Computer-assisted pelvic surgery navigation

Abstract

To provide surgical navigation systems for pelvic surgery.SOLUTION: A system for computer-assisted navigation during surgery includes a computer platform that operates to identify a set of locations at which a navigated instrument is palpitating a landmark defined on a surface of a pelvic bone of a patient. Further operations determine a center of rotation for a pelvic acetabulum of the patient based on the identified set of locations at which the navigated instrument is palpitating the landmark. Operations determine an orientation of an anterior pelvic plane (APP) and / or a functional pelvic plane (FPP) of the patient based on the identified set of locations at which the navigated instrument is palpitating the landmark and based on the determined center of rotation for the pelvic acetabulum.SELECTED DRAWING: Figure 13C

Description

[Technical Field]

[0001] The present disclosure relates to medical devices and systems, and more particularly to surgical navigation systems for pelvic surgery. [Background technology]

[0002] Computer-aided surgical navigation systems have become a well-established technology in the operating room for providing surgeons with computerized visualization of how surgical instruments or other devices posed relative to a patient correlate to their pose relative to medical images of the patient's anatomy and how those poses correlate to preoperative surgical plans. Camera tracking systems for computer-aided surgical navigation typically use a set of tracking cameras to track the pose of a reference element on a surgical instrument, which is positioned by the surgeon during surgery, relative to a patient reference element (also known as a "dynamic reference base" (DRB)) fixed to the patient. A computer model of the actual instrument is associated with the reference element so that the computer model can be overlaid on a registered image of the patient's anatomy. The camera tracking system uses the relative pose of the reference element to determine how the actual instrument poses relative to the patient and how the computer model of the actual instrument correspondingly poses as an overlay on the medical image. This allows surgeons to use real-time visual feedback of the relative pose to navigate surgical instruments during a patient's surgical procedure.

[0003] A robotic system for knee replacement can be used that has a serial arm to which a passive structure that guides the saw blade is attached. For example, a sagittal saw can be attached to the end of the passive structure to guide the cutting plane. The system can allow the surgeon to hold the sagittal saw and cut bone while viewing various types of relevant feedback and information associated with the defined plan and / or progress of the surgical procedure on a navigation system (e.g., a standalone display or an augmented reality (AR) headset).

[0004] The serial arm can be moved to the desired surgical position through computer-guided control according to the surgeon's requirements, which can be provided, for example, via a foot pedal, touchscreen, AR interaction, etc. Passive structures allow the surgeon to precisely remove bone in the cutting plane. The progress of bone removal can be measured through camera tracking of fiducials on the bone and on reference elements attached to the sagittal saw.

[0005] Various workflows may be available for use with the system. Some workflows require a preoperative scan or image of the patient (e.g., X-ray, Computerized Tomography (CT)), while image-less workflows do not require preoperative images. To obtain intraoperative information about the patient's anatomy, the surgeon measures key bone parameters using a camera tracking system and appropriate tracked instruments to capture points on the patient's anatomy. This information is later used to plan the position and orientation of the implant relative to the patient's anatomy and to navigate the robot and surgical instruments during the surgical procedure.

[0006] Some workflows involve having the surgeon rigidly attach reference elements to one or more bones, which include fiducials detected by a tracking camera for computer-assisted navigation. The reference elements allow the navigation system to track the position of the bones. The reference elements can be positioned on the bones in the following ways: attached to the bones (e.g., the pelvis or femur and tibia, depending on the surgical procedure being performed) using fixation structures (e.g., screw pins, "crocodile" jaws) and oriented so that they can be seen by the tracking camera of the navigation system. The position and orientation of the reference elements must remain rigidly fixed relative to the bones.

[0007] Another step in the various workflows is to register the patient in the tracking space of the navigation system. Patient registration can involve matching the patient's anatomy with corresponding numerical representations of bones, usually 3D models of bones. The bone representations can either be constructed from a set of CT images (CT workflow) or based on generic bone models (image-less workflow).

[0008] Current surgical procedures provide advanced computer-assisted navigation once the patient's bony landmarks are properly aligned for tracking, but the current procedures for alignment should be improved to become more automated and provide more accurate assisted navigation during surgery. Summary of the Invention

[0009] Some embodiments of the present disclosure are directed to a system for computer-assisted navigation during surgery. The system includes a computer platform operative to identify a set of locations where a navigated instrument is in contact with landmarks defined on the surface of a patient's pelvis, femur, or both. A further operation determines a center of rotation for the patient's pelvis acetabulum based on the identified set of locations where the navigated instrument is in contact with the landmarks. The operation determines an orientation of the patient's anterior pelvic plane (APP) and / or functional pelvic plane (FPP) based on the identified set of locations where the navigated instrument is in contact with the landmarks and based on the determined center of rotation for the pelvis acetabulum.

[0010] Some other corresponding embodiments of the present disclosure are directed to a computer program product comprising a non-transitory computer-readable medium storing instructions executable by at least one processor to perform operations for computer-assisted navigation during a surgical procedure. The operations identify a set of locations where a navigated instrument is palpating landmarks defined on a surface of a patient's pelvic bone. A further operation determines a center of rotation for the patient's pelvis acetabulum based on the identified set of locations where the navigated instrument is palpating the landmarks. The operations determine an orientation of the patient's anterior pelvic plane (APP) and / or functional pelvic plane (FPP) based on the identified set of locations where the navigated instrument is palpating the landmarks and based on the determined center of rotation for the pelvis acetabulum.

[0011] Other systems, computer program products, and related methods for computer-assisted navigation during surgery according to embodiments of the present subject matter will be, or will become, apparent to one of ordinary skill in the art upon review of the following figures and detailed description. All such additional systems, computer program products, and methods are intended to be included within this specification, be within the scope of the present subject matter, and be protected by the accompanying claims. Furthermore, it is intended that all embodiments disclosed herein may be implemented separately or combined in any manner and / or combination. [Brief explanation of the drawings]

[0012] Aspects of the present disclosure are illustrated by way of example and not limitation in the accompanying drawings, in which: [Figure 1] FIG. 1 is an overhead view of a surgical system positioned during a surgical procedure in a surgical operating room, including a camera tracking system for computer-assisted navigation during surgery, and which may further include a surgical robot for robotic assistance, according to some embodiments. [Figure 2] 1 illustrates a camera tracking system and a surgical robot positioned relative to a patient, according to some embodiments. [Figure 3] 10A-10C further illustrate a camera tracking system and a surgical robot configured in accordance with some embodiments. [Figure 4] 1 illustrates a block diagram of a surgical system including an augmented reality headset, a computer platform, an imaging device, and a surgical robot configured to operate in accordance with some embodiments. [Figure 5] 1 illustrates a ball-tip stylus constructed in accordance with some embodiments of the present disclosure. [Figure 6] 10 illustrates a user interface displayed to guide a user through tactile alignment of condylar surfaces using a ball-tip stylus, according to some embodiments of the present disclosure. [Figure 7] 10 illustrates a schematic diagram of operations for defining an acquired bone surface, offset along a local normal vector based on the radius of the ball, and then translating toward the bone surface, in accordance with some embodiments of the present disclosure. [Figure 8] 1 illustrates a flowchart of an image-less workflow during the intraoperative portion of a total hip arthroplasty (THA) surgery, according to some embodiments of the present disclosure. [Figure 9] 1 illustrates a flowchart of a pre-registration patient preparation process according to some embodiments of the present disclosure. [Figure 10A] 10 illustrates radiographic tilt angles measured in the coronal plane of a patient, according to some embodiments of the present disclosure. [Figure 10B] 1 illustrates a radiographic version angle measured relative to a patient's coronal plane, according to some embodiments of the present disclosure. [Figure 11] 10A-10C illustrate different views of landmarks and axes for alignment of a patient's functional pelvic plane (FPP) and anterior pelvic plane (APP), according to some embodiments of the present disclosure. [Figure 12] 10 illustrates a flowchart for alignment of a patient's APP and FPP, according to some embodiments of the present disclosure. [Figure 13A] 10 illustrates an example of APP and / or FPP registration using a tracking marker plane of a navigated instrument, according to some embodiments of the present disclosure. [Figure 13B] 10 illustrates an example of APP and / or FPP registration using a tracking marker plane of a navigated instrument, according to some embodiments of the present disclosure. [Figure 13C] 10 illustrates an example of APP and / or FPP registration using a tracking marker plane of a navigated instrument, according to some embodiments of the present disclosure. [Figure 14]10 illustrates an example of aligning an APP and / or FPP using the axes of a navigated instrument and a tracking camera including an inertial measurement unit (IMU), according to some embodiments of the present disclosure. [Figure 15] 10 illustrates a flowchart of operations for measuring a patient's leg length and offset, according to some embodiments of the present disclosure. [Figure 16] 10 illustrates a flowchart for aligning a patient's pelvis and acetabulum, according to some embodiments of the present disclosure. [Figure 17] 10 illustrates painting the acetabular fossa with a navigated instrument according to some embodiments of the present disclosure. [Figure 18] 1 illustrates a user interface for a planning view that displays a graphical representation of a typical bone with extracted (e.g., aligned) landmarks (shown as bright dots) and a graphical representation of which surfaces have been acquired through tactile actions. [Figure 19] 1 illustrates a flowchart of operations that may be performed by a computer platform of a system for computer-assisted navigation during surgery, according to some embodiments of the present disclosure. [Figure 20] 10 illustrates a flowchart of additional or alternative operations performed by a computer platform of a system for computer-assisted navigation during a surgical procedure on a patient, according to some embodiments of the present disclosure. [Figure 21] 10 illustrates a schematic diagram of operations for obtaining femur and / or tibia features according to some embodiments of the present disclosure. [Figure 22] 10 illustrates a schematic diagram of structures and operations that may be used in a second operating approach to acquire features of the femur and / or tibia. DETAILED DESCRIPTION OF THE INVENTION

[0013] It is understood that the present disclosure is not limited in its application to the details of construction and arrangements of components set forth in the description herein or illustrated in the drawings. The teachings of the present disclosure may be used and implemented in other embodiments and may be practiced or carried out in various ways. It is also understood that the phraseology and terminology used herein are for purposes of description and should not be regarded as limiting. The use of "including," "comprising," or "having," and variations thereof, herein is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items. Unless otherwise specified or limited, the terms "mounted," "connected," "attached," "supported," and "coupled," and variations thereof, are used broadly and encompass both direct and indirect mounting, connecting, attaching, supporting, and coupling. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings.

[0014] The following discussion is presented to enable those skilled in the art to make and use embodiments of the present disclosure. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the principles herein may be applied to other embodiments and applications without departing from the embodiments of the present disclosure. Thus, the embodiments are not intended to be limited to the embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description should be read with reference to the drawings, in which like elements in different drawings have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the embodiments. Those skilled in the art will recognize that the examples provided herein have many useful alternatives and are within the scope of the embodiments.

[0015] A first set of embodiments of the present disclosure is directed to a system for computer-assisted navigation during surgery that operates with a navigated ball-tip stylus used to contact the surface of a bone as the stylus moves across the bone. For example, the bone can be continuously contacted by a process known as “surface painting,” which refers to a user touching, e.g., tapping, a ball at individual surface locations on the bone, preferably in a zigzag fashion, while maintaining contact with the bone surface while the stylus is tracked to enable definition of the bone surface obtained according to various embodiments disclosed herein. The bone can also be continuously contacted by tactile contact, i.e., by repeatedly lifting and contacting individual surface locations while a navigated ball-tip stylus moves over the bone, preferably in a zigzag fashion. For purposes of this application, the phrases “painting,” “surface painting,” and tactile contact are used interchangeably to refer to contact by either continuous or intermittent contact of the bone. Before describing these embodiments in detail, various components of systems that may be used in conjunction with and / or to implement the embodiments will be described with reference to FIGS. 1-4.

[0016] A second set of embodiments of the present disclosure, which may be used in addition to, in conjunction with, or as an alternative to the first set of embodiments, is directed to a system for computer-assisted navigation during surgery, including a computer platform operable to identify a set of locations where a navigated instrument is palpating landmarks defined on a surface of a patient's pelvic bone. The computer platform is further operable to determine a center of rotation for the pelvis acetabulum based on the identified set of locations where the navigated instrument is palpating landmarks, and to determine an orientation of an anterior pelvic plane (APP) and / or a functional pelvic plane (FPP) based on the identified set of locations where the navigated instrument is palpating landmarks and based on the determined center of rotation for the pelvis acetabulum.

[0017] A first set of embodiments is discussed below.

[0018] Figure 1 is an overhead view of a surgical system deployed during a surgical procedure in a surgical operating room. The system includes a camera tracking system 200 for computer-assisted navigation during surgery and may further include a surgical robot 100 for robotic assistance, according to some embodiments. Figure 2 illustrates the camera tracking system 200 and surgical robot 100 positioned relative to a patient, according to some embodiments. Figure 3 further illustrates the camera tracking system 200 and surgical robot 100 configured in accordance with some embodiments. Figure 4 illustrates a block diagram of a surgical system including an extended reality (XR) headset 150, a computer platform 400, an imaging device 420, and the surgical robot 100 configured to operate in accordance with some embodiments.

[0019] The XR headset 150 may be configured to augment a real-world scene with computer-generated XR images while worn by personnel in an operating room. The XR headset 150 may be configured to provide an augmented reality (AR) viewing environment by displaying the computer-generated XR images on a see-through display screen that allows light from the real-world scene to pass through for combined viewing by the user. Alternatively, the XR headset 150 may be configured to provide a virtual reality (VR) viewing environment by preventing or substantially preventing light from the real-world scene from being viewed directly by the user while the user is viewing the computer-generated AR images on the display screen. The XR headset 150 may be configured to provide both AR and VR viewing environments. Accordingly, the term XR headset may be referred to as an AR headset or a VR headset.

[0020] 1-4, a surgical robot 100 may include, for example, one or more robotic arms 104, a display 110, an end effector 112 including, for example, a guide tube 114, and an end effector reference element that may include one or more tracking reference points. A patient reference element 116 (DRB) has multiple tracking reference points and is fixed directly to a patient 210 (e.g., to a patient bone such as the pelvis, femur, or tibia). A reference element 170 is attached to or formed on an instrument, surgical tool, surgical implant device, or the like.

[0021] Camera tracking system 200 includes tracking cameras 204, which may be spaced apart stereo cameras configured to have overlapping fields of view. Camera tracking system 200 may have any suitable configuration of arms 202 for moving, orienting, and supporting tracking cameras 204 at desired locations, and may include at least one processor operable to track the locations of individual fiducials and the pose of an array of fiducials of a reference element.

[0022] As used herein, the term "attitude" refers to the location (e.g., along three orthogonal axes) and / or rotation angle (e.g., about three orthogonal axes) of a reference point (e.g., a DRB) relative to another reference point (e.g., a surveillance reference point) and / or a defined coordinate system (e.g., a camera coordinate system, a navigation coordinate system, etc.). Thus, an attitude may be defined based solely on the multidimensional location of a reference point relative to another reference point and / or a defined coordinate system, based solely on the multidimensional rotation angle of a reference point relative to other reference points and / or a defined coordinate system, or based on a combination of the multidimensional location and the multidimensional rotation angle. Thus, the term "attitude" is used to refer to a location, a rotation angle, or a combination thereof.

[0023] The tracking camera 204 may include an infrared camera (e.g., a bifocal or stereo photogrammetry camera) operable to identify a single reference point (e.g., a monitoring reference point) and active and passive tracking reference points relative to a reference element, which may be formed on or attached to, for example, the patient 210 (e.g., a patient reference element, DRB, etc.), the end effector 112 (e.g., an end effector reference element), an XR headset 150 worn by the surgeon 120 and / or surgical assistant 126, etc., in a given measurement volume of a camera coordinate system while being visible from the viewpoint of the tracking camera 204. The tracking camera 204 may scan the given measurement volume and detect light emitted from or reflected from the reference points to identify and determine the location of the individual reference points and the pose of the reference elements in three dimensions. For example, an active reference element may include an infrared-emitting reference point that is activated by an electrical signal (e.g., an infrared light emitting diode (LED)), and a passive reference element may include a retro-reflective reference point that reflects infrared light emitted by an illuminator on, for example, the tracking camera 204 or other suitable device (e.g., reflects incident IR radiation in the direction of the incident light).

[0024] XR headset 150 may each include tracking cameras (e.g., spaced stereo cameras) that can track the locations of surveillance reference points and the poses of reference elements, respectively, within the XR camera headset's field-of-view (FOV) 152 and 154. Thus, as illustrated in FIG. 1 , the locations of surveillance reference points and the poses of reference elements on various objects can be tracked while within the FOVs 152 and 154 of XR headset 150 and / or the FOV 600 of tracking camera 204.

[0025] 1 and 2 illustrate potential configurations for placement of a camera tracking system 200 and surgical robot 100 within an operating room environment. Computer-assisted navigated surgery can be provided by the camera tracking system controlling an XR headset 150 for displaying surgical navigation information and / or other displays 34, 36, and 110. The surgical robot 100 is optional during computer-assisted navigated surgery.

[0026] The camera tracking system 200 may operate using tracking information and other information provided by multiple XR headsets 150, such as inertial and optical tracking information (frames of tracking data). The XR headsets 150 may operate to display visual information and play audio information to the wearer. This information may come from local sources (e.g., the surgical robot 100 and / or other medical equipment), imaging devices 420 ( FIG. 4 ), and remote sources (e.g., a patient medical image server), and / or other electronic devices. The camera tracking system 200 may track reference points with six degrees of freedom (6 DOF) relative to three axes of a 3D coordinate system and angles of rotation about each axis. The XR headsets 150 may also operate to track hand postures and gestures to enable gesture-based interaction with “virtual” buttons and interfaces displayed through the XR headsets 150, and may interpret hand or finger pointing or gestures as various defined commands. Additionally, XR headsets 150 may have a digital color camera sensor with 1-10x magnification, called a digital magnifier. In some embodiments, one or more of XR headsets 150 are minimalist XR headsets that display local or remote information but contain fewer sensors and are therefore lighter in weight.

[0027] An "outside-in" machine vision navigation bar supports tracking cameras 204 and may include a color camera. Machine vision navigation bars generally do not move as frequently or quickly as the XR headset 150 while positioned on the wearer's head, and therefore have a more stable view of the environment. The patient reference element 116 (DRB) is generally rigidly attached to the patient with a stable pitch and roll relative to gravity. This local, precise patient reference 116 can serve as a common reference frame of reference for other tracked elements, such as the reference element on the end effector 112, the instrument reference element 170, and the reference element on the XR headset 150.

[0028] In some embodiments, at the end of the end effector, instruments are connected to perform operations such as cutting, reaming, broaching, drilling, and screw placement.

[0029] When present, the surgical robot (also referred to as "robot") may be positioned near or next to the patient 210. The robot 100 may be positioned in any suitable location near the patient 210, depending on the area of the patient 210 that will undergo the surgical procedure. The camera tracking system 200 may be separate from the robotic system 100 and may be positioned at the feet of the patient 210. This location allows the tracking camera 200 to have a direct line of sight to the surgical area 208. In the configuration shown, the surgeon 120 may be positioned opposite the robot 100 but still be able to operate the end effector 112 and display 110. The surgical assistant 126 may also be positioned opposite the surgeon 120, with access to both the end effector 112 and the display 110. If desired, the locations of the surgeon 120 and assistant 126 may be reversed. The anesthesiologist 122, nurse, or scrub technician can operate equipment that may be connected to display information from the camera tracking system 200 on the display 34.

[0030] As with other components of the robot 100, the display 110 may be mounted on the surgical robot 100 or at a remote location. The end effector 112 may be coupled to the robotic arm 104 and controlled by at least one motor. In some embodiments, the end effector 112 includes a guide tube 114 configured to receive and orient a surgical instrument, tool, or implant used to perform a surgical procedure on the patient 210. In some other embodiments, the end effector 112 includes a passive structure that guides a saw blade (e.g., a sagittal saw) along a defined cutting plate.

[0031] As used herein, the term “end effector” is used interchangeably with the terms “end effector” and “effector element.” The term “instrument” is used non-limitingly and interchangeably with “tool” and “implant” and can generally refer to any type of device that can be used during a surgical procedure according to embodiments disclosed herein. The more general term device can also refer to structures such as end effectors. Exemplary instruments, tools, and implants include, but are not limited to, drills, screwdrivers, saws, dilators, retractors, probes, implant inserters, and implant devices such as screws, spacers, interbody fusion devices, plates, rods, and the like. While generally shown with a guide tube 114, it will be understood that the end effector 112 can be substituted with any suitable instrument suitable for use in a surgical procedure. In some embodiments, the end effector 112 can comprise any known structure for effecting movement of a surgical instrument in a desired manner.

[0032] The surgical robot 100 is operable to control the translation and orientation of the end effector 112. The robot 100 may move the end effector 112 under computer control, for example, along the x-, y-, and z-axes. The end effector 112 may be configured to selectively rotate about one or more of the x-, y-, and z-axes and the Z-frame axis, such that one or more of the Euler angles (e.g., roll, pitch, and / or yaw) associated with the end effector 112 may be selectively computer controlled. In some embodiments, selective control of the translation and orientation of the end effector 112 may enable the performance of medical procedures with significantly improved accuracy, as compared to, for example, conventional robots utilizing 6DOF robotic arms that include only rotational axes. For example, the surgical robot 100 may be used to operate on a patient 210, with the robotic arm 104 positioned above the body of the patient 210 and the end effector 112 selectively angled relative to the z-axis toward the body of the patient 210.

[0033] In some exemplary embodiments, the XR headset 150 can be controlled to dynamically display an updated graphical representation of the surgical instrument pose, so that the user is always aware of the surgical instrument pose during the procedure.

[0034] In some further embodiments, the surgical robot 100 may be operable to correct the path of the surgical instrument guided by the robotic arm 104 if the surgical instrument deviates from a selected pre-planned trajectory. The surgical robot 100 may be operable to allow stopping, modifying, and / or manual control of the movement of the end effector 112 and / or surgical instrument. Thus, in use, a surgeon or other user may use the surgical robot 100 as part of a computer-assisted navigated procedure and have the option to stop, modify, or manually control the autonomous or semi-autonomous movement of the end effector 112 and / or surgical instrument.

[0035] Reference element fiducials can be formed on or connected to the robotic arms 102 and / or 104, the end effector 112 (e.g., end effector element 114 of FIG. 2 ), and / or the surgical instrument (e.g., instrument element 170) to enable pose tracking in a defined coordinate system, such as, for example, 6 DOF along three orthogonal axes and rotation about an axis. The reference elements enable each of the marked objects (e.g., end effector 112, patient 210, and surgical instrument) to be tracked by the tracking camera 200, and the tracked poses can be used to provide navigated guidance during a surgical procedure and / or to control the movement of the surgical robot 100 to guide the end effector 112 and / or the instrument manipulated by the end effector 112.

[0036] 3, surgical robot 100 may include a display 110, upper arm 102, lower arm 104, end effector 112, vertical column 312, casters 314, table 318, and ring 324 that uses light to indicate status and other information. Cabinet 106 may house electrical components of surgical robot 100, including, but not limited to, a battery, a power distribution module, a platform interface board module, and a computer. Camera tracking system 200 may include display 36, tracking camera 204, arm 202, a computer housed in cabinet 330, and other components.

[0037] In computer-assisted navigated surgery, vertical 2D scan slices, such as axial, sagittal, and / or coronal views, of a patient's anatomy are displayed to allow a user to visualize the patient's anatomy along with the relative pose of surgical instruments. An XR headset or other display can be controlled to display one or more 2D scan slices of the patient's anatomy along with a 3D graphical model of the anatomy. The 3D graphical model can be generated from a 3D scan of the patient, for example, by a CT scanning device, and / or can be generated based on a baseline model of the anatomy that is not necessarily formed from a patient scan.

[0038] Exemplary surgical systems: FIG. 4 illustrates a block diagram of a surgical system including an XR headset 150, a computer platform 400, an imaging device 420, and a surgical robot 100 configured to operate in accordance with some embodiments.

[0039] The imaging device 420 may include a C-arm imaging device, an O-arm imaging device, other imaging devices, and / or a patient image database (2D and / or 3D images). The XR headset 150 provides an improved human interface for performing navigated surgical procedures. The XR headset 150 may be configured to provide functionality, for example, via the computer platform 400, including, but not limited to, any one or more of the following: hand gesture-based command recognition, display of XR graphical objects on the display device 438 of the XR headset 150 and / or another display device. The display device 438 may include a video projector, a flat panel display, etc. The user may view the XR graphical objects as overlays anchored to specific real-world objects viewed through the see-through display screen. The XR headset 150 may additionally or alternatively be configured to display video streams from one or more cameras mounted on the XR headset 150 and other cameras on the display device 438.

[0040] The electrical components of the XR headset 150 may include multiple cameras 430, a microphone 432, a gesture sensor 434, a posture sensor (e.g., an inertial measurement unit (IMU)) 436, a display device 438, and a wireless / wired communication interface 440. The camera 430 of the XR headset 150 may be a visible light capture camera, a near-infrared capture camera, or a combination of both.

[0041] The camera 430 may be configured to operate as a gesture sensor 434 by tracking hand gestures of an identified user performed within the field of view of the camera 430. Alternatively, the gesture sensor 434 may be a proximity sensor and / or a touch sensor that senses hand gestures performed in proximity to the gesture sensor 434 and / or senses physical contact, e.g., a tap on the sensor 434 or its housing. The attitude sensor 436, e.g., an IMU, may include a multi-axis accelerometer, a tilt sensor, and / or another sensor capable of sensing rotation and / or acceleration of the XR headset 150 along one or more defined coordinate axes. Some or all of these electrical components may be housed in the head-worn component housing or in a separate housing configured to be worn elsewhere, such as on the waist or shoulder.

[0042] As described above, the surgical system includes a camera tracking system 200 that may be connected to a computer platform 400 for motion processing and that may include a navigation controller 404 and / or provide other motion functions of an XR headset controller 410. The surgical system may include a surgical robot 100. The navigation controller 404 may be configured to provide visual navigation guidance to the operator for moving and positioning the surgical tool relative to the patient's anatomy, for example, based on a surgical plan from a surgical planning function that defines where a surgical procedure will be performed on the anatomy using the surgical tool, and based on the pose of the anatomy determined by the camera tracking system 200. The navigation controller 404 may be further configured to generate navigation information based on a target pose for the surgical tool, the pose of the anatomy, and the pose of the surgical tool and / or the end effector of the surgical robot 100. The navigation information may be displayed through the display device 438 of the XR headset 150 and / or another display device to indicate where the surgical tools and / or end effectors of the surgical robot 100 should be moved to perform the surgical procedure according to the defined surgical plan.

[0043] The electrical components of the XR headset 150 may be operatively connected to the electrical components of the computer platform 400 through a wired / wireless interface 440. The electrical components of the XR headset 150 may be operatively connected to various imaging devices 420, such as a C-arm imaging device, an O-arm imaging device, other imaging devices, patient image databases, and / or other medical equipment through the wired / wireless interface 440, for example, through the computer platform 400 or may be directly connected.

[0044] The surgical system may include an XR headset controller 410 that resides at least partially within the XR headset 150, the computer platform 400, and / or another system component connected via a wired cable and / or wireless communication link. Various functions are provided by software executed by the XR headset controller 410. The XR headset controller 410 is configured to receive information from the camera tracking system 200 and the navigation controller 404 and to generate XR images based on the information for display on the display device 438.

[0045] The XR headset controller 410 can be configured to operatively process frames of tracking data from the tracking camera 430 (tracking camera), signals from the microphone 1620, and / or information from the orientation sensor 436 and gesture sensor 434 to generate information for display as an XR image on the display device 438 and / or for display on another display device for viewing by a user. Thus, the XR headset controller 410, illustrated as a circuit block within the XR headset 150, should be understood as being operatively connected to the other illustrated components of the XR headset 150, but not necessarily within a common housing or otherwise transportable by a user. For example, the XR headset controller 410 can reside within the computer platform 400, which in turn can reside within the cabinet 330 of the camera tracking system 200, the cabinet 106 of the surgical robot 100, etc.

[0046] Acquiring bone surfaces through tactile sensation ("painting") using a ball-tip stylus: Various embodiments are directed to registering a patient's anatomy in algorithms for computer-assisted navigation during surgery by acquiring specific landmarks on the bone using a process of palpating the bone surface with a tracked ball-tip stylus. The locations of the bone landmarks can be acquired and registered with a single touch of the tracked ball-tip stylus. The bone surface can be acquired and registered by multiple individual touches of the tracked ball-tip stylus, e.g., by tapping, and / or by touching the surface and then maintaining contact with the surface while moving the ball along the surface, e.g., by "painting" the surface while being tracked. Defined landmarks (e.g., most distal and posterior points) can be extracted, and other measurements of the bone surface can be performed and registered simultaneously for computer-assisted navigation. The bone surface can be defined (reconstructed) based on a cloud of points collected by moving the ball of the tracked ball-tip stylus over the bone surface.

[0047] Figure 5 illustrates a ball-tip stylus 500 configured in accordance with some embodiments of the present disclosure. Referring to Figure 5, the ball-tip stylus 500 includes a ball 610 at its tip connected through an interconnecting member 612 to a reference element 602 having an array of fiducial points 504. The fiducial points 504 may be any shape, such as a disk, sphere, etc., may be any color, and may be passive to reflect light or active to emit light.

[0048] The tip shape can have a significant effect on how easily and accurately a user can move the tip across a bone. It has been determined that a ball (spherical) tip glides more easily and consistently over a bone surface, but the radius of the tip must be considered when defining the surface location. A larger ball radius facilitates gliding ability, but makes it more difficult to access certain areas of a patient's bone, such as the acetabular cartilage or acetabular fossa of the pelvis.

[0049] A user, e.g., a surgeon, can manipulate the ball 610 of the ball-tip stylus 500 to sweep across the surface of the bone or cartilage. In doing so, the camera tracking system 200 can measure the location of the ball 610 in a continuous motion and output a cloud of location points. Alternatively, the user can measure a sufficient number of points by touching the points one by one with the ball 610 of the ball-tip stylus 500, which is then tracked by the camera tracking system 200.

[0050] The user may be guided by displayed and / or audible instructions generated by a software application, e.g., an algorithm for computer-assisted navigation, to obtain the defined surface area of the bone. Figure 6 illustrates a user interface displayed on a display device to guide a user through tactile alignment of the condylar surface 700 using a ball-tip stylus 500, according to some embodiments of the present disclosure. It should be noted that although the condylar surface is illustrated with reference to Figure 6, a similar process can be performed and similar information can be determined / identified for a patient's pelvis.

[0051] The user interface displays indicia 702 indicating that the user should use the ball-tip stylus 500 to palpate the distal medial condyle to allow the system to define the surface of the distal medial condyle and align the surface in an algorithm for computer-assisted navigation during surgery.

[0052] The location (point) acquired by the camera tracking system 200 corresponds to the center of the ball 610 during acquisition by the user. The location can be used to define an offset acquired surface of the bone. The offset acquired surface can then be translated to correspond to the actual surface of the bone based on the radius of the ball 610. The system may use a surface matching algorithm for some of these operations.

[0053] FIG. 7 illustrates a schematic diagram of operations for defining an offset acquired surface of bone 820 and then translating it toward the surface of bone 820 along a local normal vector based on the radius of ball 610 to define an acquired surface 810 of bone 820, according to some embodiments of the present disclosure. Referring to FIG. 7 , in one illustrative embodiment, the operations include obtaining the location of center 800 of ball 610 when used to palpate the surface of bone 820. The locations of center 800 of ball 610 are then mathematically connected together to define offset acquired surface 810 of bone 820, which is offset from the actual bone surface by a distance corresponding to radius 802 of ball 610. To match offset acquired surface 810 to the actual bone surface, the operations determine a local normal vector relative to the actual bone surface for each acquired location of center 800 of ball 610. The operations then translate each acquired location of center 800 of ball 610 toward bone 820 along the normal vector by a distance corresponding to radius 802 of ball 610. These movements allow the surface to be defined in a manner that is independent of the orientation of the ball-tip stylus 500, for example when it is not perpendicular to the palpated surface. The acquired bone surface that corresponds to the actual bone surface can then be defined by mathematically connecting the translated locations together.

[0054] Landmarks relevant to the surgical procedure (e.g., the most posterior and distal condylar points for the femur, the most distal point on the plateau for the tibia, etc.) can be extracted for planning and computer-assisted navigation. Based on the acquired surfaces, a registration algorithm can then match the patient's anatomy with the 3D model of the bone and / or identify additional landmarks for use in planning and computer-assisted navigation.

[0055] These operations may be more generalized according to some embodiments. Figure 19 illustrates a flowchart of operations that may be performed by a computer platform of a system for computer-assisted navigation during surgery according to some embodiments of the present disclosure.

[0056] 19 , operations may include identifying (11000) a location of a reference point 504 of a reference element 602 on the ball-tip stylus 500 within an image acquired from a tracking camera 204 having at least a partially overlapping field of view that images the ball-tip stylus 500 with a ball 610 on the ball-tip stylus touching (contacting) a surface of a bone 820. The operations determine (11002) a location of a center 800 of the ball 610 based on the location of the reference point 504 of the reference element 602. The operations define (11004) an offset acquired surface 810 of the bone based on mathematically connecting the locations of the centers 800 of the balls 610. The operations determine (11006) a local normal vector 804 to the offset acquired surface 810 for the location of the center 800 of the ball 610. The operation translates the surface 810 of the offset acquired bone 820 along the local normal vector 804 toward the surface of the bone 820 based on the radius 802 of the ball 610 to define a surface of the acquired bone 820 that ideally corresponds accurately to the surface of the actual bone 820 (11008).

[0057] An operation 11008 of translating the offset acquired bone 820 surface 810 along the local normal vector 804 based on the radius 802 of the ball 610 toward the surface of the bone 820 to define the acquired bone 820 surface may include translating (11010) the location of the center 800 of the ball 610 toward the surface of the bone 820 along the local normal vector 804 by the radius 802 of the ball 610 to define a first set of acquired bone 820 surface locations. The operation may then mathematically connect (11012) the acquired bone 820 surface locations to define the acquired bone 820 surface.

[0058] As described in more detail below, the operations may further include registering (11014) the acquired surface of bone 820 in an algorithm for computer-assisted navigation during surgery, and / or displaying (11016) a graphical representation of the acquired surface of bone 820 in a planning view for computer-assisted navigation during surgery.

[0059] Some further embodiments are directed to operations for detecting and processing outlier locations that do not correspond to locations where the ball 610 is palpating (contacting) the bone 820. Maintaining contact with the bone surface during bone surface measurements may be difficult or unnecessary. However, without operations for detecting and processing such outlier locations, these outlier locations may lead to the acquisition of numerous irrelevant points, such as while the ball 610 is moved toward and contacting the bone 820 and / or repositioned away from the bone 820. In some embodiments, these irrelevant outlier locations are identified using operations for processing the acquired locations to prevent outlier locations that are spaced away from the bone surface from being used when defining an offset acquired bone surface or an acquired surface. Outlier locations may be identified based on comparison with other determined locations. For example, when locations are connected to form a plane or a curved path, any location that deviates from the plane or path by at least a threshold distance may be flagged as an outlier.

[0060] A corresponding operation for identifying and processing outliers may include, when defining 11004 the surface of the offset-acquired bone 820 based on mathematically connecting the locations of the centers 800 of the balls 610, identifying outlier locations of the centers 800 of the balls 610 where the balls 610 do not palpate the surface of the bone 820. The operation may then define 11004 the surface of the offset-acquired bone 820 based on mathematically connecting the locations of the centers 800 of the balls 610 without mathematically connecting the outlier locations of the centers 800 of the balls 610 where the balls 610 do not palpate the surface of the bone.

[0061] The operation of identifying an outlier location of the center 800 of the ball 610 where the ball 610 is not palpating (contacting) the surface of the bone 820 from among the locations of the center 800 of the ball 610 may include identifying an outlier location of the center 800 of the ball 610 where the ball 610 is not palpating (contacting) the surface of the bone 820 based on an outlier location of the center 800 of the ball 610 that has at least a first threshold distance in a direction along the local normal vector 804 to the offset acquired surface 810 from other locations of the center 800 of the ball 610 that are within a second threshold distance in a direction along the offset acquired surface 810.

[0062] Exemplary operations for acquiring femoral and / or tibia features and axes are now described, and these operations can similarly be performed to acquire pelvic features and axes. Figure 21 illustrates a schematic diagram of operations for acquiring femoral and / or tibia features, according to some embodiments of the present disclosure. While exemplary femoral and / or tibia features are acquired with reference to Figure 21, similar operations / steps can be performed to acquire / identify other features of the patient (e.g., pelvic features).

[0063] Referring to FIG. 21 , palpable acquisition of features and other landmarks on the anterior and distal surfaces of the femur and the tibial plateau can be performed using a ball-tip stylus 500. For example, these areas may be naturally exposed, such as the femur, or may be easily accessible, such as through hyperflexion of the joint, which provides easy access to approximately 75% of the tibial plateau. However, the posterior aspect of the condylar surface is difficult to acquire through palpation with an adequate level of ease. From a clinical perspective, acquisition of the posterior condylar aspect may be required to determine the posterior condylar axis 910, which is one option for setting the internal and / or external rotation of the femoral component during planning.

[0064] The operations disclosed herein can be used to obtain the posterior aspect of the condylar surface using Whiteside's line 920 and / or the transepicondylar axis 900.

[0065] This motion approach uses two acquisition steps: in one step, landmarks on the anterior and distal aspects of the femur are acquired and a partial alignment of the femur is performed; an acquisition of the tibial plateau and a full alignment of the tibia is performed; a tibial resection is performed; and then, in another step, an acquisition of the posterior aspects of the femoral condyles is performed.

[0066] For this operational approach, in the context of FIG. 19 , the acquired bone surfaces can define the anterior and distal surfaces of the femur that are palpated by the ball 610. A corresponding operation for one of the steps can include acquiring the location of the tibial plateau (e.g., 11000-11008 in FIG. 19 ) based on the locations of the anterior and distal surfaces of the femur defined by the acquired bone surfaces. A location of the tibia in tracking space can be registered (e.g., 11014 in FIG. 19 ) based on the acquired location of the tibial plateau. A corresponding operation for another of the steps can include, following the tibial resection, identifying the location of the fiducial point 504 of the reference element 602 on the ball-tip stylus 500 in a further image acquired from the tracking camera 204 that images the ball-tip stylus 500 with the ball 610 palpating (contacting) the posterior surface of the femoral condyle. The operation determines the location of the center of the ball 610 based on the location of the fiducial point of the reference element, and defines an offset acquired surface of the posterior surface of the femoral condyle based on mathematically connecting the locations of the centers of the balls 610. The operation determines a local normal vector to the offset acquired surface of the posterior surface of the femoral condyle for the location of the center of the ball 610, and translates the offset acquired surface of the posterior surface of the femoral condyle along the local normal vector toward the posterior surface of the femoral condyle based on the radius of the ball 610 to define an acquired surface of the posterior surface of the femoral condyle.

[0067] A second operational approach can use the aligned tibia with reference element 520 as a navigated instrument to acquire the posterior condylar axis. FIG. 22 illustrates a schematic diagram of structures and operations that can be used in the second operational approach to acquire femoral and / or tibial features. In FIG. 22, a virtual plane 1002 is illustrated as attached to the femur and determined using landmarks such as the mechanical axis and superior distal surface of the femur. Another virtual plane 1004 is illustrated as attached to the tibia and determined from landmarks such as the mechanical axis and proximal geometry. Another virtual plate 1000 extends perpendicular to the virtual plane 1002 through the tibia to intersect with the virtual plane 1004. The intersection of the virtual planes 1000 and 1004 is illustrated as occurring at location 1010, which corresponds to acquiring the posterior condylar axis using the aligned tibia.

[0068] Corresponding operations may include obtaining a location of the tibial plateau (e.g., 11000-11008 in FIG. 19 ) based on the locations of the anterior and distal surfaces of the femur defined by the obtained bone surfaces. The location of the tibia in tracking space may be aligned based on the obtained location of the tibial plateau (e.g., 11014 in FIG. 19 ). The operations identify, in images obtained from tracking camera 204 while ball 610 is palpating the femur, the location of a reference point of tibial reference element 520 attached to the tibia and the location of a reference point of femoral reference element 510 attached to the femur. The operations obtain the location of the posterior condylar axis based on the aligned location of the tibia and based on the identified locations of the reference points of tibial reference element 520 and femoral reference element 510.

[0069] The operation of obtaining the location of the posterior condylar axis based on the aligned location of the tibia and based on the identified locations of the fiducial points of the tibial reference element 520 and the femoral reference element 510 can include determining a distal femoral plane that is virtually attached to the femur and passes through the posterior surfaces of the femoral condyles. The operation can obtain the location of the tibial plateau based on the locations of the anterior and distal surfaces of the femur defined by the obtained bone surfaces and based on the identified locations of the fiducial points of the tibial reference element 520. The operation can determine the posterior condylar axis based on determining a proximal tibial plane that is virtually attached to the tibia and tracking movement of the location of the fiducial point of the tibial reference element 520 relative to the location of the fiducial point of the femoral reference element 510 as the tibia is rotated relative to the femur.

[0070] The operation of determining the posterior condylar axis based on tracking the movement of the location of the reference point of the tibial reference element 520 relative to the location of the reference point of the femoral reference element 510 as the tibia is rotated relative to the femur can include determining the posterior condylar axis based on identifying the location of intersection of the distal femoral plane and the proximal tibial plane.

[0071] The act of determining the distal femoral plane can include determining the distal femoral plane to be perpendicular to the mechanical axis of the femur, virtually attached to the femur, and passing through the posterior surfaces of the femoral condyles.

[0072] A second set of embodiments will now be considered below.

[0073] In these embodiments, the systems and embodiments discussed above (along with additional / alternative embodiments discussed below) are used to assist in total hip arthroplasty surgery. For example, the systems and embodiments may be used to prepare bones (e.g., the pelvis, acetabulum, and femur) and place corresponding implants in a patient.

[0074] Certain landmarks and / or planes may be useful in registering or determining a patient's orientation in the 3D space of an operating room. For example, as part of a computer-assisted navigation workflow during surgery, a system may register or determine the orientation of a patient's anterior pelvic plane (APP) and / or functional pelvic plane (FPP) to determine the patient's orientation on the operating room table during a total hip arthroplasty (THA) surgery.

[0075] The system can provide computer-assisted navigation throughout the entire spectrum of care (pre-operative, intra-operative, and post-operative). Thus, the system can be configured to perform multiple workflows. Some workflows use patient scans (X-rays, computed tomography (CT)) obtained during pre-operative steps.

[0076] In some embodiments of the present disclosure, the system performs an image-less workflow in which preoperative images are not used. Information about the patient's anatomy in the operating room (OR) can be obtained by the surgeon using the system to measure key parameters of the patient's bones. For example, the system's computer platform operates to identify the location of landmarks (e.g., points, axes, and / or surfaces) on the bone and register the locations simultaneously with or after the identification. The locations can be used to define reference planes (e.g., APP and / or FPP), which are used to plan implants and navigate robots and surgical instruments for the THA surgical procedure.

[0077] In some embodiments, the only preoperative use case associated with an image-less workflow may be an initial patient assessment. A surgeon may assess a patient's mobility and health status using sensors (e.g., sensors made by Globus Medical attached to the leg), physical movement, and / or assistance from clinical surveys to determine whether a THA is recommended. The collected data may then be stored and processed by the system before being analyzed by the surgeon to facilitate a final decision. The data may then be reused by an application (e.g., a surgical planning application by Globus Medical) to establish the most appropriate implant surgical plan.

[0078] FIG. 8 illustrates a flowchart for an image-less workflow during the intraoperative portion of a THA surgical procedure, according to some embodiments of the present disclosure.

[0079] In some embodiments, after positioning the patient on the operating room table (step 2000), some of the operations discussed above and below may be performed during step 2002 for positioning the patient and before another step 2004 for intraoperative computer-navigated surgery. In the case of a hip joint, the patient's pelvis or acetabulum is registered to the tracking coordinate system of the camera tracking system 200. As shown in FIG. 1 , the pelvis or acetabulum is registered in an optical coordinate system. In one embodiment, the registration is performed in an image-less modality, without the use of medical images such as X-ray or CT images from an imaging device.

[0080] FIG. 9 illustrates a flowchart of a pre-registration patient preparation process according to some embodiments of the present disclosure.

[0081] The patient preparation process may begin with the patient being positioned on the OR table in a lateral or supine position. The patient's body is prepared for alignment.

[0082] Optionally, in step 3000, an EKG / ECG patch electrode is applied at the distal end of the patient's femur. The EKG / ECG patch electrode may be placed at or slightly below the center of the patella. In some possibly preferred embodiments, the patch location is aligned with the anatomical axis of the femur. This patch may be used at a later stage to obtain the most distal point of the femur under draping. This patch may be used to track the femur in space (e.g., when the patient's leg is moved during surgery) and may also be used to assist in measuring the patient's leg length. However, in some embodiments, this operation (step 3000) is skipped.

[0083] In some embodiments, the EKG / ECG patch electrode comprises an adhesive patch that can be removably attached to the patient. In some preferred embodiments, the patch can be black or dark in color so that it is more visible to the tracking camera. In other embodiments, the patch electrode is not visible to the tracking camera because it is underneath the drape. The patch is not visible to the camera (it is underneath the patient's drape). The patch's geometry (nipple-like) helps the surgeon always touch a single point on the distal portion of the femur (anterior patella region) with a navigated stylus / instrument that is trackable by the tracking camera. This ensures that the surgeon always collects the same point for measuring leg length or medial-lateral offset.

[0084] In step 3002, the patient's body is draped. Then, depending on the surgeon's technique, a navigated pelvic dynamic reference base (DRB) marker array (also referred to herein as a reference element) is placed either within the incision (steps 3006-3008) or outside the incision (step 3004) with the aid of cortical pins drilled into the pelvic bone. In some embodiments, the DRB is oriented so as to be visible by a tracking camera (e.g., a stereo tracking camera) mounted on a camera tracking system (e.g., camera tracking system 200 of FIG. 1) or a headset (e.g., XR headset 150 of FIG. 1).

[0085] In one embodiment, the act of placing the reference element within the incision includes using the system to track and navigate access to the joint space (step 3006), during which the reference element is placed within the incision.

[0086] In an alternative embodiment, the reference element is placed outside the incision (step 3004) and the system is not necessarily used to track and navigate access to the joint space.

[0087] After the reference elements are placed within or outside the incision, data points and axes can be collected on the patient's anatomy with the aid of a navigated instrument and using the pelvic DRB coordinate system as a spatial reference. In addition, two pelvic reference planes can be established to plan implant placement by measuring angular deviations, such as tilt and rotation, of the acetabular cup implant, as shown in Figures 10A and 10B.

[0088] 10A illustrates the radiographic tilt angle measured in the coronal plane of a patient, according to some embodiments of the present disclosure. In some embodiments, the surgeon may palpate or paint the surface of the patient's acetabular socket using a navigated instrument, for example, to determine the center of rotation of the acetabulum, as discussed in more detail below.

[0089] FIG. 10B illustrates the radiographic rotation angle measured relative to the patient's coronal plane, according to some embodiments of the present disclosure.

[0090] The two pelvic reference planes (or coronal or frontal planes) are called the anterior pelvic plane (APP) and the functional pelvic plane (FPP), which are determined or defined using different landmarks and axes, as shown in FIG. 11 and described in more detail below.

[0091] Although the user interface and associated operations are described herein as being performed in a particular order, it should be understood that they may be performed in other orders while still being within the disclosed embodiments (including all embodiments disclosed in this disclosure). Furthermore, it is not necessary for all of the user interface and / or described operations to be performed. Instead, fewer operations may be performed while still being within the disclosed embodiments.

[0092] During the patient registration procedure, landmarks used to register the patient's anatomy can be extracted using either single-point tactile collection or surface painting (resulting in a point cloud of locations).

[0093] FIG. 11 illustrates different views of landmarks and axes for alignment of a patient's functional pelvic plane (FPP) and anterior pelvic plane (APP), according to some embodiments of the present disclosure.

[0094] The landmarks and axes used to align the APP and FPP planes are described in more detail with reference to Figures 12 and 15. In some embodiments, the computer platform instructs the surgeon to palpate these landmarks for the computer platform to acquire or identify.

[0095] FIG. 12 illustrates a flowchart for alignment of a patient's APP and FPP, according to some embodiments of the present disclosure.

[0096] For APP plane registration, the accessibility of the landmarks may depend on the selected patient position on the OR table (i.e., supine or lateral).

[0097] With the patient positioned supine on the OR table, a navigated instrument (in this case, a stylus) can be used to acquire or identify the left anterior superior iliac spine (ASIS) (step 6002), acquire or identify the right ASIS (step 6004), and acquire or identify the femoral symphysis (step 6006). These landmarks (i.e., the left ASIS, right ASIS, and femoral symphysis) can then be used to determine the orientation of the patient's APP.

[0098] Alternatively, if the patient is positioned in a supine or lateral position, the APP may be established using one of two navigated instruments, discussed in more detail below (step 6008).

[0099] For FPP plane registration in the supine or lateral position, one of the navigated instruments described below may be used to establish the coronal plane (step 6010), for example, by obtaining or identifying the patient's superior-inferior, lateral, and / or anterior-posterior axes.

[0100] Below are described two navigated instrument motion workflows that can be used to establish an APP (step 6008) or to establish a coronal plane (step 6010).

[0101] 13A-13C illustrate examples of aligning (ie, establishing) the APP and / or FPP using a tracking marker plane of a navigated instrument, according to some embodiments of the present disclosure.

[0102] The first design (shown in FIGS. 13A-13C) may be a completely passive navigated instrument 1100. The navigated instrument 1100 may include reference points 1160 on a reference element of the navigated instrument 1100. These reference points 1160 may form a navigated instrument tracking marker plane, which is a plane that intersects through these reference points 1160. Note that although four reference points are illustrated in FIGS. 13A-13C, any number of reference points may be used to form the navigated instrument tracking marker plane.

[0103] 13B-13C, the instrument can be positioned by the surgeon so that the plane of reference points is parallel to the APP or FPP of the patient's pelvis. Once the plane is parallel to the APP or FPP, the surgeon can trigger the system to capture this plane (e.g., through the depression of a foot pedal), thereby establishing the APP and / or FPP using the navigated instrument.

[0104] In some embodiments, the tracking marker plane is positioned to be parallel to the APP or FPP while the navigated instrument palpates the patient's landmarks.

[0105] FIG. 14 illustrates an example of aligning the APP and / or FPP using the axis of a navigated instrument and a tracking camera with a built-in inertial measurement unit (IMU), according to some embodiments of the present disclosure.

[0106] This second design (shown in FIG. 14 ) may include: (1) a passive, tracked alignment rod (or bar) 1210 attached to or forming part of the navigated instrument 1200, which can be used by the surgeon to identify the patient's longitudinal axis (i.e., superior-subordinate axis) by aligning the rod 1210 to be parallel to the patient's superior-subordinate axis; and (2) an active, built-in inertial measurement unit (IMU) sensor that measures the gravity vector, which can be used to identify either the anterior-posterior axis of a supine patient or the lateral axis of a lateral patient. This can be determined because when a patient is lying supine on an OR table, the gravity vector can be perpendicular to the coronal plane. Alternatively, when a patient is lying down, the gravity vector can be parallel to the coronal plane.

[0107] In some embodiments, the tracked alignment rod may be held parallel to the patient's superior-inferior axis while palpating the patient's landmarks.

[0108] Alternatively, the data collected from the IMU may be provided by another device in the system, such as the same navigated instrument 1200, or another instrument with an IMU sensor (e.g., a tracked power tool such as a drill, saw handpiece, etc.), another camera, or an XR headset (e.g., XR headset 150 of FIG. 1).

[0109] FIG. 15 illustrates a flowchart of operations for measuring a patient's leg length and offset, according to some embodiments of the present disclosure.

[0110] After APP and / or FPP plane alignment, the initial or preoperative leg length and medial and lateral femoral positioning offsets may be obtained (step 9016) by accessing (step 9014) the hip joint cavity and the distal portion of the femur (see left side of FIG. 15). As shown on the right side of FIG. 15, two points may be obtained or identified to determine the position of the femur relative to the pelvis.

[0111] Optionally, for an initial measurement or a measurement prior to the measurements discussed below, the system may prompt the surgeon to create a landmark on the patient's proximal femur (step 9002). This landmark may correspond to a surgeon-defined landmark, such as a divot on the bony anatomy, which may enable the computer platform to create a line in 3D space for the patch once the patch (e.g., the patch placed in step 3000 of FIG. 9) is also identified (step 9010).

[0112] The femur may be positioned in a known position in step 9004. For example, the system may instruct the surgeon to position the patient's femur in a particular position known to the system.

[0113] In step 9006, the system may identify a first landmark. The first landmark may be located in the greater trochanter region of the proximal femur, as close as possible to the exit point of the anatomical axis of the femur. When identifying the location of the first landmark, the surgeon may need to take care to stay away from the femoral neck bone portion that will be cut and removed during the procedure. The point in space where the first landmark is identified may be recorded in the memory of the system's computer platform (step 9008).

[0114] In step 9010, the system may identify a second landmark. The second landmark is identified / obtained on the distal portion of the femur by locating an EKG patch electrode placed on the patient before draping and palpating with a stylus (step 3000 of FIG. 9). This point in space where the second landmark is identified may be recorded in the system's memory (step 9012).

[0115] Using this information (e.g., the landmarks identified in steps 9006 and 9010), the system (i.e., the computer platform) may be able to determine a leg length delta and offset that identifies how far the patient's leg has moved from the patch.

[0116] FIG. 16 illustrates a flowchart for aligning a patient's pelvis and acetabulum, according to some embodiments of the present disclosure.

[0117] To define the APP and FPP origins, the pelvic acetabular center of rotation is determined by the system, which instructs the surgeon to remove the patient's femoral head from the acetabular socket (step 10002). The acetabular socket can be made accessible by cutting the femoral neck and removing the femoral head from the acetabular socket. In some embodiments, a corkscrew instrument can be used to remove the femoral head from the acetabular socket. The surface of the acetabular socket can then be painted using a navigated instrument (e.g., a stylus) (step 10004).

[0118] FIG. 17 illustrates the operation of painting the acetabular cavity 1302 using a navigated instrument 1300 according to some embodiments of the present disclosure. The surgeon uses the navigated instrument 1300 (e.g., a stylus) to palpate the surface of the acetabular cavity 1302, and a tracking camera continuously measures the position of the ball on the end of the stylus, providing a cloud of points of the measured positions (locations). Simultaneously, the tracking camera may also monitor and track the posture of the patient DRB 116 attached to the pelvis so that the posture of the stylus can be tracked relative to the posture of the patient DRB. Alternatively, the surgeon may then measure a predefined number or percentage of points by palpating them one by one. Based on these points and the tracking data of the stylus and patient DRB, the center of rotation of the pelvic acetabulum is determined. Additionally, based on these points, the surface of the acetabular cavity can be registered to the system, and / or a 3D model can be generated or modified based on these points.

[0119] The acetabular socket shape can then be reconstructed by the system (e.g., in a 3D model) based on the cloud of measured points, using, for example, outlier removal and other algorithms for surface fitting.

[0120] Optionally, the deepest point within the acetabular cavity may be identified or acquired (step 10006) to provide information regarding the maximum acetabular reaming depth. For example, the ball of a stylus may be pressed into the acetabular cavity, and the identified deepest point may be acquired or identified by the system as the deepest point within the acetabular cavity. Alternatively, when the acetabular cavity is painted with a navigated instrument, the deepest point within the acetabular cavity may be determined to correspond to the deepest point of the points identified or acquired while painting the acetabular cavity. In some embodiments, step 10006 may be the last step suggested to the surgeon to register the patient for the image-less workflow.

[0121] In a similar manner to preoperative patient assessment, postoperative patient assessment can be performed by the surgeon to evaluate the quality of the THA surgery and its benefits to the patient. The workflow can include, for example, a patient mobility assessment using data collected from body movement and sensor feedback (e.g., attached to the leg), which can be compared to a clinical survey to confirm the patient's health status. All collected postoperative information can be automatically compared by the system with the preoperative information.

[0122] 18 illustrates a user interface for a planning view that displays a graphical representation of bones with extracted (e.g., aligned) landmarks (shown as bright dots) and a graphical representation of which surfaces were acquired through tactile actions. Although the image represents a knee, a similar image could be used to display the pelvis with the acetabulum indicated and landmarks acquired.

[0123] Bone palpation techniques can be used in many ways to acquire and extract landmarks, and can vary based on whether the technique is for a computer-assisted (e.g., robotic) versus manually navigated procedure, and whether the technique is used in conjunction with an image-less or CT-based procedure.

[0124] For example, in a patient registration workflow for a computer-assisted or manually navigated procedure using image-less or CT-based images, bone palpation actions can be used to acquire and extract landmarks.

[0125] In a workflow for displaying a bone 3D model for a computer-assisted navigation procedure, in the case of an image-less process, a general bone model can have updated dimensions based on landmarks acquired and extracted through bone palpation, or in the case of CT-based image processing, a reconstructed 3D model of the patient's anatomy can be generated based on preoperative CT images and landmarks acquired and extracted through bone palpation.

[0126] In a workflow for displaying a bone 3D model for a manually navigated procedure, in the case of an image-less process, the general bone model may not have updated dimensions based on landmarks acquired and extracted through bone palpation, or in the case of CT-based image processing, a reconstructed 3D model of the patient's anatomy may be generated based on preoperative CT images, which may or may not be based on landmarks acquired and extracted through bone palpation.

[0127] In a workflow for displaying a navigated instrument along with a bone model for a computer-assisted navigation procedure, in the case of an image-less process, the navigated instrument may not be displayed along with the bone 3D model, or in the case of CT-based image processing, the navigated saw blade may be displayed along with the bone 3D model.

[0128] In a workflow for displaying a bone 3D model for a manually navigated procedure, in the case of no image or CT-based imaging, a navigation guide can be displayed along with the bone 3D model to guide the user for cutting block location pin insertion.

[0129] FIG. 20 illustrates a flowchart of additional or alternative operations performed by a computer platform of a system for computer-assisted navigation during a surgical procedure on a patient (e.g., computer platform 400 of FIG. 4 ), according to some embodiments of the present disclosure.

[0130] In some embodiments, the computer platform is operable to identify a set of locations where a navigated instrument (e.g., the stylus of FIG. 5 or the navigated instrument of FIGS. 13A-14) is palpating defined landmarks on the surface of the patient's pelvic bone. For example, this operation may be performed similarly to operations / steps 6002-6010 of FIG. 12, 9006 and 9010 of FIG. 15, and 10004-10006 of FIG. 16.

[0131] The computer platform may be further operable to determine a center of rotation for the patient's pelvis-acetabulum based on the set of identified locations where the navigated instrument is palpating landmarks. For example, determining the center of rotation for the pelvis-acetabulum may be performed similar to at least some of the operations / steps performed with respect to FIG.

[0132] The computer platform may be further operable to determine the orientation of the patient's anterior pelvic plane (APP) and / or functional pelvic plane (FPP) based on the identified set of locations where the navigated instrument is palpating landmarks and based on the determined center of rotation for the pelvis acetabulum. For example, these operations may be performed similarly to those of FIG. 12 .

[0133] In some embodiments, the landmarks are defined as the right ASIS, left ASIS, and pubic symphysis of the patient's pelvic bones to determine the orientation of the APP. Alternatively, in some embodiments, the computer platform is further operable to identify an inferior-superior axis, a left-right axis, and / or an anterior-posterior axis of the patient's pelvic bones to determine the orientation of the APP based on the identified set of locations where the navigated instrument is palpating the landmarks.

[0134] In some embodiments, to determine the orientation of the FPP based on the identified set of locations where the navigated instrument is palpating landmarks, the computer platform is further operable to identify an inferior-superior, left-right, and / or anterior-posterior axis of the patient's pelvic bone. For example, identifying the superior-superior, left-right, and / or anterior-posterior axis of the patient's pelvic bone may be performed similarly to that described with reference to FIG. 14. In some embodiments, when determining the center of rotation for the pelvic acetabulum, the landmark is defined as the deepest point of the acetabular fossa of the pelvic bone.

[0135] In some embodiments, the superior-inferior axis is identified by a rod on the navigated instrument that is parallel to the superior-inferior axis while the navigated instrument is palpating the landmark.

[0136] In some embodiments, the computer platform is further operable to identify another location where the navigated instrument palpates the deepest point on the acetabulum. The computer platform may be further operable to determine a maximum acetabular reaming depth based on the identified another location where the navigated instrument palpates the deepest point on the acetabulum.

[0137] In some embodiments, the orientation of the APP and / or FPP and the center of rotation of the pelvis acetabulum are determined without the use of preoperative images.

[0138] In some embodiments, the computer platform is further operable to align the determined orientation of the APP and / or the FPP with an algorithm for computer-assisted navigation during surgery. Additionally, in some embodiments, the computer platform is further operable to display a graphical representation of the determined orientation of the APP and / or the FPP in a planning view for computer-assisted navigation during surgery.

[0139] In some embodiments, after determining the orientation of the APP and / or FPP based on the set of identified locations where the navigated instrument palpates landmarks and based on the determined center of rotation for the pelvis-acetabulum, the computer platform is further operable to identify a first location, distinct from the set of locations, where the navigated instrument palpates a greater trochanter region of the proximal femur at least proximal to the exit point of the anatomical axis of the femur. In these embodiments, the computer platform is further operable to identify a second location, distinct from the set of locations, where the navigated instrument palpates a distal portion of the femur where an electrocardiogram (EKG) patch electrode is located on the patient. Additionally, in some embodiments, the computer platform is further operable to determine the patient's leg length and medial-lateral femoral positioning offset based on the identified first location and the identified second location.

[0140] Additionally, in these embodiments, the identification of another location, separate from the set of locations, where the navigated instrument palpates the greater trochanter region of the proximal femur at least proximal to the exit point of the anatomical axis of the femur, is performed after the patient's femur is positioned in a known position.

[0141] In some embodiments, the navigated instrument comprises a ball-tip stylus. For example, the ball-tip stylus may correspond to the ball-tip stylus of FIG. 5. The computer platform may be operable to identify a set of locations where the navigated instrument is touching landmarks by identifying locations of reference points of reference elements on the ball-tip stylus in images acquired from tracking cameras having at least partially overlapping fields of view that image the ball-tip stylus with the ball on the ball-tip stylus touching a bone surface. The computer platform may further be operable to identify the set of locations by determining locations of centers of the ball based on the locations of the reference points of the reference elements, define an offset acquired bone surface based on mathematically connecting the locations of the ball centers, determine a local normal vector to the offset acquired surface for the ball center locations, and translate the offset acquired bone surface along the local normal vector based on a radius of the ball toward the bone surface to define the acquired bone surface.

[0142] In some embodiments, the computer platform is further operable to determine a center of rotation of the patient's pelvis acetabulum based on the set of identified locations where the navigated instrument palpates landmarks, including the interior of the patient's acetabular fossa, and to determine the origin of the APP and / or FPP based on the center of rotation of the patient's pelvis acetabulum. In these embodiments, determining the center of rotation of the patient's pelvis acetabulum can be performed after the femoral head of the patient's femur is removed from the acetabular fossa. Additionally or alternatively, the computer platform is further operable to generate a model of the shape of the acetabular fossa based on the set of identified locations where the navigated instrument palpates landmarks, including the interior of the patient's acetabular fossa.

[0143] In some embodiments, the computer platform is further operable to align at least one of the determined orientation of the APP, the determined orientation of the FPP, and the determined center of rotation with respect to the pelvic acetabulum in an algorithm for computer-assisted navigation during surgery.

[0144] In some embodiments, the orientation of the patient's APP and / or FPP is determined further based on the gravity vector of the system's tracking camera's built-in inertial measurement unit (IMU).

[0145] As described above, and in summary, there can be at least two different methods for aligning the pelvis to the tracking coordinates (e.g., optical coordinate system) of a tracking system without images. In both methods, the center of rotation of the acetabulum is determined tactilely, for example, by either touching multiple points inside the acetabulum with the navigated instrument / probe 1100 or by continuous surface painting without lifting the navigated instrument / probe 1100. In the first method, the FPP is derived by the physician aligning a plane or axis defined by the navigated instrument along or parallel to the FPP. Once the center of rotation and FPP are determined, the system (either the navigation system or the combined navigation and robotic system 100) has enough information to align the acetabulum in the coordinate system (e.g., optical coordinate system) of the camera tracking system 200. The alignment may enable the navigation system or robotic system to track any navigated instrument or end effector, or any tool attached to an end effector, relative to the pelvis as tracked by the patient dynamic reference base 116 attached to the pelvis.

[0146] In a second embodiment, the APP is derived by touching various known points (e.g., the left and right ASIS and pubic symphysis) with a navigated instrument, or by the physician aligning a plane or axis defined by the navigated instrument along or parallel to the APP. Once the center of rotation and APP are determined, the system (either the navigation system or the combined navigation and robotics system 100) has enough information to align the acetabulum in the coordinate system (e.g., the optical coordinate system) of the camera tracking system 200.

[0147] In both of the methods described above, the tracking system can constantly monitor and track the posture of the patient DRB 116 attached to the pelvis while also tracking the navigated instrument 1100 so that the posture of the instrument can be tracked relative to the posture of the patient DRB for the purpose of aligning the pelvis relative to the patient DRB 116 at least in the tracking coordinate system of the camera tracking system 200.

[0148] Further definitions and embodiments: In the above description of various embodiments of the inventive concept, it should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the inventive concept. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted to have a meaning consistent with their meaning in the context of this specification and related art, and should not be interpreted in the idealized or overly formal sense explicitly defined herein.

[0149] When an element is referred to as being "connected," "coupled," or "responsive" to another element, or variations thereof, it may be directly connected, coupled, or responsive to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected," "directly coupled," or "directly responsive" to another element, or variations thereof, there are no intervening elements present. Like numbers refer to like elements throughout. Furthermore, as used herein, "coupled," "connected," "responsive," or variations thereof can include being wirelessly coupled, connected, or responsive. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. Well-known features or structures may not be described in detail for the sake of brevity and / or clarity. The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0150] In this specification, terms such as first, second, and third may be used to describe various elements / operations, but it is understood that these elements / operations should not be limited by these terms. These terms are used only to distinguish one element / operation from another. Thus, a first element / operation in some embodiments may be referred to as a second element / operation in other embodiments without departing from the teachings of the inventive concept. The same reference numbers or characters refer to the same or similar elements throughout this specification.

[0151] As used herein, the words "comprise," "comprising," "comprises," "include," "including," "includes," "have," "has," "having," or variations thereof, are open-ended and refer to the inclusion of one or more stated features, integers, elements, steps, components, or functions, but do not exclude the presence or addition of one or more other features, integers, elements, steps, components, functions, or groups thereof. Furthermore, as used herein, the common abbreviation "eg," derived from the Latin phrase "exempli gratia," may be used to introduce or designate a general example or examples of a previously mentioned item and is not intended to be limiting of such items. The common abbreviation "ie," derived from the Latin phrase "id est," may be used to designate a particular item from a more general list.

[0152] Exemplary embodiments are described herein with reference to block diagrams and / or flowchart illustrations of computer-implemented methods, apparatus (systems and / or devices), and / or computer program products. It will be understood that blocks of the block diagrams and / or flowchart illustrations, and combinations of blocks in the block diagrams and / or flowchart illustrations, can be implemented by computer program instructions executed by one or more computer circuits. These computer program instructions can be provided to general-purpose computer circuits, special-purpose computer circuits, and / or processor circuits of other programmable data processing devices to produce machines such that the instructions, executed via a processor of a computer and / or other programmable data processing device, transform and control transistors, values stored in memory locations, and other hardware components within such circuits to implement the function(s) / operations specified in the block diagram and / or flowchart block(s), thereby forming means (functions) and / or structure for performing the function(s) / operations specified in the block diagram and / or flowchart block(s).

[0153] These computer program instructions may also be stored on a tangible computer-readable medium that can instruct a computer or other programmable data processing apparatus to function in a particular manner to produce an article of manufacture that includes instructions that cause the instructions to implement the function / act specified in the flowchart and / or block diagram block or blocks. Thus, embodiments of the inventive concepts may be embodied in hardware and / or software (including firmware, resident software, microcode, etc.) running on a processor, such as a digital signal processor, which may collectively be referred to as a "circuit," "module," or variations thereof.

[0154] It should also be noted that in some alternative implementations, the functions / acts noted in the blocks may also occur in an order different from that noted in the flowcharts. For example, two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending on the functions / acts involved. Furthermore, the functionality of a given block in the flowcharts and / or block diagrams may be separated into multiple blocks, or the functionality of two or more blocks in the flowcharts and / or block diagrams may be at least partially integrated. Finally, other blocks may be added / inserted between the illustrated blocks and / or blocks / acts may be omitted without departing from the scope of the inventive concept. Furthermore, while some diagrams include arrows on communication paths to indicate a primary direction of communication, it should be understood that communication may occur in the opposite direction to the depicted arrows.

[0155] Numerous variations and modifications can be made to the embodiments without substantially departing from the principles of the inventive concept. All such variations and modifications are intended to be included herein within the scope of the inventive concept. Accordingly, the above disclosed subject matter should be considered illustrative, and not limiting, and the accompanying examples of embodiments are intended to cover all such modifications, enhancements, and other embodiments that fall within the spirit and scope of the inventive concept. Thus, to the maximum extent permitted by law, the scope of the inventive concept should be determined by the broadest permissible interpretation of this disclosure, including the following examples of embodiments and their equivalents, and is not limited or constrained by the foregoing detailed description.

Claims

1. 1. A system for computer-assisted navigation during surgery, comprising: identifying a set of locations on a surface of the patient's pelvic bone at which the navigated instrument is moving while the navigated instrument is being tracked by a tracking system; determining a center of rotation for the patient's pelvis-acetabulum based on the set of identified locations; determining an anterior pelvic plane (APP) and / or functional pelvic plane (FPP) orientation of the patient using the navigated instrument while the tracking system is tracking the navigated instrument; aligning the pelvis in a coordinate system of the tracking system based on the determined APP or FPP and the determined center of rotation for the pelvis acetabulum; A system comprising a computer platform operable to:

2. 2. The system of claim 1, wherein to determine the orientation of the APP, the computer platform records the locations of the right anterior superior iliac spine, the left anterior superior iliac spine, and the pubic symphysis of the patient's pelvic bone based on tracking of the navigated instrument by the tracking system.

3. To determine the orientation of the FPP, the computer platform:

10. The system of claim 1, further operable to identify an inferior-superior, lateral, and / or anterior-posterior axis of the patient's pelvic bone based on tracking of the navigated instrument by the tracking system.

4. The system of claim 3 , wherein the computer platform identifies the superior-inferior axis by recording a pose of the navigated instrument when a rod on the navigated instrument is parallel to the superior-inferior axis.

5. To determine the orientation of the APP, the computer platform:

10. The system of claim 1, further operable to record the posture of the navigated instrument when the navigated instrument identifies an inferior-superior, lateral, and / or anterior-posterior axis of the patient's pelvic bone.

6. 10. The system of claim 1, wherein when identifying a set of locations on a surface of a patient's pelvic bone, the computer platform is operable to continuously track the pose of the navigated instrument and a patient dynamic reference base attached to the pelvis.

7. The computer platform includes: identifying another location where the navigated instrument contacts the deepest point on the acetabulum; determining a maximum acetabular reaming depth based on the identified alternative location; The system of claim 1 further operable to:

8. The system of claim 1 , wherein the orientation of the APP and / or the FPP and the center of rotation of the pelvis acetabulum are determined without the use of pre-operative images.

9. The computer platform includes: The system of claim 1 , further operable to display a graphical representation of the determined orientation of the APP and / or the FPP in a planning view for computer-assisted navigation during surgery.

10. The computer platform includes: identifying a first location, distinct from the set of locations, at which the navigated instrument penetrates a greater trochanter region of the proximal femur at least proximal to an exit point of an anatomical axis of the femur; identifying a second location, distinct from the set of locations, at which the navigated instrument vibrates a known location on the distal portion of the femur; determining a leg length and a medial-lateral femoral positioning offset of the patient based on the identified first location and the identified second location; The system of claim 1 further operable to:

11. 11. The system of claim 10, wherein the computer platform identifies the first location after the patient's femur is positioned in a known position to confirm a planned leg length.

12. The system of claim 1 , wherein the navigated instrument comprises a ball-tip stylus.

13. The computer platform includes: Identifying a location of a reference point of the ball-tip stylus within an image acquired from a camera of the tracking system; determining a location of a center of the ball based on the location of the reference point of the ball-tip stylus; defining an offset acquired bone surface based on mathematically connecting the locations of the centers of the balls; determining a local normal vector to the offset-acquired surface for the location of the center of the ball; and translating the offset-acquired bone surface along the local normal vector towards the surface of the bone based on a radius of the ball to define an acquired bone surface.

14. 14. The system of claim 13, wherein the computer platform is operable to identify the set of locations by simultaneously tracking the reference point of the ball-tip stylus and a patient dynamic reference base attached to the pelvis.

15. The system of claim 1 , wherein the computer platform determines the center of rotation for the pelvic acetabulum after the femoral head of the patient's femur is removed from an acetabular socket.

16. The computer platform includes: The system of claim 1 , further operable to generate a model of the shape of the acetabular fossa based on the set of identified locations.

17. The computer platform includes:

10. The system of claim 1, further operable to align at least one of the determined orientation of the APP, the determined orientation of the FPP, and the determined center of rotation with respect to the pelvic acetabulum in an algorithm for computer-assisted navigation during surgery.

18. The system of claim 1 , wherein the computer platform is further operable to determine the orientation of the APP or the FPP based on a gravity vector of an integrated inertial measurement unit (IMU) of the tracking system.

19. 1. A computer program product comprising: a non-transitory computer-readable medium storing instructions executable by at least one processor to perform operations for computer-assisted navigation during a surgical procedure, the operations comprising: identifying a set of locations on a surface of the patient's pelvic bone at which the navigated instrument is moving while the navigated instrument is being tracked by a tracking system; determining a center of rotation for the patient's pelvis-acetabulum based on the set of identified locations; determining an anterior pelvic plane (APP) and / or functional pelvic plane (FPP) orientation of the patient using the navigated instrument while the tracking system is tracking the navigated instrument; A computer program product that aligns the pelvis in a coordinate system of the tracking system based on the determined APP or the FPP and the determined center of rotation for the pelvis acetabulum.

20. 20. The computer program product of claim 19, wherein the computer-readable medium stores instructions for the processor to determine the orientation of the FPP by identifying a pose of the navigated instrument by the tracking system while the navigated instrument is positioned along a line parallel to the FPP.

Images