JP4394880B2 - Electrosurgical instruments to reduce thermal diffusion - 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 that limit thermal diffusion to adjacent tissue structures and / or reduce this thermal diffusion and the incidence of flashover during actuation. Having an electrode assembly designed to reduce.

(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 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 opposing electrodes, which are generally placed on the inward or opposing surface of the end effector, which in turn is directed to the electrosurgical generator. And is electrically connected. Each electrode is charged to a different potential. Since tissue is a conductor of electrical energy, when an end effector is used to clamp, grasp, seal, and / or cut tissue between it, this electrical energy passes through the tissue. Can be selectively transmitted.

  Over the past few decades, the tradition of using endoscopes and endoscopic instruments (which access organs through small puncture-like incisions) to access vital organs and body cavities Increasing numbers of surgeons applaud the open method. 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 the sealing of 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 blood 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 are ruptured to 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. The paper entitled Titles on Coagulation and the Development of an Automatic Computerized Bipolar Coagulator (J. Neurosurg., Vol. 75, July 1991) is used to seal the small vessel. Yes. This article states that arteries with diameters greater than 2-2.5 mm cannot be safely coagulated. The second paper is the title Automatically Controlled Bipolar Electrocoagulation— “COA-COMP” (Neurosurg. Rev. (1984), pp. 187-190), and electrosurgery on blood vessels to avoid charring of blood vessel walls. Describes how to transmit dynamic power.

  In particular in relation to vascular sealing, two main mechanical parameters (pressure applied to the blood vessel and gap distance between the electrodes (both of which were sealed) to provide adequate sealing of large blood vessels The blood vessel thickness must be accurately 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 good sealing. 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. For example, U.S. Pat. No. 2,176,479 to Willis, U.S. Pat. Nos. 4,005,714 and 4,031,898 to Hiltebrandt, U.S. Pat. No. 5,827,274 to Boebel et al. US Pat. Nos. 5,290,287 and 5,312,433; US Pat. Nos. 4,370,980, 4,552,143, 5,026,370 and No. 116,332, US Pat. No. 5,443,463 to Stern et al., US Pat. No. 5,484,436 to Eggers et al. And US Pat. No. 5,951,549 to Richardson et al. Relates to an electrosurgical instrument for coagulating, sealing and / or cutting.

  It has been found that sealing, cutting and / or cauterizing tissue using electrosurgical instruments can cause some degree of so-called “thermal diffusion” 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 unintended or unwanted incidental damage to surrounding tissue structures adjacent to the intended treatment site. Reduce.

  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 working 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) and they are not intended .

  It has also been found that cleaning and sterilizing a number of prior art bipolar instruments is often impractical because the electrodes and / or insulators can be damaged. More specifically, an electrically insulative material (eg plastic) can be used by repeated sterilization cycles (which can ultimately lead to instrument reliability and can cause so-called “flashover”) It is known that it can be damaged or impaired. As used herein, flashover is a result of inconsistent current tracking and / or activation irregularities on the surface of an insulator or coating that can occur when the instrument is used repeatedly during surgery. Concerning the visual anomalies that occur. Simply put, flashover tends to darken the surface of the insulator and can affect the life of the instrument and / or the electrode assembly. Effects on flashover and industry standards are described in Annual Book of ASTM Standards, Vol. 10.02, symbols: D495-84; D618; D2303 and D3638 are discussed in detail.

  A number of electrosurgical instruments have been introduced that are known to solve many of the above problems associated with sealing, cutting, cauterizing and / or coagulating differently sized blood vessels. Some of these devices are copending US patent application Ser. No. 09 / 178,027, filed Oct. 23, 1998, entitled OPEN VESSEL SEALING FORCEPS WITH DISPOSABLE ELECTRODES; filed Oct. 22, 1999. US Patent Application No. 09 / 425,696, titled OPEN VESSEL SEALING FORCEPS WITH DISPOSABLE ELECTRODES; co-pending US Patent Application No. 09 / 177,950 filed October 23, 1998, titles ENDOSCOPIC BIPOLAR ELECTROSUR Copending US patent application Ser. No. 09 / 621,029, titled ENDOSC, filed July 21, PIC BIPOLAR ELECTROSURGICAL FORCEPS (the entire contents all of which are incorporated by reference herein) is described.

  Accordingly, there is a need to develop an electrosurgical instrument that includes instruments that can effectively reduce the undesirable effects of thermal diffusion across the tissue structure and can effectively reduce the incidence of flashover.

(Summary)
The present disclosure relates generally to open and / or endoscopic electrosurgical instruments, which comprise electrodes that are separated from the rest of the instrument by a uniquely designed insulating substrate and conductive surface. Electrically and thermally separated electrodes. It is envisioned that this insulating substrate geometry relative to the conductive surface geometry contributes to an overall reduction in collateral damage to adjacent tissue structures. The uniquely designed geometry of the insulating substrate combined with the chemical characteristics of the insulating substrate also contributes to a reduced incidence of flashover.

  More particularly, the present disclosure relates to an electrosurgical instrument that includes opposing end effectors and a handle for moving the end effectors relative to each other. The instrument includes a housing and a pair of electrodes. Each electrode preferably comprises a conductive surface (eg, a conductive surface that can be dimensioned for sealing, clamping and / or cutting) and an insulating substrate, the insulating substrate being an end effector and Dimensioned to be selectively engageable, so that the electrodes are in opposing relation to each other. The dimensions of this insulating substrate are different from the dimensions of the conductive surface in order to reduce thermal diffusion to adjacent tissue structures. The insulating substrate is made from a material having a comparative tracking index of about 300 volts to about 600 volts to reduce the incidence of flashover.

  Preferably, the size of the insulating substrate is different from the size of the conductive surface that not only reduces thermal diffusion to adjacent tissue structures, but can also contribute to reducing the incidence of flashover.

  In other embodiments, the insulating substrate is a conductive surface by stamping, by overmolding, by overmolding a stamped plate, and / or by overmolding a metal injection molded plate. Attached to. All of these manufacturing techniques produce an electrode having a conductive surface that is substantially surrounded by an insulating substrate. These uniquely described embodiments described herein are intended to effectively reduce thermal diffusion to adjacent tissue structures during activation and / or immediately after activation. Furthermore, certain cross-sectional biases can also contribute to a reduction in the incidence of flashover. The conductive surface may also include a pinch trim that facilitates the fixed engagement of the conductive surface to the insulating substrate and also simplifies the entire manufacturing process.

  In another embodiment, the conductive surface comprises an outer peripheral edge, the outer peripheral edge has a radius, and the insulator contacts the conductive surface along an adjacent edge, the adjacent edge being Generally, it is tangential to the radius and / or touches along the radius. Preferably, at the interface, the conductive surface is raised relative to the insulator.

  The insulating substrate can be made from a plastic or plastic-based material having a comparative tracking index of about 300 volts to about 600 volts. Preferably, the insulating substrate is a substrate made from a group of materials including: nylon, syndiotactic polystyrene (SPS), polybutylene terephthalate (PBT), polycarbonate (PC), acrylonitrile butadiene styrene ( ABS), polyphthalamide (PPA), polyimide, 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, a non-plastic insulating material (eg, ceramic) may be used instead or in combination with one or more of the above materials to facilitate the manufacturing process and heat diffusion to adjacent tissue structures Can contribute to the overall reduction of

  In another embodiment of the present disclosure, the insulative substrate of each electrode has at least one mechanical interface to engage a complementary mechanical interface disposed on a corresponding end effector of the instrument. Is provided. Preferably, the mechanical interface of the substrate may comprise a detent and the corresponding end effector mechanical interface may comprise a complementary socket to accommodate 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 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 engages a shaft and includes a pair of electrodes. Each electrode is removably engageable with a corresponding end effector and includes an electrically conductive 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 conductive surface, which effectively reduces thermal diffusion to adjacent tissue structures. This can contribute to a reduction in the occurrence rate of flashover.

  In one embodiment, the electrode assembly that engages the instrument is removable, disposable and replaceable after being used beyond its intended number of activation 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 for a single use application and the entire instrument is completely disposable after the surgery is complete.

(Detailed explanation)
By altering the composition of the electrode insulation material relative to the conductive surface, the surgeon can more easily, more easily, and more efficiently reduce heat diffusion across or adjacent to adjacent tissue. And / or it has been found that the incidence of flashover can be reduced. For the purposes herein, the term “thermal diffusion” generally refers to the transfer of heat dissipated to adjacent tissue along the periphery of a conductive solution or electrically active surface (heat conduction, heat Convection or current dissipation). This can also be referred to as “collateral damage” to adjacent tissue. The term “flashover” is simply the visible that occurs during operation as a result of inconsistent and / or irregular current tracking on the surface of the insulator that can occur if the instrument is used repeatedly during surgery. Abnormal. Flashover tends to darken the surface of the insulator and can affect the life of the instrument.

  The configuration of the insulating material surrounding the conductive surface effectively reduces current dissipation and heat dissipation to adjacent tissue regions, and generally limits current transfer to the region between opposing electrodes. ,is assumed. As noted above, this differs from dielectrically coating the outer surface of the instrument to prevent tissue “branching” at a point perpendicular to the designated site. These coatings are neither designed to reduce collateral tissue damage or thermal diffusion to adjacent tissue (tissues that exist along the tissue activation plane) and are intended to reduce this There is not.

  More specifically, altering the insulator geometry relative to the conductive surface is intended to alter the electrical path and thereby affect heat diffusion / collateral damage to adjacent tissue structures. The Preferably, the shape of the insulating substrate also separates two electrically opposite polarities (ie, electrodes) from each other, thereby forming an unintended bridge or path for current transfer by tissue or tissue fluid. Reduce the chances of getting. In other words, as described in more detail below, the insulator and conductive surface are preferably dimensioned such that current is concentrated between opposing conductive surfaces.

  One way to reduce the incidence of flashover is to change the shape of the insulator with respect to a conductive surface that effectively increases the total distance the current must travel along a given electrical path. Intended. It is also envisioned that manufacturing an insulating substrate from a specific material having specific characteristics will similarly reduce the incidence of flashover during operation.

  1-3, by way of example, a bipolar forceps 10 for use in conjunction with an open surgical procedure is shown, which includes a mechanical forceps 20 and an electrode assembly 21. In the drawings and the following description, the term “proximal” conventionally 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, 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 22 and 24 are movable relative to each other in response 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 disposed in a spaced relationship relative to each other with respect to the closed position, wherein the end effectors 22 and 24 seal, cut or cut the tubular vessel 150 therebetween. Incorporate for gripping (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. It is also possible that the forceps 10 can only be designed 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). ,is assumed.

  Referring most to 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, The interface is sized to removably engage a portion of the 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. Sized to accommodate the 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 can be a disposable electrode assembly. 21 is contemplated.

  In some cases, manufacturing the mechanical interface 41 along another side of the jaw member 44 and engaging the complementary mechanical interface of the electrode assembly 21 in a different manner (eg, from that side) It may be preferable. 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 a complementary guide pin 124 disposed on the electrode 120 of the electrode assembly 21. Is dimensioned to accept

  End effector 22 includes a second or lower jaw member 42 having an inward surface 47 opposite to inward surface 45. Preferably, the jaw members 42 and 44 are dimensioned approximately symmetrically, but in some cases it is preferable to produce two asymmetric jaw members 42 and 44 depending on the particular purpose. possible. In exactly the same manner as described above with respect to the jaw member 44, the jaw member 42 also includes a plurality of mechanical interfaces or sockets 43 disposed thereon, which, as described below, are electrodes 110 of the electrode assembly 21. Sized to removably engage the complementary portion 112 disposed thereon. 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 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 envisaged that angling the end effector 22, 24 with respect to the distal end 19, 17 is advantageous for two reasons: 1) Depending on the angle of the end effector, jaw members and electrodes, Apply a greater constant pressure for cutting and / or apply a parallel and more uniform tissue thickness for sealing purposes, and 2) a thicker proximal portion of this electrode, eg, 110 ( As a result of the taper along the width “W”), it does not yield to bending due to the reaction force of the tissue 150. 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 evaluation) and evaluation of activation.

  Preferably, the shaft members 12 and 14 of the mechanical forceps 20 apply a particular desired force to the opposing inward surfaces of the jaw members 22 and 24, respectively, when clamped or during sealing and / or cutting. Designed to communicate. In particular, since the shaft members 12 and 14 work together effectively in a spring-like manner (ie, bend like a spring), the length, width, height and deflection of the shaft members 12 and 14 are opposite. This directly affects the total transmission force applied to the 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. This is particularly relevant during sealing.

  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 align the movement of two handles to separate units, which in turn moves 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, one embodiment of an electrosurgical instrument includes an electrode assembly 21 that operates in combination with a mechanical forceps 20. Designed. 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 78 is dimensioned 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 pivot the mechanical forceps 20. It is dimensioned to encompass at least a portion of point 25 and distal end 19. The electrode assembly 21 may be manufactured to engage 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, handle 18, shaft 14, pivot point 25, and a portion of distal end 19 are all sized to fit within corresponding channels disposed within 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 point 25 and a portion of distal end 19. It is such a dimension.

  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 a pivot point of the mechanical forceps 20. 25 and the distal end 19 are designed to surround. Preferably, handle 18, shaft 14, pivot point 25 and distal end 19 are all corresponding channels (not shown) disposed in cover plate 80 in a manner similar to that described above with respect to housing 71. Dimensions that fit inside.

  As best shown with respect to FIGS. 3 and 4, the housing 71 and the cover plate 80 are sized to cover and engage one another over the first member (eg, 11) of the mechanical forceps 20. The first member 11 and its respective component parts (eg, handle 18, shaft 14, distal end 19 and pivot point 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 placed in the housing 71 with a mating mechanical interface placed on or in the cover plate 80 Is assumed.

  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. It is bifurcated 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. Electrodes 110 and 120 may be attached 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. . As mentioned above, the inventive concept disclosed herein also does not comprise a selectively removable electrode assembly, but rather has an integrally associated electrode disposed thereon. It may relate to an electrosurgical instrument comprising an end effector.

  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 preferable to surround

  This arrangement of 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 preferable to extend the wires 60 and 62 to an electrosurgical generator (not shown). possible.

  As best shown in FIG. 6, the electrode 120 comprises a conductive surface 126 and an electrically insulating substrate 121, which can be snap fit engaged or some other assembly method (eg, slide fit). , By stamping 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 isolates the current, but also aligns the electrodes 120, both of which contribute to reduced thermal diffusion across the tissue and reduced incidence of flashover. 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 produces an electrode 120 as compared to the conventional manufacturing technique (resulting in a height of “h1”) (FIG. 7B). Is reduced in overall height “h2” (FIG. 7C). The lower height “h2” allows the user access to smaller areas within the body and facilitates operation around more sensitive tissue areas.

  Furthermore, it is contemplated that the overmolding technique provides greater insulation along the sides of the conductive surface that also reduces thermal diffusion due to the electrode not contacting the tissue very much. In this way (ie, the conductive surface area is reduced), by aligning the dimensions of the substrate (eg, 121) and the electrode 120, the intended area (which may be in contact with the outer edge of the electrode 120). It is envisaged that the current is not limited to the tissue outside it, but is limited (ie, concentrated) to the intended area (see FIG. 7B). Providing greater insulation along the sides of the conductive surface can also effectively reduce the incidence of flashover.

  Preferably, the substrate 121 comprises a plurality of bifurcated detents 122 that are compressed during insertion into the socket 41 and that are configured to expand and removably engage the socket 41 after insertion. The snap-fit engagement of electrode 120 and jaw member 44 is envisioned to meet a wide range of manufacturing tolerances. The substrate 121 also includes alignment pins or guide pins 124. The pin 124 is sized to engage the opening 67 of the jaw member 44. The slide fit technique is also described with respect to co-pending US Patent Application No. 203-2348 CIP2PCT (Tezlaff et al.), The entire contents of which are hereby incorporated by reference. Such a slide fit technique is contemplated.

  Conductive surface 126 engages distal end 90 of prong 105 of electrode assembly 21 and electrically engages a corresponding wire connector attached to wire 60 located within electrode assembly 21. A designed wire crimp 145 is provided. The conductive surface 126 also includes an opposing surface 125 designed to pass an electrosurgical current through the tubular container or tissue 150 when held against the tubular container or tissue 150. It is envisioned that the conductive surface 126 (116) can be dimensioned as a sealing surface, a clamping surface, and / or a shearing or cutting surface, depending on the particular purpose.

  Electrode 110 includes similar elements and materials to insulate and conduct electrosurgical current to tissue 150. More specifically, the electrode 110 includes a conductive surface 116 and an electrically insulating substrate 111. The surface and substrate are attached to each other by one of the assembly methods described above. The substrate 111 includes a plurality of detents 112 that are sized to engage corresponding sockets 43 and openings 65 located on the jaw member 42. The conductive surface 116 includes an extension 155 having a wire crimp 119 that engages the distal end 91 of the prong 103 and electrically engages a corresponding wire connector attached to a wire 62 located in the housing 71. . The conductive surface 116 also includes a facing surface 115 that conducts an electrosurgical current through the tubular container or tissue 150 when held against the tubular container or tissue 150. Electrodes 110 and 120 may be formed as one piece and may have similar components and / or dimensions for insulating and energizing electrical energy in a manner that effectively reduces the incidence of thermal diffusion and flashover. . The stray current can be further limited by casting the forceps and / or manufacturing the forceps using a non-conductive material and / or coating the edges of the electrodes 110 and 120 with an insulating coating.

  As noted above, it is envisioned that flashover and thermal diffusion can be reduced by changing the physical dimensions (ie, shape / shape) of the insulator and / or the chemical characteristics of the insulator. In particular, with respect to thermal diffusion, it is envisioned that manufacturing electrodes 110 and 120 in this manner reduces thermal diffusion and stray currents that can flow to the electrosurgical instrument. More specifically, changing the shape of insulator 111 as compared to conductive surface 116 also insulates two opposing poles during operation, thereby allowing tissue or fluid to flow to surrounding tissue. Reduce the possibility of crossing the path of stray current. With respect to flashover, changing the shape of insulator 111 and / or the conductive surface creates a longer path of current flowing over insulator 111 before flashover occurs.

  For example, as best shown in a comparison of FIG. 7B (prior art) to the newly disclosed FIGS. 7C, 7D, 14A and 14B, the substrates 111, 121 extend along a width “W”. As a result, the width of the insulating substrate (eg, 111) is greater than the width of the conductive surface (eg, 116). It is envisioned that these conductive surface 116 and insulator 111 configurations can be achieved by various manufacturing techniques (eg, stamping and / or metal injection molding overmolding). Stamping is defined herein to include virtually any pressure operation known in the industry. These operations include, but are not limited to: blanking, shearing, hot or cold forming, stretching, bending and coining. Other manufacturing techniques can also be used to achieve similar conductive surface 116 and insulator 111 configurations that effectively reduce heat diffusion to adjacent tissue.

  As best seen in FIG. 7D, the electrode 116 may also include a pinch trim 131 that facilitates securing, integral engagement of the insulator 111 and the conductive surface 116 during the assembly and / or manufacturing process. FIG. 7E illustrates another embodiment of the present disclosure. Here, the compliant material 161 is disposed around the outer periphery of the conductive surfaces 116 and 126 and the substrates 111 and 121. It is envisioned that the compliant material 161 acts as a mechanical barrier by limiting the heat and vapor generated from the 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 the conductive surfaces 116, 126 raised relative to the insulating coating or insulator 111,121. Preferably, the conductive surfaces 116, 126 are rounded or curved at the corners, thereby reducing current concentration and stray current dissipation to the surrounding tissue structure. It is envisioned that the insulators 111, 121 and the conductive surfaces 116, 126 can be sized to contact at or approximately along the boundary or bonded longitudinally oriented edges 129, 139. The These edges are rounded at the corners to reduce current density 141 and current dissipation near interfaces 129, 139 and opposing conductive surfaces 116, 126.

  For example, and by way of example, FIGS. 12 and 13A-13C show other electrode 110, 120 configurations known in the prior art. FIG. 12 shows an example of non-insulated (ie, without insulators 111, 121) counter electrodes 110, 120 during operation, illustrating the electric field distribution 135 generated from the counter conductive surfaces 116, 126 (the current is Are known to flow perpendicular to these electric field lines). As can be appreciated, the electric field 135 occurs well beyond the intended treatment site, which can contribute to increased lateral tissue damage and possible cuts.

  By providing insulators 111, 121 in contact with conductive surfaces 116, 126, as shown in FIGS. 13A-13C, the electric field distribution 135 can be greatly reduced. However, as the enlarged views of FIGS. 13B and 13C show, current density 141 tends to occur between opposing conductive surfaces 116, 126 at or near interfaces 129, 139. This current density 141 can also have a negative effect, possibly leading to tissue cutting or tissue penetration to the electrode or conductive surface at this site.

  14A-15 illustrate various electrode 110, 120 configurations in accordance with the present disclosure, where the conductive surfaces 116, 126 and insulators 111, 121 have a current density 141 between the opposing electrodes 110, 120. Designed to reduce the amount. More specifically, FIGS. 14A and 14B show a pair of raised conductive surfaces 116, 126 (relative to insulators 111, 121) that have radii “r” and “r ′”, respectively. The outer periphery 145,147 is provided. Preferably, insulators 111, 121 face perimeters 145, 147 and form adjacent edges or interfaces 129, 139 along radii "r" and "r '", respectively. By configuring the electrodes 110, 120 in this manner, it is contemplated that the current density 141 between the outer perimeters 145, 147 of the opposing conductive surfaces 116, 126 is effectively reduced. As can be appreciated, by configuring the conductive surfaces 116, 126 and insulators 111, 121 with this unique profile, a more uniform, consistent, and more easily controllable electric field across adjacent tissue structures. A distribution 135 is further provided. Returning to FIG. 7C, it is anticipated that the insulator 111 may also face the outer periphery 145 in a manner that generally touches about the radius “r”. Again, this profile also tends to reduce current density and thermal diffusion, and can also contribute to reducing the occurrence of flashover.

  FIG. 15 also illustrates that the insulators 111, 121 and the conductive surface 116 face at an angle of 90 °, but the insulators 111, 121 are located far from the radiused edges 145 of the conductive surfaces 116, 126. , 126. If the exposure of the edge 145 is too great, new and / or additional stray currents or electric fields may begin to form near the interfaces 129, 139, thereby benefiting the manufacture of the surfaces 116, 126 with rounded edges 145. Expected to be zero.

  Preferably, the radii “r” and “r ′” of the outer perimeters 145, 147 of the conductive surface are approximately the same and are from about 10 / 1000th to about 30 / 1000th of an inch. However, it is contemplated that each radius “r” and “r ′” may be sized differently depending on the particular purpose or to achieve the desired result.

  While the geometric modification of the insulator 111 relative to the conductive sealing surface 116 is contemplated to reduce the occurrence of flashover and thermal diffusion, in some cases, to reduce flashover and thermal diffusion, It may be preferable to simply use different materials for the insulator. For example, and in particular with respect to flashover, all plastics are known to have different resistances to flashover, which is usually measured using a Comparative Tracking Index (CTI). The The CTI value required to resist flashover is typically determined in part by the maximum voltage of the electrosurgical generator, but other parameters (eg, frequency) are also typically Bring a flashover.

  It has been found that instead of or in addition to changing the geometry of insulator 111 and / or conductive surface 116, plastic insulation having a CTI value of about 300 to about 600 volts can be used. Examples of high CTI materials include nylon and syndiotactic polystyrene (eg, QUESTRA® manufactured by DOW Chemical). Other materials (for example, nylon, syndiotactic polystyrene (SPS), polybutylene terephthalate (PBT), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyphthalamide (PPA), polymide (Polyimide), polyethylene terephthalate ( PET, polyamide-imide (PAI), acrylic (PMMA), polystyrene (PS and HIPS), polyethersulfone (PES), aliphatic polyketone, acetal (POM) copolymer, polyurethane (PU and TPU), polyphenylene oxide dispersed Nylon as well as acrylonitrile styrene acrylate) can also be utilized to reduce flashover, either alone or in combination.

  However, in some cases, changing the geometry of both insulator 111 and / or conductive surface 116 and / or utilizing plastic insulation that does not have a CIT value of about 300 to about 600 volts It may be preferable to do. Alternatively, specific coatings can be utilized either alone or in combination with one of the above manufacturing techniques to reduce flashover and thermal diffusion.

  FIG. 8A shows one embodiment of the present disclosure, which shows the bipolar forceps 10 in use, where the handle members 16 and 18 are moved closer together to exert a clamping force on the tubular tissue 150. Apply and produce a seal 152 as shown in FIGS. 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. Alternatively, the conductive surfaces 116, 126, electrodes 110, 120 and / or jaw members 42, 44 are dimensioned as shear surfaces that effectively cut tissue when the jaw members 42, 44 are moved relative to one another. Can be done.

  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 in the same manner as described above, the new electrode assembly 21 can be replaced. Can be attached to 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 components (eg, conductive surfaces 126, 116 and insulating surfaces 121, 111) ensures a reliable reduction in heat diffusion across the tissue and / or the occurrence of flashover. Decrease rate. Alternatively, the entire electrosurgical instrument can be disposable, which can again contribute to a reduction in heat diffusion across the tissue and / or reduce the incidence of flashover.

  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. Produce. As shown, shaft 109 and electrode assembly 122 are inserted through trocar 130 and cannula 132, and handle assembly 118 is actuated to grip tubular vessel 150 between opposing jaw members of electrode assembly 122. The 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 operating position. The rotating member 123 allows the user to rotate the electrode assembly 122 to a position around the tubular tissue 150 prior to actuation. Again, conductive surfaces 116, 126, electrodes 110, 120 and / or jaw members 42, 44 are dimensioned as shear surfaces that effectively cut tissue when jaw members 42, 44 are moved relative to one another. Can be done.

  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 with minimal incidental or thermal damage to the surrounding tissue and with a minimal flashover rate. It can either cauterize, solidify / dry, seal, cut, and / or 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, it is preferred that electrodes 110 and 120 face each other in parallel and therefore face in the same plane, but in some cases, electrodes 110 and 120 are slightly slightly facing each other at their distal ends. It may be preferred that additional closing forces on the handles 16 and 18 are required to bias and consequently deflect the electrodes in the same plane.

  Nickel-based materials, coatings, stamping, metal injection molded parts where the outer surface of the end effector is designed to reduce contact between the end effector (or its components) and the surrounding tissue during actuation It is envisaged that

  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.

FIG. 1 is a perspective view of an open electrosurgical instrument according to one embodiment of the present disclosure. FIG. 2 is an enlarged perspective view of the distal end of the electrosurgical instrument shown in FIG. FIG. 3 is a perspective view of the electrosurgical instrument shown in FIG. 1, wherein the parts are separated. 4 is an enlarged side view of the electrode assembly of FIG. 1, which is shown without a cover plate. FIG. 5 is an enlarged perspective view of the distal end of the electrode assembly of FIG. FIG. 6 is a perspective view of the upper electrode of the electrode assembly of FIG. 5, where the parts are separated. FIG. 7A is a perspective view of the bottom electrode of the electrode assembly of FIG. 5, where the parts are separated. FIG. 7B is a cross section of a prior art electrode configuration in which the electrodes extend on the sides of the insulator. FIG. 7C is a cross section of an electrode having an insulator that extends beyond the side of a radiused electrode. FIG. 7D is a cross section of an overmolded stamp electrode configuration showing an insulator that captures a pinch trim depending from the conductive surface. FIG. 7E is a cross-section of the electrode configuration showing a compliant barrier that controls / adjusts the heat dissipated from the conductive surfaces disposed around the perimeter of the opposing electrode and insulator. FIG. 8A is a perspective view of the open forceps of the present disclosure showing the operational movement of an electrosurgical instrument around a tubular vessel. FIG. 8B is a perspective view of the endoscopic version of the present disclosure, illustrating the operational movement of the instrument. FIG. 9 is an enlarged partial perspective view of a sealing portion of a tubular blood vessel. 10 is a longitudinal cross-section of the sealing site taken along line 10-10 of FIG. 11 is a longitudinal cross-section of the sealing site of FIG. 9 after separation of the tubular blood vessel. FIG. 12 is a contour plot showing the dissipation of electrosurgical current across tissue using an electrode without insulator. FIG. 13A is a contour plot showing the dissipation of electrosurgical current across tissue using an electrode having a flash insulator. 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 surface. FIG. 13C is an enlarged plot of the electric field magnitude of the electrode configuration of FIG. 13A, showing the current density and relative of the electrosurgical electric field distribution at the adjacent edge or interface between the insulator and the conductive surface. Indicates dissipation. FIG. 14A is a contour plot showing the dissipation of electrosurgical current across tissue using an electrode having a protruding conductive surface and a semicircular interface between the conductive surface and the insulator. FIG. 14B is an expanded isotherm plot of FIG. 14A showing the current density and relative dissipation of the electrosurgical current at the interface between the adjacent edge or insulator and the conductive surface. 14C is an enlarged plot of the electric field magnitude for the electrode configuration of FIG. 14A, with the current density and relative dissipation of the electrosurgical electric field distribution at the adjacent edge or interface between the insulator and the conductive surface. Indicates. FIG. 15 is a contour plot showing the dissipation of electrosurgical current across tissue using an electrode having a protruding conductive surface and a 90 ° interface between the conductive surface and insulation.

Claims (9)

An instrument for sealing a tube or tissue, the instrument comprising:
housing;
A handle for causing movement of the end effector relative to each other; and a pair of electrodes, each electrode comprising a conductive surface and an insulating substrate having a radius r and a rounded corner The dimensions of the insulating substrate are different from the dimensions of the conductive surface to reduce thermal diffusion to adjacent tissue structures, and the insulating substrate is approximately about to reduce the incidence of flashover. A pair of electrodes made from a material having a comparative tracking index of 300 volts to about 600 volts;
With
Insulating Enmotozai extends beyond the periphery of the conductive surface, forming a contact surfaces to track along the radius r, and the conductive surface is raised relative to the insulating substrate It is, instrument. Wherein the insulating substrate is nylon, syndiotactic polystyrene, polybutylene terephthalate, polycarbonate, acrylonitrile butadiene styrene, polyphthalamide, poly Lee bromide, polyethylene terephthalate, polyamide - imide, acrylic, polystyrene, polyether sulfone, polyketone, The device of claim 1 selected from the group consisting of acetal copolymer, polyurethane, nylon dispersed with polyphenylene oxide, and acrylonitrile styrene acrylate.   The instrument of claim 1, wherein the insulating substrate is attached to the conductive surface by overmolding a stamped plate.   The instrument of claim 1, wherein the insulating substrate is attached to the conductive surface by overmolding a metal injection molded plate.   The instrument of claim 1, wherein the conductive surface of at least one electrode comprises a pinch trim. The insulating base material of each of said electrodes, for engaging a corresponding disposed in the end effector complementarity mechanical contact surfaces of the instrument, comprises at least one mechanical contact surface, according to claim 1 Appliances. The instrument of claim 1, wherein the conductive surfaces of the pair of electrodes cooperate to seal tissue. The instrument of claim 1, wherein the conductive surfaces of the pair of electrodes comprise shearing surfaces that cooperate to cut tissue. An instrument for sealing a tube or tissue, the instrument comprising:
housing;
A handle for effecting movement of the end effector relative to each other; and a pair of electrodes, each of the electrodes having a first geometry and an end rounded at a radius r at a corner An electrode having an insulating substrate having a surface and a second geometric shape, wherein the electrode is integrally coupled with the end effector of the instrument such that the electrodes are in opposing relationship to each other;
With
Wherein the second geometry of the insulating substrate is different from the first geometry of the conductive surface to reduce thermal diffusion to adjacent tissue structures; and The insulating substrate is a device made of a material having a comparative tracking index of about 300 volts to about 600 volts to reduce the incidence of flashover,
Insulating Enmotozai extends beyond the periphery of the conductive surface, forming a contact surfaces to track along the radius r, and the conductive surface is not raised relative to the insulating substrate Equipment.