Acoustic Neuroma Surgery
Acoustic neuroma surgery is the main treatment used for this type of ear tumour. Acoustic neuromas are not usually malignant, aggressive cancers; they are a type of benign tumour that affects the acoustic nerve. This is the main nerve that carries signals from the inner ear to the brain, allowing information from the outside environment to pass to the brain to give us the sense of hearing.
The ear itself has two main functions: one is hearing, the other is balance and the ability to maintain posture. The inner ear contains intricate structures such as the cochlea and the organ of Corti, which detect our position in space constantly. Any disturbances can affect the inner ear, and cause us to feel sick or dizzy or to lose our balance.
How Does Acoustic Neuroma Make You Feel?As this type of ear tumour grows on the acoustic nerve, this can affect the way that the nerve transmits signals both about hearing and about balance. Someone who develops acoustic neuroma can therefore experience a wide range of different symptoms, including intermittent loss of hearing, increasing problems with ringing in the ear (tinnitus), periods of feeling nauseous and dizzy, and losing their balance for no apparent reason.
These symptoms can be caused by several other medical conditions, so diagnosing acoustic neuroma can take some time. If more obvious causes are ruled out, it is usual to be referred to a medical specialist to have further investigations. These can include imaging tests, such as computer tomography scanning (a CT scan), an X-ray or magnetic resonance imaging scanning (an MRI scan).
Acoustic Neuromas And The Acoustic NerveWhen these imaging test results become available, the specialist will examine them carefully, and most acoustic neuromas are detected. They are very slow growing tumours that start off in the cells that insulate the nerve. Most of the larger nerves in the human body are insulated in much the same way that cables insulate electrical wires in domestic appliances. This insulation around nerve cells takes the form of a protein called myelin. Myelin sheaths are produced by specialist cells called Schwann cells. These are named after the scientist who originally discovered their existence.
Nerve cells and the cells associated with them rarely form tumours, and acoustic neuroma only affects one person in every 100,000 in the population. This means that the often complex surgery used to treat it is a specialised procedure that only a few surgeons in the UK have sufficient experience to carry out.
Acoustic Neuroma SurgeryAn operation to remove an acoustic neuroma is a specialised procedure, as it involves surgery inside the inner ear, and sometimes inside the skull, depending on the exact location of the tumour. It is important to remove the growth, as it if continues to grow it will cause the symptoms of hearing loss, tinnitus and balance problems to get worse over time.
Once the tumour has reached a size where symptoms are becoming problematic, surgery may be the only choice available. Until that point is reached, it may be that the surgeon or specialist prefers to keep an eye on the tumour using regular MRI scans, and monitors any worsening of symptoms.
The actual surgery involves microsurgery and neurosurgery, as well as a general anaesthetic. It also carries substantial risks, as the operation can damage structures within the ear, and there are a small proportion of people who experience long-term worsening of their symptoms despite their tumour being removed successfully.
Success Rates And Acoustic Neuroma SurgeryBetween 30-65% of people who have surgery to remove their acoustic neuroma usually experience a good outcome. Because the tumour is benign, it does not invade other tissues, and so can be completely removed from the acoustic nerve. If this is done before damage to the nerve becomes permanent, it is likely that symptoms will start to disappear but this could take several weeks or months. Compression of the acoustic nerve takes time to resolve and people need regular check-ups to follow their progress.
The benign nature of the tumour means that it does not spread, but it can recur if not completely removed. It is slow growing, however, so once surgery has been done, it is unlikely that any recurrence of the tumour will cause problems for several years.