Patent Description:
Many different surgical procedures utilize some form of surgical navigation or tracking to aid in positioning surgical instruments relative to portions of patient anatomy during a surgical procedure. In spinal surgery, for example, a surgical navigation system can be used during disc removal, bone drilling, implant insertion, e.g., screw and/or cage insertion, and other steps of the surgery. Surgical navigation can help surgeons avoid delicate neural or vascular structures when moving instruments at a surgical site. In a robotic or robot-assisted surgical procedure, surgical navigation can be important to correctly position a robotically controller or assisted surgical instrument relative to a patient.

There are a number of known surgical navigation or tracking technologies, including optical navigation or tracking systems that utilize, e.g., stereoscopic sensors to detect infra-red (IR) light reflected or emitted from one or more optical markers affixed to surgical instruments and/or portions of a patient's anatomy. By way of further example, a tracker having a unique constellation or geometric arrangement of reflective elements can be coupled to a surgical instrument or portion of patient anatomy and, once detected by stereoscopic sensors, the relative arrangement of the elements in the sensors' field of view, in combination with the known geometric arrangement of the elements, can allow the system to determine a three-dimensional position and orientation of the tracker and, as a result, the instrument or anatomy to which the tracker is coupled. The surgical navigation system can establish one or more coordinate frames based on different markers or reference points in relation to patient anatomy and/or landmarks in the operating environment (e.g., a surgical table, etc.), such that the surgical navigation system can track a position and orientation of the patient anatomy.

These systems, however, are not without drawbacks. One issue encountered with optical navigation or tracking systems is that one or more markers used to establish a patient reference frame are often removed from a location of the surgical site, e.g., to avoid crowding the surgical space, to prevent unintended jostling of the marker during surgery, etc. With continued reference to spinal procedures, for example, a surgical site may be located at a first vertebral level and a marker for establishing a patient reference frame may be coupled to bony structure several vertebral levels removed from the surgical site. As such, movement of patient anatomy at the surgical site, e.g., the vertebral body, may go undetected or unregistered by the optical navigation or tracking system. In other words, a position and/or orientation of patient anatomy at the surgical site runs the risk of being inaccurately reflected in the navigation or tracking system. This can lead to undesirable results, such as inaccurate or imprecise guiding of surgical instruments and/or surgical robot components, increased risk of skiving the patient anatomy at the surgical site, and misinformation communicated to a surgeon or other user regarding the surgical landscape. <CIT> is directed to an apparatus for use in a transluminal procedure. The apparatus comprising, for example, a housing having a guide lumen and a seal proximal to a distal end of the housing that extends across and completely seals the guide lumen; a fixation element in the housing and adapted to secure the distal end of the housing to tissue; and a channel extending through the side wall of the housing having an outlet in communication with the lumen distal of the seal. Methods are also provided. A method includes, performing a transluminal procedure by: securing a datum and position indicator to a wall of a target lumen; forming an opening in the wall; advancing an instrument through the opening; and tracking the advancement of the instrument using the datum and position indicator. <CIT> teaches individual tools, where each tool is uniquely configured to perform a step or a portion of a step in a procedure associated with the implantation of a stabilizing device for stabilizing at least one spinal motion segment. The tools are usable individually, or more preferably as a tooling system in which the tools are collectively employed to implant an interspinous spacer, generally in a minimally invasive manner. Each of the tools is arranged with coordinated markings and/or other features to ensure consistent depths of insertion, proper orientation of the tools with respect to each other or an anatomical feature of the patient, and precise delivery of the spacer to maintain safe positioning throughout the implantation
<CIT> relates to methods and an apparatus for detecting or predicting surgical tool-bone skiving. The surgical tool is movably and/or snugly disposed within a guide-sleeve. A magnitude of a lateral force between the surgical tool and the guide-sleeve is measured. The present or future skiving is then detected or predicted according to the magnitude of the lateral force. An alert signal is generated in response to the detecting or predicting of the skiving. <CIT> relates to devices, systems, and methods for detecting unexpected movement of a surgical instrument during a robot-assisted surgical procedure. The surgical robot system may be configured to measure forces and torques experienced by the surgical instrument during the surgical procedure and determine if the forces and torques are within an acceptable range. The robot system is further configured to notify the user of the presence of the unexpected movement.

Accordingly, there is a need for improved systems, and devices that can monitor localized movement of patient anatomy at a surgical site and identify when such localized movement fails to be captured by a navigation or tracking system.

Surgical systems, and devices are disclosed herein that can detect movement of an anatomic structure at a surgical site relative to a cannula or instrument inserted into the surgical site, i.e., "localized" movement. The anatomic structure can be a bony anatomy that is not directly tracked by a global navigation system. For example, the anatomic structure can be a vertebral body that is one or more levels removed from a vertebral body or other structure to which a navigation marker is attached for monitoring by a global navigation system. In some embodiments, the present disclosure can determine whether detected localized movement of the anatomic structure is captured by a global navigation system. In this manner, the present disclosure can identify when placement and/or positioning of the anatomic structure at the surgical site may be inaccurately represented in the global navigation system, e.g., due to movement of the anatomic structure that may be minor or slight in nature. By capturing and alerting a user to such occurrences, remedial action can be taken to align the global navigation system and placement of the anatomic structure at the surgical site such that accurate navigation can be maintained, and a risk of skiving can be reduced. Additionally, or alternatively, embodiments of the present disclosure can detect localized movement of the anatomic structure and determine whether the detected localized movement exceeds a threshold condition. Accordingly, features of the present disclosure can be advantageously used in a variety of surgical procedures, e.g., with or without a global navigation system, minimally invasive procedures, robotic surgical procedures, robot-assisted surgical procedures, etc., to detect movement of patient anatomy at a surgical site that could otherwise go undetected and increase a risk of inaccurate navigation and/or skiving.

In one aspect, a surgical system includes a robot arm, a cannula coupled to the robot arm, a localized navigation sensor, and a controller. The localized navigation sensor is coupled to a distal end of the cannula and configured to detect movement of an anatomic structure relative to the cannula. The controller is configured to receive data from the localized navigation sensor and receive data from a global navigation system that tracks a location of a navigation marker located remotely from the anatomic structure. Further, the controller is configured to determine if movement of the anatomic structure detected by the localized navigation sensor is tracked by the global navigation system.

The localized navigation sensor can extend from the distal end of the cannula and, in some embodiments, can include at least one tine configured to extend from the distal end of the cannula. The controller can further be configured to determine movement of the anatomic structure based on a change in one or more of a geometry of the at least one tine and a location of the at least one tine. In some embodiments, the localized navigation sensor can include a plurality of tines configured to extend distally from the distal end of the cannula. In other embodiments, the localized navigation sensor can include at least one tine configured to extend radially from the distal end of the cannula.

The localized navigation sensor can include at least one of the following: a piezoelectric actuator, piezoelectric sensor, an ultrasound sensor, an electromagnetic sensor, a laser, a resistance-based sensor, a strain gauge. In some embodiments, the localized navigation sensor can be configured to detect a magnitude and a direction of localized movement of the anatomic structure. The anatomic structure can be a vertebral body.

Further described but not part of the present invention is a method, which includes positioning a cannula relative to an anatomic structure using a robot arm, detected movement of the anatomic structure relative to the cannula using a localized navigation sensor coupled to a distal end of the cannula, and determining if movement of the anatomic structure detected by the localized navigation sensor is tracked by a global navigation system that tracks a location of a navigation marker located remotely from the anatomic structure.

In some embodiments, the localized navigation sensor can include at least one tine and the method can further include extending the at least one tine from the distal end of the cannula to contact the anatomic structure. Detecting the movement of the anatomic structure can further include measuring at least one of a deformation in the tine or a change in location of the tine. In some embodiments, the method can include determining if movement of the anatomic structure exceeds a threshold amount of movement. The anatomic structure can be a vertebral body. In some embodiments, the method can further include alerting a user when the movement of the anatomic structure is not tracked by the global navigation system.

Further described but not part of the claimed invention is a surgical instrument, which includes a cannula and at least one sensor. The cannula has a proximal end and a distal end, the distal end configured for placement in proximity to an anatomic structure. The at least one sensor is configured to extend from the distal end of the cannula to contact the anatomic structure and measure localized movement of the anatomic structure relative to the cannula based on deformation of the at least one sensor.

The at least one sensor can include at least one tine configured to extend from the distal end of the cannula and, in some embodiments, the at least one tine can be configured to extend radially outward from the distal end of the cannula. In other embodiments, the at least one tine can include a plurality of tines configured to extend distally from the distal end of the cannula. The plurality of tines can be located circumferentially around the distal end of t cannula.

Any of the features or variations described above can be applied to any particular aspect or embodiment of the present disclosure in a number of different combinations. The absence of explicit recitation of any particular combination is due solely to the avoidance of repetition in this summary.

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices, and systems disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. The devices, and systems specifically described herein and illustrated in the accompanying drawings are non-limiting embodiments. The features illustrated or described in connection with one embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure.

Additionally, to the extent that linear or circular dimensions are used in the description of the disclosed devices, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such devices. Equivalents to such linear and circular dimensions can be determined for different geometric shapes. Further, sizes and shapes of the devices, and the components thereof, can depend at least on the anatomy of the subject in which the devices will be used, the size and shape of objects with which the devices will be used, and procedures in which the devices will be used. To the extent features, sides, components, steps, or the like are described as being "first," "second," "third," etc. such numerical ordering is generally arbitrary, and thus such numbering can be interchangeable.

Localized movement detection systems and related methods are disclosed herein that can track localized movement of an anatomic structure and can alert a user when the detected localized movement goes unrecognized by a global navigation system and/or when the detected localized movement exceeds a threshold condition. Alerting a user to either or both such instances can identify movement of patient anatomy at the surgical site that could otherwise go undetected and negatively impact a surgical procedure, e.g., due to an increased skiving risk as a result of shifted patient anatomy, inaccuracies in a global navigation system coordinate frame, etc. Localized movement detection systems of the present disclosure can include a localized navigation sensor coupled to a cannula, or other surgical instrument, that can be advanced at a surgical site such that the cannula is in contact with, or adjacent to, an anatomic structure of the patient. The localized navigation sensor can detect and measure movement of the patient anatomy relative to the cannula. More particularly, the localized navigation sensor can collect and transmit data to a controller that can be used to identify movement of the anatomic structure relative to the cannula. In some embodiments, the controller can identify a magnitude and/or direction of the detected localized movement and can decouple the data to identify the mode(s) in which such movement occurs. As noted above, in some embodiments, localized motion detection systems of the present disclosures can be used in connection with a global navigation system and can alert a user when the localized movement detected by the localized navigation sensor is undetected or unregistered by the global navigation system, however features of the systems disclosed herein can be advantageously utilized independently of a global navigation system. Moreover, the localized movement detection systems can be used during a procedure carried out by a surgical robot, a procedure carried out by a user, e.g., a surgeon, with some degree of robotic assistance, or in a procedure without involvement of surgical robots or robotic assistance.

<FIG> illustrates one embodiment of a surgical system <NUM> of the present disclosure that can detect localized movement of an anatomic structure at a surgical site. The system <NUM> can include a cannula <NUM> with a localized navigation sensor coupled thereto (not shown in <FIG>, but better seen in subsequent figures and described in connection with the same, e.g., the localized navigation sensor <NUM> of <FIG>). The cannula <NUM> can be advanced into a surgical site <NUM> such that a distal end 102d of the cannula is placed in contact with, or adjacent to, an anatomic structure, e.g., a vertebral body <NUM>. With the cannula <NUM> in such a position, the localized navigation sensor can detect movement of the vertebral body <NUM> relative to the cannula <NUM>. Relative movement between the vertebral body <NUM> and the cannula <NUM> can be referred to herein as "localized movement. " In some embodiments, a proximal end 102p of the cannula <NUM> can be coupled to a robotic device, e.g., a robot arm <NUM> that can navigate the cannula and/or hold the cannula steady.

Localized navigation sensors of the present disclosure can collect data during a surgical procedure while the distal end 102d of the cannula <NUM> is in proximity to the vertebral body <NUM> that can be analyzed to detect localized movement of the anatomic structure (such data may be generally referred to herein as "sensory data"). The localized navigation sensor can transmit sensory data to a controller <NUM>, which, in the illustrated embodiment of <FIG> can be included in a control unit cart <NUM> of the robot arm <NUM>. The controller <NUM> can also receive data from a global navigation system that can include a stereoscopic sensor <NUM> and at least one reference marker <NUM>. The reference marker <NUM> can consist of one or more tracking elements, e.g., reflective or active markers, and can be coupled to patient anatomy at a location remote from the surgical site <NUM> and, more particularly, removed from the vertebra <NUM> at the surgical site. For example, the marker <NUM> can be coupled to a vertebra <NUM> located one or more levels away from the surgical site <NUM>. The stereoscopic sensor <NUM> can detect light reflected off of the reference marker <NUM> (e.g., reflected infra-red light in some embodiments) and can transmit data to the controller <NUM>, which can utilize known fixed geometric positions of the tracking elements of the reference marker <NUM> and the detected positions of the tracking elements to determine a precise three-dimensional position and orientation of the reference marker <NUM> and thus the patient anatomy coupled thereto. In some embodiments, the global navigation system can include a second reference marker (not shown) that can, for example, be coupled to the control unit cart <NUM>, robotic arm <NUM>, or an end effector coupled to the robotic arm to locate the position of the cart and/or robot arm.

Data can be transmitted between components (e.g., the localized navigation sensor, the global navigation system, the robot arm <NUM>, the controller <NUM>, etc.) via any suitable connection, e.g., with wires (see <FIG>) or wirelessly using a low latency transfer protocol. The controller <NUM> can carry out real-time control algorithms at a reasonably high frequency with low additional latency, e.g., to analyze data received from the localized navigation sensor, communicate data to a user, coordinate movement of the robotic arm <NUM>, etc. As referenced above, the controller <NUM> can establish a global coordinate system based on information received from the global navigation system. More particularly, a position of the reference marker <NUM> can be used to track a position of the vertebra <NUM> to which it is coupled, which can establish a position of patient anatomy. However, as the surgical site <NUM> is located a distance away from the reference marker <NUM>, movement of patient anatomy, i.e., the vertebra <NUM>, at the surgical site can go undetected by the global navigation system. As will be described in detail below, in some embodiments, the controller <NUM> can receive data from the localized navigation sensor with respect to localized movement of the anatomic structure <NUM> and can determine whether the detected localized movement is tracked or registered in the global navigation coordinate system. Additionally or alternatively, the controller <NUM> can determine whether the detected localized movement exceeds a threshold condition. In some embodiments, the controller <NUM> can be in communication with a display <NUM> such that information from the controller can be visually communicated to a user via the display. For example, the controller <NUM> can alert a user if detected localized movement exceeds the threshold condition and/or if detected localized movement is not tracked by the global navigation system. In some embodiments, a visual alert or warning sign can be shown on the display <NUM> to alert a user to such conditions. By way of further example, the display <NUM> can show a three-dimensional rendering of patient anatomy, the surgical site, tracked components, etc..

<FIG> is a detailed view of the cannula <NUM> illustrated in <FIG> in connection with the surgical system <NUM>. The cannula <NUM> can have a generally tubular body with an inner lumen <NUM> extending from the proximal end 102p to the distal end 102d of the cannula. As noted above, in some embodiments, the proximal end 102p of the cannula can be coupled to the robot arm <NUM> such the robot arm can control, in whole or in part, movement or placement of the cannula. In other embodiments, a user can manipulate the cannula <NUM> without assistance from the robot arm <NUM> or other surgical robot device. The proximal end 102p of the cannula <NUM> can have an enlarged diameter D1 relative to a diameter D2 of a central portion 102c of the cannula. A collar <NUM> can be formed at the proximal end 102p of the cannula <NUM> which can, in some embodiments, facilitate coupling of the cannula to the robot arm <NUM>. The distal end 102d can have a generally conical shape which can taper from the central portion 102c of the cannula to a distal tip <NUM>. As can be better seen in later figures, the distal tip <NUM> can include a plurality of teeth (e.g., teeth <NUM> in <FIG>) that can grip or bite into an anatomic structure (e.g., vertebra <NUM>) and provide stabilization of the cannula <NUM> relative to the anatomic structure.

The cannula <NUM> illustrated in <FIG> is one embodiment of a cannula according to the present disclosure, i.e., a cannula that can have a localized navigation sensor coupled thereto such that, with the cannula located in proximity to an anatomic structure at a surgical site, the localized navigation sensor can detect movement of the anatomic structure relative to the cannula. Various embodiments of localized navigation sensors of the present disclosure are described in greater detail below. For example, a localized navigation sensor can include one or more of a resistance-based sensor to detect force and/or displacement, a strain gauge, an ultrasound transducer, a laser, an electromagnetic tracker, a piezoelectric actuator, a piezoelectric sensor, or combinations thereof. Further, in some embodiments, a localized navigation sensor can include a fiber optic cable and/or camera(s) that can provide visualization of the anatomic structure. For example, a fiber optic cable can extend through the cannula <NUM> to the distal end 102d and/or camera(s) can be coupled to the distal end of the cannula, such that the surrounding surgical site, including the vertebra <NUM>, can be imaged. In some embodiments, a localized navigation sensor can include multiple cameras, which can enable three-dimensional visualization of the anatomic structure and surgical site.

<FIG> illustrate further embodiments of cannulas and localized navigation sensors that can be used in the surgical system of <FIG>. The localized navigation sensors of these embodiments can include one or more tines that can selectively extend from a distal end of the cannula to contact an anatomic structure and detect localized movement of the anatomic structure relative to the cannula. In embodiments having a plurality of tines, the tines may be extended from the distal end of the cannula independently from one another or in unison with one or more other tines. Depending on the surrounding anatomic structure, in some instances, extending the tines, or a subset of tines, independently can aid in conforming the tines to the anatomic structure.

<FIG> shows one embodiment of a cannula <NUM> with a localized navigation sensor <NUM> coupled thereto. The cannula can be inserted into a surgical site such that a distal end 202d of the cannula <NUM> is in proximity to an anatomic structure, e.g., vertebra <NUM>. While not shown, a proximal end of the cannula <NUM> can be similar or identical to the proximal end 102p of the cannula <NUM> described above in connection with <FIG>. A lumen <NUM> (see <FIG>) can extend from the proximal end to the distal end 202d of the cannula <NUM>. The localized navigation sensor <NUM> can be coupled to the distal end 202d of the cannula and can detect and measure movement of the vertebral body <NUM> relative to the cannula <NUM>. The localized navigation sensor <NUM> can include a plurality of tines <NUM> that can move longitudinally relative to the cannula <NUM> such that the tines <NUM> can extend distally past a distal tip <NUM> of the cannula <NUM> to contact the vertebral body <NUM>, as shown in <FIG>. In some embodiments, the plurality of tines <NUM> can bite into the vertebral body <NUM>. Upon localized movement of the vertebral body <NUM>, one or more of the plurality of tines <NUM> can undergo a change in tine geometry and/or location. The localized navigation sensor <NUM> can collect data related to the same and transmit the data to a controller, e.g., the controller <NUM> of <FIG>, such that the localized movement can be detected and analyzed. While the illustrated embodiment of <FIG> shows the cannula <NUM> placed such that the tines <NUM> contact a surface of the vertebral body <NUM>, alternative positioning of the cannula relative to the vertebra is within the scope of the present disclosure. For example, the cannula <NUM> can be placed at the surgical site such that the tines <NUM> can extend distally from the cannula to contact a surface of a pedicle <NUM> of the vertebral body.

<FIG> show the cannula <NUM> and the localized navigation sensor <NUM> of <FIG> in greater detail. The plurality of tines <NUM> of the sensor <NUM> can move between a first position in which the tines can be retracted within the cannula (see <FIG>) and a second position in which the tines can extend longitudinally from the cannula (see <FIG>). With reference to <FIG>, the distal end 202d of the cannula <NUM> can include a plurality of recesses <NUM> spaced apart along a circumference of the cannula body. In some embodiments, each recess <NUM> can be a slot that extends proximally from the distal tip <NUM> of the cannula <NUM> along a longitudinal axis of the cannula and can terminate at a location on the distal end 202d of the cannula a distance A from the distal tip. A tooth <NUM> can be formed between adjacent recesses <NUM> such that the distal tip <NUM> of the cannula <NUM> can have a plurality of spaced apart teeth.

A tine <NUM> can be received in one or more of the recesses <NUM>. By way of example, six recesses <NUM> can be formed in the distal end 202d of the cannula <NUM> and can be spaced evenly or otherwise along a circumference of the cannula, with a tine <NUM> received within each recess. While six tines <NUM> arranged in the illustrated configuration of <FIG> can provide certain benefits, e.g., decoupling modes of localized movement, a greater or fewer number of tines and/or varying spacing between each tine in an even or unevenly distributed manner can be utilized in localized navigation sensors without departing from the scope of the present disclosure. In the first position, e.g., as shown in <FIG>, a proximal end 208p of each tine <NUM> can be abut a proximal end 212p of the respective recess <NUM> and a distal end 208d of each tine can be flush with a distal end 214d of respective adjacent teeth <NUM> such that the distal end <NUM> of the cannula has a substantially continuous outer surface. As used herein, "outer surface" can refer to a surface facing away from the inner lumen of the cannula <NUM>. The tines <NUM> can be sized and shaped such that, in the first position, an outer surface of each tine <NUM> can lie flush with an outer surface of the adjacent teeth <NUM>.

<FIG> shows the cannula <NUM> with the localized navigation sensor <NUM> in the second position, in which the tines <NUM> can extend distally beyond the distal tip <NUM> of the cannula. More particularly, the tines <NUM> can be actuated from the first position (see <FIG>) such that the tines <NUM> move distally relative to the cannula <NUM> to extend distally from each tine's respect recess <NUM>. The tines <NUM> can be extended until the distal tip 208d of the tines <NUM> contact the vertebral body <NUM>, such that the tines can engage with or bite into the vertebral body. The tines <NUM> can be formed from a sturdy deformable material, e.g., an elastic metallic material, such that the tine may exhibit a deflection or deformation response to movement of the vertebral body <NUM>.

In use, the cannula <NUM> can be inserted into a surgical site (see <NUM> in <FIG>) with the tines <NUM> in the first position (see <FIG>), i.e., retracted into the recesses <NUM> of the cannula. The tines <NUM> can be extended distally (see <FIG>) beyond the distal tip <NUM> of the cannula <NUM> such that the tines <NUM> contact the vertebral body <NUM> at the surgical site (see <FIG>). One or more of the tines <NUM> can include a sensing element that can collect data which can be analyzed to detect and identify relative movement of the anatomic structure. In some embodiments, each of the tines <NUM> can include a sensing element, while in other embodiments only a subset of the tines <NUM> can include a sensing element. The remaining tines can be non-sensing tines, which can provide benefit to the overall design and function of the cannula <NUM>, e.g., as structural support.

<FIG> illustrate various embodiments of tines <NUM> that can be used in accordance with the localized navigation sensor <NUM> described above with respect to <FIG>. As introduced above, the tine <NUM> can include a sensing element such that, when the tine is in contact with patient anatomy, one or more of a geometry of the tine, position of the tine, and orientation of the tine can change in response to movement of the patient anatomy. The tine <NUM> can collect data associated with such change(s) and the localized navigation sensor can transmit the data to a controller <NUM> (see <FIG>) for analysis.

<FIG> illustrate various embodiments of tines <NUM>', <NUM>", <NUM>‴ of the present disclosure that can include a resistance-based sensor or a resistive element therein. For example, as shown in <FIG>, in some embodiments tines <NUM>', <NUM>" can include one or more resistive element channels <NUM>, 216a, 216b, 216c that can extend through a body of the tine and measure resistance to detect force and/or displacement. A resistance measured by the resistive element channels <NUM>, 216a, 216b, 216c of a particular tine <NUM>', <NUM>" can correlate to an amount of bending that particular tine undergoes at the time. In some embodiments, a tine <NUM>' can include a single resistive channel <NUM> extending from a proximal end of the tine 208p' towards a distal tip 208d' of the tine (see <FIG>). The resistive channel <NUM> can extend substantially centrally through the tine <NUM>', although other placements of the channel are possible. In another embodiment, as shown in <FIG>, a tine <NUM>" can include three resistive channels 216a, 216b, 216c, that can extend through the body of the tine. In some such embodiments, the three resistive channels 216a, 216b, 216c can be placed in a triangular configuration and substantially centrally located within the tine. The multiple resistive channels 216a, 216b, 216c contained within the single tine <NUM>" can provide for a precise measurement of a direction of bending of the tine, as the resistance measurements from each of the three resistive channels can be analyzed and decoupled from one another. The resistive channels <NUM>, 216a, 216b, 216c can be formed from a resistive piece of material or a filament extending through the interior of the tine <NUM>', <NUM>". By way of non-limiting example, each resistive channel <NUM>, 216a, 216b, 216c can have a diameter D3 (see <FIG>) of about <NUM> to about <NUM>. The particular configuration, number of resistive channels, length of resistive channel, and/or diameter of resistive channel, can be determined based on, among other things, size of the tine <NUM>', <NUM>" and a desired sensor response. The resistive element channels <NUM>, 216a, 216b, 216c can have an exposed face <NUM>, 217a, 217b, 217c at the proximal end 208p', 208p" of the tine <NUM>', <NUM>", which can serve as a connection for signal transmission from the tine <NUM>', <NUM>" to the controller <NUM> (see <FIG>).

<FIG> illustrates another embodiment of a tine <NUM>‴ with a resistive element <NUM> that can measure an amount of bending in the tine. A body <NUM> of the tine <NUM>‴ can be a nonconductive elastomer. The resistive element <NUM> can be formed by doping an interior portion of the body <NUM> with a conductive metal, such that the resistive element <NUM> forms a core within the body <NUM>. This can be seen in inserts A and B of <FIG>, which show the tine <NUM>‴ with a partially transparent body <NUM> and a partially cut-away body <NUM>, respectively. A proximal face <NUM> of the resistive element <NUM> can be exposed at a proximal end 208p‴ of the tine <NUM>‴, which can serve as an electrical connection for signal transmission between the tine <NUM>‴ and the controller <NUM> (see <FIG>).

<FIG> illustrate alternative embodiments of a tine 208a, 208b that can include at least one strain gauge 224a, 224b placed on or within the tine. The strain gauge(s) 224a, 224b can measure deformation of and/or pressure changes on the tine 208a, 208b. In some embodiments, the strain gauge 224a, 224b can be embedded directly into the tine 208a, 208b, while in other embodiments the strain gauge can be bonded to, or otherwise securely attached to, a surface of the tine 208a, 208b. <FIG> illustrates one embodiment in which the strain gauge 224a can be placed on an inner surface <NUM> of the tine 208a. As used herein, "inner surface" can refer to a surface facing towards the lumen <NUM> (see <FIG>) of the cannula <NUM>. In other embodiments, either additionally, or alternatively, the strain gauge 224b can be placed on an outer surface <NUM> of the tine 208b, as shown in <FIG>. For a tine with an arcuate structure, the inner surface <NUM> can be concave and the outer surface <NUM> can be convex. The strain gauge 224a, 224b can be placed towards a distal tip 209a, 209b of the tine 208a, 208b, to the extent that the geometry of the tine and the gauge allow. Exact placement of the strain gauge 224a, 224b can be a function of tine geometry and/or strain gauge width. Size, shape, and placement of the strain gauge(s) 224a, 224b can vary based on, among other things, the dimensions of the tine 208a, 208b and desired sensitivity of the measurements. For example, in some embodiments a strain gauge can have an elongate-rectangular configuration, such as the strain gauge 224a of <FIG>, while in other embodiments a strain gauge can have a more square-shaped configuration, such as the strain gauge 224b in <FIG>. One example of a strain gauge that can be used in accordance with the present disclosure is a Vishay General Purpose Linear Pattern Strain Gage that can be about <NUM> by about <NUM> by about <NUM>.

While the embodiments illustrated in <FIG> show a single strain gauge 224a, 224b coupled to a tine 208a, 208b, in some embodiments, an array of strain gauge sensors can be placed along an inner and/or outer surface of the tine, which can enable increased precision sensing and lead to a better understanding of localized movement of the patient anatomy. As discussed in detail with reference to <FIG>, in some embodiments, an array of strain gauge sensors can be placed on the tine such that the sensor signals can be decoupled from one another and the various individual modes of localized movement, e.g., lateral translation, longitudinal translation, rotation, can be distinctly identified.

One or more conductive paths or wires (e.g., wire <NUM> in <FIG>) can connect to the electrical connection of the resistance-based sensors/resistive elements <NUM>, 216a, 216b, 216c, <NUM> or strain sensors 224a, 224b, described above. More particularly, the wire(s) <NUM> can extend along an interior or exterior of the cannula <NUM> to transmit the signals from the sensing elements of the localized sensor <NUM> to the controller <NUM> (<FIG>). While only a single wire <NUM> in connection with a single tine <NUM> is illustrated in 4C, each tine of the localized navigation sensor <NUM> that includes a sensing element can have a connection to the controller <NUM> for transmitting data. Alternatively, transmission of data from the localized sensor <NUM> to the controller <NUM> can be done, in whole or in part, via a wireless connection. In instances in which the cannula <NUM> and localized navigation sensor <NUM> are utilized with the robot arm <NUM> (<FIG>), the conductive path or wire <NUM> can extend to an end effector of the robot arm, which can process data from the localized sensor <NUM>, e.g., with a printed circuit board (PCB) integrated within the end effector or robot arm, or further transmit the signals to a connected controller through a wired or wireless transmission. During manufacture, the localized navigation sensor <NUM> can be calibrated by determining the correlation between a reading of the resistance-based sensor(s)/resistive element(s) <NUM>, 216a, 216b, 216c, <NUM> and/or strain gauge(s) 224a, 224b of a particular tine and deflection or deformation of the tine. The resulting calibration values can be encoded, e.g., in a chip onboard the cannula <NUM> (which can be in the same electronics package as the conductive wires <NUM>), via a quick response (QR) code or bar code on cannula packaging, etc., and retrieved prior to or during a surgical procedure for signal processing.

<FIG> illustrate another embodiment of a cannula <NUM> with a localized navigation sensor <NUM> coupled thereto in accordance with the present disclosure. <FIG> shows the cannula <NUM> located at a surgical site <NUM> (see <FIG>) such that a distal tip <NUM> of the cannula can contact a vertebral body <NUM>, or other anatomic structure. Contact between the distal tip <NUM> and the vertebral body <NUM> can stabilize the cannula <NUM> within the surgical site. The localized navigation sensor <NUM> can include at least one tine <NUM> that can extend radially outward from a distal end 300d of the cannula. More particularly, the tine <NUM> can extend outwardly from the cannula <NUM> and can contact the vertebral body <NUM> at a location that is remote from a location of contact between the distal tip <NUM> of the cannula and the vertebral body. The tine <NUM> can include one or more of the sensing elements described above in connection with <FIG> such that the tine and more broadly, the localized navigation sensor <NUM>, can collect data with respect to a geometry, position, location, etc. of the tine that can be used to detect localized movement of the vertebral body <NUM>. For example, bending of the tine <NUM> can indicate a change or shift in a direction of movement of the vertebral body <NUM> relative to the cannula <NUM>. Deflection of the tine <NUM> can measure force of localized movement of the anatomy <NUM>. In some embodiments, a plurality of tines <NUM> can extend radially outward from the cannula <NUM>, with each tine configured to contact the vertebral body <NUM> at a location remote from the distal tip <NUM> of the cannula. Each of the plurality of tines <NUM> can include a sensing element, which can provide increased data with respect to detecting and identifying a direction and/or magnitude of localized movement.

As discussed above, localized navigation sensors <NUM>, <NUM> of the present disclosure can be configured such that signals received by the controller <NUM> from the localized navigation sensors can be decoupled, which can lead to a precise determination of localized movement mode, magnitude, and direction of the vertebra <NUM>, <NUM>, or other anatomic structure. Decoupling sensor signals can be beneficial as the anatomic structure can move relative to the cannula in three different modes, simultaneously. Namely, and with reference to <FIG> which schematically illustrates the various modes of motion, an anatomic structure <NUM> can translate laterally (schematically illustrated in box A), translate longitudinally (schematically illustrated in box B), and rotate (schematically illustrated in box C) to varying degrees at the same time, such that a simple measurement reading from a localized navigation sensor may not always be sufficient to fully capture localized movement. By decoupling the signal(s) received from the localized navigation sensor <NUM>, <NUM>, the controller <NUM> of the present disclosure can identify each of the three modes of movement described above independently of one another. In this manner, localized movement of the patient anatomy relative to the cannula can be accurately and precisely measured and tracked.

In some embodiments, a statistical model can be programmed into the controller <NUM> to read and decouple the signals received from the localized navigation sensor <NUM>, <NUM>. In other embodiments, analytical decoupling can be performed. More particularly, and with reference to <FIG>, a localized navigation sensor of the present disclosure can include six tines <NUM>, <NUM>, placed in the configuration <NUM> of <FIG>, i.e., spaced equidistant around a circumference of a cannula <NUM>, <NUM> such that three pairs of opposed sensors are formed. As noted above, localized navigation sensors and instruments in accordance with the present disclosure may have an alternative number and/or spacing of tines (e.g., with even or uneven spacing of tines). By way of example, such an analytical decoupling of data from tines in such a configuration can be analytically akin to a strain gauge rosette. Each of the six tines <NUM>, <NUM> can include resistance-based sensors/resistive elements <NUM>, 216a, 216b, 216c, <NUM> or strain sensors 224a, 224b. With the tines <NUM>, <NUM> in such a configuration, the signal transmissions from each tine can be read and analyzed to identify the composite movement by magnitude and direction of strain and shear. For example, the controller <NUM> can identify a magnitude and direction of longitudinal strain by analyzing components of the data transmitted by each tine as shown in the sensor response diagram <NUM>. Similarly, the controller <NUM> can identify a magnitude and direction of lateral strain by analyzing components of the data transmitted by each tine as shown in the sensor response diagram <NUM>. By process of elimination, remaining components of the data transmitted by each tine can be attributed to shear.

In instances or applications in which a signal from the localized navigation sensor cannot be easily decoupled, higher techniques of signal processing can be deployed to capture and identify precise localized movement of the patient anatomy at interest. For example, multimodal machine learning techniques can be applied to enhance movement detection and measurement. <FIG> schematically illustrates one embodiment of a multimodal machine learning system <NUM> that can be utilized by the controller <NUM> (see <FIG>) of the present disclosure to process signals received from the localized navigation sensor. For example, the controller <NUM> can include a machine learning module <NUM> that can build a framework through which data from the localized sensor <NUM>, <NUM> can be interpreted such that localized movement mode(s) and respective magnitude(s) can be determined. The machine learning module <NUM> can receive as input pre-programed information <NUM> pertaining to anatomy at the surgical site <NUM> (see <FIG>). The pre-programed information <NUM> can include generic anatomic information and/or patient-specific information. The machine learning module <NUM> can receive as further inputs data from various pre-operative or intra-operative tests or scans related to the patient's anatomy at the surgical site, such as, for example, ultrasound data <NUM>, three-dimensional maps <NUM>, and/or data from sensors embedded in surgical instruments <NUM>. The machine learning module <NUM> can take these inputs <NUM>, <NUM>, <NUM>, <NUM> and construct three-dimensional models of anatomy at the surgical site, filter and flatten the signals, and segment and label the data to build a framework understanding of the surgical site anatomy. The controller <NUM> can then apply the machine learning framework <NUM> to signals received from the localized navigation sensors <NUM>, <NUM> to understand and capture precise localized movement based on the localized navigation sensor data.

<FIG> illustrate alternative embodiments of cannulas and localized navigation sensors in accordance with the present disclosure. As with the embodiments described above, the cannulas and localized navigation sensors of <FIG> can be used in conjunction with a global navigation system during a surgical procedure, e.g., as part of the surgical system <NUM> of <FIG> or can be used during a surgical procedure independent of a global navigation system. Further, in some embodiments, the cannulas of <FIG> can be coupled to a surgical robot, e.g. robot arm <NUM>, such that the robot can control or assist with control of the cannula and/or localized navigation sensors.

<FIG> shows one embodiment of a cannula <NUM> and a localized navigation sensor in the form of a sheath <NUM> in accordance with the present disclosure. <FIG> show detailed views of a distal end 402d of the cannula inserted into a surgical site (<NUM>). The cannula <NUM> can have a generally tubular body extending from a proximal end 402p to the distal end 402d, configured for insertion into the surgical site. As described above in connection with the cannula <NUM> of <FIG>, the cannula <NUM> can taper at the distal end and terminate with a plurality of arcuate teeth <NUM>, which can form a distal tip of the cannula and can contact patient anatomy, e.g., vertebral body <NUM> at the surgical site. The teeth <NUM> can bite into or otherwise engage the vertebral body <NUM>, which can stabilize the cannula <NUM> against the bone. The sheath <NUM>, i.e., the localized navigation sensor, and can be coupled to the distal end 400d of the cannula <NUM>. More particularly, a proximal end 402p of the sheath <NUM> can extend around a circumference of the cannula <NUM> and can expand radially outwards to a distal end 402d of the sheath. The distal end 402d of the sheath <NUM> can terminate in-line with the distal tip of the arcuate teeth <NUM> of the cannula <NUM>, such that the distal tip of the arcuate teeth <NUM> can be aligned or substantially aligned with the distal end of the sheath. With the cannula <NUM> inserted into the surgical site such that the arcuate teeth <NUM> of the cannula can contact the vertebral body <NUM> at a first location <NUM>, the distal end 402d of the sheath <NUM> can contact the vertebral body at a second location <NUM>, which can extend along an entire circumference of the sheath's distal end or along a part or parts thereof. The sheath <NUM> can deflect or deform in response to localized movement of the vertebral body <NUM>. Deflection, deformation, and/or movement of the sheath <NUM> can be measured, e.g., by one or more resistance-based sensors/resistive element(s) and/or strain gauge(s) as described above, of the sheath <NUM> and the data can be transmitted to a controller <NUM> (see <FIG>) for further processing to detect localized movement.

<FIG> illustrates another embodiment of a cannula <NUM> and a localized navigation sensor <NUM> in accordance with the present disclosure. As discussed in detail below, the localized navigation sensor <NUM> can generate vibration of the cannula <NUM> and can be configured to monitor a resonant frequency of the cannula in response to the vibrations. A change in resonant frequency can be detected by the localized navigation sensor <NUM>, which can correspond to localized movement of an anatomic structure at a surgical site. Turning to <FIG>, the cannula <NUM> can have a generally tubular body extending between a proximal end 500p and a distal end 500d. The distal end 500d of the cannula <NUM> can include a plurality of teeth <NUM> that can contact a pedicle <NUM>, or other anatomic structure. In some embodiments, the localized navigation sensor <NUM> can be a piezoelectric sensor configured to detect force and/or deflection. In some embodiments, a piezoelectric actuator can be employed that can include an emitter and a receiver, such that the single piezoelectric component can cause a vibration of the cannula <NUM> and can measure a resonant frequency response. In other embodiments, emitter and receiver components of the localized navigation sensor <NUM> can be separately coupled to the cannula <NUM>. As shown in <FIG>, the localized navigation sensor <NUM> can be mounted or otherwise coupled to the proximal end 500p of the cannula <NUM>. Wires <NUM> can extend from the localized navigation sensor <NUM> along the cannula <NUM> to provide a transmission path for data between the localized navigation sensor and a controller <NUM> (see <FIG>). In other embodiments, communication between the localized navigation sensor <NUM> and the controller can occur through a wireless connection. In some embodiments, a localized navigation sensor <NUM>' can be coupled to a distal end 502d' of a cannula <NUM>', as shown in an alternative embodiment of <FIG>. By way of non-limiting example, the localized navigation sensor <NUM>, <NUM>' can be a piezo-film vibration sensor produced by TE Connectivity with dimensions of about <NUM> by about <NUM> by about <NUM>. Alternative sizes and shapes of the localized navigation sensor <NUM>, <NUM>' fall within the scope of this disclosure and can be determined, at least in part, on the dimensions of the cannula <NUM>, <NUM>'. The localized navigation sensor <NUM>, <NUM>' can be calibrated to establish a baseline resonant frequency measurement each time a surgical instrument is introduced to the surgical site such that changes to the resonant frequency of the cannula <NUM>, <NUM>' can be accurately attributed to localized movement of patient anatomy at the surgical site, rather than introduction of a surgical instrument.

<FIG> illustrate another embodiment of a cannula <NUM> and a localized navigation sensor <NUM> in accordance with the present disclosure. Except as described in detail below, the cannula <NUM> can be similar or substantially similar to the cannulas <NUM>, <NUM> described above. The localized navigation sensor <NUM> can be a miniature or micro ultrasound transducer and sensor, which can be used, for example, in a minimally invasive surgical procedure (MIS procedure) in which the ultrasound can measure and monitor position and/or movement of an anatomic structure (e.g., a vertebral body <NUM>, a pedicle <NUM>, etc.) at a surgical site that can be devoid of any airgaps. In other words, the localized navigation sensor <NUM> can measure and/or monitor the anatomic structure through tissue and/or fluids at the surgical site. In some embodiments, the localized navigation sensor <NUM> can be embedded into the cannula <NUM> at a distal end 602d thereof. A protrusion <NUM> can be formed around the localized navigation sensor <NUM> such that the sensor can be slightly raised, e.g., up to about <NUM>, off of the surface of the cannula. In some embodiments, the cannula <NUM> can include a plurality of recesses <NUM>, as described above in connection with <FIG>, and, by way of non-limiting example, the localized navigation sensor <NUM> can be placed adjacent to a proximal end 606p of one or more of the recesses. In use, the cannula <NUM> can be inserted into the surgical site <NUM> (<FIG>) and brought into proximity of the pedicle <NUM> (<FIG>), or other anatomic structure. The cannula <NUM> can be rotated such that the localized navigation sensor <NUM> can image or capture a portion of the pedicle <NUM>. A controller <NUM> (<FIG>) can then produce and track the image to visualize bone shape of the pedicle and illustrate localized movement thereof. In some embodiments, an ultrasound frequency from the localized navigation sensor <NUM> can be monitored. Changes in the ultrasound frequency can reflect bone material of the anatomic structure of interest, e.g., the pedicle.

<FIG> shows another embodiment of a cannula <NUM> with a localized navigation sensor <NUM> coupled to a distal end 700d thereof inserted into a surgical site such that the localized navigation sensor can monitor and detect relative movement of a vertebra <NUM>, or other anatomic structure, at a surgical site <NUM> (see <FIG>). Except as described below, the cannula <NUM> can be similar or identical to any of the cannulas described above. Accordingly, description of the cannula's <NUM> structure, operation, and use is omitted herein for the sake of brevity. The localized navigation sensor <NUM> can include one or more micro laser arrays embedded into or otherwise secured to the body of the cannula <NUM> at the distal end 700d thereof. In one embodiment, with the cannula <NUM> in proximity to and, in some embodiments, in contact with, the vertebra <NUM>, the localized navigation sensor <NUM> can perform beam scanning <NUM> of the vertebra <NUM>, or a portion thereof, without contact between the localized navigation sensor and the vertebra. A controller <NUM> (see <FIG>) can receive data from the localized navigation sensor <NUM> and, leveraging different wavelengths of the data, can create a reconstruction, e.g., a three-dimensional model, of the vertebra <NUM> and any surrounding structures captured by the beam scanning <NUM>. The localized navigation sensor <NUM> can continuously scan the vertebra <NUM> such that localized movement of the vertebra <NUM> can be detected in the reconstruction by the controller <NUM>. Additionally, or alternatively, the localized navigation sensor <NUM> can take repeated distance measurements to a single-point or line, e.g., a point or line on a spinous process <NUM> of the vertebra <NUM> and can detect localized movement of the spinous process from a change in the distance measurement. In other words, if the facet or spinous process <NUM> moves relative to the cannula <NUM>, a distance measurement by the localized navigation sensor <NUM> to a constant single-point or along a constant line will increase or decrease as a function of the movement.

<FIG> illustrates another embodiment of a cannula <NUM> with a localized navigation sensor <NUM> coupled to a distal end 800d thereof inserted into a surgical site <NUM> (see <FIG>) such that the localized navigation sensor can monitor and detect relative movement of a vertebra <NUM>, or other anatomic structure, at the surgical site. Except as described below, the cannula <NUM> can be similar or identical to any of the cannulas described above. Accordingly, description of the cannula's <NUM> structure, operation, and use is omitted herein for the sake of brevity. The localized navigation sensor <NUM> can be an electromagnetic tracker that can measure an electromagnetic field of the surroundings and detect a magnitude of change therein. In one embodiment, one or more electromagnetic sensors <NUM> can be injected or otherwise placed into the vertebra <NUM> and can serve as landmarks for the localized navigation sensor <NUM>. In the illustrated embodiment, the electromagnetic sensor <NUM> can be injected into a base of the spinous process <NUM>, however alternative placement of the electromagnetic sensor can be utilized. By way of non-limiting example, the electromagnetic sensor <NUM> can be an NDI Micro 6DOF Sensor, with a diameter of about <NUM> and a height of about <NUM>. In some embodiments the electromagnetic sensor <NUM> can be encased in a capsule, e.g., a capsule with a diameter of about <NUM> and a height of about <NUM>. With the electromagnetic sensor <NUM> in place, the localized navigation sensor <NUM> can monitor the electromagnetic field at close proximity, which can reduce noise in the signal, and can detect localized movement of the vertebra <NUM> based on unexpected change in the electromagnetic field. In embodiments in which no electromagnetic sensors <NUM> are placed in the vertebra <NUM>, the localized navigation sensor <NUM> can monitor an electromagnetic field in proximity to the vertebra once a screw or other metallic hardware (not shown) is placed in the vicinity of the surgical site <NUM>, e.g., a pedicle screw is placed in a pedicle <NUM> of the vertebra <NUM> or in a pedicle of an adjacent vertebra. With the metallic hardware in place, the localized navigation sensor <NUM> can establish a baseline measurement for the electromagnetic field and can detect changes thereto. A significant change in the electromagnetic field can thus be correlated to a change in position of the vertebra <NUM>.

<FIG> illustrates one embodiment of a method <NUM> (not falling under the claimed scope) for detecting localized movement of an anatomic structure at a surgical site, which can be performed with any of the systems and devices described herein. In some embodiments, the method <NUM> can include alerting a user when detected localized movement exceeds a threshold condition, e.g., as described in connection with box I of <FIG>. Additionally or alternatively, in some embodiments, the method <NUM> can determine whether detected localized movement is recognized or registered by a global navigation system, e.g., as described in connection with box II of <FIG>. By way of example, the method <NUM> is described below with reference to the surgical system <NUM> of <FIG> and the cannula <NUM> and localized navigation sensor <NUM> of <FIG>, however, any of the systems and devices described herein can be utilized in connection with the method described below.

The method <NUM> can include inserting a cannula <NUM>, or other instrument, with a localized navigation sensor <NUM> coupled thereto into a surgical site <NUM> (step <NUM>) and placing the cannula in a desired position for detection of localized movement of a vertebral body <NUM>, or other anatomic structure, at the surgical site (step <NUM>). This can include, for example, advancing the cannula <NUM> towards the vertebral body <NUM> such that a distal end 200d of the cannula is in proximity to the vertebral body. More particularly, the cannula <NUM> can be placed such that the localized navigation sensor <NUM> coupled to the cannula is brought into a position to collect data upon movement of the vertebral body <NUM> relative to the cannula <NUM>. For example, one or more tines <NUM> can be advanced from the distal end 200d of the cannula <NUM> to contact the vertebral body <NUM>. In some embodiments, the cannula <NUM> can be coupled to a robot arm <NUM> (see <FIG>), or other surgical robot device, which can control or assist in controlling movement of the cannula <NUM> and/or actuation of the localized navigation sensor <NUM>, e.g., extension of the tines <NUM>.

With the cannula <NUM> placed in the desired position, the localized navigation sensor <NUM> coupled to the cannula can monitor a position of the vertebral body <NUM> and detect movement of the vertebral body <NUM> relative to the cannula (step <NUM>). More particularly, the localized navigation sensor <NUM> can collect data, e.g., from sensing element(s) within tines <NUM> of the sensor that can respond to movement of the vertebral body <NUM> and transmit the data to a controller <NUM>. The controller <NUM> can analyze the data from the localized navigation sensor <NUM> detect a magnitude, change in direction, and/or mode of movement of the vertebral body <NUM> relative to the cannula. As introduced above, methods described herein can sense localized movement of the vertebral body <NUM> and can determine (i) whether the localized movement exceeds a threshold condition (Box I) and/or (ii) whether the detected localized movement is recognized by a global navigation system <NUM>, <NUM> (Box II). The localized navigation sensor <NUM> can transmit data to a controller <NUM> for further processing and analysis, e.g., to decouple signal transmission from the localized navigation sensor, identify localized movement, etc..

Turning first to embodiments of the method <NUM> that can include determining whether localized movement exceeds a threshold condition (Box I), if localized movement is detected at step <NUM>, the controller <NUM> can determine whether the detected localized movement exceeds a threshold condition (step <NUM>). By way of non-limiting example, the controller <NUM> can determine a magnitude of localized movement of the vertebral body <NUM> based on the data received from the localized navigation sensor <NUM> and can compare the detected magnitude of localized movement to a threshold amount of movement, e.g., a pre-determined magnitude of movement that could result in a drill or other tool moving off-target of an intended trajectory (i.e., skiving). By way of further example, in some embodiments, the controller <NUM> can determine a directional shift of the detected localized movement and compare the directional shift to a threshold condition set of permissible localized movement directions. If the detected localized movement exceeds the threshold condition (e.g., the threshold magnitude of movement, the permissible localized movement directions, etc.) a user can be alerted (step <NUM>). Alerting the user can include, for example, triggering a visual, auditory, and/or haptic feedback such that a user can be made aware of the exceeded threshold condition. In some embodiments, alerting the user can include logging information in a connected server or computing system. If the detected localized movement does not exceed the threshold condition (step <NUM>) the surgical procedure can continue (<NUM>). While the surgical procedure continues, the localized navigation sensor <NUM> can continuously detect localized movement and the method can revert back to step <NUM>.

If localized movement is detected (step <NUM>) and a global navigation system <NUM>, <NUM> is utilized during a surgical procedure, the method <NUM> can determine whether detected localized movement is tracked by the global navigation system, i.e., whether the movement of the vertebral body <NUM> is reflected in the coordinate system established by the global navigation system (step <NUM>). For example, the controller <NUM> can receive data from the localized navigation sensor <NUM> and the global navigation system <NUM>, <NUM>. The controller <NUM> can compare the detected localized movement, i.e., as determined from the localized navigation sensor data, to the data from the global navigation system regarding placement of the tracked marker(s) and determine whether the detected localized movement of the vertebral body <NUM> is reflected in the data from the global navigation system. If the detected localized movement of the vertebral body <NUM> is not tracked by the global navigation system, a user can be alerted (step <NUM>), which can include any of the alert measures described above with respect to step <NUM>. The alert issued to the user can signal to the user that there is an increased risk of skiving when a navigated instrument is introduced and/or manipulated at the surgical site resulting from inaccuracy in the global navigation system with respect to placement and/or positioning of the vertebral body <NUM>. On the other hand, if the detected localized movement is tracked by the global navigation system, then the surgical procedure can continue (step <NUM>). The localized navigation sensor <NUM> can continuously detect localized movement and the method can revert back to step <NUM>.

While the steps of determining whether detected localized movement exceeds a threshold condition (<NUM>) and determining whether detected localized movement is reflected in a global coordinate frame (<NUM>) are illustrated in <FIG> as separate sub-processes in Box I and Box II, respectively, in some embodiments, systems and methods of the present disclosure can be configured to carry out all of the steps within Box I and Box II. For example, a controller of the present disclosure can be configured to receive data from a localized navigation sensor, determine whether the detected localized movement exceeds a threshold condition (Box I), and determine whether the detected localized movement is reflected in the global coordinate frame (Box II). The steps of Box I and Box II can be carried out simultaneously, sequentially, or individually in response to an instruction command, e.g., that can be pre-programmed into the controller, downloaded from a connected device, input by a user, etc..

Claim 1:
A surgical system (<NUM>), comprising:
a robot arm (<NUM>);
a cannula (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) coupled to the robot arm (<NUM>);
a localized navigation sensor (<NUM>, <NUM>; <NUM>; <NUM>, <NUM>, <NUM>'; <NUM>); and
a controller (<NUM>) configured to:
receive data from the localized navigation sensor (<NUM>, <NUM>; <NUM>; <NUM>, <NUM>, <NUM>'; <NUM>);
receive data from a global navigation system (<NUM>, <NUM>) that tracks a location of a navigation marker located remotely from the anatomic structure (<NUM>);
characterised in that the localized navigation sensor (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>'; <NUM>) is coupled to a distal end (102d; 202d; 300d; 402d; 500d, 502d'; 602d) of the cannula (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) and configured to detect movement of an anatomic structure (<NUM>) relative to the cannula (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>); and in that
the controller (<NUM>) is further configured to determine if movement of the anatomic structure (<NUM>) detected by the localized navigation sensor (<NUM>, <NUM>; <NUM>; <NUM>, <NUM>, <NUM>'; <NUM>) is tracked by the global navigation system.