Abstract: A modular hydraulic spinal intervertebral prosthetic device offering individualized optimization of an implantable disc prosthesis by having selectable crown plates modules with differing lordosis angles and differing cross-sectional profiles, and selectable bellows cartridges having differing load-bearing capabilities. The device offers substantially full physiological degrees of motion, and by the incorporation of both a dashpot mechanism and a biasing element within reversibly displaceable and tiltable bellows provides hydraulic load bearing capability. The bellows assembly is advantageously pre-loaded to sub-atmospheric pressure. The dashpot further increases resistance to lateral sheer loading beyond the bellows convolutions acting alone. Rotational coupling of the upper crown plate and center bearings plate permits normal twisting movements, and spinal flexural freedom is provided by the bellows interposed between the center bearings plate and the lower crown plate.

Abstract: A pressure sensor for indicating pressure in the animal or human body, such as intracranial pressure, including a housing, a bellows contained within the housing, a body pressure sensing tambour for placing the bellows in communication with pressure in the body so that the pressure will cause the bellows to move as a function of the pressure, output means, such as a radioactive source and associated shielding, contained within the housing and associated with the bellows for providing an output which is a function of the movement of the bellows, and a receiver, such as a radiation detector, located external to the body to receive the output and provide data indicative of the pressure in the body. The pressure sensor includes means associated with the bellows to enable in vivo calibration of the pressure sensor after implantation by establishing a preselected output condition during calibration. An ambient pressure sensing tambour is associated with the bellows for compensating for ambient pressure variations.

Abstract: A non-invasive nuclear device for communicating pressure inside a body to the exterior, such as from within the cranium, bladder or vena cava, of an animal or human, the device including a housing having an interior communicating through a conduit of deformable metallic material with a fluid pressure sensing device positioned within the body portion being monitored, the housing being mounted on the body adjacent the body portion being monitored, a shaped mass of radioactive material together with radiation shield means being disposed within the housing interior together with urging means for producing a predetermined shielding relationship between the radioactive mass and the shield means, the radioactive mass being supported on the urging means for guide movement relative to the shield means and the sensed pressure being exerted through a pressure transmitting fluid flowing within the deformable metal conduit against the urging means for modifying the shielding relationship between the radioactive mass and t

Abstract: A pressure sensor apparatus primarily for sensing pressure in a body cavity such as the cranium, bladder or vena cava of an animal or human comprising a housing having non-radioactive fluids contained in two spaced apart regions of the housing. A radioactive fluid immiscible with at least one of the non-radioactive fluids is also contained within the housing between the non-radioactive fluids. The interface between the radioactive fluid and one of the non-radioactive fluids is optionally formed by a resilient member such as an elastomeric diaphragm. A flexible member is connected to the housing and communicates with one of the two spaced apart regions in the housing. The other spaced apart region in the housing is closed by a resilient member such as a metallic diaphragm. With this arrangement, the movement of the radioactive fluid is proportional to the pressure sensed by the flexible member and is sensed by a radiation detector.

Abstract: A pressure sensor apparatus primarily for sensing pressure in a body cavity such as the cranium, bladder or vena cava of an animal or human comprising a Bourdon or bellows type pressure gauge connected to a flexible member such as a metallic disc or corrugated bellows tambour containing a non-radioactive fluid. A discrete mass of radioactive material is connected to the pressure gauge and moves proportionally to the pressure sensed by the flexible member. A radiation detector senses the movement of the radioactive material through a window in a radiation shield.