Higher brain function relates to advanced cognitive operations associated with the transmission, expression, understanding, and execution of behavior. In order to preserve higher brain function during neurosurgery, it is essential to know its functional localization and related neural networks. Fiber dissection is the best method for understanding the organization of the fasciculus. The superior longitudinal fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, frontal aslant tract, and cingulum, which control higher brain function, can be observed with fiber dissection. During awake surgery, appropriate tasks can identify the higher brain function-related areas and the fasciculus. It allows us to prevent the possible damage that might occur if the surgery had to have been carried out under general anesthesia. In this way, it has become possible to ensure a preservation of higher brain function during neurosurgery.

  Brainstem cavernous malformation surgery is still challenging because preoperative prediction of deformed/transformed nuclei and conductive tracts inside the brainstem is still difficult. Visualizing the intraoperative neural function of these nuclei and tracts is also challenging.

  To address these issues, we introduced both preoperative virtual surgical simulation using 3D computer graphics to predict the anatomical architecture and to perform intraoperative real-time continuous neurophysiological monitoring to visualize neural function.

  In our surgical strategy, identification of brainstem nuclei and tracts in relation to cavernous malformation using virtual reality three-dimensional fusion images constructed from multimodality images is crucial in choosing the best surgical approach to minimize anatomical nuclei and tract injuries. Intraoperative neural function is visualized as a trend graph, and when it deteriorates, the relevant procedure should not be repeated further, and appropriate recuperation time should be allowed to prevent permanent damage.

  Understanding the anatomical architecture of brainstem cavernous malformations and visualizing real-time neural function on a case-by-case basis is important for surgical strategizing. A representative case is presented here to summarize the key points of surgery.

  The anterior communicating artery has many vascular variations. Multiple or fenestrated anterior communicating arteries are frequently seen. The anterior communicating artery gives rise to three branching arteries. The chiasmatic artery terminates in the superior surface of the optic chiasma. The second branching artery feeds the suprachiasmatic region of the hypothalamus. The third branching artery is the largest and is the subcallosal artery. This artery runs in front of the lamina terminalis and then turns rostrally and dorsally. This artery has no cortical branches and plays an important role in blood supply to the fornix. Injuries to the subcallosal artery can result in severe cognitive and memory dysfunction due to infarction of the associated basal forebrain.

  In recent years, advances have been made in a variety of diagnostic imaging techniques, including three-dimensional digital subtraction angiography (DSA), slab maximum intensity projection (MIP), and fusion imaging of DSA with MRI and CT. These advancements have allowed clinicians to more easily understand the functional micro-vascular anatomy by clarifying the relationship between the brain, cranial nerves, and bone structures. Preoperative precise simulation using these techniques is beneficial not only for endovascular neurosurgeons, but also for general neurosurgeons.

  Herein, we introduce the use of these recent imaging techniques in our daily practice. We routinely performe three-dimensional DSA and slab MIP imaging for the treatment of cerebrovascular disease. Preoperative simulation imaging is then performed using a fusion technique with DSA, MRI, or CT imaging. This regimen helps us to plan an accurate surgical strategy and perform safe surgery.

  Endovascular neurosurgeons, who have extensive knowledge regarding functional vascular anatomy and newly developed diagnostic modalities, may contribute to the strength of both open and endovascular neurosurgery.

  Recently, intracranial electrode implantation using a stereotactic robotic device has been gaining universal popularity in the field of stereotactic neurosurgery. Robot-assisted implantation has advantages of accuracy, decreased procedure time, and a low complication rate. However, to perform the procedure safely, it is necessary to be skilled in surgical planning and technique. Here we present a case of intracranial stereo-electroencephalography (SEEG) using ROSA-guided robotic surgery.

  A 19-year-old male presented with intractable focal seizures with impaired consciousness. Brain MRI showed ischemic ulegyria in the medial right occipital lobe ; FDG-PET was suggestive of extensive abnormalities from the medial/lateral right temporal lobe to the occipital lobe. In this case, we hypothesized that the ischemic ulegyria in the medial occipital lobe was the epileptic focus. We decided to implant intracranial electrodes extensively from the occipital lobe to the temporal lobe and record SEEG to localize the epileptic focus. After loading the patient's imaging datasets into the ROSA software, seven stereotactic trajectories were selected for the electrode insertion route. To avoid hemorrhagic complications, ROSA software was used to map the optimal surgical paths for each electrode insertion. By incorporating the preoperative simulation, we efficiently performed implantation and confirmed electrode locations using ROSA software. Finally, we detected the habitual seizure and ictal discharges originating from the hippocampus on SEEG. To perform the procedure safely and quickly, it is important to accumulate tips and pitfalls to avoid complications.

  Spinal cord swelling with abnormal gadolinium enhancement is a rare preoperative radiological finding in cervical myelopathy patients. Timely cervical decompression can be performed for compressive myelopathy. Here, we report three cases of cervical spondylotic myelopathy. Preoperative magnetic resonance imaging revealed cervical cord swelling with high intensity on T2-weighted imaging and abnormal gadolinium enhancement on MRI. Laminoplasty resulted in marked improvement in the patients' neurological condition, and postoperative MRI revealed gradual regression of the intramedullary lesions within approximately 1 to 3 years. We summarized the course of intramedullary gadolinium enhancement in 16 case reports, including our 3 cases. Postoperative gadolinium enhancement disappeared or remarkably regressed within 1 to 3 years in 61% of cases. The mechanism of spinal cord swelling is considered to be as follows : 1) venous vascular circulation disturbance due to spinal cord compression results in local vascular hypertension at the affected level, and 2) disturbed CSF circulation may play a role in the development of spinal cord edema. Dynamic factors, such as neck hyperextension, may also cause spinal cord edema and gadolinium enhancement.