Patent Description:
Catheter-deflection technology and improvements thereto, such as ergonomic improvements, remain an ongoing concern in the medical arts.

<CIT> describes an irrigated tip catheter having one or more puller wires attached at their distal ends to the tip section and at the their proximal ends to the control handle for deflecting the tip section by manipulation of the control handle. <CIT> describes an MR compatible steerable sheath including a steerable shaft that receives first and second longitudinal movement wires at a distal end thereof and audible or tactile means for indicating to a user the degree of deflection of the distal tip of the steerable shaft. A control handle is coupled to a proximal end of the first and second longitudinal movement wires and causes longitudinal movement of the wires.

A catheter that includes a mechanism for deflecting a distal portion of a catheter is disclosed. The catheter comprises a deflection knob including a first thread, a rod including a second thread that is coupled to the first thread, and a puller wire that is connected to the rod. The rod comprises a proximal portion upon which the second thread is disposed and a distal portion to which the puller wire is connected. As such, the second thread may be disposed on an outer surface of the rod. In various embodiments, the first thread may comprise a female thread and the second thread may comprise a male thread. In alternative embodiments, the first thread may comprise a male thread and the second thread may comprise a female thread.

The distal portion of the rod includes a pocket to which the puller wire may be connected. Specifically, a joining feature is secured in the pocket and attached to a proximal end of the puller wire. The joining feature comprises a first ferrule joined, e.g., crimped, to the proximal end of the puller wire. The joining feature also comprises a second ferrule secured, e.g., bonded, in the pocket and attached, e.g., crimped, to the first ferrule. In preferred embodiments, the first ferrule comprises stainless steel and the second ferrule comprises brass.

The deflection knob preferably includes a longitudinal bore having a surface such that the first thread may be disposed on the surface and such that the proximal portion of the rod may be disposed through the longitudinal bore. The deflection knob and rod may be incorporated as components of a subassembly into a handle of the catheter. The subassembly may additionally include a stationary component, e.g., a collar. A catheter body of the catheter may be connected at a proximal end to the stationary component and connected at a deflectable distal end to a distal end of the puller wire. Additionally, the rod may define therethrough an internal passageway such that additional structures of the catheter (e.g., irrigation tubing, lead wires) may extend through the internal passageway.

The catheter may thus be used according to methods and variations where the distal end of a catheter body of the catheter may be deflected. Such methods may include rotating the deflection knob, translating the rod, and displacing the puller wire. The step of rotating the deflection knob may cause the steps of translating the rod and displacing the puller wire to occur.

While the specification concludes with claims, which particularly point out and distinctly claim the subject matter described herein, it is believed the subject matter will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:.

<FIG> shows a catheter <NUM> including an elongated catheter body <NUM> having proximal and distal ends, <NUM> and <NUM>, respectively. A control handle <NUM> including a control knob <NUM> may be disposed at the proximal end of the catheter body. As seen in <FIG>, catheter body <NUM> comprises an elongated tubular construction having an axial or central lumen <NUM>. Catheter body <NUM> is flexible, i.e., deflectable, but substantially non compressible along its length. Catheter body <NUM> can be of any suitable construction and made of any suitable material. A presently preferred construction comprises an outer wall <NUM> made of polyurethane or PEBAX®. The outer wall <NUM> may comprise an embedded braided mesh of stainless steel or the like to increase torsional stiffness of catheter body <NUM>.

As shown in <FIG>, a puller wire <NUM> may be disposed in lumen <NUM> of catheter body <NUM>. Puller wire <NUM> is provided for deflection of a portion of the catheter, e.g., the distal end of catheter body <NUM>. As such, the puller wire <NUM> extends through the catheter body <NUM> whereupon it may be attached to the distal end of the catheter in lumen <NUM>. A proximal end of puller wire <NUM> may be anchored to the control handle <NUM>, particularly to a component that may be manipulated via movements of knob <NUM> as explained below. Puller wire <NUM> may be fabricated from any suitable metal, such as stainless steel, cobalt chromium, beryllium copper, or Nitinol. Further, it may be coated with a low-friction material, e.g., TEFLON® to impart lubricity to puller wire <NUM>. Puller wire <NUM> may have a diameter ranging from, e.g., about <NUM> to <NUM> (<NUM> to about <NUM> inch).

Longitudinal movement of the puller wire <NUM> relative to the catheter body <NUM>, results in deflection of the distal end of catheter body <NUM>. Such movement may be accomplished by suitable manipulation of the control handle <NUM>, as described in, e.g., <CIT> and <CIT>. Another mechanism for imparting longitudinal movement to puller wire <NUM> is described with reference to <FIG>.

<FIG> shows a subassembly <NUM> of a handle mechanism for use with a deflectable catheter. Subassembly <NUM> includes a control knob <NUM>, a rod <NUM>, and a stationary component, e.g., collar <NUM>. As shown, knob <NUM>, rod <NUM>, and collar <NUM> each have a cylindrical form and are arranged concentrically with each other about longitudinal axis <NUM> of subassembly <NUM>. Such concentricity is not required, however, to practice the disclosed subject matter. Rod <NUM> may be coupled to control knob <NUM> such that rotation of knob <NUM> about axis <NUM> causes linear motion, i.e., translation of rod <NUM> relative to knob <NUM> along or parallel to axis <NUM>. Collar <NUM> may be maintained in a stationary state relative to knob <NUM> and rod <NUM>, such that it may be configured to restrict rotational motion of rod <NUM> about axis <NUM>. As such, rod <NUM> can be pulled into collar <NUM> by rotating knob <NUM> one way (e.g., clockwise) and pushed out of collar <NUM> by rotating knob <NUM> the other way (e.g., counterclockwise).

Threads may be used to impart linear motion to rod <NUM> via application of rotational forces to knob <NUM>. Such a mechanism also prevents linear forces applied to rod <NUM> from causing knob <NUM> to rotate. As seen in <FIG>, which is an exploded view of subassembly <NUM> with some components removed for clarity, female threads <NUM> may be disposed on an outer surface <NUM> of rod <NUM> at proximal end <NUM>. With further reference to <FIG>, male threads <NUM> may be disposed on an internal surface of knob <NUM>. For example, knob <NUM> may define a bore therethrough and the male threads may be disposed about the circumference of the bore. The coupling of knob <NUM> and rod <NUM> via their respective threads allow for linear motion of rod <NUM> to be caused by rotation of knob <NUM>. Of course, the same cause and effect may be realized by providing rod <NUM> with male threads and knob <NUM> with female threads.

Rod <NUM> is connected to a puller wire <NUM>, best seen in <FIG>, which is a detail view of the distal end <NUM> of rod <NUM>. The connection is realized via a joining feature <NUM> connected to distal end <NUM>. Preferably, joining feature <NUM> may include between one and three ferrules, e.g., two ferrules. As seen in <FIG>, a first ferrule <NUM> is be attached, e.g., crimped, onto puller wire <NUM>, and a second ferrule <NUM> is attached, e.g., crimped, onto first ferrule <NUM>. Second ferrule <NUM> is coupled to distal end <NUM> of rod <NUM> by attaching it thereto via a pocket <NUM> formed in distal end <NUM>. For example, second ferrule <NUM> may be bonded or glued in pocket <NUM>. In preferred embodiments, first ferrule <NUM> may be fabricated from stainless steel and second ferrule <NUM> may be fabricated from brass. Joining feature <NUM> provides a robust joint between rod <NUM> and puller wire <NUM> because the surface area of second ferrule <NUM> in pocket <NUM> is substantially greater than the surface area of a proximal portion of wire <NUM> that might otherwise be directly attached therein. As such, friction forces and other bonding forces between pocket <NUM> and second ferrule <NUM> are greater than they would otherwise be if a distal portion of wire <NUM> were directly attached to rod <NUM> without ferrule <NUM>. First ferrule <NUM> also contributes to the robustness of the joint. As shown, first ferrule <NUM> has a cylindrical form, which allows it to be crimped onto the proximal end of wire <NUM> without pinching it, damaging it, or otherwise causing a stress concentration that could lower the maximum tensile load or number of cycles that wire <NUM> would otherwise be able to handle until failure.

Because puller wire <NUM> is connected to rod <NUM> via joining feature <NUM>, linear motion of rod <NUM> effected by rotation of knob <NUM> causes a corresponding linear motion or displacement of puller wire <NUM>. By connecting puller wire <NUM> to another object, that object may be manipulated by movements of puller wire <NUM> caused by rotations of knob <NUM>.

A catheter body of a catheter, such as catheter body <NUM> of catheter <NUM>, may be connected at its proximal end to handle subassembly <NUM>, e.g., directly or indirectly to the stationary component, e.g., collar <NUM>. Preferably, distal end <NUM> of catheter body <NUM> has an internal diameter slightly smaller to slightly larger than the outer diameter of collar <NUM> to permit attachment via, e.g., an interference fit, bonding with an adhesive, or both. Because rod <NUM> may be advanced or retracted through collar <NUM>, the outer diameter of rod <NUM> is smaller than the inner diameter of collar <NUM>, indicating that the outer diameter of rod <NUM> is also smaller than the inner diameter of catheter body <NUM>. As such, puller wire <NUM> may extend through catheter body <NUM>, from its proximal end <NUM> to its distal end <NUM>. Puller wire <NUM> may further be anchored at the distal end <NUM> of catheter body <NUM>, e.g., via a glue joint. Accordingly, translating puller wire <NUM> proximally causes distal end <NUM> of catheter body <NUM> to deflect, e.g., toward the dotted line shape shown in <FIG>. Subsequent distal translation of puller wire <NUM> causes distal end <NUM> of catheter <NUM> to return toward its original shape.

Rod <NUM> additionally defines an internal passageway <NUM> therethrough. Additional catheter structures that pass through handle subassembly <NUM> may pass through passageway <NUM>. For example, a lead wires <NUM> and an irrigation tube <NUM> may be disposed through passageway <NUM>.

By virtue of the embodiments illustrated and described herein, Applicant has devised a method and variations thereof for using a catheter, such as catheter <NUM> including subassembly <NUM>, the method including steps of rotating a deflection knob (e.g., knob <NUM>), translating a rod (e.g., rod <NUM>), and displacing a puller wire (e.g., <NUM>). In preferred variations, the step of rotating the deflection knob causes the steps of translating the rod and displacing the puller wire to occur, which causes the distal end of the catheter body to deflect.

Any of the examples or embodiments described herein may include various other features in addition to or in lieu of those described above. The teachings, expressions, embodiments, examples, etc., described herein should not be viewed in isolation relative to each other. Various suitable ways in which the teachings herein may be combined should be clear to those skilled in the art in view of the teachings herein.

Claim 1:
A catheter, comprising:
a deflection knob (<NUM>) including a first thread (<NUM>);
a rod (<NUM>) comprising a proximal portion, a distal portion including a pocket (<NUM>), and a second thread (<NUM>), disposed along the proximal portion (<NUM>) of the rod, that is coupled to the first thread; and
a puller wire (<NUM>) that is connected to the pocket;
a joining feature (<NUM>) secured in the pocket and attached to a proximal end of the puller wire, wherein the joining feature comprises: a first ferrule (<NUM>) joined to the proximal end of the puller wire; and a second ferrule (<NUM>) secured in the pocket and attached to the first ferrule.