Acoustic neuromas are non-cancerous tumours in the ears which can affect a person’s hearing and balance. Here, we discuss acoustic neuroma causes, symptoms, treatments and survival rates.
What is an acoustic neuroma?
Acoustic neuroma, also known as vestibular schwannoma, is a type of tumour that grows in the inner ear. It is a non-cancerous tumour that develops from Schwann cells, which are cells found surrounding the peripheral nervous system (PNS).
Typically, Schwann cells insulate and protect the PNS. However, sometimes, they can become benign tumours and occur in any nerve across the body.
In the case of an acoustic neuroma, this benign tumour can occur in the vestibular nerve, which is a nerve that connects the inner ear to the brain.
What causes acoustic neuromas?
Acoustic neuromas are considered rare, with only one in every 100,000 individuals diagnosed with this condition.
Most often, these benign tumours are found in adults and not children. Women between the ages of 30 and 60 are more susceptible to this condition than men.
Researchers and medical practitioners don’t know why acoustic neuromas occur.
One widely held hypothesis is that this tumour may have something to do with the Neurofibromatosis type 2 (NF2) genetic condition, which results in tumours that grow on the nerves.
Types of acoustic neuroma
Acoustic neuromas are classified as either unilateral/sporadic tumours or bilateral/genetic tumours.
- Unilateral acoustic neuromas occur without genetic precursors and often happen only on one side of the body.
- Genetic acoustic neuromas occur because of a genetic predisposition to NF2 and may appear on both sides of the body, sometimes multiple times.
Acoustic neuroma symptoms
- Loss of hearing
- Loss of inner ear balance, which leads to unsteadiness.
- Dizziness
- Tinnitus (i.e., constant ringing sound in the ears)
- Numbness in the facial muscles
- Difficulty speaking and swallowing
- Build-up of fluid in the brain
Acoustic neuroma complications
Complications depend on the stage/progression of the condition. In some cases, hearing and balance returns after tumour removal.
However, in some instances, patients permanently lose hearing in either or both ears. Additionally, there may sometimes be life-threatening complications in patients where the tumours press against the brain stem.
Our doctors will be able to provide better clarity to patients about their prognosis. However, with timely detection and treatment, patients can ensure any acoustic neuroma complications are only temporary.
Acoustic neuroma stages and size classification
Acoustic neuroma progression is diagnosed based on the Koos classification. Here is a list of acoustic neuroma stages based on size classifications:
| Grade | Size (mm) | Description | Symptoms |
|---|---|---|---|
| I | 0 mm (Small) | Intracanalicular – confined to the internal auditory canal (IAC | No dizziness, imbalance or tinnitus. |
| II | Less than 10 mm and all the way up to 20 mm (Medium) | Starts within the IAC and then may move beyond it and extend into the Cerebellopontine angle (CPA) | Occasional dizzy spells and mild imbalance. Tinnitus is mild and sporadic. |
| III | Above 20 mm and up to 40 mm (Medium to large) | Tumour continues to occupy the CPA and now starts to reach toward the brain stem, but there is no compression yet, although brain stem compression may occur in a little time. | Persistent tinnitus that starts to get louder, increased imbalance and vertigo. Hearing will start to get affected. |
| IV | Above 40 mm (Large) | Tumour is very large and may lead either to severe brain stem compression or displacement, damage or deformation of the brain stem and the fourth ventricle, which runs alongside it, entirely. | Severe and constant tinnitus, which affects day-to-day tasks. Extreme dizziness and persistent loss of balance. Hearing may be partially or fully lost. |
Acoustic neuroma survival rate
It has been found that acoustic neuroma tumours grow in size within four years of diagnosis, only in about 30% of the cases. The other 70% don’t display tumour growth, and with quick treatment, the acoustic neuroma can be removed.
Treatments for acoustic neuroma
The diagnosis of acoustic neuroma is made using a combination of techniques such as audiograms, ENG, MRI, CT and ABR. Once the tumour has been staged, patients may be recommended one of the following acoustic neuroma treatments:
- Observation: If the tumour size is very small or the patient has other medical conditions, doctors may choose to wait and monitor the tumour closely. Then, depending on the results, we may take other treatment decisions.
- Surgical resection of the acoustic neuroma: Once the neuroma is large in size, our doctors may choose to partially or fully resect the tumour to prevent it from affecting brainstem health, facial movement and hearing/balance.
One of three approaches is used for surgically treating this tumour:- Suboccipital: Access to the tumour is gained from the occipital bone
- Middle fossa: In this surgery, the tumour is accessed through a hole in the temporal bone
- Translabyrinthine: Access to the tumour is obtained by drilling a hole in the mastoid bone
Depending on the patient’s condition and type of surgery done, 20%-80% of patients will preserve partial/total hearing.
- Stereotactic radiosurgery: This treatment is used to slow down or stop tumour growth if possible. In some cases, this is offered as the first course of treatment. In others, it is used after surgery to target any remnants of the acoustic neuroma.It’s been found that radiosurgery offers tumour control by up to 95% and preserves hearing by 70%. Currently, clinical trials are ongoing to devise other treatment techniques and medications to address acoustic neuromas.
In conclusion
Acoustic neuroma doesn’t have to reduce patients’ quality of life. It has been found that the faster the diagnosis for this condition, the better the prognosis for the patient.
Even small changes in lifestyle and care can improve the quality of life of patients with acoustic neuroma tremendously. So, allow a qualified acoustic neuroma specialist ENT to provide you with a customised treatment plan based on your condition.
At the CK Birla Hospital, our ENTs and oncologists have a vast experience in diagnosing and treating acoustic neuromas. Our cutting-edge imaging systems, endoscopic instruments and professional support staff will help treat your tumour and help you live your life just the way you want. Book an appointment with our leading ENT specialist Dr Anish Gupta.
