Mechanism for manipulating a pull wire

Description

FIELD

[0001] The subject matter disclosed herein relates to a mechanism for deflecting a distal portion of a catheter.BACKGROUND

[0002] Catheter-deflection technology and improvements thereto, such as ergonomic improvements, remain an ongoing concern in the medical arts.

[0003] EP0928601A1 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. US2016 / 058975A2 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.SUMMARY OF THE DISCLOSURE

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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: Figure 1 depicts a catheter having a catheter body and a handle with a deflection knob; Figure 2 depicts a cross section of a segment of the catheter body of Figure 1; Figure 3 depicts a perspective view of a subassembly of a catheter handle; Figure 4 depicts a detail view of the distal end of the subassembly of Figure 3 as indicated by the circle labeled "Detail 4" in Figure 3; Figure 5 depicts an exploded view of the subassembly of Figure 3; and Figure 6 depicts a section view of a knob component of the subassembly of Figure 3. MODES OF CARRYING OUT THE INVENTION

[0009] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are identically numbered. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

[0010] As used herein, the terms "about" or "approximately" for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, "about" or "approximately" may refer to the range of values ±10% of the recited value, e.g. "about 90%" may refer to the range of values from 81% to 99%. In addition, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject and are not intended to limit the systems or methods to human use, although use of the subject invention in a human patient represents a preferred embodiment.

[0011] Figure 1 shows a catheter 10 including an elongated catheter body 12 having proximal and distal ends, 14 and 16, respectively. A control handle 18 including a control knob 20 may be disposed at the proximal end of the catheter body. As seen in Figure 2, catheter body 12 comprises an elongated tubular construction having an axial or central lumen 22. Catheter body 12 is flexible, i.e., deflectable, but substantially non compressible along its length. Catheter body 12 can be of any suitable construction and made of any suitable material. A presently preferred construction comprises an outer wall 24 made of polyurethane or PEBAX ®< . The outer wall 24 may comprise an embedded braided mesh of stainless steel or the like to increase torsional stiffness of catheter body 12.

[0012] As shown in Figure 2, a puller wire 64 may be disposed in lumen 22 of catheter body 12. Puller wire 64 is provided for deflection of a portion of the catheter, e.g., the distal end of catheter body 12. As such, the puller wire 64 extends through the catheter body 12 whereupon it may be attached to the distal end of the catheter in lumen 22. A proximal end of puller wire 64 may be anchored to the control handle 18, particularly to a component that may be manipulated via movements of knob 20 as explained below. Puller wire 64 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 64. Puller wire 64 may have a diameter ranging from, e.g., about 0.152 mm to 0.254 mm (0.006 to about 0.010 inch).

[0013] Longitudinal movement of the puller wire 64 relative to the catheter body 12, results in deflection of the distal end of catheter body 12. Such movement may be accomplished by suitable manipulation of the control handle 16, as described in, e.g., U.S. Patent Nos. Re 34,502 and 5,897,529. Another mechanism for imparting longitudinal movement to puller wire 64 is described with reference to Figures 3 - 6.

[0014] Figure 3 shows a subassembly 100 of a handle mechanism for use with a deflectable catheter. Subassembly 100 includes a control knob 120, a rod 122, and a stationary component, e.g., collar 124. As shown, knob 120, rod 122, and collar 124 each have a cylindrical form and are arranged concentrically with each other about longitudinal axis 112 of subassembly 100. Such concentricity is not required, however, to practice the disclosed subject matter. Rod 122 may be coupled to control knob 120 such that rotation of knob 120 about axis 112 causes linear motion, i.e., translation of rod 122 relative to knob 120 along or parallel to axis 112. Collar 124 may be maintained in a stationary state relative to knob 120 and rod 122, such that it may be configured to restrict rotational motion of rod 122 about axis 112. As such, rod 122 can be pulled into collar 124 by rotating knob 120 one way (e.g., clockwise) and pushed out of collar 124 by rotating knob 120 the other way (e.g., counterclockwise).

[0015] Threads may be used to impart linear motion to rod 122 via application of rotational forces to knob 120. Such a mechanism also prevents linear forces applied to rod 122 from causing knob 120 to rotate. As seen in Figure 5, which is an exploded view of subassembly 100 with some components removed for clarity, female threads 126 may be disposed on an outer surface 146 of rod 122 at proximal end 140. With further reference to Figure 6, male threads 127 may be disposed on an internal surface of knob 120. For example, knob 120 may define a bore therethrough and the male threads may be disposed about the circumference of the bore. The coupling of knob 120 and rod 122 via their respective threads allow for linear motion of rod 122 to be caused by rotation of knob 120. Of course, the same cause and effect may be realized by providing rod 122 with male threads and knob 120 with female threads.

[0016] Rod 122 is connected to a puller wire 164, best seen in Figure 4, which is a detail view of the distal end 142 of rod 122. The connection is realized via a joining feature 130 connected to distal end 142. Preferably, joining feature 130 may include between one and three ferrules, e.g., two ferrules. As seen in Figure 4, a first ferrule 132 is be attached, e.g., crimped, onto puller wire 164, and a second ferrule 134 is attached, e.g., crimped, onto first ferrule 132. Second ferrule 134 is coupled to distal end 142 of rod 122 by attaching it thereto via a pocket 136 formed in distal end 142. For example, second ferrule 134 may be bonded or glued in pocket 136. In preferred embodiments, first ferrule 132 may be fabricated from stainless steel and second ferrule 134 may be fabricated from brass. Joining feature 130 provides a robust joint between rod 122 and puller wire 164 because the surface area of second ferrule 134 in pocket 136 is substantially greater than the surface area of a proximal portion of wire 164 that might otherwise be directly attached therein. As such, friction forces and other bonding forces between pocket 136 and second ferrule 134 are greater than they would otherwise be if a distal portion of wire 164 were directly attached to rod 122 without ferrule 134. First ferrule 132 also contributes to the robustness of the joint. As shown, first ferrule 132 has a cylindrical form, which allows it to be crimped onto the proximal end of wire 164 without pinching it, damaging it, or otherwise causing a stress concentration that could lower the maximum tensile load or number of cycles that wire 164 would otherwise be able to handle until failure.

[0017] Because puller wire 164 is connected to rod 122 via joining feature 130, linear motion of rod 122 effected by rotation of knob 120 causes a corresponding linear motion or displacement of puller wire 164. By connecting puller wire 164 to another object, that object may be manipulated by movements of puller wire 164 caused by rotations of knob 120.

[0018] A catheter body of a catheter, such as catheter body 12 of catheter 10, may be connected at its proximal end to handle subassembly 100, e.g., directly or indirectly to the stationary component, e.g., collar 124. Preferably, distal end 14 of catheter body 12 has an internal diameter slightly smaller to slightly larger than the outer diameter of collar 124 to permit attachment via, e.g., an interference fit, bonding with an adhesive, or both. Because rod 122 may be advanced or retracted through collar 124, the outer diameter of rod 122 is smaller than the inner diameter of collar 124, indicating that the outer diameter of rod 122 is also smaller than the inner diameter of catheter body 12. As such, puller wire 164 may extend through catheter body 12, from its proximal end 14 to its distal end 16. Puller wire 164 may further be anchored at the distal end 16 of catheter body 12, e.g., via a glue joint. Accordingly, translating puller wire 164 proximally causes distal end 16 of catheter body 12 to deflect, e.g., toward the dotted line shape shown in Figure 1. Subsequent distal translation of puller wire 164 causes distal end 16 of catheter 12 to return toward its original shape.

[0019] Rod 122 additionally defines an internal passageway 144 therethrough. Additional catheter structures that pass through handle subassembly 100 may pass through passageway 144. For example, a lead wires 148 and an irrigation tube 150 may be disposed through passageway 144.

[0020] By virtue of the embodiments illustrated and described herein, Applicant has devised a method and variations thereof for using a catheter, such as catheter 10 including subassembly 100, the method including steps of rotating a deflection knob (e.g., knob 120), translating a rod (e.g., rod 122), and displacing a puller wire (e.g., 164). 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.

[0021] 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.

[0022] Having shown and described exemplary embodiments of the subject matter contained herein, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications without departing from the scope of the claims, which define the invention.

Claims

1. A catheter, comprising: a deflection knob (120) including a first thread (127); a rod (122) comprising a proximal portion, a distal portion including a pocket (136), and a second thread (126), disposed along the proximal portion (140) of the rod, that is coupled to the first thread; and a puller wire (164) that is connected to the pocket; a joining feature (130) secured in the pocket and attached to a proximal end of the puller wire, wherein the joining feature comprises: a first ferrule (132) joined to the proximal end of the puller wire; and a second ferrule (134) secured in the pocket and attached to the first ferrule.

2. The catheter of claim 1, in which the second thread is disposed on an outer surface (146) of the rod.

3. The catheter of claim 1, in which the first ferrule is crimped onto the proximal end of the puller wire.

4. The catheter of claim 1, in which the second ferrule is crimped onto the first ferrule.

5. The catheter of claim 1, in which the second ferrule is bonded to the pocket.

6. The catheter of claim 5, in which the first thread comprises a female thread, preferably in which the second thread comprises a male thread.

7. The catheter of claim 5, in which the first thread comprises a male thread, preferably in which the second thread comprises a female thread.

8. The catheter of claim 5, in which the deflection knob includes a longitudinal bore having a surface and the first thread is disposed on the surface.

9. The catheter of claim 8, in which a portion of the proximal portion of the rod is disposed through the longitudinal bore.

10. The catheter of claim 9, further comprising a handle (100) including the deflection knob, the rod, and a stationary component (124).

11. The catheter of claim 10, further comprising a catheter body (12) having a proximal end connected to the stationary component and a deflectable distal end (16) connected to a distal end of the puller wire.

12. The catheter of claim 11, in which the rod defines therethrough an internal passageway (144) and the catheter further comprises a structure extending through the internal passageway.

13. The catheter of claim 12, in which the structure comprises an irrigation tube (150).

14. The catheter of claim 13, in which the structure comprises a wire (148).

15. The catheter of claim 1, in which the first ferrule comprises stainless steel, preferably in which the second ferrule comprises brass.