Nasser Institute


Acoustic Neuromas


The acoustic neuroma is a benign (non-cancer) tumour. It grows from the covering of one of the balance nerves. The acoustic neuroma affects roughly 9.5

people per million. While the acoustic neuroma grows from a balance nerve it is called acoustic because the commonest first symptom is deafness.


The diagnosis of acoustic neuroma is easily made with special hearing tests and the imaging technique MRI. The Gamma Knife has been used to treat

acoustic neuromas for over 25 years and has a long record of controlling the growth of smaller acoustic neuromas without the discomfort and complications of surgery.

The patients suffer deafness and noises in the ear and balance problems. These symptoms mostly do not get better with treatment but the tumour is controlled and does not then develop into a danger.



Over time the annoying symptoms will improve though not the deafness. The biggest problem is to avoid a facial palsy with loss of movement in the

face. This is a common complication after surgery. It is not seen in ther series of over 500 patients and that is in keeping with the experience of others.


The below images shows necrosis. This refers to a change on the images where the centre of the tumour ceases to take up contrast on MRI.

It is a consistent indicator that the tumour is controlled. Shrinkage occurs later and in our material the frequency of shrinkage is clearly related to the duration of follow



The image shows the tumour on the day of treatment and 6 months later. The loss of

contrast enhancement is easy to see in the image on the right. This change will disappear

with time so that the tumour returns to the appearance on the left. Nonetheless,

the presence of this finding is virtually a guarantee that the tumour is controlled. Later,

over the months and years to follow it will also shrink as we are seeing in our patients.