WO2026005021A1 - Design assistance system, design assistance method, and design assistance program - Google Patents

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

The present invention relates to a design support system, design support method, and design support program that support implant design.

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

Special Publication No. 2022-509995

A design support system, design support method, and 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 that satisfies a second condition different from the first condition.

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

1 is a block diagram showing a configuration of a design support system according to an embodiment. FIG. 10 is a diagram illustrating parameters related to a shape, as an example. 10A and 10B are diagrams illustrating an example of an increase or decrease in the number of points in a first region and point cloud data. FIG. 10 is a diagram illustrating an example of output of a selection result. 3 is a flowchart illustrating an operation of the design support apparatus according to the embodiment. FIG. 10 is a diagram illustrating, as an example, grouping of a plurality of pieces of second information belonging to a first candidate group. FIG. 10 is a diagram illustrating generation of an inverted shape as an example. FIG. 10 is a diagram illustrating generation of a deformed shape as an example. FIG. 10 is a diagram illustrating the generation of a cartilage-imparted shape to which cartilage is imparted, as an example. 10A and 10B are diagrams illustrating generation of an enlarged or reduced shape by enlarging or reducing a shape, as an example. FIG. 10 is a diagram illustrating, as an example, replacement of a radius of curvature. FIG. 10 is a diagram illustrating the generation of new parameters as an example. FIG. 10 is a diagram illustrating conversion into distance as an example. FIG. 10 is a diagram for explaining optimization of a second shape as an example. FIG. 10 is a diagram illustrating an example of how to display a difference amount.

One or more embodiments of the present invention will be described below with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. Components with the same reference numerals in each drawing are identical components, and their description will be omitted where appropriate. In this specification, generic reference numerals are used without subscripts to refer to components, and subscripted reference numerals are used to refer to individual components.

In recent years, there has been a demand for an implant design support system, implant design support method, and implant design support program that can efficiently select useful implants. Accordingly, the design support system in this 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 related to a first shape of a body part. The first selection processing unit selects, from a first candidate group containing multiple pieces of second information related to the second shape of the implant, multiple 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 related to the order in the second condition with the second information.

The following provides a more detailed explanation of such a design support system, as well as the design support method and design support program implemented therein. 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 types of arithmetic processing, and one or more database devices that store (manage) various types of data. Furthermore, at least some of these input/output terminal devices, one or more arithmetic processing devices, and one or more database devices may be integrated and interconnected to enable communication with the remainder. Here, the design support system will be explained using an example of a fully integrated design support device. The implant design support program may be recorded on a non-transitory recording medium, for example, or downloaded via a network, for example.

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 illustrating, as an example, shape-related parameters. FIGS. 2A to 2D show the parameters of the first to fourth aspects. FIG. 3 is a diagram illustrating, as an example, the first region and the increase or decrease in the number of points in the point cloud data. FIG. 4 is a diagram illustrating, as an example, the output of the selection results.

The design support system (design support device, as an example) 1000 in this 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.

The input unit 2 is connected to the control processing unit 1 and is a device that inputs various data necessary to operate the design support device 1000, such as various commands, such as a command to start implant design support, first information about the shape of a body part (first shape), the name of the implant, and the area to be set for the implant (first area). The input unit 2 may include, for example, a keyboard, a mouse, and multiple input switches to which predetermined functions are assigned.

The implants are medical devices or components that are implanted into the body of an animal (including humans), such as implants for bones, joints, cartilage, muscles, and tooth roots. The implants may be implants for the skull, tooth roots, ossicles, spine, sternum, ribs, clavicle, humerus, radius, ulna, carpal bones, metacarpals, phalanges, ilium, femur, patella, tibia, fibula, tarsus, metatarsals, phalanges, temporomandibular joint, hip joint, knee joint, and talus. The implants may be implants for a pair of parts of the animal's body, one on 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 in a part of the skull (parietal bone, temporal bone, nasal bone, lacrimal bone, maxilla, and cheekbone), tooth root, auditory ossicles, rib, clavicle, humerus, radius, ulna, carpal bones, metacarpal bones, phalanges, hip bone, femur, patella, tibia, fibula, tarsal bones, metatarsal bones, phalanges, temporomandibular joint, hip joint, knee joint, or talus.

The body part may be at least a part of an animal's (including a human's) bone, cartilage, muscle, or artificial dental root. Furthermore, the body part may be, for example, one of the pair of left and right parts. If the body part is a bone, the first region may be one of the pair of left and right bones.

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. Examples of such devices include display devices such as CRT displays (cathode ray tube displays), LCDs (liquid crystal displays), and organic photoluminescence displays, as well as printing devices such as printers.

The input unit 2 and output unit 3 may be configured as a touch panel. In this touch panel configuration, the input unit 2 is a position input device, such as a resistive or capacitive type, that detects and inputs an operation 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 the display position showing 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 users to intuitively understand input operations, providing a design support device 1000 that is easy for users to use.

The IF unit 4 is connected to the control processing unit 1 and is a circuit that, for example, inputs and outputs data to and from external devices under the control of the control processing unit 1. For example, it may be an interface circuit using the serial communication method RS-232C, 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 communications interface circuit that sends and receives communications signals to and from external devices, such as a data communications card or a communications interface circuit conforming to the IEEE 802.11 standard.

The memory unit 5 is connected to the control processing unit 1 and is a circuit that stores various specified programs and various specified data in accordance with the control of the control processing unit 1.

The various predetermined programs include, for example, a control processing program, which includes, for example, a control program, a first selection processing program, a second selection processing program, and a data count increase/decrease program. The control program is a program that controls each of the components 2 to 5 of the design support device 1000 according to the function of each component. The first selection processing program is a program that selects, from a first candidate group containing a plurality of pieces of second information related to the implant shape (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 count increase/decrease program is a program that executes at least one of thinning processing and interpolation processing.

The various types of 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, all of which are data necessary to execute each of these programs.

Such a storage unit 5 may include, for example, a non-volatile storage element such as ROM (Read Only Memory) or a rewritable non-volatile storage element such as EEPROM (Electrically Erasable Programmable Read Only Memory). The storage unit 5 also includes RAM (Random Access Memory), which serves as the working memory of the control processing unit 1 and stores data generated during execution of the specified program. The storage unit 5 may also be configured with a hard disk drive (HDD) or solid state drive (SSD) with a relatively large storage capacity.

The memory unit 5 functionally comprises 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.

The first shape and second shape may each be represented by solid data, or by point cloud data (three-dimensional coordinate values) representing their surface shapes (external contour shapes). In this embodiment, we will describe a case where the first shape and second shape are represented by point cloud data, but this is not limited to this.

In generating the point cloud data of the first shape (first point cloud data), for example, solid data of the body part is generated based on image data of the body part using a known method, and 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 in the same manner as 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 parameter generation unit 19 described below.

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

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

The control unit 11 controls each of the units 2 to 5 of the design support device 1000 according to the function of each unit, and is responsible for overall control of the design support device 1000.

The first selection processing unit 12 selects, from a first candidate group containing 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 from the perspective of the first condition to determine whether the first condition is satisfied, 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, for example, be 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.

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 less than or equal to a predetermined threshold (first threshold). In this case, if the volume difference is less than or equal to 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 belonging to the first candidate group, a second number of second information is selected as first selected information from the perspective of the first condition, and becomes an element of the second candidate group. 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 makes it possible to determine whether the second shape is similar to the first shape based on the volume difference.

Alternatively, for example, the first condition is that the dimensional product obtained by multiplying the length difference, width difference, and height difference between the first shape and a second shape that is an element of the first candidate group is less than or equal to a predetermined threshold (second threshold). In this case, if the dimensional product is less than or equal to 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 set 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 length difference, width difference, and height difference are calculated to determine the dimensional product. In other words, three linearly independent directions are set, and the differences in each of these three directions are calculated as the length difference, width difference, and height difference to determine the dimensional product. The second threshold is set in advance as appropriate from, for example, multiple samples. As a result, from the first number of second information belonging to the first candidate group, a second number of second information is selected as first selected information from the viewpoint of the first condition, and is set as an element of the second candidate group. 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 makes it possible to determine whether the second shape is similar to the first shape based on the product of dimensions.

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 made elements of the third candidate group. 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) that is 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 order of smallest to largest. 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 the user (designer) will refer to when designing an implant for the subject's first bone, and so may be set to a small number, such as three or five. This allows a second shape that is less different from the first shape to be selected, making it possible to select an implant that is more useful when designing an implant for the first bone.

The second selection processing unit 13 further associates order information relating to 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. As a result, when the second shapes represented by each piece of second selection information in the third candidate group are output to the output unit 3, the second shapes can be output in order based on the order information. This allows the user to select the reference implant by taking the order into consideration.

The shape difference can take any of the following five forms:

For example, the second selection processing unit 13 determines a plurality of corresponding points between the first shape and the second shape, and calculates 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, the second selection processing unit 13 may calculate the MSE (Mean Squared Error) of the distance (Euclidean distance) between the corresponding points as the shape difference, or may calculate the coefficient of determination ^R2 as the shape difference. In searching for the corresponding points, for example, the first shape and the second shape are aligned using a known ICP (Iterative Close Point) algorithm, and for each point in the first point cloud data of the first shape, the point (nearest point) with 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 finding a rotation matrix and a translation matrix that allow two shapes to be most closely overlapped.

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 that parameter in the first shape (second type of shape difference). The parameter is set appropriately 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.

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 weighted linear sum of the differences (third type of shape difference). The plurality of parameters are set appropriately in advance. When multiple parameters are set in this way, 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 features 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.

As shown in Figure 2A, the multiple parameters are, for example, the width, which is the length of the bone in the first direction, the length, which is the length of the bone in the second direction, and the height, which is the length of the bone in the third direction, which are orthogonal to each other (parameters of the first aspect). Figures 2A to 2D schematically illustrate one of a pair of tali, left and right, as an example of the bone.

The multiple parameters are, for example, the bone volume and bone surface area (parameters of the second aspect), as shown in Figure 2B.

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).

The multiple parameters are, for example, the talotrochlear angle and the talocalcaneal joint angle (parameters of the fourth aspect), as shown in Figure 2D.

The multiple parameters may be, for example, all or some of the parameters of the first to fourth aspects.

The independence of each parameter is determined, for example, based on the correlation coefficient R (or coefficient of determination ^R2 , 0≦ ^R2 ≦1) between the parameters of the multiple second shapes represented by each of the multiple pieces of second information belonging to the first candidate group. If the coefficient of determination ^R2 between two parameters is equal to or less than a predetermined threshold (independence determination threshold, for example, 0.7 or 0.6), the two parameters are determined to be independent. If the coefficient of determination ^R2 exceeds the independence determination threshold, the two parameters are determined to be not independent, i.e., dependent. More specifically, two parameters are selected from the multiple parameters, and whether or not they are independent is determined. This process is repeated until two independent parameters are selected. When two independent parameters are selected, one of the two parameters is selected, and an independent parameter is selected from the multiple parameters excluding the selected parameter for that selected parameter. In this way, independent parameters are selected from the multiple parameters.

Alternatively, for example, the independence of each parameter is determined by principal component analysis. More specifically, principal component analysis is performed on the multiple parameters, a predetermined number of principal components are selected from the first principal component, and the independent principal components are set as the independent parameters. For example, if the first bone and the implant are a specific bone, such as the talus, then for each parameter of the first aspect, the vertical length is independent, and the horizontal length and the height are each dependent on the vertical length.

Each weight for the multiple parameters in the weighted linear sum is set based on the distribution of the 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 to be, 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, if 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 (CV1/(CV1+CV2))×w, and the weight W2 of the second parameter is (CV2/(CV1+CV2))×w, where w is an appropriate value set in advance. Alternatively, for example, the weights are set based on the standard deviations and coefficients of variation of the parameters for multiple second shapes in the first candidate group. In one example, the weight W1 of the first parameter is (σ1/(σ1+σ2))×(CV1/(CV1+CV2))×w, and the weight W2 of the second parameter is (σ2/(σ1+σ2))×(CV1/(CV1+CV2))×w.

Alternatively, for example, the second selection processing unit 13 determines a plurality of corresponding points between the first shape and the second shape, calculates the root mean square error of the distance between the determined corresponding points, calculates 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 calculates 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).

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

The data number increase/decrease unit 14 performs at least one of thinning processing and interpolation processing.

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 corresponding to the first region in the first shape. 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 is performed. When thinning processing for the second shape is performed on the second candidate group, thinning processing for the first shape may be performed after the first selection processing and before the second selection processing. The following describes a case where thinning processing for the second shape is performed on the second candidate group, but this is not limited to this.

For example, as shown in FIG. 3, a first selected shape GE1 is displayed on the output unit 3, two points PT1 and PT2 are input and specified from the input unit 2, and a rectangular shape with a diagonal line having these specified two points PT1 and PT2 as its two end points is defined as the first area AR1. Next, points are sampled at a preset point interval from the point cloud data within the first area AR1 in the second shape GE1 represented by the first selection information, and this is defined 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 area in the first shape, and this is defined as point cloud data for a new first shape. For example, points are sampled every two or three points. The first area may be a pre-defined area.

The interpolation process generates second point cloud data of the second information of a new second candidate group and first point cloud data of the 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 the 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. The following describes a case where interpolation processing for the second shape is performed on the second candidate group, 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 that is set in advance. The third region may be a region different from the first region.

Then, the second selection processing unit 13 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 increase/decrease 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, allowing 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.

Then, the control unit 11 outputs to the output unit 3 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. 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, if 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.

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

Next, the operation of this embodiment will be described. Figure 5 is a flowchart showing the operation of the design support device in this embodiment.

When the design support device 1000 configured as described above is powered on, it initializes the necessary components and begins operation. The control processing unit 1 functionally configures a control unit 11, a first selection processing unit 12, a second selection processing unit 13, and a data number increase/decrease unit 14 by executing a control processing program. When the design support device 1000 begins 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.

When the user (operator) presses the "Start Assistance" button via the input unit 2, the design support device 1000 receives input of first information regarding the first shape of the subject's first bone via the control unit 11 of the control processing unit 1 (S1). Here, as an example, the body part is described as the subject's first bone, but this is not limited to this. 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 the 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 the first memory unit 51 of the memory unit 5 stores a plurality of second information items belonging to the first candidate group.

Next, the design support device 1000 causes the first selection processing unit 12 of the control processing unit 1 to select, as a second candidate group, multiple pieces of second information that satisfy the first condition from the first candidate group stored in the first storage unit 51, and stores the second information (first selection information) of this selected second candidate group in the second storage unit 52 (S2).

The design support device 1000 then uses the data count adjuster 14 of the control processing unit 1 to determine whether to increase or decrease the number of data points in the point cloud data (S3). For example, the data count adjuster 14 displays a data count increase/decrease inquiry screen on the output unit 3 to inquire about increasing or decreasing the number of data points. This data count increase/decrease inquiry screen includes, for example, an inquiry message display area that displays the inquiry message "Do you want to increase or decrease the number of data points?", an area input area that displays the implant and is used to input the first or 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.

When the user wishes to increase the number of data items, they input the third area AR1 using the area input area and press the "Increase" button. In this case, the data number increase/decrease unit 14 determines that the number of data items 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.

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

If the user does not want to increase or decrease the number of data items, they press the "Do Not 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 above determination, and then executes process S5.

In process S5, the design support 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 this 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.

Then, the design support device 1000 causes the control unit 11 of the control processing unit 1 to output 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 ends this process. Note that the control unit 11 may output the second selection information to an external device via the IF unit 4 as necessary.

As explained above, the design support device 1000 and the design support method and program implemented therein in the embodiment select second information from the second information belonging to the first candidate group in two stages, under both the first and second conditions, thereby efficiently selecting implants that can be used as reference when designing an implant for the first bone.

In the above-described embodiment, the multiple pieces of second information belonging to the first candidate group may be divided into multiple groups based on the distribution of shape-related parameters in the second shape, and each group may be stored in the first storage unit 51 in association with a group ID (first variant). 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 when designing an implant for the first bone.

FIG. 6 is a diagram illustrating, as an example, the grouping of 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 FIGS. 6A and 6B represent the class of the parameter, and the vertical axes represent the frequency (number).

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 midway between the two peaks PK11 and PK12, and are divided into second information of the first A group G1A having parameter values within the first A range from 0 to the parameter value PV11, and second information of the first B group G1B within the first B range that exceeds the parameter value PV11. Alternatively, for example, if the frequency distribution of a parameter in multiple second shapes represented by multiple pieces of second information has three peaks PK21, PK22, and PK23 as shown in FIG. 6B, the multiple pieces of second information are divided by the parameter value PV21, which is intermediate between the two peaks PK21 and PK22, and the parameter value PV22, which is intermediate between the two peaks PK22 and PK23, and are divided into second information of a secondA group G2A having parameter values within the secondA range from 0 to parameter value PV21, second information of a secondB group G2B having parameter values within the secondB range from parameter value PV21 to parameter value PV22, and second information of a secondC group G2C within the secondC range exceeding parameter value PV23.

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 values of the first shape, and then selects first selection information from the second information belonging to the selected group, thereby generating a second candidate group.

Furthermore, in the above-described embodiment, the design support device 1000 may include an inverted shape generation unit 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 the 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 generation unit 15 then generates a shape obtained by left-right inverting the third shape of the third information accepted by the input unit 2, as the first shape to be used by the first selection processing unit 12.

7 is a diagram illustrating the generation of an inverted shape as an example. 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 enter the third information, and the user enters the third information into the input unit 2. When the input of the third information is accepted, for example, as shown in FIG. 7, a virtual symmetry plane VS is placed on the third shape SH11, and for each point in the point cloud data of the third shape SH11, a corresponding point PG2 is found on the side opposite the virtual symmetry plane VS from where the third shape SH11 is placed, at the distance between 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, a symbol representing right (e.g., "R") or left (e.g., "L") may be added to the file name of the second shape, and the inverted shape may be automatically generated by referencing this.

In this way, 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. If the first bone is an affected bone, selecting the second selection information based on the first shape of this affected bone may result in a second shape that 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, this error can be reduced, and an implant that can be used as a reference when designing the implant for the first bone can be more appropriately selected.

Furthermore, if 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 generation unit 15 may left-right invert one of the multiple second shapes represented by each of the multiple pieces 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 multiple second shapes (third variant). For example, if the first bone is on the right side, the inverted shape generation unit 15 left-right inverts the left second shape so that it becomes the right second shape. This allows the first selected information to be selected efficiently.

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 accepts input of a portion of the first bone. The deformed shape generation unit 16 generates one or more deformed second shapes for the second shape by modifying the shape of the portion accepted by the input unit 2. This allows a deformed second shape to be generated by deforming 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 describes an example in which a deformed second shape is generated for the second shape of the second information belonging to the third candidate group, but is not limited to this.

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

For example, the menu bar may include a "Transform" button for instructing the generation of a deformed shape. The design support device 1000 may display the "Transform" button on the menu bar from the time the device starts operating. The design support device 1000 may display the "Transform" button on the menu bar after selecting the third candidate group. The menu bar may also not have a "Transform" button. In this case, the design support device 1000 may create a deformed shape according to specified conditions when selecting the third candidate group.

If the menu bar includes a "Transform" button, when the user presses 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 basis for transformation from the third number of second shapes represented by each of the third number of second selection information.

The user inputs the selection of the second shape that will be the source of the transformation into the design support device 1000 via the input unit 2. For example, the mouse cursor is positioned over the display position of the second shape that the user wishes to transform, and the mouse is operated to input. Note that the second shape that will be the source of the transformation may be set appropriately in advance, and its input may be omitted. For example, a second shape that belongs to a third candidate group that meets predetermined conditions may be used as the second shape that will be the source of the transformation.

When an input operation to select a second shape to be transformed is received, the design support device 1000 displays, via the transformed shape generation unit 16, a message prompting the user to input the part, transformation method, transformation amount per transformation (transformation amount per transformation (unit transformation amount)), and 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, height, height, etc.). The user inputs the part, transformation method, unit transformation amount, and number of shapes to be generated into 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 part, 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 set appropriately 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. The design support device 1000 then causes the deformed shape generation unit 16 to further display the generated deformed second shape on the selection result display screen, and stores fourth information (post-deformation second information) representing the generated deformed second shape in the storage unit 5.

The deformed shape generation unit 16 may further store in the storage unit 5, as a single group, the second information of the second shape before the change and one or more pieces of deformed second information relating to one or more deformed second shapes. 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. As a result, when referencing a second shape selected as part of the third candidate group, the corresponding modified second information can be confirmed by referencing the associated group ID. Furthermore, for example, the first to third modified second information may be stored in the first storage unit 51.

Furthermore, in the above-described embodiment, the design support device 1000 may include a cartilage-imparting shape generation unit 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 generation unit 17 may generate a plurality of cartilage-imparting shapes by adding cartilage corresponding to the cartilage of the first bone at varying thicknesses to the second shape of the second information in the third candidate group selected by the second selection processing unit 13, and may generate each piece of 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, 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 third candidate group. The following describes an example in which the fifth information is generated for the second shape of the second information belonging to the third candidate group, but is not limited to this.

The cartilage-imparting shape generation unit 17 outputs these generated cartilage-imparting shapes to the output unit 3, along with a 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. This makes it possible to generate a plurality of cartilage-imparting shapes with different cartilage thicknesses, and these generated cartilage-imparting shapes can be used as reference in designing the first bone implant, allowing for more appropriate selection of the reference implant.

Figure 9 is a diagram illustrating, as an example, the generation of a cartilage-added shape. Figure 9A shows the second shape of the second information belonging to the third candidate group before cartilage is added, Figure 9B shows the second shape obtained by adding cartilage of a first thickness to the second shape shown in Figure 9A, Figure 9C shows the second shape obtained by adding cartilage of a second thickness thicker than the first thickness to the second shape shown in Figure 9A, and Figure 9D shows the second shape obtained by adding cartilage of a third thickness thicker than the second thickness to the second shape shown in Figure 9A ((first thickness) < second thickness) < third thickness)). It is determined whether the first bone has cartilage. If the first bone has cartilage, for example, three first to third cartilage-imparted shapes SC1 to SC3 are generated by adding three first to third cartilages CA1 to CA3 of 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 piece of fifth information representing the generated first to third cartilage-imparted shapes SC1 to SC3 is generated. The second shape SH30 to which cartilage is imparted may be selected, for example, by the user, or may be selected randomly by the design support device 1000. Alternatively, for example, all of the second shapes of the second information belonging to the third candidate group may be second shapes to which cartilage is imparted.

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 was 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.

In addition, in the above-described embodiment, the design support device 1000 may also include an enlarged/reduced shape generation unit 18 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 1 (sixth variant). The enlarged/reduced shape generation unit 18 calculates the distribution of each of a plurality of shape-related parameters for a plurality of second shapes in the plurality of second information of the first candidate group. The enlarged/reduced shape generation unit 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 of the first candidate group within each range (enlargement/reduction range) based on the calculated distribution, and by using the second information of the generated new second shapes as elements of the first candidate group, the number of elements in the first candidate group is increased. In other words, the enlarged/reduced shape generation unit 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 enlarged/reduced shape generation unit 18 generates the new second shape for each increase in number corresponding to each width of each distribution obtained. This prevents the formation of new second shapes that deviate from the distribution, and allows the number of elements in the first candidate group to be increased appropriately.

Figure 10 is an example diagram illustrating the generation of scaled shapes by scaling a shape. Figure 10A shows the distribution of length, width, and height, and Figure 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 enlarging a second shape. The horizontal axis of Figure 10A represents the length, width, and height classes, and the vertical axis represents the frequency (number) of each.

For example, the menu bar includes a "Scale" button for instructing scaling. When the user operates the "Scale" button via the input unit 2, the scaled shape generation unit 18 calculates the distribution of each of the multiple parameters, namely, length, width, and height, for the multiple second shapes in the multiple pieces of second information stored in the first storage unit 51, as shown in FIG. 10A. 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 for the first candidate group, thereby increasing the number of elements in the first candidate group. When storing the information, as described above, 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 for the basic shape SH40.

Note that the example shown in FIG. 10 is merely an example and is not limited to this. The scaling range may be any range, such as from -σ to +σ, the number of items to be scaled may be any number, such as 5 or 10, and the reduction and enlargement rates may also be any number, such as 5% or 10%. The scaling range, the number of items to be scaled, and the reduction and enlargement rates are set appropriately in advance or by input specification by the user via the input unit 2. The number of items to be scaled 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 items to be scaled. The larger the coefficient of variation, the larger the number of items to be scaled.

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

While the scaling shape generation unit 18 scales the entire second shape in the above description, it may scale one or more portions of the second shape. More specifically, the scaling shape generation unit 18 calculates the 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 pieces of second information in the first candidate group, generates one or more new second shapes by scaling one second shape selected from the multiple second shapes in the multiple pieces of second information in the first candidate group within one or more scaling ranges based on the calculated length distribution of one or more portions, and uses the second information of the generated new second shape as an element of the first candidate group, thereby increasing the number of elements in the first candidate group. The portions are 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 specific portions. 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, making it possible to more appropriately select implants that can be used as a reference when designing the implant for the first bone.

The enlarged/reduced shape generation unit 18 may generate the new second shape for an increased number corresponding to the width of the one length distribution obtained, or for each of multiple increased numbers corresponding to the width of each of multiple length distributions. If there are multiple parts, the multiple increased numbers may be set based on the standard deviation or coefficient of variation of the multiple 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.

Furthermore, if the radius of curvature of the curved portion in the new second shape generated by the scaling is smaller than the minimum radius of curvature, the scaled shape generation unit 18 may replace the radius of curvature with the minimum radius of curvature to deform the new second shape, and use the deformed new second shape as an element of the first candidate group. In this way, if there are constraints on the radius of curvature in the manufacture of the implant, it is possible to design an implant that satisfies the constraints.

Figure 11 is a diagram illustrating the replacement of curvature radii as an example. Figure 11A shows the basic shape SH40, first and second reduced shapes SH41A, SH41B, and first and second expanded shapes SH42A, SH42B shown in Figure 10B, which illustrates the curvature radius R, before the replacement of curvature radii, while Figure 11B shows the shapes after the replacement of curvature radii. For example, if the minimum curvature radius is curvature radius R1.5, as shown in Figure 11A, the first reduced shape SH41A has a curvature radius R1.0, so as shown in Figure 11B, the first reduced shape SH41A is transformed into a first reduced shape SH41Aa in which the curvature radius R1.0 is replaced with a 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, replacing the second information representing the first reduced shape SHA.

Furthermore, in the above-described embodiment, the design support device 1000 may include a parameter generation unit 19 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 1 (seventh variant). The parameter generation unit 19 generates multiple shape-related parameters (third parameters) for the second shape of the implant based on multiple pieces of second information from the first candidate group, so that the number of new parameters (fourth parameters) is a predetermined number (fourth number) less 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 parameter using the parameter generation unit 19, the number of parameters can be reduced. The parameter generation unit 19 then sets multiple pieces of new data (new data points) represented by the fourth parameter so that they are evenly distributed within a predetermined range, finds each value, and converts each value of these multiple new data represented by the fourth parameter into each value represented by the third parameter.

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

More specifically, for example, the menu bar includes a "Generate Parameter" button for instructing the generation of new parameters. When the user presses the "Generate Parameter" button via the input unit 2, the parameter generation unit 19 first performs principal component analysis (PCA) using the multiple pieces of second information represented by third parameters stored in the first storage unit 51. Next, the parameter generation unit 19 extracts a fourth number of principal components from the multiple principal components obtained by PCA, starting with the first principal component with the highest contribution rate, as fourth parameters. The fourth number is set in advance as an appropriate integer value, for example, between 3 and 6. In one example, the fourth number is 3, and the first to third principal components are extracted as 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 parameter 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 generator 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. The parameter generation unit 19 then 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 generation unit 19 may be stored in the first storage unit 51 as a new first candidate group.

Principal component analysis may be performed using covariance without standardizing the third parameters. 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 changes significantly with respect to a change in the radius of the curved surface R.

Furthermore, in the above-described embodiment, the design support device 1000 may include a shape optimization unit 20 functionally configured in the control processing unit 1, as shown by the dashed line in FIG. 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) 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, to the first shape of the body part that the input unit 2 has received as first information.

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

The second shape to be optimized is, for example, input by a user (operator) via input unit 2. Alternatively, for example, the second shape to be optimized is selected from a third candidate group by a user's input operation via 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.

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 multiple 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 distance between the corresponding points for the determined multiple 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 that generates a new current second shape 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 process is performed for that one parameter; if there are multiple parameters to be optimized, the above process is performed for each parameter to be optimized, one by one.

It should be noted 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 made for combinations of values of the multiple parameters to be optimized until the second shape difference changes from decreasing to increasing.

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

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 variant). 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 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 of 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 base shape is not necessary.

Figure 15 is a diagram illustrating the display of the difference amount as an example. Figure 15A shows the talus (first shape), and Figure 15B shows the implant (second shape) of the talus model shown in Figure 15A.

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 determined, and this determined amount of shape difference is displayed on the output unit 3 of the display device.

More specifically, for example, the menu bar includes a "Difference Calculation Display" button for instructing the 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 select 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 each shape BP1, 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 for that point. The difference calculation and display unit 21 then displays each point in 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 that point. For example, the possible range of shape difference amount is divided into eight sections, and the shape difference amount is displayed on an eight-level grayscale. This allows the implant's finish to be visually confirmed, and improves the visibility of the trim position.

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 also be selected from the second information and first information stored in the memory unit 5, or may be selected from a third candidate group, and the first shape BP2 corresponding to the selected second shape BP1 may be searched for and selected from the memory unit 5.

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.

In order to express the present invention, the present invention has been appropriately and sufficiently described above through embodiments with reference to the drawings. However, it should be recognized that those skilled in the art could easily modify and/or improve the above-described embodiments. Therefore, unless modifications or improvements made by those skilled in the art are at a level that causes them to depart from the scope of the claims set forth in the claims, such modifications or improvements are construed as being encompassed within the scope of the claims.

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 (24)

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 related to a second shape of the implant, a plurality of pieces of second information that satisfy a first condition in relation to the first information as a second candidate group;
a second selection processing unit that selects, from at least a portion 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;
The second selection processing unit further associates order information regarding an order under the second condition with the second information.
Design support system. the first condition is that a volume difference between the first shape and a second shape of second information that is an element of the first candidate group is equal to or less than a predetermined first threshold value;
the first selection processing unit determines that the second shape satisfies the first condition when the volume difference is equal to or less than the first threshold, and selects second information of the determined second shape as an element of the second candidate group.
The design support system according to claim 1 . the first condition is that a dimensional product obtained by multiplying a vertical length difference, a horizontal length difference, and a height difference between the first shape and a second shape of second information that is an element of the first candidate group is equal to or less than a predetermined second threshold value;
the first selection processing unit determines that the second shape satisfies the first condition when the dimensional area is equal to or less than the second threshold, and selects second information of the determined second shape as an element of the second candidate group.
The design support system according to claim 1 . the second condition is that the shape difference between the first shape and the second shape is within a predetermined number in ascending order,
The order in the second condition is the order of the magnitude of the shape difference.
4. The design support system according to claim 1. the second selection processing unit determines a plurality of corresponding points between the first shape and the second shape, and determines, as the shape difference, a root mean square error of distances between the determined corresponding points.
The design support system according to claim 4. The second selection processing unit
determining, as the shape difference, a difference between a value of one parameter relating to the second shape and a value of the parameter in the first shape; or
calculating differences between the values of a plurality of shape-related parameters in the second shape and the values of the plurality of shape-related parameters in the first shape, and calculating a linear sum or a weighted linear sum of the differences as the shape difference;
The design support system according to claim 4. the second selection processing unit determines a plurality of corresponding points between the first shape and the second shape, and calculates a root mean square error of distances between the determined plurality of corresponding points;
A difference between a value of one shape-related parameter in the second shape and a value of the parameter in the first shape is calculated, and the shape difference is calculated as a linear sum or a weighted linear sum of the calculated mean square error and the calculated difference, or
calculating differences between the values of a plurality of shape-related parameters in the second shape and the values of the plurality of shape-related parameters in the first shape, and calculating, as the shape difference, a linear sum or a weighted linear sum of the calculated mean squared errors and the calculated differences;
The design support system according to claim 4. The value of each of the plurality of parameters varies independently of changes in the values of the other parameters.
8. The design support system according to claim 6 or 7. weights for the plurality of parameters in the weighted linear sum are set based on a distribution of parameter values;
The design support system according to claim 8. the first information is represented by first point cloud data representing the first shape,
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;
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 second point cloud data in the first region in the second shape and first point cloud data in a 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 second point cloud data in the first region in the second shape and first point cloud data in a second region corresponding to the first region in the first shape,
the second selection processing unit selects the third candidate group using second point cloud data of second information of the new second candidate group generated by the data number increasing/decreasing unit and first point cloud data of new first information;
10. The design support system according to claim 1. The implant is a pair of bone implants or a talus implant.
The design support system according to any one of claims 1 to 10. the body part is a first bone;
the first bone is either one of a pair of left and right bones or either one of a pair of left and right talus bones,
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;
The apparatus further includes an inverted shape generating unit that generates a shape obtained by horizontally inverting the third shape of the third information received by the input unit as a first shape to be used by the first selection processing unit.
The design support system according to any one of claims 1 to 11. the body part is a first bone;
the input unit further receives an input of a part of the first bone;
a deformed shape generating unit that generates one or more deformed second shapes by changing the shape of a portion of the second shape of the second information that is an element of the third candidate group and that is received by the input unit;
The design support system according to any one of claims 1 to 11. Further comprising a storage unit,
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 on one or more deformed second shapes as one group.
The design support system according to claim 13. the body part is a first bone;
If the first bone has cartilage, a cartilage-imparting shape generating unit generates a plurality of cartilage-imparting shapes by adding cartilage corresponding to the cartilage of the first bone with varying thicknesses to the second shape of the second information in the third candidate group selected by the second selection processing unit, and generates each of the plurality of cartilage-imparting shapes generated as an element of a new third candidate group.
The design support system according to any one of claims 1 to 11. Further comprising a storage unit,
The cartilage-imparting shape generation unit further stores the plurality of fifth information as one group in the storage unit in association with the second information before the cartilage is imparted.
The design support system according to claim 15. the device further comprises an enlarged/contracted shape generating unit that calculates a distribution of each of a plurality of shape-related parameters for a plurality of second shapes in the plurality of second information of the first candidate group, generates one or a plurality of new second shapes by enlarging or reducing one second shape selected from the plurality of second shapes in the plurality of second information of the first candidate group within each range based on the calculated distribution, and increases the number of elements in the first candidate group by using the second information of the generated new second shapes as elements of the first candidate group;
17. The design support system according to claim 1. the enlarged/reduced shape generation unit generates the new second shape for each increased number corresponding to each width of the distribution obtained.
The design support system according to claim 17. a scaled shape generating unit that generates one or more new second shapes by scaling one second shape selected from the plurality of second shapes in the plurality of second information of the first candidate group within one or more scaled ranges based on the calculated length distribution of one or more parts of the second shapes, and sets the second information of the generated new second shapes as an element of the first candidate group, thereby increasing the number of elements in the first candidate group;
17. The design support system according to claim 1. the enlarged/reduced shape generating unit generates the new second shape for an increased number corresponding to a width of the obtained one length distribution, or for each of a plurality of increased numbers corresponding to each width of a plurality of length distributions.
20. The design support system according to claim 19. When the number of the portions is multiple, the multiple increased numbers are set based on the standard deviation or the coefficient of variation in the multiple length distributions.
The design support system according to claim 20. the enlarged/reduced shape generation unit further deforms the new second shape by replacing a radius of curvature of a curved portion in the new second shape with the minimum radius of curvature when the radius of curvature of the curved portion in the new second shape is smaller than a minimum radius of curvature, and sets the deformed new second shape as an element of the first candidate group.
20. The design support system according to claim 17 or 19. an input step of receiving input of first information relating to a first shape of a body part;
a first selection process step of selecting, 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 information as a second candidate group;
a second selection process step of selecting, from at least a portion 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;
The second selection process further includes associating order information regarding an order under the second condition with the second information.
Design support method. A design support program that causes a computer to function as the design support system according to any one of claims 1 to 21.