US20030130656A1 - Insulated surgical scissors including cauterizing tip - Google Patents

Abstract

An insulated surgical scissors including a cauterizing tip that permits a surgeon the ability to mechanically cut tissue that is purchased between the cutting blades of the scissors and to apply a cauterization current to a precise portion of the seized tissue, thereby minimizing inadvertent burning of surrounding tissue. Both monopolar and bipolar configurations of the insulated surgical scissors are provided.

Description

RELATED APPLICATIONS
• This application is a Continuation application of Co-Pending application Ser. No. 09/837,903, filed Apr. 19,2001 entitled INSULATED SURGICAL SCISSORS INCLUDING CAUTERIZING TIP, and whose entire disclosures is incorporated by reference herein.[0001]
FIELD OF THE INVENTION
• This invention relates generally to the field of insulated surgical scissors and more particularly to both monopolar and bipolar scissors constructions that can be specifically adapted for use in laparoscopic, endoscopic and open surgery surgical procedures.[0002]
BACKGROUND OF THE INVENTION
• Insulated forceps, biopsy devices and clamping devices having the capability of providing a coagulating function are known in the art. These devices provide a significantly different function and have different design considerations than insulated scissors of the type forming the subject matter of this invention.[0003]
• For example, forceps are principally designed to grip and hold tissue and/or organs during a surgical procedure; not to sever tissue between cooperation cutting edges of blades that move past each other to provide the severing operation, as in the operation of scissors within the scope of this invention. This prior art directed to the construction and design of insulated, cauterizing forceps are not relevant to the insulated scissors of this invention. Representative surgical forceps are disclosed in U.S. Pat. Nos. 5,217,460 (Knoepfler); 5,116,332 (Lottick); 5,026,370 (Lottick); 4,671,274 (Sorochenko); 4,890,610 (Kirwan, Sr., et al.); 5,147,357 (Rose, et al.); 4,375,218 (DiGeronimo); 4,128,099 (Bauer); 1,813,902 (Bovie).[0004]
• Biopsy instruments also provide a significantly different function, and have different design considerations than the insulated scissors of the type forming the subject matter of this invention. In particular, biopsy devices are designed to separate and remove (often within a closed compartment of the device) portions of body tissue, growths, etc. from a patient's body. In distinction to biopsy devices, the function of insulated scissors within the scope of this invention is to sever tissue or other body parts between relatively movable cutting blades, without necessarily having any separate capability to confine the severed tissue and/or body part and remove it from the patient's body. Thus, prior art directed to the construction and design of insulated, cauterizing biopsy devices are not relevant to the insulated scissors of this invention. Representative surgical biopsy devices are disclosed in the following publications: U.S. Pat. No. 5,373,854 (Kolozsi); U.S. Pat. No. 5,295,990 (Levin); and European Patent Application 0 593 929 A1 (United States Surgical Corporation).[0005]
• A wide variety of surgical “cut and coagulation” scissors also are known in the prior art, as exemplified by U.S. Pat. Nos. 5,573,534 (Stone); 5,356,408 (Rydell); 5,352,222 (Rydell); 5,342,381 (Tidemand); 5,234,453 (Smith, et al.); 5,171,256 (Smith, et al.); 5,147,356 (Bhatta); 4,499,899 (Lyons, III). As noted above, surgical scissors are utilized for purposes that are significantly different from the previously identified coagulating biopsy or forceps devices.[0006]
• John M. Levin, the inventor of the subject matter described and claimed herein also is the inventor of the insulated cut/coagulate surgical scissors disclosed in U.S. Pat. No. 5,827,281 (Levin), whose entire disclosure is incorporated by reference herein. The scissors disclosed in the '281 Levin patent have a monopolar or a bipolar construction, which can be used during laparoscopic, endoscopic and open surgery for mechanically/electrically cutting and coagulating tissue. The jaws of these surgical scissors are covered in their entirety by insulation except for selected portions along the cutting edges and the tips to minimize undesirable burning/cutting of surrounding tissue. The present invention relates to modified forms of the insulated scissors described in the Levin '281 patent.[0007]
• The apparatus disclosed by Stone is a bipolar electro surgical instrument comprising jaws fabricated from an insulating material having conductive pathways. These conductive pathways permit sparking between the pathways when the jaw members are open. As the jaw members are brought together, the insulating jaw member material blocks the electrical path between the conductive pathways to terminate electrical treatment of tissue trapped between the jaw members.[0008]
• The apparatus disclosed by the Rydell patents are surgical scissors with a bipolar coagulation feature. The scissors disclosed therein comprise a pair of opposed blade members pivotally joined to one another through an insulated bushing member. Each of the blade members comprises a blade support and a blade, each fabricated from a metal but yet separated by a dielectric bonding agent. Cutting is performed at the blade level and cauterization occurs through the passage of electricity from one blade support and through the tissue to the other blade support. In other words, the passage of electricity is not through either of the blades that cut the tissue. Instead, electricity flows from one blade support (above and below the cut made by the blades), through the tissue trapped between the blade members, and into the other blade support.[0009]
• The apparatus disclosed by Tidemand is a combination bipolar scissors and forceps instrument. The scissors disclosed therein comprises a pair of interfacing blade surfaces. Each of the interfacing blade surfaces comprises an insulative ceramic layer of approximately 0.020 inches. During scissoring action, a gap of approximately 0.040 inches is created between the interfacing scissors surfaces. Tidemand states that this gap is small enough to allow an RF current applied to the interfacing blade members to “bridge” the gap and effect a cauterization on any tissue trapped between the blades.[0010]
• The apparatus disclosed by Smith, et al. ('453) is a disposable laparoscopic scissors utilizing cobalt-based alloy scissor elements that can be double acting (two movable jaws) or single acting (a single movable jaw in combination with a fixed jaw) and includes a plastic shrink wrap applied to the aluminum tube.[0011]
• The apparatus disclosed by Smith, et al. ('256) is also a disposable laparoscopic scissors that can be double acting or single acting and includes plastic shrink wrap applied to the aluminum tube and portions of the actuation means at the working end of the instrument to electrically insulate the instrument.[0012]
• J The apparatus disclosed by Bhatta is a scissors-like surgical instrument with a cutting and cauterizing heat source such as a hot wire element or a laser transmission fiber carried in at least one of the jaws members.[0013]
• The apparatus disclosed by Lyons, III is a rotary cutting scissors for microsurgery that includes an internal fiber light source for illuminating the surgical area.[0014]
• Even in view of the above-described prior art disclosures, a need still exists for improved surgical scissors construction that allows the surgeon to cut tissue and to immediately coagulate the opening created by the cut while at the same time minimizing or eliminating any burning of surrounding tissue. In addition, it is important to be able to restrict the electric current flow through the patient's tissue when using such an apparatus.[0015]
SUMMARY OF THE INVENTION
• An apparatus for cutting and cauterizing tissue during surgery while minimizing electrical and thermal contact of the apparatus with surrounding tissue. The apparatus comprises: a pair of opposing electrically conductive cutting blades pivotally connected to allow for shearing action of any tissue confined between opposed cutting edges of the cutting blades wherein the blades have blunted tips and wherein the pair of opposing cutting blades are entirely covered with an electrically and thermally insulative material except at the blunted tips; and a power source coupled to at least one of said pair of opposing cutting blades for electrically and thermally energizing at least one of said pair of blades.[0016]
• An apparatus for cutting and cauterizing tissue during surgery while minimizing electrical and thermal contact of the apparatus with surrounding tissue. The apparatus comprises: a pair of opposing electrically conductive cutting blades pivotally connected to allow for shearing action of any tissue confined between opposed cutting edges of the cutting blades wherein the is entirely covered with an electrically and thermally insulative material including its blunted tip and the other one of the pair of opposing cutting blades is entirely covered with an electrically and thermally insulative material except at its corresponding blunted tip; and a power source coupled to at least one of the pair of opposing cutting blades for electrically and thermally energizing at least one of the pair of blades.[0017]
• An apparatus for cutting and cauterizing tissue during surgery while minimizing electrical and thermal contact of the apparatus with surrounding tissue. The apparatus comprises: a pair of opposing electrically conductive cutting blades pivotally connected to allow for shearing action of any tissue confined between opposed cutting edges of the cutting blades wherein the blades have blunted tips and wherein the pair of opposing cutting blades is entirely covered with an electrically and thermally insulative material except on confronting surfaces at the blunted tips; a power source having a power side that is electrically coupled to one of the pair of opposing cutting blades and having a ground side that is electrically coupled to the other one of the pair of opposing cutting blades for generating a cauterization current that flows through tissue trapped between the confronting surfaces at the blunted tips.[0018]
DESCRIPTION OF THE DRAWINGS
• Many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:[0019]
• FIG. 1 is a fragmentary, isometric view of a monopolar insulated surgical scissors of the present invention;[0020]
• FIG. 1A is an enlarged view of the working end of the insulated surgical scissors of FIG. 1;[0021]
• FIG. 2 is an enlarged, cross-sectional view of the insulated surgical scissors taken along line[0022]2-2 in FIG. 1A, but with the blades in a partially-closed position;
• FIG. 3 is an enlarged, cross-sectional view of the insulated surgical scissors taken along line[0023]3-3 in FIG. 1A;
• FIG. 4 is an enlarged, cross-sectional view of the insulated surgical scissors taken along[0024]4-4 in FIG. 1A, but with the blades in a partially-closed position;
• FIG. 5 is an enlarged, cross-sectional view of the working end of a second embodiment of the monopolar insulated surgical scissors, taken along a line corresponding to the location of line[0025]2-2 in FIG. 1A, whereby the blade tips do not pass when the blades are in a closed position;
• FIG. 6 is an enlarged, cross-sectional view of the working end of a third embodiment of the monopolar insulated surgical scissors, taken along a line corresponding to the location of line[0026]2-2 in FIG. 1 A, whereby the blade tips abut each other in the closed position;
• FIG. 7 is an enlarged, cross-sectional view, taken along line[0027]7-7 in FIG. 9, of the working end of a fourth embodiment of the monopolar insulated surgical scissors whereby a sliver on the inside surface of each blade is exposed;
• FIG. 8 is an enlarged, cross-sectional view of the working end of a fifth embodiment of the monopolar insulated surgical scissors, taken along a line corresponding to the location of line[0028]2-2 in FIG. 1A, whereby only one of the blades has an exposed tip;
• FIG. 9 is an enlarged, partial isometric view of the working end of the fourth embodiment of the monopolar insulated surgical scissors showing the position of an exposed sliver on the inside surface of the upper blade and an exposed sliver on the inside surface of the lower blade; alternatively, these slivers could be on the outside surface of the blades, as shown in phantom in the lower blade;[0029]
• FIG. 10 is an enlarged, cross-sectional view of the working end of the embodiment of FIG. 9 taken along line[0030]10-10 in FIG. 9;
• FIG. 11 is enlarged, partial isometric view of the working end of either a monopolar or a bipolar surgical scissors having the extreme tip on the inside surfaces of the blades exposed;[0031]
• FIG. 12 is an enlarged, cross-sectional view taken along line[0032]12-12—in FIG. 11 showing the blade tips overlapping and the scissors in a closed position;
• FIG. 13 is an enlarged, cross-sectional view of the blades in FIG. 11 including a setback feature at the extreme tip of the blades showing the blades in a closed position;[0033]
• FIG. 14 is an enlarged, cross-sectional view of the connecting pivot fastener taken along line[0034]14-14 in FIG. 15;
• FIG. 15 is an enlarged, side view of the working end of a bipolar configuration of the insulated surgical scissors; and[0035]
• FIG. 16 is an enlarged, cross-sectional view of the of the bipolar insulated surgical scissors taken along line[0036]16-16 in FIG. 15.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
• Referring now in greater detail to the various figures of the drawing wherein like reference characters refer to like parts, an insulated monopolar surgical scissors constructed in accordance with the present invention is shown generally at[0037]320 in FIG. 1. The insulated monopolarsurgical scissors320 comprises a pair of opposed cuttingblades322 and324.
• The insulated[0038]surgical scissors320 is electrically energized for accomplishing the coagulation of blood vessels and/or other tissue that have been severed during the cutting operation. In particular, thescissors320 comprises a monopolar configuration, i.e., electrical energy is delivered from a power source (not shown) via a first electrical conductor (also not shown) to thescissors blades322 and324 (each comprising a metal such as stainless steel for conducting electricity), with bothblades322 and324 being at the same voltage. The return for the electrical energy from thescissors320 is through the patient (not shown) to a large surface (e.g., a conducting plate, not shown) located underneath the patient and then back to the power source via a second electrical conductor (not shown) , as is well-known in the art, such as that shown in FIG. 1 of U.S. Pat. No. 5,827,281 (Levin), which has already been incorporated by reference in its entirety. In accordance with FIG. 1 of the '281 Levin patent, the first electrical conductor enters the insulatedsurgical scissors320 at the proximal end, i.e., adjacent an actuation/handle portion325 of thescissors320. The first conductor is fed through the insulatedsurgical scissors320 where the first conductor passes the electrical energy to theblades322 and324 via aconductive pivot fastener327.
• In one preferred embodiment of the invention, this pair of opposed cutting[0039]blades322 and324 are completely insulated, except for one or more surfaces at the distal end of thescissors320, as will be described in greater detail hereinafter. However, in all embodiments the opposed cuttingblades322 and324 of thescissors320 include rounded or blunted distal edges to preclude the cutting of tissue trapped between the blades at the distal end. The complete insulation may be accomplished by an electrically and thermally insulative layer329 (e.g., using a ceramic material or readily available liquid electrical insulation material) applied to eachblade322 and324 while masking the one or more surfaces to create the selected uninsulated (i.e., conductive) surfaces. Alternatively, instead of masking these surfaces, theinsulative layer329 can be applied to theblades322/324 in their entirety and then removed, e.g., by filing, grinding, etc., from the distal end regions that are intended to be conductive for providing the electrical cutting or cautery operation.
• In accordance with the broadest aspects of the invention, any or all surfaces at the distal end of one or both of the[0040]blades322 and324 can be made conductive to provide either an electrical cutting or cauterizing operation. To further explain, as shown in FIG. 1A, the inner side surface (326/328), the upper edge surface (330/332), the outer side surface (334/336), the lower edge surface (338/340), and the distal end surface (342/344) in the distal region of one or bothblades322 and324 can be conductive to provide an electrical cutting or cauterizing operation. To achieve mechanical cutting of the tissue between theblades322 and324, theblades322 and324 are closed by the surgeon using thehandle portion325 in a conventional manner. During closure, the exposed tips of theblades322 and324 approach each other (FIG. 2-partial closure) and then overlap during full closure (not shown) so that inside surfaces326 and328 are adjacent each other. FIGS.3-4 depict how the insulated proximal or back portion of theblades322 and324 approach each other and then overlap during closure.
• It should be understood that, alternatively, only one or more of such surfaces (i.e., the inner side surfaces[0041]326/328, the upper edge surfaces330/332, the outer side surfaces334/336, the lower edge surfaces338/340 and the distal end surfaces342/344, collectively referred to as the “candidate” surfaces) can be selectively conductive to provide a cauterizing operation.
• When the inwardly facing surfaces ([0042]326/328) at the distal ends of thecutting blades322/324 are electrically conductive to provide an electrical cutting or cauterizing operation, they are operated by either purchasing the tissue to be cut or cauterized between them or the cutting or cauterizing operation is carried out with thescissors320 in an open condition.
• It is within the scope of this invention to make any amount or all of the outer circumference of the distal tip portion, of either or both[0043]blades322/324, electrically conductive. However, it is important that confronting surfaces of the blades at the distal end be configured to be blunt, so as not to mechanically cut tissue that is positioned between theblades322/324 at the distal ends thereof.
• In the preferred embodiment of the[0044]invention320 the conductive region of the tip is located in a region which is no more than5 millimeters from the distal edge of theblades322/324 (i.e., from the distal end surfaces342/344 back towards the conductive pivot fastener327), and more preferably is in the forward, or most distal 1-3 millimeters of theblades322/324 (see FIG. 11).
• FIG. 5 depicts a similar type of monopolar scissors as shown in FIGS.[0045]1-4 but in the embodiment of FIG. 5, the uninsulated tip regions do not pass each other when thescissors320 is in its fully-closed position. Instead, thelower edge surface338 ofblade322 and thelower edge surface340 ofblade324 lie along the same plane P1 when the scissors are in a fully-closed position. As a result, the uninsulated tip regions act as a “clamp” for purchasing tissue and then, when electrically activated, the uninsulated tip region can either electrically cut or coagulate tissue. To prevent the uninsulated tip regions from passing each other, any number of well-known mechanisms, or their equivalents, can be used such as having thehandle portion325 comprise a stop to prevent the uninsulated tip regions from passing each other; or by configuring the proximal or back portion of eachblade322/324 to interact with each other to prevent the uninsulated tip regions from passing each other, or by configuring the tip regions so that they do not pass each other.
• FIG. 6 depicts another monopolar scissors wherein the uninsulated tip region of each[0046]blade322 and324 comprises abutting, or engaging,surfaces346 and348, respectively. Thus, thelower edge surface338 ofblade322 and thelower edge surface340 ofblade324comprise abutting surfaces346 and348, respectively, to prevent the overlapping of theblades322 and324 at the tips thereof.
• FIGS. 7 and 9-[0047]10 depict an alternative monopolar embodiment of the invention in which a verysmall sliver350, e.g., on the order of a millimeter, of conductive material extends along either the entire length or a fraction of the length of theinside surfaces326 and328 of theblades322 and324, respectively, or of theoutside surfaces334 and336 of theblades322 and324, respectively. Alternatively, thesliver350 can be on the inside surface or the outside surface of only one of theblades322 or324. When thesliver350 extends only over a fraction of the length ofblade322 and/orblade324, it preferably extends over a distal region thereof adjacent the conductive tip but does not include the distal end surfaces342/344.
• As stated above, the[0048]sliver350 can be on both the inside surfaces (326 and328) and/or the outside surfaces (334 and336) of one or bothblades322 and324. Preferably, however, thesliver350 is included on the inner confronting surfaces (i.e.,326 and328) of theblades322 and324 that are intended to provide a mechanical cutting operation.
• It also should be understood that injury tends to occur when conductive surfaces of the[0049]scissors320 that cannot be viewed by the surgeon inadvertently come in contact with undesired regions in the vicinity of the surgical sight. However, when aconductive sliver350 is provided along an outer edge (as shown in phantom by thereference number351 in FIG. 9) of one or both of theblades322/324, they are generally oriented so that the surgeon can see at least one of them while providing a cutting or cauterizing operation, thereby minimizing the likelihood that an inadvertent injury will be caused to the patient.
• FIG. 8 depicts another embodiment of the monopolar scissors wherein one of the blades, (e.g., blade[0050]322) is covered in its entirety with theinsulative layer329 whereas the tip region of theother blade324 comprises the selective uninsulated surfaces. Although all of the candidate surfaces at the tip ofblade324 are illustrated as being conductive, uninsulated surfaces, it is within the scope of this invention to make one or more, but less than all, of such candidate surfaces conductive.
• In summary, the distal tip section of[0051]blade322 and/or324 is provided with one or more conductive surfaces (i.e., candidate surfaces) to provide a cauterizing or cutting operation, and the variations of surfaces which can be made electrically conductive are the same as described above in connection with the earlier embodiments of this invention.
• The manner in which the[0052]blades322 and324 are operated by the surgeon is through the actuation of the handle portion325 (FIG. 1). It should be understood that scope of the present invention is not limited to employing any specific actuation/handle portion, and that any conventional actuation/handle portion for effecting relative movement of blades at the distal end of a surgical device (both laparoscopic and non-laparoscopic) can be used with the present invention, such as that set forth in U.S. Pat. No. 5,234,453 (Smith et al.), the entire disclosure of which is incorporated by reference herein. Therefore, a detailed explanation of the actuation/handle portion325 is omitted from this application.
• There is shown at[0053]420 in FIGS.11-12 an insulated surgical scissors having a pair ofjaws422 and424 electrically coupled in a bipolar configuration. A bipolar configuration means that each blade forms an electrode with one blade being at the voltage of a power source (not shown) while the other blade is electrically coupled to the ground side of the power source. FIG. 8 of U.S. Pat. 5,827,281 (Levin), whose entire disclosure has already been incorporated by reference herein, depicts the bipolar electrical activation of the working end. Hence, electrical energy flow is now confined to the following path: power source to oneblade424, (which comprises a metal such as stainless steel for conducting electricity) via a first electrical conductor (not shown), through the tissue (not shown) wedged between the pair ofblades422/424, out into the other blade422 (which comprises a metal such as stainless steel for conducting electricity) and then back to the power source via a second electrical conductor (not shown). As such, there is no conductive plate that the patient must lie on and there is no flow of current through the patient's body other than through the tissue between the blades.
• Actuation of the bipolar jaws by a handle portion (not shown) of the insulated surgical scissors is the same or similar to the[0054]handle portion325 described earlier with respect to the monopolar insulatedsurgical scissors320, and, as a result, is not explained any further herein.
• Like the monopolar insulated[0055]surgical scissors320, the bipolar insulated surgical scissors is completely insulated (e.g., using a ceramic material or readily available liquid electrical insulation material), both electrically and thermally, on all of its exposed surfaces. As such, aninsulative layer429 covers almost theentire scissors420. The only portions of the bipolar insulatedsurgical scissors420 that are not electrically and thermally insulated are confronting inner surfaces of theblades422 and424, discussed below.
• In a bipolar configuration, although electrical energy is easily conducted through both[0056]blades422 and424, there is no flow of electrical energy into, nor out of, any unexposed portion of the bipolarsurgical scissors420. It should be noted that the pivot point (not shown in FIG. 11) between the upper andlower blades422 and424 must be electrically and thermally insulated to ensure that there is no short that would cause the flow of electrical energy from the one blade (e.g.,424) to the other blade (e.g.,422) and thereby bypass the confronting inner surfaces of theblades422 and424.
• One way of providing this electrical/thermal insulation at the pivot point is to fully insulate the entire periphery of the[0057]blades422/424 in the region of the pivot point, including the inner surface of the passage for receiving the pivot pin. Such an arrangement is illustrated in FIG. 14 and will be discussed in greater detail in connection with the bipolar scissors configuration of FIGS.15-16.
• Moreover, since the exit flow of electrical energy, in the bipolar configuration, is confined to the confronting inner surfaces of the[0058]jaws422 and424 of thescissors420, the only portions of the scissors that conduct heat are these confronting inner surfaces. As such, any burning or smoking of tissue caused by thesurgical scissors420 being electrically active is restricted to tissue trapped between the confronting inner surfaces. Therefore, in the bipolar variants of this invention discussed below, the uninsulated conductive portions of the tip cannot include the entire exposed circumference since undesired shorting would occur. It is important that the cooperating conductive surfaces be “inner” conductive surfaces to avoid undesired arcing and burning of tissue.
• In a first embodiment of this bipolar[0059]surgical scissors420, all of the surfaces of theblades422 and424 are insulated, except for confrontinginner surfaces480 and482 at the distal end of theblades422 and424, respectively. In this connection, the confrontinginner surfaces480 and482 of theblades422 and424, respectively, preferably are configured with blunt and/or rounded surfaces to preclude the mechanical cutting of tissue disposed between them. As shown most clearly in FIG. 12, the tips of theblades422 and424 can be configured so thatconductive surfaces480 and482 of adjacent tips engage the tissue (not shown) along a plane P2 obliquely oriented to the elongate axis, A, of the scissors420 (FIG. 11).
• It should be noted that with the entirety of the[0060]blades422 and424 being insulated except for the confrontinginner surfaces480 and482, there is no concern for any shorting, i.e., electrical energy bypassing flow through the confrontinginner surfaces480 and482, if theback portion483 and485, respectively, of theblades422 and424 overlap before the confrontinginner surfaces480 and482 during closure.
• If desired, the confronting inner[0061]conductive surfaces480 and482 at the distal end of theblades422 and424 in the bipolar version of this invention can either be in the form of raised inner projections (not shown) or recessed grooves (FIG. 13). If these regions are in the form of raised projections, the mechanical cutting action of theblades422 and424 will take place until the raised projections engage each other. In particular, FIG. 13 depicts an embodiment similar to the embodiment of FIG. 11 but which includes uninsulated recessedgrooves484 and486 (also known as “set-backs”) in the distal tip regions. Thus, during closure, the recessedgrooves484 and486 form a small cavity for capturing tissue therein and wherein this tissue is exposed to the confronting innerconductive surfaces480 and482.
• FIGS.[0062]15-16 depict anadditional embodiment421 of this bipolar surgical scissors invention whereby the confronting inner surfaces engage the tissue along a plane P3 (FIG. 16) that is substantially perpendicular to the pivot axis (schematically depicted as “PA” in FIG. 16) of thescissors421. In particular, aslight sliver450 of conductive material can be provided along the inside cutting edges of thescissors421. In this embodiment, thescissors421 preferably is designed so that the entire length of theslivers450 of both cuttingblades422 and424 tend to engage each other at the same time, to thereby avoid undesired arcing. In this embodiment of the invention, thesliver450 can extend to the distal tip of eachblade422 and424, or can actually terminate short of the end surfaces442 and444. In this latter embodiment, the tips of theblades422/424 can be completely insulated with the entire cautery or cutting operation taking place in the region where theconductive slivers450 overlap.
• In the[0063]additional embodiment421, as shown most clearly in FIG. 15, the physical design ofblades422 and424 permits theconductive slivers450 to be brought together, whenever the surgical scissors are closed by the surgeon, such that the contact along the entire length of their corresponding cutting edges is simultaneous. In other words, eachblade422 and424 is angled so that the front edge portions make contact at the same time that the rear edge portions make contact. Should the rear edge portions make contact before the front edge portions, an electrical short would occur, causing electrical energy to flow across the rear edge portions and bypass flowing through any tissue trapped between the front edge portions.
• In a further embodiment of this bipolar surgical scissors invention is encompassed by the scope of this invention whereby the confronting inner surfaces engage the tissue along a plane that is substantially parallel to the pivot axis PA of the[0064]scissors421. FIG. 15 of U.S. Pat. No. 5,827,281 (Levin) depicts such a construction.
• It should be understood that it is also within the scope of that present invention that all of the bipolar embodiments discussed above could be designed with any one of the three tissue-engaging orientations, i.e., (1) engaging the tissue along a plane P2 obliquely oriented to the elongate axis, A, of the[0065]bipolar scissors420; (2) engaging the tissue along a plane P3 that is substantially perpendicular to the pivot axis PA of thebipolar scissors421; or (3) engaging the tissue along a plane that is substantially parallel to the pivot axis PA of thescissors421.
• The bipolar embodiments of the insulated scissors of this invention can be made by first completely insulating each of the[0066]blades422 and424, including the passage462 (FIG. 14) that is required to receive ascrew427 for pivotally attaching theblades422/424 together. Thescrew427 is then positioned through the insulated passage464. Thus, in this invention, it is not required that thescrew427 also be insulated, since the inner surface of the passage464 surface is insulated.
• It should be noted that in both the monopolar and bipolar scissors of this invention, the most desirable embodiments are those in which the exposed conductive areas are at the minimum required to provide the desired electrical cutting and/or cauterizing functions. In both the monopolar and bipolar scissors, minimizing the conductive area of the blades reduces the amount of current that is necessary to effect an electrical cutting or cauterizing operation. In the bipolar scissors of this invention, minimizing the conductive areas on the cutting blades provides the additional benefit of effectively controlling the flow of current through the tissue being electrically cut and/or cauterized.[0067]
• Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current or future knowledge, readily adopt the same for use under various conditions of service.[0068]

Claims (19)

I claim:

1. An apparatus for cutting and cauterizing tissue during surgery while minimizing electrical and thermal contact of said apparatus with surrounding tissue, said apparatus comprising:

a pair of opposing electrically conductive cutting blades pivotally connected to allow for shearing action of any tissue confined between opposed cutting edges of said cutting blades, said blades having blunted tips, said pair of opposing cutting blades being entirely covered with an electrically and thermally insulative material except at said blunted tips;

each of said cutting blades comprising an inner surface, an outer surface, an outer edge, the cutting edge and a distal edge surface, said blunted tip comprising said distal edge surface and forming a portion of said inner surface, said outer surface, said outer edge, and said cutting edge, said distal edge surface and said portions of said inner surface, said outer surface, said outer edge, and said cutting edge being uninsulated; and

a power source coupled to at least one of said pair of opposing cutting blades for electrically and thermally energizing at least one of said pair of blades.

2. The apparatus ofclaim 1 wherein said uninsulated portions of said inner surface, said outer surface, said outer edge and said cutting edge forming said blunted tip comprise lengths of less than 5 millimeters from said distal edge surface.

3. The apparatus ofclaim 1 wherein said uninsulated portions of said inner surface, said outer surface, said outer edge and said cutting edge forming said blunted tip comprise lengths of between 1 and 3 millimeters from said distal edge surface.

4. The apparatus ofclaim 1 wherein said cutting blades comprise respective confronting surfaces, said apparatus including a closed condition wherein said confronting surfaces form overlapping surfaces when the tissue being cut is trapped therebetween.

5. The apparatus ofclaim 1 wherein said apparatus includes a closed condition whereby said respective cutting edges of said cutting blades lie in a common plane and do not pass each other.

6. The apparatus ofclaim 5 wherein each of said cutting blades comprises a stop surface along said cutting edge, said stop surfaces of said cutting blades contacting to prevent said cutting blades from passing each other during closure of said apparatus.

7. An apparatus for cutting and cauterizing tissue during surgery while minimizing electrical and thermal contact of said apparatus with surrounding tissue, said apparatus comprising:

a pair of opposing electrically conductive cutting blades pivotally connected to allow for shearing action of any tissue confined between opposed cutting edges of said cutting blades, said blades having blunted tips, said pair of opposing cutting blades being entirely covered with an electrically and thermally insulative material except along predetermined segments of said cutting blades;

each of said cutting blades comprising an inner surface, an outer surface, an outer edge, the cutting edge and a distal edge surface, said predetermined segment comprising said outer surface closely adjacent said cutting edge; and

a power source coupled to at least one of said pair of opposing cutting blades for electrically and thermally energizing at least one of said pair of blades.

8. The apparatus ofclaim 7 wherein said predetermined segments further comprise said inner surface closely adjacent said cutting edge.

9. An apparatus for cutting and cauterizing tissue during surgery while minimizing electrical and thermal contact of said apparatus with surrounding tissue, said apparatus comprising:

a pair of opposing electrically conductive cutting blades pivotally connected to allow for shearing action of any tissue confined between opposed cutting edges of said cutting blades, said blades having blunted tips, said pair of opposing cutting blades being entirely covered with an electrically and thermally insulative material except along predetermined segments of said cutting blades;

each of said cutting blades comprising an inner surface, an outer surface, an outer edge, the cutting edge and a distal edge surface, said predetermined segment comprising said inner surface closely adjacent said cutting edge; and

a power source coupled to at least one of said pair of opposing cutting blades for electrically and thermally energizing at least one of said pair of blades.

10. The apparatus ofclaim 9 wherein said predetermined segments further comprise said inner surface closely adjacent said cutting edge.

11. The apparatus ofclaim 1 wherein said power source is coupled to the other one of said pair of opposing cutting blades for electrically and thermally energizing the other one of said pair of blades.

12. An apparatus for cutting and cauterizing tissue during surgery while minimizing electrical and thermal contact of said apparatus with surrounding tissue, said apparatus comprising:

a pair of opposing electrically conductive cutting blades pivotally connected to allow for shearing action of any tissue confined between opposed cutting edges of said cutting blades, said blades having blunted tips, said pair of opposing cutting blades being entirely covered with an electrically and thermally insulative material except on segments of confronting surfaces at said blunted tips;

each of said cutting blades comprising an inner surface, an outer surface, an outer edge, the cutting edge and a distal edge surface, said blunted tip comprising said distal edge surface and forming a portion of said inner surface, said outer surface, said outer edge, and said cutting edge, each of said segments comprising the distal end of said inner surface and being uninsulated; and

a power source having a power side that is electrically coupled to one of said pair of opposing cutting blades and having a ground side that is electrically coupled to the other one of said pair of opposing cutting blades for generating a cauterization current that flows through tissue trapped between said confronting surfaces at said blunted tips.

13. The apparatus ofclaim 12 wherein said pivotal connection is electrically insulated to prevent the passage of current from one of said opposing cutting blades into the other one of said opposing cutting blades.

14. The apparatus ofclaim 12 wherein said segment comprises a length of less than 5 millimeters from said distal edge surface.

15. The apparatus ofclaim 12 wherein said confronting surface at said blunted tip comprises lengths of between 1 and 3 millimeters from said distal edge surface.

16. The apparatus ofclaim 13 wherein each of said pair of opposing blades is formed so that when said apparatus is closed said cutting edges make contact nearly simultaneously along the length of said cutting edges.

17. The apparatus ofclaim 12 wherein said apparatus includes a elongate axis and wherein said cutting blades purchase tissue along a plane that is obliquely oriented to said elongate axis.

18. The apparatus ofclaim 12 wherein said apparatus comprises a pivot axis and wherein said cutting blades purchase tissue along a plane that is substantially perpendicular to said pivot axis.

19. The apparatus ofclaim 12 wherein said apparatus comprises a pivot axis and wherein said cutting blades purchase tissue along a plane that is substantially parallel to said pivot axis.

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