Acoustic Neuroma

An acoustic neuroma is a tumor that forms on the vestibular nerve. The vestibular nerve links the inner ear and the brain and plays a critical role in our ability to move and balance. These tumors develop from Schwann cells, which is why clinicians often refer to them as “vestibular schwannomas.”

Acoustic neuromas are benign tumors. This means that they typically don’t grow aggressively the way malignant, or cancerous, brain tumors do.

However, even though they are benign, acoustic neuromas can cause a number of serious issues, including hearing loss and difficulty balancing. That’s why it’s important to be cared for by physicians who specialize in treating acoustic neuroma patients.

As part of the Restorative Skull Base Program in the Brain Tumor Center at Siteman Cancer Center, Washington University Physicians and oncologists are national leaders in the treatment of acoustic neuromas. They are developing new techniques that can eliminate acoustic neuromas while helping patients preserve or improve their quality of life, including a ground-breaking surgical procedure that restores patients’ hearing during surgery to remove the tumor.

What are the symptoms of an acoustic neuroma?

The signature symptom of an acoustic neuroma or vestibular schwannoma is hearing loss that occurs in one ear, also known as “unilateral hearing loss.” Patients often find that this hearing loss develops gradually, although 10-15% of patients will lose their hearing suddenly.

Hearing loss in a single ear cannot be explained by aging. If you are experiencing this kind of hearing loss, you should make an appointment with your doctor. He or she will likely recommend that you undergo an MRI.

Patients might also notice other symptoms, such as:

  • Tinnitus, or ringing in the affected ear
  • Loss of balance
  • Dizziness
  • Headaches
  • Confusion

A tingling or numb sensation in the face

Risk factors for acoustic neuroma

Acoustic neuromas can happen in anyone, although they are more commonly diagnosed in individuals between the ages of 30 and 70.

When acoustic neuromas or vestibular schwannomas appear in children and young people, they are typically caused by the rare genetic disorder neurofibromatosis type 2, or NF2. Vestibular schwannomas are a hallmark of NF2; patients with the condition are highly likely to develop tumors before they turn 30 years old.  In these patients, schwannomas often occur on both sides of the head, or “bilaterally,” instead of on a single side.

If your child has been diagnosed with neurofibromatosis type 2, the Neurofibromatosis Center at the Washington University School of Medicine offers world-class care and support. Learn more here.

Treatment for acoustic neuroma

Not all acoustic neuromas need to be treated. If your tumor is not causing symptoms and you are older in age, for instance, your care team may decide to monitor the tumor rather than pursue active treatment.

If you are experiencing symptoms, however, you will likely be recommended to undergo surgery to remove as much of the tumor as possible. Radiation therapy may be used instead, depending on your age and state of health, and in many cases, can achieve outcomes similar to surgery.

It’s important to keep in mind that once an acoustic neuroma has begun to cause symptoms, those symptoms often can’t be reversed. Even after undergoing treatment, patients still struggle with hearing loss, balance issues, and, in some cases, facial nerve paralysis.

The team at Siteman Cancer Center understands that acoustic neuroma patients want to live active, healthy lives. They are conducting research and clinical trials that could help you make a more complete recovery from your tumor. Your well-being and comfort are a top priority to our providers.

Surgery for acoustic neuroma

Surgery for acoustic neuroma is technically demanding and requires a specialized team that is experienced with this specific tumor. Through recruitment of talent and depth of experience, the Siteman surgeons have developed a special expertise to remove these tumors. Depending on the exact size and location of the tumor, the procedure can sometimes be conducted using a minimally invasive, “keyhole” technique, in which the surgeon enters the brain and extracts the tumor through a small hole drilled in the skull.

The acoustic neuroma team is adept in all surgical approaches, including middle fossa, translabyrinthine, and retrosigmoid approaches. The middle fossa approach uses a curvilinear incision that begins in front of the ear and travels upwards whereas the translabyrinthine and retrosigmoid approaches use an incision behind the ear. They may also use additional tools, including neuronavigation (“GPS” for the brain), an operating microscope, and real-time neuromonitoring to assess the function of critical nerves.

After the surgery is performed, most patients remain in the hospital for 3 days.

Radiation therapy for acoustic neuroma

If your care team determines that you are not a good candidate for surgery, radiation therapy may be an effective treatment for your tumor.

Siteman Cancer Center offers several types of advanced radiation therapy that can achieve excellent results in acoustic neuroma patients. These techniques deliver highly concentrated doses of radiation to targets, making them ideal for individuals with acoustic neuromas of certain, generally smaller, sizes.

  • Gamma Knife: Gamma Knife stereotactic radiosurgery is a form of radiation therapy that can replace surgery in certain cases. It delivers a highly concentrated dose of radiation to the tumor while leaving the surrounding areas intact. Often completed in a single session, the Gamma Knife procedure triggers cell death in tumor cells.
  • Proton beam radiation therapy: During proton beam therapy, the tumor is hit with a single stream of protons. Unlike other forms of radiation therapy, the proton beam can be adjusted to stop at a specific depth, which means that it won’t touch any of the normal tissues beyond the tumor site. Siteman was the first institution in the region to offer proton beam technology.

Clinical trials for acoustic neuromas

Washington University neurosurgeons and physicians at Siteman are pioneering a new technique to reverse hearing loss caused by acoustic neuromas.

The technique is performed at the same time as surgery to remove the tumor. The surgical team uses electrodes to stimulate the patient’s cochlear nerve, testing whether the cochlea is still functional. If the cochlea is found to be functional, the surgical team will place a cochlear implant, allowing the patient to regain some or all of their hearing.

This ground-breaking procedure is available only in a clinical trial at the Washington University School of Medicine. If you have experienced hearing loss due to your acoustic neuroma, this may be a real option for you.