Abstract:
A method of manufacturing an electrosurgical tool includes the initial step of coupling a proximal end of a substantially malleable elongate tube-like shaft to a distal end of a housing. A tub-like dielectric sheath is disposed on the tube-like shaft. The method also includes the steps of coupling a tube-like electrode having a first thermal conductivity K 1  coaxially through the tube-like dielectric sheath and coupling a proximal end of the tube-like electrode to a source of suction to provide fluid communication between the tube-like electrode and the source of suction. The method also includes the steps of electrically connecting the tube-like electrode to a source of energy and coupling a thermally conductive member to the tube-like shaft. The thermally conductive member has a second thermal conductivity K 2  that is less than K 1  and is configured to impede the propagation of thermal energy proximally.

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. 
     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. 
     SUMMARY 
     According to an embodiment of the present disclosure, a method of manufacturing an electrosurgical tool includes the initial step of coupling a proximal end of a substantially malleable elongate tube-like shaft to a distal end of a housing. A tub-like dielectric sheath is disposed on the tube-like shaft. The method also includes the steps of coupling a tube-like electrode having a first thermal conductivity K 1  coaxially through the tube-like dielectric sheath and coupling a proximal end of the tube-like electrode to a source of suction to provide fluid communication between the tube-like electrode and the source of suction. The method also includes the steps of electrically connecting the tube-like electrode to a source of energy to provide energy to tissue via the exposed distal end of the tube-like electrode and coupling a thermally conductive member to the tube-like shaft. The thermally conductive member has a second thermal conductivity K 2  that is less than K 1  and is configured to impede the propagation of thermal energy proximally. 
    
    
     
       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 embodiment of an electrosurgical suction coagulator system in accordance with the present disclosure; 
         FIG. 2A  is a side cutaway view of an embodiment of an electrosurgical suction coagulator in accordance with the present disclosure; 
         FIG. 2B  is a section view of the electrosurgical suction coagulator of  FIG. 2A ; 
         FIG. 3A  is a side cutaway view of another embodiment of an electrosurgical suction coagulator in accordance with the present disclosure; 
         FIG. 3B  is a section view of the electrosurgical suction coagulator of  FIG. 3A ; 
         FIG. 4  is oblique view of another embodiment an electrosurgical suction coagulator system in accordance with the present disclosure; 
         FIG. 5A  is a side cutaway view of an embodiment of an electrosurgical suction coagulator in accordance with the present disclosure; 
         FIG. 5B  is a side cutaway view of a component of the electrosurgical coagulator of  FIG. 5A  in accordance with another embodiment of the present disclosure; 
         FIG. 5C  is a side cutaway view of a component of the electrosurgical coagulator of  FIG. 5A  in accordance with another embodiment of the present disclosure; 
         FIG. 6A  is a side cutaway view of an embodiment of an electrosurgical suction coagulator in accordance with the present disclosure; 
         FIG. 6B  is a side cutaway view of a component of the electrosurgical coagulator of  FIG. 6A  in accordance with another embodiment of the present disclosure; and 
         FIG. 6C  is a side cutaway view of a component of the electrosurgical coagulator of  FIG. 6A  in accordance with another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Particular embodiments of the present disclosure are 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 a proximal end thereof and an elongated shaft  120  extending distally from the handle  115 . Shaft  120  includes an insulating sheath  126  disposed at least partially thereon. Insulating sheath  126  is formed from any suitable dielectric material, for example, polymeric materials such as PU, PVC, and the like. 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. 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 ′ (shown in phantom). 
     Shaft  120  includes a tube-like electrode  125  for delivering electrosurgical energy to tissue. The electrode  125  is disposed coaxially through shaft  120  and is exposed at a distal end  124  of shaft  120  to form an aspiration port  128  defined therethrough. Tube-like electrode  125  defines a conduit (not explicitly shown) longitudinally through shaft  120  to provide suction to a surgical site. By way of the conduit, the aspiration port  128  is in fluid communication with vacuum source  150  via lumen  155 . The outer diameter of tube-like electrode  125  is sized similarly to the inner diameter of shaft  120  to form a press or interference-fit between electrode  125  and shaft  120 . In use, insulating sheath  126  is configured to provide electrical insulation between electrode  125  and the surface of shaft  120 . 
     Disposed concentrically about shaft  120  and proximal to the distal end  124  thereof is a thermally conductive member  122 . The diameter of shaft  120  is accordingly sized similarly to the inner diameter of member  122  to form a press or interface-fit between member  122  and shaft  120 . Alternatively or additionally, member  122  may be coupled to shaft  120  by any suitable coupling technique such as, for example, crimping, welding, soldering, adhesive, etc. During a surgical procedure, member  122  is positioned relative to shaft  120  so as to sufficiently impede the propagation of thermal energy proximally and/or away from the surgical site and/or the distal end  124  of shaft  120 . To sufficiently impede proximal propagation of thermal energy, member  122  is formed of a material less thermally conductive than that of shaft  120 . More specifically, tube-like electrode  125  has a first thermal conductivity K 1  and member  122  has a second thermal conductivity K 2  that is less than the thermal conductivity K 1  of tube-like electrode  125 . For example, member  122  may be formed from a suitable thermally conductive material such as, without limitation, stainless steel, steel, polyvinyl chloride (PVC), thermoplastic polymer, etc. To electrically insulate member  122 , a suitable insulating material (e.g., an insulative coating, a heat-shrink insulator, etc.) may be applied to at least a portion of the surface of member  122 . Additionally or alternatively, at least a portion of member  122  may be made from a suitable non-conductive material. 
     In an embodiment, handle  115  includes a control  130  (e.g., handswitch) for controlling the application of electrosurgical energy, i.e., activation and deactivation of an electrosurgical signal. Handle  115  includes 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 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 is operably coupled to an electrosurgical generator  240  via a conductor  245  and 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. 
     A tube-like electrode  225  for delivering electrosurgical energy to tissue is disposed coaxially though shaft  220  and is exposed at a distal end  224  of shaft to form an aspiration port  228  defined therethrough. Tube-like electrode  225  defines a conduit  230  longitudinally through shaft  220  to provide suction to a surgical site. Conduit  230  is in fluid communication with vacuum source  250  via lumen  255 . Tube-like electrode  224  may be formed from any suitable electrically conductive material, including without limitation, aluminum or stainless steel. 
     A thermally conductive member  222  is disposed concentrically about shaft  220  and proximal to the distal end  224  thereof. In embodiments, thermally conductive member  222  is disposed between about 0.15 inches and about 0.25 inches from the distal end  224  of shaft  220  or disposed a suitable longitudinal distance from distal end  224  of shaft  220  such that during use of suction coagulator  220  member  222  is positioned relative to shaft  220  to efficiently impede the propagation of thermal energy proximally and/or away from the surgical site, the exposed tip of electrode  225 , and/or the distal end  224  of shaft  220 . In embodiments, member  222  may be between about 0.1 inches and about 0.5 inches in longitudinal length or a longitudinal length sufficient to impede the propagation of thermal energy proximally. 
     Turning now to  FIGS. 3A and 3B , a suction coagulator  300  in accordance with another embodiment the present disclosure is operably coupled to an electrosurgical generator  340  via a conductor  345  and includes a housing  315  disposed proximally to an elongated shaft  320 . Shaft  320  includes an insulating sheath  326  formed from any suitable dielectric material. 
     A tube-like electrode  325  for delivering electrosurgical energy to tissue is disposed coaxially though shaft  320  and is exposed at a distal end  324  of shaft to form an aspiration port  328  defined therethrough. Tube-like electrode  325  defines a conduit  330  longitudinally through shaft  320  to provide suction to a surgical site. Conduit  330  is in fluid communication with a vacuum source  350  via a lumen  355 . Tube-like electrode  325  may be formed from any suitable electrically conductive material, including without limitation, aluminum or stainless steel. 
     Shaft  320  includes a recess  321  formed concentrically therein and proximal to the distal end  324  thereof. A thermally conductive member  322  is disposed concentrically within the recess  321  (e.g., via welding, adhesive, etc.), such that an outer surface  322   a  of thermally conductive member  322  is substantially coplanar with an outer surface  320   a  of shaft  320  and the insulating sheath  326  is disposed between thermally conductive member  322  and tube-like electrode  325 . In this scenario, the diameter of shaft  320  is substantially uniform along at least a majority along the length thereof. 
     In embodiments, recess  321  is disposed between about 0.15 inches and about 0.25 inches from the distal end  324  of shaft  320  or disposed a suitable distance from distal end  324  of shaft  320  such that during use of suction coagulator  300 , member  322  is positioned relative to shaft  320  to efficiently impede the propagation of thermal energy proximally and/or away from the surgical site and/or the distal end  324  of shaft  320 . In embodiments, member  322  may be between about 0.1 inches and about 0.5 inches in longitudinal length or a longitudinal length sufficient to impede the propagation of thermal energy proximally. The longitudinal length of recess  321  may be varied in accordance with the longitudinal length of member  322  to receive member  322  therein. 
       FIG. 4  illustrates another embodiment of the presently disclosed electrosurgical coagulator system shown generally as  400 . Electrosurgical coagulator system  400  is substantially as described above with respect to system  100  but includes additional features which are discussed in detail below. As with system  100 , system  400  includes a suction coagulator  410  operably coupled to an electrosurgical generator  440  via a conductor  445  and to a vacuum source  450  by a lumen  455 . Suction coagulator  410  includes a handle  415  disposed at a proximal end thereof and an elongated shaft  420  extending distally from the handle  415 . Shaft  420  includes an insulating sheath  426  disposed at least partially thereon. Insulating sheath  426  is formed from any suitable dielectric material, for example, polymeric materials such as PU, PVC, and the like. The shaft  420  may be formed from material having malleable or flexible properties, for example without limitation, metallic material such as aluminum and alloys thereof. A shaft  420  thus formed may be bent to a desired shape by the user, as shown by way of example by bent shaft  420 ′ (shown in phantom). 
     Shaft  420  includes a tube-like electrode  425  for delivering electrosurgical energy to tissue. The electrode  425  is disposed coaxially through shaft  420  and defines a conduit (not explicitly shown) longitudinally through shaft  420  to provide suction to a surgical site. An electrically conductive distal tip  422  is mechanically coupled to a distal end of the tube-like electrode  425  such that the distal tip  422  is exposed at a distal end  424  of shaft  420  to form an aspiration port  428  defined therethrough. The distal tip  422  is in electrical communication with tube-like electrode  425  to deliver electrosurgical energy to tissue during a surgical procedure. In embodiments, tube-like electrode  425  may be at least partially exposed at the distal end  425  of shaft  420 . By way of the conduit (not explicitly shown), the aspiration port  428  is in fluid communication with vacuum source  450  via lumen  455 . The outer diameter of tube-like electrode  425  is sized similarly to the inner diameter of shaft  420  to form a press or interference-fit between electrode  425  and shaft  420 . In use, insulating sheath  426  is configured to provide electrical insulation between electrode  425  and the surface of shaft  420 . 
     The inner diameter of the distal tip  422  is sized similarly to the outer diameter of tube-like electrode  425  to form a fit (e.g., threaded-fit, press-fit, interface-fit, etc.) between distal tip  422  and tube-like electrode  425 . Additionally or alternatively, distal tip  422  may be mechanically coupled to the distal end of tube-like electrode  425  by any suitable coupling technique or combination of coupling techniques such as, for example, crimping, welding, soldering, adhesive, or any combination thereof. 
     To sufficiently impede proximal propagation of thermal energy, the distal tip  422  is formed of a material less thermally conductive than that of the shaft  420 . For example, distal tip  422  may be formed from a suitable thermally conductive material such as, without limitation, stainless steel, steel alloy, lead, aluminum alloy, etc. In this manner, the distal tip  422  operates to sufficiently impede the propagation of thermal energy proximally and/or away from the surgical site and/or the distal end  424  of the shaft  420  during a surgical procedure. 
     Referring now to  FIGS. 5A ,  5 B, and  5 C, another embodiment of the suction coagulator  410  of  FIG. 4  is shown generally as  500 . The suction coagulator  500  is operably coupled to an electrosurgical generator  540  via a conductor  545  and includes a housing  515  disposed proximally to an elongated shaft  520 . Shaft  520  includes an insulating sheath  526  formed from any suitable dielectric material, for example, polymeric materials such as PU, PVC, and the like. 
     A tube-like electrode  525  for delivering electrosurgical energy to tissue is disposed coaxially though shaft  520  and is exposed at a distal end  524  of shaft to form a male threaded portion  535   a . An electrically conductive distal tip  522  (shown separated from tube-like electrode  525 ) includes a female threaded portion  535   b  disposed at least partially within the distal tip  522  and configured to receive male threaded portion  535   a  therein in a thread-fit manner to mechanically couple distal tip  522  to tube-like electrode  525  and provide electrical communication therebetween to deliver electrosurgical energy to tissue. Once mechanically coupled to tube-like electrode  525 , distal tip  522  is exposed at a distal end  524  of shaft  520  to form an aspiration port  528  defined therethrough. Tube-like electrode  525  defines a conduit  530  longitudinally through shaft  520  to provide suction to a surgical site via aspiration port  528 . Conduit  530  is in fluid communication with vacuum source  550  via lumen  555 . Tube-like electrode  525  may be formed from any suitable electrically conductive material, including without limitation, aluminum or stainless steel. In embodiments, tube-like electrode  525  may be at least partially exposed at the distal end  525  of shaft  520 . 
     The inner diameter of the distal tip  522  is sized similarly to the outer diameter of tube-like electrode  525  to facilitate the threading of female threaded portion  535   b  of distal tip  522  about male threaded portion  535   a  of tube-like electrode  525 . Once distal tip  522  and tube-like electrode  525  are threaded together in this manner, the outer periphery of distal tip  522  may be configured to be substantially coplanar with the outer periphery of shaft  520  and/or insulating sheath  526  or, alternatively, to be substantially coplanar with the outer periphery of tube-like electrode  525 . 
     In embodiments, distal tip  522  may be between about 0.1 inches and about 0.5 inches in longitudinal length or a longitudinal length sufficient to impede the propagation of thermal energy proximally. 
     Referring now to  FIG. 5B , an embodiment of distal tip  522  may include a wave-like electrical conductor  560  configured to electrically communicate with tube-like electrode  525  when distal tip  522  is threaded to tube-like electrode  525  to deliver electrosurgical energy to tissue during a surgical procedure. In this embodiment, distal tip  522  includes a thermally conductive polymer or so-called “cool polymer” disposed therein to impede the propagation of thermal energy from electrical conductor  560  during a surgical procedure. 
       FIG. 5C  shows another embodiment of distal tip  522  having a plurality of vertical electrical conductors  570  intersected by one or more horizontal electrical conductors  572 . One or more of conductors  570  and  572  are in electrical communication with tube-like electrode  525  when distal tip  522  is threaded to tube-like electrode  525  to deliver electrosurgical energy to tissue during a surgical procedure. In this embodiment, distal tip  522  includes a thermally conductive polymer or so-called “cool polymer” disposed therein to impede the propagation of thermal energy from electrical conductors  570  and  572  during a surgical procedure. 
     Referring now to  FIGS. 6A ,  6 B, and  6 C, another embodiment of the suction coagulator  410  of  FIG. 4  is shown generally as  600 . The suction coagulator  600  is operably coupled to an electrosurgical generator  640  via a conductor  645  and includes a housing  615  disposed proximally to an elongated shaft  620 . Shaft  620  includes an insulating sheath  626  formed from any suitable dielectric material, for example, polymeric materials such as PU, PVC, and the like. 
     A tube-like electrode  625  for delivering electrosurgical energy to tissue is disposed coaxially though shaft  620  and is exposed at a distal end  624  of shaft. Tube-like electrode  625  defines a conduit  630  longitudinally through shaft  620  to provide suction to a surgical site. Conduit  630  is in fluid communication with a vacuum source  650  via a lumen  655 . Tube-like electrode  625  may be formed from any suitable electrically conductive material, including without limitation, aluminum or stainless steel. 
     Suction coagulator  600  further includes an electrically conductive distal tip  622  configured to mechanically couple to tube-like electrode  525  and provide electrical communication therebetween to deliver electrosurgical energy to tissue during a surgical procedure. Distal tip  622  may be mechanically coupled to tube-like electrode  625  by any suitable coupling technique or combination of coupling techniques such as, for example, press-fit, interface-fit, crimping, welding, soldering, adhesive, or any combination thereof. Once mechanically coupled to tube-like electrode  625 , distal tip  622  is exposed at a distal end  624  of shaft  620  to form an aspiration port  628  defined therethrough. Tube-like electrode  625  defines a conduit  630  longitudinally through shaft  620  to provide suction to a surgical site via aspiration port  628 . Conduit  630  is in fluid communication with vacuum source  650  via lumen  655 . Tube-like electrode  625  may be formed from any suitable electrically conductive material, including without limitation, aluminum or stainless steel. In embodiments, tube-like electrode  625  may be at least partially exposed at the distal end  625  of shaft  620 . 
     The inner diameter of the distal tip  622  is sized similarly to the outer diameter of tube-like electrode  625  to facilitate mechanical coupling of distal tip  622  to tube-like electrode  625 . Once distal tip  622  is coupled to tube-like electrode  625  in this manner, the outer periphery of distal tip  622  may be configured to be substantially coplanar with the outer periphery of shaft  620  and/or insulating sheath  626  or, alternatively, to be substantially coplanar with the outer periphery of tube-like electrode  625 . 
     In embodiments, distal tip  622  may be between about 0.1 inches and about 0.5 inches in longitudinal length or a longitudinal length sufficient to impede the propagation of thermal energy proximally. 
     Referring now to  FIG. 6B , an embodiment of distal tip  622  may include a wave-like electrical conductor  660  configured to electrically communicate with tube-like electrode  625  when distal tip  622  is mechanically coupled to tube-like electrode  625  to deliver electrosurgical energy to tissue during a surgical procedure. In this embodiment, distal tip  622  includes a thermally conductive polymer  665  or so-called “cool polymer” disposed therein to impede the propagation of thermal energy from electrical conductor  660  during a surgical procedure. 
       FIG. 6C  shows another embodiment of distal tip  622  having a plurality of vertical electrical conductors  670  intersected by one or more horizontal electrical conductors  672 . One or more of conductors  670  and  672  are in electrical communication with tube-like electrode  625  when distal tip  622  is mechanically coupled to tube-like electrode  625  to deliver electrosurgical energy to tissue during a surgical procedure. In this embodiment, distal tip  522  includes a thermally conductive polymer or so-called “cool polymer” disposed therein to impede the propagation of thermal energy from electrical conductors  670  and  672  during a surgical procedure. 
     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.