Patent Publication Number: US-2013240597-A1

Title: Surgical Stapler

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/589,100 filed on Aug. 18, 2012, now U.S. Pat. No. ______, which is a continuation of U.S. patent application Ser. No. 12/819,408, filed on Jun. 21, 2010, now U.S. Pat. No. 8,267,301, which claims priority to, and the benefit of U.S. Provisional Patent Application Ser. No. 61/235,131, filed Aug. 19, 2009, the entire contents of each of these prior applications are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to a surgical stapling device for applying surgical staples to body tissue. More particularly, the present disclosure relates to a surgical stapling device suitable for performing circular anastomosis and/or treatment to internal walls of hollow tissue organs. 
     2. Background of Related Art 
     Anastomosis is the surgical joining of separate hollow organ sections. Typically, an anastomosis procedure follows surgery in which a diseased or defective section of hollow tissue is removed and the remaining end sections are to be joined. Depending on the desired anastomosis procedure, the end sections may be joined by either circular, end-to-end or side-to-side organ reconstruction methods. 
     In a circular anastomosis procedure, the two ends of the organ sections are joined by means of a stapling instrument which drives a circular array of staples through the end section of each organ section and simultaneously cores any tissue interior of the driven circular array of staples to free the tubular passage. Examples of instruments for performing circular anastomosis of hollow organs are described in U.S. Pat. Nos. 7,303,106; 6,053,390; 5,588,579; 5,119,983; 5,005,749; 4,646,745; 4,576,167; and 4,473,077, each of which is incorporated herein in its entirety by reference. Typically, these instruments include an elongated shaft having a handle portion at a proximal end to actuate the instrument and a staple holding component disposed at a distal end. An anvil assembly including an anvil rod with attached anvil head is mounted to the distal end of the instrument adjacent the staple holding component. Opposed end portions of tissue of the hollow organ(s) to be stapled are clamped between the anvil head and the staple holding component as these components are approximated. The clamped tissue is stapled by driving one or more staples from the staple holding component through the staple slots so that the ends of the staples pass through the tissue and are deformed by anvil pockets of the anvil head. An annular knife is concurrently advanced to core tissue with the hollow organ to free a tubular passage within the organ. 
     Besides anastomosis of hollow organs, surgical stapling devices for performing circular anastomosis have been used to treat internal hemorrhoids in the rectum. Hemorrhoids are masses of tissue in the anus containing enlarged blood vessels. Internal hemorrhoids are inside the anal canal; external hemorrhoids lie outside the anal canal. In hemorrhoidectomy, the hemorrhoids are removed. Stapled hemorrhoidopexy is a surgical procedure in which the stapling device is used to remove tissue just above the hemorrhoids in order to pull the hemorrhoids back up inside the rectum and reduce the symptoms. The staples interrupt the blood flow of the superior hemorrhoidal arterial branches, cutting off the blood supply to the tissue, thus causing the hemorrhoids to shrink. 
     During the use of a circular stapling device for hemorrhoid treatment, the anvil head and the staple holding component of the device are inserted through and into the rectum with the anvil head and the stapling holding component in an open or unapproximated position. 
     Thereafter, a purse string suture is used to pull the internal hemorrhoidal tissue and/or mucosal tissue toward the anvil rod. Next, the anvil head and the staple holding component are approximated to clamp the hemorrhoidal tissue and/or mucosal tissue between the anvil head and the staple holding component. The stapling device is fired to remove the hemorrhoidal tissue and/or mucosal tissue and staple the cut tissue. 
     It would be advantageous to provide additional structure for aligning the staple slots and the anvil pockets when the staple holding component and anvil assembly are approximated. 
     SUMMARY 
     The present invention provides in one aspect a surgical stapler comprising a handle assembly, an elongated body portion extending distally from the handle assembly, and a head portion disposed adjacent a distal portion of the elongated body portion and including an anvil assembly and a shell assembly. The anvil assembly is movable in relation to the shell assembly between spaced and approximated positions. The shell assembly includes a pusher movable distally to advance staples from the shell assembly into contact with the anvil assembly. First and second alignment pins operatively associated with the pusher have distal ends positioned distally of the pusher. The alignment pins are movable between a first non-engaged position spaced from the anvil assembly and a second position in engagement with the anvil assembly. 
     Preferably, the anvil assembly includes an anvil head having a first opening to receive the first alignment pin and a second opening to receive the second alignment pin. Preferably, the first and second alignment pins are frictionally received in the first and second openings, respectively. The anvil assembly can include an anvil shaft extending proximally of the anvil head and being removably mounted to an anvil retainer of the stapler. 
     In a preferred embodiment, advancement of the staple pusher advances the alignment pins to the second position as the first and second alignment pins are advanced through openings in the staple guide. The surgical stapler can include a plurality of staples arranged in an annular row with the alignment pins positioned radially inwardly of the annular row of staples. The alignment pins can also be positioned radially outwardly of a knife of the stapler. 
     In some embodiments, the anvil head has a number of openings exceeding the number of alignment pins for selective engagement of the alignment pins with the respective number of openings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the presently disclosed device are described herein with reference to the drawings, wherein: 
         FIG. 1  is a side view of the stapler of the present disclosure incorporating the alignment pins of the present disclosure; 
         FIG. 1A  is a close up perspective view of the shell assembly of the stapler of  FIG. 1  with the anvil assembly in the approximated position; 
         FIG. 2  is an exploded view showing the anvil head, alignment pins and an end portion of the shell assembly of  FIG. 1 ; 
         FIG. 2A  is a side view of the anvil assembly of  FIG. 1 ; 
         FIG. 2B  is an exploded view of the shell assembly of  FIG. 1 ; 
         FIG. 3  is an enlarged perspective view of the end portion of the shell assembly with alignment pins; 
         FIG. 4  is a cross-sectional view taken along lines  4 - 4  of  FIG. 1A  showing the stapler in the approximated unfired position; and 
         FIG. 5  is a cross-sectional view similar to  FIG. 4  showing the end portion of the stapler in the fired position. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The presently disclosed surgical stapler 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. Throughout this description, the term “proximal” will refer to the portion of the stapler closer to the operator and the term “distal” will refer to the portion of the instrument further from the operator. The presently disclosed stapler is particularly suited for surgical procedures for the treatment of colon prolapse and hemorrhoids. 
       FIG. 1  illustrates the presently disclosed hemorrhoid stapler  10 . Briefly, surgical stapler  10  includes a handle assembly  12 , a central body portion  14 , and a distal head portion  16 . Head portion  16  includes an anvil assembly  18  and a shell assembly  20 . 
     Handle assembly  12  includes a stationary handle  22 , a firing trigger  24 , an approximation knob  26 , an indicator assembly  28 , and a lockout mechanism  30 . Approximation knob  26  functions to retract and advance a drive screw  32  to advance or retract anvil assembly  18  in relation to shell assembly  20 . Firing trigger  24  functions to advance a pusher link  34  to eject staples from shell assembly  20 . Each of the components of handle assembly  12  identified above are as described in U.S. Pat. No. 7,303,106 (“106 patent”), the entire contents of which are incorporated herein by reference. Accordingly, these components and assemblies will not be described in detail herein. 
     Referring to  FIG. 2A , anvil assembly  18  includes an anvil shaft  64  and an anvil head  66 . (The anvil shaft has been removed from  FIGS. 2 ,  4  and  5  for clarity.) Anvil shaft or center rod  64  includes a tapered blunt end  64   a . End portion  64   b  is dimensioned to receive a central hub portion  70  of anvil head  66 . End  64   b  of shaft  64  and hub portion  70  of anvil head  66  each define a throughbore dimensioned to receive a pin, screw, rivet, or the like  72  for fixedly securing anvil head  66  to anvil shaft  64 . The anvil head can be fixedly (non-rotatably) mounted to the anvil shaft or alternatively the anvil head can be mounted for tilted movement with respect to the anvil shaft as described for example in U.S. Pat. Nos. 6,053,390; 6,957,758; 7,168,604; 7,431,191; and U.S. Publication No. 2008-0230581. The entire contents of each of these patents/applications are incorporated herein by reference. 
     Anvil shaft  64  includes a stepped surface or ring  74  between end  64   a  and end  64   b  which is configured to engage retention surfaces of flexible arms of anvil retainer  36  to releasably secure anvil shaft  64  to anvil retainer  36 . Anvil retainer  36  has a bore to receive the anvil shaft  64 . Anvil shaft  64  also includes over-molded splines  76 . Alternatively, the splines can be machined onto the anvil shaft. The splines  76  align the anvil shaft  64  with respect to the anvil retainer  36  of the instrument to thereby align anvil assembly  18  with shell assembly  20  to ensure the staples are properly aligned with the anvil pockets. A series of longitudinally spaced suture holes  78   a ,  78   b ,  78   c  are formed at a distal region of the anvil shaft  64 . Each of the suture holes  78  provides for a purse-string attachment location. As shown, three holes are provided, although a fewer or greater number of holes are also contemplated. The holes are configured to receive a purse-string suture therethrough. The series of holes  78  enables the user to decide the amount of tissue desired for purse stringing, e.g. hole  78   a  would enable additional tissue to be taken and presented for stapling. That is, holes  78  are longitudinally spaced along anvil shaft  64  such that the amount of tissue drawn into the shell assembly  20  can be controlled by properly selecting the hole  78  to which the purse string suture is inserted. Vent holes  69  of anvil head  66  are illustrated in  FIG. 1A . The anvil head  66  also includes openings  67  for receipt of alignment pins discussed in detail below. 
     An orientation groove or grooves  84  ( FIG. 2A ) is provided in anvil shaft  64  beneath splines  76 . Orientation groove(s)  84  functions to effect proper alignment of splines  76  about shaft  64  to facilitate proper alignment of anvil assembly  18  and shell assembly  20  when anvil assembly  18  is retracted towards shell assembly  20 . 
     Anvil head  66  defines an outer annular recess which supports an anvil plate  90  and an inner annular recess which supports a cut ring  94 . Anvil plate  90  has a plurality of anvil pockets  91  arranged in an annular array for deforming the staples are. Cutting ring  94  is an annular member that is positioned within an inner annular recess  95  formed in anvil head  66 . The cutting ring  94  includes respective proximal and distal ends  98 A,  98 B ( FIG. 5 ), and defines an inner proximally facing annular shoulder  98 C, as well as an outer proximally facing annular surface  98 D. The inner annular shoulder  98 C and the annular surface  98 D of the cutting ring  94  are configured and dimensioned for engagement with the anvil head  66  such that the cutting ring is retained within the recess  95 . Anvil head  66  includes an inner wall with an outwardly extending finger  71 A that is configured and dimensioned for engagement with the inner annular shoulder  98 C, and an outer wall with an inwardly extending finger (not shown) that is configured and dimensioned for engagement with the outer annular surface  98 D. During use of the stapling device  10 , upon firing, the cutting ring  94  is penetrated by the annular knife  102 . Anvil head  66  has a bulbous, smoothly contoured member  96  defining its distal face. Bulbous member  96  facilitates insertion of anvil head  66  through a purse-string suture. 
     Referring to  FIGS. 1 ,  2 B and  4 , shell assembly  20  is secured to the distal end of central body portion  14  in a manner substantially similar to that described in the &#39;106 patent incorporated herein by reference. Shell assembly  20  includes a shell or housing  198 , a pusher back  100  positioned within housing  198 , a cylindrical knife  102 , and a staple guide  104 . Staple guide  104  houses one or more annular rows of staples  150 . 
     Shell  198  includes an outer housing portion  196  and an inner guide portion  108  having grooves for mating with splines  76  on the anvil shaft  64 . Outer housing portion  196  defines a throughbore  192  having a distal cylindrical section  114 , a central conical section  116 , and a proximal smaller diameter cylindrical section  118 . A plurality of openings  120  are formed in conical section  116 , dimensioned to permit fluid and tissue passage during operation of stapler  10 . A pair of diametrically opposed flexible engagement members  117  are formed on proximal cylindrical section  118  of shell  198  for reception in openings formed on a distal end body portion  14  to secure shell  198  to body portion  14 . 
     Pusher back  100  includes a central throughbore  120  which is slidably positioned about inner guide portion  108  of shell  98 . Pusher back  100  includes a distal cylindrical section  127  which is slidably positioned within distal cylindrical section  114  of shell  198 , a central conical section  125 , and a proximal smaller diameter cylindrical section  129 . The proximal end of pusher back  100  includes members  132  which are configured to lockingly engage with pusher link  34  of stapler  10  as described in the &#39;106 patent incorporated by reference herein. Pusher back  100  also defines a receptacle for receiving excised tissue. 
     Referring to  FIG. 1 , a rigid bushing  140  is supported in the proximal end of inner guide portion  108  of shell  198 . Bushing  140  defines a throughbore dimensioned to slidably receive anvil retainer  36  and anvil shaft  64  of anvil assembly  18 . 
     The distal end of pusher back  100  includes a pusher  126  ( FIG. 2B ). Pusher  126  includes a multiplicity of distally extending fingers  128  dimensioned to be slidably received within slots  105  formed in staple guide  104  to eject staples  150  therefrom. Cylindrical knife  102  is retained within the central throughbore  120  of pusher back  100  to fixedly secure knife  102  in relation to pusher  126 . Knife  102  may be retained within pusher back  100  using adhesives, crimping, pins, friction, etc. The distal end of knife  102  includes a circular cutting edge. 
     The rigid bushing  140  is supported in the proximal end of inner guide portion  108  of shell  198 . Bushing  140  defines a throughbore dimensioned to slidably receive anvil retainer  36  and anvil shaft  64  of anvil assembly  18 . Anvil retainer  36  is connected to drive screw  32  by connector  38  as a proximal end of connector  38  is connected to a distal end of drive screw  32  via pin  60 . Bushing  140  provides lateral support for flexible arms  48  of anvil retainer  36  when the anvil assembly  18  has been approximated to prevent disengagement of anvil assembly  18  from anvil retainer  36 . In the unapproximated position, flexible arms  48  of anvil shaft  64  are positioned externally of bushing  140  to permit removal of anvil assembly  18  from anvil retainer  36 . 
     As discussed above, stapler  10  is particularly suitable for use in surgical procedures for treating hemorrhoids. During such a procedure, an access port can be inserted into the anus to facilitate access to the hemorrhoids. Next, a purse string suture (not shown) is placed into, above or in the vicinity of the hemorrhoids and the anvil assembly  18  is inserted through the access port into the anus and rectum. Bulbous member  96  of anvil head  66  functions to allow smooth passage of anvil assembly  18  past the purse string suture. Anvil assembly  18  and shell assembly  20  are approximated via knob  26  to draw the hemorrhoids into shell assembly  20 . 
     When surgical stapler  10  is fully approximated ( FIGS. 1A and 4 ), firing trigger  24  can be actuated or fired in a manner described in the &#39;106 patent  10  to staple, sever and allow removal of a portion of the hemorrhoids. Thereafter, stapler  10  is removed from the body with the excised tissue contained within the receptacle of pusher back  100  within shell assembly  20 . 
     Shell assembly  20  has a plurality of projections shown in the form of alignment pins  171  engagable with alignment openings  67  in the anvil assembly (see e.g.  FIGS. 2 and 4 ). More specifically, the pins  171  extend distally from pusher back  100  and extend through openings  109  in the staple guide  104 , functioning as described below to help align the anvil head  66  and shell assembly  20  and to limit axial movement of the anvil head  66 , especially in the instance where a relatively long anvil shaft is provided such as in certain hemorrhoid staplers. The alignment pins  171  can be attached to the pusher back  100  via interference ribs press fit into holes into pusher back  100  or by other methods such as screw threads. It should be appreciated that the alignment pins (projections) can also be utilized on other circular staplers in addition to stapler  10 . The pins  171  can have tapered ends  173  as shown. Alternately, they can have planar ends or other configurations. 
     The pins function to limit movement of the anvil head  166  with respect to the shell assembly  120 . In one embodiment, the pins  171  have an outer dimension substantially equal to the inner diameter of the alignment openings  67  of the anvil assembly to frictionally fit within the alignment openings  67  with sufficient force for retention, while not inhibiting re-approximation of the anvil assembly. In other embodiments, the pins can have a smaller outer dimension in relation to the inner diameter of the alignment openings to thereby more loosely be seated in the alignment openings, while still functioning to limit axial movement and rotational movement of the anvil head. The pins  171  are preferably outboard (radially outward) of the circular knife  102  of the stapler  10  and inboard (radially inward) of the staples  150 . Pins  171  are shown spaced approximately 180 degrees apart. Two or more pins substantially equally radially spaced or spaced at varying intervals can be provided. Although the pins  171  are shown for use with an anvil shaft having through holes  175  for a purse string suture, the pins can be used with staplers having other anvil shafts. Also, the alignment pins  171  can be used with non-pivoting anvils as well as pivotally mounted anvils which move from non-tilted to tilted operative positions, such as those disclosed in the U.S. patents/publication listed above. 
     The anvil head  66  is shown with a plurality of openings  67  to receive alignment pins  171 . The openings are positioned radially inward of the annular array of staple forming (anvil) pockets. At minimum, the number of anvil openings  67  is equal to the number of alignment pins  171 . However, it is also contemplated, as shown in the illustrated embodiment, that there are more anvil openings  67  than alignment pins. For example, in the illustrated embodiment, two alignment pins  171  are provided while eight anvil openings  67  are provided. In this manner, the alignment pins  171  can align with two of the respective anvil openings  67  at various orientations of the anvil head  66  with respect to the shell assembly  20 . 
     In use, upon firing of the stapler  10 , the pusher back  100  is advanced distally to advance the staple pusher  126  with fingers  128  into contact with the staples  150  positioned within slots  105  in the staple guide  104 . As the pusher  126  is advanced distally, alignment pins  171 , operatively associated with the pusher  126  via their attachment thereto, are likewise moved distally. The alignment pins  171  move distally from a retracted, non-engaged position shown in  FIG. 4  where they are retracted within the shell assembly to an advanced position protruding beyond the shall assembly and into engagement with the anvil openings  67  of the anvil head  66 . 
     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 preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.