Meningiomas are benign tumours developing from the meninges (the membranes surrounding the brain). The meninges form a multi-layered structure enclosing the entire brain and separate the brain and the bones of the skull. They provide extra protection for the brain. Meningiomas can occur anywhere on the meninges. Larger tumours exerting pressure on the brain can cause symptoms. These symptoms depend on the location. They may cause headaches as well as paralyses or epileptic attacks. At the base of the skull, the meninges also enclose cranial nerves, and so meningiomas of the skull base frequently cause cranial nerve disorders such as double vision.
The treatment for meningiomas is generally surgery, but in patients with tumours that are not too large in sensitive areas of the brain, or patients with increased operative risk, treatment with the Gamma Knife can be a gentle, less invasive option with comparable efficacy.
In 90% of patients, Gamma Knife treatment brings tumour growth to a permanent halt. This means that the tumour does not grow any more and in most cases it actually shrinks. Because meningiomas are very slow-growing tumours, the effect of the treatment cannot be assessed until two to three years after treatment. Nevertheless, the symptoms may improve after only a few months.
In the case of very large or refractory meningiomas, Gamma Knife treatment is frequently only a second-line option, e.g.after an operation leaving tumour residues on sensitive structures.