US 8048088 B2
The invention is directed to manipulator assembly (2) for holding and manipulating a surgical instrument (14) in a telerobotic system. The assembly comprises a base (6) fixable by passive or power driven positioning devices to a surface, such as an operating table, and an instrument holder (4) movably mounted on the base. The instrument holder comprises a chassis (6) and an instrument support (70) movably mounted on the body and having an interface engageable with the surgical instrument to releasably mount the instrument to the instrument holder. A drive assembly (7) is operatively coupled to the instrument holder for providing the instrument with at least two degrees of freedom. The instrument holder is separable from the base and the drive assembly so that the holder can be sterilized. The assembly further includes a force sensing element (52) mounted distal to the holder and the drive assembly for detecting forces exerted on the surgical instrument and providing feedback to the surgeon. The assembly is attached to a remote center positioner (300) for constraining the instrument to rotate a point coincident with the entry incision and an inclinometer (350) for preventing gravitational forces acting on the system's mechanisms from being felt by the surgeon.
1. A manipulator assembly for holding and manipulating a surgical instrument, the assembly comprising:
a surgical instrument;
an instrument holder having an interface engageable with the surgical instrument to releasably mount the instrument to the instrument holder;
a base coupled to a positioning device, the instrument holder movably mounted on the base; and
a force sensing element mounted on the holder for detecting forces exerted on the surgical instrument and providing force feedback to a user of the manipulator assembly.
2. The assembly of
3. The assembly of
4. The assembly of
a first linkage pivotally mounted on said base for rotation about an axis, said instrument holder holding said instrument in a position so that the desired remote center of spherical rotation along the instrument intersects said axis; and
a second linkage connected to said instrument holder for moving said instrument holder in a parallel-plane relationship to said second linkage, said second linkage being pivotally connected to said first linkage so that said second linkage remains parallel to said axis and said first linkage remains parallel to the instrument;
wherein said first and second linkages constrain movement of said instrument, such that said desired location on said instrument remains fixed at said spherical center of rotation.
5. The assembly of
6. The assembly of
7. The assembly of
8. The assembly of
9. The assembly of
10. The assembly of
an elongate shaft having a proximal portion, a distal portion, an inner lumen, and at least one axially extending slot;
an end effector disposed adjacent the distal portion of the elongate shaft; and
an actuator assembly comprising a linkage disposed within the inner lumen and a movable actuator pin laterally extending from the linkage and extending through the axially extending slot to releasably couple the actuator assembly to a driver of the instrument holder.
11. A method of performing a surgical procedure comprising:
releasably coupling a surgical instrument to a manipulator assembly comprising a plurality of linkages and joints;
operatively coupling at least one moveable actuator element of said surgical instrument with a driver on said manipulator assembly;
introducing a distal portion of said surgical instrument through a percutaneous penetration into the patient, said distal portion comprising an end effector;
articulating said end effector of said surgical instrument relative to said proximal portion and within said patient's body;
actuating said end effector by displacing said at least one moveable actuator element;
sensing forces exerted on the surgical instrument; and
transmitting feedback signals to an input device based on the sensed forces on the surgical instrument.
12. The method of
13. The method of
14. The method of
15. The method of
16. The method of
This application is a continuation of application Ser. No. 11/186,654, filed Jul. 20, 2005, now U.S. Pat. No. 7,648,513, which is a division of application Ser. No. 10/629,345, filed Jul. 28, 2003 (abandoned), which is a continuation of application Ser. No. 10/124,573, filed Apr. 16, 2002, now U.S. Pat. No. 6,620,174, which is a division of application Ser. No. 09/104,935, filed Jun. 25, 1998, now U.S. Pat. No. 6,413,264, which is a continuation of application Ser. No. 08/824,977, filed Mar. 27, 1997, now U.S. Pat. No. 5,814,038, which is a continuation of application Ser. No. 08/487,020 filed Jun. 7, 1995 (abandoned), the full disclosures of which are incorporated herein by reference.
The invention was made with Government support un Grant Number 5R01 GM44902-2 awarded by the National Institutes of Health. The Government has certain rights in this invention.
This invention relates to surgical manipulators and more particularly to robotically-assisted apparatus for use in surgery.
In standard laparoscopic surgery, a patient's abdomen is insufflated with gas, and trocar sleeves are passed through small (approximately ½ inch) incisions to provide entry ports for laparoscopic surgical instruments. The laparoscopic surgical instruments generally include a laparoscope for viewing the surgical field, and working tools such as clamps, graspers, scissors, staplers, and needle holders. The working tools are similar to those used in conventional (open) surgery, except that the working end of each tool is separated from its handle by an approximately 12-inch long extension tube. To perform surgical procedures, the surgeon passes instruments through the trocar sleeves and manipulates them inside the abdomen by sliding them in and out through the sleeves, rotating them in the sleeves, levering (i.e., pivoting) the sleeves in the abdominal wall and actuating end effectors on the distal end of the instruments.
In robotically-assisted and telerobotic surgery (both open and endoscopic procedures), the position of the surgical instruments is controlled by servo motors rather than directly by hand or with fixed clamps. The servo motors follow the motions of a surgeon's hands as he/she manipulates input control devices and views the operation via a displayed image from a location that may be remote from the patient. The servo motors are typically part of an electromechanical device or surgical manipulator that supports and controls the surgical instruments that have been introduced directly into an open surgical site or through trocar sleeves into a body cavity, such as the patient's abdomen. During the operation, the surgical manipulator provides mechanical actuation and control of a variety of surgical instruments, such as tissue graspers, needle drivers, etc, that each perform various functions for the surgeon, i.e., holding or driving a needle, grasping a blood vessel or dissecting tissue.
This new method of performing telesurgery through remote manipulation will create many new challenges. One such challenge is transmitting position, force, and tactile sensations from the surgical instrument back to the surgeon's hands as he/she operates the telerobotic system. Unlike other techniques of remote manipulation, telesurgery can give the surgeon the feeling that he/she is manipulating the surgical instruments directly by hand. For example, when the instrument engages a tissue structure or organ within the patient, the system should be capable of detecting the reaction force against the instrument and transmitting this force to the input control devices. In this manner, the surgeon can see the instrument contacting the tissue structure on the displayed image and directly feel the pressure from this contact on the input control devices. Providing the appropriate feedback, however, can be problematic because of other forces acting on the system, such as friction within the telerobotic mechanisms, gravity and inertial forces acting on the surgical manipulator or forces exerted on a trocar sleeve by the surgical incision.
In addition, to enable effective telesurgery, the manipulator must be highly responsive and must be able to accurately follow even the most rapid hand motions that a surgeon frequently uses in performing surgical procedures. To achieve this rapid and responsive performance, a telerobotic servo system must be designed to have an appropriately high servo bandwidth which requires that the manipulator be designed to have low inertia and to employ drive motors with relatively low ratio gear or pulley couplings.
Another challenge with telesurgery results from the fact that a portion of the electromechanical surgical manipulator will be in direct contact with the surgical instruments, and will also be positioned adjacent the operation site. Accordingly, the surgical manipulator may become contaminated during surgery and is typically disposed of or sterilized between operations. Of course, from a cost perspective, it would be preferable to sterilize the device. However, the servo motors, sensors and electrical connections that are necessary to robotically control the motors typically cannot be sterilized using conventional methods, e.g., steam, heat and pressure or chemicals, because they would be damaged or destroyed in the sterilization process.
What is needed, therefore, is a robotically-assisted apparatus for holding and manipulating surgical instruments by remote control. The apparatus should be configured for easy sterilization so that it can be reused after it has been contaminated during an operation. The apparatus should be further capable of providing the surgeon with the appropriate feedback from forces transmitted to and from the surgical instrument during the telerobotic operation and it should be configured to compensate for gravitational forces acting on the apparatus so that these forces are not felt by the surgeon. In addition, the apparatus must be highly responsive and must be able to accurately follow even the most rapid hand motions that a surgeon frequently uses in performing surgical procedures.
According to the invention, an apparatus is provided for holding and manipulating a surgical instrument during conventional open surgery or endoscopic procedures, such as laparoscopy. The apparatus comprises a support base fixable by means of various passive or power driven positioning devices to a surface, such as an operating table, and an instrument holder movably mounted on the base. The instrument holder comprises a body and an instrument support movably coupled to the body and having an interface engageable with the surgical instrument to releasably mount the instrument to the instrument holder. A drive assembly is operatively coupled to the instrument holder for providing the instrument with at least two degrees of freedom. The drive assembly includes a first drive for moving the instrument support and a second drive for moving the instrument holder relative to the support base. The apparatus includes means for removably coupling the instrument holder from the base and the drive assembly so that the holder can be separated from the rest of the device and sterilized after a surgical procedure.
In a specific configuration, the support base includes a frame with distal and proximal support members and a pair of shafts rotatably mounted within the support members. The instrument holder is slidably mounted on the support shafts for axial movement of the instrument. In addition, the shafts are each coupled to a drive motor for providing the instrument with second and third degrees of freedom, e.g., rotation and end effector actuation. The drive motors are coupled to the proximal support member so that they will not be contaminated during surgery. The rotatable shafts can be removed by sliding them upward and out of engagement with their lower bearings and the instrument holder so that the instrument holder can be easily removed from the support base for sterilization. The lower portion of the support base (including the distal support member) may also be sterilized to decontaminate those parts that have contacted the instrument holder. In this manner, the surgical manipulator can be easily sterilized after a surgical procedure without damaging the servo motors or the electrical connections required for the telerobotic system.
The support base further comprises a sleeve, such as a cannula or trocar sleeve, mounted on the distal support member. The sleeve has an axial passage for receiving the instrument therethrough and a force sensing element mounted within the axial passage near the distal end of the sleeve. The force sensing element is configured to detect lateral forces exerted on the element by the distal portion of the instrument during surgery. Since the force sensing element is mounted distal to the remainder of the apparatus, it is undisturbed by forces that may be exerted on the cannula by the surgical incision or by gravity and inertial forces that act on the instrument holder. When supported by a positioning device, the surgical manipulator can be used with an inclinometer to determine the true orientation of the instrument holder with respect to the direction of the local gravitational field. Use of the inclinometer and force sensors with the manipulator facilitates the design of a telerobotic system in which the surgeon will directly sense the forces acting against the end of the instrument, unaffected by extraneous forces acting on the telerobotic mechanism. In other words, the surgeon will feel as if his/her hands are holding the instrument at the point in which the instrument contacts the force sensing element.
The invention is particularly useful for holding and manipulating a surgical instrument having an end effector, such as a pair of jaws, coupled to the distal end of the instrument shaft. To that end, the instrument holder further includes an actuator driver having an interface engageable with an end effector actuator on the instrument. The actuator driver includes a coupling that connects the driver to the drive assembly for axially moving a portion of the driver relative to the support base, thereby actuating the end effector of the instrument. In a preferred configuration, the coupling is a concentric helical actuator that translates rotation from a drive motor into axial movement of the end effector actuator. Because of the symmetrical design of the helical actuator, the actuation force applied by the drive motor will not generate any effective side loads on the instrument, which avoids frictional coupling with other degrees of freedom such as axial movement and rotation of the instrument.
Other features and advantages of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawings.
Referring to the drawings in detail, wherein like numerals indicate like elements, a manipulator assembly 2 is illustrated according to the principles of the invention. Manipulator assembly 2 generally includes an instrument holder 4 removably mounted to a base 6 and a drive assembly 7 for manipulating a surgical instrument 14 releasably coupled to instrument holder 4.
First drive 8 comprises a rotation drive motor 26 fixed to frame 16 and coupled to first shaft 18 by a drive belt 28 for rotating first shaft 18 with respect to frame 16. Second drive 10 comprises a gripper drive motor 30 fixed to frame 16 and coupled to second shaft 20 by a drive belt 32 for rotating second shaft 20 with respect to frame 16. Third drive 12 comprises a vertical drive motor 34 coupled to instrument holder 4 via a drive belt 36 and two pulleys 38 for axially displacing instrument holder 4 with respect to frame 16. Drive motors 26, 30, 34 are preferably coupled to a controller mechanism via servo-control electronics (not shown) to form a telerobotic system for operating surgical instrument 14 by remote control. The drive motors follow the motions of a surgeon's hands as he/she manipulates input control devices at a location that may be remote from the patient. A suitable telerobotic system for controlling the drive motors is described in commonly assigned co-pending application Ser. No. 08/823,932 filed on Jan. 21, 1992, entitled TELEOPERATOR SYSTEM AND METHOD, which is incorporated herein by reference.
The above described telerobotic servo system preferably has a servo bandwidth with a 3 dB cut off frequency of at least 10 Hz so that the system can quickly and accurately respond to the rapid hand motions used by the surgeon. To operate effectively with this system, instrument holder 4 has a relatively low inertia and drive motors 26, 30, 34 have relatively low ratio gear or pulley couplings.
In a specific embodiment, surgical instrument 14 is an endoscopic instrument configured for introduction through a percutaneous penetration into a body cavity, such as the abdominal or thoracic cavity. In this embodiment, manipulator assembly 2 supports a cannula 50 on distal support member 19 of frame 16 for placement in the entry incision during an endoscopic surgical procedure (note that cannula 50 is illustrated schematically in
As shown in
As shown in
Instrument holder 4 is removably coupled to base 6 and the drive motors so that the entire holder 4 can be removed and sterilized by conventional methods, such as steam, heat and pressure, chemicals, etc. In the preferred configuration, arm 68 includes a toggle switch 69 that can be rotated to release arm 68 from drive belt 36 (
To remove instrument holder 4 from base 6, the operator rotates toggle switch 69 to release arm 68 from drive belt 36 and removes drive belts 28, 32 from drives 8, 10. As shown in
The lower portion of base 6 (including distal support member 19) may also be sterilized to decontaminate those parts that come into contact with holder 4 or instrument 14 (e.g., by dipping the lower portion of base 6 into a sterilizing bath). To facilitate this type of sterilization, shafts 18, 20 will preferably be somewhat longer than shown in
Instrument holder 4 further includes an instrument support 70 (see detail in
Instrument holder 4 further includes an actuator driver 80 (see detail in
Shaft 100 is preferably a stainless steel tube having an outer diameter in the range of 2-10 mm, usually 4-8 mm, so as to fit within a cannula having an internal diameter in the range of 2-15 mm. Shaft 100 can also be introduced directly through a percutaneous incision in the patient. Shaft 100 has a length selected to reach a target site in a body cavity, such as the abdomen, and to extend sufficiently out of the body cavity to facilitate easy manipulation of surgical instrument 14. Thus, shaft 100 should be at least between 10 cm and 40 cm and is preferably between 17 cm and 30 cm. It should be noted that although shaft 100 is shown as having a circular cross-sectional shape in the drawings, shaft 100 could alternatively have a rectangular, triangular, oval or channel cross-sectional shape.
In a specific configuration, shaft 100 includes a mounting means for releasably coupling surgical instrument 14 to instrument support 70 and first drive 8 of manipulator assembly 2. In the preferred embodiment, mounting means comprises a pair of opposed mounting pins 116 extending laterally outward from shaft 100. Mounting pins 116 are rigidly connected to shaft 100 and are adapted for engaging a twist-lock interface on instrument support 70, as discussed in detail below. It should be understood that the invention is not limited to a pair of opposing pins and mounting means can include a single mounting pin or a plurality of pins extending circumferentially around shaft. Alternatively, pins 116 may have a variety of other shapes, such as spherical or annular, if desired.
Instrument 14 includes an end effector 120 extending from distal end 104 for engaging a tissue structure on the patient, such as the abdomen during laparoscopic surgery. In the preferred embodiment, end effector 120 comprises a pair of jaws 122, 124 that are movable between open and closed positions for grasping a blood vessel, holding a suture, etc.
Jaws 122, 124 preferably have transverse grooves or other textural features (not shown) on opposing surfaces to facilitate gripping of the tissue structure. To avoid the possibility of damaging the tissue to which jaws 122, 124 are applied, the jaws may also include a traumatic means (not shown), such as elastomeric sleeves made of rubber, foam or surgical gauze wrapped around jaws 122, 124.
To move jaws 122, 124 between the open and closed positions, instrument 14 includes an end effector actuator releasably coupled to actuator driver 80 and second drive 10 of manipulation assembly 2 (see
Jaws 122, 124 are preferably biased into the closed positioned by an annular compression spring 144 positioned within shaft 100 between actuator pins 132 and an annular disc 146 fixed to the inside surface of shaft 100. During endoscopic procedures, this allows the surgical team to introduce jaws 122, 124 through cannula 50 (or any other type of percutaneous penetration) and into the body cavity without getting stuck within cannula 50 or damaging surrounding tissue.
As shown in
Button 214 is disposed on the upper surface of support 70 for manual actuation by the surgeon or automatic actuation by base 6. Preferably, when instrument holder 4 is moved to its most proximal position (see
The intersecting axial and locking slots 204, 206 form an interface for releasably coupling mounting pins 116 of surgical instrument 14 to instrument holder 4. To insert instrument 14, the surgeon aligns mounting pins 116 with axial slot 204 and slides the instrument through bore 202 of annular collar 200 until mounting pins 116 are aligned with locking slots 206, as shown in
As shown in
As shown in
As shown in
As shown in
A first linkage means is indicated generally by the numeral 321 and a second linkage in the form of a parallelogram is indicated by the numeral 323. The first linkage means is pivotally mounted on a base plate for rotation about an x-x axis. The second linkage means is pivotally connected to the first linkage means and is adapted to move in a plane parallel to the first linkage. Five link members (including extensions thereof), 311, 312, 313, 314, and 315 are connected together with pivot joints 316-320. A portion of element 313 extends beyond pivot 320 of the parallelogram linkage. The parallelogram linkage has an operating end at link member 313 and a driving end at link member 312. The elongated element 313 may, as desired later, carry a surgical instrument or other device, such as support bracket 24 of manipulator assembly 2. The pivot joints allow relative motion of the link members only in the plane containing them.
A parallelogram linkage is formed by corresponding link members 314, 315 and link members 312 and 313. The portions of link members 314 and 315 of the parallelogram are of equal length as are the portions of members 312 and 313 of the parallelogram. These members are connected together in a parallelogram for relative movement only in the plane fowled by the members. A rotatable joint generally indicated by the numeral 322 is connected to a suitable base 324. The rotatable joint 322 is mounted on a base plate 326 adapted to be fixedly mounted to the base support means 324. A pivot plate 328 is pivotally mounted to base plate 326 by suitable means at, such as, pivots 330, 332. Thus pivot plate 328 may be rotated about axis x-x through a desired angle 82. This may be accomplished manually or by a suitable pivot drive motor 334.
A first linkage is pivotally mounted on the pivot plate 328 of the rotatable joint 322. The linkage elements 311, 312 and the link members are relatively stiff or inflexible so that they may adequately support an instrument used in surgical operations. Rods made of aluminum or other metal are useful as such links. The linkage elements 311 and 312 are pivotally mounted on base plate 328 for rotation with respect to the rotatable joint by pivots 336 and 338. At least one of the pivots 336, 338 is positioned so that its axis of rotation is normal to and intersects the x-x axis. Movement may occur manually or may occur using a linkage drive motor 340. The first linkage is also shaped in the form of a parallelogram formed by linkage elements 311, and 312; the portion of link member 315 connected thereto by pivots 316, 318; and base plate 328. One of the link members 315 is thus Linkage element 312 also forms a common link of both the first linkage means 321 and the second linkage means 323. In accordance with the invention, a remote center of spherical rotation 308 is provided by the above described embodiment of apparatus when the linkage element 311 is rotated and/or when pivot plate 328 is rotated about axis x-x. Thus, the end of element 313 can be moved through desired angles 81 and 82 or rotated about its own axis while the remote center of rotation remains at the same location.
Reference now is made to
Variations and changes may be made by others without departing from the spirit of the present invention. For example, it should be understood that the present invention is not limited to endoscopic surgery. In fact, instrument holder 4, along with a telerobotic control mechanism, would be particularly useful during open surgical procedures, allowing a surgeon to perform an operation from a remote location, such as a different room or a completely different hospital.