Abstract: In a surgically implantable shunt system for venting cerebrospinal fluid in the treatment of hydrocephaly, a valve and the method of testing it are disclosed. The valve comprises an elongate hollow valve body into which a flat plate tightly fits, partitioning the valve body into an outlet and an inlet chamber. The flat plate has a circular aperture connecting the chambers and upon which rests a spherical ball of diameter larger than the aperture. A flat spring biases the ball against the circular periphery of the aperture creating a circular seal and providing a precisely defined back pressure, low hysteresis and low susceptibility to bridging by debris. Testing for leakage is accomplished by illuminating with light of a suitable frequency the aperture with ball seated and detecting any light transmitted therethrough.

Abstract: In a surgically implantable shunt system for venting cerebrospinal fluid in the treatment of hydrocephaly, a valve and the method of testing it are disclosed. The valve comprises an elongate hollow valve body into which a flat plate tightly fits, partitioning the valve body into an outlet and an inlet chamber. The flat plate has a circular aperture connecting the chambers and upon which rests a spherical ball of diameter larger than the aperture. A flat spring biases the ball against the circular periphery of the aperture creating a circular seal and providing a precisely defined back pressure, low hysteresis and low susceptiblity to bridging by debris. Testing for leakage is accomplished by illuminating with light of a suitable frequency the aperture with ball seated and detecting any light transmitted therethrough.

Abstract: In the method of treating ascites disclosed herein, an intraperitoneal inlet tube is connected to an implanted jugular catheter through a valving unit including a pair of one-way valve units which are connected in series through a flexible intermediate chamber to another pair of one-way valve units. The flexible chamber is surgically secured near the surface of the patient's abdomen or chest, preferably over the sternum, so that, by manual pressure, the patient can periodically deform the conduit thereby to effect pumping of the ascites fluid.

Abstract: The servo valve disclosed herein is rendered essentially insensitive to changes in pressure across the valving element by providing spring biasing of the valving element which is controlled by a diaphragm exposed to the inlet and outlet pressures. In a particular embodiment, the diaphragm is spring biased and the spring rates for the diaphragm and the valve element are selected in such proportion that the change in biasing force on the valve element exactly compensates for any change in inlet pressure. Therefore, the valve remains closed for any inlet pressure, unless the bias on the spring rates is unbalanced by a signal coming from a sensor.

Abstract: In the implantable pressure sensor disclosed herein, a radio-opaque liquid is contained within a resiliently compressible vessel of a silicone rubber, the volume of liquid actually contained within the vessel being then variable as a function of the pressure or force applied to the vessel. The silicone rubber is rendered impervious to the radio-opaque liquid by a treatment which involves expandng and saturating the cured silicone rubber with a mixture of a hydrocarbon solvent such as heptane containing a dissolved wax such as beeswax. The solvent expands and saturates the silicone rubber, carrying beeswax into the silicone rubber. When the solvent evaporates, the beeswax is then trapped within the interstices of the silicone rubber, under tension.