Patent Description:
A surgical instrument may be used during a procedure such as within a selected region of a subject's anatomy. The surgical instrument may be out of view of a user, such as below a tissue of a subject during a procedure. A user, therefore, may be required to remove an instrument to view the exact location of the instrument or the condition of a surgical site. Accordingly, a procedure may require intermittent application of a selected surgical instrument, such as a burr.

<CIT> and <CIT> disclose systems for determining a position of a working end of a driven instrument.

A driver may power an instrument, such as a burr or other resection or driven instrument during a selected procedure. The instrument may be removably connected to a driver, such as a powered tool handle. The powered tool handle may include a motor and a portion that is graspable by a user, such as surgeon.

In using the instrument during the procedure, the user may desire or select to navigate the instrument. In navigating the instrument, a tracked location of at least a portion of the instrument is determined. In tracking the instrument, a navigation system may determine and illustrate a position of the instrument relative to an image of the subject or patient for a selected period of time.

The tracking device may include selected portions that are interconnected or formed with the instrument. The instrument may include a working end, an elongated shaft, and a hub or connection portion to connect to the tool handle. The hub portion may incorporate various portions, such as the tracking device.

The invention is defined by claims <NUM> and <NUM>. Surgical methods are not claimed.

With initial reference to <FIG>, in a procedure a navigation system <NUM> may be used by a user <NUM> to perform a selected procedure. The navigation system <NUM> may include various components that assist in navigating a procedure including a selected tracking system. The tracking system may include various components or portions such as various localizers. Various localizers may include an optical tracking system and/or an electromagnetic tracking system that includes a Tracking Coil Array (TCA) localizer <NUM>. While the optical tracking system may be used in conjunction with or simultaneously with the TCA <NUM>, it is understood that only one tracking system may be used with the navigation system <NUM>. In various embodiments, therefore, both an optical localizer <NUM> and the TCA <NUM> may be used together or simultaneously for tracking one or more instrument, or only one. An instrument <NUM> may be tracked during a selected procedure, such as a navigated procedure with the navigation system <NUM>.

The TCA <NUM> may include one or more conductive coils <NUM> positioned relative to a subject <NUM> on which a procedure is performed. In various embodiments, a procedure may be performed on or near a head <NUM> of the subject <NUM>. As discussed in further detail herein, a subject tracking device or assembly <NUM> may be connected to the subject <NUM>, such as to the head <NUM> of the subject <NUM>. The tracking assembly <NUM> may also be referred to as a Dynamic Reference Frame (DRF) or a patient tracker.

With continuing reference to <FIG>, the navigation system <NUM> may include various features or elements as discussed below. Generally, the navigation system <NUM> may be used to determine or track a position of an instrument <NUM> in a volume. The position may include both a three dimensional X,Y,Z location and orientation. Orientation may include one or more degrees of freedom, such as three degrees of freedom. Thus, a total of at least six degrees of freedom may be determined for the position of the instrument <NUM>.

Tracking the position of the instrument <NUM> may assist the user <NUM> in determining a position of the instrument <NUM>, even if the instrument <NUM> is not directly viewable by the user <NUM>. Various procedures may block the view of the user <NUM>, such as performing a repair or assembling an inanimate system, such as a robotic system, assembling portions of an airframe or an automobile, or the like. Various other procedures may include a surgical procedure, such as performing a spinal procedure, neurological procedure, positioning a deep brain simulation probe, or other surgical procedures on a living subject. In various embodiments, for example, the living subject may be a human subject <NUM> and the procedure may be performed on the human subject <NUM>. It is understood, however, that the instrument <NUM> may be tracked and/or navigated relative to any subject for any appropriate procedure. Tracking or navigating an instrument for a procedure, such as a surgical procedure, on a human or living subject is merely exemplary.

Nevertheless, in various embodiments, the surgical navigation system <NUM>, as discussed further herein, may incorporate various portions or systems, such as those disclosed in <CIT>; <CIT>; and <CIT> and <CIT>. Various components that may be used with or as a component of the surgical navigation system <NUM> may include an imaging system <NUM> that is operable to image the subject <NUM>, such as an O-arm® imaging system, magnetic resonance imaging (MRI) system, computed tomography system, etc. A subject support <NUM> may be used to support or hold the subject <NUM> during imaging and/or during a procedure. The same or different supports may be used for different portions of a procedure.

Image data may be acquired during a surgical procedure or acquired prior to a surgical procedure for displaying an image <NUM> on a display device <NUM>. The instrument <NUM> may be tracked in a trackable volume or a navigational volume that is produced by the transmitter antenna or transmitting coil array <NUM> that is incorporated into the localizer <NUM>, as illustrated in <FIG>. The position of the instrument <NUM> may be tracked in the tracking volume relative to the subject <NUM> and then illustrated as an icon 16i with the display device <NUM>. In various embodiments, the icon 16i may be superimposed on the image <NUM> and/or adjacent to the image <NUM>. As discussed herein, the navigation system <NUM> may incorporate the display device <NUM> and operate to render and display the image <NUM>, from image data. Also, the determined the position of the instrument <NUM> may be performed and displayed with the display device <NUM>, such as the icon 16i.

With reference to <FIG>, the localizer <NUM> may be an electro-magnetic (EM) localizer that is operable to generate electro-magnetic fields with coils <NUM> of the transmitting coil array (TCA) <NUM> which is incorporated into the localizer <NUM>. The TCA <NUM> may include one or more coil groupings or arrays. In various embodiments, more than one group is included and each of the groupings may include three coils, also referred to as trios or triplets. The coils may be powered to generate or form an electro-magnetic field by driving current through the coils of the coil groupings. As the current is driven through the coils, the electro-magnetic fields generated will extend away from the coils <NUM> and form a navigation domain or volume <NUM>, such as encompassing all or a portion of a head <NUM>, spinal vertebrae, or other appropriate portion. The coils <NUM> may be powered through a TCA controller and/or power supply <NUM>.

The navigation domain or volume <NUM> generally defines a navigation space or patient space. As is generally understood in the art, the instrument <NUM>, such as a drill, lead, etc., may be tracked in the navigation domain relative to a patient or subject with an instrument tracking device <NUM>. For example, the instrument <NUM> may be freely moveable, such as by the user <NUM>, relative to the DRF <NUM> that is fixed relative to the subject <NUM>. Both the tracking devices <NUM>, <NUM> may include tracking or sensing coils (e.g. conductive material formed or placed in a coil) that senses and are used to measure a magnetic field strength, etc. Due to the tracking device <NUM> connected or associated with the instrument <NUM>, relative to the DRF <NUM>, the navigation system <NUM> may be used to determine the position of the instrument <NUM> relative to the DRF <NUM>.

The navigation volume or patient space may be registered to an image space of the patient and the icon 16i representing the instrument <NUM> may be illustrated at a navigated (e.g. determined) and tracked position with the display device <NUM>, such as superimposed on the image <NUM>. Registration of the patient space to the image space and determining a position of a tracking device, such as with the tracking device <NUM>, relative to a DRF, such as the DRF <NUM> may be performed as generally known in the art, including as disclosed in <CIT>; <CIT>; and <CIT>; and <CIT>.

The navigation system <NUM> may further include a navigation processor system <NUM>. The navigation processor system <NUM> may include the display device <NUM>, the localizer <NUM>, the TCA controller <NUM>, and other portions and/or connections thereto. For example, a wire connection may be provided between the TCA controller <NUM> and a navigation processing unit <NUM>. Further, the navigation processor system <NUM> may have one or more user control inputs, such as a keyboard <NUM>, and/or have additional inputs such as from communication with one or more memory systems <NUM>, either integrated or via a communication system. The navigation processor system <NUM>, according to various embodiments, may include those disclosed in <CIT>; <CIT>; and <CIT>; and <CIT>, and/or may also include the commercially available StealthStation® or Fusion™ surgical navigation systems sold by Medtronic Navigation, Inc. having a place of business in Louisville, CO. elongated tube <NUM> may include an internal and/or external portion, such as the tools sold with the StraightShot® M5 power handle, by Medtronic, Inc. , having a place of business in Minneapolis, Minnesota. In various embodiments, the shaft <NUM>, may be included as an elongated tube or a tubular shaft.

The instrument <NUM>, including the elongated tube <NUM>, may include an exterior wall having an interior cannula through which the working end <NUM> is powered, such as by an elongated shaft <NUM> to drive the working end <NUM>. As discussed further herein, the shaft <NUM> driving the working end <NUM> may connect with the motor <NUM> through a hub <NUM>. The hub <NUM> may engage a collet <NUM> to hold or fix the instrument <NUM> relative to the handle <NUM>.

In various embodiments, irrigation may be provided through the instrument <NUM>, such as through or by an irrigation barb <NUM>. It is understood that the irrigation barb <NUM> may be connected with an irrigation hose or tubing to provide irrigation through the instrument <NUM>. Further, suction may be drawn or pulled through the instrument <NUM>, and through the handle <NUM>, such as through a suction tube <NUM>. The suction tube <NUM> and an electrical connection line <NUM> may be connected to a console or controller, which may be incorporated with the TCA controller <NUM>. It is understood that the console or controller may be similar to the console Medtronic IPC ® power and control console or System, sold by Medtronic, Inc. Nevertheless the instrument <NUM> may be moved and powered by the handle <NUM> when operated by the user <NUM>.

In various embodiments, the tracking device <NUM> may be incorporated into or onto the hub <NUM>. With exemplary reference to <FIG>, the tracking device <NUM> may be incorporated onto the hub <NUM> of the instrument <NUM>. The hub <NUM> of the instrument <NUM>, as illustrated in <FIG>, may be connected to the tube <NUM> through which the shaft <NUM> of the bit or working end <NUM> passes. The shaft <NUM> extends through the hub <NUM> and may terminate and/or engage a tongue <NUM>. The tongue <NUM> may terminate and/or have a terminal end <NUM>. The terminal end <NUM> may have a keyed or engaging portion, such as an engaging wall <NUM> to engage an internal element in the handle <NUM>. For example, a shaft extending from the motor <NUM> may engage the engaging wall <NUM> of the tongue <NUM>. An interference between the shaft extending from the motor <NUM> and the engaging wall <NUM> may allow for transfer of forces from the motor <NUM> to the tongue <NUM>. As the tongue <NUM> is connected to the bit shaft <NUM>, the working end <NUM> may then rotate due to a force transferred through elongated tube <NUM> may include an internal and/or external portion, such as the tools sold with the StraightShot® M5 power handle, by Medtronic, Inc. , having a place of business in Minneapolis, Minnesota. In various embodiments, the shaft <NUM>, may be included as an elongated tube or a tubular shaft.

In various embodiments, the tracking device <NUM> may be incorporated into or onto the hub <NUM>. With exemplary reference to <FIG>, the tracking device <NUM> may be incorporated onto the hub <NUM> of the instrument <NUM>. The hub <NUM> of the instrument <NUM>, as illustrated in <FIG>, may be connected to the shaft <NUM> through which the shaft <NUM> of the bit or working end <NUM> passes. The shaft <NUM> extends through the hub <NUM> and may terminate and/or engage a tongue <NUM>. The tongue <NUM> may terminate and/or have a terminal end <NUM>. The terminal end <NUM> may have a keyed or engaging portion, such as an engaging wall <NUM> to engage an internal element in the handle <NUM>. For example, a shaft extending from the motor <NUM> may engage the engaging wall <NUM> of the tongue <NUM>. An interference between the shaft extending from the motor <NUM> and the engaging wall <NUM> may allow for transfer of forces from the motor <NUM> to the tongue <NUM>. As the tongue <NUM> is connected to the bit shaft <NUM>, the working end <NUM> may then rotate due to a force transferred through the tongue <NUM>. The shaft <NUM>, passing through the hub <NUM>, may allow for the hub <NUM> to be positioned or moveable relative to the handle <NUM> and carry various components, such as the tracking device <NUM> relative thereto.

Generally, the bit shaft <NUM>, working end <NUM>, tongue <NUM>, and hub <NUM> components are provided as a single assembly, such as from a supplier. Thus, the user <NUM> may connected the instrument <NUM> to the handle <NUM>, including the motor <NUM>, as a single action or assembly. Further, the instrument may be a single use or one time use instrument. This allows the instrument to be useable with the handle <NUM> for the procedure, including tracking of the isntrument16, while allowing ease or assembly and efficient sterile preparation and disposal.

The hub <NUM> is illustrated in greater detail in <FIG>, and <FIG> and discussed below. A detail view of the hub <NUM> is illustrated in <FIG>. Initially, the working end <NUM> and the associated shaft <NUM> may be formed of a selected material, such as a metal or metal alloy. In various embodiments, the shaft <NUM> of the instrument <NUM> may also be formed of a selected metal or metal alloy material. The hub <NUM> may be formed as a single member either with the shaft <NUM> or separate therefrom. For example, the hub <NUM> may be formed of a selected polymer material that may be over molded or injection molded onto the shaft <NUM>. It is understood, however, that the hub <NUM> may be formed separately from the shaft <NUM> and connected during assembly of the instrument <NUM>. Moreover, it is understood that the hub <NUM> may be formed of selected appropriate materials such as polymers, copolymers, metal alloys, selected bearing materials, combinations thereof, or the like.

The hub <NUM> generally extends from a proximal end <NUM> to a distal end <NUM>. The proximal end <NUM> and distal end <NUM> may further be terminal ends of the hub <NUM>. As illustrated in <FIG>, and discussed further herein, at least a portion of a distal portion, such as extending from the distal end <NUM> toward the proximal end <NUM>, may be a covering or encapsulation <NUM>. The encapsulation portion or member <NUM> may include a wrapping or shrink wrap formed over selected portions of the hub <NUM>, as discussed further herein. It is further understood that the cover <NUM> may a rigid member that is passed on to the hub <NUM>, such as over the shaft <NUM>. The tracking device <NUM>, even when covered, may have an external dimension (e.g. cross-sectional diameter) 56a that is less than or equal to an external dimension 106a of a portion of the handle near or adjacent to the hub <NUM> and/or external dimension 106a' of a chuck or instrument attachment. Thus, the hub <NUM> including the tracking device <NUM> may allow a large field of view and efficient operation of the instrument <NUM> and the handle <NUM>.

For example, positioned on and/or fixed to the hub <NUM> may be a plurality of tracking elements or members that form the tracking device <NUM>. The tracking elements may include a first tracking coil assembly <NUM>, a second tracking coil assembly <NUM>, and a third tracking member <NUM>. Each of the tracking members <NUM>, <NUM>, <NUM> may incorporate or form a portion of the tracking device <NUM>. For example, each of the member portions <NUM>, <NUM>, <NUM> may include a coil, such as a micro coil <NUM>, <NUM>, <NUM>, respectively. The coils <NUM> - <NUM> may be formed around an inner core or a magnetically permeable core and positioned relative to a contact member or support. The coils <NUM> - <NUM> may be formed of a selected wire or connective material of a selected diameter. For example, the coils are formed by winding around an air core or selected core and in selected ends. Each of the coils <NUM>-<NUM> may be placed or connected to a board, such as a printed circuit board <NUM>, <NUM>, <NUM>, respectively. The ends of the coils <NUM> - <NUM> may be mounted or fixed to selected conductive portions of the respective boards <NUM> - <NUM>.

With reference to <FIG>, the coil assembly <NUM> is illustrated in greater detail. The hub <NUM> may include various mounting or fitting portions. For example, and in accordance with the present claimed invention, a well or holding region <NUM> may be defined by walls. An end wall 169a, a proximal wall 169b, and one or more side walls 169c, 169d may extend from a surface of the hub <NUM>. The walls <NUM> may form or define the well to receive or hold the coil assembly <NUM> in a selected position, including location and orientation relative to the hub <NUM>. The well may assist in manufacturing such as that the coil assembly <NUM> is positioned in a selected and appropriate position for each hub <NUM>. Further, each of the coil assemblies may be placed in similar wells.

The coil <NUM> may include ends of the coiled wire that are mounted to the board <NUM>, such as to pads. The board <NUM> may include traces to additional pads <NUM>, <NUM>. The pads <NUM>, <NUM> on the board <NUM> allow for a connection, such as an efficient and repeatable connection, of the connector <NUM>. Again, one skilled in the art will understand that each coil assembly may include a similar assembly.

The coil and board assemblies may then be fixed to the hub <NUM> in a selected manner. For example, the coils may be respectively epoxied or adhered to the respective boards <NUM> - <NUM>. The epoxied assemblies may be adhered or epoxied to the hub <NUM>, such as into the well or pockets <NUM>. Generally, the member portions <NUM>, <NUM>, <NUM> generally have similar or identical dimensions and a generally rectangular shape having dimensions of about <NUM> millimeters (mm) to about <NUM> millimeters per side, where measurements may include a measurement and/or manufacturing tolerance of about <NUM> to about <NUM>. Exemplary dimensions may include about <NUM> by about <NUM>, about <NUM> by about <NUM>, about <NUM> by <NUM>, and about <NUM> by about <NUM>. Generally, the member portions may have an area of about <NUM><NUM>, including less than about <NUM><NUM>, less than about <NUM><NUM> and about less than about <NUM><NUM>.

Further, a connector or communication line <NUM> may have selected twisted pair wires leads for each of the boards, such as a first lead <NUM>, a second lead <NUM>, and a third lead <NUM>. Each of the respective leads <NUM> - <NUM> may also be fixed to the respective boards <NUM> - <NUM>. It is understood that the respective leads <NUM> - <NUM> and the terminal ends of the coils <NUM> - <NUM> may be soldered or selectively affixed to the respective boards <NUM> - <NUM>, as is generally understood in the art.

The leads may pass along the common connector line <NUM> to a proximal connector <NUM>. The connector <NUM> may include a physical connection <NUM> to a selected console or assembly, such as the TCA controller <NUM>. As discussed herein navigation or tracking information from the tracking device <NUM> may be transmitted along the common connector <NUM> to the connector <NUM> and the physical connection <NUM>.

In the connector <NUM>, in various embodiments, the physical connector <NUM> may include a selected memory and/or processor assembly <NUM>. The memory and/or processor assembly <NUM> may include information regarding the instrument <NUM> to which the hub <NUM> is affixed. Information may include a geometry, such as a geometric position of the working end relative to the tracking device. For example, the information may include a distance <NUM>, along an axis <NUM> of the instrument <NUM>, from the tracking device may be the information. In addition and/or alternatively thereto, the information may include an offset distance <NUM> from the axis <NUM> of the instrument <NUM> to a working terminal end plane or position <NUM> of the working end <NUM>.

Accordingly, the memory and/or processor assembly <NUM> may have calibrated a predetermined or known positions of the working end <NUM> relative to the tracking device <NUM> stored thereon. The stored information may be transferred to the navigation system <NUM> when the physical plug <NUM> has attached to the TCA controller <NUM>. In transmitting the information, such as with a signal from the memory and/or processor assembly <NUM> to the navigation processor system <NUM>, the processor system <NUM> is able to access or determine the calibrated position of the working end <NUM> relative to the tracking device <NUM>.

The hub <NUM> may further include other components such as a fixation portion or member <NUM> to assist in holding the single line <NUM> relative to the hub <NUM>. The fixation <NUM> may be a selected adhesive, wrapping, insulation wrapping, or the like. Further the hub <NUM> may include selected connection features, such as keyed or non-cylindrical features <NUM> which may include interference walls or facets. Further, the hub <NUM> may include an irrigation line connection, such as hose barb <NUM> to allow for a connection of an irrigation line to the hub <NUM>. In various embodiments, the irrigation line may be connected to the barb <NUM> to provide a delivery of fluid through the hub <NUM> and thereafter through the shaft <NUM> around the working end <NUM>. A suction may also be provided through a second inner cannula due to the suction line <NUM>, as discussed above.

To assist in tracking the instrument <NUM>, or portions thereof, the tracking device <NUM> includes the tracking members <NUM>, <NUM>, <NUM> that are selectively positioned on the hub <NUM>. For example, each of the respective coils <NUM> - <NUM> may be positioned at about <NUM> to about <NUM> degrees, including about <NUM> or exactly <NUM> degrees, around the axis <NUM> relative to one another. It is understood that the tracking members <NUM> - <NUM> may be selectively positioned for various purposes.

Each of the respective coils <NUM> - <NUM> may be orthogonally positioned relative to one another. The field generated by the TCA <NUM> may then be sensed by the coils <NUM>-<NUM> positioned on the hub <NUM>. That is the first coil <NUM> may sense a field that has a main axis that is substantially perpendicular to field sensed by the second coil <NUM> and the third coil <NUM>. To sense the field in the selected orientations, the respective coils <NUM> - <NUM> may be positioned on the respective boards <NUM> - <NUM> in a selected manner or each of them may be formed connectively and positioned at different orientations on the hub <NUM>. It is understood, by one skilled in the art, that the coils <NUM>-<NUM> may also generate respective fields (e.g. orthogonal to one another) that are sensed by the TCA <NUM> for tracking of the tracking device <NUM>.

During use of the navigation system <NUM>, such as when the user <NUM> is moving an instrument <NUM> relative to the subject <NUM>, the tracking device <NUM> may sense the field generated by the TCA <NUM>. As discussed above the sensed field may be used to determine a position of the instrument <NUM>, such as a position of the working end <NUM>, relative to the subject <NUM>. In various embodiments, the DRF <NUM> may be used in combination with the tracking device <NUM> to determine the relative positon of the instrument <NUM> relative to the subject <NUM>. Accordingly, as discussed above, the icon 16i may be illustrated on the display device <NUM> to illustrate the position of the instrument <NUM> relative to the subject <NUM>.

In having the tracking members <NUM> - <NUM> positioned at the respective locations on the hub <NUM>, such as orientated orthogonally to one another, a selected degrees of freedom may be determined regarding the position of the tracking device <NUM>. For example, six degrees of freedom may be determined including a three dimensional (e.g. x,y,z location) and orientation (e.g. three degrees of freedom). It is understood, however, that less than three of the tracking members may be used with the tracking device <NUM>. Thus, as the motor <NUM> powers (e.g. rotates) the shaft <NUM> of the instrument <NUM>, the position of the working end <NUM> may be determined and illustrated as the icon 16i. During operation of the instrument <NUM> (e.g. rotating and resecting) and moving the instrument <NUM> (e.g. toward and away from a surface) tracking of the tracking device <NUM> occurs.

Further, the dimension or position of the working end <NUM> relative to the tracking device <NUM> may be recalibrated or determined during a procedure. For example, the user <NUM> may position the working end <NUM> relative to the DRF <NUM> at a selected or known position. The navigation system <NUM> may then calibrate or determine the position of the working end <NUM> relative to the tracking device <NUM> by determining or tracking the DRF <NUM> and the tracking device <NUM>. The instrument <NUM> may then be connected to the handle <NUM>, if not already connected, and the navigation may proceed without a predetermined calibration or pre-known position of the working end <NUM> relative to the tracking device <NUM>.

Claim 1:
A system for determining a position of a working end of a driven instrument (<NUM>), comprising:
a tool member handle (<NUM>);
an elongated tubular member (<NUM>) having a cannula therein;
a hub (<NUM>) extending along a longitudinal axis and connected to the elongated tubular member; and
a tracking device (<NUM>) connected to the hub, the tracking device including a plurality of tracking members (<NUM>, <NUM>, <NUM>);
wherein the hub is configured to be connected to the tool motor handle (<NUM>) having a tool motor (<NUM>) to drive a shaft and characterized in that the tracking device has an external transverse dimension transverse to the longitudinal axis of the hub, less than at least an external cross-sectional dimension transverse to a longitudinal axis of a distal end of the tool motor handle;
wherein the hub includes a plurality of walls (<NUM>) extending from an external surface, the walls defining a plurality of recessed wells (<NUM>);
wherein each tracking member is held within a recessed well (<NUM>); and
wherein the elongated tubular member, the hub, the tracking device the shaft, and the working end are configured as an assembly and attached to the tool motor handle as a single unit.