SURGICAL STAPLER, ANVIL FOR A SURGICAL STAPLER, AND A METHOD OF STAPLING TISSUE

Abstract

A surgical stapler includes a proximal end and a distal end and an anvil at the distal end for providing resistance to staples during the stapling operation of the surgical stapler. The anvil may include a number of segments arranged end-to-end. The anvil is elongated in the collapsed state, the anvil being elongated generally in a first direction D1. The anvil is configured such that the segments rotate about a rotation axis along a perpendicular second direction D2 when the anvil is actuated between the deployed and the collapsed states. The anvil is configured such that adjacent segments pivot relative to each other about a pivot axis along a third direction D3 when the anvil is actuated between the deployed and collapsed states. The stapler also includes an actuator mechanism, wherein the actuator mechanism is configured to be controlled from a location on the surgical stapler towards the proximal end.

Claims

1. An anvil for providing resistance to staples during the stapling operation of a surgical stapler, the surgical stapler comprising a proximal end and a distal end wherein the proximal end is proximate to the user in use and the distal end is distal from the user in use: wherein the anvil is locatable at the distal end of the surgical stapler, wherein the anvil is configured to be actuated between a deployed state and a collapsed state, wherein the anvil comprises a plurality of segments arranged end-to-end, wherein the anvil is elongated in the collapsed state, the anvil being elongated generally in a first direction, wherein the area covered by the anvil is greater in the deployed state than the collapsed state when viewed along the first direction, wherein the anvil is configured such that the segments rotate about a rotation axis along a second direction perpendicular to the first direction when the anvil is actuated between the deployed and the collapsed states, and wherein the anvil is configured such that adjacent segments pivot relative to each other about a pivot axis along a third direction perpendicular to the second direction when the anvil is actuated between the deployed and collapsed states.

2. An anvil as claimed in claim 1, wherein the anvil has a direction of curvature when in the deployed state, and the anvil is configured such that during actuation from the deployed to the collapsed state at least two adjacent segments pivot relative to each other in an inward or outward direction relative to the direction of curvature.

3. (canceled)

4. An anvil as claimed in claim 2, wherein the anvil is configured such that during actuation from the deployed to the collapsed state all adjacent segments pivot relative to each other in an outward direction relative to the direction of curvature.

5. An anvil as claimed in claim 1, wherein the segments have a length direction and the length direction is orientated substantially parallel or substantially perpendicular to the first direction in the collapsed state.

6. (canceled)

7. An anvil as claimed in claim 1, wherein in the deployed state the anvil is a ring-shape, a disc-shape or a dome-shape.

8. An anvil as claimed in claim 1, wherein when in the deployed state the anvil comprises a stapling surface that faces toward the proximal end, wherein the stapling surface is a surface that contacts tissue to be stapled and provides resistance to staples piercing through the tissue during a stapling operation, wherein the stapling surface comprises a plurality of recesses shaped and positioned on the surface so as to assist with the folding of the staples piercing through the tissue.

9. An anvil as claimed in claim 1, wherein when in the deployed state the anvil comprises a cutting surface that faces toward the proximal end, wherein the cutting surface is a surface that contacts tissue to be stapled and provides resistance to a cutting member that cuts through the tissue during a stapling operation, wherein the cutting surface comprises a resilient material.

10. An anvil as claimed in claim 1, wherein the anvil comprises a peripheral protective portion arranged to protect body tissue local to the anvil from being caught in the anvil.

11. An anvil as claimed in claim 1, wherein the anvil is configured to be connectable to and detachable from a surgical stapler.

12.-22. (canceled)

23. A surgical stapler comprising: a proximal end and a distal end, wherein the proximal end is proximate to the user in use and the distal end is distal from the user in use; an anvil as claimed in claim 1 at the distal end; and an actuator mechanism configured to actuate the anvil between the deployed and collapsed states, wherein the actuator mechanism is configured to be controlled from a location on the surgical stapler towards the proximal end.

24. A surgical stapler as claimed in claim 23, wherein the stapler comprises a shaft extending in the first direction, and wherein the anvil is attached to the shaft.

25. A surgical stapler as claimed in claim 23, wherein the actuator mechanism comprises a tensioning system configured to apply tension to the anvil.

26. A surgical stapler as claimed in claim 23, further comprising a head portion, the head portion being configured such that staples can be fired from it toward the anvil in the deployed state sequentially.

27. A surgical stapler as claimed in claim 23, further comprising a head portion, the head portion comprising a sharp edge for cutting the tissue.

28. A surgical stapler as claimed in claim 27, wherein the sharp edge is sloped with respect to the first direction, or wherein the sharp edge is not sloped.

29. A surgical stapler as claimed in claim 23, wherein the stapler comprises a head portion, wherein the stapler is configured such that when the stapler is actuated the following occur sequentially: the anvil is deployed; the anvil and the head portion are drawn together; and when the anvil is proximate to the head portion the staples are fired.

30. A method comprising actuating the anvil of claim 1 between the collapsed state and the deployed state.

31. A method of stapling body tissue using an anvil as claimed in claim 1 and a stapler head, wherein when the anvil is positioned on one side of a piece of tissue to be stapled and the stapler head is on the other side of the piece of tissue to be stapled the following steps are performed sequentially: drawing the anvil and the stapler head together; and when the anvil is proximate to the stapler head, firing staples from the stapler head through the tissue such that the anvil offers resistance to fold the staples.

32. A method as claimed in claim 31, wherein the staples are fired sequentially.

33. (canceled)

34. A surgical stapler as claimed in claim 27, wherein in the deployed state the anvil is a ring-shape, and wherein the head portion, the sharp edge and the anvil are shaped such that a radially innermost surface of the anvil cooperates with the sharp edge to cut body tissue proximate the radially innermost surface of the anvil

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0204] Certain preferred embodiments will now be described by way of example only and with reference to the accompanying drawings, in which

[0205] FIG. 1 shows a prior art stapler and anvil in use;

[0206] FIGS. 2(a)-2(f) show an overview of a method of stapling tissue;

[0207] FIG. 3 shows the result of the method of FIG. 2;

[0208] FIGS. 4(a)-4(c) show a first embodiment of an anvil;

[0209] FIGS. 5(a)-5(b) show a second embodiment of an anvil;

[0210] FIG. 6 shows the second embodiment in use;

[0211] FIGS. 7(a)-2(c) show a third embodiment of the an anvil;

[0212] FIGS. 8(a)-8(b) show a fourth embodiment of an anvil;

[0213] FIG. 9 shows a fifth embodiment of an anvil;

[0214] FIGS. 10(a)-10(d) show a sixth embodiment of an anvil;

[0215] FIGS. 11(a)-11(c) show enlarged views of the anvil of the sixth embodiment;

[0216] FIG. 12 shows a seventh embodiment of an anvil;

[0217] FIGS. 13(a)-13(e) show an eighth embodiment of an anvil;

[0218] FIG. 14 shows a ninth embodiment of an anvil;

[0219] FIGS. 15(a)-15(c) show a tenth embodiment of an anvil as part of an anvil assembly;

[0220] FIG. 16 shows an eleventh embodiment of an anvil as part of an anvil assembly; and

[0221] FIGS. 17(a)-17(d) show a twelfth embodiment of an anvil.

DETAILED DESCRIPTION

[0222] With regard to FIG. 1, the prior art stapler 1 and anvil 20 are used to connect two tubes of the body together. These tubes may be for instance two portions of the gastrointestinal tract (such as the oesophagus, stomach, duodenum, jejunum, ileum, colon and/or rectum. The two portions may have become separated when some intermediate portions of the tissue has been removed, for example when cancerous tissue is removed.

[0223] In the prior art, the stapler 1 is inserted into tube 10 from a proximal end 12. The anvil 20 is inserted into the tube 11 from the distal end 13. Thus, to staple the two tubes 10, 11 together, access is required from two sides 12, 13. The ends 14, 15 of the two tubes 10, 11 are typically sealed, for example by staples or stitches. This sealing has occurred prior to the present stapling method, for example during removal of intermediate portions of the tissue.

[0224] During stapling, the anvil 20 and the stapler 1 are pressed toward each other. This draws the ends 14, 15 of the two tubes 10, 11 towards each other. When the anvil 20 presses against stapler 1, and the tissue of the ends 14, 15 of the tubes 10, 11 are effectively clamped between the stapler 1 and the anvil 20, the stapler 1 can fire staples toward the anvil 20 and hence through said tissue. The anvil 20 provides resistance to said staples and hence aids in their folding. Once folded, the staples hold the two tubes 10, 11 together. The stapler 1 and anvil 20 are circular and produce a double concentric ring of staples.

[0225] The stapler 1 comprises a circular knife edge (not shown) that is then pressed against the anvil 20 inside the ring of staples. This cuts through the ends 14, 15 of the tubes 10, 11, thus forming a path between the tubes 10, 11. The stapler 1 is then removed from the proximal end 12 and the anvil is removed from the distal end 13.

[0226] With regard to FIG. 2, a proposed method is shown. Like the prior art method of FIG. 1, this method is for joining two tubes 110, 111 together. However, unlike the prior art, access is only required from the proximal end 112: access is not required from the distal end 113.

[0227] In FIG. 2a, a stapler 101 is introduced into the first tube 110 from the proximal end. The stapler 101 comprises a collapsible anvil 120. In FIG. 2a, the anvil 120 is in its collapsed state. In FIG. 2b, the anvil 120 is passed through the closed end 114 of the first tube 110. This is achieved by cutting through the closed end 114 with a cutting element 121 attached to the distal end of the anvil 120 when in the collapsed state. The cutting element 121 is a cutting tip 121 that can be removed manually from the anvil 120 once a hole is formed in the closed end 114, or may be made of material such that it dissolves in the body after the hole is formed. A small hole 116 is formed in the closed end 115 of the second tube 111. The small hole 116 is formed by another means (i.e. not by the stapler 101). In FIG. 2c, the anvil 120 is passed through the small hole 116. In FIG. 2d, the anvil 120 is actuated to its deployed state. More details on how this is achieved are provided below. In the deployed state, the area covered by the anvil 120 is significantly larger than the in the collapsed state.

[0228] In FIG. 2e, the anvil 120 is drawn toward the stapler head 102 such that the ends 114, 115 of the tubes 110, 111 are held between the anvil 120 and the stapler head 102. Once this occurs, staples are fired sequentially from the stapler head 102 through the two layers of tissue and are folded over by the resistance offered by the anvil 120. This joins the two tubes 110, 111 together by a double ring of staples 118. Once this occurs, a sharp edge (not shown) of the stapler head 102 cooperates with the inside of edge of a ring of the anvil 120 to cut out a portion of the ends 114, 115, thus leaving an opening 117 between the first and second tubes 110, 111. In FIG. 2f, the anvil 120 is actuated to its collapsed state and the stapler 101 can then be removed from the proximal end 112.

[0229] With regard to FIG. 3, this shows the result of the method of FIG. 2 once the stapler 101 has been withdrawn. As can be seen, the two tubes 110, 111 are held together with a ring of staples 118 (which is preferably a double ring, though not shown). The staples 118 are folded over on the distal side of end 115, though this cannot be seen from FIG. 3. The hole 117 provides a passage through ends 114, 115 between the two tubes 110, 111.

[0230] With regard to FIG. 4, a first embodiment of the anvil 220 is shown. The anvil 220 is configured to be actuated between a deployed state (FIGS. 4b and 4c) and a collapsed state (FIG. 4a). The anvil 220 comprises a plurality of segments 230 arranged end-to-end. The anvil 220 is elongated in the collapsed state, the anvil 220 being elongated generally in a first direction (D.sub.1). The area covered by the anvil 220 is greater in the deployed state (A.sub.D) than the collapsed state (A.sub.c) when viewed along the first direction. The anvil 220 is configured such that the segments 230 rotate about a rotation axis along a second direction (D.sub.2) perpendicular to the first direction (D.sub.1) when the anvil 220 is actuated between the deployed and the collapsed states. The anvil 220 is configured such that adjacent segments 230 pivot relative to each other about a pivot axis along a third direction (D.sub.3) perpendicular to the second direction (D.sub.2) when the anvil 220 is actuated between the deployed and collapsed states. In FIG. 4a, when the anvil 220 is collapsed, the third direction (D.sub.3) is perpendicular to the first direction (D.sub.1). However, as the segments 230 rotate about the second direction (D.sub.2) to the deployed state, the third direction (D.sub.3) also rotates. In the deployed state, the third direction (D.sub.3) is parallel to the first direction (D.sub.1), as can be seen in FIGS. 4b and 4c.

[0231] The anvil 220 is actuated by an actuator mechanism (not shown) of the stapler. The actuator mechanism comprises an actuator line (not visible in FIG. 4, but visible in FIG. 5) that passes through the segments 230. When tension is applied to the anvil 220 via the actuator line, the anvil 220 is actuated from the collapsed state to the deployed state. When tension is not applied (or released), the anvil 220 collapses into the collapsed state.

[0232] In the collapsed state, all adjacent segments 230 are physically attached or fixed to each other. This physical attachment may be via a hinge or pivot point, and/or at least via said actuator line.

[0233] In the deployed state, as can be seen in FIG. 4b, all but one pair of adjacent segments 230 of the anvil are physically attached or fixed to each other. There are two adjacent segments 231, 232 that are not physically attached to each other.

[0234] The actuator line is fixed to the distal-most segment 231. The actuator line is free to move relative to each of the segments 230 it passes through. However, when tension is applied, the actuator line cooperates with the distal-most segment 231 such that the tension in the actuator line pulls the distal-most segment 231 toward the other segments 230, thus acting to compress the segments 230. The segments 230 are shaped such that when this tensioning occurs, the anvil 220 changes from its collapsed to its deployed state.

[0235] During actuation, each segment 230 rotates and pivots. All of the segments 230 of the anvil rotate the same amount, which is about 90.

[0236] Each segment 230 has a length (L), which is generally oriented in the elongated direction of the anvil in the collapsed state (D.sub.1), and is orientated generally perpendicular to the first direction (D.sub.1) when in the deployed state. Each segment 230 is generally elongated (even if it is curved) and the length (L) is generally in the direction of said elongation.

[0237] Each segment 230 has a width (W). The width (W) is perpendicular to the length (L). The width (W) of each segment 230 defines the surface for providing resistance to the staples during the stapling operation. The width (W) should therefore be sufficiently large to provide a large enough area to provide resistance to the staples during the stapling operation.

[0238] Each segment 230 has a depth (d). The depth (d) is generally perpendicular to the length (L) and the width (W). The depth (d) should be sufficient for providing adequate strength and rigidity to the anvil 220 for providing resistance during the stapling operation. The depth (d) direction may be orientated generally in the first direction when the anvil is deployed.

[0239] Each segment 230 may comprise two ends 233, 234, one at each end of the length (L) of the segment, and extending across the width (W) and depth (d) of each segment 230. These ends 233, 234 comprise respective end surfaces.

[0240] The segments 230 are shaped such that when the anvil 220 is in its deployed state, the segments form a rigid anvil 220. The segments may be shaped such that when the anvil 220 is in its deployed state, the end surfaces 233, 234 of the adjacent segments 230 abut each other. This abutment is such that there is greater end surface 233, 234 contact between adjacent segments 230 when the anvil 220 is deployed than when the anvil 220 is collapsed. Further, as mentioned above, there is a compression force present that forces the segments 230 in a way that increases the contact and/or friction between the end surfaces 233, 234 of adjacent segments 230, but does not cause any movement of the segments 230 due to their shapethe segments 230 are shaped to provide a reaction force. Thus, the segments 230 are stressed when in the deployed state, and are held against movement (despite the force being present) by the shape of each segment 230 causing an interaction between the end surfaces 233, 234 of neighbouring segments 230, which provides the reaction force and hence maintains the stressed state.

[0241] As shown in FIG. 4, each of the segments 230 is curved. These curves are arc-shapes. The arc-shape is an arc of a circle. The segments 230 are curved such that they collectively form a substantially continuous circle shape when the anvil is deployed (as can be seen in FIG. 4b).

[0242] Both the outermost periphery of the segments 230 when in the deployed state and the innermost periphery of the segments 230 when in the deployed state define circular shapes, which are concentric.

[0243] The ends of the segments 233, 234 are perpendicular to the direction of the curve (e.g. the tangent of the circle) of the segment 230 at the respective ends 233, 234 of the segment 230. The ends 233, 234 extend in the radial direction of the circle, when deployed. Adjacent segments 230 pivot relative to each other about a pivot point 235. The pivot point 235 is located where the end of one segment 233, 234 meets the end of an adjacent segment 230, when the anvil 220 is in the collapsed state.

[0244] In the deployed state, the anvil 230 is a ring-shape. The ring is substantially continuous. By substantially continuous, it is meant that the ring is at least largely complete, but there is a minor break minor break in the ring. For example, a distal end of the end segment 231 of the anvil is not physically attached to its adjacent segment 232 when in the deployed ring shape. However, it may be pressed against said adjacent segment 232 by compression forces. The ring is a circular shape.

[0245] All of the segments 230 of the anvil 220 are orientated such that they extend (e.g. the direction from one end 233 of a segment to the other end 234 of the same segment, i.e. the length direction (L)) substantially perpendicular to the first direction (D.sub.1) when the anvil 234 is deployed.

[0246] When the anvil 220 is deployed, the segments 230 of the anvil 220 define a plane. The normal of this plane is substantially parallel with the first direction (D.sub.1).

[0247] The area covered by the anvil (A.sub.D) is the area defined by the outer periphery of the anvil ring 220 when in the deployed state. Of course, the actual area provided by the anvil for providing resistance to staples may be smaller than the area covered by the anvil, since not all of the area covered by anvil may provide resistance to staples since there may be gaps (e.g. the area of an annulus is smaller than the area of a circle). The actual area provided by the anvil is determined by the circumference of the wring and the width (W) of the segments 230.

[0248] The rotation of the segments 230 about a rotation axis in the second direction (D.sub.2) may be thought of as a re-orientation of the segments 230 between the collapsed and deployed states. The rotation is of the general length-direction (L) of the segments 230. For instance, in the collapsed state, the length-direction (L) of the segments is generally in the first direction (D.sub.1). However, during deployment this length-direction (L) rotates about an axis in the second direction (D.sub.2). Thus, in the deployed state, the length-direction (D.sub.2) of the segments is not in the first direction (D.sub.1). Rather, the length-direction (L) is 90 to the first direction (D.sub.1).

[0249] Each of the segments 230 rotates by substantially the same amount between the collapsed and the deployed states.

[0250] The pivoting of the segments 230 about a pivot axis in the third direction (D.sub.3) may be thought of as a re-orientation of the segments 230 between the collapsed and deployed states. The pivoting may be of the general length-direction (L) of the segments. For instance, in the collapsed state, the length-directions of the segments (L) are generally in the first direction (D.sub.1), and hence generally parallel and colinear with each other. However, during deployment this length-direction (L) rotates about an axis in the third direction (D.sub.3). Thus, in the deployed state, the length-directions (L) of respective segments 230 are not parallel with each other. Rather, they pivot and are non-parallel with each other.

[0251] In the collapsed state, the length-directions (L) of respective segments are substantially 0 to each other. However, in the deployed state, the length-directions (L) of the adjacent segments are around 60 to each other.

[0252] Each of the segments 230 pivot relative to their adjacent segments by substantially the same amount between the collapsed and the deployed states.

[0253] When in the deployed state, the anvil 220 has a direction of curvature (C). The direction of curvature (C) is towards the centre of the circle defined by the ring anvil 220. In FIG. 4, all adjacent segments 230 pivot relative to each other in an outward direction relative to the direction of curvature (C) when the anvil 220 changes from the deployed state to the collapsed state. Such pivoting effectively straightens the ring. Correspondingly, all adjacent segments 230 pivot relative to each other in an inward direction relative to the direction of curvature (C) when the anvil changes from the collapsed state to the deployed state. Such pivoting effectively closes the ring.

[0254] Whilst the location of the axis of the pivot is different for each adjacent pair of segments (the axis of the pivot will be located at the pivot point 235 located where two adjacent segments 230 meet), every pivot axis is in the same direction as each other (the third direction (D.sub.3)).

[0255] At or toward the proximal end of the stapler, the stapler may comprise a user interface, such as a handle. The user interface may be connected to the actuator and may allow the user to control the actuator mechanism.

[0256] The anvil 220 may be connected to the remainder of the stapler 101, such as the stapler head 102, via a shaft 250. The shaft 250 is elongated. The shaft 250 is located at the distal end of the stapler 101, or may be attached to the distal end of the stapler 101. The actuator mechanism (such as the actuator line) passes through the shaft 250. The shaft 250 extends generally in the first direction (D.sub.1). The shaft 250 is typically located a central longitudinal axis of the stapler 101 or stapler head 102. The shaft 250 is substantially rigid and inflexible, i.e. it does not rotate or pivot like or with the anvil segments 230; rather, it may remain stationary relative to the remainder of the stapler 101 during actuation of the anvil 220.

[0257] The anvil 220 is attached to the distal end of the shaft 250. Together, the shaft 250 and the anvil 220 may form an integral anvil assembly that is attachable to or detachable from the remainder of the stapler 101. The anvil 220 is attached to the shaft 250 by a supporting arm 260. The supporting arm 260 is arranged such that the shaft 250 is within the area covered by the ring (A.sub.D) when viewed along the first direction (D.sub.1) when the ring is deployed. The shaft 250 is toward the centre (but not at the exact centre) of the ring.

[0258] In the deployed state, the supporting arm 260 extends partially in the plane defined by the anvil ring 220. In the collapsed state, the supporting arm extends in the first direction (D.sub.1) colinearly with the collapsed anvil 220.

[0259] The supporting arm 260 comprises segments 261, similar to those of the anvil 220. The segments 261 of the supporting arm 260 are shaped such than when the anvil is actuated, the supporting arm 260 is also actuated by the actuator mechanism such that the supporting arm 260 acts to position the anvil 220 in the correct position and orientation.

[0260] The anvil 220 is attached to the shaft 250 by only one supporting arm 260.

[0261] In the collapsed state, the shaft 250, the support arm 260 and the anvil 220 may all extend substantially in the first direction (D.sub.1), co-linearly in an end-to-end fashion. However, in the deployed state, the support arm 260 may act as a spoke between the deployed anvil 220 and the shaft 250.

[0262] With regard to FIG. 5, a second embodiment of an anvil 320 is shown. Except where discussed below, this embodiment is substantially identical to that of FIG. 4. FIG. 5a shows the anvil 320 in the collapsed state, and FIG. 5b shows the anvil 320 in the deployed state.

[0263] The pivots 335 between adjacent segments 330 are hinges. Every segment 330 in the deployed state is physically attached to both of its adjacent segments 330.

[0264] The anvil 320 is attached to the shaft 350 by a plurality of supporting arms 360, 361. In this case there are two supporting arms 360, 361. The supporting arms 360, 361 support opposite sides of the anvil ring when the anvil 320 is deployed. The two supporting arms 360, 361 are spaced around the ring by around 180 from each other. The supporting arms 360, 361 are rotationally symmetrically arranged around the ring.

[0265] Each supporting arm 360, 361 is the same length. Thus, the shaft 350 is at the centre of the ring.

[0266] Each supporting arm 360, 361 extends between the shaft 350 and a respective segment of the ring 331, 332. The supporting arms 360, 361 attach to the respective segments 331, 332 at a point on the segment 331, 332 that is distant from either end 333, 334 of said segment 331, 332. In this case, the point is at the midpoint along the length-direction (L) of the segment 331, 332. In addition to the pivots 335 between adjacent segments 330, a pivot 336 is provided to connect the supporting arm 360, 361 to the segment 331, 332, to allow the segment 331, 332 to pivot relative to the supporting arm 360, 361 during actuation of the anvil.

[0267] Each supporting arm 360, 361 has the same length.

[0268] Each supporting arm 360, 361 pivots relative to the segments 331, 332 of the anvil about axes that are orientated in the third direction (D.sub.3).

[0269] In the collapsed state, the shaft 350, the support arms 360, 361 and the anvil 320 may all extend substantially in the first direction (D.sub.1), however the anvil 320 and the supporting arms 360, 361 are parallel to, but radially offset from, the shaft 350. The radial offset is as small as possible, such as the supporting arms 360, 361 and the anvil 320 are touching the shaft 350. Thus, the anvil 320 and supporting arms 360, 361 are gathered alongside the shaft 350 (i.e. they may overlap with the shaft 350 in the first direction (D.sub.1)).

[0270] Adjacent segments 337, 338; 337, 331; 339, 340; 340, 332 pivot relative to each other in an outward direction relative to the direction of curvature of the anvil 320 when the anvil changes from the deployed state to the collapsed state. Thus, these adjacent segments 337, 338; 337, 331; 339, 340; 340, 332 pivot relative to each other in an inward direction relative to the direction of curvature when the anvil 320 changes from the collapsed state to the deployed state. In this case, since there are six segments, these adjacent segments 337, 338; 337, 331; 339, 340; 340, 332 pivot relative to each other by 60.

[0271] In addition to this, adjacent segments 331, 339; 332, 338 pivot relative to each other in an inward direction relative to the direction of curvature when the anvil 320 changes from the deployed state to the collapsed state. Thus, these adjacent segments 331, 339; 332, 338 pivot relative to each other in an outward direction relative to the direction of curvature when the anvil 320 changes from the collapsed state to the deployed state. In this case, since there are six segments, these adjacent segments 331, 339; 332, 338 pivot relative to each other by 120.

[0272] There are only two pairs of adjacent segments 331, 339; 332, 338 that pivot inwardly during collapse in this manner. The remaining segments may pivot outwardly during collapse.

[0273] When the ring collapses in such a manner, the anvil may collapse into two collapsed ring halves 341, 342, as discussed below.

[0274] In the collapsed state, a first portion 343 of the anvil and the supporting arms overlaps with the shaft 350 in the first direction (D.sub.1), and a second portion 344 of the anvil 320 and the supporting arms extends beyond the distal end of the shaft 350 in the first direction (D.sub.1). The first portion 343 may be called an overlapping portion 343 and the second portion 344 may be an extending portion 344. The anvil 320 and the supporting arms 360, 361 consist of the first and second portions. The first and second portions 343, 344 are generally symmetric halves of the anvil 320 and supporting arms 360, 361.

[0275] In the deployed state, the supporting arms 360, 361 may each connect to the distal end of the shaft 350. In the collapsed state, the supporting arms 360, 361 also each connect to the distal end of the shaft 350 (e.g. at the same location as in the deployed state).

[0276] This connection location may comprise a pivot 351. The axis of this pivot 351 is in the second direction (D.sub.2). The anvil 320 and supporting arms 360, 361 can therefore rotate about this pivot 351 so as to rotate the segments 330 of the anvil 320 around the axis in the second direction (D.sub.2). The pivot 351 is located at the distal end of the shaft 350.

[0277] In the deployed state, the anvil 320 forms a ring and the supporting arms 360, 361 form spokes connecting the ring to the shaft 350.

[0278] In order to move from the deployed state to the collapsed state, the ring may collapse. This may occur by allowing two pairs of adjacent segments 332, 338; 331, 339 to pivot inwardly with respect to each other (as is described above) and allowing the remaining pairs of adjacent segments 337, 338; 337, 331; 339, 340; 340, 332 to pivot outwardly with respect to each other. The opposite pivoting occurs in the deploying stage (e.g. from collapsed state to deployed state).

[0279] The two pairs whose segments pivot inwardly with respect to each other 332, 338; 331, 339 are substantially 180 opposite each other on the ring. The anvil 320 has an even number of segments 330.

[0280] Such a collapsed ring means that half of the segments 338, 337, 331 of the anvil form a first collapsed half 341 and the remaining segments 332, 340, 339 of the anvil form a second collapsed half 342 of the ring. These two collapsed halves 341, 342 may overlap in the first direction (D.sub.1) in the collapsed state. One of the pivots 335 about which adjacent segments 332, 338; 331, 339 pivot inwards during collapse may be located at the distal end of the collapsed anvil (which is elongated in the first direction (D.sub.1)) and the other of the pivots 335 about which adjacent segments 332, 338; 331, 339 pivot inwards during collapse may be located at the proximal end of the collapsed anvil.

[0281] The two supporting arms 360, 361 take the form of a single bar 362 whose midpoint is connected to the distal end of the shaft 350, i.e. at the pivot 351. This single bar 362 thus comprises both supporting arms 360, 361. The bar 362 is also connected to opposite segment 331, 332 by the pivots 336.

[0282] In the deployed state, the bar 362 extends in the plane of the ring in the radial direction. In the collapsed state, the bar 362 extends substantially parallel to the length-direction collapsed ring segments (L), i.e. substantially parallel to the first direction (D.sub.1). In the collapsed state, the bar 362 is located in between the two collapsed half rings 341, 342.

[0283] The bar 362 is straight.

[0284] Although not shown, to actuate the pivoting of each supporting arm relative to the segments, an actuator line may connect between the supporting arm and the segments. The actuator line may be arranged such that when it is tensioned (e.g. by action from the user at the proximal end of the stapler), the supporting arm may pivot relative to the segments. This in turn may cause the adjacent segments to pivot relative to each other. This (possibly in combination with a suitable biasing) may drive the anvil between the deployed and collapsed states.

[0285] Both when deployed and collapsed, the anvil 320 is only connected to the distal end of the shaft 350. FIG. 5a shows the anvil 320 and the shaft 350 as an anvil assembly that is detachable from the remainder of the stapler 102.

[0286] Although not shown in FIG. 5, there may be a cutting element 121 present (shown in FIG. 2). The cutting element 121 may be in the form of a tip fitted onto the distal end of the anvil 320, when the anvil 320 is in its collapsed state (e.g. proximate to pivot 335). The tip 121 may be shaped such that it is sufficiently sharp to cut through the tissue, i.e. the tip 121 may be sharp and/or pointed. Alternatively, the anvil 320 may be placed inside a tube (see FIG. 14) to cut the tissue, or indeed the distal end of the anvil 320 when in the deployed state (e.g. proximate to pivot 335) may be shaped to form a cutting element.

[0287] With regard to FIG. 6, this shows the anvil of FIG. 5 in use inside a tube 111 of the body. As can be seen, the ring shape is sized and shaped so as to best fit into the tube without overly stretching the tube 111.

[0288] With regard to FIG. 7, a third embodiment of an anvil 420 is shown which is very similar to the second embodiment of the anvil 320. FIG. 7a shows the anvil 420 in the collapsed state, and FIGS. 7b and 7c show the anvil 420 in the deployed state.

[0289] In contrast to FIG. 5, the actuator line 470 for actuating the anvil 420 is explicitly shown. The actuator line 470 connects between the supporting arm and the anvil. A first actuator line 470 extends between the first supporting arm 460 and the segment 431 to which said supporting arm is attached. A second actuator line 470 extends between the second supporting arm 461 and the segment 470 to which said supporting arm 461 is attached. The actuator line 470 extends between the supporting arm and the anvil at an angle () relative to the supporting arm. This means that when the actuator line 470 is tensioned, the supporting arm is pivoted relative to the anvil, and hence the anvil 420 can collapse.

[0290] The surface of the anvil 420 that faces the proximal end 112 when deployed may be thought of as the stapling surface 491. The stapling surface 491 is the surface that contacts the tissue and provides resistance to the staples piercing through the tissue during the stapling operation. The stapling surface 491 is generally annular.

[0291] The stapling surface 491 comprises a plurality of recesses 490. The recesses 490 are shaped and positioned so as to interact with the staples piercing through the tissue so as to assist with the folding of the staples. There may be one recess 491 per stapler head hole 104, and each recess 491 may be located to interact with a staple coming from a respective hole 104. In the specific embodiment of FIG. 7, the recesses 490 are arranged in a ring, corresponding to the ring shape of the deployed anvil 420. The recesses 490 are arranged in two concentric rings, corresponding to the two concentric rings of the openings 104 of the stapler head 102. Although only shown in FIG. 7, these recesses 490 may be present in all embodiments.

[0292] With regard to FIG. 8, this shows a fourth embodiment of an anvil 520 which is very similar to that of the second and third embodiments. FIG. 8a shows the anvil 520 in the deployed state, and FIG. 8b shows the anvil 320 in the collapsed state.

[0293] In this embodiment each supporting arm 560, 561 extend between the shaft 550 and the location 535 between adjacent segments 530 of the ring. This allows for the possibility of using the same pivot point 535 for allowing the anvil 520 to pivot relative to the supporting arm 560, 561 as is used for allowing adjacent segments 530 to pivot relative to each other. However, it does mean that the length of the supporting arm 560, 561 may need to be longer in the collapsed state than in the deployed state (or vice versa). Thus, a curved and flexible supporting arm 560, 561 can be used. Such a supporting arm 560, 561 may be inflexible/rigid in the third direction (D.sub.3) but may be flexible perpendicular to the third direction (D.sub.3).

[0294] With regard to FIG. 9, this shows a fifth embodiment of an anvil 620 which is very similar to that of the second and third embodiments. However, in this embodiment, there are four supporting arms 660, 661, 662, 663. These take the form of two bars 664, 665 whose approximate midpoints are connected to the distal end of the shaft, e.g. at the pivot 351. The bar 664 comprises the two supporting arms 660, 661 and the bar 665 comprises the two supporting arms 662, 663. Each bar 664, 665 connects to two different opposite segments: bar 664 connects between segments 631 and 632 and bar 665 connects between segments 639 and 638. Each bar is connected to the respective segments in the same way as the bar of FIG. 5.

[0295] Each bar 664, 665 comprises a kink 666, 667. The kink 666, 667 is present at the location where the bar is connected to the shaft. Two straight portions 660, 661; 662, 663 of equal length join at the kink 666, 667.

[0296] When deployed, the bars 664, 665 are spaced by an angle, such as around 60. During collapse, this angle is reduced to close to 0 such as less than 10. The bars 664, 665 thus pivot relative to each other during collapse. This pivot is about an axis in the third direction.

[0297] The anvil 620 also comprises an outer protective ring 692. The outer ring 692 is located on the outer edge of the anvil ring. The outer ring 692 is flexible and/or elastic, and may be made from rubber. The outer ring 692 is for protecting the tissue from being caught in the moving parts of the anvil 620, which may otherwise occur during deployment or collapse of the anvil 692, or at another time.

[0298] With regard to FIG. 10, this shows a sixth embodiment of an anvil 720 which is similar to that of the preceding embodiments, except where discussed below.

[0299] In the collapsed state, all of the anvil 720 may overlap with the shaft in the first direction (D.sub.1). This is shown in FIG. 10b.

[0300] In the deployed state, the supporting arms 760, 761, 762 all connect to the distal end of the shaft 750. In the collapsed state, the supporting arms 760, 761, 762 also all connect to the shaft 750, but may connect to different locations on the shaft 750.

[0301] At least two and preferably all of the supporting arms 760, 761, 762 are able to rotate about the shaft 750 (e.g. about an axis in the first direction (D.sub.1)). During actuation of the anvil 720 the at least two, and preferably each, of the supporting arms 760, 761, 762 rotate about the shaft 750 (e.g. about an axis in the first direction (D.sub.1)).

[0302] All of the supporting arms 760, 761, 762 are able to pivot relative to the shaft 750 (e.g. about an axis perpendicular to the first direction and perpendicular to the direction in which the respective supporting arm extends). During actuation of the anvil 720, each of the supporting arms 760, 761, 762 pivot relative to the shaft 750 (e.g. about an axis perpendicular to the first direction and perpendicular to the direction in which the respective supporting arm extends).

[0303] Two of the supporting arms 761, 762 are slidable relative to the shaft 750 in the first direction (D.sub.1). During actuation of the anvil 720, the two supporting arms 761, 762 slide relative to the shaft 750 (e.g. about an axis in the first direction (D.sub.1)).

[0304] Each of the supporting arms 760, 761, 762 is able to pivot relative to the anvil 720.

[0305] Each supporting arm 760, 761, 762 connects between a respective location on the anvil 720 and a respective location on the shaft 750. Each supporting arm 760, 761, 762 are connected to a different location on the anvil 720 (such as different segments 730). In the collapsed state, each supporting arm 760, 761, 762 connect to the shaft 750 at different positions in the first direction (D.sub.1). In the deployed state, each supporting arm 760, 761, 762 connects to the shaft at substantially the same position in the first direction (D.sub.1), e.g. at the distal end of the shaft 750.

[0306] In the deployed state, the anvil 720 forms a ring and the supporting arms 760, 761, 762 form spokes connecting the ring to the shaft 750.

[0307] In order to move from the deployed state to the collapsed state, the ring may collapse. This may occur by having only one pair of adjacent segments 731, 732 in the ring that is not physically attached/fixed to one another (though they are in contact with each other in the ring). The supporting arms 760, 761 are actuated by the actuator mechanism to rotate and pivot them relative to the shaft 750 and to slide them relative to the shaft 750.

[0308] An actuator line 770 connects each of the supporting arms 760, 761, 762. When tension is applied to the actuator line 770, the supporting arms 760, 761, 762 are drawn together thus causing the actuation toward the deployed state (i.e. from FIGS. 10a, to 10b, to 10c).

[0309] When the supporting arms 760, 761, 762 are actuated in the reverse direction (e.g. by releasing the tension and using natural resilience of the anvil 720), their motion may cause the ring to collapse. The ring may collapse such that is opens out into a generally straight line (see FIGS. 10c and 10b). This may occur by having each pair of physically attached adjacent segments 730 pivot outwardly with respect to the curvature of the ring.

[0310] As the segments 730 pivot outwardly with respect to the curvature of the ring, the anvil 720 changes from a ring shape towards a straight-line shape. The general orientation of the anvil 720 also changes as this occurs, as can be seen in FIG. 10c. The orientation changes from being perpendicular to the first direction (D.sub.1) when in the deployed state to the first direction (D.sub.1) in the collapsed state. This orientation change necessarily/automatically occurs due to the manner in which the supporting arms 760, 761, 762 connect to the anvil 720 and the shaft 750, and since the supporting arms 760, 761, 762 have fixed lengths.

[0311] The opposite motion occurs in the deploying stage (e.g. from collapsed state to deployed state).

[0312] As can be seen in FIG. 10b, an anvil ring that collapses in this way, in its collapsed state, takes the form of a straight line of segments 730. This line of segments 730 overlaps the shaft 750 in the first direction (D.sub.1). The line of segments 730 is adjacent to the shaft. Indeed, as can be seen from the plan view of FIGS. 11b and 11c, the segments 730 may comprise cutaway portions 735 so that they can more closely fit to the shaft 750 and so that the area (A.sub.C) of the collapsed anvil 720 is reduced.

[0313] In the collapsed state, one of the supporting arms 760 is connected to the shaft 750 at a location at the distal end of the shaft 750. This supporting arm 760 is not slidable relative to the shaft. The remaining supporting arms 761, 762 are connected to the shaft at locations distant from the distal end of the shaft 750.

[0314] In the collapsed state, each of the supporting arms 760, 761, 762 extend substantially in the first direction (D.sub.1) toward the proximal end adjacent to the shaft 750. The supporting arms 760, 761, 762 are between the anvil 720 and the shaft 750.

[0315] FIG. 10a shows a casing 780 in which the shaft 750, the anvil 720 and the supporting arms 760, 761, 762 can be held, for example during insertion through the small hole 116 in the tissue. The casing 780 is cylindrical and is part of the stapler 101.

[0316] FIG. 11 shows an enlarged view of the anvil 720 of FIG. 10.

[0317] With regard to FIG. 12, this shows a seventh embodiment of an anvil 820. This is similar to the sixth embodiment. However, in the deployed state, the anvil 820 is dome-shape. The dome is substantially continuous.

[0318] The dome has a curved periphery and may be a generally solid shape (i.e. there may be no large hole in the centre, unlike the ring). The periphery is circular.

[0319] The dome has at its peak the distal end 851 of the shaft 850. This distal end 851 is flared or enlarged, in comparison to the remainder of the shaft 850. The distal end 851 meets with inner surfaces 834 of the segments 830 to form the dome. The segments 830 slope down away from the distal end 851 toward the proximal end with increasing radial distance from the shaft 850.

[0320] The segments also comprise cutaways 835 which allow the segments to fit as closely as possible to the shaft in the retracted position.

[0321] Unlike the sixth embodiment, in the collapsed state, the anvil 820 is arranged in two lines of segments 830, one line on either side of the shaft 850.

[0322] The stapler 101 of the present disclosure comprises a head portion 102 at or toward the distal end of the stapler 101. The shaft 250, 350, 450, 650, 750, 850 and/or the anvil 120, 220, 320, 420, 520, 620, 720, 820 and/or the supporting arm(s) 260, 360, 361, 460, 461, 560, 561, 660, 661, 662, 663, 760, 761, 762 are housed within the head and are extend out from the head in the distal direction, or may be extendable out from the head in the distal direction. This can be seen in FIG. 5.

[0323] The head 102 comprises a housing 103 around the shaft 350. The housing 103 takes the form of a tube that has a similar shape (in both size and shape) to the deployed shape of the anvil 320. In FIG. 5, the distal end of the tube 103 is a cylinder.

[0324] The distal end of the head 101 may comprises openings 104 for allowing staples to pass through the head 101. The holes 104 are arranged in two concentric rings.

[0325] The head 101 and the anvil 320 are arranged and shaped such that when the anvil 320 is in the deployed position, and the stapling operation is carried out, staples are pushed through the holes 104 and through the tissue 114, 115 between the head 101 and the anvil 320. When the staples meet the anvil 320, the anvil 320 provides resistance to the staples so that the staples fold and hold the tissue. This provides a ring of staples.

[0326] The ring of staples comprises a double ring of staples.

[0327] The head 101 is configured such that the staples can be fired sequentially. The inner ring of staples can be fired first and the outer ring of staples can be fired second (or vice versa).

[0328] The head 101 also comprises a sharp edge (not shown) for cutting the tissue between the head 101 and the anvil 320.

[0329] Regarding FIG. 13, this shows an eighth embodiment of an anvil 920 that is substantially identical to the second embodiment 320 except where discussed below.

[0330] In the deployed position (not shown) the anvil 920 looks substantially similar to anvil 320. However, there are some differences in its collapsed state.

[0331] There are eight segments 930 making up the anvil ring.

[0332] Instead of the bar 362, the supporting arms are made from a single plate 962. This plate does not sit in between the first collapsed ring half 941 and the second collapsed ring half 942, but instead is offset from the first and second collapsed ring halves 941, 942 in the third direction. The plate 962 is adjacent to and in contact with the segments 930 of the anvil 920.

[0333] Further, instead of having all of the segments 330 fixed together by pivots as shown in FIG. 5, in this embodiment the two collapsed ring halves 941, 942 are not permanently attached to one another by hinges 335. All segments 930 of the anvil 920 are attached to adjacent segments by hinges, except for the segments 931, 932, 938, 939 on the ends of the collapsed ring halves 941, 942. These segments instead include an arrangement such that segments 932 and 938 and segments 931 and 939 are held relative to each other when in the deployed state, but are allowed to separate when in the collapsed state. This separation occurs by a mixture of pivoting and sliding motions. Such an arrangement may be one of the segments 938, 939 comprising a tongue 993 and an adjacent segment 931, 932 comprising a groove 994 shaped to accept and cooperate with the tongue 993 when the anvil 920 is deployed.

[0334] These differences between the second embodiment and the eighth embodiment allow the segments 930 of the first and second collapsed ring halves 941 and 942 to be adjacent one another (e.g. in actual contact with each other) when in the collapsed state. This reduces the cross-section area of the anvil 920 as can be appreciated from FIG. 13c.

[0335] Regarding FIG. 14, this shows a ninth embodiment of the present invention that comprises the stapler 101 and an anvil 1020 that is substantially identical to the anvil 220 of the first embodiment shown in FIG. 4. FIG. 14 shows in more detail the cutting element 121 discussed above in relation to FIG. 2.

[0336] Thus, the stapler 101 of FIG. 14 comprises a cutting element 1021. The cutting element 1021 takes the form of a needle-like elongated tube made of plastic that extends in the first direction. The anvil 1020 is located the tube 1021 when the anvil is in the collapsed state. The tube 1021 tapers to a sharp end that is suitable for cutting tissues.

[0337] In use, as mentioned above, the stapler 101 is used to staple the closed end of the proximal tube 114 to the closed end of the distal tube 115. The cutting element 1021 cuts through the closed end of the proximal tube 114 only. This occurs when the cutting element 1021 is moved together with the collapsed anvil 1020 toward the distal direction. When the cutting element 1021 and anvil 1020 reach the tissue, the cutting element 1021 cuts through the closed end of the proximal tube 114. Continued movement in the distal direction allows the cutting element 1021 and the anvil 1020, in its collapsed configuration, to pass through the cut hole in the proximal piece of tissue 114 (see FIGS. 2a and 2b). The cutting element 1021 is then removed, as discussed above (e.g. either manually or dissolved). The collapsed anvil 1021 is then inserted through a hole 116 in the closed end of the distal tube 116, which has been created by a cutting means not part of the stapler 101. Once inserted through this hole 116, the anvil 1020 can be deployed and the stapling operation can be carried out (see FIGS. 2c to 2f).

[0338] FIG. 14 also explicitly shows the actuating line 1070 that when tensioned actuates the anvil 1020 into its deployed state.

[0339] Regarding FIG. 15, this shows a tenth embodiment of the present invention. FIG. 15 shows an anvil assembly 1119 that comprises an anvil 1120 and a first shaft 1150 and a second shaft 1152. Except where discussed below, the anvil 1120 is similar to the anvil discussed in FIG. 5. The anvil assembly 1119 is attachable to and detachable from the remainder of the stapler.

[0340] The second shaft 1152 is moveable relative to the first shaft 1150. This movement actuates the anvil 1120. This motion is a combination of a sliding motion along the first shaft 1150, a rotation about the first shaft 1150, and a pivoting away or toward the first shaft 1150.

[0341] The first shaft 1150 is attached first support arm 1151, which in turn is pivotally attached to segments of the anvil 1120.

[0342] The second shaft 1152 is attached to a second support arm 1153, which in turn is pivotally attached to segments of the anvil 1120.

[0343] The second shaft 1152 is connected to the first shaft 1150. This connection is made via a bracket 1180. The bracket 1180 allows the second shaft 1152 to slide (in the first direction) relative to the first shaft 1150, the second shaft 1152 to rotate about the first shaft 1150 when it slides, and the second shaft 1152 to pivot relative to the first shaft 1150 when it slides and rotates. These relative movements are achieved by the use of the bracket 1180. The bracket 1180 comprises a groove 1181 and the first shaft 1150 comprises a peg 1182 that slides in the groove 1181. The second shaft 1152 is housed in the bracket 1180 such that the pivoting movement mentioned above is allowed.

[0344] As can be seen in FIG. 15a, when in the collapsed state, the first and second shafts 1150, 1152 are parallel with one another and may be close to one another (preferably touching). As can be seen in FIG. 15b, to actuate the anvil 1120, the second shaft 1152 is moved relative to the first shaft 1150 such that it 1152 slides relative to the first shaft 1150 preferably in a direction toward the proximal end. Due to the groove 1181 and peg 1182 arrangement in the bracket 1180, this sliding motion also causes the second shaft 1152 to rotate relative to the first shaft 1150. Due to these two motions, the second shaft 1152 moves away from the first shaft 1150, and pivots relative to the first shaft 1150 such that the second shaft 1152 is no longer totally parallel with the first shaft 1150.

[0345] Due to the relative motion of the two shafts 1150, 1152, the first and second arms 1151, 1153 rotate relative to the two shafts 1150, 1152 and pivot relative to the segments of the anvil 1120. This causes the anvil 1120 to be actuated.

[0346] As can be seen in FIG. 15c, the completion of the relative movement of the two shafts 1150, 1152 leads to the anvil 1120 being fully deployed.

[0347] Regarding FIG. 16, this shows an eleventh embodiment of the present invention. FIG. 16 shows an anvil assembly 1219 that comprises an anvil 1220 and a shaft 1250. Except where discussed below, the anvil 1220 is substantially identical to the anvil of FIG. 5 and FIG. 7.

[0348] Similarly to the FIG. 15 embodiment, the anvil assembly 1219 is attachable to and detachable from the remainder of the stapler. However, in contrast to the FIG. 15 embodiment, a different actuation mechanism is shown. Similarly to FIG. 7, a tension-based actuation system is used. This comprises a plurality of actuator lines 1270. The anvil assembly 1219 also comprises a handle 1271 that connects to the actuator lines 1270. The handle 1271 is placed over or around the shaft 1250 of the anvil assembly 1219. The handle 1271 is attached to the proximal end of the stapler through additional lines 1272. Tension may be applied to lines 1272 by the user, which in turn may apply tension to the lines 1270 via the handle 1271. Tension in the lines 1270 may force the anvil 1220 to actuate as discussed above.

[0349] Regarding FIG. 17, this shows a twelfth embodiment of the present invention. FIG. 17 shows an anvil 1320 that is substantially identical to the anvil of FIG. 5 except where discussed below.

[0350] As shown in FIGS. 17a, 17b and 17c, when deployed, the anvil 1320 comprises a cutting surface 1395 that faces toward the proximal end. The cutting surface 1395 is a surface that contacts the tissue and provides resistance to a sharp edge 105 (which may be part of the stapler 101) that cuts through the tissue during the stapling operation. The cutting surface 1395 is made from a resilient material, such as rubber or plastic. The resilient material aids the cutting process.

[0351] The cutting surface 1395 is in the shape of an annulus. The cutting surface 1395 is radially inward of the stapling surface 1391.

[0352] The shape of the cutting surface 1395 (e.g. the radius and thickness of the annulus) is such that the sharp edge 105 (which is preferably circular and may have a flat circular cutting edge) contacts only the cutting surface 1395 during the cutting operation. This is shown in FIG. 17c.

[0353] Also as shown in FIG. 17c, the anvil 1320 comprises a recess 1396 in which the material that forms the cutting surface 1395 is housed.

[0354] The cutting surface 1395 is formed of segments 1397. There is one segment 1397 of the cutting surface 1395 for each respective segment of the anvil 1320. The segments of the anvil each comprise a recess 1398 in which respective segments 1397 of the cutting surface 1395 are housed. These recesses 1398 are toward the radially inner portion of the anvil segments.

[0355] The segments 1397 of the cutting surface 1395 are fixed to the respective anvil segments. The segments 1397 of the cutting surface 1395 are hence configured to rotate and pivot with the respective anvil segments when the anvil 1320 is deployed or retracted.

[0356] The segments 1397 of the cutting surface therefore pivot relative to one another just as the respective segments of the anvil 1320 pivot relative to one another. To allow for this pivoting, the ends of the segments of the cutting surface comprise cutaway portions 1399 that allow for the pivoting whilst forming a complete cutting surface 1395 when the anvil 1320 is deployed.

[0357] Whilst certain embodiments have been disclosed above, the skilled person would recognise that it would be possible to combine or select or isolate some of their features for use in other embodiments, as is clear from the above summary of invention section and the appended claims.

[0358] It should be apparent that the foregoing relates only to the preferred embodiments of the present application and the resultant patent. Numerous changes and modification may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.