Patent Publication Number: US-2021177501-A1

Title: Medical devices and related methods

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of priority from Chinese Patent Application No. 201911302755.6, filed on Dec. 17, 2019, which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     Aspects of the present disclosure generally relate to medical devices and related methods. In particular, aspects of the present disclosure relate to medical devices and related methods configured for the treatment of tissue by delivering electrical energy to or into tissue and/or injecting fluid into and/or under tissue with an electrode having an insulated distal tip. 
     BACKGROUND 
     Medical devices, such as endoscopes or other suitable insertion devices, are employed for a variety of types of diagnostic and surgical procedures, such as endoscopy, laparoscopy, arthroscopy, gynoscopy, thoracoscopy, cystoscopy, etc. Many of these procedures involve delivering energy to tissue of an organ or a gland to treat tumors, infections, and the like. Examples of such procedures include Endoscopic Mucosal Resection (EMR), Endoscopic Sub-mucosal Resection (ESR), Endoscopic Sub-mucosal Dissection (ESD), polypectomy, mucosectomy, etc. In particular, such procedures may be carried out by inserting an insertion device into a subject&#39;s body through a surgical incision, or via a natural anatomical orifice (e.g., mouth, vagina, or rectum), and performing the procedure or operation at a target site with an auxiliary device inserted through the insertion device. 
     At times, during a medical procedure, a user may use an injection needle and an energy delivery device for purposes of raising, separating, flushing, cutting, dissecting, ablating, marking, coagulating, cauterizing, or otherwise treating and/or manipulating tissue. The injection and energy delivery may be performed separately. For example, in order to deliver energy to the tissue, the user may be required to remove the injection needle from the insertion device and deliver the energy delivery device through the insertion device to the tissue being targeted, and vice versa. During the procedure, the user may alternate using the injection needle and the energy delivery device, and exchanging devices may increase the duration and risks of the medical procedure. Additionally, one or more portions of the energy delivery device may inadvertently contact or harm tissue (or an inner channel of the insertion device) when energized. 
     The devices and methods of the current disclosure may rectify one or more of the deficiencies described above or address other aspects of the art. 
     SUMMARY 
     Examples of the present disclosure relate to, among other things, medical devices configured for treating tissue by delivering electrical energy to the tissue, and configured for delivering fluid into and/or under the tissue. Each of the examples disclosed herein may include one or more of the features described in connection with any of the other disclosed examples. 
     In one example, a medical device may include an electrode shaft and an insulation tip. The electrode shaft may be configured to deliver energy to a target site and may include an electrode shaft lumen configured to deliver fluid to the target site. The insulation tip may be coupled to a distal tip of the electrode shaft. The insulation tip may include an insulation tip lumen fluidly connected to the electrode shaft lumen and may be configured to deliver fluid to the target site. The insulation tip may cover an entirety of the distal tip of the electrode shaft. 
     The medical device may include one or more of the following features. The insulation tip may include a rounded distal end and a cylindrical side portion. The rounded distal end may be hemispherical and may extend distally beyond the distal tip of the electrode shaft. The insulation tip lumen may include a wide portion configured to receive a portion of the distal tip of the electrode shaft and a narrow portion extending distally beyond the distal tip of the electrode shaft. The narrow portion of the insulation tip lumen may include a cross-sectional width equal to a cross-sectional width of the electrode shaft lumen, and the narrow portion may include a chamfered distal end portion. The electrode shaft lumen and the insulation tip lumen may extend along a longitudinal axis of the medical device. 
     The insulation tip may be coupled to the electrode shaft via solder. A radially interior portion of the insulation tip may include a gap configured to receive at least a portion of the solder. The insulation tip may be coupled to the electrode shaft via brazing. When the insulation tip is coupled to the electrode shaft, a filler material may occupy a space at a junction between a portion of the electrode shaft and a portion of the insulation tip. 
     The insulation tip may include two insulation tip halves that are coupled together to couple the insulation tip to the electrode shaft. The electrode shaft may include a widened distal portion. Each of the two insulation tip halves may include a groove to receive at least a portion of the widened distal portion when the insulation tip halves are coupled to the electrode shaft. The groove in each of the two insulation tip halves may be positioned between the wide portion of the insulation tip lumen configured to receive the portion of the distal tip of the electrode shaft and the narrow portion of the insulation tip lumen extending distally beyond the distal tip of the electrode shaft. 
     The electrode shaft may include a first longitudinal portion, a second longitudinal portion proximal of the first longitudinal portion, and a transition portion between the first longitudinal portion and the second longitudinal portion. The first longitudinal portion may include a cross-sectional width less than a cross-sectional width of the second longitudinal portion. The electrode shaft may be formed of stainless steel, and the insulation tip may be formed of a ceramic or polymer material. 
     In another example, a medical device may include a handle including a fluid port and an energy receiving hub. The medical device may also include a shaft including a shaft lumen configured to direct a flow of fluid through the shaft from the fluid port. The medical device may also include a conductive element and an electrode. The conductive element may be electrically connected to the energy receiving hub and may pass through at least a portion of the handle and/or the shaft. The electrode may be coupled to a distal end of the shaft and include an electrode shaft and an insulation tip coupled to a distal tip of the electrode shaft. The electrode shaft may be electrically connected to the conductive element and may include an electrode shaft lumen fluidly connected to the shaft lumen. The insulation tip may include an insulation tip lumen fluidly connected to the electrode shaft lumen and may be configured to deliver fluid from a distal end of the electrode. The insulation tip may cover an entirety of the distal tip of the electrode shaft. 
     The medical device may include one or more of the following features. The handle may further include a main body and a movable body. Movement of the movable body relative to the main body may move the electrode relative to the distal end of the shaft. With the movable body in a proximally retracted position, only the insulation tip may be exposed distally beyond the shaft. With the movable body in a distally extended position, the insulation tip and at least a portion of the electrode shaft may be exposed distally beyond the shaft. 
     In yet another example, a medical device may include an electrode shaft and an insulation tip. The electrode shaft may include an electrode shaft lumen configured to receive fluid. The insulation tip may be coupled to a distal tip of the electrode shaft. The insulation tip may include a rounded distal portion that extends distally beyond the electrode shaft. The insulation tip may include an insulation tip lumen fluidly connected to the electrode shaft lumen to form a channel. The channel may extend along a longitudinal axis of the medical device. 
     The medical device may include one or more of the following features. The insulation tip may be coupled to the electrode shaft by soldering or brazing. The insulation tip may include two insulation tip halves that are coupled together to couple the insulation tip to the electrode shaft. The electrode shaft may include a widened distal portion, and each of the two insulation tip halves may include a groove to receive at least a portion of the widened distal portion when the insulation tip halves are coupled to the electrode shaft. 
     It may be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary aspects of the present disclosure and together with the description, serve to explain the principles of the disclosure. 
         FIG. 1A  illustrates an exemplary medical device, and  FIG. 1B  illustrates a cross-sectional view of the medical device with a distal portion of the medical device enlarged, according to aspects of this disclosure. 
         FIG. 2A  illustrates a side view of an electrode portion of the medical device of  FIGS. 1A and 1B , and  FIG. 2B  illustrates a cross-sectional view of the electrode portion of  FIG. 2A , according to aspects of the present disclosure. 
         FIG. 3A  illustrates a side view of an alternative exemplary electrode portion of the medical device of  FIGS. 1A and 1B , and  FIG. 3B  illustrates a cross-sectional view of the electrode portion of  FIG. 3A , according to aspects of the present disclosure. 
         FIG. 4A  illustrates a side view of a further alternative exemplary electrode portion of the medical device of  FIGS. 1A and 1B , according to aspects of the present disclosure.  FIG. 4B  illustrates a partially exploded view of the electrode portion of  FIG. 4A , and  FIG. 4C  illustrates a cross-sectional view of the electrode portion of  FIG. 4A . 
     
    
    
     DETAILED DESCRIPTION 
     Examples of the present disclosure include devices and methods for: facilitating and improving the efficacy, efficiency, and safety of treating and/or manipulating tissue when, for example, applying electrical energy to tissue with an electrode; delivering fluid into and/or under tissue during a medical procedure through the distal end of the electrode; and insulating a distal tip of the electrode. For example, aspects of the present disclosure may provide a user (e.g., physician, medical technician, or other medical service provider) with the ability to apply electrical energy or heat to tissue using a medical device having an electrode, and to deliver fluid into and/or under tissue with the same medical device. Aspects of the present disclosure may provide the user with the ability to apply electrical energy or heat and deliver fluid with a reduced likelihood of damaging tissue or contacting unintended portions of the tissue. Some aspects of the present disclosure may be used in performing an endoscopic, laparoscopic, arthroscopic, gynoscopic, thoracoscopic, cystoscopic, or other type of procedure. 
     Reference will now be made in detail to examples of the present disclosure described above and illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     The terms “proximal” and “distal” are used herein to refer to the relative positions of the components of an exemplary medical device. When used herein, “proximal” refers to a position relatively closer to the exterior of the body of a subject or closer to a user, such as a medical professional, holding or otherwise using the medical device. In contrast, “distal” refers to a position relatively further away from the medical professional or other user holding or otherwise using the medical device, or closer to the interior of the subject&#39;s body. As used herein, the terms “comprises,” “comprising,” “having,” “including,” or other variations thereof, are intended to cover a non-exclusive inclusion, such that a device or method that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent thereto. Unless stated otherwise, the term “exemplary” is used in the sense of “example” rather than “ideal.” As used herein, the terms “about,” “substantially,” and “approximately,” indicate a range of values within +/−10% of a stated value. 
       FIGS. 1A and 1B  depict a medical device  10  that includes a handle  12 , a shaft  14 , and a distal end  16 . Handle  12  may include a main body  18  and a movable body  20 . Handle  12  also may include a port  22  configured to receive fluid, and a hub  24  configured to receive electrical energy similar to an electrical plug or socket. Distal end  16  includes an end effector, for example, an electrode portion  26  (hereinafter “electrode  26 ”). Electrode  26  is electrically connected to hub  24 , and as discussed in detail below, may include a channel fluidly connected to, or otherwise in fluid communication with, port  22 . Additionally, as shown in  FIG. 1B  and discussed in detail below, electrode  26  may include an insulation tip  28 , which may at least partially surround a distal portion of an electrode shaft  30 . 
     Medical device  10  may be inserted into a body lumen of a subject, either through an insertion device (not shown) or alone, such that at least a portion of shaft  14  may be within the subject, while handle  12  may remain outside of the subject. Distal end  16  may be positioned at a target site within the subject. From outside of the subject, a user can manipulate handle  12 . Movement of movable body  20  relative to main body  18  in a first direction (e.g., the distal direction) may extend electrode  26  relative to shaft  14  (e.g., move electrode  26  distally relative to a distal end of shaft  14 ), while movement of movable body  20  relative to main body  18  in a second direction (e.g., the proximal direction) may retract electrode  26  relative to shaft  14  (e.g., move electrode  26  proximally relative to a distal end of shaft  14 ). Although not shown, movable body  20  or additional components of handle  12  may articulate electrode  26  (or electrode  26  and distal end  16 ) left or right, and/or up or down relative to shaft  14 . 
     Handle  12  may be coupled to a fluid source (not shown) via port  22 . Port  22  may be in fluid communication with electrode  26  via an internal lumen  31 , which may extend through handle  12  ( FIG. 1B ) and shaft  14 . It is noted that various portions of handle  12  shown in  FIG. 1B  may not be to scale, in order to more fully illustrate various portions of handle  12 . In one aspect, internal lumen  31  may extend longitudinally through main body  18  of handle  12  and shaft  14  to fluidly connect port  22  to electrode  26 . Port  22  may be positioned on a proximal portion of main body  18 , for example, a proximal end of main body  18 . Alternatively, port  22  may be positioned on a distal or central portion of main body  18 . Moreover, port  22  may include a one-way valve, a luer, a seal, threading, and/or any appropriate element to help maintain a secure connection between handle  12  and the fluid source, minimize or prevent back-flow (e.g., fluid flowing proximally out of port  22 ), and/or minimize or prevent leakage. In one example, a one-way valve may include an outer housing containing an inner elastomeric and/or gelatinous sealing member (not shown). 
     Handle  12  may be coupled to an energy source (not shown) through hub  24 . Hub  24  may include one or more prongs or pins  32  to couple to the energy source. Hub  24  may be electrically coupled to electrode  26  via a conductive element  33 , which may be electrically coupled to pin  32  and extend through handle  12  and through at least a portion of shaft  14 . The energy source may be an electrocautery source, a radio frequency generator, a heating source, a current generator, etc. In one aspect, medical device  10  may be used for monopolar electrosurgery, and may include a return electrode positioned remotely from electrode  26  on or otherwise adjacent the subject. In another aspect, medical device  10  may be used for bipolar electrosurgery. In that instance, electrode  26  may include an active electrode portion, and a return electrode may be provided at or near another portion of electrode  26  and/or shaft  14 . In one example, although not shown, two conductive elements may run through shaft  14 , where the conductive elements may be electrically isolated from each other, allowing one to conduct energy to the active electrode and the other to conduct energy from a return electrode. 
     Hub  24  may be positioned on main body  18 , for example, on a proximal end of main body  18 . In one aspect, port  22  may extend from the proximal end of main body  18  in a direction parallel to a longitudinal axis of main body  18 , and hub  24  may extend from the proximal end of main body  18  at an angle transverse (e.g., approximately 45 degrees) to the longitudinal axis of main body  18 . In another aspect, hub  24  may be positioned on a distal or central portion of main body  18 , or on movable body  20 . Although not shown, main body  18  and/or hub  24  may include a one-way valve, a luer, a seal, threading, and/or any appropriate element to help maintain a secure connection between handle  12  and the energy source, minimize or prevent back-flow (e.g., fluid flowing from port  22  and/or internal lumen  31  and proximally out of hub  24 ), and/or minimize or prevent leakage. 
     In one aspect shown in  FIG. 1B , pin  32  may extend through hub  24  transverse to a longitudinal axis of handle  12 , and may be electrically and physically connected to conductive element  33 , such as a wire, a cable, and/or a braided sheath. Conductive element  33  may be electrically conductive or include an electrically conductive element, and conductive element  33  may extend longitudinally through internal lumen  31  and through shaft  14 . As shown in  FIG. 1B , fluid delivered through port  22  may surround at least a portion of conductive element  33 . In one aspect, conductive element  33  may include one or more layers of insulation to help insulate conductive element  33  from the fluid in internal lumen  31 . As alluded to above, a second conductive element (not shown) may be provided as a return pathway where medical device  10  has a bipolar configuration. Although not shown, in another aspect, the energy source may be a part of handle  12  (e.g., an internal battery in handle  12 ). 
     As mentioned, handle  12  may control the extension or retraction of electrode  26  relative to the distal end  16  of shaft  14 . For example, main body  18  may include a slot  34 , and movable body  20  may be slidably positioned within slot  34 . For example, main body  18  may be configured to be held by a user&#39;s hand, and movable body  20  may be configured to be controlled by the movement of the user&#39;s thumb. For example, a side of main body  18  opposite to movable body  20  may include one or more contours  36 , which may help the user grip main body  18 . Additionally, movable body  20  may include one or more ridges  37 , which may help the user manipulate movable body  20 . Movable body  20  may be lockable in one or more positions relative to main body  18 , and/or may be spring-biased in a direction (e.g., toward a proximally retracted position). 
     Movable body  20  may be coupled to a drive element, and the drive element may impart distal or proximal movement to at least a portion of electrode  26  based on relative movement between main body  18  and movable body  20 . In one aspect, conductive element  33  may also act as a drive wire, rod, cable, or the like, such that conductive element  33  imparts distal or proximal movement to at least a portion of electrode  26  while also coupling electrode  26  to hub  24 , e.g., the one or more pins  32 , to deliver the energy to (and/or from) electrode  26 . As shown in  FIG. 1B , movable body  20  may be coupled to conductive element  33  via a coupling mechanism, for example, a coupler  38 . In one aspect, coupler  38  may be physically coupled (either directly or indirectly) to movable body  20 , and may also be physically coupled (either directly or indirectly) to conductive element  33  such that movement of movable body  20  extends or retracts conductive element  33 , and thus extends or retracts electrode  26 . It is noted that coupler  38  and/or other components within handle  12  may help maintain the electrical connection between pin  32  and conductive element  33  when conductive element  33 , and thus electrode  26 , is in the retracted or extended positions. Alternatively, in another aspect, coupler  38  and/or other components within handle  12  may be configured to only electrically connect pin  32  and conductive element  33  when conductive element  33 , and thus electrode  26 , is in the extended position, or an at least partially extended position. 
     As shown in  FIG. 1A , handle  12  may also include one or more indicators, for example, indicators  39 A,  39 B. For example, indicators  39 A,  39 B may visually indicate to the user the position of electrode  26  relative to shaft  14 . The position of indicators  39 A,  39 B may also correspond with the position of movable body  20 . For example, indicator  39 A may be positioned on handle  12  at a position corresponding with a retracted position of movable body  20 , and may indicate that electrode  26  is retracted relative to shaft  14 . Similarly, indicator  39 B may be positioned on handle  12  at a position corresponding with an extended position of movable body  20 , and may indicate that electrode  26  is extended relative to shaft  14 . 
     As shown in  FIGS. 1A and 1B , shaft  14  extends from a distal portion of main body  18  to distal end  16 , and may surround at least a portion of electrode  26 . Shaft  14  may be a sheath that surrounds at least a portion of one or more lumens (e.g., lumen  31 ) and the drive wire (e.g., conductive element  33 ). In another aspect, shaft  14  may be an extrusion that includes one or more lumens extending from handle  12  to distal end  16 . 
     The enlarged portion of  FIG. 1B  illustrates additional features of shaft  14  and distal end  16 . Electrode  26  includes insulation tip  28  surrounding a distal portion of electrode shaft  30 . Electrode  26  may be positioned within a portion of an end cap  42  of distal end  16 . End cap  42  may include a distal end face  44  and graduated surfaces  46 ,  48 , and  50 . For example, a first graduated surface  46  may be at a distalmost portion of end cap  42 . As shown in  FIG. 1B , with shaft  14  coupled to distal end  16 , first graduated surface  46  of end cap  42  may be exposed distally beyond shaft  14 , while a second graduated surface  48  may be received in shaft  14 . A third graduated surface  50  may, for example, be tapered to facilitate insertion of end cap  42  into shaft  14 . In another example, shaft  14  may fully enclose the radially exterior portions of end cap  42 . End cap  42  may be at least partially electrically insulating. For example, end cap  42  may be formed of a ceramic material or another non-conductive material. Alternatively, only distal end face  44  and an internal portion of end cap  42  that contacts and/or surrounds electrode  26  may be electrically insulating. Distal end face  44  includes a central opening  52  through which electrode  26  may extend and retract. 
     Electrode  26  may be coupled to a proximal support  54  of distal end  16 , which may include a cylindrical extension  56 . Proximal support  54  may be coupled to a portion of the drive wire (e.g., conductive element  33 ) via a drive wire receiving portion  58 . Cylindrical extension  56  may extend distally and may receive at least a portion of electrode  26 . Electrode  26  and cylindrical extension  56  may be coupled via welding, an adhesive, crimping, friction fit, or other appropriate coupling. In one aspect, cylindrical extension  56  may allow for different electrodes  26  to be removably coupled to distal end  16 . Proximal support  54  includes a support lumen  70 , and support lumen  70  fluidly connects port  22  to electrode  26 , for example, via a lumen (e.g., lumen  31 ) through shaft  14 . 
     Proximal support  54  includes a proximal coupling portion  72 , which includes drive wire receiving portion  58 . Drive wire receiving portion  58  may be an indentation that extends parallel to at least a portion of support lumen  70 . Drive wire receiving portion  58  may receive a portion of a drive wire (not shown), and the drive wire and/or an inner sheath  40  may be coupled to movable body  20  such that the movement of movable body  20  imparts distal or proximal movement to proximal support  54  and, thus, to electrode  26 . The drive wire may be coupled to drive wire receiving portion  58  within coupling portion  72  by welding, an adhesive, crimping, friction fit, or any other permanent or temporary coupling. Proximal support  54  may also be coupled to electrode  26  by welding, an adhesive, crimping, friction fit, or any other permanent or temporary coupling. In one aspect, both the drive wire and proximal support  54  are conductive to electrically connect the one or more prongs  32  of hub  24  to electrode  26 . In another aspect, proximal support  54  may be at least partially insulating, and may include a wire or other conductive element electrically connecting the drive wire to electrode  26 . Similarly, in one aspect, the drive wire may be at least partially insulating and may include a wire or other conductive element. Furthermore, at least a portion of the drive wire may be positioned within inner sheath  40 . Alternatively, the drive wire may be positioned within a separate lumen in shaft  14  (e.g., a lumen separate from the lumen running through inner sheath  40 ). 
     End cap  42  includes a central portion  74  through which electrode shaft  30  may move during the extension and retraction. End cap  42  may also include a narrowing portion or stop surface  76  at a distal end of central portion  74 . Electrode shaft  30  may include a transition portion  78  between a first longitudinal portion  80  and a second longitudinal portion  82 . Stop surface  76  and transition portion  78  may limit the distal extension of electrode  26  through end cap  42 . In a fully extended position, first longitudinal portion  80  may protrude from end cap  42  and may form an exposed portion that may be used for cutting or otherwise treating tissue. Additionally, although not shown, end cap  42  may be fixedly coupled to shaft  14  via welding, an adhesive, crimping, friction fit, or other appropriate coupling. 
     Electrode  26  and proximal support  54  may be movable relative to end cap  42  in response to the relative movement of movable body  20  and main body  18  of handle  12 . For example, with movable body  20  in a proximal position relative to main body  18 , electrode shaft  30  may be substantially retracted within end cap  42  with only a distal portion of electrode  26  (e.g., insulation tip  28 ) extending distally beyond end cap  42 . Then, as movable body  20  is translated distally relative to main body  18 , electrode  26  and proximal support  54  translate distally relative to end cap  42  such that a greater portion of electrode  26  (e.g., electrode shaft  30 ) extends distally beyond end cap  42  through central opening  52 . 
     Alternatively, although not shown, central opening  52  may be larger than insulation tip  28 , and with movable body  20  in the proximalmost position, electrode  26  (including insulation tip  28 ) may be fully retracted within central opening  52  of end cap  42 . Furthermore, in one aspect, movable member  20  may have an equilibrium position relative to main body  18 , and the equilibrium position may correspond to electrode shaft  30  being partially extended from end cap  42 . 
     As shown in the enlarged portion of  FIG. 1B , electrode shaft  30  includes a distal tip  60  and a longitudinal portion  62 . Distal tip  60  and longitudinal portion  62  may be formed by first longitudinal portion  80 . Distal tip  60  may be received within insulation tip  28  and covered by insulation tip  28 , and longitudinal portion  62  may be proximal to insulation tip  28  and not covered by insulation tip  28 . 
     Electrode shaft  30  also includes an electrode shaft lumen  64  extending through electrode shaft  30 , for example, extending longitudinally through a central portion of electrode shaft  30 . Electrode shaft lumen  64  may be in fluid communication with port  22  via support lumen  70  through proximal support  54 . In one aspect, inner sheath  40  may form at least a portion of the fluid connection between lumen  70  and port  22 . Additionally, electrode shaft lumen  64  is in fluid communication with an insulation tip lumen  28 C to form a channel to deliver fluid from a distal end of electrode  26 . 
     As shown in  FIG. 1B , insulation tip  28  may include a distal end  28 A and a side portion  28 B. Distal end  28 A may be rounded, for example, substantially hemispherical, and side portion  28 B may include straight sides, for example, may be substantially cylindrical. In one aspect, the shapes of distal end  28 A and side portion  28 B may help distal end  16  be atraumatic, and/or may help abut, position, manipulate, or otherwise treat tissue, while electrode  30  may be used to cut, dissect, ablate, mark, coagulate, cauterize, or otherwise treat tissue. Nevertheless, this disclosure is not so limited, and insulation tip  28 , including distal end  28 A and side portion  28 B, may include other shapes. For example, insulation tip  28  may be frustoconical, tapered, chamfered, filleted, beveled, or combinations thereof. In one aspect, insulation tip  28  completely surrounds or covers a distal portion (e.g. distal tip  60 ) of electrode shaft  30 . For example, insulation tip  28  may cover approximately one quarter of a length of first longitudinal portion  80  of electrode shaft  30 . In another example, insulation tip  28  may cover approximately one third or one half of the length of first longitudinal portion  80  of electrode shaft  30 . In this aspect, insulation tip  28  may provide an insulation from the distal portion of electrode shaft  30  and at least a portion of the tissue near insulation tip  28 . For example, insulation tip  28  may abut tissue, and electrode shaft  30  may be energized while insulation tip  28  helps to insulate the tissue that insulation tip  28  abuts against. Moreover, insulation tip  28  may receive distal tip  60  within approximately one half of insulation tip  28  along the longitudinal axis, which may help securely couple insulation tip  28  and electrode  30 . Additionally, approximately one half of insulation tip  28  may extend distally beyond distal tip  60 , which may help insulate tissue abutting distal postion  28 A of insulation tip  28  when electrode  30  is energized. 
     As discussed below, insulation tip  28  and electrode shaft  30  may be physically coupled, for example, via one or more of soldering, brazing, welding, bonding, or one or more other coupling mechanisms. Moreover, insulation tip  28  and electrode shaft  30  form a fluid channel that extends through both electrode shaft  30  and insulation tip  28  in order to deliver (e.g., inject) fluid to a target site (e.g., within or between layers of tissue to raise, separate, flush, or otherwise treat tissue). Electrode shaft  30  may be energized, and the exposed portion of electrode shaft  30  (e.g., longitudinal portion  62 ) may be used to cut, dissect, ablate, mark, coagulate, cauterize, or otherwise treat tissue. 
       FIGS. 2A and 2B  illustrate additional aspects of electrode  26  that may form a portion of distal end  16  of medical device  10 .  FIG. 2A  shows a side view of electrode  26 , and  FIG. 2B  shows a cross-sectional view of electrode  26 . As mentioned, electrode  26  includes insulation tip  28  surrounding electrode shaft  30 . Insulation tip  28  may include distal portion  28 A and side portion  28 B. As shown in  FIGS. 1B and 2B , insulation tip  28  includes insulation tip lumen  28 C. In this aspect, fluid delivered through electrode shaft lumen  64  may be delivered distally through insulation tip lumen  28 C. In one aspect, electrode shaft lumen  64  and insulation tip lumen  28 C may be approximately the same size. In another aspect, electrode shaft lumen  64  and insulation tip lumen  28 C may be tapered distally such that distal portions of the lumens are narrower than proximal portions of the lumens. Alternatively, electrode shaft lumen  64  and insulation tip lumen  28 C may be tapered proximally such that proximal portions of the lumens are narrower than distal portions of the lumens. In these aspects, varying sizes of electrode shaft lumen  64  and insulation tip lumen  28 C may help increase or decrease the pressure of the fluid being delivered through the fluid channel. A distal end portion  28 D of insulation tip lumen  28 C may include a chamfer or angled portion, which may help disperse, direct, or otherwise deliver fluid to a target site with a decreased likelihood of damaging tissue. Additionally, distal end  28 A of insulation tip  28  may include an internal face  28 E. When insulation tip  28  and electrode  30  are coupled together, the distal end face of electrode  20  may abut internal face  28 E. 
     As mentioned, electrode shaft  30  may include transition portion  78 , first longitudinal portion  80 , and second longitudinal portion  82 . In one aspect, a distal portion (e.g., first longitudinal portion  80 ) of electrode shaft  30  may include a consistent width. In another aspect, and as shown in  FIGS. 4B and 4C , the distal end of the distal portion of electrode shaft  30  may include an increased thickness (e.g., a widened end portion  292 ) relative to the remaining distal portion of electrode shaft  30 . 
     As shown in  FIG. 2B , insulation tip  28  may be coupled to a distal portion of electrode shaft  30  via a solder  66 . In one aspect, insulation tip  28  may include a gap  68  for example, a radial indentation or cutout, in a radial internal portion  28 F of insulation tip  28 . Gap  68  may occupy approximately a quarter of a longitudinal length of insulation tip  28 . In this aspect, insulation tip  28  may be coupled to electrode shaft  30  by placing melted solder  66  in gap  68 , and then inserting electrode shaft  30  into insulation tip  28 . The solder  66  may help couple insulation tip  28  and electrode shaft  30 . Additionally, as shown in  FIG. 2B , radial internal portion  28 F that forms insulation tip lumen  28 C may transition from a wider proximal lumen (e.g., where insulation tip  28  overlaps with electrode shaft  30 ) to a narrower distal lumen (e.g., wherein insulation tip  28  does not overlap with electrode shaft  30 ). In this aspect, the transition may correspond to the distal end of gap  68 , and may also help form a stop surface for the distal end face of distal tip  60  to abut internal face  28 E of insulation tip  28 . 
     Insulation tip  28  may be formed of a ceramic (e.g., zirconia, an alloy containing zirconium (e.g., ZrO 2 ), aluminum oxide (Al 2 O 3 ), a ceramic alloy, etc.) a polymer material (e.g., a fluoropolymer, polyether ether ketone (PEEK), etc.) or another medically-safe, heat-resistant, and non-conductive material. Electrode shaft  30  may be formed of a conductive material, for example, a stainless steel (e.g., 316L stainless steel), titanium, or another medically-safe and conductive material. In one aspect, electrode shaft  30  may include a surface finish, for example, may be passivated per ASTM A967 Nitric 2. 
     Although not shown, electrode  26  may include an electrode plate. The electrode plate may be positioned at the proximal face of side portion  28 B and/or may surround a portion of electrode shaft  30  just proximal to insulation tip  28 . In one aspect, the electrode plate may be conductive, and may be energized when electrode shaft  30  is energized. In another aspect, the electrode plate may not be conductive. In either aspect, the electrode plate may help support insulation tip  28  and/or electrode shaft  30 , and/or may help couple insulation tip  28  to electrode shaft  30 . 
     Various portions of insulation tip  28  may include heights and width, for example, as measured relative to a longitudinal axis of insulation tip  28 . Insulation tip  28  may include a width (e.g., at a proximal end of side portion  28 B) of approximately 2.0 to 3.0 mm, for example, approximately 2.2 mm. Insulation tip  28  may have a height (e.g., from the proximal end of side portion  28 B to a distal end face of distal end  28 A) of approximately 2.0 to 3.0 mm, for example, approximately 2.1 mm. For example, distal end  28 A of insulation tip  28  may be rounded (e.g., substantially hemispherical), and may include a radius of approximately 0.5 to 2.0 mm, for example, approximately 1.1 mm. Side portion  28 B may have a height of approximately 0.5 to 1.0 mm, for example, approximately 0.9 mm. If electrode  26  includes the electrode plate (not shown), the electrode plate may include a height of 0.05 to 0.2 mm, for example, approximately 0.1 mm. 
     Additionally, as shown in  FIG. 2B , the wider portion of insulation tip lumen  28 C formed by radial internal portion  28 F (e.g., where insulation tip  28  overlaps with electrode shaft  30 ) may include a height of approximately 0.5 to 1.5 mm, for example, approximately 1.0 mm, and the narrower portion of insulation tip lumen  28 C (e.g., wherein insulation tip  28  does not overlap with electrode shaft  30 ) may include a height of approximately 0.5 to 1.5 mm, for example, approximately 1.0 mm. The wider portion of insulation tip lumen  28 C formed by radial internal portion  28 F (e.g., where insulation tip  28  overlaps with electrode shaft  30 ) may include a width of approximately 0.3 to 0.7 mm, for example, approximately 0.5 mm, and the narrower portion of insulation tip lumen  28 C (e.g., wherein insulation tip  28  does not overlap with electrode shaft  30 ) may include a width of approximately 0.2 to 0.5 mm, for example, approximately 0.3 mm. As mentioned, distal end portion  28 D may include a chamfer or angled portion, which may transition from the width of the narrowed lumen, for example, approximately 0.3 mm, to a wider width, for example, approximately 0.37 mm. In this aspect, the chamfer or angled portion of distal portion  28 D may include an angle of approximately 60 degrees relative to the longitudinal axis. 
     Various portions of electrode shaft  30  may include heights and width, for example, as measured relative to a longitudinal axis of electrode shaft  30 . Electrode shaft  30  may include a total height of approximately 4.0 to 6.0 mm, for example, approximately 5.2 mm. First longitudinal portion  80  may include a height of approximately 2.0 to 4.0 mm, for example, approximately 3.0 mm. Second longitudinal portion  82  may include a height of approximately 1.0 to 2.0 mm, for example, approximately 1.7 mm. Transition portion  78  may include a height of approximately 0.2 to 1.0 mm, for example, approximately 0.5 mm. First longitudinal portion  80  may include a width of approximately 0.4 to 0.7 mm, for example, approximately 0.5 mm. Second longitudinal portion  82  may include a width of approximately 0.5 to 0.7 mm, for example, approximately 0.6 mm. In this aspect, transition portion  78  may include an angle of approximately 7 degrees relative to the longitudinal axis. In one aspect, electrode shaft lumen  64  and insulation tip lumen  28 C may be approximately the same width (e.g., in a direction transverse to the longitudinal axes of electrode shaft lumen  64  and insulation tip lumen  28 C). For example, electrode shaft lumen  64  and insulation tip lumen  28 C may include constant widths of approximately 0.3 mm. In this aspect, second longitudinal portion  82  may include a radial thickness (e.g., from a radial exterior to a radial interior that defines electrode shaft lumen  64 ) of approximately 0.5 mm, and first longitudinal portion  80  may include a radial thickness (e.g., from a radial exterior to a radial interior that defines electrode shaft lumen  64 ) of approximately 0.3 mm. 
       FIGS. 3A and 3B  illustrate views of another electrode  126  similar to electrode  26 , with similar elements shown by  100  added to the reference numbers. As shown, electrode  126  includes an insulation tip  128  and an electrode shaft  130 . Insulation tip  128  may include a distal portion  128 A, which may be rounded, and a side portion  128 B, which may be cylindrical. In the aspect shown in  FIGS. 3A and 3B , insulation tip  128  and electrode shaft  130  may be coupled via brazing, for example, by melting and flowing (e.g., by capillary action) a filler metal (e.g., aluminum-silicon, copper, copper-silver, copper-zinc (brass), copper-tin (bronze), gold-silver, a nickel alloy, silver, an amorphous brazing foil using nickel, iron, copper, silicon, boron, phosphorous, and/or other materials) between insulation tip  128  and electrode shaft  130 . Once insulation tip  128  and electrode shaft  130  are coupled, insulation tip  128  and electrode shaft  130  form a fluid channel through an electrode shaft lumen  164  and an insulation tip lumen  128 C in order to deliver fluid to a target site, as discussed above. Moreover, the exposed portion of electrode shaft  130  may be energized to treat tissue, while insulation tip  128  covers and insulates the distal portion of electrode shaft  130 , which may help prevent or minimize damage and/or unintended contact with tissue. 
     The filler metal (not shown) may have a lower melting point than the materials that form insulation tip  128  and electrode shaft  130 . In one aspect, insulation tip  128  may be placed over the distal portion of electrode shaft  130  (or electrode shaft  130  may be inserted into insulation tip  128 ) such that electrode shaft  130  abuts internal face  128 E of insulation tip  128 . Then, the filler metal, which has been heated, for example, to a temperature slightly above its melting temperature (e.g., its liquidus temperature), may be flowed over the outer face of electrode shaft  130  and/or the internal face of insulation tip  128 . In another example, the filler metal may be flowed over the outer face of electrode shaft  130  and/or the internal face of insulation tip  128 , and then insulation tip  128  may be placed over the distal portion of electrode shaft  130  (or electrode shaft  130  may be inserted into insulation tip  128 ) such that electrode shaft  130  abuts internal face  128 E of insulation tip  128 . In the above aspects, the cooling of the filler metal helps to physically couple insulation tip  128  and electrode shaft  130 . 
     It is noted that, in the aspects shown in  FIGS. 3A and 3B , insulation tip  128  may not include a gap  68 , as in insulation tip  28  of  FIGS. 2A and 2B . Instead, the filler metal may couple an internal face of insulation tip lumen  28 C to an outer face of electrode  130  at a junction  184 . In this aspect, junction  184  (or a space between the internal face of insulation tip lumen  28 C and the outer face of electrode shaft  130  that is filled by the filler material) may be approximately 0.1 mm or less, for example, approximately 0.03 to 0.08 mm. 
       FIGS. 4A-4C  illustrate views of another electrode  226  similar to electrode  26 , with similar elements shown by  200  added to the reference numbers. As shown, electrode  226  includes an insulation tip  228  and an electrode shaft  230 . 
     Insulation tip  228  may be formed of two halves  228 ′,  228 ″. Half  228 ′ may include a partially-rounded distal portion  228 A′ (e.g., a quarter of a sphere) and a partially cylindrical side portion  228 B′, and half  228 ″ may include a partially-rounded distal portion  228 A″ (e.g., a quarter of a sphere) and a partially-cylindrical side portion  228 B″. Halves  228 ′,  228 ″ may be divided along a longitudinal centerline  290 . For example, as shown in  FIG. 4B , halves  228 ′,  228 ″ may be separated. Halves  228 ′,  228 ″ may be positioned around the distal portion (e.g., distal tip  260 ) of electrode shaft  230  and may be bonded or joined together, for example, via soldering (which, although not shown, may include one or more gaps to receive the solder, as discussed with respect to  FIGS. 2A and 2B ), brazing as discussed with respect to  FIGS. 3A and 3B , welding, one or more adhesives, or any other coupling mechanism. In one aspect, joining halves  228 ′,  228 ″ around the distal portion of electrode shaft  230  may also couple halves  228 ′,  228 ″ (and thus insulation tip  228 ) to electrode shaft  230 . Alternatively or additionally, halves  228 ′,  228 ″, either individually or together, may be joined to electrode shaft  230  via any of the aforementioned coupling mechanisms. 
     In one aspect, as shown in  FIGS. 4B and 4C , the distal end of electrode shaft  230  may include widened end portion  292 . Halves  228 ′,  228 ″of insulation tip  228  may each include grooves  294  to receive at least a portion of widened end portion  292 . For example, widened end portion  292  may be a generally cylindrical extension that extends radially outward relative to a longitudinal axis of electrode  230 . In one aspect, widened end portion  292  may include a flat distal end and a curved proximal end. Halves  228 ′,  228 ″of insulation tip  228  may each include a groove  294  to receive respective portions (e.g., halves) of widened end portion  292 . Each groove  294  in halves  228 ′,  228 ″ may include a shape corresponding to the shape of widened end portion  292 . 
     Insulation tip  228  (as formed by joined halves  228 ′,  228 ″) may include an insulation tip lumen  228 C with a proximal portion  296  and a distal portion  298 . Grooves  294  may be positioned between proximal portion  296  and distal portion  298 . Proximal portion  296  may be wider than distal portion  298 . As shown in  FIGS. 4B and 4C , groove  294  may be wider (e.g., extend further radially away from the longitudinal axis of insulation tip  228 ) than proximal portion  296 . Distal portion  298  may be approximately the same width as an electrode shaft lumen  264 , and distal portion  298  and electrode shaft lumen  264  may form a fluid channel. Moreover, insulation tip lumen  228 C may terminate distally at the distal end portion  228 D, which may include a chamfer or angled portion, as mentioned above. Groove  294 , proximal portion  296 , and distal portion  298  may be sized to accommodate any shape or configuration of electrode  230 , such that distal tip  260  is receivable into insulation tip  228 . Additionally, in some aspects, portions of insulation tip  228  (e.g., groove  294  and proximal portion  296 ) may be sized to form a space between overlapping portions of insulation tip  228  and electrode  230 , for example, to help accommodate for differences in coefficients of thermal expansion between the materials of insulation tip  228  and electrode  230 . 
     Once insulation tip  228  and electrode shaft  230  are coupled, insulation tip  228  and electrode shaft  230  form the fluid channel through electrode shaft lumen  264  and insulation tip lumen  228 C in order to deliver fluid to a target site and/or to tissue from the distal end of electrode  226 , as discussed above. Moreover, the exposed portion of electrode shaft  230  may be energized to treat tissue, while insulation tip  228  covers the distal portion (e.g., distal tip  260 ) of electrode shaft  230 , which may help prevent or minimize damage and/or unintended contact with tissue. 
     The electrodes, including the insulation tips and electrode shafts, help to provide a standoff or insulation between a distal portion of the electrode and tissue at the target site. Additionally, the various electrodes may help to allow for a device that may be used to both cut, dissect, ablate, mark, or otherwise treat tissue, and also deliver fluid to the target site. The fluid may be delivered to the target site distally out of the distal end of the electrode. 
     The various electrodes discussed herein are capable of modifying physical properties of tissue when in contact with tissue by delivering energy (e.g., radio frequency energy). The energy delivered may be monopolar or bipolar energy. The various electrodes may be coupled to a shaft, with the shaft configured to extend into a body lumen or cavity of a subject. The shaft includes an electrical element traversing the shaft and connecting the electrode to an energy source, for example, in the handle or coupled to the handle. 
     As discussed, the electrodes may also be coupled to an actuation member (e.g., movable body  20 ), for example, in the handle or coupled to the handle, that allows a user to translate the electrode relative to the shaft. The electrode may be translatable between at least a first position in which a cutting shaft (e.g., longitudinal portion  62 ), of the electrode is retracted within the shaft, and a second position in which the cutting shaft is extended beyond the shaft and exposed. In both the first and second positions, the distal portion that includes the insulated portions (e.g., insulation tip  28 ) may be extended and exposed beyond the shaft, and not retracted within the shaft. Moreover, the handle may allow for the electrodes to be positioned in one or more intermediate position (i.e., a position in which only a portion of longitudinal portion  62  is exposed). 
     As such, the insulated distal end face (e.g., insulation tip  28 ) may abut tissue and help to prevent or minimize damage or unintended contact of the electrode with the tissue. The user may also position the uninsulated electrode shaft to abut or contact tissue and apply energy to cut, dissect, ablate, mark, or otherwise treat tissue. The insulation tips may be coupled to the electrode shaft in various ways, which may allow for the insulation tip to be coupled to an existing uninsulated electrode shaft and then used in a procedure. 
     In one example, an electrosurgical generator coupled to the handle (or within the handle) may generate receive energy in various modes, for example, radio frequency energy in a cutting mode, a coagulation mode, etc., in order for the electrode to deliver these different modes of energy to the tissue. In one aspect, the electrosurgical generator and/or the handle may include one or more knobs, dials, buttons, etc. in order to select the energy mode. Additionally, in one example, a fluid source (e.g., a saline source) coupled to the handle may provide fluid (e.g., saline) to be delivered through the electrode to the tissue and/or the target site. The fluid may be delivered at a constant rate, a pulsed rate, a user-controlled rate, etc. In these aspects, one or more of the energy delivery and/or the fluid delivery may be controlled by one or more actuators (e.g., triggers, buttons, touch screens, foot pedals, etc.). 
     The medical devices and methods discussed above allow a user to treat tissue by delivering electrical energy into the tissue, and delivering fluid, either simultaneously or sequentially. For example, a user may couple an electrode to the distal end and deliver the distal end to an interior lumen of a subject to deliver medical therapy in a portion of a procedure (e.g., mark, cauterize, or resect tissue). The insulation tip may help to prevent or minimize damage and/or unintended contact between the electrode and the tissue. The user may also deliver fluid distally out of the distal end of the electrode, either simultaneously or sequentially with the energy delivered, which may help the user to more quickly and efficiently deliver the medical therapy, for example, cut, dissect, ablate, mark, coagulate, cauterize, or otherwise treat tissue. Moreover, the user may deliver fluid and energy without removing the medical device from the patient or subject, which may help to reduce the costs and duration of the procedure, also potentially reducing the risks to the subject. 
     While principles of the present disclosure are described herein with reference to illustrative aspects for particular applications, it should be understood that the disclosure is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, aspects, and substitution of equivalents all fall within the scope of the aspects described herein. Accordingly, the disclosure is not to be considered as limited by the foregoing description.