Arthroscopic resection probe

Abstract

A combination arthroscopic tissue resection probe is disclosed, including an elongate shaft having an outer conductive sleeve and an inner sleeve. Each sleeve has a distal region with a cutting window, and the inner sleeve is rotatable for cutting tissue. The outer surface of the outer sleeve distal region supports a ceramic body (580) and an electrode (570). The active electrode (570) defines two portions angularly offset from one another, including a first portion (571) extending circumferentially and axially along the tubular distal end and a second portion (578) extending from the distal end of the first portion across the tubular distal end, the second portion having at least one flange (595) configured to engage a notch (581) in the electrically insulating spacer (580) to resist separation of the active electrode from the electrically insulating spacer (580). The electrode, ceramic body, and outer sleeve each define a first suction (572, 586, 512) opening for aspirating fluid ablation byproducts into the interior of the shaft. Various methods of improved electrode attachment are disclosed that provide a low-profile probe distal tip while maintaining electrosurgical functionality.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and incorporates by reference in its entirety U.S. Provisional Patent No. 63 / 107,766, filed October 30, 2020, and U.S. Provisional Patent No. 63 / 223,651, filed July 20, 2021, both entitled "ARTHROSCOPIC RESECTION PROBE."

[0002] The present disclosure relates to surgical devices and associated methods for resecting tissue, and more particularly to a system for use in arthroscopic surgery that includes a powered handheld instrument coupled to a mechanical cutting blade integral with an electrosurgical assembly for ablating, cutting, or coagulating tissue. [Background technology]

[0003] Electrosurgical systems are used by physicians to perform specific functions during surgical procedures. For example, in ablation mode, electrosurgical systems use high-frequency electrical energy to ablate soft tissue, such as sinus tissue, fatty tissue, or tissue within a joint, such as the meniscus, or cartilage or synovial tissue. Some electrosurgical systems include suction, which can remove ablated tissue during treatment, to control the rate of tissue treatment and to help cool the handheld device.

[0004] Mechanical cutting tools for tissue resection have also been used for many years. These types of tools typically include a powered handpiece and a rotating cutting blade fixedly mounted to the distal end of the handpiece. In arthroscopic or endoscopic surgery, both mechanical and electrosurgical tools are frequently exchanged within a single cannula, citing the need to combine both options into a single device. This could reduce surgical time and complications associated with blood loss. However, combination devices generally tend to involve compromises. For example, at least a portion of the electrosurgical assembly is preferably located on the exterior surface of the device, with the interior portion of the device dedicated to wicking and movable mechanical cutting components. Reliably mounting the electrosurgical assembly with minimal changes in the exterior profile is difficult. Previously attempted solutions compromised by providing a probe with a larger profile size or by reducing the functionality of either the mechanical cutting or electrosurgical treatment. Therefore, there is a need to provide a combination device including a reliably mounted electrosurgical assembly structure while keeping the profile size of the instrument to a minimum without compromising both the mechanical cutting and electrosurgical treatment functions.

[0005] As a further example, mechanical cutting tools may include multi-purpose handles that include a motor. These handles and associated components may include metallic, electrically conductive components that are better conductors of heat. Application of electrosurgical energy may heat fluids drawn through the device that may be transported through these handle components. Previously attempted solutions may include adding insulating or poorly conductive components that may be bulky, or alternatively, adding temperature sensing that may interrupt treatment. Therefore, there is a need to provide a combination device that includes a means to limit the temperature of the fluid drawn through the device without compromising both the mechanical cutting and electrosurgical treatment functions. U.S. Patent Application Publication No. 2020 / 222108 describes an arthroscopic tissue resection probe, the probe including an elongated shaft with outer and inner sleeves formed from a conductive material extending about the axis to a working end. U.S. Patent Application Publication No. 2008 / 188848 describes a surgical tool arrangement including an electric handpiece cooperating with a combined electrosurgical-mechanical cutting instrument. U.S. Patent Application Publication No. 2003 / 163126 describes a surgical instrument and method that provides enhanced suction of air bubbles and reduced drag during surgical instrument placement. U.S. Patent Application Publication No. 2015 / 173827 describes an electrosurgical device having a tubular outer shaft and an inner shaft.

[0006] Notation and Terminology Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, companies that design and manufacture electrosurgical systems may refer to components by different names. This document does not intend to distinguish between components that differ in name but not function.

[0007] In the following discussion and claims, the terms "including" and "comprises" are used in an open-ended manner and should therefore be interpreted as meaning "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, that connection may be through a direct connection or through an indirect connection via other devices and connections.

[0008] Reference to a singular item includes the possibility that there are plural of the same items. More specifically, as used in this specification and the appended claims, the singular forms "a," "an," "said," and "the" include the plural unless the context clearly dictates otherwise. It should be further noted that the claims may be drafted to exclude any optional element. Accordingly, this specification serves as a priori basis for the use of such exclusive terms, such as "solely," "only," and the like, in connection with the recitation of claim elements or the use of a "negative" limitation. Finally, unless otherwise defined, all technical and scientific terms used herein should be understood to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0009] "Ablation" shall mean the removal of tissue based on tissue interaction with plasma.

[0010] "Mode of ablation" shall refer to one or more characteristics of ablation. The absence of ablation (i.e., the absence of plasma) shall not be considered an "ablation mode." A mode that performs only coagulation shall not be considered an ablation mode.

[0011] "Active electrode" shall mean an electrode of the disclosed embodiments that produces an electrically induced tissue altering effect when in contact with or in proximity to tissue targeted for treatment.

[0012] "Return electrode" shall mean an electrode of the disclosed embodiments that serves to provide a current path for charge to the active electrode and / or that does not itself produce an electrically induced tissue altering effect on the tissue targeted for treatment.

[0013] Where a range of values ​​is provided, it is understood that every intervening value between the upper and lower limits of that range, and any other stated or intervening value within that stated range, is encompassed within the invention. It is also contemplated that any optional feature of the described inventive variations may be set forth and claimed independently or in combination with any one or more of the features described herein.

[0014] All existing subject matter (e.g., publications, patents, patent applications, and hardware) described herein is incorporated herein by reference in its entirety, except to the extent that the subject matter may conflict with the subject matter of the present invention, in which case the present invention will take precedence. The referenced items are provided solely for their disclosure prior to the filing date of the present application. Nothing herein should be construed as an admission that the present invention is not entitled to antedate such material by virtue of prior invention. [Brief explanation of the drawings]

[0015] For a detailed description of the exemplary embodiments, reference will now be made to the accompanying drawings.

[0016] [Figure 1] 1 illustrates an exemplary system including a combination ablation probe and associated instruments connected thereto, according to the present disclosure. [Figure 2] 1 illustrates a blade portion of a combination ablation probe according to the present disclosure. [Figure 3A] 1 shows a perspective view of a blade distal portion of a combination ablation probe according to the present disclosure. [Figure 3B] 3B illustrates a bottom view of the distal portion of the blade shown in FIG. 3A in accordance with the present disclosure. [Figure 3C] 3B illustrates a side view of the distal portion of the blade shown in FIG. 3A in accordance with the present disclosure. [Figure 3D] 3B illustrates a cross-sectional view of the distal portion of the blade shown in FIG. 3A in accordance with the present disclosure. [Figure 4A] 10 shows a top view of another embodiment of a blade distal portion of a combination ablation probe according to the present disclosure. [Figure 4B] 4B shows a side view of the distal portion of the blade of FIG. 4A in accordance with the present disclosure. [Figure 5A] 10 shows a perspective view of another embodiment of a blade distal portion of a combination ablation probe in accordance with the present disclosure; [Figure 5B] 5B illustrates an exploded view of the distal portion of the blade shown in FIG. 5A in accordance with the present disclosure. [Figure 5C] 5B illustrates another view of the distal portion of the blade shown in FIG. 5A according to the present disclosure. [Figure 5D] 5B illustrates a side view of the distal portion of the blade shown in FIG. 5A in accordance with the present disclosure. [Figure 5E] 5B illustrates an end view of the distal portion of the blade shown in FIG. 5A in accordance with the present disclosure. [Figure 5E] 5B illustrates another exploded view of the blade distal portion shown in FIG. 5A in accordance with the present disclosure. [Figure 5G] 5B illustrates a top view of the distal portion of the blade shown in FIG. 5A in accordance with the present disclosure. [Figure 6] 10 shows an end view of another embodiment of a blade distal portion of a combination ablation probe according to the present disclosure. [Figure 7]10 shows an end view of another embodiment of a blade distal portion of a combination ablation probe according to the present disclosure. [Figure 8A] 10 shows a perspective view of another embodiment of a blade distal end of a combination ablation probe in accordance with the present disclosure; [Figure 8B] 8B illustrates a cross-sectional view of the distal portion of the blade shown in FIG. 8A in accordance with the present disclosure. [Figure 9A] 10 shows a top view of another embodiment of a blade distal end of a combination ablation probe according to the present disclosure. [Figure 9B] 9B illustrates a side view of the distal portion of the blade shown in FIG. 9A in accordance with the present disclosure. [Figure 10A] 10 shows a perspective view of another embodiment of a blade distal end of a combination ablation probe in accordance with the present disclosure; [Figure 10B] 10B illustrates an exploded view of the distal portion of the blade shown in FIG. 10A in accordance with the present disclosure. [Figure 10C] 10B illustrates a top view of the distal portion of the blade shown in FIG. 10A in accordance with the present disclosure. [Figure 10D] 10B illustrates an end view of the blade distal portion shown in FIG. 10A in accordance with the present disclosure. [Figure 10E] 10B shows a cross-sectional view of the distal portion of the blade shown in FIG. 10A in accordance with the present disclosure. Summary of the Invention

[0017] Generally, the present disclosure describes a system that includes a combination device that both mechanically cuts tissue and electrosurgically treats tissue. Accordingly, various embodiments are directed to various systems and methods for removing tissue using mechanical cutting, electrosurgical ablation, and suction. The specification now turns to exemplary systems.

[0018] Various embodiments are directed to a combination arthroscopic probe for removing and treating tissue in a patient, including a handle portion and a blade portion. The handle portion includes a motor selectively coupled to a control box for controlling the motor. The blade portion includes an outer sleeve having a lumen extending therethrough and an inner shaft along the lumen. The outer sleeve can be fixed to the handle portion to be a fixed or stationary sleeve. The outer sleeve has a window at its distal end, the window having a cutting blade. The inner shaft can also have a cutting blade at its distal end and is coupled to a motor operable to move the inner shaft and cooperate with the outer sleeve window cutting blade to mechanically cut tissue. The inner shaft can rotate. The inner shaft can define a window axially aligned with the outer sleeve window. The inner shaft can include an elongated bore in communication with a suction device configured to remove fluids and excise byproducts from the treatment site through the inner shaft window and along the inner shaft.

[0019] The outer sleeve includes an at least partially exposed conductive material defining an exposed conductive portion at the distal end of the outer sleeve. The outer sleeve may support a dielectric spacer that may define a portion of the outer sleeve inner lumen. The dielectric spacer may support the active electrode and electrically insulate the active electrode from the outer sleeve. The dielectric spacer may be formed of any electrically insulating material that is preferably resistant to degradation from the plasma. The dielectric spacer may be formed of a ceramic. The dielectric spacer is configured to electrically insulate the active electrode from the exposed conductive portion of the sleeve such that the sleeve may be electrically coupled to an RF generator and operate as a return electrode.

[0020] One example of a tissue ablation probe is disclosed for mechanical ablation and electrosurgical treatment of tissue. The probe has an electrically conductive tubular distal end with a cutting window on a first circumferential side and an electrically insulating spacer wrapped around a second circumferential side. An active electrode is fixedly attached to the electrically insulating spacer. The active electrode has two angularly offset portions. A first portion extends circumferentially and axially along the tubular distal end. A second portion extends from the distal end of the first portion across the tubular distal end. The second portion has at least one flange that engages a corresponding notch in the electrically insulating spacer to resist separation of the active electrode from the electrically insulating spacer.

[0021] In some specific embodiments, the second portion extends perpendicular to the longitudinal axis. The second portion may define the distal-most surface of the tissue ablation probe. The first portion may be axially tapered to precisely incise tissue at the distal end of the first portion. In some examples, embodiments, at least one flange may extend proximally into the electrically insulating spacer, or the at least one flange may include bilateral flanges. The second portion may define a distally facing concave surface that helps deflect external forces on the active electrode during use. In some exemplary embodiments, the at least one flange may engage with the notch and concomitantly position the active electrode axially to maintain an axial gap between the insulating spacer and the proximal end of the active electrode, the axial gap configured to reduce stress concentrations along the tubular distal end during use. In some exemplary embodiments, the insulating spacer may extend around the tubular distal end to the cutting edge of the cutting window. The insulating spacer may extend over and cover the distally-facing end surface of the tubular distal end, thereby defining at least a portion of the distal-most end of the tissue ablation probe. The active electrode may include a neck extending proximally from a first portion of the active electrode, configured to extend along a tunnel through the insulating spacer and thereby retain the active electrode in a second position proximally separated from the second portion. In some exemplary embodiments, the tissue ablation probe may include a retaining clip extending around the outer surface of the insulating spacer and electrically and mechanically coupled to the tubular distal end. Both the tubular distal end and the retaining clip may define the outer surface of the tissue ablation probe. The retaining clip may include a distally extending tab on the same circumferential side as the active electrode, configured to align the proximal end of the active electrode and the retaining clip according to a target spacing, thereby improving electrosurgical tissue effects. The retaining clip may include opposing radially recessed ends.

[0022] Another exemplary embodiment of a tissue ablation probe for mechanically ablating and electrosurgically treating tissue is disclosed. The probe includes a tubular distal end defining a return electrode. An aperture having a cutting blade is disposed on a first circumferential side of the tubular distal end. An insulator spacer is wrapped around a second circumferential side of the tubular distal end opposite the aperture. An active electrode is secured to the insulating spacer, the active electrode having a first portion extending axially and circumferentially along the tubular distal end and a retention hook extending from and angularly offset from the distal end of the first portion. The retention hook is configured to attach the distal end of the active electrode to the insulating spacer and resist separation of the active electrode from the insulating spacer.

[0023] In some specific embodiments, the retention hook may define a distal-facing surface of the tissue ablation probe. The retention hook may include a first protrusion extending toward a longitudinal axis of the tissue ablation probe and a flange protrusion extending from the first protrusion configured to fit within a notch in the distal end of the insulating spacer. The flange protrusion may extend along the longitudinal axis.

[0024] Also disclosed herein is a tubular end effector for a combination electrosurgical and mechanical ablation assembly. The end effector includes a metal component defining a cutting window on a first circumferential side of the tubular end effector. The metal component defines a return electrode of the assembly. The end effector also includes a ceramic spacer attached to the metal component such that the ceramic spacer forms a second circumferential side of the tubular end effector opposite the first circumferential side. The distal end surface of the ceramic spacer includes a groove. The tubular end effector also includes an active electrode fixedly mounted to the ceramic spacer, the active electrode being positioned opposite the cutting window. The active electrode includes a circumferential treatment surface and a retention hook extending from and angularly offset from the distal end of the circumferential treatment surface. The retention hook includes at least one protrusion for operably coupling within the groove, thereby retaining the active electrode with the tubular end effector.

[0025] Another exemplary embodiment of an arthroscopic tissue resection probe is disclosed herein, which may include an elongated shaft having an outer conductive sleeve and an inner sleeve. Each sleeve includes a distal region defining a cutting window, and the inner sleeve is rotatable to cut tissue. The probe may also include a ceramic body disposed on an outer surface of the outer sleeve along the distal region of the outer sleeve. An electrode is supported by the ceramic body, and a first suction opening extends through the electrode, ceramic body, and outer sleeve for aspirating fluids and ablation byproducts therethrough and into the interior of the shaft. A second suction opening is defined at least in part by the conductive sleeve and is spaced from the electrode for aspirating fluids and ablation byproducts therethrough and into the interior of the shaft.

[0026] In some exemplary embodiments of the arthroscopic tissue resection probe, the electrode, ceramic body, and outer sleeve all include a 360-degree bounded hole spaced from the outer sleeve cutting window that defines a first suction opening. The bounded hole is aligned for suction through the bounded hole into the interior of the shaft, and the bounded hole is aligned along an axis transverse to the longitudinal axis of the elongate shaft. In some exemplary embodiments of the probe, both the conductive sleeve and the inner sleeve define a 360-degree bounded hole that is spaced from the electrode and forms a second suction opening when aligned. Alternatively, the second suction opening can be defined by a boundary defined by the cutting edges of both sleeves. The second suction opening can be disposed proximally relative to the electrode. The second suction opening can be disposed proximally relative to the first suction opening. The second suction opening can be disposed proximally relative to both cutting windows. The first and second suction openings can each have an opening size configured to balance suction through the first suction opening with a flow rate that forms a stable plasma at the electrode. The second suction opening can be configured to receive fluid therethrough and cool the fluid drawn through the first suction opening, thereby reducing heating of the probe.

[0027] In a further exemplary embodiment disclosed herein, an arthroscopic tissue resection probe may include an elongate shaft having an outer conductive sleeve and an inner sleeve, each sleeve having a distal region defining a cutting window, the inner sleeve being rotatable for cutting tissue. A ceramic body is disposed along an outer surface of the outer sleeve on the distal region of the outer sleeve. An electrode is supported by the ceramic body, and a first suction opening extends through the electrode, ceramic body, and outer sleeve for aspirating fluids and ablation by-products therethrough and into the interior of the shaft. The probe also includes a clip or collar covering a portion of the ceramic body and secured to the distal region, the clip or collar being separately formed and secured directly to the conductive sleeve.

[0028] In some exemplary embodiments, the collar or clip circumferentially sandwiches the ceramic body between the conductive sleeve and the collar or clip. The collar or clip may be spaced proximally from the cutting window. The collar or clip may define a thin band that wraps completely around the entire conductive sleeve. The collar or clip may be conductive and in electrical communication with the conductive sleeve. DETAILED DESCRIPTION OF THE INVENTION

[0029] The following discussion is directed to various embodiments. While one or more of these embodiments may be preferred, the disclosed embodiments should not be construed 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 broad applicability, and that the discussion of any embodiment is intended only as 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.

[0030] The present disclosure generally includes a system that combines mechanical resection and electrosurgical tissue treatment into a single device, including, but not limited to, tissue ablation, cutting, shrinkage, and coagulation. Combining these two modalities may reduce the need for multiple instruments during procedures such as endoscopic or arthroscopic surgery. The mechanical blade edge surfaces of both the stationary and rotating members preferably comprise metal. Both the active and return electrodes are preferably disposed on the blade's stationary outer sleeve. The stationary sleeve may provide electrical communication between the RF energy source and the electrodes. The active electrode may also extend to and around the most distal surface of the device, improving accessibility of the active electrode to the target tissue and thereby improving electrosurgical treatment of the target tissue. The electrode may also be integral with or form a portion of the outer sleeve portion and be configured to maintain a low-profile device distal end with minimal change in outer diameter due to the addition of an electrosurgical assembly.

[0031] An exemplary surgical system 100 is shown generally in FIG. 1 and includes a combination arthroscopic resection device 110 having a handle portion including a motor drive unit (“MDU”) 112. The handle portion may be removably coupled to a blade 114. The MDU 112 may be operably coupled to a controller / power supply 120 via a cord 130. Actuation of the MDU 112 moves one portion of the blade 114 relative to another portion of the blade to resect tissue. The combination device 110 may be configured to mechanically resect tissue in a manner similar to commercially available metal shavers or burrs having a high-speed rotating inner shaft disposed within a stationary outer sleeve and coupled to an MDU. The system 100 also includes an RF generator 140 for providing RF power to the blade 114 via an RF power cord 116. In some embodiments, the controller / power supply 120 and the RF generator 140 may be in a single housing. In some embodiments, the controller / power supply 120 and the RF generator 140 may be in communication with each other. In some embodiments, one of the controller / power supply 120 and the RF generator 140 may be in communication with the flow control device 220 (121, 141).

[0032] The combination arthroscopic resection device 110 includes a suction tube 210 that may extend along the MDU 112 and may be coupled to a suction control 220. The suction control 220 may control fluid flow or negative pressure through the tube 210 and may include a suction pump or multiple suction pumps (not shown). The suction control 220 may be a peristaltic pump having a rotor for providing and controlling suction of tissue and fluid from the target site and along the device 110. In some embodiments, the suction may be fluidly coupled to a wall suction that draws a vacuum at a consistent level. The suction control 220 may include a pinch valve with multiple positions that pinch or release the suction tube, or an alternative means for varying the fluid conduit size (orifice) associated with the suction tube. In some embodiments, the suction may be controlled at least in part by a control valve disposed on the MDU 112 that may selectively control a value related to suction through the device. The blade 114 includes at least one lumen extending through the blade 114 and communicating with the suction tube 210 at the blade distal portion 230 so that fluids and debris can be aspirated through a window in the blade distal portion 230 and flow along the lumen and through the tube 210.

[0033] The controller / power supply 120 may be, for example, the Dyonics® Power Shaver system or the Dyonics® EP-18 Shaver system supplied by Smith & Nephew, Inc. of Andover, Mass. The generator 140 may be, for example, a commercially available generator such as the COBLATION WEREWOLF system supplied by Smith and Nephew, Inc. of Andover, Mass. The blades 114 are sized to suit the desired application. For example, blades for use in the shoulder may be sized differently than blades for use in the prostate. Applications include, for example, use in the shoulder, knee, and other joints, as well as in natural orifices such as the uterus, urethra, nasal cavity, and oral cavity. The MDU 112 includes a drive shaft (not shown) configured to selectively couple with the proximal end of the blade 114 and may include coupling means similar to those disclosed in commonly assigned U.S. Pat. No. 7,150,747, the entire disclosure of which is incorporated herein by reference.

[0034] 2, an exemplary blade 114 is shown including an RF power cord 116 terminating at a free end with a connector 320. The connector 320 may have at least two prongs 322 and 324 designed to connect to either the generator 140 or a footswitch. Each prong connects to one of two separate conductors in the RF power cord 116, providing both a supply path and a return path for the blade 114. Additional prongs (not shown) may provide further information to the RF generator / controller 140, such as the type of device and / or desired or candidate settings, such as fluid flow settings or power settings. Alternatively, the connector may include a series of pins configured to connect to a connector on the RF generator 140, such as the system described in commonly assigned U.S. Pat. No. 9,333,024, the entire disclosure of which is incorporated herein by reference.

[0035] The blade 114 may mechanically resect tissue in a manner similar to other commercially available mechanical resection devices. For example, the blade 114 may include at least two elongated sleeves or tubes arranged concentrically, one inside the other. One of the elongated tubes may be fixedly attached to the MDU 112 and may define an outer sleeve, which is a stationary sleeve during use. Another of the sleeves is defined as an inner sleeve concentric with the outer sleeve coupled to the MDU 112 so as to be rotatable at high speed relative to the stationary outer sleeve. The blade 114 may be attached to the MDU 112 using various hub-type structures, such as threaded and press-fit connections. Various embodiments of the MDU 112 include motor drive units manufactured by Smith & Nephew, Inc. of Andover, Mass., such as part numbers 7205354, 7205355, and 7205971. Various cutting surfaces may provide the mechanical cut. Such surfaces include, for example, curved, burred, straight, wavy, or small blades. Mechanical cutting is typically accomplished at speeds of thousands of cycles per minute (e.g., rotational or reciprocating).

[0036] 3A-3D, an exemplary embodiment of the distal end 300 of the blade 114 is shown. The blade distal end 300 includes both a means for mechanically and electrosurgically treating tissue. The blade distal end 300 is generally tubular and includes an outer sleeve 310 having a window 320 on a first circumferential side of the sleeve 310. The window 320 has an edge surface 325 at the outer periphery of the window 320. At least a portion of the edge surface 325 is sufficiently sharp to cut tissue when used in combination with an inner sleeve 350. The inner sleeve 350 may extend along the lumen or bore of the outer sleeve 310 and may have a similar window 355 and an edge surface 356 configured to cooperate with the edge surface 325 to mechanically cut tissue as the inner sleeve rotates.

[0037] The outer sleeve 310 is preferably a metallic or conductive tube configured to provide an electrical pathway from the electrical cord 116 along the sleeve 310. The outer sleeve 310 may be at least partially coated or covered by a layer or sheath 305 to electrically insulate a portion of the outer sleeve 310 and limit the exposed portion of the outer sleeve to a controlled area. For example, a proximal portion of the outer sleeve 310 adjacent the MDU 112 may be sufficiently exposed to electrically couple to the cord 116 and thereby to the RF generator 140 (not shown). A distal portion of the outer sleeve 310 may also be exposed, exposing a metal edge surface 325 for mechanical cutting. The exposed surface area of ​​the outer sleeve 310 (not coated or covered with insulating material) defines a return electrode 360 ​​of the electrosurgical assembly.

[0038] Outer sleeve 310 supports insulating spacer 380 and active electrode 370. Active electrode 370 has a rounded outer surface and nests at least partially within spacer recess 386, minimizing any additional size increase so that the device can fit within a 5 mm cannula. Active electrode 370 is electrically coupled to RF generator 140 via a cable or wire that extends along blade 114 (not shown) and connector 320. Active electrode 370 and associated cable are preferably electrically insulated from outer sleeve 310, allowing outer sleeve 310 to act as return electrode 360. Active electrode 370 is electrically insulated from outer sleeve 310 / return electrode 360 ​​by electrically insulating spacer 380. Because active electrode 370 is intended to selectively ablate tissue, thus forming a plasma thereon, spacer 380 is preferably an electrically insulating material that is also resistant to plasma-induced degradation or plasma-resistant. The material may include ceramic or glass materials such as alumina, zirconia, etc.

[0039] The active electrode 370 should preferably be made of a material that is resistant to plasma degradation, such as tungsten, titanium, platinum, molybdenum, aluminum, gold, and copper. More specifically, the active electrode 370 can be made of a different material than the inner and outer sleeve materials. While stainless steel is preferred for mechanical cutting edges, stainless steel tends to be less resistant to plasma degradation and is therefore not a preferred material for the ablation electrode 370. However, tungsten is a more brittle metal than stainless steel and is therefore not preferred for the cutting edge because it may form particles during mechanical ablation. Furthermore, the inventors have found that the distance between the edge or periphery of the active electrode 370 and the cutting edge 325 should be greater than a predetermined distance. This predetermined distance is configured to prevent unintentional plasma formation on the cutting edge 325. If the distance is shorter than this predetermined distance, plasma may form along the cutting edge 325, causing unintentional tissue treatment on tissue other than the target tissue, and the plasma may dull or deteriorate the cutting edge 325, potentially resulting in frustrating mechanical ablation. The minimum distance between the periphery of the active electrode 370 and the cutting edge 325 should be at least 2 mm measured along the outer surface of the device.

[0040] To minimize any additional diameter to the distal end 300 due to the electrosurgical assembly, the spacer 380 is a thin component that circumferentially engages the outer surface of the sleeve 310. The inner surface of the spacer 380 is contoured to mate with the outer surface of the sleeve 310 and may be attached using, for example, an adhesive. The spacer 370 is preferably formed from a high-strength ceramic that provides structural integrity to the outer sleeve 310 and may add rigidity to the outer sleeve. The spacer 380 may be secured using an adhesive; therefore, a larger mating surface area for adhesion is preferred for a higher level of hold between the two components. As shown throughout Figures 3A-3D, the spacer 380 may extend proximally along the outer sleeve 310, at least as far as the sheath 305. This proximal extension may improve the fixation of the spacer 380, while also insulating the proximal side of the return electrode 360. This may make the proximal side of the active electrode more inert and less susceptible to plasma formation. Accordingly, the distal end 300 may include a clip or collar 390 annularly disposed around the spacer 380. The clip 390 may be electrically conductive and in electrical communication with the outer sleeve 310, thus forming a portion of the return electrode 360. The clip 390 may be welded 392 to the outer sleeve 310, thus restoring target proximity of the return electrode 360 ​​proximally adjacent the active electrode 370. The clip 390 may also increase fixation between the sleeve 310 and the spacer 380. The spacer 370 may include an annular notch configured to receive the clip 390 therein while minimally increasing the outer diameter of the distal end 300.

[0041] As best shown in FIG. 3D , the inner sleeve 350 may define an elongated fluid suction conduit 312 along it in fluid communication with the suction tube 210, thereby allowing tissue debris formed during mechanical resection to be removed through the windows 320, 355 and along the conduit 312. A second entrance 371 into the conduit 312 is formed by at least one spacer aperture (best seen in FIG. 3D ) aligned with the active electrode aperture 372. The electrode 370, ceramic spacer 380, and outer sleeve 310 each define an aspiration aperture that may define a 360-degree bounded aperture. The second entrance 371 defined by these apertures may be spaced from the outer sleeve cutting window 320, with the bore aligned for aspiration through the interior of the shaft and thus the conduit 312. The multiple apertures may be aligned along an axis transverse to the longitudinal axis of the elongated shaft. During electrosurgical treatment, the inner sleeve 350 may be stationary and aligned to at least partially face this second inlet 371. An example of this is disclosed in more detail in commonly owned International Patent Application No. PCT2020 / 019479, filed February 24, 2020, entitled "COMBINATION ELECTROSURGICAL AND MECHANICAL RESECTION DEVICE," which is incorporated herein by reference. The second inlet is configured to draw fluid across the active electrode 370 during use and remove fluid, debris, and plasma by-products through the active electrode surface. Controlling the value associated with the suction flow rate may also adjust the electrosurgical tissue effect, as disclosed in commonly owned International Patent Application No. PCT2020 / 019479, filed February 24, 2020, entitled "COMBINATION ELECTROSURGICAL AND MECHANICAL RESECTION DEVICE," which is incorporated herein by reference.

[0042] The distal end 300 may include means for regulating the temperature of the device, particularly its exterior surfaces, such as the exterior surface of the MDU 112. When fluid is drawn through the second inlet, while supplying electrosurgical energy to the active electrode 370, the fluid temperature may increase. This increased temperature may increase the temperature along the device's surfaces, including the device's handle and fluid lines. The surface area of ​​each of these components must remain below the contact temperature specified in the IEC 60601-1 standard. Because the MDU 112 is typically reusable, it may be formed of a metallic material, such as aluminum, which typically has a higher thermal conductivity than disposable electrosurgical devices primarily formed of polymers. One embodiment may include a temperature sensor along the blade 114 that may communicate with the RF generator upon detection of a predetermined temperature increase, which may trigger a warning to the user or alter the RF energy output. The temperature sensor may be at least similar to those disclosed in commonly owned US Pat. Nos. 8,355,799, 8,696,659, 9,452,008, or 10,420,601, which are incorporated herein by reference.

[0043] In some embodiments, to mitigate temperature rise, cooler fluid may be pumped through the device. This may regulate the temperature of the fluid aspirated through the device lumen 312 and then through the MDU 112. The distal end 300 may include a bypass aspiration pathway 363 completely spaced from the active electrode 370 to pump cooler fluid into and along the lumen 312. The pathway 363 may extend through openings in both the outer and inner sleeves (310, 350), providing a route to draw a portion of the fluid from within the joint cavity into the fluid aspiration conduit 312. This portion of the fluid may be relatively cooler than the fluid aspirated through the inlet 371 and thereby through the active electrode aperture 372. To some extent, depending at least on the power setting of the RF generator 140 and the rate of fluid aspiration, the aspirated fluid and by-products through the second inlet 371 may have an elevated temperature as a result of passing through the active electrode 370. Over time, this elevated temperature can increase the exterior surface temperature of the MDU 112 and tubing 210. The secondary pathway 363 can multiply these elevated temperatures with cooler fluid to cool the fluid, thereby mitigating the elevated exterior surface temperature. As shown in FIGS. 3B, 3C, and 3D, the bypass pathway 363 can be spaced proximally from the active electrode 370. The bypass pathway 363 can be disposed on the opposite circumferential side from the active electrode 360. By being spaced away from the active electrode 370, the bypass pathway 363 preferably draws into the fluid aspiration conduit 312 a fluid whose temperature is less affected by the active electrode energy. The bypass inlet 363 is defined by overlapping holes in the inner sleeve 350 and holes through the outer sleeve 310. Each hole can define a 360-degree bounded hole or aperture.

[0044] Returning to FIG. 3A , another optional bypass inlet 353 (in addition to or instead of bypass inlet 363) is shown, defined by the relative location between the two windows (320, 355). This path 353 is adjustable, so that the inner sleeve 350 can be rotated to a position that adjusts the aperture entrance size if the temperature of the MDU increases. For example, a temperature sensor located along the device 110 can sense a value indicative of an increased temperature, and the temperature sensor communicates with the MDU 112. The MDU 112 can then rotate the inner sleeve 350 to a position that forms the bypass inlet 353. When the temperature sensor senses a value indicative of the temperature decreasing to a predetermined value, communication between the sensor and the MDU 112 can be configured to return the inner sleeve 350 to a fully closed configuration. When the temperature sensor senses a value indicative of the temperature increasing or remaining at an increased value, communication between the sensor and the MDU 112 can be configured to increase the entrance size by moving the inner sleeve 350 to a different position. In an alternative embodiment not shown, the bypass pathway may include multiple pathways spaced apart from the active electrode 360. Alternatively, the bypass pathway may include at least one aperture passing only through the inner sleeve 350 (not shown) on the opposite axial side of the inner sleeve window 355 and thus the active electrode 370.

[0045] The flow associated with the bypass inlets 363, 371 may also regulate the tissue effect and energy within any plasma formed at the active electrode 370. The combined device may be fluidly coupled to a wall suction, which may have a high suction flow rate, where the flow may be too strong to stably form a plasma at the active electrode 370. A flow that is too fast may extinguish or destabilize any plasma that forms at the active electrode 370. Thus, the bypass inlets 363, 371 may balance or regulate the fluid flow rate through the electrode aperture 372, thereby maintaining a more stable plasma at the active electrode 370. For example, the RF generator may sense values ​​indicative of plasma stability, as disclosed in at least commonly owned U.S. Patent Nos. 8,192,424 and 10,448,988, which are incorporated herein by reference. When the RF generator senses a value related to non-target plasma stability, it can communicate with the MDU 112 so that the inner sleeve 350 can be moved to a position that forms the bypass inlet 371 and adjusts the flow of fluid through the aperture 372, thereby stabilizing the plasma.

[0046] 4A and 4B, views of another embodiment of the distal tip 400 are shown with the inner sleeve removed for clarity. Similar elements are given the same numerical designations as the distal tip 300. The distal tip 400 may include an outer sleeve 310 supporting an insulating spacer 480, which supports the active electrode 470. To maintain a minimal outer diameter of the device distal tip 400, the thin spacer 480 wraps circumferentially around a portion of the outer sleeve's outer surface. The spacer 480 is configured to electrically insulate the active electrode 470 from the outer sleeve 310, which is electrically connected as a return electrode as disclosed herein. The spacer 470 wraps a limited distance around the outer sleeve's outer surface to define an outermost boundary along and around the outer sleeve 310, which exposes a sufficient surface portion of the outer sleeve 310 around the active electrode 470, the exposed surface portion defining the surface area of ​​the return electrode 360. To maintain a minimal cross-sectional profile, the spacer 480 is a thin component. The spacer 480 may be approximately 0.010 inches thick. The inner surface of the spacer 480 mates with the outer surface of the sleeve 310 and may be adhesively bonded to the outer sleeve 310. As disclosed hereinabove, a larger contact area for mating the two is preferable if a strong bond is to be formed between the sleeve 310 and the spacer 480. Therefore, the spacer 480 preferably extends substantially from the active electrode 470 circumferentially around the sleeve 310 and proximally along the sleeve 310. Stated another way, the spacer 470 may extend further around and along the sleeve 310 than the minimum required for electrical isolation between the sleeve 310 and the active electrode 470, increasing the fixation between the sleeve and the spacer 480.

[0047] However, this bias toward fixity can impair electrosurgical tissue effects. The overall surface area of ​​the return electrode 360 ​​is reduced. If the overall surface area of ​​the return electrode 360 ​​begins to approximate the overall surface area of ​​the active electrode 470, tissue effects, which may include plasma, may unintentionally launch on the return electrode 360. The distance between the active and return electrodes may also be uneven around the circumference of the active electrode 470. If the active electrode 470 is spaced more unevenly from the return electrode 360 ​​at one end than the other, tissue effects may treat tissue only along some sides of the active electrode 470. The closer the active and return electrodes are, the higher the current density. A high current density makes it easier to form plasma on the active electrode. However, if the spacing between the active and return electrodes is greater between some peripheral portions of the active electrode 470 than others, the current density is poor in those areas, and plasma is less likely to form around the corresponding portions. In some cases, plasma may form only along a portion, which may damage the electrode or create a tissue effect that is too aggressive. If the overall distance between the circumferences of the return and active electrodes is too great, plasma firing may be inconsistent or require a higher voltage input to achieve. Therefore, a balance between the spacer 480 for stronger bonding with the sleeve 310 and ensuring a uniform electrosurgical tissue effect is preferred.

[0048] Similar to the clip 390, the distal tip 400 includes a collar 490 that wraps around the outer surface of the spacer 480 at its proximal end. The collar 490 may extend 360 degrees around the transverse plane of the distal tip 400. This not only provides additional fixation of the proximal portion of the spacer 380 but may also act as the return electrode 360. The collar 490 adds fixation between the sleeve 310 and the spacer 480 and avoids interference with the inner rotating sleeve 350. The collar 490 may improve the attachment of the spacer 480 to the outer sleeve so that it can withstand clinically relevant loads during a procedure without compromising the integrity of any component of the device. The collar 490 extends around the distal tip 400 and may be welded 480 to the outer sleeve 310 to secure it in place and form consistent electrical communication with the outer sleeve 310. The collar 490 provides mechanical retention for the spacer 480. Thus, the spacer 480 is circumferentially sandwiched between the outer sleeve 310 and the collar 490. The spacer 480 may include an outer annular recess configured to nest at least a portion of the collar 490. The collar 490 may be spaced proximally from the window 320 and the active electrode 470. The collar 490 may be 0.0020 to 0.0040 inches thick.

[0049] With respect to electrosurgical tissue effects, the collar 490, like the clip 390, may be electrically conductive and in electrical communication with the outer sleeve 310, thereby contributing to the effective surface area of ​​the return electrode 360. The collar 490 may effectively move the outer circumference of the return electrode 360 ​​closer to the proximal end of the active electrode 470, thereby creating a resulting return electrode outer circumference that more uniformly surrounds the active electrode 470. Stated another way, the spacing between the active electrode 470 and the return electrode 360 ​​becomes more uniform around more sides of the active electrode 470 due to the added collar 490. The collar 490 is tightly wrapped around the spacer 480 and the outer sleeve 310 and may include a weld 480 to securely secure the collar 490 to the outer sleeve 310. Example locations for the weld 480 are shown. Another example may include a circumferential laser weld around the mating portions of the sleeve 310 and collar 490. Electrical communication between the outer sleeve portion of the return electrode 360 ​​and the collar 490 may be through the weld 480 and the surface contact.

[0050] 5A-5G show another distal tip embodiment 500 similar to the embodiments disclosed above. Similar elements are given the same numerical designations as distal tips 300 and 400. Distal tip 500 includes an outer sleeve 510 within which an inner sleeve 350 is coaxially disposed. The inner sleeve 350 can rotate relative to the outer sleeve 510 to mechanically ablate tissue through a laterally disposed window. The outer sleeve 510 is at least partially covered by an insulating spacer 580, which supports an active electrode 570. The return electrode 360 ​​can include multiple components or bodies having exposed conductive surfaces and in electrical communication with one another. These components can include the exposed conductive surface of the inner sleeve 350, the exposed conductive surface of the outer sleeve 510, and the externally exposed conductive surface of a retaining clip 590.

[0051] An exploded view of the components of the distal tip 500 is shown in FIG. 5B, with the inner sleeve 350 removed for ease of illustration. The outer sleeve 510 defines an elongated sleeve having a cutting window 520 on a first circumferential side of the distal tip 500. The outer sleeve 510 extends proximally and may be fixedly coupled to a hub configured to operably couple with a handle end that may include the MDU 112. The outer sleeve 510 includes a suction aperture 512 through the outer sleeve wall thickness on a second circumferential side opposite the window 520. The aperture 512 may communicate with a corresponding aperture through the active electrode 570 to aspirate fluids and debris while treating tissue. The distal end of the outer sleeve 510 may define a reduced outer diameter portion 514 formed by reducing the thickness of the sleeve wall. Portion 514 defines a circumferential surface that engages the inner surface of insulating spacer 580, with the reduced outer diameter portion acting as a recess and reduced in diameter to maintain a smaller overall profile of distal end 500. Outer sleeve 510 extends around tip 516 that curves toward the longitudinal axis of sleeve 510, the curve extending to and including angled cutting edge 525 of window 520.

[0052] The spacer 580 is sized to mate with at least the reduced diameter portion 514 of the outer sleeve 510 and covers the circumferential side of the sleeve 510 opposite the window 520. The spacer 580 extends over and fixedly couples to the distal tip 516 of the sleeve. The spacer 580 may define a unibody and have an inner surface contoured to align with and directly engage the outer surface of the sleeve 510 for mating surface-to-surface contact between the two. The inner surface of the spacer 580 may be adhesively bonded to the outer sleeve 510. Extending the spacer around the tip 516 spaces the active electrode 570 from the sleeve 510, and thus the return electrode 360, to reduce unintentional plasma formation on the sleeve 510. In this manner, the spacer 580 defines a distal-facing surface at the most distal end of the distal tip 500. Securement between the spacer 580 around the distal tip 516 and the sleeve 510 may be particularly relevant during use because the very distal tip may be used to elevate and dissect tissue, placing a lifting load on the active electrode 570 and the spacer 580. By wrapping the spacer 580 around the distal tip 516, securement of the spacer 580 to the sleeve 510 is improved. The spacer 580 may extend around the sleeve 510 up to the angled cutting edge boundary 525 of the sleeve window 520. The spacer 580 may surround at least half of the upper circumference of the sleeve 510. Stated differently, as best shown in FIGS. 5C and 5D , the spacer 580 may cover at least half the circumference of the sleeve 510 at the distal end 500. Wrapping the spacer 580 around the sleeve 510 not only increases the surface area available for bonding between the sleeve 510 and the spacer 580, but also creates more equal spacing between the proximal and distal edges of the active electrode 570 and the return electrode 360. The spacings G1 and G2 are substantially equal to one another, as shown in FIG. 5D . Additionally, the inventors have found that during use, the primary force on the distal end of the device is a force directed proximally (F) from the most distal end, which acts to lift the spacer 580 and / or active electrode 570, thereby separating the active electrode 570 and / or spacer 580 from the sleeve 510.Spacer 580 preferably extends over and is joined to the distally facing surface of sleeve 510 .

[0053] The spacer 580 includes multiple recesses for nesting and securing the active electrode 570 and clip 590. The retaining clip 590 surrounds the spacer 580 and may be located within a notch or recess 582 formed on the outer surface of the spacer 580. The clip 590 may be a stainless steel stamped and formed clip that fits around the spacer 580. The recess 582 may mirror the profile of the clip 590 and help create a smoother, more continuous outer surface of the distal end 500, thereby eliminating or reducing snag points therealong. The clip 590 may be welded to the outer sleeve 510 to retain and electrically couple the clip 580. As described herein, the clip 590 provides supplemental fixation between the spacer 580 and the sleeve 510. The clip 590 may define a body portion 591 and free ends 592a, 592b. The free ends 592 a, 592 b may be molded inward relative to the body portion 591 and may be recessed radially inward. This recession preferably follows the contour of the spacer 580 and the transition from the spacer 580 to the sleeve 510. The free ends 592 a, 592 b are preferably fixedly coupled to the outer sleeve 510. The body 591 may define a distally extending tab 593 configured to create more uniform spacing between the active electrode 570 and the return electrode 360. The tab 593 may extend distally toward the active electrode 570 on the same circumferential side of the sleeve 510 as the active electrode 570. The tab 593 may define a circumferential width equivalent to the circumferential width of the corresponding active electrode. Without the tab 593, the spacing between the active electrode 570 and the nearest portion of the return electrode 360 ​​would be biased toward the distal end of the active electrode 570 and may be significantly non-uniform around the active electrode 570. This, as previously explained, may strongly bias plasma formation and tissue effect toward the distal tip of the active electrode 570 and prevent a uniform and controlled electrosurgical tissue effect. The tab 593 may have a lateral or circumferential extent and define a distal-most edge that surrounds or is close to the proximal edge of the active electrode 570.The addition of clip 590 also increases the overall exposed surface area of ​​return electrode 360 ​​that can come into contact with conductive fluid, mitigating any unintentional tissue effects at return electrode 360. For example, clip 590 can increase the effective return electrode 360 ​​surface area by up to 50%, defining the active electrode 570, bringing the surface area ratio back to 1:7.

[0054] The spacer 580 includes a fluid suction aperture 586 that is in fluid communication with and overlaps the corresponding aperture 512 through the sleeve 510 and the active electrode aperture 572. All three apertures communicate to remove tissue debris and fluid from the target site, for example, along with the device, which may be coupled to a vacuum source. The spacer aperture 586 may define a protruding aperture (best seen in FIG. 5F). The protrusion may extend through the sleeve aperture 512 to increase the insulating spacing between the active and return electrodes and may prevent plasma from being emitted through the apertures (512, 572, 586) into the inner or outer sleeve.

[0055] The spacer 580 also nests and holds the active electrode 570 in at least two distinct locations. The two locations may be axially separated by a spacer circumferential surface 588. The first holding location includes an axial tunnel 587 that receives and covers the active electrode leg 577. The axial tunnel 587 may slidingly mate with the leg 577, thereby holding the proximal end of the active electrode 570. An adhesive may be inserted within and along the tunnel 587 to improve retention and limit fluid intrusion along it. The proximal-most ends of the legs 577 may be electrically coupled to wiring extending along the device (not shown).

[0056] Extending distally from tunnel 587 is a circumferential surface 588 configured to support circumferential portion 571 of active electrode 570. Active electrode 570 is a unitary body having circumferential portion 571 and second electrode portion 578. Circumferential portion 571 may define a first treatment surface 571a of active electrode 860 disposed on the circumferential side of distal end 500 opposite window 520. First treatment surface 571a may conform to the outer contour of distal end 500. First treatment surface 571a may taper toward a narrower distal end for more precise dissection. A proximal edge 573 of treatment surface 571a is preferably axially spaced from a corresponding distal edge 584 of spacer 580. This axial space provides relief as active electrode 580 flexes during use. Without this space, proximal edge 583 can place damaging stresses on spacer edge 584 .

[0057] The spacer 580 also retains the active electrode 570 at a distal location axially separated from the proximal retention location (legs 577). The distal end of the active electrode includes a second electrode portion 578 angularly offset from the first portion 571 and from the longitudinal axis of the distal tip 500. The second electrode portion 578 may define a distally-facing treatment surface 579 extending across the distal-most end of the distal tip 500. The second electrode portion 578 has a radial extent. The surface 579 may further include a sloped portion 579a configured to deflect forces (F) during treatment that may separate or peel the active electrode 570 from the spacer 580. The slope 579a defines a distally-facing concave surface. The slope 579a may taper proximally as it extends toward the longitudinal axis. The treatment surface 579 generally enhances the performance of the tip of the active electrode 570. The treatment surface 579 extends to the functional base of the distal tip of the active electrode 570.

[0058] The second electrode portion 578 may extend from the distal end of the first treatment portion 571 and define a hook shape. The second electrode portion 578 may engage a mating surface of the spacer recess 581. The spacer recess 581 may extend from the distal-most surface of the spacer 580. The second electrode portion 578 may have an extension having at least one lateral flange 595 or ridge disposed at an end of the extension. FIG. 5E shows a pair of opposing lateral flanges 595a, 595b defining a triangle. A matching recess 581 in the spacer 580 may receive and retain the opposing lateral flanges 595a, 595b. The second electrode portion 578 defines a second, separate retaining portion. The notch or recess 581 may define opposing grooves that receive the opposing lateral flanges 595a, 595b. As explained above, when the electrode 570 is loaded at the distal tip (F), it may have a tendency to rotate about the electrode neck 577. If significant rotation is allowed, permanent offset of the electrode 570 or fatigue failure of the neck may occur. This second retention location at the distal-most end of the electrode 570 helps to mitigate this failure mode.

[0059] The flanges and alignment grooves are configured to engage with one another and secure the electrode distal end with the spacer. Figures 6 and 7 illustrate other exemplary embodiments having alternative flange and groove configurations. Figure 6 illustrates a distal view of a distal tip 600 in which an active electrode 670 includes a second electrode portion 670 defining the distal-most end of the distal tip 600. The second electrode portion 670 includes opposing "T"-shaped flanges 695a, 695b. The spacer 680 includes alignment grooves 685a, 685b configured to engage with the opposing flanges 695a, 695b and secure the distal end of the electrode 670 with the spacer 680. Figure 7 illustrates a distal view of a distal tip 700 of an exemplary embodiment in which an active electrode 770 includes a second electrode portion 775 at the distal-most end of the distal tip 700. The second electrode portion 775 includes opposing curved flanges 795a, 795b.

[0060] A further embodiment is shown in Figures 8A and 8B, which for ease of understanding only, depict a distal tip 800 having an active electrode 870 and a spacer 860. The active electrode 870 includes bilateral rails 875a, 875b that operably engage bilateral slots along the spacer 860 along the lateral edges of the active electrode 870. This embodiment offers a longer engagement length, but may require an increased cross-sectional area of ​​the distal tip 800, creating a larger profile end compared to the distal tip 500 having a distal retention hooked end.

[0061] Another exemplary embodiment of the distal end 900 is shown in FIGS. 9A and 9B . Similar components are given the same numerical labels. In this embodiment, the collar 990 may function at least similarly to the clip 390, 590, or collar 490 and may surround the spacer 980. The collar 990 may include two axially extending tabs 995 a, 995 b. Each tab 995 a, 995 b may extend along a side lateral to the active electrode 570 to encircle a larger circumference of the active electrode 570. The spacer 980 may include a corresponding notch or recess (not shown) for receiving the collar 990 therein. This recess may match the shape of the collar 990 and help form a smoother, more continuous outer surface, thereby eliminating or reducing snag points along it. The collar 990 may be similar in material and construction to the clip 390 or 590 or collar 490. A collar 990 may be welded to the outer sleeve 910 to retain the collar 990 and electrically couple it to the outer sleeve 910. The spacer 980 may be adhesively bonded to the outer sleeve 510, with the collar 990 providing complementary fixation between the spacer 980 and the sleeve 910. Two distally extending tabs 995a, 995b are configured to improve spacing between the active electrode 570 and the return electrode. As described herein, this may improve electrosurgical tissue effects, as previously described. The addition of the collar 990 also increases the overall surface area of ​​the return electrode much more than the clip 590. For example, the collar 990 may increase the surface area by up to 100%, again keeping the active electrode 570 close to a surface area ratio of 1:10.

[0062] 10A-10E illustrate the distal end 1000 of another exemplary embodiment of a combination tissue ablation probe configured to function similarly to the embodiments disclosed above and, therefore, include similar components. FIG. 10A illustrates the spacer and active electrode for ease of understanding only. The distal end 1000 includes an active electrode 1050 coupled to a spacer 1060, similar to the electrode 570 and spacer 580. The active electrode 1050 includes a first treatment portion 1052 that defines the outer circumferential surface of the distal end 1000. The first treatment surface may taper as it extends distally to a distal tip with a more precise tip for more precise tissue dissection. The first treatment portion 1052 of the active electrode may include a suction aperture 1055 therethrough that is in fluid communication with a suction conduit extending along the probe shaft, similar to the previously described embodiments. The active electrode 1050 also includes a distal hook 1056 that extends toward the longitudinal axis of the device distal end 1000. The distal hook 1056 has a distal-facing surface 1057 that can electrosurgically treat tissue at the very distal tip of the probe. The distal-facing surface 1057 can have a more squared-off lateral extent than the distal-facing surface 578 of the hook, which can add structural integrity to the distal hook 1056. The distal hook 1056 is configured to secure the active electrode 1050 to a spacer 1080 at its distal-most end.

[0063] 10B shows an exploded view of the components of the distal tip 1000, including the inner sleeve 310, the outer sleeve 1010, which may define a portion of the return electrode 360, the insulating spacer 1060, the clip 1090, which may further define a portion of the return electrode 360, and the active electrode 1050. Embodiment 1000 is similar to embodiment 500 for most components, except as noted. For example, in embodiment 1000, the distal hook 1056 engages the spacer 1060 at its distal end with a proximally extending flange 1059. The spacer 1060 has a corresponding cavity 1062 and notch 1064 for receiving and engaging the hook 1056, as shown in more detail in FIG. 10E.

[0064] 10E, a proximally extending flange or protrusion 1059 is shown. The spacer 1060 includes a contoured cavity 1062 extending to and including the spacer's most distal surface, the cavity 1062 configured to receive the distal hook 1056 therein and engage the protrusion 1059. The distal hook 1056 is at least partially recessed within the cavity 1062 to anchor the active electrode 1050, while the surface 1057 allows access to tissue at the distal tip of the probe. The cavity 1062 includes a proximally extending notch 1064 configured to receive the protrusion 1059. The notch 1064 is configured to receive and engage the protrusion 1059 to anchor the distal end of the active electrode 1050 and mechanically resist separation of the active electrode 1050 from the spacer 1060 during use of the probe. The notch 1064 and cavity 1062 are also configured to limit the axial location of the active electrode portion 1052. The notch 1064 and cavity 1062 cooperate with the active electrode 1050 to space the proximal edge 1053 of the active electrode's treatment portion 1052 a predetermined axial distance from the spacer distal edge 1066. During assembly, the active electrode 1050 can be slid proximally along the spacer 1060 to lie along the spacer. The active electrode 1050 slides proximally until the protrusion 1059 is disposed within the cavity 1062 and engages the proximal surface of the notch 1064. The active electrode 1050 can then be fixed in place via, for example, an adhesive. This location defines an axial spacing between the edges 1066 and 1053 that is configured to avoid stress transfer to the spacer 1060 due to bending and flexing of the active electrode during use. During use of the device, under normal conditions, distal end 1000 may fold and bend. Figure 10C shows the top side of distal end 1000, showing tapered active electrode portion 1052 with squared-off distal-facing surface 1057a.

[0065] Those skilled in the art will appreciate that the present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The foregoing examples are therefore to be considered in all respects as illustrative and not limiting of the disclosure described herein. The scope of the disclosure is, therefore, indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. [Additional note 1] 1. A tissue ablation probe for mechanically ablating and electrosurgically treating tissue, comprising: an electrically conductive tubular distal end having a cutting window on a first circumferential side; an electrically insulating spacer wrapped around a second circumferential side of the tubular distal end; an active electrode fixed to the insulating spacer, the active electrode defining two portions angularly offset from one another, the two portions including a first portion extending circumferentially and axially along the tubular distal end and a second portion extending from a distal end of the first portion across the tubular distal end, the second portion having at least one flange configured to engage a notch in the electrically insulating spacer to resist separation of the active electrode from the electrically insulating spacer. [Additional note 2] 2. The tissue ablation probe of claim 1, wherein the second portion extends perpendicular to the longitudinal axis. [Additional note 3] 2. The tissue ablation probe of claim 1, wherein the second portion defines the distal-most surface of the tissue ablation probe. [Additional note 4] 2. The tissue excision probe of claim 1, wherein the first portion is axially tapered and configured to precisely incise tissue at the distal end of the first portion. [Additional note 5] 2. The tissue ablation probe of claim 1, wherein the at least one flange extends proximally into the electrically insulating spacer. [Additional note 6] 2. The tissue ablation probe of claim 1, wherein the at least one flange includes a bilateral flange. [Additional note 7] 10. The tissue ablation probe of claim 1, wherein the second portion defines a distally facing concave surface configured to deflect external forces on the active electrode during use. [Additional note 8] 2. The tissue excision probe of claim 1, wherein the insulating spacer extends around the tubular distal end to the cutting edge of the cutting window. [Additional note 9] 2. The tissue ablation probe of claim 1, wherein the insulating spacer extends over and covers the distally facing end surface of the tubular distal end, thereby defining at least a portion of the most distal end of the tissue ablation probe. [Additional Note 10] 2. The tissue ablation probe of claim 1, wherein the active electrode includes a neck extending proximally from a first portion of the active electrode configured to extend along a tunnel through the insulating spacer, thereby holding the active electrode in a second position proximally separated from the second portion. [Additional Note 11] 10. The tissue ablation probe of claim 1, further comprising a retaining clip extending around an outer surface of the insulating spacer and electrically and mechanically coupled to the tubular distal end. [Additional Note 12] 12. The tissue excision probe of claim 11, wherein the tubular distal end and the retaining clip together define an outer surface of the tissue excision probe. [Additional Note 13] 13. The tissue ablation probe of claim 12, wherein the retaining clip includes a distally extending tab disposed adjacent to the active electrode, the distally extending tab configured to align the proximal end of the active electrode and the retaining clip according to a target spacing, thereby improving electrosurgical tissue effects. [Additional Note 14] 12. The tissue excision probe of claim 11, wherein the retaining clip includes opposing radially recessed ends. [Additional Note 15] 2. The tissue ablation probe of claim 1, wherein the at least one flange is configured to engage with the notch and, concomitantly, to axially position the active electrode to maintain an axial gap between the insulating spacer and the proximal end of the active electrode, the axial gap being configured to reduce stress concentrations along the tubular distal end during use. [Additional Note 16] 1. A tissue ablation probe for mechanically ablating and electrosurgically treating tissue, comprising: a tubular distal end defining a return electrode, said tubular distal end comprising: an aperture having a cutting edge disposed on a first circumferential side of the tubular distal end; an insulating spacer wrapped around a second circumferential side of the tubular distal end opposite the aperture; an active electrode supported by the insulating spacer, the active electrode having a first portion extending axially and circumferentially along the tubular distal end and a retention hook extending from and angularly offset from a distal end of the first portion, the retention hook configured to secure the insulating spacer and the active electrode and to resist separation of the active electrode from the insulating spacer. [Additional Note 17] 17. The tissue ablation probe of claim 16, wherein the retention hook defines a distally facing surface of the tissue ablation probe. [Additional Note 18] 17. The tissue excision probe of claim 16, wherein the retaining hook includes a first protrusion extending toward the longitudinal axis of the tissue excision probe and a flange protrusion extending from the first protrusion configured to fit within a notch in the distal end of the insulating spacer. [Additional Note 19] 20. The tissue ablation probe of claim 18, wherein the flange protrusion extends along the longitudinal axis. [Additional Note 20] 1. A tubular end effector for a combination electrosurgical and mechanical ablation assembly, comprising: a metallic component defining a cutting window on a first circumferential side of the tubular end effector, the metallic component being configured as a return electrode; a ceramic spacer fixedly coupled to the metal component so as to form a second circumferential side of the tubular end effector opposite the first circumferential side, the distal end of the ceramic spacer including a groove; and a tubular end effector comprising: an active electrode fixed to the ceramic spacer, the active electrode positioned opposite the cutting window, the active electrode including a circumferential treatment surface and a retention hook extending from a distal end of the circumferential treatment surface and angularly offset therefrom, the retention hook including at least one protrusion for operably coupling within the groove, thereby retaining the active electrode on the tubular end effector.

Claims

1. 1. A tissue ablation probe for mechanically ablating and electrosurgically treating tissue, comprising: an electrically conductive tubular distal end having a cutting window (520) on a first circumferential side; an electrically insulating spacer (580) wrapped around a second circumferential side of said tubular distal end; an active electrode (570) fixed to the insulating spacer (580), the active electrode (570) defining two portions angularly offset from one another, the two portions including a first portion (571) extending circumferentially and axially along the tubular distal end, and a second portion (578) extending from a distal end of the first portion across the tubular distal end (500); Equipped with the second portion (578) having at least one flange (595) configured to engage a notch (581) in the electrically insulating spacer (580) to resist forces acting to lift and separate the active electrode (570) from the electrically insulating spacer (580); A tissue ablation probe, wherein the second portion (578) defines at least a portion of a distal-most surface of the tissue ablation probe.

2. The tissue ablation probe of claim 1 , wherein the second portion extends perpendicular to the longitudinal axis.

3. The tissue ablation probe of claim 1 , wherein the first portion (571) is axially tapered and configured to precisely incise tissue at a distal end of the first portion.

4. The tissue ablation probe of claim 1 , wherein at least one of the flanges extends proximally into the electrically insulating spacer (580).

5. The tissue ablation probe of claim 1 , wherein the at least one flange comprises a bilateral flange.

6. The tissue ablation probe of claim 1 , wherein the second portion (578) defines a distally facing concave surface configured to deflect external forces on the active electrode (570) during use.

7. The tissue ablation probe of claim 1 , wherein the insulating spacer (580) extends around the tubular distal end to a cutting edge of the cutting window.

8. 2. The tissue ablation probe of claim 1, wherein the insulating spacer (580) extends over and over a distal-facing end surface of the tubular distal end, thereby defining at least a portion of the most distal end of the tissue ablation probe.

9. 2. The tissue ablation probe of claim 1, wherein the active electrode (570) includes a neck extending proximally from the first portion (571) of the active electrode configured to extend along a tunnel (587) through the insulating spacer (580) to thereby hold the active electrode (570) in a second position proximally separated from the second portion (578).

10. The tissue ablation probe of claim 1 , further comprising a retaining clip (590) extending around an outer surface of the insulating spacer (580) and electrically and mechanically coupled to the tubular distal end.

11. The tissue ablation probe of claim 10 , wherein the tubular distal end and the retaining clip (590) together define an outer surface of the tissue ablation probe.

12. 12. The tissue ablation probe of claim 11, wherein the retaining clip includes a distally extending tab disposed adjacent the active electrode, the distally extending tab configured to align the proximal end of the active electrode and the retaining clip according to a target spacing, thereby improving electrosurgical tissue effects.

13. The tissue ablation probe of claim 10, wherein the retaining clip (590) includes opposing radially recessed ends (592a, 592b).

14. 2. The tissue ablation probe of claim 1, wherein at least one of the flanges is configured to engage the notch and concomitantly axially position the active electrode (570) to maintain an axial gap between the insulating spacer (580) and a proximal end of the active electrode (570), the axial gap being configured to reduce stress concentrations along the tubular distal end during use.

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