Acoustic Neuroma

  What is it?

  An acoustic neuroma (sometimes termed vestibular schwannoma) is a benign
  (non-cancerous) tissue growth that arises on the eighth cranial nerve leading from
  the brain to the inner ear. This nerve has two distinct parts, one part associated
  with transmitting sound and the other sending balance information to the brain
  from the inner ear. These pathways, along with the facial nerve, sit adjacent to
  each other as they pass through a bony canal called the internal auditory canal.
  This canal is where acoustic neuromas originate from the sheath surrounding the
  eighth nerve. The facial nerve provides motion of the muscles of facial expression.

  Acoustic neuromas usually grow slowly over a period of years. They expand
  in size at their site of origin and when large can displace normal brain tissue
  The brain is not invaded by the tumor, but the tumor pushes the brain as it enlarges.
  The slowly enlarging tumor protrudes from teh internal auditory canal into an area
  behind the temporal bone called the cerebellopontine angle. The tumor now assumes
  a pear shape with the small end in the internal auditory canal. Larger tumors can
  press on another nerve in the area (the trigeminal nerve) which is the nerve of
  facial sensation. Vital functions to sustain life can be threatened when large
  tumors cause severe pressure on the brainstem and cerebellum part of the brain.
  Tumors are typically described as small (less than 1.5 cm.), medium (1.5 cm. to 2.5
  cm.) or large (more than 2.5 cm.).

  What are the symptoms?

  Early symptoms are easily overlooked, thus making diagnosis a challenge. However, there
  usually are symptoms pointing to the possibility of an acoustic neuroma.

• The first symptom in 90% of those with a tumor is a reduction in hearing in one ear, often accompained by ear noise or tinnitus. The loss of hearing is usually subtle and worsens slowly, although occasionally a sudden loss of hearing is noted. There may be a feeling of fullness in the affected ear. These early symptoms are sometimes mistaken for normal changes of aging, and diagnosis is often delayed.
• Since the balance portion of the eighth nerve is where the tumor arises, unsteadiness and balance problems may occur during the growth of the neuroma. The remainder of the balance system sometimes compensates for this loss, and no imbalance will be noticed.
• Larger tumors can press on the trigeminal nerve, causing facial numbness and tingling, constantly or intermittently.
• Increase of intracranial pressure may be experienced with headaches, clumsy gait and mental confusion. This is a life-threatening complication requiring urgent treatment.

  What treatments are available?

  For an acoustic neuroma:

• Observation is sometimes indicated for certain elderly patients and those with a tumor in their better or only hearing ear.
• Microsurgical removal (partial or total) may be indicated when there is a need to reduce the risk of complications, with the understanding that further surgery may be needed in the future.
• Stereotactic radiation therapy, referred to as "radiosurgery" or "radiotherapy", is a technique based on the principle that radiation delivered precisely to the tumor will arrest its growth while minimizing injury to surrounding nerves and brain tissue

  For symptoms which may accompany an acoustic neuroma:

• Balance Retraining Therapy is a specialized form of physical therapy which addresses certain symptoms (e.g., imbalance and unsteadiness) associated with an acoustic neuroma. This type of therapy is often beneficial pre-surgery, post-surgery and when surgery is not indicated.

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