Microsurgery of Insular Gliomas: Part I—Surgical Anatomy of the Sylvian Cistern

Morphometric analysis of the main brain sulci and clinical implications: Radiological and cadaveric study

Objective

Sulci and gyri of the cerebrum can be easily identified with the aid of radiology but are difficult to locate during surgical operations, owing to anatomical variations and the surgical approach of the sulci through a small aperture. Therefore, this study was performed to locate the main sulci of the brain by using various anatomical landmarks in cadaveric brain specimens and CT scan images.

Methods

In 31 cadaveric brain specimens (17 right and 14 left hemispheres) from people of unknown sex, 21 parameters associated with important sulci of the brain were studied. CT scan images for 150 patients in three age groups were examined. The patient IDs were categorized into 50 patients in each of the following age groups: 20-40 yr, 41-60 yr and 61-80 yr. Ten parameters were studied. The data were statistically analyzed in SPSS software.

Results

In the cadaveric brain specimens, comparisons of right and left hemispheres indicated that only the posterior part of the calcarine sulcus showed a significant difference (p = 0.0394). In CT scans within each age group, comparison of the right and left sides in males and females showed significant differences for many parameters (e.g., calcarine sulcus to occipital pole: right p = 0.0025; left p = 0.0009). Comparisons between male and female parameters also showed significant differences.

Conclusion

This study aids in identifying the important functional areas of the brain situated near the sulci, given that the sulci are connected to the gyral functions and act as a barrier for the gyri. The findings may facilitate neurosurgery operations.

Integration of Microanatomy, Neuronavigation, Dynamic Neurophysiologic Monitoring, and Intraoperative Multimodality Imaging for the Safe Removal of an Insular Glioma: 2-Dimensional Operative Video

Insular gliomas are located amongst myriad critical neurovascular structures, including lenticulostriate vessels, long insular perforators, putamen, internal capsule, frontal and temporal opercula, and key fasciculi.1-6 Each of these critical structures engenders key function of the brain, which must be preserved. Although anatomic knowledge remains the cornerstone of insular glioma surgery, novel tools have been developed to aid the surgeon in identifying and preserving these essential structures. Modern surgery of the insular glioma calls for seamless integration of these techniques to maximize the safety and totality of insular glioma resection, which has been shown to improve length of survival and seizure control, while reducing risk of tumor transformation.7-10 Neuronavigation can be used to help plan the craniotomy to achieve adequate exposure and assist during tumor resection. Brain "shift" can be corrected by re-registration following intraoperative magnetic resonance imaging (MRI). Interval ultrasound imaging reflects real-time progressive tumor resection. Dynamic neurophysiologic monitoring using thresholding techniques guides the surgeon as he resects tumor at its depth and posterior pole-close to the internal capsule. Intraoperative magnetic resonance imaging depicts residual infiltrative tumor that may require additional resection. The patient is a 33-yr-old woman with progressive growth of a right insular tumor and has consented to surgery, photography, and video recording.  Figure at 1:57, © Ossama Al-Mefty, used with permission.