Acoustic Neuroma

What is an acoustic neuroma?

An acoustic neuroma, also called a vestibular schwannoma, is a benign (noncancerous) ear tumor that affects your hearing and sense of balance.

The tumor develops on your 8th cranial nerve (vestibulocochlear), which is the nerve that sends signals from your inner ear to your brain so you can hear and maintain your balance.

Acoustic neuromas don’t spread like cancerous tumors. As they grow, they can affect hearing, cause ringing in your ear (tinnitus), affect balance, and cause facial weakness or facial numbness. Treatment may include surgery, radiation therapy and, in rare cases, chemotherapy to treat the tumor.

Are acoustic neuromas common?

No, they aren’t common. Each year, about 1 in 100,000 people develop an acoustic neuroma. People ages 65 to 74 are more likely to have an acoustic neuroma than younger adults and children.

What are the symptoms of an acoustic neuroma?

The most common early symptom is hearing loss in one ear. Other symptoms may include:

• Tinnitus (ringing in the ears).
• Balance issues.
• Vertigo.

Acoustic neuromas grow very slowly. As they grow, they may cause the following symptoms:

• Facial paralysis or numbness.
• Headaches.
• Nausea and vomiting.
• Changes in your sense of taste.
• Difficulty swallowing (dysphagia).
• Blurred vision or double vision.

What causes acoustic neuromas?

These tumors develop when Schwann cells multiply. These cells support and protect the balance and hearing nerves in your peripheral nervous system. Researchers don’t know why this happens. They do know people with neurofibromatosis type 2 may develop bilateral acoustic neuromas. Bilateral acoustic neuromas are tumors that develop on the auditory nerves on both the right and left sides of your brain.

How is an acoustic neuroma diagnosed?

Your healthcare provider will ask you about your symptoms and perform a physical exam. They may do the following:

• Imaging tests, like magnetic resonance imaging (MRI) and computed tomography (CT) scans.
• Hearing tests, including auditory brainstem response.
• Balance tests.
• Electronystagmography.

What are treatments for an acoustic neuroma?

Treatments vary depending on factors like:

• The tumor size and location.
• How the tumor affects your hearing and balance.
• Your age and overall health.

Treatment options include:

• Observation: If tests show the tumor isn’t growing and you have no symptoms, your provider may recommend observation. They’ll do regular MRIs to look for changes.
• Stereotactic radiosurgery: This therapy targets tumors with beams of radiation focused on the tumor while limiting the impact on nearby healthy tissue.
• Microsurgery: Neurosurgeons use special instruments that let them do surgery in very small areas of your body. This is the only treatment that can eliminate an acoustic neuroma.
• Chemotherapy: In rare cases, providers may use the chemotherapy drug bevacizumab (Alymsys®, Avastin ®, MVASI ®, Zirabeva ®). This drug may shrink tumors, which increases the amount of time that children with acoustic neuroma will be able to hear. The drug also is treatment for radiation necrosis, which is a complication of radiation therapy.
• Vestibular rehabilitation therapy: Sometimes, surgery involves removing parts of nerves that control balance. Vestibular rehabilitation is therapy that helps you compensate for losing those nerves and the functions they manage.

Types of microsurgery

• Middle fossa approach: Your neurosurgeon may recommend this surgery if the acoustic neuroma is in your ear canal and is relatively small. It involves making a cut (incision) on the side of your head so your neurosurgeon can access your inner ear, separate your nerves from the tumor and remove it.
• Retrosigmoid approach: In this surgery, your neurosurgeon makes an incision behind your ear so they can access part of your skull and inner ear canal and remove the tumor.
• Translabyrinthine approach: If you have total hearing loss in one ear, your neurosurgeon may recommend this approach. In translabyrinthine surgery, they make an incision behind your ear and remove the bones in your inner ear to remove the tumor.

Complications of microsurgery

Your care team will discuss possible post-surgical complications and how to treat and manage them. Issues that may arise after surgery include:

• Hearing loss in one ear.
• Facial paralysis that may be temporary or permanent.
• Tinnitus.
• Cerebrospinal fluid (CSF) leaks.
• Balance issues.
• Difficulty swallowing.
• Dizziness.
• Double vision or dry eyes.
• Headaches.
• Infection.
• Meningitis.
• Tumor growing back.

What can I expect if I have an acoustic neuroma?

That depends on your situation, including the type of surgery and potential complications. Your neurosurgeon will explain treatment options and complications so you know what to expect, including:

• Treatment options if the tumor comes back.
• Devices that may improve hearing loss from surgery, including bone conduction hearing implants or CROS (contralateral routing of signals) hearing aids.

How do I take care of myself?

If you have an acoustic neuroma, your healthcare provider may decide to monitor your situation before doing treatment. You may feel anxious or worry that any change in your hearing or balance means the tumor is growing. In that case, ask your provider about specific changes that indicate the tumor is affecting your nerves.

If the condition causes symptoms, your provider may recommend surgery to remove the tumor. In some cases, surgery affects nerves that control your ability to maintain balance. In that case, your provider will recommend that you have vestibular rehabilitation therapy.

What questions should I ask my healthcare provider?

If you have an acoustic neuroma, consider asking your healthcare provider:

• Do I need treatment or will you simply monitor the tumor?
• What is the chance I’ll have useful hearing in my ear?
• How likely is it that the acoustic neuroma will come back after surgery or radiation therapy?
• Am I at higher risk for other types of tumors?
• What are the risks and benefits of acoustic neuroma surgery?
• Will I need rehabilitation after surgery?