Abstract:
An anvil assembly comprising an anvil shaft and an anvil head, the anvil head having anvil depressions for forming surgical staples, and the anvil head mounted to the anvil shaft. The anvil shaft has a longitudinal axis and a helical slot formed therein. A disk is movable along the slot to a selected position to selectively adjust the positioning of a purse string suture.

Description:
[0001]    This application claims priority from provisional application Ser. No. 61/144,488, filed Jan. 14, 2009, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a surgical stapling device and more particularly to a surgical stapling device suitable for treatment of internal hemorrhoids. 
         [0004]    2. Background of Related Art 
         [0005]    Anastomosis is the surgical joining of separate hollow organ sections. In known circular anastomosis procedures, two ends of organ sections are joined by means of a stapling device which drives a circular array of staples through each organ section and simultaneously cores any tissue interior of the driven circular array of staples to free a tubular passage. Examples of such devices are described n U.S. Pat. Nos. 7,234,624, 6,945,444, 6,053,390, 5,588,579, 5,119,983, 4,646,745, 4,576,167, 4,473,077. 
         [0006]    Typically the circular stapling device has an elongated shaft having a handle portion at a proximal end and a staple cartridge at a distal end. An anvil assembly including an anvil rod with an attached anvil head is mounted to the distal end of the device. The anvil is approximated to clamp tissue between the staple holding component and the anvil. The clamped tissue is stapled by actuation of the handle portion to drive circular arrays of staples through the tissue and into anvil depressions on the anvil head to form the staples. An annular knife is advanced with the handle actuation to core tissue inboard of the staple array. 
         [0007]    Surgical stapling devices for performing circular anastomosis have also been used to treat 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. Hemorrhoidectomy is a surgical procedure in which the hemorrhoids are removed. Stapled hemorrhoidopexy is a surgical procedure in which a 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, thus causing the hemorrhoids to shrink. This is used for treatment of internal hemorrhoids. 
         [0008]    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. 
         [0009]    It would be advantageous to provide a device with an option to adjust the amount of tissue for purse stringing to enhance control over the amount of tissue removed. 
       SUMMARY 
       [0010]    The present disclosure provides an anvil assembly comprising an anvil shaft and an anvil head, the anvil head having anvil depressions for forming surgical staples. The anvil head is mounted to the anvil shaft. The anvil shaft has a longitudinal axis and a helical slot formed therein. A rotatable disc composed of two separate components is movable along the slot to a selected position to selectively adjust the amount of tissue for purse stringing. The disc can also be used to adjust the tension on a purse string suture placed about the anvil shaft. The disc has an internal thread to threadingly engage the helical slot of the anvil shaft. 
         [0011]    In one embodiment, the two components of the disc are attached by a pin and slot arrangement. 
         [0012]    The anvil assembly preferably has a mounting structure on the anvil shaft for releasably mounting the anvil shaft to a stapling instrument. 
         [0013]    The present disclosure also provides 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 end 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 anvil assembly has an anvil head and an anvil shaft with a helical slot formed therein. A rotatable disc composed of two components attachable to each other is movable along the helical slot to a selected position to adjust the amount of tissue drawn into the shell assembly by a purse string suture. 
         [0014]    In a preferred embodiment, the anvil shaft is removably mounted to an anvil retainer of the stapler. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein: 
           [0016]      FIG. 1  is a perspective view of a first embodiment of the surgical stapler of the present disclosure; 
           [0017]      FIG. 1A  is a longitudinal cross-sectional view of the surgical stapler of  FIG. 1 ; 
           [0018]      FIG. 1B  is a cross-sectional view of the anvil retainer of the stapler of  FIG. 1 ; 
           [0019]      FIG. 1C  is a side view of the connector of the stapler of  FIG. 1 ; 
           [0020]      FIGS. 1D and 1E  are cross-sectional views of portions of the shell assembly of  FIG. 1 ; 
           [0021]      FIG. 2  is a close up perspective view of the anvil assembly and shell assembly of  FIG. 1 ; 
           [0022]      FIG. 3  is a perspective view of the disc of  FIG. 1 ; 
           [0023]      FIG. 4  is a perspective view of an alternate embodiment of the disc composed of two attachable components; 
           [0024]      FIG. 5  is a close up side view of the anvil assembly and shell assembly of  FIG. 1  with the disc shown in cross-section; and 
           [0025]      FIG. 6  is a side view illustrating placement of the purse string suture in an anvil assembly of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0026]    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, although it can be used for other procedures. 
         [0027]      FIGS. 1 and 1A  illustrate one embodiment of the presently disclosed hemorrhoid stapler  10 . Briefly, surgical stapler  10  includes a handle assembly  12 , a central body or elongated portion  14  and a distal head portion  16 . Head portion  16  includes an anvil assembly  18  and a shell assembly  20 . Except where otherwise noted, the components of stapler  10  are generally formed from thermoplastics including polycarbonates, and metals including stainless steel and aluminum. The particular material selected to form a particular component will depend upon the strength requirements of the particular component. For example, the anvil may be formed from a metal such as stainless steel, whereas portions of handle assembly  12  may be formed from thermoplastic such as a polycarbonate. Alternately, other materials having the requisite strength requirements which are suitable for surgical use may be used to form the components of stapler  10 . 
         [0028]    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 cartridge assembly  20 . Firing trigger  24  functions to advance a pusher link  34  to actuate a pusher to eject staples from shell assembly  20 . Each of the components of handle assembly  12  identified above are substantially as described in U.S. Pat. No. 7,303,106 (“&#39;106 patent”) entitled “Surgical Stapling Device With Visual Indicator” which issued on Dec. 4, 2007. The &#39;106 patent is incorporated herein by reference in its entirety. Accordingly, these components and assemblies will not be described in detail herein. 
         [0029]    Referring to  FIGS. 1A-1C , an anvil retainer  36  is secured to a distal end of drive screw  32  by a connector  38 . Anvil retainer  36  includes a body  40  defining an elongated bore  42 . A proximal end  40   a  of body  40  includes a longitudinal slot  44  and a pair of transverse throughbores  46 . A distal end  40   b  of body  40  includes three segmented flexible arms  48 . Each of the arms  48  has an inner retention surface  50  which will be described in further detail below. 
         [0030]    Connector  38  includes a central body  52  having a proximal extension  54  and a distal extension  56 . Proximal extension  54  is dimensioned to be received within a slot (not shown) formed in the distal end of drive screw  32 . Extension  54  and the distal end of drive screw  32  each define a transverse throughbore for receiving a pin, rivet, screw or the like  60  for fixedly securing connector  38  to drive screw  32 . Distal extension  56  is dimensioned to be received within slot  44  of body  40  of anvil retainer  36 . Extension  56  includes a pair of spaced throughbores which align with throughbores  46  of anvil retainer  36  and are dimensioned to receive pins, screws, rivets or the like  62  to fixedly secure anvil retainer  36  to connector  38 . Although pins, screws, rivets or the like are specifically disclosed for securing connector  38  to drive screw  32  and anvil retainer  36 , other known fastening techniques are envisioned, e.g., welding, crimping, and interlocking structure. In an alternate embodiment, the connector and anvil retainer can be replaced with a single part, e.g. an elongated anvil retainer, having an extended length to function similarly to the extended length resulting from the provision of connector  38 . 
         [0031]    Referring to  FIGS. 2 and 5 , anvil assembly  18  includes an anvil shaft or center rod  64  and an anvil head  66 . Anvil shaft  64  includes a tapered proximal blunt end  64   a  ( FIG. 1A ) and an opposite distal end for mounting to anvil post  68  of anvil head  66 . A pin  72  (or alternatively a screw, rivet or the like) mounts the anvil post  68  to anvil shaft  64 . It should be appreciated, that anvil post  68  can be pivotally mounted to anvil shaft  64  so that the anvil can move between an operative non-tilted position to a tilted position. This is described in detail in U.S. Pat. No. 7,303,106, the entire contents of which is incorporated herein by reference. Alternatively the anvil can be fixedly (non-pivotably) mounted to the anvil shaft  64 . 
         [0032]    Anvil shaft  64  includes a stepped surface or ring  74  which is configured to engage retention surfaces  50  ( FIG. 1B ) of flexible arms  48  to releasably secure anvil shaft  64  to anvil retainer  36 . An orientation groove or grooves is provided in anvil shaft  64  beneath splines  76  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 . 
         [0033]    Anvil shaft  64  also includes over-molded splines  76 . Splines  76  function as known in the art to properly align anvil assembly  18  with shell assembly  20  ( FIG. 1 ). Alternatively, the anvil shaft can have machined splines. 
         [0034]    Anvil shaft  64  has a helical cam slot or groove  78  formed therein. An adjustable movable member  79  having an internal thread  81  engages the helical slot  78  on the anvil shaft  64 . The movable member  79  is rotated to slide in an adjustable nut fashion either distally or proximally along slot  78  and therefore along anvil shaft  64  to adjust the positioning of the purse string and/or the tension on the purse string as described below. 
         [0035]    In the embodiment of  FIGS. 2 and 3 , the movable (rotatable) member is in the form of a unitary disc  79 . In the alternate embodiment of  FIG. 4 , disc  179  is composed of two components  179   a ,  179   b . The components  179   a ,  179   b  are shown attached by a pin  182 /slot  184  arrangement, although other structures for attaching the two components are also contemplated. This two component version  179  eases assembly as each disc half is placed over the anvil shaft  64  and then fitted together. It also enables the disc to be removed by the user if not desired or be provided as an optional accessory to be placed on the anvil shaft if the surgeon desires such selective adjustment of the purse string suture. 
         [0036]    The disc is configured to provide a locator for a purse-string suture, creating a region or stop to retain the suture. The disc  79 ,  179  enables the user to decide the amount of tissue desired for purse stringing, e.g. moving the disc to a more proximal position (i.e. further from the anvil head) would enable additional tissue to be taken and presented for stapling. Thus, the disc can be moved to a selected position prior to securing the purse string around the anvil shaft  64 . 
         [0037]    The disc  79 ,  179  can also be used as a tissue tensioner. In this manner, after the purse string suture is placed about the anvil shaft  64 , the disc can be rotated along the helical slot (proximally) to apply additional tension to the suture to present additional tissue in the shell assembly for subsequent stapling. 
         [0038]    The disc  79  has a distal surface  82  closer to the anvil head and a proximal surface  84  closer to the shell assembly. Both the proximal and distal surfaces  82 ,  84  are preferably angled, with the distal surface angled such that the surface angles in a proximal direction and the proximal surface angled so the surface angles in a distal direction. This is best shown in  FIG. 5 . 
         [0039]    As discussed above, anvil retainer  36  ( FIG. 1B ) defines an elongated bore  42  which is dimensioned to receive anvil shaft  64  such that stepped surface  74  of shaft  64  engages retention surface  50  to releasably secure anvil assembly  18  to anvil retainer  36 . In one embodiment, anvil shaft  64  is of a length to protrude from the anus when properly positioned during a surgical procedure to treat colon prolapse. By protruding from the anus, the interface between the anvil shaft  64  and anvil retainer  36  is exposed and visible for attachment. For example, in one embodiment, shaft  64  extends outwardly from a face  86  ( FIG. 2 ) of anvil head  66  a distance greater than about three inches, and for example extends outwardly from face  86  of anvil head  66  a distance of about 3.55 inches. In another embodiment, the shaft extends outwardly a distance of greater than about five inches, and for example extends about 5.234 inches. 
         [0040]    Anvil head  66  is shown with a low distal profile, however, other shapes are contemplated such as the bulbous, smoothly contoured anvil  266  illustrated in  FIG. 3A . Bulbous portion  296  facilitates insertion of head  266  through a purse string suture. The anvil head  266  can be attached to the anvil shafts disclosed herein. 
         [0041]    Referring to  FIGS. 1A ,  1 D and  1 E, 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  98 , a pusher back  100 , a cylindrical knife  102 , and a staple guide  104 . Staple guide  104  houses one or more rows of staples (not shown). 
         [0042]    Shell  98  includes an outer housing portion  106  and an inner guide portion  108  having grooves  110  for mating with splines  76  on anvil shaft  64 . Outer housing portion  106  defines a throughbore  112  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 . Openings  116  are dimensioned to permit fluid and tissue passage during operation of stapler  10 . A pair of diametrically opposed flexible engagement members  122  are formed on proximal cylindrical section  118  of shell  98 . Engagement members  122  are positioned to be received in openings formed on a distal end of body portion  14  to secure shell  98  to body portion  14 . Vent holes  29  ( FIG. 1 ) are provided in shell assembly  20 . 
         [0043]    Pusher back  100  includes a central throughbore  124  which is slidably positioned about inner guide portion  108  of shell  98 . Pusher back  100  includes a distal cylindrical section  126  which is slidably positioned within distal cylindrical section  114  of shell  98 , a central conical section  128  and a proximal smaller diameter cylindrical section  130 . The proximal end of pusher back  100  includes members  132  which are configured to lockingly engage with a pusher link of stapler  10  as described in the &#39;106 patent incorporated by reference herein. Pusher back  100  also defines a receptacle  133  for receiving excised tissue. Receptacle  133  is configured to have a depth of between about 0.75 inches and about 2.00 inches. In one embodiment, receptacle  133  has a depth of about 1.33 inches. 
         [0044]    The distal end of pusher back  100  includes a pusher  134  ( FIG. 1E ). Pusher  134  includes a multiplicity of distally extending fingers  136  dimensioned to be slidably received within slots (not shown) formed in staple guide  104  to eject staples (not shown) therefrom. Cylindrical knife  102  is retained within the central throughbore of pusher back  100  to fixedly secure knife  102  in relation to pusher  134 . 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. 
         [0045]    The rigid bushing  140  is supported in the proximal end of inner guide portion  108  of shell  98 . Bushing  140  defines a throughbore dimensioned to slidably receive anvil retainer  36  and anvil shaft  64  of anvil assembly  18 . 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  are positioned externally of bushing  140  to permit flexing of the arms for removal of anvil assembly  18  from retainer  36 . 
         [0046]    As discussed above, stapler  10  is particularly suitable for use in surgical procedures for treating colon prolapse. During such procedure, an access port can be inserted into the anus to facilitate access to the prolapsed colon. Next, a purse string suture is placed into, above or in the vicinity of the colon prolapse. Disc member  79  (or  179 ) is rotated for movement along the anvil shaft  64  to a selected position, depending on the amount of tissue desired to be drawn in the shell assembly and presented for stapling, and the anvil assembly  18  is inserted through the access portion into the anus and rectum. Thereafter, the purse string suture ( FIG. 6 ) is placed about the anvil shaft  64  abutting the disc  79 ,  179  which retains the suture position. A greater amount of tissue will be drawn into shell assembly  20  by retaining the purse string suture against a more proximal position of the disc. The suture ends are tightened and pulled toward the user, therefore pulling the tissue proximally. The surgeon can then visualize the tissue to be stapled, i.e. the tissue donut to be removed. The stapling instrument, e.g. instrument  10  of  FIG. 1 , is inserted through the port and attached to the anvil assembly, with the elongated anvil shaft and elongated instrument shaft providing increased visibility. At any point, if desired, the disc  79 ,  179  can be rotated to a more proximal position to apply additional tension on the suture. Anvil assembly  18  and shell assembly  20  are then approximated via knob  26  to draw the prolapsed colon into shell assembly  20 . 
         [0047]    When surgical stapler  10  is fully approximated, firing trigger  24  can be actuated or fired in a manner described in the &#39;106 patent to staple, sever and allow removal of a portion of the prolapsed colon. Thereafter, the stapler is at least partially unapproximated and removed from the anus with the excised tissue contained within receptacle  133  of pusher back  100  within shell assembly  20 . In the embodiments where a tilting anvil is used, after the firing step and sufficient movement of the anvil away from the shell assembly  20 , the anvil will tilt (not shown) to its inoperative position to facilitate removal. 
         [0048]    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.