Neurosurgeons have never simply guessed at where critical areas of the brain begin and end. First and foremost, they are trained to understand the fundamentals of the brain’s anatomy. But boundaries are not always clear, and the growth of a tumor can cause functional areas to shift from their original locations. Large tumors can cause these critical regions to shift dramatically.
To identify functional areas of the brain that should not be harmed, neurosurgeons traditionally have applied a small electrical stimulation with a wand-like instrument during surgery. If a motor area is stimulated, for example, the patient’s hand will move.
Electrical stimulation has had drawbacks, however. “Stimulating the brain with an electrode can cause a seizure,?Dr. McPherson said. “And to accurately identify language areas in some cases we had to keep the patient awake. We also were forced to make a larger opening of the skull and expose more areas.?
The need for electrical stimulation also can lengthen a surgical procedure by 30 to 60 minutes.
While neurosurgeons make the transition to the fMRI-assisted navigation technology, they are continuing to perform brain stimulation to double-check for accuracy. Thus far, Dr. McPherson said, the double checks have confirmed the technology’s accuracy while suggesting that the technology may make brain stimulation unnecessary for many surgeries in the future.
The new BrainLAB equipment also enables physicians to integrate diffusion tensor imaging (DTI), which provides a map of critical white-matter tracts in the brain. “White-matter tracts,?said Dr. Leach, “are like the electrical connections between different parts of a house. If you disrupt that connection, you have no communication between those two areas.?
FMRI scans are performed several days prior to surgery
Source:The Neuroscience Institute