Abstract:
The present disclosure describes a surgical device with a body portion defining a longitudinal axis, a tool assembly including an anvil, a cartridge assembly housing a plurality of staples, a dynamic clamping member movable relative to the tool assembly to eject the staples, and an articulation and firing actuator extending at least partially through the body portion and the tool assembly. The tool assembly is pivotally attached to the body portion for movement from a position aligned with the longitudinal axis to a position oriented at an angle thereto. The articulation and firing actuator extends at least partially through the body portion and the tool assembly, is operably associated with the dynamic clamping member and the tool assembly, and is movable in relation thereto to selectively pivot the tool assembly relative to the body portion and move the dynamic clamping member relative to the tool assembly to eject the staples.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Divisional Application of U.S. patent application Ser. No. 10/529,568, filed on Mar. 28, 2005, which is a National Stage Application of PCT/US03/31653, filed on Oct. 6, 2003 under 35 U.S.C. §371(a), which claims priority from U.S. Provisional Patent Application Ser. No. 60/416,056, filed Oct. 4, 2002, entitled “Tool Assembly for Surgical Stapling Device,” now expired, the entire contents of each being incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates generally to a surgical tool assembly for manipulating and/or applying fasteners to tissue. More specifically, the present disclosure relates to a surgical tool assembly having a pair of jaws including a unique approximation mechanism to facilitate improved clamping and manipulation of tissue. 
         [0004]    2. Background of the Related Art 
         [0005]    Surgical staplers and tool assemblies for clamping tissue between opposed jaw structure of a tool assembly and thereafter fastening the clamped tissue are well known in the art. These devices may include a knife for incising the fastened tissue. Such staplers having laparoscopic or endoscopic configurations are also well known in the art. Examples of endoscopic surgical staplers of this type are described in U.S. Pat. Nos. 6,330,965, 6,250,532, 6,241,139, 6,109,500 and 6,079,606, all of which are incorporated herein by reference in their entirety. 
         [0006]    Typically, such staplers include a tool member or assembly having a pair of jaws including a staple cartridge for housing a plurality of staples arranged in at least two laterally spaced rows and an anvil which includes a plurality of staple forming pockets for receiving and forming staple legs of the staples as the staples are driven from the cartridge. The anvil and cartridge are pivotally supported adjacent each other and are pivotable in relation to each other between open and closed positions. In use, tissue is positioned between the jaws in the open position and the jaws are pivoted to the closed position to clamp tissue therebetween. 
         [0007]    One problem associated with conventional staplers and tool assemblies is that as the anvil and cartridge pivot in relation to each other, closure occurs first at the proximal end of the jaws and thereafter at the distal end of the jaws. This sequence of jaw closure has the effect of moving tissue positioned between the jaws towards the distal end of the jaws, thus, forcing tissue from the jaws. 
         [0008]    During laparoscopic or endoscopic procedures, access to a surgical site is achieved through a small incision or through a narrow cannula inserted through a small entrance wound in a patient. Because of the limited area available to access the surgical site, endoscopic staplers are sometimes used to grasp and/or manipulate tissue. Conventional staplers having an anvil or cartridge mounted to a fixed pivot point which are pivotable to a closed position are not particularly suited for grasping tissue because only a limited clamping force is produced at the distal end of the jaws. 
         [0009]    Accordingly, a need exists for an endoscopic surgical stapling tool member or assembly having pivotal jaws which can be operated to effectively grasp, manipulate and/or fasten tissue, including with the end of the jaws, without, or while minimizing, distal movement of the tissue positioned between the jaws. 
       SUMMARY 
       [0010]    In accordance with the present disclosure, a tool assembly having a pair of jaws is disclosed. Each of the jaws has a proximal end and a distal end and the first jaw is movable in relation to the second jaw between a spaced position and an approximated position. First and second cam followers are supported on the first jaw. An approximation member is movable in relation to the first jaw and includes at least one cam surface positioned to engage the first and second cam followers. The approximation member is movable in relation to the first jaw to move the at least one cam surface in relation to the first and second cam followers to effect movement of the first and second jaws from the spaced position to the approximated position. The at least one cam channel is configured to approximate the distal ends of the first and second jaws prior to approximation of the proximal ends of the first and second jaws. By approximating the distal ends of the first and second jaws first, tissue positioned between the jaws is not pushed forward within the jaws during closure of the jaws. Further, the jaws are better able to grip and manipulate tissue using the distal ends of the jaws. 
         [0011]    Preferably, the first jaw includes an anvil and the second jaw includes a cartridge assembly housing a plurality of staples. In a preferred embodiment, the at least one cam surface includes first and second cam channels, and the approximation member includes a flat plate having the cam channels formed therein. The first jaw includes a longitudinal slot formed in its proximal end and the approximation member is being slidably positioned in the longitudinal slot. The first and second cam followers are supported on the proximal end of the first jaw and extend across the longitudinal slot adjacent the first and second cam channels. The first cam follower extends through the first cam channel and the second cam follower extends through the second cam channel. Preferably, the tool assembly is pivotally attached to a body portion by an articulation joint. The body portion may form the distal end of a surgical stapling device or a proximal portion of a disposable loading unit. 
         [0012]    In another preferred embodiment, the tool assembly includes an anvil, a cartridge assembly housing a plurality of staples and a dynamic clamping member. The anvil and cartridge assembly are movable in relation to each other between spaced and approximated positions. The dynamic clamping member is movable in relation to the anvil and the cartridge assembly to eject the staples from the cartridge assembly. The tool assembly is pivotally attached to a body portion and is pivotable in relation to the body portion from a position aligned with the longitudinal axis of the body portion to a position oriented at an angle to the longitudinal axis of the body portion. An articulation and firing actuator extends at least partially through the body portion and the tool assembly. The articulation and firing actuator is operably associated with the dynamic clamping member and the tool assembly and is movable in relation thereto to selectively pivot the tool assembly in relation to the body portion and/or move the dynamic clamping member in relation to the tool assembly to eject the staples from the cartridge. 
         [0013]    Preferably, the articulation and firing actuator includes a flexible band having a first end portion extending at least partially through the body portion and through the cartridge assembly, a central portion extending from the first end portion operably associated with the dynamic clamping member and a second end portion extending from the central portion through the cartridge assembly and at least partially through the body portion to a position adjacent the first end. The articulation and firing actuator is operably associated with the tool assembly such movement of either the first end portion or the second end portion of the flexible band proximally and independently of the other end portion effects pivoting of the tool assembly in relation to the body portion, and movement of both the first and second end portions of the flexible band simultaneously effects movement of the dynamic clamping member to eject the staples from the cartridge assembly. In a preferred embodiment, an approximation member is operably associated with the tool assembly and is movable in relation to the tool assembly to move the anvil and cartridge assembly from the spaced to the approximated position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Various preferred embodiments of the presently disclosed tool assembly for use with a surgical stapling device are disclosed herein with reference to the drawings, wherein: 
           [0015]      FIG. 1  is a side perspective view of one preferred embodiment of the presently disclosed tool assembly in the approximated position; 
           [0016]      FIG. 2  is a side view of the tool assembly shown in  FIG. 1 ; 
           [0017]      FIG. 3  is a side, exploded perspective view of the tool assembly shown in  FIG. 1 ; 
           [0018]      FIG. 4A  is a schematic view of the jaws of the tool assembly shown in  FIG. 1  at a first stage of jaw approximation; 
           [0019]      FIG. 4B  is a schematic view of the jaws shown in  FIG. 4A  at a second stage of jaw approximation; 
           [0020]      FIG. 4C  is a schematic view of the jaws shown in  FIG. 4B  in an approximated position; 
           [0021]      FIG. 5  is a side perspective view of another preferred embodiment of the presently disclosed tool assembly in the approximated position; 
           [0022]      FIG. 6  is a side, exploded perspective view of the tool assembly shown in  FIG. 5 ; 
           [0023]      FIG. 7  is a side perspective view of the approximation member of the tool assembly shown in  FIG. 6 ; 
           [0024]      FIG. 8  is a side perspective view of the dynamic clamping member of the tool assembly shown in  FIG. 6 ; 
           [0025]      FIG. 9  is a top partial cross-sectional view with portions broken away looking through a portion of the cartridge assembly and showing the articulation and firing actuator of the tool assembly shown in  FIG. 6 ; and 
           [0026]      FIG. 10  is a cross-sectional view with portions removed and portions added, as would be seen along section lines  10 - 10  of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0027]    Preferred embodiments of the presently disclosed tool assembly for a stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. 
         [0028]      FIGS. 1-3  illustrate one preferred embodiment of the presently disclosed tool assembly shown generally as  10  for use with a surgical stapling device. Tool assembly  10  includes a pair of jaws including an anvil  12  and a cartridge assembly  14  and an approximation member  16 . Cartridge assembly  14  includes a support channel  18  for receiving a staple cartridge  14   a . Support channel  18  includes distal open channel portion  18   a  and a proximal portion  18   b  defining a truncated cylinder  18   c . Although not shown in detail, staple cartridge  14   a  houses a plurality of staples and can include conventional pushers (not shown) for translating movement of a staple drive assembly that typically includes a sled (e.g.,  131  in  FIG. 6 ) to movement of the staples through openings or slots in a tissue engaging surface  25  of cartridge  14   a.    
         [0029]    Anvil  12  has a tissue engaging surface  20  having a distal end  20   a  and a proximal end  20   b  and a proximal body portion  22 . A longitudinal slot  24  extends along the central longitudinal axis of anvil  12  through tissue engaging surface  20  and is dimensioned to slidably receive a portion of a drive assembly. The drive assembly typically includes a drive bar, a closure assembly, a sled, and a plurality of pushers. The drive assembly functions to eject staples from the cartridge and preferably also maintains a desired uniform tissue gap between the cartridge and the anvil during firing of the device. Proximal body portion  22  of anvil  12  is dimensioned to be generally pivotably received within truncated cylinder  18   c  of proximal portion  18   b  of support channel  18  such that tissue engaging surface  20  of anvil  12  is pivotable from a position spaced from tissue engaging surface  25  of cartridge  14   a  to an approximated position in juxtaposed alignment therewith. 
         [0030]    Tool assembly  10  includes an approximation member  16  having one or more cam channels  28  and  30 . Preferably, approximation member includes a pair of cam channels although a single cam channel having a pair of cam surfaces is envisioned. Approximation member  16  is dimensioned to be linearly slidable through proximal portion  18   b  of channel  18  and through a slot  22   a  formed in proximal body portion  22  of anvil  12 . A cam follower  32  extends through a bore  34  formed in proximal portion  22  of anvil  12  and through a hole  35  in proximal portion  18   b  of support channel  18  and is positioned within cam channel  28 . A cam follower  36  extends through a second bore  38  formed in the proximal portion  22  of anvil  12  and through a hole  39  in proximal portion and is positioned within cam channel  30 . When approximation member  16  is advanced through slot  22   a  in proximal portion  22  of anvil  12 , cam followers  32  and  36  move through cam channels  28  and  30 , respectively. Since approximation member  16  is confined to linear movement within slot  22   a , movement of approximation member  16  in a distal direction effects pivotal movement of anvil  12  from the open or spaced position to the closed or approximated position. The angles of the cam slots can be configured to provide a great variety of approximation motions to improve mechanical advantage and achieve specific results, e.g., grasping of tissue. 
         [0031]    Referring also to  FIGS. 4A-4C , cam channels  28  and  30  preferably are configured to pivot anvil  12  from an open position ( FIG. 4A ) towards cartridge assembly  14  in a controlled manner to initially facilitate grasping of tissue and thereafter provide for substantially parallel closure of the anvil and cartridge assembly. More specifically, cam channels  28  and  30  are preferably configured to position the distal end  20   a  of tissue contact surface  20  of anvil  12  substantially in contact with cartridge  14  ( FIG. 4B ) during the initial portion of an actuating stroke of approximation member  16 . This facilitates grasping of tissue even very thin tissue. During a second portion of the actuating stroke of approximation member  16 , distal end  20   a  of anvil  12  is moved away from cartridge assembly  14  to a resultant position in which tissue engaging surface  20  of anvil  12  is parallel or substantially parallel to tissue engaging surface  25  of cartridge assembly  14 . During the final portion of the actuating stroke of approximation member  16 , the anvil  12  and cartridge assembly  14  are brought together in parallel or substantially parallel closure to define a desired tissue gap ( FIG. 4C ). It is noted that any desired motion of anvil  12  can be achieved using the cam followers described herein. By moving anvil  12  in relation to cartridge assembly  14  from the spaced to the approximated position in the manner described above i.e., front or distal to back or proximal closure, the tendency for tissue to move forward within the jaws, as in conventional devices, is substantially eliminated. 
         [0032]    Although approximation member  16  is illustrated as being in the form of a plate with two distinct cam channels, differently configured approximation members are envisioned. For example, a single cam channel may be provided to engage two cam followers. Further, the cam channels need not be confined but rather can be formed on the surface of a plate, bar or the like. In such a device, the anvil may be urged by a biasing member to the closed or clamped position. 
         [0033]    Although one or more actuators has not been disclosed to advance the approximation member and/or fire staples from the cartridge assembly, it is envisioned that one or more of a variety of known pivotable, rotatable, or slidable actuators, e.g., trigger, knob, lever, etc., may be used to approximate the presently disclosed cartridge assembly and/or fire staples from the cartridge. It is also noted that the disclosed tool assembly may be or form the distal portion of a disposable loading unit or may be incorporated directly into the distal end of a surgical instrument, e.g., surgical stapler, and may include a replaceable cartridge assembly. 
         [0034]      FIGS. 5-10  disclose another preferred embodiment of the presently disclosed tool assembly shown generally as  100 . Tool assembly  100  includes an anvil  112  and a cartridge assembly  114 , an approximation member  116 , and an elongated body portion  120  including an articulation joint generally referred to as  122 . Elongated body portion  120  may form the proximal end of a disposable loading unit or the distal end of a surgical stapling device. Tool assembly  100  also includes a combined articulation and firing actuation mechanism  124  for articulating tool assembly  100  about articulation joint  122  and ejecting staples from cartridge assembly  114 . Although the articulation joint illustrated as a flexible corrugated member with preformed bend areas, articulation joint  122  may include any known type of joint providing articulation, e.g., pivot pin, ball and socket joint, a universal joint etc. 
         [0035]    Approximation member  116  is substantially similar to approximation member  16  and also includes cam channels  128  and  130  ( FIG. 7 ). Approximation member  116  further includes a pair of guide channels  126 . Guide channels  126  are dimensioned to receive guide pins  128  which extend through elongated body portion  120  and function to maintain approximation member  116  along a linear path of travel. Approximation member  116  is constructed from a flexible material, e.g., spring steel, which is capable of bending around articulation joint  122 . Alternately, it is envisioned that approximation member  116  may include a resilient rod, band or the like with cam surfaces formed thereon. Approximation member  116  operates in substantially the same manner as approximation member  16  and will not be discussed in further detail herein. 
         [0036]    Cartridge assembly  114  includes a support channel  118 , a sled  131  and a dynamic clamping member  132  which, preferably, includes an upper flange  134   a  for slidably engaging a bearing surface of the anvil and lower flange  134   b  for slidably engaging a bearing surface of the cartridge. A knife blade  134  is preferably supported on a central portion  134   c  of dynamic clamping member  132  to incise tissue. Knife blade may be secured to dynamic clamping member  132  in a removable or fixed fashion, formed integrally with, or ground directly into dynamic clamping member  132 . Sled  131  is slidably positioned to translate through cartridge  114  in a known manner to eject staples from the cartridge. Sled  131  or the like can be integral or monolithic with dynamic clamping member  132 . Sled  131  is positioned distal of and is engaged and pushed by dynamic clamping member  132 . The position of  131  is to effect firing or ejection of the staples to fasten tissue prior to cutting the stapled tissue. Flange  134   b  preferably is positioned within a recess  138  formed in the base of cartridge  114 . Flange  134   a  is preferably positioned within a single or separate recess formed in anvil  112 . Again, flanges  134   a  and  134   b  need not be positioned in a recess but can slidably engage a respective surface of the anvil and cartridge. Dynamic clamping member  132  preferably is positioned proximal of sled  130  within cartridge assembly  114 . Dynamic clamping member  132  functions to provide, restore and/or maintain the desired tissue gap in the area of tool assembly  100  adjacent sled  130  during firing of staples. 
         [0037]    It is preferred that the anvil and preferably the dynamic clamping member be formed of a material and be of such a thickness to minimize deflection of the anvil and dynamic clamping member during firing of the device. Such materials include surgical grade stainless steel. The anvil is preferably formed as a solid unit. Alternatively, the anvil may be formed of an assembly of parts with conventional components. 
         [0038]    Referring to  FIGS. 6 ,  9  and  10 , articulation and firing mechanism  124  includes a tension member  140  which can have loops  124  or other connection portions or connectors for connection to suitable connection members of one or more actuators or of an actuation mechanism. Although illustrated as a flexible band, tension member  140  may be or include one or more of any flexible drive member having the requisite strength requirements and being capable of performing the functions described below, e.g., a braided or woven strap or cable, a polymeric material, a para-aramid such as Kevlar™, etc. Kevlar™ is a trade designation of poly-phenyleneterephthalamide commercially available from DuPont. A pair of suitable fixed or rotatable members, preferably rollers  142   a  and  142   b , are secured at the distal end of cartridge assembly  114 . Rollers  142   a  and  142   b  may be formed or supported in a removable cap  114   b  ( FIG. 6 ) of cartridge assembly  114 . Alternately, cap  114   b  may be formed integrally with staple cartridge  114   a  or cartridge channel  118 . Rollers  142   a  and  142   b  can also be secured to or formed from cartridge support channel  118 . Tension member  140  extends distally from elongated body  120  of tool assembly  100 , distally through a peripheral channel  142  in staple cartridge  114   a , around roller  142   a , proximally, preferably, alongside central longitudinal slot  144  formed in cartridge  114   a , through a slot  200 , preferably a transverse slot, in or around a proximal portion of dynamic clamping member  132 , distally around roller  142   b , and again proximally through a channel  146  formed in cartridge  114   a  to a proximal portion of elongated body  120 . Alternately, two tension members can be employed, each of which may be secured to dynamic clamping member  132 . As illustrated in  FIG. 10 , channels  142  and  146  can be at least partly defined by an inner and/or outer wall of cartridge  114   a  and/or by cartridge support channel  118 . Unlike as shown, channels  142  and  146  should be in a consistent, i.e., same, functionally same or corresponding location on both sides of the staple cartridge. Thus, it is envisioned that there would be two peripheral channels  142 , or two channels  146 . 
         [0039]    In use, when a first end or portion  150  of tension member  140  is retracted by suitable means in the direction indicated by arrow “A”, as viewed in  FIG. 9 , tool assembly  100  will articulate about pivot member  122   a  in the direction indicated by arrow “D”. When second end or portion  152  of tension member  140  is retracted in the direction indicated by arrow “B”, tool assembly  100  will articulate in the direction indicated by arrow “C”. When both ends of tension member  140  are retracted simultaneously, tension member  140  will advance dynamic clamping member  132  distally through slot  144  in cartridge  114   a  to advance dynamic clamping member  132  and sled  130  through cartridge  114   a  and by engaging pushers, eject staples from the cartridge and incise tissue in the tissue gap. In order to prevent dynamic clamping member  132  from advancing through slot  144  when the tool assembly is being articulated, i.e., when only one end of tension member  140  is retracted, a lockout device (not shown), e.g., a shear pin, may be provided to prevent movement of the dynamic clamping member or delay it until a predetermined force has been applied to the dynamic clamping member. It is envisioned that multiple tension members, e.g., bands, can be employed, respectively, to perform individual or a combination of functions. For example, a pair of tension members can be employed, one to articulate, and the other to approximate, clamp and fire. The tension members can be fixed to the dynamic clamping member or a knife carrying member or to a combination dynamic clamping member, knife member and/or sled member. 
         [0040]    The above-described tool assembly may be incorporated into a disposable loading unit such as disclosed in U.S. Pat. No. 6,330,965 or attached directly to the distal end of any known surgical stapling device. Although a handle assembly for actuating the approximation member and the combined articulation and firing mechanism have not been specifically disclosed herein, it is to be understood that the use of a broad variety of different actuating mechanisms and handle configurations are envisioned including toggles, rotatable and slidable knobs, pivotable levers or triggers, pistol grips, in-line handles, remotely operated systems and any combination thereof. The use of an above-described tool assembly as part of a robotic system is envisioned. 
         [0041]    It will be understood that various modifications may be made to the embodiments disclosed herein. For example, although this application focuses primarily on the use of surgical staples, other fastening devices, such as two-part fasteners, may be included in this device. In a device in which two-part fasteners are used, each of the anvil staple forming pockets may be configured to receive one part of the two-part fastener. Further, it is envisioned that the teachings provided in this disclosure may be incorporated into surgical devices other than stapling devices including graspers. 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.