To attach the stereotactic frame, the neurosurgeon uses local anesthesia on four areas of the head to secure this frame with small screws that attach to the outer part of the skull. Once the frame is in position, the patient receives a CT or MRI scan to locate specific regions of the brain, namely the thalamus, globus pallidus or subthalamic nucleus depending on the kind of surgery that is to be performed. This targeting is done by the neurosurgeon and usually takes about 30 minutes. In the OR, the patient is on the operating bed with the head frame secured to the bed so that the head is still but the patient can move the arms and the legs. An area on the top of the head is shaved and cleaned.
More local anesthesia is placed for incision and a drill is used to make a hole in the skull.
A system is placed on the frame to guide electrodes in the brain. In addition, microelectrode recordings are performed to find the necessary areas of the brain. Electrical stimulation is also used to evaluate the effect on the target symptoms. All this is done to decide the best area of the brain to target. This process usually takes about 1-2 hours.