Surgery – Diagnostic testing – Flexible catheter guide
Reexamination Certificate
2000-04-26
2002-04-16
Hindenburg, Max (Department: 3736)
Surgery
Diagnostic testing
Flexible catheter guide
C427S002300
Reexamination Certificate
active
06371929
ABSTRACT:
BACKGROUND
The present invention relates to steerable coated guidewires for introduction into vessels such as blood vessels to aid in placement of devices such as catheters into the vessels. Particularly, the invention relates to a process or method, and apparatus for making coated steerable guidewires having a substantially constant outer diameter and being of contiguous construction from the proximal end to the steerable and flexible distal end. Additionally the invention relates to the steerable coated guidewires produced by the method and apparatus of the invention.
FIELD OF THE INVENTION AND PRIOR ART
Steerable guidewires which are known to the inventor hereof, required either elaborate capping procedures and apparatus for a tapered end of the wire to achieve a very flexible, but constant diameter wire, or they required the use of one or more shape memory alloy wires alone or in combination, annealed to provide steering upon heating of the wires.
An example of a known steerable guide wire for use in medical procedures which requires an elaborate capping procedure comprises a core wire of preferably stainless steel which runs the entire length of the guide wire. The distal end of the core tapers twice to an intermediate and final diameter. The distal tip of the core wire may be flattened to enhance handling and flexibility. A flat wire coil may be in contact with the first taper and is brazed at each end to the core wire. A flexible coil spring is attached to about the most distal 5 cm of the core wire. The spring is tightly wound at its proximal end and more loosely wound at its (and the core wire's) distal end to improve flexibility at the distal tip of the guide wire. At the distal end, the coil spring and the core wire are coextensive and fixedly attached together by a hemispherical weld at the distal tip of the guide wire.
In the manufacture of known steerable guidewires, it has been necessary to manually affix a soft tip on the tapered distal end of the wire. Affixing the tip manually is very labor intensive, very costly and, because the tip is a separate part from the coating on the shaft, a degree of risk exists that the tip could fall off in use, i.e., while inside a vessel of the body.
It would be desirable to have a steerable guidewire the steering or directing of which does not require the use of heat to deform shape memory alloys. It would also be very desirable to have a steerable guide wire which does not require the distal end to be specially designed with springs or other devices and procedures to create a distal end that has a constant diameter but which is very flexible to the extent that it will conform to the direction of the vessel into which it is being inserted.
It would be desirable if a steerable guide wire could be made without excessive processes and procedures involved in the extrusion process of making the constant diameter steerable guidewire thereby potentially improving the constancy of the steerable nature of the guidewire and improving the reliability of the performance of the guidewire.
The following patents show the state of the art in the field of steerable guidewires.
The U.S. Pat. No. 5,211,183 patent to Wilson, (the '183 patent) discloses a steerable memory alloy guide wire for use in positioning medical devices inside the body. The guide wire may be formed of any shape memory alloy or other transitional temperature activated mechanical memory materials. The guide wire is comprised in whole or in part of one or more heat activated memory alloys alone or in combination with one or more non-heat activated materials. The alloy is annealed to particular shapes (for example curves) then cooled and formed into its previously annealed shape. The invention applies the shape memory alloy concept to provide accurate steering capability to guide wires in various forms. Heating of the wire may be by induction, application of RF energy, immersion heating by water, or body temperature. If electrical current is used, the guide wire and any electrical wires may be insulated by a non-conductive sleeve or coating. The shape memory alloy may comprise all or part of a guide wire or multiple wires of memory alloy, annealed to different shapes or curves, may be bound together and used, having been annealed, for example, to work equally in opposite directions, to provide additional steering capability.
The U.S. Pat. No. 5,069,217 patent to Fleischhacker Jr. (the '217 patent) discloses a steerable guide wire for use in medical procedures. The wire is comprised of a core wire of preferably stainless steel which runs the entire length of the guide wire. The distal end of the core tapers twice to an intermediate and final diameter. The distal tip of the core wire may be flattened to enhance handling and flexibility. A flat wire coil may be in contact with the first taper and is brazed at each end to the core wire. A flexible coil spring attached to about the most distal 5 cm of the core wire. The spring is tightly wound at its proximal end and more loosely wound at its (and the core wire's) distal end to improve flexibility at the distal tip of the guide wire. At the distal end, the coil spring and the core wire are coextensive and fixedly attached together by a hemispherical weld at the distal tip of the guide wire. The hemispherical tip provides for smooth insertion and maneuvering of the wire. The main body of the core wire, proximal to the first taper may be coated with a polymer to improve handling characteristics. However, the most proximal end of the guide wire and the distal end with the coiled spring may be left uncoated—there then results in some small net taper of the outer diameter of the guide wire as a whole from the coated portion to the uncoated tip.
The U.S. Pat. No. 5,025,799 patent to Wilson (the '799 patent), a division of the above-mentioned Wilson U.S. Pat. No. 5,211,183 patent, the difference being the claims. The claims of this patent are directed to the guide wire being comprised of at least one solid elongated strand constructed of shape memory alloy material wherein at least one portion along the length of the strand is annealed to affect a shape change upon application of heat. The claims of the above '183 patent are directed to a guide wire comprising at least a pair of solid elongated shape memory wire members held in substantial coaxial engagement with each other but so as to allow relative sliding movement between the two, wherein one of the wire members is annealed to under go a shape change in one direction and another is annealed to undergo a shape change in another direction, the guidewire as a whole being rotatable to enable omnidirectional steering of the guide wire.
The U.S. Pat. No. 5,800,890 patent to Cramer (the '890 patent) discloses a steerable guide wire for catheters, which may be a combination catheter and guide wire. The guide wire is composed of a hollow metal guide tube through which liquid may flow. The guide tube is made of a plurality of tapering metal tube sections, each section tapering from proximal to distal end and each succeeding proximal end insertable into the preceding distal end and soldered together to form one tapering guide tube. Attached to the distal end of the tube is a helically wound spring, overlapping (for stability) a substantial part of the distal end of the guide tube but extending beyond the distal end of the guide tube. The distal end of the spring has a rounded cap. There is also a fine wire attached at the cap end of the spring and running to the proximal end of the spring where it is also attached to the spring. The wire provides stability and prevents the spring form being over-extended and causing damage to the vessel into which it is inserted. There may also be included a turning handle at the proximal end of the guide tube for steering and placement of the tube. There are then disclosed several applications of use of the steerable guide wire/guide tube including applications in which there is a connector, at the proximal end of the guide tu
Dishong George W.
Hindenburg Max
Wingood Pamela
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