The diagnosis of an acoustic tumor (cerebellopontine angle tumor) usually is based on hearing loss, ringing in the ear, and sometimes dizziness and fullness. Sometimes they are present with only a distortion, fullness, or slight unsteadiness.

General Comments

Acoustic tumors are fibrous growths which originate from the balance and hearing nerve, and are not malignant. They do not spread to other parts of the body, other than by direct extension. They occur at a rate of approximately one per 100,000 individuals in the general population. They constitute approximately 10% of all brain tumors. They are located between the brain and the inner ear, adjacent to vital brain centers. As they grow, they cause involvement of the surrounding nerves. If they are allowed to grow over a long period, they press into the vital brain centers, and will eventually cause pressure on the brain and ultimately this is fatal. In most cases, these tumors grow slowly; however, in other people, the growth is quite rapid and severe and multiple symptoms may develop. At times there may be bleeding into one of these tumors causing sudden new symptoms.

A person who has an acoustic neuroma has a problem, which involves life or death. Many diagnostic procedures are used to be certain as possible of an accurate diagnosis, and to determine how extensive the tumor is. In treating these tumors, the preservation of life is the most important objective. When the tumors are small, loss of life is less than 1%. When they are medium sized, it is approximately 3%, an in large tumors it may be as much as 5%. The secondary objective of surgery is to preserve as many vital structures as possible. In many cases, a completely normal life results following surgery. In others, minimum or even maximum degrees of handicap may result.

Diagnosis of acoustic neuroma

The diagnosis of an acoustic, neuroma begins with a complete history and conventional audiologic evaluation. Following this, if there are any indications of a tumor, an auditory brainstem response (ABR) test is done with a computerized audiometer. These uses a sophisticated computerized audiometer to analyze the electrical activity of the hearing nerves on both sides to determine if there is a normal conduction of the signals to the brain. If the conduction is slowed down on one side, this may indicate a tumor. Electronystagmography (test of the balance system) is also used to test for acoustic neuromas. If the balance mechanism is damaged on one side, this may be indicative of a tumor on that side. CT scanning and magnetic resonance imaging (MRI) are sophisticated imaging methods used to examine (by picture) the cerebellopontine angle region of the brain to determine if there is an acoustic neuroma present. Since this type of tumor is closely associated with the seventh cranial nerve, which gives movement to the same side of your face, a special test of facial nerve function (electroneuronography) may also be performed.

Treatment

The conventional treatment for an acoustic neuroma is surgery. The main goal is the preservation of life, with a minimum of future physical disturbances. To accomplish this, a team consisting of a neurotologist, neurosurgeon, as well as an internist, anesthesiologist, and specially trained surgical nurses, provides the surgery, as well as the pre- and postoperative care. The neurotologist and the neurosurgeon are co-surgeons during the surgery.

The patient is usually admitted to the intensive care unit for 24-48 hours postoperatively for close observation. After that period, the patient is transferred to the floor or to an intermediate unit. They usually are in the hospital for 7 – 10 days.