Collapsible flat catheter

Abstract

To provide a cardiac mapping and / or ablation catheter having a flexible probe tip.SOLUTION: A medical probe including an end effector is disclosed herein. The end effector includes a flexible insulative material extending along a plane, a framework disposed within the flexible insulative material, and a flexible circuit disposed within the flexible insulative material and spaced apart from the framework. The flexible circuit includes a central branch segment, a plurality of outer branch segments, and a plurality of electrodes. The central branch segment extends along a longitudinal axis of the plane. The outer branch segments extend along a plane at a distance away from the longitudinal axis, and at least some of the outer branch segments extend distally of the central branch segment, thereby defining a recess at the distal end of the end effector. The electrodes are disposed along the central branch and the plurality of outer branch segments.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of priority to earlier U.S. Provisional Patent Application No. 63 / 669,318, filed July 10, 2024 (Attorney Docket No. BIO6934USPSP1-253757.000495), the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE INVENTION The present disclosure relates generally to minimally invasive medical devices, and more particularly to cardiac mapping and / or ablation catheters having flexible probe tips. [Background technology]

[0003] Cardiac arrhythmias, such as atrial fibrillation, occur when electrical signals are abnormally conducted from an area of ​​cardiac tissue to adjacent tissue, disrupting the normal cardiac cycle and causing an asynchronous rhythm. The source of the unwanted signals may be located in the atrial or ventricular tissue. The unwanted signals may be conducted through the cardiac tissue to other locations and cause or perpetuate the arrhythmia.

[0004] Treatments for arrhythmias include surgically disrupting the source of the signals that cause the arrhythmia and interrupting the conduction pathways of such signals. More recently, it has been discovered that by mapping the electrical properties and volume of the endocardium and selectively ablating cardiac tissue through the application of energy, it is possible to interrupt or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process disrupts the unwanted electrical pathways through the creation of non-conductive lesions.

[0005] In this two-step procedure, which involves mapping followed by ablation, electrical activity at points within the heart is sensed and measured, typically by advancing a catheter equipped with one or more electrical sensors into the heart and acquiring data at multiple points, which are then used to select a target area where ablation will be performed.

[0006] For higher mapping resolution, it is desirable for a mapping catheter to closely conform to the target anatomical structure. For mapping within the atria or ventricles (e.g., the apex of the ventricles), it is desirable for the catheter to collect more data signals in a short period of time. It is also desirable for such a catheter to enable sufficient electrode contact with various tissue surfaces, e.g., flat, curved, irregular, or non-planar surface tissue, and be foldable for non-invasive advancement and retraction through the patient's vascular system. Existing catheters generally require rigid internal structural members to ensure that a predetermined configuration is maintained. Rigidity is a disadvantage during manipulation within a body organ because it can prevent electrodes from contacting tissue.

[0007] Other catheters may include flexible probe tips designed to overcome this disadvantage. These catheters may include layered components that can be time-consuming, complex, and expensive to manufacture and assemble. Furthermore, the electrical traces and other associated components may be prone to breakage and / or delamination during use. Summary of the Invention [Means for solving the problem]

[0008] An end effector is provided according to the disclosed technology. The end effector includes a flexible insulating material extending along a plane, a framework disposed within the flexible insulating material, and a flexible circuit disposed within the flexible insulating material and spaced from the framework. The flexible circuit includes a central branch segment, a plurality of outer branch segments, and a plurality of electrodes. The central branch segment extends along a longitudinal axis of the plane. The outer branch segments extend along the plane a distance away from the longitudinal axis, and at least some of the outer branch segments extend distally of the central branch segment, thereby defining a recess at a distal end of the end effector proximate the longitudinal axis. Electrodes are disposed along the central branch and the plurality of outer branch segments.

[0009] According to the disclosed technology, an end effector is provided, the end effector including: a flexible insulating material extending along a plane; a framework disposed within the flexible insulating material; a first flexible circuit disposed within the flexible insulating material and spaced apart from the framework on one side of the framework; and a second flexible circuit disposed within the flexible insulating material and spaced apart from both the framework and the first flexible circuit. Each of the first flexible circuit and the second flexible circuit includes a central branch segment extending along a longitudinal axis of the plane, a first set of electrodes disposed on the central branch segment, a plurality of outer branch segments extending along the plane a distance away from the longitudinal axis, and a second set of electrodes disposed along adjacent outer branch segments, the first set of electrodes and the second set of electrodes being misaligned with each other in a direction transverse to the longitudinal axis.

[0010] In accordance with the disclosed techniques, a method of manufacturing an end effector for a medical probe is provided, the method including forming electrodes on a flexible circuit, coating the electrodes with an impedance-reducing coating, and coating the electrodes with a hydrophilic coating.

[0011] In accordance with the techniques of the present disclosure, a method for manufacturing a flexible circuit for a medical catheter is provided, the method including forming a substrate extending along a plane, disposing a conductive material along the substrate, and cutting the conductive material and substrate along a curve in the flexible substrate such that the flexible substrate and the conductive material form a plurality of individual branches. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram of a medical system including a planar medical probe in accordance with the techniques of the present disclosure. [Figure 2A] FIG. 1 is a schematic pictorial representation of a front view of a probe tip in accordance with the techniques of the present disclosure. [Figure 2B] FIG. 10 is a schematic pictorial diagram showing a plan view of another probe tip in accordance with the techniques of the present disclosure. [Figure 3] 2B is a schematic pictorial diagram showing an exploded perspective view of the probe tip of FIG. 2A. FIG. [Figure 4] FIG. 1 is a schematic pictorial representation of a front view of a probe tip in accordance with the techniques of the present disclosure. [Figure 5A] 1 is a schematic pictorial diagram showing a probe tip retracted into a sheath in an ideal case, in accordance with the techniques of the present disclosure; [Figure 5B] 1 is a schematic, pictorial diagram showing a probe tip retracted into a sheath in an exemplary case where excess material is present, in accordance with the disclosed technique; [Figure 6A] FIG. 1 is a schematic pictorial diagram showing a top view of another probe tip, with portions thereof removed for clarity, in accordance with the techniques of the present disclosure. [Figure 6B] FIG. 1 is a schematic pictorial diagram showing a top view of a position sensor in accordance with the techniques of the present disclosure. [Figure 7A] FIG. 1 is a schematic pictorial diagram showing a top view of a distal portion of a probe tip in accordance with the techniques of the present disclosure. [Figure 7B] 1 is a schematic depiction of a detailed view of a typical flexible circuit at the tip of a probe, including a detailed cross-section of a portion thereof; [Figure 7C]1 is a schematic depiction of a detailed view of a portion of a flexible circuit at a probe tip, including a detailed cross-sectional view of the portion, in accordance with the disclosed technique; [Figure 7D] FIG. 10 is a schematic pictorial diagram showing a detailed view of another flexible circuit at the probe tip, in accordance with the techniques of the present disclosure. [Figure 7E] FIG. 10 is a schematic pictorial diagram showing a detailed view of another flexible circuit at the probe tip, in accordance with the techniques of the present disclosure. [Figure 8] FIG. 1 is a flow diagram of a method for making a flexible circuit having one or more strain relief loops in accordance with the techniques of the present disclosure. [Figure 9A] FIG. 1 is a schematic, pictorial diagram showing a detailed view of an electrode provided with an impedance-reducing coating in accordance with the disclosed technique. [Figure 9B] FIG. 1 is a schematic pictorial diagram showing a detailed view of a coated electrode in accordance with the disclosed technique. [Figure 10] FIG. 10 is a schematic diagram of a graph of resistance over a range of frequencies when lubricant is used and when no lubricant is used, in accordance with the techniques of the present disclosure. [Figure 11A] FIG. 1 is a schematic, pictorial diagram showing a multivariate chart for peak-to-peak data for coated and uncoated electrodes in accordance with the disclosed technique. [Figure 11B] FIG. 1 is a schematic, pictorial diagram showing a multivariate chart of impedance at 10 Hz for coated and uncoated electrodes in accordance with the disclosed technique. [Figure 12] FIG. 1 is a flow diagram of a method for fabricating a flexible circuit with coated electrodes in accordance with the techniques of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered the same. 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, but not by way of limitation, the principles of the invention. This description will clearly enable any person skilled in the art to make and use the invention and sets forth several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently contemplated to be the best mode for carrying out the invention.

[0014] As used herein, the terms "about," "approximately," or "generally" in connection with any numerical value or range indicate a suitable dimensional tolerance that enables a portion or collection of components to function for the intended purpose described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±20% of the recited value, while, for example, "about 90%" may refer to a range of values ​​of 71% to 110%. Additionally, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject, and while use of the subject technology in human patients represents a preferred embodiment, it is not intended to limit the systems or methods to human use. Similarly, the term "proximal" refers to a location closer to the operator or physician, while "distal" refers to a location farther from the operator or physician.

[0015] As discussed herein, the vascular system of a "patient," "host," "user," and "subject" may be that of a human or any animal. It should be understood that the animal may be of any of a variety of applicable types, including, but not limited to, mammals, veterinary animals, livestock animals, or companion animals. As an example, the animal may be a laboratory animal (e.g., rat, dog, pig, monkey, etc.) specifically selected to have certain characteristics similar to humans. It should be understood that the subject may be, for example, any applicable human patient.

[0016] As discussed herein, an "operator" may include a physician, surgeon, technician, scientist, or any other individual or delivery instrument associated with the delivery of a multi-electrode catheter for the treatment of drug-refractory atrial fibrillation to a subject.

[0017] The present disclosure relates to systems, methods, uses, and devices for mapping and ablation of cardiac tissue to treat cardiac arrhythmias. Ablation energy is typically delivered to cardiac tissue by a distal portion of a catheter capable of delivering the ablation energy along the tissue to be ablated. Some exemplary catheters include a three-dimensional structure at the distal portion and are configured to administer the ablation energy from various electrodes positioned on the three-dimensional structure. Ablation procedures incorporating such exemplary catheters can be visualized using fluoroscopy.

[0018] Ablation of cardiac tissue using radiofrequency (RF) energy and thermal techniques, such as cryoablation, to improve cardiac function is a well-known procedure. Successful ablation using thermal techniques typically requires measuring cardiac potentials at various locations in the myocardium. Additionally, temperature measurements during ablation provide data that enables assessment of ablation effectiveness. Typically, ablation procedures using thermal techniques involve measuring electrode potentials and temperatures before, during, and after the actual ablation. RF approaches can pose risks that can lead to tissue charring, burning, steam popping, phrenic nerve paralysis, pulmonary vein stenosis, and esophageal fistulas. Cryoablation is an alternative approach to RF ablation that can reduce some of the thermal risks associated with RF ablation. However, operating a cryoablation device and selectively applying cryoablation are generally more difficult than RF ablation. Therefore, cryoablation is not feasible in certain anatomical shapes that can be reached by electrical ablation devices.

[0019] The present disclosure may include electrodes configured for RF ablation, cryoablation, and / or irreversible electroporation (IRE). IRE may be referred to interchangeably throughout this disclosure as pulsed electric field (PEF) ablation and pulsed field ablation (PFA). IRE, as discussed in this disclosure, is a non-thermal cell death technique that can be used to ablate atrial arrhythmias. To ablate using IRE / PEF, biphasic voltage pulses are applied to destroy myocardial cellular structures. The biphasic pulses are non-sinusoidal waveforms that can be tailored to target cells based on the electrophysiology of the cells. In contrast, to ablate using RF, a sinusoidal voltage waveform is applied to generate heat in the treatment area, indiscriminately heating all cells within the treatment area. Therefore, IRE has the ability to spare adjacent heat-sensitive structures or tissues, which may be beneficial in reducing potential complications known with ablation or isolation modalities. Additionally or alternatively, monophasic pulses may be utilized.

[0020] Reference is made to FIG. 1 , which illustrates an exemplary catheter-based electrophysiology mapping and ablation system 10. The system 10 includes multiple catheters that are percutaneously inserted by a physician 24 through the vascular system of a patient 23 and into a cavity or vasculature of a heart 12. Typically, a delivery sheath catheter is inserted into the left or right atrium near a desired location in the heart 12. Multiple catheters may then be inserted into the delivery sheath catheter to reach the desired location. The multiple catheters may include catheters dedicated to sensing intracardiac electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters dedicated to both sensing and ablation. An exemplary catheter / medical probe 14 configured to sense IEGMs is illustrated herein. To sense a target site within the heart 12, the physician 24 brings the catheter shaft (i.e., multi-layered probe tip 100) with the heart wall. For ablation, the physician 24 similarly brings the distal end of an ablation catheter to the target site for ablation.

[0021] The catheter 14 is an exemplary catheter that includes one, and preferably multiple, electrodes 102 configured to sense IEGM signals, optionally distributed across a probe tip 28 coupled to the catheter shaft, as described in more detail below. The catheter 14 may additionally include a position sensor embedded in or near the probe tip 28 to track the position and orientation of the probe tip 28. Optionally and preferably, the position sensor is a magnetic-based position sensor that includes multiple magnetic coils for sensing three-dimensional (3D) position and orientation.

[0022] The magnetic-based position sensor may operate in conjunction with a location pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field within a predetermined working volume. The real-time position of the probe tip 100 of the catheter 14 may be tracked based on the magnetic field generated by the location pad 25 and sensed by the magnetic-based position sensor. Details of magnetic-based position sensing technology are described in U.S. Patent Nos. 5,391,199; 5,443,489; 5,558,091; 6,172,499; 6,239,724; 6,332,089; 6,484,118; 6,618,612; 6,690,963; 6,788,967; and 6,892,091, each of which is incorporated herein by reference.

[0023] The system 10 includes one or more electrode patches 38 positioned for skin contact on the patient 23 to establish a position reference for the location pads 25 and impedance-based tracking of the electrodes 102. For impedance-based tracking, current is directed to the electrodes 102 and sensed at the electrode skin patches 38, thereby allowing the location of each electrode to be triangulated via the electrode patches 38. Details of impedance-based position tracking techniques are described in U.S. Patent Nos. 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182, each of which is incorporated herein by reference.

[0024] Recorder 11 displays electrograms 21 captured by body surface ECG electrodes 18 and intracardiac electrograms (IEGMs) captured by electrodes 102 on catheter 14. Recorder 11 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0025] The system 10 may include an ablation energy generator 50 adapted to deliver ablation energy to one or more electrodes 102 at the distal tip of a catheter configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radiofrequency (RF) energy, or pulsed-field ablation (PFA) energy, including unipolar or bipolar high-voltage DC pulses, such as may be used to perform irreversible electroporation (IRE), or a combination thereof.

[0026] The patient interface unit (PIU) 30 is an interface configured to establish electrical communication between the catheters, the electrophysiology equipment, a power source, and a workstation 55 that controls the operation of the system 10. The electrophysiology equipment of the system 10 may include, for example, multiple catheters, location pads 25, body surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 additionally includes processing capabilities for implementing real-time calculations of catheter position and performing ECG calculations.

[0027] The workstation 55 includes a processor unit having memory, memory or storage loaded with appropriate operating software, and user interface functionality. The workstation 55 may optionally provide multiple functions, including: (1) modeling the endocardial anatomical structure in three dimensions (3D) and rendering the model or anatomical map 20 for display on the display device 27; (2) displaying activation sequences (or other data) compiled from recorded electrograms 21 in a representative visual representation or image superimposed on the rendered anatomical map 20 on the display device 27; (3) displaying the real-time position and orientation of multiple catheters within the cardiac chambers; and (4) displaying areas of interest, such as where ablation energy is being applied, on the display device 27. One commercially available product embodying elements of the system 10 is available as the CARTO™ 3 system, commercially available from Biosense Webster, Inc., 31 Technology Drive, Suite 200, Irvine, CA 92618.

[0028] 2A and 2B provide illustrations of two exemplary probe tips 28A, 28B (also referred to herein as end effectors) configured for insertion into a patient's internal body cavity, and FIG. 3 shows an exploded view of probe tip 28A, with its components vertically exploded along vertical axis VV.

[0029] 2A and 3 , probe tip 28A extends along a longitudinal axis LA from proximal end PE (connecting to elongate shaft 29) to distal end DE and includes a first flexible circuit 100 including a plurality of electrodes 102, as well as a second flexible circuit 100′ configured identically to first flexible circuit 100. In some embodiments, the term “flexible circuit” includes thin-film circuits, flexible printed circuit boards, thin-film deposition by lithography and etching processes on substrates such as polyimide, copper, LCP, Nitinol substrates, thermoplastic polyurethane (TPU), silicone, thermoset resin, or other polymer substrates. In some embodiments, the flexible circuit layer described herein can be made primarily of polyimide. In other embodiments, it can be made of biocompatible polyimide, glass-reinforced epoxy laminate material, copper, or graphene, either alone or in combination. In some embodiments, the electrodes 102 described herein may include at least one mapping electrode and / or at least one ablation electrode and may be configured to detect electrophysiological signals or deliver ablation energy AC or DC from an energy generator to tissue according to various ablation methods mentioned above, e.g., RF, IRE, etc.

[0030] The flexible circuits 100, 100' are disposed within an insulating material 130 that extends along a planar longitudinal axis LA. The insulating material 130 can be continuous with the contact surfaces such that only the contact surfaces of at least a portion of the electrodes 102 are exposed to the ambient environment. As used herein, "ambient environment" refers to the organ in which the probe tip 100 is disposed or the external environment, such as an operating room, prior to placement within a biological organ. The insulating material 130 at least partially encapsulates and spaces apart the different layers of the probe tip 28A (e.g., the flexible circuits 100, 100' and the framework 120, which are described in more detail below) along a vertical axis VV.

[0031] The flexible substrate of each flexible circuit 100, 100' comprises a biocompatible material, extends along a plane, and has a first side and a second side. In some embodiments, the flexible substrate is formed entirely or almost entirely from the biocompatible material. Electrodes 102 are disposed on a surface of the flexible substrate. The electrodes 102 are disposed on only one side of the plane. In other words, the electrodes 102 are oriented to face away from the framework 120.

[0032] Referring particularly to FIG. 2A , each flexible circuit 100, 100′ includes a plurality of electrodes 102, a soldering pad region 104 disposed at a proximal end thereof, a central branch segment 108A, a plurality of outer branch segments 108B, 108C, and a plurality of voids 110 defined between the branch segments 108A-108C. The central branch segment 108A extends along a planar longitudinal axis LA. The electrodes 102 may include respective pairs 102A, 102B, 102C disposed along the central branch 108A (e.g., electrode 102A) and outer branch segments 108B (e.g., electrodes 102B, 102C) staggered along the longitudinal axis LA. For example, as seen in FIG. 2A , one or more of the segments of the flexible circuits 100, 100′ may include a serpentine pattern 106. Additionally, connecting outer segments 107 that do not include electrodes 102 can be provided to help define the shape of the distal tip 28 and to provide reinforcement / protection to the segments of the flexible circuit 100 that carry the electrical traces and / or electrodes. The outer branch segments 108B, 108C extend along a plane a distance away from the longitudinal axis LA. At least some of the outer branch segments 108B, 108C extend distally of the central branch segment 108A, thereby defining a recess 112 at the distal end of the end effector 28A.

[0033] As used herein, recess 112 is defined by an outer boundary OB (i.e., periphery) of the end effector that converges or recedes toward the longitudinal axis LA, whereby the outer boundary OB of the terminal portion (also referred to herein as terminal center portion TC) of flexible circuit 100 or 100′ (and also the entire end effector 28) proximate longitudinal axis LA is recessed relative to the outer boundary of at least the nearest adjacent distal terminal portion TR or TL of flexible circuit 100 or 100′, as illustratively seen in FIGURES 2A and 2B. Note that while preferred embodiments have the outer boundary OB of insulating material 130 follow the periphery of flexible circuit 100 or 100′ to define recess 112, at least the periphery of flexible circuit 100 or 100′ does not extend beyond the periphery of insulating material 130 to ensure that sharp edges of flexible circuit 100 or 100′ do not penetrate body tissue.

[0034] Note that all of the electrodes 102A-102C on the probe tip 28 described herein need not be exposed through the insulating material 130, as these unexposed electrodes may be used to sense far-field signals for noise reduction in proximity to the tissue-contacting electrodes. Similarly, far-field signals containing noise or artifacts may be reduced or canceled for an entire probe tip having a reference electrode that is not in contact with tissue, but is in contact only with blood.

[0035] Probe tip 28A may further include a framework 120A that is contiguous with or within insulating material 130. In embodiments in which probe tip 28 includes framework 120A, framework 120A may be disposed directly on flexible circuit 100, with little or no insulating material 130 disposed between the two. In other embodiments, an insulating layer of insulating material 130 may space framework 120A from flexible circuit 100, 100'.

[0036] In some embodiments, framework 120A is disposed within insulating material 130 and is substantially planar along longitudinal axis LA such that longitudinal axis LA is parallel or coincident with framework 120A. In the embodiment shown in FIG. 2, position sensor 140A can be provided sandwiched between and generally parallel to flexible circuit 100 and spine framework 120A. In some embodiments, framework 120A is formed from a flexible, elastic material. By way of example, framework 120A can be formed from a shape memory alloy such as nickel-titanium, also known as nitinol, cobalt chromium, stainless steel, and / or other alloys that exhibit pseudoelastic and / or superelastic properties.

[0037] Stated another way, one aspect of the present disclosure provides a probe tip 28 having a planar framework 120A that bisects two flat thermoformed portions of a flexible insulating mass 130, with at least one flexible circuit 100 (and / or flexible circuit 100') disposed on one side of the framework 120A.

[0038] The framework 120A may be a component of the probe tip 28 that is separate and distinct from, and disposed proximate to, the first flexible circuit 100. In this case, an insulating material 130 may further be disposed between the framework 120A and the second flexible circuit 100. The framework 120A may be formed from a planar or cylindrical stock of material using any suitable method. For example, the framework 120A may be formed by cutting, laser cutting, stamping, etc.

[0039] The insulating material 130 may include one or more sheets fused together adjacent to the framework 120 into a single, continuous, generally planar insulating mass 130. This insulating material 130 also serves to enhance the atraumatic nature of the probe tip 100 and to protect the subject from sharp edges. The insulating material 130 may include a polymer. The insulating material 130 may be thermoformed around at least a portion of the first flexible circuit 110, the second flexible circuit 100, and the framework 120A. The polymer may include TPU or other thermoforming or molding material suitable for such thermoforming.

[0040] Additionally, although insulating material 130 is shown as flat in these figures, insulating material 130 may be shaped, corrugated, ribbed, raised, concave, convex, or otherwise configured such that the overall contour of insulating material 130 provides the physical and / or mechanical properties, such as stiffness and flexure along multiple axes, required by probe tip 28 referred to above.

[0041] FIG. 2B shows an alternative configuration of distal tip 28B having a different shape than distal tip 28A of FIG. 2A, but which still defines recess 112 by having at least some of its outer branch segments, its spine framework 120B, and its position sensor 140B extend further along longitudinal axis LA than the central branch segment.

[0042] 4-5B, further features of the disclosed technology are shown in more detail. In use, when a distal tip 28 (e.g., the distal tip 28A described above) is retracted into an insertion tool 200 (FIGS. 5A-5B), the distal tip 28 must deform and / or roll so that all of the material fits within a predetermined circumference (see, e.g., FIGS. 5A and 5B). Therefore, as shown particularly in FIG. 5A, the thickness T of the distal tip 28 directly correlates to the resulting inner diameter ID of the distal tip 28 when it collapses within the insertion tool 200. If the inner diameter ID is too small, the width of the distal tip 28 will not provide sufficient coverage in a clinical setting. In actual use, particularly if excess material is used (discussed in more detail in the next paragraph), the distal tip 28 will not collapse into a perfectly cylindrical shape, but rather will collapse on itself to fill the interior space of the insertion tool 200, such as in the orientation shown in FIG. 5B. Nevertheless, if the inner diameter ID is too large, the distal tip 28 may not collapse predictably, and the collapse may cause distortion and / or failure of subcomponents (e.g., the flexible circuit 100).

[0043] Thus, the distal tip 28 of the present disclosure employs a combination of material voids 110 between segments where electrodes 102 are not needed / used and recesses 112 at the distal end DE, as shown in FIG. 4. In any given cross-section of the distal tip 28 taken along the longitudinal axis LA and perpendicular to the longitudinal axis 28 (e.g., sections S1, S2, S3, S4, S5, and S6), each section S1, S2, S3, S4, S5, S6 has a predetermined maximum overall width of material (i.e., the voids 110 and recesses 112 do not count toward its width) based on the desired access sheath French size compatibility of the distal tip. In other words, the sum of the widths of the central branch segment and outer branch segments of the distal tip 28 and the widths of the segments 108A-108C of the flexible circuit 100 transverse to the longitudinal axis LA is less than a threshold width at any given location along the distal tip 28. In other words, the linear cross-sectional measurement of the distal tip 28A is minimized at all locations along the longitudinal axis LA. In the example described herein, the maximum overall width of material at any given cross-section of the distal tip 28 is as close as possible to π(d-2T), where d is the inner diameter of the desired access sheath / insertion tool 200 and T is the thickness of the distal tip 28. This allows the distal tip 28 to be folded similarly to the depiction shown in FIG. 5A. Any width greater than this must be folded inward, as shown in FIG. 5B. As a non-limiting example, if the sheath inner diameter is 2.9 mm and the distal tip thickness is 0.4 mm, the maximum material at any cross-section should be less than 6.6 mm (the overall width of the distal tip 28 is approximately 11 mm to 12 mm).

[0044] To at least partially define these gaps 110, the outer branch segments 108B, 108C extend outward from the central branch segment 108A at an oblique angle relative to the central branch segment 108A and the longitudinal axis LA, relative to at least a portion of the outer branch segments 108B, 108C. More specifically, a proximal portion of each outer branch segment 108B, 108C (see, e.g., the bottom of FIG. 4) extends outward from the central branch segment 108A at an oblique angle relative to the longitudinal axis LA, and a distal portion of each outer branch segment 108B, 108C (see, e.g., the top of FIG. 4) extends parallel to the central branch segments 108A, 108B.

[0045] For example, as seen in FIGS. 2A and 4, the electrodes 102 are staggered, which allows the distal end DE to be more easily configured to define the recess 112 (as seen in FIG. 2A, only certain electrodes 102B are disposed at the distal end DE). More specifically, the plurality of electrodes includes a first set 102A of electrodes 102 disposed on the central branch segment 108A and a second set 102B of electrodes 102 disposed on / along adjacent branches 108B of the plurality of outer branch segments 108B, 108C. The first set 102A of electrodes 102 and the second set 102B of electrodes 102 are not aligned with one another (i.e., staggered) in a direction transverse to the longitudinal axis LA. In this configuration, the insulating material 130 has a wave-like pattern in a direction transverse to the longitudinal axis LA, thereby reducing the total amount of material in any given linear cross-sectional measurement.

[0046] In addition to the above, the outer branch segments 108B, 108C may further include a first set of outer branch segments 108B and a second set of outer branch segments 108C (see symmetrical left and right sides of the distal tip 28A, each set formed by one respective segment on the left side and one respective segment on the right side). The first set of outer branch segments 108B extends distally from the central branch segment 108A, and the second set of outer branch segments 108C terminates in a position generally aligned with the central branch segment 108A transverse to the longitudinal axis LA, with a bridge segment connecting the distal-most ends of the segments 108A, 108B, and 108C. In this configuration, the electrodes 102C disposed along the second set of outer branch segments 108C are aligned with the electrodes 102A disposed along the central branch segment 108A.

[0047] It should be noted that the alternative distal tip 28B employs a similar configuration of the flexible circuit 110, with the primary difference being how the other layers (e.g., framework 120B and position sensor 140B) are configured while still maintaining the aforementioned minimized linear cross-sectional measurements of the distal tip 28B (excluding the voids 110 and recesses 112).

[0048] 6A-6B, an alternative configuration 28C of the distal tip 28 includes the aforementioned void 110 and also includes a distal end DE that is shaped to be less than a threshold width at any given location along the end effector 28 (as in the previous embodiment). The distal tip 28C includes a position sensor 140C that extends along a longitudinal axis LA from the proximal end PE to the distal end DE. The position sensor includes a central segment 142 that extends along the longitudinal axis and multiple outer segments 144, 146, 148 that extend at an oblique angle from the central segment 142. The distal-most outer segment 148 together define a recess 141 that helps reduce strain when the distal tip 28C is retracted into an insertion tool 200 or another delivery sheath. Additionally, electrical traces on the position sensor 140C exit in a direction parallel to the central segment 142. In the design shown / described herein, the primary folding direction of the distal tip 28 is perpendicular to the plane of the position sensor 140C and is mostly concentrated at the proximal end of the distal tip 28. The traces are parallel to the centerline in this example due to the use of rolled annealed copper cladding (where the copper grain is large in one direction). Note also that the central segment 142 is narrow, which helps reduce the contribution of twist to the position sensor 140C in this region.

[0049] In this example, position sensor 140C has one or more loops with traces that, when exposed to a magnetic field, induce a current indicative of the position of probe tip 28C. In this example, referring to FIGURE 6B, position sensor 140C may include three loops: a first loop forming a loop on outer segments 144, 148 and central segment 142 on the left side of longitudinal axis LA, a second loop forming a loop on outer segments 144, 148 and central segment 142 on the right side of longitudinal axis LA, one overlapping loop, and a third loop forming a loop on outer segments 146, 148 and central segment 142 on either side of longitudinal axis LA so as to partially overlap distal regions of the first and second loops.

[0050] 3, it should be noted that position sensor 140 in another embodiment can take a similar form / function to that described with respect to Figures 6A-6B, and include the same or similar segments 142, 144, 146, 148, and recess 141, although with a slightly different shape. In this embodiment, recess 141 is at least partially aligned with recess 112 in the distal end DE of probe tip 28A.

[0051] Reference is now made to Figures 7A-7E, which illustrate another aspect of the disclosed technology. With specific reference to Figure 7A, the distal portion of distal tip 28 of Figure 2A is shown, with an example flexible substrate of flexible circuit 100 bounded by a dashed box that is expanded in subsequent Figures 7B-7E.

[0052] A typical flexible circuit has a high aspect ratio, which results in a high preference for bending out of the plane (i.e., along its weak axis) relative to in the plane (i.e., along one of its strong axes). This causes the typical flexible circuit to experience high compressive and tensile stresses / strains, as well as torsional strains, when subjected to in-plane bending. One such flexible circuit is the flexible circuit 100A shown in FIG. 7B, which includes a substrate 114 and one or more traces 116. FIG. 7B includes a detailed cross-sectional view of a portion of the flexible circuit 100A enclosed in a dashed box to highlight the differences from the following example described with respect to FIG. 7C.

[0053] To address stress / strain issues during bending, any of the previously described embodiments of the distal tip 28A may be provided with a flexible circuit 100B that allows free movement about all three axes, as seen in FIG. 7C . In this embodiment, traces 116 extend along the flexible circuit 100B, and a substrate 114 supports each trace 116. Rather than providing all of the traces 116 on one substrate 114 (as in FIG. 7B ), the traces 116 are singulated on at least a portion of the flexible substrate 114 such that the flexible substrate 114 has multiple individual beams 114A corresponding to and supporting each trace 116 (e.g., individual sections and the entire flexible circuit 100B can be singulated as needed). The singulated trace 116-beam 114A pairs define multiple gaps 118 between adjacent traces 116. In this configuration, the aspect ratio of the flexible circuit 100B can be significantly reduced, which improves its bendability along the weak and strong axes and also allows it to apply torque more easily.

[0054] In the example shown in FIG. 7C, the flexible circuit 100B is cut between pre-etched traces 116. However, alternative configurations may be used. FIG. 7D shows a portion of another flexible circuit 100C in which the traces 116 are created by cutting directly through the metal, thereby defining gaps 118 between the traces. Additionally, as seen in FIG. 7E with flexible circuit 100D, the substrate 114 and at least some of the traces 116 may further define strain relief loops 115 that promote in-plane bending by defining wider gaps 118 between adjacent strain relief loops 115 than the gaps 118 between other sections of the flexible circuit 100D.

[0055] In addition to the above, FIG. 8 illustrates a flow diagram of a method 800 of fabricating flexible circuits 100B, 100C for a medical probe 14 in accordance with the disclosed technology. A substrate is formed (802) extending along a plane. A conductive material is disposed (804) along the substrate. In some embodiments, disposing the conductive material along the substrate (804) includes disposing individual traces of the conductive material along the substrate (e.g., as in the example of FIG. 7C where the traces 116 are pre-etched on the substrate 114). In some embodiments, disposing the conductive material along the substrate (804) includes disposing a single continuous piece of the conductive material along the substrate (e.g., as in the example of FIG. 7D where the traces 116 are formed from a single piece of metal). The conductive material and substrate are cut (806) along a curve in the flexible substrate such that the flexible substrate and conductive material form a plurality of individual branches (with gaps between them). In some embodiments, cutting the conductive material and substrate (806) includes cutting the conductive material and substrate using a laser (806). In some embodiments, a strain relief loop is formed in at least one of the plurality of individual branches (810).

[0056] 9A-12 are now referenced in conjunction with one another. The planar distal tip 28 described herein should, in use, have a low coefficient of friction during insertion of the tip 28 through an insertion tool 200 into a patient 23. Additionally, it is important that unwanted information (i.e., noise) does not interfere with the proper function of the electrode 102. Accordingly, the present disclosure includes a method 1200 of manufacturing an end effector 28 for a medical probe 14, which method 1200 includes coating an electrode 102 (as shown in FIG. 9A) with an impedance-reducing coating 102A' (as shown in FIG. 9A) to improve the signal-to-noise ratio of the electrode 102 and a hydrophilic coating 102B' (FIG. 9B) to reduce friction (i.e., coating 102B' is lubricious) and protect the electrode 102 from contamination, with the final end effector 28 including a protected, coated electrode 102' having uniform lubricity throughout the end effector 28. With the coating, a textured finish is present, giving the electrode 102' a satin appearance (compared to the matte appearance when uncoated). Note that the hydrophilic coating 102B' can also mechanically protect the impedance-reducing coating 102A' even when not on top (fully or partially) of the noise-reducing coating due to the lubricious properties of the hydrophilic coating 102B' (which may be hydrogel-based, for example), thus allowing for reduced frictional effects. In other words, in use, the hydrophilic coating 102B' allows the distal tip 28 to slide more easily, preventing it from getting caught on something that could damage the impedance-reducing coating 102A'.

[0057] Referring to FIG. 12 , method 1200 may include the following: An electrode 102 is formed on a flexible circuit 100 (1202). The electrode 102 is coated with an impedance-reducing coating 102A′ (1204). The distal tip 28, including the electrode 102′, is further coated with a hydrogel-based hydrophilic coating 102B′ disposed at least partially on the impedance-reducing coating 102A′ (1206), resulting in a coated electrode 102′. Furthermore, it should be noted that when the hydrogel-based hydrophilic coating 102B′ is applied immediately after the impedance-reducing coating 102A′, it allows the impedance-reducing coating 102A′ to remain hydrated, and no hydration and / or activation is required prior to use. In some embodiments, the hydrophilic coating comprises a hydrogel, such as LUBRICENT™, available from Harland Medical Systems as of the filing date of this application. In some embodiments, most or all of the distal tip 28, including the coated electrode 102', is optionally further coated with another lubricious coating 102C' (FIG. 9B).

[0058] FIG. 10 is a graphical representation 1000 of electrode resistance measured over a range of frequencies. Lines 1002 and 1004 show the results for an electrode 102' coated with a hydrophilic coating 102B', while lines 1006 and 1008 show the results for an electrode 102' not coated with a hydrophilic coating 102B'. As can be seen in FIG. 10, the application of a hydrophilic coating does not result in a statistically significant increase in impedance. Furthermore, FIG. 11A illustratively shows a multivariate chart 1100A illustrating the signal from an electrode 102' having a hydrophilic coating 102B', and FIG. 11B shows a multivariate chart 1100B of the resistance of the coated and uncoated electrodes. As illustrated by these figures, the addition of the coating 102B' does not adversely affect the signal performance of the electrode 102' to any significant extent.

[0059] The techniques of the present disclosure described herein can be further understood in accordance with the following clauses.

[0060] Clause 1. An end effector comprising: a flexible insulating material extending along a plane; a framework disposed within the flexible insulating material; and a flexible circuit disposed within the flexible insulating material and spaced from the framework, the flexible circuit including: a central branch segment extending along a longitudinal axis of the plane; a plurality of outer branch segments extending along the plane a distance from the longitudinal axis, at least some of the outer branch segments extending distally of the central branch segment, thereby defining a recess at a distal end of the end effector proximate the longitudinal axis; and a plurality of electrodes disposed along the central branch segment and the plurality of outer branch segments.

[0061] Clause 2. An end effector further comprising another flexible circuit disposed within the flexible insulating material and spaced apart from the framework, the other flexible circuit being spaced apart from the flexible circuit on an opposite side of the framework, the other flexible circuit including: a central branch segment extending along a longitudinal axis of a plane; a plurality of outer branch segments extending along the plane a distance away from the longitudinal axis, at least some of the outer branch segments extending distally of the central branch segment thereby defining a recess at a distal end of the end effector proximate the longitudinal axis; and a plurality of electrodes disposed along the central branch segment and the plurality of outer branch segments.

[0062] Clause 3. An end effector as described in Clause 1, wherein the plurality of electrodes includes a first set of electrodes arranged on a central branch segment and a second set of electrodes arranged along adjacent branches of the plurality of outer branch segments, and the first set of electrodes and the second set of electrodes are not aligned with each other in a direction transverse to the longitudinal axis.

[0063] Clause 4. An end effector as described in Clause 3, wherein the plurality of outer branch segments includes a first set of outer branch segments and a second set of outer branch segments, the first set of outer branch segments extending distal to the central branch segment, and the second set of outer branch segments terminating at a position approximately aligned with the central branch segment in a direction transverse to the longitudinal axis.

[0064] Clause 5. The end effector of clause 4, wherein the electrodes disposed along the second set of outer branch segments are aligned with the electrodes disposed along the central branch segment.

[0065] Clause 6. The end effector of clause 1, wherein the end effector further defines one or more gaps between each of the plurality of outer branch segments and the central branch segment.

[0066] Clause 7. An end effector as described in Clause 6, wherein the sum of the widths of the central branch segment and the plurality of outer branch segments in a direction transverse to the longitudinal axis is less than a threshold width at any given location along the end effector.

[0067] Clause 8. The end effector of clause 1, wherein the plurality of outer branch segments extend outwardly from the central branch segment at an oblique angle relative to the central branch segment for at least a portion of the plurality of outer branch segments.

[0068] Clause 9. The end effector of clause 8, wherein the proximal portions of the outer branch segments extend outward from the central branch segment at an oblique angle to the longitudinal axis, and the distal portions of the outer branch segments extend parallel to the central branch segment.

[0069] Clause 10. An end effector as described in Clause 1, wherein the flexible circuit further includes a plurality of traces extending along the flexible circuit and a substrate supporting each trace of the plurality of traces, the substrate and the plurality of traces defining a plurality of gaps between each of the plurality of traces.

[0070] Clause 11. The end effector of clause 10, wherein the substrate and at least some of the plurality of traces further define strain relief loops.

[0071] Clause 12. The end effector of clause 1, further comprising a position sensor extending along the plane.

[0072] Clause 13. An end effector as described in clause 12, wherein the position sensor comprises a recess configured to at least partially align with a recess in the distal end of the end effector.

[0073] Clause 14. The end effector of clause 1, wherein the end effector is coated with a lubricious coating.

[0074] Clause 15. The end effector of clause 1, wherein each of the plurality of electrodes is coated with a hydrophilic coating.

[0075] Clause 16. The end effector of clause 15, wherein the hydrophilic coating comprises a hydrogel.

[0076] Clause 17. The end effector of clause 1, wherein each of the plurality of electrodes is coated with an impedance-reducing coating.

[0077] Clause 18. The end effector of clause 17, wherein the impedance-reducing coating comprises at least one of poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, iridium oxide, platinum-iridium, or a combination thereof.

[0078] Clause 19. The end effector of clause 17, wherein a hydrophilic coating is at least partially disposed over the impedance-reducing coating.

[0079] Clause 20. An end effector comprising: a flexible insulating material extending along a plane; a framework disposed within the flexible insulating material; a first flexible circuit disposed within the flexible insulating material and spaced apart from the framework on one side of the framework; and a second flexible circuit disposed within the flexible insulating material and spaced apart from both the framework and the first flexible circuit, wherein each of the first flexible circuit and the second flexible circuit comprises a central branch segment extending along a longitudinal axis of the plane, a first set of electrodes disposed on the central branch segment, a plurality of outer branch segments extending along the plane a distance away from the longitudinal axis, and a second set of electrodes disposed along adjacent outer branch segments, wherein the first set of electrodes and the second set of electrodes are not aligned with each other in a direction transverse to the longitudinal axis.

[0080] Clause 21. An end effector as described in Clause 20, wherein at least some of the outer branch segments of each of the first and second flexible circuits extend distal to the respective central branch segments, thereby defining a recess in the distal end of the end effector.

[0081] Clause 22. An end effector as described in Clause 20, wherein the multiple outer branch segments of the first flexible circuit and the second flexible circuit each include a first set of outer branch segments and a second set of outer branch segments, the first set of outer branch segments extending distal to the respective central branch segments, and the second set of outer branch segments terminating at a position approximately aligned with the respective central branch segments in a direction transverse to the longitudinal axis.

[0082] Clause 23. An end effector as described in Clause 22, wherein electrodes arranged along the second set of outer branch segments of the first flexible circuit are aligned with electrodes arranged along the central branch segment of the first flexible circuit.

[0083] Clause 24. An end effector as described in Clause 20, wherein the end effector further defines one or more gaps between each of the plurality of outer branch segments of the first flexible circuit and the central branch segment of the first flexible circuit.

[0084] Clause 25. An end effector as described in Clause 24, wherein the sum of the widths of the central branch segment of the first flexible circuit and the multiple outer branch segments of the first flexible circuit in a direction transverse to the longitudinal axis is less than a threshold width at any given position along the end effector.

[0085] Clause 26. An end effector as described in Clause 25, wherein the multiple outer branch segments of the first flexible circuit extend outward from the central branch segment of the first flexible circuit at an oblique angle to the central branch segment of the first flexible circuit for at least a portion of the multiple outer branch segments of the first flexible circuit.

[0086] Clause 27. An end effector as described in Clause 26, wherein a proximal portion of the outer branch segment of the first flexible circuit extends outward from the central branch segment of the first flexible circuit at an oblique angle to the longitudinal axis, and a distal portion of the outer branch segment of the first flexible circuit extends parallel to the central branch segment of the first flexible circuit.

[0087] Clause 28. An end effector as described in Clause 20, wherein the first flexible circuit further includes a plurality of traces extending along the first flexible circuit and a substrate supporting each trace of the plurality of traces, the substrate and the plurality of traces defining a plurality of gaps between each of the plurality of traces.

[0088] Clause 29. The end effector of clause 28, wherein the substrate and at least some of the plurality of traces further define strain relief loops.

[0089] Clause 30. The end effector of clause 21, further comprising a position sensor extending along the plane.

[0090] Clause 31. An end effector as described in Clause 30, wherein the position sensor comprises a recess configured to at least partially align with a recess in the distal end of the end effector.

[0091] Clause 32. The end effector of clause 20, wherein the end effector is coated with a lubricious coating.

[0092] Clause 33. The end effector of clause 20, wherein each of the plurality of electrodes is coated with a hydrophilic coating.

[0093] Clause 34. The end effector of clause 33, wherein the hydrophilic coating comprises a hydrogel.

[0094] Clause 35. The end effector of clause 20, wherein each of the plurality of electrodes is coated with an impedance-reducing coating.

[0095] Clause 36. An end effector as described in clause 35, wherein the impedance-reducing coating comprises at least one of poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, iridium oxide, or platinum-iridium.

[0096] Clause 37. The end effector of clause 35, wherein a hydrophilic coating is at least partially disposed over the impedance-reducing coating.

[0097] Clause 38. A method of manufacturing an end effector for a medical probe, the method comprising forming an electrode on a flexible circuit and coating the electrode with an impedance-reducing coating.

[0098] Clause 39. The method of clause 38, wherein the hydrophilic coating comprises a hydrogel.

[0099] Clause 40. The method of clause 38, further comprising coating the end effector, including the electrodes, with a hydrophilic coating.

[0100] Clause 41. The method of clause 38, wherein the impedance-reducing coating comprises at least one of poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, iridium oxide, or platinum-iridium.

[0101] Clause 42. A method of manufacturing a flexible circuit for a medical probe, the method comprising: forming a substrate extending along a plane; disposing a conductive material along the substrate; and cutting the conductive material and the substrate along a curve of the flexible substrate such that the flexible substrate and the conductive material form a plurality of individual branches.

[0102] Clause 43. The method of clause 42, wherein disposing the conductive material along the substrate includes disposing individual traces of the conductive material along the substrate.

[0103] Clause 44. The method of clause 42, wherein disposing the conductive material along the substrate includes disposing a single continuous portion of the conductive material along the substrate.

[0104] Clause 45. The method of clause 42, further comprising forming a strain relief loop in at least one of the plurality of individual branches.

[0105] Clause 46. The method of clause 42, wherein cutting the conductive material and the substrate includes cutting the conductive material and the substrate using a laser.

[0106] The above-described embodiments are cited as examples, and the technology of the present disclosure is not limited to what has been specifically shown and described in the above specification. Rather, the scope of the technology of the present disclosure includes both combinations and subcombinations of the various features described above, as well as variations and modifications thereof that would occur to one skilled in the art upon reading the foregoing description and that are not disclosed in the prior art.

[0107] [Embodiment] (1) An end effector, a flexible insulating material extending along a plane; a framework disposed within the flexible insulating material; a flexible circuit disposed within the flexible insulating material and spaced apart from the framework, a central branch segment extending along a longitudinal axis of said plane; a plurality of outer branch segments extending along the plane a distance away from the longitudinal axis, at least some of the outer branch segments extending distally of the central branch segment thereby defining a recess in the distal end of the end effector proximate the longitudinal axis; a flexible circuit including a plurality of electrodes disposed along the central branch and the plurality of outer branch segments. (2) The method further comprises: disposing another flexible circuit within the flexible insulating material and spaced apart from the framework, the other flexible circuit being spaced apart from the flexible circuit on an opposite side of the framework; and the other flexible circuit comprising: a central branch segment extending along a longitudinal axis of said plane; a plurality of outer branch segments extending along the plane a distance away from the longitudinal axis, at least some of the outer branch segments extending distally of the central branch segment thereby defining a recess in the distal end of the end effector proximate the longitudinal axis; An end effector as described in embodiment 1, comprising a plurality of electrodes arranged along the central branch and the plurality of outer branch segments. (3) The plurality of electrodes a first set of electrodes disposed on the central branch segment; and a second set of electrodes arranged along adjacent ones of the plurality of outer branch segments, wherein the first set of electrodes and the second set of electrodes are not aligned with each other in a direction transverse to the longitudinal axis. (4) An end effector as described in embodiment 3, wherein the plurality of outer branch segments include a first set of outer branch segments and a second set of outer branch segments, the first set of outer branch segments extending distal to the central branch segment, and the second set of outer branch segments terminating at a position approximately aligned with the central branch segment in a direction transverse to the longitudinal axis. (5) An end effector as described in embodiment 4, wherein electrodes arranged along the second set of outer branch segments are aligned with electrodes arranged along the central branch segment.

[0108] (6) An end effector as described in embodiment 1, wherein the end effector further defines one or more gaps between each of the plurality of outer branch segments and the central branch segment. (7) An end effector as described in embodiment 6, wherein the sum of the widths of the central branch segment and the multiple outer branch segments in a direction transverse to the longitudinal axis is less than a threshold width at any given position along the end effector. (8) An end effector as described in embodiment 1, wherein the outer branch segments extend outward from the central branch segment at an oblique angle relative to the central branch segment for at least a portion of the outer branch segments. (9) An end effector as described in embodiment 8, wherein a proximal portion of the outer branch segment extends outward from the central branch segment at an oblique angle to the longitudinal axis, and a distal portion of the outer branch segment extends parallel to the central branch segment. (10) An end effector as described in embodiment 1, wherein the flexible circuit further includes a plurality of traces extending along the flexible circuit and a substrate supporting each trace of the plurality of traces, the substrate and the plurality of traces defining a plurality of gaps between each of the plurality of traces.

[0109] (11) An end effector, a flexible insulating material extending along a plane; a framework disposed within the flexible insulating material; a first flexible circuit disposed within the flexible insulating material and spaced apart from the framework on one side of the framework; a second flexible circuit disposed within the flexible insulating material and spaced apart from both the framework and the first flexible circuit, wherein each of the first flexible circuit and the second flexible circuit comprises: a central branch segment extending along a longitudinal axis of said plane; a first set of electrodes disposed on the central branch segment; a plurality of outer branch segments extending along the plane at a distance from the longitudinal axis; a second set of electrodes disposed along an adjacent lateral branch segment, wherein the first set of electrodes and the second set of electrodes are not aligned with one another transverse to the longitudinal axis. (12) An end effector as described in embodiment 11, wherein at least some of the outer branch segments of the first flexible circuit and the second flexible circuit extend distally of the respective central branch segments, thereby defining a recess in the distal end of the end effector. (13) An end effector as described in embodiment 11, wherein the plurality of outer branch segments of the first flexible circuit and the second flexible circuit each include a first set of outer branch segments and a second set of outer branch segments, the first set of outer branch segments extending distally of the respective central branch segments, and the second set of outer branch segments terminating at a position approximately aligned with the respective central branch segments in a direction transverse to the longitudinal axis. (14) An end effector as described in embodiment 13, wherein electrodes disposed along the second set of outer branch segments of the first flexible circuit are aligned with electrodes disposed along the central branch segment of the first flexible circuit. (15) The end effector of embodiment 11, wherein the end effector further defines one or more gaps between each of the outer branch segments of the first flexible circuit and the central branch segment of the first flexible circuit.

[0110] (16) The end effector of embodiment 15, wherein the sum of the widths of the central branch segment of the first flexible circuit and the plurality of outer branch segments of the first flexible circuit in a direction transverse to the longitudinal axis is less than a threshold width at any given location along the end effector. (17) The end effector of embodiment 16, wherein the outer branch segments of the first flexible circuit extend outwardly from the central branch segment of the first flexible circuit at an oblique angle relative to the central branch segment of the first flexible circuit for at least a portion of the outer branch segments of the first flexible circuit. (18) The end effector of embodiment 17, wherein proximal portions of the outer branch segments of the first flexible circuit extend outward from the central branch segment of the first flexible circuit at an oblique angle to the longitudinal axis, and distal portions of the outer branch segments of the first flexible circuit extend parallel to the central branch segment of the first flexible circuit. (19) An end effector as described in embodiment 11, wherein the first flexible circuit further includes a plurality of traces extending along the first flexible circuit and a substrate supporting each trace of the plurality of traces, the substrate and the plurality of traces defining a plurality of gaps between each of the plurality of traces. (20) An end effector as described in embodiment 19, wherein the substrate and at least some of the traces of the plurality of traces further define strain relief loops.

Claims

1. An end effector, a flexible insulating material extending along a plane; a framework disposed within the flexible insulating material; a flexible circuit disposed within the flexible insulating material and spaced apart from the framework, a central branch segment extending along a longitudinal axis of said plane; a plurality of outer branch segments extending along the plane a distance away from the longitudinal axis, at least some of the outer branch segments extending distally of the central branch segment thereby defining a recess in the distal end of the end effector proximate the longitudinal axis; a flexible circuit including a plurality of electrodes disposed along the central branch and the plurality of outer branch segments.

2. and a flexible circuit disposed within the flexible insulating material and spaced apart from the framework, the flexible circuit being spaced apart from the flexible circuit on an opposite side of the framework, the flexible circuit comprising: a central branch segment extending along a longitudinal axis of said plane; a plurality of outer branch segments extending along the plane a distance away from the longitudinal axis, at least some of the outer branch segments extending distally of the central branch segment thereby defining a recess in the distal end of the end effector proximate the longitudinal axis; and a plurality of electrodes disposed along the central branch and the plurality of outer branch segments.

3. The plurality of electrodes a first set of electrodes disposed on the central branch segment; and a second set of electrodes disposed along adjacent ones of the plurality of outer branch segments, wherein the first and second sets of electrodes are misaligned with one another transverse to the longitudinal axis.

4. 4. The end effector of claim 3, wherein the plurality of outer branch segments includes a first set of outer branch segments and a second set of outer branch segments, the first set of outer branch segments extending distally from the central branch segment, and the second set of outer branch segments terminating in a position generally aligned with the central branch segment in a direction transverse to the longitudinal axis.

5. The end effector of claim 4 , wherein electrodes disposed along the second set of outer branch segments are aligned with electrodes disposed along the central branch segment.

6. The end effector of claim 1 , wherein the end effector further defines one or more gaps between each of the plurality of outer branch segments and the central branch segment.

7. The end effector of claim 6 , wherein a sum of the widths of the central branch segment and the outer branch segments transverse to the longitudinal axis is less than a threshold width at any given location along the end effector.

8. The end effector of claim 1 , wherein the outer branch segments extend outwardly from the central branch segment at an oblique angle relative to the central branch segment for at least a portion of the outer branch segments.

9. The end effector of claim 8 , wherein a proximal portion of the outer branch segment extends outward from the central branch segment at an oblique angle relative to the longitudinal axis, and a distal portion of the outer branch segment extends parallel to the central branch segment.

10. 2. The end effector of claim 1, wherein the flexible circuit further includes a plurality of traces extending along the flexible circuit and a substrate supporting each trace of the plurality of traces, the substrate and the plurality of traces defining a plurality of gaps between each of the plurality of traces.

11. An end effector, a flexible insulating material extending along a plane; a framework disposed within the flexible insulating material; a first flexible circuit disposed within the flexible insulating material and spaced apart from the framework on one side of the framework; a second flexible circuit disposed within the flexible insulating material and spaced apart from both the framework and the first flexible circuit, wherein each of the first flexible circuit and the second flexible circuit comprises: a central branch segment extending along a longitudinal axis of said plane; a first set of electrodes disposed on the central branch segment; a plurality of outer branch segments extending along the plane at a distance from the longitudinal axis; a second set of electrodes disposed along an adjacent lateral branch segment, wherein the first set of electrodes and the second set of electrodes are not aligned with one another transverse to the longitudinal axis.

12. 12. The end effector of claim 11, wherein at least some of the outer branch segments of the first and second flexible circuits extend distally of the respective central branch segments, thereby defining a recess in a distal end of the end effector.

13. 12. The end effector of claim 11, wherein the plurality of outer branch segments of the first flexible circuit and the second flexible circuit each include a first set of outer branch segments and a second set of outer branch segments, the first set of outer branch segments extending distally of the respective central branch segments, and the second set of outer branch segments terminating in a position generally aligned with the respective central branch segments in a direction transverse to the longitudinal axis.

14. 14. The end effector of claim 13, wherein electrodes disposed along the second set of outer branch segments of the first flexible circuit are aligned with electrodes disposed along the central branch segment of the first flexible circuit.

15. The end effector of claim 11 , wherein the end effector further defines one or more gaps between each of the outer branch segments of the first flexible circuit and the central branch segment of the first flexible circuit.

16. 16. The end effector of claim 15, wherein a sum of widths of the central branch segment of the first flexible circuit and the plurality of outer branch segments of the first flexible circuit in a direction transverse to the longitudinal axis is less than a threshold width at any given location along the end effector.

17. 17. The end effector of claim 16, wherein the outer branch segments of the first flexible circuit extend outwardly from the central branch segment of the first flexible circuit at an oblique angle relative to the central branch segment of the first flexible circuit for at least a portion of the outer branch segments of the first flexible circuit.

18. 18. The end effector of claim 17, wherein proximal portions of the outer branch segments of the first flexible circuit extend outward from the central branch segment of the first flexible circuit at an oblique angle to the longitudinal axis and distal portions of the outer branch segments of the first flexible circuit extend parallel to the central branch segment of the first flexible circuit.

19. 12. The end effector of claim 11, wherein the first flexible circuit further includes a plurality of traces extending along the first flexible circuit and a substrate supporting each trace of the plurality of traces, the substrate and the plurality of traces defining a plurality of gaps between each of the plurality of traces.

20. The end effector of claim 19 , wherein the substrate and at least some of the traces of the plurality of traces further define strain relief loops.

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