Multiple firing stroke surgical instrument incorporating electroactive polymer anti-backup mechanism

• US 20060060630A1
• Filed: 07/14/2005
• Published: 03/23/2006
• Est. Priority Date: 07/28/2004
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Inventors: Shelton, Frederick E. IV, Wales, Kenneth S.
• Granted Patent: US 7,513,408 B2
• Time in Patent Office: Days
• US Class Current: 227/175.200
• CPC Class Codes: A61B 17/07207 the staples being applied sequentially
• CPC Class Codes: A61B 17/2909 Handles
• CPC Class Codes: A61B 2017/00398 using powered actuators, e.g. stepper motors, solenoids
• CPC Class Codes: A61B 2017/00407 Ratchet means
• CPC Class Codes: A61B 2017/00871 polymeric

Abstract

A surgical stapling and severing instrument particularly suited to endoscopic procedures incorporates a handle that produces separate closing and firing motions to actuate an end effector. In particular, the handle produces multiple firing strokes in order to reduce the required amount of force required to fire (i.e., staple and sever) the end effector. A firing member reciprocates within an elongate shaft to the end effector to transfer this firing motion. A retraction spring retracts the firing member after full firing. Between firing strokes as the firing trigger is released, an anti-backup mechanism activates an electrical actuator (e.g., elecroactive polymer actuator) that is physically grounded to the handle to bind the firing member preventing inadvertent retraction.

Claims

1. A surgical instrument, comprising:

an end effector;

a longitudinally reciprocating firing rod distally coupled to the end effector;

a shaft having a distal end attached to the end effector and operatively configured to guide the firing rod;

a handle attached to a proximal end of the shaft operatively configured to distally advance the firing rod in a sequence of strokes; and

an electrical actuator physically grounded to the handle and responsive to an electrical signal to move between a non-binding and a binding position with the firing member to prevent longitudinal movement thereof.

2. The surgical instrument of claim 1, wherein the electrical actuator comprises an electroactive polymer actuator.

3. The surgical instrument of claim 1, wherein the electrical actuator further comprises:

a locking plate through hole encompassing the firing rod sized for nonbinding contact when in an unlocked state perpendicular to the firing rod and for binding contact when in a locked state when tipped at an angle from perpendicular, the electrical actuator positioned to move the locking plate from a selected state to the other state of a group consisting of the unlocked state and the locked state.

4. The surgical instrument of claim 3, further comprising a resilient member biasing the locking plate to the locked state with distal motion of the firing rod opposing the resilient member to move the locking plate to the unlocked state, the electrical actuator comprising an anti-backup cam tube position to selectively oppose and overcome when activating the resilient member.

5. The surgical instrument of claim 4, wherein the electrical actuator comprises electroactive polymer actuators operatively configured to expand longitudinally when activated urging the anti-backup cam tube distally from the handle.

6. The surgical instrument of claim 4, further comprising:

a proximally projecting yoke attached to the anti-backup cam tube;

a manual release mechanism operatively configured to transmit a release motion to the proximally projecting yoke to manually actuate the anti-backup cam tube to release the locking plate.

7. The surgical instrument of claim 6, further comprising a manual release control operatively configured for user actuation, the manual release mechanism operatively configured to transmit the release motion from the manual release control.

8. The surgical instrument of claim 6, further comprising an unlocking feature coupled for motion in the handle to the firing rod, an anti-backup release lever responsive to the unlocking feature moved to a distal position corresponding to full firing travel of the firing rod to urge the proximally projecting yoke distally to unlock the locking plate.

9. The surgical instrument of claim 1, wherein the electrical actuator comprises a wound spring radially encompassing the firing rod and an electrical device operatively configured to change an inner diameter of the wound spring between a selected one to the other of a group consisting of a locking state of a smaller diameter in binding contact with the firing rod and an unlocking state of a larger diameter in nonbinding contact with the firing rod.

10. The surgical instrument of claim 9, wherein the wound spring further comprises a first end held against rotation by the shaft and a radially extended end, the electrical actuator comprising an electroactive polymer actuator positioned to rotate the radially extended end to effect the selected state.

11. The surgical instrument of claim 1, wherein the shaft further comprises a frame ground longitudinally positioned by the handle, the electrical actuator comprising an electroactive polymer sleeve encompassing the firing rod and attached to the frame ground.

12. The surgical instrument of claim 11, wherein the electroactive polymer sleeve is operatively configured to have an internal diameter for binding contact when in a selected one of an energized state and an unenergized state and a larger internal diameter for nonbinding contact when in the nonselected state.

13. The surgical instrument of claim 11, wherein the electroactive polymer sleeve when in an unenergized, relaxed state has an internal diameter larger than the firing rod for nonbinding, unlocked contact and an energized state expanding a radial thickness of the electroactive polymer sleeve, wherein the shaft is operatively configured to constrain outward expansion of the electroactive polymer sleeve forcing the electroactive polymer sleeve into binding contact with the firing rod when energized.

14. The surgical instrument of claim 1, wherein the end effector comprises a staple applying assembly.

15. The surgical instrument of claim 1, further comprising:

an end effector;

a handle;

an elongate shaft comprising a frame ground attaching the end effector to the handle and a firing member guided for longitudinal reciprocating motion between the handle and the end effector;

a firing trigger attached for movement to the handle;

a multiple stroke firing mechanism in the handle operatively configured to distally advance the firing member incrementally with each firing stroke of the firing trigger;

a retraction bias urging the firing member to a retracted position; and

a means for electrically locking and unlocking the firing member for preventing inadvertent retraction of the firing member between firing strokes of the firing trigger.

16. A surgical instrument, comprising:

an end effector;

a handle;

an elongate shaft comprising a frame ground attaching the end effector to the handle and a firing member guided for longitudinal reciprocating motion between the handle and the end effector;

a firing trigger attached for movement to the handle;

a multiple stroke firing mechanism in the handle operatively configured to distally advance the firing member incrementally with each firing stroke of the firing trigger;

a retraction biasing member positioned in the handle to assert a retraction bias on the firing member;

an anti-backup mechanism comprising an electrical actuator operatively configured to move between a locking and an unlocking state with the firing member; and

control circuitry operatively configured to activate the electrical actuator.

17. The surgical instrument of claim 16, wherein the anti-backup mechanism further comprises:

a locking plate having a through hole sized to disengage from the firing rod when perpendicular and locked when angled;

a spring biasing the locking plate to a back tipped angled position;

a cam member opposing the spring; and

an electroactive polymer actuator positioned to move the cam member and the locking plate in turn to the locked state.

18. The surgical instrument of claim 16, further comprising a wound spring having a first end held against rotation by the shaft and a radially extended end, the electrical actuator comprising an electroactive polymer actuator positioned to rotate the radially extended end to effect to change an inner diameter of the wound spring to effect a change of the state selected from a group consisting of the locked state and the unlocked state.

19. The surgical instrument of claim 16, wherein the elongate shaft further comprises a frame ground longitudinally positioned by the handle, the electrical actuator comprising an electroactive polymer sleeve encompassing the firing rod and attached to the frame ground and operatively configured to have an internal diameter for binding contact when in a selected one of an energized state and an unenergized state and a larger internal diameter for nonbinding contact when in the nonselected state.

20. The surgical instrument of claim 19, wherein the electroactive polymer sleeve when in an unenergized, relaxed state has an internal diameter larger than the firing rod for nonbinding, unlocked contact and an energized state expanding a radial thickness of the electroactive polymer sleeve, wherein the frame ground is operatively configured to constrain outward expansion of the electroactive polymer sleeve forcing the electroactive polymer sleeve into binding contact with the firing rod when energized.