Acoustic neuroma treatment in India
Acoustic Neuroma is a non-cancerous tumour occurring in the cranial nerve supplying the ear. It is also called as vestibular schwannoma as it occurs in the Schwann cells of the vestibule-cochlear nerve. The vestibulocochlear nerve passes through an opening in the cranium called the internal auditory canal on its way from the brain. An acoustic neuroma almost always originate in that part of the nerve before it exits the cranium. Hence an acoustic neuroma is referred to as an intracranial tumour.
About six to seven percent of all intracranial tumors are acoustic neuromas. Being a non malignant tumor they don’t metastase or spread to other parts of the body. Similarly it is also a non-invasive tumor and never invades the brain. The symptoms of the tumor occur due to the pressure it exerts in the brain as it increases in size. The pressure it exerts on the brain stem and cerebellum can cause various symptoms.
Acoustic neuromas are slow growing tumors. At times the tumor remains small and stops growing. If it remains small, no treatment is required. Treatment is necessary only when the tumour starts exerting pressure on the brain and other cranial nerves. Acoustic neuromas are typed as medial tumors and lateral tumors according to its location with respect to the structures of the brain. Similarly a tumour less than 1.5 centimetres in size is termed as a small tumour. Those between 1.5 to 2.5 centimetres termed as medium tumour and above 2.5 centimetres as large tumours.
What causes acoustic neuroma?
The exact cause of acoustic neuroma is not known. Almost ninety percent of cases occur without any reason whatsoever. A few risk factors that may increase the chance of developing the condition have been identified. A vast majority of acoustic neuroma sufferers are in the age group of thirty to sixty. A family history of a genetic condition called neurofibromatosis type 2 may increase the chance of acoustic neuroma. In such situations the tumour occurs in both the vestibulocochlear nerve. Exposure to radiation in the head and neck region during childhood may increase the risk.
Acoustic neuroma symptoms-
The signs and symptoms of acoustic neuroma primarily arise due to its effect on the vestibulo cochlear nerve from where it originates. Vestibulo-cochlear nerve is connected with hearing and maintaining the balance of the body. Hence the major symptoms of acoustic neuroma are related to problems with ear and body balance.
The signs and symptoms of acoustic neuroma may also arise due to its pressure effects on the brain. The tumour can also exert pressure on the facial nerve and the trigeminal nerve that lies close to it. The pressure effects on the facial nerve can cause a loss of function of the muscles of facial expression. Similar pressure effects on the trigeminal nerve can cause a loss of sensation in the face.
The intensity of symptoms depends mostly on the size of the tumor. Small tumours cause fewer symptoms and large tumours cause intense symptoms. Some of the most commonly identified symptoms are:
• Gradual loss of hearing, mostly limited to one ear
• Sudden loss of hearing in rare cases
• Ringing sensation or tinnitus in the affected ear
• Vertigo or dizziness
• Feeling of unsteadiness while walking or standing up
• A loss of body balance
• Numbness of one side of the face
• Weakness on one side of the face
• Large tumours may cause headache, nausea and vomiting due to pressure on the brain
• Very rarely vision problems or disorientation can occur due to the effects on the brain
Acoustic neuroma diagnosis-
A preliminary diagnosis of acoustic neuroma is made by evaluating the symptoms. A hearing test or audiometry is done to assess the level of hearing loss. X-rays, CT and MRI scans are done to assess the exact location and size of the tumour.
Other conditions with similar symptoms to those of acoustic neuroma include-
• Meniere's disease
Acoustic neuroma treatment in India
Acoustic neuroma treatment surgery and radiation therapy is available in all major hospitals in India. A surgical treatment for acoustic neuroma needs about six to seven days of hospitalisation. A longer hospital stay may be necessary in certain situations. The preliminary diagnostic tests may require about a couple of days. The review will be done after ten days post surgery. Those coming for acoustic neuroma treatement in India should be ready to spend about three weeks in the country.
Acoustic neuroma treatment options:
The major treatment options for acoustic neuroma are surgery and radiation. But a small tumour not causing any symptom is best left alone. Such tumours are usually picked up during imaging studies like X ray, CT or MRI scans done for other reasons. A watchful surveillance and periodic reviews are done to look for any increase in size. Treatment is contemplated only if the tumour starts growing beyond a certain size.
Acoustic neuroma surgery:
Surgery is the best treatment option that offers the chance of total cure, if complete removal is possible. Surgery is also the best option for patients with large tumours. Radiation is also best avoided in young patients because of an increased risk of long term side effects. The main drawback of surgery is the increased risk of hearing loss and facial nerve paralysis. The major complication includes cerebrospinal fluid leak and meningitis.
Various surgical treatments are available for acoustic neuroma. The technique depends on the size of the tumor, its proximity to sensitive structures, hearing status among other factors. The aim of surgery is to remove the tumor without causing any damage to the facial nerve. Preservation of hearing is also accorded importance whenever possible.
It is not always possible to remove the tumor completely without causing damage to the brainstem or the facial nerve. In such a situation as much of the tumor as possible is removed. The surgeon will take a call regarding the exact amount of tumor to be removed during the process of surgery. This depends on the degree of chances of injuring the facial nerve or brain stem. Inadvertent injury to the meninges can result in a leakage of cerebro spinal fluid and cause meningitis. These factors are also taken into consideration by the surgeon. Post- surgical radiation treatment is recommended if a part of the tumor is not removed.
The surgery is done under general anaesthesia. The surgical team will comprise of a neurosurgeon, head and neck surgeon, neurologist among others. The head and neck surgeon usually creates access for the neurosurgeons to micro dissect the tumor. The duration of surgery may range from four hours to eight hours. Under exceptional circumstances the surgery may take even fifteen to twenty hours.
Radiation treatment for acoustic neuroma:
There are two major radiation treatments for acoustic neuroma.
Stereo tactic radio surgery (SRS):
The treatment does not involve any surgery as the name suggests. The treatment involves the precise delivery of a high dose of radiation. The complications are less compared to surgery. The treatment is painless and will be over in a single day, holds lower risk of complications, takes a single day and is nearly painless. The major risks are hearing loss and facial paralysis. The treatment is not effective for large tumors that are compressing the brainstem.
Stereotactic radiotherapy (SRT)
This is another type of radiation therapy. The major advantage is that the treatment is painless and causes lesser complications as compared to surgery and SRT. The main disadvantage is the duration of treatment. The procedure may take up to thirty sittings spread over six weeks.
SRT may be a better choice than SRS for acoustic neuromas if hearing loss and facial paralysis are to be avoided. SRT delivers precise stereotactic radiation divided into multiple smaller doses called fractionation. Fractionation helps reduce the risk of radiation damage to the brainstem and cranial nerve.
Complications of treatment may include:
• Leakage of cerebrospinal fluid through the surgical wound
• Hearing loss
• Facial paralysis, weakness or numbness
• Ringing sensation in the ear or tinnitus
• Balance problems
• Persistent headache
•Stroke or brain bleeding
Do's and Don’ts after treatment
A patient after acoustic neuroma surgery or radiation treatment needs to take proper rest as advised. Wound care is of primary importance. Care should be taken to prevent any infection of the wound. Any symptoms like severe headache or vomiting may be indicative of meningitis and should be dealt with as an emergency. Strenuous exercise should be avoided. Precaution should be taken to prevent the formation of blood clots in the legs.