Surgical anvil assembly for surgical stapling instrument

Abstract

A surgical anvil assembly for a circular stapling instrument includes an anvil center rod defining a longitudinal axis and an anvil head pivotally coupled to the anvil center rod and movable between a first operating state and a second inclined state. The anvil assembly further includes a locking assembly configured to selectively lock the anvil head in each of the first and second states.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Patent Application Nos. 62 / 649,278, 62 / 649,176, 62 / 649,341, 62 / 649,325, 62 / 649,304, 62 / 649,267, 62 / 649,241, 62 / 649,227, 62 / 649,217, and 62 / 649,200, all filed on March 28, 2018; the entire contents of each of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to a surgical stapling instrument, and more particularly, to a surgical anvil assembly for a circular stapling instrument having an anvil head that can be pivoted or tilted to facilitate insertion and / or removal of the anvil assembly relative to an operative site. Background Art

[0004] Circular suturing instruments for performing surgical procedures such as anastomosis, hemorrhoidectomy and mucosal resection are well known. These devices include an anvil assembly having a center rod and an anvil head supported on the center rod. Typically, in surgical procedures, the tool assembly of the circular suturing instrument is inserted into a tubular section or tissue section to connect the tissue section or remove diseased or damaged tissue from the tissue section. In order to minimize the trauma to the tissue section, the anvil head is pivotally supported on the center rod to reduce the profile of the anvil assembly during the insertion of the tool assembly and / or removal of the tool assembly from the tissue section. In some circular suturing instruments, components are broken during firing to allow the anvil head to tilt relative to the center rod. Summary of the invention

[0005] In one aspect of the present disclosure, a surgical anvil assembly for a circular stapling instrument is provided, which includes an anvil center rod, an anvil head pivotally connected to the anvil center rod and movable between a first operating state and a second inclined state, a support member slidably disposed in a groove of the anvil head and selectively engageable with the anvil center rod, and a locking assembly. The locking assembly includes an inner member supported on an outer surface of the anvil head, an outer member movably connected to the inner member, and a column interconnecting the outer member and the support member. The outer member is configured to move relative to the inner member between a first proximal position and a second distal position, in which the locking assembly maintains the support member engaged with the anvil center rod to resist movement of the anvil head relative to the anvil center rod, and in the second distal position, the locking assembly maintains the support member disengaged from the anvil center rod to allow the anvil head to move relative to the anvil center rod.

[0006] In some aspects, the locking assembly can further include a locking member protruding outwardly from the inner member. The locking member can be configured to engage the outer member when the outer member is in the second distal position to hold the outer member in the second distal position and thereby maintain the support member disengaged from the anvil center rod.

[0007] The locking member may be configured to prevent the support member from moving from the first proximal position toward the second distal position until a threshold distal force has been applied to the support member.

[0008] In some aspects, the locking member can overlap the inner lip of the outer member to resist distal movement of the outer member relative to the inner member toward the second distal position.

[0009] The locking member may include a first locking member extending radially outward from a first side of the inner member, and a second locking member extending radially outward from a second side of the inner member. The first and second locking members may engage with an inner periphery of the outer member.

[0010] In some aspects, the locking member can include a detent configured to engage an inner periphery of the outer member when the outer member is in the second distal position.

[0011] The outer member may include a lip protruding radially inward from its inner periphery. When the outer member is in the first proximal position, the lip may be disposed proximal to the pawl so that the pawl resists movement of the outer member from the first proximal position toward the second distal position. When the outer member is in the second distal position, the lip may be aligned with the pawl so that the pawl resists movement of the outer member from the second distal position toward the first proximal position.

[0012] In some aspects, the pawl can be configured to move radially inward when the outer member moves toward the second distal position. The pawl can be configured to move radially outward when the outer member moves toward the first proximal position.

[0013] The post may have a distal end disposed outside the anvil head, a mid-portion extending through the anvil head, and a proximal end disposed within a recess in the anvil head.

[0014] In some aspects, when the support member is in the first proximal position, the anvil center rod can have a pair of arms supporting the support member thereon such that the pair of arms prevents the support member from pivoting relative thereto.

[0015] The surgical anvil assembly may further include a cutting ring positioned about and secured to the support member.

[0016] In some aspects, the surgical anvil assembly can further include a cam latch mounted to the post of the anvil head. The cam latch can be configured to normally bias the anvil head to the second inclined state.

[0017] Other features of the present disclosure will be understood from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various embodiments of the surgical anvil assembly disclosed herein for incorporation into a circular surgical stapling instrument are described below with reference to the accompanying drawings, wherein:

[0019] Figure 1 is a perspective view of an exemplary embodiment of a circular surgical stapling instrument incorporating an embodiment of a surgical anvil assembly of the present disclosure;

[0020] Figure 2 is a perspective view of a circular stapling instrument showing a tool assembly including an anvil assembly separated from an elongated body of the circular stapling instrument;

[0021] Figure 3 is a side cross-sectional view of the tool assembly showing an anvil assembly mounted to a staple cartridge of a housing of the tool assembly;

[0022] Figure 4 is a perspective view of the anvil assembly;

[0023] Figure 5 is an exploded perspective view of the anvil assembly;

[0024] Figure 6 is a side cross-sectional view of the tool assembly showing the anvil assembly mounted on the staple cartridge with the annular knife in an advanced position;

[0025] Figure 7 is a side cross-sectional view of the anvil assembly showing the anvil head in a pivoted or tilted condition;

[0026] Figure 8 is used to combine with Figure 1 A side cross-sectional view of an embodiment of a surgical anvil assembly in a circular stapling instrument;

[0027] Fig.9A yes Figure 8 a first perspective view of an internal component of a locking assembly of an anvil assembly;

[0028] Fig. 9B is a second perspective view of internal components of the locking assembly;

[0029] Fig.10 yes Figure 8 A perspective view of an outer member of a locking assembly;

[0030] Fig.11 yes Figure 8 a side cross-sectional view of an anvil assembly showing the locking assembly in a distal position;

[0031] Fig.12 yes Figure 8 A side cross-sectional view of an anvil assembly showing the locking assembly in a proximal position;

[0032] Fig.13 is used to combine with Figure 1 A perspective view of another embodiment of a surgical anvil assembly in a circular stapling instrument;

[0033] Fig.14 yes Fig.13 A side perspective view of an anvil center rod of an anvil assembly;

[0034] Fig.15 yes Fig.13 A perspective view of a resilient leg of an anvil assembly;

[0035] Fig.16 yes Fig.15 A side view of the elastic leg;

[0036] Fig.17 Yes Insert Fig.14 A side view of a trocar in a center rod of an anvil, with portions shown in phantom;

[0037] Fig.18 Yes Insert Fig.14 A perspective view of a trocar in a center rod of an anvil, with portions shown in phantom;

[0038] Fig.19 is fully inserted Fig.14 A perspective view of a trocar of the anvil center rod, with portions thereof shown in phantom;

[0039] Fig. 20 is used to combine with Figure 1 A side cross-sectional view of another embodiment of a surgical anvil assembly in a circular stapling instrument;

[0040] Fig.21 yes Fig. 20 a proximal perspective view of a ring assembly of an anvil assembly;

[0041] Fig. 22 yes Fig.21 a perspective view of the distal side of the ring assembly;

[0042] Fig.23 yes Fig. 20 a side cross-sectional view of an anvil assembly showing the ring assembly in a distal position;

[0043] Fig.24 is used to combine with Figure 1 A perspective view of components of another embodiment of a surgical anvil assembly in a circular stapling instrument;

[0044] Fig.25 yes Fig.24 a proximal perspective view of a ring assembly of an anvil assembly;

[0045] Fig.26 yes Fig.25 a perspective view of the distal side of the ring assembly;

[0046] Fig. 27 yes Fig.25 A partial side cross-sectional view of a ring assembly;

[0047] Fig.28 yes Fig.24 a side cross-sectional view of an anvil assembly showing the ring assembly in a proximal position;

[0048] Fig.29 yes Fig.24 a side cross-sectional view of an anvil assembly showing the ring assembly in a distal position;

[0049] Fig.30 is used to combine with Figure 1 A side cross-sectional view of another embodiment of a surgical anvil assembly in a circular stapling instrument;

[0050] Fig.31 yes Fig.30 a perspective view of a ring assembly of an anvil assembly;

[0051] Fig.32 yes Fig.31 A perspective cross-sectional view of a ring assembly;

[0052] Fig.33 is used to combine with Figure 1 A perspective view of components of another embodiment of a surgical anvil assembly in a circular stapling instrument;

[0053] Fig.34 yes Fig.33 A perspective view of an anvil head of an anvil assembly;

[0054] Fig.35 yes Fig.33 A perspective view of a ring assembly of an anvil assembly;

[0055] Fig.36 yes Fig.35 A side cross-sectional view of a ring assembly;

[0056] Fig.37 yes Fig.35 A perspective view of a snap collar of the ring assembly;

[0057] Fig.38A yes Fig.35 a perspective view of a proximal side of a support member of a ring assembly;

[0058] Fig.38B yes Fig.38A a perspective view of the distal side of the support member;

[0059] Fig.39 yes Fig.33 a side cross-sectional view of an anvil assembly showing the ring assembly in a proximal position;

[0060] Fig.40 yes Fig.33 a side cross-sectional view of an anvil assembly showing the ring assembly in a distal position;

[0061] Fig.41 is used to combine with Figure 1 A side cross-sectional view of another embodiment of a surgical anvil assembly in a circular stapling instrument;

[0062] Fig.42 yes Fig.41 A perspective view of a distal portion of an anvil center rod of an anvil assembly;

[0063] Fig.43 yes Fig.41 A side view of a linkage arm of a pivot assembly of an anvil assembly;

[0064] Fig.44 yes Fig.41 A side cross-sectional view of an anvil assembly showing the anvil assembly in an inclined state;

[0065] Fig.45 is used to combine with Figure 1 A side cross-sectional view of another embodiment of a surgical anvil assembly in a circular stapling instrument.

[0066] Fig.46 yes Fig.45 an enlarged view of a pivot member of an anvil assembly;

[0067] Fig.47 yes Fig.45 Another side cross-sectional view of the anvil assembly;

[0068] Fig.48 yes Fig.47 an enlarged view of a cam latch of an anvil assembly;

[0069] Fig.49 is used to combine with Figure 1 A perspective view of another embodiment of a surgical anvil assembly in a circular stapling instrument;

[0070] Fig.50 yes Fig.49 a perspective view of a proximal side of an anvil head of an anvil assembly;

[0071] Fig.51 yes Fig.49 a side view of a cam latch of an anvil assembly;

[0072] Fig.52 yes Fig.49 A side cross-sectional view of an anvil assembly showing the anvil head in an inclined state;

[0073] Fig.53 is used to combine with Figure 1 A side cross-sectional view of another embodiment of a surgical anvil assembly in a circular stapling instrument of , showing the ring assembly in a proximal position;

[0074] Fig.54 yes Fig.53 A side cross-sectional view of a surgical anvil assembly showing the ring assembly thereof in a distal position; and

[0075] Fig.55 yes Fig.53 A side cross-sectional view of a surgical anvil assembly showing the ring assembly after the annular knife has been retracted. DETAILED DESCRIPTION

[0076] The anvil assembly disclosed in the present invention for various circular suturing instruments will now be described in detail with reference to the accompanying drawings, wherein the same reference numerals represent the same or corresponding elements in each of the several views. In this specification, the term "proximal" is generally used to refer to that portion of an instrument or its surgical anvil assembly close to a clinician, and the term "distal" is generally used to refer to that portion of an instrument or its surgical anvil assembly away from a clinician. In addition, the term clinician is generally used to refer to medical personnel, including doctors, nurses, and support personnel.

[0077] An exemplary surgical stapling instrument includes a handle assembly, an elongated body or adapter, and a tool assembly coupled to the adapter. The tool assembly includes a housing assembly and an anvil assembly mounted relative to the housing assembly. The anvil assembly includes a center rod releasably coupled to the elongated body and an anvil head pivotably coupled to the center rod. The anvil head can move between a pre-fired untilted or operational state and a post-fired tilted or pivoted state. The anvil head is locked in the pre-fired position until the annular knife of the tool assembly advances, which allows the anvil head to freely pivot or rotate toward the pivoted state relative to the center rod. The present disclosure provides, among other things, various embodiments of a mechanism for unlocking the anvil head from the anvil center rod, and various embodiments of a mechanism for driving the anvil head to rotate when unlocked from the center rod.

[0078] First refer to Figures 1 to 2, an exemplary embodiment of a circular stapling instrument for incorporating a surgical anvil assembly of the present disclosure is shown, and is generally shown as a circular stapling instrument 10. The circular stapling instrument 10 includes a handle 12, an elongated body or adapter 14 extending from the handle 12, and a tool assembly 16 coupled to the adapter 14. The handle 12 can be electric, including a motor and associated gears and linkages to control the operation of the stapling instrument 10. The handle 12 includes a handle 18 and a plurality of actuation buttons 20, which can be activated to control various functions of the stapling instrument 10, including, for example, the approach of the tool assembly 16 and the firing of staples. The handle 18 can support a battery pack (not shown) that provides power to the handle 12. In an embodiment, the circular stapling instrument 10 can be powered by an external power source.

[0079] In an embodiment, the adapter 14 is releasably coupled to the handle 12 and includes a plurality of drive mechanisms (not shown) that transfer power from the handle 12 to the tool assembly 16 in response to the actuation of the actuation button 20 to achieve operation, for example, the approach and firing of the tool assembly 16. The adapter 14 also includes an anvil holder 22 or a trocar that extends from the distal portion of the adapter 14 and can move between a retracted position and an advanced position. The anvil holder 22 can be coupled to the tool assembly 16. Commonly assigned U.S. Patent Nos. 9,247,940; 9,055,943; 8,806,973 and U.S. Publication No. 2015 / 0014392 disclose exemplary embodiments of power handles and adapters suitable for suturing instruments 10, and the patents are incorporated herein by reference in their respective entireties. Alternatively, the elongated body or adapter 14 can be non-detachably fixed to the handle 12.

[0080] It is also contemplated that the handle 12 may be manually powered. Examples of manually powered handle assemblies are described in commonly assigned US Pat. Nos. 8,789,737; 8,424,535; and 8,360,295, which are incorporated herein by reference in their respective entireties.

[0081] Reference Figures 3 to 5 , combined with Figure 2 , the tool assembly 16 includes a housing 24 and a surgical anvil assembly 26 releasably mounted to the housing 24. The housing 24 supports an annular staple cartridge 28 and an annular knife 30 inside the staple cartridge 28. The staple cartridge 28 includes a plurality of staple receptacles 32, each receptacle 32 accommodating a separate staple 34 and a staple pusher 36 for ejecting the staples 34 from the staple cartridge 28 when the instrument 10 is fired.

[0082] The anvil assembly 26 shares common features with the anvil assembly disclosed in commonly assigned U.S. Patent No. 8,540,132, the entire contents of which are incorporated herein by reference. Figures 3 to 5 As shown, the anvil assembly 26 includes an anvil center rod 38 and an anvil head 40 pivotally mounted to the anvil center rod 38. The anvil head 40 is suitable for Figure 4 and 6 The first operating state shown and Figure 7 The anvil center rod 38 includes a pair of distal spaced arms 42 having transverse holes 44 that receive pivot members, such as pivot pins 66, therethrough. The anvil head 40 is pivotally coupled to the distal spaced arms 42 via the pivot pins 66.

[0083] The anvil assembly 26 further includes a plunger 46, a plunger spring 48, and a cam latch or cam plate 50. The plunger 46 is at least partially received within the anvil center rod 38, e.g., between the spacer arms 42, and is spring biased in the distal direction by the plunger spring 48. The plunger 46 includes a plunger finger 52 that engages the cam latch 50 to provide a distal force on the cam latch 50.

[0084] The anvil head 40 includes a housing 54 defining a recess 70 therein, and a post 56 extending proximally from the center of the housing 54. The housing 54 has an anvil tissue contacting surface 58 defining a plurality of staple deformation pockets 72. The post 56 of the anvil head 40 includes a pair of spaced apart post arms 60 defining a slot 62 and a transverse hole 64 extending through the spaced apart post arms 60. As briefly mentioned above, the anvil center rod 38 is at least partially positioned around the post 56 and coupled to the anvil head 40 by a pivot member 66 extending through the distal spaced apart arms 42 of the anvil center rod 38 and the corresponding transverse holes 44, 64 of the post 56 to pivotally couple the anvil head 40 to the anvil center rod 38. Additionally, the cam latch 50 is received within the slot 62 of the post 56 and is coupled to the anvil center rod 38 and the post 56 via a pivot member 66 that extends through a pin opening 68 of the cam latch 50 .

[0085] Now refer to Figures 4 to 6 , the anvil assembly 26 further includes a support member 76 and a cutting ring 78 attached thereto. The support member 76 and the cutting ring 78 move together within the groove 70 of the anvil head 40 upon application of force thereto, such as during advancement of the annular knife 30 of the tool assembly 16 during firing of the instrument 10. The support member 76 includes an annular body 79 and a pair of diametrically opposed fingers 98 extending radially inwardly from the annular body 79. The annular body 79 of the support member 76 is axially movable but pivotally fixed within the groove 70 of the anvil head 40.

[0086] The finger-shaped member 98 is engaged by the spacer arm 42 of the anvil center rod 38 to prevent the support member 76 from moving in the proximal direction and to maintain the anvil head 40 in an operative state (e.g., not tilted) until the annular knife 30 is braked. More specifically, when the support member 76 is in the proximal position, as shown in FIG. Figure 3 As shown, the finger-shaped member 98 of the support member 76 is located at or adjacent to the distal surface of the spacer arm 42 of the anvil center rod 38, thereby preventing the anvil head 40 from rocking or pivoting relative to the anvil assembly 26. The anvil head 40 is allowed to pivot relative to the anvil center rod 38 only after the finger-shaped member 98 is spaced apart from the arm 42 of the anvil center rod 38 distally.

[0087] The support member 76 further includes a pair of diametrically opposed cam carriers 99 extending radially inwardly from the annular body 79. The cam carriers 99 intercept the cam latch 50 therebetween to rotationally secure the cam latch 50 to the support member 76. Thus, when the cam latch 50 rotates or pivots, so do the support member 76 and the anvil head 40 as a whole. The support member 76 can be formed of a hard material such as metal, although other structural materials are contemplated.

[0088] The cutting ring 78 of the anvil assembly 26 includes a disc-shaped annular body 104 that defines a central aperture 106 for receiving the support member 76. Thus, movement of the support member 76 between the un-tilted and tilted states causes corresponding movement of the cutting ring 78. In an embodiment, the cutting ring 78 can be formed by a molding process (e.g., an injection molding process) and can be made of a material having a durometer that allows the annular knife 30 to pierce the annular body 104 and bottom out against the support member 76. Suitable materials for the cutting ring 78 include polypropylene or polyester. Other materials are contemplated.

[0089] Before the stapling apparatus 10 is fired, the support member 76 is in its retracted or proximal position and the cutting ring 78 is secured to the support member 76 in the manner described above. With the support member 76 in the proximal position, the inwardly extending fingers 98 of the support member 76 pass through the spacer arms 42 ( Figure 4 ) engagement, so that the anvil head 40 is maintained in the operative state. As described above, the plunger finger 52 of the plunger 46 of the anvil center rod 38 is positioned to facilitate the cam latch 50 and the anvil head 40 to move about the pivot member 66 toward the tilted state ( Figure 7 However, as will be described, the anvil head 40 is prevented from pivoting until the annular knife 30 is advanced to unlock the locking assembly 100 of the surgical anvil assembly 26 ( Figure 4 , 5 and 8 to 12).

[0090] Reference Figures 8 to 12, the surgical anvil assembly 26 may further include a locking assembly 100 for selectively locking the anvil head 40 in each of the first operating state and the second tilted state. The locking assembly 100 replaces the deformable retainer member of the prior art, such as the retainer member 127 described in U.S. Pat. No. 9,532,781, the entire contents of which are incorporated herein by reference. The deformable retainer member generally supports the support member 76 in a proximal position and deforms to allow the anvil head 40 to tilt when the support member 76 is advanced. Since there is no deformable retainer in this embodiment, the anvil head 40 can be repeatedly moved between the non-tilted and tilted states.

[0091] The locking assembly 100 generally includes an annular inner member or housing 102, an annular outer member 104 surrounding the inner member 102, and a pair of locking elements 106a, 106b movably coupled to the inner member 102. In embodiments, the inner and outer members 102, 104 may take any suitable shape, such as, for example, annular, square, triangular, etc. The inner member 102 is fixedly supported on the distally facing outer surface 41 of the anvil head 40. The anvil head 40 may have a plurality of small holes 108 ( Figure 8 ), which is defined for receiving fasteners (not explicitly shown) that fixedly attach the inner member 102 of the locking assembly 100 to the anvil head 40. The inner member 102 defines a plurality of channels 110 extending transversely therethrough, which are defined for accommodating corresponding locking elements 106a or 106b. Although four channels 110 are shown, it is contemplated that the inner member 102 may have more or less than four channels 110 for accommodating corresponding numbers of locking elements 106a, 106b.

[0092] The locking elements 106a, 106b are received in the channel 110 of the inner member 102 and are arranged directly opposite each other. The locking elements 106a, 106b can be spherical detents that protrude radially outward from the periphery 112 of the inner member 102. In an embodiment, the locking elements 106a, 106b can be any suitable biasing member that is elastically biased radially outward. In an embodiment, as will be described, the locking elements 106a, 106b can remain fixed relative to the inner member 102, while the outer member 104 can be flexible so that the outer member 102 bends outward when contacting the locking elements 106a, 106b when the outer member 104 slides along the inner member 102.

[0093] The outer member 104 of the locking assembly 100 surrounds the inner member 102 and can be moved along a first proximal position ( Fig.11 ) and the second distal position ( Fig.12) therebetween, the outer member 104 abutting the outer surface 41 of the anvil head 40 in a first proximal position, and the outer member 104 being spaced distally from the outer surface 41 of the anvil head 40 in a second distal position. The outer member 104 has an inner surface or inner periphery 114 adjacent to and surrounding the outer periphery 112 of the inner member 102. The inner periphery 114 of the outer member 104 has a lip or flange 116 projecting radially inwardly therefrom for selectively interacting with the locking elements 106a, 106b.

[0094] More particularly, at the first proximal position ( Fig.11 ), the lip 116 of the outer member 104 is disposed proximal to the outer surface of the locking elements 106a, 106b and also overlaps with it. Because the lip 116 of the outer member 104 overlaps with the locking elements 106a, 106b, the locking elements 106a, 106b resist the distal movement of the outer member 104 relative to the inner member 102. In order to move the outer member 104 of the locking assembly 100 distally, a threshold force directed in the distal direction must be applied to the outer member 104 to overcome the elastic force of the locking elements 106a, 106b. When the threshold force is applied, the locking elements 106a, 106b move radially inward relative to the inner member 102, allowing the lip 116 of the outer member 104 to pass over the locking elements 106a, 106b.

[0095] When the outer member 104 is in the second distal position ( Fig.12 ), the locking elements 106a, 106b and the lip 116 of the outer member 104 are engaged and aligned along the transverse axis. Due to the outwardly directed spring bias of the locking elements 106a, 106b, the lip 116 of the outer member 104 and the locking elements 106a, 106b frictionally engage each other, thereby resisting movement of the outer member 104 from the second distal position until a threshold force is applied in the proximal direction.

[0096] The locking assembly 100 further includes a plurality of posts or rods 118 interconnecting the inner member 102 and the support member 76 of the locking assembly 100. The posts 118 are spaced apart from each other in the circumferential direction and extend downwardly (e.g., proximally) from the outer member 104. The posts 118 have distal ends 118b connected to or formed with the outer member 104, intermediate portions 118c extending through corresponding apertures 108 (defined through the anvil head 40), and proximal ends 118a disposed within the recess 70 of the anvil head 40. The proximal end 118a of each post 118 is fixed to the support member 76 so that when the outer member 104 moves relative to the inner member 102, the support member 76 moves with the outer member 104. Thus, when the outer member 104 moves from a first proximal position ( Fig.11 ) toward the second distal position ( Fig.12) moves, the support member 76 moves deeper into the groove 70 of the anvil head 40 and disengages from the distal spacing arm 42 of the anvil center rod 38.

[0097] In operation, the support member 76 with the cutting ring 78 is retained in a proximal position in the groove 70 by the locking assembly 100. In particular, the locking elements 106a, 106b resist distal movement of the outer member 104 of the locking assembly 100 relative to the inner member 102 of the locking assembly 100. Because the support member 76 is fixed to the outer member 104 via the post 118 of the locking assembly 100, distal movement of the support member 76 toward the distal position is also resisted.

[0098] When the anvil head 40 and the staple cartridge 28 ( Figure 3 ), the stapling instrument 10 can be fired to advance the annular knife 30 within the housing 24 from a retracted position recessed within the housing 24 to an advanced position extending into the cutting ring 78 of the anvil assembly 26. When the annular knife 30 engages the cutting ring 78, the cutting ring 78 and the support member 76 exert a distal force on the outer member 104 of the locking assembly 100 via the column 118 of the locking assembly 118. When a threshold force is applied to the outer member 104, the locking elements 106a, 106b are pushed radially inward into the corresponding channels 110 of the inner member 102, allowing the lip 116 of the outer member 104 to pass over the locking elements 106a, 106b when the support member 76 is advanced to the second distal position within the recess 70 of the anvil head 40, as shown in FIG. Fig.11 Once the support member 76 moves toward its second position, the lip 116 of the outer member 104 and the locking elements 106a, 106b frictionally engage one another to selectively secure the outer member 104, and in turn, the support member 76, in the second distal position.

[0099] As the support member 76 moves toward its distal position, the fingers 98 ( Figure 4 and 5 ) is disengaged from the distal spacing arm 42 of the anvil center rod 38, thereby allowing the anvil head 40 to freely pivot relative to the anvil center rod 38. As the anvil head 40 rotates freely, the plunger spring 48 ( Figure 6 ) pushes the plunger 46 in the distal direction, whereby the plunger finger 52 engages the cam latch 50 to rotate the cam latch 50 and the anvil head 40 about the pivot member 66, thereby allowing the anvil head 40 to assume Figure 7 The second tilted state is shown in .

[0100] After the anvil head 40 is moved to the tilted state, the anvil head 40 can be manually moved back toward the first operating state. After the anvil head 40 is moved back to the first operating state (e.g., not tilted), the support member 76 can also be reset to its proximal position. In order to move the support member 76 to the proximal position, a threshold force toward the proximal side can be manually applied to the outer member 104 of the locking assembly 100, which overcomes the static friction between the lip 116 of the outer member 104 and the locking elements 106a, 106b, thereby the outer member 104 moves proximally relative to the inner member 102. Due to the interconnection between the outer member 104 and the support member 76 via the column 118, the support member 76 moves proximally and the outer member 104 returns toward the proximal position.

[0101] When re-entering the proximal position, the finger-shaped member 98 ( Figure 4 and 5 ) reengages the distal spacing arm 42 of the anvil center rod 38, thereby stabilizing the anvil head 40 in the first operating state. It is expected that this process of selectively moving the anvil head 40 relative to the anvil center rod 38 can be repeated indefinitely.

[0102] Reference Figures 13 to 19 , another embodiment of a surgical anvil assembly 126 is shown, similar to the above-described anvil assembly 26. Due to the similarity between the anvil assembly 126 of the present embodiment and the above-described anvil assembly 26, only those elements of the anvil assembly 126 deemed necessary to clarify the differences from the anvil assembly 26 will be described in detail.

[0103] Specific reference Fig.13 and 14 , the anvil assembly 126 includes an anvil center rod 138 and an anvil head 140 similar to the anvil head 40 described above. The anvil head 140 is pivotally mounted to the anvil center rod 138. The anvil center rod 138 may include a pair of distal spacer arms 142 and an elongated proximal body portion 144 extending proximally from the pair of distal spacer arms 142. The distal spacer arms 142 define a transverse hole 143 through their distal ends for accommodating a pivot member (not explicitly shown) similar to the pivot member 66 described above. The proximal body portion 144 of the anvil center rod 138 is configured to be releasably coupled to an anvil retainer or a trocar, for example Figure 2 Anvil holder 22 is shown in FIG. A detailed description of anvil holders can be found in U.S. Patent No. 7,364,060, the entire contents of which are incorporated herein by reference.

[0104] The proximal body portion 144 of the anvil center rod 138 defines a pair of diametrically opposed slots 150a, 150b. The slots 150a, 150b extend proximally from a position adjacent the proximal end of the distal spacing arm 142 and terminate distally of the proximal end of the proximal body portion 144. As will be described below, the slots 150a, 150b are sized to receive a pair of legs 152, 154 configured to releasably capture the anvil retainer 22 between them.

[0105] Reference Figures 15 to 19 , the legs 152, 154 of the anvil center rod 138 are received in the corresponding slots 150a, 150b in the proximal body portion 144 of the anvil center rod 138. Each of the legs 152, 154 is made of a material that allows the legs 152, 154 to bend around their proximal ends 152a, 154a in a spring-like manner. It is expected that the thickness of the legs 152, 154 can be increased or reduced to adjust their flexibility. The distal ends 152b, 154b of the legs 152, 154 are attached to the inner periphery 156 of the proximal body portion 144 by, for example, laser welding, and the proximal ends 152a, 154a of the legs 152, 154 are free to pivot relative to the corresponding distal ends 152b, 154b.

[0106] In embodiments, the legs 152, 154 can be attached to the proximal body portion 144 at any suitable location along the legs 152, 154 using any suitable fastening method. It will be appreciated that adjusting the location at which the legs 152, 154 are attached to the proximal body portion 144 will change the force required to bend the legs 152, 154. The proximal ends 152a, 154a of the legs 152, 154 include radially inwardly extending tabs or detents 158, 160. The detents 158, 160 are configured to snap-fit ​​into engagement with the lip 23 defined by the proximal end of the cannula 22, as will be described in further detail below.

[0107] Each of the legs 152, 154 has an outer profile that matches the outer profile of the proximal body portion 144, such that the legs 152, 154 do not protrude outwardly from the proximal body portion 144. Each of the legs 152, 154 has an inner profile that substantially matches the outer profile of the trocar 22. As such, when the legs 152, 154 are disposed within the respective slots 150a, 150b of the proximal body portion 144, the legs 152, 154 cooperatively define a cavity 162 therebetween that is sized to receive the trocar 22.

[0108] During manufacturing, the legs 152, 154 are received within the corresponding slots 150a, 150b of the proximal body portion 144, and the distal end 152b, 154b of each of the legs 152, 154 is welded (e.g., laser welded) to the inner periphery 156 ( Fig.18 ).like Fig.17 and 18 As shown, the trocar 22 is Fig.18 The trocar 22 is advanced distally in the direction indicated by the arrow "A" through the proximal body portion 144, whereby the tapered outer surface 25 of the base of the trocar 22 engages the detents 158, 160 at the proximal ends 152a, 154a of the legs 152, 154, thereby causing the legs 152, 154 to bend outwardly. Fig.19 As shown, the trocar 22 continues to be advanced distally until the lip 23 defined at the base of the trocar 22 passes over the detents 158, 160 of the legs 152, 154, causing the detents 158, 160 to snap into place proximally of the lip 23 of the trocar 22, thereby capturing the trocar 22 in the cavity 162 defined between the legs 152, 154. The inwardly directed resilient bias of the legs 152, 154 axially secures the trocar 22 within the proximal body portion 144.

[0109] Reference Figures 20 to 23 , another embodiment of a surgical anvil assembly 226 similar to the anvil assemblies described above is shown. Due to the similarity between the anvil assembly 226 of this embodiment and the anvil assemblies described above, only those elements of the anvil assembly 226 deemed necessary to clarify the differences from the other anvil assemblies will be described in detail.

[0110] The anvil assembly 226 includes an anvil center rod 238, an anvil head 240 pivotally mounted to the anvil center rod 238, and a ring assembly 250 for selectively unlocking the anvil head 240 from the anvil center rod 238. The anvil head 240 is configured to pivot relative to the anvil center rod 238 between a first operating state and a second pivot or tilted state. The anvil head 240 defines a recess 270 therein having a post 256 of the anvil head 240 extending proximally therefrom. The post 256 of the anvil head 240 is pivotally coupled to the distal end of the anvil center rod 238.

[0111] The ring assembly 250 is received within a groove 270 defined in the anvil head 240 and generally includes a support member 276 and a cutting ring 278 disposed about and secured to the support member 276. The ring assembly 240 is movable within the groove 270 of the anvil head 240 when a force is applied thereto, such as during advancement of an annular knife, such as Figure 3 and 6Annular knife 30 shown in FIG. Support member 276 of ring assembly 250 has ring body 279 and annular lip 252, annular lip 252 extends radially outward from the distal end of ring body 279 to support cutting ring 278 thereon. Ring body 279 defines central opening 294 for receiving post 256 of anvil head 240. The central opening 294 is sized to allow support member 276 to be moved around post 256 from a pre-fired, retracted or proximal position ( Fig. 20 ) moves to a post-launch, forward, or distal position ( Fig.23 ).

[0112] The support member 276 further includes a pair of diametrically opposed finger-shaped pieces 298 extending inwardly from the ring body 279 into the central opening 294. The finger-shaped pieces 298 are engaged by the distal end of the anvil center rod 238 to prevent the support member 276 from moving in the proximal direction and to maintain the anvil head 40 in an operative state (e.g., not tilted) in a manner similar to that described above. Pivotal movement of the anvil head 240 relative to the anvil center rod 238 is allowed only after the finger-shaped pieces 298 are spaced apart distally from the distal end of the anvil center rod 238. As will be described below, the support member 276 is limited from moving distally away from the proximal position by the frangible portion 254 of the cutting ring 278. The support member 276 can be formed of a hard material such as metal, but other structural materials can be envisioned.

[0113] The cutting ring 278 of the ring assembly 250 includes a disc-shaped annular body 257, which defines a central aperture 258 for receiving the support member 276. The annular body 257 can be press-fitted onto the support member 276. Therefore, the movement of the support member 276 between the proximal position and the distal position causes a corresponding movement of the cutting ring 278. In an embodiment, the cutting ring 278 can be formed by a molding process (e.g., an injection molding process) and can be made of a material with a durometer that allows the annular knife 30 to pierce the annular body 257 and bottom out against the annular lip 252 of the support member 276. In an embodiment, the cutting ring 278 can be made of a material that prevents the annular knife 30 from advancing therethrough, or is coated with a material that allows the annular knife 30 to advance therethrough. Suitable materials for the cutting ring 278 include polytetrafluoroethylene, polypropylene, or polyester. Other materials are contemplated.

[0114] Best as Fig.21 As shown, the cutting ring 278 includes a plurality of pockets 258 formed in a bottom or proximal surface 260 thereof. The pockets 258 are shown as having a curved shape, but it is contemplated that the pockets 258 may take on any suitable shape. The cutting ring 278 further includes a plurality of frangible portions or legs 254 extending distally from a top or distal surface 262 of the annular body 257 of the cutting ring 278. Fig. 20As shown, the frangible legs 254 suspend the annular body 257 of the cutting ring 278 in the groove 270 of the anvil head 240 to maintain the ring assembly 250 in a proximal position. The frangible legs 254 can have a curved shape and are positioned directly above the corresponding pockets 258. The frangible legs 254 are configured to deform (e.g., collapse) into the corresponding pockets 258 when a threshold distal force is applied to the ring assembly 250.

[0115] To facilitate deformation of the frangible legs 254, the distal surface 262 of the annular body 257 of the cutting ring 278 defines a pair of annular notches 264 disposed on opposite sides of the frangible legs 254. The notches 264 may have an arcuate shape, a V-shape, or any suitable cross-sectional configuration. The frangible legs 254 of the cutting ring 278 may be made of the same or different material than the annular body 257 of the cutting ring 278. For example, the frangible legs 254 may be made of polytetrafluoroethylene, polypropylene, or polyester.

[0116] In operation, when firing the annular blade 30 ( Figure 3 and 6 ), the ring assembly 250 (including the support member 276 and the cutting ring 278) is in its retracted or proximal position. In the proximal position, the frangible legs 254 of the cutting ring 278 engage the inner surface 272 of the anvil head 240, thereby maintaining the ring assembly 250 in the proximal position, such as Fig. 20 With the ring assembly 250 in the proximal position, the inwardly extending fingers 298 of the support member 276 are engaged by the anvil center rod 238 so that the anvil head 240 is maintained in the first operative state and is prevented from pivoting relative to the anvil center rod 238 .

[0117] When the annular knife 30 ( Figure 3 and 6 ), the annular knife 30 engages the annular body 257 of the cutting ring 278 of the ring assembly 250. The annular knife 30 pierces the annular body 257 of the cutting ring 278 and eventually engages the annular lip 252 of the support member 276. The force applied by the annular knife 30 on the ring assembly 250 is transmitted to the frangible legs 254 of the cutting ring 278, which are compressed between the annular body 257 of the cutting ring 278 and the inner surface 272 of the anvil head 240. When the annular knife 30 applies a threshold distal force on the ring assembly 250, the frangible legs 254 of the cutting ring 278 separate or break away from the annular body 257 of the cutting ring 278 along the annular notch 264.

[0118] As the frangible legs 254 of the cutting ring 278 separate from the annular body 257 of the cutting ring 278, the continued distal force exerted on the ring assembly 250 by the annular knife 30 drives the annular body 257 of the cutting ring 278 and the support member 276 distally, so that the frangible legs 254 of the cutting ring 278 collapse or fall into corresponding pockets 258 in the annular body 257 of the cutting ring 278, as shown in FIG. Fig.23 As the ring assembly 250 is advanced toward the distal position, the inwardly extending fingers 298 of the support member 276 disengage from the arms of the anvil center rod 238, allowing the anvil head 240 to pivot relative to the anvil center rod 238. It is contemplated that the anvil head 240 can automatically pivot relative to the anvil center rod 238 in the same manner as described above. In embodiments, the anvil head 240 can be automatically or manually pivoted by any suitable mechanism, such as those described in the patents incorporated herein by reference.

[0119] Reference Figures 24 to 29 , another embodiment of a surgical anvil assembly 326 similar to the above-described surgical anvil assemblies is shown. Due to the similarity between the anvil assembly 326 of this embodiment and the above-described anvil assemblies, only those elements of the anvil assembly 326 deemed necessary to clarify the differences from the previous anvil assemblies will be described in detail.

[0120] The anvil assembly 326 generally includes an anvil center rod (not shown) similar to the anvil center rod described above, an anvil head 340 configured to be pivotally mounted to the anvil center rod, and a ring assembly 350 configured to selectively unlock the anvil head 340 from the anvil center rod. The anvil head 340 is configured to pivot relative to the anvil center rod between a first operating state and a second pivoted or tilted state.

[0121] The anvil head 340 defines a recess 370 ( Fig.28 ), which has a post 356 of the anvil head 340 extending proximally therefrom. The post 356 of the anvil head 340 is configured to be pivotally coupled to the distal end of the anvil center rod. The groove 370 of the anvil head 340 is sized to slidably receive the ring assembly 350. The anvil head 340 includes an annular inner peripheral surface 372 that partially defines the groove 370 and an inner ring or lock 374 extending radially inward from the inner peripheral surface 372. The inner ring 374 resists but does not prevent the distal movement of the ring assembly 350 through the groove 370 of the anvil head 340.

[0122] The ring assembly 350 generally includes a support member 376 similar to the support member described above, an annular cup 352 nested in the support member 376, and a cutting ring 378 nested in the annular cup 352. The ring assembly 350 is formed when a force is applied thereto, such as when the annular knife 30 ( Fig.28 and 29) during advancement. The support member 376 defines a central opening 394 for receiving the post 356 of the anvil head 340. The central opening 394 is sized to facilitate movement of the support member 376 about the post 356 within the recess 370 of the anvil head 340 from the pre-fired, retracted, or first position. As will be described, the support member 376 is held in the proximal position by the inner ring 374 of the anvil head 340, which supports the annular cup 352 in the proximal position ( Fig.28 ).

[0123] The support member 376 includes a pair of diametrically opposed finger-shaped members 398 that extend inwardly into the central opening 394. The finger-shaped members 398 engage with the anvil center rod to prevent the support member 376 from moving in the proximal direction and to maintain the anvil head 340 in an operative state (e.g., not tilted). Pivotal movement of the anvil head 340 relative to the anvil center rod is permitted only after the finger-shaped members 398 are spaced apart distally from the anvil center rod.

[0124] The support member 376 of the ring assembly 350 further includes an annular wall or ring 354, and a disc-shaped platform 357 extending radially outward from a distal portion of the annular wall 354. The annular wall 354 has a lip 358 extending radially inward from a proximal portion thereof. The lip 358 is configured to engage with the annular cup 352 (e.g., by a snap-fit ​​engagement) to hold the annular cup 352 and the support member 376 together. The support member 376 can be formed of a hard material such as metal, although other structural materials are contemplated.

[0125] The annular cup 352 of the ring assembly 350 supports the cutting ring 378 therein and guides the annular knife 30 into the cutting ring 378 to prevent partial or offset cutting of the cutting ring 378. The annular cup 352 is nested with the support member 376 by being captured between the inner peripheral surface 372 of the anvil head 340 and the support member 376. The annular cup 352 generally includes an annular outer wall 360, an annular first inner wall 362, and a disc-shaped base 364 interconnecting the outer wall 360 and the first inner wall 362. The outer wall 360, the base 364 and the first inner wall 362 together define a cavity or annular chamber 366, which is sized to receive the cutting ring 352.

[0126] Best as Figures 24 to 27 As shown, the outer wall 360 of the annular cup 352 has an annular outer peripheral surface 360a and an annular inner peripheral surface 360b, wherein the thickness of the annular wall 360 is defined between them. An outer lip 368 extends radially outward from the outer peripheral surface 360a of the outer wall 360. The outer lip 368 of the outer wall 360 overlaps with the inner ring 374 of the anvil head 340 to support the ring assembly 350 in the proximal position and resist the movement of the ring assembly 350 toward the distal position.

[0127] The outer wall 360 may have a plurality of slits 380 defined therein. The slits are arranged circumferentially around the outer wall 360. The slits 380 provide the outer wall 360 with flexibility so that as the ring assembly 350 is advanced distally through the groove 370 of the anvil head 340, the outer wall 360 may bend or flex radially inward to snap into place under the inner ring 374 of the anvil head 340. In embodiments, instead of or in addition to having the slits 380, the outer wall 360 may be made of a flexible material to facilitate radial contraction of the outer wall 360 during assembly to the anvil head 340.

[0128] The outer wall 360 of the annular cup 352 also includes a chamfered surface 382 that slopes downward (eg, distally) from the most proximal surface of the outer wall 360. An annular inner edge 384 ( Fig. 27 ) is disposed radially inwardly of the inner circumferential surface 360b of the outer wall 360 such that the chamfered surface 382 defines an undercut or overhang 386. The undercut 386 covers the outer edge 388 of the cutting ring 378 to capture the cutting ring 378 in the annular chamber 366 of the annular cup 352. Thus, as the annular knife 30 is advanced, the chamfered surface 382 guides or redirects the knife 30 inwardly and makes contact with the cutting ring 378 at a position radially inwardly of the outer edge 388 of the cutting ring 378. This eliminates the possibility of a line-to-line suture condition.

[0129] The position at which the knife 30 is expected to contact the cutting ring 378 can be adjusted by adjusting the depth of the undercut 386. For example, to ensure that the knife 30 contacts the cutting ring 378 at a more radially inward position, the depth of the undercut 386 in the outer wall 360 can be increased. In addition to or as an alternative to increasing the depth of the undercut 386, the annular inner edge 384 of the chamfered surface 382 can extend radially inwardly relative to the inner circumferential surface 360b of the outer wall 360. A greater distance, so that the knife 30 contacts the cutting ring 378 at a more radially inward position.

[0130] The annular cup 352 also includes an annular second inner wall 390 disposed radially inward of the first inner wall 362. The second inner wall 390 can be coupled to the first inner wall 362 via a plurality of bridging members 392 that allow the second inner wall 390 to bend relative to the first inner wall 362. The second inner wall 390 can also include a plurality of slits 395 defined therein. The slits 395 are arranged circumferentially around the second inner wall 390 to further facilitate bending of the second inner wall 390. To assemble the annular cup 352 to the support member 376, the second inner wall 390 of the annular cup 352 is bent radially inward and captured below the lip 358 of the support member 376.

[0131] The cutting ring 378 of the ring assembly 350 is received in the annular chamber 366 of the annular cup 352 between the outer wall 360 of the annular cup 352 and the first inner wall 362 of the annular cup 352. The outer edge 388 of the cutting ring 378 is disposed below the undercut 386 of the chamfered surface 382 of the annular cup 352. It is contemplated that the cutting ring 378 may be press-fit onto the annular cup 352. Thus, movement of the annular cup 352 between the proximal position and the distal position causes corresponding movement of the cutting ring 378. In an embodiment, the cutting ring 378 may be formed by a molding process (e.g., an injection molding process) and extend through a plurality of apertures 397 ( Fig.26 ).

[0132] The cutting ring 378 can be made of a material having a durometer that allows the annular knife 30 to penetrate the cutting ring 378 and bottom out against the base 364 of the annular cup 352. In this way, all of the annular cup 352 or selected portions thereof (e.g., the chamfered surface 382 and the base 364) are made of a harder material than the cutting ring 378. Suitable materials for the cutting ring 378 include polytetrafluoroethylene, polypropylene, or polyester. Other materials are contemplated.

[0133] In operation, prior to firing a circular stapling instrument having a surgical anvil assembly 326 of the presently described embodiment, the ring assembly 350 including the support member 376, the annular cup 352, and the cutting ring 378 is in its retracted or proximal position, as shown in FIG. Fig.28 The outer lip 368 of the outer wall 360 of the annular cup 352 overlaps the inner ring 374 of the anvil head 340 to support the ring assembly 350 in the proximal position. With the ring assembly 350 in the proximal position, the inwardly extending fingers 398 of the support member 376 are engaged by the anvil center rod to maintain the anvil head 340 in the first operating state, as described above.

[0134] When the stapling instrument is actuated, the annular knife 30 is advanced into engagement with the cutting ring 378 of the ring assembly 350. In some cases, a section of the annular knife 30 may not be vertically aligned with the cutting ring 378 (e.g., disposed radially outward). In these cases, as the knife 30 is advanced, the knife 30 engages the chamfered surface 382 of the annular cup 352, which guides the knife 30 radially inward into vertical alignment with the cutting ring 378. Because the chamfered surface 382 of the annular cup 352 is suspended from the cutting ring 378, the knife 30 is brought into contact with the cutting ring 378 radially inward of the outer edge 388 of the cutting ring 378.

[0135] As the advancement of the knife 30 continues, the knife 30 pierces the cutting ring 378 and eventually engages the base 364 of the annular cup 352, as shown in FIG. Fig.29The force applied by the knife 30 causes the outer wall 360 of the annular cup 352 to bend or flex inwardly to pass over the inner ring 374 of the anvil head 340. The annular cup 352 is then driven distally along with the cutting ring 378 and the support member 376 toward a distal position.

[0136] As the ring assembly 350 advances toward the distal position, the inwardly extending fingers 398 of the support member 378 disengage the anvil center rod, allowing the anvil head 340 to pivot relative to the anvil center rod. It is contemplated that the anvil head 340 can be configured to automatically pivot relative to the anvil center rod in any manner described herein. In an embodiment, the anvil head 340 can pivot by any suitable pivot mechanism, whether automatic or manual.

[0137] Reference Figures 30 to 32 , another embodiment of a surgical anvil assembly 426 similar to the anvil assembly described above is shown. Due to the similarity between the anvil assembly 426 of this embodiment and the anvil assemblies described above, only those elements of the anvil assembly 426 deemed necessary to clarify the differences from the anvil assemblies described above will be described in detail.

[0138] The anvil assembly 426 generally includes an anvil center rod (not shown) similar to the anvil center rod described above, an anvil head 440 pivotally mounted to the anvil center rod, and a ring assembly 450 configured to selectively unlock the anvil head 440 from the anvil center rod. The anvil head 440 is configured to pivot relative to the anvil center rod between a first operating state and a second pivot or tilted state. The anvil head 440 defines a recess 470 therein for receiving the ring assembly 450. The anvil head 440 includes an annular inner peripheral surface 472 that partially defines the recess 470.

[0139] The anvil head 440 may include a frangible retainer member (not shown) similar to the retainer member 127 described in U.S. Pat. No. 9,532,781, the entire contents of which have been incorporated by reference above. The frangible retainer member may be disposed in a groove 470 of the anvil head 440 between an inner peripheral surface 472 of the anvil head 440 and the ring assembly 450, such that when a threshold distal force is applied to the ring assembly 450, the frangible retainer collapses, allowing distal advancement of the ring assembly 450 and the annular knife 30.

[0140] The ring assembly 440 is received within a groove 470 defined in the anvil head 440 and generally includes a support member 476, a first cutting ring 452 nested in the support member 476, and a second cutting ring 478 nested in the first cutting ring 452. The ring assembly 450 moves within the groove 470 of the anvil head 440 when a force is applied thereto (e.g., during advancement of the annular knife 30).

[0141] The support member 476 defines a central opening 494 for receiving the column 456 of the anvil head 440. The size of the central opening 494 is made to facilitate the support member 476 to move from the pre-fired, retracted or first position to the post-fired, advanced or second position in the groove 470 of the anvil head 440 around the column 456. The support member 476 similar to the above-mentioned support member includes a pair of fingers (not explicitly shown) extending inwardly into the central opening 494. The fingers are engaged by the anvil center rod to prevent the support member 476 from moving in the proximal direction and keep the anvil head 440 in an operating state (e.g., not tilted). Only after the fingers of the support member 476 are spaced apart from the anvil center rod distally, the anvil head 440 is allowed to pivot relative to the anvil center rod, as described above.

[0142] The support member 476 further includes an annular wall or ring 454 and a disc-shaped platform 457 extending radially outward from a distal portion of the annular wall 454. The annular wall 454 has a lip 458 extending radially inward from a proximal portion thereof. The lip 458 is configured to engage (e.g., by snap-fit ​​engagement) the first cutting ring 452 to hold the first cutting ring 452 with the support member 476. The support member 476 can be formed of a hard material such as metal, although other structural materials are contemplated.

[0143] The first cutting ring 452 of the ring assembly 450 supports the second cutting ring 476 therein and provides a surface on which the suture staples are cut. The first cutting ring 452 is made of a first material, such as a hard plastic, which resists being pierced by the annular knife 30. The first cutting ring 452 is nested with the support member 476 by being intercepted between the inner peripheral surface 472 of the anvil head 440 and the support member 476. The first cutting ring 452 includes a proximal portion 452a, a distal portion 452b, and an annular cutout or groove 452c disposed therebetween. The annular groove 452c is defined in the outer peripheral surface 460 of the first cutting ring 452 and intercepts the second cutting ring 478 therein.

[0144] The first cutting ring 452 further defines an annular groove 462 in its proximal portion 452a, which extends circumferentially along the proximal surface 464 of the first cutting ring 452. Although the groove 462 is shown as having a V-shaped configuration, it is contemplated that the groove 462 may have any suitable configuration, such as a U-shape or a square shape. The groove 462 is vertically aligned with the annular groove 452c of the first cutting ring 452 and is configured to place the annular knife 30 ( Fig.32 ) is directed radially inwardly toward the apex 466 of the groove 462.

[0145] The proximal portion 452a of the first cutting ring 452 has a reduced thickness defined between the apex 466 of the groove 462 and the annular groove 452c. Thus, when the annular knife 30 is advanced distally to the proximal portion 452a of the first cutting ring 452, the annular knife 30 cuts through the proximal portion 452a of the first cutting ring 452 along a vertical path "P" that runs through the groove 462 of the first cutting ring 452. The depth of the groove 462 can be increased to increase the force required for the annular knife 30 to cut therethrough, or decreased to reduce the force required for the annular knife 30 to cut therethrough.

[0146] The second cutting ring 478 of the ring assembly 450 is received in the annular groove 452c of the first cutting ring 452. As described above, the second cutting ring 478 is vertically aligned with the groove 462 of the first cutting ring 452 so that the groove 462 of the first cutting ring 452 guides the annular knife 30 into the second cutting ring 478 at a radially inward position of the outer peripheral surface of the second cutting ring 478. It is expected that the second cutting ring 478 can be press-fit into the annular groove 452c of the first cutting ring 452. Therefore, the movement of the first cutting ring 452 between the proximal position and the distal position causes a corresponding movement of the second cutting ring 478. The relatively hard first cutting ring 452 provides a surface on which the annular knife 30 can cut through the staples without being dragged into the relatively soft second cutting ring 478, which is used to cleanly cut tissue.

[0147] In an embodiment, the second cutting ring 478 can be formed by a molding process (e.g., an injection molding process). The second cutting ring 478 can be made of a material having a durometer that allows the annular knife 30 to pierce the second cutting ring 478 and bottom out against the distal portion 452b of the first cutting ring 452b. In this way, the second cutting ring 478 is made of a softer material than the first cutting ring 452. Suitable materials for the second cutting ring 478 include polytetrafluoroethylene, polypropylene, or polyester. Other materials are contemplated.

[0148] In operation, before firing the circular stapling instrument having the surgical anvil assembly 426 of the presently described embodiment, the ring assembly 450 comprising the support member 476, the first cutting ring 452 and the second cutting ring 478 is in its retracted or proximal position. A frangible retainer member (not explicitly shown) is inserted between the support member 476 and the inner surface 472 of the anvil head 440 to support the ring assembly 450 in the proximal position. With the ring assembly 450 in the proximal position, the inwardly extending fingers of the support member 476 are engaged by the anvil center rod so that the anvil head 440 is maintained in the first operating state.

[0149] When the stapling instrument is actuated, the annular knife 30 advances to the inclined surfaces 462a, 462b (462a, 462b) defining the groove 462 of the first cutting ring 452. Fig.31 ) are engaged. Inclined surfaces 462a, 462b guide the knife 30 radially inwardly into vertical alignment with the center portion of the second cutting ring 478. The annular knife 30 moves through the slot 462 and contacts the apex 466 of the slot 462, transmitting a distal force to the frangible retainer member. When a threshold force is applied to the frangible retainer member, the frangible retainer member collapses, allowing the ring assembly 450 to move distally through the recess 470 of the anvil head 440.

[0150] As the ring assembly 450 advances toward the distal position, the inwardly extending fingers of the support member 476 disengage from the anvil center rod, allowing the anvil head 440 to pivot relative to the anvil center rod. It is contemplated that the anvil head 440 may be configured to automatically pivot relative to the anvil center rod in any manner described herein. In an embodiment, the anvil head 440 may pivot by any suitable pivot mechanism, whether automatic or manual.

[0151] As the advancement of the annular knife 30 continues, the annular knife 30 cuts through the proximal portion 452a of the first cutting ring 452, cuts through any tissue and staples along its path, and separates the outer circumferential segment of the proximal portion 452a of the first cutting ring 452 from the remainder of the proximal portion 452a of the first cutting ring 452. It is contemplated that the outer circumferential segment of the first cutting ring 452 remains adhered to the outer surface of the annular knife 30 by friction. As the advancement of the annular knife 30 continues, the annular knife 30 cuts through the second cutting ring 478 and eventually descends to the lowest point on the distal portion 452b of the first cutting ring 452. In an embodiment, the frangible retainer member may be configured to collapse after the annular knife 30 cuts through the proximal portion 452a of the first cutting ring 452, but not before.

[0152] Reference Figures 33 to 40 , another embodiment of a surgical anvil assembly 526 similar to the anvil assembly described above is shown. Due to the similarity between the anvil assembly 526 of this embodiment and the anvil assembly described above, only those elements of the anvil assembly 526 deemed necessary to clarify the differences from the anvil assembly described above will be described in detail.

[0153] Reference Fig.33 and 34 , the anvil assembly 526 generally includes an anvil center rod (not shown) similar to the anvil center rod described above, an anvil head 540 pivotally mounted to the anvil center rod, and a ring assembly 550 configured to selectively unlock the anvil head 540 from the anvil center rod. The anvil head 540 is configured to pivot relative to the anvil center rod between a first operating state and a second pivoted or tilted state.

[0154] The anvil head 540 defines a recess 570 therein, the recess 570 being sized to receive the ring assembly 550. The anvil head 540 includes a post 556 centrally located within the recess 570 and projecting proximally from the base of the recess 570. The post 556 pivotally couples the anvil head 540 to the anvil center rod. For example, the post 556 of the anvil head 540 may be pivotally coupled to a pair of distal spaced arms of the anvil center rod. The post 556 has a body 522 having an annular ridge 524 projecting radially outward therefrom. The annular ridge 524 is configured to selectively hold the ring assembly 550 in a pre-fired proximal position. The body 522 of the post 556 defines an annular recess 526 disposed below or distal to the annular ridge 524.

[0155] The ring assembly 550 is received within a groove 570 defined in the anvil head 540 and generally includes a snap collar 552 engaged to the body 522 of the post 556, a support member 576 supported on the snap collar 552, and a cutting ring 578 captured between the snap collar 552 and the support member 576. The ring assembly 550 moves within the groove 570 when a force is applied thereto (e.g., during advancement of an annular knife, such as the annular knife 30 ( Figure 3 and Figure 6 ).

[0156] Specific reference Figures 35 to 37 , the snap collar 552 of the ring assembly 550 is configured to selectively maintain the ring assembly 550 in a proximal position, but allow the ring assembly 550 to move toward the distal position when a threshold distal force is applied thereto. The snap collar 552 can be an integrally formed plastic block, or can be composed of multiple connected components. The snap collar 552 includes a plurality of horizontally extending support surfaces or flanges 554, and a plurality of vertical extensions 558 inserted between each pair of adjacent flanges 554. In this way, the flanges 554 and the vertical extensions 558 are alternately arranged around the circumference of the snap collar 552. The snap collar 552 can include four flanges 554, which are circumferentially arranged around the snap collar 552 and spaced 90° from each other. Similarly, the snap collar 552 can include four vertical extensions 558, which are circumferentially arranged around the snap collar 552 and spaced 90° from each other. It is contemplated that the snap collar 552 may have more or less than four flanges 554 and vertical extensions 558 .

[0157] The flange 554 of the snap collar 552 may be planar and support the support member 576 thereon ( Fig.36), so that distal movement of the support member 576 causes distal movement of the snap collar 552. The vertical extensions 558 of the snap collar 552 can extend proximally at a perpendicular angle relative to the flange 554. The vertical extensions 558 each include an annular inner lip 560 extending radially inwardly therefrom, and an annular outer lip 562 extending radially outwardly therefrom. When the ring assembly 550 is in the proximal position, the annular inner lip 560 is supported on the annular flange 524 of the post 556 of the anvil head 540. The annular inner lip 560 of the snap collar 552 resists movement of the ring assembly 550 toward the distal position until a threshold distal force causes outward bending of the vertical extensions 558, disengaging the annular inner lip 560 of the snap collar 552 from the annular flange 524 of the post 556 of the anvil head 540. The annular outer lip 562 of the snap collar 552 covers the proximal surface of the cut ring 578 to prevent the cut ring 578 from moving relative to the snap collar 552 .

[0158] Reference Fig.35 , 36 , 38A and 38B, the support member 576 includes a ring body 580 defining a central opening 594, a pair of diametrically opposed tabs 582 extending radially inwardly from the ring body 594 into the central opening 594, and a pair of diametrically opposed fingers 598 extending inwardly into the central opening 594. The central opening 594 receives the post 556 of the anvil head 540 and is sized to facilitate movement of the support member 576 about the post 556 from the pre-fired, retracted, or first position to the post-fired, advanced, or second position within the recess 570 of the anvil head 540. The support member 576 is retained in the proximal position by engagement of the snap collar 552 with the annular flange 524 of the post 556.

[0159] The tabs 582 of the support member 576 are supported on a first pair of diametrically opposed flanges 554 of the buckle 552. The tabs 582 of the support member 576 are configured to transmit the distal force applied by the advancement of the annular knife 30 to the buckle collar 552. The fingers 598 of the support member 576 extend radially inwardly from the annular body 580 to a greater extent than the tabs 582 of the support member 576 and are received in the cutouts 528 in the body 522 of the post 556. The fingers 598 of the support member 576 have a first portion 598a extending horizontally from the ring body 580 of the support member 576, and a second portion 598b extending vertically upward or proximally from the first portion 598a. The first portion 598a of each finger 598 is supported on a second pair of diametrically opposed flanges 554 of the buckle collar 552.

[0160] The second portion 598b of the finger 598 is engaged by the anvil center rod to prevent the support member 576 from moving in the proximal direction and to maintain the anvil head 540 in an operative state (e.g., not tilted). Pivotal movement of the anvil head 540 relative to the anvil center rod is permitted only after the finger 598 of the support member 576 is spaced apart distally from the anvil center rod. The support member 576 can be stamped from a hard material such as metal, but other structural materials are contemplated.

[0161] Reference Fig.33 , 35 , 36, 39 and 40, the cutting ring 578 of the ring assembly 550 is supported on the support member 576 and has an inner peripheral surface 590 that is captured between the annular outer lip 562 of the snap collar 552 and the tabs 582 and fingers 598 of the support member 576. Thus, proximal or distal movement of the support member 576 results in corresponding proximal or distal movement of the snap collar 552 and the cutting ring 578. The cutting ring 578 has a plurality of surface features 596 protruding from its outer peripheral surface. The surface features 596 are press-fitted under the inner ring 574 of the anvil head 540 to retain the ring assembly 550 in the groove 570.

[0162] The cutting ring 578 can be made of a material having a durometer that allows the annular knife 30 to pierce the cutting ring 578 and bottom out against the ring body 580 of the support member 576. As such, the support member 576 can be made of a harder material than the cutting ring 578. Suitable materials for the cutting ring 578 include polytetrafluoroethylene, polypropylene, or polyester. Other materials are contemplated.

[0163] In operation, prior to firing a circular stapling instrument having a surgical anvil assembly 526 of the presently described embodiment, the ring assembly 550 including the support member 576, the snap ring 552, and the cutting ring 578 is in its retracted or proximal position in the recess 570 of the anvil head 540, as shown in FIG. Fig.39 The annular inner lip 560 of the snap collar 552 is supported on the annular flange 524 of the post 556 of the anvil head 540, and the surface feature 596 of the cutting ring 578 is supported on the inner ring 574 of the anvil head 540. With the ring assembly 550 in the proximal position, the inwardly extending fingers 598 of the support member 576 are engaged by the anvil center rod so that the anvil head 540 is maintained in the first operating state.

[0164] When the stapling instrument is actuated, the annular knife advances to engage the cutting ring 578 of the ring assembly 550, which transmits a distal force to the support member 576, which in turn transmits a distal force to the snap collar 552. When the threshold force is reached, the vertical extension 558 of the snap collar 552 flexes outward to separate the annular inner lip 560 of the snap collar 552 from the annular flange 524 of the post 556 of the anvil head 540.

[0165] Because the annular inner lip 560 of the snap ring 552 does not overlap and engage the annular flange 524 of the column 556 of the anvil head 540, the distal force applied by the annular knife drives the ring assembly 550 distally, whereby the support member 576 contacts the inner surface 572 of the anvil head 540 and the annular inner lip 560 of the snap ring 552 is received in the recess 526 of the column 556 of the anvil head 540, as shown in FIG. Fig.40 Continued advancement of the annular knife causes the annular knife to pierce the cutting ring 578 and eventually bottom out against the ring body 580 of the support member 576.

[0166] In an embodiment, the cutting ring 578 and the snap collar 552 can be configured such that the annular knife cuts through the cutting ring 578 before the snap collar 552 moves out of engagement with the annular flange 524 of the post 556 of the anvil head 554 .

[0167] As the ring assembly 550 advances toward the distal position, the inwardly extending fingers 598 of the support member 576 disengage from the arms of the anvil center rod, allowing the anvil head 540 to pivot relative to the anvil center rod. It is contemplated that the anvil head 540 may be configured to automatically pivot relative to the anvil center rod in any manner described herein. In an embodiment, the anvil head 540 may pivot by any suitable pivot mechanism, whether automatic or manual.

[0168] Reference Figures 41 to 44 , another embodiment of a surgical anvil assembly 626 similar to the anvil assemblies described above is shown. Due to the similarity between the anvil assembly 626 of this embodiment and the anvil assemblies described above, only those elements of the anvil assembly 626 deemed necessary to clarify the differences from the anvil assemblies described above will be described in detail.

[0169] The anvil assembly 626 includes an anvil center rod 638 and an anvil head 640 pivotally mounted to the anvil center rod 638. The anvil head 640 is adapted to Fig.41 The first operating state shown and Fig.44The anvil head 640 includes a housing 654 having a post 656 and an anvil tissue contacting surface 658. The post 656 may include a pair of spaced apart post arms defining a transverse aperture 664 extending through the spaced apart post arms. The anvil center rod 638 is at least partially positioned around the post 656 and is coupled to the anvil head 640 via a pivot member 666.

[0170] The anvil center rod 638 may include a pair of distal spacer arms 642 defining a pair of diametrically opposed longitudinally extending slots 662. The distal spacer arms 642 include distal ends through which transverse holes 644 are defined for receiving pivot members 666 that pivotally couple the posts 656 of the anvil head 640 to the distal spacer arms 642 of the anvil center rod 638. The pivot members 666 are coupled to the first position "L1" of the posts 656 of the anvil head 640 and are aligned with the central longitudinal axis "X" defined by the anvil center rod 638.

[0171] The anvil assembly 626 further includes a pivot assembly 600 that replaces a conventional plunger and cam latch assembly for driving the tilting of the anvil head 640. The pivot assembly 600 is at least partially housed within the anvil center rod 638, for example, between the spacer arms 642, and is spring biased in the proximal direction by a biasing member 602 (e.g., a coil spring). The pivot assembly 600 includes a linkage arm 604 that is received in one of the slots 662 of the distal spacer arms 642 of the anvil center rod 638. The linkage arm 604 has an L-shaped configuration and includes an elongated shaft 606 and a foot or flange 608 extending vertically from the proximal end 606a of the shaft 606. In an embodiment, the linkage arm 604 may be in any suitable shape, such as linear, curved, etc. The foot 608 of the linkage arm 604 has a pawl or post 610 extending distally therefrom for supporting the biasing member 602 of the pivot assembly 600.

[0172] The shaft 606 of the linkage arm 604 is disposed offset from the central longitudinal axis "X" of the anvil center rod 638. The shaft 606 has a distal end 606b, which is pivotally connected to the second position "L2" of the column 656 of the anvil head 640 via a pivot member 612 (e.g., a pin). The second position "L2" of the column 656 of the anvil head 640 to which the shaft 606 is pivotally connected is distal to and laterally offset from the first position "L1" of the column 656 of the anvil head 640 to which the anvil center rod 638 is pivotally connected. In this way, the longitudinal translation of the shaft 606 in the proximal or distal direction realizes the pivoting of the anvil head 640 about the first position "L1" in a counterclockwise or clockwise direction, respectively.

[0173] The biasing member 602 of the pivot assembly 600 is disposed within the anvil center rod 638 and aligned with the central longitudinal axis "X" of the anvil center rod 638 and the first position "L1". The biasing member 602 defines a hole 614 therethrough, which receives the pawl 610 of the foot 608 of the linkage arm 604 to support the biasing member 602. The biasing member 602 is inserted between the foot 608 of the linkage arm 604 and the column 656 of the anvil head 640 while being in a compressed state. In this way, the compressed biasing member 602 exerts a proximal force on the foot 608 of the linkage arm 604, which is transmitted to the second position "L2" of the column 656 of the anvil head 640. Therefore, as will be described, when the anvil head 640 is unlocked from the anvil center rod 638, the biasing member 602 drives or pulls the anvil head 640 toward the second inclined state.

[0174] The anvil assembly 626 may further include a support member (not shown) and a cutting ring (not shown) similar to the support member and cutting ring described above. Figure 3 and Figure 6 )During advancement, the support member moves within a groove 670 defined in the housing 658 of the anvil head 640.

[0175] In operation, prior to firing a circular stapling instrument having a surgical anvil assembly 626 of the presently described embodiment, the buttress member is in its retracted or proximal position in the recess 670 of the anvil head 640. With the buttress member in the proximal position, the buttress member is engaged by the spacer arms 642 of the anvil center rod 638 such that the anvil head 640 is maintained in the first operating state and is prevented from pivoting despite the proximal force applied to the anvil head 640 by the biasing member 602 via the linkage arm 604.

[0176] When the stapling instrument is actuated, the annular knife advances to engage with the cutting ring, which transmits a distal force to the support member, as described in the previous embodiment. When the support member advances to the distal position, the support member disengages from the arm 642 of the anvil center rod 638, unlocking the anvil head 640 from the anvil center rod 638. When the anvil head 640 is unlocked from the anvil center rod 638, for example, the anvil head 640 is free to pivot, and the biasing member 602 of the pivot assembly 600 drives the linkage arm 604 in the proximal direction, thereby the linkage arm 604 moves relative to the anvil center rod 638. Fig.44 The anvil head 640 is pivoted counterclockwise as indicated by the middle arrow "B". After the anvil head 640 is pivoted to the second inclined state, the anvil head 640 covers the linkage arm 604, preventing the linkage arm 604 from being caught on tissue during the removal of the surgical anvil assembly 626 from the surgical site.

[0177] During some operations, anvil head 640 can be manually pivoted back to the first operating state against the spring bias of biasing member 602. In this case, when anvil head 640 is pivoted back to the first operating state, linkage arm 604 is driven or pulled in the distal direction, and biasing member 602 is compressed between foot 608 of linkage arm 604 and post 656 of anvil head 640, resetting pivot assembly 600.

[0178] Reference Figures 45 to 48 , another embodiment of a surgical anvil assembly 726 similar to the anvil assembly described above is shown. Due to the similarity between the anvil assembly 726 of this embodiment and the anvil assembly described above, only those elements of the anvil assembly 726 deemed necessary to clarify the differences from the anvil assembly described above will be described in detail.

[0179] The anvil assembly 726 includes an anvil center rod 738 and an anvil head 740 pivotably mounted to the anvil center rod 738. The anvil head 740 is adapted to pivot between a first operating state and a second pivot or tilted state. The anvil center rod 738 may include a pair of distal spacer arms 742 for intercepting the 756 column of the anvil head 740 therebetween. As will be described, the distal spacer arms 742 of the anvil center rod 738 define a transverse hole 744 therethrough for receiving a pivot member 766.

[0180] The anvil head 740 includes a housing 754 defining a recess 770 therein, and a post 756 is centrally disposed within and extends proximally therefrom. The post 756 includes a pair of spaced apart post arms 760 defining a slot 762, the slot 762 being sized to capture the cam latch 750 therein. The spaced apart post arms 760 define a transverse hole 764 therethrough, the transverse hole 764 being sized to receive a pivot member 766. The anvil center rod 738 is at least partially positioned around the post 756 and is coupled to the anvil head 740 by a pivot member 766 extending through the distal spaced apart arms 742 of the anvil center rod 738 and the corresponding transverse holes 744, 764 of the spaced apart post arms 760 of the post 756 to pivotally couple the anvil head 740 to the anvil center rod 738.

[0181] Reference Fig.45 and 46The cam latch 750 is received in a slot 762 defined between the spaced apart post arms 760 of the post 756 and is coupled to the anvil center rod 738 and the post 756 via a pivot member 766. The cam latch 750 defines a hole or pin opening 752 through which the pivot member 766 extends. The pin opening 752 in the cam latch 750 is defined by an annular inner surface 753 of the cam latch 750. The cam latch 750 has a proximally positioned edge 757 engaged to the plunger 746 for driving rotation of the cam latch 750. The cam latch 750 is rotationally fixed in the slot 762 of the post 756 of the anvil head 740 so that when the cam latch 750 is rotated, the anvil head 740 rotates with the cam latch 750 relative to the anvil center rod 738 due to the spring bias of the plunger 746.

[0182] As briefly mentioned above, the pivot member 766 extends through the transverse hole 744 of the distal spaced arm 742 of the anvil center rod 738, the transverse hole 764 of the spaced apart post arm 760 of the post 756, and the pin opening 752 of the cam latch 750 to allow the anvil head 740 to pivot or rotate relative to the anvil center rod 738. The pivot member 766 extends through the holes 744, 764 and the pin opening 752 in a sliding fit to facilitate assembly.

[0183] The pivot member 766 is an elongated pin-like structure having opposing first and second ends 766a, 766b and a middle portion 766c disposed therebetween. It is contemplated that the first and second ends 766a, 766b and the middle portion 766c of the pivot member 766 may be integrally formed. An annular groove 780 is formed in an outer surface 782 of the pivot member 766. The annular groove 780 is disposed along the middle portion 766c of the pivot member 766. Thus, the first and second ends 766a, 766b of the pivot member 766 have a first diameter, and the middle portion 766c of the pivot member 766 has a second diameter that is smaller than the first diameter.

[0184] The slot 780 in the pivot member 766 may be cylindrical and extend circumferentially around the middle portion 766c of the pivot member 766. As such, the slot 780 has step portions 784a, 784b on opposite sides thereof to limit lateral movement of the pivot member 766 within and relative to the pin opening 752 of the cam latch 750. The diameter of the middle portion 766c is smaller than the diameter of the pin opening 752 of the cam latch 750. This allows for a simplified sliding fit of the pivot member 766 into the pin opening 752 of the cam latch 750 during assembly.

[0185] Reference Figures 45 to 48As will be described, the inner surface 753 of the cam latch 750 has a proximal portion 755 that is received in the slot 780 of the pivot member 766 and is spring-biased into contact with the outer surface 782 of the pivot member 766 via the plunger 746. The length of the slot 780 is greater than the thickness of the cam latch 750 to allow some lateral movement of the pivot member 766 within the pin opening 752 of the cam latch 750.

[0186] The anvil assembly 726 further includes a plunger 746 and a plunger spring 748. The plunger 746 is at least partially received within the anvil center rod 738, for example, between the spacer arms 742, and is spring biased in the distal direction by the plunger spring 748. The plunger 746 includes a plunger finger 759 that engages the proximal edge 757 of the cam latch 50 to retain the proximal portion 755 of the inner surface 653 of the cam latch 750 in the groove 780 of the pivot member 766. Due to the spring bias of the plunger 746 on the cam latch 750, the proximal portion 755 of the inner surface 753 of the cam latch 750 is frictionally engaged with the outer surface 782 of the pivot member 766 to retain the pivot member 766 in the pin opening 752 of the cam latch 750.

[0187] The anvil assembly 726 further includes a support member 776 and a cutting ring 778 similar to the support member and cutting ring described above. Figure 3 and Figure 6 ), during the advancement of the anvil head 740, the support member 776 moves within the groove 770 of the anvil head 740. The support member 776 includes a pair of directly opposite fingers (not explicitly shown) extending inwardly. The fingers are engaged by the spacing arms 742 of the anvil center rod 738 to prevent the support member 776 from moving in the proximal direction and to maintain the anvil head 740 in an operative state (e.g., not tilted). Only after the fingers 798 are spaced apart distally from the arms 742 of the anvil center rod 738 is the anvil head 740 allowed to pivot relative to the anvil assembly 726, as described in the previous embodiment.

[0188] In operation, prior to firing a circular stapling instrument having a surgical anvil assembly 726 of the presently described embodiment, the buttress member 676 is in its retracted or proximal position in the recess 770 of the anvil head 740. With the buttress member 776 in the proximal position, the inwardly extending fingers of the buttress member 776 are engaged by the spacer arms 742 of the anvil center rod 738 such that the anvil head 740 is maintained in the first operating state and is prevented from pivoting despite distal forces exerted on the anvil head 740 by the plunger 746 via the cam latch 750.

[0189] When the stapling instrument is actuated, the annular knife 30 is advanced to engage with the cutting ring 778, which transmits a distal force to the support member 776. When the support member 776 is advanced toward the distal position, the inwardly extending fingers of the support member 776 disengage from the arms 742 of the anvil center rod 738, unlocking the anvil head 740 from the anvil center rod 738. As the anvil head 740 is unlocked from the anvil center rod 738 (e.g., the anvil head 740 is free to pivot), the spring-biased plunger 746 drives the cam latch 750 to rotate about the pivot member 766. Since the cam latch 750 is rotationally fixed within the anvil head 740, the anvil head 740 is caused to rotate about the pivot member 766 relative to the anvil center rod 738. In an embodiment, the pivot member 766 can rotate with the anvil head 740.

[0190] Reference Figures 49 to 52 , another embodiment of a surgical anvil assembly 826 similar to the anvil assembly described above is shown. Due to the similarity between the anvil assembly 826 of this embodiment and the anvil assemblies described above, only those elements of the anvil assembly 826 deemed necessary to clarify the differences from the anvil assemblies described above will be described in detail.

[0191] The anvil assembly 826 includes an anvil center rod 838 and an anvil head 840 pivotally mounted to the anvil center rod 838. The anvil head 840 is adapted to pivot between a first operative state and a second pivoted or tilted state ( Fig.49 and 52 ). The anvil center rod 838 may include a pair of distal spaced arms 842 for intercepting the post 856 of the anvil head 840 therebetween. The distal spaced arms 842 of the anvil center rod 838 define a transverse hole therethrough for receiving the pivot member 866.

[0192] The anvil head 840 defines a recess 870 therein. The post 856 is centrally disposed within the recess 870 and extends proximally therefrom. The post 856 includes a pair of spaced apart post arms 860 defining a slot 862, the slot 862 being sized to capture the cam latch 850 therein. The spaced apart post arms 860 define a transverse hole 864 therethrough, the transverse hole 864 being sized to receive a pivot member 866. The anvil center rod 838 is at least partially positioned about the post 856 and is coupled to the anvil head 840 by a pivot member 866 extending through the distal spaced apart arms 842 of the anvil center rod 838 and the corresponding transverse holes of the spaced apart post arms 860 of the post 856 to pivotally couple the anvil head 840 to the anvil center rod 838. The post 856 further includes a pair of flanges 880 projecting proximally from the corresponding pair of post arms 860. The flanges 880 each have a vertical surface 882 that projects perpendicularly from the circular surface 884 of the corresponding post arm 860 .

[0193] The cam latch 850 is received between the spaced apart post arms 860 and between the flanges 880 of the post 856. The cam latch 850 is coupled to the anvil center rod 838 and the post 856 via a pivot member 866 that extends through a hole or pin opening 868 of the cam latch 50. Fig.51 As shown, the cam latch 850 has an outer peripheral surface 852, which includes a cam area 852a and a notch area 852b adjacent to the cam area 852a. The cam area 852a can have an arcuate shape and is configured to engage with the plunger 846 ( Fig.52 ) engages, the plunger 846 drives the rotation of the cam latch 850.

[0194] The notched region 852b of the cam latch 850 has a profile that matches the profile defined by the vertical surface 882 of the flange 880 and the circular surface 884 of the spaced-apart post arm 860. The notched region 852b includes a stop surface 854 that extends generally radially inward from the end of the cam region 852b. The stop surface 854 is configured to engage the plunger finger 857 of the plunger 846 when the anvil head 840 enters the second title state, as shown in FIG. Fig.49 and 52 The cam latch 850 is rotationally fixed within the slot 862 of the post 856 of the anvil head 840 so that when the cam latch 850 is rotated, the anvil head 840 rotates with the cam latch 850 relative to the anvil center rod 838 due to the spring bias of the plunger 846.

[0195] The anvil assembly 826 further includes a plunger 846 and a plunger spring 848. The plunger 846 is at least partially received within the anvil center rod 838, e.g., between the spacer arms 842, and is spring biased in the distal direction by the plunger spring 848. The plunger spring 848 has a spring constant that is sufficiently high to prevent manual compression of the plunger spring 848. Thus, manual pivoting of the anvil head 840 from the tilted state back toward the untilted state is resisted by the plunger spring 848.

[0196] The plunger 846 includes a plunger finger 857 at its distal end, which engages the cam region 852a of the cam latch 850 to bias the cam latch 850 and thereby the anvil head 840 toward the second inclined state. When the anvil head 840 is free to pivot relative to the anvil center rod 838, the plunger finger 857 pushes the cam region 852a of the cam latch 850, whereby the cam region 852a of the cam latch 850 rides along the plunger finger 857, rotating the anvil head 840. When the anvil head 840 enters the second inclined state, the notch region 852b of the cam latch 850 passes over the plunger finger 857, whereby the stop surface 854 of the cam latch 850 is positioned to contact the plunger finger 857. Rotation of the cam latch 850 in the opposite direction (eg, rotation of the anvil head 840 away from the first operating state) is resisted by the plunger 846 and the plunger spring 848 due to contact between the stop surface 854 of the cam latch 850 and the plunger finger 857 .

[0197] The anvil assembly 826 further includes a support member 876 and a cutting ring 878 similar to the support member and cutting ring described above. Figure 3 and Figure 6 ), during the advancement of the anvil head 840, the support member 876 moves in the groove 870 of the anvil head 840. The support member 876 includes a pair of inwardly extending diametrically opposed fingers 898. The fingers 898 are engaged by the spacer arms 842 of the anvil center rod 838 to prevent the support member 876 from moving in the proximal direction and to maintain the anvil head 840 in an operative state (e.g., not tilted). Only after the fingers 898 are spaced apart from the arms 842 of the anvil center rod 838 in the distal direction, the anvil head 840 is allowed to pivot relative to the anvil assembly 826.

[0198] In operation, prior to firing a circular stapling instrument having a surgical anvil assembly 826 of the presently described embodiment, the buttress member 876 is in its retracted or proximal position in the recess 870 of the anvil head 840. With the buttress member 876 in the proximal position, the inwardly extending fingers 898 of the buttress member 876 are engaged by the spacer arms 842 of the anvil center rod 838, such that the anvil head 840 is maintained in the first operating state and is prevented from pivoting despite distal forces exerted on the anvil head 840 by the plunger 846 via the cam latch 850.

[0199] When the stapling instrument is actuated, the annular knife 30 is advanced to engage with the cutting ring 878, which transmits a distal force to the support member 876. When the support member 876 advances to the distal position, the inwardly extending finger-shaped member 898 of the support member 876 disengages from the arm 842 of the anvil center rod 838, unlocking the anvil head 840 from the anvil center rod 838, as described in detail above. As the anvil head 840 is unlocked from the anvil center rod 838 (e.g., the anvil head 840 is free to pivot), the spring-biased plunger 846 drives the rotation of the cam latch 850. Since the cam latch 850 is rotationally fixed in the anvil head 840, the anvil head 840 is rotated relative to the anvil center rod 838.

[0200] When the anvil head 840 is rotated to the second tilted state, the plunger 846 is received in the notch area 852b of the cam latch 850, whereby the stop surface 854 of the notch area 852b of the cam latch 850 overlaps the plunger finger 857. In this way, attempts to rotate the anvil head 840 away from the first operating state will be resisted by the distal force exerted on the notch area 852b of the cam latch 850 by the spring biased plunger 846. As described above, the biasing member 848 has a spring constant that is high enough to resist manual attempts to reset the anvil head 840.

[0201] Reference Figures 53 to 55 , another embodiment of a surgical anvil assembly 926 similar to the anvil assemblies described above is shown. Due to the similarity between the anvil assembly 926 of this embodiment and the anvil assemblies described above, only those elements of the anvil assembly 926 deemed necessary to clarify the differences from the anvil assemblies described above will be described in detail.

[0202] The anvil assembly 926 generally includes an anvil center rod (not shown) similar to the anvil center rod described above, an anvil head 940 pivotally mounted to the anvil center rod, and a ring assembly 950 configured to selectively unlock the anvil head 940 from the anvil center rod. The anvil head 940 is configured to pivot relative to the anvil center rod between a first operating state and a second pivoted or tilted state.

[0203] The anvil head 940 includes an inner surface 972 defining a recess 970 therein, the recess 970 being sized to receive the ring assembly 950. The inner surface 972 has an outer periphery 973 defining an annular groove 975 therein. The groove 975 extends radially outward from the recess 970 and communicates with the recess 970. The groove 975 is disposed adjacent to the tissue contacting surface 958 of the anvil head 940 and extends circumferentially around the outer periphery 973 of the inner surface 972 of the anvil head 940. The height of the groove 975 is defined between a proximal flange 975a and a distal flange 975b thereof.

[0204] The ring assembly 940 includes a support member 976 and a cutting ring 978 similar to the support member 476 described above. The support member 976 is received in the groove 970 of the anvil head 940, and the cutting ring 978 is nested in the support member 976. The cutting ring includes an annular inner body portion 978a and an annular outer body portion 978b, which is integrally formed with the inner body portion 978a and is circumferentially arranged around the inner body portion 978a. The inner body portion 978a and the outer body portion 978b can be formed by a single piece of polytetrafluoroethylene, polypropylene or polyester. Other materials are expected. In some embodiments, the outer body portion 978b can be a separate piece attached to the inner body portion 978a.

[0205] The inner body portion 978a of the cutting ring 978 is supported on the support member 976 and disposed in the groove 970 of the anvil head 940, and the outer body portion 978b of the cutting ring 978 is captured between the proximal and distal flanges 975a, 975b of the groove 975 of the anvil head 940. The diameter of the cutting ring 978 is greater than the diameter of the groove 970 of the anvil head 940 so that the cutting ring 978 can be press-fit into the groove 970 during assembly. Once assembled, the outer body portion 978b of the cutting ring 978 extends radially beyond the support member 976. Because the outer body portion 978b of the cutting ring 978 overlaps the proximal and distal flanges 975a, 975b, both proximal and distal movement of the outer body portion 978b of the cutting ring 978 away from the groove 975 is resisted. As will be described, the outer body portion 978b of the cutting ring 978 can have a reduced thickness relative to the inner body portion 978a to allow some play of the outer body portion 978b of the cutting ring 978 within the groove 975. In an embodiment, the height of the inner body portion 978a of the cutting ring 978 can be substantially similar or the same as the height of the groove 975.

[0206] In operation, prior to firing a circular stapling instrument having a surgical anvil assembly 926 of the presently described embodiment, the ring assembly 950 including the support member 976 and the cutting ring 978 is in its retracted or proximal position. A frangible retainer member (not explicitly shown) is inserted between the support member 976 and the inner surface 972 of the anvil head 940 to support the ring assembly 950 in the proximal position, as shown in FIG. Fig.53 With the ring assembly 950 in the proximal position, the support member 976 engages the anvil center rod such that the anvil head 940 remains in the first operative state.

[0207] When the stapling instrument is actuated, the annular knife (e.g. Figure 6Annular knife 30 (shown in FIG. 1 ) is advanced to engage with cutting ring 978 and cuts or shears outer body portion 978b of cutting ring 978 from inner body portion 978a of cutting ring 978. When cutting through cutting ring 978, annular knife 30 engages support member 976, thereby driving support member 976 toward a distal position.

[0208] Since the inner body portion 978a of the cutting ring 978 is held by the support member 976, the inner body portion 978a moves toward the distal position together with the support member 976. The outer body portion 978b of the cutting ring 978 is captured between the outer periphery 973 of the inner surface 972 of the anvil head 940 and the outer surface of the annular knife 30. Fig.54 As shown, the outer body portion 978b of the cutting ring 978 is retained in the groove 975 when the inner body portion 978a of the cutting ring 978 is advanced distally.

[0209] As the ring assembly 950 advances toward the distal position, the support member 976 disengages from the anvil center rod, allowing the anvil head 940 to pivot relative to the anvil center rod. It is contemplated that the anvil head 940 may be configured to automatically pivot relative to the anvil center rod in any manner described herein. In an embodiment, the anvil head 940 may pivot by any suitable pivot mechanism, whether automatic or manual.

[0210] Reference Fig.55 , the retraction of the annular knife 30 to its starting position causes the outer body portion 978b of the cutting ring 978 to move proximally within the groove 975 due to the frictional engagement between the outer surface of the annular knife 30 and the inner peripheral surface 979 of the outer body portion 978b of the cutting ring 978. The outer body portion 978b of the cutting ring 978 is dragged proximally by the retracted annular knife 30 until the outer body portion 978b of the cutting ring 978 contacts the proximal flange 975a. With the outer body portion 978b of the cutting ring 978 in contact with the proximal flange 975a, the outer body portion 975b and the inner body portion 978a are axially spaced apart from each other, thereby forming a channel 982 through which the staples embedded in the cutting ring 978 can be removed.

[0211] Those skilled in the art will appreciate that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is conceivable that the elements and features illustrated or described in conjunction with one exemplary embodiment may be combined with the elements and features of another exemplary embodiment without departing from the scope of the present disclosure. Similarly, those skilled in the art will understand other features and advantages of the present disclosure based on the above-described embodiments. Therefore, except as indicated by the appended claims, the present disclosure is not limited by what has been specifically illustrated and described.

Claims

1. A surgical anvil assembly for use with a circular stapling instrument, comprising: anvil center rod; an anvil head pivotally coupled to the anvil center rod and movable between a first operating condition and a second inclined condition; as well as a ring assembly disposed within a recess of the anvil head and movable within the recess from a proximal position preventing pivotal movement of the anvil head away from the first operating condition to a distal position permitting pivotal movement of the anvil head to the second inclined condition, wherein the ring assembly comprises: a support member configured to engage the anvil center rod when the ring assembly is in the proximal position; an annular cup nested with the support member and defining an annular chamber, the annular cup having an outer wall defining a chamfered surface; as well as A cutting ring is disposed in the annular chamber, wherein the cutting ring is made of a material softer than the annular cup, so that when the annular knife is advanced, the annular knife is guided toward the cutting ring by the chamfered surface to pierce the cutting ring.

2. The surgical anvil assembly of claim 1, wherein the chamfered surface extends radially inward from the outer wall and defines an undercut, an outer edge of the cutting ring being disposed below the undercut.

3. The surgical anvil assembly of claim 2, wherein the chamfered surface has an annular inner edge and the outer wall has an annular inner peripheral surface disposed radially outward of the annular inner edge.

4. The surgical anvil assembly of claim 2, wherein the chamfered surface slopes downwardly from a proximal surface of the outer wall.

5. The surgical anvil assembly of claim 1 , wherein the annular cup further comprises: a first inner wall; and A base is interconnected with the outer wall and the first inner wall, the outer wall, the first inner wall and the base cooperatively defining the annular chamber.

6. The surgical anvil assembly of claim 5, wherein the annular cup further comprises a second inner wall disposed radially inwardly of the first inner wall, the second inner wall and the support member being engaged with each other.

7. The surgical anvil assembly of claim 6, wherein the support member comprises: an annular wall engaged to the second inner wall of the annular cup; and A platform extends radially outward from a distal portion of the annular wall, the platform supporting the base of the annular cup thereon.

8. The surgical anvil assembly of claim 1, wherein the annular cup is captured between the support member and an annular inner peripheral surface of the anvil head.

9. The surgical anvil assembly of claim 1, wherein the outer wall of the annular cup is configured to flex radially inwardly upon distal advancement thereof into the recess of the anvil head.

10. The surgical anvil assembly of claim 9, wherein the outer wall of the annular cup has a plurality of slits defined therein, the plurality of slits being disposed circumferentially about the outer wall.

11. The surgical anvil assembly of claim 9, wherein the outer wall of the annular cup has an outer lip extending radially outward therefrom, the outer lip overlapping an inner ring extending radially inward from the annular inner peripheral surface of the anvil head.

12. The surgical anvil assembly of claim 1, wherein the cutting ring is overmolded to the annular cup and extends through a plurality of apertures defined by the annular cup.

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