A mushroom-shaped infusion port, implanted in the ventricles of the brain, to allow access to cerebrospinal fluid (CSF), measurement of CSF pressure, or intrathecal drug administration (e.g., antibiotics, cancer-fighting drugs, or opiates). The reservoir may be used to help treat malignancies or infections of the central nervous system, or control chronic cancer pain. It may occasionally become infected or clogged during use.