Ommaya Reservoir Placement for Brain Tumor Biomarker Access

The purpose of this study is to determine the safety and feasibility of intra-operative Ommaya Reservoir placement during a clinically indicated operation for brain tumor. The Ommaya reservoir will facilitate a longitudinal access to cerebrospinal fluid (CSF) for analysis of potential biomarkers for brain tumor research and individualized monitoring.

Inclusion Criteria: * Age \> 18 years. * Clinical and radiographic evidence suggesting a diagnosis of a brain tumor. * Planned neurosurgical procedure resection of suspected or previously diagnosed brain tumor as part of routine clinical care. * Willing to undergo neurosurgical resection at Mayo Clinic (Rochester, MN). * Willingness of the patient or an authorized representative to provide informed consent * Patient is willing to have their Ommaya sampled on at least 2 future occasions. * Patients is willing to have CSF banked through the neuro-oncology biorepository (requires a separate signature) Exclusion Criteria: * Vulnerable populations including pregnant women, prisoners and individuals \