Abstract:
A surgical instrument is provided having a shaft with a handpiece at a proximal end and a grasping device at the distal end. The grasping device has a first jaw element and a second jaw element pivotably coupled thereto and selectively pivotable between open and closed positions. The instrument also includes a cutting device having a first cutting element and a second cutting element pivotably coupled to the first cutting element. The cutting device is movable between a retracted position wherein it is positioned within the shaft and an extended position wherein it is disposed at the distal end of the shaft. When in the extended position, the cutting elements are coupled to the respective jaw elements for movement therewith between open and closed positions. Also provided is a method for surgically manipulating tissue using such a device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of Provisional application Serial No. 60/323,156, filed Sep. 18, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to surgical forceps and scissors, and in particular, to a combination bipolar forceps and scissors surgical instrument. 
     2. Description of the Background Art 
     The utility of a surgical implement for performing both tissue cutting and coagulation has been identified and addressed previously by a number of designs. U.S. Pat. Nos. 4,655,216, 5,445,638, 5,458,598, and 5,573,535 all describe bipolar coagulating instruments with separately actuable single-blade cutting mechanisms. The single cutting blades featured in these designs lack precision due to the tendency of the blade to displace tissue from the grasper jaws while cutting tissue. Further, these designs expose sharpened portions of the cutting blade to tissue outside the grasper jaws, which creates the risk of inadvertent cutting of tissue and structures surrounding the intended treatment sight. Durability and longevity of the cutting blade can also be an issue with this cutting mechanism since it relies greatly on the sharpness of the delicate cutting edge. Further, the single-blade cutting mechanism suffers when compared to a conventional surgical scissors in terms of functionality. 
     Previous attempts at constructing combination bipolar forceps and scissors devices involved either segmenting the grasper jaws into a distal grasping and coagulating portion and a proximal shearing scissors portion, or employing two independent mechanisms for the graspers and scissors. The former approach, which is described in U.S. Pat. Nos. 5,342,381, 5,462,546, and 6,206,877 results in a device with relatively small grasping and coagulating surfaces and scissors mechanisms. This limits the area and thickness of tissue that can be coagulated and/or transected by the device. Further, because the scissor blades are fixed in place, it is possible to unintentionally cut tissue that has not been coagulated if great care is not taken when grasping tissue with the distal forceps portion of the jaw. 
     Designs featuring independent grasping and scissor mechanisms as described in U.S. Pat. No. 5,964,758 are mechanically complex. The scissor mechanisms are either permanently installed, which limits their utility as an a traumatic grasper or coagulating forceps, or controlled by a separate mechanism that further complicates their application. 
     Further, no forceps and scissor combinations previously described takes advantage of an offset electrode arrangement which greatly reduces the area of tissue coagulated during application of bipolar energy, and results in significantly reduced levels of undesirable collateral tissue damage. In conventional prior-art bipolar forceps, current  6  from the electrosurgical generator is passed between jaws  4  and  5  through tissue  7  captured between the jaws, as shown in FIGS. 1 a  and  1   b . The arrangement of the electrodes in this opposing fashion causes some of the electrosurgical current  8  flowing between the jaws to pass through tissue outside of the jaws, thus causing collateral tissue destruction. Offset electrode technology is disclosed in U.S. Pat. No. 5,403,312, which is incorporated herein by reference. 
     U.S. Pat. No. 5,984,938 describes a forcep concept with deployable scissor inserts; however, this design describes a conventional mechanical grasper with sprung jaws, not a bipolar coagulating forcep with a hinged jaw. Further, the inserts described do not possess a sharpened leading edge, which would allow them to be used as tissue transectors. 
     Finally, the straight and un-tapered form of the jaws described in all of the previous disclosures limits user visibility of the distal tip, compromises their ability to access recessed structures, and prevents them from effectively being used as a mechanical dissector. 
     Thus, there is a need for an improved combination bipolar forceps and scissor device that overcomes deficiencies of prior art devices. 
     SUMMARY OF THE INVENTION 
     A surgical instrument is provided including a shaft having a proximal end and a distal end, a handpiece disposed at the proximal end of the shaft, and a grasping device disposed at the distal end of the shaft, and having a first jaw element and a second jaw element pivotally coupled to the first jaw element and selectively pivotable relative to the first jaw element between an open position and a closed position. The instrument also includes a cutting device having a first cutting element and a second cutting element pivotally coupled to the first cutting element. The cutting device is movable between a retracted position wherein it is positioned within the shaft and a extended position wherein it is disposed at the distal end of the shaft. When the cutting device is in the extended position, the first and second cutting elements are coupled to the first and second jaw elements respectively for movement therewith between open and closed positions. 
     In one embodiment the instrument further includes a grasper activation assembly for selectively moving the grasping device between the open and closed positions, and a cutting device activation assembly for selectively moving the cutting device between the retracted and extended positions. In yet another embodiment, the grasping activation assembly further includes a grasping activator element associated with the handpiece, and grasping activation coupling elements for coupling the grasping activator element with the grasping device so that selective movement of the grasping device between the open and closed positions can be accomplished by manipulating the grasping activator element. The cutting activation assembly also further comprises a cutting activator element associated with the handpiece, and cutting activator coupling elements for coupling the cutting activation element with the cutting device so that selective movement of the cutting device between the retracted and extended positions can be accomplished by manipulating the cutting activator element. In yet another embodiment, the grasping activation coupling elements include an elongate element positioned within the shaft, wherein longitudinal movement of the elongate element along the axis of the shaft causes the second jaw element to pivot relative to the first jaw element between the open and closed positions. Further, the cutting activation elements include an elongate element positioned within the shaft, wherein longitudinal movement of the elongate element along the axis of the shaft causes the cutting device to move between the retracted and extended positions. 
     In alternate embodiments, the instrument further includes at least one pair of bipolar electrodes contained within the first and second jaw elements respectively, the arrangement being such that when the grasping device is in the closed position, the electrodes are substantially facing towards one another and either substantially offset from one another or substantially opposing one another. 
     In yet another embodiment, the first and second jaw elements have first and second channels therein respectively. When in the extended position, the first and second cutting elements are positioned within the first and second channels respectively. In yet another embodiment, the instrument further includes means for impeding rotation of the grasping element when in the closed position. In an alternate embodiment, the first and second cutting elements have first and second protrusions respectively that, when the cutting device is in the extended position, are received within first and second recesses in the first and second grasping elements respectively. 
     Also provided is a surgical instrument including a shaft having a proximal end and a distal end, a handpiece disposed at the proximal end of the shaft, and a grasping device disposed at the distal end of the shaft having first and second jaw elements pivotally coupled to one another and pivotable relative to one another between opened position and a closed positions. The instrument further includes a cutting device having a first cutting element and a second cutting element pivotally coupled to the first cutting element. The cutting device is movable between a retracted position wherein it is positioned within the shaft and a extended position wherein it is disposed at the distal end of the shaft. When the cutting device is in the extended position, the first and second cutting elements are coupled to the first and second jaw elements respectively for movement therewith between open and closed positions, and at least one of said first and second cutting elements has a sharpened leading edge capable of dissecting tissue when the cutting device is moved from the retracted position to the extended position. 
     A method for surgically manipulating tissue is also provided including the steps of grasping a portion of tissue using a grasping device positioned at a distal end of a shaft of a surgical instrument, coagulating the grasped tissue by applying bipolar electrical energy to bipolar electrodes within the grasping device, and cutting the tissue by deploying a cutting device from a first position wherein it is retracted within the shaft of the surgical instrument, to a second position wherein it extends into the grasping device. 
     These and other features and advantages of the present invention will become apparent from the following more detailed description, when taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 a  is a side view of a prior art bipolar grasper; 
     FIG. 1 b  is an end elevational view as seen along view line  1   b — 1   b  of FIG. 1 a  with arrows indicating current flow between the forceps grasping jaws; 
     FIG. 2 a  is a side view of one embodiment of a combination scissors and bipolar forceps surgical instrument according to the present disclosure connected to a bipolar electrosurgical generator; 
     FIG. 2 b  is a cutaway view of the handle of the device illustrated in FIG. 2 a  showing the internal mechanisms; 
     FIG. 3 is an exploded perspective view of the distal end of one embodiment of the present invention; 
     FIG. 4 a  is an enlarged perspective view of the distal end of the embodiment of FIG. 3 with the grasping device closed and the cutting device retracted; 
     FIG. 4 b  is an enlarged perspective view of the distal end of the embodiment of FIG. 3 with the grasping device closed and the cutting device deployed; 
     FIG. 5 a  is an enlarged perspective view of the distal end of the embodiment of FIG. 3 with the grasping device open and the cutting device retracted; 
     FIG. 5 b  is an enlarged perspective view of the distal end of the embodiment of FIG. 3 with the grasping device open and the cutting device deployed; 
     FIGS. 6 a - 6   e  illustrate alternate embodiments of the grasping device; 
     FIGS. 7 a - 7   d  are elevational views illustrating other embodiments of the leading edges of the cutting device; 
     FIGS. 8 a - 8   c  are plan views of the grasping faces of the jaws showing various embodiments of the offset electrode arrangement; 
     FIGS. 9 a - 9   c  are transverse cross-sectional views of the grasper jaws of FIGS. 8 a - 8   c , respectively, further illustrating the offset electrode arrangements; 
     FIGS. 10 a - 10   b  are elevational views of various embodiments of a handpiece; 
     FIGS. 11 a - 11   d  illustrate one method of operation of an embodiment of the present invention; 
     FIGS. 12 a - 12   d  illustrate an alternate method of operation of an embodiment of the present invention; and 
     FIGS. 13 a  and  13   b  are transverse cross-sectional views of alternate embodiments of the grasping device illustrating possible cutting device retaining mechanisms. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Before explaining the present invention in detail, it should be noted that the invention is not limited in its application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description, because the illustrative embodiments of the invention may be implemented or incorporated in other embodiments, variations and modifications, and may be practiced or carried out in various ways. Furthermore, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative embodiments of the present invention for the convenience of the reader and are not for the purpose of limiting the invention. 
     Bipolar electrosurgical tools are widely used in both open and endoscopic surgery for cutting, vaporizing, and coagulation tissue. The present disclosure provides a surgical instrument that can perform several functions required during laparoscopic surgery. Beyond the creation and maintenance of hemostasis, there are a variety of mechanical functions, including tissue grasping, tissue dissecting, mechanical spreading, and tissue cutting which are desirable. The design of the present invention provides these functions in a single instrument. 
     Referring now to FIG. 2 a , a combination bipolar forcep and scissor surgical instrument  1  is shown connected to a common electrosurgical generator  2 . Current flow through the bipolar electrodes housed within the jaws of the instrument can be controlled by a foot pedal  3  attached to the generator. Surgical instrument  1  comprises a handle  26 , a shaft  27  having a proximal end  103  and a distal end  104  and a lumen extending therethrough, and an end effector such as the illustrated grasping device  28  extending from the distal end of shaft. 
     Although numerous arrangements of bipolar electrodes are suitable for use with the present invention, reducing the level of undesirable collateral tissue destruction caused by bipolar forceps is important, and can be accomplished by arranging the electrodes in a fashion that limits the flow of current outside the jaws. In contrast to prior art arrangements such as that shown in FIG. 1 b , FIGS. 8 a - 8   c  and  9   a - 9   c  show possible arrangements of electrodes that accomplish this by offsetting the opposing poles of the electrode pairs. FIGS. 8 a - 8   c  are plan views of the grasping faces  80  of jaws  12 ,  13  of the grasping device  28 . FIGS. 9 a - 9   c  show a cross-sectional view of these grasping devices respectively. Electricity  9  passing through tissue  10  captured between the jaws  12 ,  13  stays primarily within the cross section of the jaws, thus limiting collateral thermal injury. FIGS. 6 a - 6   e , illustrate possible grasper jaw forms that are suitable for the present invention. It should be understood, however, that jaw form is typically a matter of user preference and surgical application, and that any jaw form, such as straight, curved, tapered, or non-tapered, may be used in conjunction with the present disclosure. The offset electrode arrangement disclosed herein is applicable to any of these forms. 
     FIGS. 3,  4   a ,  4   b ,  5   a , and  5   b  illustrate the distal end of one embodiment of the present invention that provides a highly functional grasper and dissector that can quickly and simply be converted to a scissor by way of finger mechanisms on the handpiece. Included in this embodiment are a grasper device  28  including a lower jaw element  12  having a slot or channel  12 A therein, and a upper jaw element  13  having a slot or channel therein  13 A, a cutting or scissor device including upper and lower scissor elements (i.e., blades)  14 A and  14 B, a jaw drive shaft  15 , a scissor drive shaft  16 , and pivot pins  17   a ,  17   b  and  18  for attaching the upper jaw to the lower jaw and the upper scissor element to the lower scissor element respectively. Pivot pins  17   a  and  17   b  may be independent components or integral elements of either the upper jaw  13  or lower jaw  12 . Likewise, pivot pin  18  may be a separate component or an integral component of either of the scissor blades  14 A or  14 B. The lower jaw  12  is mounted to shaft  27  that houses the jaw drive shaft  15  and scissor drive shaft  16 . The upper jaw is opened by longitudinal distal extension of the jaw drive shaft  15  as indicated by the arrow in FIG. 5 a . The scissor blades are driven forward into the jaws by longitudinal distal extension of the blade drive shaft  16  as indicated by the arrow in FIG. 4 b . The upper scissor blade insert  14 A is pinned to the lower scissor blade insert  14 B by pin  18  at a point that permits free pivoting of the upper blade when the scissor blades are deployed into the grasper jaws. The slots in both the upper and lower jaw accommodate the scissor blades when they are deployed, and include a cutting device retaining mechanism (described more fully below) that couples the scissor blades to the respective jaws of the grasping device for pivotal movement therewith. Thus, with the scissor blades deployed, the mechanism that opens and closes the grasper blades can be similarly used to move the scissor blades between similar open and closed positions, allowing them to be used as a scissor. 
     FIG. 4 a  shows the distal end of the combination bipolar forcep and scissor surgical instrument where the grasping device  28  is in the closed position, and the scissor device  102  is in the closed position and retracted within the shaft  27 . FIG. 4 b  similarly illustrates both the grasper and scissor devices in the closed position, but with the scissor device in the deployed or extended position where it is positioned within the slots  12 A,  13 A in the grasper device  28 . In this position the scissor device  102  is positioned substantially within the grasper device so that it cannot cut surrounding tissue, but a sharp leading edge  103  of the scissor device may cut any tissue that is being grasped by the grasping device as the scissor device is deployed from the retracted position to the extended position, as will be described in further detail with reference to FIGS. 11 a - 11   d . As indicated above, the scissor device is moved between the retracted position and the extended or deployed position by moving the scissor drive shaft  16  longitudinally forward relative to the outer shaft  27 , as shown by the arrow in FIG. 4 b.    
     FIG. 5 a  illustrates the scissor device  102  in the retracted position, and the grasping device  28  in the open position, which is accomplished by moving the jaw drive shaft  15  longitudinally forward relative to the outer shaft  27 , as shown by the arrow in FIG. 5 a . In this position, the instrument  1  can be used to grasp tissue or the like between the upper and lower jaws  13 ,  12  of the grasper device  28 . Finally, FIG. 5 b  shows the grasping device in the open position, and the scissor device  102  deployed or extended and also in the open position. In this configuration the instrument  1  can be used as a typical scissor would be. 
     Several different cutting device retaining mechanisms  110  can be used to couple the scissor blades to the jaws when the scissor device is in the deployed position. As illustrated in FIGS. 4 a - 4   b , and  5   a - 5   b  the outer sections of the leading edges  103  of both scissor blades  14 A,  14 B can be equipped with an extension  19  that fits into corresponding holes or cavities in the front regions  105  of the jaws to hold the blades in place. An advantage to this method is that the tapered design of the extension and receptacle cavities will allow the blades to properly mate with the jaws even when the jaws are slightly open or engaging tissue. An alternative method illustrated in FIG. 13 a  involves using an L-shaped channel  130  on the grasper jaw that captures horizontal ridges  132  on the outer edge of the blade inserts. Yet another method illustrated in FIG. 13 b  involves a tapered channel  135  in the jaw that is wider at the bottom than the top and employing cutting blade inserts which are similarly formed tapered  136  with wider outer edges tapering to a narrower profile near the shearing surface  137 . Those skilled in the art will understand that various other configurations are also possible. 
     Referring now to FIGS. 7 a  through  7   d , a variety of edge forms and different angles on the leading edges  700 A,  700 B of the scissor blade inserts may be employed to increase cutting efficacy during blade deployment. Angled blades as illustrated in FIGS. 7 a  and  7   b  can increase exposure of the tissue to the blades. In both of these arrangements, the blades may be equal length or one of the blades may be slightly longer, thus reducing the profile of the cutting element and reducing tissue resistance to cutting. Notched arrangements as illustrated in  7   c  and  7   d  can also reduce cutting resistance by doubling the cutting edge exposed to the tissue. 
     Referring back to FIGS. 2 a  and  2   b , the surgical instrument of the present invention includes a handle  26  coupled to a proximal end  103  of the shaft  27  through which the surgeon manipulates the grasping and/or cutting devices that are positioned at the distal end of the instrument. A rotating knob  20  is directly coupled to both the shaft  27  and the scissor and jaw drive shafts and can be used to rotate the jaw mechanisms to any angle. Mechanisms such as a compression ring in the handpiece associated with this rotating collar can be included to resist unwanted jaw rotation once the trigger mechanism is compressed. Trigger mechanism/finger ring  22  is used to open and close the grasper jaws via direct coupling to the jaw drive shaft. Optimally, this finger ring should accommodate a wide range of hand sizes. Ratchet button  21  enables or disables a jaw ratchet which can be used to lock the position of the jaws relative to each other. When in the active position, teeth in the ratchet button progressively interfere with teeth in the internal portion of the finger ring, preventing reverse motion of the finger ring and associated opening of the jaws. Movement of the ratchet button to the inactive position disengages the ratchet teeth from the teeth in the handle and allows free motion of the finger ring. The cutting mechanism drive lever  23  is coupled to the scissor drive shaft  16  through coupling lever  23 A and is used to distend the scissor inserts into slots within the grasper blades. The position of a locking button  24  determines whether the blades will be locked into place upon full extension or return to their resting, stowed position in the instrument shaft after the lever is released. A spring  23 B provides tension on the coupling lever  23 A which will aid in pulling the scissor mechanism back toward the handle and into its retracted position. 
     FIG. 10 a  illustrates an alternate embodiment of the handpiece in which the cutting mechanism drive is accomplished with a sliding button. In this manifestation, locking of the blades in place can be achieved with a detent position at the end of the throw which would allow the blades to be locked in place by an upward or downward manipulation of the lever. FIG. 10 b  illustrates yet another alternate embodiment of the handpiece in which an in-line/barrel form of handpiece is used. Those skilled in the art will understand that various other configurations of handpieces and control mechanisms are also possible. 
     Referring again to FIG. 2, exiting the bottom of the handpiece is a bipolar cable  40  suitable for coupling to a bipolar electrosurgical generator  2 . In normal application, the users index finger may be employed to adjust the rotary knob  20  and set the ratchet enable/disable button  21 . The users thumb may be used to work the cutting mechanism drive lever  23  or slide and set the scissor lock enable disable button  24 . The middle, ring, or optionally little fingers may be accommodated by and used to manipulate the trigger mechanism  22 . 
     Referring now to FIGS. 11 a - 11   d , and  12   a - 12   d , methods for using the disclosed surgical instrument will now be described in greater detail. According to one method, the grasping device  28  of the surgical instrument is placed in the open position while the cutting device (not shown) is maintained in the retracted position within the shaft  27 , as shown in FIG. 11 a . Tissue  120  is then grasped by placing the jaws  12 ,  13  around tissue  120  and subsequently moving the jaws to the closed position shown in FIG. 11 b  by longitudinally retracting the jaw drive shaft  15 , causing the upper jaw  13  to pivot relative to the lower jaw  12  to the closed position. Current is then applied to the bipolar jaws, thereby coagulating the tissue captured between the grasper jaws. Subsequently, the cutting device  102  can be deployed within the grasping device as shown in FIG. 11 c  to transect the desiccated tissue. The cutting device can once again be retracted and the grasping device opened to remove the instrument from the tissue  120  (FIG. 11 d ). 
     Alternatively, once the tissue has been grasped as shown in FIG. 11 b  and coagulated, the grasping device can be opened to release the tissue, and re-closed again in order to deploy the cutting device  102  within the grasper device as shown in FIG. 12 a . Once the cutting device is deployed, the grasping device is re-opened again, this time in conjunction with the blades of the cutting device as shown in FIG. 12 b . The tissue can then be re-grasped, causing cutting of the coagulated tissue by a scissor action, as shown in FIG. 12 c . The grasping device is once again opened to finally release the cut tissue (FIG. 12 d ). 
     Although exemplary embodiments and methods for use have been described in detail above, those skilled in the art will understand that many variations are possible without departing from the spirit and scope of the invention, which is limited only by the appended claims.