Pull Cable Management for Steerable Catheters

Abstract

The steerable catheter has a transducer located at a flexible distal tip and coupled to the catheter's handle via an insertion tube. The flexible distal tip is controlled by multiple articulation pull cables extending from an articulation control in the handle to the distal end of the distal tip, such that when one articulation pull cable is pulled and the opposing joint pull cable goes slack, the flexible distal tip bends toward the joint pull cable under tension. To minimize pulling resistance over time while providing flexibility for the insertion tube, an inserter having a pull cable lumen is located within the insertion tube to separate each joint pull cable from each other and from other cables connecting the transducer to the handle.

Description

[Technical field]

[0001] The present invention relates to the field of medical instruments, and more particularly to methods and systems for managing articulated pull cables in steerable catheters or other steerable instruments such as endoscopes, gastroscopes, and transesophageal echocardiography (TEE) probes. [Background technology]

[0002] Catheters are commonly used to place elements within passageways within a patient's body, monitor certain biometrics, perform surgical procedures, administer medications, etc. Steerable catheters, having articulating distal ends, have been developed to navigate through passageways.

[0003] 1A-1C show an exemplary prior art steerable catheter 100. The catheter 100 has a handle 110, an insertion tube 120, a flexible distal end 130, and a transducer 170. The transducer 170 acquires imaging data via ultrasound. Other devices may be substituted for the transducer 170, which may receive optical images of the patient's biometrics and / or internal passages, or perform tasks such as dissection, removal of obstructions, administration of medication, etc. To perform these operations, the handle 110 is coupled to a medical instrument controller (not shown) and coupled to the transducer 170 via one or more transducer cables 150 in the insertion tube 120. In the above example of the ultrasound transducer 170, the steerable catheter 100 may be an ultrasound probe, such as a transesophageal echocardiography (TEE) ultrasound probe, a transvaginal ultrasound probe, etc., for use with an ultrasound system.

[0004] 1B shows the catheter 100 in a "neutral" state in which the flexible distal tip 130 is not bent or twisted. The handle 110 includes an articulation controller 115 that is coupled to the flexible distal tip 130 via articulation pull cables 160a, 160b (collectively, articulation pull cables 160) that extend through the insertion tube 120 to the flexible distal tip 130.

[0005] As shown in Cross Section 2A, these joint pull cables 160 are fixedly attached to terminators 175 located at the transducer end of the flexible distal tip 130 and can be selectively tensioned / pulled by the joint controller 115.

[0006] As shown, the articulation pull cables 160a, 160b are located opposite each other at the perimeter region of the terminator 175. This allows two degrees of freedom for adjusting the orientation of the flexible distal end 130. In some embodiments, the flexible distal end 130 includes structural details that limit bending of the flexible distal end 130 in two opposite directions. When the upper cable 160b is pulled through the articulation controller 115 and the lower cable 160a is correspondingly slack, the tension, through the rotation 118 of the articulation controller 115, causes the flexible distal end 130 to twist upward as illustrated in FIG. 1A. Reversing the rotation 119 on the articulation controller 115 causes the lower cable 160a to pull and the upper cable 160b to slack, causing the flexible distal end 130 to twist downward as shown in FIG. 1C.

[0007] Although two articulated pull cables 160a, 160b are shown, the steerable catheter may include more cables positioned around the terminator 175 to provide additional degrees of freedom of movement. Typically, four articulated pull cables are provided to provide for horizontal and vertical bending of the flexible distal end 130.

[0008] In some embodiments, as shown in FIG. 3, a pull cable lumen 165 is provided through the flexible distal end 130 to provide a more uniform tension within the flexible distal end 130 as the articulation pull cable 160 is tensioned / pulled.

[0009] For proper articulated steering, the flexible distal end 130 must be more flexible than the insertion tube 120, but the insertion tube 120 must provide sufficient flexibility to minimize discomfort to the patient as the insertion tube 120 moves through the patient's internal vasculature. Thus, a single lumen 190 is provided for routing the transducer cable 150 and the articulation pull cable 160, as shown in the cross-sectional view of FIG. 2B, such that the flexibility of the insertion tube 120 may be determined primarily by the dimensions and composition of the material forming the cylindrical insertion tube 120. The single lumen 190 also facilitates the insertion / routing of the cables 150, 160 into the insertion tube 120. However, the lack of this structure in the lumen 190 introduces issues that affect the reliability and lifespan of the steerable catheter 100, as will be described in more detail below. Summary of the Invention [Problem to be solved by the invention]

[0010] It is an object of the present invention to provide a more robust catheter or similar elongated medical instrument device design by providing a structure for cable routing within the insertion tube of a steerable catheter or (elongated) device without significantly affecting the flexibility of the insertion tube. [Means for solving the problem]

[0011] To better address one or more of these concerns, in one embodiment of the present invention, the insertion tube may include multiple inserts spaced along the insertion tube from the handle to the distal end, and each insert of the multiple inserts may include multiple lumens having one or more transducer cable lumens and multiple pull cable lumens, the multiple lumens separating each of the transducer cables and multiple articulation pull cables from one another.

[0012] The invention will now be explained in further detail, by way of example, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0013] [Figure 1A] 1 illustrates an exemplary prior art steerable catheter. [Figure 1B] 1 illustrates an exemplary prior art steerable catheter. [Figure 1C] 1 illustrates an exemplary prior art steerable catheter. [Figure 2A] 1 shows an exemplary cross-section of a prior art steerable catheter. [Figure 2B] 1 shows an exemplary cross-section of a prior art steerable catheter. [Diagram 3] 1 shows an exemplary prior art flexible distal end of a steerable catheter. [Figure 4] 1 illustrates an exemplary insert for placement within the insertion tube. [Diagram 5] 1 shows multiple inserts within the insertion tube. [Figure 6] 1 shows an alternative insert structure. [Figure 7] 1 shows an alternative insert structure. [Figure 8] 1 shows a string of components for insertion into an insertion tube. [Figure 9] 1 shows an alternative insert structure. [Figure 10] 13 shows an exemplary flow diagram for assembling a steering catheter having an articulation pull cable support within an insertion tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Throughout the drawings, the same reference numbers indicate similar or corresponding features or functions.The drawings are included for illustrative purposes and are not intended to limit the scope of the invention.

[0015] In the following description, for purposes of explanation and not limitation, specific details are set forth, such as specific architectures, interfaces, techniques, etc., to provide a thorough understanding of the concepts of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. Similarly, the text of this description is directed to exemplary embodiments as illustrated in the drawings, and is not intended to limit the claimed invention beyond the limitations expressly contained in the claims. For purposes of simplicity and clarity, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0016] It will be understood that the implementation of the invention described below in a catheter for use in a blood vessel is merely exemplary, and the scope of the invention includes any steerable device, such as an elongated medical device, including a catheter, intended for insertion into the vessels, ducts, passageways, and cavities of the body and having a steerable distal portion for use in imaging, medical procedures, implant placement, implant removal, and the like. Non-limiting examples of other such medical devices falling within the scope of the present invention are endoscopes, gastroscopes, transvaginal ultrasound probes, and transesophageal echocardiography (TEE) ultrasound probes. In embodiments including TEE, the transducer 170 is, of course, an ultrasound transducer. The present invention described below for use in an exemplary catheter may be readily implemented in these other elongated medical devices, and thus enjoy similar benefits and improvements over prior art configurations.

[0017] As discussed above, prior art catheters are prone to premature failure due to the unstructured lumen 190 of the insertion tube 120, as shown in FIG. 2B. After repeated use, the cables 150, 160 often become entangled with each other, causing increased resistance to tension and slack in the joint pull cables 160. This increased resistance can often lead to premature failure of the catheter 100 due to the inability to pull or release one of the joint pull cables 160. This increased resistance can be reduced by encasing each joint pull cable 160 in a protective sleeve that is sized to allow the joint pull cable 160 to be pulled and slackened, and has sufficient rigidity to withstand deformation by the other cables. However, such a protective shield on each joint pull cable 160 would significantly affect the overall flexibility of the insertion tube 120.

[0018] 4 illustrates an example insert 400 that provides structure within the insertion tube 420. The example insert 400 includes a transducer lumen 450 through which one or more transducer cables 150 pass and multiple pull cable lumens 460 through which multiple steering cables 160 pass. As shown, the pull cable lumens 460 are C-shaped and form an enclosed volume when located within the insertion tube 420.

[0019] As with a conventional catheter as shown in FIG. 1, a transducer cable 150 is coupled to a transducer 170 at the flexible distal end 130 of the catheter and is coupled to the handle 110 for coupling to a medical control device (not shown) within the handle 110 or external to the handle 110. A joint pull cable 160 is fixedly attached to a terminator 175 at the distal end of the flexible distal end 130 and is coupled to an articulation control element 115 within the handle 110. Depending on the configuration of the control element 115, the joint pull cable 160 may be fixedly attached to the control element 115 or movably attached to the control element 115, for example, a pair of joint pull cables 160 having a continuous cable around a wheel that is rotated by the control element 115 to apply tension to one joint pull cable of the pair and slack to the other joint pull cable. An insertion tube 120 is attached to the handle 110 and the flexible distal end 130.

[0020] Non-limiting examples of transducers 170 according to the present disclosure are electromechanical transducers, electroacoustic transducers such as ultrasound (or US) transducers. Lumens 450, 460 provide isolation of joint pull cables 160 from transducer cable 150 and from each other. Pull cable lumens 460 are sized to allow free movement of joint pull cables 160. In embodiments of the invention, joint pull cables 160 or pull cable lumens 460, or both, may be coated with a lubricious material to facilitate movement of the joint pull cables through the pull cable lumens. In some embodiments, the insert comprises a lubricious material to facilitate insertion of the insert into the insertion tube 420. In some embodiments, the insert comprises a high temperature elastic material.

[0021] The inserts 400 may extend the entire length of the insertion tube 420, but such a construction may hinder the flexibility of the insertion tube 420. Therefore, in an embodiment of the present invention, multiple inserts 400 are positioned along the length of the insertion tube, as shown in Figure 5. To prevent displacement or rotation of each insert, the inserts 400 may be attached to the insertion tube 420 using heat staking, RF welding, or other attachment techniques.

[0022] 6 and 7 show an alternative construction of the insert 400. In Fig. 6, a surrounding pull cable lumen 460 is provided for each articulation pull cable 160 to facilitate assembly. In this embodiment, the transducer cables 150, articulation pull cables 160, and the insert 400 can be pre-assembled as a string of components that are later surrounded by an insertion tube 420, as described in further detail below.

[0023] 7 illustrates an example of an embodiment in which the transducer cable 150 is embedded in an insert 400. That is, each insert 400 is molded or otherwise formed around the transducer cable 150 such that the cable 150 is fixedly attached to each insert 400. In this embodiment, a closed transducer cable lumen 450 is formed by the cable 150 as each insert is formed.

[0024] 8 shows an example string of components 800 having a transducer cable 150 embedded in each of a number of inserts 400. Also embedded in each insert 400 is a draw wire 850. The draw wire 850 may be used to pull the string 800 through the insert tube 420 to create the assembly shown in FIG.

[0025] If the insert 400 includes enclosed pull cable lumens 460 as shown in FIG 6, the joint pull cables 160 can be strung through the pull cable lumens 460 of this string of components 800. Alternatively, if the insert 400 has open pull cable lumens 460 as shown in FIG 7, the joint pull cables 160 can be disposed within each pull cable lumen 460 of the insert 400 when a string of components similar to the string of components 800 is drawn into the insertion tube 420.

[0026] 9 illustrates an example of an insert configured to capture each joint pull cable 160 when positioned within the pull cable lumen 460. As shown, the insert 400 includes a trough having an opening 960 that is slightly smaller than the diameter of the joint pull cable 160. In this embodiment, the insert 400 has a resilient material that allows a larger joint pull cable 160 to be inserted through the smaller opening 960. Once inserted, the joint pull cable 160 is captured by the pull cable lumen 460 within the pliable material as it returns to its original state with the opening 960 smaller than the diameter of the joint pull cable 160.

[0027] 10 shows an example flow diagram 1000 for assembling a steering catheter having an articulation pull cable support within an insertion tube. Those skilled in the art will recognize that the illustrated order of steps is provided for ease of understanding and that the steps may be performed in a different order and / or some steps may be performed simultaneously. Those skilled in the art will also recognize that, except for placing an insert having an articulation pull cable and a transducer cable lumen within the insertion tube, the assembly of the steering catheter is consistent with known prior art that does not require detailed description herein.

[0028] At 1010, a plurality of inserts having pull cable lumens are obtained. These may be preformed inserts or may be created by extrusion or molding around the draw wire and / or transducer cables. At 1015, a draw wire is attached to each insert, and at 1020, one or more transducer cables are routed through each insert. As mentioned above, steps 1010, 1015, and 1020 may be performed simultaneously, such as when the inserts are co-extruded onto the draw wire and transducer cables.

[0029] At 1025, the articulation pull wires are routed through the pull cable lumens of each insert. If the pull cable lumens are troughs, the articulation pull cables may be temporarily held in place until the insert is about to be retracted into the insertion tube.

[0030] At 1030, a draw wire is threaded through the insertion tube, and at 1035, the draw wire is pulled to draw the assembly of the insert, transducer cable, and articulation pull cable into the insertion tube. In an alternative embodiment, the insertion tube may be extruded or otherwise formed over the assembly, eliminating the need for a draw wire.

[0031] At 1040, the inserts are attached to the insertion tubes. This attachment is optional and if the inserts are sufficiently held in place by resilient pressure from the walls of the insertion tube or by forming the insertion tube on the assembly, further attachment may be unnecessary. As mentioned above, if attachment is required, heat staking, RF welding, or other attachment techniques may be used. In some embodiments, the insertion tubes may be a heat shrink material to facilitate placement of the assembly within the insertion tube, and heat is then applied to attach the insertion tube to each insert.

[0032] At 1045, a transducer cable is attached at each end to couple the transducer to the handle, and at 1050, an articulation pull cable is attached at each end of the assembly to couple the flexible distal ends to articulation controls in the handle.

[0033] Final assembly of the catheter is performed at 1055 by joining the insertion tube to the handle and flexible distal end.

[0034] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive, and the invention is not limited to the disclosed embodiments.

[0035] For example, it is possible to operate the invention in an embodiment where a continuous insert is co-extruded over the transducer cable and then selectively etched or otherwise reduced in diameter to create multiple full-sized (unetched) inserts between these thinner (etched) segments. For example, material between the pull cable lumens 460 along the periphery of the continuously extruded insert can be selectively removed, leaving only the transducer cable embedded in the remaining material between the inserts unaltered.

[0036] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Reference signs in the claims, if any, shall not be interpreted as limiting the scope of the claims.

Claims

1. a handle having a steering element; a flexible distal end; an insertion tube disposed between the handle and the distal end; at least one transducer cable coupling the handle to a transducer via the insertion tube; a plurality of articulated pull cables connecting the steering element to the distal end via the insertion tube; 1. An elongate medical device having: the distal end having the transducer; the plurality of articulated pull cables are controlled at the steering element to articulate the distal end in a desired direction; the insertion tube includes a plurality of inserts having a constant cross-sectional shape along its length; the plurality of inserts are spaced apart along the insertion tube from the handle to the distal end and are attached to the insertion tube; each insert of the plurality of inserts includes a plurality of lumens; The plurality of lumens include one or more transducer cable lumens through which the at least one transducer cable passes; a plurality of pull cable lumens through which the plurality of articulation pull cables extend; having the plurality of lumens separating the transducer cable and each of the plurality of articulation pull cables from one another; each of the one or more transducer cable lumens is located in a central region of the insert; each of the plurality of pull cable lumens has a C-shaped lumen located along a peripheral region of the insert; Device.

2. The device of claim 1 , wherein the flexibility of the flexible distal end is substantially greater than the flexibility of the insertion tube.

3. The device of claim 1 or 2, wherein the opening of the C-shaped lumen is smaller than the diameter of the articulation pull cable.

4. The apparatus of claim 1 , wherein the one or more transducer cable lumens are closed and fixedly attached to the one or more transducer cables.

5. each of the pull cable lumens is sized to allow a respective joint pull cable to move freely therethrough; and / or each of the plurality of pull cable lumens includes a lubricious material that facilitates movement of the joint pull cable through the pull cable lumen; 5. Apparatus according to any one of claims 1 to 4.

6. 6. An apparatus according to any preceding claim, wherein each insert comprises a high temperature resilient material.

7. 7. The device of claim 1, wherein each insert is fixed to the insertion tube.

8. The apparatus of claim 1 , wherein the at least one transducer cable, the plurality of articulated pull cables, and the plurality of inserts are configured as a string of components that is inserted into the insertion tube.

9. 9. The apparatus of claim 1, further comprising a draw wire fixedly attached to each of the inserts, the draw wire enabling the inserts to be drawn into the insertion tube.

10. a plurality of inserters configured to be inserted into and attached to an insertion tube of an elongated medical device; one or more transducer cables traversing each of the plurality of inserts; a draw wire fixedly attached to the plurality of inserts; In an assembly of a component having each of the plurality of inserts has a constant cross-sectional shape along its length; one or more transducer cable lumens located in a central region of the insert; and a plurality of pull cable lumens, each having a C-shaped lumen located along a peripheral region of the insert allowing a plurality of articulated pull cables to move freely through the insert; Including, assembly.

11. Each insert has a resilient material; Each pull cable lumen is C-shaped; Each pull cable lumen has a C-shaped opening, the opening being narrower than the diameter of the articulation pull cable.

11. A lumen assembly according to claim 10.

12. 12. An assembly according to any of claims 10 to 11, wherein each of the one or more transducer cables is fixedly attached to a respective insert.

13. 1. A method of assembling an elongate medical device, comprising: Providing a handle, an insertion tube, a flexible distal tip, and a transducer; Creating an assembly of a component having a plurality of inserts, one or more transducer cables traversing each of the plurality of inserts, and draw wires fixedly attached to the plurality of inserts, comprising: each of the plurality of inserts having a constant cross-sectional shape along its length; one or more transducer cable lumens located in a central region of the insert; and a plurality of pull cable lumens, each having a C-shaped lumen located along a peripheral region of the insert allowing a plurality of articulated pull cables to move freely through the insert; and passing the plurality of articulation pull cables through the plurality of pull cable lumens in each of the plurality of inserts; passing the draw wire through the insertion tube; pulling the draw wire to move the assembly of components into the insertion tube; attaching the plurality of articulation pull cables to an articulation control at the handle and to a terminator at the flexible distal end; coupling the one or more transducer cables to the handle and to the transducer at a distal end of the flexible distal tip; coupling the insertion tube to the handle and to the flexible distal end; attaching the plurality of inserts to the insertion tube; The method according to claim 1,

14. 14. The method of claim 13, wherein the insert is elastic and each pull cable lumen is C-shaped with an opening narrower than a diameter of the joint pull cable, the method including pushing the joint pull cable through the opening using the elasticity of the insert to expand the opening.

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