Acoustic Neuroma

Doctor using otoscope to look in a senior woman's ears

What is Acoustic Neuroma?

Acoustic Neuroma (AN) is typically a benign, slow-growing tumor that is located next to the 8th cranial nerve which is the vestibulochoclear nerve which carries hearing and balance impulses to the brain. It has also become known as a vestibular schwannoma since the mechanism of the tumor actually arises from the Schwann cells of the myelin sheath that coats the nerve cell and not from the neuron cells.

 

What are the symptoms of Acoustic Neuroma?

  • Loss of hearing, typically gradual, and in one ear some cases may experience a sudden loss of hearing
    persistent ringing in the ear (tinnitus)
  • Loss of balance, unsteadiness
  • Dizziness associated with vertigo
  • Numbness of the face, semi-paralysis of the face

 

What causes Acoustic Neuroma?

Medical researchers have not been able to identify a primary cause for the creation of the tumor. There is a strong correlation between acoustic neuroma and a malfunctioning gene on chromosome 22. In cases of a rare genetic disorder called neurofibromatosis type 2, acoustic neuroma can occur. Researchers have seen a correlation between acoustic neuroma and exposure to low-dose radiation during childhood. There is some data that weakly correlates working in noisy conditions and the development of acoustic neuroma.

 

What can happen if my Acoustic Neuroma is not treated by a doctor?

  • Continued attacks of severe vertigo in rare cases tumors continue to grow, compressing the brainstem and threatening your life
  • Continued loss of balance, hearing loss and face numbness persistent tinnitus or ringing in your ears

 

How is Acoustic Neuroma diagnosed by your doctor?

Your doctor will ask you several questions about when you first noticed hearing loss, their frequency, any facial pain, the severity of your dizziness and intensity of your headaches. Your doctor may then recommend a hearing test to establish a baseline and assess your current hearing status in each ear. Plus he or she may suggest a CT (computed tomography) test or MRI (magnetic resonance imaging) test to confirm the presence of an acoustic neuroma.
Some clinicians have used an eye test called electronystagmography which detects changes in eye movements that may indicate the presence of an acoustic neuroma.

 

How do you treat Acoustic Neuroma?

 

Watchful Waiting

In many cases, acoustic neuroma may have stopped growing, or may be growing very slowly, causing few hearing or balance issues. In these cases, watchful waiting may be your best option along with hearing and CT or MRI scans every twelve months. If the tumor begins to grow, or you develop more severe hearing and balance symptoms, your doctor may suggest more aggressive treatment.

 

Sterotactic Radiosurgery (SRS & Gamma Knife)

Sterotactic radiosurgery, or Gamma Knife surgery can be performed in an outpatient facility specializing in SRS. The treatment delivers precisely-targeted radiation in high-doses. SRS is painless and non-invasive, usually requiring several sessions. Tumors under 1.25 inches in width are ideal for stereotactic radiosurgery. For larger tumors, microsurgery is recommended. It may take months or a year before symptoms improve or disappear. One of the long-term benefits of radiosurgery is that hearing functions are not negatively affected.

 

Surgery

 

Decompression of Endolymphatic Sac

If symptoms of MD do not improve, your ENT&AA doctor may recommend an operation on your inner ear to decompress the endolymphatic sac, which plays a key role in your vestibular system. There are three types: simple decompression, decompression via a shunt, and eliminating the sac completely. Decompression surgeries were found to be successful in reducing vertigo in 75% of cases. Hearing is usually preserved.

 

Labyrinthectcomy & Vestibular Neurectomy

A labyrinthectomy will relieve vertigo problems, but will also result in hearing loss in the ear operated on. The operation surgically removes the inner ear. Another surgical option that eliminates a physical function is a Vestibular Neurectomy in which the surgeon cuts the nerve that controls balance in the affected ear. This option involves brain surgery and a stay of several days in a hospital. Hearing is usually not impaired.