
Q4. How is vocal cord paralysis diagnosed?
Confirming vocal cord paralysis is crucial, as other conditions may present similar symptoms. For example, after general anaesthesia, the vocal cords may appear to be paralysed. Intubation can injure vocal cords, causing granulation tissue, hoarseness and symptoms of vocal cord paralysis. Therefore, it is essential to confirm the diagnosis of vocal cord paralysis.
For diagnosis, a laryngoscopy is performed to observe the movement of the vocal cords. If the vocal cords are unable to close, we will examine the width of the gap. Once vocal cord paralysis is confirmed, the next step is to investigate the underlying cause. Since surgery is the major cause of the condition, we will review the patient’s medical history for thyroid, head and neck, or chest surgeries to locate and assess the extent of nerve damage. Since surgery is the major cause of the condition, we will review the patient’s medical history for thyroid, head and neck, or chest surgeries to find out the location and assess the extent of nerve damage.
However, if the patient has no recent surgical history, it is important to check for the possibility of a primary tumour growing near the nerve. A comprehensive CT scan from the skull base to the chest will be arranged. It will look for any tumour compression affecting the entire length of the nerve.
Q5. How to manage vocal cord paralysis?
The management of vocal cord paralysis depends on the patient's symptoms and their severity. If the symptoms are not severe, such as slight hoarseness or minor choking when drinking water, speech therapy sessions will be arranged. The speech therapist will guide the patient on coordinating their breathing to control the functional side of their vocal cords and compensate for the paralysed side. Adding thickening agents to drinks and tilting the head while swallowing can also help minimise choking.
However, if severe vocal cord paralysis makes speaking difficult and causes frequent choking despite thickening agents, surgery may be needed.
The vocal cords normally open and close on both sides. When one side becomes paralysed and cannot function properly, a gap forms, causing air to leak during speaking and water to enter the lungs when drinking. Surgery aims to push the paralysed vocal cord toward the centre, making it easier for the functioning cord to close fully.
There are two types of surgery to bring the vocal cords closer. The first type is an injection using hyaluronic acid, a cosmetic filler, to move the paralysed vocal cord toward the centre. The drawback is that the effects are short-term, lasting three to six months depending on the filler material, and are not permanent. It is suitable for patients whose vocal cords might heal on their own, serving as a temporary solution.
When vocal cords cannot heal on their own, such as after thyroid cancer surgery that cuts the nerves while removing the tumour, and the nerves cannot recover, short-term injectable treatment is not recommended. Instead, open surgery is advised. An incision is made in the neck to insert a plastic material, like silicone or Gore-Tex, to adjust the vocal cords for a permanent outcome.
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