System and method for generating patient-specific milling paths

Abstract

A computer-implemented method is provided. The computer-implemented method generates a milling path for a tool of a surgical system, the milling path designed to enable the tool to resect material from a bone, the method including obtaining a model of the bone, intersecting an allowed volume with the model to define a resection volume intended to be removed from the bone, and generating a plurality of cross sections. The method further includes, for a cross section, identifying a sub-volume of the resection volume corresponding to the cross section, generating a milling path segment designed to enable the tool to remove the sub-volume of the resection volume, for the sub-volume of the resection volume, identifying a region to be avoided by the tool, generating a transition path segment designed to avoid the region, and generating the milling path by combining the milling path segment and the transition path segment.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and all benefits to U.S. Provisional Patent Application No. 63 / 547,902, filed November 9, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Surgical procedures require specialized tools to perform tasks demanding a high degree of accuracy and precision. These procedures necessitate precise positioning of tools and / or implants relative to the patient's anatomy. In orthopedic procedures, such as removing tissue within bone to create a cavity, success depends heavily on the surgeon's carefulness. Removing hard tissue, such as bone, to create a cavity without affecting adjacent soft tissue can be particularly challenging.

[0004] There is a need in the art to remove tissue to create a cavity in order to overcome one or more of the problems described above. Summary of the Invention

[0005] According to one aspect, a computer-implemented method is provided. The computer-implemented method generates a milling path for a tool for a surgical system, the milling path being designed to enable the tool to remove material from bone defining a socket for a joint, the computer-implemented method comprising: obtaining a model of the bone including the socket; intersecting the model of the socket with an allowable volume to define a resection volume intended to be removed from the bone; generating a plurality of cross sections; for at least one cross section: identifying a sub-volume corresponding to the cross section of the resection volume; generating one or more milling path segments designed to enable the tool to remove the sub-volume of the resection volume; identifying a region to be avoided by the tool for the sub-volume of the resection volume corresponding to the cross section; generating one or more transition path segments designed to avoid the region; and generating the milling path by combining the one or more milling path segments and the one or more transition path segments.

[0006] According to a second aspect, a non-transitory computer-readable medium is provided, the non-transitory computer-readable medium comprising instructions executable by one or more processors. The instructions implement software program for generating milling paths for a tool for a surgical system, the milling paths being designed to enable the tool to remove material from bone defining a socket for a joint, the software program being configured to: obtain a model of the bone including the socket; intersect the model of the socket with an allowable volume to define a resection volume intended to be removed from the bone; generate a plurality of cross sections; for at least one cross section: identify a sub-volume corresponding to the cross section of the resection volume; generate one or more milling path segments designed to enable the tool to remove the sub-volume of the resection volume; identify regions to be avoided by the tool for the sub-volume of the resection volume; generate one or more transition path segments designed to avoid the regions; and generate the milling path by combining the one or more milling path segments and the one or more transition path segments.

[0007] In a third aspect, a surgical system is provided. The surgical system includes: a manipulator comprising a robotic arm formed by a plurality of links and joints and supporting a tool; a control system configured to generate a milling path designed to enable the tool to remove material from bone defining a socket for a joint, wherein, in order to generate the milling path, the control system is configured to: obtain a model of the bone including the socket; intersect the model of the socket with an allowable volume to define a resection volume intended to be removed from the bone; generate a plurality of cross sections; for at least one cross section: identify a sub-volume corresponding to the cross section of the resection volume; generate one or more milling path segments designed to enable the tool to remove the sub-volume of the resection volume; identify regions to be avoided by the tool for the sub-volume of the resection volume; and generate one or more transition path segments designed to avoid the regions; and generate the milling path by combining the one or more milling path segments and the one or more transition path segments; wherein the control system is configured to control the manipulator to move the tool along the generated milling path.

[0008] According to a fourth aspect, a computer-implemented method is provided for generating milling paths for tools used in surgical systems. The milling paths are designed to enable the tool to remove material from bone defining a socket for a joint. The computer-implemented method includes: obtaining a model of the bone including the socket; intersecting the model of the socket with an allowable volume to define a resection volume intended to be removed from the bone, wherein the allowable volume defines a boundary with respect to the tool; and generating a first cross-section and a second cross-section, the first cross-section being adjacent to the second cross-section; wherein the distance between the first cross-section and the second cross-section is based on a residual height.

[0009] According to a fifth aspect, a computer-implemented method is provided for generating milling paths for a tool for a surgical system. The milling paths are designed to enable the tool to remove material from bone defining a socket for a joint. The computer-implemented method includes: obtaining a model of the bone including the socket; intersecting the model of the socket with an allowable volume to define a resection volume intended to be removed from the bone, wherein the allowable volume defines a boundary with respect to the tool; defining a retaining volume disposed within the allowable volume, wherein the retaining volume defines a boundary with respect to the tool, and wherein a distance is defined between the boundary of the retaining volume and the boundary of the allowable volume; generating a plurality of cross-sections; identifying sub-volumes of the resection volume for the plurality of cross-sections and generating a milling path designed to enable the tool to remove the sub-volumes of the resection volume; and generating a plurality of transition path segments for connecting milling paths of adjacent cross-sections, wherein the plurality of transition path segments extend along the boundary of the retaining volume between adjacent cross-sections and form a helix.

[0010] According to a sixth aspect, a computer-implemented method for generating a milling path for a tool for a system, the milling path being designed to enable the tool to remove material, the computer-implemented method comprising: obtaining a model of the material to be removed; intersecting an allowable volume with the model of the material to define a cut-off volume intended to be removed; generating a plurality of cross sections; for at least one cross section: identifying a sub-volume of the cut-off volume corresponding to the cross section; generating one or more milling path segments designed to enable the tool to remove the sub-volume of the cut-off volume; identifying a region to be avoided by the tool for the sub-volume of the cut-off volume; generating one or more transition path segments designed to avoid the region; and generating the milling path by combining the one or more milling path segments and the one or more transition path segments.

[0011] A non-transitory computer-readable medium (or computer program product) configured to implement any of the above aspects is also provided. A surgical system is also provided, the surgical system including a controller configured to implement any of the above aspects.

[0012] Any of the above aspects may be combined in part or in whole. Any or more of the above aspects may be combined in part or in whole with any or more of the following implementations.

[0013] In some implementations, the computer-implemented method further includes: generating a safeguard volume within the allowable volume, wherein the safeguard volume defines a boundary with respect to the tool, wherein the allowable volume defines a boundary with respect to the tool, wherein the boundary of the safeguard volume is spaced apart from the boundary of the allowable volume, and wherein one or more transition path segments are defined by the geometry of the safeguard volume. In some implementations, the computer-implemented method further includes: generating an internal allowable volume within the allowable volume, wherein the internal allowable volume defines a boundary with respect to the tool, wherein the boundary of the internal allowable volume is spaced apart from the boundary of the allowable volume, and wherein the safeguard volume is defined within the internal allowable volume, and the boundary of the safeguard volume is spaced apart from the internal allowable volume. In some implementations, the tool comprises a spherical cutting drill with a drilling radius, and wherein the boundary of the internal allowable volume is spaced apart from the boundary of the allowable volume by the drilling radius. In some implementations, the allowable volume extends along an axis. In some implementations, the allowable volume, the internal allowable volume, and the safeguard volume are coaxial about the axis. In some implementations, the allowable volume, the internal allowable volume, and the safeguard volume are each rotationally symmetric. In some implementations, the geometry of the allowable volume is based on the geometry of the implant to be inserted into the socket. In some implementations, the allowable volume includes a cylindrical portion having a first end and a second end along the axis, the first end and the second end defining the height of the cylindrical portion. In some implementations, the allowable volume includes a spherical crown portion having a center located on the axis, and wherein the spherical crown portion is integrated with the cylindrical portion and extends from the second end of the cylindrical portion.

[0014] In some implementations, the computer-implemented method further includes: identifying gap interruptions in the cut-off volume where the sub-volumes of the cut-off volume are defined by the absence of the cut-off volume, wherein the region to be avoided by the tool includes the gap. In some implementations, the computer-implemented method further includes: determining whether the size of the gap is greater than a threshold, and generating the one or more transition path segments in response to determining that the size of the gap is greater than the threshold.

[0015] In some implementations, the cross section is further defined as a sector extending radially from the axis toward the boundary of the allowable volume. In some implementations, the sector is defined perpendicular to the boundary of the allowable volume. In some implementations, the cross section is further defined as a first sector, wherein a cross section adjacent to the first cross section is further defined as a second sector, and wherein the sub-volume corresponding to the first sector that identifies the cut-off volume includes the sub-volume located between the first sector and the second sector that identifies the cut-off volume.

[0016] In some implementations, the one or more milling path segments are generated based on the intersection of the internal allowable volume and the cross-section. In some implementations, generating the one or more transition path segments includes generating one or more transition path segments for connecting the one or more milling path segments of the at least one cross-section, wherein the one or more transition path segments extend along the cross-section between the one or more milling path segments and the boundary of the protective volume. In some implementations, connecting transition path segments are generated for connecting milling path segments of a first cross-section and milling path segments of an adjacent second cross-section, wherein the connecting transition path segments extend along the boundary of the protective volume between the first cross-section and the adjacent second cross-section. In some implementations, the plurality of connecting transition path segments form a spiral extending along the boundary of the protective volume.

[0017] In some implementations, the skeleton is the pelvis or scapula. Attached Figure Description

[0018] The advantages of this disclosure will become readily apparent as they are considered with reference to the following detailed description and the accompanying drawings. Non-limiting and non-exhaustive embodiments of this disclosure are described with reference to the following drawings, wherein, unless otherwise stated, the same figures refer to the same parts in the various views.

[0019] Figure 1 It is a perspective view of a system used to manipulate the patient's anatomical structures.

[0020] Figure 2 Is it possible to... Figure 1The diagram shows a block diagram of the controller used in the system.

[0021] Figure 3 It is used to generate Figure 1 The flowchart shows the method for milling paths of the tools in the system shown.

[0022] Figure 4 It is a perspective view of the skeletal model.

[0023] Figure 5 It is by Figure 3 The method shown generates a perspective view of the boundary volume.

[0024] Figure 6 It is by Figure 3 A schematic diagram of the milling path generated by the method shown.

[0025] Figure 7A yes Figure 4 The model shown is the same as Figure 5 The perspective view showing the intersection of boundary volumes.

[0026] Figure 7B It is to be by Figure 3 A perspective view of the cut volume generated by the method shown.

[0027] Figure 8A It is a schematic diagram of multiple reference planes, where the first section and the second section correspond to the first reference plane and the second reference plane.

[0028] Figure 8B It is a schematic diagram of multiple points, where the first cross section and the second cross section correspond to the first point and the second point.

[0029] Figure 9A and Figure 9B Is it separate from Figure 7B The diagram shows the first and second cross sections where the cut-off volumes intersect.

[0030] Figure 10A This is a schematic diagram of multiple reference planes separated by step spacing.

[0031] Figure 10B and Figure 10C yes Figure 10A A schematic diagram of multiple reference planes, wherein the step distance separating the reference planes is calculated based on the desired residual height.

[0032] Figure 11A It is by Figure 3 The diagram shows the first and second sectors generated by the method shown.

[0033] Figure 11B It is by Figure 3The method shown generates a perspective view of the first and second sectors, as well as the cut sub-volume.

[0034] Figure 12A and Figure 12B It is used for excision Figure 11B A schematic diagram of the milling path for removing the sub-volume.

[0035] Figure 13 It is by Figure 3 The diagram shows a milling path segment generated by the method shown for cutting off the sub-volume.

[0036] Figure 14A and Figure 14B This is a schematic diagram of a transitional path segment used to avoid the removal of soft tissue.

[0037] Figure 15 and Figure 16 This is a schematic diagram of the alternative transition path segment.

[0038] Figure 17 This is a schematic diagram of the milling path for removing the cut volume.

[0039] Figure 18A and Figure 18B It is a perspective view of connecting transition path segments. Detailed Implementation

[0040] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention need not be practiced with respect to these specific details and / or not necessarily with respect to them entirely. In some instances, well-known materials or methods have not been described in detail to avoid obscuring the invention.

[0041] I. System Overview

[0042] Figure 1 This is a perspective view of a system 10 used to manipulate the anatomical structures of patient 12. More specifically, system 10 is a robotic surgical cutting system for cutting material such as bone or soft tissue from the anatomical structures of patient 12. Figure 1 In the middle, patient 12 is undergoing surgical procedures. Figure 1 The anatomical structures included in the image are the femur (F) and tibia (T) of patient 12. (Reference) Figure 4The anatomical structures also include the pelvis (P) and acetabulum (A). Surgical procedures may involve tissue removal and may also involve inserting one or more implants or grafts (e.g., bone or cartilage grafts, true ligaments, or artificial ligaments, etc.) into a portion of the patient's anatomy. In some embodiments, surgical procedures involve partial or total knee or hip replacement surgery. Some of these types of implants that can be used in surgical procedures are illustrated in U.S. Patent 9,381,085 entitled "Prosthetic Implant and Method of Implantation," the disclosure of which is hereby incorporated by reference. Those skilled in the art will understand that the systems and methods disclosed herein can be used to perform other procedures (surgical or non-surgical procedures) or for industrial applications or other applications utilizing robotic systems.

[0043] System 10 includes a surgical robot manipulator 14. Manipulator 14 has a base 16 and a linkage mechanism 18. Linkage mechanism 18 may include links forming a series or parallel arm configuration. An end effector 20 is removably coupled to manipulator 14 and movable relative to base 16 to interact with the surgical environment (more specifically, anatomical structures). End effector 20 is gripped by an operator. An exemplary arrangement of manipulator 14 and end effector 20 is described in U.S. Patent No. 9,119,655, entitled “Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes,” the disclosure of which is incorporated herein by reference. Alternative configurations of manipulator 14 and end effector 20 are possible. End effector 20 includes an energy applicator 24 designed to contact tissue of patient 12 at the surgical site. End effector 20 may have various configurations depending on the application. The energy applicator 24 can be a cavity-creating tool, such as a drill bit, saw blade, drill tip, ultrasonic vibrating tip, probe, stylus, reamer, file, impactor, etc. The manipulator 14 also houses a manipulator computer 26 or other type of control unit. The end effector 20 can be as shown in U.S. Patent 9,566,121 entitled "End Effector of a Surgical Robotic Manipulator," which is incorporated herein by reference.

[0044] refer to Figure 2System 10 includes a controller 30. The controller 30 includes software and / or hardware for controlling the manipulator 14. The controller 30 directs the movement of the manipulator 14 and controls the orientation of the end effector 20 relative to a coordinate system. In one embodiment, the coordinate system is the manipulator coordinate system MNPL (see [link to documentation]). Figure 1 The manipulator coordinate system MNPL has an origin, and the origin is located at a point on the manipulator 14. An example of the manipulator coordinate system MNPL is described in U.S. Patent No. 9,119,655 entitled “Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes,” the disclosure of which is hereby incorporated by reference.

[0045] System 10 also includes a navigation system 32. An example of the navigation system 32 and its associated components is described in U.S. Patent No. 9,008,757, filed September 24, 2013, entitled “Navigation System Including Optical and Non-Optical Sensors,” which is incorporated herein by reference. The navigation system 32 is designed to track the movement of various objects. Such objects include, for example, an end effector 20 and anatomical structures or portions thereof, such as the femur (F), tibia (T), and acetabulum (A). The navigation system 32 tracks these objects to collect positional information for each object in the locator coordinate system LCLZ. Conventional transformation techniques can be used to transform the coordinates in the locator coordinate system LCLZ to the manipulator coordinate system MNPL. The navigation system 32 is also capable of displaying a virtual representation of their relative positions and orientations to the operator.

[0046] The navigation system 32 includes a computer cart assembly 34 that houses a navigation computer 36 and / or other types of control units. A navigation interface operatively communicates with the navigation computer 36. The navigation interface includes one or more displays 38. A first input device 40 and a second input device 42, such as a keyboard and mouse or a touchscreen, can be used to input information into the navigation computer 36 or otherwise select / control certain features of the navigation computer 36. Other input devices 40, 42 are contemplated, including voice activation. The controller 30 may be implemented on one or more suitable devices in system 10, including but not limited to the manipulator computer 26, the navigation computer 36, and any combination thereof.

[0047] The navigation system 32 also includes a locator 44 that communicates with the navigation computer 36. In one embodiment, the locator 44 is an optical locator and includes a camera unit 46. The camera unit 46 has an outer housing 48 that houses one or more optical position sensors 50. The system 10 includes one or more trackers. Trackers may include a pointer tracker PT, a tool tracker 52, a first patient tracker 54, and a second patient tracker 56. Trackers include markers 58. The marker 58 may be a light-emitting diode or an LED. In other embodiments, the marker 58 is a passive marker, such as a reflector that reflects light emitted from the camera unit 46. Those skilled in the art will understand that other suitable tracking systems and methods not specifically described herein, such as electromagnetic positioning systems, ultrasound, etc., may be utilized.

[0048] exist Figure 1 In the illustrated embodiment, a first patient tracker 54 is securely attached to the femur F of patient 12, and a second patient tracker 56 is securely attached to the tibia T of patient 12 for use in, for example, knee replacement surgery. Alternatively, the first patient tracker 54 may be attached to the femur F of patient 12, and the second patient tracker 56 may be attached to the acetabulum A or pelvis P of patient 12 for use in hip replacement surgery. Patient trackers 54 and 56 are securely attached to the cross-section of the bone. Tool tracker 52 is securely attached to end effector 20. It should be understood that trackers 52, 54, and 56 can be secured to their respective components in any suitable manner.

[0049] Trackers 52, 54, and 56 communicate with camera unit 46 to provide position data to camera unit 46. Camera unit 46 provides the position data of trackers 52, 54, and 56 to navigation computer 36. In one embodiment where trackers 54 and 56 are coupled to the patient's femoral F and acetabular A, navigation computer 36 determines the position data of the femoral F and acetabular A, as well as the position data of the end effector 20, and transmits said position data to manipulator computer 26. Alternatively, navigation computer 36 may determine the position data of the tibia T or another part of the anatomical structure to which tracker 56 can be coupled, and may transmit the position data to manipulator computer 26. The position data of the femoral F, acetabular A, and end effector 20 may be determined from tracker position data using conventional registration / navigation techniques. Position data includes position information corresponding to the position and / or orientation of the femoral F, acetabular A, end effector 20, and any other tracked object. The position data described herein may be position data, orientation data, or a combination of position data and orientation data.

[0050] The manipulator computer 26 transforms position data from the locator coordinate system LCLZ to the manipulator coordinate system MNPL by determining a transformation matrix using navigation-based data and encoder-based position data from the end effector 20. An encoder (not shown) located at the joint of the manipulator 14 is used to determine the encoder-based position data. The manipulator computer 26 uses the encoder to calculate the encoder-based position and orientation of the end effector 20 in the manipulator coordinate system MNPL. Since the position and orientation of the end effector 20 are also known in the locator coordinate system LCLZ, the transformation matrix can be generated.

[0051] II. Software Module Overview

[0052] like Figure 2 As shown, controller 30 also includes a software module. The software module may be part of one or more computer programs that operate on the manipulator computer 26, navigation computer 36, or a combination thereof to process data to assist in the control of system 10. The software module includes an instruction set stored in memory on the manipulator computer 26, navigation computer 36, or a combination thereof for execution by one or more processors of computers 26, 36. Additionally, software modules for prompting and / or communicating with the operator may be part of one or more programs and may include instructions stored in memory on the manipulator computer 26, navigation computer 36, or a combination thereof. The operator interacts with a first input device 40 and a second input device 42, as well as one or more displays 38, to communicate with the software module.

[0053] like Figure 2 As shown, controller 30 may include manipulator controller 60. Manipulator controller 60 can process data to guide the movement of manipulator 14. Manipulator controller 60 can receive and process data from a single source or multiple sources.

[0054] The controller 30 may include a navigation controller 62 for transmitting position data relating to the femur F, acetabulum A (or other anatomical structures such as the tibia T), and end effector 20 to the manipulator controller 60. The manipulator controller 60 may receive and process the position data provided by the navigation controller 62 to guide the movement of the manipulator 14. In one embodiment, such as Figure 1 As shown, the navigation controller 62 is implemented on the navigation computer 36.

[0055] The manipulator controller 60 or navigation controller 62 can also communicate the position of the patient 12 and the end effector 20 to the operator by displaying images of anatomical structures (e.g., acetabulum A and / or femur F) and the end effector 20 on the display 38. The manipulator computer 26 or navigation computer 36 can also display instructions or request information on the display 38, allowing the operator to interact with the manipulator computer 26 to guide the manipulator 14.

[0056] like Figure 2 As shown, controller 30 includes boundary generator 66. Boundary generator 66 generates the boundaries of end effector 20. For example, refer to... Figure 5 Boundary generator 66 can generate a boundary volume BV. The boundary volume BV may include an allowable volume AV, an internal allowable volume IAV, and a safeguard volume SV. The allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV each define the boundary of the end effector 20, which will be described in more detail below. Boundary generator 66 is a software module that can be implemented on the manipulator controller 60, such as... Figure 2 As shown. Alternatively, the boundary generator 66 can be implemented on other components such as the navigation controller 62.

[0057] like Figure 2 As shown, controller 30 includes tool path generator 69. (See reference) Figure 6 The tool path generator 69 can be configured to generate a milling path MP for the end effector 20 to move along. The tool path generator 69 is a software module that can be implemented on the manipulator controller 60, such as... Figure 2 As shown. Alternatively, the tool path generator 69 can be implemented on other components such as the navigation controller 62.

[0058] III. Generate patient-specific milling paths

[0059] Figure 3 A method 1000 is illustrated for generating a patient-specific milling path MP for an end effector 20, the milling path MP being designed to enable the end effector 20 to remove material from bone defining a socket for a joint. In the example illustrated herein, method 1000 generates a milling path MP for total hip arthroplasty. Figure 6 An example milling path MP is shown, wherein the milling path MP is designed such that the center of the end effector 20 moves along it so that the end effector 20 can remove material from the pelvic P (bone) defining the acetabulum A (socket) for the hip joint. More specifically, as the end effector 20 travels along the milling path MP, the end effector 20 removes material from the acetabulum A to prepare the acetabulum A for placement of an implant therein.

[0060] In other instances, method 1000 can generate milling paths MP for other types of surgical procedures. For example, method 1000 can generate milling paths MP for shoulder replacement surgery. Specifically, milling paths MP can be generated to remove material from the scapula, which defines a glenoid fossa for the shoulder joint. In another example, method 1000 can generate milling paths MP for knee replacement surgery.

[0061] As described herein, method 1000 can be performed before or during the procedure. For example, method 1000 can be performed before the procedure, such that method 1000 generates the milling path MP before the surgical procedure is performed. Method 1000 can also be performed while the surgical procedure is being performed, so that the milling path MP can be generated on the fly.

[0062] i. Obtaining a model of hard tissue

[0063] like Figure 3 As shown, method 1000 includes obtaining a model 70 of hard tissue, such as... Figure 4 Step 1002 of the model 70 shown. Step 1002 can be executed by any suitable software module of the controller 30. For example, the manipulator controller 60 or the navigation controller 62 can obtain the hard tissue model 70. The model 70 can be obtained using any suitable imaging modality. For example, the model 70 can be obtained by MRI, CT scan, ultrasound, X-ray, etc.

[0064] Generally, model 70 indicates the hard tissue to be removed by end effector 20. For example, model 70 could be a model of bone including the axilla. Figure 4 In one example, model 70 includes the pelvis P that defines the acetabulum A.

[0065] Soft tissue can be omitted from such a model 70. For example, soft tissue may exist in areas where the presence of hard tissue is not indicated in model 70. Therefore, method 1000 generates a milling path MP to remove the hard tissue indicated by model 70 and avoid the soft tissue. (See reference) Figure 6 The milling path MP may include a milling path segment MPS and a transition segment TS. As will be explained in more detail below, the end effector 20 moves along the milling path segment MPS to remove material from the acetabulum A; and the end effector 20 moves along the transition segment TS to avoid the removal of soft tissue.

[0066] Additionally, model 70 can be a patient-specific model representing the hard tissue of the patient to be operated on. As follows, the milling path MP generated to remove the hard tissue exemplified by model 70 can be considered a patient-specific milling path MP.

[0067] ii. Generate boundary volume

[0068] refer to Figure 3 Method 1000 further includes step 1004 of generating the allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV of the boundary volume BV. Figure 5 The allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV are shown. As previously described, the boundary generator 66 can perform step 1004 and generate the allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV.

[0069] refer to Figure 5 The internal allowable volume IAV and the safeguard volume SV are generated within the allowable volume AV. More specifically, the safeguard volume SV is generated within the internal allowable volume IAV, which in turn is generated within the allowable volume AV. Although the internal allowable volume IAV and the safeguard volume SV are generated within the allowable volume AV, they may not be entirely encapsulated by the allowable volume AV. Similarly, although the safeguard volume SV is generated within the internal allowable volume IAV, it may not be entirely encapsulated by the internal allowable volume IAV.

[0070] The volume AV is allowed to extend along the axis AX. Figure 5 In one example, the allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV each extend along and are coaxial around the axis AX. In other examples, the allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV may not be coaxial. For example, the allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV may each extend along different axes. Additionally, in Figure 5 In the example, the allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV are each rotationally symmetric about the axis AX. In other examples, the allowable volume AV, the internal allowable volume IAV, and the safeguard volume SV may be rotationally asymmetric.

[0071] The permissible volume AV, the internal permissible volume IAV, and the guaranteed volume SV each define boundaries for the end effector 20. For example... Figure 6 As shown, the allowable volume AV defines a boundary 72 for the surface of the end effector 20, such that when the end effector 20 travels along the milling path MP, the surface of the end effector 20 does not exceed the boundary 72 of the allowable volume AV. The internal allowable volume IAV and the safeguard volume SV define boundaries 74 and 76 respectively for the center of the end effector 20. Figure 6 As shown, boundaries 74 and 76 are defined such that when the end effector 20 travels along the transition section TS, the center of the end effector 20 is restricted between boundaries 74 and 76, such that the center of the end effector 20 does not exceed boundaries 74 and 76.

[0072] like Figure 6As shown, the boundary 74 of the inner permissible volume IAV is spaced apart from the boundary 72 of the permissible volume AV. Specifically, the boundary 74 of the inner permissible volume IAV is spaced apart from the boundary 72 of the permissible volume AV by a distance d. In an example where the end effector 20 includes a spherical cutting drill with a drill radius, the distance d may correspond to the drill radius. For example, the distance d may be equal to the drill radius. In such an example, as the end effector 20 travels along the milling path segment MPS, the center of the end effector 20 is confined to the boundary 74 of the inner permissible volume IAV, such that the surface of the end effector 20 does not exceed the boundary 72 of the permissible volume AV, and material is removed from the acetabulum A located within the boundary 72 of the permissible volume AV.

[0073] like Figure 6 As shown, the boundary 76 of the safeguard volume SV is spaced apart from the boundary 72 of the allowable volume AV. The safeguard volume SV can be spaced apart from the boundary 72 of the allowable volume AV such that when the end effector 20 travels along the transition path segment TPS, the center of the end effector 20 is positioned between the inner allowable volume IAV and the safeguard volume SV to avoid the removal of soft tissue.

[0074] The allowable volume AV, internal allowable volume IAV, and safeguard volume SV can include any suitable shape. For example, the geometry of the allowable volume AV and / or internal allowable volume IAV can be based on the geometry of the implant to be inserted into the socket of bone (such as the acetabulum A of the pelvis P). As another example, the geometry of the safeguard volume SV can be based on the volume within the socket of bone where soft tissue is not typically present. For example, the geometry of the safeguard volume SV can be based on the volume within the acetabulum A where soft tissue is not typically present.

[0075] exist Figure 5 In this example, each of the volume AV and the internal volume IAV is allowed to include a cylindrical volume and a spherical volume. Specifically, the volume AV and the internal volume IAV are allowed to include cylindrical portions 78 and 80 and spherical cap portions 82 and 84. Figure 5 As shown, the cylindrical portion 78 allowing volume AV includes a first end 86 and a second end 88 along the axis AX, wherein the first end and the second end define a height h1 of the cylindrical portion 78. Figure 5 In one example, the cap portion 82 of the allowable volume AV is hemispherical. It is also shown that the cylindrical portion 80 of the internal allowable volume IAV includes a first end 90 and a second end 92 along the axis AX, wherein the first and second ends define a height h2 of the cylindrical portion 80. Figure 5 In the example, the spherical cap portion 84 of the internal allowable volume IAV is a hemisphere.

[0076] In other instances, the allowable volume AV and the internal allowable volume IAV may include alternative geometries. For example, the allowable volume AV and the internal allowable volume IAV may include teardrop-shaped volumes and / or conical volumes. In one such example, the allowable volume AV and the internal allowable volume IAV may each include a conical portion located between the respective cylindrical portions 78, 80 and the spherical cap portions 82, 84. Furthermore, in other instances, the allowable volume AV and the internal allowable volume IAV may include different geometries. For example, the allowable volume AV may include a teardrop-shaped volume, and the internal allowable volume IAV may include a cylindrical volume only.

[0077] exist Figure 5 In one example, the safeguard volume SV comprises a teardrop-shaped volume. As shown, the teardrop-shaped volume extends along the axis AX, wherein the safeguard volume SV includes a spherical portion 94 that tapers to point 96. In other examples, the safeguard volume SV may include alternative geometries. For example, the safeguard volume SV may include a conical volume, a spherical volume, and / or a cylindrical volume.

[0078] iii. Define the volume to be removed

[0079] refer to Figure 3 Method 1000 includes step 1006 of intersecting the allowable volume AV with the model 70 of the socket to define a resection volume intended to be removed from the bone using a milling path MP. Figure 7A and Figure 7B An example of step 1006 is shown. As illustrated, the volume AV is allowed to intersect with the model 70 of the acetabulum A in order to define the volume to be drawn from the acetabulum A. Figure 7A The resection volume RV of the pelvic P is removed. Figure 7B The excised volume RV is further shown.

[0080] As described above, soft tissue can be omitted from model 70. Therefore, the resection volume RV typically corresponds to the hard tissue intended to be removed by the end effector 20. Figure 7A and Figure 7B In this example, the excised volume RV corresponds to the material to be removed from the acetabulum A.

[0081] iv. Generate multiple reference planes intersecting the excised volume.

[0082] refer to Figure 3 Method 1000 includes step 1008 of generating multiple reference planes. For example... Figure 8A As shown, the reference plane RP can divide the allowable volume AV. Specifically, the reference plane RP can intersect with the boundary 72 of the allowable volume AV to divide the allowable volume AV. Figure 8A In the example, a first exemplary reference plane RP1 and a second exemplary reference plane RP2 are shown.

[0083] Method 1000 may include step 1010 of generating multiple cross sections corresponding to multiple reference planes RP. Figure 8A Examples of multiple cross-sections S are shown. Specifically, in Figure 8A In the example, a first exemplary section S1 corresponding to a first exemplary reference plane RP1 and a second exemplary section S2 corresponding to a second exemplary reference plane RP2 are shown.

[0084] Multiple sections S are generated to identify the cut sub-volumes RSV of the cut volume RV. For example, in Figure 9A and Figure 9B In this process, a first exemplary section S1 and a second exemplary section S2 are generated to identify the first exemplary cut sub-volume RSV1 and the second exemplary cut sub-volume RSV2, respectively. Figure 9A and Figure 9B In one example, the first exemplary section S1 and the second exemplary section S2 intersect the cut-off volume RV to identify the first exemplary cut-off sub-volume RSV1 and the second exemplary cut-off sub-volume RSV2, respectively. In other examples, the identified cut-off sub-volume RSV may be adjacent to section S among a plurality of sections S.

[0085] Method 1000 generates a milling path MP for cutting the cut volume RV by generating a sub-volume milling path MPSV for cutting each cut sub-volume RSV. Figure 9A In this process, a first sub-volume milling path MPSV1 is generated to cut the first cut sub-volume RSV1. Figure 9B In the process, a second sub-volume milling path MPSV2 is generated to cut the second cut sub-volume RSV2. Once the end effector 20 has moved along the first sub-volume milling path MPSV1 and has cut the first cut sub-volume RSV1, the end effector 20 can advance to the second sub-volume milling path MPSV2 to cut the second cut sub-volume RSV2. Figure 9A and Figure 9B This document provides examples of subvolume cut volume (RSV) and subvolume milling path (MPSV). The steps for identifying the subvolume cut volume (RSV) and generating the subvolume milling path (MPSV) will be explained in more detail below.

[0086] Figure 10A An example of multiple reference planes RP is shown. As illustrated, the multiple reference planes RP are perpendicular to the axis AX and parallel to each other. Furthermore, adjacent reference planes RP are separated by a step size SD. In some instances, the step size SD can be a constant distance. In other instances, the step size SD can be a variable distance. For example, in... Figure 10A In this example, the step size SD is a variable distance based on the geometry that allows for the volume AV. For example, as... Figure 10AAs shown, the step distance SD-CYL between adjacent reference planes RP intersecting the cylindrical portion 78 of the allowable volume AV is greater than the step distance SD-SPH between adjacent reference planes RP intersecting the spherical cap portion 82 of the allowable volume AV.

[0087] The step size SD can be calculated based on the expected residual height SH between adjacent reference planes RP. The expected residual height SH corresponds to the expected height of hard tissue retained between adjacent resected subvolumes RSV after they have been removed. For example, the step size SD can be calculated such that the expected residual height SH is the expected minimum acceptable height, the expected maximum acceptable height, and / or the expected acceptable height of the reference planes RP with the minimum allowable number.

[0088] Figure 10B and Figure 10C An example calculation of step distance SD based on preserving the desired residual height SH is shown. Figure 10B The diagram shows reference planes RP intersecting the cylindrical portion 78 of the allowable volume AV, with a first reference plane RP1' and a second reference plane RP2' identified. The first reference plane RP1' intersects the boundary 72 of the allowable volume AV at a first intersection point P1'. The second reference plane RP2' intersects the boundary 72 of the allowable volume AV at a second intersection point P2'. Figure 10C The diagram shows reference planes RP intersecting the spherical cap portion 82 of the allowable volume AV, where first reference plane RP1'', second reference plane RP2'', and third reference plane RP3'' are identified. First reference plane RP1'' intersects the boundary 72 of the allowable volume AV at the first intersection point P1''. Second reference plane RP2'' intersects the boundary 72 of the allowable volume AV at the second intersection point P2''. Third reference plane RP3'' intersects the boundary 72 of the allowable volume AV at the third intersection point P3''. As shown, the step distance SD-CYL between adjacent reference planes RP intersecting the cylindrical portion 78 and the step distance SD-SPH between adjacent reference planes RP intersecting the spherical cap portion 82 are calculated based on the desired residual height SH.

[0089] The residual height SH depends on the geometry of the end effector 20. Geometrically, the residual height SH is defined as the distance from the boundary 72 of the allowable volume AV to the residual points SP', SP''. The location of the residual points SP', SP'' is defined by the geometry of the end effector 20. For illustration, the representation of the end effector 20' is superimposed on the allowable volume AV, where the representation of the end effector 20' is at the intersection point between the reference plane RP and the boundary 72 (i.e., Figure 10B and Figure 10CThe intersection points P1', P1'', P2', P2'') are tangent to boundary 72. Residual points SP', SP'' are defined as being located at the intersection of adjacent representations of the end effector 20', wherein residual points SP', SP'' are located at a common distance CD from the first intersection point P1', P1'' and the second intersection point P2', P2''. As should be understood from the above description, if the geometry of the end effector 20 is... Figure 10B and Figure 10C If the geometry shown is different, the step distance SD between multiple reference planes RP will also be different.

[0090] The step distance SD-CYL between adjacent reference planes RP intersecting the cylindrical portion 78 and the step distance SD-SPH between adjacent reference planes RP intersecting the spherical cap portion 82 are calculated to preserve the desired residual height SH. Figure 10B In this process, the step size SD-CYL is calculated to be the same between any two reference planes RP to preserve the desired residual height SH. Figure 10C In this calculation, the step size SD-SPH is calculated to be variable between reference planes RP to preserve the desired residual height SH. For example, the step size SD-SPH1 between reference planes RP1'' and RP2'' is greater than the step size SD-SPH2 between reference planes RP2'' and RP3''.

[0091] The desired residual height SH can be selected based on the desired height of hard tissue remaining between adjacent resected sub-volumes RSV after they have been removed. Furthermore, the desired residual height SH is geometrically defined as the distance from the boundary 72 of the allowable volume AV to the residual points SP', SP''. Therefore, the desired height of hard tissue remaining between adjacent resected sub-volumes RSV is greater than... Figure 10B and Figure 10C In an example of residual height SH, the positioning of the end effector 20' can be spaced further apart, making the residual points SP', SP'' farther away from the boundary 72 of the allowable volume AV. As follows, since the representation of the end effector 20' is defined to be tangent to the boundary 72 at the intersection point between the reference plane RP and the boundary 72, the reference planes RP can also be spaced further apart, and the step size SD can be larger. Similarly, in cases where the desired height of hard tissue held between adjacent excised sub-volumes RSV is less than... Figure 10B and Figure 10C In the example of residual height SH, the positions of the end effectors 20' can be closer to each other, so that the residual points SP', SP'' are closer to the boundary 72 of the allowable volume AV. As such, the reference planes RP can also be closer to each other, and the step distance SD can be smaller.

[0092] Therefore, since adjacent reference planes RP can be separated by step spacing SD, corresponding adjacent sections S among multiple sections S can also be separated by step spacing SD. For example, in instances where section S is coplanar with the corresponding reference plane RP (such as... Figure 8A In an example, adjacent sections S can also be separated by a step distance SD. As another example, in an instance where one or more sections in adjacent sections S include non-planar geometry, a point on the first section S can be separated from a point on the adjacent section S by a step distance SD.

[0093] In various instances of the method, aspects of the multiple reference planes RP may differ. In some instances, the orientation of the reference planes RP relative to the axis AX may differ. Figure 10A In one example, multiple reference planes RP are oriented such that RP is perpendicular to the axis AX. However, in other examples, multiple reference planes RP may be oriented such that RP is not perpendicular to the axis AX. Multiple reference planes RP may also be oriented such that they are not parallel to each other. In some examples, the distances between the reference planes RP may be different. For example... Figure 10A As shown, adjacent reference planes RP are separated by a step size SD. In some instances, the step size SD can be a constant distance. In other instances, the step size SD can be a variable distance. For example, in... Figure 10A In this example, the step size SD is a variable distance based on the geometry that allows for the volume AV. For example, as... Figure 10A As shown, the step distance SD-CYL between the reference planes RP of the cylindrical portion 78 adjacent to the allowable volume AV is greater than the step distance SD-SPH between the reference planes RP of the spherical cap portion 82 adjacent to the allowable volume AV.

[0094] In some instances, method 1000 may optionally omit the generation of multiple reference planes RP. For example, in Figure 8B In an example, method 1000 alternatively generates multiple points P along the boundary 72 of the allowed volume AV, such as a first exemplary point P1 and a second exemplary point P2. Figure 8BIn this example, points P are generated along boundary 72 such that the projection P_PROJ of each point in P along the axis AX has a unique location. As an example, the first projection point P1_PROJ corresponds to the first exemplary point P1 and is defined as the projection of the first exemplary point P1 along the axis AX; and the second projection point P2_PROJ corresponds to the second exemplary point P2 and is defined as the projection of the second exemplary point P2 along the axis AX. As shown, the location of projection point P1_PROJ along the axis AX is different from the location of the second projection point P2_PROJ along the axis AX. In this example, each of the plurality of points P corresponds to a section S in the plurality of sections S. For example, the first exemplary point P1 corresponds to the first exemplary section S1, and the second exemplary point P2 corresponds to the second exemplary section S2.

[0095] v. Generate multiple cross-sections corresponding to the reference plane.

[0096] As discussed above, method 1000 includes the step of generating multiple cross sections S corresponding to multiple reference planes RP. The multiple cross sections S can include any suitable geometry. For example, Figure 8A The multiple cross sections S shown include planar geometry. Figure 11A and Figure 11B Additional examples of multiple cross sections S are shown, wherein the multiple cross sections S include non-planar geometries. In such examples, the multiple cross sections S may be further defined as multiple sectors SCTs, each sector SCT including a non-planar geometries. The multiple cross sections S may have a combination of cross sections S including planar geometries and sector SCTs including non-planar geometries. For example, the multiple cross sections S may have only cross sections S including planar geometries or at least one sector SCT including a non-planar geometries. In this document, when a cross section S includes a non-planar geometries, the cross section S may be referred to as a sector SCT.

[0097] exist Figure 11A and Figure 11B In one example, method 1000 generates a plurality of sector SCTs during step 1010, the plurality of sectors corresponding to each reference plane RP during step 1010. The sector SCT is defined to extend radially from axis AX toward boundary 72 of allowable volume AV, wherein the sector SCT is defined perpendicular to boundary 72 at the intersection of reference plane RP and boundary 72. For example, reference... Figure 11A A first sector SCT1, perpendicular to the boundary, is generated at the intersection of the first reference plane RP1 and the boundary 72, and a second sector SCT2, perpendicular to the boundary 72, is generated at the intersection of the second reference plane RP2 and the boundary 72. Figure 11AIn the example, the first sector SCT1 and the second sector SCT2 are shown in two dimensions to illustrate the angular relationship between the first sector SCT1 and the second sector SCT2 and the boundary 72. (See reference...) Figure 11B The first sector SCT1 and the second sector SCT2 are shown as three-dimensional objects.

[0098] vi. Generate subvolume milling path

[0099] Figure 3 Steps 1012-1020 shown are used to generate a sub-volume milling path MPSV for a single cross-section S. As previously described, method 1000 generates a milling path MP for cutting the cut volume RV by generating a sub-volume milling path MPSV for cutting the cut sub-volume RSV corresponding to the cross-section S. Steps 1012-1020 can be repeated and can be generated for any suitable number of cross-sections S (such as for each of a plurality of cross-sections S, for every other cross-section S of a plurality of cross-sections S, or for more than one cross-section S of a plurality of cross-sections S). In an instance of generating several sub-volume milling paths MPSV, the sub-volume milling paths MPSV together form a milling path MP. In an instance of generating a single sub-volume milling path MPSV, the single sub-volume milling path MPSV is a milling path MP.

[0100] a. Identify the volume of the excised sub-section

[0101] refer to Figure 3 In step 1012, method 1000 identifies the cut sub-volume RSV corresponding to the cross section S of the cut volume RV. Figure 11A and Figure 11B An example is shown where the excised sub-volume RSV is located at the spherical cap portion 82 adjacent to the permissible volume AV. Figure 11A and Figure 11B In the example, the section S is further defined as a sector SCT comprising a non-planar geometry. The excised sub-volume RSV is... Figure 11B The portion of the data identified as the cut volume RV located between the first sector SCT1 and the second sector SCT2, wherein the identified cut sub-volume RSV corresponds to either the first sector SCT1 or the second sector SCT2.

[0102] exist Figure 11A and Figure 11B In one example, the cut-off sub-volume RSV of the spherical cap portion 82 adjacent to the allowable volume AV is identified. In other examples, step 1012 (as described above) can be used to identify the cut-off sub-volume RSV of any other portion of the allowable volume AV, such as the cylindrical portion 78. Additionally, step 1012 (as described above) can be used to identify the cut-off sub-volume RSV of portions of different geometries adjacent to the allowable volume AV.

[0103] In some instances, method 1000 can identify the cut sub-volume RSV without generating two adjacent cross sections S or sectors SCTs. For example, in some instances, method 1000 can identify the cut sub-volume RSV during step 1012 as a sub-volume of the cut volume RV located between a single sector SCT and a step size SD above or below the single sector SCT. As another example, in some instances, method 1000 can identify the cut sub-volume RSV during step 1012 as a sub-volume of the cut volume RV located between a half-step size SD above a single sector SCT and a half-step size SD below a single sector SCT.

[0104] b. Generate milling path segments

[0105] refer to Figure 3 Method 1000 includes the step of generating one or more milling path segments MPS designed to enable the end effector 20 to remove a cut sub-volume RSV of a cut volume RV. The milling path segment MPS may be defined as a portion of a sub-volume milling path MPSV, along which the end effector 20 moves to cut the cut sub-volume RSV.

[0106] Figure 12A and Figure 12B An example milling path segment MPS is shown. (Example...) Figure 12A and Figure 12B As shown, the milling path segment MPS is generated such that when the end effector 20 moves along the milling path segment MPS, the end effector 20 removes the cut sub-volume RSV. The milling path segment MPS is generated based on the geometry of the internal allowable volume IAV and the intersection of the internal allowable volume IAV and the cross section S. Figure 12A The diagram shows a top view of the cut sub-volume RSV and the internal allowable volume IAV to illustrate that the milling path segment MPS is generated based on the geometry of the internal allowable volume IAV. The internal allowable volume IAV includes a circular cross-sectional shape, and therefore, the milling path segment MPS also includes a circular shape. Additionally, Figure 12A The milling path segment MPS is generated along the boundary 74 of the internal allowable volume IAV. Figure 12B The diagram further illustrates that the milling path segment MPS is generated along boundary 74 at the intersection of boundary 74 and the second sector SCT2. In an alternative example, the milling path segment MPS may be generated at the intersection of boundary 74 of the internal allowable volume IAV and the first sector SCT1.

[0107] exist Figure 12A and Figure 12BIn some instances, a single milling path segment (MPS) is generated to remove the cut sub-volume (RSV). In such instances, the sub-volume milling path (MPSV) comprises a single milling path segment (MPS). However, in other instances, more than one milling path segment (MPS) may be generated to remove the cut sub-volume (RSV). Figure 13 In one example, the subvolume milling path MPSV includes a first milling path segment MPS1 for cutting a first portion of the cut subvolume RSV1 and a second milling path segment MPS2 for cutting a second and a third portion of the cut subvolume RSV2, RSV3. In other examples, any suitable number of milling path segments MPS can be generated to cut the cut subvolume RSV.

[0108] c. Generate transition path segments

[0109] Method 1000 further includes the step of identifying regions to be avoided by the end effector 20 for the excised sub-volume RSV, and the step of generating one or more transition path segments TPS designed to avoid said regions. As previously described, the end effector 20 moves along the transition path segments TPS to avoid the excision of soft tissue. The transition path segment TPS may be defined as a portion of the sub-volume milling path MPSV, along which the end effector 20 moves to avoid the excision of soft tissue.

[0110] As previously stated, soft tissue can be omitted from model 70. For example, soft tissue may exist in areas where the presence of hard tissue is not indicated in model 70. In other words, soft tissue may be present in areas where the resection volume RV is absent. Areas where soft tissue may exist can be identified as areas to be avoided by end effector 20, and transition path segments TPS can be generated to avoid said areas. Thus, during step 1016, method 1000 can identify areas R to be avoided by end effector 20 by identifying gaps G interruptions where the resection sub-volume RSV is defined by the absence of the resection volume RV, wherein the area R to be avoided by end effector 20 includes gap G. For example, refer to Figure 14A and Figure 14B In this example, region R is the region to be avoided by the end effector 20 because region R includes gap G and gap G interrupts the cut-off subvolume RSV.

[0111] During step 1018, method 1000 generates one or more transition path segments (TPS) designed to avoid areas to be avoided by the end effector 20. For example, refer to Figure 14A and Figure 14BIn an example, method 1000 generates a transition path segment TPS to avoid the region R, which includes the gap G. Additionally, method 1000 generates one or more transition path segments TPS such that the one or more transition path segments TPS connect one or more milling path segments MPS of section S. For example... Figure 14A and Figure 14B As shown, the transition path segment TPS connects the first end 98 and the second end 99 of the milling path segment MPS.

[0112] One or more transition path segments TPS can be generated based on the geometry of the internal allowable volume IAV and extend along the boundary 76 of the guaranteed volume SV. Figure 14A A top view of the cut sub-volume RSV and the internal allowable volume IAV is shown to illustrate that the transition path segment TPS is generated based on the geometry of the safeguard volume SV. The safeguard volume SV has a circular cross-sectional shape, and therefore, the transition path segment TPS includes a portion extending along boundary 76, wherein the transition path segment TPS also includes a circular shape. One or more transition path segments TPS can also be generated as extending along sector SCT between one or more milling path segments MPS and the boundary 76 of the safeguard volume SV. Figure 14B An example transition path segment TPS includes a portion extending along the second sector SCT2 between the milling path segment MPS and the boundary 76. In an alternative example, the transition path segment TPS may be generated as extending along the first sector SCT1 between the milling path segment MPS and the boundary 76.

[0113] exist Figure 14A and Figure 14B In some instances, a single transition path segment (TPS) is generated to avoid the cut-off region R. In such instances, the subvolume milling path (MPSV) comprises a single transition path segment (TPS). However, in other instances, more than one transition path segment (TPS) may be generated to avoid more than one region R. Figure 13 In one example, the subvolume milling path MPSV includes a first transition path segment TPS1 for avoiding a first region R1 including a first gap G1, and a second transition path segment TPS2 for avoiding a second region R2 including a second gap G2. In other examples, any suitable number of milling path segments MPS can be generated to avoid any number of regions R.

[0114] In some instances, method 1000 may optionally omit the generation of the transition path segment TPS for avoiding the region R including the gap G.

[0115] In one such instance, method 1000 may include the step of determining whether the size of the gap G is greater than a threshold before generating a transition path segment TPS for avoiding the region R including the gap G. The threshold may be selected based on the probability that soft tissue is present in the region R where the resection volume RV is not present. For example, in an instance where the region R includes the gap G, the threshold may be a predetermined gap threshold size, and the predetermined gap threshold size may be selected such that if the size of the gap G is greater than the predetermined gap threshold size, the probability of soft tissue being present in the region R is higher. Similarly, the predetermined gap threshold size may be selected such that if the size of the gap G is less than the predetermined gap threshold size, the probability of soft tissue being present in the region R is lower.

[0116] In another such instance, if the excised subvolume is interrupted by a single gap, method 1000 may optionally omit the generation of the transition path segment TPS for avoiding the region R including the gap G. For example, refer to Figure 12A The cut sub-volume RSV is interrupted by a single gap G. In this instance, method 1000 may optionally omit the generation of the transition path segment TPS. Instead, once the end effector 20 has moved along the milling path segment MPS, method 1000 may proceed directly to the different sub-volume milling paths MPSV corresponding to different sections S.

[0117] Figure 13 Example 1000 omits the generation of transition path segment TPS in response to determining that the gap G in region R is less than a predetermined gap threshold size. As shown, the first gap G1 of the first region R1 can be defined as the region between the first and second portions of the excised sub-volumes RSV1 and RSV2; the second gap G2 of the second region R2 can be defined as the region between the third and first portions of the excised sub-volumes RSV3 and RSV1; and the third gap G3 of the third region R3 can be defined as the region between the second and third portions of the excised sub-volumes RSV2 and RSV3. As shown, the size of the first gap G1 and the second gap G2 is larger than the size of the third gap G3. Figure 13 In this example, method 1000 determines that the first gap G1 is greater than a predetermined gap threshold size, and therefore generates a first transition path segment TPS1 to avoid the first region R1. Method 1000 also determines that the second gap G2 is greater than the predetermined gap threshold size, and therefore generates a second transition path segment TPS2 to avoid the second region R2. However, method 1000 determines that the third gap G3 is not greater than the predetermined gap threshold size, and therefore does not generate a transition path segment TPS to avoid the third region R3.

[0118] exist Figure 13 , Figure 14A and Figure 14BIn the example, the transition path segment TPS is generated such that the transition path segment TPS connects one or more milling path segments MPS by advancing sharply from the milling path segment MPS toward the boundary 76 of the guarantee volume SV. In other instances (such as...) Figure 15 and Figure 16 In the example), the transition path segment TPS is generated to connect one or more milling path segments MPS by smoothly advancing from the milling path segment MPS toward the boundary 76 of the guarantee volume SV.

[0119] The transition path segment TPS of the sub-volume milling path MPSV can be generated to advance symmetrically and asymmetrically between boundary 76 and the milling path segment MPS of the sub-volume milling path MPSV, respectively. For example... Figure 15 As shown, the first sub-volume milling path MPSV1 includes a first milling path MPS1 and a second milling path MPS2, as well as a first transition path segment TPS1 and a second transition path segment TPS2; and the second sub-volume milling path MPSV2 includes the first milling path MPS1 and the second milling path MPS2, as well as a first transition path segment TPS1' and a second transition path segment TPS2'. For the first sub-volume milling path MPSV1, the portion P1 of the first transition path segment TPS1 advancing from the boundary 76 toward the second milling path MPS2 is symmetrical to the portion P2 of the second transition path segment TPS2 advancing from the second milling path MPS2 toward the boundary 76, wherein the symmetry is defined relative to the straight line L extending from the axis AX to the center C of the second milling path MPS2. For the second subvolume milling path MPSV2, the portion P1' of the first transition path segment TPS1' advancing from boundary 76 toward the second milling path MPS2 is symmetrical to the portion P2' of the second transition path segment TPS2' advancing from the second milling path MPS2 toward boundary 76, wherein the symmetry is defined relative to the straight line L extending from axis AX to the center C of the second milling path MPS2. In some instances, it may be advantageous for the transition path segment TPS to advance symmetrically or asymmetrically between boundary 76 and the milling path segment MPS. For example, symmetrical advancement of the transition path segment TPS may help avoid the removal of soft tissue. Asymmetrical advancement of the transition path segment TPS may help optimize the transition path segment TPS, as will be described in more detail below.

[0120] The transition path segment TPS of the sub-volume milling path (MPSV) can be optimized based on several parameters to minimize the cutting time of the end effector 20. For example, the transition path segment TPS can be optimized to minimize the distance traveled by the end effector 20, and the transition path segment TPS can be optimized to achieve maximum smoothness. This optimization can be useful in reducing the time spent by the end effector 20 performing air cutting when it is not removing material. In addition, this optimization reduces the number of sharp turns that the end effector 20 makes while traveling along the sub-volume milling path (MPSV). Since sharp turns can leave marks on the bone, this optimization allows the end effector 20 to smoothly remove the cut sub-volume (RSV).

[0121] For example, in Figure 15 In this example, the transition path segment TPS is optimized. Specifically, since the transition path segments TPS1' and TPS2' advance asymmetrically, the distance traveled by the end effector 20 when traveling along the transition path segments TPS1' and TPS2' is minimized.

[0122] As another example, the transition path segment TPS in Figure 16 Optimized in instances of [specific type of service]. See reference. Figure 16 The sub-volume milling path MPSV includes a transition path segment TPS, which connects the first end 98 and the second end 99 of the milling path segment MPS. Figure 16 In the example, the transition path segment TPS is optimized such that the distance traveled by the end effector 20 when traveling along the transition path segment TPS is minimized, and the transition path segment TPS is optimized such that the smoothness of the transition path segment TPS is maximized.

[0123] d. Combine milling path segments with transition path segments

[0124] refer to Figure 3 Method 1000 includes step 1020 of generating a subvolume milling path MPSV by combining one or more milling path segments MPS and one or more transition path segments TPS. For example, refer to Figure 13 The first milling path segment MPS1 and the second milling path segment MPS2, along with the first transition path segment TPS1 and the second transition path segment TPS2, are combined to form the sub-volume milling path MPSV. As another example, refer to... Figure 17 The first milling path segment MPSV1 includes the first milling path segment MPS1, the second milling path segment MPSV2 includes the second milling path segment MPS2 and the first transition path segment TPS1, the third milling path segment MPSV3 includes the third milling path segment MPS3 and the second transition path segment TPS2, and the fourth milling path segment MPSV4 includes the fourth milling path segment MPS4 and the third transition path segment TPS3.

[0125] As previously described, method 1000 generates a milling path MP for cutting the cut volume RV by generating a sub-volume milling path MPSV for cutting each cut sub-volume RSV. For example, refer to Figure 17 The milling path MP includes a first sub-volume milling path MPSV1 for cutting the first cut sub-volume RSV1, a second sub-volume milling path MPSV2 for cutting the second cut sub-volume RSV2, a third sub-volume milling path MPSV3 for cutting the third cut sub-volume RSV3, and a fourth sub-volume milling path MPSV4 for cutting the fourth cut sub-volume RSV4.

[0126] In some instances, method 1000 may include the step of generating a connecting transition path segment (TPSC) for connecting sub-volume milling paths (MPSVs). One or more connecting transition path segments (TPSCs) allow the end effector 20 to move from a sub-volume milling path (MPSV) of a first section S to a sub-volume milling path (MPSV) of an adjacent second section S. For example, refer to... Figure 17 The first connecting transition path segment TPSC1 connects the first milling path segment MPS1 of the first sub-volume milling path MPSV1 to the second milling path segment MPS2 of the second sub-volume milling path MPSV2; the second connecting transition path segment TPSC2 connects the second milling path segment MPS2 of the second sub-volume milling path MPSV2 to the third milling path segment MPS3 of the third sub-volume milling path MPSV3; and the third connecting transition path segment TPSC3 connects the third milling path segment MPS3 of the third sub-volume milling path MPSV3 to the fourth milling path segment MPS4 of the third sub-volume milling path MPSV4. Although Figure 17 The connecting transition path segment TPSC is generated between milling path segments MPS, but in other instances, the connecting transition path segment TPSC can be generated between transition path segments TPS, or between a transition path segment TPS and a milling path segment MPS.

[0127] The connecting transition path segment TPSC extends along the boundary 76 of the protected volume between adjacent sections S. For example... Figure 17 As shown, the first connecting transition segment TPSC1 extends along boundary 76 between the first sub-volume milling path MPSV1 and the second sub-volume milling path MPSV2, the second connecting transition segment TPSC2 extends along boundary 76 between the second sub-volume milling path MPSV2 and the third sub-volume milling path MPSV3, and the third connecting transition segment TPSC3 extends along boundary 76 between the third sub-volume milling path MPSV3 and the fourth sub-volume milling path MPSV4.

[0128] In some instances, connecting transition path segments (TPSC) can be combined to form a spiral. For example, see reference... Figure 18A and Figure 18B The connecting transition path segment TPSC connects the sub-volume milling paths MPSV of the milling path MP, extends along boundary 76, and combines to form a spiral between the sub-volume milling paths MPSV. The spiral shape of the connecting transition path segment TPSC can be useful in instances where the connecting transition path segment TPSC connects sub-volume milling paths MPSV that do not include a transition path segment TPS. In such instances, the cut sub-volume RSV to be removed by the sub-volume milling path MPSV may not be interrupted by gaps. By forming a spiral shape, the connecting transition path segment TPSC optimizes the path of the end effector 20 as it travels from one sub-volume milling path MPSV to another, and facilitates complete removal of the cut sub-volume RSV. For example, the spiral shape allows the end effector 20 to travel a shorter distance when moving from one sub-volume milling path MPSV to another. As such, the spiral shape allows the end effector 20 to remove the cut volume RV in less time. Furthermore, the spiral shape reduces the number of sharp turns that the end effector 20 makes when traveling from one sub-volume milling path (MPSV) to another. Since sharp turns can leave marks on the bone, the spiral shape allows the end effector 20 to smoothly remove the cut volume (SV).

[0129] While this document describes the connecting transition path segments TPSC as a combination to form a spiral, in other instances, the connecting transition path segments TPSC can form any other suitable shape. For example, the connecting transition path segments TPSC can form any other shape suitable for optimizing the path of the end effector 20 and facilitating the complete removal of the cut volume RV.

[0130] Although specific features of various embodiments of this disclosure may be shown in some of the accompanying drawings and not in others, this is merely for convenience. Any feature of the drawings or other embodiments may be referenced and / or claimed in combination with any feature of any other drawing or embodiment, based on the principles of this disclosure.

[0131] This written description uses examples to illustrate embodiments of this disclosure and also enables those skilled in the art to practice the embodiments, including making and using any device or system and performing any combined methods. The patentable scope of this disclosure is defined by the claims and may include other examples that would occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are subtly different from the literal language of the claims.

Claims

1. A computer-implemented method for generating milling paths for a tool for a surgical system, the milling paths being designed to enable the tool to remove material from bone defining a socket for a joint, the computer-implemented method comprising: Obtain a model of the bone including the socket; The allowable volume intersects with the model of the socket to define the resection volume intended to be removed from the bone; Generate multiple cross sections; For at least one cross section: A sub-volume corresponding to the cross-section that identifies the cut-off volume; Generate one or more milling path segments designed to enable the tool to remove the sub-volume of the cut-off volume; For each sub-volume of the cut-off volume, an area to be avoided by the tool is identified; Generate one or more transition path segments designed to avoid the region; as well as The milling path is generated by combining the one or more milling path segments and the one or more transition path segments.

2. The computer-implemented method as described in claim 1, further comprising: A safeguard volume is generated within the allowable volume, wherein the safeguard volume defines a boundary with respect to the tool, wherein the allowable volume defines a boundary with respect to the tool, wherein the boundary of the safeguard volume is spaced apart from the boundary of the allowable volume, and wherein one or more transition path segments are defined by the geometry of the safeguard volume.

3. The computer-implemented method as described in any of the preceding claims, further comprising: The sub-volume that identifies the excised volume is defined by a gap interrupting the absence of the excised volume, wherein the area to be avoided by the tool includes the gap.

4. The computer-implemented method as described in claim 3, further comprising: Determine whether the size of the gap is greater than a threshold, and generate the one or more transition path segments in response to determining that the size of the gap is greater than the threshold.

5. The computer-implemented method as described in claim 2, further comprising: An inner allowable volume is generated within the allowable volume, the inner allowable volume defining a boundary for the tool, wherein the boundary of the inner allowable volume is spaced apart from the boundary of the allowable volume, and wherein the safeguard volume is defined within the inner allowable volume, and the boundary of the safeguard volume is spaced apart from the inner allowable volume.

6. The computer-implemented method of claim 5, wherein the tool comprises a spherical cutting drill having a drill radius, and wherein the boundary of the internal allowable volume is spaced apart from the boundary of the allowable volume by the drill radius.

7. The computer-implemented method of any one of claims 5 and 6, wherein the permitted volume extends along the axis.

8. The computer-implemented method of claim 7, wherein the allowable volume, the internal allowable volume, and the safeguard volume are coaxial around the axis.

9. The computer-implemented method of claim 7, wherein the allowable volume, the internal allowable volume, and the safeguard volume are each rotationally symmetric.

10. The computer-implemented method of claim 7, wherein the cross section is further defined as a sector extending radially from the axis toward the boundary of the permissible volume.

11. The computer-implemented method of claim 10, wherein the sector is defined as a boundary perpendicular to the allowable volume.

12. The computer-implemented method of any one of claims 10 and 11, wherein the sector is further defined as a first sector, wherein the section adjacent to the cross section is further defined as a second sector, and wherein the sub-volume corresponding to the first sector that identifies the cut volume includes the sub-volume located between the first sector and the second sector that identifies the cut volume.

13. The computer-implemented method of any one of claims 5 to 12, wherein the one or more milling path segments are generated based on the intersection of the internal allowable volume and the cross section.

14. The computer-implemented method of any one of claims 5 to 13, wherein generating the one or more transition path segments comprises generating one or more transition path segments for connecting the one or more milling path segments of the at least one cross section, and wherein the one or more transition path segments extend along the cross section between the one or more milling path segments and the boundary of the safeguard volume.

15. The computer-implemented method as described in claim 2, comprising: A connecting transition path segment is generated to connect the milling path segment of the first cross section and the milling path segment of the adjacent second cross section, wherein the connecting transition path segment extends along the boundary of the protected volume between the first cross section and the adjacent second cross section.

16. The computer-implemented method of claim 15, wherein the plurality of connecting transition path segments form a spiral extending along the boundary of the protected volume.

17. The computer-implemented method as described in any of the preceding claims, wherein the geometry of the permissible volume is based on the geometry of the implant to be inserted into the socket.

18. The computer-implemented method of any one of claims 7 to 17, wherein the permissible volume includes a cylindrical portion, the cylindrical portion including a first end and a second end along the axis, the first end and the second end defining the height of the cylindrical portion.

19. The computer-implemented method of claim 18, wherein the permissible volume includes a spherical cap portion having a center located on the axis, and wherein the spherical cap portion is integrated with the cylindrical portion and extends from the second end of the cylindrical portion.

20. The computer-implemented method as described in any of the preceding claims, wherein the skeleton is the pelvis or scapula.

21. A non-transitory computer-readable medium comprising instructions executable by one or more processors, wherein the instructions implement a software program for generating milling paths for a tool for a surgical system, the milling paths being designed to enable the tool to remove material from bone defining a socket for a joint, the software program being configured to: Obtain a model of the bone including the socket; The allowable volume intersects with the model of the socket to define the resection volume intended to be removed from the bone; Generate multiple cross sections; For at least one cross section: A sub-volume corresponding to the cross-section that identifies the cut-off volume; Generate one or more milling path segments designed to enable the tool to remove the sub-volume of the cut-off volume; For each sub-volume of the cut-off volume, an area to be avoided by the tool is identified; Generate one or more transition path segments designed to avoid the region; as well as The milling path is generated by combining the one or more milling path segments and the one or more transition path segments.

22. A surgical system comprising: A manipulator, comprising a robotic arm formed by multiple links and joints and supporting a tool; A control system configured to generate a milling path designed to enable the tool to remove material from bone defining a socket for a joint, wherein, in order to generate the milling path, the control system is configured to: Obtain a model of the bone including the socket; The allowable volume intersects with the model of the socket to define the resection volume intended to be removed from the bone; Generate multiple cross sections; and For at least one cross section: A sub-volume corresponding to the cross-section that identifies the cut-off volume; Generate one or more milling path segments designed to enable the tool to remove the sub-volume of the cut-off volume; For the sub-volume of the said excised volume, the area to be avoided by the tool is identified; and Generate one or more transition path segments designed to avoid the region; and The milling path is generated by combining the one or more milling path segments and the one or more transition path segments; The control system is configured to control the manipulator to move the tool along the generated milling path.

23. A computer-implemented method for generating milling paths for a tool for a surgical system, the milling paths being designed to enable the tool to remove material from bone defining a socket for a joint, the computer-implemented method comprising: Obtain a model of the bone including the socket; The allowable volume intersects the model of the socket to define a resection volume intended to be removed from the bone, wherein the allowable volume defines a boundary with respect to the tool; as well as A first cross section and a second cross section are generated, wherein the first cross section is adjacent to the second cross section; The distance between the first cross section and the second cross section is based on the residual height.

24. A computer-implemented method for generating milling paths for a tool for a surgical system, the milling paths being designed to enable the tool to remove material from bone defining a socket for a joint, the computer-implemented method comprising: Obtain a model of the bone including the socket; The allowable volume intersects the model of the socket to define a resection volume intended to be removed from the bone, wherein the allowable volume defines a boundary with respect to the tool; A protective volume is defined within the allowable volume, wherein the protective volume defines a boundary for the tool, and wherein a distance is defined between the boundary of the protective volume and the boundary of the allowable volume; Generate multiple cross sections; For the plurality of cross sections, sub-volumes of the cut-off volume are identified and milling paths are generated, the milling paths being designed to enable the tool to remove the sub-volumes of the cut-off volume; as well as Generate multiple transition path segments for connecting milling paths between adjacent sections, wherein the multiple transition path segments extend along the boundary of the protected volume between adjacent sections and form a spiral.

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