Patent Application
20080281343
1. Field of the Invention
The invention relates to a surgical tool and, more particularly, to a surgical tool for cutting the anatomy of a patient.
2. Description of Related Art
Conventional cutting tools may be used to cut and/or sculpt a patient's anatomy during a surgical procedure. For example, during a knee replacement procedure, a surgeon may use a surgical burr to sculpt a tibia T and a femur F to receive a prosthetic device, such as a unicondylar knee implant 500 (shown in
One drawback of conventional cutting tools is that the rotating or oscillating cutting element of the cutting tool may impinge upon portions of the anatomy that are not intended to be cut. This may occur, for example, when a surgeon operates a conventional cutting tool in a confined anatomical space, such as during minimally invasive surgery (MIS). MIS involves the performance of surgery through incisions that are considerably smaller than incisions used in traditional surgical approaches. The small incision size reduces the surgeon's ability to view and access the anatomy and creates a confined surgical workspace. For example, in minimally invasive orthopedic joint replacement, limited visibility and limited access to the joint increase the complexity of the bone sculpting procedure and the risk that surrounding anatomy will sustain damage from unintended impingement of the cutting tool.
Another drawback of conventional cutting tools is that during a cutting operation, additional tools may be required. For example, a surgeon typically needs to introduce an irrigation tool to provide fluid to the surgical site to flush and lubricate the site. Similarly, the surgeon may need to introduce a suction tool to remove fluid and debris from the surgical site. The need for multiple separate systems to perform cutting, lubrication, and debris removal increases the complexity of the surgical procedure. For example, the simultaneous introduction of multiple tools to the surgical site crowds the surgical site, which increases the risk of damage to surrounding anatomy. In the event the surgical site is too confined to receive more than one tool at a time, the surgeon must stop cutting and remove the cutting tool before he can lubricate or remove debris from the surgical site. As a result, the length of time required to perform the surgical procedure is increased. Further, multiple separate systems may occupy a large amount of space in the operating room and require the use of additional support personnel to operate such systems.
In view of the foregoing, a need exists for a surgical tool that can reduce the risk of damage to the anatomy in the vicinity of the surgical site, reduce the number of tools required to perform a surgical procedure, and enable a surgeon to perform the functions irrigation and/or debris removal without having to stop the cutting procedure and/or remove the cutting tool from the surgical site.
An aspect of the present invention relates to a surgical tool. The surgical tool includes a cutting element, a first portion configured to supply a fluid to a surgical site, and a second portion configured to apply a pressure to the surgical site. The first portion, second portion, and cutting element are integrated as a single component.
Another aspect of the present invention relates to a surgical tool. The surgical tool includes a cutting element mounted to a rotatable drive shaft and a tubular outer portion surrounding the cutting element and drive shaft. The outer tubular portion and the drive shaft are configured for relative rotational and axial movement relative to each other.
Yet another aspect of the present invention relates to a surgical method. The surgical method includes introducing a surgical tool to a surgical site, cutting a portion of a bone of a patient with the surgical tool, irrigating the surgical site with the surgical tool, and removing debris from the surgical site with the surgical too. The steps of cutting, irrication and removing debris may be performed simultaneously.
Yet another aspect of the present invention relates to a surgical tool. The surgical tool includes a hollow drive shaft, a motor configured to rotate the hollow drive shaft, a rotary cutting element disposed at one end of the hollow drive shaft, and a tubular outer element surrounding the hollow drive shaft and at least a portion of the rotary cutting element. The surgical tool also includes a bearing mechanism and a means for moving the hollow drive shaft and the tubular outer element axially relative to each other to move the rotary cutting element between a retracted position within the tubular outer element and an extended position in which the rotary cutting element extends beyond an end of the tubular outer element. The surgical tool further includes a source of irrigation fluid connected with the hollow drive shaft or the tubular outer element to supply irrigation fluid adjacent the rotary cutting element and a source of suction connected with the hollow drive shaft or the tubular outer element to withdraw fluids and bone chips from adjacent the rotary cutting element.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain principles of the invention.
Presently preferred embodiments of the invention are illustrated in the drawings. Although this specification refers primarily to cutting bone, it should be understood that the subject matter described herein is applicable to other parts of the body, such as, for example, soft tissue, ligaments, cartilage, organs, and muscles.
The cutting element 20 of the surgical tool 10 is configured to cut and/or sculpt an anatomy of a patient, such as bone or soft tissue. The cutting element 20 may include any conventional cutting element. For example, the cutting element 20 may comprise a blade or blades, a spherical burr, or the like and may include cutting surfaces on the bottom and/or the sides of the cutting element 20. The cutting element may be adapted to oscillate but is preferably a rotary cutting element as shown in
In one embodiment, the cutting element 20 is configured to be disposed within the outer portion 40 of the surgical tool 10 and to be controllably extended therefrom. For example, the cutting element 20 may be adapted to be axially moveable along an axis A-A between at least a first position and a second position, such as a retracted position (shown in
In the extended position (shown in
To enable the cutting element 20 to move axially along the axis A-A, the surgical tool 10 may include a means for axially displacing the cutting element 20, such as a mechanism 80 as shown in
In addition to cutting, the surgical tool 10 is configured to perform irrigation and vacuum (or debris removal) functions. For example, the surgical tool 10 may include a first portion configured to perform an irrigation function by supplying fluid to the surgical site to flush and lubricate the surgical site. The surgical tool 10 may also include a second portion configured to perform a vacuum function by applying a pressure (e.g., a negative or suction pressure) to the surgical site for removal of debris (e.g., bone chips, cutting debris, etc.) and fluid (e.g., flushing fluid, blood, etc.). The pressure applied by the second portion may also be a positive pressure, such as a flow of air to dry the surgical site. In one embodiment, the first portion (which supplies the fluid) may be the outer portion 40 of the surgical tool 10, and the second portion (which applies the pressure) may be the inner portion 30. To enable delivery of fluid and the application of pressure, both the inner portion 30 and the outer portion 40 are hollow. For example, the inner portion 30 may include a passage 60 (shown in
As shown in
Because the cutting element 20, the inner portion 30, and the outer portion 40 are integrated into a single component, the surgical tool 10 may be used for cutting, irrigation, and/or debris removal, which reduces the number of separate surgical tools required to perform a surgical cutting operation. Additionally, incorporating the functions of cutting, irrigation, and debris removal into a single tool (a) enables each of the functions to be performed independently (i.e., one function at a time) or in combination (i.e., two or more functions performed simultaneously) and (b) eliminates the need to change out surgical tools between functions. As a result, the time to perform a surgical cutting operation is reduced.
The surgical tool 10 includes at least one element configured to stabilize the cutting element 20 and/or the inner portion 30 on which the cutting element 20 is disposed. For example, the surgical tool 10 may include one or more stabilization elements disposed between the inner portion 30 and the outer portion 40. The number of stabilization elements depends on the design of the surgical tool 10. For example, as a length of the surgical tool 10 increases the number of stabilization elements needed will also increase. In one embodiment, as shown in
Each of the inner portion 30, the outer portion 40, and the spacers 50 may be made of any material suitable for use in a surgical instrument. Suitable materials include, for example, stainless steel, aluminum, titanium, and the like. In one embodiment, the outer portion 40 is made of a translucent material, such as a polycarbonate resin thermoplastic. Use of a translucent material is advantageous because the surgeon can see into the passage 70 to determine whether debris is clogging the passage 70 and/or the apertures 150 of the spacers 50a and 50b. In the event the passage 70 and/or the apertures 150 become clogged, the surgeon may use alternate cycles of suction and irrigation to unclog the passage 70 and/or the apertures 150.
The surgical tool 10 additionally includes irrigation and vacuum components. As is well known, the irrigation components may comprise irrigation lines 300 and an irrigation pump 350, and the vacuum components may comprise vacuum lines 400 and a vacuum pump 450. As shown in
The surgical tool 10 is adapted to be connected to a power source to provide power for the cutting element drive motor and the irrigation and vacuum pumps. The power source may be any known power source, such as, for example, an electrical outlet, a battery, a fuel cell, and/or a generator and may be connected to the surgical system 10 using conventional hardware (e.g., cords, cables, surge protectors, switches, battery backup/UPS, isolation transformer, etc.). The surgical tool 10 may also include additional components such as a controller and a user input device for controlling the cutting element 20, the irrigation components, and/or the vacuum components. For example, the user input device may be a foot pedal (or other switching device) that can be positioned on the floor of the operating room in proximity to the surgeon. Depressing the foot pedal causes the power source to supply power to the cutting element 20 (or to a compressed air supply in the case of a pneumatic cutting element), the irrigation pump, and/or the vacuum pump. Conversely, releasing the foot pedal disrupts the flow of power to the cutting element 20, the irrigation pump, and/or the vacuum pump.
To activate the surgical tool 10 for a cutting operation, the surgeon turns the surgical tool 10 ON (e.g., by depressing the foot pedal). In one embodiment, when the surgeon turns the surgical tool 10 ON, power is applied to the cutting element drive motor and to the mechanism 80 so that rotation of the cutting element 20 and extension of the cutting element 20 out of the outer portion 40 begin simultaneously. Alternatively, the rotation and extension may begin one after the other. To deactivate the surgical tool 10, the surgeon turns the surgical tool 10 OFF (e.g., by depressing the foot pedal). In one embodiment, when the surgeon turns the surgical tool 10 OFF, the cutting element 20 shuts off and begins retracting into the outer portion 40 of the surgical tool 10 simultaneously. Alternatively, the shut off and retraction may begin one after the other. One advantage of retracting the cutting element 20 at the same time the cutting element 20 is shut off is that even though the cutting element 20 may still be rotating (e.g., due to momentum), the cutting element 20 is effectively disabled because the sharp portions of the cutting element 20 are retracted and thus enclosed by the outer portion 40 so that there is no possibility of contact with the anatomy. Thus, the surgical tool 10 is in the safe configuration. As a result, the surgeon can irrigate the surgical site, remove debris from the surgical site, and/or withdraw the surgical tool 10 from the patient's body without fear of inadvertently contacting (and possibly damaging) the patient's anatomy with the cutting element 20.
In a preferred embodiment, shut off and/or retraction of the cutting element 20 is incorporated as an automatic safety feature of the surgical tool 10. For example, the surgical tool 10 may include a controller (as is well known) adapted to shut off the cutting element 20 (e.g., by disrupting a flow of power to surgical tool 10) in the event of a system fault or other adverse condition. In one embodiment, the cutting element 20 is an electric tool and includes a relay disposed along an electrical connection between the foot pedal (or other user input device) and the cutting element drive motor. The relay is closed under normal operating conditions so that the cutting element 20 is activated when the surgeon depresses the foot pedal. If a fault is detected, however, the controller commands the relay to open so that the cutting element 20 cannot be activated even if the surgeon depresses the foot pedal. In the case of a pneumatic cutting element 20, a pneumatic shutoff valve may be disposed in an air connection between the foot pedal and the cutting element drive motor. When the fault or other adverse condition is removed, the controller may issue a signal, such as a “fault cleared” signal, so that the surgeon may initiate operation of the cutting element 20 and resume the cutting procedure. The safety feature of the surgical tool 10 may also be activated by a surgical system with which the surgical tool 10 is being used, such as, for example, a robotic surgical system as disclosed in U.S. patent application Ser. No. 11/357,197, U.S. Pub. No. 2006/0142657, filed Feb. 21, 2006, and incorporated by reference herein in its entirety. In a preferred embodiment, the robotic surgical system is the HAPTIC GUIDANCE SYSTEM™ available from MAKO SURGICAL CORP.® in Ft. Lauderdale, Fla.
In addition to shutting off the cutting element 20, an additional precaution may include automatically moving the cutting element 20 into the retracted position when a system fault or other adverse condition is detected. As discussed above, retraction may be accomplished by activating the biasing element 85 which is configured to bias the cutting element 20 in the retracted position. When the cutting element 20 is retracted, the surgical tool 10 is in the safe configuration. Thus, the surgeon can safely withdraw the surgical tool 10 from the patient's body so that he can investigate and/or correct the system fault or other adverse condition. The surgical tool controller may be programmed to trigger a fault when an undesirable condition arises, such as, for example, a power failure or system problem (e.g., motor overheating or failure). During a surgical navigation procedure that incorporates a tracking system (e.g., an optical camera) to track objects (e.g., the surgical tool 10 and the anatomy), a fault may be triggered, for example, when the tracking system is unable to detect a tracked object (e.g., a tracking array is occluded with blood, a line of site between the camera and a tracking array is blocked, etc.), when the anatomy moves suddenly, and/or when the surgical tool 10 is in an undesirable location relative to the anatomy or a surgical plan. The surgical tool 10 may also include a failsafe configuration where positive activation (e.g., depressing a detent) is required to extend the cutting element 20 against the force of the biasing element 85. One advantage of the failsafe configuration is that the biasing element 85 will return the cutting element 20 to the retracted position even in the absence of a fault signal.
In operation, the surgical tool 10 may be used to perform a surgical cutting operation, to irrigate a surgical site, and/or to remove debris from the surgical site. The surgical tool 10 may be used for a variety of cutting operations but is especially useful for cutting bone. In particular, the surgical tool 10 can be manipulated to sculpt a desired shape into a surface of a bone. For example, the surgeon may operate the surgical tool 10 to prepare the bone to receive a prosthetic device, such as a joint implant. In one embodiment, the surgeon can prepare a femur F and a tibia T of a knee joint to receive components of a unicondylar knee implant 500 (shown in
According to one embodiment, as shown in
Alternatively, as opposed to pressing the rotating, extended cutting element 20 into the bone to make the independent cuts 1, 2, and 3, the surgeon may begin each independent cut with the cutting element 20 in the retracted position. In this embodiment, the surgeon (a) moves the surgical tool 10 to the first position and contacts the bone with the distal end of the outer portion 40, (b) activates the cutting element 20 so that the cutting element 20 is rotating, (c) extends the cutting element 20 from the outer portion 40 of the surgical tool 10 to the desired cutting depth to make the first cut 1, (d) retracts the cutting element 20 to the retracted position to withdraw the cutting element 20 from the first cut 1, (e) repositions the surgical tool 10 in the second position, and (f) repeats the procedure to form the remaining independent cuts. In another embodiment, the shape S may be formed by making one or more sweep cuts (as illustrated in
One advantage of the surgical tool 10 is that once the surgeon has cut the shape S in the bone, he can place a trial implant component on the prepared surface of the bone to test the fit of the particular implant he plans to implant in the joint. If the joint is too loose when the trial implant component is installed on the prepared bone surface, the shape S has been cut too deeply into the bone. The surgeon can correct the loose joint condition by implanting an implant having a greater thickness than the implant selected during surgical planning. For example, the surgeon can implant a tibial component 504 having a tibial insert that is thicker than the tibial component selected during surgical planning. Conversely, if the joint is too tight when the trial implant component is fitted on the prepared bone surface, the shape S is too shallow. Rather than selecting a new implant component, the surgeon can simply extend the cutting element 20 to a new cutting depth and recut the shape S. For example, if the original cutting depth was 1 mm and the joint is too tight, the surgeon can extend the cutting element to 1.5 mm, for example, and recut the shape S.
Thus, according to an embodiment, a surgical method for preparing a surface of a bone with the surgical tool 10 includes the following steps: (a) extending the cutting element 20 of the surgical tool 10 to a first selectable distance from the outer portion 40; (b) preparing the surface of the bone to receive an implant by removing a portion of the bone with the cutting element 20; (c) installing a trial implant component in the prepared surface of the bone; (d) analyzing the fit of the trial implant in the prepared surface of the bone; (e) removing the trial implant component from the surface of the prepared bone; (f) extending the cutting element 20 to a second selectable distance; and (g) recutting the prepared surface of the bone based on the analysis of the fit of the trial implant. Advantageously, while the surface of the bone is prepared to receive the implant, the outer portion 40 of the surgical tool 10 protects adjacent tissue from unintended impingement by the portion of the cutting element 20 enclosed within the outer portion 40.
The ability of the surgeon to incrementally extend the cutting element 20 is particularly useful when the surgical tool 10 is used in combination with a haptic robotic surgical system as disclosed in the above-referenced U.S. Pub. No. 2006/0142657. In a preferred embodiment, the robotic surgical system is the HAPTIC GUIDANCE SYSTEM™ available from MAKO SURGICAL CORP.® in Ft. Lauderdale, Fla. In this embodiment, as described in U.S. Pub. No. 2006/0142657, the surgeon uses surgical planning software to plan the placement of an implant on the patient's bone by positioning a virtual model of the implant on an image of the patient's bone. The planning software generates a virtual haptic object that defines a virtual cutting boundary (e.g., the desired shape S of the bone cut) corresponding the planned implant placement. During surgery, the image of the bone, the haptic object, and the surgical tool 10 are registered to the patient's physical anatomy, and the surgical tool 10 and the anatomy are tracked by a tracking system. As the surgeon manipulates the surgical tool 10 to sculpt the bone, the robotic surgical system provides haptic guidance to the surgeon to maintain the cutting element 20 of the surgical tool 10 within the virtual cutting boundary defined by the haptic object. After sculpting, a trial implant is fitted to the prepared surface of the bone. If a trial implant indicates that the joint is too tight (i.e., the cut is too shallow), the surgeon knows that he must make a deeper cut. Rather than replanning the placement of the implant component so that the planning software can generate a second haptic object defining a deeper virtual cutting boundary, the present invention advantageously enables the surgeon to simply extend the cutting element 20 of the surgical tool 10 to a new increment and recut the bone surface. As a result, the surgical procedure is simplified and the time required to perform the procedure is reduced.
The surgical tool 10 may be used in a variety of surgical procedures to perform a surgical cutting operation, to irrigate a surgical site, and/or to remove debris from the surgical site. One embodiment of a surgical method according to the present invention includes steps S1 to S4, as shown in
The steps of the surgical method may be performed in any order and may include additional steps. For example, in one embodiment, the surgical method includes one or more of the following steps: (a) extending the cutting element 20 from the outer portion 40 of the surgical tool 10; (b) extending the cutting element 20 to a selectable distance (e.g., the selectable distance D shown in
The surgical tool 10 may be used independently or in combination with existing surgical tools and systems, such as, for example, the robotic surgical system disclosed in the above-referenced U.S. Pub. No. 2006/0142657. In a preferred embodiment, the robotic surgical system is the HAPTIC GUIDANCE SYSTEM™ available from MAKO SURGICAL CORP.® in Ft. Lauderdale, Fla. Whether used alone or in combination with other surgical tools and systems, embodiments of the present invention can be advantageously configured to provide a surgical tool that can reduce the time and number of tools required to perform a surgical cutting operation and the risk of unintended impingement of a cutting element on a patient's anatomy.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.
This application claims priority from U.S. Provisional Patent Application Ser. No. 60/809,519, filed May 30, 2006, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60809519 | May 2006 | US |
