Treatment for acoustic neuroma depends on the size of the tumor and the symptoms it causes.
An uncommon medical condition that affects the vestibulocochlear nerve is a noncancerous tumor referred to as acoustic neuroma. Also known as vestibular schwannoma, this tumor grows on the main nerve that connects the inner ear to the brain.
- While it is likely that this tumor will grow slowly, if at all, if it becomes too large or grows too quickly, it can put pressure on the brain.
- If this occurs, treatment will be necessary to keep vital body functions from becoming affected.
Because this condition occurs in only about 1 out of every 100,000 people, it is not very common. It is not clear what actually causes the development of acoustic neuroma, though researchers believe that it is most likely due to genetic causes. An abnormality on chromosome 22, which usually suppresses tumor formation, may be involved. One risk factor of developing a tumor on the vestibulocochlear nerve includes radiation exposure in high levels, especially to the head and neck areas. Another identified risk for acoustic neuroma is having a parent who has neurofibromatosis type 2, which can lead to the development of tumors in the nervous system.
When the tumor presses against the vestibulocochlear nerve, it can cause varying levels of hearing loss, typically only on one side. This loss in hearing may occur immediately or over time. Other symptoms may include tinnitus, or ringing in the ears, difficulty with balance or coordination, vertigo, or tingling and numbness in the face. Trouble swallowing, changes in taste or voice, headache, and confusion are other symptoms that have been associated with acoustic neuroma. If the tumor is small or does not press against any nerves, there may be no symptoms at all.
A physician may wait to see if the tumor grows or becomes problematic before moving to more intensive treatments. For smaller tumors, the least invasive treatment option involves stereotactic radiation therapy to shrink the tumor or at least halt its progress. However, there is a risk for side effects, including hearing loss, facial numbness, and hydrocephalus. More intensive treatments may be necessary. Currently, there are three commonly used surgical methods for removing acoustic neuroma tumors.
- With the middle fossa approach, an incision is made and a small piece of bone removed from just in front of the ear and above the ear canal. With this method, hearing can be preserved in up to 70 percent of patients.
- For the retrosigmoid approach, also called the suboccipital approach, the tumor is accessed through an opening in the skull in the back of the head. Nearly half of all patients treated in this manner retain some of their hearing.
The translabyrinthine approach is typically reserved for those patients who cannot be treated through other methods due to the size or location of the tumor. It is more likely recommended for those who already experience difficulty hearing because it results in permanent loss of hearing. Bone is removed behind the ear, as well as a portion of the middle ear, to remove the tumor.