The treatment of an acoustic neuroma (a tumour on the VIII Canial nerve, the nerve for hearing) is not straightforward. Because it is a benign tumour, complete removal is the obvious treatment. However, the VIII CrN is at the base of the brain and it is difficult to access the tumour. For years, the surgical access was through a hole (craniectomy) at the base of the skull but over the last 20 years, access has been possible through the temporal bone, i.e. the ear. If the tumour is mostly within the internal ear canal, then the approach through the ear is preferable. With large tumours within the cranium, craniectomy is preferred. Another problem is that the tumour may stretch the VII CrN (facial nerve) around it so that removal of the tumour can result in paralysis of that side of the face. Because of the risks of surgical treatment, focussed X-Rays (radiotherapy) or gamma rays (gamma knife) have been successfully used to treat acoustic neuromas. Focussed radiotherapy is available in Dunedin, but there is no gamma knife in New Zealand. Treatment is decided on the basis of the size of the tumour, its exact location and the fitness of the patient.
This is a benign slow-growing tumour on the 8th cranial nerve, which conducts messages from the cochlear to the brainstem, so that the main symptom is gradually progressive deafness on that side, causing numbness and/or weakness of that side of the face. It may also press on the brainstem causing weakness of the limbs and/or loss of balance.