John S. Oghalai, MD, chair of the USC Caruso Department of Otolaryngology – Head and Neck Surgery at Keck Medicine of USC, explains the most important things you need to know about acoustic neuromas.
Hearing loss can be a part of aging, but sometimes, it can be caused by a more serious issue like an acoustic neuroma. Here are answers to some commonly asked questions about its causes, symptoms and treatment.
What is an acoustic neuroma?
An acoustic neuroma, also known as a vestibular schwannoma, is the second most common tumor inside the head. It originates from the sheath of the balance nerve. Acoustic neuromas are usually slow-growing and account for approximately 7.5% of brain tumors.
How do you get one?
It’s not well understood what causes an acoustic neuroma. For most acoustic neuromas, the cause at the level of the cellular machinery is the failure of a “governor” gene to exert its effect in suppressing the growth of Schwann cells — those cells responsible for coating nerve fibers with insulation. The result is wart-like growth of these cells to produce a neuroma.
The only environmental exposure that has been definitively associated with an increased incidence is radiation exposure to the head. No evidence currently exists for an association between cell phone use and the development of these tumors.
For the most part, it is not an inherited disease, however 5% of cases are associated with a genetic disorder called neurofibromatosis type 2. The vast majority of tumors are sporadic (nonhereditary).
What are the symptoms of an acoustic neuroma?
Symptoms can be associated with the size of the tumor, but this is not always consistent. The most common first symptom is one-sided hearing loss and ringing or fullness in the ear. Individuals may also experience balance issues, dizziness and numbness or tingling on one side of their face.
When should you consider treatment?
If you’ve been diagnosed with an acoustic neuroma, it’s a good idea to consult with a highly experienced program that can assess your unique needs and identify the care plan that is right for you. This is based on multiple factors such as tumor size, existing level of hearing, symptoms and age. After a thorough review of your individual case with an acoustic neuroma expert, you can then make an informed decision on how to treat your tumor.
How is an acoustic neuroma treated?
The goal of treatment is to stop the degeneration of surrounding cranial nerves. If you are a candidate for hearing preservation, the goal is to preserve your hearing to the level it is at when you are first diagnosed, but it does not recover your hearing to a prior state. Maintaining facial nerve function and drastically minimizing the need for any future treatment is a top priority.
Depending on the size of the tumor, the age and medical condition of the patient, various procedures may be done.
Microsurgery
Surgery is performed in an operating room where a skull-base surgical team uses the latest microsurgical approaches and equipment. There are three main microsurgical approaches for the removal of an acoustic neuroma. The approach used for each individual patient is based on factors such as tumor size, location, skill and experience of the surgeon. The surgeon and the patient should thoroughly discuss the reasons for a selected approach.
Radiosurgery
With radiosurgery, the goal is to stop the growth of your tumor without injuring important structures around the tumor. This does not lead to removal of the tumor but may potentially stop further growth or shrink it over time. Radiosurgery is generally reserved for tumors under 2.5 cm in diameter. For young, healthy candidates with active lifestyles and a desire to preserve their hearing, surgery, as opposed to radiation, is often recommended.
Watch and Wait or Observation
A watch and wait strategy can be a good start if your tumor is small and you are experiencing very minimal symptoms. This approach generally involves a second MRI in six months and annually provided there is no growth and/or symptoms have not changed.
What can I expect if I have surgery for an acoustic neuroma?
Surgery to remove an acoustic neuroma will take up most of the day. Afterward, you will stay in the intensive care unit (ICU) one night so you can be closely monitored. The next day, you will usually be transferred to a regular room. If needed for balance problems after surgery, physical therapy will be ordered to help you get up and walk around. Some people need to use a walker after surgery to help prevent falls.
Patients are considered safe to go home when they are:
- Steady on their feet
- Eating and drinking fluids without vomiting
- Not experiencing extreme dizziness
- Controlling their pain
- Experiencing no complications
This can be anywhere from 2 to 6 days after surgery.
Some people have weakness of half their face after surgery. This can occur immediately or have a delayed onset by a few days. If this happens, you’ll be asked to use lubricating eye drops every 1-2 hours during the day. At night, you’ll apply lubricating eye ointment, and your treatment team will teach you how to tape your eye shut so it doesn’t get dried out, red or scratched.
After surgery, it’s normal to have some pain, discomfort, headaches, tiredness, dizziness, feelings of being off-balance and weakness. You may have some difficulty focusing while reading or being on the computer, and you’ll likely need frequent breaks. This may last several weeks to several months.
You should try to stay as active as possible after surgery; however, you should not bend over, exert yourself or lift anything heavy for at least one month after your procedure.
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