What are Vestibular Schwannomas?
Vestibular Schwannoma (also called acoustic neuroma, neurinoma, neurilemmoma) is an uncommon, non-cancerous growth (benign tumor) that generates in the eighth cranial nerve. This nerve passes through the internal auditory canal (inner-ear) and is responsible for relaying balance and auditory information to the brain. The seventh cranial nerve controls facial muscle functions and lies adjacent to the eighth nerve within the internal auditory canal. When acoustic neuroma develops on the eighth cranial nerve, the growth may eventually press against adjacent nerves, blood vessels and brain structures.
The formation of an acoustic neuroma is gradual and slow-growing in nature. In rare occasions, it can be large and expand at a rapid rate. In these few instances, the tumor may press against the brainstem (cerebellum) and interfere with vital functions.
Symptoms of Acoustic Neuromas
Tumor size is not directly correlated to the symptoms experienced by the patient. For example, a small growth may cause little or no symptoms in one individual while a tumor of the same size may raise severe cause for concern in others. Symptoms of acoustic neuroma typically include:
- Ringing in the ear (tinnitus)
- Hearing loss
- Dizziness (vertigo)
- Loss of balance
Facial numbness, weakness or paralysis can occur when the growth has affected the adjacent seventh cranial nerve which controls facial muscle functions.
In rare occasions, an acoustic neuroma may grow large enough to press against the brainstem and cause life-threatening complications and neurological damage. The normal flow of fluid between the brain and the spine can also be interrupted, causing a buildup of fluid in the brain which may result in pressure on the skull.
Available Treatment Options
Doctors can advise an audiometry (hearing test) to examine hearing loss, CT (computerized tomography) scans or MRIs (magnetic resonance imaging) to detect an acoustic neuroma.
Doctors may recommend simply monitoring the acoustic neuroma in cases where tumors are small, slow- growing or do not grow at all and show few to no symptoms. This option is also common for older patients (acoustic neuroma is typically found in individuals ranging in ages 30-60). Monitoring the tumor is also common in those who are at greater risk for complications during other forms of treatment. Patients who are simply not preferable candidates for alternative treatment methods will also have to monitor the growth. Regular hearing and imaging tests are commonly recommended every 6-12 months as part of the monitoring process.
Stereotactic radiosurgery, such as the kind provided by the CyberKnife system, allow for neurosurgeons to concentrate a precise dose of radiation to the specific tumor area. Imaging scans aid in determining where the beams of radiation are concentrated. The goal of the non-invasive procedure is to stop tumor growth without causing further damage and to maintain proper functions of the seventh and eighth cranial nerves when possible. Successive stereotactic radiosurgery sessions and monitoring are usually necessary to evaluate patient progress.
Surgery may be considered when other treatment options fail. If a tumor is large enough that its removal may complicate surrounding nerves and tissues, surgery may be ruled out. The surgery is performed with the patient under general anesthesia. Unlike stereotactic radiosurgery, in cranial surgery, the tumor is removed through either the inner-ear or a window made in the skull. The goals of traditional cranial surgery mirror those of stereotactic radiosurgery in which physicians hope to preserve nerve function and prevent loss of hearing, balance and facial muscle function.
Preserve Your Neurological Functions
Effective, minimally-invasive neurosurgical treatment is only a phone call away. If you are experiencing symptoms of a neuroma or have questions regarding cranial surgery, CyberKnife radiosurgery or vestibular schwannoma, contact or call a highly skilled neurosurgeon in New Jersey at 908-379-3998.