Patent Publication Number: US-11642129-B2

Title: Staple cartridge and drive member for surgical instrument

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/961,504, filed Jan. 15, 2020, the entire disclosure of which is incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     The field of the present disclosure relates to medical instruments, and more particularly to tissue sealing instruments for use in surgeries. Even more particularly, the present disclosure relates to a surgical stapling instrument having an improved staple cartridge and drive member (i.e., staple actuator) that allows for a smaller and more compact device. 
     Minimally invasive medical techniques are intended to reduce the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. One effect of minimally invasive surgery, for example, is reduced post-operative hospital recovery times. The average hospital stay for a standard open surgery is typically significantly longer than the average stay for an analogous minimally invasive surgery (MIS). Thus, increased use of MIS could save millions of dollars in hospital costs each year. While many of the surgeries performed each year in the United States could potentially be performed in a minimally invasive manner, only a portion of the current surgeries uses these advantageous techniques due to limitations in minimally invasive surgical instruments and the additional surgical training involved in mastering them. 
     Improved surgical instruments such as tissue access, navigation, dissection and sealing instruments have enabled MIS to redefine the field of surgery. These instruments allow surgeries and diagnostic procedures to be performed with reduced trauma to the patient. A common form of minimally invasive surgery is endoscopy, and a common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient&#39;s abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately one-half inch or less) incisions to provide entry ports for laparoscopic instruments. 
     Laparoscopic surgical instruments generally include an endoscope (e.g., laparoscope) for viewing the surgical field and tools for working at the surgical site. The working tools are typically similar to those used in conventional (open) surgery, except that the working end or end effector of each tool is separated from its handle by an extension tube (also known as, e.g., an instrument shaft or a main shaft). The end effector can include, for example, a clamp, grasper, scissor, stapler, cautery tool, linear cutter, or needle holder. 
     To perform surgical procedures, the surgeon passes working tools through cannula sleeves to an internal surgical site and manipulates them from outside the abdomen. The surgeon views the procedure from a monitor that displays an image of the surgical site taken from the endoscope. Similar endoscopic techniques are employed in, for example, arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like. 
     Minimally invasive telesurgical robotic systems are being developed to increase a surgeon&#39;s dexterity when working on an internal surgical site, as well as to allow a surgeon to operate on a patient from a remote location (outside the sterile field). In a telesurgery system, the surgeon is often provided with an image of the surgical site at a control console. While viewing a three dimensional image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master input or control devices of the control console, which in turn control motion of the servo-mechanically operated slave instruments. 
     The servomechanism used for telesurgery will often accept input from two master controllers (one for each of the surgeon&#39;s hands) and may include two or more robotic arms on each of which a surgical instrument is mounted. Operative communication between master controllers and associated robotic arm and instrument assemblies is typically achieved through a control system. The control system typically includes at least one processor that relays input commands from the master controllers to the associated robotic arm and instrument assemblies and back from the instrument and arm assemblies to the associated master controllers in the case of, for example, force feedback or the like. One example of a robotic surgical system is the DA VINCI™ system commercialized by Intuitive Surgical, Inc. of Sunnyvale, Calif. 
     A variety of structural arrangements have been used to support the surgical instrument at the surgical site during robotic surgery. The driven linkage or “slave” is often called a robotic surgical manipulator, and exemplary linkage arrangements for use as a robotic surgical manipulator during minimally invasive robotic surgery are described in U.S. Pat. No. 7,594,912 (filed Sep. 30, 2004), 6,758,843 (filed Apr. 26, 2002), 6,246,200 (filed Aug. 3, 1999), and 5,800,423 (filed Jul. 20, 1995), the full disclosures of which are incorporated herein by reference in their entirety for all purposes. These linkages often manipulate an instrument holder to which an instrument having a shaft is mounted. Such a manipulator structure can include a parallelogram linkage portion that generates motion of the instrument holder that is limited to rotation about a pitch axis that intersects a remote center of manipulation located along the length of the instrument shaft. Such a manipulator structure can also include a yaw joint that generates motion of the instrument holder that is limited to rotation about a yaw axis that is perpendicular to the pitch axis and that also intersects the remote center of manipulation. By aligning the remote center of manipulation with the incision point to the internal surgical site (for example, with a trocar or cannula at an abdominal wall during laparoscopic surgery), an end effector of the surgical instrument can be positioned safely by moving the proximal end of the shaft using the manipulator linkage without imposing potentially hazardous forces against the abdominal wall. Alternative manipulator structures are described, for example, in U.S. Pat. No. 6,702,805 (filed Nov. 9, 2000), 6,676,669 (filed Jan. 16, 2002), 5,855,583 (filed Nov. 22, 1996), 5,808,665 (filed Sep. 9, 1996), 5,445,166 (filed Apr. 6, 1994), and 5,184,601 (filed Aug. 5, 1991), the full disclosures of which are incorporated herein by reference in their entirety for all purposes. 
     During the surgical procedure, the telesurgical system can provide mechanical actuation and control of a variety of surgical instruments or tools having end effectors that perform various functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, dissecting tissue, or the like, in response to manipulation of the master input devices. Manipulation and control of these end effectors is a particularly beneficial aspect of robotic surgical systems. Such mechanisms should be appropriately sized for use in a minimally invasive procedure and relatively simple in design to reduce possible points of failure. In addition, such mechanisms should provide an adequate range of motion to allow the end effector to be manipulated in a wide variety of positions. 
     Surgical clamping and cutting instruments (e.g., non-robotic linear clamping, stapling, and cutting devices, also known as surgical staplers; and electrosurgical vessel sealing devices) have been employed in many different surgical procedures. For example, a surgical stapler can be used to resect a cancerous or anomalous tissue from a gastro-intestinal tract. Many known surgical clamping and cutting devices, including known surgical staplers, have opposing jaws that clamp tissue and an articulated knife to cut the clamped tissue. 
     Surgical clamping and cutting instruments are often deployed into restrictive body cavities (e.g., through a cannula to inside the pelvis). Accordingly, it is desirable for the surgical clamping and cutting instrument to be both compact and maneuverable for best access to and visibility of the surgical site. Known surgical clamping and cutting instruments, however, may fail to be both compact and maneuverable. For example, known surgical staplers may lack maneuverability with respect to multiple degrees of freedom (e.g., Roll, Pitch, and Yaw) and associated desired ranges of motion. 
     Conventional surgical clamping and cutting instruments often include a staple cartridge designed to fit within the movable jaw of the end effector. The staple cartridge typically contains multiple rows of staple assemblies that each includes at least one staple and an associated staple driver or pusher. The staple pusher holds the staple in place prior to use. When the instrument is actuated, a drive member or staple actuator is configured to translate distally through the end effector and advance the staple pushers substantially perpendicular to the movable jaw, thereby driving the staples into the tissue. 
     The requisite size and shape of the drive member, however, limits the ability of the designer to reduce the size and shape of the overall surgical instrument. Typical drive members include a shuttle having one or more inclined distal surfaces or ramps configured to drive the staple pushers and their associated staples upwards into tissue as the drive member advances distally through the end effector. The ramps, however, must extend almost all the way to the top surface of the staple cartridge in order to drive the staples into the tissue when the instrument is actuated. To accommodate the ramps of the drive member, the staple cartridge typically includes a somewhat bulky nose extending from its distal end that prevents the ramps from contacting tissue when it reaches the most distal point of its translation through the end effector. The staple cartridge nose increases the length of the surgical instrument and may inhibit access to certain areas of the surgical site. 
     In addition, the staple cartridge typically includes extensive cutouts through its elongate body to provide sufficient clearance for the passage of the drive member ramps. These cutouts reduce the overall material strength of the staple cartridge and provide challenges and extra costs to the manufacturing process. 
     Accordingly, while the new telesurgical systems and devices have proven highly effective and advantageous, still further improvements would be desirable. In general, it would be desirable to provide improved surgical instruments that are more compact and maneuverable to enhance the efficiency and ease of use of minimally invasive systems. More specifically, it would be beneficial to create improved drive members and/or staple cartridges that will allow for the design of even more compact and maneuverable surgical instruments. 
     SUMMARY 
     The following presents a simplified summary of the claimed subject matter in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview of the claimed subject matter. It is intended to neither identify key or critical elements of the claimed subject matter nor delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts of the claimed subject matter in a simplified form as a prelude to the more detailed description that is presented later. 
     In one aspect of the invention, a surgical instrument comprises a staple cartridge having a housing containing a staple pusher and a staple. The surgical instrument further includes a drive member or staple actuator configured to translate longitudinally through the instrument. The drive member includes a substantially elongate body and a projection extending laterally outward from the body. The lateral projection is configured to engage the staple pusher and drive the staple pusher in a direction transverse to the longitudinal axis of the staple cartridge housing. The lateral projection of the drive member has a height substantially less than the height of the staple cartridge housing, thereby requiring less clearance as it translates through the staple cartridge. In addition, the lateral projection has a smaller footprint than conventional drive members resulting in a more compact distal tip on the staple cartridge, which allows for a more compact and maneuverable surgical instrument. 
     In a preferred embodiment, the surgical instrument comprises an end effector with a first fixed jaw and a second jaw. The second jaw is configured to move relative to the first jaw from an open to a closed position. The staple cartridge is coupled to the second jaw and the drive member is configured to translate distally and retract proximally through the end effector. The drive member includes a projection or shuttle fin extending laterally outward to engage the staple pushers within the staple cartridge as the drive member is translated therethrough. The height of the shuttle fin is substantially smaller than the overall height of the drive member and the staple cartridge, preferably less than half the height of the staple cartridge and more preferably less than a fourth the height of the staple cartridge. This configuration minimizes the volume of space occupied by the shuttle fin when it is advanced to the distal tip of the staple cartridge, allowing for the design of a more compact nose. In addition, the relatively smaller shuttle fin reduces the volume of clearance space required for the drive member to translate through the staple cartridge, which allows the staple cartridge to be manufactured with more material and less cutouts than conventional designs, thereby increasing the material strength of the cartridge and decreasing the cost and complexity of the molding process. 
     In an exemplary embodiment, the staple cartridge comprises a drive rod pivotally coupled to the staple pusher. The drive rod includes a proximal end configured for receiving the shuttle fin of the drive member upon distal translation of the drive member through the staple cartridge. The engagement of the shuttle fin with the proximal end of the drive rod causes the drive rod to pivot about a hinge and drive the staple pusher in a perpendicular direction relative to the longitudinal axis of the staple cartridge. The drive rod may have an elongate portion extending proximally from the staple pusher. The elongate portion pivots from a substantially longitudinal orientation to a substantially perpendicular orientation relative to the staple cartridge. After it has been pivoted to the perpendicular orientation, the elongate portion of the drive rod has a length or height sufficient to advance the staple pusher close enough to the top surface of the staple cartridge such that the staples are driven into the patient&#39;s tissue. 
     In certain embodiments, the surgical instrument further includes an actuation mechanism in contact with the central portion of the drive member. The actuation mechanism is configured to advance the drive member distally through the end effector and to retract the drive member proximally through the end effector. In an exemplary embodiment, the actuator includes a control device of a robotic telesurgical system that may, for example, allow for mechanical actuation and control of the surgical instrument to perform a variety of functions, such as grasping a blood vessel, dissecting tissue, or the like, in response to manipulation of master input devices located remotely from the surgical instrument. 
     In another aspect, a surgical instrument comprises a staple cartridge having a housing containing a staple, a staple pusher and a drive rod pivotally coupled to the staple pusher. The instrument further includes a drive member configured to translate longitudinally through the housing and engage the drive rod to pivot the drive rod with respect to the staple pusher and thereby advance the staple pusher and associated staple in a direction transverse to the longitudinal axis of the housing. The drive rod is preferably sized and configured to pivot about the staple pusher and advance the staple a sufficient distance to drive the staple into tissue when the instrument is actuated. 
     In the preferred embodiment, the drive rod includes an elongate portion with a proximal end for receiving the drive member and a curved portion coupled to the staple support. Distal translation of the drive member engages the proximal end of the drive rod and advances it distally, causing the curved portion of the drive rod to deform and pivot about the staple pusher such that the staple pusher and staple are driven in a direction substantially perpendicular to the longitudinal axis of the staple cartridge. The elongate portion of the drive rod preferably extends in the longitudinal direction near the bottom surface of the staple cartridge housing prior to actuation. During actuation, the elongate portion has a length sufficient to advance the staple pusher substantially to the top surface of the staple cartridge. Thus, the pivotable drive rod and lateral projection of the present disclosure together perform substantially the same function as a ramp on a conventional drive member, thereby allowing for the design of a drive member without such a ramp. 
     In another aspect, a staple cartridge for a surgical instrument comprises a staple support, such as a staple driver or pusher, comprising an elongate body with a top surface configured for receiving a staple and a drive rod pivotally coupled to the staple support and configured to translate the staple support in a direction transverse to the elongate body. The staple cartridge may be configured for use with a surgical instrument having a drive member, such as described herein. 
     In certain embodiments, the cartridge further includes a hinge pivotally coupling the drive rod to the staple support. The hinge may be integral with the drive rod. The drive rod comprises an elongate portion coupled to a curved portion, which is coupled to the elongate body of the staple support. The elongate portion may have an end surface, wherein movement of the end surface in a first direction causes movement of the staple support in a second direction transverse to the first direction. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. Additional features of the disclosure will be set forth in part in the description which follows or may be learned by practice of the disclosure 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of the present surgical instruments will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which: 
         FIG.  1    is a perspective view of an illustrative surgical instrument having an end effector mounted to an elongated shaft, and an actuation mechanism. 
         FIG.  1 A  is a perspective top view of the distal end portion of an illustrative surgical instrument with the jaws in the open position; 
         FIG.  1 B  is a bottom perspective view with parts separated of a representative staple cartridge for an illustrative surgical instrument; 
         FIG.  1 C  shows an enlarged view of the cooperative relationship between a plurality of conventional staple pushers and staples which form part of the staple cartridge of  FIG.  1 B ; 
         FIG.  1 D  is a perspective bottom view of the distal end portion of the surgical instrument of  FIG.  1 A ; 
         FIG.  2 A  is a perspective side view of a staple assembly according to certain embodiments of the present disclosure; 
         FIG.  2 B  is a perspective side view of a drive member according to certain embodiments of the present disclosure; 
         FIG.  3    is a perspective top view of the staple assembly of  FIG.  2 A ; 
         FIG.  4    is a perspective side view of one portion of a staple cartridge with the drive member of  FIG.  2 B  according to certain embodiments of the present invention; 
         FIG.  5    is a side view illustrating the actuation of the staple assembly of  FIG.  2 A ; 
         FIGS.  6 A and  6 B  illustrate a conventional staple cartridge; 
         FIG.  7    is a perspective top view of one portion of a staple cartridge according to certain embodiments of the present invention; 
         FIG.  8    is a perspective view of the end portion of an illustrative surgical instrument with parts removed; 
         FIG.  9 A  is a partial cross-sectional perspective view of the actuation mechanism for a drive member in accordance with the surgical instrument of  FIG.  1   ; 
         FIG.  9 B  is a partial cross-sectional side view of the actuation mechanism for a drive member in accordance with the surgical instrument of  FIG.  1   ; 
         FIG.  10    is a cross-sectional side view of the end portion of the illustrative surgical instrument of  FIG.  1   ; 
         FIG.  11    illustrates a top view of an operating room employing a robotic surgical system utilizing aspects of the present invention; and 
         FIG.  12    illustrates a simplified side view of a robotic arm assembly that is usable with various aspects of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Particular embodiments of the present surgical instruments are described hereinbelow with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure and may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in any unnecessary detail. Like numbers in two or more figures represent the same or similar elements. Furthermore, elements and their associated aspects that are described in detail with reference to one embodiment may, whenever practical, be included in other embodiments in which they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment and is not described with reference to a second embodiment, the element may nevertheless be claimed as included in the second embodiment. Moreover, the depictions herein are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the system or illustrated components. 
     While the following disclosure is presented with respect to a linear surgical stapler where staples are sequentially fired, it should be understood that the features of the presently described surgical instruments may be readily adapted for use in any type of surgical clamping, cutting, ligating, dissecting, clipping, cauterizing, suturing and/or sealing instrument, whether or not the surgical instrument applies a fastener. For example, the presently described drive member and actuation mechanism may be employed in an electrosurgical instrument wherein the jaws include electrodes for applying energy to tissue to treat (e.g., cauterize, ablate, fuse, or cut) the tissue. The surgical clamping and cutting instrument may be a minimally invasive (e.g., laparoscopic) instrument or an instrument used for open surgery. 
     The embodiments of the present disclosure may also be incorporated into the a variety of different surgical instruments, such as those described in commonly-assigned, co-pending U.S. patent application Ser. Nos. 16/205,128, 16/427,427, 16/678,405, 16/904,482, 17/081,088 and 17/084,981 and International Patent Nos. PCT/US2019/107646, PCT/US2019/019501, PCT/US2019/062344, PCT/US2020/54568, PCT/US2019/064861, PCT/US2019/062768, PCT/2020/025655, PCT/US2020/056979, PCT/2019/066513, PCT/US2020/020672, PCT/US2019/066530 and PCT/US2020/033481, the complete disclosures of which are incorporated by reference herein in their entirety for all purposes as if copied and pasted herein. 
     Additionally, the features of the presently described surgical stapling instruments may be readily adapted for use in surgical instruments that are activated using any technique within the purview of those skilled in the art, such as, for example, manually activated surgical instruments, powered surgical instruments (e.g., electro-mechanically powered instruments), robotic surgical instruments, and the like. 
       FIG.  1    is a perspective view of an illustrative surgical stapling instrument  100  in accordance with certain embodiments of the present disclosure having a handle assembly  102 , and an end effector  110  mounted on an elongated shaft  106  of the surgical stapling instrument  100 . End effector  110  includes a stationary jaw  111  and a moveable jaw  112 . Handle assembly  102  includes a stationary handle  102   a  and a moveable handle  102   b , which serves as an actuator for surgical instrument  100 . 
     In certain embodiments, handle assembly  102  may include input couplers (not shown) instead of, or in addition to, the stationary and movable handles. The input couplers provide a mechanical coupling between the drive tendons or cables of the instrument and motorized axes of the mechanical interface of a drive system. The input couplers may interface with, and be driven by, corresponding output couplers (not shown) of a telesurgical surgery system, such as the system disclosed in U.S. Pub. No. 2014/0183244A1, the entire disclosure of which is incorporated by reference herein. The input couplers are drivingly coupled with one or more input members (not shown) that are disposed within the instrument shaft  106  and end effector  110 . Suitable input couplers can be adapted to mate with various types of motor packs (not shown), such as the stapler-specific motor packs disclosed in U.S. Pat. No. 8,912,746, or the universal motor packs disclosed in U.S. Pat. No. 8,529,582, the disclosures of both of which are incorporated by reference herein in their entirety. Further details of known input couplers and surgical systems are described, for example, in U.S. Pat. Nos. 8,597,280, 7,048,745, and 10,016,244. Each of these patents is hereby incorporated by reference in its entirety. 
     Actuation mechanisms of surgical instrument  100  may employ drive cables that are used in conjunction with a system of motors and pulleys. Powered surgical systems, including robotic surgical systems that utilize drive cables connected to a system of motors and pulleys for various functions including opening and closing of jaws, as well as for movement and actuation of end effectors are well known. Further details of known drive cable surgical systems are described, for example, in U.S. Pat. Nos. 7,666,191 and 9,050,119 both of which are hereby incorporated by reference in their entireties. While described herein with respect to an instrument configured for use with a robotic surgical system, it should be understood that the wrist assemblies described herein may be incorporated into manually actuated instruments, electro-mechanical powered instruments, or instruments actuated in any other way. 
       FIG.  1 A  illustrates the distal end portion of surgical instrument  100 , including an end effector  110  having a first jaw  111  and a second jaw  112 , a clevis  140  for mounting jaws  111 ,  112  to the instrument, and an articulation mechanism, such as a wrist  160 . In certain embodiments, second jaw  112  is a movable jaw configured to move from an open position to a closed position relative to first jaw  111 . In other embodiments, first jaw  111  is a movable jaw configured to move between open and closed positions relative to second jaw  112 . In still other embodiments, both jaws  111 ,  112  are movable relative to each other. First jaw  111  may include an anvil  115  having staple-forming pockets  116  (see  FIG.  1 D ). In the open position, a fresh stapling cartridge  122  (sometimes referred to as a reload and shown more clearly in  FIG.  1 B ) can be loaded into movable jaw  112  and tissue may be positioned between the jaws  111 ,  112 . In the closed position, jaws  111 ,  112  cooperate to clamp tissue such that cartridge  122  and the anvil  115  are in close cooperative alignment. 
     Referring now to  FIGS.  1 B and  1 C , a representative cartridge  122  is shown to illustrate the basic features of a conventional surgical staple instrument. Cartridge  122  may include a plurality of staples  124  supported on corresponding staple pushers  126  provided within respective staple apertures  127  formed in cartridge  122 . A drive member  150  (shown in  FIG.  2 B ), may be translated distally through end effector  110  to sequentially act on staple pushers  126 , driving them upwardly, thereby moving staples  124  into deforming contact with anvil  115  (discussed in more detail below). Cartridge  122  may be removably received within movable jaw  112  or, in single use embodiments, may be manufactured as part of movable jaw  112 . 
       FIGS.  2 A and  3    illustrate a preferred embodiment of a staple assembly  200  according to the present invention. As shown, staple assembly  200  includes one or more staple pushers  126  (preferably about 2 to 4) each having a substantially elongate body  201  with a top surface  202  configured for receiving one or more staples  124  (not shown in  FIG.  2 A ). In an exemplary embodiment, staple pusher(s)  126  include one or more supporting elements  206  extending above top surface  202  for providing support to staples  124  when they are resting on top surface  202 . Of course, other suitable geometric designs of staple pusher  126  may be used to receive and hold staple  124  in accordance with the present invention. For example, pusher  126  may have a longitudinal recess (not shown) for receiving staple  124 , as is described in commonly-assigned, co-pending International Patent Application No. PCT/US2020/033481, filed May 18, 2020, the complete disclosure of which is incorporated herein by reference for all purposes. Alternatively, staple pusher  126  may have a flatter upper surface (i.e., without a recess or pocket) that allows the backspan of staple  124  to rest thereon, as is described in commonly-assigned, provisional patent application No. 62,783,460. The complete disclosure of both applications are hereby incorporated by reference in their entirety for all purposes. 
     Staple assembly  200  further comprises one or more drive rods  204  coupled to staple pusher(s)  126 . Drive rods  204  each comprise a curved portion  208  preferably coupled to the side surface of staple pusher body  201  and an elongate portion  210  extending in a substantially longitudinal direction away from staple pusher  202 . Elongate portions  210  each include a proximal end  212  for engagement with drive member  150  (discussed below) and a bottom surface  214  configured to reside on, or near, the bottom inside surface of suture cartridge  122 . In an exemplary embodiment, elongate portion  210  of drive rod  204  further includes an inclined surface or ramp  215  between bottom surface  214  and curved portion  208 . Ramp  215  serves to elevate staple pusher body  201  above the proximal part of elongate portion  210  to provide room for adjacent staple pushers  126  in cartridge  122  (see  FIG.  4    wherein each staple pusher body  201  resides above the proximal portion of the drive rod  204  for the adjacent staple pusher  126 ). Ramp  215  may also provide additional leverage to enable elongate portion  210  to pivot about staple pusher  126 , as discussed in more detail below. 
     Referring now to  FIG.  5   , curved portions  208  function as a living hinge or flexure bearing between drive rods  204  and staple pushers  126 . To that end, curved portions  208  preferably have a shape and size specifically designed to allow drive rod  204  to pivot or rotate with respect to staple pusher  126 . Curved portions  208  may include a thinned material portion (not shown) that deforms as drive rod  204  is pivoted about pusher body  201  to facilitate the formation of the living hinge. Curved portions  208  (and the entire drive rod  204 ) may be formed integrally with staple pusher  126 , or they may be formed separately and then suitably coupled thereto. As shown, a sufficient force applied to proximal end  212  of drive rod  204  causes drive rod  204  to pivot about the hinge formed by curved portion  208 , thereby driving staple pusher  126  in a substantially perpendicular direction to the applied force. In particular, curved portion  208  deforms from the curved orientation shown in the leftmost picture to a substantially straight orientation as shown in the rightmost picture. This deformation allows elongate portion  210  to rotate from the longitudinal orientation to the perpendicular orientation, thereby driving staple pusher  126  vertically relatively to staple cartridge  122 . Of course, other suitable hinges may be used with the present disclosure, such as a pin, bolt, joint hinge, strap hinge, butterfly, barrel, piano, pivot, spring and the like. 
     Staple pusher  126  preferably includes a groove or other recess  211  in top surface  202  for receiving a projection (not shown) in staple cartridge  122 . Recess  211  is sized to engage with the cartridge projection and allow for movement of staple pusher  126  in a substantially perpendicular direction to the longitudinal axis of the cartridge housing. The cartridge projection preferably cooperates with a vertical rail member to restrict movement of projection and staple pusher  126  to a substantially vertical path. Recess  211  and the cartridge projection ensure that when drive member  150  is translated distally and engages with proximal end  212  of drive rods  204 , that staple pusher  126  and staple  124  do not also move distally and are instead driven upwards relative to cartridge  122  so that staple  124  is ultimately driven into the tissue when movable jaw  112  engages fixed jaw  110 . In other embodiments, pusher  126  may be formed with a groove or recess in the side surface of body  201 . For example, pusher  124  may have a projection or recess that cooperates with an associated vertical groove or recess in the staple cartridge. In alternative embodiments, other mechanisms can be used to ensure that staple pusher  124  is driven upwards into fixed jaw  110  during actuation. For example, cartridge  122  may include rails or other material at the distal end of each pusher  126  or staple assembly to prevent distal movement of staple assemblies when drive member  150  engages drive rods  204 . 
     Elongate portion  210  of drive rod(s)  204  preferably has a length sufficient to drive staple pusher  126  close to, at, or even above, the top surface of staple cartridge  122 . Thus, as drive member  150  moves proximal end  212  of drive rods  204  to a point where drive rods  204  are substantially perpendicular to their original orientation prior to actuation, staple pusher  126  has been advanced or lifted through staple cartridge  122  to the point where staple  124  can be driven into the patient&#39;s tissue. The exact length of elongate portion  210  will, of course, depend on the height of staple cartridge  122 , and/or the height of staples  124 , which may vary depending on the surgical application. 
     Of course, it will be recognized that the present disclosure is not limited to a drive rod pivotally coupled to staple pusher body  201 . Other suitable actuating mechanisms can be used with the drive member  150  of the invention to move staple pusher  126  and staple  124  a sufficient distance to drive staple  124  into the patient&#39;s tissue. For example, staple cartridge  122  may comprises another actuator, such as a rotational actuator, linear actuator, or a biasing mechanism, such as a spring-loaded actuator, that receives drive member  150  and advances staple pusher  126  vertically relative to the cartridge housing  250 . In the latter embodiment, the spring-loaded actuator will be configured to receive projections  228 ,  230  of drive member  150  and exert a spring force on pusher  126  to advance pusher  126  upwards relative to cartridge housing  250 . 
     As shown in  FIG.  4   , staple cartridge  122  preferably includes multiple staple assemblies  200  spaced from each other in the longitudinal direction. Thus as shown in the leftmost portion of  FIG.  5   , curved portion  208  will preferably have sufficient flexibility to allow elongate portion  210  to be moved beyond, or distal to, a substantially perpendicular orientation such that proximal end  212  of elongate portion  210  is moved vertically upwards a sufficient distance to provide clearance for drive member  150  to pass distally of each staple pusher  126  and engage the next staple assembly  200  in staple cartridge  122 . 
     Referring again to  FIG.  3   , in an exemplary embodiment, staple assembly  200  includes three staple pushers  126  and two drive rods  204  situated such that rods  204  are each coupled to two of the staple pushers  126 . In particular, curved portions  208  of drive rods  204  are each coupled to one of the outer staple pushers  126  and a central staple pusher  126 . Other suitable configurations may be utilized with the present invention. For example, drive rods  204  may be situated on the outside of stable assembly  200  such that they are each coupled to one of the outer staple pushers  126 . Alternatively, staple assembly  200  may comprise three drive rods  204  each coupled to only one staple pusher  126 . In yet another embodiment, staple assembly  200  includes only two staple pushers  126  with one drive rod  204  therebetween. Other suitable arrangements will be envisioned by those skilled in the art. 
     Referring now to  FIGS.  4  and  7   , a preferred embodiment of cartridge  122  will now be described. As shown, cartridge  122  includes an elongate housing  250  extending substantially along a longitudinal axis  251  and including a plurality of apertures or compartments  252  that form pockets  254  within the housing to receive staple assemblies  200 . As mentioned previously, staple assemblies  200  each include at least one (preferably 2-4) staple pushers  126  removably coupled to at least one (preferably 2-4) staples  124 . Staple assemblies  200  are preferably arranged within compartments  252  such that each staple pusher  126  is situated near a bottom surface of housing  250  and staples  124  have their legs facing a top surface of housing  250 . For ease of reference, the top surface of housing faces fixed jaw  111  (see  FIG.  1   ). As discussed above, the entire staple cartridge  122  can be loaded into movable jaw  112  for use in surgery as described in more detail below. 
     As shown in  FIG.  2 B , a preferred embodiment of drive member  150  includes a body  151  having a top surface  222 , a bottom surface  224  and a pair of side surfaces  226  connecting top and bottom surfaces  222 ,  224 . Drive member  150  further includes a pair of projections or shuttle fins  228 ,  230  extending laterally outward from side surfaces  226 . Shuttle fins  228 ,  230  preferably comprise substantially flattened appendages extending from either side of drive member  150 . Shuttle fins  228 ,  230  each include a distal end  232  configured to engage proximal ends  212  of drive rods  204  to drive pushers  126  (and the associated staples  124 ) vertically or perpendicular to the longitudinal axis when drive member  150  is translated in the distal direction. Distal ends  232  are preferably substantially perpendicular to the longitudinal axis of drive member  150 , although it will be recognized that ends  232  may define an incline, ramp, recess, pocket or other design and still fulfill the purpose of engaging proximal ends  212  of drive rods  204 . Shuttle fins  228 ,  230  are shown extending from the proximal portion of drive member body  151  with distal end  232  of each fin  228 ,  230  extending out from side surfaces  226 . However, it should be noted that shuttle fins  228 ,  230  may reside closer to the distal portion of drive member  150  than shown in  FIG.  2 B  so as to reduce the distance drive member  150  extends distally out from cartridge  122  after it has been moved to the final distal position (i.e., sufficiently far to engage all of the staple pushers  126  within cartridge  122 ). 
     Shuttle fins  228 ,  230  preferably extend laterally outward from body  151  a suitable distance to engage drive rods  204  (as best shown in  FIG.  4   ). Shuttle fins  228 ,  230  preferably have a substantially planar top surface  234  that is preferably located below top surface  222  of drive member body  151 . In the exemplary embodiment, shuttle fins  228 ,  230  have a height (as measured perpendicular to longitudinal axis  251 ) that is substantially less than the height of body  151 . In an exemplary embodiment, the height of shuttle fins  228 ,  230  are less than half of the height of body  151 , more preferably less than 25% of the height of body  151 . Fins  228 ,  230  preferably extend from the bottom portion of drive member body  151  to minimize the vertical footprint of fins  228 ,  230 . 
     In conventional drive members (see  FIGS.  6 A and  6 B ), the shuttle fins have an inclined distal surface or ramp  280  that extends almost all the way to the top surface of staple cartridge housing  250 . This ramp  280  is configured to engage the staple pushers and cam them upwards sufficiently far enough to drive the staples into tissue. To accommodate these shuttle fin ramps  280 , staple cartridge  122  typically includes a somewhat bulk nose  282  extending from its distal end that prevents ramps  280  of the drive member from contacting tissue when it reaches the most distal point of its translation through the end effector. The staple cartridge nose  282  increases the length of the surgical instrument and may inhibit access to certain areas of the surgical site. 
     In addition, staple cartridge  122  typically includes extensive cutouts through its elongate body to provide sufficient clearance for the passage of the drive member ramps.  FIG.  6 B  illustrates a conventional staple cartridge with a plurality of compartments for housing the staple pushers (not shown). As illustrated in  FIG.  6 B , the cartridge includes central support posts  288  completely surrounded by the cutouts to provide clearance for ramps  280 . These cutouts reduce the overall material strength of the staple cartridge; and they provide challenges and extra costs to the manufacturing process. 
     By contrast, shuttle fins  228 ,  230  of the present disclosure have a much smaller footprint than conventional “ramp shuttle fins”. As mentioned previously, they preferably extend to less than 50%, more preferably less than 25% of the height of the drive member  150 , which allows the designer to provide more material in staple cartridge  122  (i.e., less cutouts). In addition, the more compact shuttle fins  228 ,  230  of the present disclosure allow for a shorter and more compact nose at the distal end of shuttle cartridge, which reduces the overall size of surgical instrument  100 . In addition, having a more compact distal nose may allow the surgeon to access areas of the surgical site that would have been more difficult, or even impossible, with a larger and bulkier instrument. 
       FIG.  7    shows a portion of staple cartridge  122  that illustrates one of the advantages of the present invention. As shown, staple cartridge  122  generally includes an elongate housing  250  having a plurality of compartments  252  for housing staple assemblies  200 . As mentioned previously, the preferred embodiment of each staple assembly  200  includes three staple pushers (not shown) with one central staple pusher positioned just proximal to two lateral pushers. Accordingly, housing  250  includes pockets  254  for each of the staple pushers with a central support post  256  situated near each staple assembly (central support post  256  generally being located behind the central staple pusher and between the two lateral staple pusher within each staple assembly  200 ). In contrast to conventional designs, however, an exemplary cartridge  122  further includes a pair of diagonal support walls  258  coupling each central support post  256  with the rest of staple cartridge. Although not shown in  FIG.  7   , these diagonal support walls  258  do not extend all the way to the bottom surface of staple cartridge  122 . Instead, support walls  258  stop short of the bottom surface to provide clearance for shuttle fins  228 ,  230 . Diagonal support walls  258  provide additional strength to staple cartridge  122 . In addition, the overall staple cartridge is less expensive and easier to mold because it does not require the extensive cutouts typically used in conventional devices. 
     Referring again to  FIG.  2 B , shuttle fins  228 ,  230  are preferably integrated into the lower portion of drive member  150  such that the bottom surface of fins  228 ,  230  reside at approximately the same level as bottom surface  224  of drive member body  151 . This reduces the overall height and footprint take up by fins  228 ,  230 . In addition, integrating shuttle fins  228 ,  230  into drive member  150  provides more flexibility in the design of surgical instrument  100 . For example, this may allow for a reduction in the size of staple cartridge  122  and surgical instrument  100  and/or an increase in the length of staples  124  for a given size of surgical instrument  100 . 
     Referring now to  FIG.  8   , in certain embodiments, jaws  111 ,  112  are attached to surgical instrument  100  via a clevis  140 . Clevis  140  includes upper and lower portions that cooperate when assembled to form a protrusion  145  configured to engage tabs  113  (see  FIG.  1 A ) of jaw  111  to securely mount jaw  111  in a fixed position on instrument  100 . Clevis  140  further includes an opening for receiving a pivot pin  130  defining a pivot axis around which jaw  112  pivots as described in more detail below. A more complete description of a suitable clevis  140  for use with the present invention may be found in commonly-assigned, provisional patent application Nos. 62,783,444, filed Dec. 21, 2018; 62,783,481, filed Dec. 21, 2018; 62,783,460, filed Dec. 21, 2018; 62,747,912, filed Oct. 19, 2018; and 62,783,429, filed Dec. 21, 2018, the complete disclosures of which are hereby incorporated by reference in their entirety for all purposes. Of course, it will be recognized by those skilled in the art that other coupling mechanisms known by those skilled in the art may be used with the present invention to attach the jaws  11 ,  112  to the proximal portion of surgical instrument  100 . 
     End effector  110  may be articulated in multiple directions by an articulation mechanism. In certain embodiments, the articulation mechanism may be a wrist  160  as shown, although other articulation mechanisms are contemplated. As seen in  FIG.  8   , a preferred embodiment of wrist  160  includes a plurality of articulation joints  162 ,  164 ,  166 , etc. that define a bore  167  through which an actuation mechanism (in embodiments, coil  120  and drive cable  171 , see  FIGS.  9 A and  9 B ) may pass. Upon exiting articulation wrist  160 , coil  120  enters and passes through an internal channel (not shown) of clevis  140 , ultimately engaging proximal surface  153  of upper shoe  152  of drive member  150 . Other articulation mechanisms known by those skilled in the art may substitute for wrist  160 . Other exemplary articulating mechanisms are shown for example in U.S. Publication. No. 2015/0250530 the entire disclosure of which is hereby incorporated by reference in its entirety for all purposes. 
     As seen in  FIGS.  9 A and  9 B , an illustrative actuation assembly includes a drive cable  171 , a coil  120 , a sheath  121  surrounding coil  120 , and a drive rod  175 . Drive cable  171  includes an enlarged distal end  173 . Upper shoe  152  of drive member  150  includes a bore  158  (see also  FIG.  10   ) into which drive cables  171  are routed. When assembling illustrative surgical instrument  100 , coil  120  and a protective sheath  121  are slipped over the free end of drive cable  171 . The free end of drive cable  171  is attached to a drive rod  175  securing coil  120  and the protective sheath  121  between drive member  150  and drive rod  175 . Sheath  121  may function to promote stability, smooth movement, and prevent buckling upon actuation of surgical instrument  100 . Sheath  121  may be made from polyimide, or any other suitable material having the requisite strength requirements such as various reinforced plastics, a nickel titanium alloy such as NITINOL™, poly para-phenyleneterphtalamide materials such as KEVLAR™ commercially available from DuPont. Those of skill in the art may envision other suitable materials. 
     Enlarged distal end  173  of drive cable  171  resides within an enlarged distal portion  159  of bore  158  in upper shoe  152  of body  150 , such that the proximal face  157  of enlarged distal end  173  may apply a retraction force on upper shoe  152  when the drive cable  171  is pulled proximally. Drive rod  175  is operationally connected to an actuator which allows distal translation and proximal retraction of the actuation assembly. Those skilled in the art will recognize that in a manually actuated instrument, the actuator may be a movable handle, such as moveable handle  102   b  shown in  FIG.  1   ; in a powered instrument the actuator may be a button (not shown) that causes a motor to act on the drive rod; and in a robotic system, the actuator may be a control device such as the control devices described below in connection with  FIGS.  11  and  12   . 
     During actuation of illustrative surgical instrument  100 , drive rod  175  applies force to coil  120 , thereby causing coil  120  to apply force to upper shoe  152  of drive member  150 , translating it distally initially closing jaws  111 ,  112  and then ejecting staples  124  from cartridge  122  to staple tissue. After stapling is complete, drive rod  175  applies a force in the proximal direction to effect retraction of drive member. During retraction, enlarged distal end  173  of drive cable  171  is obstructed by wall  157  of enlarged portion  159  of bore  158 , causing drive cable  171  to apply force to upper shoe  152  of drive member  150 , thereby translating drive member  150  in the proximal direction. One of ordinary skill in the art will appreciate that drive member  150 , drive cable  171 , and drive rod  175  all move in unison and remain in the same relative position to each other. 
     Referring now to  FIG.  10   , in use, drive member  150  is positioned proximally of cam surface  114  formed on movable jaw  112 . As drive member  150  translates in the distal direction, movable jaw  112  will rotate towards the closed position around a pivot pin  130  (see, for example,  FIGS.  1 A and  1 D ). Once drive member  150  has come into contact with cam surface  114  of movable jaw  112 , lower portion  154  of drive member  150  rides underneath cam surface  114 , drive member  150  pushes movable jaw  112 , causing it to pivot towards the closed position. In the closed position, drive member  150  has translated distally past cam surface  114 . In this position, tissue is clamped, and further advancement of the drive member will sever and staple tissue. 
       FIG.  11    illustrates, as an example, a top view of an operating room employing a robotic surgical system. The robotic surgical system in this case is a robotic surgical system  300  including a Console (“C”) utilized by a Surgeon (“S”) while performing a minimally invasive diagnostic or surgical procedure, usually with assistance from one or more Assistants (“A”), on a Patient (“P”) who is lying down on an Operating table (“O”). 
     The Console includes a monitor  304  for displaying an image of a surgical site to the Surgeon, left and right manipulatable control devices  308  and  309 , a foot pedal  305 , and a processor  302 . The control devices  308  and  309  may include any one or more of a variety of input devices such as joysticks, gloves, trigger-guns, hand-operated controllers, or the like. The processor  302  may be a dedicated computer that may be integrated into the Console or positioned next to it. 
     The Surgeon performs a minimally invasive surgical procedure by manipulating the control devices  308  and  309  (also referred to herein as “master manipulators”) so that the processor  302  causes their respectively associated robotic arm assemblies,  328  and  329 , (also referred to herein as “slave manipulators”) to manipulate their respective removably coupled surgical instruments  338  and  339  (also referred to herein as “tools”) accordingly, while the Surgeon views the surgical site in 3-D on the Console monitor  304  as it is captured by a stereoscopic endoscope  340 . 
     Each of the tools  338  and  339 , as well as the endoscope  340 , may be inserted through a cannula or other tool guide (not shown) into the Patient so as to extend down to the surgical site through a corresponding minimally invasive incision such as incision  366 . Each of the robotic arms is conventionally formed of links, such as link  362 , which are coupled together and manipulated through motor controlled or active joints, such as joint  363 . 
     The number of surgical tools used at one time and consequently, the number of robotic arms being used in the system  300  will generally depend on the diagnostic or surgical procedure and the space constraints within the operating room, among other factors. If it is necessary to change one or more of the tools being used during a procedure, the Assistant may remove the tool no longer being used from its robotic arm, and replace it with another tool  331  from a Tray (“T”) in the operating room. 
     The monitor  304  may be positioned near the Surgeon&#39;s hands so that it will display a projected image that is oriented so that the Surgeon feels that he or she is actually looking directly down onto the operating site. To that end, images of the tools  338  and  339  may appear to be located substantially where the Surgeon&#39;s hands are located. 
     The processor  302  performs various functions in the system  300 . One important function that it performs is to translate and transfer the mechanical motion of control devices  308  and  309  to their respective robotic arms  328  and  329  through control signals over bus  310  so that the Surgeon can effectively manipulate their respective tools  338  and  339 . Another important function is to implement various control system processes as described herein. 
     Although described as a processor, it is to be appreciated that the processor  302  may be implemented in practice by any combination of hardware, software and firmware. Also, its functions as described herein may be performed by one unit, or divided up among different components, each of which may be implemented in turn by any combination of hardware, software and firmware. For additional details on robotic surgical systems, see, e.g., commonly owned U.S. Pat. No. 6,493,608 “Aspects of a Control System of a Minimally Invasive Surgical Apparatus,” and commonly owned U.S. Pat. No. 6,671,581 “Camera Referenced Control in a Minimally Invasive Surgical Apparatus,” which are hereby incorporated herein by reference in their entirety for all purposes. 
       FIG.  12    illustrates, as an example, a side view of a simplified (not necessarily in proportion or complete) illustrative robotic arm assembly  400  (which is representative of robotic arm assemblies  328  and  329 ) holding a surgical instrument  450  (which is representative of tools  338  and  339 ) for performing a surgical procedure. The surgical instrument  450  is removably held in tool holder  440 . The arm assembly  400  is mechanically supported by a base  401 , which may be part of a patient-side movable cart or affixed to the operating table or ceiling. It includes links  402  and  403 , which are coupled together and to the base  401  through setup joints  404  and  405 . 
     The setup joints  404  and  405  in this example are passive joints that allow manual positioning of the arm  400  when their brakes are released. For example, setup joint  404  allows link  402  to be manually rotated about axis  406 , and setup joint  405  allows link  403  to be manually rotated about axis  407 . Although only two links and two setup joints are shown in this example, more or less of each may be used as appropriate in this and other robotic arm assemblies in conjunction with the present invention. For example, although setup joints  404  and  405  are useful for horizontal positioning of the arm  400 , additional setup joints may be included and useful for limited vertical and angular positioning of the arm  400 . For major vertical positioning of the arm  400 , however, the arm  400  may also be slidably moved along the vertical axis of the base  401  and locked in position. 
     The robotic arm assembly  400  also includes three active joints driven by motors. A yaw joint  410  allows arm section  430  to rotate around an axis  461 , and a pitch joint  420  allows arm section  430  to rotate about an axis perpendicular to that of axis  461  and orthogonal to the plane of the drawing. The arm section  430  is configured so that sections  431  and  432  are always parallel to each other as the pitch joint  420  is rotated by its motor. As a consequence, the instrument  450  may be controllably moved by driving the yaw and pitch motors so as to pivot about the pivot point  462 , which is generally located through manual positioning of the setup joints  404  and  405  so as to be at the point of incision into the patient. In addition, an insertion gear  445  may be coupled to a linear drive mechanism (not shown) to extend or retract the instrument  450  along its axis  463 . 
     Although each of the yaw, pitch and insertion joints or gears,  410 ,  420  and  445 , is controlled by an individual joint or gear controller, the three controllers are controlled by a common master/slave control system so that the robotic arm assembly  400  (also referred to herein as a “slave manipulator”) may be controlled through user (e.g., surgeon) manipulation of its associated master manipulator. A more complete description of illustrative robotic surgical systems for use with the present invention can be found in commonly-assigned U.S. Pat. Nos. 9,295,524, 9,339,344, 9,358,074, and 9,452,019, the complete disclosures of which are hereby incorporated by reference in their entirety for all purposes. 
     Hereby, all issued patents, published patent applications, and non-patent publications that are mentioned in this specification are herein incorporated by reference in their entirety for all purposes, to the same extent as if each individual issued patent, published patent application, or non-patent publication were specifically and individually indicated to be incorporated by reference. 
     While several embodiments have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of presently disclosed embodiments. Thus, the scope of the embodiments should be determined by the appended claims and their legal equivalents, rather than by the examples given. 
     Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications and variances. As well, one skilled in the art will appreciate further features and advantages of the present disclosure based on the above-described embodiments. Accordingly, the present disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 
     Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the embodiment disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the embodiment being indicated by the following claims.