Stereotaxic apparatus and method for moving an end effector

What is claimed is:

1. An apparatus for use in moving an end effector, the apparatus comprising:

a first manipulator comprising a coarse motion manipulator with at least three degrees-of-freedom and a fine motion manipulator with at least three degrees-of-freedom; and

a second manipulator connected to a distal end of the first manipulator, the second manipulator having means for providing at least three orthogonally decoupled revolute degrees-of-freedom with a common remote center of motion located at a distance from the second manipulator, and means for selectively locking and releasing the separate degrees-of-freedom small rotational realignments of an end effector connected to the second manipulator can be provided without requiring large motions of a manipulator joint.

2. An apparatus as in claim 1 wherein the coarse motion manipulator is adapted to provide six degrees-of-freedom.

3. An apparatus as in claim 2 wherein the fine motion manipulator is adapted to provide at least three linear degrees-of-freedom.

4. An apparatus as in claim 2 wherein the coarse motion manipulator has a three degree-of-freedom rotational manipulator.

5. An apparatus as in claim 4 wherein the fine motion manipulator is connected to the coarse motion manipulator's rotational manipulator wherein a center of rotation of the second manipulator can be aligned over a target area and, the fine motion manipulator can be used to move the end effector with natural motions of a task.

6. An apparatus as in claim 1 wherein the coarse motion manipulator is adapted to provide at least three orthogonally decoupled paths of linear motion.

7. An apparatus as in claim 1 wherein the fine motion manipulator is adapted to provide at least three orthogonally decoupled paths of linear motion.

8. An apparatus as in claim 1 wherein the second manipulator includes two crossed goniometer cradle sections having axes of rotation at a common point.

9. An apparatus as in claim 1 wherein the second manipulator includes at least two goniometer cradle sections and at least two rotary axis sections having axes of rotation that intersect at a common point with axes of rotation of the goniometer cradle sections.

10. An apparatus as in claim 1 further comprising means for selectively applying a braking force to a joint of at least one of the manipulators to restrict a degree-of-freedom.

11. An apparatus as in claim 10 wherein the means for selectively applying a braking force is adapted to provide a variable braking force.

12. An apparatus as in claim 10 wherein the means for selectively applying a braking force includes a computer and computer controlled brakes.

13. An apparatus as in claim 10 wherein the means for selectively applying a braking force includes manually actuatable locks.

14. An apparatus as in claim 10 further comprising at least one micrometer adjuster adapted to provide motion at the joint when the joint is locked by the means for selectively applying a braking force.

15. An apparatus as in claim 1 further comprising a force sensor adapted to sense force being applied to the patient by an end effector connected to the second manipulator.

16. An apparatus as in claim 1 further comprising means for direct endpoint sensing of the location of an end effector connected to the second manipulator.

17. An apparatus for use in moving a surgical instrument relative to a patient, the apparatus comprising;

a base;

a first link movably mounted to the base for movement along a first axis of motion;

a second link movably mounted to the first link for movement along a second axis of motion perpendicular to the first axis of motion;

a third link movably mounted to the second link for movement along a third axis of motion perpendicular to the first and second axes of motion;

a fine adjustment manipulator comprising a first section movably mounted to the third link along a forth axis of motion, a second section movably mounted to the first section along a fifth axis of motion perpendicular to the fourth axis of motion, and a third section movably mounted to the second section along a sixth axis of motion perpendicular to the fourth and fifth axes of motion;

means for selectively locking and unlocking movement of individual links and sections to provide orthogonal only movement between connected links and sections upon unlocking of the links and sections; and

a rotational manipulator connected to the fine adjustment manipulator adapted to provide multiple orthogonally decoupled revolute degrees-of-freedom.

18. An apparatus as in claim 17 wherein the means for selectively locking an unlocking includes manually actuatable locks.

19. An apparatus as in claim 17 wherein the means for selectively locking and unlocking includes computer controlled brakes.

20. An apparatus as in claim 19 further comprising means for manually actuating the brakes.

21. An apparatus for assisting a surgeon in manipulating a surgical instrument intended to be placed into a patient's body through an opening in which there is a relatively small amount of available lateral motion at the opening, the apparatus comprising:

a first manipulator;

a second manipulator connected to the first manipulator, the second manipulator comprising at least three orthogonally decoupled revolute degrees-of-freedom and being positionable relative to the opening to provide a center of motion at the opening, means for connecting the surgical instrument to the second manipulator, and means for controlling movement of members of the second manipulator, the means for controlling movement comprising a computer-controlled device including at least one motion driver attached to at least one of the members adapted to drive the two members relative to each other;

a computer controller connected to the computer-controlled motion driver to control activation of the motion driver, the computer controller being adapted to automatically actuate the motion driver to move the two members; and

sensors connected to the computer controller for indicating position of the members of the second manipulator wherein the surgical instrument comprises a camera and the computer controller is adapted to move the second manipulator to track a target with the camera.

22. An apparatus as in claim 21 wherein the second manipulator includes means for longitudinally axially moving the surgical instrument relative to the second manipulator along longitudinal axis of the surgical instrument.

23. An apparatus as in claim 21 wherein the second manipulator includes a distal end section adapted to provide a fourth revolute degree-of-freedom.

24. An apparatus as in claim 21 wherein the second manipulator includes at least one micrometer adjustment mechanism.

25. An apparatus as in claim 21 wherein the computer-controlled device includes at least one selectively actuatable motion brake.

26. An apparatus as in claim 21 further comprising means for inputting information by the surgeon directly into the computer controller during surgery.

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to surgery and, more particularly, to a system and method for positioning, moving and locating surgical instruments for performing surgery on a patient.

2. Prior Art

Recent advances in medical imagining technology (CT, MRI, PET, etc.), coupled with advances in computer-based image processing and modelling capabilities have given physicians an unprecedented ability to visualize anatomical structures in live patients, and to use this information in diagnosis and treatment planning. The precision of image-based pre-surgical planning often greatly exceeds the precision of actual surgical execution. Precise surgical execution has been limited to procedures, such as brain biopsies, in which a suitable sterotactic frame is available. The inconvenience and restricted applicability of such a frame or device has led many researchers to explore the use of robotic devices to augment a surgeon's ability to perform geometrically precise tasks planned from computed tomography (CT) or other image data. The ultimate goal of this research is partnership between a man (the surgeon) and machines (computers and robots), that seeks to exploit the capabilities of both, to do a task better than either can do alone. Machines are very precise and untiring and can be equipped with any number of sensory feedback devices. Numerically controlled robots can move a surgical instrument through an exactly defined trajectory with precisely controlled forces. On the other hand, the surgeon is very dexterous. He is also quite strong, fast, and is highly trained to exploit a variety of tactile, visual, and other cues. "Judgementally" controlled, the surgeon understands what is going on in the surgery and uses his dexterity, senses, and experience to execute the procedure. However, the surgeon usually wants to be in control of everything that goes on. If the surgeon desires to increase precision within acceptable limits of time or with sufficient speed, he must be willing to rely on machines to provide the precision.

One potential problem with a robotic device is undesired motion. The most obvious way to prevent a robotic device from making an undesired motion is to make it incapable of moving of its own accord. Motor-less manipulators have been implemented in the past which use joint encoders to provide feedback to the surgeon on where his instruments are relative to his image-based surgical plan. European Patent Application 326,768A2 describes one such device. One important limitation of this approach is that it is often very difficult for a person to align a tool accurately in six degrees-of-freedom with only the use of positional feedback. Passive manipulators, permitting free motion until locked, have also been implemented in the past for limb positioning, tissue retraction, instrument holding, and other applications in which accuracy is not important. A three degree-of-freedom passive manipulation aid for prostate surgery has also been used clinically in the past.

In cases where only a single motion axis is required during the "in contact" phase of the surgery, a robot has been used in the past essentially as a motorized sterotactic frame. A passive tool guide is placed at the desired position and orientation relative to the patient. Brakes are applied and robot power is turned off before any instrument touches the patient. The surgeon provides whatever motive force is needed for the surgical instruments themselves and relies on his own tactile senses for further feedback in performing the operation. This approach ameliorates, but does not entirely eliminate, the safety issue raised by the presence of an actively powered robot in close proximity to to the patient and operating room personnel. Furthermore, maintaining accurate positioning is not always easy, since many robots tend to "sag" a bit when they are turned off or to "jump" when brakes are applied. Leaving power turned on and relying on the robot's servocontroller to maintain position introduces further safety exposures. Finally, this type of approach is limited to cases where a fixed passive guide suffices. The surgeon cannot execute a complex pre-computed trajectory by use of this approach, nor can he precisely relocate an instrument or body part from one place to another.

Over the past several years, researchers at IBM and the University of California at Davis developed an image-directed robotic system to augment the performance of human surgeons in precise bone machining procedures in orthopedic surgery, with cementless total hip replacement surgery as an initial application. This application inherently requires computer controlled motion of the robot's end-effector while it is in contact with the patient. Thus, considerable attention had to be paid to safety checking mechanisms. In-vitro experiments conducted with this system demonstrated an order of-magnitude improvement in implant fit and placement accuracy, compared to standard manual preparation techniques. A clinical trial on dogs needing hip replacement operations is presently underway.

It is the objective of the present invention to provide a new and improved system and method for augmentation of surgery.

SUMMARY OF THE INVENTION

The foregoing problems are overcome and other advantages are provided by a new and improved system and method for augmentation of surgery.

In accordance with one embodiment of the present invention, an apparatus for use in moving an end effector is provided. The apparatus comprises a first manipulator and a second manipulator. The first manipulator comprises a coarse motion manipulator and a fine motion manipulator. The second manipulator is connected to a distal end of the first manipulator. The second manipulator has means for providing orthogonally decoupled degrees of freedom with a common remote center-of-motion located at a work point some distance from the manipulator mechanism, means for selectively locking or releasing the separate degrees of freedom, and arranged so that small rotational realignments of an end effector connected to the end of the second manipulator can be provided without requiring large motions of any manipulator joint. This mechanism provides at least three orthogonally decoupled revolute degrees of freedom, together with additional linear degrees of freedom.

In accordance with another embodiment of the present invention, a system for manipulating movement of a surgical instrument is provided. The system comprises a mechanical positioner, a computer controlled brake, a computer, and means for signaling the computer. The mechanical positioner is adapted to have the surgical instrument connected thereto and comprises a plurality of members connected to each other in a series with at least one motion joint between two of the members. The computer controlled brake is located at the motion joint. The computer is connected to the brake for selectively actuating the brake upon an occurrence of a predetermined event. The means for signaling the computer can signal the computer of the occurrence of the predetermined event.

In accordance with another embodiment of the present invention, a system for assisting the surgeon in positioning a surgical instrument relative to a target position is provided. The system comprises means for manipulating the position of a surgical instrument, means for sensing the position of the surgical instrument, means for determining a path from a sensed position of the surgical instrument to the target position, and means for audibly signaling deviation of the position of the surgical instrument from the path.

In accordance with another embodiment of the present invention, a system for assisting a surgeon in positioning an article relative to a target position is provided. The system comprising means for determining a surgical plan based upon input patient information, means for sensing surgical execution of the surgical plan by the surgeon, means for advising the surgeon and means for automatically selecting different types of advice.

The means for advising the surgeon can advise the surgeon based upon comparison of the surgical plan and the sensed surgical execution. The means for automatically selecting different types of advice can select different types of advice to give the surgeon based upon the surgical plan and the sensed surgical execution.

In accordance with another embodiment of the present invention, a system for assisting a surgeon during surgery is provided. The system comprises means for determining a surgical plan based upon input patient information, means for sensing surgical execution of the surgical plan by the surgeon, means for advising the surgeon, and means for inputting a change in the surgical plan. The means for advising the surgeon can advise the surgeon of the surgical plan and the sensed surgical execution during the surgery. The means for advising comprises a computer. The means for inputting a change in the surgical plan can input a change in the surgical plan into the computer during surgery and determine a new surgical plan based, at least partially, upon previously sensed surgical execution of the surgical plan.

In accordance with another embodiment of the present invention, an apparatus for moving a surgical instrument relative to a patient is provided. The apparatus comprises a base, a first link, a second link, a third link, a fine adjustment manipulator, and means for selectively locking and unlocking movement. The first link is movably mounted to the base for movement along a first axis of motion. The second link is movably mounted to the first link for movement along a second axis of motion perpendicular to the first axis of motion. The third link is movably mounted to the second link for movement along a third axis of motion perpendicular to the first and second axes of motion. The fine adjustment manipulator comprises a first section movably mounted to the third link along a fourth axis of motion. The fine adjustment manipulator also comprises a second section movably mounted to the first section along a fifth axis of motion perpendicular to the fourth axes of motion, and a third section movably mounted to the second section along a sixth axis of motion perpendicular to the