Insular gliomas represent a group of brain tumors located within the insula, a region of the brain that plays a key role in functions such as emotions, sensory processing, and autonomic control. Due to this location’s intricate anatomy, surrounded by critical structures and white matter tracts, surgical removal of insular gliomas poses significant risks and complexities. To address these challenges, recent literature, including an extensive review by Kuniaki Saito from the Department of Neurosurgery, Kyorin University Faculty of Medicine, has detailed surgical anatomy and operative methodologies intended to optimize patient outcomes.

The insula’s vulnerability and importance to numerous essential neurological pathways have long made surgeons cautious in approaching this region. However, progressive advancement in surgical techniques and an in-depth understanding of the insular cortex’s anatomy have eased this cautiousness. Saito’s work has contributed substantially to this field, with his article “Surgical Anatomy and Operative Technique for Insular Glioma” published in the Japanese journal No Shinkei Geka (Neurological Surgery) in April 2019.

Saito’s article, which appeared in volume 47 issue 4 (pages 405-418), provides a comprehensive overview of the sophisticated approaches needed for safe and effective insular glioma resections. The publication is indexed in the No Shinkei Geka journal with the DOI: 10.11477/mf.1436203954. Furthermore, the work is a significant contribution to the global compendium of neurosurgical techniques aiming to improve surgical outcomes for patients with brain neoplasms.

The paper meticulously describes the intricate surgical anatomy of the insula, emphasizing the critical white matter tracts, vascular structures, and functional areas that surround the region. With visual aid and descriptive terminology, Saito enlightens neurosurgeons on the landmarks necessary for safely navigating the insular cortex during tumor resection.

Insular Glioma: Understanding the Complexity

Insular gliomas can range from low-grade to high-grade malignancies. High-grade insular gliomas are particularly aggressive and carry a worse prognosis. Accurate resection of these tumors is crucial for increasing survival rates but must be balanced with the preservation of neurological function. The proximity of the insula to the basal ganglia, thalamus, and critical vasculature, including the middle cerebral artery, makes surgical intervention in this region a delicate process.

Surgical Approach Innovations

Saito’s publication details several operative techniques for approaching the insula, including transcortical and transsylvian methods. The transcortical approach requires a careful incision through the frontal or temporal cortex, providing direct access to the insula, while the transsylvian approach involves spreading the sylvian fissure to access the insular region.

Neurosurgical advancements, such as intraoperative MRI and brain mapping, have significantly improved the precision of these approaches. Techniques like awake craniotomy, where the patient remains alert during surgery to provide live feedback on brain function, have also proved to be remarkably beneficial in preserving essential neurological structures.

Preoperative and Intraoperative Imaging

Modern neuroimaging technologies have revolutionized preoperative planning and intraoperative navigation for insular gliomas. Techniques like functional MRI (fMRI), diffusion tensor imaging (DTI), and positron emission tomography (PET) allow surgeons to visualize not only the tumor but also the surrounding functional brain areas and white matter tracts.

Saito underscores the importance of these imaging techniques in his publication, explaining their role in developing a precise surgical plan that minimizes risks and maximizes tumor removal. High-resolution imaging facilitates a personalized approach to each patient’s unique anatomy and tumor characteristics.

Outcomes and Postoperative Care

The outcomes of insular glioma surgeries have improved alongside these technical advancements, with increased survival rates and preserved neurological function. Yet, postoperative care is just as critical. Saito discusses in his article the need for a multidisciplinary approach, involving oncologists, neurologists, and physical therapists, amongst others, to ensure a comprehensive rehabilitation program and monitor for potential complications.

Neuroscientific Implications and Future Perspectives

Surgical intervention for insular gliomas not only extends survival but also offers valuable insights into the complex neuronal functions associated with the insula. Research on patients’ preoperative and postoperative neurological performance can provide a wealth of data on the role of the insula in human cognition and behavior.

Looking ahead, there is optimism for future innovations, including enhanced neuro-navigation systems, robotic surgery, and individualized molecular therapies, all of which could lead to even better patient outcomes.


Insular gliomas, lying deep within the critical structures of the brain, offer one of the greatest challenges in neurosurgery. The work of Dr. Kuniaki Saito and colleagues is instrumental in guiding surgical strategy and technique, ultimately aiming to improve the prognosis and quality of life for patients afflicted with these complex tumors. It reflects a commitment to technical excellence and nuanced understanding of the brain’s anatomy and function, reinforcing neurosurgery’s evolution towards safer and more effective tumor resections.


1. Saito K. (2019). Surgical Anatomy and Operative Technique for Insular Glioma. No Shinkei Geka. Neurological Surgery, 47(4), 405-418. DOI: 10.11477/mf.1436203954

2. Sanai N., Polley M.Y., McDermott M.W., Parsa A.T., Berger M.S. (2011). An extent of resection threshold for newly diagnosed glioblastomas. Journal of Neurosurgery, 115(1), 3-8.

3. Hervey-Jumper S.L., Berger M.S. (2016). Insular glioma resection: Assessment of patient morbidity, survival, and tumor progression. Journal of Neurosurgery, 124(1), 1-10.

4. Duffau H. (2009). Stimulation mapping of white matter tracts to study brain functional connectivity. Nature Reviews Neurology, 5(5), 255-265.

5. Ius T., Isola M., Budai R., Pauletto G., Tomasino B., Fadiga L., Skrap M. (2012). Low-grade glioma surgery in eloquent areas: Volumetric analysis of extent of resection and its impact on overall survival. A single-institution experience in 190 patients. Journal of Neurosurgery, 117(6), 1039-1052.


1. Insular Glioma Surgery
2. Neurosurgical Techniques
3. Brain Tumor Resection
4. Neuroanatomy of Insula
5. Intraoperative Neuroimaging