Method and system for electrosurgical coagulation device - Patent application

Abstract

At least some exemplary embodiments of an electrosurgical coagulation device include applying RF energy between a first electrode and a second electrode, the first electrode and the second electrode defining a gap, flowing a conductive fluid through first and second nozzles of the first electrode, the first nozzle defining a first spray direction and the second nozzle defining a second spray direction, a first angle between the first and second spray directions being equal to or less than 180 degrees as measured through the gap, and flowing the conductive fluid through third and fourth nozzles of the second electrode, the third nozzle defining a third spray direction and the fourth nozzle defining a fourth spray direction, a second angle between the third and fourth spray directions being equal to or less than 180 degrees as measured through the gap.

Description

[Background technology]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a conversion application of U.S. Provisional Application No. 63 / 034,603, entitled "Methods and Systems for Electrosurgical Coagulation Devices," filed June 4, 2020. This application is also a conversion application of U.S. Provisional Application No. 62 / 936,185, entitled "Bipolar Irrigating Electrosurgery," filed November 15, 2019. Both provisional applications are incorporated herein by reference as if reproduced in full below.

[0002] Coagulation devices, and particularly those used in joint arthroplasty, include the delivery of saline to the active tip of the device and to tissue at the target site. The saline is delivered to create a pool of saline around the tip of the device at the site. The volume and distribution of saline around the electrodes of the device, as well as the amount of saline delivered, are controlled to affect the width, brace, and invasiveness of the coagulation. Summary of the Invention

[0003] One exemplary embodiment is a method of operating an electrosurgical coagulation device, the method including applying radio frequency (RF) energy between a first electrode and a second electrode, the first electrode defining a first longitudinal axis, the second electrode defining a second longitudinal axis coplanar with the first longitudinal axis, the first electrode and the second electrode defining a gap; and flowing a conductive fluid through a first nozzle and a second nozzle of the first electrode, the first nozzle forming a first spray. and flowing the conductive fluid through a third nozzle and a fourth nozzle of the second electrode, wherein the third nozzle defines a third spray direction and the fourth nozzle defines a fourth spray direction, and the second angle between the first spray direction and the second spray direction is 180 degrees or less as measured through the gap.

[0004] In an exemplary method, the first angle may be at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less, and the second angle may be at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less.

[0005] In an exemplary method, the first nozzle and the second nozzle may be mirror images across the gap of the locations of the third nozzle and the fourth nozzle, respectively.

[0006] In an exemplary method, the first spray direction, the second spray direction, the third spray direction, and the fourth spray direction can lie in a common plane.

[0007] In an exemplary method, flowing the conductive fluid through the first nozzle and the second nozzle may further include flowing with the first spray direction and the second spray direction forming a first acute angle with respect to the first longitudinal axis, the first acute angle opening toward the target tissue, and flowing the conductive fluid through the third nozzle and the fourth nozzle may further include flowing with the third spray direction and the fourth spray direction forming a second acute angle with respect to the second longitudinal axis, the second acute angle opening toward the target tissue.

[0008] An exemplary method may further include contacting the target tissue with a rounded contact surface of a first electrode and contacting the target tissue with a rounded contact surface of a second electrode. The rounded contact surface of the first electrode may be ellipsoidal and the rounded contact surface of the second electrode may be ellipsoidal. The rounded contact surface of the first electrode may be spheroidal and the rounded contact surface of the second electrode may be spheroidal.

[0009] In an exemplary method, applying RF energy may further include accepting, with a controller of the electrosurgical coagulation device, instructions for a flow rate setting from a plurality of flow rate settings; accepting, with the controller, instructions for an applied voltage setting; providing energy to the first electrode and the second electrode at a range of voltages determined by the applied voltage settings, where the energy provided varies over time as a function of impedance experienced between the first electrode and the second electrode; and pumping the conductive fluid from the first nozzle to the fourth nozzle, where the flow rate is selected by the controller from a table of applied voltage settings and flow rate settings, where the flow rate remains constant as the energy provided varies over time.

[0010] In an exemplary method, the first longitudinal axis may be parallel to the second longitudinal axis.

[0011] Another exemplary embodiment is an electrosurgical device comprising a handle having an irrigation lumen disposed therein, a cable coupled to a proximal end of the handle, the cable defining a first electrical conductor and a second electrical conductor, an elongate shaft coupled to the handle and defining a distal end opposite the handle, a first electrode disposed on the distal end of the elongate shaft and electrically coupled to the first electrical conductor, the first electrode defining a rounded contact surface opposite the distal end of the elongate shaft, a non-circular intermediate cross-section, and a first longitudinal axis, and a second electrode disposed on the distal end of the elongate shaft and electrically coupled to the second electrical conductor, the second electrode defining a rounded contact surface opposite the distal end of the elongate shaft, a non-circular intermediate cross-section, and a first longitudinal axis. an electrosurgical device comprising: a second electrode defining a rounded contact surface opposite an end, a non-circular intermediate cross-section, and a second longitudinal axis coplanar with the first longitudinal axis; a first nozzle defined by the first electrode, the first nozzle being fluidly coupled to an irrigation lumen, the first nozzle defining a first spray direction between 0 degrees (°) and 90 degrees, inclusive, relative to a line intersecting both the first longitudinal axis and the second longitudinal axis; and a second nozzle defined by the second electrode, the second nozzle being fluidly coupled to the irrigation lumen, the second nozzle defining a second spray direction between 0 degrees and 90 degrees, inclusive, relative to the line.

[0012] An exemplary electrosurgical device may further include a third nozzle defined by a first electrode, the third nozzle fluidly coupled to the irrigation lumen, the third nozzle defining a third spray direction, the first spray direction and the third spray direction defining a first angle bisected by a line, the first angle being less than or equal to 180°, and a fourth nozzle defined by a second electrode, the fourth nozzle fluidly coupled to the irrigation lumen, the fourth nozzle defining a fourth spray direction, the second spray direction and the fourth spray direction defining a second angle bisected by a line, the second angle being less than or equal to 180°. The first angle may be at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less, and the second angle may be at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less. The orientation of the first and third nozzles may be a mirror image across the gap between the first and second electrodes of the locations of the second and fourth nozzles, respectively.

[0013] In an exemplary electrosurgical device, the first spray direction, the second spray direction, the third spray direction, and the fourth spray direction can lie in a common plane.

[0014] An exemplary electrosurgical device may further include, the first and third spray directions may form a first acute angle with respect to the first longitudinal axis, the first acute angle opening toward a rounded contact surface of the first electrode, and the second and fourth spray directions may form a second acute angle with respect to the second longitudinal axis, the second acute angle opening toward a rounded contact surface of the second electrode.

[0015] In an exemplary electrosurgical device, the rounded contact surface of the first electrode may be ellipsoidal and the rounded contact surface of the second electrode may be ellipsoidal.

[0016] In an exemplary electrosurgical device, the rounded contact surface of the first electrode may be spheroidal and the rounded contact surface of the second electrode may be spheroidal.

[0017] In an exemplary electrosurgical device, a first electrode may be rigidly coupled to the elongate shaft and immovable relative to a second electrode, and the second electrode may be rigidly coupled to the elongate shaft and immovable relative to the first electrode.

[0018] In the electrosurgical device, a line between an apex of the rounded contact surface of the first electrode and an apex of the rounded contact surface of the second electrode can be perpendicular to a first longitudinal axis of the first electrode.

[0019] In an exemplary electrosurgical device, the first and second electrodes each have a polygonal cross-section. The first and second electrodes may each have a square cross-section.

[0020] In an exemplary electrosurgical device, the first and second electrodes may each have a square cross-section with chamfered corners.

[0021] In an exemplary electrosurgical device, the second longitudinal axis may be parallel to the first longitudinal axis.

[0022] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will become apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0023] For a detailed description of the exemplary embodiments, reference is now made to the accompanying drawings. [Figure 1] 1 illustrates an electrosurgical coagulation system in accordance with at least some embodiments. [Diagram 2] 1 shows a perspective view of a probe 102 according to at least some embodiments. [Figure 3A]1 illustrates, in block diagram form, an elevational view of a distal end of a device in contact with tissue, according to at least some embodiments. [Figure 3B] 3B-3B of FIG. 3A shows a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 3B-3B of FIG. 3A. [Figure 4A] 1 illustrates a front elevation view of a distal end of a device according to at least some embodiments. [Figure 4B] 4B shows a cross-sectional view of the electrode taken substantially along line 4B-4B of FIG. 4A. [Figure 4C] 1 illustrates a side elevation view of an electrode according to at least some embodiments. [Figure 5A] 1 illustrates a front elevation view of a distal end of a device according to at least some embodiments. [Figure 5B] 5B-5B of FIG. 5A shows a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 5B-5B of FIG. 5A. [Figure 6A] 1 illustrates both a front elevation view of an electrode as well as a cross-sectional view of the electrode, according to at least some embodiments. [Figure 6B] 1 illustrates both a front elevation view of an electrode as well as a cross-sectional view of the electrode, according to at least some embodiments. [Figure 7A] 1 illustrates both a front elevation view of an electrode as well as a cross-sectional view of the electrode, according to at least some embodiments. [Figure 7B] 1 illustrates both a front elevation view of an electrode as well as a cross-sectional view of the electrode, according to at least some embodiments. [Figure 8A] 1 illustrates a front elevation view of a distal end of a device according to at least some embodiments. [Figure 8B] 8B shows a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 8B-8B of FIG. 8A. [Figure 9A] 1 illustrates a front elevation view of a distal end of a device according to at least some embodiments. [Figure 9B] 9B-9B of FIG. 9A shows a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 9B-9B of FIG. 9A. [Figure 10A] 1 illustrates a front elevation view of an electrode according to at least some embodiments. [Figure 10B] 10B shows a cross-sectional view of the electrode of FIG. 10A according to at least some embodiments. [Figure 10C] 1 illustrates a cross-sectional view of an electrode according to at least some embodiments, where the spray direction forms an acute angle with the central longitudinal axis of the electrode. [Figure 10D] 10D shows a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 10D-10D of FIG. 10C. [Figure 11A] 1 illustrates a side elevation view of an electrode according to at least some embodiments. [Figure 11B] 1 illustrates a cross-sectional front elevation view of an electrode according to an exemplary embodiment. [Figure 12] 1 illustrates a partial cross-sectional view of an apparatus according to at least some embodiments. [Figure 13] 1 illustrates a side elevation view of an electrode according to at least some embodiments. [Figure 14] FIG. 1 illustrates a perspective view of a distal end of a device according to at least some embodiments. [Figure 15] 1 illustrates a simplified cross-sectional view of a conductive tube, a fluid delivery tube, and an electrode, according to at least some embodiments. [Figure 16] 1 illustrates a simplified cross-sectional view of a portion of a fluid delivery tube according to at least some embodiments. [Figure 17] FIG. 1 illustrates a perspective view of a distal end of a device according to at least some embodiments. [Figure 19] FIG. 1 illustrates a perspective view of an apparatus according to at least some embodiments. [Figure 20] 1 shows a graph of applied voltage versus pump speed, according to at least some embodiments. [Figure 21] 1 illustrates, in block diagram form, an example coagulation controller according to at least some embodiments.

[0024] definition Various terms are used to refer to specific system components. Different companies may refer to components by different names - this document does not intend to distinguish between components that differ in name but not function. In the following discussion and claims, the terms "including" and "comprising" are used in an open-ended manner and therefore should be interpreted as "including but not limited to." Also, the terms "couple" or "couples" are intended to mean either an indirect or direct connection. Thus, when a first device couples to a second device, the connection may be through a direct connection or through an indirect connection by other devices and connections.

[0025] "Ellipsoid" shall mean a surface defining three major axes intersecting a center of symmetry. A "spheroid" surface is a subset of an ellipsoid in which the three major axes are of equal length.

[0026] The "spray direction" of a nozzle shall refer to the direction that the column of saline initially travels as the fluid exits the nozzle. "Spray direction" should not be read as requiring that the fluid be broken up or atomized into droplets by the nozzle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The following discussion is directed to various embodiments of the present invention. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used as limiting the scope of the present disclosure, including the claims. In addition, those skilled in the art will understand that the following description has a wide range of applications, and the discussion of any embodiment is intended to be only an example of that embodiment, and is not intended to imply that the scope of the present disclosure, including the claims, is limited to that embodiment.

[0028] Various exemplary embodiments are directed to electrosurgical coagulation apparatus methods and systems. In particular, exemplary embodiments are directed to an electrosurgical coagulation apparatus having a first electrode and a second electrode disposed on a distal end of an elongated shaft, the elongated shaft being coupled to a handle. The electrodes are arranged to define a gap between the electrodes, and radio frequency (RF) energy is applied across the electrodes in a bipolar fashion to achieve coagulation. The conductive fluid emerges from a nozzle of the electrodes, and in some cases, a spray direction of the conductive fluid from each electrode toward the other electrode to provide controlled wetting of the target tissue and controlled dispersion of the conductive fluid. This specification first directs the reader to the electrosurgical coagulation system.

[0029] FIG. 1 illustrates an electrosurgical coagulation system according to at least some embodiments. In particular, the electrosurgical coagulation system 100 comprises an electrosurgical coagulation device 104 (hereinafter simply "device 104") including an elongated shaft 106 defining a distal end 108. Additionally, the device 104 comprises a grip or handle 110 at which a clinician holds the device 104 during a surgical procedure. The device 104 further comprises a flexible multi-conductor cable 112 housing one or more electrical conductors or leads (not specifically shown), which terminates in a probe connector 114. As shown in FIG. 1, the device 104 is coupled to a coagulation controller 116, such as by a controller connector 118 on an outer surface of an enclosure 120 (in the illustrative case of FIG. 1, a front surface of the enclosure 120).

[0030] Although not visible in the view of FIG. 1, in some embodiments, the device 104 has an internal flow channel or fluid irrigation lumen. The fluid irrigation lumen of the device 104 is coupled to a flexible tubular member 122 that is used to provide saline to the distal end 108 of the device 104. According to an exemplary embodiment, the flexible tubular member 122 is coupled to a peristaltic pump 124, which is illustratively shown as an integral component of the coagulation controller 116 (i.e., residing at least partially within the enclosure 120 of the coagulation controller 116). In other embodiments, the enclosure of the peristaltic pump 124 may be separate from the enclosure 120 of the coagulation controller 116 (as shown by the dashed lines in the figure).

[0031] The exemplary peristaltic pump 124 includes a rotor portion 126 (hereinafter simply "rotor 126") as well as a stator portion 128 (hereinafter simply "stator 128"). A flexible tubular member 122 is coupled within the peristaltic pump 124 between the rotor 126 and the stator 128, and movement of the rotor 126 relative to the flexible tubular member 122 causes movement of fluid from the aspiration portion 130 toward the distal end 108 of the probe 102. Although the exemplary peristaltic pump 124 is shown with a two-headed rotor 126, other types of peristaltic pumps 124 can be used (e.g., a five-headed peristaltic pump). In the context of various embodiments, the peristaltic pump 124 creates a volumetrically controlled flow of conductive fluid (e.g., saline, Ringer's solution) at the distal end 108 of the probe 104 to a surgical field (not specifically shown). Hereinafter, "conductive fluid" will be referred to as saline, with the understanding that any suitable conductive fluid may be used. The rate of saline flow is based on the speed of rotor 126 as commanded by coagulation controller 116. Suction 130 may be connected to any suitable source of saline, such as a hanging bag or other container. In other cases, any pump system that provides a volumetrically controlled flow when activated (e.g., a centrifugal pump with speed control) may be used.

[0032] 1 , a display or interface device 132 is visible through the enclosure 120 of the coagulation controller 116, and in some embodiments, the interface device 132 and associated buttons 134 allow a user to select an operating mode of the coagulation controller 116. For example, using one or more of the buttons 134, a clinician can select a saline flow rate. As another example, using one or more of the buttons 134, a clinician can select an applied voltage setting to control the invasiveness of the coagulation.

[0033] In some embodiments, the electrosurgical coagulation system 100 also includes a foot pedal assembly 136. The foot pedal assembly 136 may include one or more foot pedal devices 138 and 140, a flexible multi-conductor cable 142, and a pedal connector 144. Although only two foot pedal devices 138 and 140 are shown, one or more pedal devices may be implemented. The enclosure 120 of the coagulation controller 116 may include a corresponding connector 146 that is coupled to the pedal connector 144. The clinician may use the foot pedal assembly 136 to control various aspects of the coagulation controller 116. For example, the foot pedal device 138 may be used to on-off control the application of RF energy to the distal end 108 of the device 104. Additionally, the foot pedal device 140 may be used to control and / or set the flow of saline to the distal end 108 of the device 104. Alternatively, control of various operational or performance aspects of the coagulation controller 116 (e.g., settings of applied voltage) may be initiated by selectively depressing an electrical switch or button 148 located on the handle 110 of the probe 102.

[0034] FIG. 2 shows a perspective view of the device 104 according to at least some embodiments. In particular, visible in FIG. 2 are the handle 110, as well as the elongated shaft 106 and distal end 108. Also visible in FIG. 2 are buttons 148 that the clinician may use to control various aspects of the operation of the device 104 (e.g., on / off control, applied voltage settings, saline flow rate). In particular, button 150 may control the on / off state of the coagulation, while button 152 max controls the increased coagulation function. Energy is delivered to the device 104 from the coagulation controller 116 (FIG. 1) by the flexible multi-conductor cable 112, and saline is delivered by the flexible tubular member 122. Better visible in FIG. 2 are the electrodes at the distal end 108 of the elongated shaft 106, which are electrodes 200 and 202. Each electrode is a metallic structure defining a proximal end coupled to the elongate shaft 106 and an opposite distal end which, in operation, is near or in contact with tissue at the target site during an electrosurgical coagulation procedure. As discussed further below, each electrode 200 and 202 defines an internal irrigation fluid pathway or flow lumen that is in operative relationship with one or more apertures or nozzles. Each nozzle defines a spray direction, with saline passing through the nozzle(s) and exiting each electrode in a direction controlled by the nozzle. In an exemplary embodiment, the nozzles are positioned on the electrodes such that fluid exits each electrode in a direction toward the other electrode.

[0035] Considering again the buttons 148, the exemplary device 104 provides a temporary increased coagulation output to deal with an unexpected amount of blood in the surgical field. The buttons 148 on the handle 110 include an activation button 150 as well as a button 152, which may be referred to as a "MAX button," the actuation of which results in an increase in coagulation (e.g., an increase in energy), but should not necessarily be read as requiring the application of the maximum amount of energy that the coagulation controller 116 (FIG. 1) can provide. When the MAX button 152 is pressed, the device 104 momentarily provides a temporary high coagulation output, for example, to quickly deal with bleeding from a large vessel. As illustrated, the more distal, larger button 150 may be the activation button, and the smaller, lower profile button spaced proximally from the button 150 is the MAX button 152.

[0036] In other cases, rather than using two buttons 150 and 152, a single button can be used to deliver both the selected therapy output and the increased output. For example, a single button can be activated in one direction to provide a therapy output and in a different direction to provide an increased output, such as by depressing the button into the handle for therapy output and moving the button distally to activate the increased output. Alternatively, a rocker button can be used. Inadvertent activation of the increased output can be reduced by making the action required to activate the increased output more deliberate. For example, the user may need to press with more force to activate the increased output, and / or the location of the button may be spaced away from the natural location of the clinician's finger, and / or the size of the button may be smaller, requiring the user to actively locate the button.

[0037] FIG. 3A illustrates, in simplified block diagram form, an elevational view of the distal end of the device 104 according to at least some embodiments in contact with tissue at a target site. In particular, visible in FIG. 3A are the elongate shaft 106, the electrode 200, a portion of the electrode 202, and a portion of the tissue 300 at the target site. In an exemplary embodiment, the electrodes 200 and 202 are rigidly coupled to the elongate shaft 106 on the proximal ends of the electrodes 200 and 202. Thus, in some cases, the electrodes 200 and 202 are immobile relative to each other and the elongate shaft 106. In an exemplary embodiment, the electrodes 200 and 202 are spaced apart from each other, thereby forming an area or interstitial space between the electrodes, referred to as a gap 304. Each electrode 200 and 202 defines an exposed length L as measured from the distal end of the elongate shaft 106 to the distal end of each electrode, and in an exemplary case, the length L of each electrode is the same. As discussed in more detail below, in some cases, the distal end of each electrode is rounded and the length L is measured to the bottom-most point of each electrode (when the electrodes face downward with respect to the force of gravity). Equivalently stated, in cases where the distal end of each electrode is rounded, the length L is measured to the apex of each electrode (when the electrodes face upward with respect to the force of gravity).

[0038] 3A, for effective operation, saline is delivered to a concise volume 302 surrounding the electrodes 200 and 202, including within the gap 304. In particular, fluid delivery is enabled by nozzles (not shown in FIG. 3A ) on each electrode 200 and 202, positioned such that the spray direction of each nozzle delivers saline between the electrodes and also flows to fill the concise volume 302 around the electrodes 200 and 202. Delivering saline in this manner increases the performance of coagulation at the target site and reduces the overall amount of saline used during the procedure.

[0039] In addition to the spray direction of each nozzle (discussed further below), the electrodes 200 and 202 are designed and constructed to enhance wetting within the concise volume 302, and in particular the wetting of the electrodes 200 and 202. To this end, the electrodes 200 and 202 may have features on their exterior surfaces to direct the flow of saline. One exemplary feature includes hydrophobic or hydrophilic surface treatments and / or coatings on the electrodes 200 and 202. Another exemplary feature is the geometry of the fluid outlet (e.g., the spray direction of each nozzle), which may be designed to more effectively distribute the fluid across the gap 304, around the electrodes 200 and 202, and fill the concise volume 302.

[0040] Improved wetting of the electrodes 200 and 202 reduces charring of tissue at the target site, reduces the build-up of charred tissue on the electrodes 200 and 202, and improves maneuverability of the device across the target site tissue 300. In some cases, the distal surfaces of the electrodes 200 and 202 are designed to reduce contact with tissue to enhance maneuverability of the device 104 across the target tissue. The planar surfaces on the sides of the electrodes in some embodiments increase the distance between the nozzles on one electrode and the nozzles on the other electrode, reducing bridging of current between the electrodes through saline.

[0041] FIG. 3B illustrates a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 3B-3B of FIG. 3A. In particular, visible in FIG. 3B are the elongate shaft 200, the electrode 202, and tissue 300 at the target site. As previously described, the electrodes 200 and 202 define a gap 304. In the case of the exemplary electrodes 200 and 202, the gap 304 is defined by the inwardly facing parallel walls and chamfered corners of the electrodes 200 and 202. However, as will become more clear below, the gap 304 may be defined by portions of each electrode 200 and 202 that face each other across the gap between the electrodes, even if the surfaces are not parallel. More precisely, the gap 304 may be the area or volume between the electrodes 200 and 202 bounded by the projection of one electrode over the opposing electrode. 3B, gap 304 is bounded by outwardly facing, coplanar walls on each side of the electrode, as indicated by dashed lines 306 and 308. For example, it follows that exemplary point 312, which lies on compact volume 302, cannot be considered to be within gap 304.

[0042] FIG. 4A illustrates a front elevational view of the distal end of the device according to at least some embodiments. In particular, visible in FIG. 4A are the elongate shaft 106, the exemplary electrode 200, and a portion of the exemplary electrode 202. As previously discussed, the exemplary electrodes 200 and 202 are spaced apart from one another, thereby forming a gap 304. Each electrode 200 and 202 defines an exposed length L as measured from the distal end of the elongate shaft 106 to the distal end of each electrode, and in exemplary cases, the length L of each electrode is the same. The exemplary electrodes 200 and 202 each have a rounded distal end or contact surface 410 and 412 (e.g., for contacting tissue at a target site during a coagulation procedure). In some cases, each rounded contact surface may be ellipsoidal, and in certain cases, the contact surface may be spheroidal. In either case, the shape of the contact surfaces strikes a balance between reducing the area of ​​the contact surface of each electrode 200 and 202 against the tissue at the target site and reducing the amount of force used to move the electrode along the tissue at the target site during use.

[0043] The exemplary electrodes 200 and 202 each define a central longitudinal axis. In particular, the electrode 200 defines a central longitudinal axis 400. Similarly, the electrode 202 defines a central longitudinal axis 402. In the exemplary arrangement, the central longitudinal axes 400 and 402 are coplanar. In the particular case shown, the central longitudinal axes 400 and 402 are parallel. However, in other cases, the central longitudinal axes 400 and 402 may be coplanar but not parallel. For example, the electrodes may be flared or open outward relative to the elongate shaft 106, thereby increasing the volume of the gap 304. In still other cases, the electrodes may be angled inward relative to the elongate shaft 106, thereby decreasing the volume of the gap 304. Although there may be operational advantages to each of the flared and angled arrangements, the operational advantages may not be the same.

[0044] Also visible in FIG. 4A are nozzles on each of the electrodes. In particular, visible in FIG. 4A are apertures or nozzles 404 exposed on the outer surface of electrode 200 and apertures or nozzles 406 exposed on the outer surface of electrode 202. The exemplary nozzle 404 is off-center with respect to electrode 200, and in particular, the outer wall of nozzle 404 is aligned with central longitudinal axis 400 such that nozzle 404 is closer to gap 304. Stated differently, nozzle 404 is on the gap side of central longitudinal axis 400. Similarly, the exemplary nozzle 406 is off-center with respect to electrode 202, and in particular, the outer wall of nozzle 406 is aligned with central longitudinal axis 402 such that nozzle 406 is closer to gap 304. Stated differently, nozzle 406 is on the gap side of central longitudinal axis 402. The exemplary nozzle 404 is fluidly coupled to a flow lumen (not visible) in the electrode 200, which is fluidly coupled to an irrigation lumen in the handle 110 (FIG. 1), which is fluidly coupled to the peristaltic pump 124 (FIG. 1) and a source of saline. Thus, during use, saline exits from within the electrode 200 by the nozzle 404. Similarly, the exemplary nozzle 406 is fluidly coupled to a flow lumen (not visible) in the electrode 202, which is fluidly coupled to an irrigation lumen in the handle 110 (FIG. 1), which is fluidly coupled to the peristaltic pump 124 (FIG. 1) and a source of saline. Thus, during use, saline exits from within the electrode 202 by the nozzle 404.

[0045] FIG. 4B illustrates a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 4B-4B of FIG. 4A. In particular, the view of FIG. 4B is a mid-section view, and visible in FIG. 4B are electrodes 200 and 202. As previously discussed, electrodes 200 and 202 define gap 304. FIG. 4B better illustrates that each exemplary electrode is polygonal, and in particular, each electrode is a square with chamfered corners (e.g., chamfer 414). In the exemplary case of FIG. 4B, electrodes 200 and 202 are positioned about their respective central longitudinal axes such that interior-facing wall 416 of electrode 200 is parallel to interior-facing wall 418 of electrode 202, although other arrangements are possible.

[0046] Also visible in FIG. 4B are exemplary internal flow paths or flow lumens within each electrode. Referring initially to electrode 200, the flow lumen within electrode 200 comprises a blind bore 420 coaxial with central longitudinal axis 400. Blind bore 420 is referred to as "blind" in the sense that it is created in such a way that the bore opens at the proximal end of the electrode (e.g., fluidly connected to an irrigation lumen within handle 110 (FIG. 1)), but does not pass completely through electrode 200 (i.e., the bore does not create an aperture through contact surface 410). Additionally, although referred to as a bore, blind bore 420 may be created using any suitable method (e.g., boring, laser drilling, casting, and milling). At the nozzle level, the exemplary flow lumen within electrode 200 also comprises a through bore 422. Thus, the exemplary throughbore 422 defines a nozzle 404 as well as a nozzle 424 on an opposite side of the throughbore 422. The throughbore 422 may be made in any suitable manner, such as by boring, laser drilling, casting, and milling. In operation, saline flows along a flow lumen in the elongate shaft 106 (FIG. 4A), through the irrigation lumen of the handle 110 (FIG. 1), and then through the blind bore 420. The saline flow then splits into two streams at the intersection of the blind bore 420 and the throughbore 422, with each stream exiting the electrode 200 through a respective nozzle 404 or 424.

[0047] The exemplary throughbore 422 defines a central axis 426. The spray direction of nozzle 404 is coaxial with the central axis 426. Similarly, the spray direction of nozzle 424 is coaxial with the central axis 426, but in the exemplary case of FIG. 4B, the spray direction of nozzle 424 is in an opposite direction to the spray direction of nozzle 404. Stated another way, the angle between the spray direction of nozzle 404 and the spray direction of nozzle 424 is 180 degrees (°) as measured through gap 304, which angle is indicated by double-headed arrow 427.

[0048] Referring now to the electrode 202, the flow lumen within the electrode comprises a blind bore 428 coaxial with the central longitudinal axis 402. The blind bore 428 is referred to as "blind" for the same reasons discussed with respect to the electrode 200, and may be created using any suitable method. At the level of the nozzle, the exemplary flow lumen within the electrode 202 also comprises a through bore 430. The exemplary through bore 430 thus defines the nozzle 406, as well as a nozzle 432 on an opposite side of the through bore 430. The through bore 422 may likewise be created in any suitable manner. In operation, saline flows along the flow lumen within the elongate shaft 106 (FIG. 4A), through the fluid irrigation lumen of the handle 110 (FIG. 1), and then through the blind bore 428. The saline flow then splits into two streams at the intersection of blind bore 428 and through bore 430 , with each stream exiting the electrode 202 through a respective nozzle 406 or 432 .

[0049] The exemplary throughbore 430 also defines a central axis 434. The spray direction of nozzle 406 is coaxial with the central axis 434. Similarly, the spray direction of nozzle 432 is coaxial with the central axis 434, but in the exemplary case of FIG. 4B, the spray direction of nozzle 432 is in an opposite direction to the spray direction of nozzle 404. Stated another way, the angle between the spray direction of nozzle 406 and the spray direction of nozzle 432 is 180° as measured through gap 304. In the exemplary case of FIG. 4B, it follows that the locations of nozzles 406 and 432 are mirror images across gap 304 of the locations of nozzles 404 and 424, respectively.

[0050] The nozzle relationship in FIG. 4B is merely an example, and the angle between the nozzles of the electrodes may take many suitable forms. For example, referring to the electrode 200 as representative, the through bore 422 may be implemented as two separate bores that, in other cases, enter the electrode at an angle, but still intersect with the blind bore 420. When implemented in this manner, the angle between the nozzle 404 and the nozzle 424 may be less than 180°, in some cases 170° or less, in other cases 120° or less, in other cases 90° or less, and in still further cases 60° or less. Stated more geometrically, each bore may have a central axis, and the angle between the central axis of the first bore and the central axis of the second bore may be less than 180°, including any of the angles less than 180° given in this paragraph.

[0051] 4B, the angle for the nozzle may be equivalently indicated as the angle between the nozzle spray direction and an imaginary line intersecting the central longitudinal axis of the electrode. As an example, consider line 436 that covers both central longitudinal axis 400 and central longitudinal axis 402. Considered in this way, the angle between representative nozzle 404 and line 436 may be less than 90°, in some cases 85° or less, in other cases 60° or less, in other cases 45° or less, and in still further cases 30° or less. In one particular case of a single nozzle implemented on each electrode, the angle may be 0°. The description of nozzle 404 is equally applicable to nozzles 406, 424, and 432.

[0052] 4A and 4B simultaneously, for the exemplary electrode shown, the spray directions of nozzles 404, 424, 406, and 432 all lie in a common plane. When central longitudinal axes 400 and 402 are parallel, the common plane is also perpendicular to central longitudinal axes 400 and 402. However, in other cases, the spray directions of each nozzle need not be coplanar.

[0053] FIG. 4C shows a side elevational view of an electrode according to at least some embodiments. In particular, FIG. 4C shows a view of the electrode 200 facing the electrode 202, which is not visible. Also shown in FIG. 4C is the central longitudinal axis 400 of the electrode 200 with the central axis 426 in the exemplary case where the spray directions are coplanar. However, in still further embodiments, the spray directions need not be coplanar and may in fact be angled toward the distal end of the electrode. FIG. 4C shows lines 438 and 440, respectively, which represent alternative spray directions for nozzles 404 and 424 (FIGS. 4A and 4B). Equivalently stated, lines 438 and 440 represent the central axis of the electrode's bore, which defines the internal flow lumen and the corresponding nozzle. In the exemplary case, each of the spray directions represented by lines 438 and 440 forms an acute angle with respect to the central longitudinal axis 400, as shown by double-headed arrow 442, which opens toward the rounded contact surface of electrode 200. In some cases, and as shown, the angles are the same, while in other cases the angles may be different. Although electrode 202 is not visible in FIG. 4C, the spray angle associated with the nozzle of electrode 202 may form a similar acute angle with respect to the central longitudinal axis 402 of electrode 202.

[0054] FIG. 5A illustrates a front elevational view of a distal end of a device according to at least some embodiments. In particular, visible in FIG. 5A are an exemplary electrode 500 and an exemplary electrode 502. As previously discussed, the exemplary electrodes 500 and 502 are spaced apart from one another, thereby forming a gap 504. The electrodes 500 and 502 each have a rounded distal end or contact surface, which may be ellipsoidal or spheroidal. The exemplary electrodes 500 and 502 each define a central longitudinal axis 506 and 508, respectively. In the exemplary arrangement, the central longitudinal axes 506 and 508 are coplanar and parallel. However, in other cases, the central longitudinal axes 506 and 508 may be coplanar but not parallel.

[0055] Also shown in FIG. 5A are nozzles on each of the electrodes. In particular, visible in FIG. 5A are apertures or nozzles 510 exposed on the outer surface of electrode 500 and apertures or nozzles 512 exposed on the outer surface of electrode 502. The exemplary nozzle 510 is fluidly coupled to a flow lumen in electrode 200, which is fluidly coupled to an irrigation lumen in handle 110 (FIG. 1), which is fluidly coupled to a peristaltic pump 124 (FIG. 1) and a source of saline. Thus, during use, saline exits from within electrode 500 by nozzle 510. Similarly, the exemplary nozzle 512 is fluidly coupled to a flow lumen in electrode 202, which is fluidly coupled to an irrigation lumen in handle 110 (FIG. 1), which is fluidly coupled to a peristaltic pump 124 (FIG. 1) and a source of saline. Thus, during use, saline exits from within the electrode 502 by the nozzle 512 .

[0056] FIG. 5B illustrates a cross-sectional view of electrodes according to at least some embodiments taken substantially along line 5B-5B of FIG. 5A. In particular, visible in FIG. 5B are electrodes 500 and 502. As previously discussed, electrodes 500 and 502 define gap 504. FIG. 5B better illustrates that each exemplary electrode is polygonal, and in particular, each electrode is a square with chamfered corners (e.g., chamfer 514). In the exemplary case of FIG. 5B, electrodes 500 and 502 are centered about their respective central longitudinal axes such that interior-facing chamfer 514 of electrode 500 and interior-facing chamfer 516 of electrode 502 are bisected by line 519 extending between central longitudinal axes 506 and 508. Equivalently stated, flat side wall 540 of electrode 500 lies in a plane and flat side wall 542 lies in a plane, the planes forming a right angle.

[0057] Also visible in FIG. 5B are exemplary internal flow paths or flow lumens within each electrode. For example, electrode 500 defines a blind bore 518 coaxial with central longitudinal axis 506. Blind bore 518 may be created using any suitable method (e.g., boring, laser drilling, casting, and milling). At the nozzle level, the exemplary flow lumen within electrode 500 also includes bores 520 and 522. Exemplary bore 520 defines nozzle 510, and exemplary bore 522 defines nozzle 524. Bores 520 and 522 may be created in any suitable method (e.g., boring, laser drilling, casting, and milling). In operation, saline flows along the flow lumen within elongate shaft 106, through the irrigation lumen of handle 110 (FIG. 1), and then through blind bore 518. The saline flow then splits into two streams at the intersection of blind bore 518 with bores 520 and 522 , with each stream exiting electrode 500 through a respective nozzle 510 or 524 .

[0058] The exemplary bore 520 defines a central axis 526 and the spray direction of the nozzle 510 is coaxial with the central axis 526. The exemplary bore 522 defines a central axis 528 and the spray direction of the nozzle 524 is coaxial with the central axis 528. The angle between the spray direction of the nozzle 510 and the spray direction of the nozzle 524 is 90° or less, and in some cases 60° or less, as measured through the gap 504. The exemplary electrode 502 has a mirror set of components including a blind bore, a bore intersecting the blind bore, and a nozzle having a spray direction. The various components of the mirror set will not be specifically numbered and discussed to avoid unduly lengthening this specification.

[0059] 5B, the angle relative to the nozzle may be equivalently indicated as the angle between the nozzle's spray direction and a line 519 that intersects the central longitudinal axis of the electrode. Considered in this manner, the angle between the nozzle's spray direction and line 519 may be less than 45°, and in some cases may be 22.5° or less. In one particular case of a single nozzle implemented on each electrode, the angle may be 0° relative to line 519 (e.g., the spray direction may be coaxial with line 519). The description regarding nozzle 510 is equally applicable to nozzles 512, 524, and 530. The spray directions of nozzles 510 and 512 may all lie in a common plane, or in other cases may form an acute angle with respect to the central longitudinal axis 506 and open to a rounded contact surface. The spray directions of nozzles 512 and 530 may all lie in a common plane, or in other cases may form an acute angle with respect to central longitudinal axis 508 and open out into a rounded contact surface.

[0060] FIG. 6 shows both a front elevation view of an electrode as well as a cross-sectional view of the electrode, according to at least some embodiments. In particular, section 600 is a front elevation view of the electrode, and section 602 shows a cross-sectional view through the nozzle of the electrode of section 600. Many of the components and relationships of the electrode of FIG. 6 are the same as those discussed with respect to FIGS. 4A-4C and 5A-5B above, and will not be repeated here again so as not to unduly lengthen this specification. However, FIG. 6 shows that in cases where the chamfered corners face each other across the gap, the spray direction of the nozzle does not have to be perpendicular to the face of the electrode in which the nozzle is defined. In the exemplary case of FIG. 6, the angle between the spray directions (as measured through the gap) of the nozzles of the electrode may be 120° or less. Again, as shown, the spray directions are all coplanar.

[0061] FIG. 7 shows both a front elevation view of an electrode as well as a cross-sectional view of the electrode, according to at least some embodiments. In particular, portion 700 is a front elevation view of the electrode, and portion 702 shows a cross-sectional view through the nozzle of the electrode of portion 700. Many components and relationships of the electrode of FIG. 7 are the same as those discussed with respect to FIGS. 4A-4C and 5A-5B above, and will not be repeated here again so as not to unduly lengthen this specification. However, FIG. 7 clearly shows an exemplary situation in which the spray direction of the nozzle is angled downward toward the rounded contact surface. Stated differently, FIG. 7 shows an exemplary situation in which the spray direction forms an acute angle with the respective longitudinal central axis (not specifically shown), in some cases the acute angle is 60° or less, and in other cases the acute angle is 30° or less. Stated differently, the exemplary nozzle may form an angle of 30° or more from the horizontal, for example, and in other cases an angle of 60° or more from the horizontal.

[0062] FIG. 8A illustrates a front elevational view of the distal end of a device according to at least some embodiments. In particular, visible in FIG. 8A are an exemplary electrode 800 and an exemplary electrode 802. Many of the components and relationships of the electrodes of FIG. 8A (and FIG. 8B) are the same as those discussed with respect to FIGS. 4A-4C and 5A-5B above, and will not be repeated again here so as not to unduly lengthen this specification. As previously mentioned, the exemplary electrodes 800 and 802 are spaced apart from one another, thereby forming a gap 804. The exemplary electrodes 800 and 802 each have a rounded distal end or contact surface, each of which may be ellipsoidal or, in some cases, spheroidal.

[0063] Exemplary electrodes 800 and 802 each define a central longitudinal axis. In particular, electrode 800 defines a central longitudinal axis 806, and electrode 802 defines a central longitudinal axis 808. In the exemplary arrangement, central longitudinal axes 806 and 808 are coplanar and parallel. However, in other cases, central longitudinal axes 400 and 402 may be coplanar but not parallel. Also visible in FIG. 8A are nozzles on each of the electrodes. In particular, visible in FIG. 8A are apertures or nozzles 810 exposed on the outer surface of electrode 800 and apertures or nozzles 812 exposed on the outer surface of electrode 802. Exemplary nozzle 810 is fluidly coupled to a flow lumen in electrode 800. Similarly, exemplary nozzle 812 is fluidly coupled to a flow lumen in electrode 802.

[0064] FIG. 8B illustrates a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 8B-8B of FIG. 8A. In particular, FIG. 8B illustrates that the cross-sectional shape of the exemplary electrode need not be polygonal, and may in fact be in the form of a closed curve having at least one axis of symmetry. As shown, the cross-sectional shape is oval, specifically, elliptical, although other closed curve shapes may be implemented. Each exemplary ellipse has long walls, and in an embodiment, the long walls facing the gap 804 are parallel. Although FIG. 8B illustrates the angle between the spray directions of the nozzles to be approximately 90°, the spray directions of the nozzles may take any suitable angle, for example, 180° or less.

[0065] FIG. 9A shows a front elevational view of the distal end of a device according to at least some embodiments. In particular, visible in FIG. 9A are an exemplary electrode 900 and an exemplary electrode 902. Many of the components and relationships of the electrodes of FIG. 9A (and FIG. 9B) are the same as those discussed with respect to FIGS. 4A-4C and 5A-5B above, and will not be repeated here again so as not to unduly lengthen this specification. As previously mentioned, the exemplary electrodes 900 and 902 are spaced apart from one another, thereby forming a gap 904. The exemplary electrodes 900 and 902 each have a rounded distal end or contact surface, each of which may be ellipsoidal or, in some cases, spheroidal.

[0066] Exemplary electrodes 900 and 902 each define a central longitudinal axis. In particular, electrode 900 defines a central longitudinal axis 906, and electrode 902 defines a central longitudinal axis 908. In the exemplary arrangement, central longitudinal axes 906 and 908 are coplanar and parallel. However, in other cases, central longitudinal axes 906 and 908 may be coplanar but not parallel. Also visible in FIG. 9A are nozzles on each of the electrodes. In particular, visible in FIG. 9A are apertures or nozzles 910 exposed on the outer surface of electrode 900 and apertures or nozzles 912 exposed on the outer surface of electrode 902. Exemplary nozzle 910 is fluidly coupled to a flow lumen in electrode 900. Similarly, exemplary nozzle 912 is fluidly coupled to a flow lumen in electrode 902.

[0067] FIG. 9B shows a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 9B-9B in FIG. 9A. In particular, FIG. 9B illustrates that the cross-sectional shape of the exemplary electrode need not have two axes of symmetry. In the exemplary case, the cross-sectional shape is a polygon with chamfered corners, specifically a convex polygon with a smaller portion facing away from the gap 904. As shown, the smaller portion forms an angle of about 15° with a parallel tangent at the nozzle location. Stated differently, each electrode has a cross-sectional shape of a convex polygon with one axis of symmetry, which is parallel or coaxial with a line 914 connecting with the central longitudinal axis. The exemplary cross-sectional shape of FIG. 9B may help direct the flow of saline to the outer circumference of the electrode, aiding in the wetting process.

[0068] FIG 10A shows a front elevational view of an electrode according to at least some embodiments. FIG 10B shows a cross-sectional view of the electrode of FIG 10A according to at least some embodiments. FIG 10C shows a cross-sectional view of an electrode according to at least some embodiments in which the spray direction forms an acute angle with the central longitudinal axis of the electrode. FIG 10D shows a cross-sectional view of an electrode according to at least some embodiments taken substantially along line 10D-10D of FIG 10C.

[0069] 10A-10D simultaneously, in another exemplary embodiment, with reference to electrode 1000 as representative of both electrodes, electrode 1000 defines a single aperture or nozzle 1004 having a spray direction down toward tissue at a target site. In particular, electrode 1000 forms an angled surface 1006, and nozzle 1004 is aligned with angled surface 1006 such that fluid flow is directed along angled surface 1006 toward the center of electrode 1000 at distal surface 1008 to help control the direction of flow and ensure effective wetting of the distal surface. With respect to the horizontal surface 1010 (e.g., the horizontal surface 1010 forms a plane perpendicular to the central longitudinal axis of the electrode 1000), the angled surface 1006 is created at an angle α ranging between and including 90° and 120°, in some cases about 113°, and in other cases about 113°. The distal surface 1008 that contacts the tissue has a reduced surface area to reduce drag and improve movement across the tissue, e.g., an angle α of 113° provides a smaller contact surface area than an angle α of 90°. The exemplary electrode 1000 of FIG. 10B defines a centrally located bore 1012 and an offset bore 1014 that creates the nozzle 1004. Thus, the centrally located bore 1012 and the offset bore 1014 are parallel to each other and to the central longitudinal axis of the electrode 1000.

[0070] The exemplary electrode 1000 of Figure 10C defines a centrally located bore 1012 and an angled bore 1016 that creates the nozzle 1004. Thus, the centrally located bore 1012 and the angled bore 1016 form an angle therebetween. As shown in the embodiment of Figure 10C, the spray direction defined by the bore 1014 is angled away from the angled surface 1006 and away from the central longitudinal axis of the exemplary electrode 1000.

[0071] The spray direction defined by the nozzles of the embodiment of Figures 10A-10D may enhance device performance and reduce the risk of electrical bridging between electrodes by having the saline at the tip rather than from the side of the device. This may result in a more efficient use of energy, which in turn improves the tissue lesion created by the device. The saline also takes a more direct path to the distal end of the electrode, which may efficiently deliver the saline to the target tissue site, reduce tissue charring, improve migration over the tissue, and reduce the amount of saline used during the procedure. Additionally, less fluid at the target tissue site may increase visibility of the device, which may allow clinicians to be more confident in using the device and ultimately provide more precise treatment.

[0072] The distance D of the proximal end of the saline outlet from the tip of the device can range, for example, between and including 1.5-2.5 mm, in some cases about 1.75 mm, and in still other cases about 1.75 mm. This dimension is selected to ensure focused fluid delivery at the target tissue without being too close to the tissue so that the outlet would tend to become blocked.

[0073] The exemplary angled surface 1006 encourages passive flow of fluid toward the tip of the electrode 1000. The horizontal surface 1010 may be oriented parallel to the direction of movement of the device, i.e., into and out of the page in the view of FIG. 10A. The cuts that form the angled surface 1006 and horizontal surface 1010 result in a reduction in the surface area that contacts the tissue (compared to the fully rounded surface of the previous embodiment). The reduced surface area and parallel positioning of the ridges may enhance the movement of the device across the tissue. As a result, the device may create more uniform lesions when the device is used dynamically. The angled surface 1006 and horizontal surface 1010 may also increase control of movement, ensuring that the clinician can effectively control the size and depth of the lesion created.

[0074] FIG. 11A shows a side elevational view of an electrode according to at least some embodiments. In particular, FIG. 11A shows an electrode 1100 as viewed from within the gap between two electrodes. Many components and relationships of the electrode of FIG. 9A (and FIG. 9B) are the same as those discussed with respect to FIG. 8A and FIG. 8B and will not be repeated again here so as not to unduly lengthen this specification. The exemplary electrode 1100 defines two apertures or nozzles 1102 and 1104. Each nozzle 1102 and 1104 is associated with a trough or channel 1106 and 1108, respectively, that helps direct the flow of fluid toward the distal end of the electrode, improving tissue wetting and fluid delivery to the tissue at the target site. Considering the channel 1106 as representative, the channel 1106 intersects with the nozzle 1102, and the channel 1106 proceeds from the nozzle 1102 to the distal end of the electrode 1100. The channel 1106 has a closed bottom and an open top that intersects the outer surface of the electrode 1100. The channel 1106 defines a channel direction that is parallel to a central longitudinal axis (not specifically shown) of the electrode 1100, although in other cases the channel direction need not be parallel to the central longitudinal axis.

[0075] FIG. 11B shows a cross-sectional front elevation view of an electrode according to an exemplary embodiment. In particular, the cross-sectional view of FIG. 11B is taken parallel to the plane of the page of FIG. 11A and through one of the channels 1106 or 1108. Thus, visible in FIG. 11B is the electrode 1100 as well as the mating electrode 1110. As previously mentioned, the electrodes 1100 and 1110 define a gap 1112 therebetween. As discussed above, the nozzle 1102 as well as the corresponding nozzle 1114 define a spray direction into the gap 1112, and the angle between the spray directions of the nozzles of the same electrode may take any suitable angle. In use, not only is saline sprayed from the nozzle into the gap 1112, but a portion of the saline also bypasses and travels along the respective channels, such as the channel 1106 associated with the nozzle 1102 and the channel 1116 associated with the nozzle 1114. The flow of saline along the channels aids in wetting the distal surface of the electrode.

[0076] FIG. 12 illustrates a partial cross-sectional view of the device 104 according to at least some embodiments. In particular, FIG. 12 illustrates a cross-sectional view of a portion of the handle 110 and elongate shaft 106 (FIG. 1) of the device 104. In an exemplary embodiment, each electrode (not visible in FIG. 12) has a dedicated fluid delivery tube 1200 and 1202 formed from an electrically insulating material, such as nylon. Each electrode is supplied with saline by a respective fluid delivery tube 1200 or 1202 that extends along the length of the elongate shaft 106. Both fluid delivery tubes 1200 and 1202 fluidly couple to a single irrigation lumen 1204 in the handle 110. The fluid delivery tubes 1200 and 1202 extend the length of the elongate shaft 106 to the handle 110, thereby reducing the possibility of current bridging while saline is being delivered. However, depending on the conductivity of the saline and other factors (e.g., applied voltage), bifurcating the irrigation lumen 1204 may occur in any suitable location, such as closer to the electrode than to the handle (e.g., within the elongate shaft 106) or at the proximal edge of the electrode. In instances where a single fluid delivery tube extends along the elongate shaft 106, the single fluid delivery tube may extend along the exterior surface of the elongate shaft 106 or between the shaft (or spine-like element) and the sheath.

[0077] Considering again the embodiment in which the irrigation flow lumen 1204 is bifurcated in the handle 110, each fluid delivery tube 1200 and 1202 fluidly couples to a respective flow lumen in a respective electrode. In an exemplary case, the electrical conductivity between the two electrodes along the saline in the fluid delivery tubes 1200 and 1202 is lower than the electrical conductivity between the two electrodes in contact with tissue. That is, to avoid electrical energy traveling along the fluid delivery tubes, the length of the shunt path between the electrodes through the tubes 1200 and 1202 is made long enough to have a lower conductivity (when filled with saline) than the conductivity through the saline between the electrodes and / or through the tissue at the target site. The longer the fluid path through the two fluid delivery tubes, the longer the shunt path and the lower the electrical conductivity between the electrodes along the shunt path.

[0078] 12, in an exemplary case, energy delivery to the electrodes is via conductive tubes. FIG. 12 shows two conductive tubes, including conductive tube 1204 shown in cross section, and conductive tube 1206 (only partially visible at the proximal end). Conductive tubes 1206 and 1208 run parallel to one another and form a portion of elongated shaft 106. Each conductive tube is coupled to a respective conductor in flexible multi-conductor cable 142 (FIG. 1). Conductive tubes 1206 and 1208 extend along elongated shaft 106 from handle 110 to the electrodes. Disposed within each conductive tube 1206 and 1208 is a fluid delivery tube 1200 and 1202, respectively. In some cases, each fluid delivery tube is coaxial with its conductive tube, although such is not required.

[0079] The exemplary conductive tubes are physically separated, parallel, and electrically insulated from one another by a non-conductive spine 1210 that extends from the handle 110 to the electrode. The outer surfaces of the conductive tubes may be electrically insulated with a coating or sheath 1212 that covers the tubes and spine 1210. The sheath 1212 may form a single smooth outer surface of the elongate shaft 106. In an alternative embodiment, each conductive tube is individually insulated using a coating or sheath.

[0080] FIG. 13 shows a side elevational view of an electrode to discuss an exemplary connection between the electrode, the electrode conductive tube, and the spine, according to at least some embodiments. In particular, the electrode 1300 is representative of any of the electrodes discussed above. Proceeding progressively from left to right in the figure, the exemplary electrode 1300 includes a proximal boss 1302, an annular ring 1304, an annular trough 1306, and an exemplary exposed portion 1308. The boss 1302 has an outer diameter designed and constructed to freely expand and contract within the inner diameter of the conductive tube (e.g., tube 1206 in FIG. 12) and to be electrically coupled to the tube. Thus, the boss 1302 is received within the conductive tube, and the tube abuts against a shoulder 1308 created between the boss 1302 and the annular ring 1304. As will be described in more detail below, the spine 1210 (e.g., FIG. 12) terminates in lugs, each of which is coupled to a respective annular trough 1306 to hold the electrode 1300 in relationship to a respective conductive tube.

[0081] FIG. 14 illustrates a perspective view of a distal end of a device according to at least some embodiments. In particular, visible in FIG. 14 is an exemplary electrode 1300 with a mating electrode 1400. Also visible is an exemplary conductive tube 1206, as well as a conductive tube 1208 associated with the electrode 1400. Between the conductive tubes 1206 and 1208 is an exemplary spine 1210. In the arrangement of FIG. 14, a boss (not visible) of the electrode 1300 is freely telescopic within the conductive tube 1206, which abuts against a shoulder created by the annular ring 1304. Similarly, a boss (not visible) of the electrode 1400 is freely telescopic within the conductive tube 1208, which abuts against a shoulder created by the annular ring 1404. The exemplary spine 1210 terminates in the lugs 1406 and 1408. Lug 1406 is disposed within annular trough 1306 of electrode 1300. Similarly, lug 1408 is disposed within annular trough 1410 of electrode 1400. Lugs 1406 and 1408 not only help maintain spine 1210 in alignment with conductive tubes 1206 and 1208, but also help hold electrodes 1300 and 1400 in operative relationship with conductive tubes 1206 and 1208, respectively.

[0082] As discussed with respect to FIG. 1, in some cases, saline is provided to the electrodes by a peristaltic pump 124 (FIG. 1). A peristaltic pump is a displacement pump that provides a volumetrically controlled flow. However, peristaltic pumps deliver flow in pulses caused by the interaction of a rotating head against a stationary component, the pulses being referred to as fluid flow pulsatility. Coagulation is more uniform by reducing the fluid flow pulsatility from the peristaltic pump. The specification now turns to an exemplary system for reducing fluid flow pulsatility.

[0083] FIG. 15 shows a simplified cross-sectional view of a conductive tube, a fluid delivery tube, and electrodes, according to at least some embodiments. In particular, the arrangement of FIG. 15 is designed and constructed to reduce fluid flow pulsatility through the use of flow restrictors and compliant tubing. FIG. 15 shows an exemplary conductive tube 1500, which is representative of any of the conductive tubes discussed above. Disposed within the conductive tube 1500 is a fluid delivery tube 1502, which is representative of any of the fluid delivery tubes discussed above. According to these embodiments, the fluid delivery tube 1502 has an outer diameter that is smaller than an inner diameter of the conductive tube 1500, thereby forming an annular volume 1504 between the outer diameter of the fluid delivery tube 1502 and the inner diameter of the conductive tube 1500. In FIG. 15, the fluid delivery tube 1502 is shown as being coaxial with the central longitudinal axis of the conductive tube 1500, however, in some cases the fluid delivery tube may be leaned against the inner diameter under the force of gravity, particularly under the weight of saline flowing within the inner diameter of the fluid delivery tube 1502.

[0084] Disposed on the distal end of the conductive tube 1500 is an electrode 1506, which is representative of any of the electrodes discussed above. Fluidly disposed between the fluid delivery tube 1502 and a flow lumen in the electrode 1506 is a flow restrictor 1508. The flow restrictor 1508 may take any suitable form, such as an orifice or an irregular path device. In some cases, the flow restrictor 1508 is a separate element that is physically disposed between the fluid delivery tube 1502 and the flow lumen of the electrode 1506. In still other cases, the flow restrictor 1508 may be implemented on another component, such as a boss of the electrode (e.g., boss 1302 of FIG. 13). Placing the flow restrictor 1508 in the saline path increases the resistance to flow and increases the back pressure. The fluid delivery tube 1502, upstream of the flow restrictor 1508, is made from compliant tubing. The compliance of the fluid delivery tube 1502 acts to dampen the pulses generated by the upstream peristaltic pump: the outer diameter of the fluid delivery tube 1502 expands and contracts within the annular volume 1504, providing a pressure damping behavior.

[0085] In still other cases, the flow restrictor 1508 may be implemented by a portion of the fluid delivery tube 1502 itself. For example, a portion of the fluid delivery tube 1502 may be implemented in the form of a rigid or non-compliant tube having a reduced inside diameter. The rigid or non-compliant portion may be fluidly disposed in front of or upstream of the electrode 1506. In these cases, the compliance of the upstream portion of the fluid delivery tube 1502 and / or the compliance of the flexible tubular member 122 (FIG. 1) may provide a fluid pressure dampening aspect.

[0086] FIG. 16 illustrates a simplified cross-sectional view of a portion of a fluid delivery tube according to at least some embodiments. In particular, FIG. 16 illustrates a fluid delivery tube 1600, which is representative of any of the fluid delivery tubes discussed above. The fluid delivery tube 1600 comprises a first tube section 1602 fluidly coupled to a second tube section 1604. In the exemplary system, the first tube section 1602 has an inner diameter and the second tube section 1604 has an inner diameter smaller than the inner diameter of the first tube section 1600, thereby forming a flow restrictor. As shown, the second tube section 1604 has an outer diameter smaller than the inner diameter of the first tube section 1602. The first tube section 1602 is freely telescopically extended over the second tube section 1604 and held in place by an annular stopper 1606. The annular stopper 1606 presses the second tube section 1604 coaxially with the first tube section 1602, thereby forming an annular volume 1608 between the inner diameter of the first tube section 1602 and the outer diameter of the second tube section 1604.

[0087] As saline is pumped into fluid delivery tube 1600, it traps air within annular volume 1608. The trapped air creates an air pillow within annular volume 1608. The air pillow compresses with the pulse, thus acting to provide a pressure decay aspect.

[0088] Various embodiments may also include the option of aspirating fluid from the treatment site in addition to fluid delivery. Aspirated fluids may include saline, blood, and / or smoke generated during clotting. Removing blood may aid in locating the source of bleeding. Removing smoke may aid in visualization of the target site. Removing saline may help reduce excess saline pooling around the electrodes, which could potentially waste energy and reduce energy going into the tissue to coagulate it.

[0089] FIG. 17 shows a perspective view of the distal end of the device according to at least some embodiments. In particular, FIG. 17 shows the exemplary electrodes 1300 and 1400, the conductive tubes 1206 and 1208, the spine 1210, and the lugs 1406 and 1408 disposed within the respective annular grooves. FIG. 17 also shows an exemplary device that may define a suction aperture 1700 disposed between the two electrodes 1300 and 1400. The suction aperture 1700 may be on the side of the distal end of the device that faces the tissue of the target site, or may be biased toward the side so that the suction aperture 1700 is closer to the tissue to better aspirate blood and saline. Alternatively, placing the suction aperture 1700 or an additional suction aperture on the opposite side, away from the tissue of the target site, would primarily remove smoke.

[0090] The suction aperture 1700 may have a single inlet port or multiple inlet ports fluidly coupled together. Using multiple inlets may be beneficial to maintain suction flow if one of the inlet ports becomes clogged. Potential clogs are unlikely to be caused by tissue debris, since clots tend not to form debris, but clotted blood may clog the inlets.

[0091] The exemplary suction aperture 1700 may extend along the elongated shaft 106 and be fluidly connected to a fluid transport device including a tube or conduit that may be fluidly connected to a vacuum source. In one exemplary embodiment, the suction conduit may be defined within the spine 1210. Vacuum pressure control or siphoning may be implemented to limit the force of the vacuum. Although suction may remove some saline from the target site and electrode area, not all of the saline may be removed from the electrode area as a dry electrode surface will reduce coagulation performance and trigger the need to re-wet the electrode prior to applying energy. Additionally, when suction and delivery are operated concomitantly, suction may be controlled to reduce the withdrawal of saline delivered directly from the nozzle into the suction aperture. This may increase the chance of electrical bridging between the electrodes and again, insufficient coating of the electrode with saline, affecting coagulation. Preferably, the suction aperture should be spaced 5-8 mm proximally from the electrode tip and 3-5 mm away from the delivery aperture.

[0092] In another instance, suction apertures may be disposed adjacent to or through the outer lateral portions of each electrode. Removing fluid from the outer portions of the electrodes may help maintain tissue effect directly between the electrodes and reduce thermal diffusion laterally or radially away from the gap between the two electrodes.

[0093] In an exemplary case, suction can be selectively controlled; that is, saline delivery can be in operative communication with the coagulation controller 116 (FIG. 1) such that saline is delivered concomitantly with energy delivery, while suction can be more selectively controlled as a clinician's choice. Advantageously, selective control of suction can replace the need for a separate suction tool used during surgery, reducing the cost of the procedure. Selective suction control can be by a movable valve, or the speed of a pump, for example, an additional peristaltic pump. Control can be in communication with a button on a handle (not shown) or a foot switch.

[0094] FIG. 19 shows a perspective view of the device according to at least some embodiments. In particular, FIG. 19 shows the device 104, which includes electrodes 1300 and 1400, elongated shaft 106, handle 110, button 148, flexible multi-conductor cable 112, and flexible tubular member 122. Also shown in FIG. 19 is an exemplary suction portion 1900. The exemplary suction port 1900 is fluidly coupled to a suction lumen 1902. Both the suction port 1900 and the suction lumen 1902 are fluidly coupled to a suction transport conduit (not visible) that runs along the length of the elongated shaft 106 and within the handle 110. The suction lumen 1902 may be fluidly coupled to a vacuum source, such as a peristaltic pump or wall suction provided in the patient's room. The clinician selectively controls suction by moving a finger to cover and uncover the suction port 1900. During operation, when the suction port 1900 is uncovered, suction through the suction inlet at the distal end 108 of the device 104 is absent or reduced. Selective control, as opposed to constant suction, reduces the chance of clogging the suction lumen by limiting suction to times chosen by the clinician. The suction port 1900 can be selectively covered during energy delivery to control and tailor the desired tissue effect. The specification now turns to considerations regarding control of the rate or invasiveness of coagulation.

[0095] The rate or invasiveness of coagulation may be controlled based at least in part on the energy delivered to the electrode. In some cases, the clinician chooses the applied voltage setting as the coagulation energy setting. In an exemplary range of applied voltage settings between and including 110 volts (V) and 200V, the 110V setting may be a lower coagulation energy setting and the 200V setting may be a higher coagulation energy setting. Changing the applied voltage setting changes the RF voltage applied to the electrode from about 120V RMS to about 165V RMS. The higher the applied voltage setting, the higher the applied voltage, and the more tissue around the electrode is affected, for example, deeper and wider, by faster drying and more volume of the treated tissue.

[0096] In this regard, consider again the activation of button 150 (FIG. 1). Activation of button 150 can deliver energy to tissue according to the applied voltage setting selected by the clinician. When activated, MAX button 152 provides energy output at a level higher than the applied voltage setting to increase coagulation. MAX button 152 can automatically communicate with the controller to deliver RF output voltage to the electrode at a higher voltage level, such as the upper limit of the applied voltage range (e.g., 165V). Alternatively, activation of MAX button 152 can increase the applied voltage by a percentage of the applied voltage setting, a fixed value, or a fixed number of settings higher than the selected value. For example, if the applied voltage setting is 120V, activation of button 152 can communicate with the controller to deliver a voltage 30V higher or 30% higher.

[0097] In addition to giving the clinician the ability to select from a range of applied voltage settings (and thus a range of applied energies), according to an exemplary embodiment, the clinician may also choose from multiple flow rate settings for the saline solution. In an exemplary embodiment, the clinician may select from three or more flow rate settings, and in some cases, five flow rate settings. Each flow rate setting determines the flow of saline solution during use at each applied voltage setting. A higher applied voltage may vaporize a portion of the fluid being delivered, and thus, an increased flow rate may be achieved at the higher applied voltage setting to balance the vaporization and maintain a more consistent fluid coating around the electrode. To ensure that a suitable range of flows is provided, the coagulation controller 116 may automatically adjust the flow rate as a function of the applied voltage setting.

[0098] FIG. 20 illustrates a graph of applied voltage versus pump speed, according to at least some embodiments. In particular, the vertical axis illustrates applied voltage in voltage RMS, from 120V on the low end to 165V on the high end, in 5V increments. The range of applied voltage from 120V to 165V in 5V increments can be correlated to a range of applied voltage settings from 110V to 200V in 10V increments. However, in other cases, the numerical values ​​of applied voltage settings can be directly correlated to applied voltage. The horizontal axis illustrates the pump speed of the peristaltic pump in revolutions per second (RPS). Insofar as the pump speed of the peristaltic pump is directly related to flow rate, the horizontal axis can equally be considered to represent flow rate. In the exemplary graph, five separate flow rates are illustrated, representing five separate flow rate settings. Thus, the graph illustrates a system in which a clinician can choose from one of ten applied voltage settings and one of five flow rate settings to perform coagulation using those settings.

[0099] In the embodiment illustrated by FIG. 20, the selected flow rate setting results in a single flow rate for a range of applied voltages, but less than all applied voltages. As an example, consider flow rate 2. Exemplary flow rate 2 provides a peristaltic pump speed of just over 0.35 RPS for all applied voltages, including 120V to 150V. However, at a threshold applied voltage (155V in the embodiment), the pump speed, and therefore the flow rate, is increased to ensure proper wetting of the electrodes. Contrary to what the graph in FIG. 20 may imply, the exemplary system does not achieve mathematically linear flow control between any two applied voltages. Rather, the clinician can select an applied voltage in 5V increments (by choosing an applied voltage setting in 10V increments), followed by a step change in saline flow rate at the threshold voltage. Considering an exemplary flow rate of 2, at an applied voltage of 150 V, the pump speed is just over 0.35 RPS, and at an applied voltage of 155 V, the pump speed is just over 0.45 RPS. In the exemplary system, the clinician cannot select an applied voltage setting that results in an applied voltage between 150 V and 155 V, and therefore there is no intermediate pump speed setting between 150 V and 155 V. However, in other cases, as the number of applied voltages (and applied voltage settings) increases, linear interpolation to the pump speed is possible.

[0100] According to an exemplary embodiment, the applied voltage is controlled in an open loop notion. That is, the clinician chooses an applied voltage setting, which results in an applied voltage at an expected impedance between the electrodes. However, changes in the actual impedance between the electrodes will affect the applied voltage. For example, applying energy to the electrodes when they are held in air (e.g., higher impedance) may result in a higher applied voltage at the electrodes. Conversely, applying energy to the electrodes when the saline is electrically bridging, and thus shunting or shorting, the electrodes (e.g., lower impedance) may result in a lower applied voltage. In some embodiments, the coagulation controller 116 does not attempt to compensate for changes in impedance, but rather, based on the applied voltage setting, the coagulation controller operates in a manner that produces an applied voltage at an expected impedance, but the operation does not change as the actual impedance varies around the expected impedance.

[0101] Similarly, in exemplary embodiments, the peristaltic pump speed is controlled in an open-loop notion. That is, the clinician chooses a pump speed setting, which results in a pump speed (and thus a flow rate). Changes in applied voltage (e.g., caused by impedance variations) do not change the pump speed. That is, in some embodiments, the coagulation controller 116 does not attempt to compensate the pump speed for changes in actual applied voltage caused by impedance variations. However, intentionally increasing the applied voltage, such as by activating the MAX button 152, may correspondingly increase the pump speed. In exemplary embodiments, the coagulation controller 116 achieves flow control as a function of applied voltage, as shown in FIG. 20, through the use of a lookup table. The coagulation controller 116 receives an applied voltage or applied voltage setting, receives a flow rate setting, and performs a lookup in the lookup table to select a pump speed accordingly.

[0102] 21 illustrates in block diagram form an exemplary coagulation controller 116 according to at least some embodiments. In particular, the exemplary coagulation controller 116 has a control system 2100 coupled to various internal and external components. In the exemplary system of FIG. 21, the control system 2100 takes the form of a microcontroller having a processor 2102 electrically coupled to a random access memory (RAM) 2104, a read only memory (ROM) 2106, a digital to analog (D / A) output 2108, an analog to digital (A / D) input 2110, a digital input (D / I) 2112, as well as a section of communication logic (COM) 2114. Although the control system 2100 is shown in the form of a microcontroller, in other cases, individual components (i.e., individual processors, RAM, ROM, etc.) can be combined to implement the functionality, or other devices such as field programmable gate arrays (FGPAs), application specific integrated circuits (ASICs), programmable logic controllers (PLCs), programmable logic devices (PLDs), etc., and separate components can be used in place or in addition to the components described. The exemplary RAM 2104 can be the working memory of the processor 2102. The ROM 2106 can store programs and data in a non-volatile manner, and the processor 2102 can copy programs and data from the ROM 2106 to the RAM 2104 during program execution. In some cases, the ROM 2106 is a long-term storage location for a look-up table that relates applied voltage to a flow rate setting to control the peristaltic pump speed, and thus the look-up table can also be copied to the RAM 2104 during operation. The digital-to-analog output 2108 may be used to provide analog signals to other devices within the coagulation controller 116, such as a pump motor speed controller 2116 (discussed further below) and an RF voltage generator 2118. The analog-to-digital input 2110 may provide the control system 2100 with the ability to read analog signals.The digital input 2112 may be used to receive information to the control system 2100, such as information from the foot pedal device 138 / 140, the button 134 of the coagulation controller 116, or the button 148 on the device 104. Finally, the communication logic 2114 may be used for packet-based communication with internal or external devices (e.g., the interface device 132, or as an alternative means for communicating with the pump motor speed controller 2116).

[0103] The RF voltage generator 2118 defines a first connection or first lead 2120 that couples to a first terminal 2122 (e.g., an electrical pin) of the controller connector 118. In use, an electrical pin 2124 of the probe connector 114 couples the first terminal 2122 to a first electrode on the distal end of the device 104 (FIG. 1). Similarly, the RF voltage generator 2118 defines a second connection or second lead 2126 that couples to a second terminal 2128 (e.g., an electrical pin) of the controller connector 118. In use, an electrical pin 2131 of the probe connector 114 couples to another electrode on the distal end of the device 104.

[0104] The RF voltage generator 2118 is configured to generate coagulation energy at a coagulation frequency. According to an exemplary embodiment, the coagulation frequency generated by the RF voltage generator 2118 may be about 5 kHz to 20 MHz, in some cases about 30 kHz to 2.5 MHz, in other cases about 50 kHz to 500 kHz, and in certain cases about 100 kHz. As discussed above, the coagulation voltage may be between and including 120V to 165V RMS. In the exemplary system shown, the generated RF voltage 2118 receives instructions via a digital-to-analog output 2108, although the RF voltage generator 2118 may be provided with instructions in any suitable form, such as digitally (e.g., via a digital output, not specifically shown) or via packet-based messages (e.g., via the communication logic 2114).

[0105] The coagulation controller 116, and specifically the control system 2100, may implement control of the coagulation, including control of applied voltage and peristaltic pump speed. With respect to pump speed, the exemplary coagulation controller 116 implements a motor speed controller 2130 coupled to a motor 2132, by which the peristaltic pump 124 is turned. The motor 2132 may take any suitable form. For example, the motor 2132 may be a DC electric motor, whereby the motor speed controller 2130 provides a DC voltage to the electric motor that controls the speed of the output shaft. In other cases, the motor 2132 may be an AC electric motor, whereby the motor speed controller 2130 provides an AC voltage at a variety of voltages and frequencies that control the speed of the output shaft. In still other cases, the motor 2132 may be an air motor, whereby the motor speed controller 2130 provides air at a variety of pressures, which controls the speed of the output shaft. Thus, regardless of the type of motor 2132 implemented, the motor speed controller 2130 controls the speed of the motor in response to commands provided from the control system 2100. In the exemplary system, the commands to the motor speed controller 2130 are shown to be analog signals, but in other cases the motor speed controller 2130 may receive the commands in any suitable form, such as digitally (e.g., by a digital output, not specifically shown) or in packet-based messages (e.g., via the communications logic 2114). Finally, while the motor 2132 is shown to be directly coupled to the peristaltic pump 124, in other cases various gears and / or belts may be used to transfer the rotational motion of the shaft of the motor 2132 to the peristaltic pump 124. FIG. 21 is based on having a rotary peristaltic pump, however, one of ordinary skill in the art, with the benefit of this disclosure, can modify the system to be used with other types of outflow pumps, such as linear peristaltic pumps or centrifugal pumps in combination with a flow measurement device (as the flow rate through a centrifugal pump is not directly related to speed as it is with positive displacement pumps (such as peristaltic pumps)).

[0106] It is noted that while the embodiment of Figure 21 shows the peristaltic pump 124 as an internal or integral device with the coagulation controller 116 (e.g., within the same enclosure), in other cases the peristaltic pump 124 may be an external component to the coagulation controller 116. Additionally, while Figure 21 shows only one set of connected pump motor speed controllers, motors, and peristaltic pumps, the coagulation controller may implement more than one (e.g., a second pump to control suction).

[0107] Thus, in an exemplary embodiment, the control system 2100 comprises a RAM 2104 and a ROM 2106 (and possibly other non-transitory storage media) that store instructions implementing the coagulation control strategies discussed above. Exemplary instructions, when executed by the processor, can cause the coagulation controller to apply RF energy between the first and second electrodes and simultaneously flow saline through the electrodes of the device 104. Other exemplary instructions, when executed by the processor 2102, can cause the coagulation controller to accept instructions for a flow rate setting from a plurality of flow rate settings, accept instructions for an applied voltage setting, provide energy to the electrodes at a range of voltages determined by the applied voltage setting, where the energy provided varies over time as a function of the impedance experienced between the first and second electrodes, and simultaneously pump the conductivity, where the flow rate is selected by the coagulation controller from a table of applied voltage settings and flow rate settings, where the flow rate remains constant as the energy provided varies over time.

[0108] The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. [Additional note 1] 1. A method of operating an electrosurgical coagulation device, the method comprising: simultaneously applying radio frequency (RF) energy between a first electrode and a second electrode, the first electrode defining a first longitudinal axis, the second electrode defining a second longitudinal axis coplanar with the first longitudinal axis, and the first electrode and the second electrode defining a gap; simultaneously flowing a conductive fluid through a first nozzle and a second nozzle of the first electrode, the first nozzle defining a first spray direction and the second nozzle defining a second spray direction, a first angle between the first spray direction and the second spray direction being less than or equal to 180 degrees as measured through the gap; and flowing a conductive fluid through a third nozzle and a fourth nozzle of the second electrode, wherein the third nozzle defines a third spray direction and the fourth nozzle defines a fourth spray direction, and a second angle between the third spray direction and the fourth spray direction is less than or equal to 180 degrees as measured through the gap. [Additional note 2] the first angle is at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less; 2. The method of claim 1, wherein the second angle is at least one angle selected from the group consisting of 170° or less, 120° or less, 90° or less, and 60° or less. [Additional note 3] 2. The method of claim 1, further comprising an orientation of the first nozzle and the second nozzle, the first nozzle and the second nozzle being mirror images across the gap of the locations of the third nozzle and the fourth nozzle, respectively. [Additional note 4] 2. The method of claim 1, wherein the first spray direction, the second spray direction, the third spray direction, and the fourth spray direction exist in a common plane. [Additional note 5] Flowing the conductive fluid through the first nozzle and the second nozzle further includes flowing the first spray direction and the second spray direction forming a first acute angle with respect to the first longitudinal axis, the first acute angle opening toward a target tissue; 2. The method of claim 1, wherein flowing the conductive fluid through the third nozzle and the fourth nozzle further includes flowing the conductive fluid with the third spray direction and the fourth spray direction forming a second acute angle with respect to the second longitudinal axis, the second acute angle opening toward the target tissue. [Additional note 6] contacting a target tissue with a rounded contact surface of the first electrode; 2. The method of claim 1, further comprising contacting the target tissue with a rounded contact surface of the second electrode. [Additional note 7] 7. The method of claim 6, wherein the rounded contact surface of the first electrode is an ellipsoid and the rounded contact surface of the second electrode is an ellipsoid. [Additional note 8] 7. The method of claim 6, wherein the rounded contact surface of the first electrode is spheroidal and the rounded contact surface of the second electrode is spheroidal. [Additional note 9] Applying RF energy receiving, at a controller of the electrosurgical coagulation device, an indication of a flow rate setting from a plurality of flow rate settings; receiving, at the controller, an instruction to set an applied voltage; providing energy to the first electrode and the second electrode at a range of voltages determined by the applied voltage setting, the provided energy varying over time as a function of impedance experienced between the first electrode and the second electrode; and simultaneously providing 2. The method of claim 1, further comprising pumping the conductive fluid from the first nozzle to the fourth nozzle, wherein the flow rate is selected by the controller from a table of applied voltage settings and flow rate settings, and wherein the flow rate remains constant as the provided energy changes over time. [Additional Note 10] 2. The method of claim 1, wherein the first longitudinal axis is parallel to the second longitudinal axis. [Additional Note 11] 1. An electrosurgical device comprising: a handle having an irrigation lumen disposed therein; a cable coupled to a proximal end of the handle, the cable defining a first electrical conductor and a second electrical conductor; an elongate shaft coupled to the handle and defining a distal end opposite the handle; a first electrode disposed on the distal end of the elongate shaft and electrically coupled to the first electrical conductor, the first electrode defining a rounded contact surface opposite the distal end of the elongate shaft, a non-circular intermediate cross-section, and a first longitudinal axis; a second electrode disposed on the distal end of the elongate shaft and electrically coupled to the second electrical conductor, the second electrode defining a rounded contact surface opposite the distal end of the elongate shaft, a non-circular intermediate cross-section, and a second longitudinal axis coplanar with the first longitudinal axis; a first nozzle defined by the first electrode, the first nozzle being fluidly coupled to the irrigation lumen, the first nozzle defining a first spray direction between and including an angle (°) of 0° and 90° with respect to a line intersecting both the first longitudinal axis and the second longitudinal axis; a second nozzle defined by the second electrode, the second nozzle fluidly coupled to the irrigation lumen, the second nozzle defining a second spray direction between and including 0° and 90° relative to the line. [Additional Note 12] a third nozzle defined by the first electrode, the third nozzle fluidly coupled to the irrigation lumen, the third nozzle defining a third spray direction, the first spray direction and the third spray direction defining a first angle bisected by the line, the first angle being less than or equal to 180 degrees; and a fourth nozzle defined by the second electrode, the fourth nozzle fluidly coupled to the irrigation lumen, the fourth nozzle defining a fourth spray direction, the second spray direction and the fourth spray direction defining a second angle bisected by the line, the second angle being less than or equal to 180 degrees. [Additional Note 13] the first angle is 180°, the first nozzle is on the gap side of the first longitudinal axis, and the third nozzle is on the gap side of the first longitudinal axis; 13. The electrosurgical apparatus of claim 12, wherein the second angle is 180 degrees, the second nozzle is on the gap side of the first longitudinal axis, and the fourth nozzle is on the gap side of the first longitudinal axis. [Additional Note 14] the first angle is at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less; The electrosurgical apparatus of claim 12, wherein the second angle is at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less. [Additional Note 15] 15. The electrosurgical device of claim 14, further comprising an orientation of the first nozzle and the third nozzle, the first nozzle and the third nozzle being mirror images across the gap between the first electrode and the second electrode of the locations of the second nozzle and the fourth nozzle, respectively. [Additional Note 16] 13. The electrosurgical device of claim 12, wherein the first spray direction, the second spray direction, the third spray direction, and the fourth spray direction exist within a common plane. [Additional Note 17] the first spray direction and the third spray direction form a first acute angle with respect to the first longitudinal axis, the first acute angle opening toward the rounded contact surface of the first electrode; and 13. The electrosurgical device of claim 12, further comprising: the second spray direction and the fourth spray direction form a second acute angle with respect to the second longitudinal axis, the second acute angle opening toward the rounded contact surface of the second electrode. [Additional Note 18] 12. The electrosurgical apparatus of claim 11, wherein the rounded contact surface of the first electrode is ellipsoidal and the rounded contact surface of the second electrode is ellipsoidal. [Additional Note 19] 12. The electrosurgical apparatus of claim 11, wherein the rounded contact surface of the first electrode is spheroidal and the rounded contact surface of the second electrode is spheroidal. [Additional Note 20] 12. The electrosurgical device of claim 11, wherein the first electrode is rigidly coupled to the elongate shaft and is immovable relative to the second electrode, and the second electrode is rigidly coupled to the elongate shaft and is immovable relative to the first electrode. [Additional Note 21] 12. The electrosurgical apparatus of claim 11, wherein a line between an apex of the rounded contact surface of the first electrode and an apex of the rounded contact surface of the second electrode is perpendicular to the first longitudinal axis of the first electrode. [Additional Note 22] 12. The electrosurgical apparatus of claim 11, wherein the first electrode and the second electrode each have a polygonal cross-section. [Additional Note 23] 23. The electrosurgical apparatus of claim 22, wherein the first electrode and the second electrode each have a square cross-section. [Additional note 24] 12. The electrosurgical device of claim 11, wherein the first electrode and the second electrode each have a square cross-section with chamfered corners. [Additional note 25] 12. The electrosurgical apparatus of claim 11, wherein the second longitudinal axis is parallel to the first longitudinal axis.

Claims

1. a handle having an irrigation lumen disposed therein; a cable coupled to a proximal end of the handle, the cable defining a first electrical conductor and a second electrical conductor; an elongate shaft coupled to the handle and defining a distal end opposite the handle; a first electrode disposed on the distal end of the elongate shaft and electrically coupled to the first electrical conductor, the first electrode defining a rounded contact surface opposite the distal end of the elongate shaft, a non-circular intermediate cross-section, and a first longitudinal axis; a second electrode disposed on the distal end of the elongate shaft and electrically coupled to the second electrical conductor, the second electrode defining a rounded contact surface opposite the distal end of the elongate shaft, a non-circular intermediate cross-section, and a second longitudinal axis coplanar with the first longitudinal axis; a first nozzle defined by the first electrode, the first nozzle fluidly coupled to the irrigation lumen, the first nozzle defining a first spray direction with respect to a line intersecting both the first longitudinal axis and the second longitudinal axis that is greater than or equal to 0 degrees and less than or equal to 90 degrees; a second nozzle defined by the second electrode, the second nozzle fluidly coupled to the irrigation lumen, the second nozzle defining a second spray direction between 0° and 90° relative to the line; Equipped with the first spray direction forms a first acute angle with respect to the first longitudinal axis, the first acute angle opening toward the rounded contact surface of the first electrode; The electrosurgical device, wherein the second spray direction forms a second acute angle with respect to the second longitudinal axis, the second acute angle opening toward the rounded contact surface of the second electrode.

2. a third nozzle defined by the first electrode, the third nozzle fluidly coupled to the irrigation lumen, the third nozzle defining a third spray direction, the first spray direction and the third spray direction defining a first angle bisected by the line, the first angle being less than or equal to 180°; 2. The electrosurgical device of claim 1, further comprising: a fourth nozzle defined by the second electrode, the fourth nozzle fluidly coupled to the irrigation lumen, the fourth nozzle defining a fourth spray direction, the second spray direction and the fourth spray direction defining a second angle bisected by the line, the second angle being less than or equal to 180 degrees.

3. the first angle is 180°, the first nozzle is on a gap side of the first longitudinal axis, and the third nozzle is on the gap side of the first longitudinal axis; The electrosurgical apparatus of claim 2, wherein the second angle is 180 degrees, the second nozzle is on the gap side of the first longitudinal axis, and the fourth nozzle is on the gap side of the first longitudinal axis.

4. the first angle is at least one angle selected from the group including 170° or less, 120° or less, 90° or less, and 60° or less; The electrosurgical apparatus of claim 2, wherein the second angle is at least one angle selected from the group including less than or equal to 170°, less than or equal to 120°, less than or equal to 90°, and less than or equal to 60°.

5. The electrosurgical device of claim 4 , wherein the locations of the first and second nozzles are axisymmetric about the line of the locations of the third and fourth nozzles.

6. The third spray direction forms a third acute angle with respect to the first longitudinal axis, the third acute angle opening toward the rounded contact surface of the first electrode; The electrosurgical device according to claim 2, wherein the fourth spray direction forms a fourth acute angle with respect to the second longitudinal axis, the fourth acute angle opening toward the rounded contact surface of the second electrode.

7. The electrosurgical apparatus of claim 1 , wherein the rounded contact surface of the first electrode is ellipsoidal and the rounded contact surface of the second electrode is ellipsoidal.

8. The electrosurgical apparatus of claim 1 , wherein the rounded contact surface of the first electrode is spheroidal and the rounded contact surface of the second electrode is spheroidal.

9. 2. The electrosurgical device of claim 1, wherein the first electrode is rigidly coupled to the elongate shaft and is stationary relative to the second electrode, and the second electrode is rigidly coupled to the elongate shaft and is stationary relative to the first electrode.

10. 2. The electrosurgical device of claim 1, wherein a line between an apex of the rounded contact surface of the first electrode and an apex of the rounded contact surface of the second electrode is perpendicular to the first longitudinal axis of the first electrode.

11. The electrosurgical device of claim 1 , wherein the first electrode and the second electrode each have a polygonal cross-section.

12. The electrosurgical apparatus according to claim 11 , wherein the first and second electrodes each have a square cross-section.

13. The electrosurgical device of claim 1 , wherein the first and second electrodes each have a square cross-section with chamfered corners.

14. The electrosurgical apparatus of claim 1 , wherein the second longitudinal axis is parallel to the first longitudinal axis.

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