Improvement of the T-shaped rod of the pulling wire for medical catheters

Abstract

The present invention describes and shows a medical probe including a generally tubular member having a distal portion coupled to the tubular member. A pull wire is disposed within the tubular member and is configured to move along the longitudinal axis to bend the distal portion relative to the longitudinal axis. An anchor is disposed within the tubular member and is connected to the pull wire such that the anchor has a T-shaped rod. The T-shaped rod includes a generally laterally extending portion and a sleeve connected to the pull wire. The T-shaped rod has a polymer member disposed on the generally laterally extending portion to increase the strength of the anchor relative to a force that causes the distal end of the medical probe to flex upon application to the pull wire.

Description

Technical Field

[0001] The subject matter disclosed herein relates to electrophysiological catheters, and more particularly to electrophysiological catheters capable of ablating cardiac tissue. Background Art

[0002] Ablating cardiac tissue has been used to treat arrhythmias. Ablation energy is typically provided to the cardiac tissue by a distal portion that can deliver ablation energy along the tissue to be ablated. Some of these catheters apply ablation energy from various electrode three-dimensional structures. Fluoroscopy can be used to visualize ablation procedures incorporating such catheters. Summary of the Invention

[0003] We have designed an end probe for use in a catheter such that the end probe can withstand a relatively large pulling force applied to a pull wire in such an end probe. In one embodiment, we have designed a medical probe that includes a generally tubular member extending from a proximal portion to a distal portion. The tubular member includes a distal portion, a pull wire, and an anchor. The tubular member extends from the proximal portion to the distal portion along a longitudinal axis. The distal portion is coupled to the tubular member proximal to the distal portion of the medical probe. The pull wire is disposed within the tubular member and is configured to move along the longitudinal axis to bend the distal portion relative to the longitudinal axis. The anchor is disposed within the tubular member and is connected to the pull wire. The anchor is formed by a T-shaped bar that includes a generally laterally extending portion and a sleeve connected to the pull wire. The T-shaped bar includes a polymer member disposed on the generally laterally extending portion.

[0004] The following features may also be combined with the end probe. For example, the polymer member may include a viscoelastic material; the viscoelastic material may include polyurethane; the polymer member may include a high-strength monofilament; the polymer member may include high-strength fibers; the high-strength fibers may include ultra-high molecular weight fibers; the T-shaped bar may include a metal member; the T-shaped bar may include a composite material, which may be a combination of a viscoelastic material and a metal; the laterally extending portion may include two lateral members extending from a central body, and the polymer member includes polyurethane sleeves disposed on each of the lateral members; the polyurethane sleeves may include tubular members having a thickness of about 0.004 inches. Brief Description of the Drawings

[0005] Although the claims that particularly point out and distinctly claim the subject matter described herein follow the description, it is believed that the subject matter will be better understood from the following description of certain examples taken in conjunction with the drawings, in which like reference numerals represent like elements and in which:

[0006] Figure 1 A side view of an embodiment of the catheter of the present invention.

[0007] Figure 2 A side cross-sectional view of the junction of the catheter body and the probe tip segment according to an embodiment of the probe of the present invention.

[0008] Figure 3 Taken along line 3-3 Figure 2 The transverse cross-sectional view of the probe shown.

[0009] Figure 4 Is Figure 2 A side cross-sectional view of the distal end of the tip segment shown.

[0010] Figure 5 A transverse cross-sectional view of the tip segment taken along line 5-5.

[0011] Figure 6 A transverse cross-sectional view of the catheter tip segment, where the pull wire is anchored to the side wall of the tip segment.

[0012] Figure 7 A longitudinal cross-sectional view of a preferred pull wire T-bar anchor.

[0013] Figure 8 Is rotated approximately 90 degrees to show the crossbar on the end Figure 7 Of the pull wire T-bar anchor longitudinal cross-sectional view.

[0014] Figure 9A A side view of an embodiment of a medical probe.

[0015] Figure 9B Is Figure 9A Of the magnified perspective side view of the medical probe.

[0016] Figure 10A Shows Figure 9A A photograph of a previous type of anchor used in.

[0017] Figure 10B Shows Figure 9A A photograph of an embodiment of the present invention used in.

[0018] Figure 11 Shows Figure 10B Another view of the anchor.

[0019] Figure 12 Shows a perspective view of another embodiment of a polymer member for improving the ability of the anchor to withstand a large pulling force when applied to a pull wire. Detailed Description

[0020] The following detailed description should be read in conjunction with the accompanying drawings, in which like numerals in different drawings refer to the same elements. The drawings (not necessarily to scale) illustrate selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates, by way of example, rather than 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.

[0021] As used herein, the term "about" or "approximately" in reference to any numerical value or range indicates a suitable dimensional tolerance that allows the collection of components or elements to achieve its intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of values of ±10% of the recited value, e.g., "about 90%" can refer to a range of values from 81% to 99%. Additionally, as used herein, the terms "patient", "host", "user", and "subject" refer to any human or animal subject, and are not intended to limit the system or method to human use, but the use of the subject invention in human patients represents a preferred embodiment.

[0022] In an embodiment of the invention, a steerable bidirectional electrode catheter is provided. As Figure 1 shown, the catheter 10 includes an elongate catheter body 12 having a proximal end and a distal end, a distal segment 14 located at the distal end of the catheter body 12, and a control handle 16 located at the proximal end of the catheter body 12.

[0023] As Figure 2 and Figure 3 shown, the catheter body 12 includes an elongate tubular structure having a single axial or central lumen 18. The catheter body 12 is flexible, i.e., bendable, but substantially non-compressible along its length. The catheter body 12 can have any suitable construction and can be made of any suitable material. A presently preferred construction includes an outer wall 20 made of polyurethane or PEBAX. The outer wall 20 preferably includes an embedded braided mesh made of stainless steel or the like to increase the torsional stiffness of the catheter body 12 such that when the control handle 16 is rotated, the distal segment 14 will rotate in a corresponding manner.

[0024] The overall length and diameter of the catheter 10 can vary depending on the application. The presently preferred catheter 10 has an overall length of about 48 inches. The outer diameter of the catheter body 12 is not critical, but preferably does not exceed about 8 French. The inner surface of the outer wall 20 is preferably lined with a stiffening tube 22, which can be made of any suitable material (preferably nylon or polyimide). The stiffening tube 22, together with the braided outer wall 20, provides improved flexural and torsional stability while minimizing the wall thickness of the catheter body 12 and thus maximizing the diameter of the central lumen 18. The outer diameter of the stiffening tube 22 is approximately the same as or slightly smaller than the inner diameter of the outer wall 20. A particularly preferred catheter 10 has an outer diameter of about 0.092 inches and a lumen 18 diameter of about 0.052 inches.

[0025] As Figure 4 and Figure 5 shown, the distal segment 14 includes a short segment of flexible tubing 24 having a first off-axis lumen 26 and a second off-axis lumen 28. The flexible tubing 24 is made of a suitable non-toxic material, which is preferably more flexible than the catheter body 20. The presently preferred material for the tubing 24 is braided polyurethane, i.e., polyurethane having a mesh of embedded braided stainless steel or similar material. Similar to the outer diameter of the catheter body 12, the outer diameter of the distal segment 14 is preferably no greater than about 7 French, more preferably about 6-1 / 2 or less.

[0026] The off-axis lumens 26, 28 extend through diametrically opposed halves of the distal segment 14. In an 8 French or 7 French diameter catheter where the distal segment is 6-1 / 2 French, the off-axis lumens 26 and 28 preferably have a diameter in the range of about 0.018 inches to about 0.025 inches, more preferably about 0.018 inches to about 0.022 inches. By using two rather than three lumens along a single diameter, the present design retains the simplified construction of the unidirectionally flexible and steerable catheter described in U.S. Patent Re 34,502, which is incorporated herein by reference. However, it should be understood that additional lumens can be provided in the distal segment. As described in U.S. Patent 6,171,277, the disclosure of which is incorporated herein by reference, the distal segment 14 can include four lumens, where two lumens have a larger diameter of about 0.035 inches and two lumens have a smaller diameter of about 0.019 inches. Leads for electrodes, thermocouple wires, and / or electromagnetic sensor cables can extend through lumens that are different from the lumens through which each of the pull wires extends. Thus, the present invention can employ two or more lumens in the distal segment 14.

[0027] Figure 2Shown is a preferred manner for attaching the catheter body 12 to the distal segment 14. The proximal end of the distal segment 14 includes a peripheral notch 34 that receives the inner surface of the outer wall 20 of the catheter body 12. The distal segment 14 and the catheter body 12 are attached by glue or a similar material. However, before the distal segment 14 and the catheter body 12 are attached together, the stiffening tube 22 is inserted into the catheter body 12. The distal end of the stiffening tube 22 is fixedly attached near the distal end of the catheter body 12 by forming an adhesive joint using polyurethane glue or the like. Preferably, a short distance, such as about 3 mm, is provided between the distal end of the catheter body 12 and the distal end of the stiffening tube 22 to allow space for the catheter body 12 to receive the notch 34 of the distal segment 14. A force is applied to the proximal end of the stiffening tube 22, and while the stiffening tube 22 is in compression, a first adhesive joint (not shown) is made between the stiffening tube 22 and the outer wall 20 by a quick-drying glue (such as super glue). Thereafter, a second adhesive joint is formed between the stiffening tube 22 and the proximal end of the outer wall 20 using a slower-drying but stronger glue such as polyurethane.

[0028] In the illustrated embodiment, the distal end of the distal segment 14 carries a distal electrode 38 (see Figure 1 and Figure 4 ). The annular electrode 40 is mounted along the length of the distal segment 14 (see Figure 4 ). The length of the annular electrode 40 is not critical, but is preferably from about 0.5 mm to about 3 mm. If desired, additional annular electrodes may be provided. If multiple annular electrodes are used, they may be spaced apart in any manner as needed, provided that their edges do not touch.

[0029] As Figures 2 - 5 shown, the distal electrode 38 and the annular electrode 40 are each connected to a separate lead 30. Each lead 30 extends through a second off-axis lumen 28 in the distal segment 14 ( Figure 5 ), through the central lumen 18 in the catheter body 12 ( Figure 3 ), and through the control handle 16. The proximal end of each lead 30 extends out of the proximal end of the control handle 16 and is connected to a suitable connector that can be inserted or otherwise connected to a suitable monitor, energy source, etc.

[0030] The lead wire 30 is connected to the distal electrode 38 and the annular electrode 40 by any conventional technique. The connection of the lead wire 30 to the distal electrode 38 is preferably achieved by solder or the like. The connection of the lead wire 30 to the annular electrode 40 is preferably achieved by first preparing a small hole through the tube 24. For example, this hole can be formed by inserting a needle through the tube 24 and heating the needle sufficiently to form a permanent hole. Then, the lead wire 30 is pulled through this hole using a micro-hook or the like. Then, any coating at the end of the lead wire 30 is stripped and the end is soldered to the underside of the annular electrode 40, which is then slid into position above the hole and fixed in place using polyurethane glue or the like.

[0031] Also as Figures 2 - 5 shown, two pull wires 32 extend through the catheter 10. Each pull wire 32 extends from the control handle 16 through the central lumen 18 in the catheter body 12 ( Figure 3 ) and into one of the off-axis lumens 26 and 28 in the distal segment 14 ( Figure 5 ). As detailed below, the proximal movement of the proximal end of each pull wire 32 is pre-defined within the control handle 16, and the distal end of each pull wire 32 is anchored within the distal segment 14.

[0032] Each pull wire 32 is made of any suitable metal such as stainless steel or nitinol. Preferably, each pull wire 32 has a coating, such as a low-friction polymer coating. Each pull wire 32 has a diameter preferably in the range of about 0.006 inches to about 0.010 inches. Preferably, the two pull wires 32 have the same diameter.

[0033] Each pull wire 32 is anchored near the distal end of the distal segment 14. In the Figure 4 shown embodiment, the pull wire 32 is anchored to the distal electrode 38 by welding or the like.

[0034] Alternatively, the pull wire 32 in the first off-axis lumen 26 can be anchored to the side wall of the distal segment 14. As Figure 7As shown in FIGS. 0 to 9, the pull wire 32 is preferably attached by an anchor 44 fixedly attached to the distal end of the pull wire 32. The anchor 44 is preferably formed by a metal tube 45 (e.g., a cannula connected to the pull wire stock), which is fixedly attached to the distal end of the pull wire 32, for example, by crimping or welding. The tube has a segment that extends a short distance beyond the pull wire 32. A cross beam 47 made of small segments of flat, stainless steel strip, etc. is soldered or welded to the distal end of the metal tube in a transverse arrangement. This produces a T-shaped rod anchor 44. A notch is formed in the side of the terminal segment 14, thereby creating an opening in the offset lumen 26 to carry the pull wire 32. The cross beam 47 is located transversely within the notch. Since the length of the strip forming the cross beam 47 is longer than the diameter of the opening within the offset lumen 26, the anchor 44 cannot be fully pulled into the offset lumen 26. The notch is then sealed with polyurethane glue, etc. to produce a smooth outer surface. The glue flows into the offset lumen 26 to fully secure the anchor. Additional lumens may be provided to allow leads, irrigation fluids, or other articles (not shown) to pass through to the distal end. Other devices for anchoring the pull wire 32 in the terminal segment 14 will be recognized by those skilled in the art and are included within the scope of the present invention.

[0035] Referring back to Figure 1 and Figure 2 , the catheter 10 also includes two compression coils 46, each compression coil being in a surrounding relationship with a corresponding pull wire 32. Each compression coil 46 is made of any suitable metal such as stainless steel. Each compression coil 46 is tightly wound on its own to provide flexibility, i.e., bendability, but resists compression. The inner diameter of each compression coil 46 is slightly larger than the diameter of the pull wire 32 associated therewith. For example, when the diameter of the pull wire 32 is about 0.007 inches, the corresponding compression coil 46 preferably has an inner diameter of about 0.008 inches. The coatings on the pull wires 32 enable them to slide freely within the compression coils 46. The outer surface of each compression coil 46 is covered with a flexible, non-conductive sheath 48 over most of its length to prevent contact between the compression coil 46 and the lead 30 within the central lumen 18. A non-conductive sheath 48 made of thin-walled polyimide tubing is currently preferred. In a preferred embodiment, the compression coils 46 and the pull wires 30 are disposed within the lumen 30, where the lumen 48 is used as a channel for wires or as a flushing flow path.

[0036] As Figure 2As shown, at the distal end of the catheter body, two compression coils 46 are diametrically opposed and positioned within the stiffening tube 22 and the gasket 36 such that they can be aligned with the two off-axis lumens 26, 28 in the distal segment 14. The compression coils 46 and the stiffening tube 22 are sized such that the compression coils 46 fit tightly and slidably within the stiffening tube 22. With this design, the lead 30 distributes itself around the two compression coils 46 without misaligning the coils.

[0037] The compression coils 46 are fixed within the catheter body 12 using a polyurethane adhesive or the like. The proximal end of each compression coil 46 is anchored to the proximal end of the stiffening tube 22 in the catheter body 12 by an adhesive joint (not shown). When the stiffening tube 22 is not used, each compression coil is directly anchored to the outer wall 20 of the catheter body 12.

[0038] Still referring to Figure 2 , the distal end of each compression coil 46 is anchored to the distal end of the stiffening tube 22 in the catheter body 12 by an adhesive joint 52, or when the stiffening tube 22 is not used, it is directly attached to the distal end of the outer wall 20 of the catheter body 12. Alternatively, the distal end of the compression coil 46 can extend into the off-axis lumens 26, 28 of the distal segment 14, and its distal end is anchored to the proximal end of the distal segment 14 by an adhesive joint. The lead 30 can also be anchored in the adhesive joint. However, if desired, a tunnel in the form of a plastic tubing or the like around the lead can be provided at the adhesive joint to allow the lead to slide within the adhesive joint.

[0039] The two adhesive joints preferably include a polyurethane adhesive or the like. The adhesive can be applied using a syringe or the like through a hole formed between the outer surface of the catheter body 20 and the central lumen 18. This hole can be formed, for example, by a needle that pierces the outer wall 18 and the stiffening tube 22, and the needle is sufficiently heated to form a permanent hole. Then the adhesive is introduced through the hole to the outer surface of the compression coil 46 and wicked around the outer circumference to form an adhesive joint around the entire circumference of each sheath 48 surrounding each compression coil 46.

[0040] As Figure 2 and Figure 5 best shown, within the off-axis lumens 26, 28, each pull wire 32 is surrounded by a plastic sheath 42, which is preferably made of a suitable low-friction polymer. When the distal segment is flexed, the plastic sheath 42 prevents the pull wire 32 from cutting into the wall of the distal segment 14. Each sheath 42 terminates near the distal end of each pull wire 32. Alternatively, each pull wire 32 can be surrounded by a compression coil, the turns of which are longitudinally extensible relative to the compression coils extending through the catheter body, such that this surrounding compression coil can both bend and compress.

[0041] The longitudinal movement of the pull wire 32 that causes the distal segment 14 to flex is accomplished by manipulation of the control handle 16. A two-way control handle suitable for the present invention is shown in FIGS. 9-24 of U.S. Patent 7,377,906, the entire text of which is incorporated herein by reference.

[0042] See Figure 9A and 9B , we have designed the configuration of the anchor 44 to allow a greater pulling force to be applied to the pull wire. In this configuration, the medical probe 100 includes at least a generally tubular member 24 extending from a proximal portion to a distal portion. The tubular member 24 includes a distal portion 102, a pull wire 32, and an anchor 44. The tubular member 24 extends from the proximal portion to the distal portion along a longitudinal axis L-L. The distal portion 102 is coupled proximally to the tubular member 24 at the distal portion of the medical probe 100. The pull wire 32 is disposed within the tubular member 24 and is configured to move along the longitudinal axis L-L to bend the distal portion 102 relative to the longitudinal axis L-L. The anchor 44 is disposed within the tubular member 24 and is connected to the pull wire 32 via a T-shaped rod 47. The T-shaped rod 47 includes generally laterally extending portions in the form of wings 47a and 47b and a sleeve 45 connected to the pull wire 32. This configuration of the anchor 44 can be seen in Figure 10A in.

[0043] We improve the Figure 10A anchor 44 by a polymer member 48 disposed on the generally laterally extending portion 47 of the T-shaped rod to obtain the new anchor configuration 44' as shown herein in Figure 10B . As shown separately in Figure 11 , the anchor 44' includes two generally laterally extending portions 47a and 47b and a sleeve 45 fixedly connected to the pull wire 32, wherein a polymer member 49 (shown in amber material) is disposed on each of the lateral wings 47a and 47b.

[0044] In one embodiment, the polymer member 49 may include a viscoelastic material such as, for example, polyurethane. By implementing the polymer member 49, the anchor 44' allows a greater pulling force of the pull wire 32 to be tolerated. As shown in the table, the average pulling force is increased by about 36% for the sample numbers of the medical probes using the anchor 44 compared to the sample numbers of the medical probes using the anchor 44'.

[0045]

[0046] In an alternative embodiment of the anchor 44', the polymeric member 49 may include high-strength monofilaments or high-strength fibers 49', such as, for example, ultra-high molecular weight fibers for the anchor 44". The monofilaments or fibers 49' of the anchor 44" are configured to wrap around the central body 45 at least once and abut the extensions 47a and 47b, wherein the free ends of the fibers 49' extend distally from the T-bar 47 into the remaining lumen segment portion 26' of the traction wire lumen 26 by a predetermined distance of about.100 inches (or about 2.5 mm). Additionally, the polymeric member 49' is then secured within the remaining lumen segment 26' by glue or the like. The tension from the anchor 45 is thus distributed within the slots 29 formed in the tubular member 24 and within the lumen segment 26'. The T-bar 47 may include a metallic member, such as a biocompatible metal (including, for example, stainless steel) or an alloy of such a metal. Alternatively, the T-bar 47 may include a composite of metal and polymer or a polymer alone. Although the T-bar 47 is shown as having two generally symmetric extensions 47a and 47b extending from the central body 45, the T-bar 47 may include other forms of the geometry of the extensions and a single straight extension protruding from the central sleeve body 45.

[0047] The foregoing description has been presented with reference to the presently preferred embodiments of the invention. Those skilled in the art to which this invention pertains will know that changes and modifications may be made to the described structure without departing intentionally from the principles, spirit, and scope of the invention.

[0048] Accordingly, the specific embodiments described above should not be construed as limited to the precise structures shown and described in the drawings, but rather should be construed as consistent with and supportive of the following claims, which claims have the full and fair scope of the invention.

[0049] Any examples or embodiments described herein may also 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 regarded as mutually exclusive. With reference to the teachings herein, various suitable ways in which the teachings herein may be combined will be apparent to those skilled in the art.

[0050] Exemplary embodiments of the subject matter contained herein have been shown and described, and further improvements of the methods and systems described herein can be achieved with appropriate modifications without departing from the scope of the claims. In addition, where the above methods and steps represent specific events occurring in a specific order, it is intended herein that certain specific steps need not necessarily be performed in the order described, but can be performed in any order, as long as the steps enable the embodiment to achieve its intended purpose. Accordingly, if there are variations of the present invention and such variations fall within the scope of the substance of the disclosure or equivalent of the present invention found in the claims, this patent is intended to cover such variations as well. Many such modifications will be obvious to those skilled in the art. For example, the examples, embodiments, geometries, materials, dimensions, ratios, steps, etc. described above are illustrative. Therefore, the claims should not be limited by the specific details of the structures and operations shown in this written description and the drawings.

Claims

1. A medical probe, comprising: A generally tubular member that extends along a longitudinal axis from a proximal portion to a distal portion; A distal portion that is coupled proximally to the tubular member at the distal portion of the medical probe; A pull wire that is disposed within the tubular member and configured to move along the longitudinal axis to bend the distal portion relative to the longitudinal axis; An anchor that is disposed within the distal portion and connected to the pull wire at a notch formed in a side of the distal portion, wherein the anchor has a T-shaped rod that includes two generally laterally extending portions in the form of two lateral wings extending from a central body and a sleeve connected to the pull wire, the T-shaped rod has a polymeric member, and for each of the two lateral wings, the polymeric member is located over the entire lateral wing, and wherein the notch is sealed with a polyurethane adhesive to produce a smooth outer surface and the anchor is fully secured with the polyurethane adhesive.

2. The medical probe according to claim 1, wherein the T-shaped rod comprises a metal member.

3. The medical probe according to claim 1, wherein the T-shaped rod comprises a composite material.

4. The medical probe according to claim 3, wherein the composite material comprises a combination of a viscoelastic material and a metal.

5. The medical probe according to claim 1, wherein the polymer member comprises a polyurethane sleeve disposed on each of the two transverse wings.

6. The medical probe according to claim 5, wherein the polyurethane sleeve comprises a tubular member having a thickness of about 0.004 inches.

7. The medical probe according to claim 1, wherein the pulling wire comprises a stainless steel wire.

Images