What is Unilateral Vocal Cord Paralysis?
Unilateral vocal cord paralysis (UVCP) is a condition often seen by ear, nose, and throat (otolaryngology) doctors. People with this condition experience symptoms like voice changes (dysphonia), difficulty in breathing, and trouble swallowing. This condition happens as a result of damage to a particular nerve in the throat (recurrent laryngeal nerve) due to reasons such as cancers, physical injuries, or surgeries.
Diagnosing UVCP involves a thorough review of the individual’s medical history, a detailed physical exam, and possibly additional medical tests, performed by an experienced ear, nose, and throat doctor. The goal is to find out the root cause of the problem. In many cases, the doctor can restore the patient’s voice through a variety of surgical and non-surgical treatments.
What Causes Unilateral Vocal Cord Paralysis?
The reasons behind UVCP, or unexplained vocal cord paralysis, can differ based on location and time. From 1985 to 1995, in North America, cancer was the most frequent cause. From 1996 to 2005, the main cause shifted to injuries from surgery, with most non-thyroid operations leading to more injuries than thyroid surgeries. However, in Italy, the leading causes were thyroid surgeries, unexplained paralysis, and chest surgeries.
Cancer remains the most alarming cause of UVCP, especially lung and laryngeal (vocal cord) cancer. Cancer of the thyroid and the central nervous system (brain and spinal cord) are less common.
Injuries caused during operations, specifically thyroid surgeries, are a common cause of UVCP. This is usually due to an unusual layout of the recurrent laryngeal nerve, a nerve that controls the voice box. Doctors often use nerve stimulators during surgery to avoid any harm but their effectiveness is yet to be validated. Other surgeries including spine surgery, esophagus removal or chest surgery can also injure this nerve. Sometimes, surgeries involving a breathing tube can also put pressure on the nerve leading to paralysis.
Traumatic UVCP is also common, but quite hard to understand. The proposed causes include direct damage to the recurrent laryngeal nerve or dislocation of the vocal cord structure called the arytenoid.
There are also several less common causes of UVCP that include neurological issues (like stroke or disorders like myasthenia gravis and multiple sclerosis), inflammatory illnesses (like sarcoidosis and lupus), and infectious diseases (like Varicella Zoster and Lyme disease).
A common but poorly understood type of UVCP is idiopathic paralysis, thought to be caused by viral or inflammatory diseases. However, this diagnosis is usually a last resort when all other potential causes have been ruled out.
Risk Factors and Frequency for Unilateral Vocal Cord Paralysis
The causes of UVCP (Unilateral Vocal Cord Paralysis) and its diagnosis are not straightforward. No firm data has been published about how often it occurs in the general population. When comparing patient information such as age, gender, or how long they’ve had symptoms, there’s no significant difference between those with neurological causes and those with other causes. However, people with a history of cancer or thyroid disease are significantly more likely to be in the neurological group.
Signs and Symptoms of Unilateral Vocal Cord Paralysis
Unilateral vocal cord paralysis, abbreviated as UVCP, can lead to a variety of symptoms. Most people with this condition will experience a sudden change in voice, which may sound weak or “breathy”. Another common symptom is difficulty with swallowing, known as dysphagia, which can sometimes cause food to come back up, a process known as regurgitation. Many people may also have difficulty exercising due to getting out of breath, even though their lungs are working as they should.
Each individual’s personal medical history, lifestyle, and even travel history can suggest different causes for the condition. For instance, symptoms like pain when swallowing, swollen neck lymph nodes, night sweats, ear pain, weight loss, and coughing up blood can be warning signs of head and neck cancer. Similarly, a history of lung or heart disease, a history of smoking or drinking alcohol, exposure to job-related risks, a history of intravenous drug use, or recent travel to foreign countries can point to less common causes.
When a patient with these symptoms sees a doctor, they will be given a thorough ear, nose and throat examination. This will often involve carefully examining the neck and looking inside the throat and voice box using a flexible tool called a nasal endoscope. The doctor will also evaluate the quality of the patient’s voice, often using a scale known as the GRBAS scale, which stands for Grade, Roughness, Breathlessness, Aesthenia, Strain. Typically, those with UVCP have worse scores on this scale.
Testing for Unilateral Vocal Cord Paralysis
If you’re suspected of having a lung condition, your doctor might suggest a chest X-ray as a preliminary screening tool. However, this test is not able to pick up smaller abnormalities as decisively as cross-sectional imaging techniques. For thorough imaging, a CT scan (Computed Tomography scan) is typically preferred as it can image your body from the base of your skull down to your diaphragm. While a CT scan is effective at mapping out diseases in your body, it has some limitations like exposing you to low amounts of radiation, being costly, and sometimes having a lower rate of definitely diagnosing diseases. An MRI (Magnetic Resonance Imaging) is another option but it tends to have a high rate of identifying issues that might not actually be problematic.
Blood tests can also be performed to aid in the diagnosis, but these are not typically the main way to diagnose a disease. These might include tests, or serologies, for inflammation or infections, such as a rheumatoid factor, anti-nuclear antibodies, serum ACE, Lyme disease, and a general inflammation test known as the erythrocyte sedimentation rate (ESR).
One of the most specific ways to check for issues with the vocal cords, like suspected damage after surgery, is direct laryngoscopy. This procedure allows your doctor to examine your vocal cords directly and observe their movement, and is often combined with video recording to gain more detailed insights.
Other techniques possibly used include laryngeal electromyography, an electrodiagnostic test that assesses the health of your larynx’s muscles, and ultrasound imaging of your neck and larynx. These tests have limited availability and usage, and their utility will depend on the specific circumstances. For example, laryngeal electromyography is normally used for predicting the progress of symptoms that have been present for between 4 weeks to 6 months. Neck and laryngeal ultrasound, meanwhile, can be used to examine vocal cord movement and other nearby abnormalities, but cannot provide the same detailed images as a CT scan and can be less valuable in patients with obesity.
Treatment Options for Unilateral Vocal Cord Paralysis
The goal of surgery in unilateral vocal cord paralysis (UVCP) is to move the affected vocal cord towards the middle (a process called ‘medialization’), to help improve voice quality. The decision on when to do this surgery varies, but doctors usually suggest waiting for 6 to 9 months to see if the problem might get better on its own or with the help of the unaffected vocal cord.
One such procedure, called injection thyroplasty, involves putting a substance near the affected vocal cord to push it towards the middle. This makes it easier for the cord to make contact with the other one. This procedure can either be done under local or general anesthetic. There are several types of materials that have been used in this procedure—such as fat from your own body, skin from a cadaver, or substances like calcium hydroxy-apatite, methyl-cellulose, and hyaluronic acid. However, there isn’t any premium quality evidence suggesting which material works best. In the past, a substance called Teflon was used, but it’s no longer preferred due to complications.
A procedure called Type 1 Isshiki thyroplasty is another method, which is considered to be a more long-term solution. In this process, a small opening is cut into the thyroid cartilage (a structure in your neck that houses the vocal cords) and the affected vocal cord is moved towards the middle using an implant. Similar to injection thyroplasty, several types of implant materials have been used. Along with this, other procedures can also be performed at the same time and research shows that the voice outcomes are generally good after 1 and 3 years of surgery.
Laryngeal reinnervation is another procedure that reconnects working nerves near the recurrent laryngeal nerve to recover tone and movement within the voice box. Nerves like the ansa cervicalis, phrenic, and hypoglossal have been used and have shown good results.
Research compared the outcomes of all these procedures and found that while all methods have good evidence, no particular technique has been found to be significantly better in terms of voice outcome or quality of life. Although, some doctors find that Type 1 Isshiki thyroplasty has greater long-term benefits compared to injection techniques, current evidence shows that long-lasting injectable materials can give similarly good results over time. As such, surgery is usually considered after trying conservative treatments first, and the surgical technique used depends on the experience of the surgeon and the preference of the patient.
What else can Unilateral Vocal Cord Paralysis be?
The potential causes of UVCP (Unilateral vocal cord paralysis) are either cancerous or non-cancerous. Here are the details:
- Cancerous: Mostly lung and laryngeal cancers
- Non-cancerous: Usually due to injury or resulting from a medical procedure, with less common causes being neurological conditions, inflammation, or infections
- Idiopathic: This is a cause that is determined only after other possible causes have been ruled out
What to expect with Unilateral Vocal Cord Paralysis
The outcome or ‘prognosis’ for patients with Unilateral Vocal Cord Paralysis (UVCP) can greatly vary and mainly depends on what caused the condition in the first place. It’s estimated that about a third of patients will regain movement, though many may continue to struggle with their voice.
There’s a certain procedure called Laryngeal Electromyography that can provide helpful information about the prognosis of patients who consistently have a hoarse or weak voice, otherwise known as ‘persistent dysphonia’.
Possible Complications When Diagnosed with Unilateral Vocal Cord Paralysis
Voice and swallowing issues can noticeably impact the quality of one’s life, especially for individuals, such as teachers, singers, and secretaries, who heavily depend on their vocal abilities for their profession. The resulting psychological and financial stress from unilateral vocal cord paralysis (UVCP) can be quite significant. In some cases, if the vocal cords don’t completely close, it may lead to inhalation of foreign materials into the respiratory tract, known as aspiration. Although uncommon, aspiration can dangerously evolve into life-threatening aspiration pneumonia.
Possible Effects of UVCP:
- Significant impact on life quality
- Can create financial and psychological stress, particularly in voice-reliant professions.
- May lead to difficulty swallowing
- Potential risk of aspiration due to incomplete closure of the glottis
- Rare but possible development of life-threatening aspiration pneumonia
Recovery from Unilateral Vocal Cord Paralysis
Treatment for Unilateral Vocal Cord Paralysis (UVCP), a condition where one of your vocal cords is not able to move, often involves voice rehabilitation with speech and language therapists. This can happen both before and after surgery. The goal is to improve how well your vocal cords come together and close, by increasing pressure in your abdomen using techniques such as humming and deep breathing exercises.
Research has suggested that beginning voice therapy early might help reduce the need for surgery. After surgery, speech and language therapists are crucial in evaluating the voice quality. Even though there are many ways to measure voice quality, there isn’t a universally agreed method.
Preventing Unilateral Vocal Cord Paralysis
If you’re experiencing dysphonia – a condition that makes your voice sound different – it’s understandable that you might feel uneasy. Many people might worry that it’s a sign of cancer. However, it’s important to know that while cancer can be a cause, there are other reasons for this condition as well. Several of these causes can potentially be reversed or managed.
To ease your fears, know that there are various effective long-term ways to handle this condition, both with surgery and without. You also have the option to try different treatment methods to find the one that suits you the best.
Additionally, speech and language therapists can truly make a difference. They help you feel reassured and provide the necessary support throughout your journey with voice therapy. You’re not alone, and there’s hope in managing the changes in your voice.
