JP2004524919A - Electrosurgical instruments to reduce heat spread - Google Patents

Abstract

An electrosurgical instrument comprising opposed end effectors and a handle for effecting movement of the end effectors relative to one another. The device includes a housing and a pair of electrodes. Each electrode preferably comprises a conductive surface (which can be dimensioned, for example, for sealing, clamping and / or cutting) and an insulating substrate, the insulating substrate comprising It is dimensioned to be engagable with the end effector so that it is in an opposing relationship. The dimensions of the insulating substrate are different from the dimensions of the conductive surface to reduce thermal spread 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.

Description

[Background Art]
[0001]
(Cross-reference of related applications)
This application is a pending application Ser. No. 09 / 387,883, filed Sep. 1, 1999, which is a continuation of U.S. Ser. No. 08 / 968,496, filed Nov. 12, 1997. , Which is hereby incorporated by reference in its entirety).
[0002]
(background)
The present disclosure relates to electrosurgical instruments used for open and endoscopic surgical procedures. More specifically, the present disclosure relates to bipolar forceps, which limit heat spread to adjacent tissue structures and / or reduce this heat spread and the rate of flashover during actuation With an electrode assembly designed to reduce
[0003]
(Technical field)
A hemostat or forceps is a simple pliers-like tool that uses mechanical movement between its jaws to clamp tissue and generally to grasp, dissect, and / or clamp tissue Used in open surgical procedures. Electrosurgical forceps utilize both mechanical clamping and electrical energy to heat tissue and blood vessels to provide hemostasis by coagulating, cauterizing, and / or sealing tissue.
[0004]
Using electrosurgical forceps, a surgeon can cauterize, coagulate / dry, and / or simply reduce bleeding 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.
[0005]
Monopolar forceps utilize one active electrode with a clamping end effector and a remote patient return electrode or pad externally attached to the patient. When electrosurgical energy is applied, it is transmitted from the active electrode to the surgical site and through the patient to the return electrode.
[0006]
Bipolar electrosurgical forceps utilize two generally opposing electrodes, which are generally disposed on an inward or opposing surface of an end effector, which in turn is coupled to an electrosurgical generator. Is electrically connected to Each electrode is charged to a different potential. Because tissue is a conductor of electrical energy, if the end effector is used to clamp, grasp, seal, and / or cut tissue therebetween, this electrical energy will pass through the tissue. Can be selectively transmitted.
[0007]
Over the past decades, the tradition of using endoscopes and endoscopic instruments, which access organs through small puncture-like incisions, to access vital vital organs and body cavities Surgeons are praising the natural opening method. The endoscopic instrument is inserted into the patient via a cannula or port, which is made with the trocar. Typical sizes of cannulas range from 3 millimeters to 12 millimeters. Usually, smaller cannulas are preferred, but as can be appreciated, this ultimately requires a design for the instrument manufacturer who must find a way to produce a compatible surgical instrument via the cannula. Here is the above challenge.
[0008]
Certain surgical procedures require that blood vessels or vascular tissue be sealed. However, due to spatial limitations, surgeons have difficulty suturing vessels or performing other traditional methods of controlling bleeding (eg, clamping and / or tying laterally dissected vessels). Can be Blood vessels, often in the range of less than 2 millimeters in diameter, can be closed using standard electrosurgical techniques. If larger vessels are cut, the surgeon may need to switch the endoscopic procedure to an open surgical procedure, thereby abandoning the benefits of laparoscopy.
[0009]
It is known that the process of coagulating small vessels differs in principle from vessel sealing. For the purposes herein, the term “clotting” is defined as the process by which tissue cells are ruptured to dry dry tissue. The term "vascular seal" is defined as the process of liquefying collagen in tissue so that the tissue crosslinks and reforms into a fused mass. Thus, while the coagulation of small vessels is sufficient to close them, larger vessels need to be sealed to ensure permanent closure.
[0010]
Several scholarly articles disclose methods of sealing small blood vessels using electrosurgery. A paper entitled Studies on Coagulation and the Development of an Automatic Computerized Bipolar Coagulator (J. Neurosurg., Vol. 75, July 1991) describes the use of a device to seal a small blood vessel. I have. The article states that arteries with diameters greater than 2-2.5 mm cannot be coagulated safely. The second paper is titled Automatically Controlled Bipolar Electrocoagulation— “COA-COMP” (Neurosurg. Rev. (1984), pp. 187-190), and electrosurgical the blood vessels so as to avoid scorching of the vessel walls. Describes how to transmit dynamic power.
[0011]
With particular reference to vascular sealing, two main mechanical parameters (the pressure applied to the blood vessel and the gap distance between the electrodes (both of which are Which affects the thickness of the blood vessels) must be precisely controlled. More specifically, accurate application of pressure is important for several reasons: 1) to oppose the walls of blood vessels; 2) to pass sufficient electrosurgical energy through the tissue. 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 instances, the fused vessel wall is optimally between 0.001 inches and 0.006 inches. Below this range, the seal may be torn or torn, and above this range, the lumen may not be sealed properly or effectively.
[0012]
Numerous bipolar electrosurgical instruments have been proposed in the past for various open and endoscopic surgical procedures. For example, U.S. Pat. Nos. 2,176,479 to Willis, U.S. Pat. Nos. 4,005,714 and 4,031,898 to Hiltebrandt, U.S. Pat. Nos. 5,827,274, and Boebel et al. U.S. Patent Nos. 5,290,287 and 5,312,433; U.S. Patent Nos. 4,370,980, 4,552,143 to Lottick, 5,552,143, 5,026,370 and 5, Nos. 116,332, 5,443,463 to Stern et al., 5,484,436 to Eggers et al. And 5,951,549 to Richardson et al. To an electrosurgical instrument for coagulating, sealing and / or cutting a tissue.
[0013]
It has been found that sealing, cutting and / or cauterizing tissue using electrosurgical instruments can result in some degree of so-called "thermal diffusion" across adjacent tissue structures. For the purposes herein, the term "thermal diffusion" generally refers to heat transfer (thermal conduction, thermal convection or current loss) moving along the periphery of a conductive surface. This may also be referred to as "collateral damage" to adjacent tissue. As can be appreciated, reducing the heat spread during the electrical procedure reduces the potential for unintended or undesired collateral damage to surrounding tissue structures adjacent to the intended treatment site. Lower.
[0014]
Instruments with a dielectric coating disposed along the outer surface are known and are used to prevent tissue "branching" at the normal point to the working site. In other words, these coatings are designed primarily to reduce accidental burning of tissue as a result of accidental contact with the external end effector. To the extent known, these coatings are not designed to reduce collateral tissue damage or heat spread to adjacent tissue (tissue lying along the tissue plane) and they are not intended .
[0015]
It has also been found that cleaning and sterilizing many prior art bipolar instruments is often impractical, as the electrodes and / or insulators can be damaged. More specifically, electrically insulative materials (eg, plastics) are created by repeated sterilization cycles, which can ultimately result in instrument reliability and cause so-called "flashover" It is known that it can be damaged or damaged. As used herein, flashover is a result of inconsistent current tracking and / or activation irregularities on the surface of the insulator or insulating coating that can occur if the instrument is used repeatedly during surgery. Related to visible anomalies that occur as Briefly, flashover tends to char the surface of the insulator and can affect the life of the instrument and / or the electrode assembly. The effects and industry standards regarding flashover are described in Annual Book of ASTM Standards, Vol. 10.02, symbol: D495-84; D618; D2303 and D3638.
[0016]
Several electrosurgical instruments have been introduced that are known to solve many of the above problems associated with sealing, cutting, cauterizing and / or coagulating vessels of different sizes. Some of these devices are described in co-pending U.S. patent application Ser. No. 09 / 178,027, filed Oct. 23, 1998, entitled OPEN VESSEL SEALING FORCEPS WITH DISPOSABLE ELECTROREDES; co-pending U.S. Pat. U.S. Patent Application Serial No. 09 / 425,696, entitled OPEN VESSEL SEALING FORCEPS WITH DISPOSABLE ELECTROCODES; co-pending U.S. Patent Application No. Co-pending U.S. Patent Application Serial No. 09 / 621,029, filed July 21, 2016, entitled ENDOSCOPIC B IPOLLAR ELECTROSURGICAL FORCEPS, the entire contents of which are all incorporated herein by reference.
[0017]
Accordingly, there is a need to develop electrosurgical instruments, including instruments that can effectively reduce the undesirable effects of heat diffusion across tissue structures and effectively reduce the incidence of flashover.
DISCLOSURE OF THE INVENTION
[Means for Solving the Problems]
[0018]
(Abstract)
The present disclosure relates generally to open and / or endoscopic electrosurgical instruments, which include electrodes, which are separated from the remainder of the instrument by a uniquely designed insulating substrate and conductive surface. Electrically and thermally separated electrodes. It is envisioned that the geometry of this insulating substrate relative to the geometry of the conductive surface will contribute to the overall reduction of 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.
[0019]
More particularly, the present disclosure relates to an electrosurgical instrument, which includes an opposing end effector and a handle for moving the end effector relative to each other. The device 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 comprising an end effector and The electrodes are dimensioned to be selectively engagable, such that the electrodes are in opposing relation to each other. The dimensions of the insulative substrate differ from the dimensions of the conductive surface to reduce thermal spread to adjacent tissue structures. The insulating substrate is made of a material having a comparative tracking index of about 300 volts to about 600 volts to reduce the incidence of flashover.
[0020]
Preferably, the dimensions of the insulating substrate are different from the dimensions of the conductive surface, which may not only reduce heat spread to adjacent tissue structures, but may also contribute to reducing the incidence of flashover.
[0021]
In other embodiments, the insulating substrate is provided with a conductive surface by stamping, by overmolding, by overmolding the stamped plate, and / or by overmolding the metal injection molded plate. Attached to. All of these manufacturing techniques produce electrodes having a conductive surface substantially surrounded by an insulating substrate. These uniquely described embodiments described herein are intended to effectively reduce heat spread to adjacent tissue structures during and / or immediately after activation. In addition, certain cross-sectional biases may also contribute to reducing the incidence of flashover. The conductive surface may also include a pinch trim, which facilitates the fixed engagement of the conductive surface with the insulating substrate and also simplifies the overall manufacturing process.
[0022]
In another embodiment, the conductive surface comprises a peripheral edge, the peripheral edge has a radius, and the insulator contacts the conductive surface along an adjacent edge, the adjacent edge comprising: Generally, it is tangential to the radius and / or contacts along the radius. Preferably, at the interface, the conductive surface is raised relative to the insulator.
[0023]
The insulating substrate may be made from a plastic or plastic-based material having a comparative tracking index from 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), polyether sulfone (PES), aliphatic polyketone, acetal ( POM) copolymers, polyurethanes (PU and TPU), nylon with polyphenylene oxide dispersed, 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 to spread heat to adjacent tissue structures Can contribute to the overall reduction of
[0024]
In another embodiment of the present disclosure, the insulating substrate of each electrode includes at least one mechanical interface such that it engages 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 mechanical interface of the corresponding end effector may comprise a complementary socket, such as to accommodate the detent.
[0025]
Another embodiment of the present disclosure comprises a housing having a bifurcated distal end forming two resilient and flexible prongs, 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) with respect to the distal end of the shaft of the electrosurgical instrument. Preferably, this angle is between about 60 ° and about 70 °. The end effector, and then the electrode, may also be dimensioned to have a taper along the width "W" (see FIG. 2).
[0026]
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 engagable with a corresponding end effector and includes a 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 heat diffusion to adjacent tissue structures. , Can contribute to a reduction in the rate of flashover.
[0027]
In one embodiment, the electrode assembly engaging the device is removable, disposable and replaceable after being used beyond its intended number of activation cycles. Alternatively, the electrode assembly and / or the electrode may be integrally coupled with the end effector of the instrument and are not removable. In this example, the electrosurgical instrument (open or endoscope) can be designed for a single use application, and after the surgical procedure is completed, the entire instrument is completely disposable.
[0028]
(Detailed description)
By changing the configuration of the electrode insulating material relative to the conductive surface, the surgeon can more easily, more easily, and more efficiently reduce heat spread across or to adjacent tissue. And / or reduce the incidence of flashover. For the purposes herein, the term “thermal diffusion” generally refers to the transfer of heat (heat transfer, heat transfer) dissipated to adjacent tissue along the periphery of a conductive or electrically active surface. Convection or current dissipation). This may also be referred to as "collateral damage" to adjacent tissue. The term "flashover" simply refers to visible visible light 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 instrument life.
[0029]
The configuration of the insulating material surrounding the conductive surface can effectively reduce current dissipation and heat dissipation to adjacent tissue areas, and generally limit current transfer to the area between opposing electrodes. ,is assumed. As noted above, this differs from dielectrically coating the outer surface of the device at a point perpendicular to the designated site to prevent tissue "branching". These coatings are neither designed nor intended to reduce collateral tissue damage or thermal spread to adjacent tissue (tissue lying along the tissue activation plane). Not even.
[0030]
More specifically, altering the geometric dimensions of the insulator relative to the conductive surface is intended to alter the electrical path, thereby affecting heat spread / consequent damage to adjacent tissue structures. You. Preferably, the shape of the insulating substrate also separates the two electrically opposite polarities (ie, the electrodes) from each other, so that the tissue or tissue fluid forms an unintended bridge or path for current transfer. Reduce the likelihood of gaining. In other words, as described in more detail below, the insulator and the conductive surface are preferably dimensioned such that current is concentrated between opposing conductive surfaces.
[0031]
One way to reduce the incidence of flashover is to change the shape of the insulator with respect to the conductive surface, which effectively increases the total distance the current has to travel along a given electrical path. Is intended. It is also envisioned that manufacturing the insulating substrate from certain materials having certain properties will also reduce the incidence of flashover during operation.
[0032]
Referring now to FIGS. 1-3, a bipolar forceps 10 for use in conjunction with an open surgical procedure is shown by way of example, comprising a mechanical forceps 20 and an electrode assembly 21. In the drawings and the description that follows, the term “proximal” conventionally means the end of the forceps 10 that is closer to the user, while the term “distal” refers to the end farther from the user. Means Further, while most of the figures (ie, FIGS. 1-7A and 8A) show one embodiment of the instrument described in the present invention (eg, forceps 20) for use with open surgical procedures, The same properties as shown and described herein may also be used with or in combination with the endoscopic instrument 100, such as the embodiment illustrated by the example of FIG. 8B.
[0033]
1 to 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 has 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 handle members 16 and 18 attached thereto, which allow a user to attach at least one of the shaft portions (eg, 12) to the other (eg, 12). For example, it can be moved with respect to 14). Extending from the distal ends 17 and 19 of each shaft portion 12 and 14 are end effectors 24 and 22, respectively. End effectors 22 and 24 are movable relative to each other in response to movement of handle members 16 and 18.
[0034]
Preferably, the shaft portions 12 and 14 are fixed to each other at a point about the pivot 25 and proximal to the end effectors 24 and 22 so that movement of one of the handles 16, 18 is moved from the open position to the end position. The effectors 24 and 22 are relatively moved. Here, the end effectors 22 and 24 are disposed in a spatial relationship with respect 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. Assemble for gripping (see FIGS. 8A and 8B). It is envisioned that the pivot 25 has a large surface area to reduce torsion and movement of the forceps 10 during actuation. The forceps 10 can also be designed such that movement of one or both of the handles 16 and 18 moves one (eg, 24) of the end effectors relative to the other end effector (eg, 22). ,is assumed.
[0035]
3, the end effector 24 includes an upper or first jaw member 44 having an inwardly facing surface 45 and a plurality of mechanical interfaces disposed thereon. Interface is dimensioned 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 inwardly facing surface 45 of the jaw member 44 and is mounted on the upper electrode 120 of the disposable electrode assembly 21. It is dimensioned 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 is a disposable electrode assembly. 21 is contemplated.
[0036]
In some cases, fabricating the mechanical interface 41 along another face of the jaw member 44 and engaging the complementary mechanical interface of the electrode assembly 21 in a different manner (eg, from that face) 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, the opening 67 being provided on a complementary guide pin 124 disposed on an electrode 120 of the electrode assembly 21. Sized to accept
[0037]
The end effector 22 includes a second or lower jaw member 42 having an inwardly facing surface 47 opposite the inwardly facing surface 45. Preferably, the jaw members 42 and 44 are dimensioned substantially symmetrically, but in some cases it is preferable to manufacture two asymmetric jaw members 42 and 44, depending on the particular purpose. possible. In exactly the same manner as described above for 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 connected to the electrodes 110 of the electrode assembly 21. It is dimensioned to removably engage the complementary portion 112 disposed thereon. Similarly, jaw member 42 also includes an opening 65 disposed at least partially through inwardly facing surface 47, which includes a complementary guide pin 127 () disposed on electrode 110 of disposable electrode assembly 21. (See FIG. 4).
[0038]
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 envisioned that angling the end effectors 22, 24 with respect to the distal ends 19, 17 at an angle α is advantageous for two reasons: 1) Due to the angles of the end effectors, jaw members and electrodes, Apply a greater constant pressure for cutting and / or apply a more parallel and uniform tissue thickness for sealing purposes, and 2) a thicker proximal portion of the electrode, e.g. As a result of the taper along width "W"), it does not buckle due to the reaction force of tissue 150. The tapered “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 ° may be useful for certain anatomical structures involved in prostatectomy and cystectomy, such as the dorsal vein complex and the transverse pedicle ( Lateral pedicle)) is preferred for evaluation and activation.
[0039]
Preferably, shaft members 12 and 14 of mechanical forceps 20 apply a particular desired force to opposing inwardly facing surfaces of jaw members 22 and 24, respectively, when clamped or during sealing and / or cutting. Designed to communicate. In particular, because the shaft members 12 and 14 effectively work together in a spring-like manner (i.e., a bend that acts like a spring), the length, width, height and deflection of the shaft members 12 and 14 are opposite. Directly affects the total transmission force applied to the jaw members 42 and 44 that are to be moved. Preferably, jaw members 22 and 24 are more rigid than shaft members 12 and 14, and the strain energy stored in shaft members 12 and 14 provides a constant closing force between jaw members 42 and 44. provide.
[0040]
Each shaft member 12 and 14 also includes ratchet portions 32 and 34, respectively. Preferably, each ratchet (eg, 32) extends in a substantially vertically aligned manner from the proximal end 13 of its respective shaft member 12 toward the other ratchet 34, such that each ratchet 32 and 34 Face 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, which 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 location. . In the embodiment shown in FIG. 1, ratchets 32 and 34 interlock at several different locations. Preferably, each ratchet position holds a particular (ie, constant) strain energy within shaft members 12 and 14, which in turn applies a particular force to end effectors 22 and 24, and thus electrodes 120 and 110. introduce. This is particularly relevant during sealing.
[0041]
In some cases, it may be preferable to provide other mechanisms to control and / or limit movement of jaw members 42 and 44 relative to each other. For example, a ratchet and pawl system can be used to coordinate the movement of the two handles to separate units, which in turn move the jaw members 42 and 44 separately with respect to each other.
[0042]
Preferably, at least one (e.g., 14) of the shaft members includes a protrusion 99, which facilitates manipulation of the forceps 20 during a surgical condition and, as described in more detail below, a machine. Mounting of the electrode assembly 21 on the mechanical forceps 20 is facilitated.
[0043]
As best shown in FIGS. 2, 3 and 5, one embodiment of the electrosurgical instrument includes an electrode assembly 21 which is adapted to operate in combination with 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 located near the proximal end 77 of the housing 71 and is dimensioned to removably engage and / or surround the handle 18 of the mechanical forceps 20. Similarly, shaft 78 is sized to surround and / or releasably engage pivoting plate 74 located near shaft 14 and distal end 76 of housing 71, and pivoting mechanical forceps 20 It is dimensioned to surround the point 25 and at least a portion of the 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 the respective component parts 12, 16 or 14,18 thereof.
[0044]
In the embodiment shown in FIG. 3, the handle 18, shaft 14, pivot point 25 and a portion of the distal end 19 are all sized to fit within corresponding channels located 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 point 25 and a portion of distal end 19. Such dimensions.
[0045]
The electrode assembly 21 also comprises a cover plate 80, which is also designed to surround and / or engage the mechanical forceps 20 in a manner similar to that described for 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 located near the proximal end 85 and is preferably dimensioned to removably engage and / or surround the handle 18 of the mechanical forceps 20. Similarly, shaft plate 88 is sized to surround and / or releasably engage shaft 14, and pivot plate 94 disposed near distal end 86 provides a pivot point for mechanical forceps 20. Designed to surround 25 and distal end 19. Preferably, handle 18, shaft 14, pivot point 25 and distal end 19 are all corresponding channels (not shown) located within cover plate 80 in a manner similar to that described above with respect to housing 71. Dimensions that fit inside.
[0046]
As best shown with respect to FIGS. 3 and 4, the housing 71 and the cover plate 80 are dimensioned to engage one another over the first member (eg, 11) of the mechanical forceps 20, so that , The first member 11 and its respective component parts (eg, handle 18, shaft 14, distal end 19 and pivot point 25) are disposed therebetween. Preferably, the housing 71 and the cover plate 80 include a plurality of mechanical interfaces located at various locations along the interior of the housing 71 and the cover plate 80 to provide mechanical engagement with one another. 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 a corresponding plurality of detents (not shown). Are dimensioned to releasably engage. Either a male mechanical interface or a female mechanical interface or a combination of mechanical interfaces can be located in the housing 71 with a mating mechanical interface located on or in the cover plate 80. Is assumed.
[0047]
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 that extend outwardly from its distal end 76 to form electrodes 110 and 120. Is bifurcated to support each. More specifically, electrode 120 is attached to end 90 of prong 105 and electrode 110 is attached to end 91 of prong 103. Electrodes 110 and 120 may be applied to ends 91 and 90 in any known manner (eg, friction fit, slide fit, snap fit engagement, crimp, etc.). It is further contemplated that electrodes 110 and 120 may be selectively removable from ends 90 and 91 depending on the particular purpose and / or to facilitate assembly of electrode assembly 21. . As noted above, the inventive concepts disclosed herein also do not comprise a selectively removable electrode assembly, but rather have an integrally associated electrode disposed thereon. It may relate to an electrosurgical instrument comprising an end effector.
[0048]
A pair of wires 60 and 62 are connected to electrodes 120 and 110, respectively, as best shown in FIGS. Preferably, wires 60 and 62 are bundled together and form a wire bundle 28 (FIG. 4), which is proximal to housing 71 from terminal connector 30 (see FIG. 3). To the end 77, along the interior of the housing 71, to the distal end 76. Wire bundle 28 splits 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 or wire bundles 28 are captured at various pinch points along the inner cavity of electrode assembly 21 and wires 60 and 62 within electrode assembly 21 by attaching cover plate 80. May be preferred.
[0049]
This arrangement of wires 60 and 62 is designed to be convenient for the user so that it does not substantially interfere with the operation of bipolar forceps 10. As mentioned above, the proximal end of wire bundle 28 is connected to terminal connector 30, but in some cases, it is preferable to extend wires 60 and 62 to an electrosurgical generator (not shown). possible.
[0050]
As best shown in FIG. 6, the electrode 120 includes a conductive surface 126 and an electrically insulating substrate 121, which may be snap-fit engagements or some other assembly method (eg, a slide-fit). , 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 located within the jaw member 44 of the end effector 24 (see FIG. 2). See). This substrate 121 not only insulates the current, but also aligns the electrodes 120, both of which contribute to 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 has the electrode 120 compared to the conventional manufacturing technique (resulting in a height of “h1”) (FIG. 7B). Reduce the overall height “h2” (FIG. 7C). The lower height "h2" allows the user to access smaller areas within the body and facilitates actuation around more sensitive tissue areas.
[0051]
Further, it is contemplated that the overmolding technique provides greater insulation along the sides of the conductive surface, which also reduces heat diffusion, due to the electrodes having less contact with the tissue. In this way (ie, the conductive surface area is reduced), by matching the dimensions of the substrate (eg, 121) and the electrode 120, the intended area (which may contact the outer edge of the electrode 120) It is assumed that the current is limited (i.e., concentrated) to the intended area, rather than flowing through the tissue outside the (see FIG. 7B). Providing greater insulation along the sides of the conductive surface may also effectively reduce the incidence of flashover.
[0052]
Preferably, the substrate 121 includes a plurality of bifurcated detents 122 that are configured to compress during insertion into the socket 41 and expand and removably engage the socket 41 after insertion. It is envisioned that the snap fit engagement of electrode 120 and jaw member 44 will accommodate a wide range of manufacturing tolerances. Substrate 121 also includes alignment pins or guide pins 124. This pin 124 is dimensioned to engage the opening 67 in the jaw member 44. Slide fit technology is also described with reference to commonly assigned co-pending U.S. Patent Application No. 203-2348 CIP2PCT (Tetzlaff et al.), The entire contents of which are incorporated herein by reference. Such slide fit techniques are contemplated.
[0053]
The conductive surface 126 engages the distal end 90 of the prong 105 of the electrode assembly 21 and electrically engages a corresponding wire connector attached to a wire 60 located within the electrode assembly 21. It has a designed wire crimp 145. 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 conductive surface 126 (116) may be dimensioned as a sealing surface, a clamping surface, and / or a shearing or cutting surface, depending on the particular purpose.
[0054]
Electrode 110 includes similar elements and materials for insulating and conducting electrosurgical current to tissue 150. More specifically, electrode 110 comprises a conductive surface 116 and an electrically insulating substrate 111. The surface and the substrate are attached to one another by one of the above assembly methods. The substrate 111 includes a corresponding plurality of sockets 43 located on the jaw member 42 and a plurality of detents 112 sized to engage the openings 65. 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 on the housing 71. . The conductive surface 116 also includes an opposing surface 115 that carries 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 include similar components and / or dimensions for insulating and conducting electrical energy in a manner that effectively reduces the rate of thermal diffusion and flashover. . The stray current may be further limited by casting the forceps and / or manufacturing the forceps using a non-conductive material and / or coating the edges of electrodes 110 and 120 with an insulating coating.
[0055]
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 heat spreading, it is envisioned that fabricating electrodes 110 and 120 in this manner would reduce heat spreading and stray currents that can flow through 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. It reduces the likelihood that the stray current will flow over the path. For flashover, changing the shape of the insulator 111 and / or the conductive surface creates a longer path for current flowing over the insulator 111 before the flashover occurs.
[0056]
For example, as best shown in a comparison of FIG. 7B (prior art) with newly disclosed FIGS. 7C, 7D, 14A and 14B, the substrates 111, 121 may extend along a width “W”. (FIG. 2), so that the width of the insulating substrate (eg, 111) is greater than the width of the conductive surface (eg, 116). It is envisioned that these configurations of conductive surface 116 and insulator 111 can be achieved by various manufacturing techniques (eg, stamping and / or metal injection molding overmolding). It is defined herein that stamping includes virtually any pressure operation known in the art. 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 a similar configuration of conductive surface 116 and insulator 111 that effectively reduces thermal spread to adjacent tissue.
[0057]
As best seen in FIG. 7D, electrode 116 may also include a pinch trim 131 that facilitates the secure, integral engagement of insulator 111 and 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 conductive surfaces 116, 126 and the outer periphery of the substrates 111, 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 surrounding tissue. One or more barriers 161 may be attached to end effectors 22, 24 and / or insulating substrates 111, 121, depending on the particular purpose to achieve a particular result.
[0058]
14A, 14B, 14C and 15 show the raised conductive surfaces 116, 126 compared 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 surrounding tissue structures. It is envisioned that the insulators 111, 121 and the conductive surfaces 116, 126 may be dimensioned to contact at or substantially along the border or joined longitudinally oriented edges 129, 139. You. These edges are rounded to reduce current density 141 and current dissipation near interfaces 129, 139 and opposing conductive surfaces 116, 126.
[0059]
For example and by way of example, FIGS. 12 and 13A-13C show configurations of other electrodes 110, 120 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 emanating from the counter conductive surfaces 116, 126 (where the current is Is known to flow perpendicular to these electric field lines). As can be seen, the electric field 135 occurs well beyond the intended treatment site, which may contribute to increased lateral tissue damage and possible amputation.
[0060]
As shown in FIGS. 13A-13C, by providing insulators 111, 121 in contact with conductive surfaces 116, 126, electric field distribution 135 can be significantly 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 may also have a negative effect, possibly causing a cut in the tissue or a penetration of the tissue into the electrode or conductive surface at this site.
[0061]
14A-15 illustrate configurations of various electrodes 110, 120 in accordance with the present disclosure, wherein conductive surfaces 116, 126 and insulators 111, 121 provide a current density 141 between opposing electrodes 110, 120. Designed to reduce volume. More specifically, FIGS. 14A and 14B show a raised pair of conductive surfaces 116, 126 (relative to insulators 111, 121), which have radii "r" and "r '" respectively. The outer circumferences 145 and 147 are provided. Preferably, insulators 111, 121 face outer perimeters 145, 147 and form adjacent edges or interfaces 129, 139 along radii "r" and "r '", respectively. It is contemplated that configuring the electrodes 110, 120 in this manner will effectively reduce the current density 141 between the perimeters 145, 147 of the opposing conductive surfaces 116, 126. 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 is provided. A distribution 135 is further provided. Returning to FIG. 7C, it is anticipated that insulator 111 may also face outer periphery 145 in a substantially tangent manner around radius “r”. Again, this profile also tends to reduce current density and thermal spread, and may also contribute to reducing the occurrence of flashover.
[0062]
FIG. 15 also faces at a 90 ° angle, but with insulators 111, 121 and insulators 111, 121 and conductive surface 116 located far from the radiused edge 145 of conductive surfaces 116, 126. , 126 are shown. If the exposure of the edge 145 is too large, 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. It is expected that it can be zero.
[0063]
Preferably, the radii "r" and "r '" of the outer perimeters 145, 147 of the conductive surface are approximately the same and are between about 10/1000 inches and about 30/1000 inches. However, it is contemplated that each radius "r" and "r '" may be differently sized depending on the particular purpose or to achieve the desired result.
[0064]
While geometric modification of the insulator 111 to the conductive sealing surface 116 is contemplated to reduce the occurrence of flashover and heat spread, in some cases, to reduce flashover and heat spread, It may be preferable to simply utilize different materials for the insulator. For example, and particularly with respect to flashover, all plastics are known to have different resistance to flashover, which is typically measured using the Comparative Tracking Index (CTI). You. 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 , Causing a flashover.
[0065]
It has been found that instead of or in addition to changing the geometry of the insulator 111 and / or the conductive surface 116, a 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), polyamide (Polymide), 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), either alone or in combination, can also be utilized to reduce flashover.
[0066]
However, in some cases, changing the geometry of both the insulator 111 and / or the conductive surface 116 and / or utilizing plastic insulation that does not have a CIT value of about 300 to about 600 volts. May be preferred. Alternatively, certain coatings can be utilized, either alone or in combination with one of the above manufacturing techniques, to reduce flashover and heat spread.
[0067]
FIG. 8A illustrates one embodiment of the present disclosure, which shows the bipolar forceps 10 in use, where the handle members 16 and 18 have been moved closer together to apply a clamping force to the tubular tissue 150. Applied, resulting in a seal 152, as shown in FIGS. Once sealed, the tubular vessel 150 may be cut along the seal 152 to separate the tissues 150 and form a gap 154 therebetween, as shown in FIG. Alternatively, 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.
[0068]
After the bipolar forceps 10 have been used, or if the electrode assembly 21 is damaged, the electrode assembly 21 can be easily removed and / or replaced, and a new electrode assembly 21 can be installed in the same manner as described above. Can be attached to the forceps. By making the electrode assembly 21 disposable, it is expected that the electrode assembly 21 will be less likely to be damaged. This is because the 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 (e.g., conductive surfaces 126, 116 and insulating surfaces 121, 111) ensure a certain reduction in heat spread across the tissue and / or the occurrence of flashover Decrease rate. Alternatively, the entire electrosurgical instrument may be disposable, which may again contribute to a reduction in heat spread across the tissue and / or reduce the incidence of flashover.
[0069]
FIG. 8B shows the endoscope bipolar instrument 100 in use, where movement of the handle assembly 128 exerts a clamping force on the tubular tissue 150 to provide a seal 152 as shown in FIGS. Is generated. 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 the opposing jaw members of electrode assembly 122. You. More specifically, the movable handle 118b is progressively moved toward the fixed handle 118a, which in turn causes the relative movement of the jaw members from the spaced open position to the closed operating position. The rotation member 123 allows a user to rotate the electrode assembly 122 to a position around the tubular tissue 150 before actuation. Again, 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.
[0070]
After the jaw members close around tissue 150, the user then applies electrosurgical energy to tissue 150 via connection 128. By controlling the intensity, frequency and duration of the electrosurgical energy applied to the tissue 150, the user can minimize the amount of incidental or thermal damage to surrounding tissue and minimize the incidence of flashover. It is possible to cauterize, coagulate / dry, seal, cut, and / or simply reduce or delay bleeding.
[0071]
From the foregoing and with reference to the various figures, those skilled in the art will appreciate that certain modifications may also be made to the present disclosure without departing from the scope thereof. For example, it is preferred that the electrodes 110 and 120 face in parallel opposition, and thus face in the same plane, but in some cases the electrodes 110 and 120 may be slightly facing each other at the distal ends. It may be preferred that an additional closing force on handles 16 and 18 is required to bias and consequently deflect the electrodes in the same plane.
[0072]
Nickel-based material, coating, stamping, metal injection molding, the outer surface of the end effector designed to reduce contact between the end effector (or its components) and surrounding tissue during operation It is envisioned that can be provided.
[0073]
Although only one embodiment of the present disclosure is described, it is intended that the present disclosure be as broad as the art will allow and that this specification be read as well. Is not to be construed as limiting. Therefore, the above 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 appended claims.
[Brief description of the drawings]
[0074]
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, with parts separated.
FIG. 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, with parts separated.
FIG. 7A is a perspective view of the lower electrode of the electrode assembly of FIG. 5, wherein 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 extending beyond the sides of a radiused electrode.
FIG. 7D is a cross-section of an overmolded stamp electrode configuration showing the insulator capturing the pinch trim hanging from the conductive surface.
FIG. 7E is a cross section of an electrode configuration, showing a pliable barrier to control / regulate the heat dissipated from a conductive surface located around the perimeter of the opposing electrode and insulator.
FIG. 8A is a perspective view of an open forceps of the present disclosure, illustrating operative movement of an electrosurgical instrument around a tubular vessel.
FIG. 8B is a perspective view of an endoscope version of the present disclosure, illustrating operative movement of the instrument.
FIG. 9 is an enlarged partial perspective view of a sealing portion of a tubular blood vessel.
FIG. 10 is a longitudinal section of the sealing site taken along line 10-10 of FIG. 9;
FIG. 11 is a longitudinal section of the sealing site of FIG. 9 after separation of the tubular vessel.
FIG. 12 is a contour plot showing the dissipation of electrosurgical current across tissue using electrodes without insulators.
FIG. 13A is a contour plot showing the dissipation of electrosurgical current across tissue using an electrode with 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 an adjacent edge or interface between an insulator and a conductive surface.
FIG. 13C is a magnified plot of the electric field magnitude of the electrode configuration of FIG. 13A showing the distribution of the electrosurgical electric field distribution at adjacent edges or at the interface between the insulator and the conductive surface. Shows current density and relative 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. It is.
FIG. 14B is an expanded isotherm plot of FIG. 14A showing the current density and relative dissipation of an electrosurgical current at an adjacent edge or interface between an insulator and a conductive surface. .
FIG. 14C is a magnified plot of the electric field magnitude of the electrode configuration of FIG. 14A, showing the current of an electrosurgical electric field distribution at an adjacent edge or interface between an insulator and a conductive surface. Shows density and relative dissipation.
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 the insulation. It is.

Claims (10)

An electrosurgical instrument having an opposing end effector and a handle for effecting movement of the end effector relative to one another, the electrosurgical instrument comprising:
A housing; and a pair of electrodes, each of the electrodes comprising a conductive surface and an insulating substrate, the dimensions of the insulating substrate to reduce heat diffusion to adjacent tissue structures. A pair of electrodes, different from the surface dimensions, and wherein the insulating substrate is made of a material having a comparative tracking index of about 300 volts to about 600 volts to reduce the incidence of flashover;
An electrosurgical instrument comprising: The electrosurgical instrument according to claim 1, wherein the insulating substrate is made from a material having a comparative tracking index of about 300 volts to about 600 volts. The insulating substrate is nylon, syndiotactic polystyrene, polybutylene terephthalate, polycarbonate, acrylonitrile butadiene styrene, polyphthalamide, polyimide, polyethylene terephthalate, polyamide-imide, acrylic, polystyrene, polyether sulfone, aliphatic polyketone, acetal copolymer The electrosurgical instrument according to claim 1, wherein the electrosurgical instrument is selected from the group consisting of: polyurethane, nylon, polyphenylene oxide dispersed nylon, and acrylonitrile styrene acrylate. The electrosurgical instrument according to claim 1, wherein the insulating substrate is attached to the conductive surface by overmolding a stamped plate. The electrosurgical instrument according to claim 1, wherein the insulating substrate is attached to the conductive surface by overmolding a metal injection molded plate. The electrosurgical instrument according to claim 1, wherein the conductive surface of at least one electrode comprises a pinch trim, and wherein the insulating substrate extends beyond a periphery of the conductive surface. The electric of claim 1, wherein the insulating substrate of each of the electrodes comprises at least one mechanical interface for engaging a complementary mechanical interface located on a corresponding end effector of the instrument. Surgical instruments. The electrosurgical instrument according to claim 1, wherein the conductive surfaces of the opposing jaw members cooperate to seal tissue. The electrosurgical instrument according to claim 1, wherein the conductive surface of the opposing jaw member comprises a shear surface cooperating to cut tissue. An electrosurgical instrument having a handle and at least one shaft for causing movement of a pair of opposing end effectors relative to each other, the electrosurgical instrument comprising: ,Less than:
housing;
A pair of electrodes, each having a conductive surface having a first geometric shape and an insulating substrate having a second geometric shape, wherein the electrodes are such that the electrodes are An electrode integrally coupled to the end effector of the device so as to be in an opposing relationship;
With
Here, 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 electrosurgical instrument, 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.