Abstract: A valve for the treatment of hydrocephalus of the type including a membrane provided with an aperture and demarcating within a housing an upstream chamber and a downstream chamber. A rod of variable cross section attached to a stopper penetrates into the aperture. According to the invention, the housing includes three parts, a first body, a second body and a base cap. The first body and second body are assembled so as to squeeze the periphery of the membrane. The first body, the stopper and a first face of the membrane form one of the chambers, and the second body, the base cap and the other face of the membrane form the other chamber.

Abstract: A balloon catheter is provided which includes a flexible tube on one end of which a balloon is mounted to be inflated by means of the tube, which balloon has an annular restriction in its middle region in a plane approximately perpendicular to the tube axis. The balloon is produced in the form of a bag inside which the end of the tube is engaged, the opening of the bag being fixed to the outer wall of the tube, and the distal end of the balloon projects beyond the distal tip of the catheter tube to provide a cushioning region at the tip of the catheter assembly. A procedure for making the balloon is also described.

Abstract: A catheter introducer including a cannula, a stylet disposed within the cannula, and means for holding a catheter in close proximity to the cannula and stylet so that the tip of the catheter is positioned near the tip of the cannula after insertion within the human body. In the preferred embodiment, the stylet may be releasably locked in position within the cannula. The disclosed design allows the user to sample fluid through the tip of the inserted cannula and to inject medication into the insertion site without having to re-introduce a needle therein.

Abstract: An implantable valve for allowing 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 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 a pressure differential applied thereto, regulates passage of CSF from the ventricular spaces to the drainage location. When differential pressure is relatively small, the valve is actuated to a constant pressure mode in which a predetermined differential pressure across the valve is maintained. In response to a sudden increase in differentail pressure, the valve mechanism is actuated to a constant flow mode in which a desired relatively constant rate of fluid flow is maintained.

Abstract: An implantable valve for allowing 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 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 is relatively small, the valve operates in a constant pressure mode to maintain a predetermined pressure differential across the valve. In response to a sudden increase in differential pressure, the valve mechanism operates in a constant flow mode to maintain a desired relatively constant CSF flow rate through the valve.