Medical Health Encyclopedia

In most cancers outside the brain, surgical removal of a tumor usually involves taking out surrounding healthy tissue to be sure all cancer cells are gone. In the brain, however, removing healthy nearby nerve tissue can be as disastrous for the patient as the cancer itself. Special techniques have been developed to allow maximum removal of tumor while protecting healthy brain cells.

Stereotaxy. Stereotaxy has become a useful adjunct to both surgery (stereotactic surgery) and radiotherapy (stereotactic radiotherapy).

Cortical Localization. Cortical localization, or stimulation, uses a probe that passes a tiny electrical current to delicately stimulate a specific area of the brain. This produces a visible response of the body part (such as a twitch in a leg), which the stimulated region of the brain controls. The surgeon then knows to avoid those areas during the operation.

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Image-Guided Surgery. Image guided surgery uses a three-dimensional picture of the patient's brain derived from computed tomography (CT) or magnetic resonance imaging (MRI) scans. An advanced technique called high-field interventional MR imaging (iMRI) is particularly accurate in identifying the tumor, but it is not widely available. The image, with various views of the brain, is displayed on a monitor in the operating room. During surgery, as the surgeon's instrument touches a part of the brain, a camera sends the image to a computer, which calculates the position of the surgical tool and displays it in its proper location on the 3-D image. The surgeon then can look at the monitor and see what structures to avoid.

Magnetic-Tipped Catheters. Neurosurgeons are investigating the use of a technique in which external magnetic fields direct a magnet-tipped flexible catheter to the tumor site through a path that avoids areas of the brain that could cause harm.