Instrument calibration

Surgical instrument calibration methods, systems, and devices are provided that allow a virtual representation of a surgical instrument to be modified to adjust for any variations in a distal tip of a surgical instrument. For example, an instrument calibration system is provided that can have a surgical instrument, a calibration instrument, and a monitoring system. The surgical instrument can have a distal tip and an orientation element thereon, and the calibration instrument can have a pivot point thereon and a calibration reference element attached thereto. The monitoring system can be configured to record movement of the surgical instrument with respect to the calibration instrument when the tip of the surgical instrument is inserted into the pivot point of the calibration instrument, and to calculate a deviation of the tip of the surgical instrument from a predefined ideal tip based on the recorded movement.

FIELD

Surgical devices, systems, and methods are provided for performing instrument calibration on surgical instruments.

BACKGROUND

Computer and/or robotic-assisted surgery has allowed for more successful surgical outcomes by providing a variety of different benefits to a surgeon, such as improved visualization during surgery, guidance, better control over instruments, etc. For computer and/or robotic systems to provide assistance, navigation systems are used for tracking movements of surgical instruments during a procedure and providing a virtual representation of the instrument relative to a scan of the patient. Accurately tracking movements of the instruments and accurately representing the instruments in various virtual representation is important for the safety of the patient. As such prior to use, each instrument must be calibrated to ensure accurate measurements and accurate virtual representations. However, current methods present challenges, such as accurately modeling instruments.

Therefore, improved instrument calibration techniques are needed.

SUMMARY

Methods, devices, and systems are provided herein that allow an instrument to be calibrated such that a virtual representation of the instrument can be updated to accommodate for any distortions or bending that may occur at the distal tip over time, such as in instruments having a curved distal tip. In one aspect, an instrument calibration system is provided with a surgical instrument that has an elongate shaft with a proximal end and a distal end. The distal end has a distal-most tip while the proximal end has an orientation element fixed in an initial position thereon. The system also has a calibration instrument with a point thereon that is configured to receive the distal-most tip of the surgical instrument for pivoting thereabout. The calibration instrument also has a predefined geometric structure and a calibration reference element attached thereto. The system also has a monitoring system that is configured to record movement of the surgical instrument when the distal-most tip of the surgical instrument is positioned at the pivot point of the calibration instrument by recording a relative position of the orientation element to the calibration reference element. The monitoring system is configured to calculate a deviation of the distal-most tip of the surgical instrument from a predefined ideal distal-most tip based on the recorded movement of the orientation element of the surgical instrument, a predefined ideal instrument axis of the surgical instrument, and the predefined ideal distal-most tip of the surgical instrument, and the monitoring system is configured to modify a virtual representation of the surgical instrument on a display based on the calculated deviation.

The system can have numerous variations. For example, the distal end of the surgical instrument can be a curved tip. In another example, the distal end of the surgical instrument can have a cavity formed therein. In one example, the monitoring system can be configured to determine an initial orientation of the orientation element with respect to the surgical instrument while the orientation element remains in a fixed position relative to the surgical instrument. In another example, the monitoring system can be configured to determine an actual orientation of the surgical instrument in use while the orientation element on the proximal end thereof is moved to one of a plurality of second positions different than the initial position on the surgical instrument without requiring re-recording movement of the surgical instrument with respect to the calibration instrument.

In still another example, the pivot point on the calibration instrument can include a plurality of removable and replaceable pivot points, and each of the plurality of removable and replaceable pivot points can be configured to correspond to one of a plurality of different distal-most tips of a plurality of different surgical instruments. The monitoring system can also be configured to be updated depending on which one of the plurality of removable and replaceable pivot points is used.

In some embodiments, each of the orientation element and the calibration reference element can include one of an array having a plurality of trackable targets thereon, an electro-magnetic sensor, and a gyroscope. The monitoring system can also include at least one camera, at least one sensor, at least one processor, and at least one display. In some embodiments, the monitoring system can be part of a robotic surgery system, and the surgical instrument can be configured to be controlled by the robotic surgery system. Exemplary surgical instruments include, for example, a screwdriver and a discectomy device. In another embodiment, the orientation element can be configured to rotate about the surgical instrument in a plurality of known orientations, and the monitoring system can be configured to update a virtual representation of the surgical instrument on a display based on each of the plurality of known orientations of the orientation element without rerecording the relative position of the orientation element to the calibration reference element in each of the plurality of known orientations.

In another aspect, a method of calibrating a surgical instrument for use during surgical navigation is provided that includes inserting a distal-most tip on a distal end of the surgical instrument onto a pivot point on a calibration instrument while the calibration instrument has a predefined geometric structure and a calibration reference element attached thereto. The method also includes pivoting the surgical instrument about the pivot point such that a proximal end of the surgical instrument moves along an approximately circular path above the calibration instrument while a monitoring system records reference coordinate points of an orientation element fixed at a first position on the surgical instrument relative to reference coordinate points of the calibration reference element on the calibration instrument. The method further includes comparing, by the monitoring system, the recorded reference coordinate points to at least one stored reference coordinate point of an orientation element on a predefined ideal surgical instrument to calculate a deviation of the distal-most tip of the surgical instrument from a predefined ideal distal-most tip based on the comparison. After determining the deviation of the distal-most tip, the monitoring system modifies a virtual representation of the surgical instrument on a display based on the calculated deviation.

The method can have a number of variations. For example, the method can include determining by the monitoring system an initial orientation of the orientation element with respect to the surgical instrument while the orientation element remains in a fixed position relative to the surgical instrument.

In another embodiment, the pivot point can be formed on a removable portion of the calibration instrument, and the method can include replacing the removable portion of the calibration instrument with a second removable portion having a second pivot point with a different shape configured to match the distal-most tip of the surgical instrument. In some embodiments, the method can include updating the monitoring system based on the second pivot point.

In other aspects, the method can include, after modifying the virtual representation of the surgical instrument based on the calculated deviation, rotating the orientation element of the surgical instrument to a different known orientation and modifying by the monitoring system the virtual representation of the surgical instrument on the display based on the different known orientation of the orientation element.

In another aspect, a method for calibrating a surgical instrument with a distal-most tip is provided that includes recording, by a monitoring system, a movement of an orientation element at an initial position on the surgical instrument with respect to a calibration reference element on a calibration instrument. The method also includes calculating, by a processor operatively coupled to the monitoring system, a deviation of the distal-most tip of the surgical instrument from a predefined virtual representation of the distal-most tip of the surgical instrument by comparing the recorded movement of the orientation element of the surgical instrument to an expected movement of the orientation element. The predefined virtual representation of the distal-most tip of the surgical instrument includes a plurality of data points stored in a memory accessible by the processor that define a representation of the surgical instrument. The method also includes updating, by the processor, one or more first data points stored in the memory among the plurality of data points of the predefined virtual representation of the distal-most tip of the surgical instrument based on the calculated deviation of the distal-most tip.

Multiple variations of the method are possible. For example, the method can include controlling, by the processor, a surgical display so as to display the one or more updated first data points of the predefined virtual representation of the distal-most tip of the surgical instrument. In another example, the method can include, after updating the one or more first data points, determining, by the processor, an orientation of the surgical instrument during use when the orientation element thereon is moved to a second position different than the initial position on the surgical instrument without re-recording the movement of the surgical instrument with respect to the calibration instrument. In such an example, the method can also include updating, by the processor, one or more second data points stored in the memory among the plurality of data points of the predefined virtual representation of the distal-most tip of the surgical instrument based on the second position of the orientation element.

DETAILED DESCRIPTION

Various exemplary methods, devices, and systems are provided for performing instrument calibration on surgical instruments with curved distal tips. During computer and/or robotic-assisted surgery, an accurate virtual representation of any instrument being used during surgery is needed for the computer or robotic system to be able to correctly assess a current location of the instrument and to correctly provide assistance, guidance, etc. to the surgeon. Because virtual representations of instruments with curved distal tips can become inaccurate as a result of an actual distal tip on a corresponding surgical instrument bending or warping over time, updating a virtual representation of an instrument with a curved distal tip so that it accurately reflects a current distal tip geometry of the instrument can allow for better surgical results. For example, the virtual representation used by the computer or robotic system can accurately reflect the instrument used in the surgery rather than the system having to assume a distal tip is in an ideal state. Additionally, it can allow for reduced waste by eliminating the need to discard any surgical instrument that cannot be calibrated only because the curved distal tip is not in a perfect or near-perfect state while the instrument is otherwise surgically acceptable. Thus, instruments with curved tips can be accurately calibrated using the methods, devices, and systems provided herein such that a computer or robotic system can determine accurate distal tip geometry and measurements of the instruments, even after repeated use, and accurately update a virtual representation of the instrument.

Instrument calibration can be performed on a surgical instrument with a curved distal tip using a navigation array fixed on the surgical instrument in a first orientation. In certain embodiments, the navigation array can be rotated and/or moved into one or more different orientations on the surgical instrument during use to ensure the surgical instrument can be continually tracked by the computer or robotic system without requiring the surgical instrument to be recalibrated each time an orientation of the navigation array is changed. This movement allows the surgeon more flexibility in rotating or maneuvering the surgical instrument during use while saving time and still ensuring that the instrument is tracked by the system.

An exemplary instrument calibration system can include a surgical instrument with an elongate shaft that has a curved distal tip and an orientation array thereon. A calibration instrument can also be provided that has a predefined geometric structure and a calibration reference array attached thereto. A pivot point can be formed in the calibration instrument that is configured to receive the curved distal tip of the instrument. A monitoring system can also be provided that is configured to record coordinates of the surgical instrument when the curved distal tip of the surgical instrument is inserted into the pivot point of the calibration instrument and the instrument is rotated thereabout. Based on the recorded coordinates, the monitoring system can be configured to calculate a deviation of the curved distal tip of the surgical instrument from a predefined ideal curved tip and modify a virtual representation of the surgical instrument on a display based on the calculated deviation such that the virtual representation accurately mirrors the actual curved distal tip of the instrument with any bends or deviations reflected therein. Virtual representations can include a variety of different information and/or data representing parts of the instruments and systems discussed herein. For example, virtual representations can include pluralities of data points defining and/or representing shapes, orientations, locations, etc. of the various components of the systems discussed herein.

FIG.1illustrates one exemplary embodiment of a calibration instrument100with a pivot point110formed therein and a calibration reference array120attached thereon. The calibration instrument100is configured to allow calibration of a surgical instrument200with a curved distal tip210by a monitoring system300, discussed in detail below. The calibration instrument100has a predefined side and shape that is known to the monitoring system300, and the pivot point110is formed in one side102thereof.

The pivot point110is configured to receive the curved distal tip410of the surgical instrument200therein. The pivot point110can be sized and shaped to complement the curved distal tip210and to provide a relatively secure hold on a distal-most end212of the curved distal tip210to prevent the distal tip210from sliding around in the pivot point110. At the same time, the pivot point210provides a fixed point about which the surgical instrument200can smoothly rotate or pivot, as discussed more below. Thus, the pivot point110can be specifically configured to receive distal tips of certain instruments or groups of instruments, and dimensions of the pivot point110like depth of the cavity, diameter of the circular opening on the side wall102, angles of the sidewalls of the cavity, etc. can all be varied. For example, the pivot point110can be a cavity shaped like an inverse cone, as illustrated inFIG.2A, for receiving a cone-shaped or more rounded tip. However different embodiments can have different shaped pivot points depending on the type of distal end being received therein, such as cavities shaped like inverse cylinders, spheres pyramids, prisms, etc. While the pivot point110is formed in one side102of the calibration instrument100, it can be formed in various other locations on the calibration instrument100in other embodiments. Additionally, in some embodiments, the pivot point110can be removable and replaceable to allow different pivot points configured to accept different types of distal tips to be inserted and used during calibration of different types of instruments. For example,FIG.2Billustrates a removable pivot point mechanism152that can be inserted into and removed from a calibration instrument150that is similar to the instrument100, and the removable pivot point mechanism152can be secured in place through a variety of different means, such as through clips, engagements, friction, etc.

The calibration instrument100also has a calibration reference array120attached thereto that is configured to be tracked by the monitoring system300. The calibration reference array120has a predefined arrangement known to the monitoring system300such that it can provide a predefined 3-dimensional calibration coordinate system130to the monitoring system300during calibration. For example, as the instrument200is calibrated by pivoting the instrument200relative to the pivot point110, the calibration reference array120is configured to allow the monitoring system300to take images containing the calibration reference array120. Because the dimensional arrangement and orientation of the calibration reference array120with respect to itself and the calibration instrument100is predefined and known to the monitoring system300, the calibration reference array120allows the monitoring system300to use the calibration reference array120in each image as a reference scale to determine various orientation and measurement values of other objects in the images based on the position and visibility of the calibration reference array120in each image. This allows the monitoring system300to effectively place other objects in the images to scale within the context of the calibration coordinate system130.

The illustrated calibration reference array120has three targets122a,122b,122cthereon that can be imaged and tracked by the monitoring system300to provide a calibration coordinate system130to the monitoring system300and/or the control system400. The targets122a,122b,122care arranged in a generally triangular configuration in a single plane that extends parallel to and above an upper surface104of the calibration instrument100. Targets122a,122bare arranged on wings124,126that extend laterally away from each other on the upper surface104of the calibration instrument100. The calibration instrument100can be tipped sideways to rest on the wing126and maintain the calibration instrument100at a defined and consistent angle. During calibration, the pivot point110is thus accessible so that a distal tip of the instrument200can be inserted therein, as illustrated inFIGS.10-12. In other embodiments, however, the orientation and placement of the one or more target122a,122b,122ccan vary, such as being arranged in planar squares, rectangles, etc., or 3-dimensional cubes, pyramids, etc., and the wings124,126can be placed elsewhere on or removed entirely from the calibration instrument100. The calibration instrument100itself can also have various targets thereon, for example providing reference planes on one or more sides of the instrument100, along edges thereof, etc. While the calibration instrument100has a specific rectangular wing structure illustrated inFIG.1, in other embodiments, the calibration instrument can be any three-dimensional structure with one or more calibration reference elements thereon and one or more pivot points thereon.

While a variety of tracking approaches can be used, the targets122a,122b,122care configured to be captured in images and to provide orientation, location, and scale information based on their relative positions to each other in the images. For instance, if an image captures the targets122a,122b,122call in the triangular orientation visible by looking straight down on the calibration instrument100, the calibration instrument100is oriented such that the calibration reference array120is facing directly at the monitoring system200. If the targets122a,122b,122care captured such that all three targets are positioned along a shared line, the calibration instrument100is positioned such that the calibration reference array120is perpendicular to the monitoring system200. Thus, as the calibration instrument100moves three-dimensionally while the calibration reference array120is within view of the monitoring system300, the targets122a,122b,122callow the location, orientation, and scale within the image of the calibration instrument100to be determined by mapping the known and predetermined coordinates of the targets122a,122b,122crelative to each other to the actual coordinates of the targets122a,122b,122cin the captured images. A virtual representation of the calibration instrument100can thus be rotated and oriented so that the known and predefined orientations of the targets122a,122b,122con the virtual representation match up with the actual imaged targets122a,122b,122c. The virtual representation of the calibration instrument can be a plurality of coordinates defining the shape of the calibration instrument100and stored in a memory, as discussed below. Because the calibration reference array120is attached to the calibration instrument100in a known orientation and because the shape and size of the calibration instrument100is known, the location and pose of the calibration instrument can be accurately determined. Once the orientation of the calibration reference array120is determined, the relative distances between the targets122a,122b,122cin the actual image can be used for scale because the actual distances between the targets are known and predefined.

WhileFIG.1illustrates three targets122a,122b,122cin the form of spheres, any number of targets can be used, and the targets can take various different forms, such as flat images, grids, geometric shapes, patterns, various transmitting elements, lights, etc. The targets122a,122b,122care configured to be passive targets, however active targets can be used in some embodiments requiring one or more power sources, such as light-emitting diodes (LEDs), or a combination of active and passive tracking can be used. In other embodiments, one or more various different sensors can be used as reference elements instead of or in addition to one or more of the targets122a,122b,122cor instead of the calibration reference array120entirely, such as electro-magnetic sensor(s), gyroscope(s), various radio-frequency identification (RFID) tags or various transmitting tags, etc. The calibration reference array120and the calibration instrument100can be made from a variety of different materials, such as medical grade metals, plastics, polymers, ceramics, etc.

As indicated above, the pivot point110of the calibration instrument100is configured to receive a tip on a surgical instrument to allow a surgical instrument to be calibrated.FIGS.3and4illustrate one embodiment of a surgical instrument200that has an elongate shaft204extending from a handle202with a curved distal tip210on a distal end thereof. The surgical instrument200can be calibrated such that an accurate virtual representation of at least an axis of the elongate shaft204and the curved distal tip210can be generated by the monitoring system300. The virtual representation of the surgical instrument200can be a plurality of data points, e.g., coordinates, that aid in defining the shape of the surgical instrument200. The data points can be stored in a memory and updated in the memory based on the calculations discussed herein, as discussed in detail below.

The instrument200is configured to be calibrated through interaction with the calibration instrument100and the monitoring system300. Calibration can be achieved by comparing measured data to predetermined data based on a predefined or ideal instrument axis250and a predefined or ideal instrument tip252. The predefined instrument axis250and the predefined instrument tip252may not necessarily reflect a current configuration of the elongate shaft204and a distal-most end212of the instrument200. Rather, they can be calculated based on the design and/or manufacturing parameters for the instrument. For example, the predetermined data can be in the form of one or more coordinates representing ideal locations of one or more reference arrays on an ideal instrument. The coordinates, referred to as predetermined instrument coordinates, represent initial or expected data that can be provided to the monitoring system300to generate an initial or expected virtual representation of the instrument200. The initial or expected virtual representation can be used to calibrate a newly manufactured instrument and/or a used instrument. The predefined instrument axis250and the predefined instrument tip252can be specific to the type of instrument, and the values may be different when different instruments are used in other embodiments. While data representing the predefined instrument axis250and the predefined instrument tip252are provided to the monitoring system, a variety of other data can also be provided in some embodiments, such as instrument type, number of uses, etc.

By way of non-limiting example, the illustrated surgical instrument200is the DePuy Synthes Concorde Clear minimally invasive discectomy device, however a variety of instruments can be used, configured both for minimally-invasive or more traditional surgeries. The surgical instrument200can be made from a variety of different materials, such as medical grade metals, plastics, polymers, ceramics, etc. While the illustrated instrument200has a curved distal tip210, an instrument with a straight distal tip can be used in other embodiments, such as instruments with sharp or pointed distal tips, screwdrivers, etc.

Similar to the calibration instrument100, the surgical instrument200also has an orientation array220attached thereto that can be tracked by the monitoring system300and that has a predefined arrangement known to the monitoring system300such that it can provide predefined instruments coordinates within a predefined 3-dimensional instrument coordinate system230to the monitoring system300during calibration.

As the instrument200is calibrated by pivoting in the pivot point110, the orientation array220allows the monitoring system300to take images containing the orientation array220. Because the dimensional arrangement and orientation of the orientation array220is predefined and known to the monitoring system300, the orientation array220allows the monitoring system300to use the orientation array220in each image as a reference scale to determine various orientation and measurement values of other objects in the images based on the position and visibility of the orientation array220in each image, such as the surgical instrument200. Thus, the monitoring system300can effectively place other objects in the images to scale within the context of the instrument coordinate system230.

Similar to the calibration reference array120, in the illustrated embodiment the orientation array220has three targets222a,222b,222cthereon that can be imaged and tracked by the monitoring system300to provide the instrument coordinate system230in a similar manner to the targets122a,122b,122cof the calibration instrument100discussed above. The targets222a,222b,222care arranged in a generally triangular arrangement to one another in a single plane that extends parallel to and offset from a longitudinal axis of the surgical instrument200. The orientation array220is coupled to the surgical instrument200in a known and predefined orientation by an orientation arm224with a predefined length and an orientation ring226, however the orientation array220can be coupled to the instrument200in a variety of different ways.

Using the same imaging approach as the calibration reference array120, the surgical instrument200moves three-dimensionally while the orientation array220is within view of the monitoring system300. The targets222a,222b,222cthus allow the location, orientation, and scale within the image of the surgical instrument200to be determined by mapping the actual imaged coordinates of the targets222a,222b,222cin the captured images. The mapped coordinates of the targets222a,222b,222con the instrument200, referred to herein as the measured instrument coordinates, can be compared to the predetermined instrument coordinates calculated based on an ideal instrument. The system300can use these coordinates to generate a virtual representation of the surgical instrument200such that the measured instrument coordinates of the targets222a,222b,222con the virtual representation overlay the predetermined instrument coordinates of actual imaged targets222a,222b,222c. Because the orientation array220is attached to the surgical instrument200in a known orientation and because the shape and size of the surgical instrument200is known, the location and pose of the surgical instrument200with the curved distal tip210can then be determined. Once the orientation of the orientation array220is determined, the distances between the targets222a,222b,222cin the actual image can be used for scale because the actual distances between the targets are known and predefined.

There are three targets222a,222b,222cillustrated inFIGS.3and4, and the targets222a,222b,222care in the form of spheres. However, any number of targets can be used, and the targets can take various different forms, such as flat images, grids, geometric shapes, patterns, various transmitting elements, lights, etc. The targets222a,222b,222ccan be passive targets, however active targets can be used in some embodiments requiring one or more power sources, such as light-emitting diodes (LEDs), or a combination of active and passive tracking can be used. In other embodiments, one or more various different sensors can be used as orientation elements instead of or in addition to one or more of the targets222a,222b,222cor instead of the orientation array220entirely, such as electro-magnetic sensor(s), gyroscope(s), various radio-frequency identification (RFID) tags or various transmitting tags, etc. The orientation array220can be made from a variety of different materials, such as medical grade metals, plastics, polymers, ceramics, etc.

As noted, the calibration instrument100and/or the surgical instrument200can be tracked by a monitoring system, such as the monitoring system300illustrated inFIG.5. Specifically, the monitoring system300is configured to track an orientation and a location of the configuration reference array120and the orientation array220relative to the monitoring system300during calibration of the surgical instrument200, and it can be configured to track the surgical instrument200during use. For example, it is configured to track the targets122a,122b,122cof the calibration instrument100and the targets222a,222b,222cof the surgical instrument200, as discussed in detail above, and it can be configured to record movement of the surgical instrument200when the curved distal tip210of the surgical instrument200is inserted into the pivot point110of the calibration instrument100and rotated thereabout, as discussed in detail below. Based on the recorded movement, e.g., the recorded coordinates, the monitoring system300can be configured to calculate a deviation of the curved distal tip210of the surgical instrument200from the predefined instrument tip252. The monitoring system300can thus modify a virtual representation of the surgical instrument200on a surgical display, such as a virtual representation275of the surgical instrument200on a display500to be used during surgery on a patient10inFIG.5, based on the calculated deviation such that the virtual representation accurately mirrors the actual curved distal tip210of the instrument200with any bends or deviations reflected therein. As discussed in detail below, this can be achieved in part by translating the measured instrument coordinates and predetermined instrument coordinates in coordinate system230onto coordinate system130.

The monitoring system300can have a variety of configurations and can include various components, such as a navigation camera used for surgery. Depending on the type of target used, the monitoring system300can be configured to directly visualize the operating space through one or more cameras, and the monitoring system300can use active tracking, passive tracking, or some combination. It can also be part of a robotic surgical system, part of a computer-assisted surgical system, or a stand-alone device.

The control system or processor400is configured to assist in calculating the orientation and location of the arrays120,220relative to the monitoring system400based on data gathered by the monitoring system400. The control system400can be configured to calculate results both at a single point in time, periodically, or continuously over a period of time. The control system400can either be part of the monitoring system300, can be part of a robotic surgical system, can be a separate component, or some combination of the preceding. In some embodiments, it can also communicate with at least one of the monitoring system400, the calibration instrument100and/or the array120, the surgical instrument200and/or the array220, or some combination of the proceeding either directly or indirectly and either wirelessly or through wired connections.FIG.6illustrates a diagrammatic view of an exemplary device architecture of the control system400.

As shown inFIG.6, the control system400may contain multiple components, including, but not limited to, an internal processor (e.g., central processing unit (CPU)410), a memory420, a wired or wireless communication unit430, one or more input units440, and one or more output units450. It should be noted that the architecture depicted inFIG.6is simplified and provided merely for demonstration purposes. The architecture of the control system400can be modified in any suitable manner as would be understood by a person having ordinary skill in the art, in accordance with the present claims. Moreover, the components of the control system400themselves may be modified in any suitable manner as would be understood by a person having ordinary skill in the art, in accordance with the present claims. Therefore, the device architecture depicted inFIG.6should be treated as exemplary only and should not be treated as limiting the scope of the present disclosure.

The internal processor410is capable of controlling operation of the control system400and/or the monitoring system300depending on whether the control system400and the monitor system300are combined or separate. More specifically, the processor410may be operable to control and interact with multiple components associated with the control system400, as shown inFIG.6. For instance, the memory420can store program instructions that are executable by the internal processor410and data. The process described herein may be stored in the form of program instructions in the memory420for execution by the internal processor410. The communication unit430can allow the control system400to transmit data to and receive data from one or more external devices via a communication network. The input unit440can enable the control system400to receive input of various types, such as audio/visual input, user input, data input, and the like. To this end, the input unit440may be composed of multiple input devices for accepting input of various types, including, for instance, one or more cameras442(i.e., an imaging device), touch panel(s)444, microphone(s) (not shown), sensors446, one or more buttons or switches (not shown), and so forth. The input devices included in the input440may be manipulated by a user. Notably, the term image acquisition unit, as used herein, may refer to the camera442, but is not limited thereto. For example, the image acquisition unit can be the monitoring system300or a part thereof. The output unit450can display information on the display screen452for a user to view. The display screen452can also be configured to accept one or more inputs, such as a user tapping or pressing the screen452, through a variety of mechanisms known in the art, and the output unit450may further include a light source454. In some embodiments, the output unit450can be configured to send any processing results to various systems, such as a robotic surgical system or a computer-assisted surgical system. The control system400and/or the monitoring system300can also be configured to calculate orientations of instruments, distances, translations of coordinate systems, etc. based on information from the arrays120,220.

As noted above, interaction of the calibration instrument100, the surgical instrument200, the monitoring system300, and the control system400can allow the monitoring system300and/or the control system400to calculate a deviation of the curved distal tip210of the surgical instrument200, and to modify the virtual representation of the surgical instrument200on a surgical display based on the calculated deviation. As illustrated at step600inFIGS.7and8, initially, the monitoring system300and/or the control system400is provided with various known and predefined data as discussed above, such as a virtual representation of the surgical instrument200with the predefined instrument axis250, the predefined instrument tip252, and information regarding the orientation and arrangement of the orientation array220on the surgical instrument200, which can all be represented by a plurality of data points (e.g., predetermined instrument coordinates) defining the shape and orientation of the surgical instrument with the predefined shaft and tip; and a virtual representation of the calibration instrument100with a known shape and size and information regarding the orientation and arrangement of the calibration reference array120on the calibration instrument100, which can be represented by a plurality of data points defining the shape and orientation of the calibration instrument. This information can be provided through a variety of means, such as being manually inputted, automatically loaded by, for example, scanning or imaging one or more of the instruments100,200and/or the arrays120,220that can have identifying information thereon, downloaded onto the system300, etc. The monitoring system300is initiated to begin tracking the calibration instrument100and the surgical instrument200at step602, for example each instrument100,200and/or each array120,220can be displayed to the monitoring system300or the monitoring system300can be instructed manually to initiate tracking.

The curved distal tip210of the surgical instrument200is inserted into the pivot point110of the calibration instrument100at step604andFIG.9, for example by tipping the calibration instrument100at a defined angle as illustrated inFIGS.10-12and inserting the distal-most end212into the pivot point110. The surgical instrument200is rotated in an approximately circular motion above the calibration instrument, as illustrated inFIGS.10-12, and the monitoring system300records the movement of the orientation array220on the surgical instrument200relative to the fixed position of the calibration reference array120on the calibration instrument100. As the surgical instrument200moves, the distal-most end212of the curved distal tip210remains in the cavity of the pivot point110because the pivot point110is sized and shaped to secure the distal-most end212therein while allowing the surgical instrument200to smoothly rotate and pivot. The pivot point110thus provides a fixed, known point about which the surgical instrument200can rotate. The monitoring system300thus captures images and records coordinates of the orientation array220when the surgical instrument200is in a plurality of different poses or positions at step606. For example,FIGS.10-12illustrate exemplary rotation of the surgical instrument200while the monitoring system300captures a variety of images of the orientation array220in relation to the calibration reference array120. As such, the rotation generally defines a circular shape240of movement above the pivot point110that corresponds to a path of motion of the orientation array220.

The monitoring system300and/or the control system400can use the captured movement of the orientation array220(e.g. the measured instrument coordinates) in relation to the fixed pivot point110and the calibration reference array120to update the virtual representation of the surgical instrument200. The system(s)300/400can do this by comparing the captured calibration movement (e.g. the measured instrument coordinates) to expected calibration movement (e.g. predetermined instrument coordinates) of a model of the surgical instrument200with the predefined instrument axis250and the ideal tip252, discussed below.

The monitoring system300and/or the control system400can be initially provided with data representing a model of the surgical instrument200with the predefined instrument axis250and the ideal tip252. The system(s)300/400can also be provided with expected calibration movement data (e.g. predetermined instrument coordinates) of the surgical instrument200with the predefined instrument axis250and the ideal tip252. However, in some embodiments, the system(s)300/400can also model the expected behavior itself using the predefined instrument axis250and the ideal tip252data. With a new or ideal instrument, calibration movement data is modeled based on technical diagrams of the instrument. In other embodiments, though, it can be directly measured and recorded on a never-before-used instrument. Expected calibration movement data can be modeled by assuming the ideal instrument is rotated in a manner similar to the instrument200about a fixed point256. As such, a circle257of movement is defined above the fixed pivot point256, as illustrated inFIG.13A, that corresponds to a path of motion of an orientation array if the orientation array was fixed to the ideal instrument. For example, a plurality of points258can represent a plurality of coordinates of the ideal orientation array during calibration movement. The predefined instrument axis250defines a distance away from the fixed pivot point256at which the ideal orientation array would move, with each of the points258being positioned at the same distance away from the fixed point256. Thus, movement of the ideal surgical instrument about the pivot point256with the ideal tip252inserted therein can define a semi-sphere254with the predefined instrument axis250acting as a radius of the sphere254and the fixed point256representing both a center of the semi-sphere254and a location of a distal-most tip of the ideal surgical instrument. The semi-sphere254can thus represent calibration movement data (e.g. predetermined instrument coordinates) of an ideal surgical instrument with the predefined instrument axis250and the ideal tip252, and the center256of the semi-sphere can represent a location in 3-dimensional space of the distal-most end of the ideal tip252. While steps to actually create such a model are discussed above, in some embodiments the calibration movement data (e.g. predetermined instrument coordinates) can be provided initially such that no extensive modeling of an ideal surgical instrument is required.

Returning to the surgical instrument200, the circular shape240of movement of the surgical instrument200above the pivot point110represents similar motion to the circle257of movement above the fixed pivot point256that defines ideal or predefined motion of an ideal version of the surgical instrument. The circular shape240of movement of the surgical instrument200is defined by data points260captured by the monitoring system300of movement of the orientation array220. The points260illustrated inFIG.13Brepresent coordinates of movement of the orientation array220(and thus of the surgical instrument200) in 3-dimensional space with respect to the pivot point110during calibration. The data points260thus represent similar coordinates to the points258that define ideal orientation array movement during calibration. As such, the points260can be used to model virtual representations262of the elongate shaft204of the surgical instrument200in a plurality of poses corresponding to a plurality of poses of the elongate shaft204during actual pivoting, as illustrated inFIG.13C. The virtual representations262can be determined because they extend from the points260, which represent movement of the orientation array220of the instrument200, and they terminate in a common virtual distal tip264, which represents the curved distal tip210as it pivots in the pivot point110. During pivoting, the recorded points260are all at a same distance away from the pivot point110because an overall length of the elongate shaft204of the instrument200does not change during calibration. This is similar to the ideal surgical instrument in which the predefined instrument axis250defines a distance away from the fixed pivot point256at which the points258are positioned in the ideal instrument. The monitoring system300and/or the control system400can then mathematically match a semi-sphere266to the recorded points260, as illustrated inFIG.13Dand similar to the semi-sphere254of the ideal instrument. Movement of the actual surgical instrument200and recorded points260may not represent a perfect semi-sphere because measurements are being made in an actual operating setting and the curved distal tip210may be warped or bent. The semi-sphere266can thus be a best-fit sphere to the points260, and the predefined instrument axis250can be used as an initial sphere radius to help determine a sphere fit if needed. A center268of the semi-sphere266represents a location of the distal-most end212of the curved distal tip210because it was stationary in the pivot point110while the instrument200pivoted about that point. This is similar to the fixed point256representing both the center of the ideal semi-sphere254and the location of the distal-most tip of the ideal surgical instrument. The center268can thus correspond to the actual curved distal tip210with any warping or bending thereon.

The monitoring system300and/or the control system400can then map or transpose the semi-sphere266of the actual curved distal tip210onto the ideal semi-sphere254of the ideal tip252, as illustrated inFIG.13E. The system(s)300,400can compare the semi-spheres254,266to one another while placing the centers268,256of the semi-spheres254,266at a same or shared coordinate point. The centers268,256of the semi-spheres254,266can be placed at the same coordinate point because they represent the pivot point110and the fixed point256about which the surgical instrument200and the ideal surgical instrument were pivoted. If the semi-spheres254,266correspond perfectly relative to each other, then the system(s)300,400can determine that there is no warping or bending of the distal tip210from the ideal tip252because there is no deviation between the semi-spheres254,266. If there is any deviation between the two semi-spheres254,266, the monitoring system300and/or the control system400can determine that there is bending or warping in the distal tip210because calibration motion of the surgical instrument200does not correspond exactly to that of an instrument with the ideal tip252. Additionally, the amount of deviation can be determined because these spheres254,266are modeled in the same 3-dimensional coordinate system130. As such, any deviation of the measured semi-sphere266(representing the measured instrument coordinates) from the ideal semi-sphere254(representing the predetermined instrument coordinates) thus correlates to any bending or warping of the actual curved distal tip210from the ideal distal tip252. This correlated deviation can then be used to update the virtual model of the curved distal tip210to more accurately represent any bending or warping measured during calibration. As one illustrative example, the ideal semi-sphere254has a larger radius than the illustrated measured semi-sphere266inFIG.13E. As such, this deviation indicates that the curved distal tip210has been bent toward the orientation array220, which reduces a distance between the distal tip210and the orientation array220and thus causes a shorter or smaller radius of the measured semi-sphere266. Based on the amount of deviation between the radius of the ideal semi-sphere254and the radius of the measured semi-sphere266, the degree or amount by which the curved distal tip210has been bent toward the orientation array220can be determined. Once any deviation is calculated, the system(s)300,400can update the virtual model of the curved distal tip210so that it accurately represents the 3-dimensional location of its distal-most end212with any bending or warping at step608. The updated virtual model provides a more accurate representation of the surgical instrument200, providing better surgical results to a surgeon because the instrument200can be accurately represented while also not requiring disposal of a surgically-acceptable instrument because of minor bending. The updated virtual model can also be created through a single-step process of rotating the surgical instrument200in the pivot point110rather than any multi-stage process involving multiple measurements and calibration instruments.

The monitoring system300and/or the control system400can provide the updated virtual representation of the surgical instrument200with any warping of the curved distal tip210in step610to the surgeon and/or a surgical system through a variety of means, for example by being displayed on various displays for the surgeon, by being modeled as a virtual 3-dimensional image in real time, by being provided to a computer-assisted surgical system, by being provided to a robotic surgical system, etc. As illustrated inFIG.5, updating a virtual representation of the surgical instrument200with any warping of the curved distal tip210can thus include updating the virtual representation275of the surgical instrument200with the plurality of data points defining the shape and orientation of the surgical instrument200and the curved distal tip210by saving new values of the plurality of data points based on the calculated deviation to a memory, such as the memory420of the control system400. As noted above, the monitoring system300and/or the control system400can be directly incorporated into various computer-assisted surgical systems and/or robotic surgical systems in other embodiments. In some embodiments, the surgeon can then perform an operation, such as a minimally-invasive surgery, on a patient using the updated virtual representation275of the surgical instrument200. The calibration process discussed herein can be repeated as needed, and the predefined and/or ideal values discussed herein can represent either values from instruments that have not experienced any bending or warping or values from previously-performed calibration processes that represent some previous bending or warping but may need to be updated for continued accurate use.

FIGS.14-17Billustrate another embodiment of a surgical instrument700similar to the surgical instrument200with an elongate shaft704extending from a handle702and a curved distal tip710on a distal end of the elongate shaft704. Like surgical instrument200, surgical instrument700can be calibrated such that an accurate virtual representation of at least an axis of the elongate shaft704and the actual curved distal tip710can be generated that accurately reflects bends or distortions of the curved distal tip710and provided to a computer or robotic surgical system, such as the monitoring system300. The instrument700can be calibrated through interaction with the calibration instrument100and the monitoring system300.

The surgical instrument700has an orientation array720attached thereto, similar to array220, that can be tracked by the monitoring system300, similar to arrays120,220discussed in detail above, and to have a predefined arrangement known to the monitoring system300such that it can provide a predefined 3-dimensional instrument coordinate system, similar to the coordinate system230. However, while the orientation array220is configured to remain in one fixed orientation after calibration, the orientation array720can be rotated to a predefined plurality of different known orientations during use without requiring recalibration by the monitoring system300and the calibration instrument100. Because the plurality of different known orientations are provided to the monitoring system300during initial calibration, the monitoring system300and/or the control system400can be configured to determine an orientation and update a virtual representation of the surgical instrument700during use when the orientation array720is moved into a different one of the plurality of known orientations than the one used during initial calibration. The surgical instrument700can therefore be configured for use in a plurality of different orientations with the curved distal tip710being rotated as needed during surgery while being able to rotate the orientation array720to one of the plurality of different known orientations to ensure the orientation array720is still visible to the monitoring system300without blocking the view and without having to recalibrate the instrument700, as illustrated inFIGS.17A and17B. For example, the orientation array720has three targets722a,722b,722cthereon that can be imaged in a similar manner to the targets122a,122b,122cand the targets222a,222b,222c. The orientation array720is coupled to the surgical instrument700in one of four known and predefined orientations by engaging an array interface725at one end of an orientation arm724with a predefined length that has an orientation ring726disposed at an opposite end, as illustrated inFIG.15. The orientation ring726couples onto the instrument700through engagement with a ring coupling728disposed at a proximal end of the handle702, and as illustrated inFIG.16, the ring coupling728has a generally circular engagement surface730that is configured to interact with the ring coupling728of the orientation array720and has four notches732a,732b,732c,732dformed therein. The orientation ring726interacts with the four notches732a,732b,732c,732dsuch that the orientation ring726can engage with each notch in turn and remain in a temporarily-fixed orientation with respect to the surgical instrument700with respect to one of the notches732a,732b,732c,732d. For example, it can have four corresponding protuberances (not shown) on an inner surface of the orientation ring726that are configured to engage the four notches732a,732b,732c,732d. The ring726can also be opened by an engagement mechanism726aand a hinge726bsuch that the orientation ring726can be opened, rotated, and reengaged with the notches as desired. In use, the orientation ring726, and thus the orientation array720extending therefrom, can engage with the notch732aduring calibration and initial use such that the orientation array720is visible to the monitoring system300, as illustrated inFIG.17A. However, during use, the orientation ring726can be disengaged from the notch732aand rotated 180 degrees about the elongate shaft704of the surgical instrument700and to reengage the ring coupling728at the notch732c, thus rotating the orientation array720coupled thereto around to an opposite side of the surgical instrument700during use, as illustrated inFIG.17B. Because of this rotation, the curved distal tip710of the surgical instrument700can be applied to a different boney structure in a patient while the orientation array720can remain visible to the monitoring system300to allow continued tracking. While four notches732a,732b,732c,732dare illustrated herein, any number and type of engagement point is possible to allow an orientation array to be rotated to a predefined plurality of different known orientations.

Calibration of the instrument700is performed through the same process as instrument200discussed above, which involves rotation in the pivot point110of the calibration instrument100and tracking of the monitoring system300to generate an accurate virtual representation of the surgical instrument700and the curved distal tip710. However, monitoring system300and/or the control system400is provided with the predefined plurality of different known orientations of the orientation array720, such as four in the illustrated embodiment, and each orientation is uniquely identified, such as orientations in notches732a,732b,732c,732d. As the orientation is changed during use, as illustrated inFIGS.17A and17Bwhen the instrument700is used on vertebra of the patient10, the monitoring system300and/or the control system400is provided with the unique identifier of the new orientation so that the monitoring system300and/or the control system400can determine a new location and pose of the surgical instrument700and its curved distal tip710based on the new designated orientation, such as when the orientation array720is moved from the orientation in notch732ainFIG.17Ato the orientation in notch732cinFIG.17B. Because the monitoring system300and/or the control system400knows the fixed orientations at notches732a,732b, the monitoring system300and/or the control system400can update a virtual representation of the overall orientation or pose of the surgical instrument700without having to recalibrate the instrument700, for example by updating a plurality of data points of the virtual representation defining the surgical instrument700. After changing the orientation of the orientation array720, the identity of the new designated orientation can be provided to the monitoring system300and/or the control system400during use in a variety of ways. For example, the instrument700can have various markings, flags, sensors, engagements, patterns, etc. on the handle702, the shaft704, the orientation ring726, the ring coupling728, etc. that can either electronically or visually indicate to the monitoring system300and/or the control system400the change. The information can also be input to the monitoring system300and/or the control system400manually, such as by the surgeon or an assistant.

While instruments with protruding distal-most tips have been illustrated, in other embodiments, instruments having a cavity or void at a distal end thereof can also be calibrated with a calibration instrument having a protuberance, cone, sphere, etc. for using the same method as discussed above.FIGS.18-20illustrate a surgical instrument800similar to instruments200,700. The surgical instrument800has an elongate shaft804extending from a handle802and a straight distal tip810having a cavity810adefined therein on a distal end of the elongate shaft804. The cavity810ais in the shape of an inverse cone, however a variety of different instruments with different cavities can be used, such as oval, semi-spherical, cylindrical, curved, etc. The surgical instrument800has an orientation array820attached thereto, similar to arrays220,720, that can be tracked by the monitoring system300. Thus, surgical instrument800can be calibrated similar to surgical instruments200,700such that an accurate virtual representation of at least an axis of the elongate shaft804and the actual distal tip810can be generated that accurately reflects any bends or distortions of the distal tip810and can be provided to a computer or robotic surgical system, such as the monitoring system300.

Furthermore, the instrument800can be calibrated through interaction with a calibration instrument900, similar to calibration instrument100. The calibration instrument900has a calibration reference array920thereon, similar to array110, that can be tracked by the monitoring system300. The instrument900also has a pivot point910, similar to pivot point110, about which the instrument800can be pivoted and rotated for calibration, similar to the calibration process discussed above. The pivot point910protrudes from an upper surface of the calibration instrument900and is in the shape of a cone that is inserted into the cavity810aof the distal tip810on the instrument800, as illustrated by the arrow inFIG.19. However, any protruding shape can be used to correspond to a particular cavity on a surgical instrument to be calibrated, such as semi-spheres, cylinders, prisms, etc. Once the distal tip810of the surgical instrument800is engaged with the calibration instrument900, the instrument800is rotated thereabout for calibration, as illustrated by the arrow inFIG.20and similar to the process discussed above.

All of the devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the devices can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the devices, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the devices can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the devices can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application.

It is preferred that devices disclosed herein be sterilized before use. This can be done by any number of ways known to those skilled in the art including beta or gamma radiation, ethylene oxide, steam, and a liquid bath (e.g., cold soak). An exemplary embodiment of sterilizing a device including internal circuitry is described in more detail in U.S. Pat. Pub. No. 2009/0202387 filed Feb. 8, 2008 and entitled “System And Method Of Sterilizing An Implantable Medical Device.” It is preferred that device, if implanted, is hermetically sealed. This can be done by any number of ways known to those skilled in the art.

Additionally, it is understood that one or more of the systems and methods herein, or aspects thereof, may be executed by at least one processor. The processor may be implemented in various devices, as described herein. A memory configured to store program instructions may also be implemented in the device(s), in which case the processor can be specifically programmed to execute the stored program instructions to perform one or more processes, which are described further herein. Moreover, it is understood that the methods may be executed by a specially designed device, a mobile device, a computing device, etc., comprising the processor, in conjunction with one or more additional components, as described in detail herein.

Furthermore, the systems and methods, or aspects thereof, of the present disclosure may be embodied as non-transitory computer readable media on a computer readable medium containing executable program instructions executed by the processor. Examples of the computer readable mediums include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards, and optical data storage devices. The computer readable recording medium can also be distributed in network-coupled computer systems so that the computer readable media is stored and executed in a distributed fashion, for example by a cloud-based system, a telematics server, a Controller Area Network (CAN), etc.

One skilled in the art will appreciate further features and advantages of the described devices and methods based on the above-described embodiments. Accordingly, the present disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.