Medical device shaft with reduced agitation

Abstract

The present invention is entitled "Medical Device Shaft with Reduced Agitation". The present invention provides a medical probe, which includes a flexible insertion tube, the flexible insertion tube having a proximal section and a deflectable distal section, and accommodating a first lumen and a second lumen extending longitudinally through the insertion tube, wherein the first lumen and the second lumen are intertwined with each other in the proximal section and extend parallel to each other in the deflectable distal section. The medical probe also includes a first wire and a second wire, the first wire and the second wire extending through the first lumen and the second lumen, respectively, and having corresponding first and second distal ends, which are anchored in the deflectable distal section of the insertion tube.

Description

Technical Field

[0001] The present invention relates generally to invasive probes, and in particular to medical probes having a deflectable distal section. Background Art

[0002] Some medical procedures, such as mapping the cavity of a body organ (e.g., the heart), are performed by inserting a medical probe into the cavity. In some configurations, the medical probe includes a distal segment that can be deflected along a plane. Deflection (i.e., together with extension, retraction, and rotation of the medical probe) enables the distal tip of the deflectable distal segment to engage tissue at different locations in the body cavity.

[0003] In additional configurations, the medical probe can deliver radiofrequency (RF) current to ablate tissue in contact with the distal end of the probe to provide a therapeutic result. In alternative configurations, the medical probe can deliver a different energy source, such as laser, ultrasound or cryogenic cooling to provide a therapeutic result.

[0004] U.S. Patent Application 2010 / 0057050 to Webler describes a catheter configured for incremental rotation. The catheter includes a shaft having a distal segment that includes an incremental rotation inducing feature that minimizes agitation of the shaft as the shaft rotates. Examples of incremental rotation inducing features include two or more longitudinal shaft portions having a lower flexural modulus spaced circumferentially around the shaft.

[0005] U.S. Patent Application 2005 / 0070844 to Chow et al. describes a deflectable catheter. The catheter includes a shaft having a proximal segment and a distal segment that is more flexible than the proximal segment. The catheter also includes a needle assembly and a tendon disposed in a lumen that is approximately centered within the shaft at the proximal segment and eccentric to the shaft at the distal segment. In some embodiments, the tendon and the needle assembly are wound around each other.

[0006] U.S. Patent Application 2002 / 0165461 to Hayzelden et al. describes a steerable catheter having a shaft support system for resisting axial compressive loads. The catheter has a relatively flexible distal end region and includes a torque transfer system to enhance torque transfer from the handle to the distal tip. The torque transfer system includes a flat band within the relatively flexible distal end region to enhance torque transfer through the distal end region of the catheter.

[0007] U.S. Patent 6,183,463 to Webster describes a bidirectionally steerable catheter having a bidirectional control handle. The catheter includes a thermocouple formed from a wire pair. The wires of the wire pair are electrically isolated from each other (except at their distal ends), twisted together, and covered with a short piece of plastic tubing and covered with epoxy.

[0008] U.S. Patent Application 2006 / 0184106 to McDaniel et al. describes a steerable catheter with in-plane deflection. The catheter has a terminal segment at the distal end of the catheter body, the terminal segment comprising a flexible plastic tube having a pair of diametrically opposed lumens. The catheter also includes two puller wires, each of which extends through one of the pair of lumens in the terminal segment and through the catheter body, is anchored to a control handle at its proximal end, and is anchored to the terminal segment at its distal end.

[0009] Documents incorporated by reference into this patent application are considered to be an integral part of this application, except that if any terms defined in these incorporated documents conflict with definitions explicitly or implicitly given in this specification, only the definitions in this specification shall prevail.

[0010] The above description gives a general overview of the relevant technology in the field and should not be construed as an admission that any information it contains constitutes prior art against the present patent application. Summary of the invention

[0011] According to an embodiment of the present invention, a medical probe is provided, which includes: a flexible insertion tube, the flexible insertion tube having a proximal section and a deflectable distal section, and accommodating a first lumen and a second lumen extending longitudinally through the insertion tube, wherein the first lumen and the second lumen are wound around each other in the proximal section and extend parallel to each other in the deflectable distal section; and a first wire and a second wire, the first wire and the second wire respectively extending through the first lumen and the second lumen, and having corresponding first distal ends and second distal ends, the first distal ends and the second distal ends anchored in the deflectable distal section of the insertion tube.

[0012] In one embodiment, the medical probe further comprises a first compression coil and a second compression coil, wherein the first compression coil and the second compression coil respectively accommodate the first wire and the second wire and respectively comprise the first lumen and the second lumen. In an additional embodiment, the medical probe further comprises a first tubular structure and a second tubular structure respectively accommodating the first compression coil and the second compression coil.

[0013] In another embodiment, the medical probe further comprises a third lumen extending longitudinally through the insertion tube, wherein the first lumen, the second lumen and the third lumen are wound around each other in the proximal section. In a supplementary embodiment, the medical probe further comprises one or more functional elements extending through the third lumen, wherein a given functional element is selected from a list consisting of additional wires, cables and flushing lines.

[0014] In some embodiments, a pull on each of the wires deflects the deflectable distal segment in different respective directions. In one embodiment, the first lumen and the second lumen that are entangled with each other in the proximal segment limit agitation of the probe as it rotates. In another embodiment, the first wire and the second wire include respective first and second proximal ends, and the medical probe further includes a handle coupled to the first and second proximal ends to control the pull on the wires. In additional embodiments, the deflection is in a two-dimensional plane.

[0015] In further embodiments, the first end and the second end of the wire are each anchored at different respective points within the deflectable distal section of the insertion tube.

[0016] According to an embodiment of the present invention, a method for manufacturing a medical probe is also provided, the method comprising: providing a flexible insertion tube, the flexible insertion tube having a proximal section and a deflectable distal section, and accommodating a first lumen and a second lumen extending longitudinally through the insertion tube, wherein the first lumen and the second lumen are wound around each other in the proximal section and extend parallel to each other in the deflectable distal section; and extending a first wire and a second wire through the first lumen and the second lumen, respectively, the first wire and the second wire having corresponding first distal ends and second distal ends, the first distal ends and the second distal ends being anchored in the deflectable distal section of the insertion tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present disclosure is herein described, by way of example only, with reference to the accompanying drawings, in which:

[0018] Figure 1 is a schematic diagram of a medical system according to an embodiment of the present invention, the medical system comprising a medical probe having a deflectable distal section;

[0019] Figure 2 is a schematic longitudinal sectional view of a medical probe according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of a deflectable segment inside a heart chamber according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] Embodiments of the present invention describe a medical probe with a flexible insertion tube, which includes a proximal section and a deflectable distal section. The medical probe includes a first lumen and a second lumen extending longitudinally through the insertion tube, wherein the first lumen and the second lumen are wound around each other in the proximal section and extend parallel to each other in the deflectable distal section. On the proximal side, the lumen is formed by a hollow coil surrounded by a polymer tube. These coils, which are called "compression coils", are fixed in a compressed manner so that the coils are pressed downward, thereby allowing the compression coils to have high axial strength, but with much greater flexibility than a metal tube. The medical probe also includes a first wire and a second wire extending through the first lumen and the second lumen, respectively, the wire having a corresponding first distal end and a second distal end, which can be anchored at different corresponding points in the deflectable distal section of the insertion tube.

[0022] During medical procedures, the proximal segment may be bent by a sheath or anatomical structure. If the compression coil extends in parallel along the length of the proximal segment, the proximal segment may have a stiffness related to rotation. Due to this stiffness, when the proximal segment of the probe is twisted (i.e., rotated) by a medical professional, agitation (i.e., an undesirable rotational motion of the distal segment) may occur. This may cause the probe to be difficult to reach certain positions of the anatomical structure and to remain stable at certain positions of the anatomical structure, and due to undesired catheter movement, especially during the delivery of treatment, potential safety issues may exist. In the medical probe implementing an embodiment of the present invention, the compression coils are wound around each other in the proximal segment. Therefore, the proximal segment of the probe is rotationally symmetrical and does not have a preferred bending direction. Therefore, the distal segment of the medical probe implementing an embodiment of the present invention generally has minimal agitation when twisted by a medical professional.

[0023] System Description

[0024] Figure 1 2 is a schematic illustration of a medical system 20 including a medical probe 22 and a console 24 according to an embodiment of the present invention. The medical system 20 may be based on, for example, a medical probe 22 manufactured by Biosense Webster Inc. (33 Technology Drive, Irvine, CA 92618 USA). In the embodiments described below, the medical probe 22 may be used for diagnostic or therapeutic treatments, such as for mapping electrical potentials in a heart 26 of a patient 28. Alternatively, the medical probe 22 may be used mutatis mutandis for other therapeutic and / or diagnostic purposes in the heart or other body organs.

[0025] Probe 22 includes an insertion tube 30 and a handle 32 coupled to the proximal end of the insertion tube. By manipulating handle 32, a medical professional 34 can insert probe 22 into a body cavity of a patient 28. For example, a medical professional 34 can insert probe 22 through the vascular system of patient 28 such that a distal end 36 of probe 22 enters a chamber of heart 26 and engages endocardial tissue at a desired location or locations.

[0026] The console 24 is connected to body surface electrodes, which typically include an adhesive skin patch 40 attached to the patient 28, via cables 38. The console 24 includes a processor 42 that, in conjunction with a current tracking module 44, determines the position coordinates of the distal end 36 inside the heart 26 based on the impedance and / or current measured between the adhesive skin patch 40 and the electrodes 46 attached to the distal end 36. In addition to being used as position sensors during medical procedures, the electrodes 46 may also perform other tasks, such as measuring the electrical activity of the heart 26.

[0027] As described above, in conjunction with the current tracking module 44, the processor 42 can determine the position coordinates of the distal end 36 inside the heart 26 based on the impedance and / or current measured between the adhesive skin patch 40 and the electrode 46. This determination is typically after a calibration process has been performed to relate the impedance or current to the known position of the distal end. In some embodiments, the electrode 46 can be configured to apply a signal to tissue in the heart 26 and / or measure a certain physiological property (e.g., a local surface potential) at a certain location in the heart.

[0028] Processor 42 may include real-time noise reduction circuitry 48, typically configured as a field programmable gate array (FPGA), followed by an analog-to-digital (A / D) signal conversion integrated circuit 50. The processor may pass signals from the A / D circuitry 50 to another processor and / or may be programmed to determine the position coordinates mentioned above.

[0029] although Figure 1 The illustrated medical system uses impedance or current based sensing to measure the position of the distal end 36, but other position tracking techniques (e.g., techniques using magnetic based sensors) may be used. Impedance and current based position tracking techniques are described in, for example, U.S. Patents 5,983,126, 6,456,864, and 5,944,022. The position sensing methods described above are described in the above The invention is implemented in the system and is described in detail in the patent cited above.

[0030] The console 24 also includes an input / output (I / O) communication interface 51 that enables the console to transmit signals from the electrode 46 and the adhesive skin patch 40 and / or transmit signals to the electrode and the adhesive skin patch. Based on the signals received from the electrode 46 and the adhesive skin patch 40, the processor 42 can generate a map 52 showing the position of the distal end 36 in the patient's body. During surgery, the processor 42 can present the map 52 to the medical professional 34 on the display 54, and store the data representing the map in the memory 56. The memory 56 may include any suitable volatile memory and / or non-volatile memory, such as a random access memory or a hard drive. In some embodiments, the medical professional 34 can manipulate the map 52 using one or more input devices 58. In an alternative embodiment, the display 54 may include a touch screen that may be configured to accept input from the medical professional 34 in addition to presenting the map 52.

[0031] Figure 2 1 is a schematic longitudinal cross-sectional view of a probe 22 according to an embodiment of the present invention. The insertion tube 30 includes a proximal section 60 and a deflectable distal section 62, both of which are covered by a biocompatible flexible material 64. The distal section 62 includes a proximal end 104.

[0032] The insertion tube 30 includes a pair of tubular structures (also referred to herein as tubes) 66 and 68 extending longitudinally within the insertion tube 30 and including corresponding lumens 70 and 72. Lumens 70 and 72 (i.e., tubes 66 and 68) are wound around each other within the proximal section 60 and extend parallel to each other within the deflectable distal section 62. In some embodiments, the distal section 62 can be formed by an extrusion process, and the lumen can be formed as a separate tube larger than the proximal tube during extrusion. During assembly, the proximal tube of smaller diameter can be bonded within the distal tube of larger diameter, thereby producing a discontinuous lumen. In an embodiment of the present invention, the term parallel to each other means that the lumens are parallel within a predetermined tolerance, and the predetermined tolerance is, for example, 10 degrees, 5 degrees, or 2 degrees.

[0033] The probe 22 also includes a pair of compression coils 74 and 76 having respective distal ends 106 and 108 and housed in tubes 66 and 68, respectively. In one embodiment, the compression coils 74 and 76 are fixed to the proximal ends 110 and 112 of the lumen in the segment 62, respectively, with a bonding material such as a polyurethane adhesive or epoxy resin (not shown). Between these fixed positions and the distal ends 106 and 108, each of the compression coils can be shaped to not be pressed down. This allows any unfixed segment of the compression coil in the distal segment 62 to be compressed during deflection and not prevent movement. Alternatively, the compression coils 74 and 76 can terminate at proximal fixed positions (e.g., positions 110 and / or positions 112), and a low-friction flexible tube (not shown) can be placed above the puller wire. In this embodiment, the length of the flexible tube can be selected to be 1mm-5mm shorter than the distance between the fixed positions 110 and 112 and the distal positions 106 and 108, thereby ensuring that the flexible tube does not prevent the desired deflection. Stylet 22 also includes a pair of puller wires 78 and 80 housed within coils 74 and 76 , respectively, and having respective proximal ends 82 and 84 and respective distal ends 86 and 88 .

[0034] In one embodiment, distal ends 86 and 88 are anchored to points 90 and 92, respectively, in distal segment 62 of probe 22. In another embodiment, distal ends 86 and 88 may each be anchored to a single point (eg, point 90 or 92) in distal segment 62 of probe 22.

[0035] In an alternative embodiment, the insertion tube 30 can be configured to implement embodiments of the present invention without tubes 66 and 68. In this alternative embodiment, the compression coils are wrapped around each other in the proximal section 60 and enter the proximal end 104 of the distal section 62.

[0036] exist Figure 2 In the illustrated configuration, proximal ends 82 and 84 are each coupled to a deflection knob 94 in handle 32. As described below, medical professional 34 may manipulate knob 94 to control deflection of distal segment 62 in a two-dimensional plane 96 corresponding to the plane of the paper.

[0037] exist Figure 2In the illustrated configuration, the handle 32 includes a housing 114 that houses two rack gear channels 116. Preferably, the rack gear channels 116 are located in opposite quadrants within the housing 114. A rack gear 118 is slidably mounted within each rack gear channel 116. Each rack gear 118 is generally rectangular and has teeth 120 along the length of its interior edge. Between the rack gears 118 is a spur gear 122 that also has teeth 124. The teeth 124 of the spur gear 122 receive the teeth 120 of the rack gears 118 so that proximal movement of one of the rack gears causes distal movement of the other rack gear.

[0038] The proximal ends 82 and 84 of the pull wires 78 and 80 are attached to the distal ends of the rack gear 118 respectively by the pull wire coupling 126. The coupling 126 can be integral with the rack gear 118 or fixedly attached to the rack gear. Each rack gear 118 can be welded or glued to the coupling 126, for example, with polyurethane or epoxy resin. Alternatively, the proximal end of each pull wire coupling 126 can include a threaded hole to receive a threaded column at the distal end of the corresponding rack gear 118. The coupling 126 can be made of any suitable material, such as aluminum, brass or stainless steel.

[0039] The deflection knob 94 extends around the circumference of the handle housing 114, thereby allowing the medical professional 34 to manipulate the knob regardless of how the handle 32 is rotated. If the deflection knob 94 is moved proximally, the corresponding rack gear 118 moves in the proximal direction, which causes the attached puller wire to be pulled proximally. This causes the distal segment 62 to deflect in the direction of the quadrant of the lumen in the distal segment through which the puller wire extends.

[0040] On the contrary, if the deflection knob 94 is pushed toward the distal side, the corresponding rack gear 118 moves toward the distal side. Therefore, the opposite rack gear 118 moves toward the proximal side, pulling the corresponding puller wire and deflecting the distal section 62 in the opposite direction.

[0041] exist Figure 2 In the illustrated configuration, the electrode 46 is attached to the distal tip 98 of the distal segment 62. The electrode 46 is connected to the console 24 by a wire (not shown) that extends through an additional lumen (not shown) in the insertion tube 30. As described above, the system 20 can use the electrode 46 to perform tasks such as determining the position of the distal end 36 and measuring the electrical activity of the heart 26. In some embodiments, the tubes 66, 68 and their respective lumens can accommodate additional tubular structures of one or more functional elements (e.g., additional wires, cables, and irrigation lines) that can be wrapped around each other within the proximal segment 60.

[0042] Figure 3Detailed schematic view of the distal segment 62 in the chamber 130 of the heart 26 according to an embodiment of the present invention. When the distal tip is positioned to engage any intracardiac tissue 132 in the chamber 130, the medical professional 34 can rotate the handle 32 to rotate the insertion tube 30, and can manipulate the knob 94 to deflect (i.e., bend) the distal segment 62. As described above, the proximal segment 60 is rotationally symmetric because the proximal segment includes the wire 78 and the compression coil 74 wrapped around the wire 80 and the compression coil 76. Therefore, even when bent, the distal segment generally has minimal agitation when the operator rotates the handle 32.

[0043] In some configurations, the twists per inch (TPI) of coils 74 and 76 may be in the range of 0.5-2.0 twists per inch. During a medical procedure, the bend that the proximal segment 62 needs to traverse is typically relatively gentle compared to the bend in the deflectable segment 60. For example, in some medical procedures, the probe 22 traverses the inferior vena cava. To gain transseptal access to the left atrium, the probe needs to make a 90 degree turn. If the medical professional then wishes to enter the left ventricle with the probe 22, this may require an additional 90 degree turn.

[0044] The "tight" bend radius of the proximal segment 60 may be about one inch. In this case, a 90 degree turn (i.e., a quarter circle) requires a path length of about 1.6 inches. At the lowest torsion of the puller wire and compression coil (i.e., 0.5 TPI), there will still be more than half of the torsion cycle in the 90 degree turn. Therefore, on one portion of the turn, the puller wire will be biased to preferentially bend in that direction, and on another portion of the turn, the puller wire will be biased to preferentially bend in the opposite direction.

[0045] It should be understood that the above embodiments are cited by way of example, and the present invention is not limited to what is specifically shown and described above. On the contrary, the scope of the present invention includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which should occur to those skilled in the art when reading the above description, and which are not disclosed in the prior art.

Claims

1. A medical probe, comprising: a flexible insertion tube comprising a proximal section and a deflectable distal section and housing a first lumen and a second lumen extending longitudinally through the insertion tube, wherein the first lumen and the second lumen are intertwined with each other only in the proximal section and extend parallel to each other in the deflectable distal section; and A first wire and a second wire, the first wire and the second wire extend through the first lumen and the second lumen respectively and include corresponding first and second distal ends, the first and second distal ends are anchored within the deflectable distal section of the insertion tube.

2. The medical probe of claim 1, and comprising first and second compression coils, the first and second compression coils accommodating the first and second wires, respectively, and comprising the first and second lumens, respectively.

3. The medical probe according to claim 2, wherein the medical probe comprises a first tubular structure and a second tubular structure, wherein the first tubular structure comprises the first lumen and the second tubular structure comprises the second lumen, wherein the first compression coil is accommodated in the first lumen and the second compression coil is accommodated in the second lumen.

4. The medical probe of claim 1, and comprising a third lumen extending longitudinally through the insertion tube, wherein the first lumen, the second lumen, and the third lumen are intertwined with one another in the proximal section.

5. The medical probe of claim 4, and comprising one or more functional elements extending through the third lumen, wherein a given functional element is selected from the list consisting of an additional wire, a cable, and an irrigation line.

6. The medical probe of claim 1, wherein pulling on each of the first and second wires deflects the deflectable distal segment in different respective directions.

7. The medical probe of claim 6, wherein the first lumen and the second lumen being intertwined with each other in the proximal section restrict agitation of the probe as it is rotated.

8. The medical probe of claim 6, wherein the first and second wires include respective first and second proximal ends, and the medical probe further includes a handle coupled to the first and second proximal ends for controlling the pulling on the first and second wires.

9. The medical probe of claim 6, wherein the deflection is in a two-dimensional plane.

10. The medical probe of claim 1, wherein the first distal end of the first wire and the second distal end of the second wire are respectively anchored at different corresponding points within the deflectable distal section of the insertion tube.

11. A method for manufacturing a medical probe, comprising: providing a flexible insertion tube comprising a proximal section and a deflectable distal section and housing a first lumen and a second lumen extending longitudinally through the insertion tube, wherein the first lumen and the second lumen are wound around each other only in the proximal section and extend parallel to each other in the deflectable distal section; as well as A first wire and a second wire are extended through the first lumen and the second lumen, respectively, the first wire and the second wire having respective first and second distal ends anchored within the deflectable distal section of the insertion tube.

12. The method of claim 11, and comprising providing first and second compression coils accommodating the first and second wires, respectively, and comprising the first and second lumens, respectively.

13. The method of claim 12, wherein the medical probe comprises a first tubular structure and a second tubular structure, wherein the first tubular structure comprises the first lumen and the second tubular structure comprises the second lumen, wherein the first compression coil is accommodated in the first lumen and the second compression coil is accommodated in the second lumen.

14. The method of claim 11, and comprising extending a third lumen longitudinally through the insertion tube, wherein the first lumen, the second lumen, and the third lumen are intertwined with one another in the proximal segment.

15. The method of claim 14, and comprising extending one or more functional elements through the third lumen, wherein a given functional element is selected from the list consisting of an additional wire, a cable, and an irrigation line.

16. The method of claim 11, wherein pulling on each of the first wire and the second wire deflects the deflectable distal segment in different respective directions.

17. The method of claim 16, wherein the first lumen and the second lumen being intertwined with each other in the proximal section limit agitation of the probe as it is rotated.

18. The method of claim 16, wherein the first and second wires include respective first and second proximal ends, and the medical probe further includes a handle coupled to the first and second proximal ends for controlling the pulling on the first and second wires.

19. The method of claim 16, wherein the deflection is in a two-dimensional plane.

20. The method of claim 11, and comprising anchoring the first distal end of the first wire and the second distal end of the second wire at different respective points within the deflectable distal section of the insertion tube, respectively.

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