BACKGROUND OF THE INVENTION 
       [0001]    A bipolar electrosurgical handpiece is described in U.S. Pat. No. 6,231,571 and D562,978, the contents of which are herein incorporated by reference, an example of which is known commercially as the Trigger-Flex Bipolar System and is available from Elliquence LLC of Oceanside, N.Y. The handpiece comprises an elongated rigid tube within which is housed extendable electrosurgical electrodes, preferably of the bipolar type. By special construction of the distal end of the electrodes, such as by the use of memory metal, when the handle is squeezed the bipolar electrodes, whose spacing is fixed, are extended from their tube and bent in accordance with the presetting of the memory metal. Typically, such an electrosurgical handpiece is employed with a cannula for minimally invasive surgical (MIS) procedures. 
         [0002]    There are certain procedures in which it is desired for the bipolar electrodes to follow a certain path allowing the electrodes to grasp certain tissue before electrosurgical currents are supplied. Examples are general pin-point coagulation in all delicate neurosurgical procedures, transphenoidal surgery, and in certain cases of devascularization of tumors and debulking of lesions/tumors. 
       SUMMARY OF THE INVENTION 
       [0003]    An object of the invention is an improved electrosurgical handpiece for use in performing MIS procedures. 
         [0004]    Another object of the invention is an improved electrosurgical handpiece adapted for grasping tissue in a particular fashion. 
         [0005]    In accordance with one aspect of our invention, a novel electrosurgical handpiece comprises an elongated rigid tubular member housing extendable bipolar electrodes, with the tubular member configured to fit within and be extended down a standard sized cannula in a MIS procedure. Squeezable handles support the tubular member and are configured such that when the handles are squeezed, the active electrode ends are extended out through the cannula end and opened, i.e., spread apart. When the handles are released, the electrode ends are pulled back into the cannula and forced to close. 
         [0006]    A feature of the invention is the configuration of the tips of the bipolar electrode ends, which are formed into flat opposing surfaces, and the relationship of their connecting links to the tubular member. The connecting links are configured such that, as the handles are released, when they first are forced to close as they withdraw into the tubular member, the distal ends of the electrode tips touch first. As they continue withdraw into the tubular member and to close, the flat surfaces are pressed up against one another. This action ensures that any tissue grasped as the tips close is held securely in the tips and not squeezed out. 
         [0007]    As another feature of the invention, the electrode tips can be arranged to extend out in a straight line along an extension of the elongated tube axis, or bent off the axis in order to reach tissue portions not readily accessible from a straight line extension. 
         [0008]    The housed bipolar electrodes as in the referenced patents and application are electrically active and are capable when energized of applying electrosurgical currents to grasped human tissue with the result that a void or cavity or tunnel can be formed in the tissue or bleeders sealed. Any tissue removed may then be easily aspirated via a suction port connected to the handpiece. 
         [0009]    Preferably, radio-frequency (RF) electrosurgical currents, in a frequency range preferably above 3 MHz, with 4 MHz being preferred, are employed. It is believed that 4 MHz radiofrequency energy has been proven to be a self-limiting, minimal penetration energy source capable of precise tissue interaction. Thus, electrosurgical instruments that emit 4 MHz radiofrequency currents will be attractive to spinal or other surgeons needing to produce controlled tissue modulation efficiently and safely. Since lateral heat is typically not a byproduct of 4 MHz RF currents, damage to surrounding tissue can be minimized or avoided. 
         [0010]    Thus, a MIS electrosurgical procedure using the novel system components described herein enables physicians to offer to patients a treatment that is efficiently performed, relatively easily learned and thus performed at a significantly reduced price, and with less tissue damage and superior results compared to procedures done with other devices. 
         [0011]    The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention, like reference numerals or letters signifying the same or similar components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an enlarged plan view from the side of one form of electrosurgical handpiece in accordance with the invention in its relaxed position shown schematically connected to an electrosurgical generator; 
           [0013]      FIG. 2  is a top view of the electrosurgical handpiece of  FIG. 1  also in its relaxed position; 
           [0014]      FIG. 3  is an enlarged top view of the protruding electrode ends of the electrosurgical handpiece of  FIG. 2  in the relaxed non-squeezed handle position shown in  FIG. 1 ; 
           [0015]      FIG. 4  is a side view of the electrosurgical handpiece of  FIG. 1  shown in its fully squeezed handle position; 
           [0016]      FIG. 5  is an enlarged top view of the protruding electrodes of the electrosurgical handpiece of  FIG. 4  in its fully-squeezed position; 
           [0017]      FIG. 6  is a side view of the electrosurgical handpiece of  FIG. 1  shown in its middle or partially relaxed handle position; 
           [0018]      FIG. 7  is an enlarged top view of the protruding electrodes of the electrosurgical handpiece of  FIG. 6  in the partially-relaxed handle position; 
           [0019]      FIG. 8  is a side view of the electrode and its connecting link for the electrosurgical handpiece of  FIG. 1  with a straight electrode; 
           [0020]      FIG. 9  is a top view of the electrode and its link of  FIG. 8 ; 
           [0021]      FIG. 10  is a cross section along the line  10 - 10  of  FIG. 9 . 
           [0022]      FIG. 11  is a side view of a variant of the electrosurgical handpiece of  FIG. 1  in its squeezed position in which the electrode is angled. 
           [0023]      FIG. 12  is a side view of the electrode and its connecting link for the electrosurgical handpiece of  FIG. 11  with an angled electrode; 
           [0024]      FIG. 13  is a top view of the electrode and its link of  FIG. 12 ; 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    The present invention is an improvement of the electrosurgical apparatus described in U.S. Pat. No. 6,231,571; D562,978; and US pending application, Ser. No. 11/799,603, filed May 3, 2007, the contents of which are herein incorporated by reference. In the referenced patents/application, an electrosurgical handpiece is described in which an elongated rigid tube is fixed to the front end handpiece body to which is affixed the front handle portion. Extendable within the rigid tube is an elongated electrode connected to the rear end handpiece body to which is affixed the rear handle portion. When the handles are squeezed, the electrode is extended and bends in a direction preset into the electrode metal. An incorporated compression spring keeps the two body parts apart. The present invention employs the same basic construction except for the configuration of the electrodes so that when extended and retracted they follow a different path. 
         [0026]    Referring now to the drawings, an electrosurgical handpiece  10  in accordance with the invention comprises an elongated rigid tube  12  affixed to the front end body section  14 . Inside the rigid tube  12  extends connected to active bipolar electrode ends  16  is an elongated link  18  (shown in dashed lines) which in turn is fixed to the rear end body section  20 , which telescopes within the front end section  14 . Across the two body sections  14 ,  20 , biased apart by an internal spring shown schematically at  21 , is pivotably  22  mounted the front  24  and rear  26  handle portions, which also pivotably connect  28  at the top. The handle configuration differs from that disclosed in the pending application in that the handle portions above their pivots to the body are angled closer to the body to improve surgeon visibility of the surgical site. 
         [0027]    The handpiece is typically bipolar with two extended electrodes between which the electrosurgical currents are concentrated. One electrode  16  and its extended link  18  is shown in  FIGS. 8-10 . Its companion electrode (not shown) is a mirror image of the one shown. The right end of the shank is connected to the rear body section  20 , so that when the handles are squeezed the electrode end  16  at the left is extended out of the rigid tube  12 . A feature of the invention is the configuration of the electrode  16  and its link  18 . As shown in  FIG. 8 , the left end or distal portion  16  has a short straight flat section  30  with facing surfaces  32  of the active electrode ends that are parallel, electrically bare, and in full contact when the handpiece is in its relaxed position, shown in  FIG. 3 . Back of the distal section  30  the electrode has a short angled section  34  (at about a 45° angle) followed by a longer straight section  36  that extends toward the center axis of the link. As an example, not to be considered limiting, the rigid tube  12  has an inside diameter of about 2.08 mm (0.083 inches), the overall length of the electrode with its link is about 220 mm, the short parallel section  30  in front is about 3 mm long, the following angled short section  34  is about 1.3 mm long, the longer section  36  returning to the axis is about 15 mm long forming an angle of about 9° where it intersects the axis. The thickness of the straight thicker central section of the link is about 0.5 mm. so when the two bipolar electrodes fill the rigid tube, they occupy about ½-⅔ of the internal space. The peak where the short angle section  34  meets the longer straight section  36  is about 3 mm above the electrode axis. As a result of this configuration, when one of the electrode pair  16  is inside the rigid tube  12  in the relaxed position shown in  FIG. 3 , the longer straight section  36  of each electrode half bears against the inside wall of the rigid tube  20  forcing the flat distal ends  30  together with their facing surfaces  32  in full contact. At that position, about ⅔ of the tapered longer sections  36  are inside the rigid tube  12 . 
         [0028]    When the handles are fully squeezed as shown in  FIGS. 4 and 5 , the electrode ends  30  are extended out about ⅘ of the length of the longer sections  36 . Due to the closer spacing of the preset tapered sections  36  still remaining inside the rigid tube, the distal ends  30  spread apart but the opposed surfaces  32  due to the geometry still remain essentially parallel. Now, as shown in  FIG. 7 , as the hand pressure on the handles  24 ,  26  relaxes, the electrodes  18  due to the internal spring  21  pressure are forced back into the rigid tube  12 , and the internal wall pressure on the sections  36  cause the distal ends  30  to approach one another. The configuration of the electrodes are such that the pressure of the rigid tube  12  on the retracting tapered sections  36  forces the extreme electrode ends  40  toward one another faster than the rearward sections with the result that the extreme ends  40  touch first ( FIG. 7 ), before the rest of the front flat sections. In this position, about ½ of the tapered straight sections  36  remain within the rigid tube  12 . Then, as the handles are further relaxed, the remaining parts of the front distal section gradually come together until the position shown in  FIG. 3  is restored with the front sections again in full contact over their full facing surfaces  32 . 
         [0029]    To summarize, when the handles are released, the electrode links  18  are pulled back into the rigid tube acting as a cannula and forced to close. But the tips  30 ,  34  are bent so that when they first begin to close, the extreme ends  40  touch first, and as they continue to close, the flat faces  32  are finally pressed up against one another. This action is extremely important because it allows the surgeon to position the open ends with their extreme tips exactly at the tissue to be grasped and helps to ensure that the tissue is held securely in the tips and not squeezed out during the further closing action. 
         [0030]    In the preferred embodiment, the distal end sections  16  have a semi-circular configuration as illustrated in  FIG. 10  with the flat active surface shown at  32 . 
         [0031]    In the embodiment described above, the active electrode ends  16  extend straight out parallel to the rigid tube axis. In the embodiment illustrated in  FIGS. 11-13 , the active electrode ends are shown at  50  connected as before to an extended link  52 . The bipolar active electrode ends not only spread apart (not shown) as they are extended but also angle off to the left as shown at  50 . They could just as easily angle off to the right if desired. This bending action is similar to that obtained with the handpiece of the referenced patents and is obtained by simply pre-bending the electrodes so that upon their release from the confining action of the rigid tube, they will automatically spread apart as well as angle off to the side as indicated. 
         [0032]    As in the referenced patents/application, when the tissue has been grasped, then the surgeon can apply to the tissue via the electrode ends electrosurgical currents by the usual footswitch connected to a conventional electrosurgical generator  60  ( FIG. 1 ), also available from Elliquence LLC of Oceanside, N.Y. 
         [0033]    While the instrument of the invention is especially useful for spinal procedures, it is not limited to such uses and it will be understood that it can be employed in any electrosurgical procedure employing a cannula in MIS. 
         [0034]    While the invention has been described in connection with preferred embodiments, it will be understood that modifications thereof within the principles outlined above will be evident to those skilled in the art and thus the invention is not limited to the preferred embodiments but is intended to encompass such modifications.
An electrosurgical handpiece comprising a squeezable handle connected to extend and retract bipolar electrodes from a rigid tubular member. The bipolar electrodes comprise active separable distal ends and connecting links configured such that when the handle is unsqueezed, the active distal ends protrude from the distal end of the first tubular member and are adjacent one another, and when the handle is fully squeezed, the active distal ends are fully extended outwardly from the first tubular member and separate, and when the handle is relaxed but still partially squeezed, the active distal ends come together and touch first at their extreme ends and then touch over a broader area in a position to grasp tissue for receiving electrosurgical currents.