Recent progress in surgery of malignant gliomas in and near eloquent cortical areas

Abstract

Goal of malignant glioma surgery is to maximally resect the tumor with minimum neurological dysfunction, giving the patients a chance to survive much longer with keeping good quality of life. When malignant gliomas are located in eloquent cortical areas (EA) such as motor and language cortices, multi-modal assistant systems for surgery are essential to carry out the glioma surgery with maximal resection and minimal neurological deficit. These systems include image-guided navigation, photodynamic tumor detection, and functional monitoring including awake surgery. In the image-guided navigation, various devices have been introduced into the navigation system to perform a real-time navigation that enables to correct displacement of structures induced by brain shift. In addition to US-linked navigation, intraoperative MRI has become available to update the images of MRI and DTI. Photodynamic detection with 5-ALA has highly contributed to resect tumors to the maximal extent.However, a novel quantitative method to detect the fluorescence in the surrounding tumor cells will be needed to overcome tumor invasion. Functional monitoring such as cortical and subcortical stimulation is essential to maintain the important neurological functions including motor and language activity. Recently, subcortical stimulation with the navigation of fiber tractography has been widely used to more exactly detect the location of subcortical neuronal fibers. With using these multi-modal assistant systems, we operated on 74 patients with GBM, including 25 patients in EA. Extent of resection and postoperative KPS in patients with EA GBM did not differ from those in patients with non-EA GBM. The EA-GBM patients also showed overall survival as long as the non-EA-GBM patients.