of the drainage location within the body. Flexible tubing connects the fluid flow orifice within the diaphragm to the inflow port in the first chamber to maintain the valve seat and the ball seated therein at intracranial pressures. In this arrangement, the ball remains firmly seated within the valve seat as long as the pressure differential across the valve remains at a substantially constant predetermined value. Differences in fluid column height are compensated for by flexing of the diaphragm while the ball remains firmly seated within its valve seat.
In a second embodiment, the valve is again provided within a hermetically sealed housing having first and second chambers. The first chamber is in fluid communication with the inflow port on the valve. The second chamber is in fluid communicationsuitable for cranial implantation and useful in the treatment of hydrocephaly.
It is another object of the present invention to provide a drainage valve useful in the treatment of hydrocephaly and which prevents excess drainage of CSF in the event of normal increases in differential fluid pressures such as when the patient arises from a recumbent position, for example.
These and other objects of the present invention will be more clearly understood by those skilled in the art following a consideration of the remainder of the disclosure, including the detailed description of the preferred embodiments and the appended claims.