Acoustic Neuroma

Signs and symptoms of acoustic neuroma are often easy to miss and may take many years to develop. They usually happen because of the tumor’s effects on the hearing and balance nerves. Pressure from the tumor on nearby nerves controlling facial muscles and sensation (facial and trigeminal nerves), nearby blood vessels, or brain structures may also cause problems.

As the tumor grows, it may cause more noticeable or severe signs and symptoms.

Common signs and symptoms of acoustic neuroma include:

Hearing loss, usually gradually worsening over months to years although in rare cases sudden and occurring on only one side or more severe on one side

Ringing (tinnitus) in the affected ear

Unsteadiness or loss of balance

Dizziness (vertigo)

Facial numbness and weakness or loss of muscle movement.

• There are three main courses of treatment for acoustic neuroma:
  • Observation
  • Surgery
  • Radiation therapy

• Observation is also called watchful waiting. Because acoustic neuromas are not cancerous and grow slowly, immediate treatment may not be necessary. Often doctors monitor the tumor with periodic MRI scans and will suggest other treatment if the tumor grows a lot or causes serious symptoms.

  Surgery for acoustic neuromas may involve removing all or part of the tumor.

  There are three main surgical approaches for removing an acoustic neuroma:

  • Translabyrinthine, which involves making an incision behind the ear and removing the bone behind the ear and some of the middle ear. This procedure is used for tumors larger than 3 centimeters. The upside of this approach is that it allows the surgeon to see an important cranial nerve (the facial nerve) clearly before removing the tumor. The downside of this technique is that it results in permanent hearing loss.
  • Retrosigmoid/sub-occipital, which involves exposing the back of the tumor by opening the skull near the back of the head. This approach can be used for removing tumors of any size and offers the possibility of preserving hearing.
  • Middle fossa, which involves removing a small piece of bone above the ear canal to access and remove small tumors confined to the internal auditory canal, the narrow passageway from the brain to the middle and inner ear. Using this approach may enable surgeons to preserve a patient’s hearing.

  Radiation therapy is recommended in some cases for acoustic neuromas. State-of-the-art delivery techniques make it possible to send high doses of radiation to the tumor while limiting expose and damage to surrounding tissue.

  Radiation therapy for this condition is usually delivered in one of two ways:

  • Single fraction stereotactic radiosurgery (SRS), in which many hundreds of small beams of radiation are aimed at the tumor in a single session.
  • Multi-session fractionated stereotactic radiotherapy (FRS), which delivers smaller doses of radiation daily, generally over several weeks. Early studies suggest that multi-session therapy may preserve hearing better than SRS.

  Both of these are outpatient procedures, which means they don’t require a hospital stay. They work by causing tumor cells to die. The tumor’s growth may slow or stop or it may even shrink, but radiation doesn’t completely remove the tumor.