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.

Most brain tumors remain incurable. Progress in clinical trials to identify better treatments has been slow. We hypothesize that longitudinal CSF access can provide insights regarding tumor identity, behavior and the efficacy of candidate therapies. Although multiple studies have evaluated CSF from patients with brain tumors, very few have collected CSF at multiple timepoints throughout the course of disease. However, multiple samples over time are needed to determine if candidate biomarkers accurately reflect the evolution of disease. CSF is typically obtained via lumbar puncture which is inconvenient and often uncomfortable. This protocol will evaluate the safety and feasibility of placing Ommaya reservoirs at the time of surgery. It is anticipated that reducing barriers to CSF access through placement of an Ommaya reservoir may expedite brain tumor research and facilitate the development of individualized treatment strategies.

An Ommaya Reservoir will be placed during a planned brain tumor operation. Following the routine portion of the planned procedure, the Ommaya reservoir will be placed under the scalp with the catheter tip placed either within the ventricle or the resection cavity. Presence of the Ommaya reservoir will enable CSF to be easily accessed at any time in the future. It is expected that CSF will be collected at 2 or more timepoints. CSF will be stored in the Mayo Clinic neuro-oncology biorepository and made available in a de-identified manner for multiple research projects. The patient and his/her provider(s) may take advantage of the Ommaya reservoir and/or banked CSF samples to facilitate participation in any relevant IRB-approved research study(s), and/or to facilitate individualized management. The details of each time the Ommaya is accessed will be documented as part of this trial.

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 <18 years old.
• Patients who are not appropriate candidates for surgery due to current or past medical history or uncontrolled concurrent illness.
• Prior history of any wound infection
• Any patient who the surgeon feels is not an optimal candidate for Ommaya reservoir placement. Such reasons could (but need not necessarily) include factors related to surgical anatomy, clinical evidence of significant immunosuppression, and/or elevated risk of wound infection due to diabetes, smoking history, morbid obesity, or any other concerns.
• Any patient for whom a clinical contraindication exists to a lumbar puncture (LP) will be excluded from the LP portion of this protocol, but would still be eligible for an Ommaya reservoir if they meet the inclusion criteria of the study. For example, a patient with a large posterior fossa mass lesion at risk of herniation, or a patient with coagulopathy, or other contraindication to lumbar puncture would not be eligible to participate via use of lumbar puncture for CSF access

Protocol details and individualized de-identified patient data will be provided as supplemental files in the resulting publication. Any additional information not otherwise provided may be requested from the primary investigator.

Any time after publication.

Requests will be honored that could help advance the care of patients with brain tumors.