Abstract:
A method of treating tissue includes extending a distal tip of an electrode of a surgical instrument from a body of the surgical instrument to expose the distal tip by sliding the electrode along a longitudinal axis defined by the body, delivering energy from the distal tip to tissue, and applying suction adjacent the distal end of the body with a suction pipe of the surgical instrument. The distal tip of the electrode may include a collapsible portion. Extending the distal tip of the electrode may include moving the collapsible portion to extend beyond an outer radial dimension of a nose of the surgical instrument.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of, and priority to, U.S. Provisional Patent Application Nos. 61/906,026 and 61/906,140, both of which were filed on Nov. 19, 2013. This application is related to U.S. patent application Ser. No. 14/521,690, filed on Oct. 23, 2014. The entire contents of each of the above applications are hereby incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to surgical instruments and, more specifically, to surgical instruments including retractable and/or collapsible electrodes for treating, e.g., dissecting and/or coagulating, tissue. 
         [0004]    2. Discussion of Related Art 
         [0005]    The coagulation of bleeding blood vessels and tissue using electrically conductive suction tubes typically includes a combination of electrocautery and a suction device that 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 certain surgical procedure, several layers of tissue must be penetrated to reach the operative field. When excising an organ, such as a gallbladder, the tissue surrounding the organ must often 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. The technique of blunt dissection is often used to prevent unnecessary damage caused by severing these vessels or nerves. 
         [0006]    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. 
         [0007]    Laparoscopy, surgery performed through several small incisions or openings in the body rather than through a single large opening reduces the trauma and the risk of infection as compared to normal, open surgical procedures. The use of conventional blunt dissectors, such as the peanut, during laparoscopic procedures becomes difficult. 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. Thus, the dissection must be stopped, the dissector must be removed, and an irrigator and/or aspirator must be inserted to remove the fluid and debris. 
         [0008]    Electrosurgical suction coagulators which both coagulate and dissect tissue generally include a conductive suction tube having an insulating coating over all but a most distal portion of the tube so that the distal portion forms a generally annular ablating electrode. 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. 
       SUMMARY  
       [0009]    In accordance with the present disclosure, an electrosurgical coagulation instrument is provided including a body, a suction pipe, and an electrode. The body has a central passage that defines a longitudinal axis. The suction pipe has a distal end and defines a lumen. The suction pipe is disposed within the central passage. The electrode has a distal tip that is configured to deliver energy to tissue. The electrode is disposed within the lumen of the suction pipe. The suction pipe and/or the electrode is slidable along the longitudinal axis with respect to the body and the other of the electrode and the suction pipe. 
         [0010]    In aspects of the present disclosure, the suction pipe is operatively associated with a suction pipe actuating member and a suction pipe biasing member. The suction pipe biasing member is configured to urge the suction pipe proximally. the suction pipe actuation member selectively actuatable to move the suction pipe distally against the bias of the suction pipe biasing member. The suction pipe can have a retracted position and a deployed position. In the retracted position, the distal end of the suction pipe is proximal to a distal end of the body. In the deployed position, the distal end of the suction pipe is distal to the distal end of the body. The electrode can be longitudinally fixed relative to the body with the distal tip of the electrode extending from the distal end of the body and the distal end of the suction pipe positioned distal to the distal tip of the electrode when the suction pipe is in the deployed position. 
         [0011]    In some aspects of the present disclosure, the electrode is operatively associated with an electrode actuation member and an electrode biasing member. The electrode biasing member is configured to urge the electrode proximally. the electrode actuating member is selectively actuatable to move the electrode distally against the electrode biasing member. The electrode can have a withdrawn position and an extended position. In the withdrawn position, a distal tip of the electrode is proximal to a distal end of the suction pipe. In the extended position, the distal tip of the electrode is distal to the distal end of the suction pipe. The suction pipe can be longitudinally fixed relative to the body. 
         [0012]    The distal tip of the electrode can have a first position corresponding to the extended position of the electrode and a second position corresponding to the withdrawn position of the electrode. In the first position, the distal tip extends radially outwardly beyond the outer dimension of the suction pipe. In the second position, the distal tip is positioned within the lumen of the suction pipe. 
         [0013]    Also provided in accordance with the present disclosure is an electrosurgical coagulation instrument including a body, a suction pipe, and an electrode. The body includes a nose positioned at a distal end of the body. The nose includes a central passage that defines a longitudinal axis. The suction pipe has a distal end and is disposed within the body. The electrode has a distal tip. The electrode is disposed within the body and configured to deliver energy to tissue. the electrode is slidable along the longitudinal axis with respect to the body. The electrode has a withdrawn position and an extended position. In the withdrawn position, the distal tip of the electrode is positioned within the body proximal to the distal end of the body. In the extended position, a portion of the distal tip of the electrode extends distally from the distal end of the body. 
         [0014]    In aspects of the present disclosure, the distal tip includes a fixed portion and a collapsible portion. The distal tip has a first position and a second position corresponding to the withdrawn position and the extended position of the electrode respectively. In the first position, the collapsible portion is disposed within the radial dimension of the central passage of the body. In the second position, the collapsible portion extends beyond the radial dimensions of the central passage of the body. The fixed portion can include a pivot pin. The collapsible portion can include a cam slot and a cam pin positioned within the cam slot. The cam pin is configured to move within the cam slot to move the collapsible portion from the first position to the second position. The instrument can include a pull link that is coupled to the cam pin. The pull link being configured to move the cam pin within the cam slot to move the collapsible portion from the first position to the second position when the electrode approaches the extended position. The instrument can include a tip biasing member that is positioned about the pivot pin. The tip biasing member being configured to urge the collapsible portion towards the first position. 
         [0015]    In another aspect of the present disclosure, the instrument includes an actuation assembly having a fixed magnet, a sliding magnet, and an inductive coil. The inductive coil is positioned about the fixed magnet. The sliding magnet is slidable along the longitudinal axis of the body and is coupled to the electrode. When the inductive is energized, the fixed magnet attracts the sliding magnet such that the sliding magnet slides distally and extends the electrode. The actuation assembly can include a magnet biasing member that urges the sliding magnet proximally. the actuation assembly can include proximal and distal stops configured to limit the longitudinal movement of the sliding magnet. The distal stop can include a mechanical activation switch configured to activate the electrode when the sliding magnet is adjacent the distal stop. 
         [0016]    In yet another aspect of the present disclosure, the body includes a chamber positioned at a proximal end of the central passage. The chamber in fluid connection with the distal end of the body. The instrument can further include an irrigation pipe having a distal end. the distal ends of the suction pipe and the irrigation pipe positioned at and in fluid connection with the chamber. The distal end of the suction pipe can include a directional valve configured to permit fluid to flow from the chamber to the suction pipe and configured to inhibit fluid from flowing from the suction pipe to the chamber. The distal end of the irrigation pipe can include a directional valve configured to permit fluid to flow from the irrigation pipe to the chamber and configured to inhibit fluid from flowing from the chamber to the irrigation pipe. 
         [0017]    Methods of treating tissue provided in accordance with the present disclosure include extending a distal tip of an electrode of a surgical instrument from a body of the surgical instrument to expose the distal tip by sliding the electrode along a longitudinal axis defined by the body, delivering energy from the distal tip to tissue, and applying suction adjacent the distal end of the body with a suction pipe of the surgical instrument. 
         [0018]    In aspects of the present disclosure, delivering energy from the distal tip to tissue and applying suction adjacent the distal end of the body are performed simultaneously. The method may include retracting the distal tip of the electrode into the body before applying suction adjacent the distal end of the body. The method may include irrigating adjacent the distal end of the body with a fluid exiting through a nose of the body. The method may include concealing the distal tip of the electrode from the second position back to the first position after delivering energy from the distal tip to tissue and before applying suction adjacent the distal end of the body. 
         [0019]    In aspects of the present disclosure, the surgical instrument includes an actuation assembly that includes an inductive coil. Extending the distal tip of the electrode may include energizing the inductive coil to effect sliding of the electrode. The actuation assembly may also include a mechanical activation switch and a sliding magnet. The sliding magnet may be disposed within the inductive coil and engaged to the electrode. In embodiments, delivering energy from the distal tip to tissue includes engaging the mechanical activation switch with the sliding magnet to energize the electrode. 
         [0020]    In aspects of the present disclosure, extending the distal tip of the electrode includes extending a portion of the distal tip from a first position to a second position. In the first position, the distal tip is disposed within an outer radial dimension of a distal end of the body and in the second position, the portion of the distal tip extends beyond the outer radial dimension. 
         [0021]    In aspects of the present disclosure, the distal tip of the electrode may include a collapsible portion. Extending the distal tip of the electrode may include moving the collapsible portion to extend beyond an outer radial dimension of a nose of the surgical instrument. The method may include retracting the distal tip of the electrode within the body such that the portion of the collapsible portion is returned to within the outer radial dimension of the nose. 
         [0022]    In yet another aspect of the present disclosure, a method of treating tissue includes exposing a distal tip of an electrode of a surgical instrument from a first position to a second position, delivering energy from the distal tip to tissue, and applying suction with the suction pipe adjacent the distal end of the body. In the first position, the distal tip is disposed within a lumen of the suction pipe of the surgical instrument and in the second position, the distal tip of the electrode extends from the distal end of the suction pipe. 
         [0023]    In aspects of the present disclosure, exposing the distal tip of the electrode from the first position to the second position includes retracting the suction pipe from about the distal tip of the electrode. The method may include extending the suction pipe about the distal tip of the electrode after delivering energy from the distal tip to tissue and before applying suction adjacent the distal end of the suction pipe. 
         [0024]    In aspects of the present disclosure, exposing the distal tip of the electrode from the first position to the second position includes extending a portion of the electrode beyond an outer dimension of the distal end of the suction pipe. In the second position, the distal tip of the electrode may extend beyond an outer radial dimension of the distal end of the suction pipe. 
         [0025]    By providing a surgical instrument including a collapsible distal tip the electrode of the instrument can have an activatible tip with a surface area larger than the outer dimension of the suction pipe and or the access port used to access the body cavity. This may provide a clinician the ability to quickly dissect and coagulate tissue reducing the time required to complete a surgical procedure. 
         [0026]    Further, to the extent consistent, any of the aspects described herein may be used in conjunction with any or all of the other aspects described herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    Various aspects of the present disclosure are described hereinbelow with reference to the drawings, wherein: 
           [0028]      FIGS. 1A and 1B  are perspective and cross-sectional views, respectively, of a electrosurgical coagulation instrument in accordance with the present disclosure with the suction pipe in the retracted position; 
           [0029]      FIGS. 2A and 2B  are perspective and cross-sectional views, respectively, of the instrument of  FIGS. 1A and 1B  with the suction pipe in the deployed position; 
           [0030]      FIGS. 3A and 3B  are perspective and cross-sectional views, respectively, of another electrosurgical coagulation instrument in accordance with the present disclosure with the electrode in the withdrawn position; 
           [0031]      FIGS. 4A and 4B  are perspective and cross-sectional views, respectively, of the instrument of  FIGS. 3A and 3B  with the electrode in the extended position; 
           [0032]      FIG. 5  is a perspective view of yet another electrosurgical coagulation instrument in accordance with the present disclosure with the suction pipe in the retracted position and the electrode in the withdrawn position; 
           [0033]      FIG. 6  is a perspective view of the instrument of  FIG. 5  with the suction pipe in the deployed position and the electrode in the extended position; 
           [0034]      FIG. 7  is a perspective view of the instrument of  FIG. 3  incorporating another electrode in the extended position in accordance with the present disclosure; 
           [0035]      FIG. 8  is a cross-sectional view of the instrument of  FIG. 7  with the electrode in the withdrawn position; 
           [0036]      FIG. 9  is a cross-sectional view of still another electrosurgical coagulation instrument in accordance with the present disclosure with the electrode in the withdrawn position; 
           [0037]      FIG. 10  is a cross-sectional view of the instrument of  FIG. 9  with the electrode in the extended position; 
           [0038]      FIG. 11  is an enlarged cross-sectional view of the distal tip assembly of the instrument of  FIG. 9  in the withdrawn condition; and 
           [0039]      FIG. 12  is an enlarged cross-sectional view of the distal tip assembly of the instrument of  FIG. 9  in the extended condition. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term “clinician” refers to a doctor, a nurse, or any other care provider and may include support personnel. Throughout this description, the term “proximal” will refer to the portion of the device or component thereof that is closest to the clinician and the term “distal” will refer to the portion of the device or component thereof that is furthest from the clinician. 
         [0041]    Referring now to  FIGS. 1A and 1B , an electrosurgical coagulation surgical instrument  10  is provided in accordance with the present disclosure incorporating a body  20 , an extendable suction pipe  30 , and an electrode  40 . Body  20  includes a proximal end  22 , a distal end  24 , and a central passage  25  extending between the proximal and distal ends  22 ,  24 . In embodiments, body  20  includes a longitudinal slot  26  extending through body  20  and into central passage  25 . 
         [0042]    Suction pipe  30  includes a proximal end  32 , a suction tip or distal end  34 , and a lumen  35  extending between proximal and distal ends  32 ,  24 . Suction pipe  30  is slidably positioned within central passage  25  of body  20 . Suction pipe  30  is operatively associated with a suction device (not shown) by a suction port  38 . In embodiments, a suction pipe biasing member  37  is disposed about the outer surface of suction pipe  30  within body  20 . Suction pipe biasing member  37  urges suction pipe  30  proximally towards a retracted position. In some embodiments, a suction pipe actuating member  36  is coupled to the outer surface of suction pipe  30  and extends through longitudinal slot  26  to permit deployment of suction pipe  30 . In certain embodiments, distal end  34  of suction pipe  30  includes a plurality of holes  34   a  configured to improve suction (see  FIGS. 2A and 2B ). Suction pipe  30  is configured to suction fluids through distal end  34  with the fluids exiting suction pipe  30  through suction port  38 . 
         [0043]    Electrode  40  includes a proximal end  42  and a distal tip  44 . Electrode  40  is disposed within lumen  35  of suction pipe  30  and is longitudinally fixed relative to body  20 . Electrode  40  is operatively associated with an energy source (not shown). In embodiments, proximal end  42  of electrode  40  is connected to the energy source. The energy source is configured to provide energy that is delivered to tissue through electrode  40 . Electrode  40  can be configured as a monopolar electrode, a bipolar electrode, a microwave electrode, an ultrasonic blade, etc. 
         [0044]    Electrode  40  has an activated state and an inactivate state. In the activated state, the energy source provides energy to electrode  40  enabling electrode  40  to deliver the energy to tissue to dissect and coagulate tissue at distal tip  44 . In the inactivate state, energy is not delivered to tissue through distal tip  44  of electrode  40 . It will be appreciated that as energy is delivered to tissue through distal tip  44 , distal tip  44  can increase in temperature. Instrument  10  can include an activation button (not shown) for selectively supplying energy to electrode  40  or may be configured to automatically supply energy to electrode  40  when suction pipe  30  is retracted. 
         [0045]    With additional reference to  FIGS. 2A and 2B , suction pipe  30  has a retracted position ( FIGS. 1A and 1B ) and a deployed position ( FIGS. 2A and 2B ). In the retracted position, distal end  34  of suction pipe  30  is near distal end  24  of body  20 . In some embodiments, distal end  34  of suction pipe  30  is proximal to distal end  24  of body  20  when suction pipe  30  is in the retracted position. In the deployed position, distal end  34  of suction pipe  30  is extended past distal tip  44  of electrode  40 . In some embodiments, suction pipe actuation member  36  is moved distally to extend suction pipe  30  against suction pipe biasing member  37 . In certain embodiments, the length of longitudinal slot  26  defines the range of longitudinal movement of suction pipe  30  between the retracted position and the deployed position by interacting with suction pipe actuation member  36 , i.e., the proximal and distal ends of longitudinal slot  26  function as stops defining the extent of longitudinal movement of suction pipe  30 . Suction pipe  30  is configured to provide suction in its retracted position and/or in its deployed position. 
         [0046]    Referring now to  FIGS. 3A and 3B , another electrosurgical coagulation surgical instrument  110  is provided in accordance with the present disclosure incorporating a body  120 , a suction pipe  130 , and an extendable electrode  140 . Body  120  is substantially similar to body  20  and includes a proximal end  122 , a distal end  124 , and a central passage  125  extending between the proximal and distal ends  122 ,  124 . In embodiments, body  120  includes a longitudinal slot  126  extending through body  120  and into central passage  125 . 
         [0047]    Suction pipe  130  includes a proximal end  132 , a distal end  134 , and a lumen  135  extending between proximal and distal ends  132 ,  134 . Suction pipe  130  is longitudinally fixed relative to body  120  within central passage  125  of body  120  such that distal end  134  of suction pipe  130  extends proximally from distal end  124  of body  120 . Suction pipe  130  is operatively associated with a suction device (not shown) by a suction port  138 . In embodiments, distal end  134  of suction pipe  130  includes a plurality of holes  134   a  configured to improve suction. Suction pipe  130  is configured to suction fluids through distal end  134  with the fluids exiting suction pipe  130  from suction port  138 . 
         [0048]    Electrode  140  includes a proximal end  142  and a distal tip  144 . Electrode is slidably disposed within lumen  135  of suction pipe  130 . Electrode tip  140  is operatively associated with an energy source (not shown). In embodiments, proximal end  142  of electrode is connected to the energy source. Electrode  140  is configured to dissect and coagulate tissue by delivering energy to tissue near or in contact with distal tip  144 . In embodiments, an electrode biasing member  147  is disposed about the outer surface of suction pipe  130  within body  120 . Electrode biasing member  147  urges electrode  140  proximally. In some embodiments, an electrode actuating member  146  is coupled to the outer surface of electrode  140  and extends through longitudinal slot  126 . In certain embodiments, electrode biasing member  147  engages electrode actuation member  146  to urge electrode  140  proximally. Electrode  140  has an activated state and an inactivate state similar to electrode  40  discussed above, as such only the differences will be discussed in detail below. 
         [0049]    With additional reference to  FIGS. 4A and 4B , electrode  140  has a withdrawn position ( FIGS. 3A and 3B ) and an extended position ( FIGS. 4A and 4B ). In the withdrawn position, distal tip  144  of electrode  140  is proximal to distal end  134  of suction pipe  130 . In the extended position, distal tip  144  of electrode  140  extended such that distal tip  144  is positioned distally of distal end  134  of suction pipe  130  and is free to contact tissue. In embodiments, electrode actuating member  146  is moved distally to extend electrode  140  against electrode biasing member  147 , e.g., suction pipe  130  can include a slot (not shown) permitting electrode biasing member  147  to engage electrode  140 . In some embodiments, longitudinal slot  126  of body  120  defines the range of longitudinal movement of electrode  140  between the withdrawn position and the extended position by interacting with electrode actuation member  146 , i.e. the proximal and distal ends of longitudinal slot  126  function as stops defining the amount of longitudinal movement of electrode  140 . In certain embodiments, electrode  140  is activatable only in the extended position. In particular embodiments, the distal end of longitudinal slot  126  includes an activation switch  126   a  which is engaged by electrode actuation member  146  when electrode actuation member  146  approaches the distal end of longitudinal slot  126 . Activation switch  126   a  can be a contact switch, a push button switch, a micro switch, a lever switch, etc. 
         [0050]    Referring to  FIGS. 5 and 6 , yet another electrosurgical coagulation surgical instrument  210  is provided in accordance with the present disclosure incorporating a body  220 , an extendable suction pipe  230 , and an extendable electrode  240 . Body  220  is substantially similar to body  20  and includes a proximal end  222 , a distal end  224 , and a central passage (not shown) extending between the proximal and distal ends  222 ,  224 . In embodiments, body  220  includes two longitudinal slots  226   p ,  226   d  extending through body  220  and into the central passage. 
         [0051]    Suction pipe  230  is substantially similar to suction pipe  30  of instrument  10  and includes proximal and distal ends  232 ,  234  and a lumen (not shown) extending between proximal and distal ends  232 ,  224 . Suction pipe  230  is slidably positioned within the central passage of body  220 . Suction pipe  230  is operatively associated with a suction device (not shown) by a suction port  238 . In embodiments, a suction pipe biasing member (not shown) is disposed about the outer surface of suction pipe  230  within body  220 . The suction pipe biasing member urges suction pipe  230  proximally. In some embodiments, a suction pipe actuating member  236  is disposed about the outer surface of suction pipe  230  and extends through longitudinal slot  226   p  to engage suction pipe  230 . In certain embodiments, distal end  234  of suction pipe  230  includes a plurality of holes configured to improve suction. Suction pipe  230  is configured to suction fluids through distal end  234  with the fluids exiting suction pipe  230  through suction port  238 . 
         [0052]    Electrode  240  is substantially similar to electrode  140  and includes a proximal end  242  and a distal tip  244 . Electrode  240  is slidably disposed within lumen  235  of suction pipe  230 . Electrode tip  244  is operatively associated with an energy source (not shown). In embodiments, proximal end  242  of electrode  240  is connected to the energy source. Electrode  240  is configured to dissect and coagulate tissue by delivering energy to tissue through distal tip  244 . In embodiments, an electrode biasing member (not shown) is disposed about the outer surface of suction pipe  230  within body  220 . The electrode biasing member urges electrode  240  proximally. The electrode biasing member (not shown) can be positioned distal to the suction pipe biasing member (not shown). In some embodiments, an electrode actuating member  246  is coupled to the outer surface of electrode  240  and extends through the other longitudinal slot  226   d . In certain embodiments, the electrode biasing member engages electrode actuating member  246  to urge electrode  240  proximally. Electrode  240  has an activated state and an inactivate state similar to electrode  40  discussed above, as such only the differences will be discussed in detail below. 
         [0053]    Suction pipe  230  has a retracted position and a deployed position similar to suction pipe  30 . Electrode  240  has a withdrawn position and an extended position similar to electrode  140 , as such only the differences will be discussed. Suction pipe  230  and electrode  240  are selectably and independently movable relative to body  220 . 
         [0054]    Referring to  FIGS. 7 and 8 , another electrode  340  is provided in accordance with the present disclosure incorporating a proximal end  342  and a collapsible distal tip  344 . Electrode  340  is similar to electrodes  40 ,  140 , and  240 , as such only the differences will be discussed in detail below. Electrode  340  is shown in use with instrument  110  but it will be appreciated that electrode  340  can also be used with instruments  10  and  210  as an alternative to electrodes  40  and  240 , respectively, or with any other suitable surgical instrument. 
         [0055]    Collapsible distal tip  344  of electrode  340  includes a proximal portion  344   a  and a distal portion  344   b . Collapsible distal tip  344  is biased towards a second position ( FIG. 7 ) such that when collapsible distal tip  344  is positioned distal to distal end  134  of suction pipe  130 , distal portion  344   b  extends beyond the dimensions of the outer surface of suction pipe  130 , i.e., distal portion  344   b  crosses the longitudinal axis of instrument  110  and extends for a length greater than the radius of suction pipe  130  along an axis orthogonal to the longitudinal axis of instrument  110 . In some embodiments when in the second position, distal portion  344   b  extends along an axis orthogonal to the longitudinal axis of instrument  110  beyond the outer surface of both sides of suction pipe  130  such that the length of distal portion  344   b  is greater than the diameter of suction pipe  130 . Collapsible distal tip  344  also has a first position ( FIG. 8 ) when collapsible distal tip  344  is positioned proximal to the distal end  134  of suction pipe  130  and within suction pipe  130 , e.g., when confined within suction pipe  130 . When in the first position, the inner surface of suction pipe  130  interacts with collapsible distal tip  344  to constrain distal tip  344  in the first position such that distal portion  344   b  is within lumen  135 , e.g., within the outer dimensions of suction pipe  130 , as shown in  FIG. 8 . Electrode  340  can be constructed of a material having a resilient bias towards the second position or may be formed from a shape-memory material such as Nitnol. 
         [0056]    Referring to  FIGS. 9-12 , yet another electrosurgical coagulation instrument  410  provided in accordance with the present disclosure incorporates a body  420 , a suction pipe  430 , an electrode  440 , an irrigation pipe  450 , and an actuation assembly  460 . Body  420  includes a suction tip or nose  421 , a proximal end  422 , a chamber  423 , a distal end  424 , and a central passage  425 . Body  420  can be constructed from a biocompatible plastic material or other suitable material. Central passage  425  is disposed within nose  421  and fluidly connects chamber  423  and distal end  424 . Distal end  424  can include a metal insert or sleeve  424   a  positioned in an inner surface of distal end  424 . Metal insert  424   a  can be configured to protect plastic body  420  from damage by a heated distal tip assembly  444 , although the insert can be constructed of any material suitable to protect plastic body  420  from a heated distal tip assembly  444 . Chamber  423  forms a fluid seal at the proximal end of central passage  425 . 
         [0057]    Suction pipe  430  has a proximal end  432  and a distal end  434 . Distal end  434  is fluidly coupled to chamber  423  through a valve  433 . Valve  433  can be a directional valve permitting fluid to flow from chamber  423  into suction pipe  430 . In embodiments, proximal end  432  of suction pipe  430  is connected to a vacuum source  439  that is configured to draw fluid from chamber  423 . 
         [0058]    Irrigation pipe  450  has a proximal end  452  and a distal end  434 . Distal end  434  is fluidly coupled to chamber  423  through a valve  453 . Valve  453  can be a directional valve permitting fluid to flow from irrigation pipe  450  into chamber  423 . In embodiments, proximal end  452  of irrigation pipe  450  is connected to an irrigation source  459  that provides fluid for irrigation pipe  450 . 
         [0059]    Electrode  440  includes a proximal end  442  and a distal tip assembly  444 . Distal tip assembly  444  includes a fixed portion  445 , a collapsible portion  446 , and a pivot pin  449  as shown in  FIGS. 11 and 12 . Distal tip assembly  444  can define various configurations, i.e., straight, curved, angled, etc. Fixed portion  445  has a cam slot  445   a . Collapsible portion  446  is pivotally coupled to fixed portion  445  by pivot pin  449  and includes a cam pin  446   a  slidably positioned within cam slot  445   a  of fixed portion  445 . A pull link  448  is coupled to cam pin  446   a  to move cam pin  446   a  within cam slot  445   a  and is configured to extend collapsible portion  446  as discussed in detail below. Alternatively, electrode  440  may employ the features of electrode  340  ( FIGS. 7 and 8 ). 
         [0060]    Electrode  440  has a withdrawn position ( FIG. 9 ) and an extended position ( FIG. 10 ). In the withdrawn position, distal tip assembly  444  is positioned within chamber  423  and in the extended position distal tip assembly  444  is positioned beyond distal end  424  of body  420 . Actuation assembly  460  is configured to move electrode  440  from the withdrawn position to the extended position. 
         [0061]    Actuation assembly  460  includes a fixed magnet  461 , an inductive coil  462 , a sliding magnet  464 , and an actuation button  469 . Fixed magnet  461  is positioned distal of sliding magnet  464 . Actuation button  469  is electrically coupled to inductive coil  462  to energize inductive coil  462 . Inductive coil  462  is position about fixed magnet  461  and configured to control the magnetic field of fixed magnet  461  when energized as discussed below. Sliding magnet  464  is coupled to electrode  440  such that electrode  440  cooperates with longitudinal movement of sliding magnet  464 . Electrode  440  can pass through an opening or slot in fixed magnet  461  such that fixed magnet  461  does not interfere with the longitudinal movement of electrode  440 . Sliding magnet  464  is positioned between proximal stops  465  and distal stops  466 . A magnet biasing member  467  is supported on fixed magnet  461  and configured to urge sliding magnet  464  proximally. Distal stops  466  can include a mechanical activation switch  468  that is configured to energize electrode  440 . Mechanical activation switch  466  can be a plunger, a cantilever switch, a contact switch, etc. 
         [0062]    When inductive coil  462  is energized, inductive coil  462  induces the magnetic field of fixed magnet  461  to attract sliding magnet  464  distally towards fixed magnet  461  and against magnet biasing member  467 . As sliding magnet  464  moves distally, electrode cooperates with sliding magnet  464  to extend distal tip assembly  444  distally beyond distal end  424  of body  420 . Distal stops  466  are positioned such that sliding magnet  461  contacts distal stops after distal tip assembly  444  extends from distal end  424  of body  420 . When distal stops  466  include mechanical activation switch  468 , sliding magnet  464  engages mechanical activation switch  468  to energize electrode  440  only when distal tip assembly  444  extends beyond distal end  424 . Moreover, if an external force moves electrode  440  proximally, sliding magnet can disengage mechanical activation switch  468 , for example, electrode  440  could be pressed against tissue and moved proximally relative to body  420 . 
         [0063]    Collapsible portion  446  has a first position ( FIG. 11 ) and a second position ( FIG. 12 ). A tip biasing member  449   a  is positioned on pivot pin  449  to urge collapsible portion  446  towards the first position. Tip biasing member  449   a  can be a torsion spring. When collapsible portion  446  is in the first position, distal tip  444  is within the dimensions of central passage  425  of nose  421 . Pull link  448  is configured to move collapsible portion  446  to the second position, against tip biasing member  449   a , when electrode  440  is in the second position by moving cam pin  446   a  within cam slot  445   a . When collapsible portion  446  is in the second position a portion of distal tip assembly  444  is beyond the outer dimension of nose  421  as shown in  FIG. 12 . In embodiments, collapsible portion  446  automatically moves to the second position when distal tip assembly  444  is extended beyond distal end  424  of body  420 . In certain embodiments, pull link  448  automatically moves cam pin  446   a  within cam slot  445   a  when distal tip assembly  444  approaches the extended position and is beyond distal end  424  of body  420 . 
         [0064]    While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.