Navigation system, jig, and program

Abstract

This navigation system comprises: an acquisition unit that acquires information about the position and attitude of a first sensor that are detected on the basis of a signal from the first sensor, which is inserted into a first jig attachment portion in a first orientation predetermined with respect to the first jig, the first jig having a surface with a shape corresponding to the surface of a first bone, and information about a target attachment position and a target attachment attitude of the first sensor with respect to the position and attitude of a second sensor that are detected on the basis of a signal from the second sensor, which is inserted into a second jig attachment portion in a second orientation predetermined with respect to the second jig, the second jig having a surface with a shape corresponding to the surface of a second bone; a derivation unit that derives a first relative position and a first relative attitude of the first sensor on the basis of the target attachment position, the target attachment attitude, and the position and attitude of the first sensor; an information generation unit that generates an image of a 3-dimensional coordinate axis representing the target attachment position and the target attachment attitude, and an image of a 3-dimensional coordinate axis representing the first relative position and the first relative attitude; and a display unit that displays the images of the 3-dimensional coordinate axes.

Description

Navigation system, fixture and program

[0001] The present invention relates to a navigation system, a jig, and a program.

[0002] Advances in image processing technology have made it common to perform preoperative planning (3D simulation) prior to surgery. For example, in orthognathic surgery, surgeons may separate the maxilla (Le Fort I fragment) from the skull. The surgeon then precisely moves the maxilla to a target relative position relative to the skull, and then reattaches the maxilla to the skull at the target relative position.

[0003] In preoperative planning for such orthognathic surgery, a patient's skull model and maxilla model are moved and rotated on the screen of the display unit of a planning device (information processing device), and the planner (doctor) considers the target relative position of the maxilla to the actual position of the skull, with the aim of achieving a good occlusion and an aesthetic facial appearance for the patient.

[0004] One method for reflecting the results of preoperative planning on target relative positions in actual surgery is navigation surgery. In optical navigation surgery, the position of a surgical instrument is detected in real time by distance measurement using infrared light reflected from a reflector attached to the surgical instrument.

[0005] Furthermore, the application of electromagnetic (EM) navigation surgery to sinus surgery, catheter treatment, etc. is being considered. In magnetic navigation surgery, the position of a surgical instrument (non-magnetic material) is detected in real time by a magnetic tracking system based on the output of a magnetic sensor attached to the surgical instrument (see Non-Patent Document 1).

[0006] Patent Literature 1 discloses a surgical system that performs optical or magnetic navigation in craniomaxillofacial surgery, and Patent Literature 2 discloses an optical maxillary alignment system that uses a mouthpiece-type target and a camera.

[0007] US Patent Application Publication No. 2017 / 0000505 US Patent Application Publication No. 2009 / 0220122

[0008] "Magnetic 3D Measurement System AURORA", [online], August 2, 2022, Advanced Systems Co., Ltd., [Retrieved August 2, 2022], Internet <URL: http: / / www.asco.jp / 02aurora.htm>

[0009] However, Patent Document 1 discloses a position detection reference module having a complex shape as a detection reference module used in a magnetic navigation system. A position detection reference module having such a complex shape is problematic in that it gets in the way during surgery. Furthermore, a position detection reference module having an exposed shape detects a position far from the actual bone position as the bone position. Therefore, even if the bone is accurately moved to the position guided by the navigation system, that position is not the accurate target position, and therefore, there is a problem in that the surgeon cannot accurately align the bone position with the accurate target position.

[0010] Furthermore, in Patent Document 1, the position detection reference module that detects the position of the moved bone fragment is attached to a cutting guide that separates the jawbone from the skull. When such a cutting guide is used, it is time-consuming to align the upper and lower jaws, and there are often no noticeable marks on the bones that can be used for alignment, making it difficult to visually install a sensor at the target attachment position determined in preoperative planning. For this reason, it is not preferable to attach the position detection reference module to a cutting guide.

[0011] In Patent Document 2, the maxilla is aligned using a mouthpiece-type dental splint (mouthpiece). In such alignment surgery, it is preferable to integrate the maxilla and mandible. However, the shape of the target having four light sources for alignment is exposed to the outside from the dental splint, similar to the position detection reference module in Patent Document 1, so that distance measurement using a camera is possible. Therefore, not only does the target interfere with the surgery, but the target's distance from the position of the teeth may prevent accurate alignment of the bones. Furthermore, because the target is exposed to the outside from the dental splint, the position of the target as the alignment origin may shift, making accurate alignment of the bones difficult.

[0012] Furthermore, in Patent Document 2, surgeons and caregivers may be crowded around the patient's head. In such cases, in optical navigation surgery using a reflector exposed on the outside of a dental splint as in Patent Document 2, optical blockage may occur due to the surgeon or other personnel. That is, infrared rays reflected by a reflector attached to a surgical instrument may be blocked by the surgeon or other personnel. When optical blockage occurs, infrared rays cannot be used for distance measurement, and the position of the surgical instrument cannot be detected. This situation is similar, for example, when a reflector is attached to the bone of a patient undergoing surgery.

[0013] In contrast, in the magnetic navigation surgery described in Non-Patent Document 1, the position of a surgical instrument or bone is detected based on the output of a small magnetic sensor attached to the surgical instrument or bone. Therefore, optical obstruction does not occur in magnetic navigation surgery. For these reasons, the application of magnetic navigation surgery using a small magnetic sensor to the field of oral surgery has been considered.

[0014] However, even if the magnetic navigation surgery described in Non-Patent Document 1 is applied to orthognathic surgery, depending on the attachment position of the magnetic sensor attached to the bone, there is no mark on the bone, and therefore the position of the maxilla and the position of the skull may be misaligned, as in Patent Document 1. As such, there is a problem in that it is difficult to assist the surgeon in accurately moving and rotating the bones so that they are in the target relative position and target relative posture predetermined by preoperative planning.

[0015] As described above, there are no marks on the bones of a patient undergoing orthognathic surgery to serve as guides for the positions where sensors such as reflectors and magnetic sensors should be attached with screws or the like. This poses a problem in that the surgeon cannot visually grasp the exact positions (target attachment positions) where the sensors should be attached to the patient's bones. Furthermore, with navigation that presents the surgeon with numerical values ​​for the target relative positions as in Patent Document 1, there is a problem in that the surgeon cannot intuitively grasp whether the bones have been accurately moved and rotated so that the relative positions and relative orientations of the bones become the target relative positions and relative orientations.

[0016] In view of the above circumstances, the present invention aims to provide a navigation system, a jig, and a program that can assist a surgeon in accurately moving and rotating bones so that the relative positions and relative orientations of the bones become target relative positions and target relative orientations.

[0017] One aspect of the present invention is an apparatus including: an acquisition unit that acquires information on the position and orientation of a first sensor detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation with respect to a first jig having a surface shaped in accordance with the surface of the first bone; and information on a target mounting position and a target mounting orientation of the first sensor relative to the position and orientation of the second sensor detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation with respect to a second jig having a surface shaped in accordance with the surface of a second bone; The navigation system includes: a derivation unit that derives a first relative position and a first relative orientation of the first sensor with respect to the target mounting position and the target mounting orientation based on the mounting orientation and the position and orientation of the first sensor; an information generation unit that generates an image of three-dimensional coordinate axes representing the target mounting position and the target mounting orientation, and an image of three-dimensional coordinate axes representing the first relative position and the first relative orientation; and a display unit that displays the image of the three-dimensional coordinate axes representing the target mounting position and the target mounting orientation, and the image of the three-dimensional coordinate axes representing the first relative position and the first relative orientation.

[0018] One aspect of the present invention is an apparatus for detecting a position and orientation of a first bone detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation with respect to a first jig having a surface shaped according to a surface of the first bone, and a second bone detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation with respect to a second jig having a surface shaped according to a surface of a second bone; and an apparatus for detecting a relative position and orientation of the second bone with respect to a position of the first bone based on the position and orientation information of the first bone and the position and orientation information of the second bone. and a derivation unit that derives a target relative position and a target relative orientation of the second bone with respect to the position and orientation of the first bone based on a predetermined amount of movement with respect to an initial value of the relative position and a predetermined amount of rotation with respect to the initial value of the relative orientation; an information generation unit that generates an image of a three-dimensional coordinate axis representing the target relative position and the target relative orientation and an image of the three-dimensional coordinate axis representing the relative position and the relative orientation; and a display unit that displays the image of the three-dimensional coordinate axis representing the target relative position and the target relative orientation and the image of the three-dimensional coordinate axis representing the relative position and the relative orientation.

[0019] One aspect of the present invention is a jig having an attachment portion into which a sensor is inserted in a predetermined orientation, and a surface shaped to correspond to the surface of the bone to be joined.

[0020] One aspect of the present invention is a method for acquiring, in a computer, information on the position and orientation of a first sensor detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation with respect to a first jig having a surface shaped in accordance with a surface of a first bone, and information on a target mounting position and a target mounting orientation of the first sensor relative to the position and orientation of the second sensor detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation with respect to a second jig having a surface shaped in accordance with a surface of a second bone; and a program for executing the steps of: deriving a first relative position and a first relative orientation of the first sensor with respect to the target mounting position and the target mounting orientation, based on the target mounting orientation and the position and orientation of the first sensor; generating an image of three-dimensional coordinate axes representing the target mounting position and the target mounting orientation, and an image of three-dimensional coordinate axes representing the first relative position and the first relative orientation; and displaying the image of three-dimensional coordinate axes representing the target mounting position and the target mounting orientation, and the image of three-dimensional coordinate axes representing the first relative position and the first relative orientation.

[0021] One aspect of the present invention is a method for detecting the position and orientation of a first bone detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation relative to a first jig having a surface shaped in accordance with a surface of the first bone, and detecting the position and orientation of a second bone detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation relative to a second jig having a surface shaped in accordance with a surface of the second bone, and calculating the position and orientation of the second bone relative to the position of the first bone based on the position and orientation information of the first bone and the position and orientation information of the second bone. The program executes the steps of: deriving the relative position and relative orientation of bones; and deriving a target relative position and target relative orientation of the second bone with respect to the position and orientation of the first bone based on a predetermined amount of movement with respect to an initial value of the relative position and a predetermined amount of rotation with respect to the initial value of the relative orientation; generating an image of three-dimensional coordinate axes representing the target relative position and the target relative orientation, and an image of three-dimensional coordinate axes representing the relative position and the relative orientation; and displaying the image of the three-dimensional coordinate axes representing the target relative position and the target relative orientation, and the image of the three-dimensional coordinate axes representing the relative position and the relative orientation.

[0022] The present invention can assist the surgeon in accurately moving and rotating bones so that the relative positions and orientations of the bones become target relative positions and target relative orientations.

[0023] 1 is a diagram showing an example of the configuration of a navigation system in the first embodiment. FIG. 1 is a diagram showing a skull model and a maxilla model in the first embodiment. FIG. 2 is a diagram showing an example of the position and posture of the maxilla model before and after movement in the first embodiment. FIG. 3 is a diagram showing an example of determining movement parameters and rotation parameters (rotation matrix) in the first embodiment. FIG. 4 is a diagram showing an example of specifying attachment positions of magnetic sensors in the first embodiment. FIG. 5 is a diagram showing an example of a jig to be joined to the skull in the first embodiment. FIG. 6 is a diagram showing an example of a jig to be joined to the maxillary dentition in the first embodiment. FIG. 7 is a diagram showing an example of a navigation image showing attachment positions in the first embodiment. FIG. 8 is a diagram showing an example of attachment of magnetic sensors in the first embodiment. FIG. 9 is a diagram showing an example of a navigation image showing bone positions and the like in the first embodiment. FIG. 10 is a diagram showing an example of a navigation image showing bone positions and the like in the first embodiment. FIG. 11 is a flowchart showing a first example of operation of the navigation device in the first embodiment. FIG. 12 is a flowchart showing a second example of operation of the navigation device in the first embodiment. FIG. 13 is a diagram showing a first example of specifying attachment positions of magnetic sensors in the second embodiment. FIG. 14 is a diagram showing an example of cutting a bone in the second embodiment. 10A and 10B are diagrams illustrating examples of attachment positions of magnetic sensors after cutting a bone in the second embodiment.

[0024] Embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) Fig. 1 is a diagram showing an example of the configuration of a navigation system 1 (surgery support system) in the first embodiment. The navigation system 1 is a system that navigates the relative position and relative orientation of a sensor with respect to a target attachment position and target attachment orientation predetermined on a patient's bone. This allows a surgeon (doctor) to accurately attach a sensor (jig) to a patient's bone so that the orientation of the sensor at the target attachment position predetermined on the patient's bone becomes the target attachment orientation. The target attachment position and target attachment orientation are predetermined by a planner (doctor) in preoperative planning (a three-dimensional simulation performed before surgery).

[0025] The sensor attached to the patient's bone may be a light source or reflector used in optical navigation surgery, or a magnetic sensor used in magnetic navigation surgery. Magnetic sensors are more preferable because they do not cause optical obstruction. In the following, as an example, a magnetic sensor is attached to the patient's bone by the surgeon.

[0026] The navigation system 1 is a system for navigating the relative positions and orientations of the patient's bones with respect to predetermined target relative positions and target relative orientations. This allows the surgeon to set the relative position and orientation of a second bone with respect to the position and orientation of a first bone to the predetermined target relative position and target relative orientation. The target relative position and target relative orientation are predetermined by the planner during preoperative planning.

[0027] The navigation system 1 includes a planning device 2, a storage device 3, a communication line 4, a detection device 5, and a navigation device 6. A jig 210 (first jig) and a magnetic sensor 301-1 (first sensor) are associated with a bone 101 (first bone) of a patient. Furthermore, a jig 220 (second jig) and a magnetic sensor 301-2 (second sensor) are associated with a bone 102 (first bone) of a patient.

[0028] In an embodiment of the present invention, the jig 220 is preferably a mouthpiece (dental splint). The magnetic sensor 301-2 is attached to the bone 102 using the jig 220. The joint surface of the jig 220 is manufactured to fit the shape of the dentition, allowing the surgeon to accurately install the magnetic sensor 301-2 at a target installation position determined on the bone. In an embodiment of the present invention, the position of the jig 220 that can accurately install the sensor at a target installation position determined on the bone is set as the origin, and a target relative position and target relative orientation are determined with respect to the origin, allowing the surgeon to accurately align the bone. Note that the jig 220 does not have to be a mouthpiece as long as the magnetic sensor 301-2 can be accurately installed at a target installation position determined on the bone.

[0029] The planning device 2 only needs to be included in the navigation system 1 during preoperative planning, but does not need to be included in the navigation system 1 during surgery.

[0030] The planning device 2 (preoperative planning device) includes a movement processing unit 21, a rotation processing unit 22, a display unit 23, and a conversion unit 24. The movement processing unit 21 and the rotation processing unit 22 may be integrated (a movement and rotation processing unit). The detection device 5 includes a magnetic field generation unit 51, an acquisition unit 52, a detection unit 53, and a communication unit 54. The navigation device 6 includes a communication unit 61, a storage unit 62, an acquisition unit 63, a derivation unit 64, an information generation unit 65, and a display unit 66.

[0031] Some or all of the functional units of the planning device 2 and the navigation device 6 are realized as software by a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit having a non-volatile recording medium (non-temporary recording medium). Also, some of the functional units of the detection device 5 are realized as software by a processor executing a program stored in a storage unit having a non-volatile recording medium (non-temporary recording medium).

[0032] The program may be recorded on a computer-readable recording medium, such as a portable medium such as a flexible disk, a magneto-optical disk, a read-only memory (ROM), or a compact disc read-only memory (CD-ROM), or a non-transitory recording medium such as a hard disk built into a computer system or a storage device such as a solid-state drive.

[0033] Some or all of the functional units of the planning device 2 and the navigation device 6 may be realized using hardware including an electronic circuit (electronic circuit or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). Also, some of the functional units of the detection device 5 may be realized using hardware including an electronic circuit (electronic circuit or circuitry) using, for example, an LSI, an ASIC, a PLD, or an FPGA.

[0034] Each of the bones 101 and 102 is a bone of a patient. In the following description, the bone 101 (first bone) is, for example, the patient's skull (facial bone), and the bone 102 (second bone) is, for example, a maxilla (Le Fort I bone fragment) separated from the bone 101.

[0035] <Determining the Target Relative Position and Target Relative Posture of the Bone 102 Before Surgery> Prior to surgery, a planner (not shown) performs preoperative planning using the planning device 2. For example, in preoperative planning performed prior to orthognathic surgery (Le Fort I osteotomy), a skull model (a three-dimensional model of the bone 101) is created in the memory of the planning device 2 based on data acquired by performing a CT (computed tomography) scan or the like on the patient.

[0036] Based on the skull model, an image of the skull model is displayed on the screen of the display unit 23. Furthermore, the maxilla model (a three-dimensional model of the bone 102) is separated from the skull model on the screen. As a result, images of the separated maxilla model and skull model are displayed on the screen of the display unit 23. In response to operations by the planner (e.g., mouse operations), the relative position (amount of movement) and relative orientation (amount of rotation) of the maxilla model with respect to the skull model are examined for the purpose of achieving a good occlusion and an aesthetic facial appearance for the patient.

[0037] Here, the movement processing unit 21 moves the maxilla model on the screen in accordance with an operation by the planner. The planner determines the movement amount (X-axis component amount, Y-axis component amount, Z-axis component amount) of the maxilla model relative to the initial value of its position by checking the movement amount of the maxilla model on the screen. This allows the planner to determine the movement amount of the actual bone 102 relative to the initial value of its position. The movement processing unit 21 records information on the movement amount determined by the planner in the storage device 3.

[0038] The rotation processing unit 22 may rotate the three-dimensional model of the maxilla model on the screen in response to an operation by the planner. The planner determines the amount of rotation of the maxilla model relative to the initial value of the position of the maxilla model by checking the amount of rotation (roll axis component amount, pitch axis component amount, yaw axis component amount) of the maxilla model on the screen. This allows the planner to determine the amount of rotation relative to the initial value of the position of the actual bone 102. The rotation processing unit 22 records information on the amount of rotation determined by the planner in the storage device 3.

[0039] <Determining the Mounting Position of the Sensor to be Attached to the Bone Using a Jig Before Surgery> In preoperative planning, the planner specifies the target mounting position of the magnetic sensor 301-1 (jig 210) on the bone 101 to the conversion unit 24. When the bone 101 is the skull, the target mounting position is, for example, a position determined on the lateral edge of the pyriform orifice of the skull.

[0040] The planner specifies the target attachment position of the magnetic sensor 301-1 on the screen of the display unit 23 while the maxilla model is not detached from the skull model on the screen of the display unit 23. The planner may also specify the target attachment position of the magnetic sensor 301-1 on the screen while the maxilla model is detached from the skull model on the screen of the display unit 23.

[0041] The planner joins a model of the jig 220 (mouthpiece) to the row of teeth of the maxilla model that has been moved and rotated to a target relative position and target relative posture with respect to the skull model on the screen of the display unit 23. The planner specifies the target attachment position of the magnetic sensor 301-1 (jig 210) on the skull model on the screen, for example, by operating a mouse. This allows the planner to input the target attachment position of the magnetic sensor 301-1 on the actual bone 101 to the conversion unit 24. In an embodiment of the present invention, the target attachment position of the magnetic sensor 301-1 is expressed with a predetermined position of the jig 220 joined to the row of teeth of the maxilla model as the origin.

[0042] The conversion unit 24 converts a first position (first two-dimensional position information) designated on the surface of the skull model by the planner using the screen (two-dimensional) of the display unit 23 into three-dimensional position information. This three-dimensional position information corresponds to the target attachment position of the magnetic sensor 301-1 (jig 210) on the actual bone 101. The conversion unit 24 records the three-dimensional position information of the target attachment position of the magnetic sensor 301-1 in the storage device 3.

[0043] The conversion unit 24 may also convert a second position (second two-dimensional position information) designated on the surface of the maxillary bone model by the planner using the screen (two-dimensional) of the display unit 23 into three-dimensional position information. This three-dimensional position information corresponds to the target attachment position of the magnetic sensor 301-2 (jig 220) on the actual bone 102. The conversion unit 24 records the three-dimensional position information of the target attachment position of the magnetic sensor 301-2 in the storage device 3.

[0044] The jigs 210 and 220 are manufactured before surgery using, for example, a three-dimensional printer (3D printer). Note that the conversion unit 24 may determine the orientation of the cylindrical attachment portion of the jig 210 (target attachment posture) according to the orientation of the jig 210 attached to the target attachment position on the skull model.

[0045] The storage device 3 pre-stores shape information of the 3D model of the skull model and shape information of the 3D model of the maxilla model. The data format of the 3D models of the skull model and maxilla model is, for example, DICOM (Digital Imaging and Communications in Medicine). Here, the data format of the 3D model of the dentition is, for example, STL (Stereolithography). The storage device 3 stores information on the amount of movement (movement parameters) and information on the amount of rotation (rotation parameters) in accordance with a control signal transmitted from the planning device 2.

[0046] <Outline of navigation of sensor attachment position during surgery> The detection device 5 generates a magnetic field region in a predetermined range of real space that includes the patient's head and each magnetic sensor 301. The detection device 5 detects (tracks) the position and orientation of each magnetic sensor 301 in real time based on the output (signal) of each magnetic sensor 301 in the generated magnetic field region.

[0047] The operator attaches the magnetic sensor 301-1 to the attachment portion of the jig 210. The operator also attaches the magnetic sensor 301-2 to the attachment portion of the jig 220.

[0048] The navigation device 6 presents (guides) to the surgeon in real time predetermined first information for navigating the position and posture of the magnetic sensor 301-1, so that the surgeon moves and rotates the jig 210 and the magnetic sensor 301-1, using the position of the magnetic sensor 301-2 inserted into the jig 220 as the origin, until the position and posture of the magnetic sensor 301-1 match the target mounting position and target mounting posture of the magnetic sensor 301 that are predetermined on the patient's bone 101.

[0049] Jigs are often attached to the lateral edge of the piriform mouth and the mandible, but there are no conspicuous marks on the lateral edge of the piriform mouth and the mandible. For this reason, it has been difficult to visually install each jig on the lateral edge of the piriform mouth and the mandible according to preoperative planning. In an embodiment of the present invention, the position of the attachment portion 221 provided on the jig 220, which can accurately attach the magnetic sensor 301-2 to a predetermined position (origin) on the mandible, is set as the origin. This makes it possible to present (guide) the surgeon to the exact attachment position of the jig 210 on the lateral edge of the piriform mouth.

[0050] The predetermined first information includes, for example, at least one of an image of a three-dimensional model (skull model) of the bone 101 whose shape has been measured in advance, an image of a three-dimensional model (maxilla model) of the bone 102 whose shape has been measured in advance, an image of three-dimensional coordinate axes representing the relative positions and relative orientations of the magnetic sensors 301 (each jig), and an image of three-dimensional coordinate axes representing the target mounting positions and target mounting orientations. Details of the first information will be described later using Figures 8 and 9.

[0051] By presenting such first information to the surgeon in real time, the navigation system 1 assists the surgeon in accurately attaching the jig 210 (magnetic sensor 301-1) so that the relative posture of the magnetic sensor 301-1 becomes the target attachment posture at a predetermined target attachment position on the bone 101.

[0052] <Details of navigation of sensor attachment position during surgery> The jig 210 is a jig for fixing the magnetic sensor 301-1 to the bone 101. The jig 210 is temporarily fixed to the bone 101 by the surgeon. The jig 220 is a jig for fixing the magnetic sensor 301-2 to the bone 102. The jig 220 is temporarily fixed to the dentition of the bone 102 by the surgeon.

[0053] The magnetic sensor 301-1 is placed near the bone 101 using the jig 210. Near the bone means, for example, within a range of about 0.1 mm to about 10 mm from the bone. In the embodiment of the present invention, the magnetic sensor 301-1 is inserted into a hole in the mounting portion 211 provided in the jig 210. Since the magnetic sensor 301-1 is placed near the bone 101, accurate alignment of the bone 101 is possible.

[0054] The magnetic sensor 301 is a sensor that detects magnetism. The magnetic sensor 301 detects magnetism at its own position within the magnetic field generated by the magnetic field generating unit 51 at a predetermined cycle (e.g., 40 Hz) using a magnetic detection device such as a coil. The magnetic sensor 301 outputs an electric signal corresponding to the detected magnetism to the acquiring unit 52.

[0055] The magnetic sensor 301-1 is temporarily attached to a predetermined target attachment position on the surface of the bone 101 (skull) using the jig 210. That is, the magnetic sensor 301-1 is temporarily attached to the predetermined target attachment position on the surface of the bone 101 by being inserted into an attachment portion of the jig 210 that is temporarily fixed to the bone 101. Therefore, the position and orientation detected based on the output (signal) of the magnetic sensor 301-1 attached to the bone 101 represent the position and orientation of the bone 101.

[0056] The magnetic sensor 301-2 is temporarily attached to a predetermined target attachment position on the surface of the bone 102 using a jig 220 joined to the dentition of the bone 102. Similar to the insertion of the magnetic sensor 301-1 into the hole of the attachment portion 211 provided in the jig 210, the magnetic sensor 301-2 is inserted into the hole of the attachment portion 221 provided in the jig 220, whereby the magnetic sensor 301-2 is attached near the bone 102 using the jig 220. That is, the magnetic sensor 301-2 is temporarily attached to a predetermined target attachment position on the surface of the bone 102 by being inserted into the attachment portion of the jig 220 temporarily fixed to the dentition of the bone 102. Therefore, the position and orientation detected based on the output of the magnetic sensor 301-2 attached to the bone 102 represent the position and orientation of the bone 102.

[0057] The magnetic field generation unit 51 generates a magnetic field region in a predetermined range of real space including the bones 101, 102, and each magnetic sensor 301 (e.g., a range of real space including the patient's head). The acquisition unit 52 acquires the output (electrical signal corresponding to magnetism) of the magnetic sensor 301. The detection unit 53 detects the position and orientation of the magnetic sensor 301 at a predetermined cycle (e.g., 40 Hz) based on the output of the magnetic sensor 301. The detected position has three degrees of freedom (X-axis, Y-axis, and Z-axis). The detected orientation (tilt) has three degrees of freedom (roll axis, pitch axis, and yaw axis). The communication unit 54 transmits information on the position and orientation of the magnetic sensor 301 (six degrees of freedom in total) to the communication unit 61 at a predetermined cycle (e.g., 40 Hz).

[0058] The communication unit 61 acquires information on the shape of the three-dimensional model of the bone 101 and information on the shape of the three-dimensional model of the bone 102 from the storage device 3. The communication unit 61 acquires information on the target mounting position of the magnetic sensor 301-1 (jig 210) from the storage device 3. The communication unit 61 may acquire information on the target mounting orientation of the magnetic sensor 301-1 (jig 210) from the storage device 3. The communication unit 61 acquires information on the position and orientation of each magnetic sensor 301 from the communication unit 54 at a predetermined period.

[0059] The storage unit 62 stores information on the target mounting position of the magnetic sensor 301-1 (jig 210). The storage unit 62 stores information on the target mounting orientation of the magnetic sensor 301-1 (jig 210). The storage unit 62 (buffer memory) temporarily stores time-series information on the position and orientation of each magnetic sensor 301. The storage unit 62 temporarily stores time-series information on the position and orientation of the bone 101 and time-series information on the position and orientation of the bone 102. The storage unit 62 may store in advance computer programs executed by the derivation unit 64 and the information generation unit 65.

[0060] The acquisition unit 63 acquires information on the shape of the bone 101 and information on the shape of the bone 102 from the storage device 3. The acquisition unit 63 acquires information on the target mounting position and target mounting orientation of the magnetic sensor 301-1 from the communication unit 61 or the storage unit 62. Information on the position and orientation of the magnetic sensor 301-1 (jig 210) and information on the position and orientation of the magnetic sensor 301-2 (jig 220) are acquired from the communication unit 61 or the storage unit 62 at a predetermined period.

[0061] The derivation unit 64 derives in real time a target attachment position and a target attachment orientation that are predetermined on the surface of the bone 101 (skull) based on information on the target attachment position and the target attachment orientation specified by the planner, with the position of the magnetic sensor 301-2 attached to the jig 220 joined to the dentition as the origin. The derivation unit 64 derives in real time the relative position and the relative orientation of the magnetic sensor 301-1 (jig 210) with respect to the target attachment position and the target attachment orientation based on the acquired information on the position and the orientation of the magnetic sensor 301-1.

[0062] The information generator 65 generates a navigation image at a predetermined frame rate (e.g., 40 fps) using a predetermined image processing engine (a three-dimensional computer graphics drawing engine). The navigation image includes, for example, an image representing the appearance (shape) of the bone generated in the preoperative planning, predetermined text information, and an image of a three-dimensional coordinate axis.

[0063] The information generation unit 65 generates an image (image of the skull model) representing the appearance of the bone 101 according to the position and posture of the bone 101, and an image (image of the maxilla model) representing the appearance of the bone 102 according to the relative position and posture of the bone 102.

[0064] When each magnetic sensor 301 (each jig) is attached to each bone during surgery, the information generating unit 65 generates an image of three-dimensional coordinate axes representing the current position and posture of each magnetic sensor 301 (each jig). The information generating unit 65 also generates an image of three-dimensional coordinate axes representing the target attachment position and target attachment posture of the magnetic sensor 301-1.

[0065] The display unit 66 displays, at a predetermined frame rate (for example, 40 fps), the navigation image generated by the information generation unit 65. For example, the display unit 66 displays an image of three-dimensional coordinate axes representing the current position and orientation of the magnetic sensor 301-1 (jig 210) and an image of three-dimensional coordinate axes representing the target mounting position and target mounting orientation of the magnetic sensor 301-1 (jig 210).

[0066] The surgeon joins the jig 220 with the magnetic sensor 301-2 inserted therein to the dentition of the patient's bone 102. The surgeon also accurately attaches the jig 210 with the magnetic sensor 301-1 inserted therein to a predetermined target attachment position on the patient's bone 101 using a screw (metal screw) or the like while checking the navigation image. Here, the surgeon accurately attaches the magnetic sensor 301-1 to the bone 101 while checking the navigation image so that the relative orientation of the magnetic sensor 301-1 with respect to the orientation of the magnetic sensor 301-2 becomes the target attachment orientation.

[0067] <Outline of Navigation of Relative Movement and Relative Rotation of Bones During Surgery> The surgeon separates the bone 102 (maxilla) from the bone 101 (skull). Here, the surgeon may temporarily remove the jig from the bone and then separate the bone 102 (maxilla) from the bone 101 (skull).

[0068] The detection device 5 generates a magnetic field region in a predetermined range of real space that includes the patient's head and each magnetic sensor 301. The detection device 5 detects (tracks) the position and orientation of each magnetic sensor 301 in real time based on the output (signal) of each magnetic sensor 301 in the generated magnetic field region.

[0069] The navigation device 6 presents (guides) to the surgeon in real time predetermined second information for navigating the movement and rotation of the bone 102 so that the surgeon can move and rotate the bone 102 until the relative position and relative orientation of the bone 102 to the position and orientation of the bone 101 coincide with the target relative position and target relative orientation.

[0070] The predetermined second information includes, for example, at least one of an image of a three-dimensional model (skull model) of the bone 101 whose shape has been measured in advance, an image of a three-dimensional model (maxilla model) of the bone 102 whose shape has been measured in advance, an image of three-dimensional coordinate axes representing the position and orientation of the bone 101, an image of three-dimensional coordinate axes representing the relative position and orientation of the bone 102 with respect to the position and orientation of the bone 101, and an image of three-dimensional coordinate axes representing the target relative position and target relative orientation of the bone 102. Details of the second information will be described later using FIGS.

[0071] By presenting such second information to the surgeon in real time, the navigation system 1 assists the surgeon in accurately moving and rotating (tilting) the bone 102 so that the position and posture of the bone 102 become the target relative position and target relative posture.

[0072] <Details of navigation of bone movement and rotation during surgery> The communication unit 61 acquires shape information of a three-dimensional model (skull model) of the bone 101 and shape information of a three-dimensional model (maxilla model) of the bone 102 from the storage device 3. The communication unit 61 acquires information on a predetermined amount of movement and information on a predetermined amount of rotation from the storage device 3. The communication unit 61 acquires information on the position and posture of the bone 101 and information on the position and posture of the bone 102 from the communication unit 54 at a predetermined period.

[0073] The storage unit 62 stores information on a predetermined amount of movement and information on a predetermined amount of rotation. The storage unit 62 (buffer memory) temporarily stores time-series information on the position and posture of the bone 101 and time-series information on the position and posture of the bone 102. The storage unit 62 may store in advance computer programs executed by the derivation unit 64 and the information generation unit 65.

[0074] The acquisition unit 63 acquires information on the shape of a three-dimensional model (skull model) of the bone 101 and information on the shape of a three-dimensional model (maxilla model) of the bone 102 from the storage device 3. The acquisition unit 63 acquires information on a predetermined amount of movement and information on a predetermined amount of rotation from the communication unit 61 or the storage unit 62. The acquisition unit 63 acquires information on the position and orientation of the magnetic sensor 301-1 (jig 210) and information on the position and orientation of the magnetic sensor 301-2 (jig 220) from the communication unit 61 or the storage unit 62 at a predetermined period.

[0075] When the magnetic sensor 301-1 (jig 210) is attached to the bone 101, the acquisition unit 63 acquires position and orientation information of the magnetic sensor 301-1 at a predetermined cycle from the communication unit 61 or the storage unit 62 as position and orientation information of the bone 101. Similarly, when the magnetic sensor 301-2 (jig 220) is attached to the bone 102, the acquisition unit 63 acquires position and orientation information of the magnetic sensor 301-2 at a predetermined cycle from the communication unit 61 or the storage unit 62 as position and orientation information of the bone 102.

[0076] The derivation unit 64 derives in real time the relative position and orientation of the magnetic sensor 301-2 with respect to the position and orientation of the magnetic sensor 301-1, based on the position and orientation information of the magnetic sensor 301-1 and the position and orientation information of the magnetic sensor 301-2. That is, the derivation unit 64 derives in real time the relative position and orientation of the bone 102 with respect to the position and orientation of the bone 101, based on the position and orientation information of the bone 101 and the position and orientation information of the bone 102.

[0077] The derivation unit 64 derives in real time a target relative position and orientation of the bone 102 with respect to the position and orientation of the bone 101, based on the relative position and orientation of the bone 102 and predetermined amounts of movement and rotation for the initial values ​​of the relative position and orientation of the bone 102 in preoperative planning. Here, the position and orientation obtained by moving and rotating the relative position and orientation of the bone 102 by the predetermined amounts of movement and rotation are the target relative position and orientation of the bone 102.

[0078] The information generator 65 generates a navigation image at a predetermined frame rate using a predetermined image processing engine. The navigation image includes, for example, an image representing the appearance (shape) of the bone generated in the preoperative planning, predetermined text information, and an image of a three-dimensional coordinate axis.

[0079] The information generation unit 65 generates an image (image of a skull model) representing the appearance of the bone 101 according to the position and posture of the bone 101, and an image (image of a maxilla model) representing the appearance of the bone 102 according to the relative position and posture of the bone 102. For example, when the bone 101 to which the magnetic sensor 301-1 is attached is turned sideways, the information generation unit 65 generates an image (image of a sideways skull model) representing the appearance of the bone 101 in the sideways position. For example, when the bone 102 to which the magnetic sensor 301-2 is attached moves, the information generation unit 65 moves the image representing the appearance of the bone 102 on the screen in accordance with the movement of the bone 102.

[0080] The information generating unit 65 generates, for example, an image of three-dimensional coordinate axes representing the target relative position and target relative orientation of the bone 102 based on the target relative position and target relative orientation of the bone 102 with respect to the position and orientation of the bone 101. For example, when the bone 101 to which the magnetic sensor 301-1 is attached is oriented sideways, the target relative position and target relative orientation of the bone 102 are also oriented sideways, so the information generating unit 65 generates a horizontally oriented image of the three-dimensional coordinate axes representing the target relative position and target relative orientation of the bone 102.

[0081] The information generating unit 65 generates, for example, an image of three-dimensional coordinate axes representing the relative position and relative orientation of the bone 102 based on the relative position and relative orientation of the bone 102 with respect to the position and orientation of the bone 101. The information generating unit 65 may also generate an image of a line connecting the relative position of the bone 102 and a target relative position. For example, when the bone 102 to which the magnetic sensor 301-2 is attached moves, the information generating unit 65 moves the image of the three-dimensional coordinate axes representing the relative position and relative orientation of the bone 102 on the screen in accordance with the movement of the bone 102.

[0082] The display unit 66 displays the navigation image generated by the information generating unit 65 at a predetermined frame rate (for example, 40 fps).

[0083] Next, preoperative planning before surgery will be described in more detail. Fig. 2 is a diagram showing a skull model 111 and a maxilla model 112 in the first embodiment. The skull model 111 corresponds to the bone 101 in real space. The maxilla model 112 corresponds to the bone 102 in real space.

[0084] Shape information (DICOM data) of the skull model 111 and the maxilla model 112 is obtained, for example, as a result of a CT scan performed on the patient's head before surgery. Note that data (STL data) obtained as a result of an optical digital scan performed on the patient's dentition before surgery may also be used as dentition data for the maxilla model 112.

[0085] FIG. 3 is a diagram showing an example of the position and orientation of the maxilla model 112 before and after movement in the first embodiment. In preoperative planning, the movement processing unit 21 moves the maxilla model 112 on the screen from the initial position value of the maxilla model 112 in response to mouse operations or the like by the planner (doctor). The rotation processing unit 22 rotates the maxilla model 112 on the screen from the initial orientation value of the maxilla model 112 in response to mouse operations or the like by the planner. The diagram on the left side shown in FIG. 3 shows the position (initial values) and orientation (initial values) of the skull model 111 before movement and rotation. The diagram on the right side shown in FIG. 3 shows the position and orientation of the skull model 111 after movement and rotation.

[0086] FIG. 4 is a diagram showing an example of determining movement parameters and rotation parameters (rotation matrix) in the first embodiment. In preoperative planning, the planner determines the relative position and relative orientation of the bone 102 after surgery by moving and rotating the maxilla model 112 on the screen from the initial values ​​of the position and orientation of the maxilla model 112. At least one of the movement processing unit 21 and the rotation processing unit 22 determines at least one of the movement amount and the rotation amount using a predetermined alignment algorithm. The predetermined alignment algorithm is, for example, an ICP (Iterative Closest Point) algorithm. The movement processing unit 21 records information on the determined movement amount (movement parameters) in the storage device 3. The rotation processing unit 22 records information on the determined rotation amount (rotation parameters) in the storage device 3.

[0087] Next, the designation of the attachment position of the magnetic sensor (jig) before surgery will be described. Fig. 5 is a diagram showing an example of designation of the attachment position (target attachment position) of the magnetic sensor 301 in the first embodiment. The left side of Fig. 5 shows the attachment position of the magnetic sensor 301 in a state before the maxilla model 112 is detached from the skull model 111 on the screen. In contrast, the right side of Fig. 5 shows the attachment position of the magnetic sensor 301 in a state after the maxilla model 112 has been detached from the skull model 111 and reattached to the skull model 111 on the screen.

[0088] 5, the jig 220 illustrated in FIG. 1 is sandwiched between the dentition of the maxilla model 112 and the dentition of the mandible model 113 and is bonded to both of them. Mounting position 10 represents the mounting position of the magnetic sensor 301-2 (jig 220) attached to the actual bone 102. Mounting position 11 represents the target mounting position of the magnetic sensor 301-1 attached to the actual bone 101. Mounting position 11 is expressed with mounting position 10 as the origin.

[0089] In preoperative planning, the planner specifies attachment position 10 as the attachment position (origin) of magnetic sensor 301-2 to bone 102 by, for example, using a mouse to make a mark on the surface of the dentition of maxilla model 112. The attachment position (origin) of magnetic sensor 301-2 is the position of the attachment portion of magnetic sensor 301-2 on jig 220. The planner also determines attachment position 11 as the attachment position (target attachment position) of magnetic sensor 301-1 to bone 101 by, for example, making a mark on the surface of skull model 111 (the piriform edge of the skull).

[0090] As shown on the left side of FIG. 5, the planner specifies, for example, attachment positions 10 and 11 on the screen in a state where the maxilla model 112 is not separated from the skull model 111.

[0091] As shown on the right side of Figure 5, the planner may specify the attachment position 10 and the attachment position 11 on the screen, for example, in a state in which the maxilla model 112 has been detached from the skull model 111 and reattached to the skull model 111. Here, the conversion unit 24 may correct the attachment position 11 in a state in which the maxilla model 112 has been reattached to the skull model 111 (the right side of Figure 5), to the attachment position 11 in a state in which the maxilla model 112 has not been detached from the skull model 111 (the left side of Figure 5). This allows the surgeon to accurately attach the magnetic sensor 301-1 (jig 210) to the attachment position 11 before detaching the bone 102 from the bone 101, even if the attachment position 11 is specified in preoperative planning in a state in which the maxilla model 112 has been reattached to the skull model 111.

[0092] Next, pre-operative jig production (jig modeling) will be described. FIG. 6 is a diagram showing an example of a jig to be joined to the skull (bone 101) in the first embodiment. The jig 210 is created using a CAD / CAM (computer-aided design / computer-aided manufacturing) technique. That is, design data for the shape of the jig 210 is designed based on DICOM data of the skull model 111. The jig 210 is manufactured, for example, by a three-dimensional printer (3D printer) based on the design data for the shape of the jig 210 (e.g., STL data).

[0093] The jig 210 is made of a non-magnetic material, such as resin, and has one or more attachment portions 211 for attaching the magnetic sensor 301-1, and a joining surface shaped according to the surface shape of the bone 101 (the pyriform edge of the skull) to be joined.

[0094] The shape of the attachment portion 211 is, for example, cylindrical. The tip of the magnetic sensor 301-1 (magnetic detection device) can be inserted into the attachment portion 211. By inserting the magnetic sensor 301-1 into the attachment portion 211, the magnetic sensor 301-1 is placed near the bone 101, and the position of the magnetic sensor 301-1 accurately represents the position of the bone 101. This makes it possible to align the relative position of the bone 102 with a target relative position with high accuracy.

[0095] The orientation of each attachment portion is designed based on the target attachment posture of jig 210 so that when jig 210 with magnetic sensor 301-1 inserted therein is attached to bone 101, the orientation of magnetic sensor 301-1 inserted in attachment portion 211 (a first orientation predetermined with respect to jig 210) and the orientation of magnetic sensor 301-2 inserted in attachment portion 221 of jig 220 (a second orientation predetermined with respect to jig 220) will be the same. In addition, the shape of the joint surface of jig 210 is designed to match the surface shape of bone 101 at the target attachment position of jig 210.

[0096] FIG. 7 is a diagram showing an example of a jig 220 (mouthpiece) (dental splint) to be attached to the dentition of the maxilla (bone 102) in the first embodiment. In orthognathic surgery, the patient's dentition is corrected before surgery to optimize the patient's dentition after surgery. To accurately attach the jig 220 to the corrected dentition, the jig 220 is a CAD / CAM splint (computer-aided design / computer-aided manufacturing splint) formed to have a bonding surface shaped according to the surface shape of the dentition. That is, design data for the shape of the jig 220 is designed based on the STL data of the maxilla model 112. Furthermore, the jig 220 is manufactured, for example, using a three-dimensional printer based on the design data for the shape of the jig 220. Since the jig 220 is attached to the patient's dentition, it is accurately fixed to the patient's maxilla (bone 102).

[0097] The jig 220 is made of a non-magnetic material, such as resin. The jig 220 has one or more attachment portions 221 for attaching the magnetic sensor 301-2, and a joint surface 222 shaped according to the surface shape of the bone 102 (the tooth row in the maxilla). The attachment portions 221 are shaped, for example, cylindrical. The tip portion (magnetic detection device) of the magnetic sensor 301-2 can be inserted into the attachment portion 221. By inserting the magnetic sensor 301-2 into the attachment portion 221, the magnetic sensor 301-2 is placed near the bone 102, and the position of the magnetic sensor 301-2 accurately represents the position of the bone 102.

[0098] Of the attachment portions 221-1, 221-2, and 221-3, the position of the attachment portion 221-1 is, for example, a position that passes through or near the midline of the patient when the joining surface 222 joins with the dentition of the bone 102. The magnetic sensor 301-2 may be attached to any of the attachment portions 221-1, 221-2, and 221-3.

[0099] The mouthpiece-shaped jig 220 is joined to the bone 102 and the mandible (not shown), thereby integrating the bone 102 and the mandible (not shown). In other words, the position of the patient's mandible follows the position of the bone 102 (maxilla) moved by the surgeon. Because the maxilla and mandible do not shift during movement, navigation can be performed more easily.

[0100] Next, navigation of the attachment position of the magnetic sensor 301 (jig) during surgery will be described in more detail. Fig. 8 is a diagram showing an example of a navigation image indicating the attachment position in the first embodiment. During surgery, the display unit 66 displays, in real time at a predetermined frame rate, a navigation image indicating the relative position and relative orientation of the magnetic sensor 301-1 with respect to the target attachment position and target attachment orientation of the magnetic sensor 301-1 (jig 210). Fig. 8 shows an example of a navigation image at a first time point during surgery.

[0101] The navigation image illustrated in FIG. 8 includes an image of a skull model 111, an image of a maxilla model 112, a jig image 213, a jig image 223, a coordinate axis image 14 positioned at the mounting position 10, a coordinate axis image 15 positioned at the mounting position 11, a coordinate axis image 16, a line image 17, and a display area 18.

[0102] Jig image 213 is an image of a three-dimensional model of jig 210. Jig image 223 is an image of a three-dimensional model of jig 220. Mounting position 10 is the mounting position (origin) of magnetic sensor 301-2. Mounting position 11 is the target mounting position of magnetic sensor 301-1 (jig 210).

[0103] The coordinate axis image 14 is represented by three mutually orthogonal line segments (X-axis, Y-axis, and Z-axis). The origin of the coordinate axis image 14 represents the position (mounting position 10) of the magnetic sensor 301-2 attached to the jig 220. The orientation of the coordinate axis image 14 represents the orientation of the magnetic sensor 301-2 attached to the mounting portion 221 of the jig 220.

[0104] The coordinate axis image 15 is represented by three mutually orthogonal line segments (X-axis, Y-axis, and Z-axis). The origin of the coordinate axis image 15 represents the target mounting position (mounting position 11) of the magnetic sensor 301-1. The orientation of the coordinate axis image 15 represents the target mounting orientation of the magnetic sensor 301-1.

[0105] The coordinate axis image 16 is represented by three mutually orthogonal line segments (X-axis, Y-axis, and Z-axis). The origin of the coordinate axis image 16 represents the relative position of the magnetic sensor 301-1 attached to the jig 210 with respect to the attachment position 11 (target attachment position). The orientation of the coordinate axis image 16 represents the orientation of the magnetic sensor 301-1 attached to the attachment portion 211 of the jig 210.

[0106] The line image 17 is a line connecting the target attachment position and the relative position of the magnetic sensor 301-1. The length of the line image 17 represents the difference (distance) between the target attachment position and the relative position of the magnetic sensor 301-1.

[0107] The color of the X-axis of the coordinate axis image 14, the color of the X-axis of the coordinate axis image 15, and the color of the X-axis of the coordinate axis image 16 are the same (e.g., red). The color of the Y-axis of the coordinate axis image 14, the color of the Y-axis of the coordinate axis image 15, and the color of the Y-axis of the coordinate axis image 16 are the same (e.g., blue). The color of the Z-axis of the coordinate axis image 14, the color of the Z-axis of the coordinate axis image 15, and the color of the Z-axis of the coordinate axis image 16 are the same (e.g., green). In addition, the color of the line image 17 connecting the origin of the coordinate axis image 15 (target mounting position) and the origin of the coordinate axis image 16 (the relative position of the magnetic sensor 301-1 at the current time) is purple, for example.

[0108] The display area 18 is an area where at least one of numerical information and text information is displayed. The numerical information displayed in the display area 18 indicates the difference between the target attachment position and the relative position of the magnetic sensor 301-1. The text information displayed in the display area 18 indicates the movement direction that reduces the difference between the target attachment position and the relative position of the magnetic sensor 301-1.

[0109] The surgeon attaches magnetic sensor 301-1 to mounting portion 211 of jig 210. The surgeon also attaches magnetic sensor 301-2 to mounting portion 221-1 of jig 220. The surgeon joins jig 220 to bone 102. While checking the navigation image displayed in real time on display unit 66, the surgeon moves and rotates the actual jig 210 so that coordinate axis image 15 and coordinate axis image 16 overlap on the screen of display unit 66.

[0110] 9 is a diagram showing an example of a navigation image indicating an attachment position in the first embodiment. Fig. 9 shows an example of a navigation image at a second time point, which is later than the first time point. At the second time point, the jig 210 is moved and rotated by the surgeon, resulting in the coordinate axis image 15 and the coordinate axis image 16 nearly overlapping. In this case, the relative position of the jig 210 and the target attachment position nearly coincide. Furthermore, the relative orientation of the jig 210 and the target attachment orientation nearly coincide.

[0111] Fig. 10 is a diagram showing an example of attachment of the magnetic sensor 301 in the first embodiment. In Fig. 10, the jig 210 is temporarily fixed to the bone 101 (the piriform edge of the skull) using a small screw or the like, with the joint surface 212 of the jig 210 in contact with the bone 101. The jig 220 is temporarily fixed to the bone 102, with the joint surface 222 of the jig 220 in contact with the dentition of the bone 102.

[0112] Here, the orientation (predetermined orientation) of the attachment portion 211 of the jig 210 in a state where it is joined to the bone 101 is the same as the orientation (predetermined orientation) of each attachment portion 221 of the jig 220 in a state where it is joined to the bone 102. This makes it possible to omit calibration of the orientation of each magnetic sensor 301 (initial value of the posture of each bone).

[0113] Next, navigation of bone positions during surgery will be described in more detail. Fig. 11 is a diagram showing an example of a navigation image indicating the relative positions of bones, etc., in the first embodiment. The display unit 66 displays the navigation image generated by the information generation unit 65 at a predetermined frame rate (e.g., 40 fps). In the navigation image, the shape of the bone 101 is represented using an image of a skull model 111. Furthermore, the shape of the bone 102 is represented using an image of a maxilla model 112.

[0114] 11 includes an image of the skull model 111, an image of the maxilla model 112, a display area 401, a coordinate axis image 402, a coordinate axis image 403, and a line image 404. The display area 401 is an area where at least one of numerical information and text information is displayed. The numerical information displayed in the display area 401 represents the difference between the target relative position of the bone 102 and the relative position of the bone 102. The text information displayed in the display area 401 represents the movement direction that reduces the difference between the target relative position of the bone 102 and the relative position of the bone 102.

[0115] The coordinate axis image 402 is represented by three mutually orthogonal line segments (X-axis, Y-axis, and Z-axis). The origin of the coordinate axis image 402 represents the target relative position of the bone 102. The orientation of the coordinate axis image 402 represents the target relative orientation of the bone 102.

[0116] The coordinate axis image 403 is represented by three mutually orthogonal line segments (X-axis, Y-axis, and Z-axis). The origin of the coordinate axis image 403 represents the relative position of the bone 102 with respect to the target relative position of the bone 102. The orientation of the coordinate axis image 403 represents the relative orientation of the bone 102.

[0117] The numerical information representing the difference is, for example, a numerical value representing the distance in millimeters. The text information representing the movement direction is, for example, a character string such as "Left" or "Down." While checking the navigation image, the surgeon may move the bone 102 in the movement direction represented by the text information so that the value of the numerical information decreases. Furthermore, the distance (proximity) from the target relative position to the relative position and the text information "Proximity" may be displayed. Furthermore, the numerical information representing the difference may be the difference (matching rate for each axis) between the orientation of the coordinate axis image 402 and the orientation of the coordinate axis image 403. The matching between the orientation of the coordinate axis image 402 and the orientation of the coordinate axis image 403 indicates that the target relative orientation of the bone 102 and the relative orientation of the bone 102 match.

[0118] The color of the X axis of the coordinate axis image 402 is the same as the color of the X axis of the coordinate axis image 403 (e.g., red). The color of the Y axis of the coordinate axis image 402 is the same as the color of the Y axis of the coordinate axis image 403 (e.g., blue). The color of the Z axis of the coordinate axis image 402 is the same as the color of the Z axis of the coordinate axis image 403 (e.g., green). In addition, the color of the line image 404 connecting the origin (target relative position) of the coordinate axis image 402 and the origin (current relative position of the bone 102) of the coordinate axis image 403 is purple, for example. The length of the line image 404 represents the difference (distance) between the target relative position and the relative position of the bone 102 (maxilla model 112).

[0119] 12 is a diagram showing an example of a navigation image showing the positions of bones, etc. During surgery, the surgeon moves and rotates the bone 102 so that the coordinate axis image 402 and the coordinate axis image 403 overlap, while checking the navigation image displayed in real time on the display unit 66 at a predetermined frame rate.

[0120] The left diagram (part of the navigation image) shown in FIG. 12 represents the position and orientation of the bone 101 (skull model 111) and the position and orientation of the bone 102 (maxilla model 112) at a third time during surgery. The right diagram (part of the navigation image) shown in FIG. 12 represents the position and orientation of the bone 101 (skull model 111) and the position and orientation of the bone 102 (maxilla model 112) at a fourth time after the third time. In the right diagram shown in FIG. 12 , the bone 102 has been moved and rotated by the surgeon, resulting in the coordinate axis image 402 and the coordinate axis image 403 nearly overlapping. In this case, the relative position and orientation of the bone 102 with respect to the position and orientation of the bone 101 are close to the target relative position and target relative orientation predetermined in preoperative planning.

[0121] The orientation of the attachment portion 211 of the jig 210 attached to the target attachment position of the bone 101 is the same as the orientation of the attachment portion 221 of the jig 220 attached to the bone 102 rejoined to the bone 101. In this case, the orientation (tilt) of the magnetic sensor 301-2 inserted into the attachment portion 221 is the same as the orientation of the magnetic sensor 301-1 inserted into the attachment portion 211. This allows the relative positional relationship between the coordinate axis image 402 and the coordinate axis image 403 to be displayed in an intuitively easy-to-understand manner, making navigation surgery extremely easy.

[0122] Furthermore, since the coordinate axis image 402 and the coordinate axis image 403 are each expressed by three-dimensional coordinate axes, the surgeon can intuitively determine whether the relative position and relative orientation of the bone 102 accurately match the target relative position and relative orientation by checking whether the coordinate axis image 402 and the coordinate axis image 403 in the navigation image match. Furthermore, the patient can achieve good occlusion and an aesthetic facial appearance.

[0123] Hereinafter, the relative position of the first sensor (magnetic sensor 301-1) with respect to the target mounting position of the first sensor will be referred to as the “first relative position.” Hereinafter, the relative orientation of the first sensor (magnetic sensor 301-1) with respect to the target mounting orientation of the first sensor will be referred to as the “first relative orientation.”

[0124] Next, an example of the operation of the navigation device 6 when a magnetic sensor is attached to a bone during surgery will be described. Fig. 13 is a flowchart showing a first example of the operation of the navigation device 6 (an example of the operation when a magnetic sensor is attached to a bone) in the first embodiment. The acquisition unit 63 acquires information on the target attachment position and target attachment orientation of the magnetic sensor 301-1 relative to the position and orientation of the magnetic sensor 301-2 from the planning device 2 or the storage device 3 (step S101). The acquisition unit 63 acquires information on the position and orientation of the magnetic sensor 301-1 detected based on the signal of the magnetic sensor 301-1 from the detection device 5 (step S102).

[0125] The derivation unit 64 derives a first relative position and a first relative orientation of the magnetic sensor 301-1 based on the target mounting position and target mounting orientation of the magnetic sensor 301-1 and the position and orientation of the magnetic sensor 301-1 (step S103).

[0126] The information generation unit 65 generates an image of three-dimensional coordinate axes (coordinate axis image 15) representing the target mounting position and target mounting orientation of the magnetic sensor 301-1. The information generation unit 65 generates an image of three-dimensional coordinate axes (coordinate axis image 16) representing the first relative position and first relative orientation of the magnetic sensor 301-1. The information generation unit 65 may generate a jig image 213, an image of the skull model 111, and an image of the maxilla model 112 (step S104). The display unit 66 displays the coordinate axis image 15 and the coordinate axis image 16. The display unit 66 may display the jig image 213, the image of the skull model 111, and the image of the maxilla model 112 (step S105).

[0127] The information generation unit 65 determines whether or not to end the navigation operation. For example, when the surgery is completed, the information generation unit 65 determines to end the navigation operation (step S106). When it is determined to continue the navigation operation (step S106: NO), the information generation unit 65 returns the process to step S102. When it is determined to end the navigation operation (step S106: YES), the information generation unit 65 ends the navigation operation.

[0128] Next, an operation example of the navigation device 6 when bones are moved and rotated relative to each other during surgery will be described. Fig. 14 is a flowchart showing a second operation example (an operation example when bones are moved and rotated relative to each other) of the navigation device 6 in the first embodiment. The acquisition unit 63 acquires information on the shape of the bone 101 (first bone) and information on the shape of the bone 102 (second bone) from the communication unit 61 or the storage unit 62 (step S201). The acquisition unit 63 acquires information on predetermined amounts of movement and rotation for the bone 102 from the communication unit 61 or the storage unit 62 (step S202).

[0129] During surgery, after the magnetic sensor 301 is attached to the bone, the communication unit 61 and the storage unit 62 periodically acquire information on the position and posture of the bone 101 from the communication unit 54. The acquisition unit 63 periodically acquires information on the position and posture of the bone 101 from the communication unit 61 or the storage unit 62 (step S203). The communication unit 61 periodically acquires information on the position and posture of the bone 102 from the communication unit 54. The acquisition unit 63 periodically acquires information on the position and posture of the bone 102 from the communication unit 61 or the storage unit 62 (step S204).

[0130] The derivation unit 64 derives the relative position and orientation of the bone 102 with respect to the position and orientation of the bone 101 based on the information on the position and orientation of the bone 101 and the information on the position and orientation of the bone 102 (step S205). The derivation unit 64 derives the target relative position and orientation of the bone 102 with respect to the position and orientation of the bone 101 based on the relative position and orientation of the bone 102 and predetermined movement amounts and rotation amounts with respect to the initial values ​​of the relative position and relative orientation of the bone 102 (step S206).

[0131] The information generation unit 65 generates predetermined information including a coordinate axis image 402 (image of three-dimensional coordinate axes) representing the target relative position and target relative orientation of the bone 102, based on the target relative position and target relative orientation of the bone 102 with respect to the position of the bone 101. The display unit 66 displays in real time the image of the skull model 111 representing the appearance of the bone 101 according to the position and orientation of the bone 101, and the predetermined information including the coordinate axis image 402 (step S207).

[0132] The information generating unit 65 generates predetermined information including a coordinate axis image 403 (image of three-dimensional coordinate axes) representing the relative position and relative orientation of the bone 102 based on the relative position and relative orientation of the bone 102 with respect to the position of the bone 101. The display unit 66 displays in real time the predetermined information including the image of the maxilla model 112 representing the appearance of the bone 102 according to the relative position and relative orientation of the bone 102 and the coordinate axis image 403 (step S208).

[0133] The information generation unit 65 determines whether or not to end the navigation operation. For example, when the surgery is completed, the information generation unit 65 determines to end the navigation operation (step S209). When it is determined to continue the navigation operation (step S209: NO), the information generation unit 65 returns the process to step S203. When it is determined to end the navigation operation (step S209: YES), the information generation unit 65 ends the navigation operation.

[0134] As described above, the detection unit 53 detects the position and orientation of the magnetic sensor 301-1 based on a signal from the magnetic sensor 301-1 (first sensor) inserted into the attachment portion 211 in a predetermined first orientation with respect to the jig 210 having the joint surface 212 with a surface shaped according to the surface of the bone 101 (for example, the skull). The detection unit 53 also detects the position and orientation of the magnetic sensor 301-2 based on a signal from the magnetic sensor 301-2 (second sensor) inserted into the attachment portion 221 in a predetermined second orientation with respect to the jig 220 having the joint surface 222 with a surface shaped according to the surface of the bone 102 (for example, the maxilla).

[0135] The acquisition unit 63 acquires information on the position and attitude of the magnetic sensor 301-1 detected based on the signal of the magnetic sensor 301-1 from the detection device 5. The acquisition unit 63 acquires information on the target mounting position and target mounting attitude of the magnetic sensor 301-1 relative to the position and attitude of the magnetic sensor 301-2 from the planning device 2 or the storage device 3.

[0136] The derivation unit 64 derives a first relative position and a first relative attitude based on the target mounting position and target mounting attitude and the position and attitude of the magnetic sensor 301-1. The information generation unit 65 generates an image of three-dimensional coordinate axes (coordinate axis image 15) representing the target mounting position and target mounting attitude of the magnetic sensor 301-1. The information generation unit 65 generates an image of three-dimensional coordinate axes (coordinate axis image 16) representing the first relative position and first relative attitude of the magnetic sensor 301-1. The display unit 66 displays the coordinate axis image 15 and the coordinate axis image 16, as exemplified in FIGS. 8 and 9 .

[0137] In this way, the surgeon accurately attaches the magnetic sensor 301-1 in the target attachment orientation to the target attachment position on the actual bone 101 while viewing the coordinate axis image 15 and the coordinate axis image 16, which represent the target attachment position and target attachment orientation of the magnetic sensor 301-1 on the skull model 111. This helps the surgeon accurately move and rotate the bone 102 so that the relative position and relative orientation of the bone 102 become the target relative position and target relative orientation.

[0138] The information generation unit 65 may generate numerical information representing the difference between the target attachment position and the first relative position. The display unit 66 may display the numerical information as exemplified in FIGS. 8 and 9 . The information generation unit 65 may generate text information representing a movement direction that reduces the difference between the target attachment position and the first relative position. The display unit 66 may display the text information as exemplified in FIGS. 8 and 9 . The information generation unit 65 may generate an image of a line connecting the target attachment position and the first relative position. The display unit 66 may display a line image 17 as exemplified in FIGS. 8 and 9 .

[0139] Hereinafter, the relative position of the second bone (bone 102) with respect to the position of the first bone (bone 101) will be referred to as a “second relative position.” Hereinafter, the relative orientation of the second bone with respect to the orientation of the first bone will be referred to as a “second relative orientation.”

[0140] The acquisition unit 63 acquires, from the detection device 5, information on the position and orientation of the bone 101 detected based on a signal from the magnetic sensor 301-1 attached to the bone 101 (e.g., the skull). The acquisition unit 63 acquires, from the detection device 5, information on the position and orientation of the bone 102 detected based on a signal from the magnetic sensor 301-2 attached to the bone 102 (e.g., the maxilla).

[0141] The derivation unit 64 derives a second relative position and a second relative orientation of the bone 102 with respect to the position of the bone 101, based on information on the position and orientation of the bone 101 and information on the position and orientation of the bone 102. The derivation unit 64 derives a target relative position and a target relative orientation of the bone 102 with respect to the position and orientation of the bone 101, based on a predetermined amount of movement with respect to an initial value of the second relative position and a predetermined amount of rotation with respect to an initial value of the second relative orientation.

[0142] The information generation unit 65 generates an image of three-dimensional coordinate axes (coordinate axis image 402) representing the target relative position and target relative orientation. The information generation unit 65 generates an image of three-dimensional coordinate axes (coordinate axis image 403) representing the second relative position and second relative orientation. The display unit 66 displays the coordinate axis image 402 and the coordinate axis image 403, as shown in FIGS. 11 and 12 .

[0143] This allows the surgeon to see the movement and rotation status of the bone 102, thereby assisting the surgeon in accurately moving and rotating the bone 102 so that it is in a predetermined target relative position and target relative posture.

[0144] Second Embodiment The second embodiment differs from the first embodiment in that a magnetic sensor (jig) is also attached to a proximal mandibular bone fragment separated from the mandible. The second embodiment will be described focusing on the differences from the first embodiment.

[0145] 15 is a diagram showing a first example of designating the attachment positions of the magnetic sensors 301 in the second embodiment. The attachment positions of the magnetic sensors 301 are shown for a state before the maxilla model 112 is separated from the skull model 111 on the screen of the display unit 23. The mandible model 113 is a three-dimensional model of the patient's mandible.

[0146] 15, in preoperative planning, the jig 220 illustrated in FIG. 1 is sandwiched between the dentition of the maxilla model 112 and the dentition of the mandible model 113 and bonded to both of them. Mounting position 10 represents the mounting position of the magnetic sensor 301-2 (jig 220) attached to the actual bone 102. Mounting position 11 represents the target mounting position of the magnetic sensor 301-1 attached to the actual bone 101. Mounting positions 12 and 13 represent the target mounting positions of the magnetic sensors 301 attached to the actual mandible. Mounting position 10 is the origin, and mounting positions 11, 12, and 13 are expressed.

[0147] 16 is a diagram showing an example of cutting the bone 103 (mandible) in the second embodiment. During surgery, the surgeon temporarily detaches each magnetic sensor 301 from each bone. The surgeon separates the bone 102 from the bone 101 and cuts the bone 103.

[0148] 17 is a diagram showing an example of the attachment positions of the magnetic sensors 301 after cutting the bone 103 in the second embodiment. The attachment positions of the magnetic sensors 301 are shown for a state in which the bone 102 is separated from the bone 101 and then rejoined to the bone 101.

[0149] 17 , the bone 103 (mandible) is cut into bone 103-1, bone 103-2 (proximal mandible fragment), and bone 103-3 (proximal mandible fragment). The planner determines an attachment position 10 for the first magnetic sensor 301 on the maxilla model 112 and the mandible model 113-1. The planner determines an attachment position 11 for the second magnetic sensor 301 on the skull model 111. The planner determines an attachment position 12 for the third magnetic sensor 301 on the mandible model 113-2. The planner determines an attachment position 13 for the fourth magnetic sensor 301 on the mandible model 113-3. The attachment position 11, the attachment position 12, and the attachment position 13 are expressed with the attachment position 10 as the origin.

[0150] This makes it possible to assist the surgeon in accurately moving and rotating the bone 103, for example, the proximal mandible fragment of the bone 103, so that the relative position and relative orientation of the bone 103 become the target relative position and target relative orientation.

[0151] The second embodiment is suitable for surgery in which a plurality of bones are aligned (for example, surgery to reconstruct an artificial bone in a patient who has lost bone due to osteonecrosis of the jaw caused by cancer, etc.).

[0152] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0153] For example, the number of sensors is not limited to a specific number. For example, by performing navigation using three or more sensors, the surgeon can more accurately align the relative positions and orientations of the bones.

[0154] Furthermore, the navigation surgery in each embodiment is not limited to a specific field of surgery as long as the surgery requires accurate alignment of the relative positions and orientations of each bone. For example, the navigation surgery may be navigation surgery for orthognathic surgery between the maxilla and mandible. Here, a jig (mouthpiece) for the maxilla and a jig (mouthpiece) for the mandible may be created separately. A sensor may be attached to each jig.

[0155] The present invention is applicable to a surgery assistance system.

[0156] 1...navigation system, 2...planning device, 3...storage device, 4...communication line, 5...detection device, 6...navigation device, 10...mounting position, 11...mounting position, 12...mounting position, 13...mounting position, 14...coordinate axis image, 15...coordinate axis image, 16...coordinate axis image, 17...line image, 18...display area, 21...movement processing unit, 22...rotation processing unit, 23...display unit, 51...magnetic field generation unit, 52...acquisition unit, 53...detection unit, 54...communication unit, 61...communication unit 62...storage unit, 63...acquisition unit, 64...derivation unit, 65...information generation unit, 66...display unit, 101...bone, 102...bone, 103...bone, 111...skull model, 112...maxilla model, 113...mandible model, 210...jig, 211...mounting portion, 212...joint surface, 213...jig image, 220...jig, 221...mounting portion, 222...joint surface, 223...jig image, 301...magnetic sensor, 401...display area, 402...coordinate axis image, 403...coordinate axis image, 404...line image

Claims

1. an acquisition unit that acquires information on a position and orientation of a first sensor detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation with respect to a first jig having a surface shaped in accordance with a surface of a first bone, and information on a target mounting position and a target mounting orientation of the first sensor relative to the position and orientation of the second sensor detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation with respect to a second jig having a surface shaped in accordance with a surface of a second bone; a derivation unit that derives a first relative position and a first relative orientation of the first sensor with respect to the target mounting position and the target mounting orientation based on the target mounting position and the target mounting orientation and the position and orientation of the first sensor; an information generating unit that generates an image on a three-dimensional coordinate axis representing the target mounting position and the target mounting attitude, and an image on a three-dimensional coordinate axis representing the first relative position and the first relative attitude; a display unit that displays an image of a three-dimensional coordinate system representing the target mounting position and the target mounting attitude, and an image of a three-dimensional coordinate system representing the first relative position and the first relative attitude; A navigation system comprising:

2. The second jig is a dental splint. The navigation system of claim 1 .

3. The information generating unit generates numerical information representing a difference between the target mounting position and the first relative position, The display unit further displays the numerical information. The navigation system of claim 1 .

4. the information generating unit generates character information representing a moving direction that reduces a difference between the target mounting position and the first relative position, The display unit further displays the character information. The navigation system of claim 1 .

5. The information generating unit generates an image of a line connecting the target mounting position and the first relative position, The display unit further displays an image of the line. The navigation system of claim 1 .

6. The sensor is a magnetic sensor. The navigation system of claim 1 .

7. the first bone is a skull; The second bone is the maxilla. The navigation system of claim 1 .

8. the acquisition unit acquires information on a position and a posture of the first bone detected based on a signal of the first sensor attached to the first bone, and information on a position and a posture of the second bone detected based on a signal of the second sensor attached to the second bone, the derivation unit derives a second relative position and a second relative orientation of the second bone with respect to the position of the first bone based on information on the position and orientation of the first bone and information on the position and orientation of the second bone, and derives a target relative position and a target relative orientation of the second bone with respect to the position and orientation of the first bone based on a predetermined movement amount with respect to an initial value of the second relative position and a predetermined rotation amount with respect to an initial value of the second relative orientation; the information generation unit generates an image of three-dimensional coordinate axes representing the target relative position and the target relative orientation, and an image of three-dimensional coordinate axes representing the second relative position and the second relative orientation, the display unit displays an image of three-dimensional coordinate axes representing the target relative position and the target relative attitude, and an image of three-dimensional coordinate axes representing the second relative position and the second relative attitude. The navigation system of claim 1 .

9. an acquisition unit that acquires information on a position and orientation of a first bone detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation with respect to a first jig having a surface shaped according to a surface of the first bone, and information on a position and orientation of a second bone detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation with respect to a second jig having a surface shaped according to a surface of a second bone; a derivation unit that derives a relative position and a relative orientation of the second bone with respect to a position of the first bone based on information on a position and an orientation of the first bone and information on a position and an orientation of the second bone, and that derives a target relative position and a target relative orientation of the second bone with respect to the position and orientation of the first bone based on a predetermined amount of movement with respect to an initial value of the relative position and a predetermined amount of rotation with respect to an initial value of the relative orientation; an information generating unit that generates an image on a three-dimensional coordinate axis representing the target relative position and the target relative orientation, and an image on a three-dimensional coordinate axis representing the relative position and the relative orientation; a display unit that displays an image of a three-dimensional coordinate system representing the target relative position and the target relative attitude, and an image of the three-dimensional coordinate system representing the relative position and the relative attitude; A navigation system comprising:

10. a mounting portion into which the sensor is inserted in a predetermined orientation; A surface shaped to match the surface of the skull bone to be joined. A first jig having a mounting portion into which the sensor is inserted in a predetermined orientation; A surface shaped according to the surface shape of the bone on the side of the teeth to be attached. and a second jig having jig.

11. the first jig has a first mounting portion into which the first sensor is inserted in a first orientation that is predetermined with respect to the first jig, and the first surface has a shape corresponding to a surface of the first bone on the skull side; the second jig has a second mounting portion into which the second sensor is inserted in a second orientation that is predetermined with respect to the second jig, and a second surface having a shape corresponding to a surface shape of a bone on the second dentition side; a direction of the first sensor inserted into the first mounting portion of the first jig in a state where the first jig is joined to the bone on the skull side and a direction of the second sensor inserted into the second mounting portion of the second jig in a state where the second jig is joined to the bone on the dentition side are the same; The jig according to claim 10.

12. On the computer, acquiring information on a position and orientation of a first sensor detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation with respect to a first jig having a surface shaped in accordance with a surface of a first bone, and information on a target mounting position and a target mounting orientation of the first sensor relative to a position and orientation of a second sensor detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation with respect to a second jig having a surface shaped in accordance with a surface of a second bone; deriving a first relative position and a first relative orientation of the first sensor with respect to the target mounting position and the target mounting orientation based on the target mounting position and the target mounting orientation and the position and orientation of the first sensor; generating an image on a three-dimensional coordinate axis representing the target mounting position and the target mounting attitude, and an image on a three-dimensional coordinate axis representing the first relative position and the first relative attitude; a step of displaying an image of a three-dimensional coordinate axis representing the target mounting position and the target mounting attitude, and an image of a three-dimensional coordinate axis representing the first relative position and the first relative attitude; A program for executing the above.

13. On the computer, acquiring information on the position and orientation of a first bone detected based on a signal from a first sensor inserted into a mounting portion of a first jig in a predetermined first orientation with respect to a first jig having a surface shaped in accordance with a surface of a first bone, and information on the position and orientation of a second bone detected based on a signal from a second sensor inserted into a mounting portion of a second jig in a predetermined second orientation with respect to a second jig having a surface shaped in accordance with a surface of a second bone; a step of deriving a relative position and a relative orientation of the second bone with respect to a position of the first bone based on information on a position and an orientation of the first bone and information on a position and an orientation of the second bone, and deriving a target relative position and a target relative orientation of the second bone with respect to the position and orientation of the first bone based on a predetermined amount of movement with respect to an initial value of the relative position and a predetermined amount of rotation with respect to an initial value of the relative orientation; generating an image on a three-dimensional coordinate axis representing the target relative position and the target relative orientation, and an image on a three-dimensional coordinate axis representing the relative position and the relative orientation; a step of displaying an image of a three-dimensional coordinate axis representing the target relative position and the target relative attitude, and an image of a three-dimensional coordinate axis representing the relative position and the relative attitude; A program for executing the above.