WO2025158388A1

WO2025158388A1 - System and method for determining a status of a tracking device

Info

Publication number: WO2025158388A1
Application number: PCT/IB2025/050832
Authority: WO
Inventors: Victor SNYDER; Annie EGAN; Julie MOCKO; Jacob Gerber GERBER; Brian TREMBLAY; Andrew Koert
Original assignee: Medtronic Navigation Inc
Current assignee: Medtronic Navigation Inc
Priority date: 2024-01-25
Filing date: 2025-01-24
Publication date: 2025-07-31
Anticipated expiration: 2026-07-25

Abstract

Disclosed is a system for assisting in guiding and performing a procedure on a subject. The subject may be any appropriate subject such as inanimate object and/or an animate object. A system and/or method may be operable to assist in determining and/or alerting a user to a movement or detachment of a selected tracking device.

Description

SYSTEM AND METHOD FOR DETERMINING A STATUS OF A TRACKING DEVICE

FIELD

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/624,900, filed 25 January 2024, the entire content of which is incorporated herein by reference.

[0003] The subject disclosure is related generally to a tracking and navigation system.

BACKGROUND

[0004] This section provides background information related to the present disclosure which is not necessarily prior art.

[0005] An instrument can be navigated relative to a subject for performing various procedures. For example, the subject can include a patient on which a surgical procedure is being performed. During a surgical procedure, an instrument can be tracked in an object or subject space. The subject may also be tracked with a subject or patient tracker. In various embodiments, the subject space can be a patient space defined by a patient. The location of the instrument that is tracked can be displayed on a display device relative to an image of the patient.

[0006] The position of the patient can be determined with a tracking system. Generally, a patient is registered to the image, via tracking an instrument relative to the patient to generate a translation map between the subject or object space (e.g., patient space) and the image space. This may occur by identifying one or more points in the subject space and correlating, often identical points, in the image space.

[0007] After registration, the position of the instrument can be appropriately displayed on the display device while tracking the instrument. The position of the instrument relative to the subject can be displayed as a graphical representation, sometimes referred to as an icon on the display device.

SUMMARY

[0008] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0009] According to various embodiments, an imaging system may be used to acquire image data of a subject. Image data may be acquired of the subject to generate images of the subject. The pose of one or more portions of the subject and/or other tracked portions relative to the subject may then be displayed with and relative to the image.

[0010] A pose of a selected portion of the subject may be tracked with a subject tracker, also referred to as a patient tracker or dynamic reference frame (DRF). The DRF may be connected to a selected portion of the subject, such as a bony portion. In various embodiments, a single or at least one DRF may be connected to an individual or a separated bone segment. For example, at least one DRF may be connected to selected one or more or each vertebrae of a subject. This may allow for each individual portion, such as individual vertebra, to be tracked separately and distinctly via one or more selected tracking systems.

[0011] An appropriate tracking system may track the DRF. The tracking system may include an electromagnetic (EM) tracking system, optical tracking system, acoustic tracking system, or other appropriate tracking systems. The tracking system may be selected or may include a plurality of tracking systems to track the various trackers.

[0012] Images of the subject may be acquired at any appropriate time as well. The images may be segmented and used to identify various portions of the subject. Each segmented portion, such as a segmented vertebra, may be associated with one of the trackers. Therefore, movement of the DRF may be used to determine or evaluate a pose of the portion (e.g., segmented portion) in the image. If the image is segmented a movement of the individual tracker may be used to update the image to illustrate a movement of the portion to which the tracker is connected in the image.

[0013] The pose of the portion in the image being updated based upon a position of the tracker may be based upon an assumption that the tracker is connected to the portion of the subject illustrated in the image. The tracking system may not properly track a portion of the subject if the tracking device is not selectively (e.g., fixed in at least one degree of freedom) connected to a portion of the subject. Therefore a system, device, or process may be provided to check for connection of the tracking device to the subject. The system may alert a user to a probability, which may also be referred to as or understood as likelihood of a status of the tracking device, such as a probability of the tracking device being detached from the selected portion to be tracked. Understanding, herein probability or likelihood may be used interchangeably and/or with the intent of a broadest understanding and flexibility regarding a comparison of two or more values. “Likelihood” may be understood to be unnormalized numbers that can be compared in a relative sense, without knowledge of a universe of possibilities. “Probability” may be understood to assume some knowledge of all possibilities. Thus, discussion herein using either or both of likelihood probability may be understood to refer to a broadest understanding of comparisons.

[0014] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0015] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0016] Fig. 1 is diagrammatic view illustrating an overview of a robotic system and a navigation system, according to various embodiments; [0017] Fig. 2 is a diagrammatic view of different tracked poses of a subject that are plausible and implausible, according to various embodiments;

[0018] Fig. 3 is a diagrammatic view of different tracked poses of a subject that are plausible and implausible, according to various embodiments;

[0019] Fig. 4 is a diagrammatic view of different tracked poses of a subject that are plausible and implausible, according to various embodiments;

[0020] Fig. 5 is a diagrammatic view of different tracked poses of a subject that are plausible and implausible relative to other anatomy, according to various embodiments;

[0021] Fig. 6 is a diagrammatic view of different tracked poses of a subject and related plausible or implausible derivatives, according to various embodiments;

[0022] Fig. 7 is a diagrammatic view of different tracked poses of a subject that are plausible and implausible and a tracked instrument and no tracked instrument, according to various embodiments;

[0023] Fig. 8 is a diagrammatic view of different tracked poses of a subject that are plausible and implausible, according to various embodiments;

[0024] Fig. 9 is a diagrammatic view of different tracked poses of a subject and a secondary imaging system, according to various embodiments;

[0025] Fig. 10 is a diagrammatic view of tracking device and additional sensors therewith, according to various embodiments;

[0026] Fig. 11 is a diagrammatic view of tracking device with a member and additional sensors with the member, according to various embodiments; [0027] Fig. 12 is a diagrammatic view of tracking device with a member and a switch in a first and second configuration, according to various embodiments;

[0028] Fig. 13 is a diagrammatic view of tracking device with a member and a switch in a first and second configuration, according to various embodiments;

[0029] Fig. 14 is a diagrammatic view of tracking device with a member and a switch in a first and second configuration, according to various embodiments;

[0030] Fig. 15 is a flowchart illustrating a determination with a machine learning system, according to various embodiments;

[0031] Fig. 16 is a flowchart illustrating a use of a navigation system, according to various embodiments;

[0032] Fig. 17 illustrates a schematic tracking system and related expressions;

[0033] Fig. 18 illustrates a schematic tracking system and related expressions;

[0034] Fig. 19 illustrates a schematic tracking system and related expressions;

[0035] Fig. 20 illustrates a schematic tracking system and related expressions; and

[0036] Fig. 21 illustrates a schematic tracking system and related expressions. [0037] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0039] The subject disclosure is directed to an exemplary embodiment of a surgical procedure on a subject, such as a human patient. It is understood, however, that the system and methods described herein are merely exemplary and not intended to limit the scope of the claims included herein. In various embodiments, it is understood, that the systems and methods may be incorporated into and/or used on non-animate objects. The systems may be used to, for example, image and register coordinate systems between two systems for use on manufacturing systems, maintenance systems, and the like. For example, automotive assembly may use one or more robotic systems including individual coordinate systems that may be registered together for coordinated or consorted actions. Accordingly, the exemplary illustration of a surgical procedure herein is not intended to limit the scope of the appended claims.

[0040] Various members or portions thereof may also be tracked relative to the subject. For example, a tracking system may be incorporated into a navigation system to allow tracking and navigation of one or more instruments (which may be the members) that may be tracked relative to the subject. The subject may also be tracked. The navigation system may include one or more tracking systems that track various portions, such as tracking devices, associated with instruments. The tracking system may include a localizer that is configured to determine the position of the tracking device in a navigation system coordinate system. Determination of the navigation system coordinate system may include those described at various references including U.S. Pat. No. 8,737,708; U.S. Pat. No. 9,737,235; U.S. Pat. No. 8,503,745; U.S. Pat. No. 8,175,681 ; and U.S. Pat. No. 11 ,135,025, all incorporated herein by reference. In particular, a localizer may be able to track an object within a volume relative to the subject. The navigation volume, in which a device may be tracked, may include or be referred to as the navigation coordinate system or navigation space. A determination or correlation between two coordinate systems may allow for or also be referred to as a registration between two coordinate systems.

[0041] In various embodiments, the first coordinate system, which may be a robotic coordinate system, may be registered to a second coordinate system, which may be a navigation coordinate system. Accordingly, coordinates in one coordinate system may then be transformed to a different or second coordinate system due to a registration. Registration may allow for the use of two coordinate systems and/or the switching between two coordinate systems. For example, during a procedure, a first coordinate system may be used for a first portion or a selected portion of a procedure and a second coordinate system may be used during a second portion of a procedure. Further, two coordinate systems may be used to perform or track a single portion of a procedure, such as for verification and/or collection of additional information.

[0042] Furthermore, images may be acquired of selected portions of a subject. The images may be displayed for viewing by a user, such as a surgeon. The images may have superimposed on a portion of the image a graphical representation of a tracked portion or member, such as an instrument. According to various embodiments, the graphical representation may be superimposed on the image at an appropriate position due to registration of an image space (also referred to as an image coordinate system) to a subject space. A method to register a subject space defined by a subject to an image space may include those disclosed in U.S. Pat. Nos. U.S. Pat. No. 8,737,708; U.S. Pat. No. 9,737,235; U.S. Pat. No. 8,503,745; and U.S. Pat. No. 8,175,681 ; all incorporated herein by reference.

[0043] During a selected procedure, the first coordinate system may be registered to the subject space or subject coordinate system due to a selected procedure, such as imaging of the subject. In various embodiments, the first coordinate system may be registered to the subject by imaging the subject with a fiducial portion that is fixed relative to the first member or system, such as a robotic system or other instrument. The known position of the fiducial relative to any portion, such as the robotic system or the subject, may be used to register the subject space relative to any coordinate system in which the fiducial may be determined (e.g., by imaging or detecting (e.g., touching)). Registration of a second coordinate system may allow for tracking of additional elements not fixed to a first portion, such as a robot that has a known coordinate system.

[0044] The tracking of an instrument during a procedure, such as a surgical or operative procedure, allows for navigation of a procedure. The navigation may be used to determine a pose of one or more portions, such as an instrument. The pose may include any number of degrees of freedom, such as a three-dimensional location (e.g., x, y, z) and an orientation (e.g., yaw, pitch, and roll). When image data is used to define an image space it can be correlated or registered to a physical space defined by a subject, such as a patient. According to various embodiments, therefore, the patient defines a patient space in which an instrument can be tracked and navigated. The image space defined by the image data can be registered to the patient space defined by the patient. The registration can occur with the use of fiducials that can be identified in the image data and in the patient space.

[0040] Fig. 1 is a diagrammatic view illustrating an overview of a procedure room or arena. In various embodiments, the procedure room may include a surgical suite in which may be placed a robotic system 20 and a navigation system 26 that can be used for various procedures. The robotic system 20 may include an appropriate robotic system, such as a Mazor X™ Robotic Guidance System, sold by Mazor Robotics Ltd. having a place of business in Israel and/or Medtronic, Inc. having a place of business in Minnesota, USA and/or as disclosed in U.S. Pat. No. 11 ,135,025, incorporated herein by reference. The robotic system 20 may be used to assist in guiding a selected instrument, such as drills, screws, etc. relative to a subject 30. In addition or alternatively, the robotic system 20 may hold and/or move various instrument such as an imaging system that may be an ultrasound (US) probe 33. The US probe 33 may be moved relative to a subject, such as a by a user as well. The US probe may be moved to achieve acquisition of selected image data.

[0041] The robotic system 20 may include a mount 34 that fixes a portion, such as a robotic base 38, relative to the subject 30. The robotic system 20 may include one or more arms 40 that are moveable or pivotable relative to the subject 30, such as including an end effector 44. The end effector may be any appropriate portion, such as a tube, guide, or passage member. Affixed to and/or in place of the end effector may be the imaging system that may be the US probe 33.

[0042] The end effector 44 may be moved relative to the base 38 with one or more motors. The position of the end effector 44 may be known or determined relative to the base 38 with one or more encoders at one or more joints, such as a wrist joint 48 and/or an elbow joint 52 of the robotic system 20. A robotic processor module 53 may be used to control (e.g., execute instructions) to move and determine a pose of the end effector, such as relative to the base 34. As discussed above, the robotic system 20 including the various portions may be operated to move each portion relative to the base 34. The pose of the base 34 may be known in a coordinate system, such as the patient space of the patient 30 and/or the image coordinate system due to a registration as discussed above and exemplary disclosed in U.S. Pat. No. 11 ,135,025, incorporated herein by reference. [0043] The navigation system 26 can be used to track the location of one or more tracking devices, tracking devices may include a robot tracking device 54, a subject tracking device 58, an imaging system tracking device 62, a tool tracking device 66, and/or an US probe tracking device 81 . All or one of the tracking devices may be generally referred to as a tracking device herein. US probe 33 may be used to acquire US image data of the subject 30 as may an imaging system 80, as discussed herein.

[0044] A tool or moveable member 68 may be any appropriate tool such as a drill, forceps, or other tool operated by a user 72. The tool 68 may also include an implant, such as a spinal implant or orthopedic implant. It should further be noted that the navigation system 26 may be used to navigate any type of instrument, implant, or delivery system, including: guide wires, arthroscopic systems, orthopedic implants, spinal implants, deep brain stimulation (DBS) probes, etc. Moreover, the instruments may be used to navigate or map any region of the body. The navigation system 26 and the various instruments may be used in any appropriate procedure, such as one that is generally minimally invasive or an open procedure.

[0045] The imaging device or system 80 may be an additional or alternative imaging system that may be used to acquire pre-, intra-, or post-operative or realtime image data of a subject, such as the subject 30. It will be understood, however, that any appropriate subject can be imaged and any appropriate procedure may be performed relative to the subject. In the example shown, the imaging device 80 comprises an 0-arm® imaging device sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colorado, USA. The imaging device 80 may have a generally annular gantry housing 82 in which an image capturing portion is moveably placed. The imaging device 80 can include those disclosed in U.S. Pat. Nos. 7,188,998; 7,108,421 ; 7,106,825; 7,001 ,045; and 6,940,941 ; all of which are incorporated herein by reference, or any appropriate portions thereof. It is further appreciated that the imaging device 80 may include in addition or alternatively a fluoroscopic C-arm. Other exemplary imaging devices may include fluoroscopes such as bi-plane fluoroscopic systems, ceiling mounted fluoroscopic systems, cath-lab fluoroscopic systems, fixed C-arm fluoroscopic systems, isocentric C-arm fluoroscopic systems, 3D fluoroscopic systems, etc. Other appropriate imaging devices can also include MRI, CT, ultrasound, etc.

[0046] The position of the imaging system 33, 80, and/or portions therein such as the image capturing portion, can be precisely known relative to any other portion of the imaging device 33, 80. The imaging device 33, 80, according to various embodiments, can know and/or recall precise coordinates relative to a fixed or selected coordinate system. For example, the robotic system 20 may know or determine its position and position the US probe 33 at a selected pose. Similarly, the imaging system 80 may also position the imaging portions at a selected pose. This can allow the imaging system 80 to know its position relative to the patient 30 or other references. In addition, as discussed herein, the precise knowledge of the position of the image capturing portion can be used in conjunction with a tracking system to determine the position of the image capturing portion and the image data relative to the tracked subject, such as the patient 30. [0047] Herein, reference to the imaging system 33 may refer to any appropriate imaging system, unless stated otherwise. Thus, the US probe 33 as the imaging system is merely exemplary regarding the subject disclosure. As one skilled in the art will understanding, generally the US probe 33 may emit a US wave in a plane and receive an echo relative to any portions engaged by the wave. The received echo at the US probe 33 or other appropriate received may be used to generate image data and may be used to generate an US image also referred to as a sonogram. The pose (e.g., distance from a selected portion of the US probe 33 and/or the tracking device 81) may be determined or predetermined and saved for recall with a calibration process and/or jig, such as that disclosed in U.S. Pat. Nos. 7,831 ,082; 8,320,653; and 9,138,204, all incorporated herein by reference.

[0048] The imaging device 80 can be tracked with a tracking device 62. Also, the tracking device 81 can be associated directly with the US probe 33. The US probe 33 may, therefore, be directly tracked with a navigation system as discussed herein. In addition or alternatively, the US probe 33 may be positioned and tracked with the robotic system 20. Regardless, image data defining an image space acquired of the patient 30 can, according to various embodiments, be registered (e.g., manually, inherently, or automatically) relative to an object space. The object space can be the space defined by a patient 30 in the navigation system 26.

[0049] The patient 30 can also be tracked as the patient moves with a patient tracking device, DRF, or tracker 58. Alternatively, or in addition thereto, the patient 30 may be fixed within navigation space defined by the navigation system 26 to allow for registration. As discussed further herein, registration of the image space to the patient space or subject space allows for navigation of the instrument 68 with the image data. When navigating the instrument 68, a position of the instrument 68 can be illustrated relative to image data acquired of the patient 30 on a display device 84. An additional and/or alternative display device 84’ may also be present to display an image. Various tracking systems, such as one including an optical localizer 88 or an electromagnetic (EM) localizer 92 can be used to track the instrument 68.

[0050] More than one tracking system can be used to track the instrument 68 in the navigation system 26. According to various embodiments, these tracking systems can include an electromagnetic tracking (EM) system having the EM localizer 94, an optical tracking system having the optical localizer 88 and/or other appropriate tracking systems not illustrated such as an ultrasound tracking system, or other appropriate tracking systems. One or more of the tracking systems can be used to track selected tracking devices, as discussed herein, sequentially or simultaneously. It will be understood, unless discussed otherwise, that a tracking device can be a portion trackable with a selected tracking system. A tracking device need not refer to the entire member or structure to which the tracking device is affixed or associated.

[0051] The position of the patient 30 relative to the imaging device 33 can be determined by the navigation system 26. The position of the imaging system 33 may be determined, as discussed herein. The patient 30 can be tracked with the dynamic reference frame 58, as discussed further herein. Accordingly, the position of the patient 30 relative to the imaging device 33 can be determined.

[0052] Image data acquired from the imaging system 33, or any appropriate imaging system, can be acquired at and/or forwarded from an image device controller 96, that may include a processor module, to a navigation computer and/or processor system 102 that can be a part of a controller or work station 98 having the display 84 and a user interface 106. The processor system 102 may be a processor module, as discussed herein, including integral memory or a communication system to access external memory for executing instructions and/or operated as a specific integrated circuit (e.g., application specific integrated circuit (ASIC)). It will also be understood that the image data is not necessarily first retained in the controller 96, but may also be directly transmitted to the work station 98. The work station 98 can provide facilities for displaying the image data as an image 108 on the display 84, saving, digitally manipulating, or printing a hard copy image of the received image data. The user interface 106, which may be a keyboard, mouse, touch pen, touch screen or other suitable device, allows the user 72 to provide inputs to control the imaging device 80, via the image device controller 96, or adjust the display settings of the display 84. The work station 98 may also direct the image device controller 96 to adjust the image capturing portion of the imaging device 80 to obtain various two-dimensional images along different planes in order to generate representative two-dimensional and three-dimensional image data. [0053] With continuing reference to FIG. 1 , the navigation system 26 can further include any one or more tracking system, such as the tracking system including either or both of the electromagnetic (EM) localizer 94 and/or the optical localizer 88. The tracking systems may include a controller and interface portion 110. The controller 110 can be connected to the processor portion 102, which can include a processor included within a computer. The EM tracking system may include the STEALTHSTATION® AXIEM™ Navigation System, sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colorado; or can be the EM tracking system described in U.S. Patent Application Serial No. 10/941 ,782, filed Sept. 15, 2004, and entitled "METHOD AND APPARATUS FOR SURGICAL NAVIGATION"; U.S. Patent No. 5,913,820, entitled “Position Location System,” issued June 22, 1999; and U.S. Patent No. 5,592,939, entitled “Method and System for Navigating a Catheter Probe,” issued January 14, 1997; all of which are herein incorporated by reference. It will be understood that the navigation system 26 may also be or include any appropriate tracking system, including a STEALTHSTATION® TREON® or S7™ tracking systems having an optical localizer, that may be used as the optical localizer 88, and sold by Medtronic Navigation, Inc. of Louisville, Colorado. Other tracking systems include an acoustic, radiation, radar, etc. The tracking systems can be used according to generally known or described techniques in the above incorporated references. Details will not be included herein except when to clarify selected operation of the subject disclosure. [0054] Wired or physical connections can interconnect the tracking systems, imaging device 80, etc. Alternatively, various portions, such as the instrument 68 may employ a wireless communications channel, such as that disclosed in U.S. Pat. No. 6,474,341 , herein incorporated by reference, as opposed to being coupled directly to the controller 110. Also, the tracking devices 62, 66, 54 can generate a field and/or signal that is sensed by the localizer(s) 88, 94.

[0055] Various portions of the navigation system 26, such as the instrument 68, and others as will be described in detail below, can be equipped with at least one, and generally multiple, of the tracking devices 66. The instrument can also include more than one type or modality of tracking device 66, such as an EM tracking device and/or an optical tracking device. The instrument 68 can include a graspable or manipulable portion at a proximal end and the tracking devices may be fixed near the manipulable portion of the instrument 68.

[0056] Additional representative or alternative localization and tracking system is set forth in U.S. Pat. No. 5,983,126, which is hereby incorporated by reference. The navigation system 26 may be a hybrid system that includes components from various tracking systems.

[0057] According to various embodiments, the navigation system 26 can be used to track the instrument 68 relative to the patient 30. The instrument 68 can be tracked with the tracking system, as discussed above. Image data of the patient 30, or an appropriate subject, can be used to assist the user 72 in guiding the instrument 68. The image data, which may include one or more image data or images, may be registered to the patient 30. The image data defines an image space that is registered to the patient space defined by the patient 30. The registration can be performed as discussed herein, automatically, manually, or combinations thereof.

[0058] Generally, registration allows a translation map to be generated of the physical location of the instrument 68 relative to the image space of the image data. The translation map allows the tracked position of the instrument 68 to be displayed on the display device 84 relative to the image 108. A graphical representation 68i, also referred to as an icon, can be used to illustrate the location of the instrument 68 relative to the image data 108.

[0059] With continuing reference to Fig. 1 , a subject registration system or method can use the tracking device 58. The tracking device 58 may include portions or members 120 that may be trackable, but may also act as or be operable as a fiducial assembly. The fiducial assembly 120 can include a clamp or other fixation portion 124 and the imageable fiducial body 120. It is understood, however, that the members 120 may be separate from the tracking device 58. The fixation portion 124 can be provided to fix any appropriate portion, such as a portion of the anatomy. As illustrated in Fig. 1 , the fiducial assembly 120 can be interconnected with a portion of a spine, such as a spinous process 130 (Fig. 2). The fixation portion 124 can be interconnected any appropriate portion that is selected to be tracked. In various embodiments, the fixation portion 124 may be connected (e.g., fixed in a rigid and immovable manner (such as moving less than 0.5 mm) with a spinous process 130 in any appropriate manner. For example, a pin or a screw 131 can be driven into the spinous process 130. Fiducial portions may also include one or more portions of the subject that may be imaged, such as boney portions.

[0060] As illustrated in Fig. 1 , the US probe 33 may be positioned relative to the subject 30, such as by the robotic system 20. As discussed herein, therefore, the robotic system 20 may move the US probe 33 to a selected position relative to the subject 30. According to various embodiments, the US probe 33 may be positioned relative to the subject in any appropriate manner. For example, the user 72 or a second user may move and/or hold the US probe 33.

[0061] According to various embodiments, the ultrasound probe may emit or transmit ultrasound waves in a selected pattern or plane, as is understood by one skilled in the art. The plane may be a shape as is understood by one skilled in the art. The plane is generally able to acquire data in a field of view to generate images, also referred to as sonograms when images are generated based on ultrasound data. The image data collection plane and/or its pose may be determined or known relative to the US tracking device 81 , as discussed above.

[0062] It is understood herein that images generated from image data may be two-dimensional (2D), three-dimensional (3D), four dimensional (4D, i.e., images over time), or combinations thereof. Thus, the registration may occur between any selected one of these as well. The number of points and/or other registration portions (e.g., features or structures) required or selected for registration is generally understood by one skilled in the art. The registration, however, may be multimodal such that a plurality of types or data, features, etc. may be used to generate a registration between at least two images including the related image data.

[0063] Further, image data and related or generated images may be collected and displayed in any appropriate manner. For example, image data may be collected and an image may be displayed based thereon in substantially real time. Real time may include a time difference between collection of image data and a display of an image based thereon of less than five seconds, including less than 4, 3, 2, 1 seconds or any appropriate increment of time including about 0.1 seconds to about 10 seconds. For example, the US probe 33 may be positioned to image the subject and the image (e.g., sonogram) displayed 150 in less than five seconds from when the image data is collected. Real time may include a time differential which allows the user to understand the current condition of the subject even if the condition is changing, such as imaging a heart beat, flow of blood in vessels, etc. As discussed herein, an augmented image may be generated at a same rate. Thus, pre-acquired image data may be inpainted (e.g., added as a graphical representation, added image data form a second source, etc.) onto a real time image or an augmented image may be generated including pre-acquired or alternative image data and a real time image data.

[0064] As discussed above, the patient tracker or DRF 58 may be connected to the patient 30, or other appropriate subject in an appropriate manner. Initially, it is understood that the subject 30 need not be a human patient or other living patient, but may be an inanimate object that includes internal structures to which the tracker 58 may be connected. In various embodiments, a plurality of the DRF 58 may be connected to a plurality of elements within the subject. For example, the DRF 58 may include a plurality of trackers at least one tracker 58 is connected to a spinous process 130 of a vertebra, such as in L4 vertebrae 200 as illustrated in Fig. 2. It is understood that various subjects, such as the subject 30 may include a plurality of vertebrae within a spine. Therefore, a second vertebra, such as an L5 vertebra 204 may also have a DRF or tracker 208 connect thereto. The patient tracker 208 may be substantially identical to the patient tracker 58 such that a plurality of the patient trackers may be connected to the subject 30 simultaneously. Each of the patient trackers may be individually identified to allow for a tracking of the individual trackers 58, 208 related to individual vertebrae 200, 204. It is understood that each vertebrae that is selected to be tracked may be tracked with an individual tracker and that two are merely exemplary. Each of the trackers 58, 208 may include a trackable portion (e.g., one or more coils), a portion to be connected to the subject member or portion (e.g., vertebra). The trackable portion or some other portion of the tracker 58, 208 may be used to specifically identify the tracker based on a signal from the tracker 58, 208.

[0065] Further, the image 108 may be segmented such that each of the vertebrae illustrated in the image 108 may be tracked and have its position updated based upon one or more of the trackers 58, 208. For example, the image 108 may include an image of a plurality of vertebrae. One or more of the vertebrae may be segmented, as understood in the art. The segmented portion may be used to identify at least one portion of the subject to which one or more of the trackers is connected and may be uniquely identified. Segmentation and various tracking systems may include those disclosed in U.S. Pat. No. 11 , 426,242, incorporated herein by reference.

[0066] As noted above the tracking portion may be connected to the respective element, such as the vertebra 200, 204 with a connector 131. The connector 131 may include a screw, pin, or other appropriate member to selectively connect to the tracking device 58, 208 to the vertebra. In various embodiments it is selected to have the tracking device fixed to the vertebra in a selected pose (including a location and an orientation). Therefore, movement of the tracking device from the selected pose relative to the vertebra may be unselected and/or cause for a lack of accuracy of the tracking and navigation. In various embodiments, this unselected movement may be undesirable. According to various embodiments, including those discussed herein, the navigation or tracking system may provide an alert to the user that the tracker may have (e.g., within a selected determined probability) become detached or unfixed relative to the subject. According to various embodiments, the detection may be substantially automatic and allow for an output when the tracking device, such as the tracking device 58, 208 has become detached or moved from a predetermined or preselected pose.

[0067] According to various embodiments an alert may be provided to the user 72. For example an audio or visual alert may be provided to the user 72. A visual display on the display device 84 may be the alert. Further an audio alert may be emitted to alert the user to a detection of a probable detachment of the tracking device. Other alerts may include a haptic feedback, such as through vibration of the instrument 68 or other appropriate haptic feedback. In various embodiments, the display 84 may stop such that no display is made or an indication is made that tracking of the subject 300 has stopped and that the last image displayed is the last updated image of the pose of the vertebrae or portion of the subject prior to the detection of the detachment of the tracking device. Any one or more alerts may be provided.

[0068] Accordingly, the tracking device may be initially connected to the subject 30 in an appropriate manner. As discussed above the tracking device, such as the tracking device 58, 208, may be connected to one or more of the vertebrae 200, 204. The tracking device may be provided as a single member with the connector 131 and/or may be provided as a separate or removable member from the connector 131. Regardless the selected tracking device may be connected to a selected portion of the subject 30, such as one or more of the vertebrate 200, 204.

[0069] With reference to Fig. 2, the navigation system 26 may have a predetermined range of motion of the portion on which a procedure may occur. Generally the procedure may occur on one or more portions to which the tracking device 58, 208 is connected. For example, a procedure may occur between the vertebrae 200, 204. Therefore, a known or plausible range of motion may be predetermined and recalled by the navigation system. The ranges of motion may include a disc height restoration, segmental deterioration that may be corrected such as lordosis correction, coronal deformity correction, or other possible surgical or corrective procedures. The type of procedure may be selected by the user 72 and the system may recall the possible or plausible motions. Additionally or alternatively, the user may input possible or plausible motions during a procedure. The possible or plausible motions may be based upon prior procedures, predetermined and stored based upon literature review, based upon a specific plan for the subject 30 (e.g., based upon prior acquired planning including images), an assessment of patient images (e.g., automatic or by the user), a training procedure such as for the specific procedure on the subject 30 or in general, and value is based upon the case specific or patient specific procedure.

[0070] During a procedure the navigation system 26 may be operated to detect motion of one or more of the vertebrae based upon the tracking of the tracking device. For example, a first detected motion between a first pose 210 and a second pose 214 may be determined to be acceptable such as including a translation of a selected threshold from the first pose 210. The threshold may be any appropriate amount, such as those discussed above based upon various inputs. Thresholds may include a maximum translation value, such as 2 centimeters (cm) in any direction. In various embodiments, the system may track a change in pose from the initial pose 210 to a second pose 216 and determine that the translation is greater than a threshold. If the determined translation is greater than a threshold the system may identify that the tracking device 208 has possibly or probably become detached and provide the alert to the user 72, as discussed above.

[0071] In addition or alternatively, two translation movements may be tracked with or separate from one or more rotational movements. For example, as illustrated in Fig. 3, a movement from the initial pose 210 to a second pose 220 may include a rotation or angle of movement as illustrated by arrow 224 may be determined to be acceptable. A rotational motion, as illustrated in Fig. 3 such as between an initial pose 210 and a second pose 228 may be determined to be greater than a threshold. According to various embodiments the threshold rotational change may be about 5°, about 10°, or about 15° around any selected angle or arc length. Again, as noted above, the threshold rotational change may be based upon various inputs including user inputs or recalled inputs based upon prior performed procedures. If the navigation system 26 determines that the rotational change is greater than a threshold an alert may be made to the user 72. Again, the thresholds may be based upon plausible or possible changes and may be input by the user 72 for a specific subject or in general and/or may be recalled from a database during a procedure based upon an input procedure.

[0072] The navigation system 26 may also have built in or accessible rules or parameters regarding various limitation of the subject 30 that are regarding where the tracking devices are connected. The limitations may include the rigidity of one or more bones, the rigidity between two or more bones (e.g. the vertebrae 200, 204), or other appropriate interactions. This may include a maximum translational and/or rotational amount, similar to that discussed above. This may further include various anatomical or other structural configurations such as the inclusion of a spinal cord and its various maximum dimensional changes, such as curvature or elongation. Again the types of movements or amount of movements or thresholds may be input or recalled from selected sources, such as from a database or the user and may be recalled automatically or manually. The amount of movement may be based upon a vertebral shift when a device is positioned between a vertebrae and the amount of movement that may be expected or determined at one vertebrae when a device is positioned at another. In an example, the amount of movement may be inversely proportional to the distance from the device. Thresholds may include that a spinal cord may have a limited or desirably limited amount of movement relative to the vertebrae including an elongation or curvature thereof. Further that the two or more portions, such as bones, may not intersect or may not likely intersect during a procedure. Any one or more of these types of motions may be determined as a possible detachment of the tracking device and an alert may be provided.

[0073] For example, with reference to Fig. 4, the tracking devices 58, 208 may be connected to the respective vertebrae 200, 204. A first translational amount of movement, such as between a first position 210 and a second position 214 may be determined to be acceptable. However, if the two vertebrae 200, 204 become substantially in contact or are determined so based upon tracking of the respective tracking devices 58, 208 an alert may be provided as contact may be input or determined to be implausible. Therefore, if the tracking device is tracked that the vertebrae 200, 204 move from an initial position 232 to a new tracked position 236 an alert may be provided. As illustrated in Fig. 4, the second tracked position 236 may include or report contact between the two vertebrae 200, 204. During a procedure, such as a disc replacement, contact between adjacent vertebrae may generally be implausible or infeasible. Therefore if tracking of the tracking devices 58, 208 determines the contact of the vertebrae 200, 204 an alert may be made that the tracking device 58, 208 may be detached.

[0074] With reference to Fig. 5, the two vertebrae 200, 204 may be understood to have a spinal cord 240 positioned relative thereto. The spinal cord 240 may have or may feasibly have a selected geometry, such as a large radius 244. The radius or the curve of the spinal cord may be understood to be a cross- sectional radius of the spinal chord in the spine. The spinal cord 240 position may be determined based upon a range of motion of the tracking device 208 due to motion of the vertebrae 204. The known position of the spinal cord 240 is between the vertebrae 200, 204 and the tracked pose of the vertebrae 204 from a first pose 210 to a second pose 246 may be determined to be acceptable due to the assumed radius of the spinal cord 240. However if the spinal cord 240 is determined to possibly have at least one sharp bend or small radius portion or segment 250, such as due to a tracked pose of the vertebrae 204, to a pose 254 a determination that the tracking device 208 has probably become detached may be made. Again that the determination may be that the spinal cord 240 has an angle or radius that is beyond a threshold, such as smaller than a selected radius or having an angle between two portions smaller than a selected threshold may be used as a threshold for the determination of a probable detachment of a tracking device. The navigation system 26 may track the tracking devices 58, 208 during a procedure and continuously check at a selected rate for the infeasible or implausible motions or positions, such as contact of vertebrae or angles of a spinal cord, to determine possibility of a detachment of one or more of the tracking devices. [0075] Turning to reference to Fig. 6, a threshold regarding various time derivatives may also be made. Derivatives may be used to determine a velocity or a force or acceleration of one or more of the tracked portions. The derivatives may be based upon the displacement values, such as the linear or angular displacement as discussed above, or provide a further mathematical refinement thereof. Again threshold values may be determined such as recalled from a database or input by the user. Further maximum thresholds or maintained value thresholds may be used to determine acceptable or unacceptable values that may relate to a probably detached tracking device.

[0076] A large acceleration or force or a selected acceleration or force over time may be used to determine a possible detachment of the tracking device. For example, an acceleration or force greater than a human is likely to achieve may be determined or used as a threshold value. In various embodiments, the determination of a force may be based upon a known or estimated value of inertia of a tracked portion, such as the density of bone or known or determined mass, including a density of vertebrae or plurality of vertebrae. Further an estimation or determination of a mechanical advantage of various tools or instruments used during a procedure and/or identification of a tool (e.g., automatically) by a tracking or input by user, may be used to determine a possible range of forces and velocities that may be achieved.

[0077] The vertebrae 200, 204 may have the respective tracking devices 58, 208 associated there with. As illustrated in Fig. 6 the vertebrae 204 may have an initial tracked position 260 and a second track position 264. The difference between the positions 260, 264 may be a selected translational or rotational movement such as a change in position of about 5 millimeters (mm). The change in distance of about 5mm over 5 seconds may include a determination of a velocity of about 1mm per second. However, if the distance change of 5mm over a time of about 0.1 milliseconds may lead to a determination of a velocity about 50 meters per second. A threshold may be pre-selected or determined such that a determination that a velocity greater than a selected threshold, such as greater than about 1 meter per second may be unrealistic or implausible and an alert may be provided. Again the threshold velocity may be input or determined in the appropriate manner.

[0078] Similarly or alternatively, a force value may be determined. For example, the further derivative of the velocity over a selected time may be used to determine a force. For example if the velocity changes by 10mm per second over one second such that an acceleration is 10mm per second squared a force of about 0.0002 Newton may be determined. However, if the velocity changes by about 1 m per second over a period of time of about 0.02 milliseconds an acceleration may be determined to be about 50,000m per second squared and may be calculated to a force of about 1000 Newtons. This may be based upon a determination or an assumption of a mass of the portion being moved, such as about 20 grams per vertebra. Again a force threshold may be determined such that a force of greater than about 1 Newton may be a selected threshold. If the selected force threshold is surpassed a notice may be provided to the user that the tracking device may be detached. [0079] The navigation system 26 may include a plurality of tracking systems and/or may track a plurality of tracking devices. The plurality of tracking devices may include the tracking devices associated with the subject 30, including the tracking devices 58 and 208, and also the tracking device 66 associated with the instrument 68. The instrument 68 may be tracked by the EM tracking system or any appropriate tracking system and/or the optical tracking system including the optical localizer 88. Regardless of the tracking system configured to track the tracking device 66 associated with the instrument 68, the navigation system may track or determine the pose of the instrument 68 with the associated instrument tracking device 66. This allows the navigation system 26 to determine that the instrument 68 is or is not positioned near or adjacent one or both of the vertebra 200, 204 and/or may effect a pose of one or more of the vertebrae or any selected portion of the subject 30.

[0080] If the navigation system determines that the vertebra moves from an initial pose 270 to a second pose 274 while the instrument 68 is near the vertebra 204 the navigation system may determine that the movement of the vertebra 204 is plausible. The amount of movement, such as for translation or rotation may also be determined as a threshold value based upon the instrument 68. For example, navigation system 26 may determine or recall that the maximum or threshold movement may be less than about 5mm, 2mm, or any appropriate amount. Therefore, as long as the movement between the pose 270 and pose 274 for the vertebra 204 is within the threshold and the instrument 68 has been determined to be present the movement may be determined to be plausible and no alert may be provided.

[0081] However, if the vertebra 204 is determined or tracked to move from the first pose 270 to the second pose 274 when no instrument is tracked, the navigation system 26 may determine that a possible detachment of a tracking device has occurred. Again the optical localizer 88 or any appropriate tracking device or localizer may be used to track the instrument. Therefore, the instrument to be tracked and determined not to be present near or adjacent to either of the vertebra or any portion that may cause the vertebra 204 to move.

[0082] If the determination is that an instrument is not near a portion that has moved, a determination of a possible detachment of the tracking device may be made. Further, as discussed above, various tracking devices may be associated with one or more of the portions of the subject 30. Therefore if the vertebra 204 is determined to move in an implausible manner the tracking device 208 may be determined or alerted to possibly be detached. The navigation system 26 may determine a probable or possible tracking device that has become detached. Therefore, if the vertebra 200 has been determined to move in only a plausible manner the system, including the navigation system 26, may not alert that the tracking device 58 has possibly become detached.

[0083] Turning to reference to Fig. 8, the tracking device, such as the tracking device 208 associated with the vertebra 204 may be tracked. The navigation system may, therefore, determine or track movement of the vertebra 204 from the first pose 280 to a second pose 284. The amount or type of movement may be determined to be related to a possible movement of the vertebra 204, at least, as discussed above. The tracking device 208 may have selected or known possible detachment modes. For example, the tracking device 208 may move in the direction of arrow 290 towards the vertebra 204. Therefore, if the tracking device is sensed to move in a direction that would determine that the vertebra 204 is moving generally in substantially straight line such as from a first pose 294 to a second pose 298 a determination of a possible detachment may be made. That is that the tracking device 208 may have become detached if the navigation system determines that the motion detected is unlikely and generally in the direction of a detachment mode of the attachment of the tracking device 208 to the vertebra 204.

[0084] A further detected motion may be a rotation of the vertebra 204 that is unlikely or generally implausible based upon the anatomy or constraints of the subject 30. For example, the vertebra 204 maybe tracked to rotate around an axis of the connection member generally in the direction of the arc 300. The rotation of the vertebra 204 may be implausible, but the rotation may be a known or recalled detachment mode or motion of the tracking device. Thus, if detected motion is rotation an alert that the tracking device 208 may have become detached may be made. Further, a pivoting of the vertebra 204, particularly above a threshold amount and/or in a reciprocating manner, may also be used to determine that the tracking device 208 has become detached from the vertebra 204. Determining movement along the arc or around the arc 304 may be used to evaluate or make a determination that the tracking device 208 may have become detached. [0085] An alert may be provided if motion is predominantly consistent with a known mode of detachment; e.g., for a spinal segmental tracker, the motion is predominantly a translation along and/or a rotation about the axis of the screw, suggesting that the screw is pulling out, advancing, and/or turning unexpectedly; and proportional to the distance from the screw tip, suggesting the tracker is pivoting about the tip. For an ENT patient reference, the motion is predominantly a translation parallel to or a rotation in the plane of the adhesive, suggesting the skin and therefore tracker is being pulled relative to the bone.

[0086] Motion may be expressed in any appropriate coordinate system, with knowledge (as by design or factory calibration) of the tracker’s mechanical features transformed (as by localization) into that coordinate system. Displacements of query points that are: significantly parallel to the screw axis suggest translation (slippage) along the shaft, not parallel to the screw axis but are well-fit by cylinders centered on the screw axis suggest rotation about shaft, and well-fit by spheres centered on the screw tip suggest pivoting about the tip. Motion may also be expressed relative to the tracker’s original pose and determined by inspecting the transformation’s translational and rotational components. A dominant rotation component whose axis is very near the screw axis in tracker coordinates suggests rotation about the shaft, and a dominant translation component whose direction is parallel to the screw axis in tracker coordinates suggests translation (slippage) along shaft 131 .

[0087] With reference to Fig. 9, the tracking devices 58, 208 are associated with respective vertebrae 200, 204. The tracking device may be tracked by any appropriate tracking system, such as the EM tracking system, including the EM localizer 94. Therefore, the tracking system including the EM localizer may track a movement or changed pose of the vertebrae 204 from a first pose 320 to a second pose 324.

[0088] Associated with one or more of the vertebrae may be an additional tracking or fiducial assembly, such as a fiducial array 330. The fiducial array 330 may include one or more fiducial markers or tracking points, such as one or more of an optical tracking portion 334. The fiducial array 330 may also be fixed relative to the vertebra 204 in appropriate manner, but may be separate from with the tracking device 208. Therefore, both of the tracking device 208 and the fiducial assembly 330 would move with the vertebrae 204 if the vertebrae moves.

[0089] An imaging system may include optical or light imaging system 340. The light imaging system may be any appropriate camera system, such as a charge coupled device, CMOS sensor, or the like. A signal from the camera assembly 340 may transmit an image (e.g., a picture) of at least to the vertebrae 200, 204 to the navigation system 26. An image may be acquired of the same portions to which the tracking devices 58, 208 are attached. Therefore, in a certain situation the camera 304 may view or capture an image of the vertebrae 204 moving from the first pose 320 to the second pose 324. The camera 340 may acquire an image directly of vertebrae 200, 204 or of a portion associated with the vertebrae such as the tracking device is 58, 208 or the fiducial array 330. In various embodiments, the fiducial array 330 may be configured to be readily identifiable by the camera 340 such as by emitting or reflecting lights in a high contrast manner, such as in the selected color or wavelength.

[0090] If the camera 340 acquires an image that identifies a change in pose similar to the tracked pose change then the navigation system 26 may not provide an alert to the user of 72. Thus, the camera 340 may provide a backup or confirmation of a change in pose of the vertebrae 204.

[0091] In various situations, however, the tracking system may track a change in pose of the vertebrae 204 from the first pose 320 to the second pose 324. Again the fiducial array 330 may be associated with the vertebra 204 and would also move. The camera system 340 may also capture an image of the vertebra 200, 204. The image 340 may not include a change in pose of the vertebra 204 from the pose 320. The fiducial array 330 may be included in the image or used for identification, or only the image of the vertebra 204 may be imaged. Thus, if the image from the camera 340 does not match the tracked pose of the tracking device 208 an alert may be provided to the user that the tracking device may be detached. Thus, the camera system 340 may provide additional signals for determination or confirmation of movement of one or more of the portions and/or maintaining attachment of the tracking devices 58, 208. Further, it is understood that each of the portions that include a tracking device may also include one or more of the fiducial arrays 330 and including only one or any of the fiducial arrays 330 on the vertebra 204 is merely exemplary for ease and clarity of the current discussion. [0092] Turning reference to Fig. 10, the tracking device 58 is illustrated in greater detail. The tracking device 58 may include the connection portion or stem 131 and a sensor portion 350. The sensor portion 350 may be an EM coil assembly, optical array, or any appropriate sensor assembly to be sensed by one or more of the tracking systems. Therefore, the tracking device 58 may be tracked with a selected tracking system.

[0093] Included or associated with the tracking device 58, however, may also be additional sensors. For example, a force sensor 354 may be associated with the tracking device 58. Additionally and/or alternatively, a torque sensor 358 may also be associated with the tracking device 58. The sensors, such as the force sensor 354 and the torque sensor 358 may sense a force or torque applied to or relative to the tracking device 58. For example, the tracking device may be torqued into the vertebra 200 in a selected manner and at a selected time.

[0094] The sensors 354, 358 may transmit a force and/or torque signal. The force or torque signals may be received by the tracking system to allow for a determination or measurement of an absolute value or relative value of a force or torque associated with the tracking device 58. If the force or torque is sensed in a selected manner and/or at a unexpected time a determination that the tracking device 58 has become detached may be made. For example, it is understood that the tracking system may sense that a force or torque may be sensed when the tracking device 58 is being inserted into the subject 30, such as into the vertebrae 200. However, if a force or torque is sensed during a navigated portion of the procedure the tracking system or navigation system 26 may provide a signal that the tracking device 58 may be detached.

[0095] Further, a specific type of force or torque curve may be sensed and evaluated to determine a possible detachment. For example, if an initial force or torque curve 360 is sensed followed by a lower sensed force or torque 364 and/or followed by a minimal force or torque 368 measurement the navigation system 26 may determine that the tracking device 58 is possibly detached partially or completely from the subject, such as the vertebrae 200. If the determination is that the tracking sensor may be detached, the alert may be provided to the user 72, as discussed above. Therefore, the force and torque sensors 354, 358 may sense and alert the user 72 to rotational or translational movement and/or associated forces to assist to make a determination that the tracking device 58 is attached or detached.

[0096] Turing reference to Fig. 11 , a vertebra, such as the vertebra 204 may have the tracking device 208 associated or connected thereto, as discussed above. Also associated with the vertebra 204 may be one or more additional sensors in addition to those discussed above or alternative to those discussed above. Sensors may include an accelerometer sensor 380, a gyroscope 384, combinations thereof, only one or the other. The one or more sensors may be provided together in an inertial monitoring unit (IMU) and/or separately. The accelerometer 380 and gyroscope 384 may be used to determine an acceleration, speed, or change in position of the vertebra 204. [0097] For example, the tracking device 208 may be used to track the vertebra 204 and a change in pose from a first pose 390 to a second pose 394 may be tracked. The change in pose may be based upon a tracked pose of the tracking device 208. In addition, the gyroscope and the accelerometer 384, 380 may be used to track or sense a linear acceleration, velocity, or change in position or an angular acceleration, velocity, or change in angle. Therefore, a linear acceleration or an angular velocity or their time integrals may be used to determine whether the change in pose 394 of the vertebrae 204 matches the tracked pose or its time derivatives by the tracking device 208. In other words, the accelerometer 380 may measure linear acceleration and the gyroscope 384 may measure angular velocity. The tracking device, such as the tracking device 208, may measure pose (e.g., position and orientation). Thus, derivatives may be determined of the tracked pose of the tracking device 208 can be compared directly to the data or measurements from the accelerometer sensor 380 and the gyroscope 384 and/or an integration of the accelerometer sensor 380 and the gyroscope 384 data and compared directly to the change in the tracked pose of the tracking device 208.

[0098] It is understood that the accelerometer and gyroscope 380, 384 need not be as sensitive (e.g., not having a sensitivity or accuracy of less than or equal to 0.1 mm per second squared). Rather the additional sensors 380, 384 may be provided to identify in a more gross sense whether the vertebrae 204 has moved from the first pose 390 to the second pose 394. If the additional sensor 380, 384 agree with the movement sensed by the tracking device 208 the navigation system 26 may not alert the user 72 that the tracking device has probably detached.

[0099] The vertebrae 204 may have the sensors associated therewith including the accelerometer and the gyroscope 380, 384. The tracking device or navigation system may determine or sense that the vertebra 204 has moved from the first pose to 390 to the second pose 394. The gyroscope and accelerometer 384, 380 may disagree or not sense the similar movement. If the additional sensors 380, 384 cannot sense the similar movement the navigation system may provide an alert to the user 72 of a probable detachment if the sensors 380, 384 do not match.

[00100] Thus, the additional sensors 380, 384 may be used to assist in determining whether the tracking device 288 remains attached by providing a signal to the navigation system 26. If the signal match were similar to the tracked pose based upon the tracking device, the alert may not be made. If a significant difference (e.g., threshold amount) is sensed or determined the alert may be made. The threshold amount may be any appropriate amount, such as a disagreement of 5%, 15%, 30%, or any appropriate disagreement threshold to provide an alert.

[00101] The one or more sensors may be provided as a unit such as an inertial measurement unit (IMU) which may include both a linear accelerometer and a gyroscope sensor. The IMU may be provided as a single unit it, and it is also attached separately to the vertebra 204. Further, it is understood that the IMU or individual sensors may be attached to any appropriate vertebra. [00102] Turning reference to Fig. 12, the tracking device 58 may be connected to the vertebra 200, as discussed above, such as with a post or fixation portion 131 . In addition to the fixation of the tracking device 58 may be an additional switch or switch assembly 410 may be provided. The switch 410 may include a switch portion and/or a signal generator 414 associated with the tracking device 58. A conductive member or portion 418 may extend from the switch portion 414 to the vertebrae 200. The conductive portion 418 may be formed of a fragile or delicate material, such as a thin metal wire or other conductive portion.

[00103] During an attachment of the tracking device, the conductive member 418 may be connected and a signal may be transmitted therethrough. If the signal is transmitted therethrough, a relatively low resistance may be measured for determination that the wire 418 is connected. The resistance may be any appropriate amount such as about 0 to about 10 ohms, or below any appropriate or set threshold amount.

[00104] If the tracking device 58 moves from the initial or nominal position, however, the connective portion 418 may form a break or disconnection 422. When the disconnection occurs the resistance in the wire portion 418 may increase, such as being substantially infinite. Therefore, an open circuit may be sensed and a signal may change from the switch member 414 to indicate that the circuit is open. On a detection of the open circuit or a resistance above a selected threshold, a signal may be provided to the navigation system 26 to alert the user 72 of a probable detachment of the tracking device. Therefore, the wire 418 may provide a physical switch or connection separate from the tracking device 58, but adjoined with the tracking device 58 to identify a selected movement such as a rotation, angular, or translational movement of the tracking device 58 relative to the vertebrae 200.

[00105] Turning reference to Fig. 13, the tracking device 58 may be associated with the vertebra 200 in a manner similar to that discussed above. A switch 440 may be included with the tracking device 58 including a switch or signal portion 444. A first connector 448 may extend from the switch portion 444 to the vertebrae 200. Again a signal may be transmitted through the connector or connective portion 448. The vertebra 200, the connector 131 , or a wire portion associated with the connector portion 131 may provide the return circuit. Therefore, rather than having a single complete circuit a single wire member 448 may extend from the tracking device 58 separate from the connector 131. The separate connector 448 may again be a small or fragile or thin gauge conductive member that may provide a single point of contact with the vertebrate 200 rather than requiring more than one. The nominal or connected resistance, however, may be greater than that noted above and a threshold amount may be 100 ohms or a determined appropriate amount that may be more or less.

[00106] Nevertheless, the wire 448 may form or have a break 452 occur if the tracking device 58 moves from an initial or selected position. The breaking of the wire or connector 448 may again cause a high resistance, such as greater than the threshold value selected for the switch system 440. When the resistance threshold is reached, the switch portion of 444 may transmit the signal to the navigation system 26. The navigation system may then provide the alert that a probability that the tracking device has detached may be made. The switch may provide a physical connection with the vertebrate 200 and further provide an indication when the tracking device 58 has moved from an initial or selected position such as due to rotation, translation, or angular movement. The change in resistance may be associated with an open circuit and a signal may be transmitted based thereon.

[00107] Turning reference to Fig. 14 the tracking device 58 may again be associated with the vertebra 200 with the connector 131. A switch assembly 460 may also be associated with the tracking device 58 that includes a switch or transmission portion 464 and a selector switch or member 468. In a nominal or operating position, the switch selector 468 may be pressed into the switch sensor or body 464. The switch body 464 may include a pressure sensor, spring, or the like to sense a contact of the switch member 468 with the vertebra 200.

[00108] When the tracking device 58 has become detached or moves relative to the vertebra 200, a distance 472 may exist or occur between the switch member 468 and the vertebra 200. Thus, a contact of the switch member 468 with the switch body 464 may stop. Also a movement of the tracking device 58 may change a force of the switch member 468 on the switch body 460 to also identify a possible detachment or movement of the tracking device 58 from an initial or selected position. The switch assembly 460 may include additionally or alternatively the switch member 468 that may physically contact the vertebra 200 to allow for a determination that the tracking device 58 is in a selected position and have reduced or no contact by sensing of pressure at the switch member 468 when the tracking device 58 is moved from a selected position. The signal may be sent from the switch to the navigation system 26 to allow the alert to be made that the tracking device has probably detached.

[00109] Turning to Fig. 15, a process 500 is illustrated. The process 500 may be executed by the processor module 102 or any appropriate processor module. Therefore, the process 500 may be included in an algorithm as instructions that are executed by the processor module. The process 500 may have incorporated a machine learning system to assist in determining a probability that the tracking device has become detached and provide the alert to the user 72.

[00110] The process 500 may begin in start block 504. The process then may access a current tracked posed of one or more trackers in block 508. Again, as discussed above, the respective tracking systems may track the poses of one or more of the tracking devices 58, 208 and provide the tracking information and pose information to the navigation system 26. Therefore, the processor module 102 may access the current tracked posed of any one or more of the trackers. The process 500 may then recall selected previous poses of one or more trackers, such as the same trackers accessed in block 508 in recall block 512.

[00111] A determination of a difference between a current pose and a previous pose may be made in block 516. The determination of a difference may be a determination of a translation difference, an angular difference, a rotational difference, or the like. Thus, the difference may be a change in pose from the current tracked pose to a previous tracked pose of any one of the respective tracking devices. This may be performed for one or more of the tracking devices that are tracked. A comparison may be made between the determined difference in a machine learning model 520. Alternatively, the tracked or determined poses may be provided directly to the machine learning model and the model may determine differences and whether or not the determined differences suggest detachment.

[00112] The machine learning model or learned model may be based upon any appropriate data. For example, a plurality of training data may be acquired in a lab setting or controlled setting where data sets are tagged or identified with identifiers such as “attached” or “detached”. The system may evaluate the respective tagged data sets. This may be used to train an appropriate machine learning system. Additionally or alternatively, case data may be provided for the learning or training data as well. Training data may be collected from users who have identified whether a tracking error occurred, detached tracking device occurs, or the like during an actual navigation event. The data may be collected and used for training in an appropriate manner. Various machine learning systems may include convolutional neural networks, recurrent neural networks, transformer systems, random forest algorithms, or other appropriate machine learning algorithms. The machine learning algorithm may be trained on the training data and then may be implemented or recalled in block 520.

[00113] Based upon a comparison of the ML model to the determined difference, a determination of a probability detachment is made in block 524. The machine learning model may be used to determine a probability of whether or not one or more of the tracking devices has become detached in block 524. The probability is based upon the machine learning model and the training data and the determined difference from block 516.

[00114] The process 500 may then output the probability in block 528. The output probability may then be determined as whether it is greater than a threshold or not in block 532. If the probability is not greater than a threshold a no path 534 may be followed to determine whether navigation is continuing in block 536. If navigation should continue a yes path 538 is followed to again access current tracked pose in block 508 and continue through the process 500. Therefore the process 500 may be an iterative process to continue determination of whether the tracking devices remain attached or have become detached.

[00115] If a probability that a detachment has occurred is greater than a threshold in block 532, a yes path 550 may be followed. The yes path may output an alert in block 554. The output alert in block 554 may be provided to the user 72, such as in the manner as discussed above. Therefore the user may be alerted to a probability of a detachment based upon the machine learning model and the comparison of block 520.

[00116] Again, a determination of whether navigation is continuing is made in block 536. If navigation is continuing, the yes path 538 is followed as discussed above. If navigation is not continuing, a no path 560 may be followed and the process 500 may end in block 564. The ending of the process 500 may include that further steps or processes occur, such as those carried out by the user 72. For example a procedure may continue without navigation or with navigation of different elements or other appropriate procedural steps. [00117] Therefore, the tracking of one or more tracking devices may be used a during procedure. As discussed above one or more systems or processes may also be used to determine a probability of whether a tracking device has become detached, such as one or more associated with the subject 30. The various processes or systems discussed above may be used individually, in combination, or alternatively to one another in a procedure. For example, a plurality of the processes systems may be provided in a single procedure and they may be used sequentially, individually, or in combination at any appropriate time.

[00118] Turning to reference to Fig. 16, a process 600 may be used to alert a user regarding a status of one or more tracking devices. The process 600 may be for performing a procedure with a detachment alert system. The process 600 may begin in block 604. Again, similar to the process 500 discussed above, the process 600 may be included in instructions that are executed by the processor module 102. As discussed above, one or more systems or methods may be used to determine whether a detachment of the tracking device has occurred. The system or process 600 may first determine whether a detachment alert is present in block 608. The detachment alert may be based on the one or more systems or processes as discussed above. Thus, the navigation system 26 may include or determine whether an alert is present or occurring.

[00119] If no detachment alert is present, a no path 612 may be followed to navigate a procedure in block 614. Navigating a procedure may include tracking and illustrating a pose of one or more instruments, the subject 30, portions of the subject 30, or the like. Navigating a procedure may be in the appropriate navigation process, as discussed above or understood by one skilled in the art.

[00120] The process 600 may then include determining whether navigation is complete in block 620. If navigation is complete, a yes block 624 may be followed to end the process 600 in block 628. Again ending the process 628 may simply end the process 600 while other procedure steps may occur relative to the subject 30, determined by the user 72, or the like.

[00121] If a detached alert is present, a yes path 640 may be followed. The yes path may include alerting the user in block 644. Alerting the user may occur in any appropriate manner, such as discussed above. In various embodiments, navigation may be stopped in block 648. However, an illustration of a current or last pose before the alert may be displayed for the user for various purposes. A complete or full navigation may be selected to be completed or continued and therefore a determination of whether navigation is complete in block 620 may occur after stopping navigation block 648. Again, if navigation is complete the yes path 624 may be followed. If navigation is not completed, a no path 654 may be followed to a determination of whether the detachment alert is present in block 608.

[00122] After determining navigation is not complete in block 620 the user 72 may reset the navigation system, check the status of all of the selected tracking devices, or the like to clear the alert. Therefore the user may perform various steps in addition to or separate to the process 600 to assist in removing the alert. The process 600, however, may be used by the user 72 when using the navigation system 26 to provide an alert to the user 72 if one or more tracking devices is possibly attached or an alert is present due to a sense attachment, at least as discussed above.

[00123] Thus, the navigation system 26 may be used to perform a procedure or as a system for performing a procedure on the subject 30. One or more tracking devices may be positioned and tracked with the tracking systems to allow navigation with the navigation system 26. A plurality of the tracking devices on various portions of the subject 30 also allow for a determination or an alert that a detachment has occurred for one or more of the tracking devices.

[00124] Examples

[00125] Example 1 - A system for alerting a user regarding a status of a tracking device, comprising: a tracking device associated with a subject member; a navigation system configured to determine a pose of the tracking device; an alert system configured to alert the user to a status of the tracking device; wherein the alert system comprises an output device to provide an alert to the user.

[00126] Example 2 - The system of Example 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible pose of at least one member associated with at least one of the first tracking device or the second tracking device.

[00127] Example s- The system of Example 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible anatomical pose of at least the subject member.

[00128] Example 4 - The system of Example 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a derivative of a motion of a tracking device compared to a predetermined plausible at least one of a velocity, acceleration, or force.

[00129] Example 5 - The system of Example 1 , further comprising: an instrument; and an instrument tracking device; wherein the navigation system includes a processor module configured to execute instructions to track the instrument relative to the subject member and determine a plausible pose of the subject member.

[00130] Example 6 - The system of Example 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of the tracking device compared to previous poses of the tracking device and motions related to a connection component of the tracking device.

[00131] Example 7 - The system of Example 1 , further comprising: a camera system configured to image the subject member; wherein the navigation system includes a processor module configured to execute instructions to compare a determined tracked pose of the subject member and the image of the subject member.

[00132] Example 8 - The system of Example 1 , wherein the tracking device further comprises: a sensor configured to generate a force or torque signal based on a sensed force or torque at the sensor; wherein the force or torque signal from the sensor is operable to be compared to a predetermined characteristic of detachment.

[00133] Example 9 - The system of Example 1 , further comprising: a sensor configured to generate a linear acceleration or angular velocity signal based on a sensed motion at the subject member; wherein the linear acceleration or angular velocity signal from the sensor is operable to be compared to a determined pose of the tracking device.

[00134] Example 10 - The system of Example 1 , further comprising: a switch configured to have a first configuration between the tracking device and the subject member and a second configuration between the tracking device and the subject member.

[00135] Example 11 - The system of Example 10, wherein a difference between the first configuration and the second configuration is a resistance determination.

[00136] Example 12 - The system of Example 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of a first tracking device relative to a previous pose of the first tracking device to determine a possible detachment of the tracking device from the subject member based on a machine learned model.

[00137] Example 13 - A method of determining a probable detachment of a tracking device from a subject member, comprising: tracking the tracking device; and evaluating at least one of a current pose or change in pose of the subject member to determine the probability of the detachment of the tracking device from the subject member.

[00138] Example 14 - The method of Example 13, further comprising at least one of: (1 ) evaluating a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible pose of at least one member associated with at least one of the first tracking device or the second tracking device, (2) evaluating a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible anatomical pose of at least the subject member, (3) evaluating a derivative of a motion of a tracking device compared to a predetermined plausible at least one of a velocity, acceleration, or force, or (4) evaluating a current pose of the tracking device compared to previous poses of the tracking device and motions related to a connection component of the tracking device.

[00139] Example 15 - The method of Example 13, further comprising: tracking an instrument; and determining if the tracked pose of the instrument creates a tracked pose of the subject member.

[00140] Example 16 - The method of Example 13, further comprising: acquiring an image of the subject member with a camera system; and comparing a determined tracked pose of the subject member and the image of the subject member.

[00141] Example 17 - The method of Example 13, further comprising: providing the tracking device with a force sensor; generating a force signal based on a sensed force at the force sensor; and comparing the force signal from the force sensor to a determined pose of the tracking device.

[00142] Example 18 - The method of Example 13, further comprising: providing a sensor at the subject member; generating a linear acceleration or angular velocity signal based on a sensed condition by the provided sensor; comparing a determined pose of the tracking device with the linear acceleration or angular velocity signal from the sensor.

[00143] Example 19 -The method of Example 13, further comprising: providing a switch configured to have a first configuration between the tracking device and the subject member and a second configuration between the tracking device and the subject member.

[00144] Example 20 -The method of Example 13, further comprising evaluating a current pose of a first tracking device relative to a previous pose of the first tracking device to determine a possible detachment of the tracking device from the subject member based on a machine learned model.

[00145] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[00146] Instructions may be executed by a processor and may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.

[00147] The apparatuses and methods described in this application may be partially or fully implemented by a processor (also referred to as a processor module) that may include a special purpose computer (i.e. , created by configuring a processor) and/or a general purpose computer to execute one or more particular functions embodied in computer programs. The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may include a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services and applications, etc.

[00148] The computer programs may include: (i) assembly code; (ii) object code generated from source code by a compiler; (iii) source code for execution by an interpreter; (iv) source code for compilation and execution by a just-in-time compiler, (v) descriptive text for parsing, such as HTML (hypertext markup language) or XML (extensible markup language), etc. As examples only, source code may be written in C, C++, C#, Objective-C, Haskell, Go, SQL, Lisp, Java®, ASP, Perl, Javascript®, HTML5, Ada, ASP (active server pages), Perl, Scala, Erlang, Ruby, Flash®, Visual Basic®, Lua, or Python®.

[00149] Communications may include wireless communications described in the present disclosure can be conducted in full or partial compliance with IEEE standard 802.11 -2012, IEEE standard 802.16-2009, and/or IEEE standard 802.20- 2008. In various implementations, IEEE 802.11 -2012 may be supplemented by draft IEEE standard 802.11ac, draft IEEE standard 802.11 ad, and/or draft IEEE standard 802.11 ah.

[00150] A processor, processor module, module or ‘controller’ may be used interchangeably herein (unless specifically noted otherwise) and each may be replaced with the term ‘circuit.’ Any of these terms may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on- chip.

[00151] Instructions may be executed by one or more processors or processor modules, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” or “processor module” as used herein may refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[00152] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.

Claims

CLAIMS What is claimed is:

1. A system for alerting a user regarding a status of a tracking device, comprising: a tracking device associated with a subject member; a navigation system configured to determine a pose of the tracking device; an alert system configured to alert the user to a status of the tracking device; wherein the alert system comprises an output device to provide an alert to the user.

2. The system of Claim 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible pose of at least one member associated with at least one of the first tracking device or the second tracking device.

3. The system of Claim 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible anatomical pose of at least the subject member.

4. The system of Claim 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a derivative of a motion of a tracking device compared to a predetermined plausible at least one of a velocity, acceleration, or force.

5. The system of Claim 1 , further comprising: an instrument; and an instrument tracking device; wherein the navigation system includes a processor module configured to execute instructions to track the instrument relative to the subject member and determine a plausible pose of the subject member.

6. The system of Claim 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of the tracking device compared to previous poses of the tracking device and motions related to a connection component of the tracking device.

7. The system of Claim 1 , further comprising: a camera system configured to image the subject member; wherein the navigation system includes a processor module configured to execute instructions to compare a determined tracked pose of the subject member and the image of the subject member.

8. The system of Claim 1 , wherein the tracking device further comprises: a sensor configured to generate a force or torque signal based on a sensed force or torque at the sensor; wherein the force or torque signal from the sensor is operable to be compared to a predetermined characteristic of detachment.

9. The system of Claim 1 , further comprising: a sensor configured to generate a linear acceleration or angular velocity signal based on a sensed motion at the subject member; wherein the linear acceleration or angular velocity signal from the sensor is operable to be compared to a determined pose of the tracking device.

10. The system of Claim 1 , further comprising: a switch configured to have a first configuration between the tracking device and the subject member and a second configuration between the tracking device and the subject member.

11 . The system of Claim 10, wherein a difference between the first configuration and the second configuration is a resistance determination.

12. The system of Claim 1 , wherein the navigation system includes a processor module configured to execute instructions to: evaluate a current pose of a first tracking device relative to a previous pose of the first tracking device to determine a possible detachment of the tracking device from the subject member based on a machine learned model.

13. A method of determining a probable detachment of a tracking device from a subject member, comprising: tracking the tracking device; and evaluating at least one of a current pose or change in pose of the subject member to determine the probability of the detachment of the tracking device from the subject member.

14. The method of Claim 13, further comprising to at least one of:

(1 ) evaluating a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible pose of at least one member associated with at least one of the first tracking device or the second tracking device,

(2) evaluating a current pose of a first tracking device relative to a second tracking device compared to a predetermined plausible anatomical pose of at least the subject member,

(3) evaluating a derivative of a motion of a tracking device compared to a predetermined plausible at least one of a velocity, acceleration, or force,

(4) evaluating a current pose of the tracking device compared to predetermined plausible poses of the subject member and poses related to a connection of the tracking device to the subject member, or

(5) evaluating a current pose of the tracking device compared to previous poses of the tracking device and motions related to a connection component of the tracking device.

15. The method of Claim 13, further comprising at least one of:

(1 ) tracking an instrument and determining if the tracked pose of the instrument creates a tracked pose of the subject member,

(2) acquiring an image of the subject member with a camera system and comparing a determined tracked pose of the subject member and the image of the subject member,

(3) providing a sensor configured to generate a force or torque signal based on a sensed force or torque at the sensor to be compared to a predetermined characteristic of detachment,

(4) providing a sensor configured to generate a linear acceleration or angular velocity signal based on a sensed motion at the subject member to be compared to a determined pose of the tracking device, or

(5) providing a switch configured to have a first configuration between the tracking device and the subject member and a second configuration between the tracking device and the subject member.