Patent Application
20100268249
Conventional devices which are used to perform very complex and/or physically demanding surgical procedures like neurosurgery, spine surgery, ear surgery, head and neck surgery, hand surgery and minimally invasive surgical procedures have a number of drawbacks as it relates to the dexterity of the surgeon. For example, the surgeon can easily become fatigued by the need to manually support the surgical device during its use. Additionally, the surgeon may have to orient his hands in an awkward position in order to operate the device. Furthermore, conventional devices used in such surgical procedures can produce angular magnification of errors. As a result, a surgeon has considerably less dexterity and precision when performing an operation with such surgical devices than when performing an operation by traditional techniques in which the surgeon grasps a tool directly.
Accordingly, there is an increasing interest in the use of powered manipulators, such as robotic and master-slave manipulators for supporting and manipulating surgical tools during medical procedures. Such manipulators can provide a number of advantages to both patients and medical practitioners. In particular, a master/slave controlled manipulator can enhance the dexterity of the surgeon/operator so as to allow the surgeon to manipulate a medical tool with greater dexterity than he could if he was actually holding the tool in his hands. A manipulator can also reduce the fatigue experienced by a surgeon, since it eliminates the need for the surgeon to physically support the medical tool or device during its use. Additionally, the surgeon can let go of the manipulator and perform other tasks without the medical tool undergoing movement, which increases the efficiency of the surgeon and can reduce the number of individuals that are necessary to perform a particular procedure. Thus, manipulators can allow medical procedures to be performed much more rapidly, resulting in less stress on the patient.
However, the use of powered manipulators in medical, and in particular surgical, procedures raises other issues. One such issue relates to sterilization. Medical instruments or tools that become contaminated during a medical procedure must be sterilized before being used with another patient or discarded. In most cases, discarding a powered manipulator after a single use is not economically feasible. Yet, in many cases, sterilizing a powered manipulator is also not a realistic option due to the size of the manipulator or the complexity of its electronics.
One way in which to address this issue is with a sterile barrier that isolates some of the equipment from the contaminated environment so that it does not have to be sterilized. However, it can be difficult to adapt medical manipulators so that they can operate with a sterile barrier in an efficient and cost effective manner.
The invention provides a surgical system for use in performing medical procedures on a body of a patient. The system includes a manipulator having a tool mounting arrangement including a power transmitter. The manipulator is capable of moving the tool mounting arrangement with at least one degree of freedom. The system has a tool support including a power receiver.
A sterile barrier is arranged between the robotic mechanism and the tool support to isolate the robotic mechanism from the sterile environment. The tool support is engageable with the tool mounting arrangement with the sterile barrier therebetween. The power transmitter and power receiver can wirelessly transmit power across the sterile barrier between the manipulator and the tool support when the tool support is engaged with the tool mounting arrangement.
The surgical system can further include a retention mechanism configured for engaging the tool support with the tool mounting arrangement with the sterile barrier therebetween only when the tool support and tool mounting arrangement are in at least one desired orientation relative to each other.
The surgical system can also be configured such that the sterile barrier has a portion thereof formed to fit tightly over either a first or second component of the retention mechanism.
Referring now to
In the illustrated embodiment, the manipulator 10 is a parallel manipulator that includes an end platform 14 that carries a tool mount 16. As described in greater detail below, the tool mount 16 mates with a tool support 18 that, in turn, carries the tool. The tool support 18 is adapted such that various different tools are attachable, detachable and re-attachable to the tool support. Alternatively, the tool and tool support could be a single integral element. The end platform 14 is supported, in this case, by six links 20. A linear actuator 22 comprising a linear motor is provided for each of the links 20. In particular, each linear actuator 22 is attached to the end of its respective link 10 that is not connected to the end platform 14. The linear actuators 22 are arranged in spaced relation from each other in a generally circular pattern about a base 24. Each link 20 can be attached to the end platform 14 using a universal joint having two degrees of rotary freedom and to its respective linear actuator 22 using a universal joint having three degrees of rotary freedom. With this arrangement, the parallel mechanism 10 can manipulate the end platform 14 with six degrees of freedom by moving the links 20 through extension and retraction of one or more of the linear actuators 22.
Depending on the desired performance, the illustrated parallel manipulator 10 can have any number of links 20 and the links can have different configurations. Moreover, the links 20 can be arranged in a variety of different geometries. Additional details regarding link geometries and the structure and operation of the illustrated parallel manipulator are provided in commonly owned U.S. Pat. No. 6,330,837, the disclosure of which is incorporated herein by reference. As noted above, the present invention is not intended to be limited to any particular type of manipulator or manipulator configuration and the parallel manipulator is being described merely to illustrate one particular implementation of the invention.
In order to provide dexterity enhancement for an operator/surgeon in performing surgical and certain interventional radiology procedures, the manipulator 10 can be used as a slave robot in a master-slave robotic system. In a master-slave robotic system, a surgeon/operator provides position input signals to the “slave” manipulator via a master or haptic interface which operates through a controller or control console. Specifically, with the manipulator 10 of the present invention serving as the slave robot, the surgeon indicates the desired movement of the tool held by the manipulator 10 through the use of an input device on a haptic interface 26 such as a six degree of freedom tool handle with or without force feedback, joystick, foot pedal or the like. The haptic interface 26 relays these signals to a controller 28, which, in turn, applies various desired predetermined adjustments to the signals prior to relaying them to the slave manipulator 10. Any haptic interface having six or more degrees of freedom (DOF) can be used to control the manipulator 10 via the controller. Examples of haptic interfaces or masters which can be used with the present invention include the Freedom 6S available from MPB Technologies of Montreal, Canada, and other haptic interfaces commercially available from Sensable Technology of Cambridge, Mass. and MicroDexterity Systems of Albuquerque, N.M.
Based on the signals provided by the controller 28, the manipulator 10 executes the desired movement or operation of the tool. Thus, any desired dexterity enhancement can be achieved by setting up the controller 28 to perform the appropriate adjustments to the signals sent from the haptic interface 26. For example, this can be accomplished by providing the controller with software which performs a desired dexterity enhancement algorithm. Software dexterity enhancement algorithms can include position scaling (typically downscaling), force scaling (up-scaling for bone and cartilage, downscaling for soft tissue), tremor filtering, gravity compensation, programmable position boundaries, motion compensation for tissue that is moving, velocity limits (e.g., preventing rapid movement into brain, nerve or spinal cord tissue after drilling through bone), and, as discussed in greater detail below, image referencing. These and other examples of possible algorithms are well known in the field of robotics and described in detail in published literature. The ZMP SynqNet® Series Motion Controllers which employ the SynqNet system and are available from Motion Engineering of Santa Barbara, Calif. are one example of a suitable controller for use with the present invention (see www.synqnet.org and www.motioneng.com). Another example of a suitable controller is the Turbo PMAC available from Delta Tau Data Systems of Northridge, Calif.
In accordance with one aspect of the present invention, the manipulator 10 can be adapted to operate with an associated sterile barrier 12 that isolates the manipulator 10 from the medical tool that is being manipulated and the patient during a medical procedure. The sterile barrier 12 protects the manipulator 10 from contamination and thus, there is no need to sterilize the manipulator after each use. The medical tools carried by the manipulator 10 which come in contact with the patient, in turn, have to be sterilized if they are to be re-used. To this end, the medical tools can be designed to be reusable, limited reuse or disposable. In the illustrated embodiment, the sterile barrier 12 is in the form of a drape that can be arranged around the manipulator 10. The sterile drape can be made of a thin, plastic material that is formed in a known manner from medical polymers.
Along with imparting motion, the manipulator 10 also can provide power to the medical tool. For instance, the medical tool can be a tool such as a saw, drill or laser that requires power to operate. Alternatively, the tool may having moving parts that are conventionally human powered (e.g., forceps, scissors, etc.), but have been adapted to be powered by an actuator. In either case, the power for operating the tools preferably is supplied through the manipulator. Additionally, it is often desirable that information or data be exchanged between the manipulator and the tool. For example, control signals may be directed from the manipulator to the tool or feedback signals generated from sensors on the tool may be directed from the tool back to the manipulator.
To allow for the transmission of power and information between the manipulator and the tool and otherwise facilitate the physical and electrical connection between the manipulator and the tool, some known surgical manipulator and sterile drape arrangements provide openings in the drape. These openings allow for a direct physical engagement between the manipulator and the tool. However, because of these openings, such drapes provide less than ideal protection against contamination. Moreover, such drape and manipulator arrangements can require more expensive tools because the tools must have electrical contacts that mate with electrical contacts on the manipulator on the other side of the sterile drape in order to transmit power between the manipulator and the tool. This expense can be a significant problem if the tools are designed to be disposable.
One significant advantage of the present invention is that the sterile barrier 12 can be designed as a continuous, solid barrier that does not have any openings. Such a solid barrier can be provided because the tool mount 16 of the manipulator 10 and the tool support 18 for the medical tool are adapted to transmit power wirelessly across a gap and through the sterile barrier 12 such that the sterile barrier can extend unbroken between the tool mount 16 and the tool support 18. In this regard, the tool mount 16 includes a power transmitter and the tool support 18 includes a power receiver.
In the illustrated embodiment, this wireless and contactless transmission of power is achieved via inductive coupling between the tool mount 16 and the tool support 18. As shown in
As shown in
The tool support receptacle and the mounting pin are configured such that the mounting pin can engage in the receptacle with the sterile barrier draped over the mounting pin as shown in
When the mounting pin 42 is engaged with the receptacle 44 and in the position shown in
In the illustrated embodiment, a second wireless and contactless “coupling” between the tool support 16 and the tool mount 18 is used to transmit information or data between the two components. Such information or data could comprise control signals, feedback information, etc. such as for use with “smart” medical instruments. In the embodiment shown in
Other wireless and contactless transmission methods also could be used for the data “coupling” in place of or in combination with the optical fiber coupling. A radio frequency (“RF”) coupling also could be used. In particular, as shown in the embodiment of
Another way in which light could be used to transmit data across the sterile barrier 12 is by using LEDs 70 and sensor semiconductors 72. For instance, both the tool support 18 and tool mount 16 could be provided with LEDs 70 and sensor semiconductors 72 that would be in alignment (the LEDs 70 of one component aligned with the sensor semiconductors 72 of the other component) when the tool mount 16 and tool support 18 are engaged to allow for data transfer in both directions across the sterile barrier 12. Such an arrangement is schematically shown in
As an alternative to inductive coupling, capacitive coupling could be used to transmit the power and/or data between the tool mount and the tool support. In particular, as shown in the embodiment of
Another alternative for the couplings for the power and/or data transfer between the tool mount 16 and the tool support 18 across the sterile barrier 12 is the use of a coupling based on ultrasound or other forms of modulated mechanical energy. For example, as shown in the embodiment of
The ultrasonic transmitters and receivers 70, 72, 74, 76 should be arranged on the components such that when the tool mount 16 and the tool support 18 are engaged with the sterile barrier 12 therebetween, the ultrasonic signals produced by the transmitters 70, 74 are received by the corresponding receivers 72, 76 across the sterile barrier 12 and the gap between the components necessary to accommodate the sterile barrier 12. Other forms of modulated mechanical energy could also be used to provide the necessary couplings across the barrier. For example, modulated pressure transmitted through the barrier could be used to provide the data coupling between the tool support and tool mount. Alternatively, power and data could be transferred using the same modulated mechanical energy transmitters and receivers or an alternative type of wireless transfer could be used for one of the channels such as an inductive, capacitive, RF or modulated light.
For securing the tool mount 16 to the tool support 18, a retention mechanism 58 can be provided which permits the tool support to be attached to the tool mount while maintaining the arrangement of the sterile barrier 12 between the two components. In the illustrated embodiment, as shown in
In the locked position, the locking balls 60 engage in the respective openings 64 in the mounting pin 42 so as to prevent movement of the tool support 18 relative to the tool mount 16. According to one embodiment, eight locking balls 60 are spaced around the receptacle 44 each of which engages a respective opening in the mounting pin 42. Providing eight points of engagement provides a highly precise engagement in that tool support 18 is locked to the tool mount 16 at eight separate positions about the rotary degree of freedom.
In the illustrated embodiment, the locking balls 60 are held in the locked position by an annular retention sleeve 66 that bears against the locking balls 60 and pushes them radially inward into engagement with the corresponding openings 64 on the mounting pin 42. This retention sleeve 66 is supported in surrounding relation on the tool support receptacle 44 for longitudinal movement relative to the sidewall of the receptacle. In this case, to unlock the locking balls 60, the retention sleeve 66 is pulled back in a direction away from the mounting pin 42 until a groove 68 on the inside surface of the sleeve is aligned with the locking balls. When the groove 68 on the inside surface of the sleeve 66 aligns with the locking balls 60, the locking balls are able to move radially outward into their unlocked position in which the balls are engaged with the groove on the latch and out of engagement with the openings 64 on the mounting pin. The mounting pin 42 can then be pulled out of the receptacle 44. To lock the mounting pin 42 in the receptacle 44, the retention sleeve 66 is slid forward on the receptacle 44 so that the groove 68 on the sleeve moves out of alignment with the locking balls 60 and the inside surface of the retention sleeve cams or pushes the locking balls radially inward into engagement with the openings 64 on the mounting pin. The locking balls 60 are pushed radially outward by the mounting pin 42 as it is inserted into and pulled out of the receptacle 44. The locking balls 60 should be free to move radially outward when the retention mechanism 58 is unlocked and to move radially inward when the retention mechanism is unlocked. The retention sleeve 66 is preferably spring loaded towards its locked position.
Of course, other types of retention mechanisms could be used and those skilled in the art will appreciate that the present invention is not necessarily limited to any particular type of retention mechanism. For example, if the locking balls 60 are carried on the tool mount mounting pin 42 rather than the tool support receptacle 44 a cam device comprising a secondary pin portion in the mounting pin could be used to move the locking balls into engagement with complementary openings in the tool support receptacle. Other retention mechanisms could be used as well. Additionally, it will be appreciated that the retention mechanism could be manually operable or automatically operable via electric or some other type of actuators.
Particularly if a multi-point retention mechanism is used, the cylindrical sidewall of the tool support receptacle 44 can be replaced by a plurality of spaced post elements each of which extends parallel to the center rod element 36. For example, if a retention mechanism 58 having eight locking balls is used, the tool support receptacle could be defined by eight spaced apart posts with each post carrying one of the locking balls. With such an arrangement, the magnetic circuit created by the inductive coupling would be defined in eight positions.
In order to ensure that tool mount 16 and tool support 18 can engage in only a single position or in a small number of positions relative to each other, the locking balls 60 and mating openings 64 in which the locking balls are received can be arranged so as to provide a “keyed” type of engagement between the tool mount and tool support. In particular, as shown schematically in
The specific irregular pattern shown in
Alternatively or additionally, sensors 78 that are capable of operating across the sterile barrier 12 could be used to sense the position of the tool mount 16 relative to the tool support 18 (or even the tool carried by the tool support). For example, the mounting pin 42 and tool support receptacle 44 could incorporate sensors 78 (shown schematically in
To help facilitate engagement of the tool support 16 with the tool mount 18 as well as full range of movement of the manipulator 10, the sterile barrier 12 could be formed so as to fit tightly over the tool mount 18 on the manipulator 10. More specifically, at least a portion of the sterile barrier 12 could be formed thermally or via some other method to fit tightly over the mounting pin as shown in
In order to sense the forces being applied at the medical tool, it is preferred that the system be adapted to sense force across the sterile barrier 12. One way in which this can be accomplished is to provide a force sensor on the non-sterile side of the system on the manipulator 10 that is arranged and configured to sense force being applied at the tool. With such an arrangement, the sterile barrier 12 should be sufficiently flexible that it provides a negligible force component to the overall force being sensed by the force sensor inside the sterile barrier. Alternatively, the force sensor could be incorporated into the tool on the sterile side of the sterile barrier 12 with the force data being transmitted back to the manipulator 10 through the sterile barrier 12 via the data “coupling” across the sterile barrier.
Often the tool operated by the manipulator 10 is also independently movable. Examples of such tools are scissors, forceps and the like. In order to permit the manipulator 10 to drive this independent movement (i.e., operate the scissors), the system could be designed to transmit mechanical movement through the sterile barrier 12. In particular, the sterile barrier 12 could be made sufficiently flexible and the tool mount 16 and tool support 18 could be configured such that moving components on the tool mount 16 would deflect the flexible barrier in such a manner as to actuate the tool. The movement of the moving components on the tool mount 16 would be directed by the manipulator controller 28 so that actuation of the tool would be automatically directed by the manipulator 10 and the controller 28.
An exemplary embodiment of an arrangement of the tool mount 16 and tool support 18 that would allow for mechanical actuation of a tool such as scissors 79 across the sterile barrier 12 is shown in
As noted above, the sterile barrier 12 is flexible such that when the piston 80 carried by the tool mount 16 extends the sterile barrier 12 deflects allowing the piston 80 to push on the plunger 82. The pushing action that is transmitted across the sterile barrier 12 drives the plunger 82 forward. This, in turn, operates the toggle linkage 84 so as to close the scissor mechanism. Rearward movement of the plunger 82 operates the toggle linkage 84 to open the scissor mechanism. This rearward movement could be generated, for example, by a spring that normally biases the plunger 82 rearward so as to keep the scissors 79 open. The spring force should be such that it can be overcome by the force applied by the piston 80 when it extends and pushes on the plunger 82 to close the scissor mechanism via the toggle linkage 84. When the force driving the piston 80 is relieved or removed, the plunger 82 moves rearward under the force of the spring driving the opening of the scissor mechanism. The spring then holds the scissors 79 open until the surgeon and/or manipulator controller again directs closing of the scissors and drives the piston 80 forward. The mechanism shown in
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
