An acoustic neuroma, also referred to (more accurately) as a vestibular schwannoma, is a benign tumor of the vestibular nerve that begins within the base of the skull and slowly expands into the skull cavity. Acoustic neuromas arise from the Schwann cells, which are responsible for the myelin sheath in the peripheral nervous system. Acoustic neuromas appear near the inner ear and their symptoms occur progressively in most patients. Some of these symptoms include slow and progressive destruction of hearing in the affected ear, a sense of imbalance and an altered gait, vertigo, nausea and vomiting. Interestingly, there is minimal or no tumor growth in some individuals.
If an acoustic neuroma does grow large enough, however, it can lead to increased intracranial pressure, which is associated with severe headaches and altered consciousness. The adjacent brainstem may also be compressed by these larger tumors, which affects a variety of local cranial nerves. The nearby facial nerve may also be affected. An acoustic neuroma that pushes against this nerve can lead to such symptoms as facial weakness and decreased facility of facial movements, facial numbness, sensory impairment, taste loss and the suppression of glandular secretions.
In the United States alone there are approximately 3,000 cases of acoustic neuroma diagnosed every year. Acoustic neuromas makes about 5 – 10% of all intracranial neoplasms in adult patients. Peak incidence of acoustic neuromas occurs during the fifth and sixth decades of a patient’s life and both men and women are affected equally. In the treatment of acoustic neuroma, Gamma Knife surgery has proven exceptionally effective. Over the past 25 years, thousands of patients suffering from acoustic neuromas have been successfully treated by means of the Gamma Knife and the results compare favorably with the published results of microsurgery.
While microsurgery is currently the only method of physically removing an acoustic neuroma, it involves much higher risks than Gamma Knife procedures. In the treatment of acoustic neuromas, Gamma Knife surgery avoids the need for actual incisions. There is minimal discomfort and no post-treatment recovery period. While Gamma Knife treatments do not entail the physical removal of an acoustic neuroma, they do enable doctors to control, halt, and sometimes even reverse the growth of the tumor.
Reports of re-operation on individuals treated with the Gamma Knife being more difficult or dangerous are unsubstantiated. Re-operation is quite rare and failure of control may be retreated by the use radiosurgery. In the treatment of acoustic neuromas, radiosurgery is an effective and safe tool. Arguments that radiosurgery treatments may lead to cancer in the affected tumor are also unfounded, as there are no reports of cancer in a tumor being caused by radiosurgery.