System for robotic-assisted revision procedures

Abstract

A system and method for performing revision surgery using a robotic-assisted surgical system is provided. A method for performing revision surgery includes determining information about an interface region between an implant component and bone, and generating a planned virtual boundary within a representation of the implant and bone that is associated with a portion of the interface region to be removed based at least in part on the information about the interface region. The method further includes tracking movement of a cutting tool in physical space such that movement of the cutting tool correlates with movement of a virtual tool, and providing constraints to the cutting tool while it removes the portion of the interface region. The constraints are based on a relationship between the virtual tool and the planned virtual boundary. The portion of the interface region is removed to remove the implant component from the bone.

Description

[Technical Field]

[0001] Cross-reference to related patent applications This application claims priority to and benefit of U.S. Provisional Patent Application No. 62 / 363,037, filed July 15, 2016, which is incorporated herein by reference in its entirety. [Background technology]

[0002] background The present disclosure relates to robotic-assisted orthopaedic surgery, and more particularly to robotic-assisted revision surgery.

[0003] Currently, surgeons perform revision surgeries, such as revision knee and hip replacement procedures, manually. This manual procedure is not always precise, is difficult to perform, and can result in more bone loss than desired, reducing bone strength and integrity. Significant bone loss can occur due to limited access and imprecise cutting, implant removal, and implant cementation. During the procedure, surgeons may use chisels and microsaws to manually cut the implant. To preserve bone, surgeons must perform this approach very slowly. However, the duration of anesthesia can make surgical timing critical for patients. Additionally, significant training is required to perform such procedures. Summary of the Invention

[0004] In one exemplary embodiment, there is a method for performing revision surgery using a robotic-assisted surgical system. The method includes determining, by a processing circuit associated with a computer, information regarding an interface region between an implant component and a bone into which the implant component is implanted. The method further includes generating, by the processing circuit, a planned virtual boundary within a representation of the implant component and bone that is based at least in part on the information regarding the interface region and that is associated with a portion of the interface region to be removed. The method further includes monitoring, by a navigation system associated with the computer, movement of the cutting tool in physical space such that movement of the cutting tool correlates with movement of a virtual tool; and providing constraints to the cutting tool based on the relationship between the virtual tool and the planned virtual boundary while the cutting tool removes the portion of the interface region. The portion of the interface region is removed to remove the implant component from the bone.

[0005] In some embodiments, determining information regarding the interface region includes receiving an image of the bone and an implant component implanted therein. In some embodiments, the image is acquired in connection with a primary procedure of implanting the implant component into the bone. In some embodiments, the image is received by at least one imaging modality from the group consisting of CT, X-ray, fluoroscopy, MRI, ultrasound, a video camera, and a monitored marker. In some embodiments, determining information regarding the interface region includes digitizing the interface region with a monitored probe.

[0006] In some embodiments, the method further includes receiving input to adjust the virtual boundary relative to the representation of the implant and bone. In some embodiments, the virtual boundary is a haptic boundary, and providing the constraint includes providing haptic feedback to the cutting tool. In some embodiments, the virtual boundary is an autonomous control boundary, and providing the constraint includes autonomously controlling the surgical tool to stay within the control boundary. In some embodiments, the cutting tool is one or more tools from the group consisting of, but not limited to, a flat saw, a curved saw, a laser, a water jet, an ultrasonic vibration, and a burr.

[0007] In some embodiments, the method further includes determining, by a processing circuit, information regarding at least one of the size, amount, and location of a bone defect near the interface requiring augmentation. In some embodiments, the information is determined preoperatively. In some embodiments, the information is determined by digitizing the bone defect with a monitored probe.

[0008] In some embodiments, the method further includes acquiring an image of the bone using a video camera after the implant component has been removed, and generating a bone model of the bone based on the image for planning replacement of the implant component.

[0009] In some embodiments, the method further includes determining a desired pose of a replacement implant component for implantation into the bone. In some embodiments, the method further includes determining, by the processing circuitry, a second planning virtual boundary within the representation of the bone, the second planning virtual boundary representing one or more cuts in the bone to prepare the bone to receive the replacement implant. In some embodiments, the method further includes providing a constraint to the cutting tool based on a relationship between the virtual tool and the second planning virtual boundary while the cutting tool makes one or more cuts to prepare the bone.

[0010] In another exemplary aspect, there is a system for performing revision surgery. The system includes a robotic system including an articulating arm and a surgical tool coupled to the articulating arm; a navigation system configured to characterize movement of at least one of the articulating arm, the surgical tool, and a portion of a patient's anatomy to be revised; and a processor operatively coupled to the robotic system and the navigation system. The processor is configured to: determine information about an interface region between an implant component and a bone in which the implant component is implanted; generate a planned virtual boundary based at least in part on the information about the interface region and associated with a portion of the interface region to be removed based on a representation of the implant component and the bone; monitor movement of the cutting tool in physical space using the navigation system such that movement of the cutting tool correlates with movement of a virtual tool; and provide constraints to the cutting tool based on the relationship between the virtual tool and the planned virtual boundary while the cutting tool removes the portion of the interface region.

[0011] In some embodiments, the system further includes an imaging system operatively linked to the processor for determining information regarding the interface region, the imaging system including at least one imaging modality from the group consisting of CT, X-ray, fluoroscopy, MRI, ultrasound, a video camera, and a monitored marker. In some embodiments, the system further includes a monitored probe for digitizing the interface region.

[0012] In some embodiments, the surgical tool coupled to the articulating arm includes an end effector including at least one flexible bend element capable of movement in two degrees of freedom, the end effector including a distal end, a proximal end, and an internal channel; a shaft coupled to the proximal end of the flexible bend element and configured to securely secure the end effector to a surgical system; and a motor housed within the shaft and coupled to the cutting tool to provide power to the cutting tool. A cutting element is coupled to the distal end of the flexible bend element.

[0013] In one embodiment, a robotic system is used to assist in revision knee and hip replacement procedures. The robotic system may include a navigation system that aligns actual bones with pre-scanned CT images and precisely guides the robotic arm to navigate through the patient's anatomical space. The robotic system may have a haptic function that allows the user to shape a haptic volume based on the patient's anatomy to protect critical bony structures and soft tissues (ligaments, nerves, veins, etc.). The system may further include a flexible end effector with multiple degrees of freedom and the ability to bend 90 degrees in any direction, allowing a cutting tool attached to the flexible arm to access small areas for cutting bone implants. The system may also have a large database that stores patient bone and implant models, as well as planning history from primary knee or hip procedures, available for revision cases.

[0014] In another aspect, a robotic system using previous / primary information of the patient's knee and hip may assist in revision cases by using previous / primary implant models of the patient's knee and hip to create a revision haptic boundary to haptically guide the revision procedure; using previous / primary bone models of the patient's knee and hip to register the bone to robot coordinates, eliminating the need for the patient to take separate CT images for the revision case; and using previous / primary planning information of the patient's knee and hip to identify the relative position between the bone and implant in the revision case, eliminating relative motion between the bone and implant and using the implant surfaces to register the bone to robot coordinates.

[0015] In some embodiments, the robotic system creates a customized revision haptic boundary to prevent overcutting of the bone and minimize bone loss during the revision procedure.

[0016] In some embodiments, the robotic system precisely creates a revision haptic boundary around the primary implant based on a primary knee and hip implant model to constrain the cutting tool and minimize over-cutting of the bone. In some embodiments, one of the following methods is used to register the implant and bone to the primary CT image of the knee and hip during the revision surgery: a monitorable probe to digitize the implant surface and then register the bone to the primary CT image; taking several fluoroscopic images; and / or attaching a camera or optical sensor to the robot to scan the implant surface and then register it to the primary CT bone model. In some embodiments, the robotic system includes a sophisticated flexible end-effector system that has multiple degrees of freedom and is bendable in all directions, allowing the robot to cut bone in limited access spaces, and is equipped with a high-speed rotating burr for cutting the bone. In some embodiments, a video camera or ultrasound device is used to create an initial model of the bone or implant and / or to register the bone to the bone model. [The present invention 1001] The following stages: determining, by processing circuitry associated with a computer, information regarding an interface region between the implant component and the bone into which the implant component is implanted; generating, by the processing circuitry, a planned virtual boundary within the representation of the implant component and the bone, the planned virtual boundary relating to a portion of the interface region to be removed and based at least in part on the information regarding the interface region; monitoring movement of the cutting tool in physical space with a navigation system associated with the computer such that movement of the cutting tool correlates with movement of a virtual tool; providing a constraint to the cutting tool based on a relationship between the virtual tool and the planned virtual boundary while the cutting tool removes the portion of the interface region; and removing the portion of the interface region to remove the implant component from the bone. 1. A method for performing revision surgery using a robotic-assisted surgical system, comprising: [The present invention 1002] 10. The method of claim 10, wherein the step of determining information about the interface region includes generating a model of the bone and the implant component implanted therein. [The present invention 1003] The method of the present invention 1002, wherein the bone model is created from images acquired in connection with a primary procedure of implanting an implant component into the bone. [The present invention 1004] The method of the present invention 1002, wherein the model is generated by at least one modality from the group consisting of CT, X-ray, fluoroscopy, MRI, ultrasound, video camera, and monitored markers. [The present invention 1005] 10. The method of claim 10, wherein the step of determining information about the interface region includes digitizing the interface region with the probe being monitored. [The present invention 1006] The method of claim 1001 further comprising receiving input for adjusting the virtual boundary relative to the implant and bone representation. [The present invention 1007] 10. The method of claim 10, wherein the virtual boundary is a haptic boundary and the step of providing a constraint includes providing haptic feedback to the cutting tool. [The present invention 1008] 1001. The method of claim 1001, wherein the virtual boundary is an autonomous control boundary, and the step of providing a constraint includes autonomously controlling a cutting tool to stay within the control boundary. [The present invention 1009] The method of claim 1001, wherein the cutting tool is one or more tools from the group consisting of a flat saw, a curved saw, and a burr. [The present invention 1010] The method of claim 1001, further comprising determining by a processing circuit information regarding at least one of the size, amount, and location of a bone defect near the interface requiring augmentation material. [The present invention 1011] The method of claim 1010, wherein said information is determined preoperatively. [The present invention 1012] The method of claim 1010, wherein said information is determined by digitizing the bone defect with a monitored probe. [The present invention 1013] capturing an image of the bone using a video camera after the implant components have been removed; and generating a bone model of the bone based on the image to plan replacement of the implant component. The method of the present invention 1001 further comprising: [The present invention 1014] 1002. A method according to claim 1001, further comprising the step of determining a desired pose of a replacement implant component for implantation into said bone. [The present invention 1015] The method of the present invention 1014 further comprising a step of determining, by a processing circuit, a second planning virtual boundary within the representation of the bone, the second planning virtual boundary representing one or more cuts in the bone to prepare the bone to receive a replacement implant. [The present invention 1016] The method of the present invention 1015 further includes a step of providing constraints to the cutting tool based on a relationship between the virtual tool and a second planning virtual boundary while the cutting tool performs one or more cuts to prepare bone. [The present invention 1017] a robotic system including an articulating arm and a surgical tool coupled to the articulating arm; a navigation system configured to characterize movement of at least one of the articulating arm, the surgical tool, and a revision portion of the patient's anatomy; a processor operatively coupled to the robotic system and the navigation system, determining information regarding an interface region between the implant component and the bone into which the implant component is implanted; generating a planning virtual boundary within the representation of the implant component and the bone based at least in part on information regarding the interface region and related to the portion of the interface region to be removed; monitoring movement of the cutting tool in physical space with the navigation system such that movement of the cutting tool correlates with movement of a virtual tool; and providing constraints to the cutting tool based on a relationship between the virtual tool and the planned virtual boundary while the cutting tool removes the portion of the interface region; The processor and 1. A system for performing revision surgery, comprising: [The present invention 1018] an imaging system operatively coupled to the processor for determining information regarding the interface region, the imaging system including at least one imaging modality from the group consisting of CT, X-ray, fluoroscopy, MRI, ultrasound, a video camera, and a monitored marker; The system of the present invention 1017 further includes: [The present invention 1019] The system of the present invention 1017 further comprising a monitored probe for digitizing the interface region. [The present invention 1020] a surgical tool coupled to the articulating arm, the surgical tool including an end effector; The end effector at least one flexible bend element capable of movement in two degrees of freedom, the flexible bend element including a distal end, a proximal end, and an internal channel; a shaft coupled to the proximal end of the flexible bend element and configured to securely secure the end effector to a surgical system; a motor housed within the shaft and coupled to the cutting tool for providing power to the cutting tool; Including, a cutting element coupled to the distal end of the flexible bend element; The system of the present invention 1017. [Brief explanation of the drawings]

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects which, together with the description, serve to explain the principles and features of the present disclosure.

[0018] [Figure 1] FIG. 1 is a perspective view of one embodiment of a surgical system, according to an exemplary embodiment. [Figure 2] FIG. 1 is a block diagram of a computing system according to an example embodiment. [Figure 3] 3A-3B are diagrams of x-ray images showing a femur, a tibia, a femoral implant, and a tibial implant, according to an exemplary embodiment. [Figure 4] FIG. 10 is a diagram of bone and implant models shown on the user interface during a primary partial knee replacement procedure. [Figure 5A] FIG. 2 is a diagram of a flexible end effector for use with the surgical system of FIG. 1 according to an exemplary embodiment. [Figure 5B] FIG. 5B is a diagram of the flexible end effector of FIG. 5A according to an exemplary embodiment. [Figure 5C] FIG. 5B is a close-up view of a flexible portion of the flexible end effector of FIG. 5A, according to an exemplary embodiment. [Figure 6A] 1A-1C illustrate various views of a femur, a femoral implant, and an end effector according to an exemplary embodiment. [Figure 6B] 1A-1C illustrate various views of a femur, a femoral implant, and an end effector according to an exemplary embodiment. [Figure 6C] 1A-1C illustrate various views of a femur, a femoral implant, and an end effector according to an exemplary embodiment. [Figure 7] 7A and 7B show the femoral implant and femur after non-robotic or manual removal. [Figure 8] 1 is a flowchart of a method for performing revision surgery, according to an example embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Detailed Description While the drawings set forth illustrative embodiments of the invention in detail, before referring to the drawings, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the drawings. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.

[0020] The present disclosure introduces a robotic-assisted approach to support revision procedures in joints such as knees or hips by enabling precise removal of primary implants with minimal bone loss while reducing the time required for primary implant removal. Minimized bone loss increases the number of revision procedures that can be performed within an individual patient's lifetime.

[0021] Although this disclosure refers to knee and hip joints and revision knee and hip joint replacement procedures, the systems and methods disclosed herein are equally applicable to other orthopedic revision procedures for other bones and joints, including, but not limited to, the shoulder, wrist, ankle, spine, etc.

[0022] The robotic-assisted surgical system of the present disclosure is designed to assist in revision procedures to minimize the amount of bone removed and / or bone damage. The robotic-assisted surgical system of the present disclosure is also designed to shorten the long learning curve for surgeons to perform revision procedures. The robotic-assisted surgical system of the present disclosure may help reduce the time to perform revision procedures, and may result in less bone "trauma" as a result of using a robotic system, potentially resulting in better bone healing. In addition, the present disclosure addresses one of the major problems with previously used systems: visibility of the progression of interface breakdown. In certain embodiments, the robotic system of the present disclosure may provide the user with a plan for complete removal of the interface portion and then assist the user in executing the plan, providing feedback during the removal process.

[0023] Exemplary Robotic System Various features of robotic-assisted surgical systems and methods according to the present disclosure are described in more detail below. FIG. 1 illustrates a schematic diagram of an exemplary computer-assisted surgery (CAS) system 100 in which processes and features associated with certain disclosed embodiments may be implemented. Surgical system 100 may be configured to perform a wide variety of orthopedic surgical procedures, such as, for example, knee revision procedures. Surgical system 100 includes a monitoring system 101, a computing system 102, one or more display devices 103 a, 103 b, and a robotic system 104. It should be understood that system 100 and the methods and processes described herein may be applicable to many different types of joint revision procedures. While certain disclosed embodiments may be described with respect to knee revision procedures, the concepts and methods described herein may be applicable to other types of orthopedic surgical procedures, such as hip revision procedures, shoulder revision procedures, and other types of orthopedic surgical procedures. Additionally, surgical system 100 may include additional or fewer elements than those described herein (eg, a surgical table, etc.) to aid in surgery.

[0024] The robotic system 104 may be used by a surgeon in an interactive manner to perform a surgical procedure, such as a revision procedure, on a patient. As shown in FIG. 1 , the robotic system 104 includes a base 105, an articulating arm 106, a force sensing system (not shown), and a controller (not shown). A surgical tool 110 (e.g., an end effector having an actuating member such as a saw, a reamer, or a burr) may be coupled to the articulating arm 106. A surgeon may manipulate the surgical tool 110 by grasping and manually moving the articulating arm 106 and / or the surgical tool 110.

[0025] The haptic system and controller are configured to provide the surgeon with cut containment guidance via control or guidance during manipulation of the surgical tool. The haptic system is configured to provide at least some force to the surgical tool via the articulating arm 106, and the controller is programmed to generate control signals for controlling the haptic system. In one embodiment, the haptic system includes an actuator and a back-drivable transmission that provides haptic (or force) feedback to constrain or inhibit the surgeon from manually moving the surgical tool beyond a haptic boundary predefined by a haptic object, as described, for example, in U.S. Pat. No. 8,010,180 and / or U.S. Patent Application No. 12 / 654,519, filed December 22, 2009 (U.S. Patent Application Publication No. 2010 / 0170362), each of which is incorporated herein by reference in its entirety. The haptic system and controller may be housed within the robotic system 104. In some embodiments, cutting restraint or guidance is provided through a handheld manipulator or handheld robotic device, such as those described in U.S. Pat. No. 9,399,298, "Apparatus and Method for Providing an Adjustable Positive Stop in Space," U.S. Pat. No. 9,060,794, "System and Method for Robotic Surgery," and U.S. Patent Publication No. 2013 / 0060278, "Surgical instrument including housing, a cutting accessory that extends from the housing and actuators that establish the position of the cutting accessory relative to the housing," each of which is incorporated herein by reference in its entirety.

[0026] The monitoring system 101 is configured to determine the pose (i.e., position and orientation) of one or more objects and detect object movement during a surgical procedure. For example, the monitoring system 101 may include a detection device that obtains the pose of the object relative to a reference coordinate system of the detection device. The detection device monitors the pose of the object to detect (or allow the surgical system 100 to determine) the object's movement as it moves within the reference coordinate system. As a result, the computing system 102 can capture data in response to the movement of one or more monitored objects. The monitored objects may include, for example, tools / instruments, patient anatomy, implants / prosthetic devices, and components of the surgical system 100. The surgical system 100 may also use the pose data obtained from the monitoring system 101 to register (or map or relate) coordinates in one space to coordinates in another space to achieve spatial alignment or correspondence (e.g., using well-known coordinate transformation processes). Objects in physical space may be registered with respect to any suitable coordinate system, such as, for example, a coordinate system used by processes executed on a surgical controller and / or computing device of the robotic system 104. For example, the surgical system 100 may utilize pose data obtained from the monitoring system 101 to associate a physical anatomical structure, such as a patient's tibia, with a representation of that anatomical structure, such as an image displayed on the display device 103. Based on the monitored object and alignment data, the surgical system 100 may determine, for example, a spatial relationship between an image of the anatomical structure and its related anatomical structure.

[0027] Registration may include any known registration technique, such as, for example, image-to-image registration (e.g., unimodal registration, which registers images of the same type or modality, such as fluoroscopic or MR images, and / or multimodal registration, which registers images of different types or modalities, such as MRI and CT), image-to-physical space registration (e.g., image-to-patient registration, which registers a digital dataset of a patient's anatomy acquired with conventional imaging techniques to the patient's actual anatomy), combined image-to-image and image-to-physical space registration (e.g., registering preoperative CT and MRI images to an intraoperative scene), and / or registration using a video camera or ultrasound, etc. The computing system 102 may also include coordinate transformation operations to map (or transform) coordinates in one space to coordinates in another space to achieve spatial alignment or correspondence. For example, the surgical system 100 may use a coordinate transformation process to map the position of a monitored object (e.g., a patient's anatomy) to a coordinate system used by processes running on the haptic device and / or surgical controller computer. As is well known, the coordinate transformation process may include any suitable transformation technique, such as rigid transformations, non-rigid transformations, and affine transformations. In some embodiments, a video camera includes a tracker and bone scans to acquire and register the model. For example, an initial 3D model may be created and automatically registered. In some embodiments, a video camera may be used to register the 3D model corresponding to a CT scan. In some embodiments, a video camera or ultrasound may be used for both initial model creation and registration.

[0028] The monitoring system 101 may be any monitoring system that enables the surgical system 100 to continuously determine (or monitor) the pose of a patient's anatomy. For example, the monitoring system 101 may include a non-mechanical monitoring system, a mechanical monitoring system, or any combination of non-mechanical and mechanical monitoring systems suitable for use in a surgical environment. Non-mechanical monitoring systems may include optical (or visual), magnetic, radio, or acoustic monitoring systems. Such systems typically include a detection device adapted to locate, within a predefined coordinate space, a specially recognizable monitorable element (or tracker) that is detectable by the detection device and configured to be either attached to or an inherent part of the monitored object. For example, the monitorable element may include an array of markers that have a unique geometric arrangement and a known geometric relationship to the monitored object when the monitorable element is attached to the monitored object. The known geometric relationship may be, for example, a predefined geometric relationship between the monitorable element and an end point and axis of the monitored object. Thus, the detection device can recognize a particular monitored object, at least in part, from the marker's geometry (if unique), axis orientation, and endpoint location within a reference system derived from the marker's position.

[0029] Markers may include, for example, exogenous markers (or fiducials) and / or intrinsic features of the monitored object. Extrinsic markers are artificial objects attached to the patient (e.g., markers attached to the skin, markers implanted in bone, stereotactic frames, etc.) designed to be visible and accurately detected by a detection device. Intrinsic features are prominent and precisely locatable parts of the monitored object that are sufficiently defined and identifiable to function as recognizable markers (e.g., landmarks, anatomical contours, shape, color, or any other sufficiently recognizable visual indicator). Markers may be located using any suitable detection method, such as well-known optical, electromagnetic, radio, or acoustic methods. For example, an optical monitoring system having a pair of stationary infrared-sensitive stereo cameras may be used to monitor either active infrared-emitting markers (e.g., light-emitting diodes or LEDs) or passive infrared-emitting markers (e.g., spherical markers with infrared-reflective surfaces). Similarly, a magnetic surveillance system may include a stationary magnetic field generator that emits a spatially varying magnetic field that is sensed by small coils embedded within the object being monitored.

[0030] Computing system 102 may be communicatively coupled to monitoring system 101 and configured to receive monitoring data from monitoring system 101. Based on the received monitoring data, computing system 102 may determine a position and orientation associated with one or more registered features of the surgical environment, such as a portion of the patient's anatomy or the surgical tool 110. Computing system 102 may also include surgical planning and surgical support software that may be used by a surgeon or surgical support staff during a surgical procedure. For example, during a joint replacement procedure, computing system 102 may display images related to the surgical procedure on one or both of display devices 103 a, 103 b.

[0031] Computing system 102 (and / or one or more components comprising surgical system 100) may include hardware and software for operation and control of surgical system 100. Such hardware and / or software is configured to enable system 100 to perform the techniques described herein.

[0032] 2 illustrates a block diagram of a computing system 102 according to an exemplary embodiment. The computing system 102 includes a surgical controller 112, a display device 103 (e.g., display devices 103a and 103b), and an input device 116.

[0033] The surgical controller 112 may be any known computing system, but is preferably a programmable processor-based system. For example, the surgical controller 112 may include a microprocessor, a hard drive, random access memory (RAM), read-only memory (ROM), input / output (I / O) circuitry, and any other known computer components. The surgical controller 112 is preferably adapted for use with various types of storage devices (permanent and removable), such as, for example, portable drives, magnetic storage devices, solid-state storage devices (e.g., flash memory cards), optical storage devices, and / or network / internet storage devices. The surgical controller 112 may include one or more computers, such as, for example, a personal computer or workstation operating under a suitable operating system, and may include a graphical user interface (GUI).

[0034] Continuing with reference to FIG. 2 , in an exemplary embodiment, the surgical controller 112 includes a processing circuit 120 having a processor 122 and a memory 124. The processor 122 may be implemented as a general-purpose processor that executes one or more computer programs to perform actions by operating on input data and generating output. The processing and logic flow may also be performed by, and a device may be implemented as, dedicated logic circuitry, such as, for example, an FPGA (field-programmable gate array) or an ASIC (application-specific integrated circuit), a group of processing components, or other suitable electronic processing components. Generally, a processor receives instructions and data from read-only memory or random-access memory, or both. The memory 124 (e.g., a memory, memory unit, storage device, etc.) includes one or more devices (e.g., RAM, ROM, flash memory, hard disk storage, etc.) for storing data and / or computer code for completing or facilitating various processes described herein. The memory 124 may be or include volatile or non-volatile memory. Memory 124 may include database components, object code components, script components, and any other type of information structure to support the various operations described herein. In an exemplary embodiment, memory 124 is communicatively coupled to processor 122 and includes computer code for performing one or more operations described herein. Memory 124 may contain various modules, each capable of storing data and / or computer code related to a particular type of function. In one embodiment, memory 124 contains multiple modules related to a surgical procedure, such as a planning module 124a, a navigation module 124b, an alignment module 124c, and a robotic control module 124d.

[0035] Alternatively or additionally, the program instructions may be encoded on an artificially generated propagated signal, such as, for example, a machine-generated electrical, optical, or electromagnetic signal, generated to encode information for transmission to a suitable receiving device for execution by a data processing device. The computer storage medium may be or be contained in a computer-readable storage device, a computer-readable storage substrate, a random-access or serial-access memory array or device, or a combination of one or more of these. Furthermore, while the computer storage medium is not a propagated signal, the computer storage medium may be the source or destination of computer program instructions encoded on an artificially generated propagated signal. The computer storage medium may also be or be contained in one or more separate components or media (e.g., multiple CDs, disks, or other storage devices). Thus, the computer storage medium may be tangible and non-transitory.

[0036] A computer program (also known as a program, software, software application, script, or code) may be written in any type of programming language, such as a compiled or interpreted language, a declarative language, or a procedural language, and may be deployed in any form, such as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored within a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program, or in multiple associated files (e.g., a file storing one or more modules, subprograms, or code sections). A computer program may be deployed to be executed on one computer or on multiple computers located at one facility or distributed across multiple facilities and interconnected by a communications network.

[0037] Generally, a computer also includes one or more mass storage devices for storing data, such as a magnetic disk, a magneto-optical disk, or an optical disk, and / or is operatively connected thereto for transmitting and receiving data. However, a computer does not necessarily have such devices. Furthermore, a computer may be embedded in another device, including, for example, a mobile phone, a tablet, a personal digital assistant (PDA), a portable audio or video player, a game console, a global positioning system (GPS) receiver, or a portable storage device (e.g., a universal serial bus (USB) flash drive). Devices suitable for storing computer program instructions and data include all types of non-volatile memory, media, and memory devices, such as semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supported by or incorporated in dedicated logic circuitry.

[0038] Aspects of the subject matter described herein may be implemented in a computing system including a back-end component, such as, for example, a data server; a computing system including middleware components, such as, for example, an application server; a computing system including a front-end component, such as, for example, a client computer having a graphical user interface or web browser through which a user can interact with an aspect of the subject matter described herein; or any combination of one or more such back-end, middleware, or front-end components. The components of a system may be interconnected by any form or medium of digital data communication, such as, for example, a communications network.

[0039] Referring to the embodiment of surgical system 100 shown in FIG. 2 , surgical controller 112 further includes a communications interface 130. Communications interface 130 of computing system 102 is coupled to a computing device (not shown) of robotic system 104 via an interface and to monitoring system 101 via an interface. The interfaces may include physical and software interfaces. The physical interface of communications interface 130 may be or include a wired or wireless interface (e.g., jack, antenna, transmitter, receiver, transceiver, wire terminal) for data communication with an external source via a direct connection or a network connection (e.g., an internet connection, a LAN connection, a WAN connection, or a WLAN connection). The software interface may reside on surgical controller 112, the computing device (not shown) of robotic system 104, and / or the monitoring system 101. In some embodiments, surgical controller 112 and the computing device (not shown) are the same computing device. The software may also run on a remote server housed within the same building as the surgical system 100 or at an external server facility.

[0040] Computing system 102 also includes a display device 103. Display device 103 is a visual interface between computing system 102 and a user. Display device 103 is connected to surgical controller 112 and may be any device suitable for displaying text, images, graphics, and / or other visual output. For example, display device 103 may include a standard display screen, a touchscreen, a wearable display (e.g., eyewear such as glasses or goggles), a projection display, a head-mounted display, a holographic display, and / or any other visual output device. Display device 103 may be located on or near surgical controller 112 (e.g., on a cart as shown in FIG. 1 ) or may be remote from surgical controller 112 (e.g., mounted on a stand along with monitoring system 101). Display device 103 is preferably adjustable to allow a user to position and reposition display device 103 as needed during a surgical procedure. For example, the display device 103 may be located on an adjustable arm (not shown) or in any other suitable location for easy viewing by a user. As shown in FIG. 1, there may be more than one display device 103 in the surgical system 100.

[0041] The display device 103 may be used to display any information useful in a medical procedure, such as, for example, images of anatomical structures generated from image datasets acquired using conventional imaging techniques, graphical models (e.g., CAD models of implants, instruments, anatomical structures, etc.), graphical representations of monitored objects (e.g., anatomical structures, tools, implants, etc.), constraint data (e.g., axes, articular surfaces, etc.), representations of implant components, digital or video images, alignment information, calibration information, patient data, user data, measurement data, software menus, selection buttons, and status information.

[0042] In addition to the display device 103, the computing system 102 may include an acoustic device (not shown) for providing audible feedback to the user. The acoustic device is connected to the surgical controller 112 and may be any known device for producing sound. For example, the acoustic device may include a speaker and sound card, a motherboard with built-in audio support, and / or an external sound controller. In actual operation, the acoustic device may be adapted to convey information to the user. For example, the surgical controller 112 may be programmed to send a signal to the acoustic device to produce a sound, such as a synthesized voice verbal instruction saying "DONE," indicating that a stage of a surgical procedure is complete. Similarly, the acoustic device may be used to alert the user to sensitive conditions, such as producing a tone to indicate that a surgical cutting tool is approaching a critical area of ​​soft tissue or approaching a virtual control boundary.

[0043] Aspects of the subject matter described herein may be implemented on a computer having input devices 116 that allow a user to communicate with the surgical system 100 to provide other user interactions. The input devices 116 are connected to the surgical controller 112 and may include any device that allows a user to provide input to the computer. For example, the input devices 116 may be known input devices such as a keyboard, mouse, trackball, touchscreen, touchpad, voice recognition hardware, dials, switches, buttons, monitorable probes, foot pedals, remote control devices, scanners, cameras, microphones, and / or joysticks. For example, the input devices 116 may allow a user to manipulate a virtual control boundary. Other types of devices may also be used to provide user interaction; for example, feedback provided to the user may be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback, and input from the user may be received in any form, such as acoustic input, speech input, or tactile input. Additionally, a computer may interact with a user by sending documents to and receiving documents from a device used by the user, such as by sending a web page to a web browser on the user's client device in response to receiving a request from the web browser.

[0044] General surgical planning and navigation for implementing the exemplary methods of the present invention, including the haptic control and feedback described above and in connection with surgical system 100, may be performed by a computer-assisted surgical system such as the system described in U.S. Pat. No. 8,010,180 to Quaid et al., entitled "Haptic Guidance System and Method," which is incorporated herein by reference in its entirety.

[0045] Virtual objects for robotic-assisted surgery 3A-3B show example x-ray images showing a femur (F), a tibia (T), a femoral implant 302, and a tibial implant 306 according to an exemplary embodiment. While x-ray images are shown in FIGS. 3A and 3B, other images may be acquired using any of a variety of imaging techniques (e.g., CT, MRI, ultrasound, video camera, etc.) and used to generate the bone model. As shown, femoral implant 302 includes a protrusion, such as a peg 304, extending into femur F, and tibial implant 306 includes a keel 308, for example. During implantation, cement is provided under the flat portion of the base plate of tibial implant 306 and on the flat surfaces of femoral implant 302. In some embodiments, femoral implant 302 includes five flat portions: portion ab, portion bc, portion cd, portion de, and portion ef. In some embodiments, cement is placed over some or all of the flat portion of the femoral implant 302. During revision surgery, implants 302 and 306, including pegs 304 and keel 308, must be milled around for removal. However, over time, keel 308 may have ingrowth from the tibia T, which can result in bone fragments detaching during the removal procedure. To reduce bone loss during removal, images of the implant (e.g., images obtained by CT, MRI, video, ultrasound, etc.) may be used to create a bone and implant model for generating a surgical plan for removal. In some embodiments, a monitoring probe may be used to probe areas near points a, b, c, d, e, and f, or along the edges of portions ab, bc, cd, de, and ef, for example, to generate a model of the interface between the femoral implant 302 and the bone.

[0046] FIG. 4 illustrates a graphical user interface showing a model of a bone 402 and a model of an implant 404 during a primary partial knee replacement procedure, according to an exemplary embodiment. Specifically, FIG. 4 depicts the distal end of a femur 402 receiving a femoral implant 404. As shown, the femoral implant 404 includes an elongated projection 406 (e.g., a peg, screw, keel, etc.) received by an opening in the femur. The elongated projection 406 further securely fixes the femoral implant 404 to the bone 402 and helps resist movement between the implant 404 and the bone 402. To improve secure fixation between the bone 402 and the implant 404, the bone may be prepared with a keel (not shown) that interfaces with a keel on the femoral implant 404. The model may allow a user to modify the view of the implant model through rotating the model or selecting different view modes. In some embodiments, the model may allow a user to view different cross-sectional views of the implant, bone, or a combination thereof. In some embodiments, the model may also provide information (eg, size, location, materials, etc.) to aid in planning a revision surgery.

[0047] 1 may be configured to establish virtual control objects related to the current prosthetic implant components and related to or relating to one or more features of the patient's anatomy. The surgical system 100 may be configured to create a virtual representation of the surgical site, including, for example, virtual representations of the patient's anatomy, surgical instruments used during the surgical procedure, probe tools for aligning other objects within the surgical site, and any other objects associated with the surgical site.

[0048] In addition to physical objects, the surgical system 100 may be configured to generate virtual objects that exist in software and may be useful during the performance of a surgical procedure. For example, the surgical system 100 may be configured to generate virtual boundaries or virtual control boundaries that correspond to a surgeon's plan for bone preparation, such as boundaries that define areas of bone the surgeon plans to cut, remove, or otherwise modify. In the case of revision surgery, the virtual boundaries may correspond to the surgeon's plans for cement removal and the bone configuration required for the interface between an implanted prosthetic component and its implanted bone. Alternatively or additionally, the surgical system 100 may define virtual objects that correspond to a desired path or course that a portion of the surgical tool 110 (e.g., the end effector 200) should follow to perform a particular task.

[0049] The surgical system 100 may also be configured to generate virtual objects or boundaries as part of a specific surgical plan. In some embodiments, the surgical plan is generated based on a database of implants, corresponding to a registered model of the implant or bone. If the implant is known in the database, a surgical plan may be suggested to the user. The surgical plan may include which tools to use; what access is needed to move around parts such as the implant, virtual boundaries; etc. The suggested surgical plan may include virtual objects around the keel and pegs and suggest tool changes to cut around these features of the implant. In some embodiments, the surgical plan is modifiable by the user, including, but not limited to, the tools used, the access needed, and the shape of the implant and virtual boundaries. In some embodiments, the general surgical plan may be automatically modified based on a model capture of the patient's anatomy or implant, or a specific implant.

[0050] Virtual boundaries and other virtual objects may define points, lines, or surfaces in virtual coordinate space (typically defined relative to the patient's anatomy) that serve as boundaries that provide constraints to the surgical instrument when the monitored position of the surgical instrument interacts with the virtual boundary or object. In some embodiments, constraints are provided through haptic or force feedback. For example, as the surgeon performs a bone-cutting operation, the monitoring system of surgical system 100 monitors the position of the cutting tool and, in most cases, allows the surgeon to move the tool freely within the workspace. However, when the tool is in proximity to a virtual boundary (aligned with the patient's anatomy), surgical system 100 controls the force feedback system to provide guidance that tends to constrain the surgeon from penetrating the virtual boundary with the cutting tool. For example, the virtual boundary may be related to the geometry of a virtual model of a prosthetic implant, and the haptic guidance may include forces and / or torques that are mapped to the virtual boundary and experienced by the surgeon as resistance to constrain the tool's movement from penetrating the virtual boundary. Thus, the surgeon may feel as if the cutting tool has encountered a physical object, such as a wall. Accordingly, the haptic feedback system of surgical system 100 communicates this information to the surgeon regarding the tool's position relative to the virtual boundary and provides physical haptic feedback to guide the cutting tool during the actual cutting process. In this manner, the virtual boundary acts as a virtual cutting guide. The haptic feedback system of surgical system 100 may also be configured to limit the user's ability to manipulate the surgical tool. A robotic system or manual tool may be attached to the implant to measure the force applied for removal. Monitoring the implant's position relative to the bone and the applied force may provide the surgeon with an indication of the ease of removal, which may indicate the need for additional cutting to minimize unintentional bone loss.In some embodiments, the virtual boundary may define autonomous cutting control, allowing the surgical robot to autonomously perform all or some stages of the surgical plan. In some embodiments, the virtual boundary defines a combination of autonomous and manual cutting boundaries. In some embodiments, when using autonomous cutting control, feedback may be used to indicate when contact with the implant occurs (e.g., when the tool is cutting along a flat interface surface and contact occurs with a peg), and based on that feedback, the surgical plan or boundary may be adjusted to avoid that portion of the implant. For example, this may be particularly useful when the shape of the keel is not known or identifiable before cutting begins, and therefore the original boundary does not account for the keel. Based on detected differences in the surgical plan and / or the virtual boundary and the keel, the surgical plan or virtual boundary may be modified. In some embodiments, the virtual boundary corresponds to a haptic boundary that defines a haptic object. In some embodiments, the haptic boundary is configured to provide haptic feedback when the haptic boundary is encountered. The haptic boundary may provide tactile, auditory, visual, or olfactory (ie, smell) tactile feedback, or other means of providing feedback.

[0051] In some embodiments, the rendering application may also create a virtual object (not shown) representing a path from a first position to a second position. For example, the virtual object may include a virtual guidewire (e.g., a line) that defines a path from a first position (e.g., a position in physical space of a tool used with the surgical system 100) to a second position that includes a target (e.g., a target object, such as a virtual object). The virtual object may be activated such that movement of the tool is constrained along the path defined by the virtual object. The surgical system 100 may deactivate the object when the tool reaches the second position and activate the target object (e.g., a virtual object). The tool may automatically be placed into a control mode, such as haptic control (or burring), when the object is activated. In a preferred embodiment, the object may be deactivated to allow the tool to deviate from the path. Thus, a user can override the guidance associated with the object to deviate from the path of the guidewire and maneuver the tool around unmonitored objects (e.g., screws, retractors, lamps, etc.) that were not taken into account when the virtual guidewire was generated.

[0052] In control mode, the robotic system 104 is configured to provide guidance to the user during surgical tasks, such as bone preparation. In one embodiment, the rendering application may include a virtual object defining a cutting volume of the tibia T. The virtual object may have a shape that substantially corresponds to the shape of the surface of the tibial component, for example, during implant preparation. In revision surgery, the virtual object may have a shape that substantially corresponds to the shape of the interface between the tibial component and the host tibia, or the shape of the path to be taken for bone removal. The robotic system 104 may automatically enter control mode, for example, when the tip of a tool approaches a predefined point on a feature of interest. In some embodiments, the tool may be disabled when outside the virtual object. In another embodiment, the tool may be disabled if the robotic system 104 is not generating control feedback forces.

[0053] In actual operation, the surgical system 100 may be used for surgical planning and navigation. In addition to preparation for revision surgery, the surgical system 100 may also be used to perform, for example, knee replacement procedures or other joint replacement procedures involving the introduction of implants. The implants may include any implant or prosthetic device, such as, for example, a total knee implant; a unicompartmental knee implant; a modular knee implant; implants for other joints, including the hip, shoulder, elbow, wrist, ankle, and spine; and / or any other orthopedic and / or musculoskeletal implant, including implants made from conventional materials and more advanced implants, such as orthobiologics, drug delivery implants, and cell delivery implants.

[0054] Robotic revision surgery Revision surgery, such as revision knee arthroplasty, is a complex procedure requiring a very high level of expertise. There are several factors that further complicate the procedure. The surgeon must remove the original implant, which may or may not be cemented. The implant may have bone growing into it, and the surgeon must strive to preserve as much bone as possible while removing the original implant. Furthermore, the implant may contain surfaces, keels, pegs, screws, or other components that must be cut around or through it. In some embodiments, the implant may be multiple implants that must be individually cut around and removed. The surgeon must ensure that the majority of the cement-to-bone and / or implant-to-bone bonds are broken, making the process complicated and time-consuming. Existing solutions require the surgeon to remove the bone-to-implant or bone-cement interface with manual or powered instruments. These instruments include osteotomes, gigli saws, and trepaners. Powered instruments, such as powered saws and burrs or ultrasonic devices, are also available. Although attempts are made to preserve bone, some bone loss always occurs, and the surgeon must accurately fill all bone defects resulting from bone loss during implant removal. There may also be pre-existing bone defects that require attention after implant removal. The robotic system and specialized instrumentation of the present disclosure help to solve some of the problems that arise during implant extraction.

[0055] Reasons for revision surgery include, for example, infection, malalignment, and wear. In infected revision knee arthroplasty, the surgery may be a two-stage procedure. In the first stage, the infected implant is removed and the wound is decontaminated. A spacer block is added to the joint and the wound is closed. In the second stage, the spacer is removed and a new revision implant is added.

[0056] The present disclosure addresses problems previously encountered in revision knee and / or hip arthroplasty by using a robotic-assisted approach. The present disclosure also describes a flexible end effector equipped with a high-speed cutting burr. The flexible end effector is highly sensitive to access small areas, such as the posterior surface of the tibia, for implant removal. Referring to FIGS. 5A-5C, a flexible end effector 200 is shown that may be used with a robotic arm 106 to perform robotically assisted revision hip and knee arthroplasty procedures, according to an exemplary embodiment. In some embodiments, the flexible end effector 200 may be an end effector based on any of the embodiments described in U.S. Patent Application No. 15 / 436,460, which is incorporated herein by reference in its entirety.

[0057] Manual removal of implants can be difficult due to limited access to certain bone regions, such as the posterior tibia. Flexible end effector 200 can expand the capabilities of a robotic arm to access these small areas. As shown in FIGS. 5A and 5B, flexible end effector 200 includes two flexible bend elements 202 and 204. Each element has two degrees of freedom and can bend less than or more than 90 degrees in three-dimensional space, as shown in FIG. 5C. End effector 200 may include a large internal channel for mounting a flexible shaft. The flexible shaft is, for example, a hollow tube with a thin wall thickness that can spin a cutting burr. In some embodiments, the hollow tube can spin a cutting burr at 60,000 rpm. The internal channel of the flexible shaft may also be used for irrigation or aspiration channels. In some embodiments, flexible elements 202 and 204 provide increased access to areas that are otherwise difficult to reach.

[0058] The end effector 200 includes a housing 206 with a base 208 and a mount 210. The base 208 securely fastens the end effector 200 to the robotic arm 106 and provides stability to the end effector 200. The mount 210 securely fastens a shaft 212 of the end effector 200. The shaft 212 houses a motor 214 that provides power to a cutting tool 216 located at the distal end of the end effector 200. In some embodiments, the end effector 200 also includes a suction lumen 218. The suction lumen 218 connects to an internal channel of the flexible shaft. In some embodiments, the robotic arm 106 may be fixed, and the end effector 200 may move autonomously to perform the planned cut, as described below.

[0059] Various cutting tools 216 may be selected depending on the type of bone cut to be completed. A saw may be used for flat cuts; a burr may be used for curved surfaces; a curved saw may be used to gain access around pegs, keels, and / or screws (which may be cut around or through and removed individually); or another cutting tool may be used that is more suited to the bone access and type of cut to be made. For critical areas at the posterior knee, a curved tool, or a tool capable of making curved cuts, is preferred. In an exemplary embodiment, a saw may be used to make the initial cut, and then more specific cuts may be made using a specialized end effector 200. In some embodiments, an ultrasonic tool may be used to vibrate and break down bone cement for removal. In some embodiments, a laser may be used to melt the cement. In some embodiments, a water jet may be used to cut or break down the cement.

[0060] 6A-6C show various views of a femur F, a femoral implant 302, and another exemplary embodiment of an end effector 200. The end effector 200 in FIGS. 6A-6C may include a base 208, a mount 210, and a cutting tool 216. The end effector 200 may be an oscillating chisel. In some embodiments, the cutting tool can scrape and cut cement between the bone and the implant. The end effector 200 may be controlled and advanced by the surgeon but may be constrained by a haptic boundary located between the bone and the implant to reduce the skiving effect and access all cement deposits to preserve as much bone as possible. The end effector 200 may be used during revision surgery to remove an implant by cutting along sites ab, bc, cd, de, and ef. The end effector may also be used to prepare the bone for a new implant. The bone may be prepared by using milling tool 216 or various other milling tools to create surfaces ab, bc, cd, de, and ef as well as peg holes 310 for receiving pegs 304 .

[0061] 7A and 7B show a femoral implant 302 after removal from the femur, if the removal was performed manually or without a robotic system. As can be seen, in some revision surgeries, excessive bone is removed during implant 302 removal, as shown by the bone 312 remaining on the implant 302. When excessive bone is removed, an uneven surface 314 is created on the bone. Excess bone removal often occurs immediately around the keel or pegs or behind the implant, where cutting cement is difficult. To properly prepare the bone for the new implant, it may be necessary to fill the defect with augmentation materials, cones, or other filling methods. To assist in planning defect correction and reimplantation, video or ultrasound techniques may be used to determine the characteristics of the remaining bone after implant removal.

[0062] The surgeon may perform the revision procedure using a robotic system to assist in the removal of the primary implant using various methods described below.

[0063] FIG. 8 is a flowchart of a method 800 for performing revision surgery, according to an exemplary embodiment. Before the procedure begins, information regarding the interface region between the implanted implant component and the bone into which it is implanted must be obtained. This may be accomplished using images of the revision site or other tools for understanding the relationship without images. These variations for obtaining interface information, shown as optional steps 802, 804, and 806 in FIG. 8, are described below.

[0064] A first exemplary embodiment of a method for revision surgery utilizes images of the patient's anatomy to plan the revision surgery. If the patient's primary case (e.g., initial surgery) was performed with a robotic-assisted system, the bone model and implant information may already be available, and images do not need to be recaptured to perform the revision surgery. During revision surgery, the primary bone model and implant information for the patient's knee and hip joints are available to the robotic-assisted system, as shown in FIG. 4. In addition, implant models are known and stored in the surgical system's library for use during planning.

[0065] In other cases, patient imaging data may not be available or new images may be desirable. Therefore, an initial or new scan must be performed prior to planning and performing the revision procedure. In such embodiments, as shown in optional step 802, the patient's anatomy is imaged using any suitable imaging modality, such as a CT or MRI scan, fluoroscopy, ultrasound, monitored markers, or a video camera. The images captured by the imaging device are used to create bone and implant models for use in the planning stage. (In some embodiments, in the case of a two-stage revision procedure, imaging may be performed after implantation of the spacer blocks. The spacer blocks may have features that allow for alignment of the spacer blocks during the implantation procedure.) In some embodiments, a robotic device may be attached to the imaging device for intraoperative alignment and monitoring. Next, in optional step 804, the scan results are segmented or converted into a bone model. The scan results may be segmented in a predefined manner, or the surgeon may be able to select the segmentation parameters. In some embodiments, when using a video camera, a 3D model may be created without segmentation. In some embodiments, a 3D model may be created using imaging, such as a statistical model. As described above, registration of images to physical space / anatomy is performed by the surgical system 100.

[0066] In another exemplary embodiment in which image data regarding the patient's anatomy is not captured or used, the method of the present invention may capture data intraoperatively in optional step 806. In this step, the perimeter of the cement-to-bone or implant-to-bone interface is digitized using a monitored probe. Position data of the monitored probe is captured by a monitoring system, such as monitoring system 101, to determine the location of the interface to be debonded. If image data, a bone model, and / or an implant model are available and / or used for planning, digitization of the interface may also be performed in addition to the model. The implant may then be aligned with the primary bone model. In yet another embodiment, a camera or optical sensor may be coupled to a robotic arm to scan the implant surface and align it with the bone model. In another embodiment, a video camera may be moved around the patient to scan the bone and implant surface and create a 3D model. The surface of the implant may be probed to align a known implant location or known features of the implant. In some embodiments, if the implant is known, probing may identify and align the implant with the implant model.

[0067] In step 808, the implant removal cut is planned. In one embodiment, where image data from a preoperative scan is available (whether a recent scan or a scan at the time of the primary implantation surgery), the removal cut may be based on that image and the location of the cement-to-bone or implant-to-bone interface. In some embodiments, a video camera is used to define planes and virtual boundaries. In some embodiments, a probe may be used to define planes and virtual boundaries. Alternatively, the removal cut may be based on the intended replacement implant. In this manner, the planned resection cut may be planned to properly accommodate the new implant while allowing for removal of the current implant. In some embodiments, the planning software generates a bone preparation plan to achieve proper alignment for the patient, such as proper alignment of the tibia and femur. In some embodiments, the robotic system 104 helps the surgeon plan and perform proper alignment of the knee joint in 3D. The bone preparation plan may be performed automatically by the planning software, or the surgeon may assist in creating the bone preparation plan. Previous imaging data (e.g., X-ray, CT, MRI, fluoroscopy, video) and intraoperative landmarks may be used to visualize ideal natural anatomical structures, such as joint lines. The system of the present invention may also use range of motion and soft tissue compliance as inputs to assist in procedural planning. In some embodiments, fiducials may be placed on the spacer block to expedite alignment for reimplantation surgery. After implant removal, robotic or manual tools may be used to remove remaining cement. A handheld monitored probe or a probe attachment for a robotic arm may be used to identify the remaining cement in the 3D model. The model may be used to create a separate robotic cutting path for cement removal.

[0068] In other embodiments, the planning of the implant removal cuts in step 808 may be based on data collected by a digitizing probe. Typically, a total knee replacement implant design includes multiple flat surfaces that face the bone. During digitization, points on each surface of the implant may be collected to identify these planes. The robotic system uses the surrounding data to calculate a plan for separating the interface of interest. The probe is used to collect points to define planes that can be used for the virtual boundary. Probing the transition region of the implant (the point between two flat surfaces) can help identify the virtual boundary. Intraoperative imaging or the use of a video camera can create a model of the bone defect after implant removal. Updates to the existing model may be made by probing the defect to indicate where additional bone loss exists. This defect model may be used to plan a revision implant to ensure the selection of an appropriate implant to cover the defect. The defect model indicates the need for additional augmentation devices to fill the defect. After the revision implant is selected, a virtual boundary for the bone cut to insert the implant is created. Once the model and defect model are created, a new plan may be generated to perform the bone modifications and additions required by bone loss to accommodate the insertion of new implants.

[0069] As part of this planning step 808, the surgical system 100 generates control objects, such as haptic objects, as described above. The control objects may define a virtual boundary corresponding to the surgeon's plan for bone preparation. Specifically, in the case of a revision procedure, the virtual boundary relates to the portion of the interface area that the surgeon plans to cut, remove, or otherwise modify to remove the current implant from the bone. A revision virtual boundary is created around at least a portion of the interface area to allow the surgeon to precisely cut the bond area between the bone and the implant. In a preferred embodiment, the revision virtual boundary is created adjacent to the implant surface to protect the bone from overcutting. In this manner, the revision boundary is believed to minimize bone removal and reduce the risk of bone separation, potentially increasing the number of revision procedures that can be performed during the patient's lifetime. The boundary may be a planar boundary to which the cutting tool is constrained by the virtual boundary, or it may be a contoured boundary of any shape. The boundary may be created automatically by the system based on received image and position data, or it may be created manually based on user input. In other embodiments, the boundary may be customizable or adjustable; for example, the surgeon may choose to move the boundary closer or further from the interface to accommodate bone quality. The robotic system may use control objects that define the virtual boundary to ensure that the cutting tool does not move outside the desired cutting area, that minimal bone is removed, and that the cut is performed precisely. If the implant is known, the virtual boundary may be identified along with a proposed surgical plan. The proposed surgical plan may be used as a starting template for the surgeon, which can be modified to suit the specific needs and / or conditions of the surgery. In some embodiments, the proposed plan is generic. In some embodiments, the proposed plan provides suggested tools and / or suggested access locations for preparing the bone for implant features, such as keels, pegs, or any other structures or shapes that need to be avoided.In some embodiments, a generic template of the shape may be used to plan the virtual boundary, or a custom shape may be drawn, created, or selected during surgical planning. In particular, the surgical plan may not be customized based on the characteristics of the bone remaining after removal of the initial implant. In some embodiments, the access location and dimensions may be identified in the proposed surgical plan. In some embodiments, the approach path may be outlined in the proposed surgical plan.

[0070] In some embodiments, the planning software may also determine the size and number of augments needed in step 810. The planning software may select the size of the augments based on a database of information. In another embodiment, the planning software allows the user to input the size and number of augments needed. For example, the surgeon may instruct the system via a graphical user interface to add a 5 mm posterior augment or a 20-degree medial tibial wedge, and the planning software allows such cuts to be performed by surgical tools coupled to a robotic arm rather than a threading fixture. Preoperative augment sizing and planning, enabled by the use of a robotic system according to exemplary embodiments disclosed herein, saves valuable time in the operating room and increases the efficiency and accuracy of the procedure.

[0071] In step 812, the robotic system 104 monitors the movement of the cutting tool using the navigation system 101 and guides the surgeon while the planned cut is being made. The system 104 may guide the execution of the cut by providing constraints on the cutting tool based on the relationship between the virtual tool (associated with the cutting tool) and the virtual boundary. Haptic guidance may be provided based on control objects generated by the system corresponding to the surgical plan, or the system may perform the cut autonomously. If haptics is used, the surgeon receives feedback indicating when a haptic boundary is reached, which prevents the surgeon from removing too much bone. In some embodiments, the surgeon may perform the cut using a combination of haptic control and autonomous action. In some embodiments, the robotic system may also provide feedback regarding the bone-implant or bone-cement fracture process. For example, the robotic system may provide the surgeon with information regarding the progression of cement-bone or implant-bone interface fracture. This may prevent unintended bone loss during implant extraction if the interface is not properly fractured.

[0072] In some embodiments, the robotic system 104 may remove the hardware by impact. The robotic system may "jolt" the implant loose using the force of a robotic arm or through the use of an end effector that acts like a woodpecker.

[0073] The use of a robotic system allows for the use of various cutting tools based on the type of bone cut to be completed. A saw may be used for flat cuts; a burr may be used for curved surfaces; a curved saw may be used to gain access around pegs or keels and / or around or through screws; or another cutting tool may be used that is more suited to the bone access and type of cut to be made. The robotic system monitors the cutting tool and the patient to monitor the cutting procedure and provide the user with information regarding the progression of cement-bone or implant-bone interface failure. As above, this reduces unintended bone loss that can occur when an implant is pulled before the interface has properly debonded. In some embodiments, the value of the surface resection, such as a percentage, may be displayed, which can provide the surgeon with an indication as to the appropriate time to attempt implant removal. In some embodiments, the display may show the amount of bone removal for a particular region of interest if the surgeon is concerned about bone loss in that region. In some embodiments, the surgeon may identify specific regions of interest to be calculated preoperatively or intraoperatively.

[0074] Additionally, a robotic system or manual tool may be attached to the implant to measure the force applied for removal. Monitoring the implant's position relative to the bone and the force applied may provide the surgeon with an indication of ease of removal, which may indicate the need for additional cutting to minimize unintentional bone loss.

[0075] If there is a bone defect after implant removal that the planning software did not account for, the bone defect may be digitized or otherwise identified in optional step 814. In step 816, the planning software may generate sizing information for filling the defect with various implants or biomaterial fillers. The implants and / or biomaterial fillers may be selected from a database of available implants or fillers. In some embodiments, the software may generate a plan for filling the defect and create a custom implant or filler. In some embodiments, the software selects the implant and / or biomaterial filler based on multiple factors (e.g., defect size, bone density, etc.). In some embodiments, the robotic system 104 can determine the appropriate size of a cone to use to fill the defect. In other embodiments, bone filler material may be cut to fit the size of the defect, or the system may be configured to inject a liquid filler into the defect that can solidify within the patient's body.

[0076] In step 818, the planning software determines the desired pose of the replacement implant within the bone and plans the bone preparation to receive the replacement implant. Planning and control object creation may occur in a manner similar to that described for step 808. In addition to performing the steps described above, there are multiple ways in which the robotic system can assist in revision procedures. Regarding planning and preparation for implanting new implant components, the display device 103 may display a limb alignment / balancing screen to assess how the implant will fit, which may aid in planning the adjustment. Additionally, the system may assist in assessing stem length, straight or curved, cemented or press-fit, etc., based on bone morphology, quality, adjacent hardware, etc. Assessments may be patient-specific or predicted from a predefined dataset. In another embodiment, the robotic system may apply distraction via leg holders, spreaders, balancers, etc., to assess and define collateral tension. This may be done in multiple poses, and a graphical user interface and internal algorithms may be utilized to calculate the joint line placement and component sizes that best restore kinematics and function. In yet another aspect, the robotic system may be used to assist in revision surgery of partial, bicompartmental, or tricompartmental knee prostheses to cruciate-sparing, cruciate-substituting, or posterior-stabilized knee prostheses.

[0077] A video camera may also be used to create a model of the bone after implant removal in step 814. This identifies the current bone geometry without the implant, including any bone defects requiring attention. The video camera and the images it captures may then be used to plan the bone cuts in step 818, perform the bone cuts to prepare the bone for the replacement implant, and place the implant in step 820 (described below). In some embodiments, the video camera may be used in other phases of the procedure, such as creating a model, aligning it, or monitoring the anatomy or the position of surgical tools used during the procedure. In some embodiments, the model may also include incision identification, either by selecting edges in the system software using color identification or image detection of the retractor holding the incision, or by applying a material around the incision that can be detected by the camera. The video camera may then also be used to monitor the position of the incision during the procedure.

[0078] In step 820, cuts are performed to prepare the bone surface for placement of augmentation materials, cones, filler materials, and the final implant. The surgeon may perform the bone preparation cuts with guidance from a system, such as haptic feedback. In another embodiment, the robotic system 104 may perform the preparation cuts autonomously. As described above, the system may resect bone according to the new plan as a step to remove existing hardware. Thus, instead of sawing / scraping away the existing implant, a cut is made to aid in the removal of the implant and provide the appropriate cut for the next implant.

[0079] In some embodiments, the robotic system may be used in additional ways while making cuts to bone. For example, the system may support adaptive cutting, where the next cut may be made based on various inputs, such as previous cut data or other landmarks / targets. For example, a probe may define, for example, the distal facet and posterior tangent, and the remaining cut may be made according to the defined size of the implant (femur, tibia, or patella). The input may be the existing resection or the desired joint contact. Based on the input, a calculated cut may be programmed to achieve the desired outcome. Additionally, the system may be used to refine the cut. The surface may be probed, and then a grazing cut (e.g., a 0.5-1 mm cut) may be made. Control boundaries, such as haptics, may be updated or generated during the procedure as the cut is being made. In another example, the robotic system 104 may control saw performance based on bone quality. Extremely soft / spongy bone or hard, hard bone may require a "lighter" or "harder" touch on speed and / or feed, or may even require a different blade.

[0080] The robotic system may also assist with implant placement and post-implant evaluation. For example, a display device showing a graphical user interface may be used to guide the surgeon regarding offset or angled couplers for stemmed femoral or tibial component placement, or to guide the surgeon in slight manipulation of the anterior-posterior or medial-lateral position to reduce apical or cortical stress points. Additionally, a robotic arm may be used to hold the implant in place relative to the bone while the cement cures. In yet another embodiment, the system may aid in the assessment of sufficient stability of the new construct via a range of motion / balancing graphical user interface.

[0081] In some embodiments, the robotic system 104 may visualize the implant path or cement area when considering other aspects of the surgery, such as when the tibial tuberosity is translated and a tibial window where hardware, such as a trauma plate, resides is cut and moved relative to the knee implant.

[0082] The structure and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. While only a few embodiments have been described in detail in this disclosure, numerous modifications are possible (e.g., variations in the size, dimensions, structure, shape, and proportions of various elements, parameter values, material use, color, and orientation, etc.). For example, the positions of elements may be reversed or otherwise changed, and the nature or number or position of individual elements may be altered or changed. Accordingly, all such modifications are intended to be within the scope of this disclosure. The order or sequence of any process or method steps may be changed or rearranged in alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of this disclosure.

[0083] The present disclosure contemplates methods, systems, and program products on any machine-readable medium for accomplishing various operations. Aspects of the present disclosure may be implemented using an existing computer processor, by a special-purpose computer processor for a suitable system incorporated for this or another purpose, or by a hardwired system. Aspects within the scope of the present disclosure include program products including machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media may be any available medium that can be accessed by a general-purpose or special-purpose computer or other machine with a processor. By way of example, such machine-readable media may include RAM, ROM, EPROM, EEPROM, CD-ROM, or other optical disk storage; magnetic disk storage; other magnetic storage devices; solid-state storage devices; or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and that can be accessed by a general-purpose computer, special-purpose computer, or other machine with a processor. When information is transferred or provided over a network or another communications connection (hardwired, wireless, or a combination of hardwired or wireless) to a machine, the machine properly views the connection as a machine-readable medium. Thus, any such connection is properly termed a machine-readable medium. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data that cause a general-purpose computer, special-purpose computer, or special-purpose processing machines to perform a certain function or group of functions.

[0084] While a particular order of method steps may be described, the order of steps may differ from that described. Also, two or more steps may occur simultaneously or with partial concurrence. Such variations will depend on the software and hardware systems selected and designer choice. All such variations are within the scope of this disclosure. Similarly, software embodiments may be implemented with standard programming techniques involving rule-based logic or other logic to implement any connecting, processing, comparing, and deciding steps.

Claims

1. A robotic device; a cutting tool coupled to the robotic device; A probe; a navigation system configured to monitor the position of the probe and to monitor the position of the bone using markers coupled to the bone into which the primary implant component is implanted; 1. A computing system including an input device and a graphical user interface, acquiring position data from the navigation system in response to user input received from the input device via the graphical user interface, the position data indicating the position of the probe in contact with an interface region between the bone and the primary implant component implanted in the bone; using position data of the probe to intraoperatively generate, without preoperative medical imaging, a virtual boundary corresponding to a portion of the interface region to be removed to release the primary implant component from the bone; and controlling the robotic device based on a relationship between the cutting tool and the virtual boundary to facilitate removal of the primary implant component using the cutting tool. A computing system programmed to A surgical system comprising:

2. the positions of the probe correspond to points on a plurality of surfaces of the primary implant component; the computing system is programmed to generate the virtual boundary by identifying one or more planes of the primary implant component based on the points on the surfaces of the primary implant component. The surgical system of claim 1 .

3. 10. The surgical system of claim 1, wherein the computing system is further configured to control the robotic device to facilitate preparing the bone to receive a revision implant component based on a second relationship between the cutting tool and a second virtual boundary representing a portion to be cut from the bone to prepare the bone to receive the revision implant component.

4. The surgical system of claim 1 , wherein the computing system is further programmed to create a model of the bone defect after removal of the primary implant component from the bone.

5. The surgical system of claim 4 , wherein the surgical system further comprises a video camera, and the computing system is programmed to generate a model of the bone defect based on input from the video camera.

6. The surgical system of claim 4 , wherein the computing system is further programmed to update the model of the bone defect with additional position data of the probe monitored by the navigation system.

7. The surgical system of claim 4 , wherein the computing system is further programmed to generate a plan for placing a revision implant and an augmentation or filler material based on the model of the bone defect.

8. A non-transitory computer-readable memory storing a program executable by a processor included in a computing system including an input device and a graphical user interface, comprising: receiving monitoring data from a navigation system that monitors the position of the probe; receiving monitoring data from the navigation system that monitors the position of the bone using markers coupled to the bone in which the primary implant component is implanted; acquiring position data from a navigation system in response to user input received from the input device via the graphical user interface, the position data indicating a position of the probe in contact with an interface region between the bone and the primary implant component implanted in the bone; using the position data of the probe to intraoperatively generate, without preoperative medical imaging, a virtual boundary corresponding to a portion of the interface region to be removed to release the primary implant component from the bone; generating a control configured to provide a constraint to a cutting tool to facilitate removal of the primary implant component from the bone by removal of the portion of the interface region with the cutting tool; A non-transitory computer-readable memory storing a program executable by a processor to perform actions including:

9. The action is creating a model of the bone intraoperatively after removal of the primary implant component from the bone; using the model to plan placement of a revision implant for the bone; The non-transitory computer-readable memory of claim 8 further comprising:

10. 10. The non-transitory computer-readable memory of claim 9, wherein the actions further include generating a control configured to provide a second constraint to the cutting tool while the cutting tool prepares the bone according to planned placement of the revision implant.

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