Abstract:
A loading unit configured for engagement with a surgical instrument is disclosed. The loading unit comprises a proximal body portion and a tool assembly. The proximal body portion defines a longitudinal axis. The tool assembly is disposed in mechanical cooperation with the proximal body portion and includes a cartridge assembly and an anvil assembly. At least one of the cartridge assembly and the anvil assembly is movable with respect to the other between an open position and an approximated position to engage tissue therebetween. The cartridge assembly is configured to house a plurality of fasteners therein. The diameter of the tool assembly is less than or equal to about 8 mm.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation and claims the benefit of and priority to U.S. patent application Ser. No. 13/849,590, filed Mar. 25, 2013, the entire disclosure of which is incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    Technical Field 
         [0003]    The present disclosure relates generally to instruments for surgically joining tissue and, more specifically, to a surgical fastening instrument and a loading unit including an end effector having a relatively small diameter. 
         [0004]    Background of Related Art 
         [0005]    Various types of surgical instruments used to surgically join tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, anastomoses, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue. 
         [0006]    One example of such a surgical instrument is a surgical stapling instrument, which may include an anvil assembly, a cartridge assembly for supporting an array of surgical fasteners, an approximation mechanism for approximating the cartridge and anvil assemblies, and a firing mechanism for ejecting the surgical fasteners from the cartridge assembly. 
         [0007]    Using a surgical instrument, it is common for a surgeon to approximate the anvil and cartridge members. Next, the surgeon can fire the instrument to emplace fasteners in tissue. Additionally, the surgeon may use the same instrument or a separate instrument to cut the tissue adjacent or between the row(s) of fasteners. 
         [0008]    Additionally, a single use loading (“SULU”) or a disposable loading unit (“DLU”) may be attached to an elongated or endoscopic portion of a surgical stapling instrument. Such loading units allow surgical stapling instruments to have greater versatility, for example. The loading units may be configured for a single use, and/or may be configured to be used more than once. 
         [0009]    Further, end effectors and/or loading units are generally limited in size by various components contained therein. That is, while there may be a need for end effectors and/or loading units having diameters that are smaller than those typically available, the diameter of the end effector and/or loading unit is typically limited by the size, geometry and/or orientation of the staple pushers, I-beam, actuation sled, and fasteners, for example, contained therein. 
       SUMMARY 
       [0010]    The present disclosure relates to a loading unit configured for engagement with a surgical instrument. The loading unit comprises a proximal body portion and a tool assembly. The proximal body portion defines a longitudinal axis. The tool assembly is disposed in mechanical cooperation with the proximal body portion and includes a cartridge assembly and an anvil assembly. At least one of the cartridge assembly and the anvil assembly is movable with respect to the other between an open position and an approximated position to engage tissue therebetween. The cartridge assembly is configured to house a plurality of fasteners therein. The diameter of the tool assembly is less than or equal to about 8 mm. 
         [0011]    In disclosed embodiments, the diameter of the tool assembly is equal to about 7 mm. 
         [0012]    In disclosed embodiments, a diameter of a portion of the proximal body portion is substantially equal to the diameter of the tool assembly. 
         [0013]    In disclosed embodiments, the loading unit further comprises a clamping member disposed in mechanical cooperation with the cartridge assembly and the anvil assembly. Here, the clamping member includes a vertical portion defining a vertical axis and being substantially perpendicular to the longitudinal axis. It is further disclosed that the loading unit further comprises an actuation sled longitudinally translatable at least partially within the cartridge assembly. The actuation sled includes at least two camming surfaces: a first camming surface extends at a first angle with respect to a plane extending through the longitudinal axis and the vertical axis (the vertical axis is within the plane) and a second camming surface extends at a second angle with respect to the plane. It is further disclosed that first angle and the second angle are between about 15° and about 40°, or between about 20° and about 35°. It is further disclosed that the actuation sled includes a V-like profile. It is further disclosed that at least a majority of a first tissue-contacting surface of the cartridge assembly is disposed at a substantially perpendicular angle with respect to the first angle, and at least a majority of a second tissue-contacting surface of the cartridge assembly is a disposed at a substantially perpendicular angle with respect to the second angle. 
         [0014]    In disclosed embodiments, the cartridge assembly includes a plurality of fasteners therein. Each of the plurality of fasteners is configured to be ejected from the cartridge assembly at an angle that is neither parallel nor perpendicular to the vertical axis. 
         [0015]    In disclosed embodiments, the clamping member includes a top portion for engaging the anvil assembly and a bottom portion for engaging the cartridge assembly. A total height defined between an upper-most surface of the top portion and a lower-most surface of the bottom portion is between about 1 mm and about 2.5 mm, or about 2 mm. 
         [0016]    In disclosed embodiments, the loading unit further comprises an actuation sled longitudinally translatable at least partially within the cartridge assembly. The clamping member includes a top portion for engaging the anvil assembly and a bottom portion for engaging the cartridge assembly. A lower-most surface of the bottom portion is closer to the top portion of the clamping member than an upper-most surface of the actuation sled. 
         [0017]    The present disclosure also relates to a cartridge assembly for use with a tool assembly of a surgical instrument. The cartridge assembly comprises a plurality of fasteners disposed at least partially therein, and an actuation sled configured for longitudinal translation therein along a first longitudinal axis. Each of the plurality of fasteners is configured to be ejected at a non-perpendicular angle with respect to the first longitudinal axis. 
         [0018]    In disclosed embodiments, the actuation sled includes a V-like profile including a first camming surface disposed at a first angle and a second camming surface disposed at a second angle. It is further disclosed that the cartridge assembly comprises a first tissue-contacting surface and a second tissue-contacting surface. At least a majority of the first tissue contacting surface is disposed at a substantially perpendicular angle with respect to the first angle. At least a majority of the second tissue-contacting surface of the cartridge assembly is a disposed at a substantially perpendicular angle with respect to the second angle. 
         [0019]    The present disclosure also relates to a surgical instrument comprising a handle assembly, an elongated body portion extending distally from the handle assembly, and a loading unit configured for engagement with a distal end of the elongated body portion. The loading unit comprises a proximal body portion defining a longitudinal axis, and a tool assembly disposed in mechanical cooperation with the proximal body portion. The tool assembly includes a cartridge assembly and an anvil assembly. At least one of the cartridge assembly and the anvil assembly being movable with respect to the other between an open position and an approximated position to engage tissue therebetween. The cartridge assembly is configured to house a plurality of fasteners therein. The diameter of the tool assembly is less than or equal to about 8 mm. 
         [0020]    In disclosed embodiments, the surgical instrument further comprises a clamping member disposed in mechanical cooperation with the cartridge assembly and the anvil assembly. The clamping member includes a vertical portion defining a vertical axis and is substantially perpendicular to the longitudinal axis. 
         [0021]    In disclosed embodiments, the cartridge assembly includes a plurality of fasteners therein, and each of the plurality of fasteners is configured to be ejected from the cartridge assembly at an angle that is neither parallel nor perpendicular to the vertical axis. 
         [0022]    In disclosed embodiments, the surgical instrument includes an actuation sled longitudinally translatable at least partially within the cartridge assembly. The actuation sled includes at least two camming surfaces. A first camming surface extends at a first angle with respect to a plane extending through the longitudinal axis and the vertical axis (the vertical axis is within the plane), and a second camming surface extends at a second angle with respect to the plane. It is further disclosed that the first angle and the second angle are between about 15° and about 40°, or about 20° and about 35°. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0023]    Various embodiments of the presently disclosed surgical instruments and loading units are disclosed herein with reference to the drawings, wherein: 
           [0024]      FIG. 1  is a perspective view of a surgical instrument including a first handle assembly in accordance with an embodiment of the present disclosure; 
           [0025]      FIG. 2  is a perspective view of a surgical instrument including a second handle assembly in accordance with an embodiment of the present disclosure 
           [0026]      FIGS. 3 and 4  are perspective views of a loading unit in accordance with the present disclosure; 
           [0027]      FIG. 5  is a perspective view of the loading unit of  FIGS. 3 and 4  illustrating the end effector disposed in an articulated position; 
           [0028]      FIG. 6  is a radial cross-sectional view of a portion of the end effector taken through line  6 - 6  in  FIG. 2 ; 
           [0029]      FIG. 7  is a perspective view of various internal components of the loading unit of  FIGS. 3 and 4 ; 
           [0030]      FIG. 8  is a perspective view of the portion of the loading unit indicated in  FIG. 7 ; 
           [0031]      FIG. 9  is a perspective view of various internal components of the loading unit of  FIGS. 3 and 4 ; 
           [0032]      FIG. 10  is a perspective view of the portion of the loading unit indicated in  FIG. 8 ; 
           [0033]      FIG. 11  is an assembly view of a portion of the loading unit; 
           [0034]      FIG. 12  illustrates the portion of the loading unit indicated in  FIG. 11 ; 
           [0035]      FIG. 13  illustrates the portion of the loading unit indicated in  FIG. 11 ; 
           [0036]      FIG. 14  is a perspective view of a portion of the loading unit of the present disclosure; 
           [0037]      FIG. 15  illustrates the portion of the loading unit indicated in  FIG. 14 ; 
           [0038]      FIG. 16  is a longitudinal cut-away view of a portion of the loading unit as indicated along line  16 - 16  in  FIG. 8 ; 
           [0039]      FIG. 17  is a longitudinal cross-sectional view of a portion of the loading unit; and 
           [0040]      FIG. 18  illustrates the portion of the loading unit indicated in  FIG. 17 . 
       
    
    
     DETAILED DESCRIPTION 
       [0041]    Embodiments of the presently disclosed surgical instrument, loading unit for use therewith, and cartridge assembly for use therewith, are described in detail with reference to the drawings, wherein like reference numerals designate corresponding elements in each of the several views. As is common in the art, the term “proximal” refers to that part or component closer to the user or operator, e.g., surgeon or physician, while the term “distal” refers to that part or component farther away from the user. 
         [0042]    A surgical instrument of the present disclosure is indicated as reference numeral  100  in  FIGS. 1 and 2 . Generally, surgical instrument  100  includes a handle assembly  110 , an elongated body portion  120  extending distally from handle assembly  110 , and a loading unit  200  disposed adjacent a distal end of elongated body portion  120 .  FIG. 1  illustrates surgical instrument  100  including a first handle assembly  110  (e.g., a powered handle assembly), and  FIG. 2  illustrates surgical instrument  100  including a second handle assembly  110 . It is also envisioned that other types of handles can be used such as, for example, motor-driven, hydraulic, ratcheting, etc. As used herein, “handle assembly” encompasses all types of handle assemblies. Loading unit  200  is attachable to endoscopic portion  120  of surgical stapling instrument  100 , e.g., to allow surgical instrument  100  to have greater versatility. As used herein, “loading unit” encompasses both single use loading units (“SULU”) and disposable loading units (“DLU”). Additionally or alternatively, surgical instrument  100  may have a cartridge which is removable and replaceable in the reusable jaws of the instrument. 
         [0043]    Examples of loading units for use with a surgical stapling instrument are disclosed in commonly-owned U.S. Pat. No. 5,752,644 to Bolanos et al., the entire contents of which are hereby incorporated by reference herein. Further details of an endoscopic surgical stapling instrument are described in detail in commonly-owned U.S. Pat. No. 6,953,139 to Milliman et al., the entire contents of which are hereby incorporated by reference herein. 
         [0044]    In a surgical instrument  100  in accordance with the present disclosure, a firing rod is moved distally through actuation of handle assembly  110  to deploy fasteners  600 . With reference to the embodiment illustrated in  FIG. 1 , at least a partial actuation of switch  112  translates the firing rod longitudinally. With reference to the embodiment illustrated in  FIG. 2 , at least a partial actuation of a movable handle  132  with respect a stationary handle  134  translates the firing rod longitudinally. Translation of the firing rod causes translation of a knife bar  140  and translation of a sled bar  150  (see  FIGS. 17 and 18 , for example; with particular reference to  FIG. 18 , knife bar  140  includes a proximal section  140   a  and a distal section  140   b , which are linked together). Further, translation of knife bar  140  causes translation of a clamping member  500  to approximate at least one jaw member with respect to the other, and translation of sled bar  150  causes translation of an actuation sled  520  to cause fasteners  600  to be ejected from pockets  401  of a cartridge assembly  400 . 
         [0045]    With reference to  FIGS. 3-5 , loading unit  200  of the present disclosure is shown. Loading unit  200  includes a proximal body portion  210  defining a longitudinal axis “A-A,” and a tool assembly or end effector  220  including a pair of jaw members (i.e., an anvil assembly  300  and a cartridge assembly  400 ). Proximal body portion  210  is configured to removably attach to endoscopic portion  120  of surgical instrument  100 . More particularly, an insertion tip  202  of loading unit  200  is linearly inserted into the distal end of endoscopic portion  120  of surgical stapling instrument  100 . Nubs  204  of insertion tip  202  move linearly through slots formed adjacent the distal end of endoscopic portion  120 . Subsequently, loading unit  200  is rotated about the longitudinal axis “A-A” such that nubs  204  move transversely through the slots within endoscopic portion  120 . Additionally, during engagement of loading unit  200  and endoscopic portion  120 , the firing rod of handle portion  110  engages knife bar  140  of loading unit  200 . 
         [0046]    With reference to  FIG. 6 , clamping member  500  includes an I-shaped cross-section, including a top portion  502 , which is configured to engage anvil assembly  300 , a bottom portion  504 , which is configured to engage cartridge assembly  400 , and a vertical portion  503 , which connects top portion  502  and bottom portion  504  and which may include a cutting edge  506  on its distal surface. More particularly, engagement between bottom portion  504  of clamping member  500  and cartridge assembly  400  helps maintain the relative positions of anvil assembly  300  and cartridge assembly  400  with respect to each other. 
         [0047]    With further regard to actuation sled  520 , distal translation of actuation sled  520  sequentially engages a plurality of pushers  540 , and causes pushers  540  to move toward respective tissue-contacting surfaces  410  of cartridge assembly  400  and eject fasteners  600  towards anvil assembly  300 . Subsequent to the ejection of fasteners  600 , cutting edge  506  of clamping member  500  may be included on a distal face thereof to sever the stapled tissue. 
         [0048]    With reference to  FIGS. 6-18 , further details of loading unit  200  are illustrated. Generally, the features of loading unit  200  disclosed herein allow loading unit  200  to have a relatively small diameter (e.g., 7 mm-8 mm) as compared with instruments having diameters of about 12 mm. The diameter of the loading unit  200  is measured between a radially outer-most wall of anvil assembly  300  and a radially outer-most wall of cartridge assembly  400  (see  FIG. 6 ). Such a low profile allows loading unit  200  to be inserted into trocars having similar diameters. As can be appreciated, these low profile loading units  200  are useful in pediatric surgeries and/or other thin tissue locations, for example. Additionally, in the illustrated embodiments, a proximal portion  212  of proximal body portion  210  of loading unit  200  is sized and configured to engage an elongated portion of a surgical instrument having a larger-diameter elongated portion  120  (e.g., about 12 mm), thus enabling greater versatility. 
         [0049]    With specific reference to  FIG. 6 , a radial cross-section of loading unit  200  is shown from a distal end. As shown, pushers  540 , fasteners  600 , a tissue contacting surface  310  of anvil assembly  300 , and a tissue contacting surface  410  of cartridge assembly are disposed at a non-perpendicular angle with respect to a plane C-C ( FIG. 8 ). Plane C-C extends through longitudinal axis A-A and through a vertical axis B-B, defined by vertical portion  503  of clamping member  500 . Further, vertical axis B-B is within plane C-C. These non-perpendicular angles, and the relative low-profile of clamping member  500  (as compared to clamping members of larger (e.g., 12 mm) instruments), for example, help enable loading unit  200  to have a small diameter. It is envisioned that the total height of clamping member  500  is between about 1 mm and about 2.5 mm, or about 2 mm. 
         [0050]    With further reference to  FIG. 6  and with additional reference to  FIGS. 11-13 and 17-18 , further details of loading unit  200  are shown. With particular reference to  FIGS. 17 and 18 , a cross-section of loading unit  200  is shown and includes knife bar  140 , sled bar  150 , anvil assembly  300 , cartridge assembly  400 , clamping member  500  and actuation sled  520 . With particular reference to  FIGS. 6 and 12 , cartridge assembly  400  includes a cartridge  408  (including two halves) and a cartridge channel  409 . Cartridge  408  is disposed within cartridge channel  409 . 
         [0051]    In use, distal translation of the firing rod, as discussed above, forces knife bar  140  to translate distally. Further, distal translation of knife bar  140  causes a protrusion  143  (see  FIG. 17 ) of knife bar  140  to contact a proximal face  151  of sled bar  150 , which causes distal translation of sled bar  150 . As sled bar  150  moves distally, a distal face  152  of sled bar  150  contacts a camming surface  402  of cartridge assembly  400 , which causes cartridge assembly  400  to move toward anvil assembly  300 . Additionally, as knife bar  140  moves distally, top portion  502  of clamping member  500  is distally advanced within a slot  304  within anvil assembly  300 , and bottom portion  504  of clamping member  500  is distally advanced within a slot  414  within a cartridge channel  409  of cartridge assembly  400  to help stabilize the jaw members with respect to each other and to help maintain a constant gap between the jaw members. Thus, a predetermined amount of distal travel of the firing rod causes approximation and stabilization of jaw members. 
         [0052]    Continued advancement of the firing rod and thus knife bar  140 , causes continued advancement of sled bar  150  into a proximal face  522  of actuation sled  520 , and causes distal movement of actuation sled  520 . As actuation sled  520  advances distally, angled camming surfaces  524  thereof (see  FIGS. 6 and 12 ) contact camming surfaces of pushers  540 , thus causing pushers  540  to engage fasteners  600 , and subsequently cause ejection of fasteners  600  toward respective pockets  320  of anvil assembly  300  (e.g., through tissue held between the jaw members). As shown (e.g., in  FIG. 6 ), actuation sled  520  includes a substantially V-shaped profile. As shown (e.g., in  FIG. 12 ), each pusher  540  includes two, longitudinally-spaced fastener-contacting portions or pusher plates  544  interconnected by connectors  542 . Additionally, the continued advancement of the firing rod also causes continued advancement of knife bar  140  and clamping member  200  such that top portion  502  of clamping member  500  continues to travel within slot  304  of anvil assembly  300 , and bottom portion  504  of clamping member  500  continues to travel within slot  414  of cartridge channel  409 . Additionally, cutting edge  506  of clamping member  500 , if included on clamping member  500 , severs tissue disposed between the jaw members (and after the tissue has been fastened, as discussed above). The sled cams care desirably arranged to fire all four rows of staples at about the same time to seal the tissue on both sides of the knife slot just prior to the knife cutting the tissue. 
         [0053]    As shown, and as discussed above, various features of loading unit  200  are sized and oriented to enable a small diameter (e.g., 7 mm) of loading unit and jaw members. In particular, camming surfaces  524  of actuation sled  520 , pushers  540 , pockets  401 , and fasteners  600  are disposed at a first non-perpendicular angle (e.g., between about 15° and about 40°, or between about 20° and about 35°, with respect to the vertical axis B-B (which extends through the longitudinal axis A-A). Further, tissue contacting surfaces  310 ,  410  of anvil assembly  300  and cartridge assembly  400 , respectively, are disposed at a corresponding, second non-perpendicular angle such that tissue contacting surface  310  is substantially parallel to tissue contacting surface  410  along at least a majority of the entire lengths of each of the respective surfaces, and such that the first non-perpendicular angle and the second non-perpendicular are substantially perpendicular to each other (i.e., fasteners  600  are disposed at an angle that is substantially perpendicular to the angle of tissue contacting surface  310  of anvil  300 , for example). Additionally, clamping member  500  is disposed within the space formed by the angle between camming surfaces  524  of actuation sled  520 , and pushers  540  (see  FIG. 6 ). 
         [0054]    Referring now to  FIGS. 5, 7, 8, 11, 13 and 16 , the articulation mechanism of surgical instrument  100  is shown. The articulation mechanism enables end effector  220  of loading unit  200  to be able to pivot with respect to proximal body portion  210  (see  FIG. 5 ). Articulation mechanism includes an articulation lever  700  disposed adjacent elongated body portion  120  (see  FIGS. 1 and 2 ), an articulation link disposed in mechanical cooperation with articulation lever  700 , an articulation rod  710  engageable with the articulation link and extending through proximal body portion  210  of loading unit  200  and into engagement with an articulation pin  223  of a proximal portion  222  of end effector  220 , and a pivot assembly  720  disposed between proximal body portion  210  and end effector  220  of loading unit  200 . With particular reference to  FIG. 13 , pivot assembly  720  includes a link  722 , which pivotably couples a stabilizer  724  of proximal body portion  210  and a link pin  224  ( FIG. 16 ) of proximal portion  222  of end effector  220 . Additionally, a pair of clips  730  extends between proximal body portion  210  and end effector  220 . As shown in  FIG. 8 , knife bar  140  extends between clips  730 . In certain embodiments, the clips function as blowout plates, with the plates having ends that are fixed in the device. 
         [0055]    In use, rotation of articulation lever  700  in a first direction (e.g., counter-clockwise) causes distal movement of the articulation link and articulation rod  710 , thus causing end effector  220  to pivot in a first direction (e.g., arrow “C” in  FIG. 5 ) with respect to proximal body portion  210 ; rotation of articulation lever  700  in a second direction (e.g., clockwise) causes proximal movement of the articulation link and articulation rod  710 , thus causing end effector  200  to pivot in a second direction (e.g., opposite arrow “C”) with respect to proximal body portion  210 . 
         [0056]    The present disclosure also includes a method of using the surgical instrument  100 , loading unit  200  and/or cartridge assembly  400 , as discussed herein. 
         [0057]    While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the present disclosure, but merely as illustrations of various embodiments thereof. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.