Abstract:
An electrosurgical suction coagulator is disclosed having improved thermal insulation between the active electrode and adjacent tissue. In embodiments, passive insulation is used to control the transfer of thermal energy from an electrosurgical electrode into surrounding tissue. Braided, closed-sell foam material, and open cell foam materials may be used to thermally insulate the outer surface of a suction coagulator shaft from an inner electrode. In embodiments, a suction coagulator shaft includes an external covering formed from open-cell foam material, which may be saturated with a coolant, such as water or saline, to increase the thermal mass of the shaft. In other embodiments, active cooling delivers coolant to the operative site. In yet other embodiments, a suction coagulator shaft includes a cooling jacket through which coolant is passed to actively cool the instrument. The improved electrosurgical suction coagulator disclosed herein may have a reduced operating surface temperatures which may result in reduced risk of undesirable effects to adjacent tissue, and may result in reduced operative times and improved patient outcomes.

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates generally to electrosurgical coagulators and, more particularly, to an electrosurgical suction coagulator having improved thermal insulation between the active electrode and adjacent tissue. 
     2. Background of Related Art 
     The coagulation of bleeding blood vessels and tissue using electrically conductive suction tubes is a technique which has been widely used for some time. Typically, a combination electrosurgery and suction device is employed in surgery wherever excessive blood must be removed from the bleeding site in order to facilitate hemostasis of any bleeding vessels. More particularly, during any given surgical procedure, several layers of tissue usually must be penetrated to reach the operative field. When resecting an organ, for example, a gallbladder, the tissue surrounding the organ must be penetrated and dissected before the organ can be removed. The tissues being dissected, however, often contain blood vessels, nerves, lymph vessels, and the like, which should not be severed. The technique of blunt dissection is often used to prevent unnecessary damage caused by severing these vessels or nerves. 
     Blunt dissection, as opposed to sharp dissection, involves the use of a blunt surface to break through the tissue, thereby preventing the damage and bleeding caused by lasers and scalpels, the tools of sharp dissection. Hard surgical sponges, generally known as peanuts or Kittner sponges, or a surgeon&#39;s fingers are often used as blunt dissectors. A peanut is a tightly wound ball of absorbent material, such as gauze or other woven cotton, which is typically gripped with forceps and acts to abrade the tissue being dissected so that the dissection can be performed by either pulling on the tissue or by forcing the peanut through the tissue. 
     Laparoscopy, surgery performed through several small incisions made in the body rather than through a single large opening, has become the preferred method of performing certain procedures due to the reduced trauma and risk of infection as compared to normal, open surgical procedures. As a result, the use of conventional blunt dissectors, such as the peanut, during laparoscopic procedures presents many significant drawbacks. For instance, peanuts, being secured only by forceps, can become loose in the body. Further, the view of the operative field often becomes obstructed by pieces of tissue, blood and other bodily fluids produced during blunt dissection, necessitating the immediate need for both irrigation and aspiration of the operative field. Since it is undesirable to create additional incisions, the dissection must be stopped, the dissector must be removed, and all irrigator and/or aspirator must be inserted to remove the fluid and debris. 
     The use of electrical energy including radiofrequency and microwave energy and, in particular, radiofrequency (“RF”) electrodes or microwave antennae for ablation of tissue in the body or for the treatment of pain is known. For example, electrosurgery is a technique of using alternating current electrical signals in the approximately 200 kHz-3.3 mHz range that are generated by a source of electrosurgical energy, such as an electrosurgical generator, in connection with surgical instruments, to cut or coagulate biologic tissue endogenically. This electrosurgical signal can be a sinusoidal waveform operating in a continuous mode at a 100% duty cycle, or pulse modulated at a duty cycle of less than 100%. Typically, electrosurgical signals are operated at 100% duty cycle for maximal cutting effect, and are pulse modulated at duty cycles ranging from 50% to 25% for less aggressive cutting, or, at a substantially lower duty cycle of approximately 6%, for coagulating. The electrosurgical carrier signal may also be varied in intensity. The electrosurgical signal is applied to the patient via electrodes in either monopolar mode, or bipolar mode. In monopolar mode, the active electrode is the surgical instrument at the surgical site, and the return electrode is elsewhere on the patient, such that the electrosurgical signal passes through the patient&#39;s body from the surgical site to the return electrode. In bipolar mode, both the active and return electrodes are at the surgical site, such as with an instrument having an array of electrodes, so that the electrosurgical signal passes only through the tissue situated between the RF electrodes of the instrument. 
     Electrosurgical suction coagulators which both coagulate and dissect tissue have also been available for some time. Generally, these devices include a shaft formed from a conductive suction tube electrode having an electrically insulating coating over all but a most distal portion of the tube, so that the distal portion forms a generally annular ablating electrode. The shaft may be formed of malleable materials to enable a surgeon to bend the shaft to a desired shape. The distal end can be used as a blunt dissection device and/or a blunt coagulator. A suction source is attached to a proximal portion of the tube for evacuating excess fluid and debris from the surgical site through the distal end of the tube. The electrode is operably coupled to a source of electrosurgical energy, such as an electrosurgical generator. 
     The described electrosurgical suction coagulators may have drawbacks. In particular, heat conducted from the suction tube electrode to the outer surface of the shaft may cause the surface of the shaft to reach temperatures of 60° C. or greater. This may be a concern during surgical procedures, such as an electrosurgical adenotonsillectomy, where the shaft of a suction coagulator may be in proximity to, or in contact with, anatomical structures unrelated to the procedure, such as the uvula or the oral commissure. The elevated shaft temperature may have undesirable effects on such unrelated anatomical structures, including uvular edema and erythema of the oral commissure area. An electrosurgical suction coagulator which avoids or minimizes such undesirable effects would be a welcome advance in the art, particularly when such benefits are realized in a rugged, reliable, and relatively simple design. 
     SUMMARY 
     The present disclosure provides an electrosurgical suction coagulation system having, and related methods for, improved control of the shaft surface temperature. In particular, embodiments in accordance with the present disclosure may provide passive thermal insulation of the shaft, active cooling of the shaft, and may advantageously include combinations of passive insulation and active cooling, as will be described hereinbelow. 
     In an embodiment in accordance with the present disclosure, an electrosurgical suction coagulator includes a shaft formed from a conductive suction tube, an outer dielectric sheath covering over all but a distal electrode portion of the tube, and has disposed therebetween an insulating layer formed from braided material having low thermal conduction, for example, braided polymeric or ceramic fibers. The braided material may be configured as a tubular braided sheath or a spiral wrapped layer. The combination of air voids in the braided layer and the low thermal conductive properties of the braided insulating material may reduce thermal conduction from the metallic suction tube to the exterior surface of the instrument. In envisioned embodiments, an insulating layer may be formed from woven material. 
     In embodiments, the shaft of a suction coagulator in accordance with the present disclosure may be straight or contoured. The shaft may additionally be formed from malleable materials to enable a user, for example, a surgeon or clinician, to bend the shaft to a desired shape. A suction coagulator in accordance with the present disclosure may include a handle. The handle may include at least one control for activating the electrosurgical energy and/or evacuation (i.e., suction). 
     In envisioned embodiments, a suction coagulator includes thermal isolation between a suction tube and a distal electrode tip, formed from, for example without limitation, ceramic insulating material and/or polymeric insulating material. The tip may be operably coupled to the suction tube by at least one electrically conductive element, such as a wire. Additionally or alternatively, a distal electrode tip may be operably coupled to a source of electrosurgical energy by at least one of a wire and the suction tube. 
     In another envisioned embodiment, an insulating layer disposed between the tubular electrode and dielectric sheath is formed from closed-cell foam material, for example, closed cell foamed polyurethane. Additionally or alternatively, the outer surface of the dielectric sheath may include a closed cell foam covering disposed thereupon, which may further reduce thermal conduction from the electrode to adjacent tissue. 
     In embodiments, the outer surface of the dielectric sheath may include an open cell foam covering disposed thereupon. During use, the open foam layer may be infused with a fluid, for example, water or saline solution, which may increase the thermal mass of the covering and provide a cooling effect, thereby reducing surface temperature of the instrument shaft. 
     In embodiments, an electrosurgical generator in accordance with the present disclosure may be configured to limit the activation time of a suction coagulator, and/or enforce minimum quiescent times between activations. During use, the electrosurgical generator may determine whether the activation time has exceeded a threshold, and in response thereto, deactivate the generator. Additionally, reactivation of the generator may be inhibited until the expiration of a “rest” time period, or until a user input is received by the generator. 
     The instrument may be configured to provide instrument identification information to the generator, for example, an optical code (i.e., barcode), an RFID tag, or other suitable machine- or human-readable encodings. The generator may use such instrument identification information to determine corresponding activation and quiescent time parameters for the instrument. 
     In an envisioned embodiment, a suction coagulator in accordance with the present disclosure includes a sensor that is adapted to sense the surface temperature of the instrument. The sensor may be operably coupled to an electrosurgical generator. The electrosurgical generator may be configured to respond to the sensed temperature, by, for example, limiting the activation time, altering the electrosurgical signal, and/or deactivating the generation of the electrosurgical signal. In embodiments, the generator may additionally or alternatively respond to at least one parameter related to the sensed temperature of the instrument, for example, a change in temperature of the instrument and/or a rate of change of temperature of the instrument. 
     In embodiments, an electrosurgical generator in accordance with the present disclosure may be configured to issue a prompt (e.g., an alarm) to the user. A prompt may be issued to advise the user to pause the activation of the instrument. In envisioned embodiments, a prompt may be issued to advise the user to replenish depleted fluids in, for example, a fluid-infused open foam cover. Such a prompt may be based upon, for example, cumulative activation time, instrument identity, and/or the surface temperature of the instrument. The alarm may be automatically cleared after a predetermined time period. Additionally or alternatively, the alarm may be cleared by a user input received by the electrosurgical generator. 
     Other embodiments according to the present disclosure are envisioned wherein an electrosurgical suction coagulator includes a conduit for introducing a coolant, for example, saline solution, to the distal tip of the instrument during use. The conduit may be configured to “drip” coolant onto an electrode disposed at the distal end of the instrument. The conduit may be in fluid communication, preferably at the proximal end of the instrument, to a source of cooling fluid, for example, a saline bag, that may provide cooling fluid via any suitable manner of delivery, for example, by gravity feed, pump, or pressurized vessel. 
     In other envisioned embodiments, en electrosurgical suction coagulator according the present disclosure includes a coolant jacket that may be formed by a conduit included in the instrument. Coolant is introduced into the coolant jacket, preferably at the proximal end of the instrument, flows through the conduit towards the distal tip region of the instrument, and exits the instrument. The coolant jacket may be configured to cool the tip and/or the surface of the instrument. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is an oblique view of an exemplary embodiment of an electrosurgical suction coagulator system in accordance with the present disclosure; 
         FIG. 2A  is a side cutaway view of an exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having a braided insulation region; 
         FIG. 2B  is a section view of the electrosurgical suction coagulator of  FIG. 2A ; 
         FIG. 3A  is a side cutaway view of another exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having a closed cell foam insulation region; 
         FIG. 3B  is a section view of the electrosurgical suction coagulator of  FIG. 3A ; 
         FIG. 4A  is a side cutaway view of yet another exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having an inner closed cell foam insulation region and an outer closed cell foam insulation region; 
         FIG. 4B  is a section view of the electrosurgical suction coagulator of  FIG. 4A ; 
         FIG. 5A  is a side cutaway view of still another exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having an outer closed cell foam insulation region; 
         FIG. 5B  is a section view of the electrosurgical suction coagulator of  FIG. 5A ; 
         FIG. 6A  is a side cutaway view of another exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having an outer open cell foam insulation region; 
         FIG. 6B  is a section view of the electrosurgical suction coagulator of  FIG. 6A ; 
         FIG. 7A  is a side cutaway view of another exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having a lumen to deliver coolant to the distal end thereof; 
         FIG. 7B  is a section view of the electrosurgical suction coagulator of  FIG. 7A ; 
         FIG. 8A  is a side cutaway view of an exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having a spiral coolant jacket; 
         FIG. 8B  is an oblique view of the exemplary electrosurgical suction coagulator of  FIG. 8A ; 
         FIG. 9A  is a side cutaway view of an exemplary embodiment of an electrosurgical suction coagulator in accordance with the present disclosure having a cylindrical coolant jacket; and 
         FIG. 9B  is a section view of the electrosurgical suction coagulator of  FIG. 9A . 
     
    
    
     DETAILED DESCRIPTION 
     Particular embodiments of the present disclosure will be described herein with reference to the accompanying drawings. As shown in the drawings and as described throughout the following description, and as is traditional when referring to relative positioning on an object, the term “proximal” refers to the end of the apparatus that is closer to the user and the term “distal” refers to the end of the apparatus that is further from the user. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. 
     With reference to  FIG. 1 , an electrosurgical suction coagulator system  100  is presented having a suction coagulator  110  that is operably coupled to an electrosurgical generator  140  via a conductor  145 . Suction coagulator  110  is operably coupled to a vacuum source  150  by a lumen  155 . Suction coagulator  110  includes a handle  115  disposed at the proximal end thereof and a elongated shaft  120  extending distally from the handle  115 . The shaft  120  may be formed from material having malleable or flexible properties, for example without limitation, metallic material such as aluminum and alloys thereof and/or polymeric materials such as polyurethane (PU) or polyvinyl chloride (PVC). A shaft  120  thus formed may be bent to a desired shape by the user, as shown by way of example by bent shaft  120 ′. 
     Distal end  124  of shaft  120  includes an exposed tubular electrode  125  for delivering electrosurgical energy to tissue, the electrode  125  having a conduit  126  defined longitudinally therethrough for providing suction to a surgical site. Conduit  126  is in fluid communication with vacuum source  150  via lumen  155 . 
     In an embodiment, handle  115  may include a control  130  which may be a handswitch for controlling the application of electrosurgical energy, i.e., activation and deactivation of an electrosurgical signal. Handle  115  may include an additional or second control  131  for controlling the application of suction to the surgical site. In embodiments, control  131  may be operably coupled to a valve (not shown) that may be disposed within handle  115 , shaft  120 , vacuum source  150 , and/or lumen  155 . In other envisioned embodiments, control  131  may be operably coupled to a regulator, motor control, or other suitable manner of vacuum control. 
     Turning now to  FIGS. 2A and 2B , a suction coagulator  200  in accordance with the present disclosure includes a housing  215  disposed proximally to an elongated shaft  220 . Housing  215  may be a handle. Shaft  220  includes an insulating sheath  226  formed from any suitable dielectric material, for example, polymeric materials such as PU, PVC and the like. Shaft  220  includes a conductive tube  224  disposed coaxially within insulating sheath  226  and having a tubular distal tip electrode  225  protruding distally from insulating sheath  226  to form at least one aspiration port  265 . Conductive tube  224  may be formed from any suitable electrically conductive material, including without limitation, aluminum or stainless steel. An insulator  270  having a generally cylindrical shape is disposed between conductive tube  224  and insulating sheath  226 . Insulator  270  may be formed from any suitable heat-insulating material, for example without limitation, high-temperature polymers, ceramic fiber, or mineral fiber. Insulator  270  may be constructed from braided, woven, spun-woven, or randomly dispersed materials. An isolator  260  is disposed between distal tip electrode  225  and conductive tube  224  to thermally insulate the distal tip electrode  225  from the conductive tube  224  and to position distal tip electrode  225  coaxially with the distal end of insulating sheath  226 . Distal tip electrode  225  and conductive tube  224  are operably connected by a conductive element  227 , which may be a wire or a strap, to facilitate the delivery of electrosurgical energy to a surgical site (not shown) by distal tip electrode  225 . In an embodiment, isolator  260  may be formed of heat-resistant material, for example, ceramic material. In other envisioned embodiments, isolator  260  is integrally formed with sheath  226 . In use, insulator  270  acts to insulate the outer surface of sheath  226  from thermal energy that may propagate from, for example, the surgical site (not explicitly shown), distal tip electrode  225 , and/or conductive tube  224 . Vacuum source  250  may be selectively activated to provide aspiration suction to tube  224  and tip  225  to facilitate the removal of biodebris from the surgical site (not explicitly shown). 
     In another envisioned embodiment best illustrated in  FIGS. 3A and 3B , a suction coagulator  300  includes an elongated shaft  320  supported by a housing  315 , the shaft  320  further including an insulator  370  having a generally cylindrical shape that is longitudinally disposed between a conductive tube  324  and a dielectric sheath  326 . Insulator  370  may be formed from a closed cell foam material, for example without limitation, closed cell polyurethane foam. A tubular distal tip electrode  325  extends from the distal end of shaft  320  to form at least one aspiration port  365 . An isolator  360  is disposed between distal tip electrode  325  and conductive tube  324  to thermally insulate the distal tip electrode  325  from the conductive tube  324  and additionally to position distal tip electrode  325  coaxially with the distal end of dielectric sheath  326 . Distal tip electrode  325  and conductive tube  324  are operably coupled by a conductive element  327 , which may be a wire or a strap. In an embodiment, isolator  360  may be formed of heat-resistant material, for example, ceramic. In other envisioned embodiments, seal  360  may be integrally formed with sheath  326 . 
     In yet another envisioned embodiment best illustrated in  FIGS. 4A and 4B , a suction coagulator  400  includes an elongated shaft  420  that is supported by a housing  415 . The shaft  420  includes an insulator  470  having a generally cylindrical shape that is longitudinally disposed between a conductive tube  424  and a dielectric sheath  426 , and an insulator  480  having a generally cylindrical shape that is longitudinally disposed around dielectric sheath  426 . A tubular distal tip electrode  425  extends from the distal end of shaft  420  to form at least one aspiration port  465 . Insulators  470 ,  480  may be formed from a closed cell foam material, for example without limitation, closed cell polyurethane foam. In use, insulators  470 ,  480  act to insulate the outer surface of shaft  420  from thermal energy that may propagate from, for example, the surgical site, distal tip electrode  425 , and/or conductive tube  424 . An isolator  460  is disposed between distal tip electrode  425  and conductive tube  424  to thermally insulate the distal tip electrode  425  from the conductive tube  424  and additionally to position distal tip electrode  425  coaxially with the distal end of dielectric sheath  426 . Distal tip electrode  425  and electrode  424  are operably coupled by a conductive element  427 , which may be a wire or a strap. Insulator  480  may include at the distal end thereof an annular insulating region  481  that encloses the distal end  425  of dielectric sheath  426  and/or isolator  460 . In embodiments, annular insulating region  481  may be joined to electrode  425  by a bonded region  482 , for example, by adhesive, heat weld, or crimp. 
     Turning to  FIGS. 5A and 5B , yet another embodiment according to the present disclosure is illustrated wherein a suction coagulator  500  includes an elongated shaft  520  that is supported by a housing  515 . The shaft  520  further including a tubular electrode  524  having generally cylindrical sheath  526  longitudinally disposed around the outer surface thereof. An insulator  580  is concentrically disposed around sheath  526 . Insulator  580  may be formed from a closed cell foam material, for example without limitation, closed cell polyurethane foam. In use, insulator  580  acts to reduce the propagation of thermal energy from, for example, the surgical site, an electrode tip  525 , and/or electrode  524 , to the outer surface of shaft  520 . 
     In  FIGS. 6A and 6B  there is illustrated an envisioned embodiment of a suction coagulator  600  in accordance with the present disclosure wherein an elongated longitudinal shaft  620  is supported by a housing  615 . An open cell foam cover  680  surrounds shaft  620 . The shaft  620  includes a tubular electrosurgical electrode  624  disposed longitudinally therethrough, the tubular electrosurgical electrode  624  having an exposed tip  625  for delivering electrosurgical energy to tissue. A generally cylindrical sheath  626  is longitudinally disposed around substantially all but the exposed tip  625  of tubular electrosurgical electrode  624 . Electrode  624  is in fluid communication with the source of vacuum  250  for the aspiration of biodebris, for example, tissue, eschar, blood and/or other bodily fluids. During use, the open cell foam cover may be infused with a fluid (not explicitly shown) for example, water or saline solution. The fluid may increase the thermal mass of the covering and, additionally or alternatively, may provide a cooling effect. In this manner, an increase in surface temperature of the instrument shaft may be diminished or precluded, thereby reducing the risk of undesirable effects on adjacent anatomical structures. 
     In  FIGS. 7A and 7B , there is shown an envisioned embodiment wherein a suction coagulator  700  includes an elongated shaft  720  that is supported by a housing  715 . The shaft  720  includes a tubular electrosurgical electrode  724  disposed longitudinally therethrough, the tubular electrosurgical electrode  724  having an exposed tip  725  for delivering electrosurgical energy to tissue. A generally cylindrical sheath  726  is longitudinally disposed around substantially all but the exposed tip  725  of tubular electrosurgical electrode  724 . At least one cooling lumen  770  is disposed longitudinally on the shaft  720  for delivering coolant C to the distal region, i.e., electrode  725  of suction coagulator  700 . Cooling lumen  770  is in fluid communication with a reservoir  790  via a conduit  795 . In embodiments, a connector  796  is provided for coupling a conduit  795  to cooling lumen  770 . Reservoir  790  may contain a coolant, for example without limitation, saline or water. In use, coolant C may flow from reservoir  790  through conduit  795 , lumen  770 , and discharge from distal end  772  of lumen  770 . A valve (not explicitly shown) may be provided to regulate the flow of coolant. The valve (not explicitly shown) may be caused to be actuated by a user and/or by an automated controller, such as a processor. Coolant C may flow from reservoir  790  via gravity feed (i.e., “drip” feed) and/or by pressure feed provided by, for example without limitation, a centrifugal pump, a positive displacement pump, or a peristaltic pump (not explicitly shown). 
     Turning now to  FIGS. 8A and 8B , another envisioned embodiment of a suction coagulator  800  in accordance with the present disclosure is illustrated wherein a proximal housing  815  supports an elongated shaft  820  extending distally therefrom. A generally tubular cover  826  is longitudinally disposed around substantially all but an exposed tip  825  of a tubular electrosurgical electrode  824  that is disposed longitudinally through shaft  820 . A region  871  between cover  826  and electrode  824  defines a cooling jacket  872  that surrounds the tubular electrode  824 . As best shown in  FIGS. 8A and 8B , a cooling jacket  872  may include a cooling lumen  873  having a generally helical shape, and having an inlet port  870  and an outlet port  875 . The helical coils formed by cooling lumen  873  may form an open helix, wherein the helix pitch is greater than the outer diameter of the cooling lumen  873 , or a closed helix wherein the helix pitch is substantially equal to the outer diameter of the cooling lumen  873 . Inlet port  870  is in fluid communication with a coolant source  790  via a conduit  795 . Coolant C may be any biocompatible fluid, for example without limitation, saline, water, or air. Coolant C may flow from coolant source  790  via gravity feed (i.e., “drip” feed) and/or by pressure feed provided by, for example, a pump, as previously described herein. In one embodiment, coolant flows distally though the helical cooling lumen  873  until the distal end  878  of jacket  872  is reached. Coolant C then flows proximally through a return lumen  874  to outlet port  875 , whereupon the coolant exits the suction coagulator  800 . In another embodiment, coolant C flow may be reversed from that described hereinabove, i.e., coolant may flow initially to distal end  878  and thereafter proceed proximally through helical cooling lumen  873 , and subsequently, discharged from the suction coagulator  800  at outlet port  875 . In this manner, a cooling effect can be selectively biased towards a proximal end of the shaft or a distal end of the shaft as desired. For example, in use during an electrosurgical procedure such as an adenotonsillectomy, coolant C may be caused flow distally wherein fresh coolant is introduced to cooling jacket  872  at the proximal end thereof. Thus a cooling effect may be biased toward a proximal end  830  of shaft  820 , which may be adjacent to, for example, anatomical structures unrelated to the electrosurgical procedure, such as the uvula and the oral commissure area, thereby reducing the risk of undesired effects to such areas. Alternatively, cooling may be biased towards a distal end  831  of shaft  820  by causing coolant to flow proximally by introducing coolant C to cooling jacket  872  at the distal end thereof. In embodiments, the direction of coolant C flow may be selected by causing a reversing valve (not explicitly shown) that is in fluid communication with cooling jacket  872  to be actuated in a manner consistent with the desired direction of coolant C flow. 
       FIGS. 9A and 9B  illustrate still another envisioned embodiment of a suction coagulator  900  in accordance with the present disclosure is illustrated, the suction coagulator including a distal housing  915  having extending distally therefrom an elongated shaft  920 . Shaft  920  includes a cooling jacket  972  that is formed by the generally cylindrical region longitudinally disposed between a tubular electrode  924  and a tubular cover  926 . The cooling jacket is sealed at the distal end thereof by distal seal  960  and at the proximal end thereof by proximal seal  961 . A cooling supply lumen  970  is in fluid communication with the cooling jacket via an inlet port  962  provided by proximal seal  961 . During use, coolant C is admitted into cooling jacket  972  at the proximal end thereof, and thereafter flows distally. A distal return opening  963  is provided by cover  926 , or additionally or alternatively, by distal seal  960 . Supply end  870  is in fluid communication with a coolant source  790  via a conduit  795 . Coolant C may be any biocompatible fluid, for example without limitation, saline, water, or air. Coolant C may flow to cooling jacket  972  via conduits  970 ,  995  from coolant source  990  via gravity feed (i.e., “drip” feed) and/or by pressure feed provided by, for example, a pump, as previously described herein. In one embodiment, coolant C flows distally though the cooling jacket  972  until the distal end  978  of jacket  972  is reached. Coolant C then flows through distal return opening  963 , proximally through a return lumen  974  to outlet port  975 , whereupon the coolant exits the suction coagulator  900 . In another embodiment, coolant C flow may be reversed from that described hereinabove, i.e., coolant C may flow initially to distal end  978  and thereafter proceed proximally through cooling jacket  972 , and subsequently, discharged from the suction coagulator  900  at outlet port  975 . The direction of coolant flow may be selectively reversed as previously described herein. 
     The described embodiments of the present disclosure are intended to be illustrative rather than restrictive, and are not intended to represent every embodiment of the present disclosure. Further variations of the above-disclosed embodiments and other features and functions, or alternatives thereof, may be made or desirably combined into many other different systems or applications without departing from the spirit or scope of the disclosure as set forth in the following claims both literally and in equivalents recognized in law.