System and method for bone model registration using adaptive soft tissue thickness - Patents.com

Abstract

A system and method for planning and assisting orthopedic surgical procedures includes a computing device and a robotic surgical device. The computing device defines a surgical coordinate system relative to a patient's bone and captures a plurality of point locations within the surgical coordinate system. The plurality of point locations includes a first point location representing a location on a soft tissue surface overlying a portion of the patient's bone. The computing device identifies an estimated soft tissue thickness value for each of the plurality of point locations and registers a three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness value. The computer system can control the robotic surgical device according to the registered bone model.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Non-Provisional Patent Application No. 18 / 106,892, filed February 7, 2023, the contents of which are incorporated herein by reference in their entirety.

[0002] FIELD OF THE INVENTION The present disclosure relates generally to orthopaedic surgical tools and systems, and more particularly to systems and methods for aligning a bone model with a patient's anatomy for use during an orthopaedic surgical procedure. [Background technology]

[0003] Joint arthroplasty is a well-known surgical procedure that replaces a diseased and / or damaged natural joint with an artificial joint, which may include one or more orthopedic implants. To facilitate replacing the natural joint with the artificial joint, orthopedic surgeons may use various orthopedic surgical instruments, such as, for example, surgical saws, cutting guides, reamers, broaches, drill guides, drills, positioners, insertion tools, and / or other surgical instruments. Surgeons may use manual instruments, such as cutting blocks or other cutting guides, to perform various resections in orthopedic surgical procedures. Alternatively, or in addition, surgeons may use computer-assisted surgical navigation systems, such as robotic-assisted surgical systems, to perform various resections in orthopedic surgical procedures. Summary of the Invention [Means for solving the problem]

[0004] According to one aspect, a bone model registration method performed by a computing device may include defining a surgical coordinate system for a patient's bone, capturing a plurality of point locations within the surgical coordinate system, identifying an estimated soft tissue thickness value for each of the plurality of point locations, and registering a three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness value. Each of the plurality of point locations may be associated with an anatomical landmark of the patient's bone. The plurality of point locations may include a first point location representing a location on a soft tissue surface overlying a portion of the patient's bone.

[0005] In some embodiments, capturing the plurality of point locations may include tracking a location of a registration tool with a pointer using a camera array coupled to the computing device. The registration tool pointer may be in direct contact with the soft tissue surface but not with the patient's bone surface while the first point location is being captured. In some embodiments, the plurality of point locations may further include a second point location captured while the registration tool pointer is in direct contact with the patient's bone. In some embodiments, identifying an estimated soft tissue thickness value for each of the plurality of point locations may include identifying the estimated soft tissue thickness value for the first point location as a number greater than zero and identifying the estimated soft tissue thickness value for the second point location as zero. In some embodiments, capturing the plurality of point locations may include moving the registration tool pointer along the patient's bone surface or along the soft tissue surface to capture a point cloud associated with anatomical landmarks.

[0006] In some embodiments, identifying an estimated soft tissue thickness value for each of the plurality of point locations may include receiving one or more estimates of soft tissue thickness from a surgeon during the orthopaedic surgical procedure. In some embodiments, identifying an estimated soft tissue thickness value for each of the plurality of point locations may include retrieving one or more initial estimated soft tissue thickness values ​​associated with the plurality of point locations from a memory device.

[0007] In some embodiments, the method may further include receiving an updated estimated soft tissue thickness value for at least one of the plurality of point locations, and realigning the three-dimensional model of the patient's bone within a surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness values, including the at least one updated estimated soft tissue thickness value.

[0008] In some embodiments, registering the three-dimensional model may include determining, for each of a plurality of point locations, a distance between the point location and a corresponding point from the three-dimensional model expanded by an estimated soft-tissue thickness value associated with the point location to determine a set of distances associated with a transformation of the three-dimensional model. Registering the three-dimensional model may further include optimizing the set of distances by iteratively adjusting the transformation of the three-dimensional model to improve the quality of the registration of the three-dimensional model. Registering the three-dimensional model may further include optimizing the set of distances by iteratively adjusting the estimated soft-tissue thickness value associated with one or more of the plurality of point locations to improve the quality of the registration of the three-dimensional model.

[0009] In some embodiments, the method may further include, after registering the three-dimensional model, displaying a representation of the three-dimensional model within the surgical coordinate system. In some embodiments, the method may further include displaying a plurality of point locations relative to the displayed representation of the three-dimensional model. Displaying the plurality of point locations relative to the displayed representation of the three-dimensional model may include color-coding each of the plurality of point locations according to a distance between each point location and a corresponding point from the three-dimensional model extended by an estimated soft tissue thickness value associated with the point location.

[0010] In some embodiments, the method may further include, after registering the three-dimensional model, capturing a verification point location while a pointer of the registration tool is in contact with a soft tissue surface overlying a portion of the patient's bone, displaying the verification point location relative to a displayed representation of the three-dimensional model, and displaying a difference between the verification point location and a corresponding point from the three-dimensional model expanded by an estimated soft tissue thickness value associated with the corresponding point.

[0011] In some embodiments, displaying the difference between the verification point location and a corresponding point from the three-dimensional model augmented by an estimated soft tissue thickness value associated with the corresponding point may include displaying the verification point location using a first color if the difference is less than a first threshold, and displaying the verification point location using a second color different from the first color if the difference is greater than the first threshold.

[0012] In some embodiments, the method may further include creating a three-dimensional model based on the one or more preoperative medical images. In some embodiments, the method may further include, after registering the three-dimensional model, controlling the robotic surgical device within the surgical coordinate system based on the three-dimensional model.

[0013] According to another aspect, an orthopaedic surgical system may include a computer system configured to define a surgical coordinate system for a patient's bone, capture a plurality of point locations within the surgical coordinate system, identify an estimated soft tissue thickness value for each of the plurality of point locations, and register a three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness value. Each of the plurality of point locations may be associated with an anatomical landmark of the patient's bone. The plurality of point locations may include a first point location representing a location on a soft tissue surface overlying a portion of the patient's bone.

[0014] In some embodiments, the system may further include a registration tool having a pointer configured to contact various locations on the patient's anatomy. The system may further include a camera array coupled to the computing device. The computing device may be configured to capture multiple point locations by tracking the location of the registration tool using the camera array. The computing device may be configured to capture a first point location while the pointer of the registration tool is in direct contact with a soft tissue surface but not in direct contact with a bone of the patient. [Brief explanation of the drawings]

[0015] The concepts described herein are illustrated by way of example, and not by way of limitation, in the accompanying drawings. For simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. Where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements. The detailed description makes specific reference to the following drawings: [Figure 1] 1 is a schematic diagram of a system for planning and assisting orthopaedic surgical procedures. [Figure 2] FIG. 2 is a simplified flow diagram of a method for an orthopedic surgical procedure including bone model registration that may be performed by the surgical planning and assistance device of FIG. [Figure 3A] FIG. 2 is a simplified flow diagram of a method for bone model registration with surgeon-directed cartilage thickness estimation that may be performed by the surgical planning and assistance device of FIG. 1. [Figure 3B] FIG. 2 is a simplified flow diagram of a method for bone model registration with surgeon-directed cartilage thickness estimation that may be performed by the surgical planning and assistance device of FIG. 1. [Figure 3C] FIG. 2 is a simplified flow diagram of a method for bone model registration with surgeon-directed cartilage thickness estimation that may be performed by the surgical planning and assistance device of FIG. 1. [Figure 4A]FIG. 2 is a simplified flow diagram of a method for bone model registration with automated cartilage thickness estimation that may be performed by the surgical planning and assistance device of FIG. 1. [Figure 4B] FIG. 2 is a simplified flow diagram of a method for bone model registration with automated cartilage thickness estimation that may be performed by the surgical planning and assistance device of FIG. 1. [Figure 5] 10A-10C are schematic diagrams illustrating potential embodiments of user interfaces for bone model alignment that may be provided by the surgical planning and assistance device of FIG. 1 in conjunction with the methods of FIGS. 2-4B during the performance of various orthopedic surgical procedures. [Figure 6] 10A-10C are schematic diagrams illustrating potential embodiments of user interfaces for bone model alignment that may be provided by the surgical planning and assistance device of FIG. 1 in conjunction with the methods of FIGS. 2-4B during the performance of various orthopedic surgical procedures. [Figure 7] 10A-10C are schematic diagrams illustrating potential embodiments of user interfaces for bone model alignment that may be provided by the surgical planning and assistance device of FIG. 1 in conjunction with the methods of FIGS. 2-4B during the performance of various orthopedic surgical procedures. [Figure 8] 10A-10C are schematic diagrams illustrating potential embodiments of user interfaces for bone model alignment that may be provided by the surgical planning and assistance device of FIG. 1 in conjunction with the methods of FIGS. 2-4B during the performance of various orthopedic surgical procedures. [Figure 9] 10A-10C are schematic diagrams illustrating potential embodiments of user interfaces for bone model alignment that may be provided by the surgical planning and assistance device of FIG. 1 in conjunction with the methods of FIGS. 2-4B during the performance of various orthopedic surgical procedures. [Figure 10] 10A-10C are schematic diagrams illustrating potential embodiments of user interfaces for bone model alignment that may be provided by the surgical planning and assistance device of FIG. 1 in conjunction with the methods of FIGS. 2-4B during the performance of various orthopedic surgical procedures. DETAILED DESCRIPTION OF THE INVENTION

[0016] While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that it is not the intention of this disclosure to limit the concepts of the present disclosure to the particular forms disclosed, but rather the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure and the appended claims.

[0017] Terms denoting anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, etc., may be used throughout this specification with respect to the orthopedic implants or prostheses and surgical instruments described herein, as well as with reference to a patient's natural anatomy. Such terms have well-understood meanings both in the study of anatomy and in the field of orthopedic surgery. Use of such anatomical reference terms in the written description and claims is intended to be consistent with their well-understood meanings, unless otherwise specified.

[0018] References herein to "one embodiment," "embodiment," "exemplary embodiment," etc. indicate that the embodiment being described may include a particular element, structure, or feature, but not all embodiments necessarily include that particular element, structure, or feature. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular element, structure, or feature is described in connection with one embodiment, it is believed to be within the knowledge of one of ordinary skill in the art to implement such element, structure, or feature in connection with other embodiments, whether or not explicitly described. Additionally, it should be understood that items listed in the form "at least one of A, B, and C" can mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). Similarly, items listed in the form "at least one of A, B, or C" can mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

[0019] The disclosed embodiments may be implemented as hardware, firmware, software, or any combination thereof, as the case may be. The disclosed embodiments may also be implemented as instructions carried by or stored on a transient or non-transitory machine-readable (e.g., computer-readable) storage medium that may be read and executed by one or more processors. A machine-readable storage medium may be embodied as any storage device, mechanism, or other physical structure for storing or transmitting information in a form readable by a machine (e.g., a volatile or non-volatile memory, a media disk, or other media device).

[0020] In the figures, some structural or method elements may be shown in a specific arrangement and / or order. However, it should be recognized that such specific arrangement and / or order may not be required. Rather, in some embodiments, such elements may be arranged in a different manner and / or order than that shown in the illustrative figures. Additionally, the inclusion of a structural or method element in a particular figure does not imply that such element is required in all embodiments, and in some embodiments, it may not be included or may be combined with other elements.

[0021] 1 , surgical system 100 is used during an orthopedic surgical procedure, such as a total knee arthroplasty (TKA), total hip arthroplasty (THA), or total shoulder arthroplasty (TSA) procedure. During the procedure, an orthopedic surgeon performs registration of the patient's anatomy using system 100. During registration, system 100 determines the thickness of the cartilage or other soft tissue overlying the patient's bones using a surgeon-driven or automated process, as described further below. Registration aligns a three-dimensional model of the patient's bony anatomy with the patient's actual anatomy, for example, by aligning the model to a surgical coordinate system. The surgeon or other user continues to create and / or modify the surgical plan based on the alignment, and the robotic surgical device 104 can be controlled based on the surgical plan during the surgical procedure, for example, by robotically constraining the surgical saw 106 to one or more predefined safety zones defined by the surgical plan.

[0022] Thus, system 100 performs bone model registration while accounting for variable cartilage / soft tissue thickness, which is an improvement over conventional processes. For example, compared to certain typical bone model registration processes, system 100 does not require the surgeon to remove or drill cartilage / soft tissue to contact the bone while performing the registration. Thus, system 100 may reduce the required surgical time and / or reduce surgical variability. As another example, system 100 does not require the use of a cartilage model derived from the bone model (e.g., based on a statistical shape model or other approach). Compared to typical approaches that use a cartilage model, system 100 may provide improved registration accuracy, and system 100 may account for idiosyncrasies such as localized cartilage damage that are not included in the cartilage model.

[0023] As shown in FIG. 1 , system 100 includes a surgical planning and assistance device 102 and a robotic surgical device 104, as well as multiple alignment tools 108. Surgical planning and assistance device 102 may be embodied as any type of computer system capable of performing the functions described herein. For example, surgical planning and assistance device 102 may be embodied as, without limitation, a workstation, a desktop computer, a laptop computer, a dedicated computing device, a server, a rack-mounted server, a blade server, a network appliance, a web appliance, a tablet computer, a smartphone, a consumer electronics device, a distributed computing system, a multiprocessor system, and / or any other computing device capable of performing the functions described herein. Additionally, while surgical planning and assistance device 102 is illustrated in FIG. 1 as being embodied as a single computer, it should be understood that surgical planning and assistance device 102 may be embodied as multiple devices cooperating with each other to facilitate the functions described below. For example, in some embodiments, system 100 may include a base station and a satellite station, or other combination of computing devices. Additionally or alternatively, in some embodiments, the surgical planning and assistance device 102 may be embodied as a "virtual server" formed from multiple computer systems distributed across a network and running in a public or private cloud.

[0024] 1 , the illustrative surgical planning and assistance device 102 includes a processor 120, an I / O subsystem 122, a memory 124, a data storage device 126, and a communications subsystem 128. Of course, the surgical planning and assistance device 102, in other embodiments, may include other or additional components, such as those typically found in a computer (e.g., various input / output devices). Additionally, in some embodiments, one or more of the illustrative components may be incorporated into or form a portion of another component. For example, the memory 124, or a portion thereof, may be incorporated into the processor 120 in some embodiments.

[0025] The processor 120 may be embodied as any type of processor or controller capable of performing the functions described herein. For example, the processor may be embodied as a single or multi-core processor, digital signal processor, microcontroller, or other processor or processing / control circuitry. Similarly, the memory 124 may be embodied as any type of volatile or non-volatile memory or data storage capable of performing the functions described herein. During operation, the memory 124 may store various data and software, such as an operating system, applications, programs, libraries, and drivers, used during operation of the surgical planning and assistance device 102. The memory 124 is communicatively coupled to the processor 120 via an I / O subsystem 122, which may be embodied as circuits and / or components for facilitating input / output operations by the processor 120, the memory 124, and other components of the surgical planning and assistance device 102. For example, the I / O subsystem 122 may be embodied as or may otherwise include a memory controller hub, an input / output control hub, firmware devices, communication links (i.e., point-to-point links, bus links, wires, cables, light guides, printed circuit board traces, etc.), and / or other components and subsystems for facilitating input / output operations. In some embodiments, the I / O subsystem 122 may form part of a system-on-a-chip (SoC) and may be incorporated into a single integrated circuit chip along with the processor 120, memory 124, and other components of the surgical planning and assistance device 102.

[0026] The data storage device 126 may be embodied as any type of device or devices configured for short-term or long-term storage of data, such as, for example, memory devices and circuits, memory cards, hard disk drives, solid-state drives, or other data storage devices. The communications subsystem 128 of the surgical planning and assistance device 102 may be embodied as any communications circuitry, device, or collection thereof capable of enabling communications between the surgical planning and assistance device 102 and a remote device. The communications subsystem 128 may be configured to perform such communications using any one or more communications technologies (e.g., wired or wireless communications) and associated protocols (e.g., Ethernet, Bluetooth, Wi-Fi, WiMAX, etc.).

[0027] 1 , the surgical planning and assistance device 102 includes a display 130. The display 130 may be embodied as any type of display capable of displaying digital images or other information, such as a liquid crystal display (LCD), a light emitting diode (LED), a plasma display, a cathode ray tube (CRT), or other type of display device. In some embodiments, the display 130 may be coupled to a touch screen that allows for user interaction with the surgical planning and assistance device 102.

[0028] The surgical planning and assistance device 102 further includes one or more cameras 132. Each of the cameras 132 may be embodied as a digital camera or other digital imaging device coupled to the surgical planning and assistance device 102. Each camera 132 includes an electronic image sensor such as an active-pixel sensor (APS), e.g., a complementary metal-oxide-semiconductor (CMOS) sensor, or a charge-coupled device (CCD). In an illustrative embodiment, multiple cameras 132 are arranged in an array, so that the distance to an object imaged by the camera 132 can be determined.

[0029] The robotic surgical device 104 may be embodied as any type of robot capable of performing the functions described herein. Illustratively, the robotic surgical device 104 is embodied as a robotic arm that may be attached to an operating table or otherwise positioned near a patient during an orthopedic surgical procedure. The robotic surgical device 104 includes a surgical tool 106, illustratively embodied as a surgical saw 106. In use, the robotic surgical device 104 supports the surgical saw 106 and, as described further below, may constrain movement of the surgical saw 106 within a resection plane specified in a surgical plan. The surgeon may activate the surgical saw 106 and perform a resection using the surgical saw 106 while the robotic surgical device 104 constrains movement of the surgical saw 106 to the resection plane. Although illustrated with a surgical saw 106, it should be understood that in other embodiments, the robotic surgical device 104 may include or be used with one or more other surgical instruments, such as, for example, a surgical burr, a chisel, an impactor, a reamer, and other powered surgical tools. The robotic surgical device 104 may illustratively be embodied as the VELYS™ Robotic-Assisted Solution, commercially available from DePuy Synthes Products, Inc. of Warsaw, Indiana.

[0030] The surgical planning and assistance devices 102 and the robotic surgical devices 104 may be configured to send and receive data with each other and / or with other devices in the system 100 via a network 114. The network 114 may be embodied as any number of various wired and / or wireless networks. For example, the network 114 may be embodied as or otherwise include a wired or wireless local area network (LAN), a wired or wireless wide area network (WAN), a mobile network, and / or a publicly accessible global network such as the Internet. Accordingly, the network 114 may include any number of additional devices, such as additional computers, routers, stations, and switches, to facilitate communication between the devices in the system 100.

[0031] As shown in FIG. 1 , the system 100 further includes several alignment tools 108. As described further below, in use, the surgical planning and assistance device 102 may use an array of cameras 132 to track the location of the alignment tools 108 in space. For example, each alignment tool 108 may include several hydrophobic light reflectors arranged in a predetermined pattern visible to the camera 132. Illustratively, the alignment tools 108 include multiple arrays 110 each configured to be fixed to one of the patient's bones, the robotic surgical device 104, or the surgical tool 106. Illustratively, the alignment tool 108 also includes a pointer 112 configured to be temporarily positioned by the surgeon relative to the patient's anatomical landmarks (e.g., with an end of the pointer 112 in contact with those anatomical landmarks) while the pointer 112 is observed by the camera 132. Thus, the alignment tool 108 may be used for registering and tracking the patient's bony anatomy during an orthopedic surgical procedure. Although illustrated as including an alignment tool 108 suitable for optical tracking using a camera 132, it should be understood that in some embodiments, the system 100 may use electromagnetic tracking or other position tracking techniques to track the alignment tool 108.

[0032] Referring now to FIG. 2 , during use, the surgical planning and assistance device 102 may perform a method 200 for orthopedic surgical procedures using automatic bone model registration. The method 200 begins at block 202, where the device 102 receives a bone model generated based on one or more medical images. The bone model may be embodied as a three-dimensional computer model of the patient's bony anatomy, including one or more bone surfaces. For example, in some embodiments, the bone model may include a triangular mesh representing the bone surfaces. The bone model may be generated preoperatively based on one or more medical images. The medical images may include computerized tomography (CT) scan images, orthogonal x-ray images, magnetic resonance imaging (MRI), ultrasound, or images generated using other imaging techniques. As an illustrative example, a computing device or other modeling system (e.g., the surgical planning and assistance device 102 or another device) may perform an x-ray segmentation process to model the patient's bones based on input medical images. In the segmentation process, the device receives a set of x-ray images. The device accesses a bone library containing models or other measurements of many sample bones, generates a three-dimensional model based on the bone library, and then morphs (interpolates) the model to fit the specific geometry of the patient represented in the medical image.

[0033] At block 204, device 102 performs registration of the patient's bony anatomy. In an illustrative embodiment, block 204 involves the surgeon attaching bone array 110 to each of the patient's tibia and femur. The surgeon may use pointer 112 to touch various landmarks on the patient's bony anatomy. During this process, device 102 uses camera 132 to track the position of bone array 110 and pointer 112, thus registering the position of each landmark on the patient's bony anatomy. Thus, device 102 may capture multiple point locations within a surgical coordinate system relative to the patient's bone (e.g., relative to bone array 110 fixed to the patient's bone). In other embodiments, it is contemplated that device 102 may perform registration of the patient's bony anatomy using a non-contact registration tool, such as a laser or white light scanner, or an ultrasound device that uses light or sound waves to identify surfaces of the patient's anatomy. Although the remainder of this disclosure generally refers to the use of an alignment tool or pointer 112 configured to contact various locations on the patient's anatomy, embodiments according to the present disclosure may be used with non-contact alignment tools. As described further below, the device 102 may align the three-dimensional bone model to the same surgical coordinate system as the patient's bones by matching features of the bone model to corresponding landmarks on the patient's bones.

[0034] As part of bone registration, device 102 may perform an automated soft tissue thickness estimation process. During this process, the thickness of cartilage or other soft tissue coverings of the patient's bone may be taken into account during the registration process. The surgeon may verify the estimated soft tissue thickness by touching the soft tissue covering various portions of the patient's bony anatomy, for example, by using pointer 112, and verifying the reported position 112 relative to the bone model. In some embodiments, device 102 may perform a surgeon-initiated soft tissue thickness estimation process at block 206. One potential embodiment of a surgeon-initiated process is shown in FIGS. 3A-3C and described below. Additionally or alternatively, in some embodiments, device 102 may perform an automatic soft tissue thickness estimation process at block 208. One possible embodiment of an automatic process is shown in FIGS. 4A-4B and described below.

[0035] During bone alignment or at another time, device 102 may prompt the surgeon or other user to verify the implant size to be used in the orthopaedic surgical procedure. The implant size may be predetermined during pre-operative planning or may otherwise be set to a default value. After being prompted, the surgeon or other user may select a different implant size, which is stored by device 102 for further processing.

[0036] At block 210, in some embodiments, device 102 may perform a leg alignment registration to assess the balance of the patient's knee throughout the entire range of motion (e.g., in the case of a TKA surgical procedure). To perform the leg alignment registration, the surgeon may articulate the patient's knee through the range of motion while device 102 uses camera 132 to track the position of bone array 110, thus aligning the relative positions of the femur and tibia at multiple points within the range of motion. In some procedures, the surgeon may perform a soft tissue release, in which case the leg alignment registration may be repeated.

[0037] In block 212, the device 102 presents a surgical plan for review by the surgeon. The surgical plan may include information indicating the type, size, and position of one or more implants. For example, in a TKA surgical procedure, the surgical plan may include one or more of tibial or femoral resection height, femoral component rotation, femoral component flexion, femoral component anterior / posterior shift, tibial slope, and / or varus / valgus angle. The surgical plan may include similar information tailored for other surgical procedures. The surgical plan may be generated preoperatively or, in some embodiments, may be automatically and / or interactively generated and / or modified by the surgeon using the device 102.

[0038] Device 102 may use any input / output device or output modality to present the surgical plan. In some embodiments, device 102 may use display 130 to display numerical dimensions of resection heights, angles, position shifts, or other parameters of the surgical plan. In some embodiments, device 102 may use display 130 to graphically display the dimensions of the surgical plan. For example, device 102 may graphically render a three-dimensional model of the patient's bony anatomy, along with virtual prosthetic components positioned relative to the bony anatomy according to the surgical plan. In some embodiments, device 102 may use an augmented reality device and / or a virtual reality device (e.g., a head-mounted stereo display) to graphically display the surgical plan (including models of the patient's bony anatomy and / or virtual prosthetic components).

[0039] At block 214, the device 102 receives input regarding whether the surgeon desires to revise the surgical plan. For example, the surgeon may revise the surgical plan by modifying one or more planning values ​​of the surgical plan. As another example, the surgeon may adjust a particular planned resection height or angle. Alternatively, the surgeon may accept the surgical plan or otherwise indicate that no revision is necessary. If the device 102 is instructed to revise the surgical plan, the method 202 loops back to block 212, where the device 102 presents the revised surgical plan. If the device 102 determines not to revise the surgical plan, the method 200 proceeds to block 216.

[0040] At block 216, the device 102 controls the robotic surgical device 104 according to the surgical plan to assist the surgeon in performing the orthopaedic surgical procedure. The device 102 may transmit the surgical plan to the robotic surgical device 104 or otherwise cause the robotic surgical device 104 to operate according to the surgical plan. Illustratively, at block 218, the robotic surgical device 104 robotically constrains the surgical saw 106 to a predefined safety zone, such as a predefined resection plane. The safety zone may be identified in a bone model aligned with the patient's bony anatomy, as described above, or may be otherwise determined based thereon. For example, the robotic surgical device 104 may constrain the surgical saw 106 to a predefined safety zone defined by or relative to the bone model. The robotic surgical device 104 may locate this safety zone relative to the patient's anatomy by tracking the bone array 110 using the camera 132 of the device 102 in a surgical coordinate system, similar to the bone alignment process described above. After controlling the robotic surgical device 104, the method 200 is complete. The surgeon may continue the orthopaedic surgical procedure by, for example, attaching one or more trial components, one or more prostheses, or otherwise completing the orthopaedic surgical procedure.

[0041] 3A-3C , in use, the surgical planning and assistance device 102 may perform a method 300 for bone model registration with surgeon-directed soft tissue thickness estimation. The method 300 may be performed in connection with bone registration, as described above in connection with block 204 of FIG. 2 . The method 300 begins at block 302, where the device 102 captures one or more positions of the alignment tool 108 (e.g., pointer 112) when the surgeon contacts the alignment tool 108 at a designated location on the patient's bony anatomy. The device 102 may display or otherwise prompt the surgeon for the designated location. For example, the surgeon may contact the pointer 112 directly on the surface of the patient's bone at a particular bony landmark, or on the cartilage, meniscus, or other soft tissue overlying the patient's bone. Advantageously, the method 300 does not require the surgeon to drill through the cartilage, meniscus, or other soft tissue overlying the patient's bone, if present, to reach the underlying bone surface with the pointer 112. Alternatively, for such landmarks, the surgeon may touch the pointer 112 to the soft tissue surface (without directly touching the bone surface), and the device 102 will take into account the thickness of the soft tissue, as described below.

[0042] As an illustrative example, in the case of a TKA surgical procedure, the designated bony landmarks may include the tibial knee center, the medial tibial plateau, the lateral tibial plateau, the femoral knee center, the Whiteside line, the medial epicondyle of the femur, the lateral epicondyle of the femur, the medial distal femoral condyle, the lateral distal femoral condyle, the medial posterior femoral condyle, the lateral posterior femoral condyle, the anterior cortex of the femur, and / or other identified locations of the patient's knee joint. As another illustrative example, in the case of a TSA surgical procedure, the designated bony landmarks may include the humeral head, the biceps groove, the glenoid fossa, the acromion, and / or other identified locations of the patient's shoulder joint. As another illustrative example, in the case of a THA surgical procedure, the designated bony landmarks may include the femoral head, the acetabulum, and / or other identified locations of the patient's hip joint.

[0043] Each captured position of the registration tool 108 may be represented by coordinates in a surgical coordinate system relative to the patient's bone. For example, each captured position may be represented by a three-dimensional position relative to one or more of the arrays 110 affixed to the patient's bone. In some embodiments, the device 102 may capture a single point location of a particular landmark in block 304. For example, the device 102 may capture a particular point representing the location of the pointer 112 when positioned at the tibia knee center, the femoral knee center, or other predetermined location on the patient's bone (or the soft tissue overlying the patient's bone). In some embodiments, the device 102 may capture a point cloud of a surface that includes or is otherwise associated with the landmark in block 306. The point cloud may include many individual points captured as the surgeon moves the pointer 112 across the landmark and / or across the soft tissue overlying the landmark (or portion thereof). For example, device 102 may capture a point cloud representing the captured position of pointer 112 as it is moved across cartilage or other soft tissue overlying the humeral head, one or more tibial plateaus, one or more femoral condyles, and / or other bone surfaces.

[0044] At block 308, the device 102 receives a user estimate of soft tissue thickness for each bony anatomical structure location for which a registration position was captured, as described above in connection with block 302. The estimated soft tissue thickness may be provided by the surgeon or other user using the touchscreen display 130 and / or other user interface provided by the device 102. For example, the surgeon may provide an estimated soft tissue thickness in millimeters for cartilage or other soft tissue (if present) overlying a landmark (e.g., the humeral head, tibial plateau, femoral condyle, or other landmark). For landmarks that are not covered by soft tissue (or very little soft tissue), the user estimate of soft tissue thickness may be zero. Additionally or alternatively, in some embodiments, the estimated soft tissue thickness may be determined from one or more surgeon preferences, which may include a set of parameters defined by the surgeon before beginning the surgical procedure. In some embodiments, the estimated soft tissue thickness may be determined from a set of pre-defined default values.

[0045] At block 310, the device 102 determines whether additional locations remain for registration. As described above, the device 102 may capture registration locations for one or more predefined landmarks associated with a particular surgical procedure. If additional locations remain, the method 300 loops back to block 302. If additional locations do not remain for registration, the method 300 proceeds to block 312.

[0046] In block 312, the device 102 registers the bone model in the surgical coordinate system to the captured point locations using the soft tissue thickness estimates. The device 102 may register the bone model by determining a rigid body transformation of the bone model that minimizes the distance, error, or other cost function between the bone model and the captured point locations, taking into account the estimated soft tissue thickness associated with each captured point location. In block 314, the device 102 may determine the distance between each captured point location and its estimated soft tissue thickness extending outward from the bone model. As described above, each landmark or other location within the patient's bony anatomy may be associated with a different estimated soft tissue thickness (including zero). Thus, the distance between the point locations closest to or otherwise associated with each landmark or other location may be determined using the corresponding estimated soft tissue thickness. In some embodiments of block 314, the device 102 may register the bone model in the surgical coordinate system using both captured point locations with soft tissue thickness estimates greater than zero and captured point locations with soft tissue thickness estimates of zero.

[0047] In block 316, the device 102 may perform a Levenberg-Marquardt optimization process (or other optimization process, such as an iterative closest point algorithm) to align the bone model to the captured point locations. As part of this process, the device 102 may apply a rigid body transformation to the bone model, determine a distance measure between each captured point location and a corresponding point on the bone model extended by the associated estimated soft tissue thickness, and then iteratively adjust the transformation to minimize that distance measure. The device 102 may continue to optimize the alignment of the bone model until a local or global minimum is found or the process otherwise converges.

[0048] At block 318, the device 102 displays the registration results, including the registered bone model, the one or more captured point locations, and the estimated soft tissue thickness. These registration results may be displayed as numerical and / or graphical results. For example, in some embodiments, the device 102 may display a graphical representation of the bone model after it has been registered to the surgical coordinate system. The device 102 may display the soft tissue thickness as a three-dimensional overlay on the bone model or otherwise display the soft tissue thickness graphically, and the device 102 may display the registration locations as individual points, a point cloud, or other representation of the locations.

[0049] In block 320, the device 102 determines whether the surgeon requests to interactively confirm the alignment. If not, the method 300 proceeds to block 322, where the method 300 is complete. The surgical procedure may continue as described above in connection with FIG. 2. Referring again to block 320, if the surgeon requests to confirm the alignment, the method 300 proceeds to block 324, shown in FIG. 3C.

[0050] At block 324, the device 102 captures the position of the alignment tool 108 (e.g., the pointer 112) when the surgeon contacts the alignment tool 108 on the patient's bone or on soft tissue overlying a portion of the patient's bone. This capture process may be similar to the capture process performed during alignment as described above in connection with block 302. In some embodiments, the device 102 may capture and process the position of the alignment tool 108 in real time as the surgeon manipulates the tool 108. For example, the surgeon may contact the pointer 112 on the cartilage, meniscus, or other soft tissue overlying the patient's bone at a particular bony landmark. That bony landmark may have been one of the bony landmarks designated for alignment as described above in connection with block 302. Additionally, as described above, the captured position may be represented by coordinates in a surgical coordinate system relative to the patient's bone.

[0051] In some embodiments, block 324 (similar to block 302) may involve device 102 capturing locations at locations on the patient's bony anatomy that are known to have no or little soft tissue. For example, device 102 may capture locations on the patient's acromion on the scapula. Such captured locations at locations with no or little soft tissue may be useful in confirming proper alignment of the bone model.

[0052] In block 326, the device 102 determines the difference between the point location captured in block 324 and the corresponding registered position of the bone model incorporating the associated estimate of soft tissue thickness from block 308. For example, the device 102 may determine the distance in the surgical coordinate system between the point location captured in block 324 and a corresponding point that is either on the surface of the bone model (the estimated soft tissue thickness for that point was zero) or extends from the surface of the bone model by the estimated soft tissue thickness (the estimate was non-zero). The distance may be a minimum distance, an orthogonal distance, a distance in a predetermined direction, a height, or other distance measure between the captured point location and the point in the surgical coordinate system represented by the bone model extended by the estimated soft tissue thickness. In this example, a smaller difference indicates that the position of the pointer 112 better matches the registered position of the bone model for that location, taking into account any soft tissue. In other words, if the estimated soft tissue thickness matches the actual soft tissue thickness at that location, the difference between the point location captured in block 324 and the location of the corresponding point on the surface of the registered bone model plus the estimated soft tissue thickness will be zero or close to zero, indicating a good match between the registered bone model and the patient's actual bone.

[0053] In block 328, the device 102 displays the difference determined in block 326 to the surgeon and / or another user. Similar to the display of the alignment results described above in connection with block 318, the device 102 may display this difference numerically, graphically, or using any other technique. For example, the device 102 may display the distance determined in block 326 as a length in millimeters. As another example, the device 102 may graphically display the bone model along with one or more points, point clouds, surfaces, or other representations of the captured positions. In some embodiments, each point may be color-coded or otherwise marked to indicate the difference between the captured position and the corresponding aligned position of the bone model. For example, a point may be displayed in green if the difference is less than a first threshold (e.g., 0.7 mm, 1 mm, 2 mm, or a different threshold), in yellow if the difference is equal to or greater than the first threshold and less than a second threshold (e.g., 1.4 mm, 2 mm, 3 mm, or a different threshold), and in red if the difference is equal to or greater than the second threshold. The particular threshold used for color coding may be adjusted based on the estimated soft tissue thickness. Thus, the device 102 may provide a “green” indication to indicate that bone model alignment is adequate, even when the pointer 112 touches soft tissue at a relatively large distance (e.g., several millimeters) from the aligned bone model surface.

[0054] At block 330, the device 102 determines whether additional locations remain for verifying alignment. The device 102 may verify the alignment of multiple predefined landmarks associated with a particular surgical procedure, as described above. If additional locations remain, the method 300 loops back to block 324. If additional locations do not remain for verifying alignment, the method 300 proceeds to block 332.

[0055] At block 332, the device 102 determines whether the surgeon requests that the alignment be adjusted. If not, the method 300 proceeds to block 334, where the method 300 is complete. The surgical procedure may continue as described above in connection with FIG. 2. Referring again to block 332, if the surgeon requests that the alignment be adjusted, the method 300 proceeds to block 336.

[0056] At block 336, the device 102 receives updated user estimates of soft tissue thickness for one or more bony anatomical structure locations. Illustratively, the updated user estimates are determined by the surgeon based on the interactive registration verification process described above. Each estimated soft tissue thickness may be provided by the surgeon or other user using the touchscreen display 130 and / or other user interface provided by the device 102. For example, the surgeon may provide an estimated soft tissue thickness in millimeters for cartilage or other soft tissue overlying a landmark (e.g., the humeral head, tibial plateau, femoral condyle, or other landmark). After receiving the updated estimated soft tissue thickness, the method 300 loops back to block 312 shown in FIG. 3B , where the device 102 continues to register the bone model based on the updated point locations. Additionally or alternatively, although illustrated in Figures 3A-3C as updating the estimated soft tissue thickness after confirming the alignment of all of the bony landmarks, it should be understood that in some embodiments, the device 102 may receive an updated estimated soft tissue thickness after checking less than all of the bony landmarks and continue to update the alignment of the bone model as described above.

[0057] 4A and 4B , in use, the surgical planning and assistance device 102 may perform a method 400 for bone model registration with automatic soft tissue thickness estimation. The method 400 may be performed in connection with bone registration, as described above in connection with block 204 of FIG. 2 . The method 400 begins at block 402, where the device 102 captures one or more positions of the registration tool 108 (e.g., the pointer 112) when the surgeon contacts the registration tool 108 at a designated location on the patient's bony anatomy. The device 102 may display or otherwise prompt the surgeon for the designated location. For example, the surgeon may contact the pointer 112 directly on the surface of the patient's bone at a particular bony landmark, or on the cartilage, meniscus, or other soft tissue overlying the patient's bone. Advantageously, the method 400 does not require the surgeon to drill through the cartilage, meniscus, or other soft tissue overlying the patient's bone, if present, to reach the underlying bone surface with the pointer 112. Alternatively, for such landmarks, the surgeon may touch the pointer 112 to the soft tissue surface (without directly touching the bone surface), and the device 102 will take into account the thickness of the soft tissue, as described below.

[0058] As an illustrative example, in the case of a TKA surgical procedure, the designated bony landmarks may include the tibial knee center, the medial tibial plateau, the lateral tibial plateau, the femoral knee center, the Whiteside line, the medial epicondyle of the femur, the lateral epicondyle of the femur, the medial distal femoral condyle, the lateral distal femoral condyle, the medial posterior femoral condyle, the lateral posterior femoral condyle, the anterior cortex of the femur, and / or other identified locations of the patient's knee joint. As another illustrative example, in the case of a TSA surgical procedure, the designated bony landmarks may include the humeral head, the biceps groove, the glenoid fossa, the acromion, and / or other identified locations of the patient's shoulder joint. As another illustrative example, in the case of a THA surgical procedure, the designated bony landmarks may include the femoral head, the acetabulum, and / or other identified locations of the patient's hip joint.

[0059] Each captured position of the registration tool 108 may be represented by coordinates in a surgical coordinate system relative to the patient's bone. For example, each captured position may be represented by a three-dimensional position relative to one or more of the arrays 110 affixed to the patient's bone. In some embodiments, the device 102 may capture a single point location of a particular landmark in block 404. For example, the device 102 may capture a particular point representing the location of the pointer 112 when positioned at the tibia knee center, the femoral knee center, or other predetermined location on the patient's bone (or the soft tissue overlying the patient's bone). In some embodiments, the device 102 may capture a point cloud of a surface that includes or is otherwise associated with the landmark in block 406. The point cloud may include many individual points captured as the surgeon moves the pointer 112 across the landmark and / or across the soft tissue overlying the landmark (or portion thereof). For example, device 102 may capture a point cloud representing the captured position of pointer 112 as it is moved across cartilage or other soft tissue overlying the humeral head, one or more tibial plateaus, one or more femoral condyles, and / or other bone surfaces.

[0060] At block 408, the device 102 determines whether additional locations remain for registration. As described above, the device 102 may capture registration locations for one or more predefined landmarks associated with a particular surgical procedure. If additional locations remain, the method 400 loops back to block 402. If additional locations do not remain for registration, the method 400 proceeds to block 410.

[0061] In block 410, the device 102 registers the bone model in the surgical coordinate system to the captured point locations using an automatic estimate of soft tissue thickness. The device 102 may automatically associate an initial estimated soft tissue thickness (including zero) with each captured point location based on a standard anatomical model (which may be adjusted for patient characteristics, such as age, gender, height, and weight). As described above, the device 102 may register the bone model by determining a rigid body transformation of the bone model that minimizes the distance, error, or other cost function between the bone model and the captured point location, taking into account the estimated soft tissue thickness associated with each captured point. Thus, the distance between the point location closest to or otherwise associated with each landmark or other location may be determined using the corresponding estimated soft tissue thickness. For example, in some embodiments, the device 102 may perform a Levenberg-Marquardt optimization process (or other optimization process, such as an iterative closest point algorithm) to register the bone model to the captured point locations. In some embodiments of block 410, the device 102 may use both captured point locations with soft tissue thickness estimates greater than zero and captured point locations with soft tissue thickness estimates of zero to register the bone model within the surgical coordinate system.

[0062] At block 412, the device 102 automatically optimizes the estimated soft-tissue thickness values ​​to improve registration quality. As part of the registration process, the device 102 may apply a rigid-body transformation to the bone model and determine a distance estimate between each captured point location and the corresponding point on the bone model augmented by the associated estimated soft-tissue thickness. The device 102 may iteratively adjust the transformation and / or the estimated soft-tissue thickness values ​​at various locations to minimize the distance measure. The device 102 may use any suitable optimization algorithm or other technique to adjust the estimated soft-tissue thickness. In some embodiments, the device 102 may constrain the estimated soft-tissue thickness within one or more predefined boundaries at block 414. The predefined boundaries represent realistic or other possible values ​​of soft-tissue thickness, and each of these boundaries may be associated with a particular bony landmark or other location. For example, in one embodiment, the estimated cartilage thickness of the glenoid fossa may be constrained to a value between 0 mm and 2 mm. The estimated cartilage thickness for each anatomical location may be set to an initial value typical for that anatomical location and then optimized within predetermined boundaries.

[0063] At block 416, the device 102 displays the registration results, including the registered bone model, the one or more captured point locations, and the estimated soft tissue thickness. These registration results may be displayed as numerical and / or graphical results. For example, in some embodiments, the device 102 may display a graphical representation of the bone model after it has been registered to the surgical coordinate system. The device 102 may display the soft tissue thickness as a three-dimensional overlay on the bone model or otherwise display the soft tissue thickness graphically, and the device 102 may display the point locations as individual points, a point cloud, or other representation of the locations.

[0064] At block 418, the device 102 determines whether the surgeon requests to interactively confirm the alignment. If not, the method 400 proceeds to block 420, where the method 400 is complete. The surgical procedure may continue as described above in connection with FIG. 2. Referring again to block 418, if the surgeon requests to confirm the alignment, the method 400 proceeds to block 422, shown in FIG. 4B.

[0065] At block 422, the device 102 captures the position of the alignment tool 108 (e.g., the pointer 112) when the surgeon contacts the alignment tool 108 on the patient's bone or on soft tissue overlying a portion of the patient's bone. This capture process may be similar to the capture process performed during alignment as described above in connection with block 402. In some embodiments, the device 102 may capture and process the position of the alignment tool 108 in real time as the surgeon manipulates the tool 108. For example, the surgeon may contact the pointer 112 on cartilage, meniscus, or other soft tissue overlying the patient's bone at a particular bony landmark. That bony landmark may have been one of the bony landmarks designated for alignment as described above in connection with block 402. Additionally, as described above, the captured position may be represented by coordinates in a surgical coordinate system relative to the patient's bone.

[0066] In some embodiments, block 422 (similar to block 402) may involve device 102 capturing locations at locations on the patient's bony anatomy that are known to have no or little soft tissue. For example, device 102 may capture locations on the acromion of the patient's scapula. Such captured locations at locations with no or little soft tissue may be useful in confirming proper alignment of the bone model.

[0067] In block 424, the device 102 determines the difference between each point location captured in block 422 and the corresponding registered position of the bone model, thereby incorporating the associated estimate of soft tissue thickness (including any adjustments to that value made in block 412). For example, the device 102 may determine the distance in the surgical coordinate system between the point location captured in block 422 and a corresponding point that is either on the surface of the bone model (the estimated soft tissue thickness value for that point was zero) or extends from the surface of the bone model by the associated soft tissue thickness (the value was non-zero). The distance may be a minimum distance, an orthogonal distance, a distance in a predetermined direction, a height, or other distance measure between the captured point location and the point in the surgical coordinate system represented by the bone model extended by the estimated soft tissue thickness. In that example, a smaller difference indicates a better match between the position of the pointer 112 and the registered position of the bone model, taking into account the estimated soft tissue at that location. In other words, if the estimated soft tissue thickness matches the actual soft tissue thickness at that location, the difference between the point location captured in block 422 and the location of the corresponding point on the surface of the registered bone model plus the estimated soft tissue thickness will be zero or close to zero, indicating a good match between the registered bone model and the patient's actual bone.

[0068] At block 426, the device 102 displays the difference determined at block 424 to the surgeon and / or another user. The device 102 may display this difference numerically, graphically, or using any other technique. For example, the device 102 may display the distance determined at block 424 as a length in millimeters. As another example, the device 102 may graphically display a bone model along with one or more points, point clouds, surfaces, or other representations of the captured locations. In some embodiments, each point may be color-coded or otherwise marked to indicate the difference between the captured location and the corresponding registered location of the bone model. For example, a point may be displayed in green if the difference is less than a first threshold (e.g., 0.7 mm, 1 mm, 2 mm, or a different threshold), in yellow if the difference is equal to or greater than the first threshold and less than a second threshold (e.g., 1.4 mm, 2 mm, 3 mm, or a different threshold), and in red if the difference is equal to or greater than the second threshold. The particular threshold used for color coding may be adjusted based on estimated soft tissue thickness. Thus, device 102 may provide a "green" indication to indicate that bone model alignment is adequate, even when pointer 112 touches soft tissue at a relatively large distance (e.g., several millimeters) from the aligned bone model surface.

[0069] At block 428, the device 102 determines whether additional locations remain for verifying the alignment. The device 102 may verify the alignment of multiple predefined landmarks associated with a particular surgical procedure, as described above. If additional locations remain, the method 400 loops back to block 422. If additional locations do not remain for verifying the alignment, the method 400 proceeds to block 430, where the method 400 is completed. The surgical procedure may continue as described above in connection with FIG. 2. In some embodiments, the surgeon may decide to repeat the alignment, for example, if the interactive review of the results is unsatisfactory. In these embodiments, the surgeon may repeat the automatic alignment as described above in connection with FIGS. 4A and 4B and / or perform a surgeon-driven alignment as described above in connection with FIGS. 3A-3C.

[0070] Referring now to FIG. 5, an illustrative embodiment of a user interface 500 that may be provided by device 102 is shown. Specifically, interface 500 may be a graphical user interface for verifying bone model alignment, as described above in connection with FIGS. 3A-3C and / or 4A-4B. User interface 500 may be displayed in connection with aligning a humerus bone model, for example, during a TSA surgical procedure. User interface 500 includes graphical representations 502, 504 of the humerus bone model. The user interface further includes point representations 506, 508 corresponding to captured locations of pointer 112. Each of these point representations 506, 508 is displayed relative to the aligned bone models 502, 504 so that the surgeon may visually verify the alignment of the bone models. Additionally, each of point representations 506, 508 is patterned according to a legend 510 to indicate the distance between the captured location and the corresponding point on the aligned bone model. As described above, the particular threshold defined in the legend 510 can be adjusted depending on the estimated soft-tissue thickness. Thus, as shown in FIG. 5 , particular points 506, 508 displayed in the user interface 500 as being spaced apart from the surfaces of the bone models 502, 504 are shown as being accurately aligned based on the estimated soft-tissue thickness associated with each of those points. The user interface 500 further includes a label 514 that displays the distance between the captured point and the bone model as a numerical value, as well as a label 512 that displays the soft-tissue thickness as a numerical value. The device 102 can update one or more of those labels 512, 514, for example, in response to capturing additional positions of the pointer 112. Illustratively, the user interface 500 includes a navigation control 516 that can be used by the surgeon to select different bony landmarks or other locations to verify the alignment of the bone models.

[0071] Referring now to FIG. 6, an illustrative embodiment of a user interface 600 that may be provided by the device 102 is shown. Specifically, the interface 600 may be a graphical user interface for verifying bone model alignment, as described above in connection with FIGS. 3A-3C and / or 4A-4B. The user interface 600 may be displayed in connection with aligning bone models of the scapula and shoulder joint, for example, during a TSA surgical procedure. The user interface 600 includes graphical representations 602, 604 of bone models of the scapula. The user interface further includes point representations 606, 608 corresponding to captured positions of the pointer 112. Each of these point representations 606, 608 is displayed relative to the aligned bone models 602, 604 so that the surgeon can visually verify the alignment of the bone models. Additionally, each of the point representations 606, 608 is patterned according to a legend 610 to indicate the distance between the captured position and the corresponding point on the aligned bone models. As described above, the particular threshold defined in the legend 610 can be adjusted depending on the estimated soft-tissue thickness. Thus, as shown in FIG. 6 , particular points 606, 608 displayed in the user interface 600 as being spaced apart from the surfaces of the bone models 602, 604 are shown as being accurately aligned based on the estimated soft-tissue thickness associated with each of those points. The user interface 600 further includes a label 612 that displays the soft-tissue thickness as a numerical value, as well as a label 614 that displays the distance between the captured point and the bone model as a numerical value. The device 102 can update one or more of those labels 612, 614, for example, in response to capturing additional positions of the pointer 112. Illustratively, the user interface 600 includes a navigation control 616 that can be used by the surgeon to select different bony landmarks or other locations to verify the alignment of the bone models.

[0072] Referring now to FIG. 7 , an illustrative embodiment of a user interface 700 that may be provided by the device 102 is shown. Specifically, the interface 700 may be a graphical user interface for verifying bone model alignment, as described above in connection with FIGS. 3A-3C and / or 4A-4B . The user interface 700 may be displayed in connection with aligning a pelvic bone model, including the acetabulum, during a THA surgical procedure, for example. The user interface 700 includes a graphical representation 702 of the pelvic bone model. The user interface further includes point representations 704 corresponding to captured positions of the pointer 112. Each of these point representations 704 is displayed relative to the aligned bone model 702 so that the surgeon may visually verify the alignment of the bone models. Additionally, each of the point representations 704 is patterned according to a legend 706 to indicate the distance between the captured position and the corresponding point on the aligned bone model. As described above, the specific threshold defined in the legend 706 may be adjusted depending on the estimated soft tissue thickness. 7 , certain points 704 displayed in the user interface 700 as being spaced apart from the surface of the bone model 702 are shown as being accurately aligned based on the estimated soft tissue thickness associated with each of those points. The user interface 700 further includes labels 708 that display the soft tissue thickness as a numerical value, as well as labels 710 that display the distance between the captured points and the bone model as a numerical value. The device 102 may update one or more of those labels 708, 710, for example, in response to capturing additional positions of the pointer 112. Illustratively, the user interface 700 includes navigation controls 712 that can be used by the surgeon to select different bony landmarks or other locations to verify the alignment of the bone model.

[0073] Referring now to FIG. 8 , an illustrative embodiment of a user interface 800 that may be provided by the device 102 is shown. Specifically, the interface 800 may be a graphical user interface for verifying bone model alignment, as described above in connection with FIGS. 3A-3C and / or 4A-4B . The user interface 800 may be displayed in connection with aligning a bone model of a femur, including the femoral head, during a THA surgical procedure, for example. The user interface 800 includes a graphical representation 802 of the femur bone model. The user interface further includes point representations 804 corresponding to captured positions of the pointer 112. Each of these point representations 804 is displayed relative to the aligned bone model 802 so that the surgeon may visually verify the alignment of the bone models. Additionally, each of the point representations 804 is patterned according to a legend 806 to indicate the distance between the captured position and the corresponding point on the aligned bone model. As described above, the specific threshold defined in the legend 806 may be adjusted depending on the estimated soft tissue thickness. 8 , certain points 804 displayed in the user interface 800 as being spaced apart from the surface of the bone model 802 are shown as being accurately aligned based on the estimated soft tissue thickness associated with each of those points. The user interface 800 further includes labels 808 that display the soft tissue thickness as a numerical value, as well as labels 810 that display the distance between the captured points and the bone model as a numerical value. The device 102 may update one or more of those labels 808, 810, for example, in response to capturing additional positions of the pointer 112. Illustratively, the user interface 800 includes navigation controls 812 that can be used by the surgeon to select different bony landmarks or other locations to verify the alignment of the bone model.

[0074] Referring now to FIG. 9 , an illustrative embodiment of a user interface 900 that may be provided by device 102 is shown. Specifically, interface 900 may be a graphical user interface for verifying bone model alignment, as described above in connection with FIGS. 3A-3C and / or 4A-4B . User interface 900 may be displayed in connection with aligning a femoral bone model, including the distal end of the femur, during a TKA surgical procedure, for example. User interface 900 includes graphical representations 902, 904, 906 of the femoral bone model. The user interface further includes point representations 908, 910 corresponding to the captured position of pointer 112. Each of these point representations 908, 910 is displayed relative to the aligned bone models 902, 904, 906 so that the surgeon can visually verify the alignment of the bone models. Additionally, each of the point representations 908, 910 is patterned according to a legend 912 to indicate the distance between the captured location and the corresponding point on the aligned bone model. As described above, the specific threshold defined in the legend 912 can be adjusted depending on the estimated soft tissue thickness. Thus, as shown in FIG. 9 , specific points 908, 910 displayed in the user interface 900 as being spaced apart from the surface of the bone models 902, 904, 906 are shown as being accurately aligned based on the estimated soft tissue thickness associated with each of those points. The user interface 900 further includes a label 916 that displays the distance between the captured point and the bone model as a numeric value, as well as a label 914 that displays the soft tissue thickness as a numeric value. The device 102 may update one or more of the labels 914, 916, for example, in response to capturing additional positions of the pointer 112. Illustratively, the user interface 900 includes a navigation control 918 that can be used by the surgeon to select different bony landmarks or other locations to verify the alignment of the bone models.

[0075] Referring now to FIG. 10 , an illustrative embodiment of a user interface 1000 that may be provided by the device 102 is shown. Specifically, the interface 1000 may be a graphical user interface for verifying bone model alignment, as described above in connection with FIGS. 3A-3C and / or 4A-4B . The user interface 1000 may be displayed in connection with the alignment of a tibia bone model, including the proximal end of the tibia, during a TKA surgical procedure, for example. The user interface 1000 includes a graphical representation 1002 of the tibia bone model. The user interface further includes point representations 1004 corresponding to positions of the pointer 112 captured by the surgeon while verifying the bone model alignment. Each of these point representations 1004 is displayed relative to the aligned bone model 1002 so that the surgeon may visually verify the bone model alignment. Additionally, each of the point representations 1004 is patterned according to a legend 1006 to indicate the distance between the captured position and the corresponding point on the aligned bone model. As described above, the particular threshold defined in the legend 1006 can be adjusted depending on the estimated soft-tissue thickness. Thus, as shown in FIG. 10 , particular points 1004 displayed in the user interface 1000 as being spaced apart from the surface of the bone model 1002 are shown as being accurately aligned based on the estimated soft-tissue thickness associated with each of those points. The user interface 1000 further includes a label 1010 that displays the distance between the captured point and the bone model as a numerical value, as well as a label 1008 that displays the soft-tissue thickness as a numerical value. The device 102 can update one or more of those labels 1008, 1010, for example, in response to capturing additional positions of the pointer 112. Illustratively, the user interface 1000 includes a navigation control 1012 that can be used by the surgeon to select different bony landmarks or other locations to verify the alignment of the bone model.

[0076] While the present disclosure has been illustrated and described in detail in the drawings and foregoing description, it is understood that such illustration and description is merely exemplary in nature and is not to be regarded as restrictive, and that merely illustrative embodiments have been shown and described, and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.

[0077] There are multiple advantages of the present disclosure that derive from the various features of the devices, systems, and methods described herein. It should be noted that alternative embodiments of the devices, systems, and methods of the present disclosure may not include all of the features described, but will benefit from at least some of the advantages of such features. Those skilled in the art may readily devise their own implementations of the devices, systems, and methods that incorporate one or more of the features of the present invention and are within the spirit and scope of the present disclosure.

[0078] [Embodiment] (1) A bone model alignment method, comprising: defining, by a computing device, a surgical coordinate system relative to a bone of the patient; capturing, with the computing device, a plurality of point locations within the surgical coordinate system, each of the plurality of point locations being associated with an anatomical landmark of the patient's bone, the plurality of point locations including a first point location representing a location on a soft tissue surface overlying a portion of the patient's bone; identifying, by the computing device, an estimated soft tissue thickness value for each of the plurality of point locations; and registering, by the computing device, a three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness value. (2) The method of embodiment 1, wherein capturing the multiple point positions includes tracking the location of an alignment tool having a pointer using a camera array coupled to the computing device, and the pointer of the alignment tool directly contacts the soft tissue surface but does not directly contact the patient's bone while the first point position is being captured. (3) The method of embodiment 2, wherein the plurality of point positions further includes a second point position captured while the pointer of the alignment tool is in direct contact with the patient's bone. (4) identifying an estimated soft tissue thickness value for each of the plurality of point locations includes: identifying the estimated soft tissue thickness value for the first point location as a number greater than zero; and identifying the estimated soft tissue thickness value for the second point location as zero. (5) The method of embodiment 2, wherein capturing the plurality of point locations includes moving the pointer of the alignment tool along the surface of the patient's bone or along the soft tissue surface to capture a cloud of points associated with anatomical landmarks.

[0079] (6) The method of embodiment 1, wherein identifying an estimated soft tissue thickness value for each of the plurality of point locations includes receiving one or more estimates of soft tissue thickness from a surgeon during an orthopedic surgical procedure. (7) The method of embodiment 1, wherein identifying an estimated soft tissue thickness value for each of the plurality of point locations includes retrieving one or more initial estimated soft tissue thickness values ​​associated with the plurality of point locations from a memory device. (8) receiving, by the computing device, an updated estimated soft tissue thickness value for at least one of the plurality of point locations; and 2. The method of claim 1, further comprising: realigning, by the computing device, the three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness values, including the at least one updated estimated soft tissue thickness value. (9) The method of embodiment 1, wherein registering the three-dimensional model includes, for each of the plurality of point locations, determining a distance between the point location and a corresponding point from the three-dimensional model expanded by the estimated soft tissue thickness value associated with the point location to determine a set of distances associated with the transformation of the three-dimensional model. (10) The method of embodiment 9, wherein aligning the three-dimensional models further comprises optimizing the set of distances by iteratively adjusting the transformation of the three-dimensional models to improve the quality of the alignment of the three-dimensional models.

[0080] (11) The method of embodiment 10, wherein registering the three-dimensional model further includes optimizing the set of distances by iteratively adjusting the estimated soft tissue thickness values ​​associated with one or more of the plurality of point locations to improve the quality of registration of the three-dimensional model. (12) The method of embodiment 1, further comprising, after registering the three-dimensional model, displaying, by the computing device, a representation of the three-dimensional model in the surgical coordinate system. (13) The method of claim 12, further comprising displaying, by the computing device, the plurality of point locations relative to the displayed representation of the three-dimensional model. (14) A method as described in embodiment 13, wherein displaying the plurality of point positions on the displayed representation of the three-dimensional model includes color-coding each of the plurality of point positions according to the distance between each point position and a corresponding point from the three-dimensional model extended by the estimated soft tissue thickness value associated with that point position. (15) After aligning the three-dimensional models, capturing, with the computing device, a verification point location while a pointer of an alignment tool is in contact with the soft tissue surface overlying the portion of the patient's bone; displaying, by the computing device, the verification point locations relative to the displayed representation of the three-dimensional model; 13. The method of claim 12, further comprising displaying, by the computing device, a difference between the verification point location and a corresponding point from the three-dimensional model expanded by the estimated soft tissue thickness value associated with the corresponding point.

[0081] (16) Displaying the difference between the verification point location and the corresponding point from the three-dimensional model expanded by the estimated soft tissue thickness value associated with the corresponding point includes: If the difference is less than a first threshold, displaying the verification point location using a first color; 16. The method of claim 15, further comprising: if the difference is greater than the first threshold, displaying the confirmation point location using a second color different from the first color. (17) The method of embodiment 1, further comprising creating, by the computing device, the three-dimensional model based on one or more preoperative medical images. (18) The method of embodiment 1, further comprising, after registering the three-dimensional model, controlling, by the computing device, a robotic surgical device within the surgical coordinate system based on the three-dimensional model. (19) An orthopedic surgery system, comprising: a computing device, the computing device comprising: defining a surgical coordinate system relative to the patient's bones; capturing a plurality of point locations within the surgical coordinate system, each of the plurality of point locations being associated with an anatomical landmark of the patient's bone, the plurality of point locations including a first point location representing a location on a soft tissue surface overlying a portion of the patient's bone; identifying an estimated soft tissue thickness value for each of the plurality of point locations; and registering a three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness value. (20) a registration tool having pointers configured to contact various locations on the patient's anatomy; a camera array coupled to the computing device, The system of embodiment 20, wherein the computing device is configured to capture the multiple point positions by tracking the location of the alignment tool using the camera array, and the computing device is configured to capture the first point position while the pointer of the alignment tool is in direct contact with the soft tissue surface but not in direct contact with the patient's bone.

Claims

1. 1. An orthopedic surgical system comprising: a computing device, the computing device comprising: defining a surgical coordinate system relative to the patient's bones; capturing a plurality of point locations within the surgical coordinate system, each of the plurality of point locations being associated with an anatomical landmark of the patient's bone, the plurality of point locations including a first point location representing a location on a soft tissue surface overlying a portion of the patient's bone; identifying an estimated soft tissue thickness value for each of the plurality of point locations; and registering a three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness value.

2. an alignment tool having pointers configured to contact various locations on the patient's anatomy; a camera array coupled to the computing device, 2. The system of claim 1, wherein the computing device is configured to capture the plurality of point locations by tracking a location of the alignment tool using the camera array, and wherein the computing device is configured to capture the first point location while the pointer of the alignment tool is in direct contact with the soft tissue surface but not in direct contact with the patient's bone.

3. A bone model registration method, comprising: defining, by a computing device, a surgical coordinate system relative to a bone of the patient; capturing, with the computing device, a plurality of point locations within the surgical coordinate system, each of the plurality of point locations being associated with an anatomical landmark of the patient's bone, the plurality of point locations including a first point location representing a location on a soft tissue surface overlying a portion of the patient's bone; identifying, by the computing device, an estimated soft tissue thickness value for each of the plurality of point locations; and registering, by the computing device, a three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness value.

4. 4. The method of claim 3, wherein capturing the plurality of point locations includes tracking the location of a registration tool having a pointer using a camera array coupled to the computing device, the pointer of the registration tool directly contacting the soft tissue surface but not directly contacting the patient's bone while the first point locations are being captured.

5. The method of claim 4 , wherein the plurality of point locations further includes a second point location captured while the pointer of the registration tool is in direct contact with the patient's bone.

6. Identifying an estimated soft tissue thickness value for each of the plurality of point locations includes: identifying the estimated soft tissue thickness value for the first point location as a number greater than zero; and identifying the estimated soft tissue thickness value for the second point location as zero.

7. 5. The method of claim 4, wherein capturing the plurality of point locations comprises moving the pointer of the registration tool along a surface of the patient's bone or along the soft tissue surface to capture a cloud of points associated with anatomical landmarks.

8. 4. The method of claim 3, wherein identifying an estimated soft tissue thickness value for each of the plurality of point locations comprises receiving one or more estimates of soft tissue thickness from a surgeon during an orthopedic surgical procedure.

9. 4. The method of claim 3, wherein identifying an estimated soft tissue thickness value for each of the plurality of point locations includes retrieving one or more initial estimated soft tissue thickness values ​​associated with the plurality of point locations from a memory device.

10. receiving, by the computing device, an updated estimated soft tissue thickness value for at least one of the plurality of point locations; 4. The method of claim 3, further comprising: realigning, by the computing device, the three-dimensional model of the patient's bone within the surgical coordinate system based on the plurality of point locations and the estimated soft tissue thickness values, including the at least one updated estimated soft tissue thickness value.

11. 4. The method of claim 3, wherein registering the three-dimensional model includes determining, for each of the plurality of point locations, a distance between the point location and a corresponding point from the three-dimensional model expanded by the estimated soft tissue thickness value associated with the point location to determine a set of distances associated with a transformation of the three-dimensional model.

12. 12. The method of claim 11 , wherein registering the three-dimensional models further comprises optimizing the set of distances by iteratively adjusting the transformations of the three-dimensional models to improve a quality of registration of the three-dimensional models.

13. 13. The method of claim 12, wherein registering the three-dimensional model further comprises optimizing the set of distances by iteratively adjusting the estimated soft tissue thickness values ​​associated with one or more of the plurality of point locations to improve a quality of registration of the three-dimensional model.

14. The method of claim 3 , further comprising, after registering the three-dimensional model, displaying, by the computing device, a representation of the three-dimensional model in the surgical coordinate system.

15. The method of claim 14 , further comprising displaying, by the computing device, the plurality of point locations relative to the displayed representation of the three-dimensional model.

16. 16. The method of claim 15, wherein displaying the plurality of point locations on the displayed representation of the three-dimensional model includes color-coding each of the plurality of point locations according to a distance between each point location and a corresponding point from the three-dimensional model extended by the estimated soft tissue thickness value associated with that point location.

17. After aligning the three-dimensional models, capturing, with the computing device, a verification point location while a pointer of an alignment tool is in contact with the soft tissue surface overlying the portion of the patient's bone; displaying, by the computing device, the verification point locations relative to the displayed representation of the three-dimensional model; 15. The method of claim 14, further comprising displaying, by the computing device, a difference between the verification point location and a corresponding point from the three-dimensional model expanded by the estimated soft tissue thickness value associated with the corresponding point.

18. Displaying the difference between the verification point location and the corresponding point from the three-dimensional model expanded by the estimated soft tissue thickness value associated with the corresponding point includes: If the difference is less than a first threshold, displaying the verification point location using a first color; and if the difference is greater than the first threshold, displaying the verification point location using a second color different from the first color.

19. The method of claim 3 , further comprising creating, by the computing device, the three-dimensional model based on one or more pre-operative medical images.

20. The method of claim 3 , further comprising, after registering the three-dimensional model, controlling, by the computing device, a robotic surgical device within the surgical coordinate system based on the three-dimensional model.

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