Abstract:
An exemplary surgical apparatus may include an anvil including an outer surface, a channel defined therein, and an aperture defined in the outer surface, where the aperture opens to the channel; and a cutter slidable along and within the channel, where at least a portion of the cutter is flexible. Another exemplary surgical apparatus may include an anvil including an open channel defined therein; and a one-piece cutter including a knife adjacent to a bending region, where the cutter is slidable in the channel; where the knife is initially held completely within the anvil, and where the knife flexes out of the channel and out of the anvil in response to proximal motion of the cutter. An exemplary surgical method of treating tissue within the body of a patient may include providing a flexible cutter including a knife; providing an anvil with a channel defined therein; holding the knife completely within the channel in a stowed position; placing the anvil adjacent to tissue; and moving the cutter proximally, wherein that moving causes at least part of the knife to flex out of the channel and into the tissue adjacent to the anvil.

Description:
FIELD OF THE INVENTION 
     The invention generally relates to surgical staplers, and more specifically to cutters utilized in surgical staplers to cut tissue. 
     BACKGROUND 
     Surgical staplers, such as utilized in anastomosis procedures, transection of tissue, and other procedures, generally include one or more staples and an anvil against which those staples are deformed. Surgical staplers often additionally include a knife that is used to cut tissue after, during or before staples are deployed adjacent to that tissue. For example, U.S. Pat. No. 7,285,131 and U.S. patent application Ser. No. 11/935,315 filed on Nov. 5, 2007, both of which are hereby incorporated by reference in their entirety (the “Anvil Documents”) describe an anvil sized for placement in a target blood vessel, where staples are deployed from outside the coronary artery against the anvil to connect a graft vessel to the target vessel. The anvils disclosed in the Anvil Documents each include a knife, and a channel along which the knife can slide. The knife is initially in a first position stowed inside the anvil, then moves to a position above the anvil in order to cut the wall of the target vessel and allow blood to flow between the graft vessel and the target vessel, thereby completing the anastomosis. The knife is then moved back to a second position stowed within the anvil, different from the first position. The Anvil Documents describe single-user tools that cannot be refired. One reason is that the first and second stowed positions of the knife within the anvil are different. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cutaway perspective view of an exemplary anvil in which an exemplary cutter is located in a first position. 
         FIG. 2  is a cutaway perspective view of the anvil of  FIG. 1 , in which the cutter is located in a second position. 
         FIG. 3  is a cutaway perspective view of the anvil of  FIG. 1 , in which the cutter is located in a third position. 
         FIG. 4  is a cutaway perspective view of the anvil of  FIG. 1 , in which the cutter is located in a fourth position. 
         FIG. 5  is a side view of the cutter of  FIG. 1 . 
         FIG. 6  is a perspective view of the cutter of  FIG. 1 . 
         FIG. 7  is a side view of another exemplary cutter. 
     
    
    
     The use of the same reference symbols in different figures indicates similar or identical items. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a surgical stapler includes an anvil  2 . Staples may be driven against the anvil  2  by any suitable staple holder, such as described in the Anvil Documents; the particular stapling mechanism utilized is not important to the invention. The anvil  2  may be generally elongated in the longitudinal direction, or may be shaped in any other suitable manner. The anvil  2  includes an upper surface  4 , and a longitudinally-extending aperture  6  defined through the upper surface  4 . The aperture  6  opens to a channel  8  as seen most clearly in  FIG. 3 . The channel  8  may include a proximal section  10  and a distal section  12  open to one another. The proximal section  10  may be smaller in cross-sectional area than the distal section  12 , and may have a generally-rectangular cross-section along a plane perpendicular to the longitudinal centerline of the anvil  2 . Alternately, the proximal section  10  may be shaped in any other suitable manner. The distal section  12  may be roughly triangular in shape, as viewed from the side, or may be shaped in any other suitable manner. The distal section  12  is shaped and sized to hold a knife in a stowed position. 
     Referring also to  FIGS. 5-6 , a cutter  14  is configured to slide along the channel  8 . The cutter  14  may include a knife  16  at the distal end of an arm  18 . The arm  18  may be generally linear along part or most of its length, and may have a rectangular cross-section or other suitable cross-section. The proximal section  10  of the channel  8  may have a cross-section shaped the same as the cross-section of the arm  18 . The proximal section  10  of the channel  8  also may be slightly larger in size than the cross-section of the arm  18 , in order to allow the arm  18  to slide within the proximal section  10  of the channel  8  while at the same time constraining motion of the arm  18  in directions other than longitudinally. The proximal end of the arm  18  may be connected to a cable, rod or other structure or mechanism that is used to move the cutter  14  along the channel  8 . Such a connection may be accomplished, for example, as set forth in the Anvil Documents. The distal end of the arm  18  may be curved or bent downward, resulting in a curved region  20  at the distal end of the arm. The arm  18  may include a wide area  22  immediately proximal to the curved region  20 , where the wide area  22  is wider laterally than the portion of the arm  18  proximal to the wide area  22 . Alternately, the wide area  22  may be wider in a different direction, or may be omitted. The curved region  20  may taper downward in width in the distal direction along part or all of its length. As a result, the cross-sectional area of the curved region  20  may decrease moving distally along the curved region. The tapered area of the curved region  20  may be referred to as the bending region  24 . The knife  16  may extend from the distal end of the curved region  20 . The knife  16  may be generally perpendicular to the part of the curved region  20  from which it extends, or may be angled differently relative to the curved region  20 . The knife  16  may extend from a lateral edge of the curved region  20 . If so, the portion of the curved region  20  laterally adjacent to the knife  16  may be referred to as the ledge  36 . Further, the knife  16  may form an obtuse angle  26  with the upper surface of the arm  18 . The knife  16  includes a cutting edge  30  that is oriented generally upward. The opposite side  32  of the knife  16  may be blunt. The shape of the cutter  14  described here and shown in  FIGS. 5-6  is the shape assumed by the cutter  14  in a neutral state. The “neutral state” means the state in which no external forces are acting upon the cutter  14 . Alternately, the shape of the cutter  14  shown in  FIGS. 5-6  may be the deformed shape of the cutter  14  that the cutter  14  assumes when forced into an initial position. 
     The cutter  14  may be fabricated as a single piece, such as by stamping, molding, laser cutting, machining, or any other suitable process or combination of processes. Alternately, the knife  16  may be fabricated separately from the arm  18  and attached to the arm  18  by any suitable method or structure, such as by welding. The cutter  14  may be fabricated from any suitable material. Advantageously, the cutter  14  is fabricated from a superelastic alloy such as nitinol. As another example, the cutter  14  may be fabricated from an elastically deformable material. Such material may be, for example, an amorphous zirconium-based metal alloy such as Vitreloy. As another example, the cutter  14  may be composed of a plastically-deformable material, where bending in the bending region  24  causes stress in the cutter  14  that is less than the yield point of the material from which the cutter  14  is fabricated. 
     Referring also to  FIG. 1 , the cutter  14  is in its initial position within the anvil  2  such that the majority of the arm  18  is located in the proximal section  10  of the channel  8 , and the knife  16  and the curved region  20  of the arm  18  are located in the distal section  12  of the channel  8 . In the initial position of the cutter  14  within the channel  8 , the knife  16  is located entirely within the channel  8 . When the cutter  14  is in the initial position, the knife  16  may be referred to as being in the initial position or as being in the stowed position. The knife  16  does not extend out of the aperture  6  in the upper surface  4  of the anvil  2  in the initial position of the cutter  14 . In this way, the anvil  2  can be inserted into tissue without the risk of the knife  16  cutting that tissue. The anvil  2  may include a cam surface  34  defined in the distal section  12  of the channel  8 . The cam surface  34  may be curved downward proximally to distally, or may be shaped in any other suitable manner. When the cutter  14  is in the initial position completely within the channel  8  in the anvil  2 , the cam surface  34  engages the ledge  36  of the curved surface  20  of the cutter  14 , and/or a remainder of the curved surface  20 . This contact between the cam surface  34  and the ledge  36  and/or a remainder of the curved surface  20  may push the knife  16  downward relative to its neutral state, such that the obtuse angle  26  between the arm  18  and the knife  16  is greater than in the neutral state. Alternately, the cam surface  34  and the cutter  14  are configured such that the cutter  14  is in the neutral state when in the initial position in the channel  8  in the anvil  2 . 
     Operation 
     Placement of the anvil  2  relative to tissue, and actuation of the cutter  14 , may be substantially as described in the Anvil Documents. For clarity and brevity, the differences between that operation described in the Anvil Documents and the operation of the cutter  14  of this document are described here. The anvil  2  is placed in proximity to tissue to be treated, such as inside the lumen of a target vessel. The cutter  14  is then actuated, such as by depressing a firing trigger on a handle. 
     Referring also to  FIG. 1 , upon actuation of the cutter  14 , the arm  18  is pulled proximally. The knife  16  moves proximally as well. The ledge  36  adjacent to the knife  16  slides proximally, along the cam surface  34 . As the knife  16  moves proximally, it also moves upward, as the curved region  20  of the arm  18  relaxes into its neutral state. As the knife  16  moves upward, the cutting edge  30  of the knife  16  moves upward through and out of the aperture  6  in the channel  8 . That is, the knife  16  flexes upward through and out of the aperture  6 , as the force previously holding the knife  16  down in the stowed position is gradually removed. As the cutting edge  30  moves out of the aperture  6 , it penetrates tissue adjacent to the upper surface  4  of the anvil  2 . As the ledge  36  moves proximally and upward along the cam surface  34 , the curved region  20  of the arm  18  may relax into its neutral state, such that the obtuse angle  26  between the knife  16  and the upper surface of the arm  28  decreases. As the ledge  36  then continues to move proximally and upward along the cam surface  34 , the curved region  20  of the arm  18  enters the proximal section  10  of the channel  8 . The entry of the curved region  20  into the generally-rectangular proximal section  10  of the channel  8  causes the curved region  20  to bend into a straighter shape, causing the obtuse angle  26  between the knife  16  and the upper surface  28  of the arm  18  to decrease further. Referring also to  FIG. 2 , when the curved region  20  of the arm  18  has completely entered the proximal section  10  of the channel  8 , the knife  16  has moved upward out of the aperture  6  to its maximum extent, which may be referred to as the cutting configuration of the knife  16 . In the cutting configuration, the obtuse angle  26  between the knife  16  and the upper surface of the arm  28  may be substantially a right angle, or slightly greater than a right angle. Alternately, the obtuse angle  26  may become an acute angle in the cutting configuration. 
     The arm  18  continues to be pulled proximally. As a result, the knife  16  moves proximally. The cutting edge  30  faces proximally, such that proximal motion of the knife  16  creates an incision in the tissue previously penetrated by the knife  16  when the knife  16  moved up and out of the aperture  6  in the upper surface  4  of the anvil  2 . The arm  18  continues to move proximally until it stops. Proximal motion of the arm  18  may stop due to an encounter between the knife  16  and the proximal end  38  of the aperture  6 , due to cessation of actuation of the cutter  14  in the proximal direction, or a combination of both. Referring also to  FIG. 3 , the knife  16  is then in the most-proximal location, and the incision of tissue adjacent to the upper surface  4  of the anvil  2  is complete. Before, during and/or after motion of the knife  16  to the most-proximal location, staples may be deployed into the tissue adjacent to the upper surface  4  of the anvil  2  as set forth in the Anvil Documents, or that tissue may be otherwise treated. 
     The cutter  14  is then actuated to move distally. Referring also to  FIG. 4 , the knife  16  consequently moves distally from its previous, most-proximal location. As the knife  16  moves distally, its blunt side  32  leads, such that the blunt side  32  of the knife  16  does not further incise tissue during distal travel of the knife  16 . As the knife  16  continues to move distally, the ledge  36  at the distal end of the curved region  20  of the arm  18  slides under the proximal end of the cam surface  34 . As the cutter  14  continues to move distally, the curved region  20  of the arm  18  begins to move out of the proximal section  10  of the channel  8 , allowing the cutter  14  to return toward its neutral state. Further, engagement between the cam surface  34  and the ledge  36  urges the cutter  14  to move back toward its neutral state. As the cutter  14  returns toward its neutral state, the obtuse angle  26  between the knife  16  and the upper surface  28  of the arm  18  increases. After the cutter  14  returns to its neutral state, the cutter  14  may still continue to be urged distally if the knife  16  has not reached its initial position. Contact between the ledge  36  and the cam surface  34  causes the curved region  20  to bend such that the obtuse angle  26  between the knife  16  and the upper surface  28  of the arm  18  increases further. The cutter  14  moves distally until the knife  16  reaches its initial position, completely within the channel  8  in the anvil  2 . The anvil  2  can then be removed from tissue, or reused within the same tissue. By returning the cutter  14  to its initial position after it has incised tissue, the cutter  14  can be actuated multiple times from that initial position. 
     Reverse Knife 
     Referring to  FIG. 7 , another exemplary embodiment of the cutter  14  is shown. In this embodiment, the knife  16  forms an acute angle  40  with the upper surface  28  of the arm  18  in the neutral state. The cutting edge  30  extends onto the top of the knife  16 . Further, the curved region  20  is not present in this embodiment; however, the bending region  24  is present, and the arm  18  is tapered in the bending region. In other respects, the cutter  14  is as set forth above. The anvil  2  is also substantially as set forth above, with the exception that the cam surface  34  can be eliminated. 
     Operation of this embodiment of the cutter  14  is substantially as described above. For clarity and brevity, the differences between that operation and the operation of the cutter  14  of  FIG. 7  are described here. The distal portion  12  of the channel  8  extends distal to the distal end of the aperture  6 , and the knife  16  is located in that distal portion  12  of the channel  8  in the initial position of the cutter  14 . The distal portion  12  of the channel  8  compresses the knife  16  down. As the cutter  14  is pulled proximally, the knife  16  is free to move upward to its neutral position. As the knife  16  moves upward, the cutting edge  30  on the upper surface of the knife  16  penetrates tissue adjacent to the upper surface  4  of the anvil  2 . As described above, as the cutter  14  is moved proximally, the cutting edge  30  of the knife  16  incises tissue adjacent to the upper surface of the anvil  2 . The cutter  14  is then moved distally. As the blunt side  32  of the knife  16  encounters the distal end of the aperture  6 , that contact pushes the knife  16  downward, and the knife  16  moves downward and slides into the distal portion  12  of the channel  18  distal to the aperture  6 . The knife  16  has thus returned to its initial, stowed position. 
     While the invention has been described in detail, it will be apparent to one skilled in the art that various changes and modifications can be made and equivalents employed, without departing from the present invention. It is to be understood that the invention is not limited to the details of construction, the arrangements of components, and/or the method set forth in the above description or illustrated in the drawings. Statements in the abstract of this document, and any summary statements in this document, are merely exemplary; they are not, and cannot be interpreted as, limiting the scope of the claims. Further, the figures are merely exemplary and not limiting. Topical headings and subheadings are for the convenience of the reader only. They should not and cannot be construed to have any substantive significance, meaning or interpretation, and should not and cannot be deemed to indicate that all of the information relating to any particular topic is to be found under or limited to any particular heading or subheading. Therefore, the invention is not to be restricted or limited except in accordance with the following claims and their legal equivalents.