Abstract:
A surgical device includes a loading unit having proximal and distal portions. The proximal portion of the loading unit is configured to be attached to an actuation apparatus. The surgical device further includes a flexible shaft interconnecting the proximal portion and the distal portion of the loading unit. Additionally, the surgical device has a tool assembly disposed in mechanical cooperation with the distal portion of the loading unit. The tool assembly is configured to articulate upon activation of the actuation apparatus.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 60/997,812, filed Oct. 5, 2007, the entire disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to apparatus and methods for fastening tissue. More particularly, the present disclosure relates to a surgical stapling apparatus having a loading unit capable of applying surgical staples to tissue. 
     2. Description of Related Art 
     Surgical instruments for fastening tissue are well known. Some surgical fastening instruments have a tool assembly including opposing jaw structures for grasping tissue. These instruments often include a knife for incising the fastened tissue. The knife is usually positioned in one of the opposing jaw structures. At least one of the opposing jaw structures contains fasteners. These fasteners can be surgical staples or two-part fasteners. 
     Typically, the tool assembly includes a staple cartridge and an anvil. The staple cartridge houses a plurality of staples arranged in at least two laterally spaced rows, whereas the anvil usually includes a plurality of staple forming pockets for receiving the legs of the staples. The staple forming pockets of the anvil deform the staple legs as the staples are driven from the cartridge. A drive member located within the cartridge drives staples toward the anvil. 
     During the stapling operation, the drive member advances cam wedges longitudinally through the staple cartridge. The cam wedges act upon staple pushers to sequentially eject the staples from the staple cartridge. A knife may travel between the staple rows to longitudinally cut the stapled tissue between the rows of staples. 
     The described stapling process is frequently performed during minimally invasive surgical procedures, such as laparoscopic and endoscopic procedures. In laparoscopic and endoscopic procedures, healthcare professionals perform surgical procedures through a small incision or cannula inserted through a small entrance wound in a patient. To address the specific needs of endoscopic and laparoscopic surgical procedures, medical devices manufacturers have developed endoscopic surgical stapling instruments specifically suited to facilitate access to an operative site. Some endoscopic surgical stapling instruments include an articulatable tool assembly disposed on the distal end of the surgical stapling instrument. These surgical stapling instruments normally include an actuation apparatus to control the articulation of the tool assembly. U.S. Patent Application Serial No. 2007/0084898, which is hereby incorporated by reference in its entirety, describes a surgical stapling apparatus with an articulatable tool assembly. 
     SUMMARY 
     A surgical device includes a loading unit having proximal and distal portions. The proximal portion of the loading unit is configured to be attached to an actuation apparatus. The surgical device further includes a flexible shaft interconnecting the proximal portion and the distal portion of the loading unit. Additionally, the surgical device has a tool assembly disposed in mechanical cooperation with the distal portion of the loading unit. The tool assembly is configured to articulate upon activation of the actuation apparatus. In one embodiment, the tool assembly includes an anvil assembly and a cartridge assembly. The anvil assembly is configured to move relative to the cartridge assembly upon activation of the actuation apparatus. The surgical device may further include a center rod extending through the flexible shaft and at least a section of the proximal portion of the loading unit. The center rod is operatively associated with the tool assembly. Additionally, the surgical device may have a flexible articulation rod extending alongside the flexible shaft and through at least a section of the proximal portion of the loading unit. The flexible articulation rod is operatively associated with the tool assembly. The proximal portion of the loading unit may include a housing encompassing at least a portion of the center rod and at least a portion of the flexible articulation rod. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the presently disclosed surgical stapling instrument are described herein with reference to the drawings: 
         FIG. 1  is a perspective view of a loading unit of a surgical stapling instrument in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a perspective view of a surgical stapling instrument according to an embodiment of the present disclosure; 
         FIG. 3  is a perspective view of a distal portion of the loading unit of  FIG. 1 ; 
         FIG. 4  is a perspective view of a proximal portion of the loading unit of  FIG. 1 ; 
         FIG. 5  is a perspective view of the flexible articulation rod, the flexible center rod, the flexible shaft, and the distal portion of the loading unit of  FIG. 1 ; 
         FIG. 6  is a perspective sectional view of the flexible center rod, the flexible articulation rod, and the flexible shaft of the loading unit of  FIG. 1  taken around section  6  of  FIG. 5 ; 
         FIG. 7  is a perspective view of the distal portion of the loading unit of  FIG. 1 ; 
         FIG. 8  is a perspective view of an axial drive assembly according to an embodiment of the present disclosure; 
         FIG. 9  is a perspective view of the proximal portion of the loading unit of  FIG. 1 ; 
         FIG. 10  is a perspective view of the proximal portion of the loading unit of  FIG. 1  without the cover; 
         FIG. 11  is a perspective cross-sectional view of the proximal portion of the loading unit of  FIG. 1  taken along section line  11 - 11  of  FIG. 10 ; 
         FIG. 12  is a cross-sectional side view of the proximal portion of the loading unit of  FIG. 1  taken along section line  12 - 12  of  FIG. 4 ; 
         FIG. 13  is a cross-sectional side view of the distal portion of the loading unit of  FIG. 1  taken along section line  13 - 13  of  FIG. 3 ; 
         FIG. 14  is a cross-sectional top view of the proximal portion of the loading unit of  FIG. 1  taken along section line  14 - 14  of  FIG. 12 ; 
         FIG. 15  is a cross-sectional top view of the distal portion of the loading unit of  FIG. 1  taken along section line  15 - 15  of  FIG. 13 ; 
         FIG. 16  is a perspective view of the proximal portion of the loading unit of  FIG. 1  without the cover; 
         FIG. 17  is cross-sectional side view of the proximal portion of the loading unit of  FIG. 1 ; 
         FIG. 18  is a cross-sectional side view of the distal portion of the loading unit of  FIG. 1  with a tool assembly in a clamped position; 
         FIG. 19  is a cross-sectional top view of the proximal portion of the loading unit of  FIG. 1 ; and 
         FIG. 20  is a cross-sectional top view of the distal portion of the loading unit of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the presently disclosed surgical stapling instrument will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. In the description that follows, the term “proximal,” as is traditional, will refer to the end of the surgical stapling instrument that is closest to the operator, while the term “distal” will refer to the end of the instrument that is farthest from the operator. 
     With reference to  FIGS. 1 and 2 , an embodiment of a loading unit of a surgical stapling instrument is generally shown as  100 . Loading unit  100  may be, among other things, a single loading unit (“SULU”) or a disposable loading unit (“DLU”) and includes a proximal portion  102  and a distal portion  104 . A flexible shaft  107  interconnects proximal portion  102  and distal portion  104 . Distal portion  104  of loading unit  100  has a tool assembly  106  adapted to apply fasteners to tissue. Proximal portion  102  of loading unit  100  is configured to be releasably secured to any suitable actuation apparatus capable of actuating tool assembly  106 . 
     In the embodiment depicted in  FIG. 2 , a handle assembly  200  (shown in phantom) functions as an actuation apparatus. Handle assembly  200  includes a stationary handle  202 , a movable handle  204 , a barrel portion  206 , and an elongate body  208 . During operation, movable handle  204  moves relative to stationary handle  202 . The motion of movable handle  204  actuates tool assembly  106 . In addition to movable handle  204 , handle assembly  200  has a rotatable member  210  operatively coupled to elongate body  208 , such that the rotation of rotatable member  210  causes the corresponding rotation of elongate body  208 . Rotatable member  210  is rotatably mounted to barrel portion  206 . Barrel portion  206  also supports a pair of retraction knobs  212  configured to move therealong. The proximal translation of retraction knobs  212  moves tool assembly  106  from an actuated position to a retracted position, as described in detail in U.S. Patent Application Serial No. 2007/0084898, the entire contents of which is hereby incorporated by reference. Handle assembly  200  may further include an articulation lever (not shown) adapted to articulate tool assembly  106 . Although the drawings show handle assembly  200 , one skilled in the art will recognize that loading unit  100  may be used in conjunction with any suitable actuation apparatus capable of actuating and articulating the tool assembly  106  positioned on distal portion  104  of loading unit  100 . 
     Referring to  FIG. 3 , distal portion  104  of loading unit  100  includes a proximal body  108  and tool assembly  106 . Proximal body  108  supports a distal end  107   b  of flexible shaft  107 . A pivot member  110  pivotably connects proximal body  108  and tool assembly  106 . Tool assembly  106  contains a cartridge assembly  112  and an anvil assembly  114 . Cartridge assembly  112  houses a plurality of fasteners, such as staples. Anvil assembly  114 , in turn, is movable in relation to cartridge assembly  112  between an open position and a clamped position. In the open position, anvil assembly  114  is spaced apart from cartridge assembly  112 , as seen in  FIG. 13 . In the clamped position, anvil assembly  114  is in juxtaposed alignment with cartridge assembly  112 , as shown in  FIG. 18 . Additionally, cartridge assembly  112  includes retention slots  116  adapted to receive fasteners. In one embodiment, retention slots  116  are arranged in longitudinal rows. A channel  118  adapted to receive a cutting tool may be disposed between two longitudinal rows of retention slots  116 . In operation, the cutting tool moves along channel  118  in response to the actuation of an actuation apparatus, such as handle assembly  200 . 
     With reference to  FIGS. 4 ,  9 ,  10 ,  11 ,  12  and  14 , the proximal portion  102  of loading unit  100  is releasably secured to an actuation apparatus, as previously discussed. In particular, proximal portion  102  includes an engagement section  120  disposed at a proximal end  102   a  thereof. Engagement section  120  has engagement lugs  122  for releasably engaging a portion of an actuation apparatus in a bayonet coupling type fashion, as illustrated in  FIG. 12 . Besides engagement lugs  122 , engagement section  120  includes an insertion tip  124  for facilitating insertion of engagement section  120  into a portion of an actuation apparatus and a slit  140  for receiving an articulation component  142 . Slit  140  extends along the length of engagement section  120 . Articulation component  142 , which is slidably disposed in slit  140 , may be operatively associated with any suitable articulation mechanism of an actuation apparatus. Another portion of the actuation apparatus may be inserted through a lumen  144  defined in engagement section  120 . Lumen  144  extends through the length of engagement section  120  and is adapted to receive a portion of an actuation apparatus, such as an actuation shaft  214 , as seen in  FIG. 12 . Since loading unit  100  is designed to work in conjunction with several types of actuation apparatus, engagement section  120  may have other elements suitable to engage other kinds of actuation apparatus. 
     Proximal portion  102  of loading unit  100  further includes an elongate member  126  connected to engagement section  120 . Elongate member  126  includes a housing  128  and a cover  130 . Housing  128  has engagement protrusions  132  adapted to engage cover  130 . Cover  130  is detachably connected to housing  128 . Housing  128  and cover  130  together form a first bore  134 , a second bore  136 , and a slot  138 . Slot  138  extends along a proximal segment  146  and is disposed in communication with slit  140 . A portion of articulation component  142  is slidably positioned in slot  138 . 
     Second bore  136  is disposed in communication with slot  138  and is adapted to slidably receive a portion of articulation component  142 . A flexible articulation rod  148  is operatively coupled to articulation component  142 . In one embodiment, articulation component  142  includes an attaching portion  150  having a longitudinal opening  152 . Longitudinal opening  152  is configured for supporting a portion of flexible articulation rod  148 . A section of flexible articulation rod  148  is slidably disposed in second bore  136 . Second bore  136  extends through elongate member  126  and is adapted to slidably receive at least a portion of articulation component  142  and flexible articulation rod  148 . 
     First bore  134  also extends through elongate member  126 . A locking member  154  is slidably positioned in a portion of first bore  134 . Therefore, first bore  134  is adapted to slidably receive locking member  154 . Locking member  154  is configured to hold a portion of an actuation apparatus. In an embodiment, locking member  154  holds a distal protrusion  216  of actuation shaft  214 , as seen in  FIGS. 10 and 12 . The locking member  154  of the depicted embodiment has an oblong body  156  including a longitudinal flange  158 , a longitudinal hole  160 , and a locking portion  162 . Locking portion  162  is positioned at the proximal end  164  of oblong body  156  and includes a pair of legs  166 . Legs  166  define a recess  168  therebetween. Each leg  166  has an elongated retaining protrusion  166   a  having a tapered end. In the depicted embodiment, distal protrusion  216  of actuation shaft  214  fits into recess  168  of locking portion  162 . To connect distal protrusion  216  to locking member  154 , a user simply has to press distal protrusion  216  against locking member  154 . The pressure exerted by the user eventually forces distal protrusion  216  of actuation shaft  214  into recess  168  of locking member  154 . 
     As previously discussed, locking member  154  additionally includes a longitudinal flange  158 . Longitudinal flange  158  protrudes from a periphery of oblong body  156  and is adapted to slidably fit into a groove  170  of housing  128 . Groove  170  extends along an inner surface of housing  128  and is longitudinally aligned with first bore  134 . 
     Aside from longitudinal flange  158 , locking member  154  has a longitudinal hole  160  configured to receive a flexible center rod  172 . Specifically, longitudinal hole  160  supports a proximal end  172   a  of flexible center rod  172 . Flexible center rod  172  is slidably disposed in first bore  134 . Therefore, first bore  134  slidably receives at least a portion of locking member  154  and flexible center rod  172 . In addition, first bore  134  is disposed in communication with lumen  144  of engagement section  120  and extends through elongate member  126 . 
     Elongate member  126  further includes an insertion portion  174  positioned at a distal end thereof. In particular, housing  128  and cover  130  of elongate member  126  together form insertion portion  174 . Insertion portion  174  facilitates insertion of elongate member  126  into a coupling  176 . Coupling  176  connects elongate member  126  and flexible shaft  107 . In an embodiment, coupling  176  includes a bore  178  extending therethrough. Bore  178  of coupling  176  is designed to receive insertion portion  174  of elongate member  126 , a proximal end  107   a  of flexible shaft  107 , and a portion of flexible articulation rod  148 . 
     With reference to  FIGS. 5 and 6 , flexible articulation rod  148  is disposed alongside flexible shaft  107 . In the depicted embodiment, a holding member  180 , such as shrink wrap, holds flexible shaft  107  and flexible articulation rod  148  together. Flexible shaft  107  includes a central lumen  182  configured to receive center rod  172 . Thus, flexible shaft  107  surrounds at least a portion of flexible center rod  172 . Distal portion  104  of loading unit  100  supports a distal end  107   b  of flexible shaft  107 . 
     With reference to  FIGS. 7 ,  8 ,  13 , and  15 , proximal body  108  of distal portion  104  includes a central bore  184  configured to receive, among other things, distal end  107   b  of flexible shaft  107 . Central bore  184  extends through proximal body  108  and encompasses a coupling member  186 , as seen in  FIG. 13 . Coupling member  186  couples an axial drive assembly  188  to flexible shaft  107  and flexible articulation rod  148 . Axial drive assembly  188  has an adapter  190  mounted to its proximal end  188   a . Adapter  190  facilitates the interconnection between axial drive assembly  188  and flexible center rod  172 . In one embodiment, adapter  190  of axial drive assembly  188  includes a hole  192  adapted to receive flexible center rod  172 . 
     In addition to adapter  190 , axial drive assembly  188  includes an elongate drive beam  194  having a distal working head  196 . (See  FIG. 8 .) Drive beam  194  may be constructed from a single sheet material or from multiple stacked sheets. Distal working head  196  has a retention flange  199  and a support strut  197 . Retention flange  199  supports at least one cam roller  195  at its distal end. In the embodiment shown in  FIG. 8 , retention flange  199  supports two cam rollers  195  positioned transversely with respect to retention flange  199 . Cam rollers  195  are slidably engaged to anvil assembly  114  such that when axial drive assembly  188  is translated distally, anvil assembly  114  moves from the open position to the clamped position, as depicted in  FIG. 18 . Support strut  197  has an abutment surface  191  that engages a central portion of an actuation sled  189 . In an alternate embodiment, support strut  197  supports a cutting tool. As seen in  FIG. 13 , support strut  197 , which is slidably positioned within cartridge assembly  112 , also includes a base  187  adapted to engage a support member  185 . Support member  185  of distal working head  196  is located on a lower portion of cartridge assembly  112 . In general, the distal working head  193  of elongate drive beam  194  is positioned within cartridge assembly  112 . Another portion of elongate drive beam  194 , however, is slidably located in central bore  184  of proximal body  108 . Proximal body  108  also houses a pair of blow out plates  183  positioned on elongate drive beam  194  of axial drive assembly  188 . Blow out plates  183  dampen the bulging of axial drive assembly  188  during articulation and firing of tool assembly  106 . 
     Proximal body  108  also surrounds a portion of flexible articulation rod  148 . A distal end  148   b  of flexible articulation rod  148  is operatively connected to a proximal end  181   a  of an articulation link  181 . A distal end  181   b  of articulation link  181  is operatively coupled to a projection  179  located on a proximal portion of cartridge assembly  112 . Projection  179  is laterally offset from pivot member  110 , such that the longitudinal movement of articulation link  181  causes the articulation of tool assembly  106 , as described in detail below. 
     In one embodiment, pivot member  110  has a connecting member  177  and a pivot pin  175 . Connecting member  177  includes an interlocking proximal portion  173  for facilitating connection between proximal body  108  and tool assembly  106 . A distal portion of connecting member  177  includes an opening  175   a  adapted to receive pivot pin  175 . Although the drawings show a specific kind of pivot member  110 , one skilled in the art will envision that any suitable apparatus may pivotably connect proximal body  108  to tool assembly  106 . 
     As discussed hereinabove, tool assembly  106  includes anvil assembly  114  and cartridge assembly  112 . Anvil assembly  114 , which is configured to move relative to cartridge assembly  112 , has a tissue contacting surface  171 . Tissue contacting surface  171  includes fastener forming concavities (not shown) adapted to deform fasteners when driven towards anvil assembly  114  from cartridge assembly  112 . Cartridge assembly  112  also has a tissue contacting surface  169 . Retention slots  116  are arranged in longitudinal rows on tissue contacting surface  169 . In the depicted embodiment, cartridge assembly  112  has six longitudinal rows of retentions slots  116 . Retention slots  116  also retain pushers (not shown). In operation, actuation sled  189  interacts with pushers to eject the fasteners housed in retention slots  116 . 
     Actuation sled  189  includes at least one cam wedge  167  and is operatively secured to axial drive assembly  188 . During firing of tool assembly  106 , actuation sled  189  translates through cartridge assembly  112  to advance cam wedges  167  into sequential or simultaneous contact with the pushers. When cam wedges  167  contact the pushers, the pushers translate vertically within retention slots  116  and urge the fasteners from retention slots  116  into the fastener deforming concavities of anvil assembly  114 . 
     Referring now to  FIGS. 16-20 , before initiating the stapling operation, user should first secure loading unit  100  to a suitable apparatus, such as apparatus  200 . In the case of actuation apparatus  200 , users may connect actuation apparatus  200  to proximal portion  102  of loading unit  100  by advancing actuation shaft  214  in the direction indicated by arrow “A” until distal protrusion  216  engages legs  166  of locking member  154 . Before or after properly connecting an actuation apparatus to proximal portion  102 , the user may insert loading unit  100  through a cannula or an incision in a patient. While inserting loading unit  100  into a patient, the user may bend flexible shaft  107  to reach the target surgical site. Also, the user may articulate tool assembly  106  to place it in the desired location. To articulate tool assembly  106 , the user should activate the articulation mechanism of the connected actuation apparatus. As the articulation mechanism is triggered, articulation component  142  moves in a proximal or distal direction through slit  140 . If the user moves articulation component  142  distally, as indicated by arrows “B” in  FIG. 19 , articulation rod  148  moves distally, as indicated by arrow “C.” The distal translation of articulation rod  148  causes the corresponding distal advancement of articulation link  181  in the direction indicated by arrow “D.” As articulation link  181  is advanced distally, tool assembly  106  pivots about pivot member  110  in the direction indicated by arrow “E.” To articulate tool assembly  106  in an opposite direction, the user should move articulation component  142  in a proximal direction. 
     After placing tool assembly  106  in the target position, the user may fire tool assembly  106  to fasten tissue. The user may fire tool assembly  106  by triggering an actuation apparatus properly connected to loading unit  100 . When the connected actuation apparatus is triggered, locking member  154  moves distally through first bore  134  of proximal portion  102 . The distal translation of locking member  154  causes the corresponding distal movement of flexible center rod  172 , as indicated by arrows “F.” As flexible center rod  172  moves distally, axial drive assembly  188  advances distally in the direction indicated by arrows “G.” While axial drive assembly  188  moves distally, cam rollers  195  slide through anvil assembly  114  and move anvil assembly  114  from an open position, as illustrated in  FIG. 13 , to a clamped position, as depicted in  FIG. 18 . When anvil assembly  114  moves to its clamped position, it pivots in the direction indicated by arrow “H” in  FIG. 18 . 
     The distal advancement of axial drive assembly  188  also causes the corresponding distal movement of actuation sled  189  in the direction indicated by arrow “I.” As actuation sled  189  translates through cartridge assembly  112 , cam wedges  167  advance and sequentially or simultaneously contact the pushers. When cam wedges  167  contact the pushers, the pushers translate vertically within retention slots  116  and urge the fasteners from retention slots  116  into the fastener deforming concavities of anvil assembly  114 . 
     It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure.