Helping Preserve Critical Brain Functions
To prepare for surgeries that target brain tumors or epilepsy, or for placement of devices such as a deep brain stimulation (DBS) implant, "awake" craniotomy is performed to determine which areas in the brain are responsible for certain functions. In this procedure, surgeons electrically stimulate regions of the brain while the patient is awake to create a map of areas that should be avoided during surgery, such as areas that govern speech and movement. This painless, but major, open brain surgery can lead to excellent outcomes by preserving critical brain functions.
Because the brain itself does not sense pain directly, an awake craniotomy can be performed while the patient is under local anesthesia. Awake craniotomy requires temporary removal of a portion of the skull to allow the surgeon access to the outer portion of the brain, or cerebral cortex. Because he or she is conscious during the procedure, the patient can report sensations in response to stimulation of specific brain areas. Sensations can be as specific as seeing an image (in response to stimulation of the visual cortex), to a feeling of déjà vu, to the movement of an arm or leg.
These verbal reports and physical clues allow the surgeon to carefully plot a three-dimensional map of the brain and to pinpoint areas of disease or injury. Subsequent surgery can then minimize any damage to the brain that might compromise normal function.