Abstract:
Devices and methods for placing medical leads using minimally invasive techniques. One lead includes a lead body connected to a lead head having an aperture for providing fiber optic access to the interior of a helical electrode. The fiber optic shaft may be disposed within or along-side a drive shaft releasably coupled to the head to rotate the head. The drive shaft and lead body may be delivered using a delivery catheter. The delivery catheter can be advanced though a small incision to the target tissue site, and the site remotely visualized through the fiber optic scope extending through the lead head aperture. Some catheters include a distal mapping electrode readable from the catheter proximal portion or handle. The lead head can be rotated, rotating the helical electrode into the tissue, and the catheter, drive shaft, and fiber optic probe removed. In one use, epicardial pacing leads are placed on the posterior surface of the heart, aided by visualization and mapping to obtain optimal electrode placement and patient outcome.
Abstract:
A bandstop filter having optimum component values is provided for a lead of an active implantable medical device (AIMD). The bandstop filter includes a capacitor in parallel with an inductor. The parallel capacitor and inductor are placed in series with the implantable lead of the AIMD, wherein values of capacitance and inductance are selected such that the bandstop filter is resonant at a selected frequency. The Q of the inductor may be relatively maximized and the Q of the capacitor may be relatively minimized to reduce the overall Q of the bandstop filter to attenuate current flow through the implantable lead along a range of selected frequencies.
Abstract:
Implantable electrical lead wires, such as cobalt-chromium-molybdenum alloy wires, are coated with a metal, ceramic, or carbon to a thickness of about 100 nm or less to provide a non-reactive interface to polyurethane sheathing materials. Preferred is sputter coating an amorphous carbon intermediate the alloy wire and the polyurethane sheath.
Abstract:
A feedthrough terminal assembly for an active implantable medical device (AIMD) includes a plurality of leadwires extending from electronic circuitry of the AIMD, and a lossy ferrite inductor through which the leadwires extend in non-conductive relation for increasing the impedance of the leadwires at selected RF frequencies and reducing magnetic flux core saturation of the lossy ferrite inductor through phase cancellation of signals carried by the leadwires. A process is also provided for filtering electromagnetic interference (EMI) in an implanted leadwire extending from an AIMD into body fluids or tissue, wherein the leadwire is subjected to occasional high-power electromagnetic fields such as those produced by medical diagnostic equipment including magnetic resonance imaging.
Abstract:
An energy management system facilitates the transfer of high frequency energy coupled into an implanted lead at a selected RF frequency or frequency band, to an energy dissipating surface. This is accomplished by conductively coupling the implanted lead to the energy dissipating surface through an energy diversion circuit including one or more passive electronic network components whose impedance characteristics are at least partially tuned to the implanted lead's impedance characteristics.
Abstract:
A discoidal feedthrough capacitor has its active electrode plates disposed within a dielectric body so that an edge of the active electrode plates is exposed at a surface of a through-hole for a conductive lead. The conductive lead is conductively coupled to the exposed edge of the electrode plates without an intervening conductive termination surface. Similarly, a ground electrode plate set of the feedthrough capacitor may have an edge exposed at the outer periphery of the capacitor for conductively coupling the exposed edge of the ground electrode plate to a conductive ferrule without an intervening conductive termination surface.
Abstract:
Devices and methods for stimulating nerves, such as peripheral nerves are described. Some devices can include small cross-section lead bodies having one or more electrodes in the round distal portion, the electrodes having a substantially planar surface within the distal portion of the lead which is suitable for placement through a cylindrical needle intended to access a spinal region of a patient. Some lead electrodes are covered with a hydrophilic coating at least about 0.001 inches thick. The hydrophilic coating may include a steroid and/or a GABA (gamma-aminobutyric acid) agonist which can elute or diffuse over time, away from the electrode.
Abstract:
Metal vanadium oxide particles have been produced with an average diameter less than about 500 nm. The particles are produced from nanocrystalline vanadium oxide particles. Silver vanadium oxide particles, for example, can be formed by the heat treatment of a mixture of nanoscale vanadium oxide and a silver compound. Other metal vanadium oxide particles can be produced by similar processes. The metal vanadium oxide particles have very uniform properties.
Abstract:
The present invention is directed to any electrochemical cell casing design having an electrolyte fill aperture. The electrolyte fill aperture receives and directs the electrolyte into the casing. A fill plug has at least two components—an insert section detachably connected to a placement unit. The placement unit allows a user to properly position the insert section into the electrolyte fill aperture. Once this is done, the placement unit is detached from the insert section. The insert section in then hermetically sealed to the casing. If desired, the fill plug can be used for filling the electrolyte in the casing.
Abstract:
Active implantable medical devices (AIMDs) are backfilled with a dielectric fluid to increase the volts per mil dielectric breakdown strength between internal circuit elements. In a method for backfilling the AIMD with dielectric fluid, substantially all air and moisture is evacuated from the AIMD housing prior to backfilling the AIMD housing with a dielectric fluid having a dielectric breakdown strength greater than air, nitrogen or helium. The AIMD is constructed to accommodate volumetric expansion or contraction of the dielectric fluid due to changes of pressure or temperature of the dielectric fluid to maintain integrity of the AIMD.