Parasagittal Tumors (interhemispheric, tentorial opening, etc.)

Removal of meningioma is the main method of treating benign or malignant meningiomas. Most of the experts use radical surgery or radiation therapy to remove meningiomas.

Meningioma resection is divided into:

• total (whole tumor is removed);
• subtotal or partial (only a part of tumor is removed).

The type of therapy depends on the size of the tumor, its location, the age of a patient and the presence of pathologies.

There are 2 main methods of meningioma treatment:

• Stereotactic radiosurgery used for difficult access to the tumor and close connection of meningioma with vessels, nerve trunks, sinuses of the brain;
• Surgical removal used in cases of the big size of meningioma (more than 3.5cm in diameter).

Stereotactic Radiosurgery

Radiosurgery is a medical procedure used for destroying of tumors or suspending their functioning by means of a single irradiation with a high dose of ionizing radiation.

Radiosurgery has two main advantages:

1. Irradiation affects the meningioma from different directions (tumor receives the maximum possible dose of radiation)
2. Radiosurgery is non-invasive (treatment of a tumor does not require breaking the integrity of the head tissue and opening the cranium).

The contraindication for radiosurgery is the inability to operate brain tumors over 3.5 cm in diameter. The effectiveness of stereotactic radiosurgery is very high: about 95% of meningiomas stop their growth after a single procedure or a small course of treatment.

The main radiotherapeutic / radiosurgical units are:

• GammaKnife;
• CyberKnife;
• TrueBeam.

Advantages and disadvantages of meningioma removal with the help of the GammaKnife

• designed for non-invasive brain surgery (without the use of a scalpel);
• has a frame based system for immobilization with radiation sources, which can causeside such effects of gamma knife surgery for meningioma as headache, nausea and a risk of infection;
• one image of magnetic resonance imaging is used, in contrast to systems that do not use a frame for attaching the head and require constant imaging with CT during treatment, making an additional contribution to excess radiation doses;
• small sizes of collimators protect the body tissues from the effects of radiation and excludes the possibility of treatment of metastases and tumors over 3 cm.

Features of meningioma resection with CyberKnife

• universal method not only for treating the brain, but also for removing the tumor and metastasis throughout the body;
• mega-voltage X-ray radiation from the CyberKnife is four times more powerful than the energy from cobalt used in the GammaKnife;
• CyberKnife is a flexible, frameless system that allows a patient to conduct treatment in one or more sessions. This allows oncologists to choose the safest and most effective course of treatment;
• does not require a frame screwing into the skull for immobilization, which helps to avoid headache, nausea and the risk of infection.

Peculiarities of stereotactic radiosurgery using the TrueBeam system

• Focused radiation beams of the system destroy tumor cells without affecting the surrounding healthy tissues;
• use of a metal frame that is bolted to the skull bones of a patient is unnecessary;
• opportunity of fractional irradiation (treatment is divided into 2-5 small sessions, which makes possible to safely treat large meningiomas located near important structures, for example, the optic nerve);
• TrueBeam system is equipped with modern medical imaging devices that allow a radiologist to monitor the tumor behavior in real time;
• During visualization of pathological formations, the technology of cone-beam computed tomography (CT) is used. This method of visualization makes possible to reduce the radiation load on the patient's body by 25%.

Surgical treatment of meningiom

There are 2 indications for surgical removal of meningioma:

• If the tumor is in the area of the brain that is available for surgery
• If the tumor over 3.5 cm in diameter.

Endoscopic intervention is the minimally invasive method of meningioma removal, when the tumor is removed without opening the skull with endoscopic instruments. Removal of meningioma through transnasal access is most often used. The method is the most effective in combination with intraoperative MRI and nerve navigation systems.

Craniotomy or trepanation of the skull is carried out only if the tumor is located close to the surface. This method provides good visibility of the operating field and allows the removal of large tumors.

For the accurate determination of the type of meningioma and for prescribing the fastest and most effective treatment, a patient should go through the following procedures:

• Blood test;
• Electroencephalogram;
• Angiography;
• MRI - magnetic resonance imaging;
• MRS - magnetic resonance spectroscopy;
• CT - computed tomography;
• biopsy.

The rehabilitation period can range from few weeks to a year. It depends on the method of treatment and the type of operation. The physical and psychological condition of a patient before surgery also affects the postoperative period. The recovery will occur quickly if a patient follows a doctor's prescribed rehabilitation program and takes the necessary medicines.

Consequences after the removal of meningioma depend on tumor localization, prevalence of pathological process and histologic type. Young people have none of consequences after meningioma resection in contrast to elderly patients, who face negative effects much more often.

Consequences after resection of meningioma can be various:

• loss of sight;
• hearing loss;
• sensitivity depression;
• paralysis of extremities;
• lacks of coordination;
• recurrence.

Meningioma recurrence rate after the operation:

• 3% for benign tumors;
• 38% for atypical tumors;
• 78% for malignant tumors.

Also possibility of meningioma recurrence depends on location of a tumor.

• at the cranial vault is 3%;
• in the region of the Turkish saddle is 19%;
• in the region of the body of the sphenoid bone 34% within five years;
• in the cavernous sinus is 60-100%.