Abstract: An implantable valve for controlling the passage of cerebrospinal fluid (CSF) from a ventricle of the brain to a suitable drainage location in the body includes a movable diaphragm responsive to pressure differentials between the ventricle and the drainage location. When the pressure differential is below a minimum threshold level, the valve is closed and CSF flow is prevented. When the pressure differential increases beyond the minimum threshold, the valve operates in a constant pressure mode to maintain a first predetermined CSF pressure differential across the valve. When the differential pressure increases beyond an intermediate threshold level, the valve operates in a constant flow mode to maintain a desired constant CSF flow rate through the valve. When the pressure differential increases beyond a maximum threshold level, the valve operates in a constant pressure mode to maintain a second predetermined CSF pressure differential across the valve.

Abstract: An implantable valve for controlling the passage of cerebrospinal fluid (CSF) from a ventricle of the brain to a suitable drainage location in the body includes a movable diaphragm, one side of which is in the pressure communication with the drainage location of the body, and the other side of which is in pressure communication with the ventricular spaces of the brain. A valve assembly, actuable by displacement of the diaphragm in response to applied pressure differentials, regulates passage of CSF from the ventricular spaces to the drainage location. When the pressure differential falls below a minimum threshold level, the valve is closed to prevent fluid flow. When the pressure differential increases beyond the threshold, the valve operates in a constant pressure mode to maintain a first predetermined pressure differential across the valve.