What is an acoustic Neuroma (Vestibular Schwannoma)
An Acoustic Neuroma (or Vestibular Schwannoma) is a benign tumour that arises from the VIIIth cranial nerve (Vestibular nerve) at a location in the brain known as the cerebello pontine angle.
Where are acoustic neuromas found? – Anatomy
The VIIIth cranial nerve is composed of the balance nerve (Vestibular) and the nerve of hearing (Cochlear). It arises from the brainstem and exits the skull through the internal ear canal to reach the balance and hearing organs. The VIIth nerve (Facial) also follows the VIIIth nerve. The Facial nerve controls the movement of one half of the face – raising eyebrows, frowning, closing eyes and smiling. It is therefore crucial for facial expression which is mostly how we human beings communicate our feelings.
Above and below the VIIth and VIIIth nerves are numerous other cranial nerves that control various other functions of the head and neck.
The brain stem, composed of the Midbrain, Pons and Medulla are crucial to our very existence. It harbours functions such as consciousness, breathing and the movement of our entire body.
Also in this location are numerous fine blood vessels that supply the brain far and wide.
What causes Acoustic Neuromas?
In short, we don’t really know. However, people who have had prior exposure to radiation seem to be more at risk of developing these tumours. As such, there is some debate at present about the effect of mobile phones. There is also a genetic disease known as Neurofibomatosis Type II which gives rise to acoustic neuromas on both sides.
What symptoms arise from these tumours?
The list below, covers common symptoms associated with acoustic neuromas but does not include all.
- Hearing loss in one ear
- Tinnitus (ringing in the ears)
- Dizziness and balance problems, including drop attacks
- Pain behind the ear
What treatments are available for this tumour?
Thankfully, because acoustic neuromas are benign, slow growing tumours, they can be cured.
Surgery is the most definitive way of curing this tumour. However, given that these tumours occur in such a crucial location, surgery is difficult and high risk. Surgeons who specialize in this form of surgery are regarded as being in the pinnacle of their specialty.
Neurosurgeons are experts at dealing with fine and delicate structures such as the cranial nerves, brain stem and blood vessels. ENT (Ear Nose and Throat) surgeons are most familiar with the internal ear canal and the hearing and balance organs. It therefore makes sense that this surgery be carried out by a team composed of a Neurosurgeon and an ENT surgeon who are highly specialized and have considerable experience in this field of surgery.
Surgery maybe performed via three routes
- Middle Fossa
The choice of approach is largely dependent on the surgeons’ choice followed by the presence of useful hearing and the size and position of the tumour.
Dr Shivalingam is highly specialized and trained in the field of acoustic neuroma surgery. She works with closely with ENT surgeons who are all highly trained in this type of surgery.
Together they form one of Australia’s leading acoustic neuroma surgical teams.
What do they do that’s different ?
- Dedicated specialist surgical team of anaesthetists and nurses.
- Utilise the principles of minimally invasive neurosurgery
- Intraoperative neuronavigation, accurately localizes large veins and the tumour.
- Cranioplasty – reconstruction of drilled out bone to eliminate the chance of post surgical headache.
- Post operative care in a dedicated Neurosurgical intensive care ward staffed by specialist neuro nurses.
- Stereotactic Radiosurgery (SRS)
This is a focused form of radiotherapy that halts the growth of the tumour.
It may be used for small tumours in older people.
The treatment stops the tumour from growing but doesn’t cure it.
The main advantage of SRS is that it is a treatment administered without an incision or an anaesthetic and so does not involve the risks associated with open surgery.
This form of treatment is only available at selected centres around the country. At RPAH we now have the latest Linac based Stereotactic radiosurgery system.
- Observation – “watch and wait”
Some tumours are very small and because we know they are slow growing, there is an option to “watch” the tumour.
This is done through serial MRIs.
If and when growth is observed, option 1 and 2 and re explored.
During a consultation with Dr Shivalingam, the above three treatment options will be discussed in detail. The pros and cons of each option will be described in detail and the “best” option will be recommended. The “best” option depends on a number of patient and tumour related factors.