JP6772027B2 - Accuracy verification tool for surgical support equipment - Google Patents

Description

The present invention relates to a tool for verifying the accuracy of a surgical support device.

In the field of orthopedics, surgery to replace artificial joints is performed to treat bones that have been deformed due to congenital anomalies or malunions after fractures.

The installation position and installation angle of the artificial joint have a great influence on the postoperative range of action of the patient and the period of use of the artificial joint. For this reason, a surgical support device capable of displaying the position and angle of an artificial joint or a surgical instrument to be installed on a bone at the time of surgery in real time has come to be used.

The surgical support device sets the installation position and installation angle of the artificial joint on dedicated software using medical images such as CT (Computed Tomography), MRI (Magnetic Resonance Imaging), and CR (Computed Radiography) before surgery. It is a device that supports this.

Specifically, a 3D (three-dimensional) bone model is created on preoperative planning software using medical images obtained by CT, MRI, CR, or the like.

Then, at the time of surgery, a plurality of characteristic specific parts of the actual patient's bone are recognized by the camera of the surgery support device using a dedicated tool, so that the position with the 3D bone model of the preoperative plan is recognized. Make a match. As a result, the surgical support device displays the preoperatively planned position and angle and the current positional relationship of the instrument on the monitor screen in real time. In this way, the operator can excise the bone and install the artificial joint while referring to the display screen.

At the time of surgery, a position-detecting instrument, called a reference, on which a plurality of balls that are irradiated and reflected by infrared rays are arranged is attached to the patient's bone and surgical instrument. Then, the relative positions of the bone and the instrument are displayed on the monitor screen by using the two cameras of the surgical support device or the sensors that specify the positions. When two cameras are used, the position of the reference is calculated by using the parallax of the reference image obtained by each camera. In this way, the surgical support device enables the surgeon to install an artificial joint close to the preoperative plan.

However, the method of causing the surgery support device to recognize the position of the bone after attaching the reference to the bone differs depending on the model of the surgery support device, and the accuracy of alignment also differs.

As a method of alignment, for example, using a dedicated pointing tool, multiple specific parts of the bone, such as the upper right anterior iliac spine, the upper left anterior iliac spine, and the scrotum, are pointed at the camera of the surgical support device and preoperatively. A bone model called a bone model created using CT and MRI scan data of the above, which registers a specific part of the indicated bone on the bone figure displayed on the monitor screen, or aligns the bone. There is a method of registering a specific part of the bone pointed to on a virtual bone model created by calculating the positional relationship and size on the spot and performing alignment. Alternatively, there is also one in which the parallax image acquired by the C-arm, CT, MRI, CR or the like during the operation is used, and the alignment is performed by calculating in the operation support device.

Further, not only the relative position between the bone and the instrument as described above is displayed on the monitor screen of the surgical support device, but also the development of a technique for cutting the bone by a surgical cutting robot is in progress. However, there is a report that there is an error in the surgical result using such a device with the preoperative plan, and it is necessary to establish a method for confirming the accuracy of alignment.

Surgical support devices and surgical cutting robots are manufactured by multiple manufacturers, and each model recognizes the positional relationship of the patient's bones during surgery based on a different principle. According to the Japan Computer-Assisted Orthopedic Surgery (CAOS) Study Group, CAOS International, etc., there are several errors in the surgical results using these devices, and there are many bones in Japanese. There are reports of overseas product devices that have been pointed out as unsuitable for cases with strong deformities, and it is important to verify the accuracy of the devices.

On the other hand, in recent years, new product development in this field has been actively promoted in Japan and overseas. However, application for medical devices requires many experimental results to prove safety, and the cost and time required for development are high, so the introduction of innovative technologies is delayed compared to other fields. There is. Therefore, in order to promote the introduction of new technology safely and smoothly, it was necessary to establish a method that enables simple and objective accuracy verification regardless of the model.

By the way, an artificial joint is a medical device embedded in a bone for the treatment of deformed bone. As the material of the artificial joint, metal, ceramics, polyethylene and the like are used.

A hemispherical cup is installed on the pelvic side, and an artificial joint called a stem that matches the shape of the spinal cord is installed on the femur side. A head ball and a liner that has both slidability and cushioning properties are fitted between the cup and the stem. Since the liner and the head ball can slide smoothly, the patient after surgery can walk.

The cup is installed near the position where the head of the femur was originally located, in a direction of about 40 degrees with the vertical line when viewed from the front view. As described above, the installation position and installation angle of the artificial joint are important because they also affect the postoperative range of action and the usable period of the artificial joint.

Conventional surgical support-related techniques include those described in the following Patent Documents 1 to 6.

Japanese Unexamined Patent Publication No. 2014-97220 Japanese Unexamined Patent Publication No. 2006-122591 Japanese Unexamined Patent Publication No. 2014-30536 Special Table 2006-501972 Japanese Unexamined Patent Publication No. 2011-172920 JP-A-2015-42252

By the way, some surgical support devices have been reported to be unsuitable for cases with strong bone deformities as described above, and there have also been reports that an error has occurred between them and the preoperative plan. However, conventional surgical support-related technology has not been able to perform simple and highly reliable accuracy verification regardless of the model of the device.

Conventionally, when verifying the accuracy of a surgical support device, after implanting an artificial joint in an actual patient using the surgical support device, another image is taken after surgery by CT, MRI, CR, etc., and image analysis software is used. It was necessary to measure the installation position and installation angle of the artificial joint with respect to the pelvis. However, the cost of imaging after surgery, the time required for image analysis, and the workload were extremely large.

Furthermore, the reference plane of the pelvis, which was used as the reference when installing the artificial joint in the preoperative plan, and the reference plane of the pelvis, which was used as the reference when analyzing the postoperative images, could not be completely matched, thereby. It had a fatal problem of measurement error.

In view of the above circumstances, an object of the present invention is to provide a surgical support device with an accuracy verification tool capable of performing simple and reproducible accuracy verification.

The accuracy verification tool of the surgical support device of the present invention
Medical image data including information on the cross section of the bone, information for specifying the position and orientation of the reference plane in the bone, and information indicating the installation position and installation angle of the artificial joint with respect to the reference plane.
A bone model containing the information indicating the installation position and the installation angle of the artificial joint with respect to the reference plane.
It is characterized by having.

According to the accuracy verification tool of the surgical support device of the present invention, it is possible to perform simple and reproducible accuracy verification on the surgical support device.

The figure which shows the reference plane APP (Anterior Pelivic Plane) which passes through the upper left anterior iliac spine, the upper right anterior iliac spine, the left pubic tubercle, and the right pubic tubercle of the pelvis. The center of the sacrum and the pubic symphysis are formed on a coordinate system constructed by rotating the pelvis with the axis connecting the left and right sacral nodules of the pelvis as the horizontal reference, and further rotating the axis connecting the center of the sacrum and the pubic symphysis with the midline as the reference. The figure which shows the FPP (Functional Pelvic Plane) which consists of the plane orthogonal to the street CT, MRI, CR sleeper, and the plane orthogonal to the plane. The figure which shows the femoral plane which consists of the femoral axis which connects the trochanteric fossa and the most distal end of the intercondylar part, and the posterior condyle plane which passes through the last end of the greater trochanter, the left posterior condyle, and the right posterior condyle. The figure which shows the reference for a acetabular reamer, the reference for a pelvis, the reference for a driving instrument, the reference for a femur, and the reference for a pointer. A perspective view showing that a plurality of characteristic specific points of the pelvis are pointed at a camera of a surgical support device with a pointer to recognize the position, and alignment is performed with a bone model of a preoperative plan. The perspective view which shows that the operation support device recognizes the position and angle of the acetabular reamer to which the reference for acetabular reamer is attached and displays it on a monitor screen. The figure which shows the DICOM data set which is a set of a plurality of image data which sliced the cross section of a human torso. The figure which shows the state which the CAD system displayed the 3D model of the pelvis on the screen of the CAD system using the DICOM data set. DICOM data with embedded three-dimensional model consisting of a triangular pyramid pointing to the anterior superior iliac spine, pubis, etc., a cube indicating the orientation of the reference plane, and a cylinder specifying the installation position and angle of the artificial joint, output from the CAD system. The figure which shows the set. The perspective view which shows the pelvis model provided with the cylinder which shows the installation position and installation angle of an artificial joint. The figure which shows the pelvis which read the DICOM data set in which the 3D model was embedded with the preoperative planning software of the operation support device, and displayed it in 3D on the monitor screen. A perspective view showing an intraoperative operation using a surgical support device and a pelvic model. A 3D model femur is generated on the monitor screen of the CAD system, and the posterior condyle plane and posterior condyle plane connecting the posterior margin of the greater trochanter, the left posterior condyle, and the apex of the triangular pyramid pointing to the right posterior condyle are used as a reference. The figure which showed the state of generating the cylinder which specifies the installation position and the installation angle of the artificial joint (stem) of. FIG. 3 is a perspective view showing a DICOM data set of a medical image including a femur in which a three-dimensional model such as a triangular pyramid or a cylinder output from a CAD system is embedded. The perspective view which shows the femur model created by inputting the output DICOM data set into a 3D printer. A perspective view showing a state in which a DICOM data set in which a three-dimensional model is embedded is read by the preoperative planning software of the surgical support device 20. A perspective view showing a state of performing an intraoperative operation using a surgical support device and a femur model.

Hereinafter, the accuracy verification tool of the surgical support device according to the embodiment of the present invention will be described with reference to the drawings. The same components are designated by the same reference numerals, and duplicate description will be omitted. In the case of a figure showing a 3D model of a bone on a CAD system, a straight square frame, in the case of a figure showing a 3D model of a bone on the preoperative planning software of a surgical support device, a double straight square frame, a real object. In the case of the figure showing, there is no frame.

First, before explaining the present embodiment, an outline of an actual operation of replacing a patient's joint with an artificial joint by using a surgical support device will be described.

1) Make preoperative preparations using a surgical support device. Specifically, the preoperative planning software of the surgical support device is activated to make a surgical plan. The medical image data by the DICOM data set described later is read, and the 3D model of the pelvis is displayed on the monitor screen by the preoperative planning software.

2) On the 3D model displayed on the monitor screen, the pelvis plane and the femur plane are set as the reference planes when the artificial joints (cups, stems) are installed. As a commonly used pelvic plane, for example, APP (Anterior Pelvic Plane) and FPP (Functional Pelvic Plane) exist. The APP is a plane passing through the upper right anterior iliac spine 12, the upper left anterior iliac spine 13, the right pubic tubercle 14, and the left pubic tubercle 15 of the pelvis, as shown in FIG. The FPP is the right ischium of the pelvis as shown in FIG. 2 (a) which is a front view and FIG. 2 (b) which is a right side view based on a table 23 for photographing CT, MRI, CR and the like. On the coordinate system constructed by rotating the pelvis so that the axis connecting the nodule 61 and the left ischial nodule 62 becomes the horizontal reference, and further rotating the axis connecting the sacral center 63 and the pubic symphysis 64 so as to refer to the midline. A plane that passes through the sacral center and the pubic symphysis and is orthogonal to the CT, MRI, and CR sleepers, and a plane that is orthogonal to that plane. The femoral plane is a posterior condyle plane that passes through the posterior end of the greater trochanter 73, the left posterior condyle 74, and the right posterior condyle 75, as shown in FIG. Further, as shown in FIG. 3A, which is a front view, the axis passing through the trochanteric fossa 71 and the distal end 72 of the intercondylar portion is set as the femoral axis.

3) Set the installation angle, installation position, and size of the artificial joint (cup) based on APP and FPP.

4) Set the reference plane, coordinate system, and axis of the femur, and set the installation angle, installation position, and size of the artificial joint (stem).

5) Start the surgery using the surgery support device. In a state where the acetabulum in the patient's pelvis and the head of the tip of the femur are fitted, the pelvis and the femur are separated by cutting between the femur and the head of the tip of the femur. Furthermore, the head of the bone fitted to the acetabulum of the pelvis is removed.

6) Align the 3D model of the bone displayed on the monitor screen of the surgical support device with the patient's pelvis and femur.

7) Check the relative positional relationship between the current pelvis and the acetabular reamer displayed on the monitor screen of the surgical support device, and adjust the inner wall of the pelvic acetabulum so that it matches the installation angle and installation position set in the preoperative plan. Shave it into a hemisphere with a acetabular reamer.

8) A metal cup-shaped artificial joint (cup) is housed in the acetabulum of the pelvis and bolted, and a polyethylene liner is fitted into the artificial joint (cup).

9) Check the relative positional relationship between the current femur and the medullary reamer displayed on the monitor screen of the surgical support device, and in the longitudinal direction of the femur so that it matches the installation angle and installation position set in the preoperative plan. The inner wall of the medullary cavity existing along the medullary cavity is shaved by inserting a medullary cavity reamer and rotating it to increase the radius of the medullary cavity.

10) Check the relative positional relationship between the current femur and the rasp (a device that cuts the bone in the same shape as the artificial joint (stem)) displayed on the monitor screen of the surgical support device, and set the installation angle in the preoperative plan. Insert a raspe into the medullary space of the femur to match the placement position and scrape the medullary space.

11) Check the relative positional relationship between the current femur and medullary reamer displayed on the monitor screen of the surgical support device, and place it in the medullary space of the femur so that it matches the installation angle and installation position set in the preoperative plan. , Insert a rod-shaped artificial joint (stem) made of metal.

12) A metal or ceramic artificial head ball is attached to the tip of the artificial joint (stem).

13) The operation is completed by fitting the artificial head ball attached to the tip of the femur into the liner in the artificial joint (cup) of the pelvis.

Here, the roles of the surgical support device and the reference during the above work will be described.

As described above, the reference has a plurality of balls that are irradiated with infrared rays and reflected, and are attached to the bone and the surgical instrument at the time of surgery to detect their respective positions. This makes it possible to display the positions of the bone and the surgical instrument on the monitor screen of the surgical support device.

For example, the reference 1 for the acetabulum reamer in which the infrared reflective ball 2 is arranged as shown in FIG. 4 (a) and the pelvis in which the infrared reflective ball 4 is arranged as shown in FIG. 4 (b). Reference 3, reference 5 for driving equipment in which the infrared reflective ball 6 is arranged as shown in FIG. 4 (c), and thigh in which the infrared reflective ball 8 is arranged as shown in FIG. 4 (d). A bone reference 7 and a pointer reference 31 on which the infrared reflective ball 9 is arranged as shown in FIG. 4 (e) are used. As described above, a plurality of types of references are used so that the surgical support device can discriminate between the instrument and the bone due to the different arrangement of the infrared reflective balls.

As described above, the surgical support device displays a 3D bone model on the monitor screen 21 shown in FIG. 5 using medical images such as CT, MRI, and CR before surgery, and artificial joints for the patient's pelvis 11A. Supports setting the installation position and installation angle of.

Specifically, at the time of surgery, as shown in FIG. 5, a plurality of characteristic identifications of the patient's pelvis 11A to which the pelvic reference 3 is attached toward the two cameras 22 of the surgical support device 20. The location, for example, the upper left anterior iliac spine, the upper right anterior iliac spine, the pubis, the acetabulum, etc., are pointed to by the pointer 31 to recognize the position, and the alignment is performed with the bone model of the preoperative plan. Since images with parallax are obtained from the two cameras 22, the surgery support device 20 can calculate the position from the surgery support device 20 to each reference.

Next, as shown in FIG. 6, by attaching the acetabular reamer reference 1 to the acetabular reamer 32, the surgical support device 20 recognizes the position and angle of the acetabular reamer 32 and displays it on the monitor screen 21. Can be displayed.

In this way, the surgical support device 20 displays the positional relationship between the position and angle of the pelvis 11A and the surgical instrument such as a reamer on the monitor screen 21 in real time.

Next, a procedure for verifying the accuracy of the surgical support device will be described using the accuracy verification tool of the surgical support device according to the present embodiment.

1) Photographed by CT, MRI, CR, etc. based on a medical image format called DICOM (Digital Imaging and Communication in Medicine) on a CAD (Computer Aided Design) system (a system capable of creating a 3D model) (not shown). Read the DICOM dataset of scanned images of any patient. As shown in FIG. 7, the DICOM data set is a set of a plurality of image data obtained by slicing a cross section of a human body including a site to be operated on with a thickness of, for example, 0.5 mm. Each image data is configured in a matrix such as 512 pixels × 512 pixels, and CT values, MRI values, CR values, etc. are assigned in pixel units.

2) The CAD system uses the DICOM data set to construct a 3D model of the pelvis by discriminating it as a bone if the CT value assigned to each matrix exceeds a certain threshold, and as a space if it does not exceed a certain threshold. Display a 3D model of the pelvis on the screen of the CAD system as shown in. Further, as the pelvic plane, for example, APP (Anterior Pelvic Plane) or FPP (Functional Pelvic Plane), a three-dimensional model such as a triangular pyramid described later for identifying APP or FPP, and an installation position and installation of an artificial joint (cup, stem, etc.) A three-dimensional model such as a cylinder for specifying an angle and a three-dimensional model such as a cube for confirming the orientation of APP or FPP are generated.

3) Output the DICOM data set with the embedded model from the CAD system. As shown in FIG. 9A, this DICOM data set consists of image data obtained by slicing a plurality of 3D model pelvis 11B displayed on the screen of the CAD system, and FIGS. 9A and 9B. As shown in, right upper anterior iliac spine 12, upper left anterior iliac spine 13, right pubic tubercle 14, triangular pyramid pointing to left pubic tubercle 15, cube 16 parallel to APP, which is the pelvic plane, artificial joint. A column 17A is added to specify the installation position and installation angle of (cup, stem, etc.). The 3D model data of the pelvis to which this 3D model is added is also output separately as a 3D printer file (STL file).

4) Input the STL file to a 3D printer to create a pelvis model made of materials such as plaster. As shown in FIG. 10, the created pelvis model 11C is provided with a cylinder 17B corresponding to the cylinder 17A shown in FIG. 9A so that the installation position and installation angle of the artificial joint can be known. ing. The cylinder 17B is provided by inserting a metal round bar into the pelvis model 11C, or is provided as a plaster model with a 3D printer. In either case, the cylinder 17B has the same position and angle as the cylinder 17A of the 3D model data.

5) The DICOM data set in which the three-dimensional model is embedded is read by the preoperative planning software of the surgical support device, and the pelvis is displayed in 3D on the monitor screen as shown in FIG. On this 3D screen, as a three-dimensional model embedded in the pelvis, for example, a triangular pyramid showing an upper right anterior iliac spine 12, an upper left anterior iliac spine 13, a right pubic tubercle 14, and a left pubic tubercle 15 are displayed. However, the meaning of this triangular pyramid in the surgical support device has not yet been recognized at this point. Therefore, the apex of each triangular pyramid is associated with the location of, for example, the upper right anterior iliac spine 12, the upper left anterior iliac spine 13, the right pubic tubercle 14, and the left pubic tubercle 15 that specify the reference plane of APP. sign up. Thereby, for example, the same reference plane as the reference plane of APP set on CAD can be set on the surgery support device. Based on this set reference plane, the installation position and installation angle of the artificial joint are set.

6) As shown in FIG. 12, the surgical support device 20 and the pelvic model 11C are used to perform the intraoperative operation. On the monitor screen 21 of the surgery support device 20, a screen corresponding to the installation of the artificial joint is displayed. Point the upper right anterior iliac spine 12, the upper left anterior iliac spine 13, the right pubic tubercle 14, and the left pubic tubercle 15 of the pelvic model 11C with a pointer 31 (not shown) to the two cameras 22 of the surgical support device 20. Recognize each position and perform alignment. The acetabular reamer 32 to which the acetabular reamer reference 1 is attached is installed so as to be parallel to the cylinder 17B provided on the pelvis model 11C indicating the direction of the artificial joint. As a result, the position and angle of the acetabular reamer 32 with respect to the pelvis model 11C are recognized and displayed on the monitor screen 21 of the surgery support device 20. As a result, if there is a deviation between the angle and position of the cylinder 17B previously installed in the pelvis model 11C and the angle and position of the acetabular reamer 32 displayed on the monitor screen 21, this deviation is used as the surgical support device. It can be evaluated as an error of the accuracy verification result of 20. For example, as shown in FIG. 12, when the pelvis model 11C is viewed from the front, the angle of the cylinder 17B with respect to the pelvis model 11C is 40 degrees, and the angle of the acetabular reamer 32 is displayed as 41 degrees. , The error is 1 degree. Further, when the angle of the cylinder 17B with respect to the pelvis model 11C is 15 degrees and the angle of the acetabular reamer 32 is displayed as 17 degrees when the pelvis model 11C is viewed from the right side, the error is 2 degrees.

In the above embodiment, a case where an artificial joint (cup) is installed on the pelvis has been described as an example. However, this embodiment is not limited to the pelvis and can be similarly applied to other joints. In the following embodiment, a case where an artificial joint (stem) is installed on the femur will be described as an example.

1) Start the 3D model creation software on the CAD system. A DICOM data set consisting of a plurality of scanned images taken by CT, MRI, CR, etc. showing the femur of a patient is read.

2) As shown in FIG. 13, a 3D model femur 41A is generated and displayed on the monitor screen of the CAD system. After passing through the apex of the triangular pyramid as a three-dimensional model pointing to the posterior edge 26 of the large trochanter of the thighbone 41A, the triangular pyramid as a three-dimensional model pointing to the left posterior condyle 27, and the triangular pyramid pointing to the right posterior condyle 28. A cylinder is generated as a three-dimensional model for specifying the installation position and installation angle of the artificial joint (stem) with reference to the condyle plane and the posterior condyle plane. For example, as shown in FIG. 13, a cylinder 42 indicating the long axis of the artificial joint (stem), a cylinder 43 indicating the rotation direction of the artificial joint (stem), and a cylinder 44 indicating the neck axis of the artificial joint (stem) are provided. Generate. The neck axis is the neck axis of the stem shown in FIG. 16 (b), and generally has an angle of about 130 degrees with respect to the long axis of the stem. The head is placed on the extension of the cervical axis.

3) From the CAD system, as shown in FIG. 14, the femur 41A in which a three-dimensional model consisting of the posterior edge of the greater trochanter 26, the left posterior condyle 27, the triangular pyramid pointing to the right posterior condyle 28, and the columns 42 to 44 was embedded. It is output as a DICOM data set of medical images including the above and an STL file corresponding to a file for a 3D printer.

4) Input the output STL file to a 3D printer, and create a femur model 41B from a material such as plaster. As shown in FIG. 15, the femur model 41B is provided with the above-mentioned cylinders 42 to 44 as a three-dimensional object whose installation position and installation angle of the artificial joint can be known. The cylinders 42 to 44 are provided by inserting a metal round bar into the femur model 41B, or are provided as a plaster model with a 3D printer. In either case, the cylinders 42 to 44 have the same positions and angles as the cylinders 42 to 44 in the 3D model data.

5) The DICOM data set of the medical image in which the three-dimensional model is embedded is read by the preoperative planning software of the surgery support device 20. As a result, as shown in FIG. 16A, a 3D model femur 41A having the same shape and positional relationship as the femur model 41B and the cylinders 42 to 44 is created. The femur 41A of this 3D model includes a triangular pyramid that identifies the posterior margin of the greater trochanter 26, the left posterior condyle 27, and the right posterior condyle 28. In the surgical support device 20, the vertices of the triangular pyramid are registered as the posterior edge of the greater trochanter 26, the left posterior condyle 27, and the right posterior condyle 28, respectively. As a result, it is possible to set the same posterior condyle plane that does not deviate from the femur model 41B even on the preoperative planning software. Further, as shown in FIG. 16B, a 3D model artificial joint (stem) 45 having a shape suitable for the medullary space of the femur 41A is inserted into the femur 41A side. The femur 41A of the 3D model includes cylinders 42 to 44 that specify the installation position and installation angle of the artificial joint (stem) to be inserted into the femur 41A. Therefore, even on the preoperative planning software, it is possible to specify the installation position and installation angle that are exactly the same as those of the femur model 41B, and to carry out the preoperative planning.

6) As shown in FIG. 17, the surgical support device 20 and the femur model 41B are used to perform the intraoperative operation. On the monitor screen 21 of the surgery support device 20, a screen corresponding to the installation of the artificial joint is displayed. A femur reference 7 is attached to the femur model 41B. Point the posterior margin of the greater trochanter 26, the left posterior condyle 27, and the right posterior condyle 28 of the femur model 41B with pointers (not shown) to recognize their positions toward the two cameras 22 of the surgical support device 20. And perform alignment. Of the cylinders 42 to 44 indicating the installation direction of the artificial joint (stem) 45 provided on the femur model 41B, the artificial joint (stem) to which the reference 5 for a driving instrument is attached to the cylinder 42 indicating the insertion direction. The driving device 51 is installed so that the driving device 51 of 45 is parallel to each other. As a result, the position and angle of the driving device 51 with respect to the femur model 41B are recognized and displayed on the monitor screen 21 of the surgery support device 20. As described above, the femur model 41B is provided with a cylinder 42 that specifies the installation position and installation angle of the artificial joint (stem) 45. Therefore, by installing the driving instrument 51 to which the driving instrument reference 5 is attached in parallel with the cylinder 42, if there is no error, the installation position displayed on the monitor screen 21 of the surgical support device 20. The installation angle should be the same as the preoperative plan. However, if there is a discrepancy between the angle of the cylinder 42 previously installed in the femur model 41B and the angle of the driving instrument 51 displayed on the monitor screen 21, this misalignment is the accuracy verification of the surgical support device 20. It can be evaluated as an error. For example, when the femur model 41B is viewed from the front, the angle of the cylinder 42 with respect to the femur model 41B is x degrees, and the angle of the driving device 51 is displayed as x + 2 degrees, the error is 2 degrees. In this way, on the monitor screen 21 of the surgical support device 20, the error angle between the target angle of the artificial joint (stem) 45 planned before the operation and the current angle of the driving instrument 51 is displayed. ..

As described above, when the accuracy of the surgical support device is evaluated by the conventional method, CT, MRI, and CR are performed after the artificial joint (stem) is driven into the femur as displayed on the monitor screen of the surgical support device. It was necessary to take pictures with the above and measure the installation position and installation angle of the artificial joint (stem) with respect to the femur using image analysis software.

On the other hand, according to the present embodiment, by using the femur model and the DICOM data set, after the artificial joint (stem) is driven, the image is taken by CT, MRI, CR, etc., and the error using the image analysis software. Since the work of measuring the data can be omitted, the accuracy of the surgical support device can be easily verified.

As described above, this embodiment can be applied to the installation of artificial joints on the pelvis and femur, but can also be applied to the installation of artificial joints on other joints. The following is a general procedure in the embodiment to which the present invention is applied when the artificial joint is installed on any joint.

1) Start the software that creates a 3D model on a CAD system that handles medical images, and read the DICOM data set of scanned images of any patient.

2) On the CAD system, create a 3D model of the bone using the DICOM data set and display it on the monitor screen. Furthermore, on the 3D model of the bone, a three-dimensional model such as a triangular pyramid that specifies a plurality of characteristic parts for obtaining a reference plane of the bone, and a three-dimensional model such as a cylinder for specifying the installation position and the installation angle of the artificial joint. Alternatively, a three-dimensional model showing the position and angle at which the bone is cut is placed and embedded.

3) Output the DICOM data set with the embedded model from the CAD system.

4) Using the output DICOM data set, create a bone model with a 3D printer or the like. A three-dimensional model created by CAD is added to the created bone model.

5) The same DICOM data set as in 4) is read into the surgery support device to be verified for accuracy and displayed in 3D on the monitor screen to perform preoperative planning. In the preoperative plan, the reference plane, the installation position of the artificial joint, the installation angle, the position to cut the bone, and the angle are registered with reference to the three-dimensional model added to the bone displayed in 3D.

6) Using the surgical support device whose accuracy is to be verified, perform intraoperative operations by using a bone model as a patient. In the intraoperative operation, the installation position, installation angle, bone cutting position, and angle of the instrument or artificial joint are displayed on the monitor screen of the surgical support device. By examining the difference between this position and angle and the position and angle of the three-dimensional model added in the bone model, the accuracy of the surgical support device can be verified.

The factors of the error inherent in the surgical support device will be described below.

First, regarding the definition of error, the installation angle and installation position of the artificial joint (cup) and (stem) displayed on the monitor screen of the surgical support device, and the medical images such as CT, MRI, and CR after surgery are displayed. It is defined as the deviation existing between the artificial joint (cup), the actually installed angle of the (stem), and the installation position, which are acquired and measured by image analysis.

Then, as the type of error, an error caused by the limit of the performance of the camera of the surgical support device, an error inherent in the calculation algorithm when the surgical support device performs alignment, and the like can be considered. The factors of each error in the CT-based surgery support device, the CT-based fluoromatching surgery support device, and the imageless surgery support device having different bone alignment methods will be described in detail below.

The error factors of the CT-based surgery support device using the CT DICOM data set are as follows.

It is difficult for the operator to accurately register the actual bone surface when instructing registration on the monitor screen of the surgical support device when aligning the 3D model of the bone with the actual bone position. , An error occurs. That is, it is easy for an operation error to occur when the pointer accurately points to the position indicated by the point displayed on the monitor screen.

In addition, when the camera of the surgical support device cannot recognize the bone model or the reference attached to the bone cutting tool such as a reamer from the front, the position displayed on the monitor screen of the surgical support device is the bone model or It may deviate from the actual position of the bone cutting tool, causing an error.

In order to accurately recognize the position of the reference, the optimum distance between the camera of the surgical support device and the reference is within a range of about 2 m. Therefore, if the distance is more than 2 m, the surgical support device cannot accurately recognize the position of the reference. In addition, even if the range exceeds 2 m, there is a problem that it is not clear whether the inaccuracies gradually or suddenly become inaccurate as the distance increases.

The error factors of the CT-based fluoromatching surgery support device are as follows.

For alignment, a 3D model of the bone created from the DICOM data set of preoperative CT and two parallax CR images of the actual bone taken with the C arm immediately before the operation are used for calculation. However, the CR image acquired by the C arm has different imaging conditions from the DICOM data set of the preoperative CT used for creating the 3D model of the bone. Therefore, a deviation may occur when calculating the alignment. However, it is considered that the error is smaller than the alignment method in which the surface of the bone model is pointed by a pointer.

The following are the error factors that the imageless surgery support device has.

In the imageless surgery support device, a virtual bone 3D model is created and displayed on the monitor screen without using the CT DICOM data set, and the alignment is performed so as to correspond with the actual bone position. At the time of such alignment, it is difficult for the operator to accurately point the actual bone surface with the pointer according to the position indicating the registration displayed on the monitor screen of the surgical support device, and an error occurs.

In addition to the bone alignment method, there are the following error factors that the measurement method has.

According to the instructions displayed on the monitor screen of the surgical support device, the artificial joint (cup) and (stem) are placed on the bone. After that, imaging is performed by CT scan after surgery, and the DICOM data set of the CT is image-analyzed by image analysis software to obtain the installation position and installation angle of the artificial joint (cup) and (stem).

The installation position and installation angle of the artificial joint (cup) and (stem) on the operation support device screen are calculated based on the reference plane set for the 3D model of the bone at the time of preoperative planning. On the other hand, in postoperative image analysis, the installation position and installation angle of the artificial joint (cup) and (stem) are measured with respect to the new reference plane set for the bone CT imaged after surgery. It becomes. Since the reference planes of both of them do not completely match, an error occurs in the installation position and the installation angle.

The error described above can be easily verified by the verifier by providing the DICOM data set and the bone model verification tool according to the above embodiment.

All of the above-described embodiments are presented as examples, and are not intended to limit the technical scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments are included in the technical scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

For example, in the present embodiment, the accuracy verification tool is used for the accuracy verification of the surgical support device. However, it can be used not only for the surgical support device but also for the accuracy verification of the surgical cutting robot.

1 Reference for acetabular reamer,
3 Pelvic reference,
2, 4, 6, 8, 9 infrared reflective balls,
5 Reference for driving equipment,
7 Femur Reference 11A Patient's Pelvis,
11B 3D model pelvis,
11C pelvic model,
12 Upper right anterior iliac spine,
13 Upper left anterior iliac spine,
14 Right pubic tubercle,
15 Left pubic tubercle,
17A, 17B, 42, 43, 44 cylinders,
20 Surgical support device,
21 Monitor screen,
22 camera,
26 Greater trochanter trailing edge,
27 Left posterior condyle,
28 Right posterior condyle,
31 pointer,
32 acetabular reamer,
41A femur,
41B femur model,
45 Artificial joint (stem),
51 Driving equipment,
61 Left ischial nodule,
62 Right ischial nodule,
63 Central sacrum,
64 Pubic symphysis,
71 Trochanteric fossa,
72 The most distal end of the intercondylar region,
73 Greater trochanter end,
74 Left posterior condyle,
75 Right posterior condyle,

Claims (2)

Medical image data including information on the cross section of the bone, information for specifying the position and orientation of the reference plane in the bone, information indicating the installation position and installation angle of the artificial joint with respect to the reference plane, and the said A bone model containing the information indicating the installation position and the installation angle of the artificial joint, and
With
A preoperative plan is performed using the medical image data on the surgical support device to be verified for accuracy, and the installation position and angle of the artificial joint at the time of the preoperative plan and the bone model are regarded as a patient. An accuracy verification tool for a surgical support device, which comprises examining a difference between the installation position and the installation angle of the artificial joint during an operation. The information indicating the installation position and the installation angle of the artificial joint with respect to the reference plane is the medical image data and the cylinder provided in the bone model, and the position where the cylinder is provided is the position of the artificial joint. The accuracy verification tool for a surgical support device according to claim 1, wherein the installation position, the direction indicated by the longitudinal direction of the cylinder, is the installation angle of the artificial joint with respect to the reference plane.