Acoustic Neuroma

Treatment

The treatment of acoustic neuromas is complex and requires a sophisticated, experienced and well-coordinated team. At Mayo Clinic, the team may include:

• A neurologist (a doctor who specializes in diseases of the nervous system)
• An otologist (a doctor who specializes in the treatment of ear diseases)
• A neurotologist (a surgeon who specializes in diseases of the ear)
• A neurosurgeon (a brain surgeon)
• A radiologist (a doctor who specializes in interpreting medical images)
• A radiation oncologist (a doctor who specializes in radiation therapy)

At Mayo Clinic, specific treatments are determined by a patient's medical team based on:

• The patient's age, overall health and medical history
• The size and location of the tumor
• Information obtained from imaging tests or scans
• The patient's tolerance for specific procedures or therapies
• The patient's opinion or preference

Three treatment options are available for acoustic neuromas:

• Observation
• Microsurgical removal or reduction of the tumor
• Stereotactic radiation therapy (radiosurgery)

Observation

Acoustic neuromas are sometimes discovered while evaluating a patient for another medical condition, or when the tumor is very small with subtle symptoms. Since they are slow-growing, if discovered when very small, careful observation over a period of time may be appropriate for some patients.

A small tumor diagnosed in an elderly patient may only require observation of the growth rate of the tumor if disabling symptoms are not present. If it appears that the tumor will not need to be treated during the patient's normal life expectancy, treatment and its potential risks and complications can be avoided. Some tumors don't appear to grow at all.

Another group of people for whom observation may be preferred are those who have a tumor in their only hearing ear or better hearing ear. In such cases, growth is monitored and surgery is considered only if hearing is lost or the tumor size becomes life threatening.

In these patients, magnetic resonance imaging (MRI) of the head is done periodically to monitor tumor growth. If there is no growth, observation is continued. But if the tumor shows increase in size, treatment may become necessary.

Microsurgical Removal

The goal of surgery is to remove the tumor and avoid any new neurologic deficit such as facial weakness or hearing loss. Success in achieving these goals depends a great deal on the size and configuration of the tumor, and the patient's hearing status prior to the operation.

Surgery for acoustic neuromas is done under general anesthesia using an operating microscope. Usually, patients stay in the hospital four to five days after surgery.

A variety of surgical approaches are used for removal of acoustic neuromas. The choice depends on the location, tumor size, hearing level of the patient and the skill and experience of the surgeon.

Each approach has advantages and disadvantages, and excellent results have been achieved in all approaches. The surgeon and patient should thoroughly discuss the reasons for a selected approach.

Partial Tumor Removal

Some patients and their surgeons prefer partial removal of an acoustic neuroma in order to reduce the risk of complications, especially if the tumor is large, realizing that more surgery or stereotactic radiosurgery may be needed in the future.

By reducing the tumor size, it may no longer threaten the patient's health during his or her life expectancy and may preserve hearing in the affected ear. This approach may reduce the probability of any facial nerve dysfunction as a result of the surgery, but there is still a risk for hearing loss with partial removal. Periodic MRI scans are important to follow the potential growth of the remaining tumor.

Stereotactic Radiosurgery

Stereotactic radiosurgery is a method of precisely delivering radiation to tumor. It is usually performed as an outpatient using local anesthesia. No specific restrictions follow radiosurgery and most patients can return to work or nomal activities within 48 hours of the procedure. The goal of stereotactic radiosurgery is to stop the tumor growth.

Sometimes during brain surgery to treat acoustic neuromas not all of the tumor can be safely removed and some must be left behind. Radiosurgery is often used after surgery to treat remaining tumor tissue.

Treatment Results

See summaries of Mayo Clinic published reports on results of Gamma Knife™ treatment (one method of stereotactic radiosurgery) on the following topics:

• Comparison of microsurgical resection and stereotactic radiosurgery
  
• Enlargement of acoustic neuromas after stereotactic radiosurgery
  
• Patient choice in treatment of acoustic neuromas
  
• Lower radiation dose lowers risk of facial neuropathy