Abstract:
A disposable or reusable bipolar or unipolar electrosurgical handpiece having an extendable and retractable active electrode end and housed in a relatively inexpensive body comprising an actuating handle for use in various electrosurgical procedures. The housing comprises slidable body sections with one of the sections having an internal structure configured for receiving an incoming wire whose stripped end or ends can be contacted to the active electrode end by way of an externally-exposed electrically-conductive band on the electrode.

Description:
RELATED APPLICATIONS 
     U.S. application Ser. No. 09/303,839, filed May 3, 1999, commonly owned, for “Electrosurgical Handpiece For Treating Tissue”, now U.S. Pat. No. 6,231,571. 
     U.S. application Ser. No. 09/393,286, filed Sep. 10, 1999, commonly owned, for “Electrosurgical Handpiece For Treating Tissue”, now U.S. Pat. No. 6,210,409. 
     U.S. application Ser. No. 09/483,994, filed Jan. 18, 2000, commonly owned, for “Electrosurgical Handpiece For Treating Tissue”, now U.S. Pat. No. 6,352,533. 
     This invention relates to an electrosurgical handpiece and an activator for an electrosurgical handpiece. 
     BACKGROUND OF THE INVENTION 
     Our prior application Ser. No. 09/303,839, describes a novel electrosurgical handpiece for treating tissue in a surgical procedure commonly known as minimally invasive surgery (MIS). Among the features described and claimed in the prior application is an electrosurgical handpiece that can be used in MIS and reduces the danger of excessive heat causing possible patient harm. This is achieved in one embodiment by an electrosurgical handpiece that is bipolar in operation and that is configured for use in MIS. The bipolar operation confines the electrosurgical currents to a small active region between the active ends of the bipolar electrode and thus reduces the possibility that excessive heat will be developed that can damage patient tissue. Moreover, the position of the active region can be controlled to avoid patient tissue that may be more sensitive to excessive heat. Preferably, the handpiece is provided with a dual compartment insulated elongated tube, each of the compartments serving to house one of the two wires of the bipolar electrodes. The electrode for MIS use is preferably constructed with a flexible end controllable by the surgeon so as to allow the surgeon to manipulate the end as desired during the surgical procedure. In a preferred embodiment, the flexible end is achieved by weakening at the end the housing for the electrode, and providing a pull string or wire connected to the weakened housing end and with a mechanism at the opposite end for the surgeon to pull the string or wire to flex the housing end to the desired position. This feature allows the surgeon to position the active electrode end at the optimum location for treating, say, a herniated disk to remove undesired regions and to provide controlled heat to shrink the tissue during surgery. In FIGS. 3–7 of the prior application, a suitable bipolar electrode is described, which comprises a pair of rounded electrodes with spaced flat sides separated by an insulating layer. FIGS. 8–10 illustrate a suitable unipolar electrode construction of the flexible end handpiece. FIG. 12 illustrates how such an electrode can be used for the reduction of herniated disks in a laparoscopic procedure. FIG. 19 shows a construction that combines both a bipolar and a unipolar electrode either of which can be selected by the surgeon for use with the procedure. FIG. 20 shows a scissors end that can be constructed as a bipolar electrode for certain purposes. Other constructions to provide easier flexing of the handpiece end, as well as the use of memory metals to control the position of the extended electrode are also discussed. 
     Our prior application Ser. No. 09/393,286, describes a modified bipolar electrode construction using the flexible end handpiece, the modified bipolar electrode having spaced prongs. 
     Our prior application Ser. No. 09/483,994, describes a modified bipolar electrode construction using the flexible end handpiece, the modified bipolar electrode having spaced loops. 
     One limitation of the handpiece constructions described in these prior applications is the relatively high fabrication costs, which deters single uses of the handpiece by the surgeon. Nowadays, surgeons prefer if feasible disposable instruments that can be discarded after one use and no longer need sterilization and sterile packaging for future uses. 
     SUMMARY OF THE INVENTION 
     The present invention continues the teachings of the three prior applications and hereby incorporates by reference the total contents of the three prior applications, Ser. Nos. 09/303,839, 09/393,286, and 09/483,994. The present invention describes and claims among other things a relatively inexpensive handpiece construction for such instruments with flexible tips. Since the present application otherwise makes use of the same teachings of the prior applications, it was felt unnecessary to repeat in the body of this specification many of the details present in the contents of the prior application. The present description will be confined solely to the modifications in the handpiece construction that allow for inexpensive fabrication and hence disposability if desired but which can still use most if not all of the features described in the incorporated applications yet which will still achieve the same benefits as with the constructions of the prior applications. More specifically, the construction of the present invention can provide both bipolar and unipolar operation separately or in the same handpiece, and can use the same constructions described in the prior applications for providing the extendable and retractable straight and/or curved active electrode tips, as well as many of the details for providing a flexible end or a straight end with a curved extendable electrode, including use in the various medical procedures described in the prior applications and known to others in this art in which electrosurgical currents are used to modulate patient tissue, meaning to cut, ablate, shrink, and/or coagulate tissue. For more details, the reader is directed to the prior applications. 
     The new handpiece constructions of the present improvement are focused for the most part at the gun or handle end of the handpiece, meaning the part of the handpiece held in the hand of the surgeon and operable by the surgeon to extend and retract the flexible tip. 
     In a preferred embodiment, the handle end of the handpiece is constructed preferably of known plastics, and thus can be, for example, molded in several parts and simply assembled by being force-fitted and/or adhered together by suitable adhesives, or snapped together as is well known in the art for assembling plastic members. Preferably, all parts of the handle end except for electrical terminals, optionally a metal spring, and the electrode assembly are made of inexpensive plastic. 
     In accordance with another preferred embodiment, the electrical terminal(s) is or are provided by an electrical wire having one or more stripped ends extending into and around a contact member and being at the contact member in surface contact with one or more exposed electrically-conductive surfaces of the electrode. In this preferred embodiment, assembly of the structure establishes the desired permanent contact of the incoming electrical wire to the active electrode. 
     In a further preferred embodiment, the handle is a one-piece member connected across slidable body parts configured such that squeezing of the handle by the surgeon causes the body parts to come together which action causes the active end of the electrode to extend out of a supporting tube. 
     The constructions of the invention will provide the same important benefits not only for MIS of herniated disks but also for other MIS procedures where controlled electrode position and/or controlled heat generation is of importance as described in the prior applications, as well as for general electrosurgical procedures where the volumetric reduction of tissue is desirable. 
     While the invention of the handpiece of the invention has focused on low-cost fabrication allowing disposability or one-time use, it will be understood by those skilled in this art that the same handpiece can also be reusable if the practitioner so desires, by appropriate sterilization after each use. Most forms of sterilization can be used by an appropriate choice of handpiece materials, such as high-temperature plastics, but gas sterilization as is well known in this art can also be used if heat-sensitive material may be present. 
     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 designating the same or similarly functioning parts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of one form of electrosurgical handpiece in accordance with the invention with the working end shown in its retracted position; 
         FIG. 2  is a vertical cross-sectional view of the electrosurgical handpiece of  FIG. 1 ; 
         FIG. 3  is a vertical cross-sectional view of the electrosurgical handpiece of  FIG. 1  but with the electrode extended into operating position; 
         FIG. 4  is an exploded view of the electrosurgical handpiece of  FIG. 1 ; 
         FIG. 5  is a partly cross-sectional view of the electrode tube housing of the electrosurgical handpiece of  FIG. 1 , also illustrating some of the electrical connections of the electrosurgical electrode used in  FIG. 1 ; 
         FIG. 6  is an enlarged view of part of the contact cap of the electrosurgical handpiece of  FIG. 1 ; 
         FIG. 7  illustrates how the contact cap makes electrical connections to the electrode tube housing; 
         FIG. 8  is an enlarged cross-sectional view of part of the construction of the electrosurgical electrode used in the handpiece of  FIG. 1  illustrating one way of making the contact surfaces on the electrode; 
         FIG. 9  is a cross-sectional view along the line  9 — 9  of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The reader is directed to the referenced prior applications for a more detailed description of the prior applications which will assist in understanding the improvements offered by the present application. 
     In the present application, the electrode configuration remains essentially the same. It can comprise the use of a pulling wire to flex a flexible end of an outer tube housing for the electrode while simultaneously extending the electrode from the end of the outer tube. Or, preferably, the outer tube end is not flexible, but the electrode distal end  116  is constituted of memory metal or has been given a pre-bent contour such that, when extended from its outer tube housing  18 , it assumes a preset curved or straight position that allows the surgeon to reach with the active end of the electrode patient sites behind, say, other tissues more easily. Other electrode constructions that allow the surgeon to extend an active electrode end from an elongated tubular member and cause the active electrode end to assume straight or curved configurations are also considered within the scope of the present invention. 
       FIG. 1  shows one form of electrosurgical handpiece  10  of the invention. It comprises a squeezable handle  12  connected to and across two front  14  and rear  16  main slideable body parts enclosing an elongated outer tubular housing  18  from whose distal end  20  an inner electrode  22  with adjacent active bipolar tips  24  can be extended and retracted when the handle  12  is squeezed or released, respectively. At the left end an electrical cord  26  is terminated in a plug connector  28 . Internally of the handpiece, wires of the electrical cord  26  are connected to the active electrode  22 . 
     The cross-section of  FIG. 2  shows the internal construction. The outer tubular housing  18  extends from the front at the right completely through the center of the front body part  14  and into the coaxially-aligned rear body part  16  and terminates in the latter where indicated at  30 . The front body part  14  contains a bore  32  which houses a compression spring  34  engaged by a reduced diameter projecting member  36  of the rear body part  16 . The compression spring  34  biases apart the two body parts  14 ,  16 . The single-piece handle  12  prevents the body parts  14 ,  16  from coming apart. The front body part  14  also has a forwardly-projecting cylindrical collet  38  containing several longitudinal slits  40 . Two of the slits are shown in  FIG. 2 , through which slits the cross-sectional view was taken which is why the slits are not hatched. Onto the forwardly-projecting collet  38  is mounted a nose piece  42  with an internal tapered bore (not shown) which is configured to cooperate in the conventional manner with the collet  38  so that when the nose piece is forced onto the forwardly-projecting collet  38 , the collet part closes along the slits and locks to the outer tubular housing  18 . In the embodiment shown, the nose piece  42  is permanently secured to the collet  38  so that the electrode is not changeable, but the handpiece construction can be modified to allow for a changeable outer tubular housing  18 . This is easily accomplished by providing the collet  38  with outer screw threads and the nose piece bore with inner screw threads allowing the nose piece to be loosened for removal of the outer tubular housing  18 , and replacement with another housing. In the exploded view of  FIG. 4 , only part of the electrical wire  26  is shown. 
     The rear body part  16  comprises a contact cap  44  made up of upper  46  and lower  48  cap parts. These two cap parts are essentially identical, each comprising a generally cylindrical body  50  with a central bore  52  (when assembled), a forwardly-projecting part  54 , and a rearwardly-projecting part  56 . The latter engages a collar member  58  which holds together the assembled parts. The forwardly-projecting part  54  comprises laterally-spaced axially extending grooves  60 ,  64 , radial holes  66 , and longitudinally-spaced circumferential grooves  68  which function to secure the end of the incoming wire  26  and make a reliable electrical surface contact between the active electrode and the wire ends. In a preferred embodiment for a bipolar construction, this is accomplished as follows (see  FIGS. 6–9 ). The electrode  22  in this case is made, like the main body parts, of an electrically-insulating material, such as any of well-known moldable plastics. It can be divided into two internal compartments  70 ,  72  housing electrically-insulated wires  74  each connected to one of the active bipolar electrode tips  24 . Openings  76  are provided at two longitudinally-spaced and laterally-spaced side portions of the tube  17  (only one of which is shown in  FIG. 8 , but both in  FIG. 5 ), and then spaced electrically-conductive deposits or coatings  78  are made over each of the openings  76  so as to electrically contact, respectively, one of the internal wires  74 . For example, the electrically-conductive deposits can be silvered coatings. The electrically-conductive coatings  78  also extend along the outer surface of the tube  22  to form two longitudinally-spaced electrically-conductive bands  78  that are exposed on the outer surface of the electrode tube  22 . The arrangement is such that each of the external bands  78  forms an electrical contact to one of the internal wires  74 . It will be appreciated that two electrically-insulated bands are required for providing separate electrical connections to each of the active bipolar tips. If a unipolar electrode were involved, then only one band would be required if only one internal wire  74  were present, which would then be connected to the unipolar electrode, or if two internal wires  74  were still present, then both could be internally interconnected to the single unipolar electrode, in which case the same dual band system could be employed but only one need be connected externally. Thus, with the two band arrangement illustrated, unipolar and bipolar electrodes could be interchanged and used with the same handpiece when the plug  28  is plugged into the proper socket of the electrosurgical equipment. 
     The electrical connecting arrangement illustrated in  FIGS. 6 and 7  is preferred because it allows for easy interconnections and assembly of the handpiece, without the need for welding or soldering operations. The insulated electrical wire  26  from the external plug  28  is laid into a groove  80  after the ends  82 ,  84  have been stripped of its insulation. One end  82  is placed inside the bottom groove  60  (in  FIG. 6 ) which merges with the first annular external groove  68 , makes a quarter turn in the latter groove and re-enters into the part  48  through the radial hole  66 , runs axially forward inside the groove  64 , exits through a radial hole  66  and makes another quarter turn in the second annular external groove  68  forming an end external circular portion  86  which extends above the lower cap  48  and eventually will be bent or folded into the corresponding second annular external groove  68  of the upper cap  46  when assembled to the lower cap  48 . Similarly, the second end  84  is placed inside the upper groove  60  (in  FIG. 6 ) which merges with the third annular external groove  68 , makes a quarter turn in the latter groove and re-enters into the part  48  through the radial hole  66 , runs axially forward inside the groove  64 , exits through a radial hole  66  and makes in this case a full turn in the fourth or last annular external groove  68  forming an end external circular portion  88  which extends above the lower cap  48  and eventually will be bent or folded into the corresponding fourth annular external groove  68  of the upper cap  46  when assembled to the lower cap  48 . The result of this arrangement is the partial exposure inside the assembled two cap halves of two spaced longitudinally-extending bare wire sections that are exposed to the bore interior  96 . The first bare wire section  98  is connected to one of the 2-wire lead-in and the second bare wire  100  is connected to the second of the 2-wire lead-in. When the two cap parts are assembled, the bare wire sections remain exposed on the inside, and the assembly can be held together by addition of the end collar  58  and subsequent fusing if desired. 
     Now, when the electrode  18  is inserted axially along the aligned openings as shown in  FIG. 7 , the leading band  78  makes electrical contact with the longitudinally-extending wire section  100 , and the trailing band  78  makes electrical contact with the longitudinally-extending wire section  98 , thereby establishing a good electrical connection between the active bipolar tips  24  and the two wires of the lead-in conductor  26 . Any electrode with a similar single or dual band arrangement can be used with the handpiece of  FIG. 1 , so long as it is configured so that it fits within the axially aligned bores and is provided with an external electrically-conductive band located to contact the internally exposed wire sections  98 ,  100 . Note that, after assembly, the laterally-arranged stripped wire ends confined to their internal laterally spaced longitudinal grooves and longitudinally-spaced external annular or circumferentially-arranged grooves are completely electrically-insulated from one another producing internal (to the cap) longitudinally-spaced electrically-insulated wire sections  98 ,  100  which are easily contacted in a positive and reliable manner to the external bands on the removable or fixed electrode  18 . One of the advantages of the arrangement described is that winding of the bare wire ends inside and around the various groves in the lower cap part  48  fixes the wires in place while the upper cap  46  is placed over the assembled lower cap and wire and the units held together at least temporarily by looping the respective wire ends  86 ,  88  into the corresponding grooves of the upper cap  46 . 
     The assembly can be made permanent by force-fitting together of the parts or by using adhesives between the assembled parts. A preferred way is to slightly taper the various parts that telescope together, apply as by brushing to the eternal surface of the inner fitting part a suitable solvent for the plastic, and force the parts together. The solvent slightly dissolves a thin surface layer of the plastic and when the solvent evaporates, the two contacted parts are essentially fused together permanently. 
     As will be evident from  FIG. 2 , with the handle  12  removed, the two body parts  14 ,  16  separate. To complete the assembly, after the latter have been individually assembled, the spring  34  is inserted, and projecting part  36  assembled to the bore  32 , the spring is then compressed, and the handle  12  mounted across the two body parts by means of the bifurcated ends  102 ,  104  with their respective holes  106 ,  108  engaging the posts  110 ,  112  on opposite sides of the two body parts  14 ,  16 . 
       FIG. 5  shows just the electrode tube  18  alone. The right end is referenced at  114 , and  116  designates the extended active electrode with its bipolar tips  24  when the handle  12  is squeezed. The extended end  116  assumes a pre-bent shape or is constituted of memory metal, and when retracted slides smoothly back into the outer tube  18 . (not shown in  FIG. 5 )  FIG. 1  shows the assembled handpiece with a retracted electrode and  FIG. 3  shows the arrangement when the handle is squeezed shut to extend the electrode. The bipolar tips or active unipolar end can be composed of any electrically-conductive metal, such as tungsten, steel, silver or silver alloys. 
     As in the earlier applications for the bipolar handpiece, two electrically-insulated wires are passed through insulated compartments of a tube. For a unipolar handpiece, only a single wire may be necessary connected to a typical unipolar electrode such as a ball, point, rod, or loop, as examples. 
     As used herein, by “axial” is meant parallel to the long axis of the electrode (horizontal in  FIGS. 2 and 3 ). By “lateral” is meant transverse to the long axis of the electrode. 
     Once the surgeon has positioned the working end of the handpiece with respect to the tissue to be operated on, he or she then activates the electrosurgical apparatus causing a discharge of bipolar currents between the bare electrode loop ends  24  capable of causing ablation, shrinkage, or excision of tissue, or cauterization of a blood vessel in the usual way. Other usable mechanical or electrical structures following the teachings of the prior applications will be appreciated by those skilled in this art. As with the embodiments of the prior application, the insulating tube  18  will prevent accidental touching of patient tissue by the electrode sides, so that the bipolar discharge is localized to the spacing between the bare ends. 
     In all embodiments, the tubular housing  18  can be plastic, such as ABS or DELRIN, or of insulated relatively stiff metal that will not bend except where desired at the area of the openings  76 . For example, the tube outside diameter can be typically about 0.04–0.1 inches. For the application of shrinking herniated tissue via a cannula, the tubular housing is typically about 15–20 inches long. It will also be noted that the features set forth in commonly owned U.S. Pat. Nos. 6,652,514 and 6,712,813, namely incorporating the handpiece with the flexible tip of the invention into the intelligent operating-mode selection system of the earlier patent, and/or as a procedure-dedicated handpiece of the later patent, can also be readily implemented by those skilled in this art following the teachings of those patents. 
     The automatic retraction of the electrode is caused in the preferred embodiment by the internal compression spring  34 . Alternatively, the plastic handle can be configured such that it has built-in resilience which tends to return it to its open position shown in  FIG. 1 . As a further alternative, a resilient leaf or helical spring, for example, of metal or fiberglass, can be fitted inside of or between the handle sides to provide an outward bias force tending to maintain the handle sides in their open position. However, it is preferred that the handle itself be electrically-insulating to prevent any chance of an electric shock to the surgeon or the patient. 
     An important advantage of the construction described is its inexpensive construction and fabrication thus allowing handpiece disposability after one use. However, as explained above, the handpiece of the invention can also be reused if desired by appropriate sterilization after each use. 
     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.