Abstract: A tool for inserting medical electrodes such as nerve-stimulating electrodes into tissue. An electrode is positioned fully within a tip of the tool so the tip end can be placed directly against the tissue to be penetrated for precise handheld positioning. A trigger on the tool is actuated to release a compressed spring in the tool to drive the electrode out of the tool tip into the target tissue. A viscous-damping means is provided in the tool to control electrode acceleration and velocity.

Abstract: A tool for inserting medical electrodes such as nerve-stimulating electrodes into tissue. An electrode is positioned fully within a tip of the tool so the tip end can be placed directly against the tissue to be penetrated for precise handheld positioning. A trigger on the tool is actuated to release a compressed spring in the tool to drive the electrode out of the tool tip into the target tissue. A viscous-damping means is provided in the tool to control electrode acceleration and velocity.

Abstract: Iridium electrodes of very small diameter such as 35 microns are formed from larger-diameter commercially available iridium wire by an electrolytic etching process. A saturated solution of sodium chloride in a preferred etching solution. The electrodes are formed with sharp conical tips which can be rounded or blunted if desired by additional etching. Platinum lead wire is welded to the electrode shank, and the electrode is coated with an insulating varnish which is ablated at the electrode tip to expose a conductive surface.

Abstract: The invention is a method of attracting lymphocytes to at least one desired location in the body of a patient for a therapeutic purpose (e.g., treating infection or inflammation, killing tumor cells, etc.), the method comprising contacting the desired location with one or more electrodes and stimulating the tissue with current at an intesity below that which will physically damage the cells, yet sufficient to attract lymphocytes.

Abstract: A surgical tool for controlling the depth of penetration of a cutter into bone. The tool has a tubular housing with three legs extending therefrom to provide a tripod-like support when positioned against the bone surface. A penetration-depth adjustment ring or sleeve is rotatable on the tubular housing, preferably in click-stop detented intervals, to establish a desired penetration depth for the cutter.

Abstract: A circumneural electrode assembly having a pair of spaced-apart and oppositely directed helical portions which can be opened by an insertion tool to fit the assembly over a peripheral or cranial nerve. One or more conductive electrodes on the inner surfaces of the helical portions intimately contact the nerve surface to deliver electrical stimulating signals, or alternatively, to block nerve conduction or to sense evoked potentials. The surgically implanted assembly is stable in position on the nerve, and is installed with a minimum of nerve manipulation and possible resulting trauma. The assembly preserves the advantages of previously disclosed spiral electrodes, while greatly simplifying installation, particularly in a nerve which is deeply recessed in overlying muscle or arteries.

Abstract: A nerve-stimulating electrode assembly for installation within or adjacent the lower end of the dura mater to enable regaining of at least partial control over lower-body functions directed by nerves emerging from the end of the spinal cord. In one form, the electrode assembly has an internal passage enabling injection of fluids, whereby electrical stimulation, chemical treatment, or both forms of therapy may be used either intra- or extradurally.

Abstract: An implantable helical electrode assembly configured to fit around a nerve for electrically triggering or measuring an action potential or for blocking conduction in nerve tissue. A multiconductor flexible cable connects the electrode to an implanted signal receiver, and the assembly may include multiple individual flexible ribbon electrodes each partially embedded in a portion of the peripheral surface of a helically formed dielectric support matrix. The spiral configuration of the assembly is easy to install around a nerve bundle during surgical implantation, and the resiliency of the assembly minimizes the risk of damage to nerve tissue. The tissue-contacting surface of each electrode is roughened to increase the electrode surface area.

Abstract: A wireless, surgically implantable pressure transducer for measuring pressure of fluid or tissue in a body chamber such as a brain ventricle of a patient suffering hydrocephalus or a head injury. The transducer includes an inductor and a capacitor connected in parallel to form a resonant L-C circuit. One of these reactive components is variable, and a bellows (or similar pressure-sensitive force-summing device) is mechanically connected to the variable component to vary the value of capacitance or inductance and hence the resonant frequency of the L-C circuit in response to pressure changes of the fluid in which the bellows is immersed. The transducer is electromagnetically coupled to an external source of variable-frequency energy such as a grid-dip oscillator, enabling external detection of the transducer resonant frequency which is a measure of the fluid pressure being sensed.

Abstract: A wireless, surgically implantable pressure transducer for measuring pressure of fluid or tissue in a body chamber such as brain ventricle of a patient suffering hydrocephalus or a severe head injury. The transducer includes a coaxial variable capacitor electrically connected across an inductor to form a parallel resonant L-C circuit. Alternatively, a coaxially variable inductor may be connected across a capacitor to form the L-C circuit. A bellows is mechanically connected to the variable component to vary the value of capacitance or inductance and hence the resonant frequency of the L-C circuit in response to pressure changes of the fluid in which the bellows is immersed. The transducer is electromagnetically coupled to an external source of variable-frequency oscillatory energy such as a grid-dip oscillator which enables external detection of the transducer resonant frequency which is in turn indicative of the level of fluid pressure being sensed.