US20030109875A1 - Open vessel sealing forceps with disposable electrodes - Google Patents

Abstract

A removable electrode assembly for use in combination with a forceps having opposing end effectors and a handle for effecting movement of the end effectors relative to one another. The electrode assembly includes a housing which is removably engageable with the forceps and a pair of electrodes which are attachable to a distal end of the housing. The electrodes are removably engageable with the end effectors of the forceps such that the electrodes reside in opposing relation relative to one another. The electrode assembly also includes a cover plate which is removably attachable to the housing and at least one stop member for controlling the distance the electrodes move relative to one another.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application claims priority to U.S. application Ser. No. 09/177,950 filed Oct. 23, 1998 by Randel A. Frazier et al., and to U.S. application Ser. No. 09/178,027 filed Oct. 23, 1998 by Philip Mark Tetzlaff et al., the entire contents of each of these applications are hereby incorporated by reference.[0001]
BACKGROUND
• The present disclosure relates to electrosurgical forceps used for open surgical procedures and/or laparoscopic surgical procedures. More particularly, the present disclosure relates to a bipolar forceps having a disposable electrode assembly for sealing, cauterizing, coagulating/desiccating and/or cutting vessels and vascular tissue.[0002]
TECHNICAL FIELD
• A hemostat or forceps is a simple plier-like tool which uses mechanical action between its jaws to constrict tissue and is commonly used in open surgical procedures to grasp, dissect and/or clamp tissue. Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, cut and/or seal tissue.[0003]
• By utilizing an electrosurgical forceps, a surgeon can either cauterize, coagulate/desiccate and/or cut tissue and/or simply reduce or slow bleeding, by controlling the intensity, frequency and duration of the electrosurgical energy applied to the tissue. Generally, the electrical configuration of electrosurgical forceps can be categorized in two classifications: 1) monopolar electrosurgical forceps; and 2) bipolar electrosurgical forceps.[0004]
• Monopolar forceps utilize one active electrode associated with the clamping end effector and a remote patient return electrode or pad which is attached externally to the patient. When the electrosurgical energy is applied, the energy travels from the active electrode, to the surgical site, through the patient and to the return electrode.[0005]
• Bipolar electrosurgical forceps utilize two generally opposing electrodes which are disposed on the inner opposing surfaces of end effectors and which are both electrically coupled to an electrosurgical generator. Each electrode is charged to a different electric potential. Since tissue is a conductor of electrical energy, when the effectors are utilized to clamp or grasp tissue therebetween, the electrical energy can be selectively transferred through the tissue.[0006]
• The process of coagulating small vessels is fundamentally different than vessel sealing. For the purposes herein the term coagulation is defined as a process of desiccating tissue wherein the tissue cells are ruptured and dried. Vessel sealing is defined as the process of liquefying the collagen in the tissue so that it cross-links and reforms into a fused mass. Thus, coagulation of small vessels is sufficient to close them, however, larger vessels need to be sealed to assure permanent closure.[0007]
• In order to effect a proper seal with larger vessels, two predominant mechanical parameters must be accurately controlled—the pressure applied to the vessel and the gap between the electrodes both of which affect thickness of the sealed vessel. More particularly, accurate application of the pressure is important to oppose the walls of the vessel, to reduce the tissue impedance to a low enough value that allows enough electrosurgical energy through the tissue, to overcome the forces of expansion during tissue heating and to contribute to the end tissue thickness which is an indication of a good seal. In some instances a fused vessel Wall is optimum between 0.001 and 0.006 inches. Below this range, the seal may shred or tear and above this range the lumens may not be properly or effectively sealed.[0008]
• Numerous bipolar electrosurgical forceps have been proposed in the past for various open surgical procedures. However, some of these designs may not provide uniformly reproducible pressure to the blood vessel and may result in an ineffective or non-uniform seal. For example, U.S. Pat. No. 2,176,479 to Willis, U.S. Pat. No. 4,005,714 to Hiltebrandt, U.S. Pat. Nos. 4,370,980, 4,552,143, 5,026,370 and 5,116,332 to Lottick, U.S. Pat. No. 5,443,463 to Stern et al., U.S. Pat. No. 5,484,436 to Eggers et al., all relate to electrosurgical instruments for coagulating, cutting and/or sealing vessels or tissue.[0009]
• These instruments rely on clamping pressure alone to procure proper sealing thickness and are not designed to take into account gap tolerances and/or parallelism and flatness requirements which are parameters which, if properly controlled, can assure a consistent and effective tissue seal. For example, it is known that it is difficult to adequately control thickness of the resulting sealed tissue by controlling clamping pressure alone for either of two reasons: 1) if too much force is applied, there is a possibility that the two poles will touch and energy will not be transferred through the tissue resulting in an ineffective seal; or 2) if too low a force is applied, a thicker less reliable seal is created.[0010]
• It has also been found that cleaning and sterilizing many of the prior art bipolar instruments is often impractical as electrodes and/or insulation can be damaged. More particularly, it is known that electrically insulative materials, such as plastics, can be damaged or compromised by repeated sterilization cycles.[0011]
• Thus, a need exists to develop a bipolar forceps which can seal vessels and tissue consistently and effectively and which will not be damaged by continued use and cleaning.[0012]
SUMMARY
• The present disclosure relates to a removable electrode assembly for use in combination with a mechanical forceps having opposed end effectors and a handle for controlling movement of the end effectors relative to one another. The electrode assembly includes a housing which is removably engageable with the mechanical forceps and a pair of electrodes which are attachable to a distal end of the housing. The electrodes are removably engageable with the end effectors of the mechanical forceps such that the electrodes reside in opposing relation relative to one another. Preferably, the electrode assembly can be employed with both open surgical procedures as well as laparoscopic surgical procedures.[0013]
• Preferably, the distal end of the housing is bifurcated forming two prongs and each of the electrodes is attached to each of the prongs. In one embodiment, the prongs are movable relative to one another to facilitate engagement of the electrodes with the end effectors of the mechanical forceps.[0014]
• Each electrode preferably includes an electrically conductive sealing surface and an insulating substrate. The substrate includes at least one mechanical interface for engaging a complimentary mechanical interface disposed on the corresponding end effector of the mechanical forceps. In one embodiment the electrodes include at least one guide pin and the corresponding end effector includes a complimentary aperture for receiving the guide pin.[0015]
• Preferably, the electrode assembly includes at least one stop member for controlling the distance between the opposing electrodes. In another embodiment of the present disclosure, the mechanical forceps includes at least one stop member for controlling the distance between the end effectors which, in turn, control the distance between the attached opposing electrodes.[0016]
• Another embodiment of the present disclosure includes a cover plate which is removably engageable with the housing member and the mechanical forceps are disposed between the housing and the cover plate when the bipolar forceps is assembled.[0017]
• Another embodiment includes a removable electrode assembly which includes a housing having at least one portion which is removably engageable with at least one portion of the forceps and a pair of electrodes attachable to a distal end of the housing. Preferably, the electrodes are removably engageable with the end effectors of the forceps such that the electrodes reside in opposing relation relative to one another. Preferably, the electrodes are electrically isolated from the handle.[0018]
• Another embodiment includes a bipolar forceps which includes a mechanical forceps having opposing end effectors and a handle for effecting movement of the end effectors relative to one another and an electrode assembly which removably engages the mechanical forceps. A pair of opposing electrodes are attached to a distal end of the electrode assembly and are removably engageable with one of the end effectors such that the electrodes reside in opposing relation relative to one another. Preferably, at least one stop member controls the distance between the opposing electrodes.[0019]
• Still yet another embodiment includes a bipolar electrosurgical instrument which includes a pair of first and second members each having an end effector attached to a distal end thereof and a handle attached to a proximal end thereof for effecting movement of the end effectors relative to one another. An electrode assembly is removably engageable with one of the first or second members and has a pair of electrodes which are removably engageable with the end effectors.[0020]
• Another embodiment includes a bipolar electrosurgical instrument having a pair of first and second members each having an end effector attached to a distal end thereof and a handle movable from a first position wherein the first and second members are disposed in spaced relation relative to one another to a second position wherein the members are closer relative to one another. A first electrode removably mounts to the first end effector and a second electrode removably mounts to the second end effector.[0021]
• Yet another embodiment includes a bipolar electrosurgical instrument having at least one stop member for maintaining a gap distance between the opposing electrodes, the gap distance being in the range of about 0.001 inches to about 0.006 inches.[0022]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a bipolar forceps according to the present disclosure;[0023]
• FIG. 2 is an enlarged, perspective view of a distal end of the bipolar forceps shown in. FIG. 1;[0024]
• FIG. 3 is a perspective view with parts separated of the forceps shown in FIG. 1;[0025]
• FIG. 4 is an enlarged, side view of a disposable electrode assembly of FIG. 1 shown without a cover plate;[0026]
• FIG. 5 is an enlarged, perspective view of a distal end of the disposable electrode assembly of FIG. 4;[0027]
• FIG. 6 is a perspective view with parts separated of an upper electrode of the disposable electrode assembly of FIG. 5;[0028]
• FIG. 7 is a perspective view with parts separated of a lower electrode of the disposable electrode assembly of FIG. 5;[0029]
• FIG. 8 is a perspective view of the forceps of the present disclosure showing the operative motion of the forceps to effect sealing of a tubular vessel;[0030]
• FIG. 9 is an enlarged, partial perspective view of a sealing site of a tubular vessel;[0031]
• FIG. 10 is a longitudinal cross-section of the sealing site taken along line[0032]10-10 of FIG. 9;
• FIG. 11 is a longitudinal cross-section of the sealing site of FIG. 9 after separation of the tubular vessel;[0033]
• FIG. 12 is a perspective view of another embodiment of the present disclosure;[0034]
• FIG. 13 is an exploded view of the embodiment of FIG. 12; and[0035]
• FIG. 14 is an enlarged exploded view of a working end of the embodiment of FIGS. 12 and 13.[0036]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Referring now to FIGS.[0037]1-3, abipolar forceps10 for use with open and/or laparoscopic surgical procedures includes amechanical forceps20 and anelectrode assembly21. In the drawings and in the description which follows, the term “proximal”, as is traditional, will refer to the end of theforceps10 which is closer to the user, while the term “distal” will refer to the end which is further from the user.
• [0038]Mechanical forceps20 includes first andsecond members9 and11 which each have an elongatedshaft12 and14, respectively.Shafts12 and14 each include aproximal end13 and15 and adistal end17 and19, respectively. Eachproximal end13,15 of eachshaft portion12,14 includes ahandle member16 and18 attached thereto to allow a user to effect movement of at least one of theshaft portions12 and14 relative to one another. Extending from thedistal end17 and19 of eachshaft portion12 and14 areend effectors22 and24, respectively. Theend effectors22 and24 are movable relative to one another in response to movement ofhandle members16 and18.
• Preferably,[0039]shaft portions12 and14 are affixed to one another at a point proximate theend effectors22 and24 about apivot25 such that movement of thehandles16 and18 impart movement of theend effectors22 and24 from an open position wherein theend effectors22 and24 are disposed in spaced relation relative to one another to a clamping or closed position wherein theend effectors22 and24 cooperate to grasp atubular vessel150 therebetween (see FIG. 8). It is envisioned thatpivot25 has a large surface area to resist twisting and movement offorceps10 during operation. Clearly, theforceps10 can be designed such that movement of one or both of thehandles16 and18 will only cause one of the end effectors, e.g.,22, to move with respect to the other end effector, e.g.,24.
• As best seen in FIG. 3,[0040]end effector24 includes an upper orfirst jaw member44 which has an inner facingsurface45 and a plurality of mechanical interfaces disposed thereon which are dimensioned to releasable engage a portion of adisposable electrode assembly21 which will be described in greater detail below. Preferably, the mechanical interfaces includesockets41 which are disposed at least partially through inner facingsurface45 ofjaw member44 and which are dimensioned to receive a complimentary detent attached toupper electrode120 of thedisposable electrode assembly21. While the term socket is used herein, it is contemplated that either a male or female mechanical interface may be used onjaw member44 with a mating mechanical interface disposed on thedisposable electrode assembly21.
• In some cases, it may be preferable to manufacture[0041]mechanical interfaces41 along another side ofjaw member44 to engage a complimentary mechanical interface of thedisposable electrode assembly21 in a different manner, e.g., from the side.Jaw member44 also includes anaperture67 disposed at least partially throughinner face45 ofend effector24 which is dimensioned to receive acomplimentary guide pin124 disposed onelectrode120 of thedisposable electrode assembly21.
• [0042]End effector22 includes a second orlower jaw member42 which has an inner facingsurface47 which opposes inner facingsurface45. Preferably,jaw members45 and47 are dimensioned generally symmetrically, however, in some cases it may be preferable to manufacture the twojaw members42 and44 asymmetrically depending upon a particular purpose. In much the same fashion as described above with respect tojaw member44,jaw member42 also includes a plurality of mechanical interfaces orsockets43 disposed thereon which are dimensioned to releasable engage a complimentary portion disposed on anelectrode110 of thedisposable electrode assembly21 as described below. Likewise,jaw member42 also includes an aperture65 disposed at least partially throughinner face47 which is dimensioned to receive a complimentary guide pin126 (see FIG. 4) disposed onelectrode110 of thedisposable electrode assembly21.
• Preferably,[0043]shaft members12 and14 of themechanical forceps20 are designed to transmit a particular desired force to the opposing inner facing surfaces47 and45 of the of thejaw members22 and24, respectively, when clamped. In particular, since theshaft members12 and14 effectively act together in a spring-like manner (i.e., bending that behaves like a spring), the length, width, height and deflection of theshaft members12 and14 will directly effect the overall transmitted force imposed on opposingjaw members42 and44. Preferably,jaw members22 and24 are more rigid than theshaft members12 and14 and the strain energy stored in theshaft members12 and14 provides a constant closure force between thejaw members42 and44.
• Each[0044]shaft member12 and14 also includes aratchet portion32 and34. Preferably, each ratchet, e.g.,32, extends from theproximal end13 of itsrespective shaft member12 towards theother ratchet34 in a generally vertically aligned manner such that the inner facing surfaces of eachratchet32 and34 abut one another when theend effectors22 and24 are moved from the open position to the closed position. Eachratchet32 and34 includes a plurality offlanges31 and33, respectively, which project from the inner facing surface of eachratchet32 and34 such that theratchets32 and34 can interlock in at least one position. In the embodiment shown in FIG. 1, theratchets32 and34 interlock at several different positions. Preferably, each ratchet position holds a specific, i.e., constant, strain energy in theshaft members12 and14 which, in turn, transmit a specific force to theend effectors22 and24 and, thus, theelectrodes120 and110. A design without a ratchet system or similar system would require the user to hold thejaw members42 and44 together by applying constant force to thehandles16 and18 which may yield inconsistent results.
• In some cases it may be preferable to include other mechanisms to control and/or limit the movement of the[0045]jaw members42 and44 relative to one another. For example, a ratchet and pawl system could be utilized to segment the movement of the two handles into discrete units which will, in turn, impart discrete movement to thejaw members42 and44 relative to one another.
• Preferably, at least one of the shaft members, e.g.,[0046]14, includes atang99 which facilitates manipulation of theforceps20 during surgical conditions as well as facilitates attachment ofelectrode assembly21 onmechanical forceps20 as will be described in greater detail below.
• As best seen in FIGS. 2, 3 and[0047]5,disposable electrode assembly21 is designed to work in combination withmechanical forceps20. Preferably,electrode assembly21 includeshousing71 which has aproximal end77, adistal end76 and anelongated shaft plate78 disposed therebetween. Ahandle plate72 is disposed near theproximal end77 ofhousing71 and is sufficiently dimensioned to releasably engage and/or encompasshandle18 ofmechanical forceps20. Likewise,shaft plate78 is dimensioned to encompass and/or releasably engageshaft14 andpivot plate74 disposed near thedistal end76 ofhousing71 is dimensioned to encompasspivot25 and at least a portion ofdistal end19 ofmechanical forceps20. It is contemplated that theelectrode assembly21 can be manufactured to engage either the first orsecond members9 and11 of themechanical forceps20 and theirrespective component parts12,16 or14,18, respectively.
• In the embodiment shown in FIG. 2, handle[0048]18,shaft14,pivot25 and a portion ofdistal end19 are all dimensioned to fit into corresponding channels located inhousing71. For example, achannel139 is dimensioned to receivehandle18, achannel137 is dimensioned to receiveshaft14 and achannel133 is dimensioned to receivepivot25 and a portion ofdistal end19.
• [0049]Electrode assembly21 also includes acover plate80 which is also designed to encompass and/or engagemechanical forceps20 in a similar manner as described with respect to thehousing71. More particularly,cover plate80 includes aproximal end85, adistal end86 and anelongated shaft plate88 disposed therebetween. Ahandle plate82 is disposed near theproximal end85 and is preferably dimensioned to releasable engage and/or encompasshandle18 ofmechanical forceps20. Likewise,shaft plate88 is dimensioned to encompass and/or releasable engageshaft14 and apivot plate94 disposed neardistal end86 is designed to encompasspivot25 anddistal end19 ofmechanical forceps20. Preferably, handle18,shaft14,pivot25 anddistal end19 are all dimensioned to fit into corresponding channels (not shown) located incover plate80 in a similar manner as described above with respect to thehousing71.
• As best seen with respect to FIGS. 3 and 4,[0050]housing71 andcover plate80 are designed to engage one another overfirst member11 ofmechanical forceps20 such thatfirst member11 and its respective component parts, e.g., handle18,shaft14,distal end19 andpivot25, are disposed therebetween. Preferably,housing71 andcover plate80 include a plurality of mechanical interfaces disposed at various positions along the interior ofhousing71 andcover plate80 to effect mechanical engagement with one another. More particularly, a plurality ofsockets73 are disposedproximate handle plate72,shaft plate78 andpivot plate74 ofhousing71 and are dimensioned to releasably engage a corresponding plurality ofdetents83 extending fromcover plate80. It is envisioned that either male or female mechanical interfaces or a combination of mechanical interfaces may be disposed withinhousing71 with mating mechanical interfaces disposed on or withincover plate80.
• As best seen with respect to FIGS.[0051]5-7, thedistal end76 ofelectrode assembly21 is bifurcated such that two prong-like members103 and105 extend outwardly therefrom to support anelectrode110 and120, respectively. More particularly,electrode120 is affixed at anend90 ofprong105 andelectrode110 is affixed at anend91 ofprong103. It is envisioned that theelectrodes110 and120 can be affixed to theends91 and90 in any known manner such as, e.g., frictional or snap-fit engagement.
• A pair of[0052]wires60 and62 are connected to theelectrodes120 and110, respectively, as best seen in FIGS. 4 and 5. Preferably,wires60 and62 are bundled together and form awire bundle28 which runs from a terminal connector30 (see FIG. 3), to theproximal end77 ofhousing71, along the interior ofhousing71, todistal end76.Wire bundle28 is separated intowires60 and62 proximatedistal end76 and thewires60 and62 are connected to eachelectrode120 and110, respectively. In some cases it may be preferable to capture thewires60 and62 or thewire bundle28 at various pinch points along the inner cavity of theelectrode assembly21 and enclosing thewires60 and62 withinelectrode assembly21 by attaching thecover plate80.
• This arrangement of[0053]wires60 and62 is designed to be convenient to the user so that there is little interference with the manipulation ofbipolar forceps10. As mentioned above, the proximal end of thewire bundle28 is connected to aterminal connector30, however, in some cases it may be preferable to extendwires60 and62 to an electrosurgical generator (not shown). Alternatively,wires60 and62 can remain separated and extend along the first andsecond members9 and11.
• As best seen in FIG. 6,[0054]electrode120 includes an electricallyconductive seal surface126 and an electricallyinsulative substrate121 which are attached to one another by snap-fit engagement or some other method of assembly, e.g.,substrate121 is overmolded to capture the electricallyconductive seal surface126. Preferably,substrate121 is made from an injection molded plastic material and is shaped to mechanically engage a correspondingsocket41 located injaw member44 ofend effector24. Thesubstrate121 not only insulates the electric current but it also alignselectrode120 both of which contribute to the seal quality and consistency. For example, by overmolding theconductive surface126 to thesubstrate121, the alignment and thickness of theelectrode120 can be controlled.
• Preferably,[0055]substrate121 includes a plurality ofbifurcated detents122 which are shaped to, compress during insertion intosockets41 and expand and releasably engagesockets41 after insertion. It is envisioned that snap-fit engagement of theelectrode120 and thejaw member44 will accommodate a broader range of manufacturing tolerances.Substrate121 also includes an alignment orguide pin124 which is dimensioned to engageaperture67 ofjaw member44.
• [0056]Conductive seal surface126 includes anwire crimp145 designed to engage thedistal end90 ofprong105 ofelectrode assembly21 and electrically engage a corresponding wire connector affixed to wire60 located within electrode assembly.Seal surface126 also includes an opposingface125 which is designed to conduct an electrosurgical current to a tubular vessel ortissue150 when it is held thereagainst.
• [0057]Electrode110 includes similar elements for insulating and conducting electrosurgical current totissue150. More particularly,electrode110 includes an electricallyconductive seal surface116 and an electricallyinsulative substrate111 which are attached to one another by snap-fit engagement or some other method of assembly.Substrate111 includes a plurality ofbifurcated detents112 and an alignment pin126 (see FIG. 4) which are dimensioned to engage a corresponding plurality ofsockets43 and aperture65 located injaw member42.Conductive seal surface116 includes anextension155 having awire crimp119 which engages thedistal end91 ofprong103 and electrically engages a corresponding wire connector affixed to wire62 located inhousing71.Seal surface116 also includes an opposingface115 which conducts an electrosurgical current to a tubular vessel ortissue150 when it is held thereagainst. Alternatively,electrodes110 and/or120 can be formed as one piece and include similar components for insulating and conducting electrical energy.
• As best seen in FIG. 7,[0058]substrate111 also includes anextension108 and astop member106 which is designed to engagecorresponding extension155 and aninterface107 located onconductive seal116. To assembleelectrode110,stop member106 andextension108 are overmolded ontointerface107 andextension155 ofconductive seal116. After assembly,wire crimp119 is then inserted intoend91 ofprong member103 and connected to wire62.
• It is known that as the tissue is compressed and electrosurgical energy is applied to the tissue, the impedance of the tissue decreases as the moisture level decreases. As a result, two mechanical factors play an important role in determining seal thickness and effectiveness, i.e., the pressure applied between opposing faces[0059]47 and45 and the gap distance between the opposingelectrodes110 and120 (see FIG. 5).Jaw members42 and44 are configured to provide for the opposingelectrodes110 and120 to be in a desired gap range (e.g., 0.001 and 0.006 inches) at the end of the tissue sealing process (See FIG. 8). The material conditions and components relating to the assembly of theelectrode assembly21 and themechanical forceps20 are configured to fall within specific manufacturing tolerances to assure that the gap between electrodes will not vary outside the desired range.
• It is also known that tissue thickness is very difficult to control by force alone, i.e., too much force and the two poles would touch and the little energy would travel through the tissue resulting in a bad seal or too little force and the seal would be too thick. Applying the correct force is important for other reasons: to oppose the vessel lumens; reduce the tissue impedance to a low enough value that allows enough current through the tissue; and to overcome the forces of expansion during tissue heating in addition to contributing towards creating the required end tissue thickness which is an indication of a good seal.[0060]
• It is also known that the size of the gap effects the tissue seal. For example, if a gap is too great, i.e., the jaws do not compress the tissue enough, the tissue does not properly liquefy the collagen for effective sealing. If, on the other hand, the gap is too small, i.e., the jaws compress the tissue too much, the electrosurgical energy effectively severs the tissue which is also undesirous. It has been found that in order to effectively seal tissue and overcome the shortcomings described above, the gap distance (range)[0061]151 (See FIG. 8) between the opposingelectrodes110 and120 is preferably between about 0.001 inches to about 0.006 inches and more preferably, between about 0.002 inches to about 0.005 inches.
• In order to assure that the desired gap range is achieved after assembly and that the correct force is applied to seal the tissue,[0062]substrate111 includes at least one stop member,106, which is designed to restrict and/or regulate movement of the twoelectrodes110 and120 relative to one another. Preferably,forceps20 also includes at least one stop member, e.g.,101 (see FIG. 3), for restricting and/or regulating the distance betweenend effectors22 and24 and/or the closure force applied between opposing inner facing surfaces47 and45 ofend effectors22 and24 which will, in turn, regulate the distance betweenelectrodes110 and120. Sincestop106 is part of thedisposable electrode assembly21, this stop has the added benefit of being dependent on the material of thedisposable electrode assembly21. Preferably, a “step” stop is utilized due to its ease of manufacture and simplicity.
• It is contemplated that the stop member can be positioned at various points along the disposable electrode assembly to achieve the aforedescribed desired gap range and/or the stop member can be positioned on other parts of the instrument, e.g., handles[0063]16,18,jaws42,44, and/orshafts12,14.
• Preferably, the seal surfaces[0064]115 and125 are relatively flat to avoid current concentrations at sharp edges and to avoid arcing between high points. In addition and due to the reaction force of thetissue150 when engaged,jaw members42 and44 are preferably manufactured to resist bending. For example and as best seen in FIG. 3, thejaw members42 and44 and the correspondingelectrodes110 and120 are preferably tapered along width “W” which is advantageous for two reasons: 1) the taper will apply constant pressure for a constant tissue thickness at parallel; 2) the thicker proximal portion of the electrode, e.g.,110, will resist bending due to the reaction force of thetissue150. The tapered shape of the electrode, e.g.,110, is determined by calculating the mechanical advantage variation from the distal to proximal end of theelectrode110 and adjusting the width of theelectrode110 accordingly.
• Preferably, at least one of the prong members, e.g.,[0065]105, is resilient or includes aflex relief portion53 which permits movement of the twoprong members105 and103 and, thus, the twoelectrodes120 and110, relative to one another. As seen best in FIG. 3, theelectrode assembly21 is removably attached to themechanical forceps20 by initially movingprong105 towardsprong103 by bendingprong105 atflex relief portion53. Theelectrodes110 and120 are then slid between opposingjaw members42 and44 in their open position such thatdetents112 and122 and guidepins126 and124, respectively, are each disposed in alignment with each correspondingsocket43 and41 oraperture65 and67, respectively.Housing71 is also positioned accordingly such thatshaft14, handle18 andpivot25 are all positioned proximate theircorresponding channels137,139 and133 located withinhousing71.
• When[0066]flex relief portion53 is released, eachelectrode110 and120 is engaged withjaw member42 and44, respectively, i.e.,detents112,122 engagesockets43,41, andhousing71 is engaged withmechanical forceps20. Thecover plate80 is then attached tohousing71 in the manner described above. Thebipolar forceps10 is now ready for operation.
• In one embodiment, the[0067]electrode assembly21 is attached to themechanical forceps20 in a different manner. For example and as best illustrated in FIG. 3, theelectrode assembly21 can be engaged with themechanical forceps20 in the following four-step manner: 1)electrode assembly21 andcover plate80 are pivoted backward such thattang99 engages aslot100 inelectrode assembly21; 2)electrode assembly21 andcover plate80 are then pivoted forward to engageshaft14 ofmechanical forceps20 therebetween; 3)detents112 ofelectrode110 are then engaged withsockets43 ofjaw member22; and 4)detents122 ofelectrode120 are engaged withsockets41 ofjaw member24.
• FIG. 8 shows the[0068]bipolar forceps10 during use wherein thehandle members16 and18 are moved closer to one another to apply clamping force to thetubular tissue150 to effect aseal152 as shown in FIGS. 9 and 10. Once sealed, thetubular vessel150 can be cut alongseal152 to separate thetissue150 andform gap154 therebetween as shown in FIG. 11.
• After the[0069]bipolar forceps10 is used or if theelectrode assembly21 is damaged, theelectrode assembly21 can be easily removed and/or replaced by reversing the above attachment procedure and anew electrode assembly21 can be engaged with themechanical forceps20 in the same manner. For example, theelectrode assembly21 can be disengaged from themechanical forceps20 in the following four-step manner: 1) thedetents122 ofelectrode120 are disengaged from thesockets41 ofjaw member24; 2) thedetents112 ofelectrode110 are disengaged from thesockets43 ofjaw member22; 3) theelectrode assembly21 andcover plate80 are disengaged fromshaft14 ofmechanical forceps20; and 4) theelectrode assembly21 andcover plate80 are pivoted such thattang99 disengages fromslot100 inelectrode assembly21.
• It is envisioned that by making the[0070]electrode assembly21 disposable, theelectrode assembly21 is less likely to become damaged since it is only intended for a single use and, therefore, does not require cleaning or sterilization. As a result, the functionality and consistency of the vital sealing components, e.g., theconductive surface126,116 and insulatingsurface121,111 will assure a uniform and quality seal.
• FIGS.[0071]12-14 show another embodiment of the present disclosure for use with endoscopic surgical procedures and includes a bipolar forceps210 having adrive rod assembly211 coupled to ahandle assembly218. Thedrive rod assembly211 includes an elongatedhollow shaft portion212 having aproximal end216 and adistal end214. Anend effector assembly222 is attached to thedistal end214 ofshaft212 and includes a pair of opposingjaw members280 and282. Preferably, handleassembly218 is attached to theproximal end216 ofshaft212 and includes anactivator220 for imparting movement of thejaw members280 and282 from an open position wherein thejaw members280 and282 are disposed in spaced relation relative to one another, to a clamping or closed position wherein thejaw members280 and282 cooperate to grasptissue150 therebetween.
• As best seen in FIG. 13,[0072]activator220 includes amovable handle226 having anaperture234 defined therein for receiving at least one of the operator's fingers and a fixed handle228 having anaperture232 defined therein for receiving an operator's thumb.Movable handle226 is selectively moveable from a first position relative to fixed handle228 to a second position in closer proximity to the fixed handle228 to closejaw members280 and282. Preferably, fixed handle228 includes achannel227 which extends proximally for receiving aratchet230 which is coupled tomovable handle226. This structure allows for progressive closure ofend effector assembly222 as well as locking engagement of opposingjaw members280 and282. In some cases it may be preferable to include other mechanisms to control and/or limit the movement ofhandle226 relative to handle228 such as, e.g., hydraulic, semi-hydraulic and/or gearing systems.
• Fixed handle[0073]228 includes arotating assembly223 for controlling the rotational movement ofend effector assembly222 about a longitudinal axis “A” of theelongated shaft212. Preferably, rotatingassembly223 includes upper andlower knob portions224aand224b, respectively, which releasably engage one another about agear252 which is attached toshaft212. A pair ofhandle sections228aand2228bengage one another by way of a plurality of mechanical interfaces to form fixed handle228. As best seen in FIG. 13, eachhandle section228aand228bis generally hollow such that acavity250 is formed therein for housing various internal components which make up the forceps210. For example,cavity250 houses aPC board258 which controls the electrosurgical energy being transmitted from an electrosurgical generator (not shown) to eachjaw member280 and282. More particularly, electrosurgical energy is generated from an electrosurgical generator and transmitted to the PC board bycable260 which attached through awire port229 disposed in the proximal end ofhandle assembly218. ThePC board258 converts the electrosurgical energy from the generator into two different electrical potentials which are transmitted to eachjaw member280 and282 by a separateterminal clip264band264a, respectively, which will be explained in more detail below with respect to FIG. 14.
• Referring to FIG. 14,[0074]rod assembly211 includes adrive rod270 which has aproximal end271 and adistal end272. Apiston238 is attached to theproximal end271 ofdrive rod270 and includes a generally roundedhead portion239 and anotch241 located between thehead portion239 and the proximal end ofpiston238. Preferably, clevisflanges249aand249bofarm240 are dimensioned to receivehead239 therebetween whenarm240 is assembled betweenhandle sections228aand228b(see FIG. 6). Movement of thehandle226 towards fixed handle228 imparts pivotal movement of theupper end245 ofarm240 at apivot point255 which, in turn, imparts movement of thepiston238 from a first position wherein thepiston238 is disposed further fromend effector assembly222 to a second position whereinpiston238 is in closer proximity to endeffector assembly222. As explained in greater detail below, movement of thepiston238 between first and second positions imparts linear movement to driverod270 which, in turn, movesjaw members280 and282 toward and away from each other.
• Seating the generally rounded[0075]head239 betweenclevis flanges249aand249benables the user to utilize therotating assembly223 effectively without interfering with the linear movement of thepiston238.
• The[0076]end effector assembly222 includesfirst jaw280,second jaw282 and an electrically insulatingyoke284 disposed therebetween. Preferably,jaw member280 andjaw member282 are movable from an open position to a closed position by movement of thehandle assembly218 as described above. It is contemplated that either both or one of thejaw members280 and282 can be movable relative to one another.First jaw member280 has afirst flange281 which extends therefrom and acam slot86 located therethrough. Likewise,second jaw282 has asecond flange283 which extends therefrom and acam slot288 located therethrough.
• The[0077]end effector assembly222 also includes anouter nose portion294 and aninner nose portion296 which engagejaw members282 and280, respectively. Afirst pivot305 is located onouter nose portion294 and is dimensioned to engage acorresponding pivot hole289 located onflange283. Asecond pivot303 is located oninner nose portion296 and is dimensioned to engage acorresponding pivot hole287 located onflange281. The center of rotation forfirst jaw member280 is at afirst pivot hole287 and the center of rotation forsecond jaw member282 is at asecond pivot hole289. Preferably, eachnose portion294 and296 is made from an electrically conductive material and transmits electrosurgical energy to arespective jaw member282 and280 as described in more detail below.
• As mentioned above with respect to FIG. 13, electrosurgical energy is transmitted from the electrosurgical generator to an[0078]connector assembly315 which includes thePC board258 which converts the energy into first and second poles. A pair ofterminal clips264aand264bare connected toPC board258 and transfer the first and second poles of alternating potential, respectively, to thedrive rod assembly211. Clip264aconnects toshaft212 and conducts the first pole tojaw member282 andclip264bconnects topiston238 which is, in turn, connected to driverod270. The second pole is conducted alongdrive rod270 tojaw member280. Both thedrive rod270 and theshaft212 are made from an electrically conductive material and preferably aninsulation sleeve275 is disposed betweendrive rod270 andshaft212 to prevent the forceps210 from short circuiting.
• As best seen in FIG. 14, the[0079]inner nose portion296 is electrically connected withdrive rod270 and theouter nose portion294 is electrically connected toshaft212. The inner andouter nose portions296 and294capture yoke284 along withflanges283 and281.Yoke284 moves axially along axis “A” in a space between inner andouter portions296 and294 and aspacer stake319 maintains the separation of thenose portions296 and294 at their distal ends.Stake319 is dimensioned to engage and lock the inner andouter nose portions296 and294 together, which, in turn locksjaw members280 and282 atopyoke284. In some cases it may be preferable todimension stake319 such thatstake319 acts as a stop member and controls the gap distance between the opposingjaw members280 and282 relative to one another. In this case,stake319 is formed from an electrically insulative material such as plastic. Thenose portions294 and296 provide lateral support for theflanges281 and283 and help ensure thatdetents290 and292 remain withincam slots286 and288, respectively.
• [0080]End effector assembly222 also includes aninner insulator302 and anouter insulator300 for maintaining electrical insulation between poles.Outer insulator300 insulatesouter nose portion294 frominner nose portion296 and driverod270 which conduct the second pole of electrical energy.Inner insulator302 insulatesinner nose portion296 fromouter nose portion294 andshaft212 which conduct the first pole of electrical energy. In this manner,outer nose portion294 can provide electrical continuity betweenshaft212 andjaw member282, whileinner nose portion296 can provide electrical continuity betweendrive rod270 andjaw member280.
• Preferably, a[0081]spring contact298 is utilized to maintain the electrical connection betweendrive rod270 andinner nose portion296 during axial motion of thedrive rod270. A donut-shapedspacer308 can also be utilized to assure linear motion of thedrive rod270 withinsleeve275 and to prevent accidental short circuiting of the forceps210.
• Referring back to FIG. 14,[0082]yoke284 is preferably formed from an electrically insulative material such as plastic. Afirst side291 ofyoke284 facesfirst flange281 and asecond side293 ofyoke284 facessecond flange283. When yoke84 is positioned betweenflanges281 and283,yoke284 electrically insulatesfirst jaw member80 fromsecond jaw member282. In this manner, bipolar electrosurgical current can be conducted through tissue350 which is grasped betweenjaws280 and282 withoutflanges281 and283 short circuiting.
• In order to achieve a desired gap range (e.g., about 0.001 to about 0.006 inches) and apply a desired force to seal the tissue, at least one[0083]jaw member280 and/or282 includes astop member339 which limits the movement of the two opposingjaw members280 and282 relative to one another. As explained above, in some cases it may be preferable todimension stake319 such that it acts like a stop member and limits the movement of the two opposingjaw members280 and282 relative to one another. Preferably,stop member339 and/orstake319 is made from an insulative material and is dimensioned to limit opposing movement of thejaw members280 and282 to within the above gap range.
• From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the present disclosure. For example, although it is preferable that[0084]electrodes110 and120 meet in parallel opposition, and, therefore, meet on the same plane, in some cases it may be preferable to slightly bias theelectrodes110 and120 to meet each other at a distal end such that additional closure force on thehandles16 and18 is required to deflect the electrodes in the same plane.
• Although it is preferable to vertically align[0085]electrodes110 and120, in some cases it may be preferable to offset the opposingelectrodes110 and120 relative to one another either longitudinally or transversally to suit a particular purpose.
• Although it is preferable that the[0086]electrode assembly21 includehousing71 andcover plate80 to engagemechanical forceps20 therebetween, in some cases it may be preferable to manufacture thedisposable electrode assembly21 such that only one piece, e.g.,housing71 is required to engagemechanical forceps20.
• While only one embodiment of the disclosure has been described, 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 a preferred embodiment. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.[0087]

Claims (34)

What is claimed is:

1. A removable electrode assembly for use with a forceps having opposing end effectors and a handle for effecting relative movement of the end effectors with respect to one another, the electrode assembly comprising:

a housing having at least one portion which is removably engageable with at least a portion of the forceps;

a pair of electrodes attachable to a distal end of the housing, the electrodes being removably engageable with the end effectors of the forceps such that the electrodes are disposed in opposing relation to one another; and

at least one stop member for controlling the distance between the opposing electrodes.

2. A removable electrode assembly according toclaim 1 wherein each of the electrodes includes an electrically conductive sealing surface and an insulating substrate.

3. A removable electrode assembly according toclaim 2 wherein the stop member is attached to the insulating substrate.

4. A removable electrode assembly according toclaim 1 wherein the distal end of the housing is bifurcated forming two prongs and each of the electrodes is attached to one of the prongs.

5. A removable electrode assembly according toclaim 4 wherein the prongs of the housing are movable relative to one another to facilitate engagement of the electrodes with the end effectors of the forceps.

6. A removable electrode assembly according toclaim 5 wherein the insulating substrate of each of the electrodes includes at least one mechanical interface for engaging a complimentary mechanical interface disposed on the corresponding end effector of the forceps.

7. A removable electrode assembly according toclaim 6 wherein the mechanical interface of at least one of the substrates includes at least one detent and the mechanical interface of the corresponding end effector includes at least one complimentary socket for receiving the detent.

8. A removable electrode assembly according toclaim 6 wherein the substrate of at least one of the electrodes includes at least one guide pin and the corresponding end effector includes at least one complimentary aperture for receiving the guide pin.

9. A removable electrode assembly according toclaim 1 wherein the stop member is attached to at least one of the end effectors.

10. A removable electrode assembly according toclaim 1 wherein the stop member is attached to at least one of the electrodes.

11. A removable electrode assembly according toclaim 1 wherein the electrodes are tapered.

12. A removable electrode assembly according toclaim 1 wherein each of the electrodes includes an electrical connector for coupling to a wire.

13. A removable electrode assembly according toclaim 1 wherein the housing is removably engageable with the handle of the forceps.

14. A removable electrode assembly according toclaim 1 further comprising a cover plate which is removably engageable with the housing.

15. A removable electrode assembly according toclaim 14 wherein both the housing and the cover plate are engageable with the forceps.

16. A removable electrode assembly according toclaim 15 wherein the forceps are disposed between the housing and the cover plate.

17. A removable electrode assembly according toclaim 1 wherein the housing includes a bifurcated distal end which forms two prongs and each electrode is removably attachable to one of the prongs.

18. A removable electrode assembly according toclaim 17 wherein the prongs of the housing are movable relative to one another to facilitate engagement of the electrodes with the end effectors of the forceps.

19. A removable electrode assembly according toclaim 1 further comprising at least one ratchet which engages at least one complementary mechanical interface to maintain a desired closure force between opposing electrodes.

20. A removable electrode assembly according toclaim 1 further comprising a pair of opposing ratchets which interlock in at least one position for maintaining a desired closure force between opposing electrodes.

21. A removable electrode assembly for use with a forceps having opposing end effectors and a handle for effecting relative movement of the end effectors with respect to one another, the electrode assembly comprising:

a housing having a portion which is removably engageable with a portion of the forceps; and

a pair of electrodes attachable to a distal end of the housing, the electrodes being removably engageable with the end effectors of the forceps such that the electrodes are disposed in opposing relation to one another.

22. A removable electrode assembly according toclaim 21 wherein the distal end of the housing is bifurcated forming two prongs and each of the electrodes is removably engageable with one of the prongs.

23. A removable electrode assembly according toclaim 22 wherein the prongs are movable relative to one another to facilitate engagement of the electrodes with the end effectors of the forceps.

24. A removable electrode assembly according toclaim 21 wherein the electrodes are electrically isolated from the handle.

25. A bipolar electrosurgical instrument, comprising:

a forceps having opposing end effectors and a handle for effecting relative movement of the end effectors with respect to one another, an electrode assembly removably attachable to the forceps, the electrode assembly including a pair of opposing electrodes attached to a distal end thereof, each of the electrodes being removably engageable with one of the end effectors such that the electrodes reside in opposing relation to one another, and at least one stop member for controlling the distance between the opposing electrodes.

26. A bipolar electrosurgical instrument comprising:

a pair of first and second members each having an end effector extending from a distal end thereof and a handle attached to a proximal end thereof for effecting relative movement of the end effectors with respect to one another; and

an electrode assembly which is removably engageable with the first member, the electrode assembly having a pair of electrodes, each electrode being removably engageable with one of the end effectors.

27. A bipolar electrosurgical instrument according toclaim 26 wherein the electrode assembly is bifurcated such that two prong-like members extend outwardly to support an electrode which is removably engaged with one of the end effectors.

28. A bipolar electrosurgical instrument comprising:

a pair of first and second members each having an end effector extending from a distal end thereof and a handle movable from a first position wherein the first and second members are disposed in spaced relation relative to one another to a second position wherein the members are closer relative to one another; and

a first electrode removably mounted to the first end effector and a second electrode removably mounted to the second end effector.

29. A bipolar electrosurgical instrument for sealing vessels, comprising:

first and second opposing end effectors, each end effector has an inner surface and an outer surface;

a handle disposed proximal of the first and second end effectors, the handle being movable from a first position wherein the first and second end effectors are disposed in spaced relation to one another to a second position wherein the end effectors are closer relative to one another such that the end effectors hold tissue therebetween for application of electrosurgical energy, the handle including at least one gripping portion to be gripped by a user to move the handle between the first position and the second position;

a first electrode disposed on the first end effector and a second electrode disposed on the second end effector such that movement of the handle from the first position to the second position results in the first and second electrodes being closer relative to each other, the electrodes residing in substantially opposing relation to one another and each electrode having a tissue contacting surface to engage tissue between the tissue contacting surfaces of the first and second electrodes and to enable the supply of electrosurgical energy to the tissue engaged therebetween to effect sealing;

a connector for electrically connecting the first and second electrodes to a source for supplying electrosurgical energy to each of the electrodes such that one of the electrodes has a first electrical potential and the other electrode has a second electrical potential such that the substantially opposing electrodes are capable of conducting bipolar energy through tissue held therebetween; and

at least one stop member for maintaining a gap distance between the first and second electrodes when handle is moved to the second position such that the end effectors and the electrodes are closer relative to one another, the gap distance being in the range of about 0.001 inches to about 0.006 inches.

30. A bipolar electrosurgical instrument according toclaim 29 wherein the gap distance is in the range of about 0.002 inches to about 0.005 inches.

31. A bipolar electrosurgical instrument comprising:

a handle;

a drive rod assembly comprising:

an outer shaft having an end effector assembly attached to a distal end thereof, the end effector assembly including a pair of opposing first and second electrodes attached at a distal end thereof, the end effector assembly having an inner nose portion electrically coupled to the first electrode and an outer nose portion electrically coupled to the second electrode;

a drive rod disposed within the outer shaft, the drive rod movable by the handle from a first position wherein the first and second electrodes are disposed in spaced relation to one another to a second position wherein the first and second electrodes are closer relative to one another such that the electrodes hold tissue therebetween for application of electrosurgical energy; and

a connector for electrically connecting the first and second electrodes to a source for supplying electrosurgical energy to each of the electrodes such that the first electrode has a first electrical potential and the second electrode has a second electrical potential.

32. A bipolar electrosurgical instrument according toclaim 31 wherein the connector includes a PC board having first and second clips, the first clip transmits the first electrical potential to the shaft which conducts the first electrical potential to the outer nose portion and the first electrode and the second clip transmits the second electrical potential to the drive rod which conducts the second electrical potential to the inner nose portion and the second electrode.

33. A bipolar electrosurgical instrument according toclaim 31 wherein the drive rod is electrically isolated from the outer shaft.

34. A bipolar electrosurgical instrument according toclaim 31 wherein the inner nose portion and the outer nose portion are electrically isolated from each other.

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