Acoustic neuroma is a benign (non-cancerous) tumour that develops on the eighth cranial nerve (this nerve connects the ear to the brain). Treatment of acoustic neuroma depends on many factors such as your age, symptoms, the size of the tumour, pattern of tumour growth and your hearing ability at the time of diagnosis.
Aims of treatment for acoustic neuroma include:
- Preserving hearing ability in the affected ear.
- Control of tumour growth (by surgical removal of the tumour or by controlling its progression).
- Preventing injury to other nerves (facial and trigeminal) and brain tissue.
Preservation of hearing is considered to be the most important goal while treating and hence it may determine the treatment option chosen. Hearing ability of the patient is best preserved if the tumour is treated when it is very small. With increased use of MRI scan, many cases of acoustic neuroma are diagnosed at a very early stage when they are still small and hearing loss is mild. Loss of hearing in the affected ear before surgery is permanent and does not improve following surgery. Large tumours may cause permanent and complete loss in hearing. People with large tumour, which presses on the brainstem, undergo surgeries that idealise the reduction of increased intracranial pressure (due to accumulation of cerebrospinal fluid in the brain). Hearing preservation is considered secondary in these patients.
Treatment options for acoustic neuromas include:
- Observation ("watching and waiting").
- Tumour excision by microsurgery.
- Radio surgery.
Observation ("watching and waiting"): Older people (more than 65 years) who have small tumours with few or no symptoms, the tumour may be observed over a period of time until further symptoms develop. During the observation period, periodic MRIs and hearing tests are conducted every six to 12 months to monitor the progress of the tumour. If no significant increase in the size or symptoms occurs, observation is continued. If the tumour shows a significant increase in size or causes progressive loss in hearing or other difficulties, treatment becomes necessary. Observation is usually not preferred in younger patients due to the risk of increase in hearing loss if the tumour is not treated and increase in tumour size (this makes treatment more difficult and challenging).
Stereotactic radiosurgery: Stereotactic radiosurgery, such as gamma-knife radio surgery, has been of significant important in the treatment of acoustic neuroma. This surgery allows the doctors to deliver radiation precisely to the growth area without making an incision. It can be performed in people with a small tumour, for residual tumours (portions of a tumour that standard surgery cannot remove without damaging brain tissue) or if you are not fit for surgery.
Surgical removal: Aim of surgical treatment is to remove the tumour, preserve the nerves to the face (facial nerve and trigeminal nerve) and preserve hearing as much as possible. Several techniques are used for removing an acoustic neuroma. The surgery is done under general anesthesia and you may have to stay for four to six days after surgery in the hospital. Surgery can cause a number of complications such as:
- Worsening of symptoms if a nerve or brain tissue is injured during the operation.
- Leakage of cerebrospinal fluid from the surgical wound.
- Hearing loss.
- Facial weakness.
- Ringing in the ear.
- Balance problems.
- Persistent headache.