Methods for forming spline using flexible circuit assembly and electrode assemblies including the same

Abstract

To form a spline for electrode assemblies using a flexible circuit assembly.SOLUTION: A method of forming a spline 400 for an electrode assembly includes providing a structural member 404 including a first surface and a second surface. The method also includes providing a flexible circuit assembly 402 including: a plurality of electrodes 414; and at least one flexible circuit substrate 416 having a contact surface and an outer surface opposite the contact surface. The electrodes are disposed on the outer surface of the at least one flexible circuit substrate. The method includes positioning the flexible circuit assembly relative to the structural member such that a first set of electrodes is aligned with the first surface and a second set of electrodes is aligned with the second surface. The method also includes coupling the at least one flexible circuit substrate to at least one of the structural member and the at least one flexible circuit substrate.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 021,737, filed on May 8, 2020, the disclosure of which is hereby incorporated by reference in its entirety.

Background Art

[0002] The present disclosure generally relates to medical devices used in the human body. In particular, the present disclosure relates to a method of forming a spline for an electrode assembly using a flexible circuit assembly.

[0003] Electrophysiology catheters are used, for example, in various diagnostic, therapeutic, and / or mapping and ablation procedures to diagnose and / or correct conditions such as atrial arrhythmias, including ectopic atrial tachycardia, atrial fibrillation, and atrial flutter.

[0004] Typically, to perform such diagnostic, therapeutic, and / or mapping and ablation procedures, a catheter is deployed and manipulated through a patient's vascular vasculature to a desired site, e.g., a site within the patient's heart. The catheter typically carries one or more electrodes that can be used, for example, for cardiac mapping or diagnosis, ablation, and / or other therapeutic delivery modes, or both. Ablation therapy can be used to treat various conditions that afflict human anatomical structures, including atrial or cardiac arrhythmias. When tissue is ablated or at least receives ablation energy generated by an ablation generator and delivered by an ablation catheter, damage is formed within the tissue. Electrodes mounted on or within the ablation catheter are used to create tissue necrosis within the heart tissue to correct conditions such as atrial arrhythmias (including, but not limited to, ectopic atrial tachycardia, atrial fibrillation, and atrial flutter). Arrhythmias can cause various dangerous conditions, including loss of synchronous atrioventricular contraction and stasis of blood flow. The main cause of atrial arrhythmias is thought to be vagal electrical signals within the left or right atrium of the heart. The ablation catheter delivers ablation energy (e.g., high-frequency energy, cryoablation, laser, chemicals, high-intensity focused ultrasound, etc.) to the heart tissue, creating damage to the heart tissue. This damage severs unwanted electrical pathways, thereby limiting or preventing vagal electrical signals that lead to arrhythmias.

[0005] Electroporation is a non-thermal ablation technique that involves applying a strong electric field that induces pore formation in cell membranes. The electric field can be induced, for example, by applying relatively short duration pulses that can last from nanoseconds to several milliseconds. Such pulses can be repeated to form a pulse train. When such an electric field is applied to tissue in an in vivo setting, the cells in the tissue are exposed to a transmembrane potential, which opens pores in the cell wall. Electroporation can be reversible (i.e., the temporarily opened pores reseal) or irreversible (i.e., the pores remain open), causing cell disruption. For example, in the field of gene therapy, reversible electroporation is used to introduce high molecular weight therapeutic vectors into cells. In other therapeutic applications, cell disruption can be caused by using only appropriately configured pulse trains to cause, for example, irreversible electroporation.

[0006] Catheters, such as basket catheters and planar catheters, have electrodes distributed along a set number of splines. In particular, the electrodes are typically disposed on one side of each spline. Thus, the electrode density of at least some known catheters is limited by the number of splines and the number of electrodes disposed on each spline. The electrode assembly can be limited to a set number of splines due to the inherent difficulty in increasing the number of splines. For example, with respect to basket catheters, as the number of splines increases, the diameter of the electrode basket increases, which can be undesirable as it can be more difficult to deploy to smaller target positions as the electrode basket gets larger. Alternatively, narrower splines can be used to maintain the diameter of the electrode basket, but narrower splines limit the electrode size.

[0007] In addition, when at least some known catheters are deployed, the positioning force is only applied to one side of the catheter, resulting in, for example, a spiral catheter being attached only at one point (e.g., its proximal end), so that the positioning force is only applied to one side of the spiral. Thus, it is not possible to apply a force to the opposite side (e.g., rotated 180 degrees in the helix). SUMMARY OF THE INVENTION

[0008] The present disclosure relates to a method of forming a spline for an electrode assembly for a catheter system. The method includes providing a structural member including a first surface and a second surface. The method also includes providing a flexible circuit assembly including a plurality of electrodes and at least one flexible circuit board having a contact surface and an outer surface opposite the contact surface. The plurality of electrodes are disposed on the outer surface of the at least one flexible circuit board. The method includes positioning the flexible circuit assembly relative to the structural member such that a first set of the plurality of electrodes is aligned with the first surface of the structural member and a second set of the plurality of electrodes is aligned with the second surface of the structural member. The method also includes coupling the at least one flexible circuit board to at least one of the structural member and the at least one flexible circuit board of the flexible circuit assembly.

[0009] The present disclosure further relates to an electrode assembly for a catheter system. The electrode assembly has a longitudinal axis, a proximal end, and a distal end. The electrode assembly includes at least one spline extending from the proximal end to the distal end of the electrode assembly. The at least one spline includes a structural member extending from the proximal end to the distal end of the electrode assembly. The structural member includes a first surface and a second surface. The at least one spline also includes a flexible circuit assembly including a plurality of electrodes and at least one flexible circuit board having a contact surface and an outer surface opposite the contact surface. The plurality of electrodes are disposed on the outer surface of the at least one flexible circuit board. The flexible circuit assembly is positioned with respect to the structural member such that a first set of the plurality of electrodes is aligned with the first surface of the structural member and a second set of the plurality of electrodes is aligned with the second surface of the structural member. The at least one flexible circuit board is coupled to at least one of the structural member and the at least one flexible circuit board.

[0010] The present disclosure further relates to a catheter system including a flexible catheter shaft, a handle coupled to the proximal end of the catheter shaft, and an electrode assembly. The electrode assembly is coupled to the distal end of the flexible catheter shaft and has a longitudinal axis, a proximal end, and a distal end. The electrode assembly includes at least one spline extending from the proximal end to the distal end of the electrode assembly. The at least one spline includes a structural member extending from the proximal end to the distal end of the electrode assembly. The structural member includes a first surface and a second surface. The at least one spline also includes a flexible circuit assembly including a plurality of electrodes and at least one flexible circuit board having a contact surface and an outer surface opposite the contact surface. The plurality of electrodes are disposed on the outer surface of the at least one flexible circuit board. The flexible circuit assembly is positioned with respect to the structural member such that a first set of the plurality of electrodes is aligned with the first surface of the structural member and a second set of the plurality of electrodes is aligned with the second surface of the structural member. The at least one flexible circuit board is coupled to at least one of the structural member and the at least one flexible circuit board.

Brief Description of the Drawings

[0011]

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DETAILED DESCRIPTION OF THE INVENTION

[0012] Corresponding reference numerals indicate corresponding parts throughout several views of the drawings. It is understood that the drawings are not necessarily to scale.

[0013] The present disclosure generally relates to medical devices for use in the human body. The present disclosure provides a medical device including a spline for an electrode assembly for a catheter system for use in the human vasculature for medical procedures such as mapping and / or ablation procedures, and a method of forming the spline. The electrode assembly of the present disclosure includes at least one spline including a structural member and a flexible circuit assembly. The flexible circuit assembly includes at least one flexible circuit board and a plurality of electrodes disposed on an outer surface of the at least one flexible circuit board. The flexible circuit assembly is positioned relative to the structural member such that the electrodes are aligned with both a first surface and a second surface of the structural member. At least some known electrode assemblies include a spline formed by disposing a structural member within a tubular member and subsequently disposing electrodes on an outer surface of the tubular member.

[0014] Unlike some known electrode assemblies, the disclosed embodiments enable the formation of a spline by directly coupling electrodes to one or more surfaces of a structural member via a flexible circuit board, thereby eliminating the need for an intermediate tubular member. Further, the disclosed embodiments enable the placement of electrodes on two or more surfaces of a single spline, thereby enabling the placement of more electrodes on a single spline. Such an arrangement improves the electrode density around the electrode assembly, which can improve the accuracy of mapping and / or ablation procedures and thus can result in a more consistent, improved patient outcome.

[0015] Referring now to the drawings, FIG. 1 is a schematic block diagram of a catheter system 100 suitable for diagnostic purposes, anatomical mapping and / or ablation therapy (e.g., electroporation therapy). Generally, the various embodiments include an electrode assembly disposed at the distal end of a catheter shaft. As used herein, "proximal" refers to the direction toward the end of the catheter near the clinician, and "distal" refers to the direction away from the clinician and (generally) into the body of the individual. The electrode assembly includes one or more individual electrically insulated electrode elements. Each electrode element, also referred to herein as a catheter electrode, is individually wired so as to be selectively paired or combinable with any other electrode element so as to function as a bipolar or multipolar electrode.

[0016] System 100 may be used for irreversible electroporation for tissue destruction. In particular, system 100 may be used for electroporation-induced primary necrosis therapy, which refers to the effect (result) of delivering an electric current in such a way as to directly cause an irreversible loss of the integrity of the plasma membrane (cell wall) that results in its destruction and cell death. This mechanism of cell death can be considered an "outside-in" process, meaning that the disruption of the outer wall of the cell causes harmful effects inside the cell. Typically, for classical plasma membrane electroporation, the electric current is delivered as a pulsed electric field (i.e., pulsed field ablation (PFA)) in the form of short-duration pulses (e.g., having a duration of 0.1 to 20 ms) between adjacent but separated electrodes that can deliver an electric field strength of about 0.1 to 1.0 kV / cm.

[0017] System 100 includes an electrode assembly 102 that includes at least one catheter electrode configured to be used as described below. The electrode assembly 102 is incorporated as part of a medical device such as a catheter 104 for electroporation therapy, diagnosis, mapping, and / or treatment procedures. For example, the electrode assembly 102 may be used to map one or more structures 106 within a patient's body 108, also referred to herein as internal body structures 106. As another example, the electrode assembly 102 may be used for ablation therapy (e.g., electroporation therapy) of tissue of a structure 106 within the body 108. In the illustrated embodiment, the structure 106 includes the patient's vasculature and / or the heart or heart tissue. However, it should be understood that embodiments may be used to perform mapping, diagnosis, and / or ablation therapy on a variety of other body structures and / or tissues.

[0018] System 100 also includes additional subsystems such as a visualization, navigation, and mapping system 112 for visualization, mapping, and navigation of the internal body structure 106. The power source 110 is any power source configured to apply or excite a voltage to the electrodes of the electrode assembly 102 and / or generate an electrical and / or magnetic field to perform appropriate functions during a medical procedure. For example, the power source 110 includes a radio frequency (RF) ablation and / or electroporation generator such that the system 100 can be used for RF ablation and electroporation procedures. In such embodiments, the power source 110 is configured to energize the electrodes according to an ablation strategy, which may be pre-determined or selectable by the user. When used for an RF ablation procedure, the power source 110 outputs radio frequency (RF) energy to the catheter 104 via the cable 114. The RF energy exits the catheter 104 through the electrodes of the electrode assembly 102 (e.g., using bipolar electrode stimulation). The dissipation of RF energy within the body raises the temperature near the electrodes, thereby enabling RF ablation to occur.

[0019] In some embodiments, the system 100 includes one or more return electrodes 116 (e.g., patch electrodes) for monopolar electrode stimulation or for performing a mapping function, as further described herein. In such embodiments, the power source 110 includes a signal generator coupled to the patch electrode 116 and configured to excite the patch electrode 116 to generate an electric field within the body 108.

[0020] In the illustrated embodiment, the catheter 104 includes a cable connector or interface 118, a handle 120, and a shaft 122 having a proximal end 124 and a distal end 126. The catheter 104 may also include one or more sensors (e.g., sensor 138), additional electrodes, and other conventional components not shown herein, such as corresponding conductors or lead wires. The connector 118 provides mechanical and electrical connections for the cable 114 extending from the power source 110 and / or the visualization, navigation, and mapping system 112, and is disposed at the proximal end of the catheter 104 as shown.

[0021] The handle 120 provides a location for a physician to hold the catheter 104 and may further provide means for manipulating or guiding the shaft 122 within the body 108. For example, the handle 120 may include means for changing the length of one or more guidewires that extend through the catheter 104 to the distal end 126 of the shaft 122 or to other means for manipulating the shaft 122. Further, in some embodiments, the handle 120 may be configured to change the shape, size, and / or orientation of a portion of the catheter. It will be understood that the structure of the handle 120 may vary. In an alternative exemplary embodiment, the catheter 104 may be driven or controlled by a robot. Thus, instead of a clinician operating a handle to advance / retreat and / or manipulate or guide the catheter 104 (and in particular its shaft 122), a robot is used to operate the catheter 104.

[0022] The shaft 122 is an elongated tubular flexible member configured to move within the body 108. The shaft 122 supports the electrode assembly 102 and is configured to include associated conductors and, optionally, additional electronics used for signal processing or conditioning. The shaft 122 may also enable the transport, delivery, and / or removal of fluids (including irrigation fluids and body fluids), drugs, and / or surgical tools or instruments. The shaft 122 may be made from a conventional material such as polyurethane and defines one or more lumens configured to house and / or transport conductors, fluids, or surgical tools. The shaft 122 may be introduced into a blood vessel or other structure 106 within the body 108 via a conventional introducer. The shaft 122 may then be advanced, retracted, and / or maneuvered or guided through the body 108 to a desired location within the structure 106 while using a guidewire or other means known in the art.

[0023] In embodiments of the present disclosure, the electrode assembly 102 is coupled to the distal end 126 of the shaft 122 for delivering the electrode assembly 102 to a target location within the patient's body 108. In some embodiments, the electrode assembly 102 is an electrode basket that can be selectively configured between a folded configuration and an expanded configuration. For example, the electrode assembly 102 may be delivered to the target location in a folded configuration (e.g., within the catheter shaft 122 and / or within a separate guide tube (not specifically shown)). In this example, the electrode assembly 102 is then deployed into the expanded configuration at the target location to perform a medical procedure (e.g., an ablation or mapping procedure). In some embodiments, the electrode assembly 102 is in the form of a planar or grid electrode assembly that includes paddles coupled to the catheter body. In embodiments of the present disclosure, the electrode assembly 102 is then energized using the power source 110 to perform a medical procedure at the target location. The electrode assembly 102 may include a plurality of electrodes (e.g., the electrodes 226 shown in FIGS. 3-5) thereon. The electrode assembly 102 and / or the catheter shaft 122 may include one or more sensors 138 therein or thereon.

[0024] The sensors 138 mounted within or on the shaft 122 and / or within or on the electrode assembly 102 may be provided for various diagnostic and therapeutic purposes, including, for example, electrophysiological studies and cardiac mapping. In an exemplary embodiment, one or more of the sensors 138 are provided to perform a position sensing function. More specifically, one or more of the sensors 138 are configured to provide information regarding the location (e.g., position and orientation) of the catheter 104 and its distal end 126 at a particular point in time, for example, to a visualization, navigation, and mapping system 112. The sensors 138 may comprise one of several types of sensors, such as, but not limited to, electrodes (e.g., chip electrodes and ring electrodes) or magnetic sensors (e.g., magnetic coils). It will be understood that the number, shape, orientation, and purpose of the sensors may vary.

[0025] The visualization, navigation, and mapping system 112 may be provided for visualization, mapping, and navigation of internal body structures 106, for example, by determining the electrode assemblies 102 thereon, one or more splines, and / or the positions of specific electrodes. These positions may be projected onto a geometric anatomical model. The visualization, navigation, and mapping system 112 may include conventional devices generally known in the art (e.g., the EnSite™ Velocity™ or EnSite™ Precision™ cardiac mapping and visualization systems of Abbott Laboratories, or the EnSite™ NavX™ system commercially available from Abbott Laboratories and generally shown as in U.S. Patent No. 7,263,397, "Method and Apparatus for Catheter Navigation and Location and Mapping in the Heart", the entire disclosure of which is incorporated herein by reference.). Other systems and components suitable for use with the visualization, navigation, and mapping system 112 are described, for example, in U.S. Patent No. 7,885,707, entitled "Method of Scaling Navigation Signals to Account for Impedance Drift in Tissue", and U.S. Patent Application Publication No. 2018 / 0296111, entitled "Orientation Independent Sensing, Mapping, Interface and Analysis System and Methods", the entire disclosures of which are incorporated herein by reference. In various embodiments, the visualization, navigation, and mapping system 112 uses the electrodes of the electrode assembly 102 as a bipolar pair for visualization, mapping, and navigation of the internal body structure 106. However, it should be understood that this system is merely exemplary and not inherently limiting.For example, other techniques for visualizing / navigating / mapping a catheter within a space are known, such as, for example, generally available fluoroscopy systems such as the CARTO navigation and location system of Biosense Webster, Inc., the AURORA® system of Northern Digital Inc., or magnetic location systems such as the gMPS system from MediGuide Ltd. In this regard, some of the location, navigation, and / or visualization systems will provide a sensor for generating a signal indicative of catheter position information, for example, including one or more electrodes in the case of an impedance-based location system, or one or more coils (i.e., wire windings) configured to detect one or more characteristics of a magnetic field in the case of, for example, a magnetic field-based location system.

[0026] System 100 may further include a main computer system 130 that may be integrated with a visualization, navigation, and mapping system 112 in certain embodiments. The computer system 130 may include an electronic control unit (ECU) 132 and a memory 134. The computer system 130 may further include a display device 136, which may be integrated with and / or coupled to the computer system 130. The catheter 104, and thus the electrode assembly 102, may be coupled to the computer system 130 and / or the visualization, navigation, and mapping system 112 using a wired or wireless connection.

[0027] FIG. 2 is a simplified schematic diagram of the visualization, navigation, and / or mapping system 112 of system 100 (shown in FIG. 1). Referring to FIGS. 1 and 2, the visualization, navigation, and mapping system 112 may include, among other components, a plurality of patch electrodes 116, an ECU 132, and a display device 136. A patch electrode 116 referred to as a “belly patch”B Except for the catheter 104, the patch electrodes 116 are provided to generate signals that are used, for example, in determining the position and orientation of, and guiding, the catheter 104. In one embodiment, the patch electrodes 116 are positioned orthogonally on the surface of the patient's body 108 and are used to generate axis-specific electric fields within the body 108. For example, in one exemplary embodiment, the patch electrodes 116 X1 , 116 X2 may be arranged along the first (x) axis. Y1 , 116 Y2 may be disposed along the second (y) axis, and the patch electrode 116 Z1 , 116 Z2 may be disposed along the third (z) axis. In other embodiments, the dipole generated may not be on one axis, for example, electrode 116 X1 and 116 Y1 The patch electrodes 116 may be dipoles between the body 108 and the patient's heart. Each of the patch electrodes 116 may be coupled to a multiplex switch 140. In an exemplary embodiment, the ECU 132 is configured to provide a control signal to the switch 140 via suitable software to sequentially couple pairs of the electrodes 116 to a signal generator (e.g., the power supply 110). Excitation of each pair of the electrodes 116 generates an electric field within the body 108 and within a region of interest, such as the patient's heart. The berry patch 116 B The potential of the non-excited electrode 116 relative to the reference may be filtered, for example, by a low pass filter 142, converted by an analog to digital converter 144, and provided to the ECU 132 for use as a reference.

[0028] As described above, the catheter 104 includes the electrode assembly 102 coupled thereto. In an exemplary embodiment, the electrode assembly 102 includes a plurality of splines, each spline including one or more electrodes (e.g., electrode 414 shown in FIGS. 5 - 13) mounted therein or thereon, and in some embodiments, these plurality of electrodes are electrically connected to the power supply 110 and / or the ECU 132 to provide one or more diagnostic or therapeutic purposes as described herein. In an exemplary embodiment, the electrode assembly 102 is disposed within the electric field generated within the body 108 by exciting the patch electrodes 116. When disposed within the electric field, the electrodes on the electrode assembly 102 receive voltages that depend on their positions between the patch electrodes 116 and the positions of each electrode relative to the tissue of the anatomical structure 106 being mapped. By using the comparison of the voltage measurements made between each electrode on the electrode assembly 102 and the patch electrodes 116, the position of each electrode on the electrode assembly 102 relative to the anatomical structure 106 can be determined. This position information may then be used by the ECU 132 to generate a model, such as a surface model and / or map of the anatomical structure, or a model corresponding to the anatomical structure. Thus, when moving the catheter 104 along the surface of the desired anatomical structure 106, for example, the electrode assembly 102 can be used to collect the positions of the electrodes thereon, and thus the position data points corresponding to the surface of the anatomical structure 106. These position data points can then be used by the ECU 132 to generate or construct, for example, a surface model of the anatomical structure. Additionally, the information received from the electrode assembly 102 can also be used to display the position and orientation of the electrode assembly 102 and / or the tip of the catheter 104 on a display device, such as the display device 136. Thus, among other things, the ECU 132 of the visualization, navigation, and mapping system 112 generates a display signal used to control the display device 136 and provides means for creating a graphical user interface (GUI) on the display device 136.

[0029] ECU 132 may include, for example, a programmable microprocessor or microcontroller, or may include an application specific integrated circuit (ASIC). ECU 132 may include a central processing unit (CPU) and an input / output (I / O) interface, through which ECU 132 may receive a plurality of input signals including, for example, signals generated by the electrode assembly 102. ECU 132 may generate a plurality of output signals including, for example, output signals used to control the display device 136. ECU 132 may be configured to perform various functions such as those described herein using appropriate programming instructions or code. Thus, in one embodiment, ECU 132 is programmed with one or more computer programs encoded on a computer-readable storage medium to perform the functions described herein.

[0030] ECU 132 may be configured to construct a geometric anatomical model of the structure 106 for display on the display device 136. ECU 132 may also be configured to generate a graphical user interface (GUI), through which the user may view, among other things, the geometric anatomical model and / or the control electrode assembly 102. The anatomical model may include a 3D model or a two-dimensional (2D) model. To display the data and images generated by ECU 132, the display device 136 may include one or more conventional computer monitors or other display devices well known in the art.

[0031] FIG. 3 is a perspective view of an exemplary electrode assembly 102 suitable for use in system 100, shown in the form of a basket electrode assembly 200. The basket electrode assembly 200 includes a basket 202 coupled to a catheter body 204 (e.g., shaft 122) by a suitable proximal connector 206. The basket 202 includes a plurality of splines 208 and a distal coupler 210 at which each of the splines 208 terminates. In some embodiments, such as the illustrated embodiment, the basket electrode assembly 200 may also include an irrigation tube 212 (e.g., to supply fluid to the basket electrode assembly 200). In other embodiments, the irrigation tube 212 may be omitted. Each of the plurality of splines 208 includes at least one electrode 214. In the illustrated embodiment, each of the plurality of splines includes eight electrodes 214, although each spline 208 may include more or fewer than eight electrodes 214.

[0032] Electrode 214 may be used for various diagnostic and therapeutic purposes, including, but not limited to, cardiac mapping and / or ablation (e.g., RF ablation or irreversible electroporation (IRE) ablation). For example, in some embodiments, electrode assembly 200 may be configured as a bipolar electrode assembly for use in bipolar-based electroporation therapy. Specifically, electrode 214 may be individually electrically coupled (e.g., via a suitable wire or other suitable conductor extending through catheter shaft 122) to an electroporation generator such as power source 110 and configured to be selectively energized (e.g., by power source 110 and / or computer system 130) with opposite polarities to generate a potential and corresponding electric field therebetween for IRE therapy. That is, one of electrodes 214 may be configured to function as a cathode and another one of electrodes 214 may be configured to function as an anode. Electrode 214 may be any suitable electroporation electrode. Electrode 214 may have any other shape or configuration. It is understood that the shape, size, and / or configuration of electrode 214 may affect various parameters of the applied electroporation therapy. For example, increasing the surface area of one or more electrodes 214 may reduce the applied voltage required to cause the same level of tissue disruption. In various embodiments, any combination of electrodes 214 may be configured as an electrode pair, including, but not limited to, adjacent electrodes, non-adjacent electrodes, electrodes on adjacent splines, electrodes on non-adjacent splines, and any other combination of electrodes that enables system 100 to function as described herein. In some embodiments, power source 110 is configured to energize the electrodes according to an ablation strategy as described above.

[0033] FIG. 4 is a perspective view of another exemplary electrode assembly 102 suitable for use in system 100, shown in the form of a planar electrode assembly 300. The planar electrode assembly 300 includes paddles 302 coupled to a catheter body 304 (e.g., shaft 122). In the illustrated embodiment, the catheter body 304 includes body electrodes 306, 308, 310 coupled thereto. In the illustrated embodiment, the paddle 302 includes a first spline 312, a second spline 314, a third spline 316, and a fourth spline 318, which are coupled to the catheter body 304 by a proximal coupler and to each other by a distal connector at the distal end of the paddle 302. In one embodiment, the first spline 312 and the fourth spline 318 can be one continuous segment, and the second spline 314 and the third spline 316 can be another continuous segment. In other embodiments, the various splines can be separate segments coupled to each other. The first spline 312, the second spline 314, the third spline 316, and the fourth spline 318 are generally aligned in the same (phase) plane. The paddle 302 is shown as being relatively flat or planar in FIG. 4, but it should be understood that the paddle 302 can be bent, curled, kinked, twisted, and / or otherwise deformed. Thus, the plane defined by the paddle 302 and the splines 312, 314, 316, 318 can correspondingly deform such that the plane is a non-flat phase plane. In the illustrated embodiment, the planar electrode assembly 300 also includes an irrigation port 320 at the distal end of the catheter body 304. The irrigation port 320 is arranged to deliver an irrigant to a portion of one or more of the splines 312-318.

[0034] The plurality of splines can further include various numbers of electrodes 322. The electrodes in the illustrated embodiment can include single-sided electrodes or electrodes printed on a flexible bendable material. The electrodes may be evenly spaced along one or more surfaces of the spline. In other embodiments, the electrodes can be spaced evenly or unevenly, and the electrodes can include any other suitable type of electrode.

[0035] The electrodes 322 may be used for various diagnostic and therapeutic purposes, including, for example, but not limited to, cardiac mapping and / or ablation (e.g., RF ablation or IRE ablation). For example, in some embodiments, the electrode assembly 300 may be configured as a bipolar electrode assembly for use in bipolar-based electroporation therapy. Specifically, the electrodes 322 may be individually electrically coupled (e.g., via a suitable wire or other suitable conductor extending through the catheter shaft 122) to an electroporation generator such as the power source 110, and for IRE therapy, configured to be selectively energized (e.g., by the power source 110 and / or the computer system 130) with opposite polarities to generate a potential and corresponding electric field therebetween. That is, one of the electrodes 322 may be configured to function as a cathode, and another one of the electrodes 322 may be configured to function as an anode. The electrodes 322 may be any suitable electroporation electrodes. The electrodes 322 may have any other shape or configuration. It is understood that the shape, size, and / or configuration of the electrodes 322 can affect various parameters of the applied electroporation therapy.

[0036] FIG. 5 shows an end view of an exemplary spline 400 suitable for use in the electrode assemblies (e.g., electrode assemblies 102, 200, 300) described herein. In particular, the spline 400 may be incorporated as one or more splines 208 (both shown in FIG. 3) into the basket electrode assembly 200. Additionally or alternatively, the spline 400 may be incorporated as one or more splines 312, 314, 316, 318 (all shown in FIG. 4) into the planar electrode assembly 300. In the illustrated embodiment, the spline 400 includes a flexible circuit assembly 402 and a structural member 404. The structural member 404 extends from the proximal end 401 of the spline 400 to a distal end (not shown in FIG. 5) and generally provides structural support to the spline 400 and its components (e.g., the flexible circuit assembly 402). The structural member 404 includes a first surface 406 and a second surface 408 (both shown in FIG. 7). In the illustrated embodiment, the structural member 404 has a rectangular cross-section, and the first surface 406 and the second surface 408 are located on opposite sides of the structural member 404. In other embodiments, the structural member 404 may have a cross-sectional shape other than rectangular, and the first surface 406 and the second surface 408 may be on sides of the structural member 404 that do not face each other. Further, in an exemplary embodiment, the structural member 404 is a single continuous member that extends along the entire length of the spline 400 (i.e., from the proximal end 401 to the distal end).

[0037] The structural member 404 may be constructed from a variety of suitable materials including, for example, but not limited to, metal alloys, stainless steel, copper-aluminum-nickel alloys, zinc, copper, gold, and / or alloys containing any of the foregoing materials, polymers containing any of the foregoing materials, shape memory polymers, and / or combinations thereof. In some embodiments, the structural member 404 may be constructed from a non-metallic material such as, for example, a formed rigid plastic material. In an exemplary embodiment, the structural member 404 is composed of a shape memory alloy. One particularly preferred shape memory alloy for use is nitinol, a nickel-titanium (NiTi) alloy. Nitinol is a nearly stoichiometric alloy of nickel and titanium and may contain small amounts of other metals to achieve desired properties. Nickel-titanium alloys are highly elastic and are generally referred to as "superelastic" or "pseudoelastic." Such memory shape alloys tend to have a temperature-induced phase change that provides the material with a preferred configuration that can be fixed by heating the material above a specific transition temperature to induce a phase change in the material. When the alloy is cooled back, the alloy "remembers" the shape it had during the heat treatment and tends to assume that shape unless constrained.

[0038] The flexible circuit assembly 402 includes at least one flexible circuit designed to bend or flex during use and is typically mounted on a flexible substrate. In the illustrated embodiment, the flexible circuit assembly 402 includes a first subassembly 410 and a second subassembly 412. FIG. 6 is a top view of each of the first and second subassemblies of the flexible circuit assembly 402 (shown in FIG. 5). In the illustrated embodiment, the first subassembly 410 and the second subassembly 412 are identical, but in other embodiments, the first subassembly 410 and the second subassembly 412 may have different configurations. Referring to FIGS. 5 and 6, each of the first subassembly 410 and the second subassembly 412 includes a plurality of electrodes 414 disposed on a flexible circuit board 416. Each flexible circuit board 416 of the subassemblies 410, 412 includes an outer surface 418 opposite a contact surface (e.g., an inner surface) 420 (shown in FIG. 7). Each flexible circuit board 416 also includes a first longitudinal edge 422 and a second longitudinal edge 424. In one embodiment, the flexible circuit board 416 is a flexible printed circuit such as a polyimide flexible circuit. In one example, the flexible circuit board 416 may be a Kapton® polyimide flexible circuit.

[0039] The electrode 414 is disposed on the outer surface 418 of each flexible circuit board 416. The electrode 414 may be any suitable type of electrode, such as a single-sided electrode disposed on the outer surface 418 or an electrode printed on the flexible circuit board 416. In an exemplary embodiment, the first subassembly 410 and the second subassembly 412 each include a single flexible circuit including electrodes on one side of the flexible circuit. The illustrated embodiment includes 12 electrodes disposed on the outer surface 418, although other embodiments may include more or fewer electrodes than 12. For example, the first subassembly 410 and the second subassembly 412 may include any suitable number of electrodes that enable the system 100 to function as described herein. In one example, the spline 400 may include from 8 to 12 electrodes on each of the subassemblies 410, 412. Further, the electrode 414 is rectangular or pseudo-rectangular (i.e., a rounded rectangle) in the illustrated embodiment. In other embodiments, the electrode 414 may have any suitable shape or configuration that enables the spline 400 to function as described herein, and may include, for example, but not limited to, a rounded shape or a spherical shape. The plurality of electrodes 414 of the first subassembly 410 may be interchangeably referred to herein as the "first electrode set," and the plurality of electrodes 414 of the second subassembly 412 may be interchangeably referred to herein as the "second electrode set."

[0040] FIG. 7 shows step 500 in an exemplary method of forming spline 400 (shown in FIG. 5). Referring to FIGS. 5-7, an exemplary method of forming spline 400 includes positioning structural member 404 between first sub-assembly 410 and second sub-assembly 412 such that electrodes 414 (e.g., first electrode set) of first sub-assembly 410 are aligned with first surface 406 of structural member 404 and electrodes 414 (e.g., second electrode set) of second sub-assembly 412 are aligned with second surface 408 of structural member 404. The exemplary method further includes coupling flexible circuit boards 416 to each other at respective first edges 422 and respective second edges 424, as indicated by arrow 426 in FIG. 7. Flexible circuit boards 416 may be coupled at respective first edges 422 and respective second edges 424 using an adhesive material 428 (shown in FIG. 5). In one embodiment, an opening (e.g., a space gap) formed by coupling respective first edges 422 and respective second edges 424 may be completely filled with adhesive material 428. Adhesive material 428 may be applied on one or both contact surfaces 420 of flexible circuit boards 416. Adhesive material 428 may be a biocompatible adhesive or any suitable material for adhering flexible circuit boards 416 together.

[0041] In other embodiments, the flexible circuit boards 416 are heat-sealed together. In some embodiments, the flexible circuit boards 416 are coupled only to each other and not fixed to the structural member 404. For example, the flexible circuit boards 416 of the first subassembly 410 and the second subassembly 412 may be coupled only at their respective first edges 422 and second edges 424 such that the coupled flexible circuit boards 416 are free to move and slide relative to the structural member 404. In other embodiments, one or both of the flexible circuit boards 416 are directly coupled to the structural member 404 at the first surface 406 and / or the second surface 408. In an exemplary embodiment, the structural member 404 is sandwiched between two separate subassemblies 410, 412 to form a double-sided spline of the electrodes 414.

[0042] FIG. 8 shows an end view of another exemplary spline 600 suitable for use in the electrode assembly 102 (shown in FIG. 1). In particular, the spline 600 may be incorporated as one or more of the splines 208 into the basket electrode assembly 200 (both shown in FIG. 3). Additionally or alternatively, the spline 600 may be incorporated as one or more of the splines 312, 314, 316, 318 (all shown in FIG. 4) into the planar electrode assembly 300. The spline 600 may be substantially similar to the spline 400 as described above, or may have a substantially similar configuration. The spline 600 includes a structural member 404 and a flexible circuit assembly 602. The structural member 404 extends from the proximal end 601 to the distal end (not shown) of the spline 600. The flexible circuit boards 416 may be coupled to each other using an adhesive material 428. In one embodiment, the opening (e.g., the space gap) formed by coupling the flexible circuit boards 416 may be completely filled with the adhesive material 428.

[0043] FIG. 9 is a top view of the flexible circuit assembly 602 of the spline 600 (shown in FIG. 8). Referring to FIGS. 8 and 9, the flexible circuit assembly 602 includes a first subassembly 410 and a second subassembly 412. Each of the subassemblies 410, 412 includes a plurality of electrodes 414 disposed on the outer surface 418 of the flexible circuit board 416. In the embodiment shown in FIGS. 8 and 9, the first subassembly 410 and the second subassembly 412 of the flexible circuit assembly 602 are joined to each other by a fold line 604. The fold line 604 may include any weak line that facilitates folding or bending of the subassemblies 410, 412 joined by the fold line 604, such as, for example, a cut line, a break line, a crease, a perforation line, and combinations thereof.

[0044] FIG. 10 shows step 700 in an exemplary method of forming spline 600 (shown in FIG. 8) using flexible circuit assembly 602. As shown in FIG. 10, an exemplary method of forming spline 600 includes positioning structural member 404 adjacent both subassemblies 410, 412 near contact surface 420 such that structural member 404 is close to fold line 604. FIG. 11 shows another subsequent step 800 in an exemplary method of forming spline 600. As shown in FIG. 11, an exemplary method of forming spline 600 also includes folding flexible circuit assembly 602 at fold line 604 and around structural member 404 such that electrodes 414 (e.g., a first set of electrodes) of the first subassembly 410 are coupled proximate to a first surface 406 of structural member 404 and electrodes 414 (e.g., a second set of electrodes) of the second subassembly 412 are coupled proximate to a second surface 408 of structural member 404. An exemplary method of forming spline 600 also includes coupling flexible circuit boards 416 of subassemblies 410, 412 to each other at longitudinal edge 606 of flexible circuit assembly 602, as indicated by arrow 608 in FIG. 10. As shown in FIG. 8, flexible circuit boards 416 may be coupled at edge 606 using adhesive material 428. In some embodiments, flexible circuit boards 416 of the first subassembly 410 and the second subassembly 412 are coupled only to each other and not fixed to structural member 404. For example, flexible circuit boards 416 of the first and second subassemblies 410, 412 may be coupled only at longitudinal edge 606 such that the coupled flexible circuit boards 416 are free to move and slide relative to structural member 404. In other embodiments, one or both of flexible circuit boards 416 are directly coupled to structural member 404 at first surface 406 and / or second surface 408.

[0045] FIG. 12 shows an end view of another exemplary spline 900 suitable for use in the electrode assembly 102 (shown in FIG. 1). In particular, the spline 900 may be incorporated as one or more of the splines 208 into the basket electrode assembly 200 (both shown in FIG. 3). Additionally or alternatively, the spline 900 may be incorporated as one or more of the splines 312, 314, 316, 318 (all shown in FIG. 4) into the planar electrode assembly 300. The spline 900 includes a structural member 404 and a flexible circuit assembly 902. The structural member 404 has been described above with respect to the spline 400 (shown in FIG. 5) and the spline 600 (shown in FIG. 8). FIG. 13 shows step 1000 in an exemplary method of forming the spline 900 (shown in FIG. 12). Referring to FIGS. 12 and 13, the flexible circuit assembly 902 of the spline 900 includes a flexible tubular substrate 904 that defines a cavity 906 therein. In one embodiment, the flexible tubular substrate 904 is a flexible printed circuit formed in the shape of a compressible cylindrical tube.

[0046] A plurality of electrodes 414 are disposed on the outer surface 908 of the flexible tubular substrate 904. The electrodes 414 may have the same configuration as described above with reference to the spline 400 (shown in FIG. 5) and the spline 600 (shown in FIG. 8). The flexible circuit assembly 902 includes two sets (a first set and a second set) of electrodes 414 disposed on both sides of the flexible tubular substrate 904. Each set of electrodes 414 may include any suitable number of electrodes 414 that enables the spline 900 to function as described herein. For example, each set of electrodes 414 may include from 8 to 12 electrodes.

[0047] As shown in FIG. 13, an exemplary method of forming a spline 900 includes inserting a structural member 404 into a cavity 906 of a flexible tubular substrate 904. The exemplary method of forming a spline 900 further includes compressing the flexible tubular substrate 904 (e.g., by applying a force to the outer surface 908) such that a first set of electrodes 414 of the flexible circuit assembly 902 is coupled proximate to a first surface 406 of the structural member 404 and a second set of electrodes 414 of the flexible circuit assembly 902 is coupled proximate to a second surface 408 of the structural member 404. An adhesive material 428 may be applied onto a contact surface (e.g., inner surface) 910 of the flexible tubular substrate 904, and when the flexible tubular substrate 904 is compressed, the contact surface 910 of the flexible tubular substrate 904 adheres to the structural member 404. In one embodiment, an opening (e.g., a space gap) formed by compressing the flexible tubular substrate 904 may be completely filled with the adhesive material 428.

[0048] The splines and spline forming methods of the present disclosure are described with reference to particular electrode assemblies (e.g., the basket electrode assembly 200 and the planar electrode assembly 300), but it should be understood that the disclosed splines and spline forming methods are not limited to use in the particular electrode assembly structures shown and described herein and may be incorporated into any other suitable electrode assembly that enables the system 100 (shown in FIG. 1) to function as described herein.

[0049] FIG. 14 is a perspective view of one of the sub-assemblies 410, 412 disposed in the helical configuration 1100 suitable for use in the system 100 (shown in FIG. 1). In the illustrated embodiment, the structural member 404 is omitted. In other embodiments, the individual sub-assemblies 410, 412 may be coupled to a structural member such as the structural member 404 to facilitate, for example, deployment of the individual sub-assemblies 410, 412 into a desired helical shape or other desired shape to facilitate contact with a particular anatomical structure. The individual sub-assemblies 410, 412 are wound along the length of the sub-assemblies 410, 412 to form the helical configuration 1100 and are lengthened to reduce the outer diameter of the helical configuration 1100. More specifically, in these embodiments, the flexible circuit board 416 of one of the sub-assemblies 410, 412 may be coiled and extended for insertion as one long linear catheter within the system 100. In the illustrated embodiment, the electrodes 414 are disposed on the outer surface 418 of the flexible circuit board 416. The electrodes 414 may be any suitable type of electrode, such as a single-sided electrode disposed on the outer surface 418 or an electrode printed on the flexible circuit board 416. In some embodiments, the individual sub-assemblies 410, 412 including the structural member 404 may be wound in a helical configuration.

[0050] FIG. 15 is a flowchart of an exemplary method 1200 of forming a spline, such as spline 400 (shown in FIG. 5), spline 600 (shown in FIG. 8), or spline 900 (shown in FIG. 12), for use in an electrode assembly (e.g., electrode assembly 102 shown in FIG. 1). Method 1200 includes providing a structural member (e.g., structural member 404) that includes a first surface and a second surface 1202. Method 1200 also includes providing a flexible circuit assembly (e.g., flexible circuit assembly 402, flexible circuit assembly 602, or flexible circuit assembly 902) that includes a plurality of electrodes and at least one flexible circuit board (e.g., flexible circuit board 416 or flexible tubular substrate 904). The at least one flexible circuit board includes a contact surface and an outer surface opposite the contact surface. The plurality of electrodes are disposed on the outer surface of the at least one flexible circuit board. Method 1200 also includes positioning the flexible circuit assembly relative to the structural member such that a first set of the plurality of electrodes is aligned with the first surface of the structural member and a second set of the plurality of electrodes is aligned with the second surface of the structural member 1206. Method 1200 also includes coupling the at least one flexible circuit board to the structural member and to at least one of the at least one flexible circuit board 1208.

[0051] Some of the steps of the exemplary method are numbered, but such numbering does not indicate that the steps must be performed in the order in which they are listed. Thus, a particular step need not be performed in the exact order in which it is presented, unless the description of that step specifically requires such an order. The steps may be performed in the order listed or in another appropriate order.

[0052] The embodiments and examples disclosed in this specification are described with reference to specific embodiments, but it should be understood that these embodiments and examples are merely illustrative of the principles and applications of the present disclosure. Therefore, it should be understood that many changes can be made to the exemplary embodiments and examples without departing from the spirit and scope of the present disclosure defined by the claims, and other configurations can be devised. Therefore, this application is intended to cover modifications and variations of these embodiments and their equivalents.

[0053] This specification uses examples to disclose the present invention, including the best mode, and enables any person skilled in the art to practice the present disclosure, including making and using any device or system and performing any incorporated method. The patentable scope of the present disclosure is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are considered to be within the scope of the claims if the components are not different from those described in the claims or include equivalent components that are not significantly different from those described in the claims.

Claims

1. 1. A method of forming a spline for an electrode assembly for a catheter system, comprising: Providing a structural member including a first surface and a second surface; providing a flexible circuit assembly including a plurality of electrodes and at least one flexible circuit board having a contact surface and an outer surface opposite the contact surface, the plurality of electrodes being disposed on the outer surface of the at least one flexible circuit board; positioning the flexible circuit assembly relative to the structural member such that a first electrode set of the plurality of electrodes is aligned with the first surface of the structural member and a second electrode set of the plurality of electrodes is aligned with the second surface of the structural member; and bonding the at least one flexible circuit board to at least one of the structural member and the at least one flexible circuit board of the flexible circuit assembly.

2. 10. The method of claim 1, wherein coupling the at least one flexible circuit board to at least one of the structural member and the at least one flexible circuit board comprises coupling the at least one flexible circuit board to the structural member using an adhesive.

3. 3. The method of claim 2, wherein coupling the at least one flexible circuit board to the structural member comprises coupling the contact surface of the at least one flexible circuit board to at least one of the first surface and the second surface of the structural member using the adhesive.

4. 2. The method of claim 1, wherein coupling the at least one flexible circuit board to at least one of the structural member and the at least one flexible circuit board comprises heat fusing the at least one flexible circuit board to the at least one of the structural member and the at least one flexible circuit board.

5. the at least one flexible circuit board includes a first flexible circuit board and a separate second flexible circuit board; each of the first flexible circuit board and the second flexible circuit board includes a first longitudinal edge and a second longitudinal edge; positioning the flexible circuit assembly relative to the structural member comprises positioning the structural member between the first flexible circuit board and the second flexible circuit board; 2. The method of claim 1 , wherein bonding the at least one flexible circuit board to at least one of the structural member and the at least one flexible circuit board comprises bonding the first flexible circuit board and the second flexible circuit board at their respective first longitudinal edges and their respective second longitudinal edges such that the first electrode set of the plurality of electrodes is aligned with the first surface of the structural member and the second electrode set of the plurality of electrodes is aligned with the second surface of the structural member.

6. 6. The method of claim 5, wherein bonding the first flexible circuit board and the second flexible circuit board at the respective first edges and the respective second edges comprises bonding the first flexible circuit board and the second flexible circuit board using an adhesive such that the first flexible circuit board and the second flexible circuit board are slidable relative to the structural member.

7. the flexible circuit assembly includes a first flexible circuit board and a second flexible circuit board joined to the first flexible circuit board at a fold line; 2. The method of claim 1 , wherein forming the splines comprises folding the first flexible circuit board at the fold lines relative to the second flexible circuit board and around the structural member such that the first electrode set is aligned with the first surface of the structural member and the second electrode set is aligned with the second surface of the structural member.

8. 8. The method of claim 7, wherein bonding the at least one flexible circuit board to at least one of the structural member and the at least one flexible circuit board comprises bonding the first flexible circuit board to the second flexible circuit board using an adhesive.

9. the at least one flexible circuit substrate of the flexible circuit assembly comprises a tubular substrate defining a cavity therein; The method of claim 1 , wherein positioning the flexible circuit assembly relative to the structural member comprises inserting the structural member into the cavity of the tubular substrate.

10. 10. The method of claim 9, wherein positioning the flexible circuit assembly relative to the structural member further comprises compressing the tubular substrate such that the first electrode set is aligned with the first surface of the structural member and the second electrode set is aligned with the second surface of the structural member.

11. The method of claim 1 , wherein the structural member is comprised of Nitinol.

12. The method of claim 1 , wherein the at least one flexible circuit board is a flexible printed circuit.

13. The method of claim 1 , wherein the structural member comprises a plurality of separate members.

14. The method of claim 1 , further comprising incorporating the formed splines into a planar electrode assembly.

15. The method of claim 1 , further comprising incorporating the formed splines into a basket electrode assembly.

16. The method of claim 1 , further comprising wrapping the at least one flexible circuit board around a length of the at least one flexible circuit board to form a spiral configuration.

17. 1. An electrode assembly for a catheter system, comprising: the electrode assembly having a longitudinal axis, a proximal end, and a distal end; the electrode assembly comprising at least one spline extending from the proximal end to the distal end of the electrode assembly; The at least one spline is a structural member extending from the proximal end to the distal end of the electrode assembly and including a first surface and a second surface; a flexible circuit assembly including a plurality of electrodes and at least one flexible circuit board having a contact surface and an outer surface opposite the contact surface, the plurality of electrodes being disposed on the outer surface of the at least one flexible circuit board; the flexible circuit assembly is positioned relative to the structural member such that a first set of electrodes of the plurality of electrodes is aligned with the first surface of the structural member and a second set of electrodes of the plurality of electrodes is aligned with the second surface of the structural member; The at least one flexible circuit board is coupled to at least one of the structural member and the at least one flexible circuit board.

18. The flexible circuit assembly includes a first flexible circuit board and a separate second flexible circuit board; each of the first flexible circuit board and the second flexible circuit board includes a first longitudinal edge and a second longitudinal edge; the structural member is disposed between the first flexible circuit board and the second flexible circuit board; 18. The electrode assembly of claim 17, wherein the first flexible circuit board and the second flexible circuit board are joined at the first longitudinal edge and the second longitudinal edge, respectively, such that the first electrode set of the plurality of electrodes is aligned with the first surface of the structural member and the second electrode set of the plurality of electrodes is aligned with the second surface of the structural member.

19. The flexible circuit assembly includes at least two flexible circuit boards joined at fold lines; 18. The electrode assembly of claim 17, wherein the flexible circuit assembly is folded at the fold lines and around the structural member such that the first electrode set is aligned with the first surface of the structural member and the second electrode set is aligned with the second surface of the structural member.

20. 1. A catheter system comprising: A flexible catheter shaft; a handle coupled to a proximal end of the catheter shaft; an electrode assembly coupled to a distal end of the flexible catheter shaft, the electrode assembly having a longitudinal axis, a proximal end, and a distal end, the electrode assembly comprising at least one spline extending from the proximal end to the distal end of the electrode assembly; The at least one spline is a structural member extending from the proximal end to the distal end of the electrode assembly and including a first surface and a second surface; a flexible circuit assembly including a plurality of electrodes and at least one flexible circuit board having a contact surface and an outer surface opposite the contact surface, the plurality of electrodes being disposed on the outer surface of the at least one flexible circuit board; the flexible circuit assembly is positioned relative to the structural member such that a first set of electrodes of the plurality of electrodes is aligned with the first surface of the structural member and a second set of electrodes of the plurality of electrodes is aligned with the second surface of the structural member; The at least one flexible circuit board is coupled to at least one of the structural member and the at least one flexible circuit board.

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