Patent Application
20060064086
The present disclosure relates to forceps used for open and/or endoscopic surgical procedures. More particularly, the present disclosure relates to a forceps which applies a unique combination of mechanical clamping pressure and electrosurgical current to micro-seal soft tissue to promote tissue healing.
A hemostat or forceps is a simple plier-like tool which uses mechanical action between its jaws to constrict vessels and is commonly used in open surgical procedures to grasp, dissect and/or clamp tissue. Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize and/or seal tissue. The electrode of each opposing jaw member is charged to a different electric potential such that when the jaw members grasp tissue, electrical energy can be selectively transferred through the tissue. A surgeon can either cauterize, coagulate/desiccate and/or simply reduce or slow bleeding, by controlling the intensity, frequency and duration of the electrosurgical energy applied between the electrodes and through the tissue.
For the purposes herein, the term “cauterization” is defined as the use of heat to destroy tissue (also called “diathermy” or “electrodiathermy”). The term “coagulation” is defined as a process of desiccating tissue wherein the tissue cells are ruptured and dried. “Vessel sealing” is defined as the process of liquefying the collagen, elastin and ground substances in the tissue so that it reforms into a fused mass with significantly-reduced demarcation between the opposing tissue structures (opposing walls of the lumen). Coagulation of small vessels is usually sufficient to permanently close them. Larger vessels or tissue need to be sealed to assure permanent closure.
Commonly-owned U.S. application Ser. Nos. PCT application Ser. No. PCT/US01/11340 filed on Apr. 6, 2001 by Dycus, et al. entitled “VESSEL SEALER AND DIVIDER”, U.S. application Ser. No. 10/116,824 filed on Apr. 5, 2002 by Tetzlaff et al. entitled “VESSEL SEALING INSTRUMENT” and PCT application Ser. No. PCT/US01/11420 filed on Apr. 6, 2001 by Tetzlaff et al. entitled “VESSEL SEALING INSTRUMENT” teach that to effectively seal tissue or vessels, especially large vessels, two predominant mechanical parameters must be accurately controlled: 1) the pressure applied to the vessel; and 2) the gap distance between the conductive tissue contacting surfaces (electrodes). As can be appreciated, both of these parameters are affected by the thickness of the vessel or tissue being sealed. Accurate application of pressure is important for several reasons: to oppose the walls of the vessel; to reduce the tissue impedance to a low enough value that allows enough electrosurgical energy through the tissue; to overcome the forces of expansion during tissue heating; and to contribute to the end tissue thickness which is an indication of a good seal. It has been determined that a typical sealed vessel wall is optimum between 0.001 inches and 0.006 inches. Below this range, the seal may shred or tear and above this range the lumens may not be properly or effectively sealed.
With respect to smaller vessels, the pressure applied become less relevant and the gap distance between the electrically conductive surfaces becomes more significant for effective sealing. In other words, the chances of the two electrically conductive surfaces touching during activation increases as the tissue thickness and the vessels become smaller.
As can be appreciated, when cauterizing, coagulating or sealing vessels, the tissue disposed between the two opposing jaw members is essentially destroyed (e.g., heated, ruptured and/or dried with cauterization and coagulation and fused into a single mass with vessel sealing). Other known electrosurgical instruments include blade members or shearing members which simply cut tissue in a mechanical and/or electromechanical manner and, as such, also destroy tissue viability.
When trying to electrosurgically treat large, soft tissues (e.g., lung, intestine, lymph ducts, etc.) to promote healing, the above-identified surgical treatments are generally impractical due to the fact that in each instance the tissue or a significant portion thereof is essentially destroyed to create the desired surgical effect, cauterization, coagulation and/or sealing. As a result thereof, the tissue is no longer viable across the treatment site, i.e., there remains no feasible path across the tissue for vascularization.
Thus, a need exists to develop an electrosurgical forceps which effectively treats tissue while maintaining tissue viability across the treatment area to promote tissue healing.
A need exists also to enhance sealing strength in tissue fusion by increasing resistance to fluid flow or increased pressure at the fusion site so as to minimize entry of fluid into the perimeter of the fused site during burst strength testing. The entry of fluid often results in seal failure due to propagation of the fluid to the center of the tissue seal.
In addition, a need exists lengthen the jaws of existing electrosurgical forceps beyond current mechanical limits so as to increase current density to reduce sealing time, and increase tissue desiccation and seal strength.
It is an object of the present disclosure to provide a bipolar electrosurgical forceps having jaw members which are configured with electrode surfaces with a plurality of flow paths so as to increase resistance to fluid flow through the tissue seal zone, or increasing pressure states at the fusion site, thereby increasing tissue seal integrity.
It is an object of the present disclosure to reduce mechanical tolerance requirements of a bipolar electrosurgical forceps while maintaining or increasing current density by providing jaw members which are longer than those of the prior art.
It is an object of the present disclosure to provide a bipolar electrosurgical forceps having a plurality of electrodes on each jaw member to form an array of individual pairs of corresponding or counterpart electrodes on each jaw member so that the activation sequence and electrosurgical energy applied to each individual pair of corresponding or counterpart electrodes may be varied to maintain or increase pressure of the tissue during tissue desiccation, thereby increasing tissue seal integrity.
The present disclosure relates to a bipolar electrosurgical forceps, which includes first and second opposing jaw members having respective inwardly facing surfaces associated therewith. The first and second jaw members are adapted for relative movement between an open position to receive tissue and a closed position engaging tissue between the inwardly facing surfaces. The first and second jaw members each include a plurality of electrodes on the inwardly facing surfaces thereof. The plurality of electrodes of the first jaw member are disposed in substantially vertical registration with the plurality of electrodes of the second jaw member, and each of the plurality of electrodes is configured to connect to a source of electrosurgical energy.
In one embodiment, electrodes on at least one jaw member may be grouped in pairs and each respective pair may be aligned with at least one electrode on the opposite jaw member. Each pair of electrodes on each jaw member may be disposed in substantially vertical registration with a corresponding pair of electrodes on the opposite jaw member. A series of leads may couple each electrode to an electrosurgical generator via at least one multiplexer coupled therebetween. The series of leads may be coupled to the multiplexer and the multiplexer controls electrosurgical energy to each electrode. The multiplexer may control at least one of current density and activation sequence of the electrosurgical energy to each electrode. The plurality of electrodes may be configured in a staggered arrangement with respect to one another on each jaw member.
The present disclosure relates also to a method of sealing tissue with a bipolar electrosurgical forceps. The method includes the steps of: providing a forceps having an end effector assembly with first and second jaw members including opposing inwardly-facing surfaces each including a plurality of electrodes disposed thereon. The plurality of electrodes on the inwardly facing surface of the first jaw member are in substantially vertical registration with the plurality of electrodes on the inwardly facing surface of the second jaw member to form an opposing electrode pair. Each electrode is individually configured to a source of electrosurgical energy. Additionally, the method includes the steps of grasping tissue between the jaw member and selectively applying electrosurgical energy to the electrodes according to an algorithm which controls the activation of each electrode.
In one embodiment, the method may further include the steps of: decreasing electrosurgical energy to at least one of the op posing electrode pairs; and increasing electrosurgical energy to at least one other opposing electrode pair. In addition, the method may further include the steps of applying electrosurgical energy by advancing in progression along respective opposing electrode pairs from a distal end of the end effector assembly to a proximal end of the end effector assembly.
Various embodiments of the subject instrument are described herein with reference to the drawings wherein:
This application incorporates by reference herein in its entirety commonly owned, concurrently filed, co-pending U.S. patent application Ser. No. ______ (attorney docket no.: 2886 PCT CIP II (203-3427 PCT CIP II) by Hammill et al entitled “ELECTRODE ASSEMBLY FOR TISSUE FUSION.”
Referring now to
More particularly, forceps 10 includes a shaft 12 which has a distal end 14 dimensioned to mechanically engage a jaw assembly 110 and a proximal end 16 which mechanically engages the housing 20. The shaft 12 may be bifurcated at the distal end 14 thereof to receive the jaw assembly 110. The proximal end 16 of shaft 12 mechanically engages the rotating assembly 80 to facilitate rotation of the jaw assembly 110. In the drawings and in the descriptions which follow, the term “proximal”, as is traditional, will refer to the end of the forceps 10 which is closer to the user, while the term “distal” will refer to the end which is further from the user.
Forceps 10 also includes an electrical interface or plug 300 which connects the forceps 10 to a source of electrosurgical energy, e.g., an electrosurgical generator 350 (See
Handle assembly 30 includes a fixed handle 50 and a movable handle 40. Fixed handle 50 is integrally associated with housing 20 and handle 40 is movable relative to fixed handle 50 to actuate a pair of opposing jaw members 280 and 282 of the jaw assembly 110 as explained in more detail below. The activation assembly 70 is selectively movable by the surgeon to energize the jaw assembly 110. Movable handle 40 and activation assembly 70 are preferably of unitary construction and are operatively connected to the housing 20 and the fixed handle 50 during the assembly process.
As mentioned above, jaw assembly 110 is attached to the distal end 14 of shaft 12 and includes a pair of opposing jaw members 280 and 282. Movable handle 40 of handle assembly 30 imparts movement of the jaw members 280 and 282 about a pivot pin 119 from an open position wherein the jaw members 280 and 282 are disposed in spaced relation relative to one another for approximating tissue 600, to a clamping or closed position wherein the jaw members 280 and 282 cooperate to grasp tissue 600 therebetween (See
It is envisioned that the forceps 10 may be designed such that it is fully or partially disposable depending upon a particular purpose or to achieve a particular result. For example, jaw assembly 110 may be selectively and releasably engageable with the distal end 14 of the shaft 12 and/or the proximal end 16 of shaft 12 may be selectively and releasably engageable with the housing 20 and the handle assembly 30. In either of these two instances, the forceps 10 would be considered “partially disposable” or “reposable”, i.e., a new or different jaw assembly 110 (or jaw assembly 110 and shaft 12) selectively replaces the old jaw assembly 110 as needed.
Referring now to
Each shaft 212a and 212b includes a handle 217a and 217b disposed at the proximal end 216a and 216b thereof which each define a finger hole 218a and 218b, respectively, therethrough for receiving a finger of the user. As can be appreciated, finger holes 218a and 218b facilitate movement of the shafts 212a and 212b relative to one another which, in turn, pivot the jaw members 280 and 282 from an open position wherein the jaw members 280 and 282 are disposed in spaced relation relative to one another for approximating tissue 600 to a clamping or closed position wherein the jaw members 280 and 282 cooperate to grasp tissue 600 therebetween. A ratchet 230 is typically included for selectively locking the jaw members 280 and 282 relative to one another at various positions during pivoting.
Typically, each position associated with the cooperating ratchet interfaces 230 holds a specific, i.e., constant, strain energy in the shaft members 212a and 212b which, in turn, transmits a specific closing force to the jaw members 280 and 282. It is envisioned that the ratchet 230 may include graduations or other visual markings which enable the user to easily and quickly ascertain and control the amount of closure force desired between the jaw members 280 and 282.
One of the shafts, e.g., 212b, includes a proximal shaft connector/flange 221 which is designed to connect the forceps 200 to a source of electrosurgical energy such as an electrosurgical generator 350 (
The jaw members 280 and 282 are generally symmetrical and include similar component features which cooperate to permit facile rotation about pivot 219 to effect the grasping of tissue 600. Each jaw member 280 and 282 includes a non-conductive tissue contacting surface 284 and 286, respectively, which cooperate to engage the tissue 600 during treatment.
As best shown in
As best shown in
The electrical paths 516 and 526 typically do not encumber the movement of the jaw members 280 and 282 relative to one another during the manipulation and grasping of tissue 400. Likewise, the movement of the jaw members 280 and 282 do not unnecessarily strain the electrical paths 516 and 526 or their respective connections 517, 527.
As best seen in
It is envisioned that one of the jaw members, e.g., 282, includes at least one stop member 235a, 235b (
As mentioned above, the effectiveness of the resulting micro-seal is dependent upon the pressure applied between opposing jaw members 280 and 282, the pressure applied by each electrode micro-sealing pad 500 at each micro-sealing site 620 (
As best shown in
As best shown in
The ring electrode 522 is connected to the electrosurgical generator 350 by way of a cable 526 (or other conductive path) which transmits a first electrical potential to each ring electrode 522 at connection 527. The post electrode 512 is connected to the electrosurgical generator 350 by way of a cable 516 (or other conductive path) which transmits a second electrical potential to each post electrode 522 at connection 517. A controller 375 (See
Moreover, a PCB circuit of flex circuit (not shown) may be utilized to provide information relating to the gap distance (e.g., a proximity detector may be employed) between the two jaw members 280 and 282, the micro-sealing pressure between the jaw members 280 and 282 prior to and during activation, load (e.g., strain gauge may be employed), the tissue thickness prior to or during activation, the impedance across the tissue during activation, the temperature during activation, the rate of tissue expansion during activation and micro-sealing. It is envisioned that the PCB circuit may be designed to provide electrical feedback to the generator 350 relating to one or more of the above parameters either on a continuous basis or upon inquiry from the generator 350. For example, a PCB circuit may be employed to control the power, current and/or type of current waveform from the generator 350 to the jaw members 280, 282 to reduce collateral damage to surrounding tissue during activation, e.g., thermal spread, tissue vaporization and/or steam from the treatment site. Examples of a various control circuits, generators and algorithms which may be utilized are disclosed in U.S. Pat. No. 6,228,080 and U.S. application Ser. No. 10/073,761 the entire contents of both of which are hereby incorporated by reference herein.
In use as depicted in
It is further envisioned that selective ring electrodes and post electrodes may have varying electric potentials upon activation. For example, at or proximate the distal tip of one of the jaw members, one or a series of electrodes may be electrically connected to a first potential and the corresponding electrodes (either on the same jaw or perhaps the opposing jaw) may be connected to a second potential. Towards the proximal end of the jaw member, one or a series of electrodes may be connected to a third potential and the corresponding electrodes connected to yet a fourth potential. As can be appreciated, this would allow different types of tissue sealing to take place at different portions of the jaw members upon activation. For example, the type of sealing could be based upon the type of tissues involved or perhaps the thickness of the tissue. To seal larger tissue, the user would grasp the tissue more towards the proximal portion of the opposing jaw members and to seal smaller tissue, the user would grasp the tissue more towards the distal portion of the jaw members. It is also envisioned that the pattern and/or density of the micro-sealing pads may be configured to seal different types of tissue or thicknesses of tissue along the same jaw members depending upon where the tissue is grasped between opposing jaw members.
From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, it is envisioned that by making the forceps 100, 200 disposable, the forceps 100, 200 is less likely to become damaged since it is only intended for a single use and, therefore, does not require cleaning or sterilization. As a result, the functionality and consistency of the vital micro-sealing components, e.g., the conductive micro-sealing electrode pads 500, the stop member(s) 235a, 235b, and the insulative materials 514, 535 will assure a uniform and quality seal.
Experimental results suggest that the magnitude of pressure exerted on the tissue by the micro-sealing pads 112 and 122 is important in assuring a proper surgical outcome, maintaining tissue viability. Tissue pressures within a working range of about 3 kg/cm2 to about 16 kg/cm2 and, preferably, within a working range of 7 kg/cm2 to 13 kg/cm2 have been shown to be effective for micro-sealing various tissue types and vascular bundles.
In one embodiment, the shafts 212a and 212b are manufactured such that the spring constant of the shafts 212a and 212b, in conjunction with the placement of the interfacing surfaces of the ratchet 230, will yield pressures within the above working range. In addition, the successive positions of the ratchet interfaces increase the pressure between opposing micro-sealing surfaces incrementally within the above working range.
It is envisioned that the outer surface of the jaw members 280 and 282 may include a nickel-based material or coating which is designed to reduce adhesion between the jaw members 280, 282 (or components thereof) with the surrounding tissue during activation and micro-sealing. Moreover, it is also contemplated that other components such as the shaft portions 212a, 212b and the rings 217a, 217b may also be coated with the same or a different “non-stick” material. Preferably, the non-stick materials are of a class of materials that provide a smooth surface to prevent mechanical tooth adhesions.
It is also contemplated that the tissue contacting portions of the electrodes and other portions of the micro-sealing pads 400, 500 may also be made from or coated with non-stick materials. When utilized on these tissue contacting surfaces, the non-stick materials provide an optimal surface energy for eliminating sticking due in part to surface texture and susceptibility to surface breakdown due electrical effects and corrosion in the presence of biologic tissues. It is envisioned that these materials exhibit superior non-stick qualities over stainless steel and should be utilized in areas where the exposure to pressure and electrosurgical energy can create localized “hot spots” more susceptible to tissue adhesion. As can be appreciated, reducing the amount that the tissue “sticks” during micro-sealing improves the overall efficacy of the instrument.
The non-stick materials may be manufactured from one (or a combination of one or more) of the following “non-stick” materials: nickel-chrome, chromium nitride, MedCoat 2000 manufactured by The Electrolizing Corporation of OHIO, Inconel 600 and tin-nickel. Inconel 600 coating is a so-called “super alloy” which is manufactured by Special Metals, Inc. located in Conroe Texas. The alloy is primarily used in environments which require resistance to corrosion and heat. The high Nickel content of Inconel 600 makes the material especially resistant to organic corrosion. As can be appreciated, these properties are desirable for bipolar electrosurgical instruments which are naturally exposed to high temperatures, high RF energy and organic matter. Moreover, the resistivity of Inconel 600 is typically higher than the base electrode material which further enhances desiccation and micro-seal quality.
One particular class of materials disclosed herein has demonstrated superior non-stick properties and-, in some instances, superior micro-seal quality. For example, nitride coatings which include, but not are not limited to: TiN, ZrN, TiAlN, and CrN are preferred materials used for non-stick purposes. CrN has been found to be particularly useful for non-stick purposes due to its overall surface properties and optimal performance. Other classes of materials have also been found to reducing overall sticking. For example, high nickel/chrome alloys with a Ni/Cr ratio of approximately 5:1 have been found to significantly reduce sticking in bipolar instrumentation.
It is also envisioned that the micro-sealing pads 400, 500 may be arranged in many different configurations across or along the jaw members 280, 282 depending upon a particular purpose. Moreover, it is also contemplated that a knife or cutting element (not shown) may be employed to sever the tissue 600 between a series of micro-sealing pads 400, 500 depending upon a particular purpose. The cutting element may include a cutting edge to simply mechanically cut tissue 600 and/or may be configured to electrosurgically cut tissue 600.
Moreover and as best shown in
Jaw members 710 and 720 operate in a similar fashion as described above with respect to
A series of individual leads 711a, 711b and 711c is connected to respective electrodes 712a, 712b and 712c on jaw member 710. Another series of leads 721a, 721b and 721c is connected to respective electrodes 722a, 722b and 722c on jaw member 720. The proximal ends of leads 711a-711c and 721a-721c are connected to a multiplexer (MUX) 920 which is, in turn, connected to electrosurgical generator 500 via lead 910. MUX 920 controls the electrosurgical energy to each electrode, e.g., 712a, which allows the generator 500 to automatically control the activation of individual electrodes 712a with respect to a particular sequence, a particular current density and/or a particular time. The MUX may also allow the user to selectively control the electrodes, e.g., 712a, depending upon a particular purpose or to achieve a desired surgical result.
It is also envisioned that the MUX may be configured to regulate electrode pairs, e.g., 712a and 722a, in a particular sequence, with a particular current density or for pre-set periods of time as prescribed by the generator 500 algorithm or selectively by the user. For example, during sealing it may be preferable to initially activate the distal-most pairs of electrodes 712c and 722c followed by the other electrode pairs, e.g., 712b and 722b, 712c and 722c, to progressively seal the tissue if the jaw members 710 and 720 close in a so-called “tip-biased” manner. If the jaw members 710 and 720 are configured to close in a so-called “heel-biased” manner or other particular manner, the MUX may be configured or regulated by the generator algorithm to control electrodes 712a-712c and 722a-722c differently. The MUX may also activate one electrode or a particular electrode pair at different or unequal current densities or graduated current densities depending upon a particular purpose.
As discussed above, each electrode, e.g., 712a, is designed to individually connect to the MUX 920 which, in turn, regulates the flow of electrosurgical energy from the generator 500 to the electrodes, e.g., 712a. The electrodes, e.g., 712a and 712f, may also be configured in pairs which together connect to the MUX 920 to regulate the sealing process depending upon a particular purpose. Moreover and as discussed above, the electrodes 712a-712f or electrode pairs may be activated in any envisioned fashion (i.e., in terms of pairings, sequence, current density, amount or time) to achieve a particular desired result and optimize sealing.
As can be appreciated, during activation, high frequency sequential switching between different pairs of electrodes regulates the sealing process to allow consistent and reliable seals to form for varying tissue types and thicknesses. It is envisioned that the MUX 920 may regulate the generator 500 to create seals in a progressive manner across or along the opposing jaw surfaces. The individual pairs of electrodes may be automatically or selectively activated sequentially, simultaneously or in any other manner to suit a particular surgical purpose. Although the time of the overall seal may increase due to various electrode pair switching algorithms, it is contemplated that more consistent current densities may be maintained across and along the entire sealing surface during the sealing process. It is envisioned that the frequency of switching between different pairs of electrodes may be increased until current fluctuations in the lead wires between the generator 500 and the multiplexer 920 become substantially equivalent to current fluctuations characteristic of a single pair of electrodes disposed on opposing jaw members 710 and 720, respectively.
It is envisioned that the bipolar forceps of the present disclosure reduces mechanical tolerance requirements of a bipolar electrosurgical forceps while maintaining or increasing current density by providing jaw members which are longer than those of the prior art. For example and as a result of the present disclosure, high frequency sequential switching between different pairs of electrodes and electrode surfaces may result in time-division multiplexing of the electrode activation process which, while lengthening the sealing time, enables design of a forceps 10 with a jaw member having a length longer than 60 mm (so far as is known, 60 mm represents current mechanical limits to electrode lengths). For example, one of the issues with manufacturing jaw members 710 and 720 with electrode lengths of 60mm or greater is that the required tolerances relating to so-called “flatness” and “parallelism” must be tightly controlled along and across the electrodes. As can be appreciated, very restrictive electrode surface flatness and parallelism tolerances increase production costs. As can be appreciated, flatness and parallelism tolerances are less severe when utilizing the electrode configurations of the present disclosure.
In addition, the bipolar forceps of the present disclosure provides jaw members having a plurality of electrodes on each jaw member to form an array of individual pairs of corresponding or counterpart electrodes so that the activation sequence and electrosurgical energy applied to each electrode or each individual pair of corresponding electrodes (whether adjacent or opposing) may be varied to maintain or increase pressure of the tissue during tissue sealing, thereby increasing tissue seal integrity.
It is also contemplated that the various aforedescribed electrode arrangements may be configured for use with either an open forceps as shown in
While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
The present application is a continuation-in-part (CIP) of PCT application Ser. No. PCT/US03/08146 entitled “BIPOLAR CONCENTRIC ELECTRODE ASSEMBLY FOR SOFT TISSUE FUSION” filed on Mar. 13, 2003 by Schechter et al., the entire contents of which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US03/08146 | Mar 2003 | US |
| Child | 11225260 | Sep 2005 | US |
