Abstract: A snare-type device for removing an elongated structure such as, for example, a pacemaker lead. The device first includes a sheath having a first lumen formed therein, the first lumen having a distal end and being dimensioned to receive the elongated structure therein, and being adapted to allow advancement of the sheath along the elongated structure. The sheath also has second and third parallel lumens formed therein, all of the first, second and third lumens being unitarily formed in the sheath. The device also includes a snare contained in the second and third lumens in the sheath. The snare has a snare loop extending out of the second and third lumens, at and generally extending around the distal end of the first lumen.

Abstract: A snare-type device (10) for removing an elongated structure (54) such as, for example, a pacemaker lead. The device (10) first includes a sheath (12) having a first lumen (16) formed therein, the first lumen (16) having a distal end (24) and being dimensioned to receive the elongated structure (54) therein, and being adapted to allow advancement of the sheath (12) along the elongated structure (54). The sheath (12) also has second and third parallel lumens (28 and 36) formed therein, all of the first, second and third lumens (16, 28 and 36) being unitarily formed in the sheath (12). The device (10) also includes a snare (42) contained in the second and third lumens (28 and 36) in the sheath (12). The snare (42) has a snare loop (44 or 52) extending out of the second and third lumens (28 and 36), at and generally extending around the distal end (24) of the first lumen (16).

Abstract: Disclosed is a heart lead removal apparatus for removing an range of different sized implanted cardiac pacemaker or defibrillator leads from the heart, typically through a blood vessel leading to the heart. The lead removal apparatus comprises a stylet, an expandable portion, and an actuator portion which is manually advanced by the operator to cause the expandable portion to engage the coils within a pacemaker coil lumen. In one preferred embodiment, the expandable portion comprises a multifilar wire bundle that is helically wound around the stylet and attached about the tip thereof. The actuator portion, which comprises an elongate metal cannula attached to a first handle, is urged forward to contact the proximal end of the expandable portion, thereby causing the individual wires of the multifilar wire bundle to deform outward in a random fashion.

Abstract: Disclosed is a heart lead removal apparatus for removing an range of different sized implanted cardiac pacemaker or defibrillator leads from the heart, typically through a blood vessel leading to the heart. The lead removal apparatus comprises a stylet, an expandable portion, and an actuator portion which is manually advanced by the operator to cause the expandable portion to engage the coils within a pacemaker coil lumen. In one preferred embodiment, the expandable portion comprises a multifilar wire bundle that is helically wound around the stylet and attached about the tip thereof. The actuator portion, which comprises an elongate metal cannula attached to a first handle, is urged forward to contact the proximal end of the expandable portion, thereby causing the individual wires of the multifilar wire bundle to deform outward in a random fashion.

Abstract: A noninvasive, perforate, self-centering locator (10) facilitates engagement of a needle or cannula with a vascular access device (44) of the type having a subcutaneously implanted infusion port (46) and an infusion chamber (48) contained in the infusion port (46), the infusion chamber (48) being covered by a septum (52). The locator (10) is exemplified by a port stabilizer ring (12) having a central opening (18) with an interior diameter greater than the diameter of the septum (52) but less than the greatest diameter of the infusion port (46). The stabilizer ring (12) or other embodiment of the locator (10) is pressed on the skin (45) over the site of the infusion port (46), and simultaneously visually locates the septum (52) for the user while stabilizing the infusion port (46) with respect to the skin (45) and underlying tissues, permitting ready penetration of the skin (45) and septum (52) by a needle or cannula (58).

Abstract: A locally flexible dilator sheath (10) for separating encapsulating tissue from an implanted cardiac electrical lead. The dilator sheath includes an elongated tubular member (11) of a rigid stainless steel material, which is sized for placement of the tubular member over a cardiac lead that is implanted in the vascular system of a patient. The distal end (13) of the rigid tubular member is beveled to ease the separation of extremely tough tissue that encapsulates an implanted cardiac lead. To ease insertion around curves in the vascular system of the patient, the elongated tubular member includes a relieved portion (14). The relieved portion includes a relief pattern (15) of apertures (16,17,19,23) in the elongated tubular member. The relief apertures preferably include diametrically opposed slots (24,25) that extend perpendicularly into the tubular member. Adjacent pairs (44,45) of slots are circumferentially offset a 90.degree. angle (26) to add further lateral flexibility to the relieved portion.

Abstract: A closed-end catheter having a flat-surfaced valve positioned in a recess about the distal portion of the catheter for preventing retrograde flow of blood therethrough when positioned in a blood vessel of a patient. The valve catheter comprises a flexible material, cylindrical tube having a semi-circular cross-sectional wall extending longitudinally about the distal portion thereof. The laterally facing valve is formed in a planar surface of a flexible material layer attached to the wall in the distal portion of the cylindrical tube. One or more passages extend through the cylindrical tube in which medicaments or fluids can be simultaneously injected or aspirated. The valve is formed by inserting one or more flat-surfaced rods in the passages of the tube to stretch the surrounding wall. A flat-surfaced layer of flexible material is applied over the flat-surfaced rod to the stretched wall.

Abstract: A closed-end catheter having a flat-surfaced valve positioned in a recess about the distal portion of the catheter for preventing retrograde flow of blood therethrough when positioned in a blood vessel of a patient. The valve catheter comprises a flexible material, cylindrical tube having a U-shaped outer wall extending longitudinally about the distal portion thereof. A flat-surfaced valve is positioned in the recess along the U-shaped distal portion and attached to the outer wall. The valve is formed by inserting a flat-surfaced rod in the U-shaped portion of the tube to stretch the outer wall. A flat-surfaced layer of flexible material is applied over the flat-surfaced rod to the stretched outer wall. The flexible material layer is cured and a longitudinal fluid aperture formed therein with the rod remaining in the passage of the U-shaped portion. The rod is then removed and a plug inserted into the passage to close the distal end of the catheter.

Abstract: A fuel bundle in which the fuel rods are supported by top and bottom plates and held together by axially spaced straps. Several of the fuel rods are formed as tie rods. Each tie rod has a flat key at the bottom which is passed through a slot in the bottom plate. By turning the tie rod, the key is rotated to a locking position in which its axial movement is prevented. At the top, each tie rod has a flattened plug which is threaded on its rounded sides to receive a nut that has a crimping lip. The plug extends through a slot in the top plate and is threaded to the nut and the crimping lip is crimped to the plug. The tip of the plug is flat. During reconstitution of the fuel bundle, the crimp on each tie rod is broken and the nut is unscrewed while the tip of the plug is held. The top plate is then removed and each tie rod is then turned so that the key can be passed through the slot in the bottom plate. The tie rods may thus be removed and the bundle disassembled without access to the bottom plate.

Abstract: A device for relieving thermally induced stresses developed in a nuclear fuel assembly during reactor heatup is disclosed herein. The device generally comprises a stress relieving fastener capable of connecting a fuel assembly top nozzle, which may be stainless steel, to a threaded stud, which may be Zircaloy. The stud is attached to a fuel assembly channel. The fastener includes a threaded nut having a deformable portion for relieving thermally induced stresses developed in the stud by the differential thermal expansion of the top nozzle and stud. In a first embodiment of the nut, the deformable portion comprises a circumferential, deformable ridge which is substantially recessed from the marginal edge of the nut and which is disposed on the bottom most surface of the nut. The ridge contacts the top nozzle when the nut threadedly engages the stud. A second embodiment of the nut is similar to the first embodiment except that the deformable ridge is disposed flush with the marginal edge of the nut.

Abstract: A fuel assembly has a plurality of elongated fuel rods, a plurality of grid structures axially spaced from one another along the fuel rods between opposite ends thereof and supporting the fuel rods in a side-by-side spaced array, and a pair of tie plates disposed at the respective opposite ends of the fuel rods. Each of the fuel rods has a pair of end plugs sealing opposite ends thereof, with at least the end plug at one of the opposite ends of each fuel rod having an extension member thereon which extends axially outward from the end plug and is of a diameter less than that of the fuel rod. At least one of the tie plates has a plurality of holes defined by endless sidewalls formed therethrough between opposite sides of the tie plate and in an array which matches that of the fuel rods.

Abstract: A hollow water cross disposed in an outer flow channel of a fuel assembly so as to divide an array of fuel rods in the assembly into a plurality of subgroups is composed of a plurality of hollow panels which extend radially from a central axis of the water cross and define an open inner flow channel. The panels are interconnected at their outer ends with angularly displaced portions of the outer channel and at their inner ends with one another so as to define a central channel portion which extends the axial length of the water cross. The improvement relates to a cross brace disposed within the central channel portion of the water cross generally along the central axis thereof. The cross brace includes radially-extending portions which extend within and parallel to the respective water cross panels and interconnect with dimples formed in each panel so as to reinforce and stiffen the water cross and thereby the outer channel of the fuel assembly.