The Cerebrospinal Fluid (CSF) Physiologic Controller (20) is an implantable active battery-operated device that is microprocessor controlled via algorithms stored in its memory. It is a multi-mode drainage system that contains at least two flow paths : a low resistance flow path (27) for when the patient is in the supine or substantially supine position and a flow path (25) containing a programmable variable check valve (26) to prevent over-drainage when the patient is in the upright or substantially upright position.
