Acoustic neuroma is an intracranial tumor arising from the vestibular part of VIII cranial nerve known as vestibulocochlear nerve. It is a cranial nerve arising from the ventral part of the pons and contains fibers arising from six nuclei of the brain. These nuclei include four vestibular nuclei namely, medial, lateral, ventral and dorsal vestibular nucleus and two cochlear nuclei namely, anterior and posterior cochlear nucleus.
How Do You Get An Acoustic Neuroma?
There are not much specific causative factors known for the origin of acoustic neuroma. The most common cause relatable to acoustic neuroma is idiopathic. Only one environmental factor with definitive association known with an acoustic neuroma is radiation exposure only. Radiation exposure can occur from harmful ultraviolet and other radiations in the sunlight as well as from iatrogenic causes like exposure to X-rays in various body investigations, exposure to radiotherapy for other cancers, etc.
Another factor which is is strongly associated with an acoustic neuroma is genetic syndromic disorder known as neurofibromatosis. It is classified as type 1 and type 2. Although both types can be associated with acoustic neuroma 2 has a more strong relationship with it than type 1. Also, it is generally associated with bilateral acoustic neuroma formation rather than unilateral cases as seen in other causes.
In recent times, mobile phones were suspected to be one of the factors associated with increased incidence and prevalence of acoustic neuroma in the 21st century. But the researches ongoing on it have shown results otherwise. Various studies have not found any relation between the usage of mobile phones and the increased incidence of acoustic neuroma.
Can Acoustic Neuroma Be Cured?
It is a slow-growing, nonmalignant, rare tumor with small size occurring in internal acoustic meatus or at a cerebellopontine angle in the posterior cranial fossa of the skull. It rarely becomes symptomatic and even more rarely requires treatment. The prognosis and the cure rate of the tumor are very high in unilateral cases but it can be slightly more difficult in bilateral cases.
Even if it requires treatment, the tumor is curable in most cases. Surgical treatment has shown, the very good success rate in the complete elimination of the tumor. Medical treatment is not much preferred because of limited success. With the invention of better anesthetic techniques, surgical treatment has become much safer.
Nowadays, with the advent of new technologies in the medical field, a newer treatment based on radiotherapy has proven well in the treatment of acoustic neuroma, it is known as stereotactic radiotherapy[1]. In this treatment, the tumor is precisely located with the help of brain imaging techniques like computed tomography, magnetic resonance imaging, etc. and the dosage of radiotherapy is calculated based upon the size and extent of the tumor. Then the tumor location is marked with the help of a laser and absolute amount of calculated dosage is given with high precision to the tumor. Usually, it requires only one round of it but multiple rounds of the radiotherapy can be given in larger tumors. In cases of failure of stereotactic radiotherapy, the patient can choose for surgical treatment which has a higher rate of success.
Conclusion
There are not many causes known which are directly responsible for acoustic neuroma formation in the brain. Neurofibromatosis type 2 is the only truly known cause for it. Till now the prevalence of the tumor is not very high but various retrospective case-control studies and their analysis are being done for listing the causes and their preventive measures to control the rising incidence of acoustic neuroma.
The tumor has got a high cure rate and good prognosis with positive results of the surgeries devised for the same. Now the treatment of smaller acoustic neuromas is possible with the radiotherapy and without being invasive for the patient. Robotic use helps to demarcate the tumor area with high precision. But it is equally important for the patient to report to the doctor in case of any suspicious symptoms.
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