Acoustic Neuroma / Vestibular Schwannoma

Acoustic neuromas (also referred to as vestibular schwannomas) are benign tumors that are growths from the hearing or balance nerves.  As a consequence of their growth, they can cause permanent hearing loss, ringing or buzzing sounds in the ear (tinnitus) and dizziness/vertigo, compression of the brain and occasionally cause facial nerve weakness. 

Acoustic neuromas are rare and are found in the 1 in every 100,000 people.  They account for 6% of all brain tumors.  They do not spread throughout your body, but tend to cause problems with local growth by putting pressure on vital structures such as your brainstem, hearing nerve, balance nerves, facial nerve and sometimes even obstruct the flow of brain fluid causing a condition called hydrocephalus.  As you might expect, the smaller the tumor the fewer the symptoms, and the easier it can be removed safely.  Finding tumors while they are small gives you the best chance for protecting the vital structures that are near these tumors.  

In order to diagnose and manage these tumors certain specialized tests are needed.  These tests include:

• Hearing Test
• Balance Test (ENG)
• Brainstem Hearing Test (ABR/BAER)
• MRI (Magnetic Resonance Imaging)

Once the diagnosis has been made a treatment plan is established.  The treatment  plan is determined on several factors including:

• Size and location of the tumor
• Hearing status
• Age of the patient
• Health status of the patient

There are several options for acoustic neuroma treatment.  Although there are many listed below, keep in mind all tumors and patients are unique.  Your Neurotologist and Neurosurgeon will recommend the treatment options best suited for you.

Nonsurgical Management

Observation without surgery:  Acoustic neuromas are considered slow growing tumors (roughly 1 mm per year).   Yearly MRI scans are required indefinitely to assess growth of the tumor.  This option is a consideration for the following patients:

• Patients with small tumors, especially if their hearing is good
• Patients with serious medical problems
• Patients with a tumor on the side of an only hearing ear

Surgical Management

There are several different surgical approaches designed specifically to remove acoustic neuromas.  Some of the approaches allow for preservation of remaining hearing, while others will sacrifice any remaining hearing.  Your surgeon will recommend approaches which are best suited for your unique conditions. 

• Middle Fossa Removal
• Translabyrinthine Approach
• Retrosigmoid/Suboccipital Approach

Sterotactic Radiosurgery

This involves the use of a high intensity radiation beam that is directed toward the tumor.  This will not eliminate or remove the tumor but has the potential to stop its growth.  After treatment yearly MRI scans are required indefinitely to assess for growth of the tumor.  If the tumor continues to grow after the radiation treatment the risk of facial nerve injury and hearing loss is likely increased with surgery. 

Selection of appropriate candidates for surgery, radiosurgery, or observation is an evolving area of research. 

Advances

Advances in surgery and radiosurgery have allowed for better treatment results for acoustic neuromas than ever.  The Iowa Ear Center offers all treatment options for acoustic neuromas and aims to educate and guide patients through the evaluation and treatment process.

Follow-up Treatment

Once the acoustic neuroma has been treated, follow-up treatment consists of balance therapy and providing as much support as possible for the remaining hearing.  Since removal of the balance nerve is necessary in all cases of surgical treatment, rehabilitation of balance is always called for. Such therapy, also called vestibular rehabilitation, is usually successful. Most patients can return to close to their functioning level before the acoustic neuroma symptoms started.

Hearing loss in one or both ears can be treated in a number of ways, depending on the specific situation of the patient following removal of the neuroma.  Specialized hearing aids, and surgically implanted hearing devices (for example, the BAHA, and cochlear implant) can be used to maximize the hearing in each unique patient.