Endoscopic microsurgical instruments

Microsurgical instruments for performing extremely small-scale, minimally-invasive microsurgery such as thoracoscopic coronary artery bypass grafting. The instruments utilize a symmetrical, forcep-like actuator which provides extremely precise actuation and control of the instrument and which mimics the feel of instruments used in conventional open surgical procedures. The instruments generally include a pair of coaxially arranged shafts, an end-effector at the distal ends of the shafts, and an actuator at the proximal ends of the shafts. The actuator includes a pair of arms pivotally coupled to one of the outer and inner shafts, and a pair of links pivotally coupled at one end to the arms, and at a second end to the other of the shafts. The links are coupled to a proximal portion of the arms to maximize mechanical advantage and reduce interference. The actuator may be easily adapted for either pull-type or push-type actuation, and for either outer shaft or inner shaft translation. The actuator is provided with a locking mechanism for fixing the relative position of the shafts to maintain the end-effector in a closed position. The locking mechanism includes rigid catches that are engaged upon actuation of the actuator and are disengaged upon further actuation of the actuator. The end-effectors may have a variety of configurations, including needle drivers, forceps, scissors, and clip appliers.

What is claimed is:

1. A surgical instrument comprising:

a first shaft;

a second shaft disposed adjacent the first shaft, the first and second shafts being movable relative to each other;

an actuator coupled to the first and second shafts for imparting relative movement thereto; and

a locking mechanism provided on the actuator for locking the first and second shafts in a desired relative position, the locking mechanism including first and second catches configured to engage and disengage each other upon actuation of the actuator, the first and second catches being attached to the actuator by connections which permit each catch to move with respect to the actuator, wherein each connection is disposed adjacent one of the catches and lies along a line that passes generally through the first and second catches when engaged.

2. The surgical instrument of claim 1, wherein each of the first and second catches is attached to the actuator by a pivoted connection.

3. The surgical instrument of claim 2, wherein each of the first and second catches is spring-biased to a desired position with respect to the actuator.

4. The surgical instrument of claim 3, wherein the pivoted connection for each of the first and second catches includes a pivot pin supporting a spring which biases the catch to the desired position.

5. The surgical instrument of claim 3, wherein one of the first and second catches is biased to an angled position relative to the other catch when the catches are disengaged but lies generally along the line passing through the connections when the catches are engaged.

6. The surgical instrument of claim 1, wherein one of the first and second catches includes a recess that receives a tapered head provided on the other of the catches.

7. The surgical instrument of claim 6, wherein the recess has an undercut portion to prevent the tapered head from sliding out of the recess.

8. The surgical instrument of claim 1, wherein the first and second catches are attached to the actuator by pivoted connections and further comprising a pair of springs respectively secured to each catch and the actuator to bias each catch about the pivoted connections to a desired position.

9. The surgical instrument of claim 1, wherein actuation of the actuator moves the first and second catches toward each other causing the first catch to pivot in a first direction into locking engagement with the second catch, and further actuation of the actuator moves the first and second catches closer together causing the catches to disengage.

10. The surgical instrument of claim 1, wherein the actuator includes an actuator body and first and second arms pivotally attached to the actuator body for movement toward and away from each other between closed and open positions, the first and second arms respectively carrying the first and second catches.

11. The surgical instrument of claim 10, wherein the actuator body is attached to one of the first and second shafts and the first and second arms are coupled to the other of the shafts, wherein movement of the first and second arms between said open and closed positions imparts relative movement to the first and second shafts.

12. The surgical instrument of claim 11, wherein the first and second arms are coupled to the other of the first and second shafts by a pair of pivotally mounted links.

13. The surgical instrument of claim 12, wherein the arms have proximal ends and distal ends and the pivotally mounted links are disposed closer to the proximal ends than the distal ends of the arms.

14. The surgical instrument of claim 1, wherein the first and second catches are formed of a rigid material.

15. The surgical instrument of claim 1, wherein the first and second shafts comprises inner and outer coaxial shafts, and the inner shaft moves with respect to the outer shaft.

16. A surgical instrument actuator comprising:

a first member;

a second member disposed adjacent the first member, the first and second members being relatively movable and configured for attachment to an instrument end-effector;

two relatively movable components configured to be actuated by a user to impart relative movement to the first and second members; and

a locking mechanism operable by actuation of the two relatively movable components and including first and second catches configured to engage each other to lock the first and second members in a desired relative position, the first and second catches respectively attached to the two relatively movable components by connections which permit each catch to move with respect to the component, wherein the first catch moves relative to one movable component along a surface of the second catch to lock the first and second members in a desired relative position, and the second catch moves relative to the other component and the first catch moves along an opposite surface of the second catch to release the first and second members from said desired relative position.

17. The surgical instrument actuator of claim 16, wherein the two relatively movable components are two arms hinged to an actuator body, and the first and second catches are respectively attached to the two arms by pivoted connections.

18. The surgical instrument actuator of claim 17, wherein the first and second members are two coaxial shafts.

19. A surgical instrument comprising:

first and second relatively movable shafts;

an end-effector coupled to the first and second shafts so as to move in response to relative movement of the shafts;

an actuator coupled to the first and second shafts and including two arms movable toward and away from each other for imparting relative movement to the first and second shafts; and

a locking mechanism for locking the first and second shafts in a desired relative position, the locking mechanism including cooperating catches each secured to one of the two arms of the actuator by a pivoted connection so as to be movable relative thereto, wherein moving the arms toward each other to a first position locks the catches together to fix the first and second shafts in a desired relative position, and moving the arms further toward each other from the first position unlocks the catches to release the first and second shafts from said desired relative position.

20. The surgical instrument of claim 19, wherein the first and second shafts are coaxial and the inner shaft moves with respect to the outer shaft.