RecruitingProcedureFeasibility of Intraoperative Microdialysis During Neurosurgery for Central Nervous System MalignanciesThis clinical trial evaluates the use of microdialysis catheters during surgery to collect biomarkers, and studies the feasibility of intraoperative microdialysis during neurosurgery for central nervous system malignancies. A biomarker is a measurable indicator of the severity or presence of disease state. Information collected in this study may help doctors to develop new strategies to better diagnose, monitor, and treat brain tumors.