Prosthesis installation calibration system and use method thereof

Abstract

The present invention discloses a prosthesis installation calibration system and a method for using the same, wherein the system comprises: an angle sensor, installed outside the surgical area of ​​the patient's affected part, for obtaining the inclination angle between the patient's affected part plane and the ground; an imaging device, for obtaining the patient's preoperative image; a C-arm machine, for obtaining the two-dimensional image of the front and side positions of the patient lying flat and the two-dimensional image of the front position of the actual prosthesis installation; a host computer, for registering the two-dimensional image of the front and side positions of the patient lying flat and the preoperative image, applying the registration result to the preoperative image of the doctor's planned installation of the prosthesis model, and obtaining the two-dimensional image of the front position of the ideal prosthesis installation; the host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation according to the two-dimensional images of the front position of the actual prosthesis installation and the ideal prosthesis installation, and performs calibration. The present invention can realize the calibration of the prosthesis installation, and thus can improve the accuracy of the prosthesis installation position.

Description

Technical Field

[0001] The present invention relates to the technical field of image processing, and in particular to a prosthesis installation calibration system and a use method thereof. Background Art

[0002] In orthopedic surgery, prostheses are often required to be installed, such as hip replacement surgery, which is increasingly widely used in clinical practice. During the operation, the installation accuracy of the prosthesis is required to be high, and generally, the more accurate the prosthesis is installed, the higher the success rate of the operation, and the lower the probability of subsequent sequelae and complications. Therefore, how to evaluate the accuracy of the prosthesis installation position and how to better adjust the prosthesis position to approach or even reach the optimal installation position are important indicators of surgical reliability.

[0003] During hip replacement surgery, we often judge the prosthesis installation position by taking 2D anteroposterior images before and after hip replacement; generally before hip replacement surgery, we will diagnose the patient's hip joint by taking CT or CBCT 3D images as an evaluation benchmark. However, after the operation, because the patient is in an anesthetized state, it is impossible for the patient to cooperate in taking standard anteroposterior 2D images. The doctor needs to take continuous trial shots to find the closest position to the anteroposterior position and compare it with the preoperative anteroposterior 2D image to determine whether the prosthesis placement meets the requirements, which prolongs the operation time, increases the difficulty of operation, and the doctor cannot make a quick judgment. Therefore, how to effectively use the 3D images of preoperative CT or CBCT to help evaluate or improve the accuracy of the prosthesis installation position has great clinical application value. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned deficiencies, the present invention provides a prosthesis installation calibration system and a method of using the same, which solves the problems in the prior art of being unable to efficiently adjust the C-arm machine to capture the frontal and lateral two-dimensional images after the replacement prosthesis, and being unable to effectively determine the accuracy of the prosthesis installation position and improve the prosthesis installation accuracy, thereby ensuring the stability and reliability of the prosthesis installation accuracy.

[0005] Technical solution: The present invention provides a prosthesis installation and calibration system, comprising:

[0006] An angle sensor is installed outside the surgical area of ​​the patient's affected part to obtain the inclination angle between the patient's affected part and the ground;

[0007] Imaging equipment, used to obtain preoperative images of patients;

[0008] C-arm machine, used to obtain the anteroposterior and lateral two-dimensional images of the patient lying flat and the anteroposterior two-dimensional images of the actual prosthesis installation;

[0009] The host computer is used to register the two-dimensional images of the patient lying flat with the preoperative images, and apply the registration results to the preoperative images of the prosthesis model planned by the doctor to obtain the two-dimensional anteroposterior image of the ideal prosthesis installation;

[0010] The host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation based on the two-dimensional positive images of the actual prosthesis installation and the ideal prosthesis installation, and determines whether the deviation angle is less than a set threshold. If so, the prosthesis installation meets the requirements; otherwise, the installation position of the prosthesis is adjusted until the deviation angle is less than the set threshold.

[0011] Specifically, the registration of the two-dimensional images of the patient in the supine position and the preoperative images is performed as follows:

[0012] The host computer starts with a set initial projection direction for the preoperative image, rotates around the upper and lower axes of the anatomical coordinate system with a set angle step, and forward projects the preoperative image after each rotation to obtain several groups of corresponding anteroposterior and lateral two-dimensional images, calculates the similarity between each group of anteroposterior and lateral two-dimensional images and the anteroposterior and lateral two-dimensional images when the patient is lying flat, obtains the rotation angle around the upper and lower axes of the anatomical coordinate system corresponding to the group of anteroposterior and lateral two-dimensional images corresponding to the maximum similarity, which is the required flip angle, and completes the alignment.

[0013] More specifically, the setting angle step is between 0.1° and 2°.

[0014] More specifically, the similarity between the two-dimensional images adopts mutual information entropy.

[0015] Specifically, when the prosthesis is installed, the C-arm machine adjusts its sliding angle according to the inclination angle between the patient's affected part plane and the ground obtained by the angle sensor, and obtains the corresponding two-dimensional anteroposterior image after the adjustment to obtain the two-dimensional anteroposterior image of the actual prosthesis installation.

[0016] Specifically, the host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation, specifically:

[0017] The diameter of the bottom surface of the acetabular cup is obtained according to the size of the installed prosthesis model;

[0018] Get respectively:

[0019] The pixel size of the diameter of the bottom surface of the acetabular cup and the pixel size of the distance from the bottom surface of the acetabular cup to the top of its top surface in the anteroposterior two-dimensional images of the ideal prosthesis installation and the actual prosthesis installation;

[0020] The pixel size of the distance from the bottom surface of the acetabular cup to the top of its top surface is converted into a physical size, and the deviation between the physical size corresponding to the ideal prosthesis installation and the actual prosthesis installation is calculated based on this. Combined with the diameter of the bottom surface of the acetabular cup in the prosthesis model, the deviation angle between the actual prosthesis installation and the ideal prosthesis installation is calculated.

[0021] Specifically, the set threshold is set to 5°.

[0022] The present invention also provides a method for using the above-mentioned prosthesis installation calibration system, comprising the steps of:

[0023] S1. An angle sensor for collecting the inclination angle between the plane of the patient's affected part and the ground is installed on the patient, and the imaging device obtains the patient's preoperative image. The doctor plans the installation position of the prosthesis model based on the preoperative image;

[0024] S2, using a C-arm machine to collect the anteroposterior and lateral two-dimensional images of the patient lying flat, and the host computer aligns the anteroposterior and lateral two-dimensional images of the patient lying flat with the preoperative images, and applies the alignment results to the preoperative images of the prosthesis model planned by the doctor to obtain the anteroposterior two-dimensional images of the ideal prosthesis installation;

[0025] S3, obtaining the inclination angle between the plane of the patient's affected part and the ground after the prosthesis is installed through the angle sensor, and adjusting its sliding angle accordingly, and obtaining the corresponding anteroposterior two-dimensional image after the adjustment, so as to obtain the anteroposterior two-dimensional image of the actual prosthesis installation;

[0026] S4: The host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation in combination with S3 and S2, and determines whether it is less than the set threshold. If so, the prosthesis installation meets the requirements and the installation is completed; otherwise, the installation position of the prosthesis is adjusted and the process returns to S3.

[0027] Beneficial effects: The present invention can compare the actual two-dimensional anteroposterior image of the prosthesis installation with the two-dimensional anteroposterior image of the prosthesis model installed under ideal conditions to determine whether the prosthesis is installed or adjusted in place, and make adjustments if it is not in place, thereby achieving calibration of the prosthesis installation, and further improving the accuracy of the prosthesis installation position. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are merely embodiments of the present invention, and ordinary technicians in this field can obtain other drawings based on these drawings without creative work.

[0029] Figure 1 This is an example of a two-dimensional image of the hip bone taken by a C-arm machine while the patient is lying flat;

[0030] Figure 2 This is an example of a lateral two-dimensional image of the hip bone of a patient lying flat, taken by a C-arm machine;

[0031] Figure 3 is an example diagram of measuring the pixel size of the diameter of the bottom surface of the acetabular cup in the two-dimensional anteroposterior image, in which d represents the pixel size of the diameter of the bottom surface of the acetabular cup;

[0032] Figure 4 is a measurement example diagram of the pixel size of the distance between the bottom surface of the acetabular cup and the top of its top surface in the two-dimensional anteroposterior image. In the diagram, L represents the pixel size of the distance between the bottom surface of the acetabular cup and the top of its top surface.

[0033] Figure 5 A flow chart of a method for using the prosthesis installation calibration system of the present invention;

[0034] Figure 6 The present invention is a flow chart for calculating the deviation angle between the actual prosthesis installation and the prosthesis model installation under ideal conditions. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0036] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the common meanings understood by people with ordinary skills in the field to which the present invention belongs. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects.

[0037] The prosthesis installation and calibration system provided by the present invention comprises:

[0038] The angle sensor is installed outside the surgical area of ​​the patient's affected part (such as outside the hip joint in hip replacement surgery) and is used to obtain the inclination angle between the plane of the patient's affected part and the ground. When the patient lies flat, the angle value of the angle sensor is corrected to 0 degrees. When the patient turns over, the angle value of the angle sensor and the direction of the patient's turning (such as turning left or right) must be recorded at the same time. In a specific embodiment of the present invention, the patient's affected part is the patient's hip joint.

[0039] In a specific embodiment of the present invention, the angle sensor generally includes three components, two of which are installed on the anterior superior iliac spines on both sides of the patient, and the other is placed on the ground as a reference point, and the inclination angle between the patient's hip joint plane and the ground is obtained based on the principle of determining a plane with three points. The specific structure can be referred to the relevant records in the published patent CN111616845A, which will not be repeated here.

[0040] The imaging device is used to obtain the patient's preoperative image; in the present invention, the patient's preoperative image can be a CT image or a CBCT image.

[0041] The C-arm machine is used to obtain the two-dimensional anteroposterior and lateral images of the patient when lying flat and the two-dimensional anteroposterior image of the actual prosthesis installation; wherein the C-arm machine obtains the inclination angle between the plane of the patient's affected part and the ground when the prosthesis is installed based on the angle sensor, adjusts its sliding angle, and obtains the corresponding two-dimensional anteroposterior image after the adjustment, that is, obtains the two-dimensional anteroposterior image of the actual prosthesis installation.

[0042] The C-arm machine adjusts its sliding angle according to the patient's flip angle, and obtains the patient's two-dimensional anteroposterior and lateral images after the adjustment; when the patient lies flat, the patient's flip angle can be determined to be 0, and the C-arm machine obtains the patient's two-dimensional anteroposterior and lateral images at this time; after the patient flips, the angle sensor installed on the patient is used to obtain the patient's rotation angle around the upper and lower axes of the anatomical coordinate system after the flip, and the C-arm machine adjusts its sliding angle accordingly, and then obtains the patient's two-dimensional anteroposterior and lateral images.

[0043] The host computer is used to register the two-dimensional anteroposterior and lateral images of the patient lying flat with the preoperative images, and apply the registration results to the preoperative images of the prosthesis model planned by the doctor to obtain the two-dimensional anteroposterior image of the prosthesis model installed under ideal conditions, that is, the two-dimensional anteroposterior image of the ideal prosthesis installation;

[0044] In the present invention, the host computer registers the two-dimensional images of the patient lying flat on the front and side with the preoperative images, as follows:

[0045] The host computer starts with the set initial projection direction for the preoperative image, rotates around the upper and lower axes of the anatomical coordinate system with the set angle step, and forward projects the preoperative image after each rotation to obtain several groups of corresponding anteroposterior and lateral two-dimensional images, calculates the similarity between each group of anteroposterior and lateral two-dimensional images and the anteroposterior and lateral two-dimensional images of the patient lying flat collected by the C-arm machine, obtains the rotation angle around the upper and lower axes of the anatomical coordinate system corresponding to the group of anteroposterior and lateral two-dimensional images corresponding to the maximum similarity, and then obtains the flip angle of the anteroposterior and lateral two-dimensional images of the patient lying flat relative to the preoperative image. Among them, the set angle step can be between 0.1° and 2°.

[0046] In the present invention, the similarity between two-dimensional images can adopt mutual information entropy.

[0047] The host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation according to the two-dimensional anteroposterior image of the actual prosthesis installation and the two-dimensional anteroposterior image of the ideal prosthesis installation, and determines whether it is less than the set threshold value. If it is less than, it is considered that the prosthesis installation meets the requirements and the installation is completed; otherwise, it is considered that the prosthesis installation does not meet the requirements and the installation position of the prosthesis needs to be adjusted until the deviation angle between the actual prosthesis installation and the ideal prosthesis installation is less than the set threshold value. In the present invention, the set threshold value can be set to 5°.

[0048] In the present invention, the deviation angle between the actual prosthesis installation and the ideal prosthesis installation is calculated, specifically:

[0049] The diameter of the bottom surface of the acetabular cup is obtained according to the size of the installed prosthesis model;

[0050] Get respectively:

[0051] The pixel size of the diameter of the bottom surface of the acetabular cup and the pixel size of the distance from the bottom surface of the acetabular cup to the top of its top surface in the anteroposterior two-dimensional image of the ideal prosthesis installation;

[0052] The pixel size of the diameter of the bottom surface of the acetabular cup and the pixel size of the distance from the bottom surface of the acetabular cup to the top of its top surface in the two-dimensional anteroposterior image of the actual prosthesis installation;

[0053] The pixel size of the distance from the bottom surface of the acetabular cup to the top of its top surface is converted into a physical size, and the deviation between the physical size corresponding to the ideal prosthesis installation and the actual prosthesis installation is calculated based on this. The deviation angle between the actual prosthesis installation and the ideal prosthesis installation can then be calculated in combination with the diameter of the bottom surface of the acetabular cup in the prosthesis model.

[0054] The present invention obtains the patient's flip angle when installing or adjusting the prosthesis through an angle sensor, and controls the C-arm machine to adjust its sliding angle accordingly to obtain the corresponding patient's two-dimensional frontal image, compare it with the two-dimensional frontal image of the ideal prosthesis installation, calculate the deviation angle between the actual prosthesis installation and the ideal prosthesis installation, so as to judge whether the prosthesis is installed in place, and adjust it when it is not in place, thereby realizing the calibration of the prosthesis installation, and further improving the accuracy of the prosthesis installation position, solving the problems in the prior art such as hip replacement surgery, that the C-arm machine cannot be efficiently adjusted to take the two-dimensional frontal and lateral images of the replaced prosthesis, and cannot effectively judge the prosthesis installation position accuracy and improve the prosthesis installation accuracy, thereby ensuring the stability and reliability of the prosthesis installation accuracy.

[0055] The present invention also provides a method for using the prosthesis installation calibration system as described above. Figure 5 As shown, the steps include:

[0056] S1. An angle sensor for collecting the inclination angle between the plane of the patient's affected part and the ground is installed on the patient, and the imaging device obtains the patient's preoperative image. The doctor plans the installation position of the prosthesis model based on the preoperative image;

[0057] The doctor plans the prosthesis model to be installed in the preoperative image according to its size. During this process, the doctor can adjust the position of the prosthesis model in the preoperative image multiple times, and can confirm the installation position of the prosthesis model from multiple angles. Therefore, the doctor can obtain the ideal installation effect of the prosthesis model in the preoperative image by planning the prosthesis model on the preoperative image. In the subsequent process, the doctor's planning of the prosthesis model on the preoperative image can serve as a reference indicator for the installation of the prosthesis model during surgery. In a specific embodiment of the present invention, in hip replacement, the prosthesis is generally a hemispherical structure. When the prosthesis is ideally installed, its bottom surface is displayed as a straight line in the two-dimensional anteroposterior image, and its top surface is displayed as an arc surface.

[0058] In the present invention, the doctor plans the prosthesis model to the preoperative image through existing software on the market, such as Changmugu's three-dimensional preoperative planning software based on CT data, Aikon's customized surgical planning platform, and the like.

[0059] S2, using a C-arm machine to collect the anteroposterior and lateral two-dimensional images of the patient lying flat, and the host computer aligns the anteroposterior and lateral two-dimensional images of the patient lying flat with the preoperative images, and applies the alignment results to the preoperative images of the prosthesis model planned by the doctor to obtain the anteroposterior two-dimensional images of the ideal prosthesis installation;

[0060] When the patient lies flat, the plane of the patient's affected part is parallel to the ground. At this time, the angle sensor is 0°. The C-arm is moved near the patient and the C-arm is aimed at the patient's affected part by means of the laser indication of the C-arm. In this embodiment, the patient's affected part is the patient's hip joint.

[0061] Specifically, the sliding angle of the C-arm machine is adjusted. When the sliding angle of the C-arm machine is 0°, an anteroposterior two-dimensional image of the patient lying flat is acquired; when the sliding angle of the C-arm machine is 90° or -90°, a lateral two-dimensional image of the patient lying flat is acquired. In this embodiment, the anteroposterior and lateral two-dimensional images of the patient obtained in this step are images of the patient before hip replacement.

[0062] In the present invention, the host computer calculates the flip angle of the two-dimensional anteroposterior and lateral images of the patient lying flat captured by the C-arm machine relative to the preoperative image obtained by S1 based on the alignment results, and applies the flip angle to the preoperative image after the prosthesis model is installed according to the plan of S1, so as to obtain the two-dimensional anteroposterior image of the prosthesis model installed under ideal conditions, that is, the two-dimensional anteroposterior image of the ideal prosthesis installation.

[0063] Specifically:

[0064] S21, the host computer rotates the preoperative image obtained in S1 around the upper and lower axes of the anatomical coordinate system with a set angle step length starting from the set initial projection direction, and forward projects the preoperative image after each rotation to obtain several sets of mutually corresponding two-dimensional images in the frontal and lateral positions;

[0065] Specifically, the coordinates of the preoperative image obtained by S1 in the anatomical coordinate system are forward projected, and the initial projection direction is along the AP direction of the anatomical coordinate system (i.e., the anterior-posterior axis direction of the anatomical coordinate system). At this time, the rotation angle around the upper and lower axes of the anatomical coordinate system is 0°, and the patient can rotate clockwise around the upper and lower axes of the anatomical coordinate system (i.e., the SI axis). Each rotation angle increases by a set angle step, and forward projection is performed after each rotation to obtain several groups of corresponding anteroposterior two-dimensional images and lateral two-dimensional images, and each group of corresponding rotation angles around the SI axis can be recorded.

[0066] Among them, the calculation formula for generating the frontal or lateral two-dimensional image by forward projection is:

[0067] ;

[0068] in, x and y is the row and column coordinates of the generated two-dimensional image, I ( x , y ) is the pixel value of the generated two-dimensional image, I 0 is the maximum pixel value of a point in the preoperative image; ( i , j , k ) is the coordinate of a point in the preoperative image, proj ( i , j , k ) is the point in the preoperative image ( i , j , k ), f ( i , j , k ) is the point in the preoperative image ( i , j , k ) and the points in the generated two-dimensional image ( x , y ) and all intersection points of the straight line between them and the preoperative image;

[0069] In the present invention, according to different requirements for the rotation angle accuracy deviation, the angle step size can be set to be between 0.1° and 2°. In this embodiment, the angle step size is set to be 0.2°.

[0070] S22, the host computer respectively calculates the similarity between each group of anteroposterior and lateral two-dimensional images obtained in S21 and the anteroposterior and lateral two-dimensional images of the patient lying flat collected by the C-arm machine, obtains the rotation angle corresponding to the group of anteroposterior and lateral two-dimensional images corresponding to the maximum similarity, and then obtains the flip angle of the anteroposterior and lateral two-dimensional images of the patient lying flat relative to the preoperative image;

[0071] In the present invention, the mutual information entropy can be used to calculate the similarity between each group of anteroposterior and lateral two-dimensional images obtained in S21 and the anteroposterior and lateral two-dimensional images of the patient lying flat collected by the C-arm machine. The mutual information entropy of the two images is calculated as follows:

[0072] ;

[0073] ;

[0074] ;

[0075] In this embodiment, the mutual information entropy calculation between the frontal two-dimensional images is taken as an example, and the mutual information entropy calculation between the lateral two-dimensional images is consistent with that of the frontal two-dimensional images; A represents each group of positive two-dimensional images obtained by forward projection of S21, H ( A ) represents an image A The entropy of B It represents the two-dimensional image of the patient lying flat on his back acquired by the C-arm. H ( B ) represents an image B The entropy of H ( A ) are consistent; H ( A , B ) represents an image A With image B The cross entropy of N It represents the grayscale level of the grayscale histogram in each group of positive two-dimensional images obtained by forward projection of S21, which can usually be 256, 1000, etc.; p i Indicates the gray value is i The probability of a point appearing in the image; p AB ( a , b ) indicates that the pixels at the same position in the image A The gray value is a , in the image B The gray value is b The probability of MI ( A , B ) represents the image at a certain rotation angleA With image B The mutual information entropy of

[0076] Then we can get:

[0077] P θ = MI ( A , B ) max ;

[0078] in, MI ( A , B ) max Represents images at all rotation angles A With image B The maximum value of the mutual information entropy is P θ Representing images A and images B The maximum similarity of θ Indicates the rotation angle corresponding to a set of frontal and lateral two-dimensional images when the similarity is maximum.

[0079] In addition, the present invention can comprehensively consider the similarity of the anteroposterior two-dimensional image and the similarity of the lateral two-dimensional image, and can improve the robustness and accuracy of the registration. For example, in the case of each rotation angle, the similarity of the anteroposterior two-dimensional image and the similarity of the lateral two-dimensional image corresponding to the rotation angle can be summed or averaged, and the maximum value can be found, and the corresponding rotation angle at this time is used as the required flip angle.

[0080] S3, obtaining the inclination angle between the plane of the patient's affected part and the ground after the prosthesis is installed or adjusted through the angle sensor, the C-arm machine adjusts its sliding angle according to the inclination angle, and obtains the corresponding anteroposterior two-dimensional image, that is, the anteroposterior two-dimensional image of the actual prosthesis installation;

[0081] When installing a prosthesis or adjusting its position, the patient will flip over. The angle sensor can be used to obtain the inclination angle between the patient's affected area and the ground after the patient flips over, that is, the patient's rotation angle relative to the upper and lower axes of the anatomical coordinate system. The sliding angle of the C-arm machine is adjusted according to this inclination angle, and a two-dimensional image of the patient's frontal position is obtained after the adjustment.

[0082] S4, the host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation according to the two-dimensional anteroposterior image of the actual prosthesis installation obtained in S3 and the two-dimensional anteroposterior image of the ideal prosthesis installation obtained in S2, and determines whether the deviation angle is less than the set threshold. If so, it is considered that the prosthesis installation meets the requirements and the installation is completed; otherwise, it is considered that the prosthesis installation does not meet the requirements and the installation position of the prosthesis needs to be adjusted, and the process returns to S3;

[0083] Specifically, the deviation angle between the actual prosthesis installation and the ideal prosthesis installation is calculated as follows: Figure 6 As shown, the details are as follows:

[0084] S41. According to the size of the installed prosthesis model, the diameter of the bottom surface of the acetabular cup is D 0mm;

[0085] S42, obtaining the pixel size of the diameter of the bottom surface of the acetabular cup in the anteroposterior two-dimensional image of the ideal prosthesis installation obtained in S2 d 1 and the distance from the bottom of the acetabular cup to the top of its top surface in pixels L 1. Example Figure 2 , 3 As shown;

[0086] S43, obtaining the pixel size of the diameter of the bottom surface of the acetabular cup in the two-dimensional anteroposterior image of the actual prosthesis installation obtained in S3 d 2 and the pixel size of the distance from the bottom of the acetabular cup to the top of its top surface L 2;

[0087] S43, respectively converting the pixel sizes of the corresponding distances obtained in S42 and S43 into physical sizes, and calculating the absolute value Δ of the difference between the two L :

[0088] ;

[0089] S44, the absolute value Δ of the difference between the two obtained according to S43 L and the diameter of the bottom surface of the acetabular cup obtained by S41, and the deviation angle Δ between the actual prosthesis installation and the ideal prosthesis installation is calculated θ :

[0090] .

[0091] The present invention can calculate the deviation angle between the actual prosthesis installation and the ideal prosthesis installation to determine whether the prosthesis is installed in place, and make adjustments if it is not in place, thereby achieving calibration of the prosthesis installation, and further improving the accuracy of the prosthesis installation position.

[0092] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; the embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the scope of protection of the present invention.

Claims

1. A prosthesis installation and calibration system, characterized in that: include: An angle sensor is installed outside the surgical area of ​​the patient's affected part to obtain the inclination angle between the patient's affected part and the ground; Imaging equipment, used to obtain preoperative images of patients; The C-arm machine is used to obtain the two-dimensional images of the patient's front and side positions when the patient is lying flat. At the same time, the angle sensor is used to obtain the inclination angle between the patient's affected part plane and the ground when the prosthesis is installed, and the sliding angle is adjusted. After the adjustment, the corresponding two-dimensional frontal image is obtained, that is, the two-dimensional frontal image of the actual prosthesis installation is obtained; The host computer is used to register the two-dimensional images of the patient lying flat with the preoperative images, obtain a flip angle according to the registration, and apply the flip angle to the preoperative image of the prosthesis model planned by the doctor to obtain an ideal two-dimensional image of the prosthesis installation; The host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation based on the two-dimensional positive images of the actual prosthesis installation and the ideal prosthesis installation, and determines whether the deviation angle is less than a set threshold. If so, the prosthesis installation meets the requirements; otherwise, the installation position of the prosthesis is adjusted until the deviation angle is less than the set threshold.

2. The prosthesis installation and calibration system according to claim 1, characterized in that: The host computer registers the two-dimensional images of the patient lying flat on the front and side with the preoperative images, specifically: The host computer starts with a set initial projection direction for the preoperative image, rotates around the upper and lower axes of the anatomical coordinate system with a set angle step, and forward projects the preoperative image after each rotation to obtain several groups of corresponding anteroposterior and lateral two-dimensional images, calculates the similarity between each group of anteroposterior and lateral two-dimensional images and the anteroposterior and lateral two-dimensional images when the patient is lying flat, and obtains the rotation angle around the upper and lower axes of the anatomical coordinate system corresponding to the group of anteroposterior and lateral two-dimensional images corresponding to the maximum similarity, which is the required flip angle.

3. The prosthesis installation and calibration system according to claim 2, characterized in that: The setting angle step is between 0.1° and 2°.

4. The prosthesis installation and calibration system according to claim 2, characterized in that: The similarity between the two-dimensional images adopts mutual information entropy.

5. The prosthesis installation and calibration system according to claim 1, characterized in that: The host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation, specifically: The diameter of the bottom surface of the acetabular cup is obtained according to the size of the installed prosthesis model; Get respectively: The pixel size of the diameter of the bottom surface of the acetabular cup and the pixel size of the distance from the bottom surface of the acetabular cup to the top of its top surface in the anteroposterior two-dimensional images of the ideal prosthesis installation and the actual prosthesis installation; The pixel size of the distance from the bottom surface of the acetabular cup to the top of its top surface is converted into a physical size, and the deviation between the physical size corresponding to the ideal prosthesis installation and the actual prosthesis installation is calculated based on this. Combined with the diameter of the bottom surface of the acetabular cup in the prosthesis model, the deviation angle between the actual prosthesis installation and the ideal prosthesis installation is calculated.

6. The prosthesis installation and calibration system according to claim 1, characterized in that: The set threshold is set to 5°.

7. A method for using the prosthesis installation and calibration system according to any one of claims 1 to 6, characterized in that: Includes steps: S1. An angle sensor for collecting the inclination angle between the plane of the patient's affected part and the ground is installed on the patient, and the imaging device obtains the patient's preoperative image. The doctor plans the installation position of the prosthesis model based on the preoperative image; S2, using a C-arm machine to collect the anteroposterior and lateral two-dimensional images of the patient lying flat, and the host computer aligns the anteroposterior and lateral two-dimensional images of the patient lying flat with the preoperative images, and applies the alignment results to the preoperative images of the prosthesis model planned by the doctor to obtain the anteroposterior two-dimensional images of the ideal prosthesis installation; S3, obtaining the inclination angle between the plane of the patient's affected part and the ground after the prosthesis is installed through the angle sensor, and adjusting its sliding angle accordingly, and obtaining the corresponding anteroposterior two-dimensional image after the adjustment, so as to obtain the anteroposterior two-dimensional image of the actual prosthesis installation; S4: The host computer calculates the deviation angle between the actual prosthesis installation and the ideal prosthesis installation in combination with S3 and S2, and determines whether it is less than the set threshold. If so, the prosthesis installation meets the requirements and the installation is completed; otherwise, the installation position of the prosthesis is adjusted and the process returns to S3.

Images