CN113408151B - Navigation method and system for assisting acetabular cup implantation through acetabular collapse reconstruction technology - Google Patents

Navigation method and system for assisting acetabular cup implantation through acetabular collapse reconstruction technology Download PDF

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CN113408151B
CN113408151B CN202110809496.7A CN202110809496A CN113408151B CN 113408151 B CN113408151 B CN 113408151B CN 202110809496 A CN202110809496 A CN 202110809496A CN 113408151 B CN113408151 B CN 113408151B
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acetabulum
acetabular
acetabular cup
model
cup
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CN113408151A (en
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杨一婧
沈珺
何燕
郭靖
蔡述庭
熊晓明
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Guangdong University of Technology
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/10—Computer-aided planning, simulation or modelling of surgical operations
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/20—Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T17/00—Three dimensional [3D] modelling, e.g. data description of 3D objects
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T19/00—Manipulating 3D models or images for computer graphics
    • G06T19/003—Navigation within 3D models or images
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/10—Segmentation; Edge detection
    • G06T7/11—Region-based segmentation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/10—Computer-aided planning, simulation or modelling of surgical operations
    • A61B2034/101—Computer-aided simulation of surgical operations
    • A61B2034/105—Modelling of the patient, e.g. for ligaments or bones
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/10—Computer-aided planning, simulation or modelling of surgical operations
    • A61B2034/107—Visualisation of planned trajectories or target regions
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/10—Computer-aided planning, simulation or modelling of surgical operations
    • A61B2034/108—Computer aided selection or customisation of medical implants or cutting guides
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/20—Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
    • A61B2034/2046—Tracking techniques
    • A61B2034/2065—Tracking using image or pattern recognition
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
    • G—PHYSICS
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    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
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    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
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    • G06T2207/30—Subject of image; Context of image processing
    • G06T2207/30004—Biomedical image processing
    • G06T2207/30008—Bone

Abstract

In order to solve the defects of the prior art, the invention provides a navigation method and a navigation system for assisting acetabular cup implantation by an acetabular collapse reconstruction technology, wherein the navigation method comprises the following steps: segmenting a CT/MRI image of an acetabulum part and then modeling the acetabulum part to obtain an acetabulum model; positioning the surgical position of the acetabular cup, and obtaining the depth of the acetabular cup and the number of contact points of the acetabular cup and the acetabular model by utilizing the acetabular cup to make initial contact with the acetabular model; determining a portion of the acetabulum of the patient to be bruised in the acetabulum part according to the depth of the acetabulum cup and the number of contact points of the acetabulum cup and the acetabulum model; constructing a mathematical expression of a frustration tool, and determining a frustration tool model; and carrying out simulation navigation on the assigned contusion tool model, and analyzing the effect of the milled acetabulum part. The method can carry out surgical planning and modeling on the seriously worn acetabulum according to the shape of the acetabulum cup, thereby achieving the effect of surgical planning.

Description

Navigation method and system for assisting acetabular cup implantation through acetabular collapse reconstruction technology
Technical Field
The invention relates to the technical field of joint reconstruction, in particular to a navigation method, a navigation system, an electronic device and a computer-readable storage medium for assisting acetabular cup implantation by an acetabular collapse reconstruction technology.
Background
Total hip replacement, an operation in which an originally damaged hip joint is replaced with an artificial acetabulum and an artificial femoral head, has proven to be an effective method for treating end-stage hip joint diseases.
The main challenge of such surgery is how to implant the acetabular cup in the correct position and angle to the hip of the patient. Good long-term results in total hip replacement depend on precise positioning techniques and accurate acetabular cup implantation angles, which are critical to avoid loosening and dislocation of the prosthetic joint. In conventional total hip replacement surgery, the surgeon performs the positioning of the acetabular cup as guided by the patient's preoperative CT/MRI images. Due to the complexity and time involved in the surgical procedure, such procedures can increase the intraoperative fatigue of the surgeon, thereby affecting the accuracy of the procedure. In addition, when the body position of the patient is seriously changed, the preoperative positioning accuracy is confirmed by X-ray reexamination, so that a great amount of radiation is caused to doctors and the patient, the operation time is prolonged, and the pain of the patient is increased; the second challenge of surgery is how to solve the problem of misalignment of the acetabulum with the acetabular cup. In the actual operation, the acetabulum of the patient has serious abrasion. In the real operation process, in order to accurately place the acetabular cup and avoid gradual deviation from the center of the acetabulum in the process of grinding and contusion caused by shallow acetabulum of a patient, the acetabulum is generally deepened by using a small-size acetabular grinding contusion, and then the large-size acetabular grinding contusion is replaced by using the small-size acetabular grinding contusion as the center for grinding.
However, in the conventional surgery, when the acetabulum is seriously collapsed, a doctor cannot accurately implement the preoperative planning scheme into a real surgical scene, and the ideal planning path and depth are easily deviated in the grinding process, so that great obstruction effects are caused on the acetabulum cup placement and postoperative repair after the surgery.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a navigation method for assisting the acetabular cup implantation by using an acetabular collapse reconstruction technology, which is used for solving at least one technical problem in the background art.
The technical scheme adopted by the invention is as follows:
a navigation method for acetabular collapse reconstruction technology assisted acetabular cup implantation comprises the following steps:
segmenting a CT/MRI image of an acetabulum part and then modeling the acetabulum part to obtain an acetabulum model;
positioning the surgical position of the acetabular cup, and obtaining the depth of the acetabular cup and the number of contact points of the acetabular cup and the acetabular model by utilizing the acetabular cup to make initial contact with the acetabular model;
determining the portion of the acetabulum part of the patient to be bruised according to the depth of the acetabulum cup and the number of contact points of the acetabulum cup and the acetabulum model;
constructing a mathematical expression of a frustration tool, and determining a frustration tool model;
assigning the grinding tool model and the acetabulum model to obtain an assigned grinding tool model and an assigned acetabulum model;
and carrying out simulation navigation on the assigned acetabulum model by using the assigned frustration tool model, and analyzing the frustrated effect of the acetabulum part.
The step of modeling the acetabulum part after segmenting the CT/MRI image of the acetabulum part comprises the following steps:
obtaining CT/MRI data of a pelvic model of a patient;
automatically segmenting the CT/MRI data to obtain segmented CT/MRI images;
and carrying out three-dimensional modeling on the segmented CT/MRI image.
Prior to "positioning the surgical position of the acetabular cup", comprising:
modeling the acetabular cup using the following equation:
Figure BDA0003164237890000031
and obtaining the bending degree of the surface of the acetabular cup according to the mathematical expression of the average curvature G and the Gaussian curvature K and the ellipsoidal parameter:
Figure BDA0003164237890000032
Figure BDA0003164237890000033
wherein R = R + l, H = H + l; the radius of the inner circle of the cup opening of the acetabular cup is r, the thickness of the acetabular cup is l, and the height from the lowest point of the inner surface of the acetabular cup to the cup opening is h; theta represents the angle formed by the connecting line of the point of the calculated curvature and the central point of the cup opening and the cup opening.
Positioning the surgical position of the acetabular cup, and obtaining the depth of the acetabular cup and the number of contact points of the acetabular cup and the acetabular model by using the acetabular cup and the acetabular model for initial contact, comprising:
setting an auxiliary horizontal line at the end of the acetabulum of a patient, and obtaining an entry point position of the acetabular cup according to the auxiliary horizontal line;
making initial contact of the acetabular cup with the patient's acetabulum at the entry point location;
obtaining the number of contact points of the acetabular cup and the acetabulum of the patient according to the depth of the acetabular cup approaching the acetabulum of the patient into the patient;
the step of determining the part to be bruised of the acetabulum part of the patient according to the depth of the acetabulum cup and the number of contact points of the acetabulum cup and the acetabulum model comprises the following steps:
obtaining a maximum number of contact points for the acetabular cup to be in full contact at the patient's acetabulum;
contacting the acetabular cup with the acetabulum of the patient at the entry point position, and acquiring the number of first contact points of the acetabular cup and the acetabulum of the patient at the maximum depth;
and when the number of the first contact points is less than the maximum number of the contact points, recording corresponding contact positions and determining the contact positions as parts to be subjected to frustration.
The "obtaining the number of contact points of the acetabular cup and the acetabulum of the patient according to the depth of the acetabular cup approaching the acetabulum of the patient to the acetabulum of the patient" comprises:
obtaining the number W of contact points of the acetabular cup and the acetabulum of the patient by the following formula:
Figure BDA0003164237890000041
where σ is the variance of the contact points within the measurement depth range,
Figure BDA0003164237890000042
the mean of the contact points within the measurement depth range; b is the depth of the acetabular cup approaching the patient's body at the patient's acetabulum.
The 'constructing a mathematical expression of a frustration tool and determining a frustration tool model' includes:
the mathematical formula of the filing tool is as follows:
Figure BDA0003164237890000043
wherein R = R + l, H = H + l; the radius of the inner circle of the cup opening of the acetabular cup is r, the thickness of the acetabular cup is l, and the height from the lowest point of the inner surface of the acetabular cup to the cup opening is h; alpha is more than 2 and less than 3; beta is more than 2 and less than 3.
The steps of performing simulation navigation on the assigned acetabulum model by using the frustration tool model after assignment and analyzing the frustrated effect of the acetabulum part comprise:
carrying out a simulation process of elasticity limit and strength limit on the acetabulum; and/or the presence of a gas in the gas,
obtaining the grinding time per unit volume; and/or the presence of a gas in the atmosphere,
determining a magnitude of the applied force, a direction of the applied force, and a time of the applied force while filing the acetabulum.
A navigation system for assisting acetabular cup implantation by acetabular collapse reconstruction technology comprises:
the image segmentation module is connected with an external image acquisition device and is used for segmenting the acquired CT/MRI image of the acetabulum part;
the processing unit is connected with the graph segmentation module and is used for modeling the acetabulum part according to the segmented image to obtain an acetabulum model;
the storage module is connected with the processing unit and is used for storing an acetabular cup model and a bruise tool model;
the processing unit is communicated with the storage module and is used for calling the acetabular cup model and the acetabular model and determining a part to be bruised in the acetabular model after the acetabular cup model and the acetabular model are initially contacted;
the processing unit is communicated with the storage module and is used for calling a bruise tool model and the acetabular cup model to carry out bruise simulation.
An electronic device for acetabular collapse reconstruction technology assisted acetabular cup implantation, comprising:
a storage medium for storing a computer program;
and the processing unit is used for exchanging data with the storage medium and executing the computer program through the processing unit when the acetabulum collapse reconstruction technology-assisted acetabulum cup implantation is carried out so as to carry out the steps of the acetabulum collapse reconstruction technology-assisted acetabulum cup implantation method.
A computer-readable storage medium in which:
the computer readable storage medium having stored therein a computer program;
the computer program, when executed, performs the steps of the acetabular collapse reconstruction technique-assisted acetabular cup implantation method described above.
The invention has the beneficial effects that:
according to the method, an acetabulum model is obtained by segmenting a CT/MRI image of an acetabulum part and then modeling the acetabulum part; then, positioning the surgical position of the acetabular cup to obtain positioning data of the acetabular cup, including: the depth of the acetabular cup and the number of contact points of the acetabular cup with the acetabular model; determining a part to be bruised of the acetabulum part of the patient according to the acetabulum cup model and the positioning data of the acetabulum cup; constructing a mathematical expression of the bruise tool, and determining the model of the bruise tool; finally, carrying out simulation navigation on the milled tool model after the value assignment, and analyzing the milled effect of the acetabulum part; the method can plan and model the severely worn acetabulum according to the shape of the acetabulum cup, and determine the force required to be applied in the operation through the simulation of the grinding and rubbing step in the operation, thereby achieving the effect of operation planning; and the data obtained by simulation can be transmitted to a mechanical device with 6 degrees of freedom for automatic rubbing, so that an ideal preoperative planning effect is achieved.
According to the system, data exchange is carried out between the processing unit and the storage module, the acetabular cup model is in contact with the acetabular cup model, the part to be milled is determined, and then milling simulation is carried out by calling a milling tool model in the storage module, so that the purpose of navigation for implanting the acetabular cup is achieved.
Drawings
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a point cloud format of the acetabulum in a normal state.
FIG. 3 is a graphical representation of a point cloud of areas where the acetabulum is collapsed.
Figure 4 is a view of the acetabular cup configuration.
Fig. 5 is a cross-sectional view of fig. 4.
Fig. 6 is a graph showing the change in the number of contact points with respect to the depth.
FIG. 7 is a graph of strain as a function of stress for the acetabulum.
FIG. 8 is a graph of deformation of raised areas on the acetabulum as a function of pressure.
FIG. 9 shows the number of dots to be ground off as y 0 The time required versus the amount of force applied.
Fig. 10 is a block diagram of the system of the present invention.
Detailed Description
The present application is further described below with reference to the accompanying drawings.
The present invention provides an embodiment:
in order to solve the problems in the prior art, as shown in fig. 1, the navigation method for assisting the acetabular cup implantation by the acetabular collapse reconstruction technology according to the embodiment specifically includes the following steps:
s1, acetabular part segmentation and modeling:
in conventional segmentation, pre-image segmentation and manual inpainting on CT/MRI images using software adjusted thresholds take a long time.
The embodiment carries out modeling after segmentation on a CT/MRI image of the hip joint position of a patient, and comprises the following specific processes:
s101, CT/MRI image acquisition: using a scanner to obtain CT/MRI data of a pelvic model of a patient and saving the CT/MRI data in a.mha format;
s102, CT/MRI image segmentation: preprocessing the CT/MRI data using a medical image processing software package, such as ITK, insight Toolkit; the image automatic segmentation can be carried out on the CT/MRI image by using a connecting gate image filtering algorithm of a region growing module in an ITK library; wherein, the key parameters include: an upper threshold (upperThreshold), a lower threshold (lowerThreshold) and a seed point selection position; setting the upper threshold value and the lower threshold value to be too close can reduce the mobility of region growing, and setting the upper threshold value and the lower threshold value to be too far away can roll the whole image into the region;
s103, modeling CT/MRI images: processing the pre-processed CT/MRI data using a library of Visualization tools, such as VTK, visualization Toolkit; CT/MRI images can be modeled three-dimensionally using Marching Cubes algorithms (Marching Cubes) in the VTK library, with key parameters including: setting the length of the unit pixel point and the threshold value of the isosurface, such as: comparing the gray value of the CT/MRI image with the threshold value of the isosurface, and displaying when the gray value is smaller than the threshold value of the isosurface;
s104, data derivation and format conversion: as shown in fig. 2 to 3, the built model is exported in stl (streolithograph) format in the VTK; then, converting stl surface grids into volumes by using Gmsh software through Geometry- > Elementary entry- > Add- > Volume, converting the volumes into Volume grids by using Mesh- >3D, and exporting the volumes in a format of msh (Gmsh Mesh); finally, the msh format file is displayed in SOFA (Simulation Open Framework Architecture) through XML language or Python language to obtain the final modeling effect; the grid model of the image reconstruction is converted into a point cloud form, so that the accurate position of each reference point can be well and automatically positioned; in the process, the embodiment uses the connected gate image filtering algorithm to automatically segment the CT/MRI image, and the algorithm has the advantages of high calculation speed, good modeling effect and higher efficiency than the traditional segmentation.
S2, mathematical expression of the acetabular cup:
as shown in figures 4-5, the acetabulum is located in the center of the lateral surface of the hip bone, and is shaped like a semi-ellipsoid deep concave with the diameter of about 30-50mm; compared with an acetabulum with a solid structure, the acetabulum cup has a larger stress distribution range and more uniform stress distribution, thereby reducing the abrasion among hip joint prostheses and reducing the risk of aseptic loosening of the hip joint prostheses; therefore, the shape of the acetabular cup is similar to a concentric semi-ellipsoid;
assuming that the radius of the inner circle of the cup mouth of the acetabular cup is R, the thickness of the acetabular cup is l, and the height from the lowest point of the inner surface of the acetabular cup to the cup mouth is H, as shown in fig. 5, let R = R + l and H = H + l; the cup mouth of the acetabular cup can be regarded as a perfect circle, so that the expression of the surface of the acetabular cup can be directly obtained in the embodiment as
Figure BDA0003164237890000081
Is marked as surface S;
the degree of curvature of the acetabular cup surface can be expressed by curvature, with greater curvature being the greater the degree of curvature; if the parameters of the ellipsoid are expressed as
Figure BDA0003164237890000082
Then this can be obtained from the mathematical expressions of mean curvature G and gaussian curvature K:
Figure BDA0003164237890000083
Figure BDA0003164237890000084
in the step, after the mathematical expression of the acetabular cup is obtained, curvature analysis is performed, and the fit between the surface S of the acetabular cup and the acetabulum of the patient after bruise is improved.
S3, surgical positioning of the acetabular cup:
accurate placement of the acetabular cup is critical to producing a successful clinical outcome, leading to post-operative prosthesis loss and serious complications if the acetabular cup is improperly positioned.
To facilitate positioning of the acetabular cup: setting an auxiliary point p at a position 2cm above the acetabulum in a 12-point direction of the acetabulum, and making a horizontal auxiliary line L at a position 2cm below the point p; when the surface S is below and tangent to the horizontal line L, the point q tangent to the horizontal line L is directly below the point p, which is the point of entry of the acetabular cup, and the current position is denoted as M.
S4, determining the implantation angle and depth of the acetabular cup:
optionally, the implantation angle of the acetabular cup is 40 degrees +/-10 degrees of abduction angle, the anteversion angle is 15 degrees +/-10 degrees, and the dislocation rate of the artificial hip joint is the lowest.
Preferably, the surface S is set to extend outward by 45 ° and incline forward by 15 ° in the present embodiment, and is initially contacted with the acetabulum of the patient at the position M; the depth of the surface S close to the acetabulum of the patient in the patient body is set as B, the number of contact points of the surface S and the acetabulum of the patient is set as W, and the relationship between the depth and the contact points is approximately as follows:
Figure BDA0003164237890000091
wherein σ is the variance of the contact points in the measurement depth range, and x is the mean of the contact points in the measurement depth range. By the above formula, a graph of the number of contact points with respect to the depth is made, as shown in fig. 6; while the number of points per unit area of full contact is calculated to be approximately deltay.
It is to be understood that: the position and the angle of the acetabular cup placement have important influences on the success rate of the acetabular replacement surgery, the subsequent dislocation condition and the hyperplasia condition, and the determined position and angle are the winning schemes in the acetabular replacement surgery.
S5, determining the to-be-milled part of the acetabulum:
according to the following formulaThe analysis of the graph of FIG. 6 selects the depth at which the number of contact points reaches a maximum value, denoted as x 0 When the number of contact points is y 0 (ii) a When the depth is x 0 When the surface S is in contact with the acetabulum of the patient, the contact surface of the surface S and the acetabulum of the patient is the largest; because the acetabulum of the patient still has a raised part which is not matched with the surface S, before the step of installing the acetabulum cup, the process of grinding and contusion is needed. At this time, position data of a position where the surface S is in contact with the bottom of the acetabular model is recorded as a data set J.
S6, determining and modeling a mathematical expression of the frustration tool:
in the process of filing and deepening the acetabulum, the filing tool is generally 2-3mm smaller than the measured size of the acetabular cup, and the shape of the tool is basically consistent with that of the acetabular cup.
In the embodiment, the radius of the grinding tool is less than that of the acetabular cup by alpha, and alpha is more than 2 and less than 3; the height is less than that of the acetabular cup by beta, and the beta is more than 2 and less than 3;
the mathematical formula of the grinding tool is as follows:
Figure BDA0003164237890000101
preferably, the formula is modeled algorithmically on MATLAB.
S7, selecting material properties:
it is well known that different materials, have different elastic limits. In order to obtain the elastic limit of the acetabulum, the material properties of the acetabulum and a bruise tool under the common standard are adopted in the embodiment; preferably, the material properties of the human acetabulum are essentially: the elastic modulus is 20Gpa, the Poisson ratio is 0.3, and the density is 1.7g/cm 3 (ii) a The material properties of the ground tool, such as titanium alloy, are: the elastic modulus is 117.6Gpa, the Poisson ratio is 0.34, and the density is 4.5g/cm 3 。
S8, material assignment:
in order to accurately simulate the force and the tactile feedback effect in the surgical process, the present embodiment utilizes SOFA to assign specific values of material properties to the acetabular model and the brute force tool model; the model is subjected to material assignment in modeling, and the relation between the stress sigma and the strain epsilon on the acetabulum can be judged before an actual experiment.
S9, simulation of elastic limit and strength limit:
when the acetabulum is subjected to an acting force, the shape of the acetabulum changes, and if the external force is removed, the deformation disappears and the acetabulum restores to the original shape. When this force reaches a limit, the acetabulum will plastically deform until it breaks if the force continues to increase, as shown in figure 7. Carrying out stress analysis on the acetabulum with material properties on the SOFA, and fitting out a functional relation expression of stress sigma and strain epsilon on the acetabulum, wherein the functional relation expression is approximately as follows:
Figure BDA0003164237890000111
wherein E is represented by an elastic modulus. The relationship is shown in FIG. 6, where σ E Expressed as elastic limit, σ B Expressed as intensity limits;
based on the fact that the horseshoe fossa at the acetabulum of a human body is filled with fibrous connective tissue, in operation, the lower edge of the horseshoe fossa is usually separated by using an electric knife, and then the fibrous connective tissue above the horseshoe fossa is taken out through rongeur or other instruments, so that bleeding can be reduced.
When direct grinding and contusion are carried out on the acetabulum bottom, namely the bone position, an actual force transmission experiment platform is built, actual force transmission tests of the acetabulum and a grinding and contusion tool are carried out, and a graph that the deformation degree of a convex part on the acetabulum changes along with the increase of pressure can be obtained, such as a graph shown in fig. 8.
The elastic limit and the strength limit, respectively denoted as σ, of the interaction of the acetabulum of the human body with the bruise tool can be determined by means of FIG. 8 0 And σ 1 . If the deformation degree of the raised part on the acetabulum is beta and the pressure is alpha, the expression is approximated as follows:
Figure BDA0003164237890000112
wherein E is expressed as the modulus of elasticity.
S10, obtaining the filing time per unit volume:
unit volume is equal to the product of unit area and unit depth; according to the steps ofStep 9, applying sigma to the area to be milled of the acetabulum 0 ～σ 1 The duration of the milling away of the dead bone per volume is recorded as data set Q; assuming that the required time is T and the force magnitude is N, the expression is approximated as:
Figure BDA0003164237890000113
where k is a constant, the relationship is shown in fig. 8.
S11 three factors of the applied force during the filing:
with respect to the force applied when filing the acetabulum, three factors are considered in this embodiment, including the magnitude of the force, the direction of application, and the time of application.
The magnitude of the force is taken as f, sigma 0 ＜f＜σ 1 (ii) a From fig. 9, the time required to grind off a unit volume can be found, denoted as Δ t. According to S5, the maximum number of contact points is y 0 . Assuming that the desired depth x is just reached from the moment the bruising tool contacts the acetabulum 0 All need to rub off the maximum value y 0 . The time required for grinding the acetabulum per unit depth is
Figure BDA0003164237890000121
Is ground to the ideal depth x 0 The total time required is
Figure BDA0003164237890000122
According to the basic consistency of the grinding tool and the shape of the acetabulum, the direction is consistent with the angle and the position for placing the acetabular cup, namely the acetabulum of the patient is ground and contused at the position M by the angles of abduction 45 degrees and anteversion 15 degrees.
S12, analyzing the effect of the acetabulum after bruise:
after confirming the three factors of the force applied by the filing tool, the results are returned to the automatically controlled filing tool. After the grinding is finished, according to the data set J obtained in the S5, preliminary confirmation of the grinding effect can be obtained; this embodiment takes into account three factors for the force applied by the filing tool: the amount of force, direction of application, and time of application, substantially simulates the effects of force and tactile feedback during the procedure.
The invention also discloses an embodiment:
referring to fig. 10, a navigation system for acetabular collapse reconstruction technique assisted acetabular cup implantation comprises: a graph partitioning module 100, a processing unit 200, and a storage module 300; the graph segmentation module 100 is connected with an external image acquisition device and is used for segmenting the acquired CT/MRI graph of the acetabulum part; the processing unit 200 is connected to the graph segmentation module, and is configured to model the acetabulum part according to the segmented image to obtain an acetabulum model; the storage module 300 is connected with the processing unit and is used for storing an acetabular cup model, a bruise tool model and an acetabular model; the processing unit 200 is in communication with the storage module 300, and is configured to call an acetabular cup model and an acetabular model, and determine a portion to be milled in the acetabular model after initial contact; the processing unit 200 communicates with the storage module 300, and is configured to invoke a frustration tool model and the acetabular cup model for performing frustration simulation.
The invention also discloses an embodiment:
an electronic device for assisting acetabular cup implantation by acetabular collapse reconstruction technology, comprising: a storage medium and a processing unit; preferably, the storage medium is a mobile hard disk or a storage device such as a usb flash disk; a processing unit, preferably a CPU; the processing unit is used for exchanging data with the storage medium and executing the computer program through the processing unit when the acetabulum collapse reconstruction technology-assisted acetabulum cup implantation is carried out, so that the steps of the acetabulum collapse reconstruction technology-assisted acetabulum cup implantation method are carried out.
The CPU described above can execute various appropriate actions and processes according to a program stored in a storage medium. The electronic device also includes peripherals including an input part for a keyboard, a mouse, etc., and an output part such as a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), etc., and a speaker, etc.; in particular, according to the disclosed embodiments of the invention, the process as described in any of fig. 1-9 may be implemented as a computer software program.
The invention also provides an embodiment:
a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising program code for performing the method as illustrated by the flow chart of figure 1. The computer program may be downloaded and installed from a network. The computer program, when executed by the CPU, performs the above-described functions defined in the system of the present invention.
The invention also provides an embodiment:
a computer-readable storage medium having a computer program stored therein; the computer program, when executed, performs the steps of the acetabular collapse reconstruction technique assisted acetabular cup implantation navigation method described above.
In the present invention, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In contrast, in the present invention, a computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, fiber optic cable, RF, etc., or any suitable combination of the foregoing.
The above-mentioned invention numbers are merely for description and do not represent the merits of the implementation scenarios.
The above disclosure is only for a few concrete implementation scenarios of the present invention, however, the present invention is not limited to these, and any variations that can be considered by those skilled in the art are intended to fall within the scope of the present invention.

Claims (9)

1. A navigation method for assisting acetabular cup implantation through acetabular collapse reconstruction technology is characterized by comprising the following steps:
after a CT/MRI image of an acetabulum part is segmented, modeling the acetabulum part to obtain an acetabulum model;
modeling the acetabular cup to obtain an acetabular cup model; positioning the surgical position of the acetabular cup, and obtaining the depth of the acetabular cup and the number of contact points of the acetabular cup and the acetabular cup by utilizing the acetabular cup model to make primary contact with the acetabular cup model;
determining the portion of the acetabulum part of the patient to be bruised according to the depth of the acetabulum cup and the number of contact points of the acetabulum cup and the acetabulum model;
constructing a mathematical expression of the bruise tool, and determining a model of the bruise tool;
assigning the grinding tool model and the acetabulum model to obtain an assigned grinding tool model and an assigned acetabulum model;
carrying out simulation navigation on the assigned acetabulum model by using the assigned frustration tool model, and analyzing the frustrated effect of the acetabulum part;
the step of modeling the acetabular cup comprises:
modeling the acetabular cup using the following equation:
Figure FDA0003745897430000011
and obtaining the degree of curvature of the surface of the acetabular cup according to the mathematical expression of the average curvature G and the Gaussian curvature K and the ellipsoidal parameters:
Figure FDA0003745897430000012
Figure FDA0003745897430000013
wherein R = R + l, H = H + l; the radius of the inner circle of the cup opening of the acetabular cup is r, the thickness of the acetabular cup is l, and the height from the lowest point of the inner surface of the acetabular cup to the cup opening is h; theta represents the angle formed by the connecting line of the point of the calculated curvature and the central point of the cup opening and the cup opening.
2. The navigation method for assisting acetabular cup implantation through acetabular collapse reconstruction technology according to claim 1, wherein the acetabulum site is modeled after the CT/MRI image of the acetabulum site is segmented, and the navigation method comprises the following steps:
obtaining CT/MRI data of a pelvic model of a patient;
automatically segmenting the CT/MRI data to obtain segmented CT/MRI images;
and carrying out three-dimensional modeling on the segmented CT/MRI image.
3. The method for navigating the acetabular collapse reconstruction technique assisted acetabular cup implantation according to claim 1, wherein the positioning the surgical position of the acetabular cup, the obtaining the depth of the acetabular cup and the number of contact points of the acetabular cup with the acetabular cup model by making a preliminary contact with the acetabular cup model comprises:
setting an auxiliary horizontal line at the end of the acetabulum of a patient, and obtaining an entry point position of the acetabular cup according to the auxiliary horizontal line;
making initial contact of the acetabular cup with the patient's acetabulum at the entry point location;
obtaining the number of contact points of the acetabular cup and the acetabulum of the patient according to the depth of the acetabular cup approaching the acetabulum of the patient into the patient;
the determining the portion of the patient's acetabulum site to be bruised based on the depth of the acetabular cup and the number of contact points between the acetabular cup and the acetabular model comprises:
obtaining a maximum number of contact points for the acetabular cup to be in full contact at the patient's acetabulum;
contacting the acetabular cup with the acetabulum of the patient at the inlet point position, and acquiring the number of first contact points of the acetabular cup and the acetabulum of the patient at the maximum depth;
and when the number of the first contact points is less than the maximum number of the contact points, recording corresponding contact positions and determining the contact positions as parts to be subjected to frustration.
4. The navigation method for assisting in implanting the acetabular cup by the acetabular collapse reconstruction technique according to claim 3, wherein the obtaining the number of contact points of the acetabular cup with the acetabulum of the patient according to the depth of the acetabular cup approaching the acetabulum of the patient into the patient comprises:
obtaining the number W of contact points of the acetabular cup and the acetabulum of the patient by the following formula:
Figure FDA0003745897430000031
where σ is the variance of the contact points within the measurement depth range,
Figure FDA0003745897430000032
the mean value of the contact points in the measuring depth range; and B is the depth of the acetabulum cup approaching the patient body at the acetabulum of the patient.
5. The method for navigation of acetabular collapse reconstruction technology-assisted acetabular cup implantation according to claim 1, wherein the constructing a mathematical expression of a bruise tool, and the determining a bruise tool model, comprises:
the mathematical formula of the filing tool is as follows:
Figure FDA0003745897430000033
wherein R = R + l, H = H + l; the radius of the inner circle of the cup opening of the acetabular cup is r, the thickness of the acetabular cup is l, and the height from the lowest point of the inner surface of the acetabular cup to the cup opening is h; alpha is more than 2 and less than 3;beta is more than 2 and less than 3; wherein R-alpha is the radius of the rasping tool; h-beta is the height of the tool.
6. The navigation method for assisting acetabular cup implantation through acetabular collapse reconstruction technology according to claim 1, wherein the simulation navigation of the assigned acetabular model by using the assigned frustration tool model and the analysis of the effect of the acetabular site after frustration comprise:
carrying out a simulation process of elastic limit and strength limit on the acetabulum; and/or the presence of a gas in the atmosphere,
obtaining the grinding time per unit volume; and/or the presence of a gas in the atmosphere,
determining an amount of force applied, a direction of application, and a time of application while the acetabulum is being debugged.
7. An acetabular collapse reconstruction technology-assisted acetabular cup implantation navigation system, which is applied to the acetabular collapse reconstruction technology-assisted acetabular cup implantation navigation method according to any one of claims 1 to 6, and is characterized by comprising:
the image segmentation module (100) is connected with an external image acquisition device and is used for segmenting the acquired CT/MRI image of the acetabulum part;
the processing unit (200) is connected with the graph segmentation module and is used for modeling the acetabulum part according to the segmented images to obtain an acetabulum model;
a storage module (300) connected with the processing unit for storing an acetabular cup model, a bruise tool model and an acetabular model;
the processing unit (200) is in communication with the storage module (300) and is used for calling the acetabular cup model and the acetabular model, and determining a part to be milled in the acetabular cup model after initial contact;
the processing unit (200) is in communication with the memory module (300) for invoking a bruise tool model and the acetabular cup model for performing a bruise simulation.
8. An electronic device for assisting acetabular cup implantation by acetabular collapse reconstruction technology, comprising:
a storage medium for storing a computer program;
a processing unit, in data communication with the storage medium, for executing the steps of the navigation method for acetabular collapse reconstruction technique assisted acetabular cup implantation according to any one of claims 1 to 6 by executing the computer program through the processing unit when acetabular collapse reconstruction technique assisted acetabular cup implantation is performed.
9. A computer-readable storage medium, characterized in that:
the computer readable storage medium has stored therein a computer program;
the computer program when executed performs the steps of the navigation method of acetabular collapse reconstruction technique assisted acetabular cup implantation according to any one of claims 1 to 6.
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