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 Introduction
Acoustic Neuromas are benign slow growing tumors, which arise on the nerves of hearing and balance. This term is actually a misnomer since the tumor is actually on the vestibular nerve, rather than the acoustic nerve. In addition the tumor is schwannoma, rather than a neuroma. The proper term for the condition is vestibular schwannoma. This nerve, which is the nerve of hearing and balance, is also called the vestibulo-cochlear or the eighth nerve.
Symptoms
Patients typically complain of hearing loss in one ear, ringing (tinnitus) in the affected ear, dizziness, and loss of balance.
Diagnosis
The diagnosis is made by MRI with and without contrast to evaluate the tumor size, location, and involvement of adjacent brain. Formal hearing tests (audiograms) need to be performed to evaluate degree of hearing loss.
Treatment
Only rarely do vestibular schwannomas pose any immediate threat to life. Some of these tumors may remain dormant or grow slowly over many years and some small tumors can be observed without treatment. However, most VS should be treated especially if there is documented evidence of growth or if the tumor is causing a significant neurological deficit.
 There are several operative approaches which can be taken to remove the tumor. The middle fossa approach is directed above the ear under the temporal lobe of the brain, and is sometimes selected for very small tumors. Another approach, the translabyrinthine approach, directed behind the ear through the mastoid to the area under the brain, destroys hearing and is not suitable for patients in which there is the opportunity to preserve hearing on the side of the tumor. The translabyrinthine approach is not suitable for very large tumors. The third approach which we most commonly select, called the retrosigmoid approach, is directed through the area behind the ear. We utilize this approach because it is suitable for all size tumors, small or large. The retrosigmoid approach offers the potential for preserving hearing in every patient, although hearing preservation can be achieved on the side of the tumor in only about one-half of the patients who have small tumors and good hearing. It is infrequent that hearing can be preserved on the side of the tumor in patients with large tumors. Another risk of acoustic neuroma treatment is facial paralysis. We feel that the retrosigmoid approach offers the best opportunity for preserving the facial nerve, a goal which can be achieved in more than 95% of operations.
Over the past decade, another treatment approach, called radiosurgery, has become increasingly popular. Radiosurgery is an outpatient procedure which starts with the attachment of a "head ring" under local anesthesia. After detailed computer planning, hundreds of very small radiation beams are focused on the tumor. The treatment involves no incisions and requires no recovery time. Long term tumor control rates are quite high and the risk is very low.
At the University of Florida, over 100 vestibular schwannomas are treated yearly, using open surgical or radiosurgical methods. The benefits and risks of each of the different treatment alternatives is carefully reviewed with each patient so that they can make a well informed decision about which treatment would be best for them.
Vestibular schwannoma sugery is performed by Dr. Friedman and Dr. Lewis.
Acoustic Neuroma Association
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