Abstract:
An end effector for stapling and cutting tissue comprising a shaft portion extending along a longitudinal axis, a first jaw, and a second jaw is disclosed. One of the first jaw and the second jaw comprises a plurality of staple cavities arranged in a plurality of curved staple cavity rows, wherein the second jaw is moveable relative to the first jaw between an open orientation and a closed orientation. The second jaw is configured to tilt laterally about the longitudinal axis between the open orientation and the closed orientation. The second jaw comprises an intermediate portion and a distal portion, wherein the distal portion is structured to clamp tissue against the first jaw before the intermediate portion when the second jaw moves from the open orientation toward the closed orientation.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a continuation application under 35 U.S.C. §120 of U.S. patent application Ser. No. 11/652,165, filed on Jan. 11, 2007, entitled SURGICAL STAPLING DEVICE WITH A CURVED END EFFECTOR, now U.S. Pat. No. 8,540,128, the entire disclosure of which is hereby incorporated by reference herein. 
     The subject application is related to six co-pending and commonly-owned applications filed on Jan. 11, 2007, the disclosure of each is hereby incorporated by reference in their entirety, these six applications being respectively entitled: 
     (1) U.S. patent application Ser. No. 11/652,169, entitled Surgical Stapling Device With a Curved Cutting Member, now U.S. Patent Application Publication No. 2008/0169332; 
     (2) U.S. patent application Ser. No. 11/652,166, entitled Surgical Stapling Device Having Supports for a Flexible Drive Mechanism, now U.S. Pat. No. 8,827,133; 
     (3) U.S. patent application Ser. No. 11/652,188, entitled Apparatus for Closing a Curved Anvil of a Surgical Stapling Device, now U.S. Pat. No. 7,434,717; 
     (4) U.S. patent application Ser. No. 11/652,164, entitled Curved End Effector for a Surgical Stapling Device, now U.S. Pat. No. 8,701,958; 
     (5) U.S. patent application Ser. No. 11/652,423, entitled Buttress Material For Use With a Surgical Stapler, now U.S. Patent Application Publication No. 2008/0169328; and 
     (6) U.S. patent application Ser. No. 11/652,170, entitled Surgical Stapler End Effector With Tapered Distal End, now U.S. Patent Application Publication No. 2008/0169333. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention generally relates to surgical staplers, and, more particularly, to surgical staplers having a curved end-effector and to surgical techniques for using the same. 
     2. Description of the Related Art 
     As known in the art, surgical staplers are often used to deploy staples into soft tissue to reduce or eliminate bleeding from the soft tissue, especially as the tissue is being transected, for example. Surgical staplers, such as an endocutter, for example, often comprise an end-effector which is configured to secure the soft tissue between first and second jaw members. The first jaw member often includes a staple cartridge which is configured to removably store staples therein and the second jaw member often includes an anvil. In use, the staples are typically deployed from the staple cartridge by a driver which traverses a channel in the staple cartridge. The driver causes the staples to be deformed against the anvil and secure layers of the soft tissue together. Often, as known in the art, the staples are deployed in several staple lines, or rows, in order to more reliably secure the layers of tissue together. The end-effector may also include a cutting member, such as a knife, for example, which is advanced between two rows of the staples to resect the soft tissue after the layers of the soft tissue have been stapled together. 
     The end-effectors of previous endocutters are often configured to deploy staples in straight lines. During many surgical techniques, such as the resection of stomach tissue, for example, such a linear deployment is often preferred. During these techniques, the end-effector is typically inserted through a cannula to access the surgical site and, as a result, it is often desirable for the end-effector to have a linear configuration that can be aligned with an axis of the cannula before the end-effector is inserted therethrough. However, in some circumstances, end-effectors having such a linear configuration are somewhat difficult to use. More particularly, for example, when the end-effector must be placed adjacent to or against a cavity wall, such as the thoracic cavity wall, for example, it is often difficult for the surgeon to position a jaw of the end effector behind delicate or fragile tissue which is proximal to and/or attached to the cavity wall. Furthermore, even if the surgeon is successful in positioning a jaw behind the tissue, owing to the linear configuration of the end-effector, the surgeon may not be able to see the distal end of the end-effector. 
     In some circumstances, endocutters having a curved end-effector have been used for accessing, stapling and transecting tissue. These end-effectors typically include curved anvils and staple cartridges which co-operate to deploy the staples in curved rows. To deploy the staples in this manner, the staple driver and the cutting member can be moved through a curved path by a flexible drive member. However, owing to the amount of force that is typically transmitted through the flexible drive member, the drive member may buckle or otherwise deform in an unsuitable manner. Furthermore, previous curved end-effectors are configured such that the distal ends of the jaw members are the last portions of the jaw members to contact the soft tissue. As a result, tissue may escape from between the jaw members before the jaw members are completely closed. What is needed is an improvement over the foregoing. 
     SUMMARY 
     In various embodiments, an end effector for use with a surgical instrument comprises a shaft portion extending along a longitudinal axis, a first jaw, and a second jaw. The first jaw comprises a first intermediate portion and a first distal portion, wherein one of the first jaw and the second jaw comprises a plurality of staple cavities arranged in a plurality of curved staple cavity rows, wherein the second jaw is moveable relative to the first jaw between an open orientation, a partially-closed orientation, and a closed orientation. The second jaw is configured to tilt laterally about the longitudinal axis. The second jaw comprises a second intermediate portion, wherein the second intermediate portion is brought into facing opposition with the first intermediate portion when the second jaw is moved to the closed orientation from the partially-closed orientation, and wherein the second intermediate portion is positioned a range of partially-closed intermediate distances from the first intermediate portion when the second jaw is in the partially-closed orientation. The second jaw further comprises a second distal portion, wherein the second distal portion is positioned a partially-closed distal distance from the first distal portion when the second jaw is in the partially-closed orientation, and wherein the partially-closed distal distance is less than the distances in the range of partially-closed intermediate distances. 
     In various embodiments, an end effector for stapling and cutting tissue comprises a shaft portion extending along a longitudinal axis, a first jaw, and a second jaw. One of the first jaw and the second jaw comprises a plurality of staple cavities arranged in a plurality of curved staple cavity rows, wherein the second jaw is moveable relative to the first jaw between an open orientation and a closed orientation. The second jaw is configured to tilt laterally about the longitudinal axis between the open orientation and the closed orientation. The second jaw comprises an intermediate portion and a distal portion, wherein the distal portion is structured to clamp tissue against the first jaw before the intermediate portion when the second jaw moves from the open orientation toward the closed orientation. 
     In various embodiments, an end effector for use with a surgical instrument comprises a shaft portion extending along a longitudinal axis, a first jaw, and a second jaw. The first jaw comprises a first proximal portion and a first distal portion comprising a pivot surface. One of the first jaw and the second jaw comprises a plurality of staple cavities arranged in a plurality of curved staple cavity rows. The second jaw comprises a second proximal portion and a second distal portion. The end effector further comprises a hinge connecting the first proximal portion and the second proximal portion, wherein the second jaw is moveable between an open orientation, a partially-closed orientation, and a closed orientation. The second jaw is configured to tilt laterally about the longitudinal axis at the hinge, wherein the second jaw is structured to pivot relative to the pivot surface of the first distal portion when the second jaw moves between the partially-closed orientation and the closed orientation. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a schematic of an endocutter being used to transect and staple tissue; 
         FIG. 2  is a partial cut-away view of the endocutter of  FIG. 1 ; 
         FIG. 3  is a partial cross-sectional view of the endocutter of  FIG. 2  taken along line  3 - 3  in  FIG. 2 ; 
         FIG. 4  is a perspective cut-away view of the endocutter of  FIG. 2 ; 
         FIG. 5  is a bottom view of the anvil of the endocutter of  FIG. 2 ; 
         FIG. 6  is a schematic view of staples being deployed from the staple cartridge of the endocutter of  FIG. 2  by a staple driver; 
         FIG. 7  is a schematic view of staples being deployed from the staple cartridge of  FIG. 2  where the staple driver has been advanced within the staple cartridge with respect to its position in  FIG. 6 ; 
         FIG. 8  is a perspective view of the cutting member and drive bar of the endocutter of  FIG. 2 ; 
         FIG. 9  is a schematic of an opened thoracic cavity; 
         FIG. 10  is a schematic of an endocutter having a curved end-effector in accordance with an embodiment of the present invention being positioned against the side wall of a thoracic cavity; 
         FIG. 11  is a perspective view of the endocutter of  FIG. 10  illustrated in a closed configuration and positioned about a pulmonary artery; 
         FIG. 12  is a perspective view of the end-effector of the endocutter of  FIG. 11 ; 
         FIG. 13  is a top view of the staple cartridge of the end-effector of  FIG. 12 ; 
         FIG. 14  is a bottom view of the jaw configured to support the staple cartridge of  FIG. 13 ; 
         FIG. 15  is a perspective view of the cutting member and staple driver of the endocutter of  FIG. 2 ; 
         FIG. 16  is a top view of the cutting member and staple driver of  FIG. 15 ; 
         FIG. 17  is a top view of a cutting member and staple driver in accordance with an embodiment of the present invention; 
         FIG. 18  is a perspective view of an endocutter having a curved end-effector in accordance with an alternative embodiment of the present invention; 
         FIG. 19  is a top view of the staple cartridge of the end-effector of  FIG. 18 ; 
         FIG. 20  is a perspective view of an endocutter having a curved end-effector in accordance with an alternative embodiment of the present invention; 
         FIG. 21  is a top view of the staple cartridge of the end-effector of  FIG. 20 ; 
         FIG. 22  is a perspective view of an endocutter having a curved end-effector in accordance with an alternative embodiment of the present invention; 
         FIG. 23  is a top view of the staple cartridge of the end-effector of  FIG. 22 ; 
         FIG. 24  is a cross-sectional view of the end-effector of  FIG. 12  taken along line  24 - 24  in  FIG. 12 ; 
         FIG. 25  is a cross-sectional view of the end-effector of  FIG. 12  after the drive bar has been advanced into the end-effector; 
         FIG. 26  is a schematic of the cutting member and drive bar of the endocutter of  FIGS. 24 and 25 ; 
         FIG. 27  is a perspective view of an endocutter having a curved end-effector configured to close in an asymmetric manner in accordance with an embodiment of the present invention; 
         FIG. 28  is a cross-sectional view of the hinge connection between the jaws of the curved end-effector of  FIG. 27  wherein the jaws are in an open configuration; 
         FIG. 29  is a cross-sectional view of the hinge connection of  FIG. 28  wherein the jaws are in a partially closed configuration; 
         FIG. 30  is an end view of the curved end-effector of  FIG. 27  illustrated in a partially closed configuration; 
         FIG. 31  is a cross-sectional view of the hinge connection of  FIG. 28  wherein the end-effector is in a closed configuration; 
         FIG. 32  is an end view of the curved end-effector of  FIG. 27  illustrated in a closed configuration; 
         FIG. 33  is a detail view of a first slot of the hinge connection of  FIG. 28  that is configured to receive a first projection extending from the anvil and is also configured to define a first path for relative movement therebetween; 
         FIG. 34  is a detail view of a second slot of the hinge connection of  FIG. 28  that is configured to receive a second projection extending from the anvil and is also configured to define a path for relative movement therebetween that is different than the first path; 
         FIG. 35  is a perspective view of an endocutter having a curved end-effector in accordance with an alternative embodiment of the present invention; 
         FIG. 36  is a side view of the endocutter of  FIG. 35 ; 
         FIG. 37  is a schematic of the endocutter of  FIG. 35  being used to transect a pulmonary artery; 
         FIG. 38  is a perspective view of an endocutter having a curved end-effector in accordance with an alternative embodiment of the present invention; 
         FIG. 39  is a perspective view of the staple cartridge of the end-effector of  FIG. 38 ; 
         FIG. 40  is a side view of the end-effector of the endocutter of  FIG. 39 ; 
         FIG. 41  is a partial cross-sectional view of the end-effector of the endocutter of  FIG. 38 ; 
         FIG. 42  is a perspective view of the staple driver, cutting member and drive bar of  FIG. 41 ; 
         FIG. 43  is a perspective view of the cutting member and drive bar of  FIG. 41 ; 
         FIG. 44  is a perspective view of an endocutter having a curved staple cartridge and a curved anvil configured to retain buttress material thereon in accordance with an embodiment of the present invention; 
         FIG. 45  is a top view of the staple cartridge of  FIG. 44  illustrating a piece of buttress material positioned thereon; 
         FIG. 46  is a bottom view of the anvil of  FIG. 44  illustrating two pieces of buttress material positioned thereon; 
         FIG. 47  is a cross-sectional view of the end-effector of the endocutter of  FIG. 44  taken along line  47 - 47  in  FIG. 44 ; 
         FIG. 48  is a perspective view of an endocutter in accordance with an embodiment of the present invention; 
         FIG. 49  is a cross-sectional view of the end effector of  FIG. 48  taken along line  49 - 49  in  FIG. 48 ; and 
         FIG. 50  is an enlarged cross-sectional view of the distal end of the end effector of  FIG. 49 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate preferred embodiments of the invention, in various forms, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     As known in the art, it is often necessary to resect tissue from a patient after the tissue has become necrotic or cancerous, for example. Frequently, blood vessels within the tissue are transected as the tissue is being cut. As a result, blood may flow from the blood vessels and complicate the surgery or endanger the patient. Often, a surgical stapler is used to secure and compress several layers of tissue together in order to substantially close the blood vessels. For example, referring to  FIG. 1 , a surgical stapler, such as an endocutter, can include devices which staple and then cut the tissue. As a result, the blood vessels can be substantially closed by the staples before the tissue is cut, thereby reducing bleeding therefrom. 
     Referring to  FIGS. 1 and 2 , endocutters, such as endocutter  100 , for example, typically include an end-effector  102 , a handle portion  104  ( FIG. 2 ), and a shaft  106  extending therebetween. End-effector  102  includes first jaw  108  and second jaw  110  which can be configured in one of an open or a closed configuration. In their open configuration, jaws  108  and  110  can be configured to receive soft tissue therebetween, for example, allowing jaws  108  and  110  to be placed on opposite sides thereof. To close the jaws and secure the tissue therebetween, at least one of the jaws is moved against the tissue such that it holds the tissue against the opposing jaw. In the illustrated embodiment, jaw  108  is moved relative to jaw  110 . Once closed, as known in the art, an anti-firing mechanism can be released allowing cutting member  120  to be advanced toward the tissue. Thereafter, as described in greater detail below, staples  132  can be deployed from staple cartridge  112  in jaw  110  to secure the layers of tissue together. Such mechanisms are described in greater detail in U.S. Pat. No. 7,000,818, the disclosure of which is hereby incorporated by reference herein. 
     Referring to  FIGS. 3-4 and 6-8 , cutting member  120  includes body  122  and cutting surface  124 . Cutting member  120  is operably engaged with firing trigger  128  of handle portion  104  via drive bar  126  wherein the actuation of firing trigger  128  advances drive bar  126  and cutting member  120  toward the distal ends of jaws  108  and  110 . In various embodiments, firing trigger  128  can activate a firing drive system which may be manually, electrically, or pneumatically driven. Cutting member body  122  further includes distal portion  123  which is configured to engage a staple driver  130  commonly supported within staple cartridge  112  and advance staple driver  130  therein. As staple driver  130  is advanced, staples  132  are lifted by driver  130  toward anvil  134 . Referring to  FIG. 5 , anvil  134  includes pockets  136  which are configured to deform the legs of staples  132  and capture the layers of tissue therein in a known manner. In the present embodiment, as staple driver  130  is advanced, cutting member  120  is also advanced to resect the tissue after it has been stapled. In other embodiments, cutting member  120  can be configured to resect the tissue during or before the tissue has been stapled. 
     Referring to  FIGS. 1-7 , the end-effector of many typical endocutters is linear, i.e., it is configured to deploy staples in straight lines. In these endocutters, drive bar  126  is configured to move cutting member  120  in a straight line and, accordingly, drive bar  126  is rigid such that it does not substantially deflect when the force to deploy the staples and transect the tissue is transmitted therethrough. In addition to the above, a variety of other drive arrangements are known for deploying staples in straight lines while resecting the tissue located between opposite lines of staples. However, it is often difficult to position such linear end-effectors in a surgical site. During at least one surgical technique, referring to  FIGS. 9 and 10 , an endocutter is used to transect and staple a pulmonary artery (PA) during a partial or total pneumonectomy. During this technique, the end-effector is typically placed against the wall of the thoracic cavity (TCW) such that jaw  110 , and staple cartridge  112 , are positioned behind the pulmonary artery. However, as the wall of the thoracic cavity is typically curved, it is often difficult to position linear jaw  110  behind the pulmonary artery. Furthermore, even if the surgeon is successful in positioning a jaw behind the pulmonary artery, the surgeon, owing to the linear configuration of the end-effector, cannot readily see the end of the jaw as it is typically hidden behind the pulmonary artery. As a result, it is difficult for the surgeon to readily determine whether the end of the jaw extends beyond the pulmonary artery, i.e., whether the pulmonary artery is entirely captured between the jaws of the end-effector. 
     In various embodiments of the present invention, referring to  FIG. 10 , the end-effector of the endocutter is curved. A curved end-effector allows a surgeon to more easily position the end-effector against the curved wall of the thoracic cavity, for example. In at least one embodiment, the curvature of the end-effector can be configured to substantially match the contour of a typical thoracic cavity wall. In these embodiments, the curvature of several thoracic cavity walls can be measured and statistically analyzed to determine the optimum profile of the curved end-effector. This profile can include several arcuate portions and, in addition, several linear portions. In other embodiments, referring to endocutter  200  of  FIGS. 10-14 , the curvature of the thoracic cavity wall can be approximated by a single radius of curvature. Such embodiments can be simpler and less expensive to manufacture. In at least one embodiment, this radius of curvature is 1.2″. In other various embodiments, the curvature of the end-effector can be configured to match the profile of the lower rectum, pelvis, or lower abdomen. 
     In order to transect the pulmonary artery PA, as mentioned above, a surgeon typically positions one of jaws  208  and  210  behind the pulmonary artery PA against the thoracic cavity wall TCW. Once positioned, referring to  FIGS. 10 and 11 , closure trigger  117  is actuated to pivot jaw  208  with respect to jaw  210  such that anvil  234  contacts the pulmonary artery and compresses the pulmonary artery between anvil  234  and staple cartridge  212 . Unlike previous linear end-effectors, the curved profile of end-effector  202  assists the surgeon in locating the distal end of the end-effector with respect to the pulmonary artery. More particularly, referring to  FIGS. 13 and 14 , end  240  of jaw  210  can extend to one side of a centerline, or axis  242 , defined by the distal end of shaft  106 . As a result of this offset, the surgeon may be able to more readily see distal end  240  and evaluate whether the pulmonary artery is completely captured within the end-effector, for example. 
     Once the jaws of the endocutter have been closed, the cutting member of the endocutter can be advanced toward the tissue, as described above. In previous endocutters, referring to  FIGS. 4, 15 and 16 , cutting member  120  is configured to travel within linear slots defined by staple cartridge  112 , staple cartridge channel  138 , and anvil  134 . Similarly, staple driver  130  is configured to travel within at least one linear slot defined by staple cartridge  112 . As a result of these linear slots, cutting member  120  and staple driver  130  are moved in a straight line between the proximal and distal ends of the end-effector. For example, referring to  FIG. 4 , cutting member  120  includes first projections  146  extending from body  122  which are sized and configured to fit within slot  148  of anvil  134 . Cutting member  120  further includes second projections  150  extending from body  122  which are sized and configured to retain cutting member body  122  within slot  164  of staple cartridge  112  and slot  152  of jaw  110 . Accordingly, as cutting member  120  is advanced from the proximal end of the end-effector to the distal end, linear slots  148 ,  152  and  164  define a linear path for cutting member  120 . 
     In various embodiments of the present invention, referring to  FIGS. 13 and 14 , staple cartridge  212 , staple cartridge channel  238  and anvil  234  can include curved slots for controlling the movement of cutting member  120  and staple driver  130  along a curved path. These curved slots can include several arcuate portions and several linear portions. In various embodiments, the curved slots can be defined by one radius of curvature. In the embodiment illustrated in  FIGS. 13 and 14 , staple cartridge  212  and staple cartridge channel  238  can include curved slots  264  and  252 , respectively. Similar to the above, curved slots  264  and  252  can be configured to receive a portion of cutting member  120  and guide cutting member  120  along a path defined by slots  264  and  252 . However, owing to the substantially linear configuration of cutting member  120 , cutting member  120  may, in some circumstances, become misaligned or stuck within curved slots  264  and  252 , or a corresponding curved slot in anvil  234 . 
     To ameliorate the above-described problem, at least a portion of the cutting member and staple driver can be curved. In at least one embodiment, the cutting member and staple driver can be configured to substantially match the curvature of the path defined by curved slots  264  and  252 , i.e., path  258 . More particularly, referring to  FIGS. 13 and 17 , cutting member body  222  can include a center portion which is configured to match the radius of curvature of path  258 , and a curved inner portion  260  and a curved outer portion  262  which are configured to co-operate with the sidewalls of curved slots  264  and  252 . For example, curved cartridge channel slot  252  can include inner surface  254  and outer surface  256  and curved staple cartridge slot  264  can include inner surface  266  and outer surface  268  where, in the present embodiment, inner surfaces  254  and  266  are substantially defined by radius of curvature D, which is smaller than the radius of curvature of path  258 , and outer surfaces  256  and  268  are substantially defined by radius of curvature C, which is larger than the radius of curvature of path  258 . As illustrated in  FIG. 17 , inner portion  260  of cutting member  220  can be configured to closely parallel the profile of inner surfaces  254  and  266 , and outer portion  262  of cutting member  220  can be configured to closely parallel the profile of outer surfaces  256  and  268 . Furthermore, although not illustrated, anvil  234  can include a curved slot which, similar to slots  264  and  252 , co-operates with curved cutting member  220  to guide cutting member along path  258 . As a result of the above, the likelihood of cutting member  220  becoming misaligned or stuck within curved path  252  can be reduced. 
     Alternatively, although not illustrated, the cutting member can include slots which are configured to co-operate with features on the anvil and/or staple cartridge and guide the cutting member along a curved path. More particularly, the anvil and/or staple cartridge can each include an elongate, arcuate projection, or a plurality of projections, which define a curved, or curvilinear, path for the cutting member. The slots of the cutting member can be configured to receive the projections and guide the cutting member along the curved path. In one embodiment, one of the anvil and staple cartridge can include such a projection, or a plurality of projections, and the other of the anvil and staple cartridge can include a slot configured to receive a portion of the cutting member, as described above. 
     Similar to the above, at least a portion of staple driver  230  can be configured to substantially match the curvature of path  258 . More particularly, referring to  FIG. 17 , staple driver  230  can include a center arcuate portion  270  which is configured to match the radius of curvature of path  258 , and an inner arcuate portion  272  and an outer arcuate portion  274  which are configured to co-operate with the sidewalls of slots, or channels, within staple cartridge  212 . Similar to staple driver  130 , staple driver  230  can include ramps which are configured to lift, or deploy, staples  132  against anvil  234  positioned opposite staple cartridge  212 . However, in the present embodiment, ramps  276  of staple driver  230  can be curved to deploy staples  132  along a curved staple line. More particularly, for example, the ramps can be defined by a radius of curvature which substantially matches the radius of curvature of a staple line. For example, ramp  278  is defined by a radius of curvature which substantially matches the radius of curvature of staple line  280 , i.e., radius of curvature A. 
     Although the path of the cutting member has been described above as being defined by a single radius of curvature, the invention is not so limited. In various embodiments, referring to  FIGS. 13 and 14 , end-effector  202  of endocutter  200  can include curved portion  263  and, in addition, linear portion  261  which is substantially collinear with an axis defined by the distal portion of shaft  116 , i.e., axis  242 . In at least one embodiment, curved portion  263  can further include first portion  265  and second portion  267 . Referring to  FIG. 13 , first portion  265  can include a proximal end connected to linear portion  261  positioned along axis  242  and a distal end spaced from axis  242  wherein second portion  267  can include a proximal end connected to the distal end of first portion  265  and extend toward axis  242 . Stated another way, first portion  265  can define an arcuate portion which extends away from axis  242  and second portion  267  can define an arcuate portion which extends toward axis  242 . As described above, an end-effector having such a profile may facilitate the positioning of the end-effector against the wall of the thoracic cavity, for example. 
     Referring to  FIGS. 18-21 , the end-effector of other various embodiments of the present invention can include other advantageous profiles. For example, referring to  FIGS. 18  and  19 , end-effector  302  can include linear portion  361  and curved portion  363  wherein the distal end of slot  364  can be positioned along axis  242 . As a result, although the cutting member progresses along an arcuate path offset with respect to axis  242 , the cutting member will stop at a point along axis  242 . Thus, as long as the surgeon is able to discern the orientation of axis  242 , the surgeon will know that the cutting member will not progress beyond axis  242  and can thereby gauge the point at which the tissue will no longer be transected. In another embodiment, referring to  FIGS. 20 and 21 , end-effector  402  can include linear portion  461  and curved portion  463  wherein distal tip  440  of the end-effector lies along axis  242  although at least a portion of the end-effector is offset with respect to axis  242 . In this embodiment, as long as the surgeon is able to discern the orientation of axis  242 , the surgeon can gauge the location of the distal end of the end-effector when moving or dissecting tissue. 
     In other various embodiments, referring to  FIGS. 22 and 23 , the end-effector can define a slot  564  and an arcuate path for the cutting member that is defined by an angle that is greater than or equal to 90 degrees. More particularly, for example, path  558  can include linear portion  561  and curved portion  563  wherein curved portion  563  is defined by a radius of curvature that spans an arc corresponding to an approximately 110 degree angle. As a result of the significant curvature of curved portion  563 , a surgeon can position a pulmonary artery, for example, entirely within curved portion  563 . In various embodiments, referring to  FIG. 26 , staples  132  may only be positioned within cavities in curved portion  563 , and not linear portion  561 . In these embodiments, the staple lines can be comprised of continuous, curved rows without abrupt changes in direction within the staple line. As known in the art, abrupt changes in a staple line may provide a leak path for blood to flow therethrough. As a result of the above embodiments, the likelihood of such a leak path is reduced. 
     As described above, the anvil and staple cartridge can include curved slots for receiving and guiding the cutting member. In many embodiments, the anvil and the staple cartridge can be configured such that their features parallel the curved slots therein. For example, referring to  FIGS. 13 and 14 , curved portion  263  of staple cartridge  212  can include an inner radius of curvature and an outer radius of curvature which parallel the radius of curvature of curved slot  264 . More particularly, referring to  FIG. 13 , the inner surface of staple cartridge  212  can be defined by radius of curvature E and the outer surface of staple cartridge  212  can be defined by radius of curvature B, wherein curvatures B and E share a substantially common radial point with radius of curvatures C and D which, as described above, substantially define the inner and outer surfaces of slot  264 . However, in various embodiments, although not illustrated, the inner and outer surfaces of the anvil and/or staple cartridge, or any other features thereof, may be non-parallel to the curved slot. In these embodiments, the anvil and staple cartridge, and the jaws surrounding them, may be configured to achieve any suitable configuration or purpose. 
     In previous endocutters, as described above and referring to  FIGS. 4 and 8 , linear drive bar  126  is configured to advance cutting member  120  along a linear path and, as a result, drive bar  126  is constructed such that is rigid and does not substantially deflect. After cutting member  120  has been advanced into slots  148 ,  164  and  152  of anvil  134 , staple cartridge  112 , and staple cartridge channel  138 , respectively, at least a portion of drive bar  126  can enter into slots  148 ,  164  and  152 . However, although cutting member  120  is guided and supported within slots  148 ,  164 , and  152 , drive bar  126 , in these previous devices, is unsupported within slots  148 ,  164 , and  152 . As a result, drive bar  126  may deflect or buckle in an uncontrollable and undesirable manner when load is transmitted therethrough. 
     In various embodiments of the present invention, a flexible drive bar can be used to advance the cutting member within the end-effector. More particularly, in order for the drive bar to be advanced into and translate within the curved slots of the end-effector, the drive bar can deflect to closely parallel the curvature of the curved slots of the end-effector. In various embodiments, unlike previous endocutters, the slots within the anvil and staple cartridge can be configured to support the flexible driver bar. More particularly, after cutting member  120  has been at least partially advanced within slots  248 ,  264 , and  252 , referring to  FIG. 25 , at least a portion of drive bar  226  can enter slots  248 ,  264 , and  252 . Slot  248  can include support surfaces  249  which are configured to abut, or be positioned closely adjacent to, side surfaces  227  of drive bar  226 . Similarly, surfaces  254  and  256  of slot  252  and surfaces  266  and  268  of slot  264  can also support the drive bar. While these features are particularly advantageous when used with curved end-effectors, they can also be used in linear end-effectors. In these embodiments, even though the slots may be linear, the slots can support the driver, whether rigid or flexible, and prevent it from buckling in the event that it is overloaded, for example. 
     Although flexible drive bar  226  can be used to advance linear cutting member  120  and linear staple driver  130  within a curved end-effector, as described above, flexible drive bar  226  can also be used to advance curved cutting members and staple drivers, such as cutting member  220  and staple driver  230 , for example, within a curved end-effector. Furthermore, although not illustrated, one of the anvil and staple cartridge can include a slot configured to receive and guide the cutting member and the other of the anvil and staple cartridge can include a slot configured to receive and support the drive bar. In these embodiments, the slot which is configured to receive the cutting member can have a different geometry than the slot which is configured to receive the drive bar. Accordingly, the cutting member and the drive bar can have different thicknesses, for example. 
     In various embodiments, the support surfaces of slots  248 ,  264  and  252  may be continuous, i.e., they may be configured to contact drive bar  226  continuously along the length thereof, or, alternatively, slots  248 ,  264  and  252  may be configured to contact drive bar  226  at various, spaced-apart locations. In these embodiments, projections may extend from the slot walls to define the path of the cutting member and the drive bar. In various embodiments, drive bar  226  may be comprised of a flexible, unitary material such as plastic, for example. Alternatively, referring to  FIGS. 25 and 26 , drive bar  226  may be comprised of a laminated material, i.e., a material comprised of two or more materials bonded together. In these embodiments, two or more strips of material may be glued together where the strips have the same cross-sectional geometry, or, alternatively, different cross-sectional geometries. Furthermore, the strips may be comprised of the same material or different materials. The cross-sectional geometries and materials of the above-described embodiments may be selected such that the drive bar is more flexible when deflected in one direction and less flexible when deflected in a different direction. 
     As described above, the curvature of an end-effector can be selected such that it facilitates the placement of the end-effector in a particular surgical site. In various embodiments, referring to  FIGS. 35-37 and 38-40 , the end-effector can be curved in a downward or upward direction, i.e., it can be curved in a plane that is substantially parallel to planes defined by the staple lines. More particularly, referring to  FIGS. 38 and 39 , staple cavities  803 , which are configured to store staples  132  therein, are positioned along staple lines  805  and  807 , for example, such that staples  132 , when they are deployed from staple cartridge  812 , are deployed in substantially parallel planes which are at least partially defined by staple lines  805  and  807 . 
     For each parallel plane described above, as a result of these upward and/or downward curvatures, staples  132  can be deployed along axes which are co-planar, but not parallel. More particularly, referring to  FIG. 39 , a first staple  132  (not illustrated in  FIG. 39 ) can be deployed from its staple cavity  803  along axis  853  and a second staple  132  can be deployed from its staple cavity  803  along axis  855 . While axis  853  and axis  855  can be co-planar, as illustrated in  FIG. 39 , axis  853  and axis  855  are not parallel. In some embodiments, the axes defined by staple cavities  803  can converge, as illustrated in  FIGS. 38 and 39 , or diverge, as illustrated in  FIGS. 35-37 . In various embodiments, the staple deployment axes can define an angle therebetween which is greater than or equal to 30 degrees. In other various embodiments, the axes can be substantially perpendicular and, in further embodiments, the axes can define an angle that is greater than ninety degrees. 
     As described above, an endocutter in accordance with an embodiment of the present invention can include a cutting member which is advanced through and guided by curved slots in the staple cartridge and/or anvil. For example, referring to  FIGS. 38-43 , staple cartridge  812  can include slot  864  which is configured to receive and guide cutting member  120 . Similar to the above, endocutter  800  can further include a drive bar for advancing cutting member  120  within slot  864  of staple cartridge  812 , however, owing to the direction and degree of the curvature of staple cartridge  812 , some drive bars may be largely unsuitable for use with endocutter  700  or  800 , for example. More particularly, the illustrated drive bars  126  and  226  in  FIGS. 4 and 24 , respectively, owing to their cross-sectional geometries, may not be particularly well-suited to flex in a substantially downward or substantially upward direction as required by endocutters  700  and  800 , respectively. Referring to  FIG. 26 , for example, the illustrated cross-section of drive bar  226  is substantially rectangular and is defined by height  257  and width  259 . As illustrated in  FIG. 26 , height  257  is substantially greater than width  259  and, as a result, the cross-section of the illustrated drive bar  226  has a moment of inertia with respect to height  257  that is substantially greater than the moment of inertia with respect to width  259 . Accordingly, the illustrated drive bar  226  is substantially less flexible with respect to height  257  than width  259  and may not be able to sufficiently bend in the substantially downward and upward directions described above. It is important to note that drive bars  126  and  226  are not limited to the configurations described above. On the contrary, drive bars  126  and  226  can have cross-sections in which the width is greater than the height. Any reference in this paragraph to drive bars  126  and  226  are references to the particular drive bars  126  and  226  that happen to be illustrated in  FIGS. 4 and 24 , respectively. 
     Referring to  FIGS. 41-43 , endocutter  800  can include drive bar  826  which, similar to drive bar  226 , is configured to advance cutting member  120 , or a curved cutting member, through curved slots in an end-effector. In various embodiments, drive bar  826  can include a cross-sectional geometry having a width  859  that is greater than its height  857 . In these embodiments, the moment of inertia of the cross-section with respect to height  857  is less than the moment of inertia with respect to width  859 . As a result, drive bar  826  can be more flexible with respect to height  857 , i.e., in the upward and downward directions, than with respect to width  859 . In at least one embodiment, width  859  can be approximately 0.12″ and height  857  can be approximately 0.05″. Although drive bar  826  is illustrated as having a rectangular cross-section, the invention is not so limited. On the contrary, the cross-section of drive bar  826  can include various embodiments in which the width of the drive bar cross-section is greater than its height. In at least one embodiment, drive bar  826  can include a cross-section defined by a width and a height wherein the width is greater than the height, and wherein the width defines an axis that is not parallel to an axis defined by cutting edge  124  of cutting member  120 . In various embodiments, as known in the art, cutting edge  124  can include a knife edge or a wire configured to conduct current therethrough. Furthermore, in various embodiments, the drive bar can be asymmetric with respect to centerline  224  of the distal end of shaft  116 , for example. In these embodiments, as a result, drive bar  826  can be predisposed to bending in a pre-determined direction. 
     Similar to drive bar  226 , drive bar  826  can be comprised of one material or, alternatively, several layers of material bonded together. As above, the flexibility of drive bar  826  can be pre-determined by the types of materials used and the arrangement of the layers within the drive bar. Referring to  FIG. 41 , cutting member body  822  can include slot  869  which is configured to receive the distal end of drive bar  826 . In the present embodiment, slot  869  is configured to receive drive bar  826  in a press-fit relationship, however, other means, such as adhesive or fasteners, can be used to secure drive bar  826  to cutting member  820 . Similar to the above, staple cartridge  812  can include a slot configured to receive and support drive bar  826  when it enters into staple cartridge  812 . In various embodiments, although not illustrated, anvil  834  could be configured to receive and support drive bar  826 . 
     As described above, the jaws of an endocutter can be placed on opposite sides of several layers of tissue, for example, and then closed onto the tissue. In the illustrated embodiments, referring to  FIG. 4 , jaw  108  can be pivoted between opened and closed positions with respect to jaw  110  via the interaction of inner portion  114  and outer sleeve  116  of shaft  106  in a known manner. Although not illustrated, jaw  108  is connected to jaw  110  via a pivot connection such that when inner portion  114  moves jaw  108  relative to outer sleeve  116 , jaw  108  is pivoted toward jaw  110 . Throughout the movement of jaw  108 , the proximal portion of jaw  108 , i.e., proximal portion  111 , is positioned closer to jaw  110  than its distal portion, i.e., distal portion  113 , until jaw  108  is brought into its final position opposite staple cartridge  112 . In this final, closed position, distal portion  113  and proximal portion  111  can be substantially equidistant from staple cartridge  112 . However, as a result of distal portion  113  being the last portion of jaw  108  to reach its final position, a portion of the tissue, or an artery, for example, can escape from between jaws  108  and  110  before distal portion  113  is moved into its final position. Accordingly, the surgeon may have to reopen the jaws and reposition the end-effector in an attempt to properly capture the tissue, or artery, therebetween. 
     As detailed below, an end-effector in accordance with an embodiment of the present invention can be configured to capture the tissue, or an artery, between the distal and proximal portions of the end-effector before the jaws are moved into their final position. In at least one embodiment, referring to  FIGS. 27-34 , jaw  608  can be pivotally connected to jaw  610  via pivot connection  609 . Pivot connection  609  can include first trunnion  615  and second trunnion  617  extending from jaw  608 , and, in addition, first slot  619  and second slot  621  in jaw  610 . Trunnions  615  and  617  can be sized and configured to fit within slots  619  and  621 , respectively, such that pivot connection  609  allows for relative rotational and translation movement between jaw  608  and jaw  610 . In other alternative embodiments, jaw  608  may include slots  619  and  621  and jaw  610  may include trunnions  615  and  617 , or any other combination thereof. 
     Referring to  FIGS. 28, 29 and 31  which schematically illustrate slot  619  in solid and slot  621  in dashes, trunnions  615  and  617  are configured to travel within slots  619  and  621 , respectively, and define the relative movement between jaws  608  and  610 . In the present embodiment, slots  619  and  621  define two different arcuate paths for trunnions  615  and  617 . More particularly, referring to  FIGS. 33 and 34 , slot  619  includes first portion  623 , second portion  625 , and intermediate portion  627  extending therebetween wherein slot  621  also includes first portion  623  and second portion  625 , however, slot  621  includes an intermediate portion, i.e., portion  629 , which is different than intermediate portion  627 . Referring to  FIG. 27 , as a result of slots  619  and  621  having different intermediate portions, slots  619  and  621  can cause jaw  608  to tilt, or otherwise move in a non-symmetrical manner, with respect to jaw  610  as it is opened and closed. Advantageously, referring to  FIGS. 30 and 32 , such an asymmetric motion, or tilting, can allow distal portion  613  of jaw  608  to be placed in close proximity to staple cartridge  612  before the intermediate portion of jaw  608 , i.e., portion  631 , is moved into its final position illustrated in  FIG. 32 . As a result, referring to  FIG. 30 , an end-effector in accordance with the above can be used to capture tissue, or an artery, between proximal end  611  and distal end  613  before intermediate portion  631  is moved into its final, or closed, position. As a result, the possibility of a portion of the tissue, or artery, escaping from between jaws  608  and  610  is reduced. In addition to the above, the distal ends of jaws  608  and  610  can be brought into close opposition to each other in order to grip delicate tissue, for example, without having to completely close the end-effector. 
     As outlined above, slots  619  and  621  can define different paths for trunnions  615  and  617 , respectively, when jaw  608  is moved between an open and a closed position. When jaw  608  is in its open position, referring to  FIG. 28 , trunnions  615  and  617  are positioned within first portions  623  of slots  619  and  621 . In this position, axis  633 , which is defined by trunnions  615  and  617 , is substantially collinear with axis  635  defined between first portions  623  of slots  619  and  621 . Thereafter, jaw  608  can be moved distally such that trunnions  615  and  617  move upward through slots  619  and  621 . Owing to the asymmetric configurations of slots  619  and  621 , referring to  FIG. 27  which illustrates jaw  108  in a partially closed position, trunnion  615  is elevated to a relatively higher position with respect to trunnion  617 , as evidenced by the tilting of axis  633 . In this position, an inner edge of jaw  608 , i.e., edge  639 , can be in closer proximity to staple cartridge  612  than an outer edge of jaw  608 , i.e., edge  641 . Advantageously, as a result, inner edge  639  can be brought into contact against the tissue, or an artery, for example, allowing the surgeon to evaluate the position of the end-effector with respect to the tissue, or artery, without having to bring the entire anvil  634  of jaw  608  against the tissue. This feature may be particularly advantageous when the end-effector is positioned around a pulmonary artery as pulmonary arteries are especially susceptible to rupture. 
     After the tissue, or artery, has been captured between the proximal and distal ends of the end-effector, referring to  FIGS. 31 and 32 , jaw  608  can be moved into its final, or closed, position with respect to staple cartridge  612 . In this position, axis  633 , which is defined by trunnions  615  and  617 , can be substantially collinear with axis  637  defined between second portions  625  of slots  619  and  621 . Furthermore, in this final position, intermediate portion  631 , distal portion  613  and proximal portion  611  can be equidistant from staple cartridge  612 . Similarly, outer edge  641  and inner edge  639  can also be positioned equidistant with respect to staple cartridge  612 . In this final position, tissue, or an artery, for example, can be securely retained between jaws  608  and  610 . Although the above-described embodiments include a curved end-effector, the invention is not so limited. On the contrary, the above features can be utilized with a linear end-effector, for example, to achieve the advantages described above. 
     In various embodiments, slots  619  and  621  can define paths having different centerlines wherein each centerline can be defined as the line equidistant from the top and bottom surfaces of each slot. For example, referring to  FIGS. 33 and 34 , slot  619  can include bottom surface  642  and top surface  643  which define a centerline therebetween that is different than the centerline defined by bottom surface  645  and top surface  647  of slot  621 . In these embodiments, slots  619  and  621  can be configured to closely retain trunnions  615  and  617  between these top and bottom surfaces such that axis  633  of trunnions  615  and  617  substantially travels along the centerlines of slots  619  and  621 . In various embodiments, jaws  608  and  610  can be configured such that trunnions  615  and  617  contact bottom surfaces  642  and  645  of slots  619  and  621 . In these embodiments, jaw  608  can be biased by a spring, for example, such that trunnions  615  and  617  are positioned against bottom surfaces  642  and  645  throughout the movement of jaw  608 . Owing to different profiles for bottom surfaces  642  and  645 , the advantages described above can be achieved. 
     As described above, once the jaws of the end-effector are closed onto the layers of tissue, for example, staples can be deployed into the tissue. However, oftentimes, the layers of tissue are very thin and the staples may not properly capture the tissue therein. To ameliorate this problem, as known in the art, buttress material can be placed on one or both sides of the tissue to support the tissue as it is being stapled. In such embodiments, the purchase of the staples is improved and the clamping force of the staples may be spread more evenly across the buttress material. In various embodiments, the buttress material can be comprised of a bioabsorbable material such that it can dissolve away during the healing process. Previously, however, the buttress material has been provided in linear strips which are configured to accommodate linear staple lines and end-effectors. Such linear strips may be unsuitable for use with endocutters having a curved end-effector configured to deploy staples in curved staple lines. 
     In accordance with an embodiment of the present invention, referring to  FIGS. 44-47 , curved staple cartridge  912  can be configured to receive a curved piece, or pieces, of buttress material thereon, such as buttress material  971 . Curved buttress material  971  can include inner edge  973  which can be configured to substantially parallel the inner radius of curvature of jaw  910 , and, in addition, outer edge  975  which can be configured to substantially parallel the outer radius of curvature of jaw  910 . In some embodiments, referring to  FIG. 47 , staple cartridge  912  can include lip  977  extending therefrom which is configured to retain buttress material  971  on staple cartridge  912 . More particularly, lip  977 , as illustrated, can be configured to limit lateral movement of buttress material  971  with respect to staple cartridge  912  and, although not illustrated, lip  977  can also be configured to extend distal to and/or proximal to the ends of the buttress material to limit relative axial movement between buttress material  977  and staple cartridge  912 . Similar to the above, curved anvil  934  can be configured to receive a piece, or pieces, of curved buttress material thereon, such as buttress material  979  and  981 , for example. Referring to  FIG. 47 , anvil  934  can include several lips  982  which are configured to limit relative movement between buttress material  979  and  981  and anvil  934 . In various embodiments, an adhesive, such as cyanoacrilate, for example, can be applied to the buttress material, anvil and/or staple cartridge to further limit the movement of the buttress material or otherwise prevent the mobilization thereof. 
     As a result of the above, a surgeon may be able to position the end-effector into a surgical site without the buttress material falling off or moving relative to the staple cartridge and/or anvil. Once positioned, cutting member  120  can be advanced to cut buttress material  971 . More specifically, referring to  FIG. 47 , cutting edge  924  can be aligned with buttress material  971  such that it cuts the buttress material as cutting member  920  is advanced through staple cartridge  912 . However, in some circumstances, the cutting member may at least partially dislodge the buttress material relative to the staple cartridge. This relative movement may especially occur when the buttress material is thick, or, the cutting member must cut more than one piece of buttress material at a time. To ameliorate this problem, the buttress material may include a series of perforations, for example, positioned along the path in which the cutting member will cut the buttress material. In these embodiments, these perforations may be formed along a radius of curvature which is parallel to and positioned intermediate two curved staple rows. In other various embodiments, the buttress material may include other features which disrupt the cross-sectional thickness of the buttress material to facilitate the cutting of the buttress material. As a result of the above, less force may be required to cut the buttress material and, accordingly, it is less likely the buttress material may slide, for example, when it is cut. 
       FIGS. 48-50  illustrate another surgical instrument of the present invention. As can be seen in these Figures, the surgical instrument  1000  includes an end-effector  1002  that has a first jaw  1008  and a second jaw  1010 . The second jaw  1010  may comprise a channel  1038  that is configured to operably support a staple cartridge  1012  therein. Staple cartridge  1012  may be removably supported in the channel  1038  or, in various embodiments, staple cartridge  1012  may form an integral part of the second jaw  1010 . The surgical instrument  1000  further includes a movable anvil  1034  that may be movably coupled to the lower jaw  1010  in the various manners described above or in other manners that are known in the art. 
     In the embodiment depicted in  FIGS. 48-50 , the end effector  1002  has a distal end generally designated as  1040 . As can further be seen in those Figures, the staple cartridge  1012  has a blunt first tip portion  1088  thereon. The first tip portion  1088  may be integrally formed (molded, machined, etc.) on the distal end  1013  of the staple cartridge  1012  or it may comprise a separate piece that may be formed with a cavity  1089  ( FIG. 50 ) configured to receive a nose  1083  of a conventional staple cartridge  1012 . The first tip portion  1088  can include snap features  1090  ( FIG. 50 ) or other suitable retainer portions formed therein to retainingly mate with complementary retention grooves  1084  formed in the nose  1083 . In addition, or in the alternative, the first tip portion  1088  may be affixed to the cartridge  1012  by adhesive such as, for example, cyanoacrylates, light-curable acrylics, polyurethanes, silicones, epoxies, and ultra-violet curable adhesives such as Henkel Loctite®. In other embodiments, a combination of snap features and grooves may be provided in both the staple cartridge  1012  and the first tip portion  1088 . Still other forms of fasteners and fastener arrangements may be used to affix the first tip portion  1088  to the staple cartridge  1012 . In other embodiments, the first tip portion  1088  may be affixed to the channel  1038 . As can be seen in  FIG. 50 , the first tip portion  1088  has a first upwardly extending curved outer surface. 
     Similarly, in this embodiment, the anvil  1034  may be equipped with a second tip portion  1092 . The second tip portion  1092  may be integrally formed (molded, machined, etc.) on the distal end  1085  of the anvil  1034  or it may comprise a separate piece that may be formed with a cavity  1093  configured to receive an end portion of a conventional anvil  1034  with snap features  1094  or other suitable retainer portions formed therein to retainingly mate with complementary retention grooves  1086  formed in distal end  1085 . In addition, or in the alternative, the second tip portion  1092  may be affixed to the anvil  1034  by adhesive such as, for example, cyanoacrylates, light-curable acrylics, polyurethanes, silicones, epoxies, and ultra-violet curable adhesives such as Henkel Loctite®. In other embodiments, a combination of snap features and grooves may be provided in both distal end  1085  and the second tip portion  1092 . Still other forms of fasteners may be used to affix the second tip portion  1092  to the anvil  1034 . As can be seen in  FIG. 50 , the second tip portion  1092  has a downwardly extending substantially curved outer surface. 
     In various embodiments, the first tip portion  1088  and the second tip portion  1092  may be fabricated from a variety of different materials that may be identical to or different from the materials from which the staple cartridge  1012  and anvil  1034  are manufactured. For example, the first tip portion  1088  and the second tip portion  1092  may be manufactured from soft plastic, rubber, etc. The first tip portion  1088  and the second tip portion  1092  may be fabricated from the same or different materials. 
     In various embodiments, the first tip portion  1088  and the second tip portion  1092  are shaped such that their respective outer surfaces  1088 ′,  1092 ′ cooperate to substantially form a substantially blunt end effector nose generally designated as  1096  that, in one exemplary embodiment, has a paraboloid surface  1098  when the anvil  1034  is in the closed position as shown in  FIG. 50 . As used herein, the term “paraboloid surface” means a surface having parabolic sections parallel to a single coordinate axis and elliptic sections perpendicular to that axis. Those of ordinary skill in the art will appreciate that when employing various embodiments of the instrument  1000 , as long as the surgeon can see one or the other of the first tip portion or second tip portion, the surgeon will know where the other tip portion is, even if it is behind tissue or other structures. In addition, the unique and novel tip configurations permit the surgeon to pass the anvil and/or channel around tissue without great risk of incidental trauma to adjacent tissues. Furthermore, when in the closed orientation as depicted in  FIGS. 49 and 50 , these embodiments are particularly well suited for use as a dissector for separating and manipulating tissues. 
     The first tip portion and the second tip portion have been described and depicted in the Figures as being used in connection with a curved end effector. Those of ordinary skill in the art will readily appreciate, however, that the first and second tip portions may be used in connection with a variety of different end effector configurations such as linear endocutters and other types of end effectors without departing from the spirit and scope of the present invention. Thus, the first and second tip portions described above should not be limited solely to use in connection with curved endocutters/staplers. 
     As was described above, the first tip portion may be constructed for attachment to the distal end of a conventional staple cartridge or it may be integrally formed on the end of the staple cartridge. In still other embodiments, the first tip portion may be constructed for attachment to a distal end of the channel or it may be integrally formed on the distal end of the channel. Similarly, the second tip portion may be constructed for attachment to a conventional endocutter anvil or it may be integrally formed on the distal end of the anvil. In those applications wherein the first tip portion and/or second tip portion are fabricated separately from the cartridge and anvil, respectively, the tip portions may be supplied as a kit for retrofitting onto the cartridge and anvil by the end user. For example, in such arrangements, the tip portions may be presterilized and packaged and be configured to snap onto or otherwise attach to the staple cartridge and anvil or channel and anvil, whichever the case may be. 
     The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the device can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the device can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application. 
     Preferably, the invention described herein will be processed before surgery. First, a new or used instrument is obtained and if necessary cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility. 
     While this invention has been described as having exemplary designs, the present invention may be further modified within the spirit and scope of the disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.