Awake brain mapping by direct cortical stimulation; technical note to get higher resection rate and low morbidity in low-grade glioma patients

Abstract

Introduction: Direct cortical stimulation has been used for brain mapping and localization of eloquent areas in awake patients. This simplified technique is to provide the positive areas, which can be preserved if the tumor or lesions are involved eloquent areas. Objective: The main objective of this study is to determine whether direct cortical stimulation in awake brain mapping for low-grade glioma patients increases the rate of resection or not. Method: The authors present a retrospective study between 2020 to 2022 that includes 35 cases in a single center, to get higher resection rate, and their consequences in awake craniotomy in low-grade glioma patients. Here, two neurosurgeons were involved and the minimum follow-up was 12 months. Results: The authors achieved 80% removal of tumors. To get higher resection rate we emphasized negative mapping with prior anatomical analysis to understand functional realignment. Stimulation-related complications will be thoroughly discussed with a potential future direction to minimize the issues. The authors used PROMIS score to measure patients physical and mental health status and kernofsky score to measure performance status before and after successful surgery. The authors found three cases of transient deficit in repetitive stimulation. Repeated stimulation to identify the eloquent areas with low voltage frequency is a good option. Numbness in the face related to stimulation may continue for 6 weeks. Conclusion: Functional realignment in shifted brain and edema can be seen while doing cortical and subcortical stimulation. Most of the stimulation from low to high for language mapping may vary from patient to patient. For safe removal of low-grade glioma a steep learning curve is needed to find out the negative areas, though the authors emphasize positive mapping of areas to secure the maximum eloquence.