Abstract:
Introducers for introducing a surgical circular stapler into a patient. Various embodiments comprise cover members that are applied over a stapling head portion of the circular stapler. In some embodiments, the cover members are fabricated from a flexible stretchable material and have a bumper portion that protrudes distally beyond the distal face of the stapling head. The staples may be fired through the cover member and the balance of the cover member is withdrawn from the patient with the stapling head. Other cover embodiments are selectively movable from a position wherein the distal face of the stapling head is covered and other positions wherein the distal face of the stapling head is exposed.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to surgical staplers, and more particularly, to devices and methods for introducing a circular stapling device into the colon of a patient. 
       BACKGROUND 
       [0002]    In certain types of surgical procedures, the use of surgical staples has become the preferred method of joining tissue and, as such, specially configured surgical staplers have been developed for these applications. For example, intra-luminal or circular staplers have been developed for use in surgical procedures involving the lower colon wherein sections of the lower colon are joined together after a diseased portion has been excised. Circular staplers useful for performing such procedures are disclosed, for example, in U.S. Pat. Nos. 5,104,025; 5,205,459; 5,285,945; and 5,309,927 which are each herein incorporated by reference in their respective entireties. 
         [0003]    In general, a conventional circular stapler typically consists of an elongated shaft that has a proximal actuating mechanism and a distal stapling mechanism mounted to the elongated shaft. The distal stapling mechanism commonly consists of a fixed stapling cartridge that contains a plurality of staples configured in a concentric circular array. A round cutting knife is concentrically mounted in the cartridge interior to the staples for axial travel therein. Extending axially from the center of the cartridge is a movable trocar shaft that is adapted to have a staple anvil removably coupled thereto. The anvil is configured to form the ends of the staples as they are driven into it. The distance between a distal face of the staple cartridge and the staple anvil is commonly controlled by an adjustment mechanism that is mounted to the proximal end of the stapler shaft for controlling the axial movement of the trocar. Tissue that is clamped between the staple cartridge and the staple anvil is simultaneously stapled and cut when the actuating mechanism is activated by the surgeon. 
         [0004]    When performing a lower colon procedure using a circular stapler, the intestine is typically stapled using a conventional surgical stapler with double rows of staples being emplaced on either side of the diseased portion of intestine to be removed. The target section is simultaneously cut as the adjoining end is stapled. After removing the diseased portion, the surgeon typically inserts the anvil into the proximal end of the lumen, proximal of the staple line. This is done by inserting the anvil head into an entry port cut into the proximal lumen by the surgeon. On occasion, the anvil can be placed transanally, by placing the anvil head on the distal end of the stapler and inserting the instrument through the rectum. The surgeon then ties the proximal end of the intestine to the anvil shaft using a suture or other conventional tying device. Next, the surgeon cuts excess tissue adjacent to the tie and the surgeon attaches the anvil to the trocar shaft of the stapler. The surgeon then closes the gap between the anvil and cartridge, thereby clamping the proximal and distal ends of the intestine in the gap. The surgeon next actuates the stapler causing several rows of staples to be driven through both ends of the intestine and formed, thereby joining the ends and forming a tubular pathway. Simultaneously, as the staples are driven and formed, the concentric circular knife blade is driven through the intestinal tissue ends, cutting the ends adjacent to the inner row of staples. The surgeon then withdraws the stapler from the intestine and the procedure is complete. 
         [0005]    During such lower colon procedures, it may be difficult to insert the surgical stapler thru the anus and past the transverse folds in the rectal wall that protrude into the colon which are commonly referred to as the “Valves of Houston” and subsequently manipulated to the desired area. This problem is exacerbated when the stapler must be inserted without the anvil in position. In particular, the forward or distal end of most circular staplers comprises a relatively abrupt circular-shaped member designed to support a circular staple cartridge. Such blunt/abrupt shape makes it difficult to advance the forward end of the stapler past the Valves of Houston and other tissue. 
         [0006]    Thus, the need exists for devices and methods for easily inserting a surgical stapler through a patient&#39;s anus into the lower colon or into other areas within the patient. 
         [0007]    The foregoing discussion is intended only to illustrate some of the shortcomings present in the field of the invention at the time, and should not be taken as a disavowal of claim scope. 
       BRIEF SUMMARY 
       [0008]    In connection with various embodiments of the present invention there is provided an introducer for introducing a surgical circular stapler that has a stapling head that supports an annular staple cartridge therein into a patient. In various embodiments, the introducer comprises a hollow sheath that has an open proximal end that is sized to be inserted over at least a distal portion of the stapling head. The hollow sheath further has a distal end that defines a circumferentially-extending bumper portion that covers a distal face of the annular staple cartridge and extends above a plane formed by the distal face. 
         [0009]    In another general aspect of the present invention, there is provided an introducer for introducing a surgical circular stapler that has a stapling head into a patient. In various embodiments, the introducer comprises a cover member that has a body portion sized to be installed on a portion of the stapling head of the circular stapler. The body portion may have a plurality of flexible fingers that protrude distally therefrom such that a distal tip of the fingers converge toward each other to cover a distal face of the stapling head when the body portion is installed thereon. 
         [0010]    In another general aspect of the present invention, there is provided an introducer for introducing a surgical circular stapler that has a stapling head and an axially movable trocar into a patient. In various embodiments, the introducer comprises a cover member that has a centrally-disposed hub that is configured to be engaged by a distal end portion of the trocar when the cover member is installed on the stapling head and the distal end portion of the trocar is advanced distally beyond a distal face of the stapling head. The centrally-disposed hub may have at least three fingers that protrude therefrom. Each of the fingers may have a proximal end portion that is configured to retainingly engage the stapling head. 
         [0011]    In connection with yet another general aspect of the present invention, there is provided an introducer for introducing a surgical circular stapler that has a stapling head into a patient. In connection with various embodiments of the present invention, the introducer comprises a strip member that forms a ring-like base portion that is sized to retainingly engage a distal end portion of the stapling head. The strip member may be wound from the base portion in a spirally wound, closed-ended configuration to substantially cover a distal face of the stapling head. The introducer may further comprise a retainer member that retains the strip member in the spirally wound closed-ended configuration and the base portion in retaining engagement with the distal end portion of the stapling head. A release member may be coupled to a portion of the strip member such that, upon application of a release motion to the release member, the strip member unwinds from engagement with the distal portion of the stapling head. 
         [0012]    In connection with other general aspects of the present invention, there is provided an introducer for introducing a surgical circular stapler that has a stapling head into a patient. In connection with various embodiments, the introducer comprises a base portion that is sized to retainingly engage a distal end portion of the stapling head. At least three flexible segment portions may extend distally from the base portion such that a distal tip of each of the flexible segment portions converge toward the other distal tips to a closed position to cover a distal face of the stapling head when the base portion is installed thereon. A retainer may be provided to releaseably retain the at least three flexible segment portions in the closed position. The introducer may further include a release member that cooperates with the retainer such that, upon application of a release motion to the release member, the retainer permits the at least three segment members to flex open as the introducer is advanced proximally over the stapling head to thereby expose the distal face of the stapling head. 
         [0013]    In connection with yet another general aspect of the present invention, there is provided a method of introducing a surgical circular stapler that has a handle assembly, an elongated shaft that protrudes from the handle assembly, a stapling head that is coupled to the elongated shaft, and a removably attachable anvil into a patient. The method may comprise removing the anvil from the stapler and installing a removable cover member onto a portion of the stapling head such that a portion of the removable cover member protrudes distally beyond a distal face of the stapling head. The method may further comprise inserting the stapling head and cover into the patient and removing the cover from the stapling head. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0014]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention. 
           [0015]      FIG. 1  is a perspective view of a surgical circular stapling instrument; 
           [0016]      FIG. 2  is another perspective view of the circular surgical stapling instrument of  FIG. 1  prior to the installation of an introducer embodiment of the present invention thereon; 
           [0017]      FIG. 3  is a side elevational view of an introducer embodiment of the present invention; 
           [0018]      FIG. 4  is a top view of the introducer of  FIG. 2 ; 
           [0019]      FIG. 5  is a top view of the introducer of  FIGS. 3 and 4 ; 
           [0020]      FIG. 6  is another top view of the introducer of  FIGS. 2-5  with the cover panel removed from the handle assembly; 
           [0021]      FIG. 7  is a partial perspective view of an introducer embodiment of the present invention installed on a circular stapling instrument; 
           [0022]      FIG. 8  is a partial side elevation view of the introducer and circular stapler of  FIG. 7 ; 
           [0023]      FIG. 9  is a partial top view of the introducer and circular stapler of  FIGS. 7 and 8 ; 
           [0024]      FIG. 10  is an elevational view of a cap assembly embodiment of the present invention; 
           [0025]      FIG. 11  is another elevational view of the cap assembly of  FIG. 10  with the release latch removed therefrom; 
           [0026]      FIG. 12  is a perspective view of the cap assembly of  FIGS. 8-11  with the release latch removed therefrom and the cap disengaged from the barrel assembly; 
           [0027]      FIG. 13  is a cross-sectional view of a cap assembly embodiment of the present invention with the cap engaged with the barrel assembly; 
           [0028]      FIG. 14  is a partial side elevational view of a portion of a circular stapler and a cap of an introducer embodiment of the present invention; 
           [0029]      FIG. 14A  is another partial side elevational view of the circular stapler and cap with the cap sliding off the perimeter of the stapling head portion of the circular stapler; 
           [0030]      FIG. 15  is a top view of a cap assembly embodiment of the present invention with the cap in an open position; 
           [0031]      FIG. 16  is another top view of the cap assembly embodiment of  FIG. 15  with a line illustrating a low profile cap embodiment; 
           [0032]      FIG. 18  is a top perspective view of a cap assembly embodiment of the present invention; 
           [0033]      FIG. 19  is a bottom view of the cap assembly of  FIG. 18 ; 
           [0034]      FIG. 20  is a top perspective view of another cap assembly embodiment of the present invention; 
           [0035]      FIG. 21  is a bottom view of the cap assembly of  FIG. 20 ; 
           [0036]      FIG. 22  is a perspective view of a circular surgical stapling instrument prior to the installation of another introducer embodiment of the present invention thereon; 
           [0037]      FIG. 23  is a perspective view of a circular surgical stapling instrument prior to the installation of another introducer embodiment of the present invention thereon; 
           [0038]      FIG. 24  is an exploded elevational view illustrating another introducer embodiment of the present invention prior to installation on a portion of a stapling head of a circular stapler; 
           [0039]      FIG. 25  is a cross-sectional view of the introducer of  FIG. 24  installed on a stapling head of a circular stapler; 
           [0040]      FIG. 26  is a distal end view of an introducer embodiment of the present invention; 
           [0041]      FIG. 27  is a distal end view of another introducer embodiment of the present invention; 
           [0042]      FIG. 28  is a distal end view of another introducer embodiment of the present invention; 
           [0043]      FIG. 29  is a cross-sectional view of another introducer embodiment of the present invention installed on a stapling head of a circular stapler; 
           [0044]      FIG. 30  is a side elevational view of another introducer embodiment of the present invention in a closed position; 
           [0045]      FIG. 31  is another side elevational view of the introducer of  FIG. 31 ; 
           [0046]      FIG. 32  is another side elevational view of the introducer of  FIGS. 30 and 31  in a closed position; 
           [0047]      FIG. 33  is a distal end view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler; 
           [0048]      FIG. 34  is a side elevational view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler with the trocar portion of the circular stapler in an extended position; 
           [0049]      FIG. 35  is a distal end view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler; 
           [0050]      FIG. 36  is a side elevational view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler with the trocar portion of the circular stapler in an extended position; 
           [0051]      FIG. 37  is another side elevational view of the introducer and stapling head of  FIG. 36  with the trocar portion of the circular stapler in a withdrawn position; 
           [0052]      FIG. 38  is a side elevational view of another introducer embodiment of the present invention attached to a stapling head of a circular stapler; 
           [0053]      FIG. 39  is a partial perspective view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler; 
           [0054]      FIG. 40  is another partial perspective view of the introducer embodiment of  FIG. 39  being unwound from the stapling head of the circular stapler; 
           [0055]      FIG. 41  is a partial perspective view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler; 
           [0056]      FIG. 42  is a partial perspective view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler; 
           [0057]      FIG. 43  is another partial perspective view of the introducer of  FIG. 42  being withdrawn proximally from the stapling head of the circular stapler; 
           [0058]      FIG. 44  is a partial perspective view of another introducer embodiment of the present invention attached to the stapling head of a circular stapler; 
           [0059]      FIG. 45  is another partial perspective view of the introducer embodiment of  FIG. 44  wherein a release motion has been initially applied thereto; and 
           [0060]      FIG. 46  is another partial perspective view of the introducer of  FIGS. 44 and 45  illustrating further application of the release motion thereto. 
       
    
    
     DETAILED DESCRIPTION 
       [0061]    The Applicant of the present application also owns the U.S. patent applications identified below which were filed on even date herewith and which are each herein incorporated by reference in their respective entirety:
       U.S. patent application Ser. No. ______, entitled “CIRCULAR STAPLER INTRODUCER WITH RIGID CAP ASSEMBLY CONFIGURED FOR EASY REMOVAL”, Attorney Docket No. END6615USNP/090245;   U.S. patent application Ser. No. ______, entitled “CIRCULAR STAPLER INTRODUCER WITH RADIALLY-OPENABLE DISTAL END PORTION”, Attorney Docket No. END6616USNP/090246;   U.S. patent application Ser. No. ______, entitled “CIRCULAR STAPLER INTRODUCER WITH RIGID DISTAL END PORTION”, Attorney Docket No. END6617USNP/090247; and   U.S. patent application Ser. No. ______, entitled “CIRCULAR STAPLER INTRODUCER WITH MULTI-LUMEN SHEATH”, Attorney Docket No. END6618USNP/090233.       
 
         [0066]    Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the various embodiments of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention. 
         [0067]    The terms “proximal” and “distal” are used herein with reference to a clinician manipulating the handle portion of the surgical instrument. The term “proximal” referring to the portion closest to the clinician and the term “distal” referring to the portion located away from the clinician. It will be further appreciated that, for convenience and clarity, spatial terms such as “vertical”, “horizontal”, “up”, and “down” may be used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and/or absolute. 
         [0068]      FIG. 1  illustrates a conventional circular stapler  10 . The construction and operation of such circular staplers are generally known in the art. Thus, the specific components and features of such circular stapler will not be discussed in detail herein beyond what may be necessary to understand the construction and operation of the various embodiments of the present invention. As the present Detailed Description proceeds, those of ordinary skill in the art will understand that the various embodiments of the present invention may be effectively employed with a variety of different circular stapler configurations without departing from the spirit and scope of the present invention. Accordingly, the scope of protection afforded to the various embodiments of the present invention should not otherwise be limited to use with the exemplary circular stapler depicted herein. 
         [0069]    As can be seen in  FIG. 1 , a conventional circular stapler  10  generally includes a handle portion  12  that has an elongated shaft  14  protruding therefrom. A stapling head  16  is coupled to the distal end  15  of the elongated shaft  14  and is configured to operably support a staple cartridge  17  and movable knife assembly (not shown) therein. The circular stapler  10  further includes an anvil  20  that has an anvil body  22 . The anvil  20  has an anvil shaft  24  that is configured to be removably attached to a trocar (not shown) that is movably supported within the elongated shaft  14  of the circular stapler  10 . Movement of the trocar is achieved by rotating an adjustment knob  18  that is located at the proximal end of the handle portion  12 . An indicator panel  19  may be provided on the handle portion  12  to provide the user with an indication of the position of the body portion  22  of the anvil  20  relative to the staple cartridge  17 . Thus, when the anvil shaft  24  is attached to the movable trocar, the position of the anvil body  22  relative to the staple cartridge  17  in the stapling head assembly  16  may be adjusted by rotating the adjustment knob  18 . The stapling head  16  further supports a staple driver assembly (not shown), the operation of which is controlled by a trigger assembly  26  on the handle portion  12 . Further details concerning the operation and assembly of the exemplary circular stapler  10 , for example, may be gleaned from reference to U.S. patent application Ser. No. 12/408,905, filed Mar. 23, 2009, entitled “Circular Surgical Stapling Instrument With Anvil Locking System” to John P. Measamer, the disclosure of which is herein incorporated by reference in its entirety. 
         [0070]      FIGS. 2-6  illustrate a circular stapler introducer  100  of the present invention that may be used in connection with a circular stapler  10 . In various embodiments, the introducer  100  comprises an elongated hollow flexible sheath  110  that may be fabricated from, for example, a plastic material such as polyurethane blends, polyesters, polyethylene or polypropylene having a thickness of 0.004-0.015 inches and forms a first lumen  29  sized to be readily inserted over the elongated shaft  14  of a circular stapler  10 . The sheath  110  has a distal end  114  and an open proximal end  112  as well as a top portion generally designated as  111  and a bottom portion  113 . See  FIG. 3 . A handle assembly  130  may be attached to the open proximal end  112  by, for example, adhesive or ultrasonic welding, radio frequency (RF) welding or heat staking. The distal end  114  of the sheath  110  may be attached to a rigid cap assembly  130  by adhesive or by ultrasonic welding, radio frequency (RF) welding or heat staking. In various embodiments, a “weakened region” in the form of, for example, a perforated seam  116  may extend along the bottom portion  113  of the sheath  110  from the open proximal end  112  to the distal end  114 . In addition, a second lumen  120  may be formed in the wall of the sheath  110  and extend from the open proximal end  112  to the distal end  114 . In particular, the second lumen  120  may helically extend from the top portion  111  of the proximal end  112  to the bottom portion  113  at the distal end  114 . The second lumen  120  may accommodate a release member  122  that extends from the handle assembly  130  to a latch member  140  that is movably supported in a distal end portion of the second lumen  120 . In various embodiments, the release member  122  may comprise, for example, a suture. In other embodiments, the release member  122  may comprise a relatively thin flexible bar or similar member for transmitting a release motion to the latch member  140  attached thereto. The second lumen  120  may be formed in the wall of the sheath  110  by, for example, sewing, ultrasonic welding, radio frequency (RF) welding, heat staking, etc. The release member  122  and the latch member  140  may collectively form a release arrangement, generally designated as  121 . See  FIG. 10 . 
         [0071]      FIGS. 10-19 , depict a rigid cap assembly  150  that may be used in connection with various embodiments of the present invention. The rigid cap assembly  150  may have a barrel member  152  that is attached to the distal end  114  of the sheath  110 . The barrel member  152  comprises a partial ring-like member that has two opposed ends  154 ,  156 . A rigid cap member  160  is “hingably attached” to the barrel member  152  by a tether  162 . See  FIG. 17 . In various embodiments, the rigid cap assembly  150  is manufactured as a single injection molded piece that has significantly different physical properties. In various embodiments, for example, the rigid cap assembly  150  may be injection molded from polyurethane blends, polyesters, polyethylene or polypropylene. 
         [0072]    As will be discussed in further detail below, the cap member  160  is made rigid by increasing its cross-sectional area while the tether  162  and barrel member  152  are preferably designed to allow significant deflection in specific directions by reducing their respective cross-sections. The cap member  160  has a relatively blunt distal surface  164  that is substantially smooth to minimize the force required to insert the introducer  100  and the portions of the circular stapler  10  housed therein through the patient&#39;s sphincter as well as to facilitate navigation of the device through the Valves of Houston and other anatomy. The underside  166  of the cap member  160  may have a series of reinforcing ribs  168  formed therein to increase its cross-sectional area and make the cap member  160  substantially rigid. See  FIGS. 13 and 19 . 
         [0073]    In various embodiments, the underside  166  of the cap member has a shape that substantially matches the shape of a portion of the perimeter of the stapling head  16 . More specifically and as can be seen in  FIG. 13 , the underside  166 , which is formed by reinforcing ribs  168 , is arcuate in shape which matches a portion of the circular perimetrical shape of the stapling head  16  of the circular stapler  10 . As can be further seen in  FIG. 14 , the cap member  160  has sides  170 ,  172  each has a cutout wall portion  174  that corresponds with the arcuate underside  166 . Such arcuate underside  166  and cutout wall portions  174  enable the cap assembly  150  to pass proximally off the stapling head  16  when being proximally withdrawn over the circular stapler  10  to thereby reduce the radial distention of the bowel when the cap assembly  150  passes by the stapling head  16  of the circular stapler  10 . For example,  FIG. 16  provides an illustrative comparison between a cap assembly  150  with no arcuate underside  166  (represented by dotted line  180 ) and the cap assembly  150  with an arcuate underside  166 . As illustrated, for one exemplary embodiment, the cap assembly without the arcuate underside has a 0.22″ higher profile and would therefore further distend the bowel as it is withdrawn proximally over the stapling head  16 . 
         [0074]    In various embodiments, the tether  162  may be designed to be longer than the distance required to connect the cap member  160  to the barrel member  152  in the closed position ( FIG. 10 ). That is, the tether  162  may coil inside the cap assembly  150  when the rigid cap portion  160  is retained in the closed position. Such arrangement permits the cap member  160  to follow a substantially curved path while passing over the corner of the stapling head  16  of the stapler  10  and to move independently from the barrel member  152  during removal. See  FIGS. 14 and 14A . In one embodiment, the tether  162  is diametrically opposite from the location wherein the latch member  140  engages the opposed ends  154 ,  156  of the barrel member  152 . See  FIGS. 18 and 19 . In an alternative embodiment, the tether  162  is located 90 degrees from the latch  140  member. See  FIGS. 20 and 21 . 
         [0075]    Various embodiments of the cap assembly  150  employ features which work together to ensure that the cap member  160  does not open during the insertion process while retaining the ability to be easily opened and removed at the appropriate time. For example, as can be seen in  FIG. 13 , various embodiments of the cap assembly  150  may include an inwardly-extending retainer flange  190  that is formed on portions of the barrel member  152 . The retainer flange  190  may be positioned to retainingly engage corresponding retention ribs  167  formed on the lower rim of the cap member  160 . As can be seen in  FIG. 13 , a series of gussets  194  may be formed with the retainer flange  190  to further stabilize and rigidify the retention flange  190 . Various cap member embodiments may include at least one retention rib on the cap member  160  to retainingly secure the cap member  160  in a closed position wherein the cap member  160  covers the distal face  25  of the stapling head  16  ( FIG. 10 ). In various embodiments, a series of three ribs  200 ,  202 ,  204  may be formed on the two portions of the cap member  160  that are between the tether  162  and the arcuate cut out portions  174 . The two outer ribs  200 ,  202 ,  204  may be provided with chamfered lead-out portions  206 . See  FIG. 12 . Such chamfered lead out portions  206  interface with the retention flange  190  on the barrel member  152  and may serve to minimize the chances of the cap member  160  binding on the retention flange  190  during the unlatching process without significantly jeopardizing the ability of the rib  167  and retention flange  190  arrangement to carry loads during the insertion process. 
         [0076]    As can be seen in  FIGS. 11 and 12 , the opposed ends  154 ,  156  of the barrel member  152  are spaced from each other to define a latch region  210  for receiving the latch member  140  therein. The latch member  140  may be formed from a plastic material and have a body portion  141  that has a pair of distally protruding latch tabs  142 ,  144  formed thereon. See  FIG. 11 . The latch tabs  142 ,  144  are sized to extend into latch cavities  157 ,  159  formed in the opposing ends  154 ,  156  of the bar  152 . See  FIGS. 10 and 11 . Thus, when the latch tabs  142 ,  144  are received in the latch cavities  157 ,  159 , the barrel member  152  forms a radially-openable ring-like structure sized to accommodate the stapling head  16  of the circular stapler  10  therein. In various embodiments, when the barrel member  152  is latched in the closed position wherein the cap member  160  covers the distal face  25  of the stapling head  16  of the circular stapler  10 , the cap member  160  may sit directly on the distal face  25  of the stapling head  16  of the circular stapler  10  without interfering with any of the staple pockets in the staple cartridge  17  support therein. Such arrangement permits the forces experienced by the cap member  160  during the insertion process to be transmitted directly to the stapling head  16  of the circular stapler  10  without the need for any force balancing or intermediate components. 
         [0077]    Also in various embodiments, the release member  140  may be further formed with a release finger  145  that may serve to assist with radially opening the barrel member  152  when the latch member  140  is pulled proximally out of engagement with the opposed ends  154 ,  156  of the barrel member  152 . More specifically and with reference to  FIG. 11 , the latch member  140  may be formed with a release finger  145  that is centrally disposed between the latch tabs  142 ,  144 . The release finger  145  may be formed with cam portions  147  that are designed to engage cam surfaces  161 ,  163  formed on the opposed ends  154 ,  156  of the barrel member  152  such that, as the latch member  140  is pulled in the proximal direction “P”, the cam portions  147  engage the cam surfaces  161 ,  163  to urge the opposed ends  154 ,  156  of the barrel member  152  radially apart from each other (represented by arrows “R”, in  FIG. 12 ). Thus the latch member  140  is pulled in a direction (proximal direction “P”) that is substantially perpendicular to the direction of motion “R” required to disengage the cap member  160  from the barrel member  152 . When the latch member  140  is removed and the clinician continues to apply an additional withdrawal motion to the introducer  100 , the opposed ends  154 ,  156  of the barrel member  152  are permitted to further radially separate and enable the cap member  160  to disengage from the barrel member  152  and move to an open position. In doing so, the cap member  160  may be permitted to rotate to a lateral open position to facilitate proximal movement of the cap assembly  150  over the stapling head  16  as the introducer  100  is withdrawn proximally from the patient. See  FIG. 14 . 
         [0078]    As can be seen in  FIGS. 7-9 , the handle assembly  130  may be designed to conform to the geometry of the handle portion  12  of the circular stapler  10  when the stapling head  16  has been inserted into the closed cap assembly  150  in a fully inserted position. For example, when a lower rim portion of the rigid cap member  160  is in contact with the distal face  25  of the stapling head  16 , the stapling head  16  may be considered to be in the “fully inserted” position. More broadly, the circular stapler  10  may be considered to be in a fully inserted position when the distal face  25  is in contact with a portion of the rigid cap member  160 . 
         [0079]    In various embodiments, the handle assembly  130  may be configured in such a way as to prevent improper installation of the introducer  100  on the circular stapler  10 . For example, the handle assembly  130  may be “orientation-specific” such that it includes features which mate with corresponding surfaces on the handle portion  12  of the circular stapler  10  when the stapling head has been inserted to the fully inserted position, while at the same time interfering with other surfaces if the introducer  100  is installed incorrectly. In addition, many circular staplers  10  include an indicator panel  19  that is located on the upper side of the handle portion. See  FIG. 1 . Such indicator panel  19  may, for example, provide the clinician with an indication of the position of the anvil  20  relative to the stapling head  16 . In various embodiments, the handle portion  130  of the introducer  100  may be designed to cover or obscure the indicator panel  19  of the circular stapler  10 . Such arrangement serves to ensure that the user is aware that the introducer  100  is installed on the stapler  10  and thereby prevents the user from attempting to fire the circular stapler  10  without first removing the introducer  100 . For example, the handle assembly  130  includes a forward portion  220  that covers or otherwise obscures the indication panel  19  of the circular stapler  10 . 
         [0080]    In various embodiments, the proximal end  124  of the release member  122  or suture is attached to a release slider  230 . As can be seen in  FIG. 6 , the suture  122  may be attached to a forward tab portion  232  of the release slider  230  that is sized to be slidably received within a cavity  222  formed in the forward portion of the handle assembly  130 . The forward tab portion  232  is slidably retained within the cavity  222  by a cover  240  that may be attached to the handle assembly  130  by a series of retainer tabs  242  that are oriented to snappingly engage corresponding snap cavities  224  in the handle assembly  130 . See  FIGS. 5 and 6   
         [0081]    Various embodiments of the present invention may also incorporate a means for multiplying a proximal travel distance of the suture  122  relative to a distance that the release slider  230  is moved on the handle portion  12  of the circular stapler  10 . For example, various embodiments may employ a pulley-type arrangement  250  to multiply the travel distance of the suture  122  relative the distance that the release slider  230  is moved in the proximal direction “P”. Such arrangement may allow for greater travel to ensure the release of the cap member  160  without the need to lengthen the handle portion  130 . For example, as shown in  FIG. 6 , the proximal end portion  124  of the suture  122  extends through a slot  252  in the handle assembly  130  and loops through a hole  234  in the forward slider tab  232 . The end  124  of the suture  122  may then be attached to a fixed post  254  on the handle assembly  130   
         [0082]    To facilitate easy removal of the introducer  100 , the release slider  230  may be provided with a relatively “low profile” to enable the clinician to maintain a grip on the handle portion  12  of the stapler  10  without significantly changing their grip or method from what they would do with the circular stapler  10  alone. See  FIGS. 7-9 . Also, in various embodiments, the release slider  230  may be provided with a hole  236  and/or two lateral wing portions  238 . Thus, this arrangement allows the clinician to apply force to the release slider  230  in the proximal direction “P” using either a single finger in the hole  236  or two fingers on the lateral wing portions  238 . 
         [0083]    As can also be seen in  FIG. 6 , the forward portion  220  of the handle assembly  130  may also be provided with stops  229  that are arranged to engage forward tabs  239  formed on the forward tab portion  232  of the release slider  230 . Thus, in use, once the circular stapler  10  has been inserted into the introducer  100  to the fully inserted position and the stapler  10  and introducer  100  have been inserted to a desired position within the patient, the clinician may then pull the release slider  230  in a proximal direction to apply an amount of tension or release motion to the suture  122  to draw the latch member  140  to an unlatched position. Further pulling on the release slider  230  will result in the forward tabs  239  contacting the stops  229 . Once the forward tabs  239  contact the stops  229 , further pulling of the release slider  230  in the proximal direction causes the entire introducer  100  to move in the proximal direction. Such arrangement enables the entire introducer  100  to be decoupled from the stapler  10  and withdrawn from the patient by moving the release slider  230  in the proximal direction on the handle portion  12  of the circular stapler  10 . The removal of the introducer  100  from the stapler  10  may be accomplished without removing the stapler  10  from the patient. 
         [0084]    To use the introducer  100 , the clinician simply inserts the circular stapler  10  into the sheath  110  to the fully inserted position and aligns the introducer  100  relative to the handle portion  12  such that the forward portion  220  of the handle portion  130  covers the indication panel  19  of the circular stapler  10 . To aid in the insertion process, the stapling head  16  and shaft portion  14  of the circular stapler  10 , as well as the cap assembly  150  and sheath  110  of the introducer  100 , may be lubricated prior to commencing the insertion process. When the circular stapler  10  has been properly inserted into the introducer  100 , the rim of the cap  160  which is engaged with the flange  190  of the barrel assembly  152  and thereby retained in the closed position as illustrated in  FIGS. 3-6 ,  10  and  13 , will rest on the stapling head  16  of the stapler  10 . The user then inserts the stapler  10  and introducer  100  into a desired position in the colon. Once the stapler  10  is in a desired position, the clinician may pull on the release slider  230  in the proximal direction “P” which causes the suture  122  to pull the retainer latch  140  out of engagement with the ends  154 ,  156  of the barrel assembly  152 . As the retainer latch  140  is drawn proximally, the cam surfaces  147  on the release finger  145  cooperate with the cam surfaces  161 ,  163  formed on the opposed ends  154 ,  156  of the barrel assembly  152  such that, as the release member  140  is pulled in the proximal direction “P”, the ends  154 ,  156  are urged radially apart. Further pulling of the release slider  230  results in the forward tabs  232  contacting the stops  229  such that further pulling of the slider  230  results in the entire introducer  100  being pulled proximally over the circular stapler  10 . Such pulling of the introducer  100  may cause the sheath  110  to separate along the line of perforations  116  and the cap  160  to move to an open position ( FIGS. 14 and 15 ) to thereby enable the introducer  100  to be withdrawn from the patient prior to firing the stapler  10 . 
         [0085]      FIG. 22  illustrates another introducer  300  of the present invention. In this embodiment, the introducer  300  comprises a hollow sheath  302  that has a closed end  304  and an open end  306  for insertion onto the circular stapler  10 . The sheath  302  may be fabricated from a flexible material such as from those materials commonly employed to fabricate condoms. In one embodiment, the sheath  302  is fabricated from a single piece of material that has an elongate seam  310  that extends the length of the sheath  302 . In particular, the sheath material is folded over such that the end  312  of the material overlaps end  314  of the material represented by distance “O” in  FIG. 22 . The ends  312 ,  314  are then stitched together by a suture  316  forming the seam  310 . Thus, the sheath  302  is inserted over the stapling head  16  of the stapler  10  prior to insertion into the patient. After the stapler  10  and sheath  302  have been inserted into position, the sheath  302  may be removed by pulling the suture  316  to thereby release the seam  310  to permit the sheath  302  to be removed. In other embodiments, the sheath  302  is fabricated from two pieces of flexible material that are stitched together with two sutures  316  in the manner described above. To remove the sheath  302 , the clinician simply pulls on one or both of the sutures  316 . 
         [0086]      FIG. 23  illustrates another introducer  320  of the present invention. In this embodiment, the introducer  320  comprises a hollow sheath  322  that has a closed end  324  and an open end  326  for insertion onto the circular stapler  10 . The sheath  322  may be fabricated from a flexible material such as that material commonly employed to fabricate condoms. In one embodiment, the sheath  320  has a closed end  342  and an open end  326  and is provided with at least one weakened area  328  which may comprise a perforated line or seam that extends the length of the sheath  322 . Thus, the sheath  322  is inserted over the stapling head  16  of the stapler  10  prior to insertion into the patient. After the stapler  10  has been inserted into position, the sheath  322  may be removed by pulling on the weakened area  328  to permit the sheath  322  to be separated from the stapler  12 . 
         [0087]      FIGS. 24-28  illustrate another introducer  330  of the present invention. In this embodiment, the introducer  330  comprises a sheath  332  that has a closed distal end  334  and an open proximal end  336  that is sized to be stretched over at least a distal portion of the stapling head  16  of the circular stapler  10 . The sheath  332  may be fabricated from, for example, silicone, latex or other relatively low durometer material (i.e., a durometer of 90 A). In various embodiments, a circumferentially-extending raised bumper area  338  may be formed around the circumference of the closed distal end  334  as shown in  FIGS. 24 and 25 . In some embodiments, a central portion  335  extends inwardly from the circumferentially-extending bumper area  338  to enclose an open central area  27  in the stapling head  16 . See  FIG. 25 . 
         [0088]    As can also be seen in  FIG. 25 , the bumper area  338  extends distally beyond (or in other words is “raised above”) a plane D-D defined by a distal face  25  of the stapling head  16 . In some embodiments, the bumper area  338  is formed from solid material. See  FIG. 26 . In other embodiments, a circumferentially-extending hollow area  340  is formed therein. In other embodiments, hollow area  340  comprises a plurality of pockets  341 . See  FIG. 28 . The area  340  and pockets  341  may be filled with air or a liquid such as saline solution for example. In use, the sheath  332  is rolled over the stapling head  16  of the stapler  10 . The sheath  332  may be left in place while closing and firing the stapler  10  in which case the area  340  or pockets  341  would be broken leaving only the sheath material behind under the staple crown inside the rectal lumen. 
         [0089]      FIG. 29  illustrates another introducer  350  of the present invention. In this embodiment, the introducer  350  comprises a sheath  352  that has a distal end  354  and an open proximal end  356  that is sized to be stretched over the stapling head  16  of the circular stapler  10 . The sheath  352  may be fabricated from, for example, silicone, latex or other relatively low durometer material (i.e., a durometer of 90 A). In various embodiments, a circumferentially-extending raised bumper area  357  may be formed around the circumference of the sheath  352  such that it covers the distal face  25  of the stapling head  16  and a portion  359  extends into the central open area  27  and below the plane D-D defined by the distal face  25 . See  FIG. 29 . In some embodiments, the bumper area  357  is formed from solid material. In other embodiments, a circumferentially-extending hollow area  358  is formed therein. The hollow area  358  may be filled with air or a liquid such as saline solution. In other embodiments, the circumferentially extending hollow area  358  is segmented (e.g., comprises a series of discrete pockets that extend around the circumference of the sheath  352 ). The discrete pockets may be filled with air or liquid such as saline solution for example. In use, the sheath  352  is rolled over the distal end portion of the stapling head  16 . The sheath  352  may be left in place while closing and firing the stapler  10  in which case the hollow area  358  or pockets would be broken leaving only the sheath material behind under the staple crown inside the rectal lumen. 
         [0090]      FIGS. 30-32  illustrate another introducer  360  of the present invention. In this embodiment, the introducer  350  comprises a cover  362  that is sized to be installed on at least a distal portion of the stapling head  16 . In one embodiment, the cover  362  comprises a “C”-shaped body portion  363  that may be fabricated from, for example, polyurethane blends, polyesters, polyethylene, polycarbonate or polypropylene and be sized to be snapped onto the stapling head  16  and portion of the elongated shaft  14  of the circular stapler  10 . See  FIG. 31 . In various embodiments, the distal end  364  of the body portion  363  has at least three normally closed fingers  366  that, when moved distally on the stapling head  16 , close together forming, for example, a “tulip-like” shape for insertion into the anus. See  FIG. 30 . The body portion  363  may have a retraction member  370  formed thereon for facilitating the application of a retraction motion thereto. When the stapler  10  has reached its targeted insertion point, the cover  362  may be pulled toward the handle portion  12  of the stapler  10 , thus pulling the fingers  366  to the vertical sides of the stapling head  16  exposing the distal face  25  of the staple cartridge  17 . See  FIG. 32 . 
         [0091]      FIGS. 33 and 34  illustrate another introducer  380  of the present invention. In this embodiment, the introducer  380  comprises a cover  382  that includes four fingers  384  that extend from a centrally disposed hub  386  that has a trocar access hole  388  therethrough. The proximal end  390  of each of the fingers  384  has a retention flange  392  formed thereon that extend into the central opening  27  and engage the central wall portion  21  of the stapling head  16 . To install the cover  382 , the cover  382  is positioned over the stapling head  16  as shown in  FIGS. 33 and 34  and the trocar  23  of the circular stapler  10  is advanced such that the distal end portion  35  of the trocar  23  protrudes through the hole  388  in the central hub  386 . Once in position, the trocar  23  is retracted proximally into central opening  27  to thereby force the fingers  384  into a generally bulbous, “mushroom-like” cross-sectional shape. Once the stapler  10  is positioned in the rectum, the trocar  23  can then be deployed and pushed thru the rectal wall allowing access to the accessory fingers  384  which can be removed from the trocar  23 . 
         [0092]      FIGS. 35-37  illustrate another introducer  400  of the present invention. In this embodiment, the introducer  400  comprises a cover  402  that include four fingers  404  that are attached together by a sheath  410 . See  FIG. 35 . The sheath may be made from, for example, silicone material. The apex area  412  of the sheath  410  may have a trocar access hole  414  therethrough. The proximal end  406  of each of the fingers  404  has a retention flange  408  formed thereon that extend into the central opening  21  in the stapling head  16 . To install the cover  400 , the cover  402  is positioned over the stapling head  16  as shown in  FIGS. 35 and 36  and the trocar  23  of the circular stapler  10  is advanced distally such that the distal end portion  35  of the trocar  23  protrudes through the hole  414  in the sheath  410 . Once in position, the trocar  23  is retracted to thereby force the fingers  404  into a generally mushroom cross-sectional shape. See  FIG. 37 . Once the stapler  10  is positioned in the rectum, the trocar  23  can then be deployed and pushed thru the rectal wall allowing access to the accessory fingers  404  which can be removed from the trocar  23 . 
         [0093]      FIG. 38  illustrates another introducer  420  that may be fabricated from, for example, polyurethane blends, polyesters, polyethylene, polycarbonate or poly propylene that has at least four fingers  422  that are interconnected at a hub or apex area  424 . The proximal ends  426  of the fingers  422  snap onto the stapling head  16 . In this embodiment, the introducer  420  is designed to go up the colon and then be removed. This is unlike the introducer  400  described above wherein the trocar is in the extended position to hold it in place until the device is in position and then the trocar is brought proximally. 
         [0094]      FIGS. 39 and 40  illustrate another introducer  500  that may be used in connection with a circular stapler  10 . As can be seen in those Figures, the introducer  500  may comprise a molded arrangement with perforations and may be fabricated from, for example, polyurethane blends, polyesters, polyethylene or polypropylene or alternatively could comprise wound strip that is sewn together or held in place without covering. The strip  504  may have a width of, for example, 0.250 inches and a thickness of, for example, 0.020 inches. The strip  504  may form a base portion  506  sized to extend around the circumference of the stapling head  16 . The base portion  506  may be sized relative to the stapling head  16  such that, when held together in close spiral relationship, the spiral strip  504  forms a relatively tight (interference) fit with the stapling head  16  to retain the introducer thereon. The spirally wound strip  504  forms a plurality of successive passes  508  that tapers to a blunt distal end  510 . As can be seen in  FIG. 36 , one embodiment resembles a blunt-ended “beehive-shape” that substantially encloses or covers the distal face of the stapling head  16 . The spiral passes  508  may be held in substantial abutting relationship (i.e., spirally wound closed ended relationship) by a retainer member  510 . In various embodiments, the retainer member  510  may comprise a thin (e.g., 1 to 4 Mils) layer of shrink wrap that extends over the introducer  500 . The introducer  500  also includes a release member  520  that is attached to the strip material  504  such that upon application of a release motion thereto, the spiral wound strip member  504  is unwound from engagement with the distal portion of the stapling head  16 . In one embodiment, for example, the release member comprises a release suture  520  that is attached to the distal end  512  of the strip  504 . The release suture  520  may pass through a hole  522  in a portion of the strip  504  forming the base portion  506  and extend proximally out to the handle portion of the stapler  10  to enable the release suture  520  to be grasped by the clinician. 
         [0095]    The introducer  500  may be installed by the supplier of the stapler  10  by shrink wrapping the introducer  500  to the stapling head  16 . In use, the clinician inserts the stapler and introducer assembly  530  into the patient&#39;s anus and past the Valves of Houston to the desired area. Once the clinician has determined that the stapler  10  is in the desired position, the clinician can then pull the release suture  520  in the proximal direction “P” which causes the shrink wrap  510  to rupture thereby permitting the introducer  500  to unwind as illustrated in  FIG. 40 . Continued pulling on the release suture  520  will enable the introducer  500  to be withdrawn from the patient. 
         [0096]      FIGS. 41-43  illustrate another introducer  600  that may be used in connection with a circular stapler  10 . As can be seen in those Figures, the introducer  600  may have a base portion  602  sized to be retained on the stapling head  16 . The introducer  600  is formed with a plurality of tapered “petal” portions  504  that taper to a substantially rounded point  606 . In some embodiments, for example, there are four diametrically opposed petal portions  604  that, when closed ( FIG. 41 ), converge to form a relatively blunted pointed end  610 . The petal portions  604  have an open area  612  therebetween. In various embodiments, the petal portions  604  are retained in the closed position by a releaseable retainer member  620 . In some embodiments for example, the retainer member comprises shrink-wrap material  620  that is applied around the introducer  600 . In some embodiments, a plurality of retention ledges  630  may be formed around the inner perimeter of the base  602  to engage the distal face  25  of the stapling head  16  when the shrink wrap  620  has been applied. Release sutures  640  may be sewed through those portions  622  of the shrink-wrap  620  that cover the open area  612 . The release sutures  640  terminate in or are each attached to a release suture  650  that passes through a hole  652  in the base portion  602  and extends proximally out to the handle portion of the stapler  10  to enable the release suture  650  to be grasped by the clinician. 
         [0097]    The introducer  600  may be installed by the supplier of the stapler  10  by shrink wrapping the introducer  600  to the stapling head  16 . In use, the clinician inserts the stapler and introducer assembly  660  into the patient&#39;s anus and past the Valves of Houston to the desired area. Once the clinician has determined that the stapling head of the stapler  10  is in the desired position, the clinician can then pull the release suture  650  in the proximal direction “P” which causes the shrink-wrap  620  to rupture thereby permitting the introducer  600  to be pulled distally over the stapling head  16  as illustrated in  FIG. 43 . 
         [0098]      FIGS. 44-46  illustrate another introducer  700  that may be used in connection with a circular stapler  10 . As can be seen in those Figures, the introducer  700  may be fabricated from, for example, polyurethane blends, polyesters, polyethylene or polypropylene and have a base portion  702  sized to be retained on the stapling head  16 . The introducer  700  is formed with a plurality of tapered “segment” portions  704  that taper to a substantially rounded point  706 . In some embodiments, for example, there are four diametrically opposed segment portions  604  that, when closed ( FIG. 44 ), converge to form a relatively blunted pointed end  710 . In the embodiment depicted in  FIGS. 44-46 , the introducer  700  includes four segment portions  704 . The segment portions  704  are interconnected at their base portions except for two adjacent segment portions  704  wherein the bases of the two segment portions  704  are not attached together. More particularly, segment portion  704 A has a base edge  705 A and segment portion  704 B has a base edge  705 B. Edges  705 A and  705 B are not attached to each other. Thus, segment portion  704 A and segment portion  704 B comprise free ends of the base portion  702 . The free ends  704 A and  704 B are retained in abutting relationship by a retainer member in the form of a radial release tab  720  that is attached to  704 A and  704 B. In various embodiments, the release tab  720  is fixed or molded to segment portion  704 A and may not necessarily be removed therefrom. The release tab  720  is releaseably attached to segment portion  704 B. The release tab  720  may be attached to the segment portion  704  by a releasable retainer  722  such as, for example, a releasable adhesive or piece of rupturable material. When the release tab  720  is attached as shown in  FIG. 41 , the segment portions  704  form an annular base portion  702  that may be retainingly snapped onto or other wise retainingly engage the stapling head  16  of the circular stapler  10 . A release suture  730  is attached to the release tab  720  and extends proximally out to the handle portion  12  of the stapler  10  to enable the release suture  730  to be grasped by the clinician. 
         [0099]    The introducer  700  may be snapped onto or pressed onto the stapling head  16  by the clinician. In use, the clinician inserts the stapler and introducer assembly  740  into the patient&#39;s anus and past the Valves of Houston to the desired area. Once the clinician has determined that the stapling head  16  of the stapler  10  is in the desired position, the clinician can then pull the release suture  730  in the proximal direction “P” which causes the release tab  720  to release from the segment portion  704 B to enable the introducer  700  to release from the stapling head  16 . Continued pulling on the release suture  730  will enable the introducer  700  to be withdrawn from the patient. 
         [0100]    Thus, the various embodiments of the circular stapler introducer of the present invention may facilitate the transanal and transabdominal insertion and navigation to access the staple line of the distal stump in lower anterior resections. The various introducers may be provided as a part of a kit that also includes a circular stapler  10 . Various embodiments of the introducer will have no impact on the current functions of the circular stapler. 
         [0101]    The various embodiments of the present invention represent a vast improvement over prior circular staple arrangements that fail to provide any means for locking the anvil in a firing position. While several embodiments of the invention have been described, it should be apparent, however, that various modifications, alterations and adaptations to those embodiments may occur to persons skilled in the art with the attainment of some or all of the advantages of the invention. For example, according to various embodiments, a single component may be replaced by multiple components, and multiple components may be replaced by a single component, to perform a given function or functions. This application is therefore intended to cover all such modifications, alterations and adaptations without departing from the scope and spirit of the disclosed invention as defined by the appended claims. 
         [0102]    Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. 
         [0103]    The invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. The embodiments are therefore to be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such equivalents, variations and changes which fall within the spirit and scope of the present invention as defined in the claims be embraced thereby.