SYSTEMS AND METHODS FOR COUPLING SEGMENTED SPINE STRUTS

The disclosed technology includes a segmented spine comprising a first electrode, a first spine strut, and a second spine strut. The first spine strut comprises a first attachment point configured to couple with the first electrode. The second spine strut comprises a second attachment point configured to couple with the first electrode. The first spine strut and second spine strut can comprise of additional attachment points configured to engage with a distal retention hub or a tubular shaft. The attachment points can be configured to permit the plurality of spine struts to rotate around the respective attachment points.

FIELD

The present invention relates generally to medical devices, and in particular catheters with electrodes, and further relates to, but not exclusively, the coupling of a plurality of segmented spine struts to electrodes at attachment points.

BACKGROUND

Cardiac arrhythmias, such as atrial fibrillation (AF), occur when regions of cardiac tissue abnormally conduct electric signals to adjacent tissue. This disrupts the normal cardiac cycle and causes asynchronous rhythm. Certain procedures exist for treating arrhythmia, including surgically disrupting the origin of the signals causing the arrhythmia and disrupting the conducting pathway for such signals. By selectively ablating cardiac tissue by application of energy via a catheter, it is sometimes possible to cease or modify the propagation of unwanted electrical signals from one portion of the heart to another. Medical probes may utilize radiofrequency (RF) electrical energy to heat tissue. Some ablation approaches use irreversible electroporation (IRE) to ablate cardiac tissue using nonthermal ablation methods.

Regions of cardiac tissue can be mapped by a catheter to identify the abnormal electrical signals. The same or different catheter can be used to perform ablation. Some example catheters include a number of spines with electrodes positioned thereon. The electrodes are generally attached to the spines and secured in place by soldering, welding, or using an adhesive. Furthermore, multiple linear spines are generally assembled together by attaching both ends of the linear spines to a tubular shaft (e.g., a pusher tube) to form a spherical basket. Due to the small size of the spines and the electrodes, however, adhering the electrodes to the spines and then forming a spherical basket from the multiple linear spines can be a difficult task, increasing the manufacturing time and cost and the chances that the electrode fails due to an improper bond or misalignment. What is needed, therefore, are devices and methods of forming an improved basket assembly that can help to reduce the time required for manufacturing the basket assembly and alternative basket assembly geometries in general.

SUMMARY

Various embodiments of a medical probe and related methods are described and illustrated. The medical probe may include a tubular shaft and an expandable basket assembly. The tubular shaft can have a proximal end and a distal end. The tubular shaft extends along a longitudinal axis. The expandable basket assembly can be positioned proximate the distal end of the tubular shaft. The basket assembly can include a structure that includes spine sections and a central spine intersection, a loop retention hub, and one or more electrodes. The central spine intersection can be positioned on the longitudinal axis at a distal end of the basket assembly. Each spine section can have at least one end connected to the distal end of the tubular shaft. The loop retention hub can include a first portion and a second portion configured to mate with each other to retain a distal portion of each of the spine sections at the central spine intersection. The electrode(s) can be coupled to each of the spine sections. Each electrode can define a lumen through the electrode so that a spine section extends through the lumen of each of the one or more electrodes. The spine sections or segmented spine struts can be coupled to each of the electrode(s) at attachment points. The attachment points can permit the segmented spine struts to rotate around each respective attachment point.

DETAILED DESCRIPTION

As used herein, the terms “patient,” “host.” “user,” and “subject” refer to any human or animal subject and are not intended to limit the systems or methods to human use, although use of the subject invention in a human patient represents a preferred embodiment. In addition, vasculature of a “patient,” “host,” “user,” and “subject” can be vasculature of a human or any animal. It should be appreciated that an animal can be a variety of any applicable type, including, but not limited thereto, mammal, veterinarian animal, livestock animal or pet type animal, etc. As an example, the animal can be a laboratory animal specifically selected to have certain characteristics similar to a human (e.g., rat, dog, pig, monkey, or the like). It should be appreciated that the subject can be any applicable human patient, for example. As well, the term “proximal” indicates a location closer to the operator or physician whereas “distal” indicates a location further away to the operator or physician.

As discussed herein, “operator” can include a doctor, surgeon, technician, scientist, or any other individual or delivery instrumentation associated with delivery of a multi-electrode catheter for the treatment of drug refractory atrial fibrillation to a subject.

As discussed herein, the term “ablate” or “ablation”, as it relates to the devices and corresponding systems of this disclosure, refers to components and structural features configured to reduce or prevent the generation of erratic cardiac signals in the cells by utilizing non-thermal energy, such as irreversible electroporation (IRE), referred throughout this disclosure interchangeably as pulsed electric field (PEF) and pulsed field ablation (PFA). Ablating or ablation as it relates to the devices and corresponding systems of this disclosure is used throughout this disclosure in reference to non-thermal ablation of cardiac tissue for certain conditions including, but not limited to, arrhythmias, atrial flutter ablation, pulmonary vein isolation, supraventricular tachycardia ablation, and ventricular tachycardia ablation. The term “ablate” or “ablation” also includes known methods, devices, and systems to achieve various forms of bodily tissue ablation as understood by a person skilled in the relevant art.

As discussed herein, the terms “bipolar” and “unipolar” when used to refer to ablation schemes describe ablation schemes which differ with respect to electrical current path and electric field distribution. “Bipolar” refers to ablation scheme utilizing a current path between two electrodes that are both positioned at a treatment site; current density and electric flux density is typically approximately equal at each of the two electrodes. “Unipolar” refers to ablation scheme utilizing a current path between two electrodes where one electrode including a high current density and high electric flux density is positioned at a treatment site, and a second electrode including comparatively lower current density and lower electric flux density is positioned remotely from the treatment site.

As discussed herein, the terms “biphasic pulse” and “monophasic pulse” refer to respective electrical signals. “Biphasic pulse” refers to an electrical signal including a positive-voltage phase pulse (referred to herein as “positive phase”) and a negative-voltage phase pulse (referred to herein as “negative phase”). “Monophasic pulse” refers to an electrical signal including only a positive or only a negative phase. Preferably, a system providing the biphasic pulse is configured to prevent application of a direct current voltage (DC) to a patient. For instance, the average voltage of the biphasic pulse can be zero volts with respect to ground or other common reference voltage. Additionally, or alternatively, the system can include a capacitor or other protective component. Where voltage amplitude of the biphasic and/or monophasic pulse is described herein, it is understood that the expressed voltage amplitude is an absolute value of the approximate peak amplitude of each of the positive-voltage phase and/or the negative-voltage phase. Each phase of the biphasic and monophasic pulse preferably has a square shape including an essentially constant voltage amplitude during a majority of the phase duration. Phases of the biphasic pulse are separated in time by an interphase delay. The interphase delay duration is preferably less than or approximately equal to the duration of a phase of the biphasic pulse. The interphase delay duration is more preferably about 25% of the duration of the phase of the biphasic pulse.

As discussed herein, the terms “tubular” and “tube” are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, the tubular structures are generally illustrated as a substantially right cylindrical structure. However, the tubular structures may have a tapered or curved outer surface without departing from the scope of the present disclosure.

The term “temperature rating”, as used herein, is defined as the maximum continuous temperature that a component can withstand during its lifetime without causing thermal damage, such as melting or thermal degradation (e.g., charring and crumbling) of the component.

The present disclosure is related to systems, methods or uses and devices which utilize segmented spines comprising electrodes coupled to spine struts at attachment points. Example systems, methods, and devices of the present disclosure may be particularly suited for IRE ablation of cardiac tissue to treat cardiac arrhythmias. Ablative energies are typically provided to cardiac tissue by a tip portion of a catheter which can deliver ablative energy alongside the tissue to be ablated. Some example catheters include three-dimensional structures at the tip portion and are configured to administer ablative energy from various electrodes positioned on the three-dimensional structures. Ablative procedures incorporating such example catheters can be visualized using fluoroscopy.

Ablation of cardiac tissue using application of a thermal technique, such as radio frequency (RF) energy and cryoablation, to correct a malfunctioning heart is a well-known procedure. Typically, to successfully ablate using a thermal technique, cardiac electropotentials need to be measured at various locations of the myocardium. In addition, temperature measurements during ablation provide data enabling the efficacy of the ablation. Typically, for an ablation procedure using a thermal technique, the electropotentials and the temperatures are measured before, during, and after the actual ablation.

IRE as discussed in this disclosure is a non-thermal cell death technology that can be used for ablation of atrial arrhythmias. To ablate using IRE/PEF, biphasic voltage pulses are applied to disrupt cellular structures of myocardium. The biphasic pulses are non-sinusoidal and can be tuned to target cells based on electrophysiology of the cells. In contrast, to ablate using RF, a sinusoidal voltage waveform is applied to produce heat at the treatment area, indiscriminately heating all cells in the treatment area. IRE therefore has the capability to spare adjacent heat sensitive structures or tissues which would be of benefit in the reduction of possible complications known with ablation or isolation modalities. Additionally, or alternatively, monophasic pulses can be utilized.

Electroporation can be induced by applying a pulsed electric field across biological cells to cause reversable (temporary) or irreversible (permanent) creation of pores in the cell membrane. The cells have a transmembrane electrostatic potential that is increased above a resting potential upon application of the pulsed electric field. While the transmembrane electrostatic potential remains below a threshold potential, the electroporation is reversable, meaning the pores can close when the applied pulse electric field is removed, and the cells can self-repair and survive. If the transmembrane electrostatic potential increases beyond the threshold potential, the electroporation is irreversible, and the cells become permanently permeable. As a result, the cells die due to a loss of homeostasis and typically die by programmed cell death or apoptosis, which is believed to leave less scar tissue as compared to other ablation modalities. Generally, cells of differing types have differing threshold potential. For instance, heart cells have a threshold potential of approximately 500 V/cm, whereas for bone it is 3000 V/cm. These differences in threshold potential allow IRE to selectively target tissue based on threshold potential.

Manufacturing and constructing of a medical probe capable of IRE as discussed above will now be discussed. Basket assemblies of medical probes can have a traumatic shape, particularly when it is expanded. Additionally, cutting the basket and current electrode installation can also be complicated. A solution is needed to overcome these installation issues that would also permit the formation of a basket assembly in various sizes and in multiple shapes.

The solution of this disclosure includes systems and methods for constructing a basket assembly. By coupling a plurality of spine struts together with an electrode at attachment points, manufacturing and installation issues as presented above can be avoided. A basket assembly that can easily be coupled together with attachment points permits the formation of basket assemblies of various sizes with spine struts of different sizes being coupled together. Attachment points also allow the spine struts to rotate about the attachment point to form various shapes with the plurality of spines.

FIG.1is a schematic, pictorial illustration of a medical system10including a medical probe16and a patient interface unit30, in accordance with an embodiment of the present invention. Medical system10may be based, for example, on the CARTO® system, produced by Biosense Webster Inc. of 31 Technology Drive, Suite 200, Irvine, CA 92618 USA. In embodiments described hereinbelow, medical probe16can be used for diagnostic or therapeutic treatment, such as for performing ablation procedures in a heart12of a patient23. Alternatively, medical probe16may be used, mutatis mutandis, for other therapeutic and/or diagnostic purposes in the heart or in other body organs.

Medical probe16includes a plurality of segmented struts22, electrodes26coupled to a proximal end of the tubular shaft. During a medical procedure, a medical professional24can insert the medical probe16through the vascular system of patient23so that a distal end85of the medical probe enters a body cavity such as a chamber of heart12. Upon distal end85entering the chamber of heart12, medical professional24can deploy a basket assembly38approximate a distal end85of the medical probe16. Basket assembly38can include a plurality of electrodes26affixed to a plurality of segmented struts22, as described in the description referencingFIGS.2through6hereinbelow. To start performing a medical procedure such as irreversible electroporation (IRE) ablation, medical professional24can manipulate a handle to position distal end85so that electrodes26engage cardiac tissue at a desired location or locations. Upon positioning the distal end85so that electrodes26engages cardiac tissue, the medical professional24can activate the medical probe16such that electrical pulses are delivered by the electrodes26to perform the IRE ablation.

The medical probe16can include a guide sheath and a therapeutic catheter, wherein the guide sheath includes the flexible insertion tube and the handle, and the therapeutic catheter includes the basket assembly38, electrodes26, and a tubular shaft84(seeFIGS.2through5). The therapeutic catheter is translated through the guide sheath so that the basket assembly38is positioned in the heart12. The distal end85of the medical probe16corresponds to a distal end of the guide sheath when the basket assembly38is contained within the flexible insertion tube, and the distal end85of the medical probe16corresponds to a distal end of the basket assembly38when the basket assembly38is extended from the distal end of the guide sheath. The medical probe16can be alternatively configured to include a second handle on the therapeutic catheter and other features as understood by a person skilled in the pertinent art.

In the configuration shown inFIG.1, patient interface unit30is connected, by a cable, to body surface electrodes, which typically include adhesive skin patches44that are affixed to patient23. Patient interface unit30includes a processor that, in conjunction with a position sensor29, determines location coordinates of distal end85inside heart12. Location coordinates can be determined based on electromagnetic position sensor output signals provided from the distal portion of the catheter when in the presence of a generated magnetic field. Location coordinates can additionally, or alternatively be based on impedances and/or currents measured between adhesive skin patches and electrodes26that are affixed to basket assembly38. In addition to being used as location sensors during a medical procedure, electrodes26may perform other tasks such as ablating tissue in the heart.

As described hereinabove, in conjunction with position sensor29, processor may determine location coordinates of distal end85inside heart12based on impedances and/or currents measured between adhesive skin patches and electrodes26. Such a determination is typically after a calibration process relating the impedances or currents to known locations of the distal end has been performed. While embodiments presented herein describe electrodes26that are preferably configured to deliver IRE ablation energy to tissue in heart12. configuring electrodes26to deliver any other type of ablation energy to tissue in any body cavity is considered to be within the spirit and scope of the present invention. Furthermore, although described in the context of being electrodes26that are configured to deliver IRE ablation energy to tissue in the heart12, one skilled in the art will appreciate that the disclosed technology can be applicable to electrodes used for mapping and/or determining various characteristics of an organ or other part of the patient's23body.

Processor may include real-time noise reduction circuitry typically configured as a field programmable gate array (FPGA), followed by an analog-to-digital (A/D) signal conversion integrated circuit52. The processor can be programmed to perform one or more algorithms and uses circuitry and circuit as well as features of modules to enable the medical professional24to perform the IRE ablation procedure.

Patient interface unit30also includes an input/output (I/O) communications interface that enables patient interface unit30to transfer signals from, and/or transfer signals to electrodes26and adhesive skin patches. In the configuration shown inFIG.1, patient interface unit30additionally includes an IRE ablation module and a switching module.

IRE ablation module is configured to generate IRE pulses including peak power in the range of tens of kilowatts. In some examples, the electrodes26are configured to deliver electrical pulses including a peak voltage of at least 700 volts (V). The medical system10performs IRE ablation by delivering IRE pulses to electrodes26. Preferably, the medical system10delivers biphasic pulses between electrodes26on the spine. Additionally, or alternatively, the medical system10delivers monophasic pulses between at least one of the electrodes26and a skin patch.

Irrigation is sometimes utilized to reduce clot formation, stagnant blood flow or even reduce heat generated by ablation via the electrodes. As such, system10may supply irrigation fluid (e.g., a saline solution) to distal end85and to the electrodes26via a channel (not shown) in tubular shaft84(seeFIGS.2through5). Additionally, or alternatively, irrigation fluid can be supplied through the flexible insertion tube. Patient interface unit30includes an irrigation module to monitor and control irrigation parameters, such as the pressure and the temperature of the irrigation fluid.

Based on signals received from electrodes26and/or adhesive skin patches, processor can generate an electroanatomical map20that shows the location of distal end85in the patient's body. During the procedure, processor can present map20to medical professional24on a display27, and store data representing the electroanatomical map20in a memory. Memory may include any suitable volatile and/or non-volatile memory, such as random-access memory or a hard disk drive.

In some embodiments, medical professional24can manipulate map20using one or more input devices. In alternative embodiments, display27may include a touchscreen that can be configured to accept inputs from medical professional24, in addition to presenting map20.

FIG.2is a perspective view of a medical probe16including a basket assembly38in an expanded form when unconstrained, such as by being advanced out of an insertion tube lumen (seeFIG.6) at a distal end85of an insertion tube. The medical probe16illustrated inFIG.2lacks the guide sheath illustrated inFIG.1. The medical probe16includes segmented struts22(also known as spine sections) that are retained by a loop retention hub180at a distal end of the basket assembly38. The segmented struts22include spine loops that have a distal loop215(seeFIG.7A) and two ends secured in the tubular shaft84. The tubular shaft84is generally aligned along a longitudinal axis86. The segmented spines22are coupled to electrodes26at attachment points25. As illustrated inFIG.2, a strut22can be coupled to the electrode26at an attachment point25, and another strut22can be coupled to the same electrode26at another attachment point25.

FIG.3shows a medical probe16including a basket assembly38in an expanded form when unconstrained, such as by being advanced out of an insertion tube lumen (seeFIG.6) at a distal end85of an insertion tube. The medical probe16illustrated inFIG.2lacks the guide sheath illustrated inFIG.1. The medical probe16includes segmented struts22(also known as spine sections) that are retained by a loop retention hub180at a distal end of the basket assembly38. The segmented struts22include spine loops that have a distal loop215(seeFIG.7A) and two ends secured in the tubular shaft84. The tubular shaft84is generally aligned along a longitudinal axis86. The segmented spines22are coupled to electrodes26at attachment points25. As illustrated inFIG.3, a strut22can be coupled to the electrode26at an attachment point25, and another strut22can be coupled to the same electrode26at another attachment point25. Further illustrated inFIG.3, an attachment point25can allow a strut22to rotate about the attachment point25to create an inverted shape for the basket assembly38.

FIG.4illustrates a perspective view of a medical probe16including a basket assembly38in an expanded form when unconstrained, such as by being advanced out of an insertion tube lumen (seeFIG.6) at a distal end85of an insertion tube. The medical probe16illustrated inFIG.2lacks the guide sheath illustrated inFIG.1. The medical probe16includes segmented struts22(also known as spine sections) that are retained by a loop retention hub180at a distal end of the basket assembly38. The segmented struts22include spine loops that have a distal loop215(seeFIG.7A) and two ends secured in the tubular shaft84. The tubular shaft84is generally aligned along a longitudinal axis86. The segmented spines22are coupled to electrodes26at an attachment point25. As illustrated inFIG.4, a strut22can be coupled to the electrode26at the attachment point25, and another strut22can be coupled to the same electrode26at the same attachment point25.

FIG.5is a perspective view of a medical probe16including a basket assembly38in an expanded form when unconstrained, such as by being advanced out of an insertion tube lumen (seeFIG.6) at a distal end85of an insertion tube. The medical probe16illustrated inFIG.2lacks the guide sheath illustrated inFIG.1. The medical probe16includes segmented struts22(also known as spine sections) that are retained by a loop retention hub180at a distal end of the basket assembly38. The segmented struts22include spine loops that have a distal loop215(seeFIG.7A) and two ends secured in the tubular shaft84. The tubular shaft84is generally aligned along a longitudinal axis86. The segmented spines22are coupled to electrodes26at an attachment point25. As illustrated inFIG.4, a strut22can be coupled to the electrode26at the attachment point25, and another strut22can be coupled to the same electrode26at the same attachment point25. Further illustrated inFIG.5, an attachment point25can allow a strut22to rotate about the attachment point25to create an inverted shape for the basket assembly38.

FIG.6shows a basket assembly38in a collapsed form that can be configured similar to the basket assembly38inFIGS.2through5. The basket assembly38is collapsed within insertion tube of the guide sheath. In the expanded form (FIGS.2through5), plurality of segmented struts22bow radially outwardly and in the collapsed form (FIG.6) the segmented struts22are arranged generally along a longitudinal axis86of insertion tube.

Referring toFIGS.2through6, during a medical procedure, medical professional24can deploy basket assembly38by extending tubular shaft84from insertion tube causing basket assembly38to exit insertion tube and transition to the expanded form. Spine struts22may have elliptical (e.g., circular) or rectangular (that may appear to be flat) cross-sections, and include a flexible, resilient material (e.g., a shape-memory alloy such as nickel-titanium, also known as Nitinol) forming a segmented strut22as will be described in greater detail herein.

In embodiments described herein, one or more electrodes26positioned on segmented struts22of basket assembly38can be configured to deliver ablation energy (RF and/or IRE) to tissue in heart12. Additionally, or alternatively, the electrodes can also be used to determine the location of basket assembly38and/or to measure a physiological property such as local surface electrical potentials at respective locations on tissue in heart12. The electrodes26can be biased such that a greater portion of the one or more electrodes26face outwardly from basket assembly38such that the one or more electrodes26deliver a greater amount of electrical energy outwardly away from the basket assembly38(i.e., toward the heart12tissue) than inwardly.

Examples of materials ideally suited for forming electrodes26include gold, platinum and palladium (and their respective alloys). These materials also have high thermal conductivity which allows the minimal heat generated on the tissue (i.e., by the ablation energy delivered to the tissue) to be conducted through the electrodes to the back side of the electrodes (i.e., the portions of the electrodes on the inner sides of the spines), and then to the blood pool in heart12.

FIG.7Ais an exploded view of the medical probe16illustrated inFIG.2. The electrodes26are omitted for the sake of illustration. The spine loops include distal loops215that overlap within the loop retention hub180a.The spine loops include two ends that are secured between the tubular shaft84and relief lands96of a spine retention hub90that extends longitudinally from a distal end of the tubular shaft84towards the distal end of basket assembly38.

FIG.7Bis an exploded view of the medical probe16illustrated inFIG.2. The electrodes26are omitted for the sake of illustration. The spine sections214beach include a stopper218that is retained within the loop retention hub180b.The spine sections214beach include a narrow distal portion217that can move longitudinally within slots183of the loop retention hub180bwhen the stopper218rotates to expand or contract the basket assembly38b.The stopper218can have extensions that extend orthogonal to the longitudinal axis to inhibit the stopper218from exiting the slots183. The spine sections214bextend distally from a proximal tube216b.The proximal tube216band the spine sections214bcan be contiguous. In some embodiments, the spine sections214band proximal tube216bcan be cut from a singular tube. Alternatively, the spine sections214bcan have proximal ends.

Referring collectively toFIGS.2through7B, the medical probe16can include a spine retention hub90disposed proximate the distal end85of the tubular shaft84. The spine retention hub90can be inserted into the tubular shaft84and attached to the tubular shaft84. Spine retention hub90can include a cylindrical member94including a plurality of relief lands96, multiple irrigation openings98, and at least one spine retention hub electrode. Relief lands96can be disposed on the outer surface of cylindrical member94and configured to allow a portion of each strut22, such as each spine attachment end216a,to be fitted into a respective relief land96. The attachment end216can be a generally linear end of the spine. The attachment end216can be configured to extend outwardly from the spine retention hub90such that the basket assembly38is positioned outwardly from the spine retention hub90and, consequently, outwardly from the tubular shaft84. In this way, the spine or segmented struts22can be configured to position the basket assembly38distally from the distal end of the tubular shaft84and distal from the distal end of the insertion tube when the basket assembly38is deployed. The relief lands96are preferably omitted when the medical probe16includes a proximal tube216bjoined to the spine sections.

As described supra, patient interface unit30includes irrigation module60that delivers irrigation fluid to distal end85of flexible insertion tube. The multiple irrigation openings98can be angled to spray or otherwise disperse of the irrigation fluid to either a given electrode26or to tissue in heart12. Since electrodes26do not include irrigation openings98that deliver irrigation fluid, the configuration described hereinabove enables heat to be transferred from the tissue (i.e., during an ablation procedure) to the portion of the electrodes26on the inner side of the segmented struts22b,and the electrodes26can be cooled by aiming the irrigation fluid, via irrigation openings98, at the portion of the electrodes26on the inner side of the segmented struts22b.Spine retention hub90electrode disposed at a distal end of retention hub90can be used in combination with electrodes26on the segmented struts22, or alternatively, can be used independently from electrodes26for reference mapping or ablation.

FIG.8illustrates a perspective view of an alternative configuration of spine sections214cthat have a curvature approximate the loop retention hub180. As illustrated, the loop retention hub180can be configured similarly to the loop retention hub180illustrated inFIG.2. Further, as illustrated, the spine sections214can include spine loops each including a distal loop215overlapped within the loop retention hub180and two ends that can be secured within the tubular shaft84. Alternatively, the spine sections214illustrated inFIGS.2through5can be modified to include a curvature in the narrow distal portion217similar to the shape of the spine sections214illustrated inFIG.8.

FIGS.9A and9Bshow a profile shape of a basket assembly38of a given medical device22when the spines sections214are expanded. As shown inFIG.9A, the basket assembly38can be configured to form an approximately spheroid or spherical shape when in the expanded form. As another example, as shown inFIG.9B, the basket assembly38can have an approximately elliptical profile and oblate-spheroid shape when in the expanded form. Although not every variation of shape is shown or described herein, one skilled in the art will appreciate that segmented struts22can be further configured to form other various shapes as would be suitable for the particular application.

By including segmented struts22configured to form various shapes when in the expanded form, basket assembly38can be configured to position the various electrodes26attached to segmented struts22at various locations, with each location being nearer or farther from the distal end of tubular shaft84. For example, electrode26attached to spine214illustrated inFIG.9Anear the middle of spine214would be farther from the distal end of tubular shaft84than spine214illustrated inFIG.9Bwhen basket assembly38is in the expanded form. In addition, each spine214may have an elliptical (e.g., circular) or rectangular (that may appear to be flat) cross-section, and include a flexible, resilient material (e.g., a shape-memory alloy such as nickel-titanium (also known as Nitinol), cobalt chromium, or any other suitable material).

The examples above can have additional struts22and electrodes26to traverse from the insertion tube to the loop retention hub180. Multiple struts22and electrodes26allow the basket assembly38to expand in size. In addition, the strut22can have common ends, i.e., attachment end216, attachment point25, and stoppers218(see below), to engage the various elements. A common strut22can be formed and continuously coupled together with electrodes26to form the basket assembly38, minimizing production costs to increase the size of the basket assembly38. The example ends can be identical on both the proximal and distal ends of the spine or a different one on each end, but matching to be modular to the attachment points.

FIGS.10A and10Bshow a side view of a loop retention hub180aconfigured similarly to the loop retention hub180aillustrated inFIGS.2through6. The loop retention hub180aincludes a first portion182including protrusions184and a second portion186including indentations188. The protrusions184engage the indentations188to clamp the first portion182to the second portion186. The loop retention hub180acan further include a hinge189between the first portion182and the second portion186.

FIGS.11A through11Cillustrate a top-down view of various loop retention hub locking mechanisms184a,184b,184c.

FIG.11Aillustrates a loop retention hub180aconfigured similarly to the loop retention hub180aillustrated inFIGS.10A and10B. The loop retention hub180aincludes triangular protrusions184a(and corresponding indentations not illustrated) defining linear paths between the protrusions184athrough which the distal loops215extend. The distal loops215overlap at a central spine intersection.

FIG.11Billustrates a loop retention hub180cconfigured similarly to the loop retention hub180aillustrated inFIGS.10A and10Bexcepting that the protrusions184c(and corresponding indentations not illustrated) include curvature to accommodate curves of distal loops215through paths between the protrusions184c.The loop retention hub180cmay be particularly suited to retain spine sections214cincluding curvature as illustrated inFIG.8. The narrow distal portion217of each spine section214bcan extend through slots183of the loop retention hub180c.

FIG.11Cillustrates a cross-section of the loop retention hub180billustrated inFIGS.2through7. The stoppers218are positioned within the loop retention hub180band secured in loop retention hub180bwhen clamped around the stoppers218. The stoppers218are secured such that the spine sections214including narrow distal portion217can move longitudinally within slots183of the loop retention hub180.

FIG.12Ais a perspective view of a loop retention hub180aof a self-expanding basket assembly configured similarly to as illustrated inFIGS.2,7A,10B, and11A. The basket assembly38is configured to self-expand upon exiting a flexible insertion tube as described in relation toFIG.6.

FIG.12Bis a perspective view of a loop retention hub180aof an actuated expanding basket assembly38. The basket assembly is configured similarly as illustrated inFIGS.2,7A,10B, and11Aexcepting that the medical probe16further includes a central member190movable along the longitudinal axis86in relation the tubular shaft84to expand and collapse the basket assembly38. The central member190can include a distal end affixed to the second portion186of the loop retention hub180a.

Referring collectively toFIGS.2through12B, electrodes26can be attached to spine sections214before the spine sections are inserted into the tubular shaft84to form the basket assembly38. As stated previously, the segmented struts22can include a flexible, resilient material (e.g., a shape-memory alloy such as nickel-titanium, also known as Nitinol) that can enable the basket assembly38to transition to its expanded form (as shown inFIG.2) when the basket assembly38is deployed from flexible insertion tube. As will become apparent throughout this disclosure, segmented struts22can be electrically isolated from electrode26to prevent arcing from electrode26to the respective spine.

In some examples, each electrode26can include electrically conductive material (e.g., gold, platinum and palladium (and their respective alloys)). Turning toFIGS.13A through13J, electrode26can have a variety of cross-sectional shapes, curvatures, lengths, lumen number and lumen shape as provided as examples in electrodes26a,26b.The electrodes26a,26bare offered to illustrate various configurations of electrodes26that can be used with the medical device but should not be construed as limiting. One skilled in the art will appreciate that various other configurations of electrodes26can be used with the disclosed technology without departing from the scope of this disclosure.

Each electrode26can have an outer surface26afacing outwardly from electrode26and an inner surface26bfacing inwardly toward electrode26where at least one lumen770is formed through electrode26. The lumen770can be sized and configured to receive a spine such that spine can pass through electrode26. Lumen770can be a symmetric opening through electrode26a-26band can be disposed offset with respect to a longitudinal axis L-L of the respective electrode. In other examples, lumen770can pass through electrode26in a generally transverse direction with respect to the longitudinal axis L-L of the respective electrode. Furthermore, lumen770can be positioned in electrode26nearer a bottom surface, nearer a top surface, or nearer a middle of electrode26depending on the particular configuration. InFIGS.13A,13C, and13E through13J, the top surface (upper side) is oriented toward the top of the drawing, the bottom surface (lower side) is oriented toward the bottom of the drawing, and the middle is between the top surface and the bottom surface. In other words, each electrode26a-26bcan include a lumen770that is offset with respect to a centroid of the electrode26a-26b.

In addition, as shown inFIGS.13A through13F, electrodes26A-26C can have a wire relief772forming a recess or depression in electrode26adjacent lumen770for one or more wires to pass through lumen770along with a respective spine214. Relief772can be sized to provide room for a wire of electrode26to pass through electrode26such that electrode26can be in electrical communication with the patient interface unit30.

Alternatively, or in addition thereto, wires can pass through a wire lumen773as shown in example electrodes26inFIGS.13G through13J. Although not depicted, electrodes26may include both a wire relief772adjacent lumen770and wire lumen773. Such electrode may permit additional wires to pass through the electrode body.

As shown inFIGS.13A through13J, the electrodes26can include various shapes depending on the application. For example, as illustrated inFIGS.13A and13B, the electrode26can comprise a substantially rectangular cuboid shape with rounded edges. In other examples, the electrode26can comprise a substantially ovoid shape (as illustrated inFIGS.13C and13D), the electrode26can have a contoured shape including a convex side and a concave side (as illustrated inFIGS.13E through13H), or the electrode26can have a contoured shape including substantially more material proximate an upper side than a lower side of the electrode26(as illustrated inFIGS.13I and13J). As will be appreciated by one of skill in the art, the various example electrodes26shown inFIGS.13A through13J, and described herein, are offered for illustrative purposes and should not be construed as limiting.

FIG.14is a flowchart illustrating a method1400of constructing a basket assembly38, in accordance with an embodiment of the present invention. Method1400can include coupling (step1405) at least one end of one or more electrodes26to each of a plurality of spine struts222. The one or more electrodes26can be coupled to each of the spine struts22at attachment points. The method1400can include coupling (step1410) at least a second end of the one or more electrodes26to each of a second plurality of spine struts22. Each of the plurality of spine struts22and each of the second plurality of spine struts22can be moveable to permit each respective spine strut to rotate around each respective attachment point. Method1400can include connecting (step1415) at least one end of each of the spine struts22to a distal retention hub. Method1400can include connecting (step1420) at least one end of the spine struts22to a distal end of a tubular shaft84.

As will be appreciated by one skilled in the art, method1400can include any of the various features of the disclosed technology described herein and can be varied depending on the particular configuration. Thus, method1400should not be construed as limited to the particular steps and order of steps explicitly described herein. It is noted that while the preference for the exemplary embodiments of the medical probe is for IRE or PFA, it is within the scope of the present invention to also use the medical probe separately only for RF ablation (unipolar mode with an external grounding electrode or bipolar mode) or in combination with IRE and RF ablations sequentially (certain electrodes in IRE mode and other electrodes in RF mode) or simultaneously (some electrodes in IRE mode and other electrodes in RF mode).

The disclosed technology described herein can be further understood according to the following clauses:Clause 1: A segmented spine comprising: a first electrode; a first spine strut comprising a first attachment point configured to couple with the first electrode; and a second spine strut comprising a second attachment point configured to couple with the first electrode.Clause 2: The segmented spine according to Clause 1, wherein the first spine strut further comprises a third attachment point configured to engage with a distal retention hub.Clause 3: The segmented spine according to Clause 1, wherein the second spine strut further comprises a fourth attachment point configured to engage with a tubular shaft.Clause 4: The segmented spine according to Clause 1, wherein the first attachment point of the first spine strut and the second attachment point of the second spine strut are configured to permit the first spine strut and second spine strut to rotate around the respective attachment point.Clause 5: The segmented spine according to any of Clauses 1-4, further comprising: a second electrode; a third spine strut comprising a fifth attachment point configured to engage with the second electrode; and a fourth spine strut comprising a sixth attachment point configured to engage with the second electrode.Clause 6: The segmented spine according to Clause 5, wherein the third spine strut further comprises a seventh attachment point configured to engage with a distal retention hub.Clause 7: The segmented spine according to Clause 5, wherein the fourth spine strut further comprises an eighth attachment point configured to engage with a tubular shaft.Clause 8: The segmented spine according to Clause 5, wherein the fifth attachment point of the third spine strut and the sixth attachment point of the fourth spine strut are configured to permit the third spine strut and fourth spine strut to rotate around the respective attachment point.Clause 9: The segmented spine according to any of Clauses 1-8, wherein a plurality of segmented spines are configured to move from an inverted tubular configuration to an expanded spherical configuration.Clause 10: An expandable basket assembly comprising: a plurality of segmented spines disposed about a longitudinal axis and coupled to each other, each of the plurality of segmented spines comprising: a first electrode disposed along the longitudinal axis; a first spine strut coupled to the first electrode; and a second spine strut coupled to the first electrode.Clause 11: The expandable basket assembly according to Clause 10, wherein the first spine strut further comprises a second attachment point configured to engage with a distal retention hub.Clause 12: The expandable basket assembly according to Clause 10, wherein the second spine strut further comprises a third attachment point configured to engage with a tubular shaft.Clause 13: The expandable basket assembly according to any of Clauses 10-13, wherein a first attachment point of the first spine strut and the second spine strut are configured to permit the first spine strut and second spine strut to rotate around the first attachment point.Clause 14: The expandable basket assembly according to any of Clauses 10-13, wherein the plurality of segmented spines are configured to move from an inverted tubular configuration to an expanded spherical configuration.Clause 15: The expandable basket assembly according to any of Clauses 10-14, wherein each of the plurality of segmented spines further comprise: a second electrode; a third spine strut; and a fourth spine strut, wherein the third spine strut and the fourth spines strut each comprise a fourth attachment point configured to engage with the second electrode.Clause 16: The expandable basket assembly according to Clause 15, wherein the third spine strut further comprises a fifth attachment point configured to engage with a distal retention hub.Clause 17: The expandable basket assembly according to Clause 15, wherein the fourth spine strut further comprises a sixth attachment point configured to engage with a tubular shaft.Clause 18: The expandable basket assembly according to any one of Clauses 10-17, wherein the plurality of segmented spines are configured to form geographical configurations.Clause 19: The expandable basket assembly according to any one of Clauses 10-18, wherein the plurality of segmented spines are configured to form a first portion and a second portion configured to mate with each other to retain a distal portion of each of the plurality of segmented spines at a central spine intersection.Clause 20: The expandable basket assembly according to any one of Clauses 10-19, wherein the expandable basket assembly defines a spherical outer profile.Clause 21: The expandable basket assembly according to any one of Clauses 10-20, wherein the expandable basket assembly defines an oblate-spheroid profile.Clause 22: The expandable basket assembly according to any one of Clauses 10-21, wherein each electrode is configured to deliver electrical pulses for irreversible electroporation, the electrical pulses including a peak voltage of at least 900 volts (V).Clause 23: The expandable basket assembly according to any one of Clauses 10-22, further comprising a spine retention hub disposed proximate the distal end of a tubular shaft, the spine retention hub comprising a cylindrical member including a plurality of relief lands disposed on an outer surface of the cylindrical member to allow each spine strut to be fitted into the relief land and retained therein, the spine retention hub further comprising at least one electrode disposed at a distal portion of the spine retention hub.Clause 24: The expandable basket assembly according to any one of Clauses 23, wherein the plurality of segmented spines comprises spine loops, each spine loop comprising a single unitary loop including a distal loop and two ends secured between the tubular shaft and in one of the relief lands of the spine retention hub.Clause 25: The expandable basket assembly according to Clause 24, wherein the distal loops of each spine loop overlap within the distal retention hub.Clause 26: The expandable basket assembly according to Clause 25, wherein the distal retention hub further comprises: two or more protrusions positioned on a first portion and/or a second portion; and two or more indentations positioned on the opposite portion of the first portion and the second portion, the indentations engaging the protrusions to clamp the first portion to the second portion.Clause 27: The expandable basket assembly according to Clause 26, wherein the plurality of segmented spines fit within paths formed between the two or more protrusions.Clause 28: The expandable basket assembly according to any one of Clauses 10-27, wherein each electrode comprises a wire relief adjacent a lumen to allow for one or more wires to extend adjacent to the lumen.Clause 29: The expandable basket assembly according to Clause 28, wherein the lumen is disposed symmetrically about a longitudinal axis of each electrode.Clause 30: The expandable basket assembly according to any one of Clauses 28-29, wherein the lumen is disposed offset with respect to a longitudinal axis of each electrode.Clause 31: The expandable basket assembly according to any one of Clauses 10-30, further comprising a plurality of insulative sleeves each disposed over the respective given spine strut and within the lumen of the respective electrode.Clause 32: The expandable basket assembly according to any one of Clauses 10-31, further comprising: a plurality of wires each electrically joined to a respective electrode, wherein at least a portion of the wires of the plurality of the wires respectively comprises an electrically conductive core material comprising a first electrical conductivity, an electrically conductive cover material comprising a second electrical conductivity less than the first electrical conductivity, the electrically conductive cover material circumscribing the electrically conductive core material, and an insulative jacket circumscribing the electrically conductive cover material.Clause 33: The expandable basket assembly according to any one of Clauses 10-31, further comprising: a plurality of wires each electrically joined to a respective electrode, wherein at least a portion of the wires of the plurality of the wires respectively comprises a plurality of strands and an insulative jacket circumscribing the plurality of the strands, and wherein each strand of the plurality of strands respectively comprises an electrically conductive core material comprising a first electrical conductivity and an electrically conductive cover material comprising a second electrical conductivity less than the first electrical conductivity, the electrically conductive cover material circumscribing the electrically conductive core material.Clause 34: The expandable basket assembly according to any one of Clauses 10-33, wherein the plurality of segmented spines comprises nitinol.Clause 35: The expandable basket assembly according to any one of Clauses 10-33, wherein the plurality of segmented spines comprises metallic strands.Clause 36: A method of constructing an expandable basket assembly, the method comprising: coupling at least one end of one or more electrodes to each of a plurality of spine struts, the one or more electrodes being coupled to each of the spine struts at attachment points; and coupling at least a second end of the one or more electrodes to each of a second plurality of spine struts, each of the plurality of spine struts and each of the second plurality of spine struts are moveable to permit each respective spine strut to rotate around each respective attachment point.Clause 37: The method of Clause 36, further comprising: connecting at least one end of each of the spine struts to a distal retention hub.Clause 38: The method of any one of Clauses 36-37, further comprising: connecting at least one end of each of the spine struts to a distal end of a tubular shaft.Clause 39: The method of any one of Clauses 36-38, further comprising: configuring the plurality of spine struts and the second plurality of spine struts to extend radially outward from a longitudinal axis to define a shape.Clause 40: The method of any one of Clauses 36-39, wherein the plurality of spine struts and the second plurality of spine struts are configured to move from an inverted tubular configuration to an expanded spherical configuration.Clause 41: The method of any one of Clauses 39-40, wherein the shape is approximately spherical.Clause 42: The method of any one of Clauses 39-41, wherein the shape is approximately oblate-spheroid.Clause 43: The method of any one of Clauses 39-42, wherein the shape is a basket shape.Clause 44: The method of Clause 43, wherein the basket shape is configured to be opened by disconnecting electrodes from spine struts at the attachment points.Clause 45: The method of any one of Clauses 38-44, wherein the plurality of spine struts comprises spine loops, each spine loop comprising a single unitary loop including a distal loop, the method further comprising: securing two ends of each of the spine loops in the tubular shaft.Clause 46: The method of any one of Clauses 37-45 further comprising: overlapping distal portions of each spine strut within the distal retention hub.Clause 47: The method of any one of Clauses 37-46, further comprising: engaging two or more protrusions on a first portion and/or a second portion to two or more indentations on an opposite portion of the first portion and the second portion.Clause 48: The method of any one of Clauses 37-47, further comprising: fitting the plurality of spine struts and the second plurality of spine struts within paths formed between the two or more protrusions.

The embodiments described above are cited by way of example, and the present invention is not limited by what has been particularly shown and described hereinabove. Rather, the scope of the invention includes both combinations and sub combinations of the various features described and illustrated hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art.