JP2009101220A - Electrosurgical instrument with reduced flashover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrosurgical instrument with reduced flashover. <P>SOLUTION: The electrosurgical instrument includes end effectors facing each other, and handles to move the end effectors. An electrode assembly is provided to be usable in combination with the electrosurgical instrument. The electrode assembly includes a housing comprising a component that is detachably engaged with the electrosurgical instrument, and a pair of electrodes each having a conductive seal surface and insulation base material. The electrodes are detachably engaged with the end effectors of the electrosurgical instrument, so that the electrodes exist in such a relation as to face each other. The insulation base material is made of a plastic material having a high comparative tracking index for reducing the occurrence ratio of flashover. <P>COPYRIGHT: (C)2009,JPO&INPIT

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, the forceps having an electrode assembly designed to reduce the incidence of flashover.

(Technical field)
A hemostatic forceps or forceps is a simple pliers-like tool that uses mechanical movements between its jaws to tighten tissue, generally to grasp, dissect and / or clamp tissue 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 opposite electrodes, which are generally placed on the inner sheath or opposite surface of the end effector, which in turn passes to the electrosurgical generator. Electrically 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) An increasing number of surgeons praise the open methods. The endoscopic instrument is inserted into the patient through a cannula or port (made with a trocar). Typical sizes for cannulas range from 3 millimeters to 12 millimeters. Although smaller cannulas are usually preferred, as can be appreciated, this is ultimately designed for instrument manufacturers who must find a way to produce a surgical instrument that fits through the cannula. The above challenges are shown.

  Certain endoscopic 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 seals. For purposes herein, the term “coagulation” is defined as the process by which tissue cells rupture and dry dry tissue. The term “vascular seal” is defined as the process of liquefying the collagen in a tissue so that the tissue crosslinks and reforms into a fused mass. Therefore, 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. Non-patent document 1 describes a bipolar coagulation device 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, which is a non-patent document 2 , describes a method of transmitting electrosurgical force to a blood vessel so as to avoid burning of the blood vessel wall.

  Two key mechanical parameters (pressure applied to the vessel and gap distance between electrodes (both of which affect the thickness of the sealed vessel)) to provide a proper seal for large vessels It must be precisely 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 of Williams, Patent Document 2 and Patent Document 3 of Hiltebrandt, Patent Document 4 of Boebel et al . , Patent Document 5 and Patent Document 6 , Patent Document 7 of Lottick, Patent Document 8 and Patent Document 9 and Patent Document 10 Patent Document 13 Patent Document 12 and Richardson et Stern et al in Patent Document 11, Eggers et al., all, coagulating blood vessels or tissue, to electrosurgical instrument for sealing and / or 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 seal purposes. Other instruments generally rely only on clamping pressure to obtain the proper seal 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 sealed tissue by controlling only the clamping pressure for either of the following two reasons: 1) Application If the applied force is too great, the two poles may touch and energy may not transfer 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-quality seal is produced.

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 insulating material (eg, plastic) can result in repeated sterilization cycles (which can ultimately result in seal quality and consistency and cause so-called “flashover”) It is known that it can be damaged or impaired by 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. Flashover tends to darken the surface of the insulator but does not provide seal quality. However, it can result in the lifetime of the instrument and / or electrode assembly. Effects on flashover and industrial standards are discussed in detail in Non-Patent Document 3 .

  Several manufacturers have introduced a variety of electrosurgical instruments that can solve many of the above problems related to sealing, cutting, cauterizing and / or coagulating differently sized blood vessels. Are known. Some of these devices are co-pending US patent application Ser. No. 09 / 178,027, filed Oct. 23, 1998, entitled OPEN VESSEL SEALING FORCEPS WITH DISPOSABLE ELECTRODES; US Patent Application No. 09 / 425,696, entitled OPEN VESSEL SEALING FORCEPS WITH DISPOSABLE ELECTRODES; US Patent Application No. 09 / 177,950, filed October 23, 1998, titled ENDOSCOPIC BIPOLAR ELECTROSURIC US patent application Ser. No. 09 / 621,029, filed July 21, 2011, titled ENDOSC PIC BIPOLAR 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

Studies on Coagulation and the Development of an Automatic Computerized Bipolar Coalulator (J. Neurosurg., Vol. 75, July 1991) Automatically Controlled Bipolar Electrocoagulation— “COA-COM” (Neurosurge. Rev. (1984), pp. 187-190) Annual Book of ASTM Standards, Vol. 10.02, symbols: D495-84; D618; D2303 and D3638

  However, since many electrosurgical instruments are designed to be reused during subsequent operations, repeated use of the electrosurgical instrument after sterilization can lead to consistency on the insulator surface that can cause flashover. Current tracking and / or startup irregularities may occur. Activation irregularities can also be on or on the insulator surface of disposable and / or partially disposable instruments if the instrument is used beyond the recommended number of activation cycles during the work process. Can occur in the vicinity.

  Accordingly, there is a need to develop an electrosurgical instrument that can seal blood vessels and tissues consistently and effectively, and that effectively reduces the incidence of flashover.

(Summary)
The present disclosure relates generally to open and / or endoscopic electrosurgical instruments that comprise a removable electrode assembly that is designed and / or uniquely designed with a unique insulating substrate. It has electrodes that are electrically and thermally separated from the rest of the instrument by an insulating substrate and a conductive surface. Both the geometry of this insulating substrate (relative to the geometry of the conductive surface) and / or the type of insulating material used can contribute to the overall reduction in the incidence of flashover. is assumed.

  More particularly, the present disclosure relates to an electrode assembly for use with an electrosurgical instrument, which includes opposing end effectors and a handle for moving the end effectors relative to each other. The assembly includes a housing that includes at least a portion removably engageable with at least a portion of an electrosurgical instrument (eg, a handle, an end effector, a pivot, a shaft, etc.) and a pair of electrodes. Have. 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 in opposing relation to each other. To position.

  In one embodiment, the size of the insulating substrate is different from the size of the conductive sealing surface that effectively reduces the incidence of flashover.

  In another embodiment, the insulating substrate of each electrode includes a mechanical interface to engage a complementary mechanical interface disposed on a corresponding end effector of the electrosurgical instrument. For example, the substrate mechanical interface may comprise a detent and the corresponding end effector mechanical interface may comprise a complementary socket to accommodate the detent.

  Preferably, the insulating substrate is a conductive sealing surface by stamping, by overmolding, by overmolding a stamped sealing plate and / or by overmolding a metal injection molded sealing plate. Attached to. In another embodiment, the conductive sealing surface comprises a pinch trim and the insulating substrate extends beyond the periphery of the conductive sealing surface. All of these manufacturing techniques are intended to effectively reduce the incidence of flashover during operation.

  In another embodiment of the present disclosure, the insulating substrate is made from a 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), 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.

  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 positioned at an angle alpha (α) relative to the distal end of the shaft of the electrosurgical instrument. Preferably, this angle is from about 50 ° 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 an electrically 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 the incidence of flashover during instrument operation. Let

Preferably, the electrode assembly is removable, disposable and replaceable after use 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 engageable with at least a portion of the instrument;
A pair of electrodes, each of which includes a conductive sealing surface and an insulating substrate, wherein the electrodes are releasably engaged with the end effector of the instrument such that they are in opposing relationship to each other. Possible electrodes,
Wherein 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.
(Item 2)
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 3)
Item 2. The electrode assembly of item 1, wherein the size of the insulating substrate is different from the size of the conductive sealing surface to reduce the incidence of flashover.
(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 item 1, wherein the electrode assembly is disposable.
(Item 7)
7. The electrode assembly of item 6, 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)
The mechanical interface of the at least one 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)
Item 2. The electrode assembly of item 1, wherein the housing comprises a bifurcated distal end, the distal end forms two prongs, and each electrode is removably attached to one of the prongs. .
(Item 10)
The electrode assembly of claim 1, further comprising at least one ratchet, wherein the ratchet engages a complementary mechanical interface to maintain a desired closing force between opposing electrodes.
(Item 11)
The electrode assembly according to item 1, wherein at least one of the opposing end effector and the opposing electrode is tapered.
(Item 12)
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 13)
12. The electrode assembly of item 11, wherein the angle is from about 60 degrees to about 70 degrees.
(Item 14)
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 15)
An electrode assembly for use with an electrosurgical instrument, the electrosurgical instrument having a handle and at least one shaft for effecting movement of a pair of opposing end effectors relative to each other, the electrode assembly comprising: ,Less than:
A housing having at least one portion removably engageable with at least one of the handle and the shaft; and
A pair of electrodes, each of said electrodes having a conductive sealing surface having a first geometric shape and an insulating substrate having a second geometric shape, said electrodes being relative to each other An electrode removably engageable with the end effector of the instrument in an opposing relationship;
Wherein the second geometry of the insulating substrate is different from the first geometry of the sealing surface to reduce the incidence of flashover .
(Item 16)
16. The electrode assembly of item 15, 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 17)
The electrode assembly of claim 16, wherein the insulating substrate is made from a material having a comparative tracking index of about 300 volts to about 600 volts.
(Item 18)
An electrode assembly for use with a disposable electrosurgical instrument, the disposable electrosurgical instrument having a handle and at least one shaft for effecting movement of a pair of opposing end effectors relative to each other; The electrode assembly is as follows:
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 geometry of the insulating substrate is different from the first geometry of the conductive sealing surface to reduce the incidence of flashover, 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 the distal end 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 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. 8A is a perspective view of the forceps of the present disclosure showing the manipulating motion of the forceps for sealing a tubular blood 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.

(Detailed explanation)
It has been found that by changing the electrode insulation material, the surgeon can consistently and easily perform a high quality seal, reducing the possibility of so-called “flashover”. Flashover is simply a viewing angle abnormality that occurs during sealing as a result of inconsistent and / or irregular current tracking across the insulator surface that can occur if the instrument is used repeatedly during surgery . Flashover tends to char the insulator surface but is not known to affect the quality of the seal. However, flashover can affect the life of the instrument.

  One way to reduce the incidence of flashover is to change the insulator geometry to a conductive sealing surface that effectively increases the overall distance that the current must travel along a given electrical path. It is contemplated to be a change. It is also contemplated that manufacturing an insulating substrate from a specific material having specific characteristics will similarly reduce the incidence of flashover.

  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, 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, end effectors 22, 24 (and then jaw members 42 and 44 and corresponding electrodes 110 and 120) are disposed at an angle alpha (α) relative to distal ends 19, 17 (FIG. 2). reference). This angle alpha (α) is contemplated to be in the range of about 50 ° to about 70 ° relative to the distal ends 19,17.

  It is envisioned that the angling of the end effector 22, 24 at an angle alpha (α) relative to the distal end 19, 17 may be advantageous for the following two reasons: 1) The angle of the end effector, jaw members and electrodes is Apply a more constant pressure parallel to a constant tissue thickness; and 2) When the proximal portion of the electrode (eg, 110) becomes thicker (as a result of a taper along the width “W”), the tissue 150 Can resist bending due to the reaction force. The “W” taper of electrode 110 (FIG. 2) calculates a mechanical advantage variation from the distal end to the proximal end of the electrode 110, and thereby the electrode 110. Determined by adjusting the width. Sizing the end effector 22, 24 at an angle of about 50 ° to about 70 ° provides access to certain anatomical structures associated with prostatectomy and cystotomy (eg, dorsal vein complex and lateral stem) However, it is contemplated that this structure is preferred for sealing.

  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 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).

  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 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. 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 assemblies 21 as described below. Sized to removably engage a complementary portion 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, shaft members 12 and 14 of mechanical forceps 20 are designed to transmit certain desired forces to the opposing inward surfaces of jaw members 22 and 24, respectively, when clamped. 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 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, 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 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. Dimensioned to surround at least a portion of shaft 25 and distal end 19. The electrode assembly 21 can 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, the handle 18, the shaft 14, the pivot axis 25, and a portion of the distal end 19 are all sized to fit within corresponding channels 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 shaft 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 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 axis 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. Dimensions that fit inside.

  As best shown with respect to FIGS. 3 and 4, the housing 71 and the cover plate 80 are dimensioned to engage each other on the first member (eg, 11) of the mechanical forceps 20, and as a result. 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 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. 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. Electrodes 110 and 120 may be attached to ends 91 and 90 in any known manner (eg, friction 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 preferable 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 preferable to extend the wires 60 and 62 to an electrosurgical generator (not shown). possible.

  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). Are attached to 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 isolates the current, but also aligns the electrodes 120, both of which contribute to reduced seal quality, consistency and 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 in comparison with FIGS. 7B and 7C, the overmolding manufacturing technique produces a height of “h1” (FIG. 7B) compared to the conventional manufacturing technique (FIG. 7B). The overall height “h2” (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. Furthermore, overmolding techniques provide more insulation along the sides of the conductive surface, which is also intended to effectively reduce the occurrence of flashover.

  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 also contemplates the slide-fit technique described with reference to co-pending US application number 203-2348CIP2PCT, for example by Tetlaff et al., The entirety of which is hereby incorporated herein by reference. Is incorporated by reference.

  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 connector attached to the wire 60 disposed within the electrode assembly. Electrically engage with. The sealing surface 126 also includes an opposing surface 125 that is designed to transmit an electrosurgical current to the tubular vessel or tissue when held against the tubular vessel or tissue 150. Is done.

  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 a conductive sealing surface 116 and an electrically insulating substrate 111 that are attached to each other 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 that is 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. It is contemplated that the 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 reduces the occurrence of flashover.

  As described above, flashover is a material used to manufacture insulators by changing the physical or chemical properties of the insulator and electrode (eg, by changing the outer shape / shape of the insulator) It is envisaged that it can be reduced and / or eliminated by changing the type of and / or by coating the insulator with a different material. By modifying the contour of insulator 111 and / or conductive surface 116, a longer path of current is created to travel over insulator 111 before flashover occurs. For example, as best shown by comparing FIG. 7B (prior art) to the newly disclosed FIGS. 7C and 7D, the substrates 111, 121 are designed to stretch with a width “W” (FIG. 2). As a result, the width of the insulating substrate (eg, 111) exceeds the width of the conductive seal surface 116. It is envisioned that manufacturing these conductive sealing surface 116 and insulator 111 configurations can be accomplished 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.

  As best shown in FIG. 7D, the conductive sealing surface 116 may include a pinch trim 131 that secures the insulator and the conductive sealing surface 116 during the assembly and / or manufacturing process. Easy integral engagement. It is envisioned that fabrication of electrodes 110 and 120 in this manner reduces the occurrence of flashover. Other manufacturing techniques can also be used to achieve a similar conductive sealing surface 116 and insulator 111 configuration, which effectively reduces the occurrence of flashover.

  While it is contemplated that altering the outer shape of the insulator 111 relative to the conductive sealing surface 116 will reduce the occurrence of flashover, in some cases, different materials may be used for the insulator to reduce flashover. It may be preferable to use it. For example, it is known that all plastics have different resistance to flashover, which is typically measured using a Comparative Tracking Index (CTI). The CTI value required to withstand flashover is typically indicated in part by the maximum voltage of the container sealing generator, but other parameters such as frequency also typically result in flashover.

  It has been found that instead of changing the contour of the insulator 111 and / or the conductive surface 116, a plastic insulator 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 can also be used either alone or in combination to reduce flashover, such as 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), nylon dispersed with polyphenylene oxide and acrylonitrile styrene acrylate .

  However, in some cases it is preferable to change the outer shape of the insulator 111 and / or the conductive surface 116 and / or use a plastic insulator that does not have a CTI value of about 300 to about 600 volts. obtain. Alternatively, specific coatings can be used either alone or in combination with one of the above manufacturing techniques to reduce flashover.

  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, it is expected that the electrode assembly 21 will be less susceptible to damage. This is because the electrode assembly 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. Alternatively, the entire electrosurgical instrument can be disposable, which again ensures a uniform, good quality seal with minimal flashover effects.

  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 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 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 electrosurgical energy applied to tissue 150, the user can cauterize, coagulate / dry and / or simply reduce or delay bleeding. Either.

  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 thus face in the same plane, but in some cases, electrodes 110 and 120 face each other at the distal end, resulting in It may be preferred that additional closing forces on the handles 16 and 18 are required to slightly deflect the electrodes in the same plane. This is expected to improve seal quality and 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's outer surface during sealing or after the end effector (or its components) and the surrounding tissue It is anticipated that a molded article can be provided.

  Alternatively, certain of the above-described coatings can be used either alone or in combination with one of the above manufacturing techniques to supplement the overall thermal diffusion reduction. These effects were filed at the same time as the present application and are pending, commonly assigned Application No. [203-2898] (which is the title of “ELECTROSURGICAL INSTRUMENT WHICH REDUCES COLLATETAL DAMAGING TO ADJACENT TISSUE”, by Johnson et al.) Are discussed in detail.

  Although only one embodiment of the present disclosure has been described, the present disclosure is as broad as the art allows, and the present specification should be construed to read as well, so the present disclosure is not limited thereto. Is not to be interpreted. 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.

10 Bipolar forceps
12, 14 shaft
16, 18 Handle member
20 Mechanical forceps
21 Electrode assembly
22, 24 End effector
41 socket
42, 44 Jaw member
111, 121 base material
126 Conductive seal surface

Claims (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 one another, 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 which comprises a conductive sealing surface and an insulating substrate, the electrodes being removably engaged with the end effector of the instrument such that they are in opposing relationship to each other. Possible electrodes,
Wherein 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.

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