Cerebellopontine Angle (CPA) Tumors

We, as brain surgeons, call the place as “the angle”, which is located behind our ears, where our cerebrum neighbors to the cerebellum, and which has the eight cranial nerve coming from brain stem leading to ear structures (n stato-acusticus). Also in this region are the fifth, seventh, ninth, tenth, eleventh and twelfth cranial nerves. In this region, the benign tumor that develops from the nerve of the balancing and hearing organ causes problems for patients and surgeons. There are also other tumors that grow in this region (meningioma, epidermoid etc.), however the most common one is the tumor developing from the Schwan cells of the eight nerve, which is called acoustic neuroma (vestibular schwannoma).

Who can get acoustic neuroma?

It can occur in anyone regardless of sex; however, it may develop more frequently and sometimes bilaterally in those who have some hereditary diseases (Neurofibromatosis, VHL, etc.)

How does acoustic neuroma develop?

It develops when nerve sheath cells grow out of the chain of command. It starts from inside the nerve channel, which has the ears, and it spreads out as it grows, developing towards the surface of the neighboring brain stem.

What are the symptoms of acoustic neuroma?

It may produce no symptom until it reaches a particular size, because the structure it develops over is not a component of the nerve but the sheath protecting the nerve. When tumor presses on the nerve, the first symptom would be ringing in the ear and loss of hearing. In early stages, patient can not hear the high pitched sounds on the phone and misses some parts of speech. As mass grows further, sense of hearing is also lost gradually, leading finally to deafness. There is not always a proportion between the size and the damage of the tumor. While a tumor of 1 cm may cause loss of hearing in some patients, a tumor of 3 cm may not produce any harm on hearing. This fact affects the type and duration of the treatment to be recommended to patients, causing controversial scenarios for doctors and patients.

As the tumor grows in size, it leads to numbness in the face when it presses on the adjacent fifth nerve, and it leads to facial paralysis when it presses on the seventh nerve, and it leads to weakness and problems in balancing, if it grows even further. IF NOT TREATED, IT KILLS.

What treatment method is applied by Dr. Yunus Aydın for acoustic neuroma?

The surgery must be carried out by surgeons who have been educated by the surgeons with experience on the subject and have gained experience by performing surgeries on a particular number of patients. Humans as part of their nature do not want to pay for one’s mistake, which means it would not suffice to get rid of the tumor but patient should not have any loss in body. The priority here in terms of surgery is the vital situation, that is, to prevent a death or a serious disability.

Only a particular amount of experience in the field can achieve this; however it is the most important purpose of the surgeon during the surgery to protect the integrity of the seventh nerve that reaches the face. The experience helps protect the integrity of this nerve, however not all nerves rescued by surgeons start functioning immediately, taking some time to return to a properly functioning state. It is also important to protect the pairs of the hinder brain (medulla). It is the shared purpose of surgeon and patient to have the tumor completely removed, causing also minimum damage. Certainly, the utmost aim is to rescue the brain stem from the compression and remove the death risk.

What are the alternative treatment methods for acoustic neuroma?

It is an alternative method to burn the tumor with gamma ray in the cases where tumor does not allow for surgery, or the tumor is so small but growing. I personally would not recommend an application other than monitoring for the patients with “hearing ability” at a working level and with a small tumor (up to two centimeters). As for the senior patients, if the tumor is not large enough or if the tumor is not producing any clinical symptom, monitoring only or the gamma ray might be recommended. The most difficult cases are the ones that have tumors on both sides. The risks and benefits in such cases should be decided by having a discussion with the patients about those issues.

What if acoustic neuroma is not treated?

The large tumors which are not treated may cause serious disabilities at the early stage, which may then be followed by death.

Post-op course in acoustic neuroma

If, there is no postoperative facial paralysis or damage on any other cranial nerves, patient is monitored under intensive care for 1 day and stays for 3-4 days at the hospital and can then leave. If there is facial paralysis, it is of vital importance to protect the eyes, that is, the cornea. Since the eyelids are not closing and eyelids can not clean the cornea like the wipers of a car, the cornea will dry up and lose transparency and vision is affected. To prevent this and protect the eyes, the following can be performed: close eyes with pomades during the night and artificial tears during the day, and suture the outer half of the eyelid (tarsorrhaphy ) with support from an ophthalmologist. If the nerve is protected, there will be no need for such precautions after some time (this may mean months or years).

A few weeks after the surgery, a MRI scan of the brain with contrast medium is produced and checked whether or not the tumor has been removed completely. If there are remnants, it should be monitored on a yearly basis to see its pace of growth, which might then either undergo another surgery or be subjected to gamma ray. I personally do not use gamma ray unless I have to.