Design assistance system, design assistance method, and design assistance program

Abstract

This design assistance device receives input of first information pertaining to a first shape of a portion of a body, selects, from a first candidate group including a plurality of items of second information pertaining to a second shape of an implant, the plurality of items of second information that satisfy a first condition in relation to the first information as a second candidate group, and selects, from at least a portion of the items of second information included in the second candidate group, the items of second information that satisfy a second condition different from the first condition as a third candidate group.

Description

Design support system, method and program

[0001] The present invention relates to a design support system, a design support method, and a design support program for supporting the design of an implant.

[0002] When a part of the body is injured or deformed, an implant for that part may be used. Since the shape and size of the part usually vary from person to person, the implant must be designed to suit the individual who will use it. For example, Patent Document 1 discloses a computer-implemented method for designing a patient-specific orthopedic implant.

[0003] Special Publication No. 2022-509995

[0004] A design support system, a design support method, and a design support program according to one aspect of the present disclosure accept input of first information regarding a first shape of a body part, select a plurality of pieces of second information regarding a second shape of an implant from a first candidate group including a plurality of pieces of second information as a second candidate group, the plurality of pieces of second information satisfying a first condition in relation to the first information, and select a third candidate group from at least some of the second information included in the second candidate group, the plurality of pieces of second information satisfying a second condition different from the first condition.

[0005] These and other objects, features and advantages of the present invention will become apparent from the following detailed description and accompanying drawings.

[0006] 1 is a block diagram illustrating a configuration of a design support system according to an embodiment; FIG. 2 is a diagram illustrating, by way of example, parameters related to a shape; FIG. 3 is a diagram illustrating, by way of example, an increase or decrease in the number of points in a first region and point cloud data; FIG. 4 is a diagram illustrating, by way of example, output of a selection result; FIG. 5 is a flowchart illustrating an operation of a design support device according to an embodiment; FIG. 6 is a diagram illustrating, by way of example, grouping of a plurality of pieces of second information belonging to a first candidate group; FIG. 7 is a diagram illustrating generation of an inverted shape; FIG. 8 is a diagram illustrating generation of a deformed shape; FIG. 9 is a diagram illustrating generation of a cartilage-added shape to which cartilage has been added; FIG. 10 is a diagram illustrating generation of an enlarged or reduced shape to which a shape has been enlarged or reduced; FIG. 11 is a diagram illustrating replacement of a radius of curvature; FIG. 12 is a diagram illustrating generation of new parameters; FIG. 13 is a diagram illustrating conversion to distance; FIG. 14 is a diagram illustrating optimization of a second shape; and FIG. 15 is a diagram illustrating display of a difference amount, by way of example.

[0007] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. In addition, components with the same reference numerals in each drawing indicate the same components, and their description will be omitted as appropriate. In this specification, when referring to a general term, a reference numeral without a subscript is used, and when referring to an individual component, a reference numeral with a subscript is used.

[0008] In recent years, there has been a demand for an implant design support system, an implant design support method, and an implant design support program that can efficiently select useful implants. Accordingly, a design support system according to an embodiment is a system for supporting implant design, and includes an input unit, a first selection processing unit, and a second selection processing unit. The input unit accepts input of first information relating to a first shape of a body part. The first selection processing unit selects, from a first candidate group including a plurality of pieces of second information relating to a second shape of the implant, a plurality of pieces of second information that satisfy a first condition in relation to the first shape as a second candidate group. The second selection processing unit selects, from at least some of the second information included in the second candidate group, the second information that satisfies a second condition different from the first shape as a third candidate group, and further associates order information relating to the order in the second condition with the second information.

[0009] Such a design support system, as well as a design support method and a design support program implemented therein, will be described in more detail below. The design support system may be configured by interconnecting an input / output terminal device that inputs and outputs data, one or more arithmetic processing devices (e.g., a server device) that executes various arithmetic processing, and one or more database devices that store (manage) various data. Alternatively, at least some of the input / output terminal device, one or more arithmetic processing devices, and one or more database devices may be integrated and interconnected to communicate with the remaining devices. Here, the design support system will be described using an example of a design support device that is fully integrated. The implant design support program may be recorded on a non-transitory recording medium, or may be downloaded via a network, for example.

[0010] FIG. 1 is a block diagram showing the configuration of a design support system (a design support device as an example) in an embodiment. FIG. 2 is a diagram for explaining, as an example, parameters related to a shape. FIGS. 2A to 2D show parameters of first to fourth aspects. FIG. 3 is a diagram for explaining, as an example, an increase or decrease in the number of points in a first region and point cloud data. FIG. 4 is a diagram for explaining, as an example, output of a selection result.

[0011] A design support system (design support device as an example) 1000 in an embodiment includes, for example, a control processing unit 1, an input unit 2, an output unit 3, an interface unit (IF unit) 4, and a memory unit 5, as shown in FIG. 1 .

[0012] The input unit 2 is connected to the control processing unit 1, and is a device for inputting various data necessary for operating the design support device 1000, such as various commands such as a command to start implant design support, first information on the shape of a body part (first shape), the name of the implant, and the area (first area) to be set for the implant, into the design support device 1000. The input unit 2 may have, for example, a keyboard, a mouse, and a plurality of input switches to which predetermined functions are assigned.

[0013] The implant is a medical device or component implanted in the body of an animal (including a human), such as an implant for a bone, joint, cartilage, muscle, or tooth root. The implant may be, for example, an implant for a skull, tooth root, auditory ossicles, spine, sternum, ribs, clavicle, humerus, radius, ulna, carpal bones, metacarpal bones, phalanges, hip bones, femur, patella, tibia, fibula, tarsal bones, metatarsal bones, phalanges, temporomandibular joints, hip joints, knee joints, or talus. The implant may be, for example, a pair of implants for a portion of an animal's body, one for each side. When the pair of left and right parts of an animal's body are bones, the implant may be, for example, an implant for a part of the skull (parietal bone, temporal bone, nasal bone, lacrimal bone, maxilla, and cheekbone), a tooth root, an ossicle, a rib, a clavicle, a humerus, a radius, an ulna, a carpal bone, a metacarpal bone, a phalange, an ilium, a femur, a patella, a tibia, a fibula, a tarsal bone, a metatarsal bone, a phalange, a temporomandibular joint, a hip joint, a knee joint, or a talus.

[0014] The body part may be at least a part of a bone, cartilage, muscle, or artificial tooth root of an animal (including a human). Furthermore, the body part may be, for example, either one of the pair of left and right parts. When the body part is a bone, the first region may be either one of the pair of left and right bones.

[0015] The output unit 3 is connected to the control processing unit 1 and is a device that outputs commands, data, processing results, etc. input from the input unit 2 in accordance with the control of the control processing unit 1, and is, for example, a display device such as a CRT display (cathode ray tube display), LCD (liquid crystal display), or organic photoluminescence display, or a printing device such as a printer.

[0016] The input unit 2 and the output unit 3 may be configured as a touch panel. In this case, the input unit 2 is a position input device, such as a resistive or capacitive type, that detects an operation position and inputs the position, and the output unit 3 is a display device. In this touch panel, a position input device is provided on the display surface of the display device, and one or more input content candidates that can be input are displayed on the display device. When a user touches a display position that displays the input content they want to input, the position is detected by the position input device, and the display content displayed at the detected position is input to the design support device 1000 as the user's operation input content. Such a touch panel makes it easy for the user to intuitively understand input operations, thereby providing a design support device 1000 that is easy for the user to use.

[0017] The IF unit 4 is connected to the control processing unit 1 and is a circuit that inputs and outputs data to and from, for example, an external device under the control of the control processing unit 1, such as an interface circuit for RS-232C, which is a serial communication method, an interface circuit using the Bluetooth (registered trademark) standard, or an interface circuit using the USB (Universal Serial Bus) standard. The IF unit 4 may also be a communication interface circuit that transmits and receives communication signals to and from an external device, such as a data communication card or a communication interface circuit conforming to the IEEE 802.11 standard.

[0018] The storage unit 5 is connected to the control processing unit 1 and is a circuit that stores various predetermined programs and various predetermined data under the control of the control processing unit 1.

[0019] The various predetermined programs include, for example, a control processing program, and the control processing program includes, for example, a control program, a first selection processing program, a second selection processing program, and a data number increasing / decreasing program. The control program is a program that controls each of the units 2 to 5 of the design support device 1000 according to the function of each unit. The first selection processing program is a program that selects, from a first candidate group including a plurality of pieces of second information regarding the shape of the implant (second shape), a plurality of pieces of second information that satisfy a first condition in relation to the first information as a second candidate group. The second selection processing program is a program that selects, from the second candidate group, a piece of second information that satisfies a second condition different from the first condition as a third candidate group. The data number increasing / decreasing program is a program that executes at least one of a thinning process and an interpolation process.

[0020] The various predetermined data include, for example, the first information received by the input unit 2, the second information of the first candidate group, the name of the implant, the first area set for the implant, various processing results during processing, and the final processing result, which are necessary for executing each of these programs.

[0021] The storage unit 5 includes, for example, a ROM (Read Only Memory), which is a nonvolatile storage element, or an EEPROM (Electrically Erasable Programmable Read Only Memory), which is a rewritable nonvolatile storage element. The storage unit 5 also includes a RAM (Random Access Memory), which serves as a working memory for the control processing unit 1 and stores data generated during execution of the predetermined program. The storage unit 5 may also include a hard disk drive (HDD), a solid state drive (SSD), or the like, which have a relatively large storage capacity.

[0022] The memory unit 5 functionally includes a first memory unit 51, a second memory unit 52, and a third memory unit 53. The first memory unit 51 stores the first candidate group. The second memory unit 52 stores the second candidate group. The third memory unit 53 stores the third candidate group. Here, the first candidate group may have multiple pieces of second information (second shape information, second shape data) as elements. The second candidate group may have multiple pieces of second information (first selection information) as elements. The third candidate group may have one or multiple pieces of second information (second selection information) as elements. In other words, the first candidate group may include multiple pieces of second information, the second candidate group may include multiple pieces of second information, and the third candidate group may include one or multiple pieces of second information.

[0023] The first shape and the second shape may each be represented by solid data, or may each be represented by point cloud data (three-dimensional coordinate values) that represents the surface shape (outer contour shape). In this embodiment, a case will be described in which the first shape and the second shape are represented by point cloud data, but this is not limiting.

[0024] In generating the point cloud data of the first shape (first point cloud data), for example, solid data of the body portion is generated based on image data of the body portion using a known method, and the first point cloud data is generated based on the generated solid data using a known method. Here, the image data may be three-dimensional image data, such as a CT image (computed tomography image), an MRI image (magnetic resonance imaging image), or an echo image. The point cloud data of the second shape (second point cloud data) may be, for example, second point cloud data of an implant previously designed using CAD or the like, or second point cloud data generated similarly to the first point cloud data of the first shape based on image data of a specific part for which an implant is to be designed. The point cloud data of the second shape (second point cloud data) may be, for example, data generated by the scaled shape generation unit 18 and the parameter generation unit 19 described below.

[0025] The first candidate group may be input to the design support device 1000 from the input unit 2 and stored in the first storage unit 51. Alternatively, the first candidate group may be stored (recorded) on a storage medium such as a USB memory or an SD card (registered trademark) or a recording medium such as a CD-R (Compact Disc Recordable) or a DVD-R (Digital Versatile Disc Recordable), input to the design support device 1000 via the IF unit 4, and stored in the first storage unit 51. Alternatively, the first candidate group may be downloaded to the design support device 1000 via the IF unit 4 from, for example, a management server that manages them, and stored in the first storage unit 51.

[0026] The control processing unit 1 is a circuit that controls each of the units 2 to 5 of the design support device 1000 according to the function of each unit, and selects the second candidate group and the third candidate group. The control processing unit 1 is configured to include, for example, a CPU (Central Processing Unit) and its peripheral circuits. When the control processing program is executed, the control processing unit 1 is functionally configured to include a control unit 11, a first selection processing unit 12, a second selection processing unit 13, and a data number increase / decrease unit 14.

[0027] The control unit 11 controls each of the units 2 to 5 of the design support device 1000 in accordance with the function of each unit, and is in charge of overall control of the design support device 1000 .

[0028] The first selection processing unit 12 selects, from a first candidate group including a plurality of pieces of second information regarding the second shape of the implant, a plurality of pieces of second information that satisfy a predetermined first condition in relation to the first information as the second candidate group. That is, from the plurality of pieces of second information belonging to the first candidate group, a plurality of pieces of second information that satisfy the first condition are selected as first selected information, and the first selected information is set as an element of the second candidate group. For example, for each second shape represented by each piece of second information belonging to the first candidate group, the first selection processing unit 12 may compare the second shape with the first shape in terms of the first condition to determine whether the second shape satisfies the first condition, and if the second shape satisfies the first condition, select the second shape as an element of the second candidate group. The first condition may be, for example, a selection condition related to a shape feature (first feature), and the first condition may be a condition for determining the similarity between the first shape and the second shape.

[0029] More specifically, for example, the first condition is that the volume difference between the first shape and the second shape of the second information, which is an element of the first candidate group, is equal to or less than a predetermined threshold (first threshold). In this case, if the volume difference is equal to or less than the first threshold, the first selection processing unit 12 determines that the second shape satisfies the first condition and is similar, and selects the second information of the determined second shape as an element of the second candidate group. The first threshold is set in advance as appropriate from, for example, multiple samples. As a result, from the first number of second information items belonging to the first candidate group, a second number of second information items are selected as first selected information items and are set as elements of the second candidate group in terms of the first condition. Here, the second number may be the same as the first number ((second number) = (first number)) or may be less than the first number ((second number) < (first number)). This allows the similarity of the second shape to the first shape to be determined based on the volume difference.

[0030] Alternatively, for example, the first condition may be that the dimensional product obtained by multiplying the vertical difference, horizontal difference, and height difference between the first shape and a second shape that is an element of the first candidate group is equal to or less than a predetermined threshold (second threshold). In this case, if the dimensional product is equal to or less than the second threshold, the first selection processing unit 12 determines that the second shape satisfies the first condition and is similar, and selects the second information of the determined second shape as an element of the second candidate group. For example, an XYZ Cartesian coordinate system is established for each of the first shape and the multiple second shapes represented by the multiple second information belonging to the first candidate group, and the vertical length (length), horizontal length (width), and height length (height) are defined for each of the mutually orthogonal vertical, horizontal, and height directions, and the vertical difference, horizontal difference, and height difference are calculated to determine the dimensional product. In other words, three linearly independent directions are established, and the differences in each of these three directions are calculated as the vertical difference, horizontal difference, and height difference, to determine the dimensional product. The second threshold is set in advance, for example, appropriately from a plurality of samples. As a result, from the first number of second information items belonging to the first candidate group, a second number of second information items are selected as first selected information items and set as elements of the second candidate group in terms of the first condition. Here, the second number may be the same as the first number ((second number) = (first number)), or may be less than the first number ((second number) < (first number)). This allows for determining whether the second shape is similar to the first shape based on the product of dimensions.

[0031] The second selection processing unit 13 selects, from at least some of the second information included in the second candidate group, the second information that satisfies a second condition different from the first condition as a third candidate group. In other words, from at least some of the second information belonging to the second candidate group, multiple pieces of second information are selected as second selected information from the perspective of the second condition, and are set as elements of the third candidate group. Note that the third candidate group may be selected directly from the second candidate group, or may be selected indirectly from the second candidate group by another process intervening between the second candidate group and the third candidate group. The second condition is, for example, a selection condition regarding a shape feature (second feature) different from the first feature of the shape in the first condition. For example, the second condition is that the shape difference (first shape difference) between the first shape and the second shape is within a predetermined number (third number) in ascending order. In this case, the second selection processing unit 13 selects a third number of second shapes from the plurality of second shapes represented by each of the first selection information pieces, the third number of second shapes having a small shape difference from the first shape, and sets the third number of second information pieces representing the selected third number of second shapes as elements of a third candidate group. When selecting the third number of second shapes, the second selection processing unit 13, for example, calculates the shape difference between each of the plurality of second shapes represented by each of the plurality of first selection information pieces that are elements of the second candidate group, arranges (sorts) the plurality of second shapes in order of the shape difference, and selects the third number of second shapes in order of smallest shape difference. As a result, the second information pieces are selected in order of their shape difference from the first shape, relatively smaller than the second information pieces (first selection information) of the second candidate group that were not selected as the second information pieces (second selection information) belonging to the third candidate group. The third number is appropriately set in advance to a number equal to or smaller than the second number ((third number)≦(second number)). The third number is a shape that is referred to by a user (designer) when designing an implant for the first bone of the subject, and therefore may be set to a small number, such as 3 or 5. This allows a second shape that is less different in shape from the first shape to be selected, and allows an implant that is more useful for designing an implant for the first bone to be selected.

[0032] The second selection processing unit 13 further associates order information regarding the order under the second condition with the second information during the selection. The order under the second condition is, for example, the order of the magnitude of the shape difference. This allows the second shapes represented by the second selection information of the third candidate group to be output to the output unit 3 in the order based on the order information. This allows the user to select the reference implant taking the order into consideration.

[0033] The shape difference may take any one of the following first to fifth modes.

[0034] For example, the second selection processing unit 13 determines a plurality of corresponding points between the first shape and the second shape, and determines the root mean square error (RMSE) of the distance (Euclidean distance) between the determined corresponding points as the shape difference (shape difference of the first aspect). Alternatively, for example, the second selection processing unit 13 may determine the MSE (Mean Squared Error) of the distance (Euclidean distance) between the corresponding points as the shape difference, or, for example, the coefficient of determination R ２ may be calculated as the shape difference. In the search for the corresponding points, for example, the first shape and the second shape are aligned using a known ICP (Iterative Closet Point) algorithm, and for each point in the first point cloud data of the first shape, a point (nearest point) having the shortest Euclidean distance to the point in the second point cloud data of the second shape is searched for as the corresponding point. The ICP algorithm is roughly a method for calculating a rotation matrix and a translation matrix that can best superimpose two shapes.

[0035] Alternatively, for example, the second selection processing unit 13 determines the shape difference as the difference between the value of one shape-related parameter in the second shape and the value of the parameter in the first shape (second-type shape difference). The parameter is appropriately set in advance. This allows the shape difference to be determined from the perspective of the parameter. For example, if the parameter is horizontal, the shape difference can be determined from the perspective of horizontal length.

[0036] Alternatively, for example, the second selection processing unit 13 calculates the difference between each value of a plurality of shape-related parameters in the second shape and each value of the plurality of parameters in the first shape, and calculates the shape difference as a linear sum or a weighted linear sum of the differences (a shape difference of a third aspect). The plurality of parameters are appropriately set in advance. When multiple parameters are set in this manner, each of the multiple parameters may be a parameter whose value changes independently of changes in the values ​​of other parameters. By setting multiple independent parameters, the shape characteristics of each of the multiple second shapes can be appropriately represented by the value of each parameter. In the case of a weighted linear sum, the shape difference can be calculated by emphasizing a parameter that is emphasized.

[0037] The plurality of parameters are, for example, as shown in Fig. 2A, in first to third directions that are orthogonal to each other, a width that is the length of the bone in the first direction, a length that is the length of the bone in the second direction, and a height that is the length of the bone in the third direction (parameters of the first aspect). Figs. 2A to 2D schematically illustrate one of a pair of taluses, left and right, as an example of the bone.

[0038] The plurality of parameters are, for example, the bone volume and the bone surface area (each parameter of the second aspect) as shown in FIG. 2B.

[0039] The multiple parameters are, for example, as shown in Figure 2C, a normalized talar head radius obtained by normalizing (dividing) the talar head radius by the vertical length, a normalized talar trochlear width obtained by normalizing (dividing) the talar trochlear width by the horizontal length, and a normalized talar trochlear radius obtained by normalizing (dividing) the talar trochlear radius by the height (each parameter of the third aspect).

[0040] The plurality of parameters are, for example, the talotrochlear angle and the talocalcaneal joint angle as shown in FIG. 2D (each parameter of the fourth aspect).

[0041] The plurality of parameters may be, for example, all or some of the parameters of the first to fourth aspects.

[0042] The independence of each parameter can be determined by, for example, the correlation coefficient R (or the coefficient of determination R) between the parameters of the second shapes represented by the second information belonging to the first candidate group. ２ , 0≦R ２ The coefficient of determination R between two parameters is determined based on the following: ２ is equal to or less than a preset threshold (independence determination threshold, for example, 0.7 or 0.6), the two parameters are determined to be independent, and the coefficient of determination R ２ exceeds the independence determination threshold, the two parameters are determined to be not independent, i.e., dependent. More specifically, two parameters are selected from a plurality of parameters, and it is determined whether they are independent or not. This process is repeated until two independent parameters are selected. When two independent parameters are selected, one of the two parameters is selected, and for this selected parameter, an independent parameter is selected from the plurality of parameters excluding this selected parameter. In this way, independent parameters are selected from the plurality of parameters.

[0043] Alternatively, for example, the independence of each parameter is determined by principal component analysis. More specifically, principal component analysis is performed on the plurality of parameters, a predetermined number of principal components are selected from a first principal component, and the independent principal components are set as the independent parameters. For example, when the first bone and the implant are a specific bone, such as a talus, in each parameter of the first aspect, the length is independent, and the width and height are each dependent on the length.

[0044] Each weight for the multiple parameters in the weighted linear sum is set based on the distribution of parameter values. This allows each weight to be set according to the distribution. The wider the distribution, the greater the shape change, and the more characteristic the shape can be determined, and the weight can be increased. For example, each weight is set based on the standard deviation σ of the parameters for the multiple second shapes in the first candidate group. In one example, if the standard deviation of the first parameter is σ1 and the standard deviation of the second parameter independent of the first parameter is σ2, the weight W1 of the first parameter is set to (σ1 / (σ1+σ2))×w, and the weight W2 of the second parameter is set to (σ2 / (σ1+σ2))×w. Alternatively, for example, if the standard deviation of a first parameter is σ1 and the standard deviation of a second parameter independent of the first parameter is σ2, and if WD1 is the distribution range from -σ1 to +σ1 and WD2 is the distribution range from -σ2 to +σ2, then the weight W1 of the first parameter is (WD1 / (WD1+WD2))×w, and the weight W2 of the second parameter is (WD2 / (WD1+WD2))×w. In this case, σ1 and σ2 may be 1σ (=1×σ), 2σ (=2×σ), or the like. Alternatively, for example, the weights are set based on the coefficient of variation CV of the parameters for the plurality of second shapes in the first candidate group. In one example, when the coefficient of variation of a first parameter is CV1 and the coefficient of variation of a second parameter independent of the first parameter is CV2, the weight W1 of the first parameter is set to (CV1 / (CV1+CV2))×w, and the weight W2 of the second parameter is set to (CV2 / (CV1+CV2))×w, where w is a value appropriately set in advance. Alternatively, for example, the weights are set based on the standard deviations and coefficients of variation of the parameters for a plurality of second shapes in the first candidate group. In one example, the weight W1 of the first parameter is set to (σ1 / (σ1+σ2))×(CV1 / (CV1+CV2))×w, and the weight W2 of the second parameter is set to (σ2 / (σ1+σ2))×(CV1 / (CV1+CV2))×w.

[0045] Alternatively, for example, the second selection processing unit 13 determines a plurality of corresponding points between the first shape and the second shape, determines the root mean square error of the distance between the determined corresponding points, determines the difference between the value of one shape-related parameter in the second shape and the value of the parameter in the first shape, and determines the shape difference as the linear sum or weighted linear sum of the determined root mean square error and the determined difference (shape difference of the fourth aspect).

[0046] Alternatively, for example, the second selection processing unit 13 determines a plurality of corresponding points between the first shape and the second shape, determines the root mean square error of the distance between the determined corresponding points, determines the differences between each value of a plurality of shape-related parameters in the second shape and each value of the plurality of parameters in the first shape, and determines the shape difference as a linear sum or a weighted linear sum of the determined root mean square error and each determined difference (shape difference of the fifth aspect).

[0047] The data number adjusting section 14 performs at least one of a thinning process and an interpolation process.

[0048] The thinning process may be a process of generating second point cloud data of second information of a new second candidate group by thinning out second point cloud data within a predetermined first region in the second shape. The thinning process may be a process of generating first point cloud data of new first information by thinning out first point cloud data within a second region in the first shape corresponding to the first region. The thinning process for the second shape may be performed on multiple pieces of second information belonging to the first candidate group, or may be performed on each of multiple pieces of second information (first selected information) belonging to the second candidate group. When performing the thinning process on multiple pieces of second information belonging to the first candidate group, the multiple pieces of second information after the thinning process may be stored in advance in the first storage unit 51 as a first candidate group, or the thinning process may be performed each time the first selection process is performed. When performing the thinning process on the second shape on the first candidate group, the thinning process on the first shape may be performed before the first selection process. When the thinning process for the second shape is performed on the second candidate group, the thinning process for the first shape may be performed after the first selection process and before the second selection process. In the following, a case where the thinning process for the second shape is performed on the second candidate group will be described, but this is not limiting.

[0049] For example, as shown in FIG. 3 , a first selected shape GE1 is displayed on the output unit 3, and two points PT1 and PT2 are input and specified via the input unit 2. A rectangular shape having a diagonal line with the specified two points PT1 and PT2 as its two end points is defined as a first region AR1. Next, points are sampled at a predetermined point interval from the point cloud data within the first region AR1 of the second shape GE1 represented by the first selection information, and these points are used as point cloud data for the second information of a new second candidate group. Then, points are sampled at the same point interval from the point cloud data within the second region of the first shape, and these points are used as point cloud data for a new first shape. For example, points are sampled every two or three points. The first region may be a predetermined region.

[0050] The interpolation process generates second point cloud data of second information of a new second candidate group and first point cloud data of new first information by interpolating second point cloud data within a predetermined third region in the second shape and first point cloud data within a second region corresponding to the third region in the first shape. The interpolation process for the second shape may be performed for multiple pieces of second information belonging to the first candidate group, or may be performed for each of multiple pieces of second information (first selected information) belonging to the second candidate group. When performing the interpolation process for multiple pieces of second information belonging to the first candidate group, the multiple pieces of second information after the interpolation process may be stored in advance in the first storage unit 51 as a first candidate group, or the interpolation process may be performed each time the first selection process is performed. When the interpolation process for the second shape is performed for the first candidate group, the interpolation process for the first shape may be performed before the first selection process. When the interpolation process for the second shape is performed for the second candidate group, the interpolation process for the first shape may be performed after the first selection process and before the second selection process. In the following, a case where the interpolation process for the second shape is performed on the second candidate group will be described, but this is not limited to this. For example, linear interpolation, spline interpolation, Bezier interpolation, etc. are used for the interpolation. The third region may be a region set in advance. The third region may be a region different from the first region.

[0051] The second selection processing unit 13 then selects the third candidate group using the second point cloud data of the second information of the new second candidate group generated by the data number increasing / decreasing unit 14 and the first point cloud data of the new first information. Therefore, by performing the thinning process, it is possible to designate an area that is not important in implant design as the first area, thereby reducing the selection process of the second selection processing unit 13. On the other hand, by performing the interpolation process, it is possible to designate an area that is important in implant design as the fourth area, thereby enabling the second selection processing unit 13 to more appropriately select the second information (second selection information), which is an element of the third candidate group.

[0052] Then, the control unit 11 outputs the third number of second shapes (implants) represented by the third number of second selection information selected by the second selection processing unit 13 to the output unit 3. For example, the control unit 11 causes the output unit 3 to output the third number of second shapes (implants) so that they are arranged in order of increasing shape difference from the first shape. For example, when the third number is four, as shown in Fig. 4 , the four shapes of implant model 1 to implant model 4 are arranged in order of decreasing shape difference from the top left to the bottom right of the page and output to the output unit 3.

[0053] The control processing unit 1, input unit 2, output unit 3, IF unit 4 and storage unit 5 can be configured by, for example, a desktop or notebook computer.

[0054] Next, the operation of this embodiment will be described with reference to a flowchart shown in FIG.

[0055] When the design support device 1000 having such a configuration is powered on, it initializes the necessary units and starts its operation. The control processing unit 1 executes a control processing program to functionally configure a control unit 11, a first selection processing unit 12, a second selection processing unit 13, and a data number increase / decrease unit 14. When the design support device 1000 starts its operation, it displays a predetermined home screen including a predetermined menu bar on the output unit 3. The menu bar includes a "Start Support" button for instructing the start of design support.

[0056] When the input operation of the "Start Support" button by the user (operator) is accepted via the input unit 2, the design support device 1000 accepts input of first information regarding a first shape of a first bone of the subject via the control unit 11 of the control processing unit 1 (S1). Here, as an example, the description will be given assuming that the body part is the first bone of the subject, but this is not limited thereto. The output unit 3 displays an input screen displaying a message prompting the user to input the first information, and the user inputs the first information, for example, information (affected bone information) representing the shape of an affected bone (an example of the first bone) of a patient (an example of the subject) for whom an implant is desired to be designed, into the input unit 2. It is assumed that a first memory unit 51 of the memory unit 5 stores a plurality of second information items belonging to a first candidate group.

[0057] Next, the design support device 1000 selects, from the first candidate group stored in the first memory unit 51, a plurality of second information items that satisfy the first condition as a second candidate group using the first selection processing unit 12 of the control processing unit 1, and stores the second information (first selection information) of this selected second candidate group in the second memory unit 52 (S2).

[0058] Next, the design support device 1000 determines whether to increase or decrease the number of data points in the point cloud data using the data number increase / decrease unit 14 of the control processing unit 1 (S3). For example, the data number increase / decrease unit 14 displays a data number increase / decrease inquiry screen for inquiring about increasing or decreasing the number of data points on the output unit 3. This data number increase / decrease inquiry screen includes, for example, an inquiry message display area for displaying an inquiry message such as "Do you want to increase or decrease the number of data points?", an area input area for displaying the implant and inputting the first area or the third area AR1 to be set for the implant, an "Increase" button for inputting an instruction to increase the number of data points, a "Decrease" button for inputting an instruction to decrease the number of data points, and a "Do not increase / decrease" button for inputting an instruction not to increase or decrease the number of data points.

[0059] When the user increases the number of data, the user inputs the third area AR1 using the area input area and operates the "Increase" button. In this case, the data number increase / decrease unit 14 determines that the number of data is to be increased or decreased based on the result of the determination, and then executes process S4. In process S4, the data number increase / decrease unit 14 executes the interpolation process, and then executes process S5.

[0060] When the user wishes to reduce the number of data items, the user inputs the first area AR1 using the area input area and presses the "Decrease" button. In this case, the data number adjuster 14 determines that the number of data items has been reduced, and then executes step S4. In step S4, the data number adjuster 14 executes the thinning process, and then executes step S5.

[0061] If the user does not want to increase or decrease the number of data items, the user presses the "No increase or decrease" button. In this case, the data item number increase / decrease unit 14 determines not to increase or decrease the number of data items as a result of the determination, and then executes step S5.

[0062] In this process S5, the design supporting device 1000 causes the second selection processing unit 13 of the control processing unit 1 to select, as a third candidate group, second information that satisfies the second condition from the second candidate group stored in the second storage unit 52, and stores the second information (second selection information) of the selected third candidate group in the third storage unit 53. During this selection, the second selection processing unit 13 associates order information with the second selection information.

[0063] Then, in the design support device 1000, the control unit 11 of the control processing unit 1 outputs to the output unit 3 a display screen (selection result display screen) that displays the third number of second shapes (implants) represented by each of the third number of second selection information selected by the second selection processing unit 13, arranged in order of smallest shape difference (S6), and this process ends. Note that the control unit 11 may output the second selection information to an external device via the IF unit 4 as necessary.

[0064] As described above, the design support device 1000 and the design support method and design support program implemented therein in the embodiment select the second information from the second information belonging to the first candidate group in two stages, under the first and second conditions, respectively, and therefore can efficiently select an implant that can be used as a reference when designing an implant for the first bone.

[0065] In the above-described embodiment, the plurality of pieces of second information belonging to the first candidate group may be divided into a plurality of groups based on the distribution of shape parameters in the second shape, and each group may be stored in the first storage unit 51 in association with a group ID (first modified embodiment). The group ID is an identifier for specifying and identifying the group. This allows for more efficient and appropriate selection of implants that can be used as reference for designing the implant for the first bone.

[0066] 6A and 6B are diagrams illustrating an example of grouping multiple pieces of second information belonging to the first candidate group. Fig. 6A shows a distribution with two peaks, and Fig. 6B shows a distribution with three peaks. The horizontal axes in Fig. 6A and 6B represent the class of the parameter, and the vertical axes represent the frequency (number).

[0067] For example, if the frequency distribution (histogram) of multiple second shapes represented by multiple pieces of second information for a parameter has two peaks PK11 and PK12 as shown in Figure 6A, the multiple pieces of second information are divided by the parameter value PV11 that is intermediate between the two peaks PK11 and PK12, and are divided into second information of a first A group G1A having parameter values ​​within the first A range from 0 to the parameter value PV11, and second information of a first B group G1B that is within the first B range that exceeds the parameter value PV11. Alternatively, for example, if the frequency distribution of a plurality of second shapes represented by each of the plurality of second information for a parameter has three peaks PK21, PK22, and PK23 as shown in Figure 6B, the plurality of second information are divided by a parameter value PV21 that is intermediate between the two peaks PK21 and PK22, and a parameter value PV22 that is intermediate between the two peaks PK22 and PK23, and are divided into second information of a second A group G2A having parameter values ​​within the second A range from 0 to the parameter value PV21, second information of a second B group G2B having parameter values ​​within the second B range from the parameter value PV21 to the parameter value PV22, and second information of a second C group G2C that is within the second C range exceeding the parameter value PV23.

[0068] In such a case, the first selection processing unit 12 first performs a preliminary selection process to select a group to which the first information of the first shape belongs based on the parameter value of the first shape, and then selects first selection information from the second information belonging to the selected group, thereby generating a second group of candidates.

[0069] In the above-described embodiment, the design support device 1000 may also include an inverted shape generator 15 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 1 (second modified embodiment). In this case, the first bone is one of a pair of left and right bones, or one of a pair of left and right taluses. The input unit 2 accepts input of third information regarding a third shape of the other second bone of the pair of left and right bones, or third information regarding the third shape of the other second bone of the pair of left and right taluses. The inverted shape generator 15 then generates, as the first shape to be used in the first selection processing unit 12, a shape obtained by left-right inverting the third shape of the third information accepted by the input unit 2.

[0070] FIG. 7 is a diagram illustrating an example of generating an inverted shape. For example, the menu bar includes an "Invert" button for instructing the generation of an inverted shape. When the user presses the "Invert" button via the input unit 2, the design support device 1000 causes the control unit 11 of the control processing unit 1 to display an input screen displaying a message prompting the user to input the third information. The user then inputs the third information via the input unit 2. When the input of the third information is received, for example, as shown in FIG. 7 , a virtual symmetry plane VS is disposed for the third shape SH11. For each point in the point cloud data of the third shape SH11, a corresponding point PG2 is determined from the virtual symmetry plane VS on the side opposite to the side where the third shape SH11 is disposed, at a distance between the point PG1 and the virtual symmetry plane VS. Each of the corresponding points becomes a point in the point cloud data of a shape SH12 obtained by horizontally inverting the third shape SH11. In addition, the file name of the second shape may be given a symbol representing right (e.g., "R") or left (e.g., "L"), and the inverted shape may be automatically generated by referencing this.

[0071] According to this, if there is no first information representing the first shape but instead there is third information representing the third shape of a second bone paired with the first bone, the first information can be generated from this third information. When the first bone is an affected bone, if the second selection information is selected based on the first shape of the affected bone, there is a risk that the second shape will be selected which has an error compared to the first shape before it became an affected bone. However, by selecting the second selection information based on the first shape generated from the third shape of the healthy bone paired with the affected bone, the error can be reduced, and an implant that can be used as a reference for designing an implant for the first bone can be more appropriately selected.

[0072] Furthermore, when the first bone is one of a pair of left and right bones or one of a pair of left and right talus bones, the inverted shape generator 15 may horizontally invert one of the plurality of second shapes represented by each of the plurality of second information belonging to the first candidate group stored in the first storage unit 51 so as to align it with the other of the plurality of second shapes (third modified form). For example, when the first bone is on the right side, the inverted shape generator 15 horizontally inverts the left second shape so that it becomes the right second shape. This allows the first selection information to be selected efficiently.

[0073] In the above-described embodiment, the design support device 1000 may also include a deformed shape generation unit 16 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 1 (fourth modified embodiment). In this case, the input unit 2 receives input of a portion of the first bone. The deformed shape generation unit 16 generates one or more deformed second shapes by modifying the shape of the portion received by the input unit 2 for the second shape. This allows the generation of a deformed second shape by modifying a portion, and the generated deformed second shape can be used as a reference for designing an implant for the first bone, allowing for more appropriate selection of a reference implant. The deformed second shape may be generated for the second shape of the second information belonging to the first candidate group, or may be generated for the second shape of the second information belonging to the second candidate group, or may be generated for the second shape of the second information belonging to the second candidate group. The following description will be given taking the case where a deformed second shape is generated for the second shape of the second information belonging to the third candidate group as an example, but is not limited thereto.

[0074] FIG. 8 is a diagram illustrating the generation of a deformed shape as an example. FIG. 8A is a diagram illustrating the input of a region. FIG. 8B shows a second shape of second information belonging to a third candidate group before deformation. FIG. 8C shows a deformed second shape obtained by deforming the height of the region in the second shape shown in FIG. 8B to a first height. FIG. 8D shows a deformed second shape obtained by deforming the height of the region in the second shape shown in FIG. 8B to a second height higher than the first height. FIG. 8E shows a deformed second shape obtained by deforming the height of the region in the second shape shown in FIG. 8B to a third height higher than the second height ((first height)<(second height)<(third height)).

[0075] For example, the menu bar may include a "Transform" button for instructing generation of a deformed shape. The design support device 1000 may display the "Transform" button on the menu bar from the start of operation. The design support device 1000 may display the "Transform" button on the menu bar after selecting the third candidate group. Furthermore, the menu bar may not have a "Transform" button. In this case, the design support device 1000 may generate a deformed shape under predetermined conditions when selecting the third candidate group.

[0076] If the menu bar includes a "Transform" button, when the user operates the "Transform" button via the input unit 2, the design support device 1000 causes the deformed shape generation unit 16 to display a message on the selection result display screen prompting the user to select a second shape to be used as the source of the transformation from the third number of second shapes represented by each of the third number of second selection information.

[0077] The user inputs the selection of the second shape to be transformed into the design support device 1000 via the input unit 2. For example, the mouse cursor is positioned at the display position of the second shape that the user desires to transform, and the mouse is operated to input. Note that the second shape to be transformed may be appropriately set in advance, and its input may be omitted. For example, a second shape belonging to a third candidate group that satisfies a predetermined condition may be set as the second shape to be transformed.

[0078] Upon receiving an input operation to select a second shape to be transformed, the design support device 1000 displays, via the transformed shape generation unit 16, a message prompting the user to input the location, transformation method, transformation amount per transformation (transformation amount per transformation (unit transformation amount)), and the number of shapes to be generated. The selection result display screen includes input fields for inputting the transformation method, unit transformation amount, and number of shapes to be generated. The transformation method includes, for example, changing the parameter amount of the parameter (e.g., changing the width, the height, or the height). The user inputs the location, transformation method, unit transformation amount, and number of shapes to the design support device 1000 via the input unit 2. For example, as shown in FIG. 8A , the talus head PA of the talus is input as the location, a change in height is input as the transformation method, 0.1 mm is input as the unit transformation amount, and 3 is input as the number of shapes to be generated. Note that at least one of the transformation method, unit transformation amount, and number of shapes to be generated may be appropriately set in advance, and input thereof may be omitted. Upon receiving these inputs, the computer aided design device 1000 deforms the input portion by the input deformation method and the input unit deformation amount by the input number of generation units, thereby generating the input number of deformed second shapes, using the deformed shape generation unit 16. In the above example, the second shape SH20 is deformed to a talar head that is 0.1 mm higher than the height of the talar head of the original second shape SH20 shown in Fig. 8B to generate a deformed second shape SH21 shown in Fig. 8C, the second shape SH20 is deformed to a talar head that is 0.1 mm higher than the height of the talar head of the deformed second shape SH21 to generate a deformed second shape SH22 shown in Fig. 8D, and the second shape SH20 is deformed to a talar head that is 0.1 mm higher than the height of the talar head of the deformed second shape SH22 to generate a deformed second shape SH23 shown in Fig. 8E. Then, the design support device 1000 further displays the generated deformed second shape on the selection result display screen using the deformed shape generation unit 16, and stores fourth information (post-deformation second information) representing the generated deformed second shape in the memory unit 5.

[0079] The deformed shape generation unit 16 may further store, as one group, the second information of the second shape before the change and one or more pieces of deformed second information related to one or more deformed second shapes in the storage unit 5. In the example shown in FIG. 8 , the fourth information (first to third post-deformation second information) of the first to third deformed second shapes SH21 to SH23 shown in FIGS. 8C to 8E , respectively, is stored in the storage unit 5 in association with the second information (pre-deformation second information) of the second shape SH20 shown in FIG. 8B . More specifically, for example, the same group ID is assigned to the pre-deformation second information and the first to third post-deformation second information, and the pre-deformation second information and the first to third post-deformation second information are stored in the storage unit 5 in association with the same group ID. For example, the first to third post-deformation second information are stored in the third storage unit 53. Thus, when referring to the second shape selected as the third candidate group, the corresponding modified second information can be confirmed by referring to the associated group ID. Furthermore, for example, the first to third modified second information may be stored in the first storage unit 51.

[0080] In the above-described embodiment, the design support device 1000 may also include a cartilage-imparting shape generator 17 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 1 (fifth modified embodiment). When the first bone has cartilage, the cartilage-imparting shape generator 17 may generate a plurality of cartilage-imparting shapes by adding cartilage corresponding to the cartilage of the first bone to the second shape of the second information in the third candidate group selected by the second selection processing unit 13, with varying thicknesses, and may generate each of the fifth information (post-cartilage-imparting second information) for each of the generated cartilage-imparting shapes as a new element of the third candidate group. The fifth information may be generated for the second shape of the second information belonging to the first candidate group, for the second shape of the second information belonging to the second candidate group, or for the second shape of the second information belonging to the third candidate group. The following description will be given taking as an example a case where the fifth information is generated for the second shape of the second information belonging to the third candidate group, but is not limited thereto.

[0081] The cartilage-imparting shape generating unit 17 outputs these generated cartilage-imparting shapes to the output unit 3, together with a third number of second shapes (implants) represented by each of the third number of pieces of second selection information selected by the second selection processing unit 13. This makes it possible to generate a plurality of cartilage-imparting shapes with different cartilage thicknesses, and to use these generated cartilage-imparting shapes as reference for designing the first bone implant, allowing a more appropriate reference implant to be selected.

[0082] 9A and 9B are diagrams illustrating an example of generating a cartilage-added shape to which cartilage has been added. Fig. 9A shows a second shape of the second information belonging to the third candidate group before cartilage has been added, Fig. 9B shows a second shape obtained by adding cartilage of a first thickness to the second shape shown in Fig. 9A, Fig. 9C shows a second shape obtained by adding cartilage of a second thickness that is thicker than the first thickness to the second shape shown in Fig. 9A, and Fig. 9D shows a second shape obtained by adding cartilage of a third thickness that is thicker than the second thickness to the second shape shown in Fig. 9A ((first thickness)<second thickness)<third thickness)). Whether the first bone has cartilage is determined, and if the first bone has cartilage, for example, three first to third cartilage-imparted shapes SC1 to SC3 are generated by imparting three first to third cartilages CA1 to CA3 having different thicknesses to the second shape SH30 of the second information belonging to the third candidate group shown in FIG. 9A , as shown in FIGS. 9B to 9D , and each of the fifth information representing the generated first to third cartilage-imparted shapes SC1 to SC3 is generated. The second shape SH30 to impart cartilage may be selected by the user, for example, or may be selected randomly by the computer aided design system 1000. Alternatively, for example, all of the second shapes of the second information belonging to the third candidate group may be second shapes to impart cartilage.

[0083] The cartilage-imparting shape generation unit 17 may further store the plurality of fifth information as a single group in the storage unit 5 in association with the second information before the cartilage is imparted. In the example shown in FIG. 9 , the fifth information (first to third post-cartilage-imparting second information) of the first to third cartilage-imparting shapes SC1 to SC3 shown in FIGS. 9B to 9D , respectively, is stored in the storage unit 5 in association with the second information (pre-cartilage-imparting second information) of the second shape SH30 shown in FIG. 9A . More specifically, for example, the same group ID is assigned to the pre-cartilage-imparting second information and the first to third post-cartilage-imparting second information, and the pre-cartilage-imparting second information and the first to third post-cartilage-imparting second information are stored in the storage unit 5 in association with the same group ID. For example, the first to third post-cartilage-imparting second information are stored in the first storage unit 51.

[0084] In the above-described embodiment, the design support device 1000 may also include an enlarged / reduced shape generator 18 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 1 (sixth modified embodiment). The enlarged / reduced shape generator 18 calculates the distributions of a plurality of shape parameters for a plurality of second shapes in the plurality of second information pieces of the first candidate group. The enlarged / reduced shape generator 18 then generates one or more new second shapes by enlarging or reducing one second shape selected from the plurality of second shapes in the plurality of second information pieces of the first candidate group within respective ranges (enlargement / reduction ranges) based on the calculated distributions, and uses the second information pieces of the generated new second shapes as elements of the first candidate group, thereby increasing the number of elements in the first candidate group. That is, the enlarged / reduced shape generator 18 performs at least one of an enlargement process to enlarge the second shape and a reduction process to reduce the second shape. This increases the number of elements in the first candidate group. The expanded / contracted shape generating unit 18 generates the new second shapes for each of the increased numbers corresponding to the widths of the distributions obtained, thereby preventing the formation of new second shapes that deviate from the distributions and allowing the number of elements in the first candidate group to be increased appropriately.

[0085] 10A and 10B are diagrams illustrating an example of generating scaled shapes by scaling a shape. Fig. 10A shows the distributions of length, width, and height, and Fig. 10B shows two second shapes (first and second reduced shapes) obtained by scaling a second shape, the second shape before scaling (basic shape), and two second shapes (first and second enlarged shapes) obtained by scaling a second shape. The horizontal axis of Fig. 10A represents the classes of length, width, and height, and the vertical axis represents the frequency (count) of each class.

[0086] For example, the menu bar includes a "Scale" button for instructing scaling. When a user's input operation of the "Scale" button is accepted via the input unit 2, the scaled shape generation unit 18 obtains a distribution of each of the plurality of parameters, namely, vertical length, horizontal length, and height, for a plurality of second shapes in a plurality of pieces of second information stored in the first storage unit 51, as shown in FIG. 10A , for example. 10B, the enlarged / reduced shape generation unit 18 generates four new second shapes (first and second reduced shapes SH41A, SH41B and first and second enlarged shapes SH42A, SH42B) by enlarging or reducing a second shape (basic shape SH40) selected at random from the plurality of second shapes in the plurality of second information stored in the first storage unit 51, or a second shape (basic shape SH40) input and specified by the user via the input unit 2, within each of the enlargement / reduction ranges of −3σ to +3σ based on the determined vertical length, horizontal length, and height distributions, respectively. The σ is the standard deviation. For example, the first reduced shape SH41A is generated by reducing the length, width, and height of the basic shape SH40 to one-third, and the second reduced shape SH41B is generated by reducing the length, width, and height of the basic shape SH40 to two-thirds. The first enlarged shape SH42A is generated by enlarging the length, width, and height of the basic shape SH40 to four-thirds, and the second enlarged shape SH42B is generated by enlarging the length, width, and height of the basic shape SH40 to five-thirds. The enlarged / reduced shape generation unit 18 then stores each piece of information representing the generated first and second reduced shapes SH41A, SH41B and first and second enlarged shapes SH42A, SH42B in the first storage unit 51 as second information of the first candidate group, thereby increasing the number of elements in the first candidate group. When storing the information, the enlarged / reduced shape generation unit 18 may store each piece of information representing the first and second reduced shapes SH41A, SH41B and the first and second enlarged shapes SH42A, SH42B as a single group in the first storage unit 51, in association with the second information of the basic shape SH40, as described above.

[0087] Note that the example shown in FIG. 10 is merely an example and is not limited thereto. The scaling range may be any range, such as from −σ to +σ, the number of scaling parameters may be any number, such as 5 or 10, and the reduction and enlargement rates may be any number, such as 5% or 10%. The scaling range, the number of scaling parameters, the reduction rate, and the enlargement rate may be set appropriately in advance or by user input via the input unit 2. The number of scaling parameters may be set based on the standard deviation or coefficient of variation in the distribution of the parameter with the largest weight among the multiple parameters used in the weighted linear sum. The larger the standard deviation (the wider the distribution), the larger the number of scaling parameters to be set. The larger the coefficient of variation, the larger the number of scaling parameters to be set.

[0088] Furthermore, when scaling, the reduced shape and the enlarged shape may be generated by scaling the parameter with the largest weight among the plurality of parameters used in the weighted linear sum.

[0089] Although the scaling shape generation unit 18 scales the entire second shape in the above description, it may also scale one or more portions of the second shape. More specifically, the scaling shape generation unit 18 calculates a length distribution (e.g., vertical length distribution, horizontal length distribution, height distribution, etc.) of one or more portions of the second shape for the multiple second shapes in the multiple second information of the first candidate group, and generates one or more new second shapes by scaling one second shape selected from the multiple second shapes in the multiple second information of the first candidate group within one or more scaling ranges based on the calculated length distribution of the one or more portions. The second information of the generated new second shape is used as an element of the first candidate group, thereby increasing the number of elements in the first candidate group. The portion is set appropriately in advance or by user input via the input unit 2. This allows the number of elements in the first candidate group to be increased by focusing on a specific portion. In particular, by setting the affected area of ​​the affected bone as the above-mentioned location, the number of elements in the first candidate group, which expands or contracts the affected area, can be increased, and implants that can be used as a reference when designing the implant for the first bone can be more appropriately selected.

[0090] The expanded / contracted shape generator 18 may generate the new second shape for an increased number corresponding to the width of one of the length distributions obtained, or for each of a plurality of increased numbers corresponding to the widths of a plurality of length distributions. When there are a plurality of portions, the plurality of increased numbers may be set based on the standard deviation or coefficient of variation of the plurality of length distributions. The larger the standard deviation (the wider the distribution), the larger the increased number is set. The larger the coefficient of variation, the larger the increased number is set.

[0091] Furthermore, if the radius of curvature of a curved portion in a new second shape generated by the scaling is smaller than a minimum radius of curvature, the scaled shape generator 18 may deform the new second shape by replacing the radius of curvature with the minimum radius of curvature, and may set the deformed new second shape as an element of the first candidate group. This makes it possible to design an implant that satisfies a constraint on the radius of curvature in the manufacture of the implant.

[0092] 11A and 11B are diagrams illustrating an example of the replacement of the curvature radius. Fig. 11A shows the basic shape SH40, the first and second reduced shapes SH41A and SH41B, and the first and second expanded shapes SH42A and SH42B shown in Fig. 10B, which illustrate the curvature radius R, before the replacement of the curvature radius. Fig. 11B shows the shapes after the replacement of the curvature radius. For example, if the minimum curvature radius is R1.5, as shown in Fig. 11A, the first reduced shape SH41A has a curvature radius R1.0. Therefore, as shown in Fig. 11B, the first reduced shape SH41A is transformed into a first reduced shape SH41Aa in which the curvature radius R1.0 is replaced with the curvature radius R1.5. The second information representing this transformed first reduced shape SHAa is stored in the first storage unit 51 as an element of the first candidate group, in place of the second information representing the first reduced shape SHA.

[0093] In the above-described embodiment, the design support device 1000 may also include a parameter generation unit 19 functionally configured in the control processing unit 1, as indicated by the dashed line in FIG. 1 (seventh modified embodiment). The parameter generation unit 19 generates a plurality of shape-related parameters (third parameters) for the second shape of the implant based on a plurality of pieces of second information in the first candidate group, so that the number of new parameters (fourth parameters) is a predetermined number (fourth number) that is smaller than the number of the third parameters and different from the third parameters. For example, in the case of the talus, as shown in FIG. 2 , there are many third parameters, such as length, width, height, surface area, volume, normalized talar head radius, normalized talar trochlear width, normalized talar trochlear radius, talar trochlear angle, and talocalcanal joint angle. Therefore, by generating the fourth parameters using the parameter generation unit 19, the number of parameters can be reduced. Then, the parameter generation unit 19 sets multiple new data (new data points) represented by the fourth parameter so that they are evenly distributed within a predetermined range, calculates each value, and converts each value of the multiple new data represented by the fourth parameter into each value represented by the third parameter.

[0094] Fig. 12 is a diagram illustrating the generation of new parameters as an example. Fig. 13 is a diagram illustrating the conversion to distance as an example. Fig. 13A shows the case where the angle of a corner is converted to distance, and Fig. 13B shows the case where the radius of the curved surface of the corner is converted to distance.

[0095] More specifically, for example, the menu bar includes a "Parameter Generation" button for instructing the generation of new parameters. When the user presses the "Parameter Generation" button via the input unit 2, the parameter generation unit 19 first performs principal component analysis (PCA) using the plurality of second information items represented by the third parameters stored in the first storage unit 51. Next, the parameter generation unit 19 extracts, as fourth parameters, a fourth number of principal components from the plurality of principal components obtained by PCA, in descending order of contribution from the first principal component having the highest contribution rate. The fourth number is appropriately set in advance as an integer value, for example, any of 3 to 6. In one example, the fourth number is 3, and the first to third principal components are extracted as the fourth parameters. Next, the parameter generating unit 19 calculates the standard deviation σ of each of the extracted fourth parameters, calculates a setting range for new data for the fourth parameter based on the calculated standard deviation σ, and uniformly sets a predetermined number (fifth number) of points (new data points) NPn within the calculated setting range, for example, as shown in FIG. 12 . The setting range may be, for example, −2σ (=−2×σ) to +2σ or −3σ (=−3×σ) to +3σ. The fifth number is set as appropriate in advance. Note that, although a fifth number of new data points is set here, the interval between the new data points may also be set as appropriate in advance. In one example, when the first, second, and third principal components are extracted as the fourth parameters and the fifth number is six, new data points NP11 to NP16 are set for the first principal component, new data points NP21 to NP26 are set for the second principal component, and new data points NP31 to NP36 are set for the third principal component. In an xyz orthogonal coordinate space with the first, second, and third principal components as the x, y, and z axes, six new data points (NP11, NP21, NP31), (NP12, NP22, NP32), ..., (NP16, NP26, NP36) are set. Note that FIG. 12 illustrates the setting range and new data points NP11 to NP16 for the first principal component.Next, the parameter generating unit 19 performs an inverse PCA transformation on the value of the fourth parameter for each new data point to determine the value of the third parameter. Then, the parameter generating unit 19 stores the determined value of the third parameter in the storage unit 5 as the value of the third parameter after new parameters are generated. Note that, instead of the first candidate group stored in the first storage unit 51, a first candidate group including a first shape having the value of the third parameter determined by the parameter generating unit 19 may be stored in the first storage unit 51 as a new first candidate group.

[0096] Principal component analysis may be performed using covariance without standardizing the third parameter. In this case, the dimensions of each third parameter are unified. For example, the dimensions are unified to distance [mm]. In this case, the angle θ of the corner is converted to (sin θ, cos θ) of a unit circle with a radius of 1 [mm], as shown in FIG. 13A, and the dimensions are unified to distance [mm]. Alternatively, for example, if the height is h, it is converted to h × tan θ, and the dimensions are unified to distance [mm]. As shown in FIG. 13B, when the curved surface R is sandwiched between two planes of the second shape, the radius of the curved surface R at the corner is converted to the distance LG from the intersection PT12 of the cross-sectional lines of the two planes (first cross-sectional line LN1, second cross-sectional line LN2) to the vertex of the curved surface R in the cross section, and the dimensions are unified to distance [mm]. This conversion is performed because the volume change of the radius of the curved surface R is large relative to the change in its value.

[0097] 1 , the design support device 1000 may include a shape optimization unit 20 functionally configured in the control processing unit 1 (eighth modified embodiment). The shape optimization unit 20 optimizes the second shape of the implant that is the target of optimization (second shape to be optimized) to the first shape of the body part that is received as first information by the input unit 2, with respect to one or more parameters (parameters to be optimized) among a plurality of shape-related parameters in the second shape of the implant.

[0098] The parameters to be optimized are input by, for example, a user (operator) through the input unit 2. Alternatively, for example, for a plurality of pieces of second information stored in the first storage unit 51, a variance (e.g., standard deviation) is calculated for each parameter, and the parameter with the largest variance is set as the parameter to be optimized. In this case, for example, a parameter with the largest variance is set as the parameter to be optimized. Alternatively, for example, a predetermined number (sixth number) of parameters in descending order of variance are set as the parameters to be optimized. The sixth number may be set appropriately in advance, or may be input by the user through the input unit 2. Alternatively, for example, a difference is calculated for each parameter between the second shape to be optimized and the first shape of the body part accepted by the input unit 2 as first information, and the parameter with the largest difference is set as the parameter to be optimized. In this case, for example, a parameter with the largest difference is set as the parameter to be optimized. Alternatively, for example, a predetermined number (seventh number) of parameters in descending order of difference are set as the parameters to be optimized. The seventh number may be set as appropriate in advance, or may be input by the user via the input unit 2. The difference in parameters between the second shape to be optimized and the first shape of the body part accepted as the first information by the input unit 2 is calculated, for example, by finding, for a shape related to the parameters, a plurality of corresponding points (nearest points) between the second shape to be optimized and the first shape of the body part accepted as the first information by the input unit 2, and calculating the RMSE of the distances (Euclidean distances) between the found corresponding points as the difference.

[0099] The second shape to be optimized is, for example, input by a user (operator) through the input unit 2. Alternatively, for example, the second shape to be optimized is selected from a third candidate group through an input operation by the user through the input unit 2. Alternatively, for example, the second shape to be optimized is set to be ranked first in the third candidate group and is automatically optimized.

[0100] More specifically, for example, the menu bar includes a "Shape Optimization" button for instructing optimization of the second shape. When the user's input operation of the "Shape Optimization" button is accepted via the input unit 2, the shape optimization unit 20 first determines a plurality of corresponding points between the second shape to be optimized and the reference shape, using the second shape to be optimized as an initial value, and then determines the RMSE of the Euclidean distances between the corresponding points for the determined plurality of corresponding points as the shape difference (initial second shape difference) between the second shape to be optimized and the reference shape. Next, the shape optimization unit 20 executes a second shape update process in which a new current second shape is generated by changing the current values ​​of the parameters to be optimized by a predetermined value (change interval value). The change interval value is set in advance as appropriate for each parameter of the second shape. Next, the shape optimization unit 20 performs a second shape difference process to determine a plurality of corresponding points between the current second shape and the reference shape, and calculates the RMSE of the Euclidean distances between the determined corresponding points as the shape difference (current second shape difference) between the current second shape and the reference shape. Next, the shape optimization unit 20 performs a determination process to determine whether a minimum second shape has been found based on the second shape differences (initial second shape differences and each current second shape difference) determined so far. The shape optimization unit 20 determines that a minimum second shape has been found, for example, when the second shape difference changes from decreasing to increasing. If the result of the determination indicates that a minimum second shape has not been found, the shape optimization unit 20 sequentially repeats the second shape update process, the second shape difference process, and the determination process until it determines that a minimum second shape has been found. If there is one parameter to be optimized, the above-mentioned process is performed for that one parameter to be optimized, and if there are multiple parameters to be optimized, the above-mentioned process is performed for each parameter to be optimized, one by one.

[0101] Note that multiple parameters to be optimized may be optimized simultaneously. For example, while changing the combination of values ​​of the multiple parameters to be optimized, a search is performed for combinations of values ​​of the multiple parameters to be optimized until the second shape difference changes from decreasing to increasing.

[0102] Fig. 14 is a diagram illustrating an example of optimization of the second shape. In one example, when optimizing the lateral protrusion of the talus shown on the left side of Fig. 14, the second shape update process, the second shape difference process, and the determination process are repeated, and as shown in the center of Fig. 14, the second shape difference (RMSE) is calculated for each second shape in the order of 1.5, 1.4, 1.3, and 1.4. Since the RMSE changes from 1.3 to 1.4, which indicates an increase from a decrease, the second shape corresponding to the smallest second shape difference (RMSE) of 1.3 is determined as the optimal shape of the talus implant, as shown on the right side of Fig. 14.

[0103] In the above-described embodiment, the design support device 1000 may also include a difference calculation and display unit 21 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 1 (ninth modified embodiment). The difference calculation and display unit 21 calculates the difference (shape difference) between multiple shapes of the same type in a body part and displays the calculated difference (shape difference) on the output unit 3. In this case, the output unit 3 is configured with a display device. The multiple shapes of the same type may be, for example, a first shape of the body part, or a second shape of an implant, or may be, for example, the first shape of the body part and the second shape of an implant. In calculating the shape difference between multiple shapes of the same type, one shape among the multiple shapes is set as a reference shape, and for each of the remaining shapes, the difference between that shape and the reference shape is calculated as the shape difference of that shape. Note that if there are two multiple shapes and the distance between nearest points is used as the shape difference, as described below, setting a basic shape is not necessary.

[0104] 15A and 15B are diagrams illustrating an example of how the difference amount is displayed, in which Fig. 15A shows a talus (first shape) and Fig. 15B shows an implant (second shape) of the talus model shown in Fig. 15A.

[0105] In the example shown in Figure 15, the amount of shape difference between the first shape BP1 of the human talus shown in Figure 15A and the second shape BP2 of the implant talus shown in Figure 15B is calculated, and this calculated amount of shape difference is displayed on the output unit 3 of the display device.

[0106] More specifically, for example, the menu bar includes a "Difference Calculation Display" button for instructing calculation and display of the shape difference amount. When the user presses the "Difference Calculation Display" button via the input unit 2, the difference calculation and display unit 21 first outputs to the output unit 3 a message prompting the user to determine multiple shapes to be calculated and displayed. The user inputs first information about the first shape BP1 via the input unit 2 and second information about the second shape BP2 via the input unit 2. Upon receiving the input of the shapes BP1 and BP2, the difference calculation and display unit 21 aligns the first shape BP1 and the second shape BP2 using a known ICP algorithm, and for each point in the second point cloud data of the second shape BP2, searches for the nearest point in the first point cloud data of the first shape BP1 that has the shortest Euclidean distance to that point as a corresponding point, and calculates the Euclidean distance between the searched corresponding points as the shape difference amount of the point. Then, the difference calculation and display unit 21 displays each point of the second point cloud data of the second shape BP2 on the output unit 3 with a brightness value corresponding to the shape difference amount of the point. For example, the possible range of the shape difference amount is divided into eight ranges, and the shape difference amount is displayed on a gray scale with eight gradations. This allows the finish of the implant to be visually confirmed, and improves the visibility of the trim position.

[0107] In the above description, the second information regarding the second shape BP1 and the first information regarding the first shape BP2 are input from the input unit 2, but they may be selected, for example, from the second information and the first information stored in the memory unit 5, or may be selected, for example, from a third group of candidates, and the first shape BP2 corresponding to this selected second shape BP1 is searched for and selected from the memory unit 5.

[0108] This application is based on Japanese Patent Application No. 2024-105191 filed on June 28, 2024, the contents of which are incorporated herein by reference.

[0109] In order to express the present invention, the present invention has been properly and sufficiently described above through the embodiments with reference to the drawings, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims.

[0110] REFERENCE SIGNS LIST 1000 Design support device 1 Control processing unit 2 Input unit 3 Output unit 4 Interface unit (IF unit) 5 Storage unit 11 Control unit 12 First selection processing unit 13 Second selection processing unit 14 Data number increase / decrease unit 15 Inverted shape generation unit 16 Deformed shape generation unit 17 Cartilage-added shape generation unit 18 Enlarged / reduced shape generation unit 19 Parameter modification unit 20 Shape optimization unit 21 Difference calculation / display unit

Claims

1. A design support system comprising: an input unit that accepts input of first information regarding a first shape of a body part; a first selection processing unit that selects, from a first candidate group including a plurality of pieces of second information regarding a second shape of an implant, a plurality of pieces of second information that satisfy a first condition in relation to the first information as a second candidate group; and a second selection processing unit that selects, from at least some of the second information included in the second candidate group, a piece of second information that satisfies a second condition different from the first condition as a third candidate group, wherein the second selection processing unit further associates order information regarding the order in the second condition with the second information.

2. The design support system of claim 1, wherein the first condition is that the volume difference between the first shape and the second shape of the second information that is an element of the first candidate group is equal to or less than a predetermined first threshold, and the first selection processing unit determines that the second shape satisfies the first condition if the volume difference is equal to or less than the first threshold, and selects the second information of the determined second shape as an element of the second candidate group.

3. The design support system of claim 1, wherein the first condition is that the dimensional product obtained by multiplying the vertical difference, horizontal difference, and height difference between the first shape and the second shape of second information that is an element of the first candidate group is equal to or less than a predetermined second threshold, and the first selection processing unit determines that the second shape satisfies the first condition if the dimensional product is equal to or less than the second threshold, and selects the second information of the determined second shape as an element of the second candidate group.

4. A design support system according to any one of claims 1 to 3, wherein the second condition is that the shape difference between the first shape and the second shape is within a predetermined number in ascending order, and the order in the second condition is the order of the size of the shape difference.

5. The design support system according to claim 4, wherein the second selection processing unit determines a plurality of corresponding points between the first shape and the second shape, and determines the root mean square error of the distance between the determined plurality of corresponding points as the shape difference.

6. The design support system of claim 4, wherein the second selection processing unit: determines the difference between the value of one shape-related parameter in the second shape and the value of the parameter in the first shape as the shape difference; or determines each difference between each value of multiple shape-related parameters in the second shape and each value of the multiple parameters in the first shape, and determines the shape difference as a linear sum or a weighted linear sum of each of the differences.

7. The design support system of claim 4, wherein the second selection processing unit determines a plurality of corresponding points between the first shape and the second shape, and determines the root mean square error of the distance between the determined plurality of corresponding points, determines the difference between the value of one shape-related parameter in the second shape and the value of the parameter in the first shape, and determines the linear sum or weighted linear sum of the determined root mean square error and the determined difference as the shape difference, or determines each difference between each value of a plurality of shape-related parameters in the second shape and each value of the plurality of parameters in the first shape, and determines the linear sum or weighted linear sum of the determined root mean square error and each determined difference as the shape difference.

8. The design support system according to claim 6 or 7, wherein the value of each of the plurality of parameters changes independently of changes in the values ​​of the other parameters.

9. The design support system according to claim 8, wherein the weights for the plurality of parameters in the weighted linear sum are set based on the distribution of the parameter values.

10. The first information is represented by first point cloud data representing the first shape, and the second information is represented by second point cloud data representing the second shape, the input unit further receives an input of a first region to be set on the implant, and the device further comprises a data number increasing / decreasing unit that performs at least one of a thinning process that generates second point cloud data of second information of a new second candidate group and first point cloud data of new first information by thinning out the second point cloud data in the first region in the second shape and the first point cloud data in the second region corresponding to the first region in the first shape, and an interpolation process that generates second point cloud data of second information of a new second candidate group and first point cloud data of new first information by interpolating and increasing the second point cloud data in the first region in the second shape and the first point cloud data in the second region corresponding to the first region in the first shape, 10. The design support system according to claim 1, wherein the second selection processing unit selects the third group of candidates using second point cloud data of second information of the new second group of candidates generated by the data number increasing / decreasing unit and first point cloud data of new first information.

11. The design support system according to any one of claims 1 to 10, wherein the implants are a pair of left and right bone implants or a talus implant.

12. A design support system according to any one of claims 1 to 11, wherein the part of the body is a first bone, the first bone is one of a pair of left and right bones or one of a pair of left and right taluses, the input unit further receives input of third information regarding a third shape of the other second bone of the pair of left and right bones or third information regarding the third shape of the other second bone of the pair of left and right taluses, and further comprises an inverted shape generation unit that generates a shape obtained by left and right inverting the third shape of the third information received by the input unit as a first shape to be used in the first selection processing unit.

13. A design support system as described in any one of claims 1 to 11, wherein the part of the body is a first bone, the input unit further receives input of a part of the first bone, and the system further comprises a deformed shape generation unit that generates one or more deformed second shapes by changing the shape of the part received by the input unit in the second shape of second information that is an element of the third candidate group.

14. The design support system according to claim 13, further comprising a storage unit, wherein the deformed shape generation unit further stores, in the storage unit, second information on the second shape before the change and one or more pieces of deformed second information relating to one or more deformed second shapes as one group.

15. A design support system as claimed in any one of claims 1 to 11, further comprising a cartilage-imparting shape generation unit that, if the body part is a first bone and the first bone has cartilage, generates a plurality of cartilage-imparting shapes by adding cartilage of varying thicknesses corresponding to the cartilage of the first bone to the second shape of the second information in the third candidate group selected by the second selection processing unit, and generates each piece of fifth information relating to each of the generated plurality of cartilage-imparting shapes as an element of a new third candidate group.

16. A design support system as described in claim 15, further comprising a memory unit, wherein the cartilage-imparting shape generation unit further stores the plurality of fifth information in the memory unit as one group in association with the second information before the cartilage is imparted.

17. A design support system as claimed in any one of claims 1 to 16, further comprising an enlarged / contracted shape generation unit that calculates the distribution of each of a plurality of shape-related parameters for a plurality of second shapes in a plurality of pieces of second information in the first candidate group, generates one or more new second shapes by enlarging or reducing one second shape selected from a plurality of second shapes in a plurality of pieces of second information in the first candidate group within a range based on each of the calculated distributions, and increases the number of elements in the first candidate group by making the second information of the generated new second shapes an element of the first candidate group.

18. The design support system according to claim 17, wherein the enlarged / reduced shape generation unit generates the new second shape for each increased number corresponding to each width of each distribution obtained.

19. A design support system as described in any one of claims 1 to 16, further comprising an enlarged / contracted shape generation unit that, for a plurality of second shapes in a plurality of pieces of second information in the first candidate group, determines a length distribution of one or more portions in the second shapes, generates one or more new second shapes by enlarging or contracting one second shape selected from the plurality of second shapes in the plurality of pieces of second information in the first candidate group within one or more enlargement / contraction ranges based on the determined length distribution of one or more portions, and increases the number of elements in the first candidate group by making the second information of the generated new second shapes an element of the first candidate group.

20. The design support system according to claim 19, wherein the enlarged / reduced shape generation unit generates the new second shape for an increased number corresponding to the width of one of the length distributions obtained, or for each of a plurality of increased numbers corresponding to the width of each of a plurality of length distributions.

21. The design support system according to claim 20, wherein, when there are a plurality of said portions, said plurality of increased numbers are set based on the standard deviation or the coefficient of variation in said plurality of length distributions, respectively.

22. A design support system as described in claim 17 or claim 19, wherein the enlarged / reduced shape generation unit further deforms the new second shape by replacing the radius of curvature of a curved portion in the new second shape with the minimum radius of curvature if the radius of curvature is smaller than the minimum radius of curvature, and sets the deformed new second shape as an element of the first candidate group.

23. A design support method comprising: an input step of accepting input of first information regarding a first shape of a body part; a first selection processing step of selecting, from a first candidate group including a plurality of pieces of second information regarding a second shape of an implant, a plurality of pieces of second information that satisfy a first condition in relation to the first information as a second candidate group; and a second selection processing step of selecting, from at least some of the second information included in the second candidate group, the second information that satisfies a second condition different from the first condition as a third candidate group, wherein the second selection processing step further associates order information regarding the order in the second condition with the second information.

24. A design support program that causes a computer to function as the design support system according to any one of claims 1 to 21.

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