Pivoting anvil for surgical circular stapler

1. A circular stapler apparatus for stapling tissue, comprising:

(a) a stapling head assembly; and

(b) an anvil configured to form staples advanced by the stapling head assembly, the anvil comprising:

(i) an anvil head having a proximal face,

(ii) a shaft extending along a central shaft axis between a distal shaft end that couples to the anvil head and a proximal shaft end that freely terminates and is configured to releasably couple with the stapling head assembly,

(iii) a first pivot defining a first pivot axis,

(iv) a second pivot spaced axially from the first pivot along the central shaft axis and defining a second pivot axis, and

(v) a driver member movably disposed within the shaft;

wherein the anvil head is configured to pivot about the first and second pivot axes between a first position and a tilted second position, wherein in the first position the proximal face of the anvil head extends perpendicularly to the central shaft axis, and in the tilted second position the proximal face extends obliquely to the central shaft axis to define a distally opening acute angle therebetween, wherein a vertex of the acute angle is located proximally of the first pivot,

wherein in the first position the first and second pivots are located on the central shaft axis,

wherein in the tilted second position the first pivot is radially offset from the central shaft axis,

wherein the driver member is operable to urge the anvil head toward the tilted second position.

2. The circular stapler apparatus of claim 1 , wherein the vertex of the acute angle is located distally of the proximal shaft end.

3. The circular stapler apparatus of claim 1 , wherein the anvil head further includes a proximally extending connector that pivotably couples the anvil head to the distal shaft end.

4. The circular stapler apparatus of claim 1 , wherein the driver member is translatable along the central shaft axis.

5. The circular stapler apparatus of claim 4 , wherein the driver member is translatable between a retracted position in which the driver member permits the anvil head to move to the first position, and a deployed position in which the driver member urges the anvil head toward the tilted second position.

6. The circular stapler apparatus of claim 5 , wherein the driver member is arranged to directly contact the proximal face of the anvil head when the driver member is in the deployed position.

7. The circular stapler apparatus of claim 5 , wherein the driver member is configured to extend distally beyond the distal shaft end in the deployed position.

8. The circular stapler apparatus of claim 6 , wherein the driver member in the deployed position is configured to directly contact a portion of the proximal face of the anvil head that is offset in a radial direction from the central shaft axis.

9. The circular stapler apparatus of claim 1 , wherein the driver member includes a rod that extends coaxially with the central shaft axis.

10. The circular stapler apparatus of claim 1 , wherein the shaft includes a first shaft portion and a second shaft portion coupled to the first shaft portion, wherein the first shaft portion is pivotably coupled to the anvil head with the first pivot to provide the anvil head with a first degree of movement relative to the central shaft axis, and the first shaft portion is movable relative to the second shaft portion to provide the anvil head with a second degree of movement relative to the central shaft axis.

11. The circular stapler apparatus of claim 10 , wherein the second pivot couples the first shaft portion to the second shaft portion, wherein the second pivot is located proximally of the first pivot and is configured to enable the first shaft portion to pivot relative to second shaft portion.

12. The circular stapler apparatus of claim 11 , wherein the first and second shaft portions are configured to align coaxially when the anvil head is in the first position such that the first pivot, the second pivot, and the proximal shaft end are arranged collinearly.

13. The circular stapler apparatus of claim 11 , wherein the anvil head is configured to pivot about the first pivot axis relative to the first shaft portion in a first pivoting direction, and the first shaft portion is configured to pivot about the second pivot axis relative to the second shaft portion in a second pivoting direction that is opposite the first pivoting direction.

14. The circular stapler apparatus of claim 1 , wherein the second pivot is fixed in a radial direction relative to the central shaft axis.

15. A circular stapler apparatus for stapling tissue, comprising:

(a) a stapling head assembly; and

(b) an anvil configured to form staples advanced by the stapling head assembly, the anvil comprising:

(i) an anvil head,

(ii) a shaft extending proximally from the anvil head and having a distal shaft portion and a proximal shaft portion,

(iii) a first pivot coupling the anvil head to the distal shaft portion and defining a first pivot axis,

(iv) a second pivot coupling the distal shaft portion to the proximal shaft portion and defining a second pivot axis, and

(v) a driver member movably disposed within the shaft;

wherein the anvil head is configured to pivot relative to the distal shaft portion about the first pivot axis in a first pivot direction from a first anvil head position to a second anvil head position, and the distal shaft portion is configured to pivot relative to the proximal shaft portion about the second pivot axis in a second pivot direction different than the first pivot direction from a first distal shaft position to a second distal shaft position,

wherein the distal shaft portion is configured to assume the second distal shaft position while the anvil head is in the second anvil head position,

wherein the driver member is movable relative to the shaft to urge the anvil head toward the second anvil head position.

16. The circular stapler apparatus of claim 15 , wherein the first and second pivots are arranged along a longitudinal axis that extends parallel to a longitudinal axis defined by the distal shaft portion.

17. The circular stapler apparatus of claim 15 , wherein the proximal shaft portion includes an opening configured to receive a trocar of the circular stapler apparatus.

18. A circular stapler apparatus for stapling tissue, comprising:

(a) a stapling head assembly; and

(b) an anvil configured to form staples advanced by the stapling head assembly, wherein the anvil comprises:

(i) a shaft having a proximal shaft portion defining a proximal shaft axis and a distal shaft portion pivotably coupled thereto and defining a distal shaft axis,

(ii) an anvil head pivotably coupled with the distal shaft portion, wherein the anvil head includes a proximal face and is moveable relative to the proximal shaft portion between a first anvil position and a second anvil position, and

(iii) a translatable member,

wherein in the first anvil position the proximal and distal shaft axes are arranged coaxially and the proximal face extends perpendicularly thereto,

wherein in the second anvil position the proximal and distal shaft axes are arranged angularly and the proximal face extends obliquely to the proximal shaft axis,

wherein the translatable member is movable distally within the distal shaft portion to urge the anvil head toward the second anvil position.

19. The circular stapler apparatus of claim 18 , wherein the proximal shaft portion is configured to align coaxially with the stapling head assembly in both the first anvil position and the second anvil position.

20. The circular stapler apparatus of claim 18 , wherein the distal shaft axis comprises a central distal shaft axis, wherein the translatable member is movably disposed within the distal shaft portion and along the central distal shaft axis.