JP4975768B2 - An electrosurgical instrument that reduces incidental damage to adjacent tissue - Google Patents

Description

(Cross-reference of related applications)
This application is a U.S. application 09 / 387,883 filed on Sep. 1, 1999 (which is a continuation of U.S. application 08 / 968,496 filed on Nov. 12, 1997). , The entirety of which is incorporated herein by reference).

(background)
The present disclosure relates to electrosurgical instruments used for open and endoscopic surgical procedures. More specifically, the present disclosure relates to bipolar forceps for sealing blood vessels and vascular tissue so that the forceps limit and / or reduce thermal diffusion to adjacent tissue structures. It has a designed electrode assembly.

(Technical field)
A hemostatic forceps or forceps is a simple pliers-like tool that uses mechanical movements between its jaws to clamp tissue and, in general, to grasp, dissect and / or clamp tissue And used in open surgical procedures. Electrosurgical forceps utilize both mechanical clamping action and electrical energy to provide hemostasis by heating tissue and blood vessels to coagulate, cauterize and / or seal the tissue.

  Using electrosurgical forceps, the surgeon can cauterize, coagulate / dry, and / or simply bleed by controlling the intensity, frequency and duration of electrosurgical energy applied to the tissue. It can be reduced or delayed. In general, the electrical configuration of electrosurgical forceps can be divided into two categories: 1) monopolar electrosurgical forceps; and 2) bipolar electrosurgical forceps.

  Monopolar forceps utilize one active electrode with a clamping end effector and a remote patient return electrode or pad that is externally attached to the patient. When electrosurgical energy is applied, this energy is transferred from the active electrode to the surgical site and through the patient to the return electrode.

  Bipolar electrosurgical forceps utilize two generally opposed electrodes, which are generally placed on the inward or opposite surface of the end effector, which in turn is electrically connected to the electrosurgical generator. Connected. Each electrode is charged to a different potential. Since tissue is a conductor of electrical energy, this electrical energy can be selectively transmitted through the tissue when the end effector is used to clamp or grasp the tissue therebetween.

  Over the past decades, traditional access to vital organs and body cavities using endoscopes and endoscopic instruments (which access organs through small puncture-like incisions) Increasingly, surgeons praise the open methods. The endoscopic instrument is inserted into the patient via a cannula or port (which is made with a trocar). Typical sizes for cannulas range from 3 millimeters to 12 millimeters. Smaller cannulas are usually preferred, but as can be appreciated, this is ultimately designed for instrument manufacturers who must find a way to produce a suitable surgical instrument via the cannula. The above challenges are shown.

  Certain surgical procedures require sealing blood vessels or vascular tissue. However, because of spatial limitations, it is difficult for surgeons to perform sutures on blood vessels or other traditional methods to suppress bleeding (eg, clamping and / or tying sideways incised blood vessels). Can be. Blood vessels can often be closed using standard electrosurgical techniques in the range of less than 2 millimeters in diameter. If larger vessels are cut, the surgeon may need to switch the endoscopic procedure to an open surgical procedure, thereby abandoning the advantages of laparoscopy.

  It is known that the process of coagulating small blood vessels differs in principle from vascular sealing. For purposes herein, the term “coagulation” is defined as the process by which tissue cells rupture and dry dry tissue. The term “vascular sealing” is defined as the process of liquefying the collagen in a tissue so that the tissue crosslinks and reforms into a fused mass. Thus, clotting of small blood vessels is sufficient to close them, but larger blood vessels need to be sealed to ensure permanent closure.

Several academic papers disclose methods for sealing small blood vessels using electrosurgery. Title Studies on Coagulation and the Developmentof an Automatic Computerized Bipolar paper Coaqulator (Non-Patent Document 1) describes a bipolar coagulator which is used to seal small blood vessels. This article states that arteries with diameters greater than 2-2.5 mm cannot be safely coagulated. The second paper, titled “Automatically Controlled Bipolar Electrocoagulation” — “COA-COMP” ( Non-Patent Document 2 ), describes a method for terminating electrosurgical force on a blood vessel so as to avoid charring of the blood vessel wall. is doing.

  Accurate two main mechanical parameters (pressure applied to the vessel and gap between electrodes (both of which affect the thickness of the sealed vessel)) to provide a proper seal for larger vessels Must be controlled. More specifically, accurate application of pressure is important for several reasons: 1) to face the walls of the blood vessel; 2) to pass sufficient electrosurgical energy through the tissue To lower the tissue impedance to a sufficiently low value; 3) to overcome the expansion force during tissue heating; and 4) to contribute to the final tissue thickness, which is an indicator of a good seal. In some examples, the fused vessel wall is optimally between 0.001 inch and 0.006 inch. Below this range, the seal can be torn or torn, and above this range, the lumen may not be properly or effectively sealed.

A number of bipolar electrosurgical instruments have been proposed in the past for various open and endoscopic surgical procedures. However, some of these designs may not provide a uniformly reproducible pressure on the blood vessel and may result in an ineffective or non-uniform seal. For example, Patent Document 1 to Willis, Patent Document 2 and Patent Document 3 to Hiltebrandt, Patent Document 4 and Patent Document 5 to Boebel et al . , Patent Document 7 and Patent Document 8 , and Patent Document 9 and Patent Document 10 to Lottic , Patent Document 13 for Patent Document 12 and Richardson et al for Patent Document 11, Eggers et al for Stern et al., all of the vessels or tissue, coagulation, to electrosurgical instrument for sealing and cutting.

  Many of these instruments comprise blade members or shear members that simply cut tissue in a mechanical and / or electromechanical manner and are relatively ineffective for vascular sealing purposes. Other instruments generally rely only on clamping pressure to obtain the proper sealing thickness, and often require clearance tolerances and / or parallelism and flatness requirements (if these are properly controlled, It is not designed with consideration given to parameters that can guarantee a consistent and effective tissue seal. For example, it is known that it is difficult to properly control the thickness of the resulting seal tissue by controlling only the clamping pressure for either of the following two reasons: 1) If the force applied is too great, the two poles may touch and not transfer energy through the tissue, resulting in an ineffective seal; or 2) if the applied force is too low, it is thicker and more reliable A low seal is produced.

  It has been found that when tissue is sealed using electrosurgical instruments, some so-called “heat diffusion” can occur across adjacent tissue structures. For purposes herein, the term “thermal diffusion” generally refers to heat transfer (heat conduction, heat convection or current loss) that travels along the periphery of a conductive surface. This can also be referred to as “collateral damage” to adjacent tissue. As can be appreciated, reducing thermal diffusion during an electrical procedure reduces the possibility of unintentional or undesirable incidental damage to surrounding tissue structures adjacent to the intended treatment site. .

  Instruments with a dielectric coating disposed along the outer surface are known and are used to prevent the tissue from “branching” at normal points relative to the sealing site. In other words, these coatings are primarily designed to reduce accidental burning of tissue as a result of accidental contact with the outer end effector. As far as is known, these coatings are not designed to reduce collateral tissue damage or thermal diffusion to adjacent tissue (tissue located along the tissue plane) It has not been.

  Various electrosurgical instruments have been introduced and are known to solve many of the above-mentioned problems associated with sealing, cutting, cauterizing and / or coagulating different sized blood vessels. Some of these devices are co-pending US patent application Ser. No. 09 / 178,027, filed Oct. 23, 1998, entitled OPENVESELSEL SEALING FORCEPS WITH DISPOSABLE ELECTRODES; filed Oct. 22, 1999. US Patent Application No. 09 / 425,696, Title OPENVESELSEL SEALING FORCEPS WITH DISPOSABLE ELECTRODES; copending US Patent Application No. 09 / 177,950 filed October 23, 1998; Co-pending US patent application Ser. No. 09 / 621,029 filed 21 days, title ENDOSCOPICBI OLAR ELECTROSURGICAL FORCEPS (the entire contents all of which are incorporated by reference herein) is described.

U.S. Pat. No. 2,176,479 US Pat. No. 4,005,714 U.S. Pat. No. 4,031,898 US Pat. No. 5,827,274 US Pat. No. 5,290,287 US Pat. No. 5,312,433 US Pat. No. 4,370,980 US Pat. No. 4,552,143 US Pat. No. 5,026,370 US Pat. No. 5,116,332 US Pat. No. 5,443,463 US Pat. No. 5,484,436 US Pat. No. 5,951,549

J. et al. Neurosurg. 75, July 1991. Neurosurg. Rev. (1984), pp. 187-190

  Thus, there is a need to develop an electrosurgical instrument with an electrode assembly that can consistently and effectively seal blood vessels and tissues and reduce the effects of undesirable heat diffusion across the tissue structure.

(Summary)
The present disclosure relates generally to open electrosurgical instruments and / or endoscopic electrosurgical instruments, which include a removable electrode assembly that includes a uniquely designed insulating substrate and conductive surface. , Having electrodes electrically or thermally separated from the rest of the instrument. It is envisioned that this insulating substrate geometry relative to the sealing surface geometry contributes to an overall reduction in incidental damage to adjacent tissue structures.

  More particularly, the present disclosure relates to an electrode assembly for use with an electrosurgical instrument that includes opposing end effectors and a handle for moving the end effectors relative to each other. The assembly includes a housing, the housing having at least a portion removably engageable with at least a portion of an electrosurgical instrument (eg, handle, end effector, pivot, shaft, etc.) and a pair of electrodes. Each electrode is preferably dimensioned to include a conductive sealing surface and an insulating substrate and to be selectively engageable with the end effector so that the electrodes are positioned in opposing relation to each other. To do.

  Preferably, the size of the insulating substrate is different from the size of the conductive sealing surface that reduces thermal diffusion to adjacent tissue. For example, in one embodiment of the present disclosure, the cross section of the conductive sealing surface is different from the cross section of the insulating substrate that effectively reduces thermal diffusion to adjacent tissue.

  In other embodiments, the insulative substrate is conductively sealed by stamping, overmolding, overmolding a stamped seal plate, and / or by overmolding a metal injection molded seal plate. Attached to the surface. All of these manufacturing techniques produce an electrode having a conductive surface substantially surrounded by an insulating substrate. These uniquely described embodiments described herein are contemplated to effectively reduce thermal diffusion to adjacent tissue structures during and / or immediately after actuation. The conductive sealing surface may also include a pinch trim that facilitates positive engagement of the conductive surface to the insulating substrate and also simplifies the entire manufacturing process.

  In another embodiment, the conductive sealing surface comprises an outer periphery, the outer periphery has a constant radius, and an insulator mates with the conductive sealing surface along an adjacent edge, the adjacent edge Is approximately tangential to the radius and / or fits along this radius. Preferably, at the interface, the conductive surface is raised relative to the insulator.

  The insulating substrate can be made of plastic or a plastic-based material having a comparative tracking index of about 300 volts to about 600 volts. Preferably, the insulating substrate is made from a group of materials including: nylon, syndiotactic polystyrene (SPS), polybutylene terephthalate (PBT), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), poly Phthalamide (PPA), polymide, polyethylene terephthalate (PET), polyamide-imide (PAI), acrylic (PMMA), polystyrene (PS and HIPS), polyethersulfone (PES), aliphatic polyketone, acetal (POM) copolymer, Polyurethane (PU and TPU), nylon dispersed with polyphenylene oxide, and acrylonitrile styrene acrylate. Alternatively, non-plastic insulating materials (eg, ceramics) are used in place of the materials specified above or in combination with one or more of those materials, facilitating the manufacturing process, and uniform and consistent sealing And / or possibly contribute to the overall reduction in thermal diffusion to adjacent tissue structures.

  In another embodiment of the present disclosure, the insulating substrate of each electrode comprises at least one mechanical interface to engage a complementary mechanical interface disposed on a corresponding end effector of the instrument. Preferably, the mechanical interface of the substrate comprises a detent and the corresponding end effector mechanical interface comprises a complementary socket to receive the detent.

  Other embodiments of the present disclosure include a housing that has a bifurcated distal end that forms two prongs that are resilient and flexible, each prong associated with a corresponding end effector. With electrodes designed to match. In another embodiment, the end effector is disposed at an angle alpha (α) relative to the distal end of the shaft of the electrosurgical instrument. Preferably, this angle is from about 60 ° to about 70 °. The end effector and then the electrode can also be dimensioned to have a taper along the width “W” (see FIG. 2).

  The present disclosure also relates to an electrode assembly for use with an electrosurgical instrument having a handle and at least one shaft that provides movement of a pair of opposing end effectors relative to each other. The electrode assembly includes a housing that is removably engageable with a shaft and / or handle and a pair of electrodes. Each electrode is removably engageable with a corresponding end effector and includes a conductive sealing surface having a first geometry and an insulating substrate having a second geometry. Preferably, the second geometry of the insulating substrate is different from the first geometry of the sealing surface, which effectively reduces heat diffusion to adjacent tissue structures during instrument operation. Let

Preferably, the electrode assembly is removable, disposable and replaceable after the electrode assembly has been used beyond its intended number of operating cycles. Alternatively, the electrode assembly and / or electrode can be integrally coupled with the instrument end effector and is not removable. In this example, an electrosurgical instrument (open or endoscopy) can be designed to be applied for a single use, and the entire instrument is completely disposable after the surgery is complete.
More specifically, the present invention can relate to the following items.
(Item 1)
An electrode assembly for use with an electrosurgical instrument, the electrosurgical instrument comprising opposing end effectors and a handle for effecting movement of the end effectors relative to each other, the electrode assembly comprising:
A housing having at least one portion removably engaged with at least a portion of the instrument;
A pair of electrodes, each of said electrodes comprising a conductive sealing surface and an insulating substrate, said electrodes being removed from said end effector of said instrument such that said electrodes are in opposing relationship to each other An electrode that is engagably engageable, and
Wherein the dimensions of the insulating substrate are different from the dimensions of the conductive sealing surface to reduce thermal diffusion into adjacent tissue structures.
(Item 2)
The electrode assembly of claim 1, wherein the insulating substrate is made from a material having a comparative tracking index of about 300 volts to about 600 volts.
(Item 3)
The insulating base material is nylon, syndiotactic polystyrene, polybutylene terephthalate, polycarbonate, acrylonitrile butadiene styrene, polyphthalamide, polyimide, polyethylene terephthalate, polyamide-imide, acrylic, polystyrene, polyethersulfone, aliphatic polyketone, acetal copolymer The electrode assembly according to item 1, selected from the group consisting of polyurethane, nylon dispersed with polyphenylene oxide, and acrylonitrile styrene acrylate.
(Item 4)
Item 2. The electrode assembly of item 1, wherein the insulating substrate is attached to the conductive sealing surface by overmolding a stamped seal plate.
(Item 5)
Item 2. The electrode assembly of item 1, wherein the insulating substrate is attached to the conductive sealing surface by overmolding a metal injection molded seal plate.
(Item 6)
The electrode assembly of claim 1, wherein the conductive sealing surface of at least one electrode comprises a pinch trim and the insulating substrate extends beyond the periphery of the conductive sealing surface.
(Item 7)
The electrode assembly of claim 1, wherein the insulating substrate of each of the electrodes comprises at least one mechanical interface for engaging a complementary mechanical interface disposed on the corresponding end effector of the instrument. .
(Item 8)
At least one of the mechanical interfaces of the substrate comprises at least one detent and the mechanical interface of the corresponding end effector comprises at least one complementary socket for receiving the detent; 8. The electrode assembly according to item 7.
(Item 9)
The electrode of claim 1, wherein the housing comprises a bifurcated distal end, the distal end forms two prongs, and each prong is removably attached to one of the end effectors. assembly.
(Item 10)
The electrode assembly according to item 1, wherein at least one of the opposing end effector and the opposing electrode is tapered.
(Item 11)
The electrode assembly of claim 1, wherein the end effector is disposed at an angle with respect to the shaft of the electrosurgical instrument.
(Item 12)
12. The electrode assembly of item 11, wherein the angle is from about 60 degrees to about 70 degrees.
(Item 13)
2. The electrode assembly according to item 1, wherein the electrode assembly is disposable.
(Item 14)
An electrode assembly for use with an electrosurgical instrument, the electrosurgical instrument having a handle and at least one shaft for causing movement of a pair of opposing end effectors relative to each other. And the electrode assembly is as follows:
A housing having at least one portion removably engageable with at least one of the handle and the shaft;
A pair of electrodes, each of the electrodes comprising a conductive sealing surface having a first geometric shape and an insulating substrate having a second geometric shape, wherein the electrodes are An electrode removably engageable with the end effector of the instrument so as to face each other;
Wherein the second geometric shape of the insulating substrate is different from the first geometric shape of the sealing surface to reduce heat diffusion to adjacent tissue structures. And
Wherein the insulating substrate is made of a material having a comparative tracking index of about 300 volts to about 600 volts.
(Item 15)
Item 15. The electrode assembly of item 14, wherein the conductive sealing surface of at least one electrode comprises a pinch trim and the insulating substrate extends beyond the periphery of the electrode.
(Item 16)
The insulating base material is nylon, syndiotactic polystyrene, polybutylene terephthalate, polycarbonate, acrylonitrile butadiene styrene, polyphthalamide, polyimide, polyethylene terephthalate, polyamide-imide, acrylic, polystyrene, polyethersulfone, aliphatic polyketone, acetal copolymer 15. The electrode assembly according to item 14, selected from the group consisting of polyurethane, nylon dispersed with polyphenylene oxide, and acrylonitrile styrene acrylate.
(Item 17)
15. The electrode assembly of item 14, wherein the insulating substrate is attached to the conductive sealing surface by overmolding a stamped seal plate.
(Item 18)
Item 15. The electrode assembly of item 14, wherein the insulating substrate is attached to the conductive sealing surface by overmolding a metal injection molded seal plate.
(Item 19)
An electrode assembly for use with an electrosurgical instrument, the electrosurgical instrument comprising opposing end effectors and a handle for effecting movement of the end effectors relative to each other, the electrode assembly comprising:
A housing having at least one portion removably engageable with at least a portion of the instrument;
A pair of electrodes, each of said electrodes comprising a conductive sealing surface and an insulating substrate, said electrodes being removed from said end effector of said instrument such that said electrodes are in opposing relationship to each other Electrodes that are engageable,
Wherein the outer periphery of at least one conductive sealing surface has a radius, and the insulator is conductive along an adjacent edge that is substantially tangential to the radius. An electrode assembly facing the sealing surface.
(Item 20)
Item 20. The item 19, wherein the outer peripheral edge of at least one conductive sealing surface comprises a radius and the insulator faces the conductive sealing surface along an adjacent edge along the radius. Electrode assembly.
(Item 21)
20. An electrode assembly according to item 19, wherein the conductive sealing surface is raised with respect to the insulator.
(Item 22)
An electrode assembly for use with a disposable electrosurgical instrument, the disposable electrosurgical instrument comprising a handle and at least one shaft for effecting movement of a pair of opposing end effectors relative to each other, the electrode assembly The following:
housing;
A pair of electrodes, each of the electrodes comprising a conductive sealing surface having a first geometric shape and an insulating substrate having a second geometric shape, wherein the electrodes are An electrode integrally coupled with the end effector of the instrument so as to face each other
Wherein the second geometric shape of the insulating substrate is different from the first geometric shape of the sealing surface to reduce heat diffusion to adjacent tissue structures. And wherein the insulating substrate has a comparative tracking index of about 300 volts to about 600 volts.

FIG. 1 is a perspective view of an open bipolar forceps according to one embodiment of the present disclosure. FIG. 2 is an enlarged perspective view of the distal end of the bipolar forceps shown in FIG. FIG. 3 is a perspective view of a disassembled part of the forceps shown in FIG. FIG. 4 is an enlarged side view of the electrode assembly of FIG. 1 shown without a cover plate. FIG. 5 is an enlarged perspective view of the distal end of the electrode assembly of FIG. 6 is a perspective view of an exploded part of the upper electrode of the electrode assembly of FIG. 7A is a perspective view of an exploded part of the lower electrode of the electrode assembly of FIG. FIG. 7B is a cross-sectional view of a prior art electrode arrangement where the electrodes extend across the sides of the insulator. FIG. 7C is a cross-sectional view of the electrode with the insulator extending beyond the sides of the radiused electrode. FIG. 7D is a cross-sectional view of an overmolded stamped electrode arrangement showing an insulator that has captured a pinch trim depending from the conductive surface. FIG. 7E is a cross-sectional view of an electrode arrangement showing a barrier made according to certain rules at the periphery of the electrode in an opposed position and an insulator that controls / adjusts the heat dissipated from the sealing surface. FIG. 8A is a perspective view of an open forceps of the present disclosure showing the operational motion of the forceps for sealing a tubular vessel. FIG. 8B is a perspective view of an endoscopic version of the present disclosure showing the operational movement of an instrument for sealing a tubular vessel. FIG. 9 is an enlarged partial perspective view of a sealing site of a tubular blood vessel. FIG. 10 is a longitudinal cross-sectional view of the sealing site taken along line 10-10 of FIG. 11 is a longitudinal cross-sectional view of the sealing site of FIG. 9 after separation of the tubular blood vessel. FIG. 12 is a contour plot showing the electrosurgical current dissipation across the tissue when using an electrode without an insulator. FIG. 13A is a contour plot showing electrosurgical current dissipation across tissue when using electrodes with flash insulators. FIG. 13B is an enlarged contour plot of FIG. 13A showing the current density and relative dissipation of the electrosurgical current at the adjacent edge or interface between the insulator and the conductive sealing surface. FIG. 13C is an enlarged electric field strength plot of the electrode arrangement of FIG. 13A showing the current density and relative dissipation of the electrosurgical electric field distribution at the adjacent edge or interface between the insulator and the conductive sealing surface. FIG. 14A is a contour plot showing the dissipation of electrosurgical current across tissue when using an electrode with an elevated conductive surface and a round shaped interface between the conductive surface and the insulator. FIG. 14B is an enlarged contour plot of FIG. 14A showing the current density and relative dissipation of the electrosurgical current at the adjacent edge or interface between the insulator and the conductive sealing surface. FIG. 14C is an expanded field strength plot of the electrode arrangement of FIG. 14A showing the current density and relative dissipation of the electrosurgical electric field distribution at the adjacent edge or interface between the insulator and the conductive sealing surface. . FIG. 15 is a contour plot showing electrosurgical current dissipation across tissue when using an electrode with a raised conductive surface and a 90 ° interface between the conductive surface and the insulator.

(Detailed explanation)
By changing the placement of the electrode insulation material with respect to the conductive sealing surface, the surgeon can more easily and more easily create a consistent, high quality seal that heats over or to adjacent tissue. It has been found that general diffusion can be efficiently reduced. For purposes herein, “thermal diffusion” refers to heat transfer generally dissipated along the periphery of a conductive or electrically active surface to adjacent tissue (thermal conduction, thermal convection, Or current dissipation). This can also be referred to as “collateral damage” to adjacent tissue. It is envisioned that the placement of insulating material surrounding the periphery of the conductive surface effectively reduces current and heat dissipation to adjacent tissue parts and generally limits the conduction to the region between the facing electrodes. The As noted above, this is different from dielectrically coating the outer surface of the device to prevent tissue “branching” at normal points relative to the sealing site. These coatings are not designed or intended to reduce collateral tissue damage or thermal diffusion to adjacent tissue (tissue present along the tissue sealing plane).

  More specifically, by changing the insulator geometry relative to the conductor surface, the current path is altered, thereby affecting thermal diffusion / collateral damage to adjacent tissue structures. It is intended to give. Preferably, the shape of this insulating material also isolates the two electrically opposing poles (ie, electrodes) from each other so that the tissue or tissue fluid has an unintended bridge or path for current transfer. Reduce the potential to create. In other words, the insulator and the conductive sealing surface are preferably dimensioned so that the current is at the intended sealing site between opposing conductive surfaces, as will be described in more detail below. Concentration is expected.

  1-3, by way of example, a bipolar forceps 10 is shown for use in conjunction with an open surgical procedure, which includes a mechanical forceps 20 and a disposable electrode assembly 21. In the drawings and the following description, the term “proximal” traditionally means the end of the forceps 10 that is closer to the user, while the term “distal” is the end that is farther from the user. Means. Further, most of the figures (ie, FIGS. 1-7A and 8A) show one embodiment of an instrument described in the present invention (eg, forceps 20) for use with an open surgical procedure, It is envisioned that the same properties shown and described herein may also be used with or in combination with endoscopic instrument 100, such as the embodiment illustrated by the example of FIG. 8B.

  1-3 show a mechanical forceps 20, which comprises a first member 9 and a second member 11, each of which has an elongated shaft 12 and 14, respectively. Each of the shafts 12 and 14 includes a proximal end 13 and 15 and a distal end 17 and 19, respectively. Each proximal end 13, 15 of each shaft portion 12, 14 includes a handle member 16 and 18 attached thereto, which allows the user to place at least one of the shaft portions (eg, 12) on the other ( For example, it can be moved with respect to 14). End effectors 24 and 22 extend from the distal ends 17 and 19 of each shaft portion 12 and 14, respectively. End effectors 24 and 22 are movable relative to each other with respect to movement of handle members 16 and 18.

  Preferably, the shaft portions 12 and 14 are secured to one another around the pivot axis 25 at a point proximal to the end effectors 24 and 22, so that one movement of the handles 16, 18 is end-to-end from the open position. The effectors 24 and 22 are moved relatively. Here, the end effectors 22 and 24 are arranged in a spaced relationship relative to each other with respect to the clamping or closed position, wherein the end effectors 22 and 24 have a tubular blood vessel 150 therebetween. Cooperate to grip (see FIGS. 8A and 8B). The pivot shaft 25 has a large surface area and is expected to suppress twisting and movement of the forceps 10 during operation. The forceps 10 can only be dimensioned such that movement of one or both of the handles 16 and 18 moves one of the end effectors (eg, 24) relative to the other end effector (eg, 22).

  As best shown in FIG. 3, end effector 24 includes an upper jaw member or first jaw member 44 having an inward surface 45 and a plurality of mechanical interfaces disposed thereon, These interfaces are dimensioned to removably engage a portion of the disposable electrode assembly 21 described in more detail below. Preferably, the mechanical interface comprises a socket 41, which is disposed at least partially through the inward surface 45 of the jaw member 44 and is attached to the upper electrode 120 of the disposable electrode assembly 21. Designed to accommodate a complementary detent 122. Although the term “socket” is used herein, either a female or male mechanical interface can be used for the jaw member 44, and the mated mechanical interface is on the disposable electrode assembly 21. It is contemplated that

  In some cases, a mechanical interface 41 is manufactured along another side of the jaw member 44 to engage the complementary mechanical interface of the disposable electrode assembly 21 in a different manner (eg, from that side). May be preferred. The jaw member 44 also includes an opening 67 disposed at least partially through the inwardly facing surface 45 of the end effector 24, which opening is complementary to the electrode 120 of the disposable electrode assembly 21. Dimensioned to accommodate guide pin 124.

  End effector 22 includes a second or lower jaw member 42 having an inward surface 47 opposite to inward surface 45. Preferably, jaw members 42 and 44 are sized approximately symmetrically. However, in some cases it may be preferable to produce two asymmetric jaw members 42 and 44 depending on the particular purpose. In exactly the same manner as described above for jaw member 44, jaw member 42 also includes a plurality of mechanical interfaces or sockets 43 disposed thereon, which are disposable electrode assembly 21 as described below. Sized to removably engage a complementary portion 112 disposed on the electrode 110. Similarly, the jaw member 42 also includes an opening 65 disposed at least partially through the inward surface 47, which is a complementary guide pin 127 (disposed on the electrode 110 of the disposable electrode assembly 21. (See FIG. 4).

  Preferably, end effectors 22, 24 (and, in turn, jaw members 42 and 44 and corresponding electrodes 110 and 120) are disposed at an angle alpha (α) with respect to distal ends 19, 17 (see FIG. 2). ). It is contemplated that this angle alpha (α) ranges from about 50 ° to about 70 ° with respect to the distal ends 19,17. It is envisioned that angling the end effector 22, 24 at an angle alpha (α) with respect to the distal end 19, 17 is advantageous for the following two reasons: 1) of the end effector, jaw members and electrodes Depending on the angle, a greater constant pressure is applied for a constant tissue thickness, and 2) the thicker proximal portion of this electrode, eg 110, (as a result of a taper along the width “W”) Because of the reaction force of the tissue 150, it does not yield to bending. The taper “W” shape of electrode 110 (FIG. 2) is determined by calculating the mechanical advantage variation from the distal end to the proximal end of electrode 110 and adjusting the width of electrode 110 accordingly. Is done. Sizing the end effector 22, 24 at an angle of about 50 ° to about 70 ° is useful for certain anatomical structures involved in prostatectomy and cystectomy (eg, dorsal vein complex and transverse stem ( lateral)) and evaluation.

  Preferably, the shaft members 12 and 14 of the mechanical forceps 20 are designed to transmit certain desired forces when clamped or to opposing inward surfaces of the jaw members 22 and 24, respectively. In particular, since the shaft members 12 and 14 work together effectively in a spring-like manner (ie, a spring-like bend), the length, width, height and deflection of the shaft members 12 and 14 are: It directly affects the total transmission force applied to the opposing jaw members 42 and 44. Preferably, the jaw members 22 and 24 are more rigid than the shaft members 12 and 14 and the strain energy stored in the shaft members 12 and 14 provides a constant closing force between the jaw members 42 and 44. provide.

  Each shaft member 12 and 14 also includes ratchet portions 32 and 34, respectively. Preferably, each ratchet (eg, 32) extends from the proximal end 13 of its respective shaft member 12 toward the other ratchet 34 in a substantially vertically aligned fashion, so that each ratchet 32 and 34 The inwardly facing surfaces contact each other as the end effectors 22 and 24 move from the open position to the closed position. Each ratchet 32 and 34 includes a plurality of flanges 31 and 33, respectively, that protrude from the inward surface of each ratchet 32 and 34 so that the ratchets 32 and 34 can be interlocked in at least one position. . In the embodiment shown in FIG. 1, ratchets 32 and 34 interlock in several different positions. Preferably, each ratchet position holds a specific (ie, constant) strain energy within the shaft members 12 and 14, which then applies a specific force to the end effectors 22 and 24, and thus the electrodes 120 and 110. introduce.

  In some cases it may be preferable to provide other mechanisms for controlling and / or limiting the movement of jaw members 42 and 44 relative to each other. For example, a ratchet and pawl system can be used to segment the movement of two handles to separate units, which then moves the jaw members 42 and 44 separately relative to each other.

  Preferably, at least one of the shaft members (eg, 14) includes a protrusion 99 that facilitates manipulation of the forceps 20 during a surgical condition and, as described in more detail below, The attachment of the electrode assembly 21 to the surgical forceps 20 is facilitated.

  As best shown in FIGS. 2, 3 and 5, the disposable electrode assembly 21 is designed to operate in combination with the mechanical forceps 20. Preferably, the electrode assembly 21 comprises a housing 71 having a proximal end 77, a distal end 76 and an elongated shaft plate 78 disposed therebetween. The handle plate 72 is disposed near the proximal end 77 of the housing 71 and is dimensioned to removably engage the handle 18 of the mechanical forceps 20 and / or surround the handle 18. Similarly, the shaft plate 78 is sized to surround and / or removably engage the pivot plate 74 disposed near the shaft 14 and the distal end 76 of the housing 71 and of the mechanical forceps 20. It is dimensioned to surround at least a portion of the pivot axis 25 and the distal end 19. The electrode assembly 21 may be manufactured to engage either the first member 9 or the second member 11 of the mechanical forceps 20 and any of its respective component parts 12, 16 or 14, 18.

  In the embodiment shown in FIG. 3, the handle 18, the shaft 14, the pivot axis 25, and a portion of the distal end 19 are all sized to fit a corresponding channel disposed within the housing 71. For example, channel 139 is sized to receive handle 18, channel 137 is sized to receive shaft 14, and channel 133 receives pivot 25 and a portion of distal end 19. It is a size to do.

  The electrode assembly 21 also includes a cover plate 80 that is also designed to surround and / or engage the mechanical forceps 20 in a manner similar to that described with respect to the housing 71. More specifically, cover plate 80 includes a proximal end 85, a distal end 86 and an elongated shaft plate 88 disposed therebetween. The handle plate 82 is disposed near the proximal end 85 and is preferably sized to removably engage and / or surround the handle 18 of the mechanical forceps 20. Similarly, the shaft plate 88 is dimensioned to surround and / or removably engage the shaft 14 and the pivot plate 94 disposed near the distal end 86 is the pivot axis of the mechanical forceps 20. 25 and the distal end 19 are designed to surround. Preferably, the handle 18, shaft 14, pivot 25 and distal end 19 are all corresponding channels (not shown) disposed in the cover plate 80 in a manner similar to that described above with respect to the housing 71. It is the size that fits.

  As best shown with respect to FIGS. 3 and 4, the housing 71 and the cover plate 80 are designed to engage each other on the first member (eg, 11) of the mechanical forceps 20, so that The first member 11 and its respective component parts (eg, handle 18, shaft 14, distal end 19 and pivot axis 25) are disposed therebetween. Preferably, the housing 71 and cover plate 80 comprise a plurality of mechanical interfaces that are arranged at various locations along the interior of the housing 71 and cover plate 80 to provide mechanical engagement with each other. More specifically, a plurality of sockets 73 are disposed near the handle plate 72, shaft plate 78, and pivot plate 74 of the housing 71 and extend from the cover plate 80 and corresponding detents (not shown). Are dimensioned to removably engage. Either a male mechanical interface or a female mechanical interface, or a combination of mechanical interfaces, can be disposed in the housing 71 with a mating mechanical interface disposed on or in the cover plate 80. It is assumed that

  As best shown with respect to FIGS. 5-7A, the distal end 76 of the electrode assembly 21 has two prong-like members 103 and 105 extending outwardly from the distal end 76 so that the electrodes 110 and 120. Branches to support each. More particularly, the electrode 120 is attached to the end 90 of the prong 105 and the electrode 110 is attached to the end 91 of the prong 103. It is envisioned that electrodes 110 and 120 can be applied to ends 91 and 90 in any known manner (eg, friction fit, slide fit, snap fit engagement, crimping, etc.). Further, it is contemplated that the electrodes 110 and 120 may be selectively removable from the ends 90 and 91 depending on the particular purpose and / or to facilitate assembly of the electrode assembly 21. .

  A pair of wires 60 and 62 are connected to electrodes 120 and 110, respectively, as best shown in FIGS. Preferably, the wires 60 and 62 are bundled together and form a wire bundle 28 (FIG. 4), which extends from the terminal connector 30 (see FIG. 3) to the proximal of the housing 71. End 77 extends along the interior of housing 71 to distal end 76. Wire bundle 28 separates into wires 60 and 62 near distal end 76, and wires 60 and 62 are connected to respective electrodes 120 and 110, respectively. In some cases, wires 60 and 62 are captured within electrode assembly 21 by capturing wires 60 and 62 or wire bundle 28 at various pinch points along the inner cavity of electrode assembly 21 and attaching cover plate 80. It may be preferred to surround

  This arrangement of the wires 60 and 62 is designed to be convenient for the user so that it hardly interferes with the operation of the bipolar forceps 10. As described above, the proximal end of the wire bundle 28 is connected to the terminal connector 30, but in some cases it is preferred to extend the wires 60 and 62 to an electrosurgical generator (not shown). It can be.

  As best shown in FIG. 6, the electrode 120 includes a conductive sealing surface 126 and an electrically insulating substrate 121, which can be snap fit engaged or some other assembly method (eg, stamping). Of each other by overmolding or metal injection molding). Preferably, the substrate 121 is made from a molded plastic material and is molded to mechanically engage a corresponding socket 41 disposed in the jaw member 44 of the end effector 24 (see FIG. 2). See This substrate 121 not only insulates the current but also aligns the electrodes 120, both of which contribute to seal quality, consistency, and reduced heat spread through the tissue. Further, by attaching conductive surface 126 to substrate 121 using one of the above assembly techniques, the alignment and thickness (ie, height “h2”) of electrode 120 can be controlled. For example, as best illustrated by comparing FIGS. 7B and 7C, the overmolding manufacturing technique is compared to the conventional manufacturing technique (which results in a height of “h1”) (FIG. 7B): The overall height “h2” of the electrode 120 (FIG. 7C) is decreased. The lower height “h2” allows the user access to smaller areas within the body and facilitates sealing around more sensitive tissue areas.

  In addition, overmolding technology provides higher insulation along the sides of the electrically conductive surface, which is also intended to reduce heat spread by reducing the number of electrodes in contact with the tissue. . By dimensioning the substrate (eg, 121) and the electrode 120 in this manner (ie, having a reduced conductive surface area), current is passed through the tissue outside the seal area that can be contacted with the outer end of the electrode 120. The current is limited (ie, concentrated) to the intended seal area (see FIG. 7B).

  Preferably, the substrate 121 includes a plurality of branched detents 122 that compress during insertion into the socket 41 and expand after insertion to removably engage the socket 41. Formed as follows. It is envisioned that the snap fit engagement of electrode 120 and jaw member 44 accommodates a wider range of manufacturing tolerances. The substrate 121 also includes an alignment or guide pin 124 that is dimensioned to engage the aperture 67 of the jaw member 44. The slide-fit technique is also described, for example, by Tezlaff et al. With respect to the sharing copending US application number 203-2348CIP2PCT, the entire contents of which are hereby incorporated by reference herein. Contemplate fit technology.

  The conductive sealing surface 126 includes a wire crimp 145 designed to engage the distal end 90 of the prong 105 of the electrode assembly 21 and a corresponding wire attached to the wire 60 disposed within the electrode assembly 21. Electrically engages the connector. The sealing surface 126 also includes an opposing surface 125 that, when held against the tubular vessel or tissue 150, transmits an electrosurgical current to the tubular vessel or tissue 150. Designed.

  Electrode 110 comprises similar elements and materials for isolating electrosurgical current and for transmitting electrosurgical current to tissue 150. More particularly, the electrode 110 comprises an electrically conductive sealing surface 116 and an electrically insulating substrate 111, which are attached to one another by one of the above assembly methods. The substrate 111 includes a plurality of detents 112 that are dimensioned to engage a corresponding plurality of sockets 43 and openings 65 disposed on the jaw member 42. The conductive sealing surface 116 includes an extension 155 having a wire crimp 119 that engages the distal end 91 of the prong 103 and a corresponding wire attached to a wire 62 disposed within the housing 71. Electrically engages the connector. The sealing surface 116 also includes an opposing surface 115 that, when held against the tubular vessel or tissue 150, transmits an electrosurgical current to the tubular vessel or tissue 150. It is contemplated that electrodes 110 and 120 can be formed as one piece and have similar components and / or dimensions for insulating and conducting electrical energy in a manner that effectively reduces heat spread. .

  As mentioned above, it is envisioned that the heat spread can be reduced by changing the physical dimensions of the insulator and electrode (eg, by changing the outer shape / shape of the insulator). Manufacturing electrodes 110 and 120 in this manner is envisioned to reduce heat spread and stray currents that can be transferred to the electrosurgical instrument. The stray current can be further increased by casting the forceps and / or by manufacturing the forceps using a non-conductive material and / or by coating the ends of the electrodes 110 and 120 with an insulative coating. Can be limited.

  For example, as best shown by comparing FIG. 7B (prior art) to the newly disclosed FIGS. 7C, 7D, 14A and 14B, the substrates 111, 121 have a width “W” (FIG. 2). Designed to extend along, so that the width of the insulating substrate (eg, 111) exceeds the width of the electrically conductive seal surface (eg, 116). It is envisioned that these electrically conductive sealing surface 116 and insulator 111 configurations can be achieved by various manufacturing techniques (eg, stamping overmolding and / or metal injection molding). Stamping is defined herein to encompass virtually any pressing operation known in the art, including but not limited to: blanking, shearing, hot Forming or cold forming, drawing, bending and coining. Other manufacturing techniques can also be used to achieve similar electrically conductive sealing surfaces 116 and insulators 111 that effectively reduce the spread of heat to adjacent tissue.

  Manufacturing electrodes 110 and 120 in this manner reduces the spread of heat to adjacent tissue structures and possibly reduces the electric field potential, thereby reducing stray currents that are then conducted through the instrument body. is assumed. Varying the relative position of the insulator 111 relative to the electrically conductive surface 116 also isolates the two opposing poles during operation so that the tissue or tissue fluid can stray to the surrounding tissue. Reduce the possibility of connecting routes for transmission of As best shown in FIG. 7D, the electrode 116 may also include a pinch trim 131, which is the insulator 111 and electrically conductive sealing surface during the assembly and / or manufacturing process. Facilitates stable and complete engagement with 116.

  FIG. 7E illustrates another embodiment of the present disclosure where compliant material 161 is disposed around the outer surface of electrically conductive sealing surfaces 116, 126 and substrates 111, 121. This compliant material 161 is supposed to act as a mechanical barrier by limiting the heat and vapor generated from the sealing surface, thereby reducing the spread of heat to the surrounding tissue. One or more barriers 161 may be attached to the end effector 22, 24 and / or the insulating substrate 111, 121 depending on the particular purpose to achieve a particular result.

  14A, 14B, 14C and 15 show that the electrically conductive sealing surface 116, 126 is relatively high with the insulating coating or insulator 111,121. Preferably, the electrical sealing surfaces 116, 126 are rounded or curved, thereby reducing current concentration and dissipation of stray currents to surrounding tissue structures. Insulators 111, 121 and electrically conductive sealing surfaces 116, 126 may be dimensioned to fit or generally lie along the interface or adjacent longitudinally oriented edges 129, 139. To reduce the current concentration 141 and current dissipation proximate the interfaces 129, 139 and the opposing electrically conductive surfaces 116, 126.

  For example, by way of example, FIGS. 12 and 13A-13C show other electrode 110, 120 arrangements known in the prior art. FIG. 12 shows an example of non-insulating (ie, without insulators 111, 121) opposing electrodes 110, 120 during operation, which is opposed to the electrically conductive sealing surfaces 116, 126 opposing. Illustrates the electric field distribution 135 generated from (current is known to flow perpendicular to these electric field lines). As can be appreciated, the electric field 135 occurs well beyond the intended site of treatment. This can cause increased collateral tissue damage and possibly amputation.

  By providing insulators 111, 121 that are flush with the electrically conductive sealing surfaces 116, 126 as shown in FIGS. 13A-13C, the electric field distribution 135 can be significantly reduced. However, as the enlarged views of FIGS. 13B and 13C illustrate, the current concentration 141 tends to occur between the opposing electrically conductive surfaces 116, 126 and at or near the interfaces 129, 139. There is. This current concentration 141 can also lead to negative effects and possibly cause tissue cutting or tissue sticking to the electrode or electrically conductive surface at this site.

  14A-15 show various electrode 110, 120 arrangements in accordance with the present disclosure, where the electrically conductive sealing surfaces 116, 126 and insulators 111, 121 are between the opposing electrodes 110, 120. Designed to reduce the amount of current concentration 141. More specifically, FIGS. 14A and 14B show a pair of high electrically conductive sealing surfaces 116, 126 (relative to insulators 111, 121) that have radii “r” and “r ′”, respectively. Having outer surfaces 145, 147. Preferably, the insulators 111, 121 are in contact with the outer surfaces 145, 147 and form adjacent edges or interfaces 129, 139 that run along radii “r” and “r ′”, respectively. By shaping the electrodes 110, 120 in this manner, it is envisioned that the current concentration 141 between the outer surfaces 145, 147 of the opposing electrically conductive sealing surfaces 116, 126 is effectively reduced.

  As can be appreciated, with this unique profile, shaping the electrically conductive sealing surfaces 116, 126 and insulators 111, 121 is more uniform, consistent, and more easily controllable adjacent tissue. An electric field distribution 135 spanning the structure is provided. Returning to FIG. 7C, it is envisioned that insulator 111 may also contact outer surface 145 in a generally tangential manner around radius “r”. As before, this profile also tends to reduce current concentration and heat spread.

  FIG. 15 also shows insulators 111, 121 and electrically conductive sealing surfaces 116, 126 that meet at an angle of 90 degrees (90 °), which insulators 111, 121 are electrically conductive sealing surfaces 116, 126. Is further positioned from the rounded edge 145. When the exposure of the edge 145 becomes very large, the formation of new and / or additional stray currents or electric fields proximal to the interfaces 129, 139 may be initiated, whereby the surfaces 116, 126 having rounded edges 145. It is envisaged that the benefits of manufacturing the product will be wasted.

  Preferably, the radii “r” and “r ′” of the outer surfaces 145, 147 of the electrically conductive sealing surface are substantially the same and are between about 10,000 inches and about 30,000 inches. However, it is contemplated that each radius “r” and “r ′” may be variously sized depending on the particular purpose to achieve the desired result.

  In some cases, it may be preferable to utilize different materials that may facilitate the manufacturing process and possibly compensate for the reduction in overall heat spread. For example, various materials are contemplated, including nylon and syndiotactic polystyrene (eg, QUESTRA® manufactured by DOW Chemical). Other materials (for example, polybutylene terephthalate (PBT), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyphthalamide (PPA), polyimide (Polyimide), polyethylene terephthalate (PET), polyamide-imide (PAI) ), Acrylic acid (PMMA), polystyrene (PS and HIPS), polyethersulfone (PES), aliphatic polyketone, acetal (POM) copolymer, polyurethane (PU and TPU), nylon with polyphenylene-oxide dispersion, and acrylonitrile Styrene acrylate) can also be utilized either alone or in combination.

  By utilizing one or more of these materials, other desired effects (eg, reduced incidence of flashover) can occur. These effects can be found in co-pending, co-pending and assigned application number 203-2657 (Johnson et al., Title of the invention "ELECTROSURGICALINSTRUMENT WHICH IS DESIGNED THE REDUCE THE INCIDENCE OF FLASHER"). Has been discussed.

  Alternatively, specific coatings may be utilized either alone or in combination with one of the above manufacturing techniques to supplement the overall thermal diffusion reduction.

  FIG. 8A shows the bipolar forceps 10 in use, where the handle members 16 and 18 are moved toward each other to apply a clamping force to the tubular tissue 150, as shown in FIGS. A seal 152 is produced. Once sealed, the tubular vessel 150 can be cut along the seal 152 to separate the tissue 150 and form a gap 154 therebetween, as shown in FIG.

  After the bipolar forceps 10 is used, or if the electrode assembly 21 is damaged, the electrode assembly 21 can be easily removed and / or replaced, and a new one in the same manner as discussed above. An electrode assembly 21 may be attached to the forceps. By making the electrode assembly 21 disposable, the electrode assembly 21 is expected to be less susceptible to damage. This is because this electrode is intended for single operation only and therefore does not require cleaning or sterilization. As a result, the functionality and consistency of the sealing components (eg, conductive surfaces 126, 116 and insulating surfaces 121, 111) ensures a uniform, good quality seal and is acceptable for heat diffusion across the tissue. Provides a definite reduction. Alternatively, the entire electrosurgical instrument can be disposable, which again exhibits a uniform, good quality seal with minimal heat spread.

  FIG. 8B shows the endoscopic bipolar instrument 100 in use, where movement of the handle assembly 128 provides a clamping force against the tubular tissue 150 to produce a seal 152 as shown in FIGS. 9-11. . As shown, shaft 109 and electrode assembly 122 are inserted through trocar 130 and cannula 132 and handle assembly 118 operates to cause tubular vessel 150 to be gripped between opposing jaw members of electrode assembly 122. . More specifically, the movable handle 118b is gradually moved toward the fixed handle 118a, which in turn causes relative movement of the jaw members from a spaced open position to a closed sealing position. The rotating member 123 allows the user to rotate the electrode assembly 122 in a position around the tubular tissue 150 prior to actuation.

  After the jaw members close around the tissue 150, the user then applies electrosurgical energy to the tissue 150 via the connection 128. By controlling the intensity, frequency and duration of the electrosurgical energy applied to the tissue 150, the user can cauterize, solidify / dry the seal with minimal collateral or thermal damage to the surrounding tissue. And / or can simply reduce or delay bleeding.

  From the foregoing and with reference to the various drawings, those skilled in the art will recognize that certain modifications can also be made to the present disclosure without departing from the scope of the present disclosure. For example, electrodes 110 and 120 face each other in parallel and are therefore preferably coplanar, but in some cases, electrodes 110 and 120 are slightly biased and face each other at their distal ends. As a result, it may be preferred that further closing forces on the handles 16 and 18 are required to deflect the electrodes in the same plane. This is expected to improve seal quality and / or consistency.

  Although it is preferred that the electrode assembly 21 comprises a housing 71 and a cover plate 80 to engage the mechanical forceps 20 therebetween, in some cases, the electrode assembly 21 engages the mechanical forceps 20. Therefore, it may be preferred that only one part (e.g. the housing 71) is manufactured.

  Nickel-based material, coating, stamping, metal injection designed to reduce the adhesion between the end effector (or its components) and the surrounding tissue during sealing or after the end effector outer surface It is anticipated that a molded article can be provided.

  Although only one embodiment of the present disclosure has been described, the present disclosure is intended to be as broad as the field permits, and the present specification is intended to be read in a similar manner. Is not to be construed as limiting. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

9 First member
11 Second member
12, 14 Elongated shaft
16, 18 Handle member
10 Bipolar forceps
20 Mechanical forceps
22, 24 End effector
111 insulator
116 Electrically conductive seal surface

Claims (7)

An electrode assembly for use with an electrosurgical instrument having opposing end effectors and a handle for effecting movement of the end effectors relative to each other, comprising:
A housing having at least one portion removably engageable with at least a portion of the electrosurgical instrument;
A pair of electrodes, each of the electrodes comprising an electrically conductive sealing surface and an insulating substrate, the electrodes being in the end effector of the electrosurgical instrument such that the electrodes are in opposing relationship to each other An electrode; and a barrier disposed about at least one outer periphery of the electrode and configured to limit heat diffusion from the electrode to surrounding tissue ; the barrier is instructions are built apart electrically conductive sealing surfaces of the electrode, the electrode assembly.   The electrode assembly of claim 1, wherein the barrier extends from an insulating substrate of the electrode.   The electrode assembly according to claim 1, wherein the barrier is attached to an electrode adjacent to the insulating substrate. Said barrier further from the electrode, extends toward the electrode opposed rather than toward the electrically conductive sealing surface, the electrode assembly according to claim 1.   The electrode of claim 1, wherein the conductive sealing surface is attached to the insulating substrate and is raised above the insulating substrate, and an outer peripheral edge of the conductive sealing surface is embedded in the insulating substrate. assembly. At least one outer peripheral edge of the conductive sealing surface includes a radius, and the insulating substrate contacts the conductive sealing surface along an adjacent edge along the outer peripheral edge, the adjacent edge being 6. The electrode assembly according to claim 5 , wherein the electrode assembly is substantially in contact with the radius. The electrode assembly of claim 1, wherein the insulating substrate is made from a material having a comparative tracking index of about 300 volts to about 600 volts.

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