KR102181399B1 - An elastic modulus adjustment method for implants having lattice scaffolds structure and patient specific surgical implants which use the method - Google Patents

Abstract

The present invention relates to a method for adjusting the elastic modulus of a patient-specific implant that adjusts the elastic modulus of the implant. In the method of adjusting the elastic modulus of an implant according to the present invention, the method comprising: specifying a region requiring implantation from a CT scan image of the affected region; Setting an implant shape to be inserted in the specified region; Dividing the implant shape into a plurality of three-dimensional regions; Providing a target elastic modulus (Et) for each of a plurality of divided 3D regions; Selecting any one of a plurality of grid-shaped scaffold structures for the implant shape; Selecting a 3D printed molding material for the implant shape; And a scaffold structure selected so that the elastic modulus (Eh) to be molded for each of a plurality of three-dimensional areas divided based on the basic elastic modulus (Eo) of the selected 3D printing molding material is within a predetermined error from the target elastic modulus (Et). It characterized in that it comprises the step of calculating the diameter and density of the brace. Since the implant according to the present invention does not cause stress shielding by adjusting the elastic modulus of the implant to be similar to the elastic modulus of the implant, the implant can be used for a long time without reoperation.

Description

An elastic modulus adjustment method for implants having lattice scaffolds structure and patient specific surgical implants which use the method}

The present invention relates to a method for adjusting the modulus of elasticity of an implant having a lattice scaffold structure and a patient-customized surgical implant according to the method.

An artificially manufactured implant can be inserted into the patient's bones or tissues using surgical procedures. In the field of tissue engineering, which artificially manufactures human tissue and uses it for surgical operation, the term'scaffold' refers to a grid-shaped scaffold-shaped structure used in the architectural field. On the other hand,'implant' is widely used in the medical field as an artificial organ or artificial joint.

On the other hand, implants such as artificial joints are usually made of titanium (Ti), and when an implant made of titanium is inserted into an implanted part such as an existing human bone by surgical operation, the elasticity of the bone Since the modulus and the modulus of elasticity of titanium are different, there is a problem in that the bone in which the titanium implant is inserted is deformed or the shape is deformed, requiring reoperation several years later when subjected to repeated use and stress.

This problem is referred to as stress shielding, and due to this stress shielding phenomenon, there is a hassle that must be reoperated after a certain time after implant surgery.
(Prior technical literature) 1.US 7,174,282 B2 (registration date 2007. 2. 6), 2. US 2014/0363481 A1 (publication date 2014. 12. 11)

It is an object of the present invention to produce and install an implant in a grid-shaped scaffold structure for the manufacture of implants such as artificial bones, artificial joints, and artificial teeth, so that the same elastic modulus as that of the other part of the human body into which the implant is inserted. It is to provide an implant that can be used for a long time by adjusting it to have.

Another object of the present invention is to provide an implant with a patient-customized grid-shaped scaffold structure to adjust to be similar to the elastic modulus of the inserted part, and to make the elastic modulus of each part of the implant different from each other so that the most optimal modulus of elasticity is obtained. The branch is to provide the implant.

The present invention for achieving the object as described above, in a method for adjusting the elastic modulus of an implant, the steps of specifying a region requiring implantation from a CT scan image of the affected area; Setting an implant shape to be inserted into the specified region; Dividing the implant shape into a plurality of three-dimensional regions; Providing a target elastic modulus (Et) for each of the divided 3D regions; Selecting any one of a plurality of lattice-shaped scaffold structures for the implant shape; Selecting a three-dimensional printing molding material for the implant shape; And the elastic modulus (Eh) to be molded for each of the divided 3D regions based on the basic elastic modulus (Eo) of the selected 3D printing molding material is within a predetermined error from the target elastic modulus (Et). And calculating the diameter and density of the braces of the selected scaffold structure. In the method for adjusting the elastic modulus of an implant according to the present invention, the shape of the implant is set based on the CT scan image, and the target elastic modulus of the implant is set from the elastic modulus of the inserted site based on the bone density information of the area to be inserted. , The elastic modulus of the implant and the blood into which the implant is inserted through the process of obtaining the basic modulus of elasticity from the material of the implant and obtaining the size of the unit area of the implant, the support diameter and the density of the implant to have a molding modulus similar to the target modulus of elasticity. The elastic modulus of the body part of the insertion part is similarly matched.

The plurality of divided 3D regions are composed of a plurality of 3D voxel meshes, and the step of assigning a target elastic modulus for each of the divided 3D regions may include Bone density for each of the plurality of 3D voxel meshes. It characterized in that it comprises the step of extracting information. The implant and the body's bone are integrated into a voxel mesh corresponding to a three-dimensional region, and bone density information is extracted for each voxel mesh, and a target elastic modulus for each region is set.

Some adjacent regions of the divided 3D regions have different target modulus of elasticity, and the adjacent partial regions are connected to each other in a state in which the diameter and the density of the brace are different from each other. In the method for adjusting the elastic modulus of an implant according to the present invention, adjacent regions of a three-dimensional region are coupled to be connected to each other. Instead, the diameter and density of the braces can be set differently from each other.

The object is another aspect of the present invention, in a patient-tailored surgical implant, comprising an implant formed of an insertion portion and a non-insertion portion to be inserted into a specific portion of the patient and formed of a three-dimensional molding material, the implant, Any one of the steps of partitioning the implant shape into a plurality of three-dimensional regions, providing a target elastic modulus (Et) for each of the divided three-dimensional regions, and a plurality of grid-shaped scaffold structures for the implant shape. And a predetermined error between the target elastic modulus (Et) and the elastic modulus (Eh) to be molded for each of the divided 3D regions based on the basic elastic modulus (Eo) of the 3D printing molding material. After adjusting the modulus of elasticity of the implant including calculating the diameter and density of the brace of the selected scaffold structure to be within the range, the implant uses the adjusted diameter and the density of the brace of the selected scaffold structure. It is also achieved through patient-specific surgical implants characterized in that it is manufactured by three-dimensional molding. The patient-customized surgical implant of the present invention acquires a CT scan image of an actual patient's affected area, makes the CT scan image three-dimensional, and then designs an implant shape for a specific area, and the implant and the implant to be inserted into the human body After adjusting so that the elastic modulus of the human body of the inserted part is similar, the implant is manufactured by 3D printing process. Therefore, the implant according to the present invention can be manufactured tailored to the patient, and since the elastic modulus of the implant and the elastic modulus of the bone of the implant into which the implant is inserted are similar, stress shielding does not occur. Can be used.

The plurality of divided 3D regions are composed of a plurality of 3D voxel meshes, and the step of assigning a target elastic modulus for each of the divided 3D regions may include Bone density for each of the plurality of 3D voxel meshes. It characterized in that it comprises the step of extracting information.

Some adjacent regions of the divided 3D regions have different target modulus of elasticity, and the adjacent partial regions are connected to each other in a state in which the diameter and the density of the brace are different from each other.

The method for adjusting the elastic modulus of an implant having a grid-shaped scaffold structure according to the present invention having the above configuration and a patient-specific surgical implant according to the present invention are stress shielded by adjusting the elastic modulus of the inserted part to be similar to the elastic modulus of the implant. Since stress shielding does not occur, the implant can be used for a long time. Therefore, there is an effect of reducing the pain of the patient due to the conventional frequent reoperation.

1 is a flow chart showing the steps of manufacturing a patient-specific implant according to the present invention.
2 is a conceptual diagram showing a step of manufacturing a patient-customized implant according to the present invention into a shape.
3 is a flow chart according to the first embodiment showing a process according to an algorithm for designing a step of manufacturing a patient-customized implant according to the present invention based on a predetermined unit 3D voxel mesh.
4 is a flow chart according to a modified embodiment showing a process according to an algorithm for designing a step of manufacturing a patient-customized implant according to the present invention based on a predetermined unit 3D voxel mesh.
5 is a conceptual diagram showing the type of a unit grid structure of a unit 3D voxel mesh of a patient-customized implant according to the present invention.
6 is an embodiment showing the design of an implant applied to a femur (Femur) among patient-specific implants according to the present invention.
7 is an embodiment showing the design of a spinal implant (Lumbar Interbody Fusion) used for spinal fixation among patient-specific implants according to the present invention.
Figure 8 is an embodiment showing the design of the stem (Hip Stem) portion of the hip joint of the patient-specific implant according to the present invention.
9 shows a graph of the correlation of the metamodel according to the grid size, density, and normalized elastic modulus values according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Features and advantages of the present invention become more apparent from the description of the preferred embodiments based on the accompanying drawings.

1 is a flow chart showing the steps of manufacturing a patient-specific implant according to the present invention.

As the life span of humans is prolonged due to the development of scientific and technological civilization, damage to the bones, joints and teeth of the body is occurring due to stress, obesity, cancer, and various accidents. Artificial bones, artificial joints, and artificial teeth to recover them Research on implants such as these is progressing rapidly.

The implant must be non-toxic and must be able to maintain its original function while harmonizing with the biological tissue of the implanted part into which the implant is inserted. Efforts have been made to develop excellent biomaterials for implants, but the modulus of elasticity of biomaterials currently applied to implants differs considerably from the elastic modulus of biological tissues of the implanted part such as bone (approximately 3-10 times). Therefore, 2 to 4 years after the transplantation procedure, stress shielding occurs in vivo, and a reoperation due to the side effects is considered.

If the difference in elastic modulus between the bone and the implant in the biological tissue where the implant is inserted is large, the implant with a high modulus of elasticity supports most of the stress transmitted to the bone, and the bone of the human body, the biological tissue in the implant, is long-term. As a result, when tension, compression, bending moment, etc. are not received, the human tissue automatically recognizes that the role of bone is not necessary, and the thickness and weight of the bone are reduced, resulting in osteoporosis around the implant. .

Eventually, a problem that requires a re-operation due to the weakening of the coupling between the implant and the bone of the implanted portion appears as the stress shielding phenomenon of the implant. Therefore, when a stress shielding phenomenon occurs, the bone density around the implant decreases and the implant is easily separated from the implant site over time.In the case of an implant using a metal material, the strength is considerably higher than that of the bone, so that the bone tissue in the surrounding region is reduced. It also destroys.

Titanium alloy (Ti-6Al-4V), a representative implant material used today, as well as titanium alloys that combine tantalum, palladium, zirconium, and niobium, are also used as implant materials.

The present invention is a method of adjusting the elastic modulus value of the inserted human tissue (bone) into which the implant is inserted and the elastic modulus of the implant, irrespective of the type of implant material, as well as the previously developed implant materials as well as implant materials developed in the future. Applicable.

In the present invention, first, a CT scan image is obtained through a CT scan of an affected part of a patient, and a region requiring an implant procedure is specified. (S100)

In the present invention, it is possible to manufacture a customized implant for a patient by obtaining a CT scan image of a patient's affected area.

The CT scan image is a two-dimensional image, and by stacking this two-dimensional CT scan image, it is possible to create a three-dimensional bone model image for the affected area, and the shape of the implant to be inserted and the implant to be inserted from the three-dimensional bone model image It is possible to design a shape for human tissue (bone). In addition, to design the shape of the implant, a unit 3D voxel mesh corresponding to each position is generated from the 3D bone model image, and bone density information for each voxel mesh is extracted. (S200)

The unit 3D voxel mesh is the basis of the implant shape set from the 3D bone model image, and in response to the implant shape, the 3D bone model image is divided into a plurality of 3D regions. It corresponds to the unit division area.

Bone density information for each location distributed throughout the human tissue (bone) of the inserted part is extracted from the 3D bone model image. As a result, the mechanical properties or elastic modulus of the implant are adjusted for each location based on the bone density information of the human tissue to be inserted into the implant.

In general, the elastic modulus of bone is about 5 GPa, the area that receives a lot of load is about 10-40 GPa, and the elastic modulus of titanium, which is widely used as an implant material, is about 110 GPa, which is approximately 3 to 10 times the difference in elastic modulus.

Based on the extracted bone density information, a target elastic modulus is assigned for each voxel mesh. (S300)

The target modulus of elasticity is given to each voxel mesh, based on bone density information, which shows a highly correlated mechanical property. For the correlation between the bone density and the mechanical properties of the bone, and the formula for calculating the elastic modulus using bone density, reference may be made to publicly known data (References 9 and 10) disclosed in the priority application (US 62/626,749) of the present invention.

The next step is to resize each voxel mesh and select the type of grid-shaped scaffold, and create a grid-shaped scaffold. (S400) Detailed information about this will be described later.

The lattice-shaped scaffold means a scaffold-like structure used in buildings, and has a plurality of types of lattice-shaped scaffold structures described later. One of these scaffolds with a lattice shape is selected, and this lattice-shaped scaffold corresponds to a unit structure in which a unit voxel mesh is formed by a 3D printer. At this time, the 3D printed unit scaffold creates a detailed structure to have an elastic modulus similar to the target elastic modulus.

In the final step, the design of the customized implant is completed using the generated grid-shaped scaffold, and the implant is manufactured according to the design. (S500)

The lattice-shaped scaffold is a structure related to the unit shape of a three-dimensional object, and the plurality of unit shapes are stacked and bonded to each other in three dimensions to complete an object corresponding to the set implant shape.

2 is a conceptual diagram showing a step of manufacturing a patient-customized implant according to the present invention into a shape.

FIG. 2 is described more easily by forming the flowchart of FIG. 1 into a figure.

In (a) of FIG. 2, the patient's CT scan image of the femur is in a 2D state, but the 3D bone model image is created by stacking it, and corresponding to the area corresponding to the treatment site based on the 3D bone model image. It shows a drawing that generates a voxel mesh, which is a plurality of three-dimensional unit images. In addition, a bone density value of each voxel is extracted from gray scale information of a CT image of a corresponding region represented by a 3D voxel mesh. Each voxel is expressed in white as the bone density is higher, and gray or darker if the bone density is low. The target elastic modulus for each voxel mesh of the implant is set by using the elastic modulus of the bone from each bone density.

Figure 2(b) shows the process of (1) adjusting the initial voxel mesh, (2) adjusting the size of the voxel mesh, (3) creating the grid-shaped scaffold, and (4) adjusting the grid-shaped scaffold. .

In the case of the initial voxel mesh, the image data representing the bone density value is followed as it is, but since the size of each unit voxel mesh is small, it is often not possible to fabricate it as an actual implant scaffold, so a resize process is basically required.

It is necessary to readjust the size of the basic voxel mesh to 2mm to 6mm for 3D molding. After resizing the voxel mesh, a scaffold is created by selecting one of a plurality of scaffold types. In the present invention, the size can be adjusted while minimizing loss of image data by using a structural similarity index method when resizing the voxel.

After the scaffold is created, the type, density, and strut diameter of each grid-shaped scaffold are adjusted using the algorithm of the present invention to obtain the desired mechanical properties, that is, the target elastic modulus for each grid corresponding to each voxel mesh. I can.

In the case of Fig. 2 (b) (3), the diameter of the grid-shaped brace is constant throughout the region, but in the case of Fig. 2 (b) (4), the target elastic modulus is reflected for each grid, and the brace diameter changes. Show Accordingly, the braces for each grid of a voxel mesh region having a relatively high bone density (eg, a white region) may be set to have a larger diameter than a voxel mesh region having a relatively low bone density (eg, a gray or black region).

3 is a flow chart according to the first embodiment showing a process according to an algorithm for designing a step of manufacturing a patient-customized implant according to the present invention based on a predetermined unit 3D voxel mesh.

It is divided into a plurality of three-dimensional regions corresponding to the shape of the implant of the present invention, and the divided three-dimensional unit shape corresponds to a three-dimensional voxel mesh.

In the step of manufacturing a patient-specific implant of the present invention, the shape of the implant corresponding to the area set from the CT scan image of the treatment site is designed, and a target elastic modulus (Et) is calculated for each 3D voxel mesh for the shape of the designed implant. Grant. (S10)

The target elastic modulus (Et) is a value set for each voxel mesh according to the bone density information of the CT scan image as described above, or the most appropriate elastic modulus according to the patient's gender, age, and characteristics of the affected area, for example, a predetermined constructed Based on the database, it is also possible to enter.

Select any one of a plurality of lattice scaffold shapes. (S20)

The shape of a plurality of scaffolds will be described later with reference to FIG. 5.

Various lattice structures are created with respect to the scaffold density (ρ). (S30)

Since the density (ρ) of the scaffold is the ratio of the unit size to the total volume of the part to be molded, a density of 1.0 means that the solid is filled within a unit volume, and a density of 0.0 means that the unit is molded within the unit volume. It means that it is filled with only the parts that are not.

Calculate the brace diameter (D) for each density. (S40)

When the density changes to 0.2, 0.3, 0.4, 0.5, etc., the diameter of the brace per unit voxel mesh and the density at this time can be derived by calculation formulas, respectively.

A meta-model of the correlation between the brace diameter (D) and the elastic modulus of the implant is created. (S50)

A meta-model of the correlation between the elastic modulus of the implant based on the homogeneous modulus of elasticity (Eh) of the molded implant to be matched with the brace diameter (D) in the grid shape is generated.

The implant elastic modulus is calculated using the multi-scale modeling method using the brace diameter and density for each grid structure. (S60)

The implant modulus corresponds to the value of the modulus of elasticity normalized to the value of the homogeneous elastic modulus generated using the material of the implant, and can be obtained using the multiscale modeling method. Once the normalized elastic modulus value and meta-model of the type, size, and brace diameter of the grid structure are created, the user selects the target elastic modulus value without additional calculations, and the corresponding grid shape type, size, and brace diameter Etc. can be obtained using a meta model. The correlations such as grid size, density and normalized elastic modulus values, etc., by this metamodel can be expressed as a multidimensional graph. (See Fig. 9 (a), (b)). 9 is a graph showing the correlation graph of the metamodel according to the grid size (L), density (ρ), and normalized elastic modulus value (Eh/Eo) according to the present invention.

The normalized elastic modulus value is expressed as a value calculated by dividing the homogeneous modulus of elasticity (Eh) by the basic modulus of elasticity (Eo) of the implant molding material, that is, Eh/Eo. Therefore, it is possible to obtain the brace diameter and density for each grid structure, and check whether the elastic modulus (Eh) of the molded implant is close to the target modulus of elasticity (Et) using the basic modulus of elasticity (Eo) of the molding material at this time. It is possible. This can be easily selected according to the basic modulus of elasticity (Eo) given for each implant molding material by building a database experimentally.

Find the brace diameter for matching the target elastic modulus (Et) using the meta model. (S70)

Using the above-described correlation meta-model as it is, by matching the normalized elastic modulus value (Eh/Eo) according to the basic elastic modulus (Eo) given differently for each implant molding material, and the target elastic modulus (Et), The brace diameter (D) can be obtained.

Acquire the matched design values (brace diameter and density). (S80)

4 is a flowchart according to a modified embodiment showing a process according to an algorithm for designing a step of manufacturing a patient-customized implant according to the present invention based on a predetermined unit 3D voxel mesh.

In the step of manufacturing a patient-specific implant according to a modified embodiment of the present invention, the shape of the implant corresponding to the region set from the CT scan image of the treatment site is designed, and the shape of the designed implant is targeted for each 3D voxel mesh. It gives the modulus of elasticity (Et). (S15)

The target elastic modulus (Et) is a value set for each voxel mesh according to the bone density information of the CT scan image as described above, or the most appropriate elastic modulus according to the patient's gender, age, and characteristics of the affected area, for example, a predetermined constructed Based on the database, it is also possible to enter.

Select any one of a plurality of lattice scaffold shapes. (S25)

The shape of a plurality of scaffolds will be described later with reference to FIG. 5.

Select the initial density (ρ) of the lattice-shaped candidate group. (S35)

Since the density of the scaffold (ρ) refers to a portion of the total volume that is molded per unit size, a density of 1.0 means that the solid is filled within a unit volume, and a density of 0.0 means that the unit is molded within a unit volume. It means to form a hole that is not.

An optimal design method is performed to minimize the difference between the target elastic modulus value (Et) and the design elastic modulus value, that is, the homogeneous elastic modulus value (Eh). (S45)

In other words, unlike the embodiment of FIG. 3, the meta-model of the correlation between the lattice structure and the elastic modulus is not generated.

A homogeneous modulus value (Eh) corresponding to the implant modulus is calculated using the multiscale modeling method. (S55)

The multiscale modeling method is the same as in the embodiment of FIG. 3. If the target elastic modulus value Et is determined, an arbitrary lattice structure is generated, the corresponding density and brace diameter are obtained, and a homogeneous elastic modulus value Eh can be obtained.

Calculate the scaffold brace diameter (D). (S65)

According to the optimal design method, the brace diameter (D) that minimizes the difference between the target modulus value (Et) and the design modulus value, that is, the homogeneous modulus value (Eh) can be obtained.

It is determined whether the difference between the target elastic modulus value Et and the design elastic modulus value Eh is within a predetermined error range. (S75)

If the difference between the target elastic modulus value (Et) and the design elastic modulus value (Eh) is within a predetermined error range, the design variable values (brace diameter and density) of the implant are obtained. (S95)

Optimal design to minimize the difference between the target elastic modulus value (Et) and the design elastic modulus value (Eh) by feeding back again if the difference between the target elastic modulus value (Et) and the design elastic modulus value (Eh) is not within a predetermined error range Repeat the method. (S85)

Accordingly, through the optimal design method of the present embodiment, the process of changing various design variable values such as the brace diameter (D), the density, the type and size of the lattice structure can be repeatedly performed.

5 is a conceptual diagram showing the type of a unit grid structure of a unit 3D voxel mesh of a patient-customized implant according to the present invention.

A plurality of unit shapes of the 3D voxel mesh according to the present invention are presented, and any one shape is selected.

5 shows (a) Crossed, (b) Cantley, (c) Octet, (d) Paramount1, (e) Diagonal, (f) Paramount2, (g) among the unit grid structures corresponding to the plurality of voxel mesh regions. Each of the midpoint types is shown. The present invention is a method that can be applied to all grid structures regardless of the shape of the unit grid structure, and may be applied to other shapes in addition to the unit grid structure illustrated in FIG. 5. The above-described embodiment of FIG. 2 uses a unit lattice structure of a body-centered cubic (BCC) structure.

6 is an embodiment showing the design of an implant applied to a femur (Femur) among patient-specific implants according to the present invention.

For example, the patient's affected part is the femur, and when bone cancer occurs in a partial area of the femur, a procedure in which the area corresponding to the lesion where the bone cancer has occurred is inserted to replace an artificial implant.

The femur implant 100 is inserted into an artificial femur to be inserted by replacing the bone cancer region in which bone cancer has occurred in the femur. Symbol 150 in the drawing corresponds to the femoral implant to be inserted 150.

The femur implant 100 can be divided into a first femur implant 100-1 and a second femur implant 100-2 according to the unit grid size, and the first femur implant 100-1 has a unit grid size of 2 mm. , The second femur implant 100-2 is a case where the unit grid size is 4mm.

The first femur implant 100-1 is formed by stacking a plurality of first size unit grids 100-1-1, and the first size unit grid 100-1-1 has a unit size of 2mm.

The second femur implant 100-2 is formed by stacking a plurality of second size unit grids 100-2-1, and at this time, the second size unit grid 100-2-1 has a unit size of 4mm.

The target elastic modulus (Et) of the affected area specified in FIG. 6 was determined to be suitable for 15 GPa, and the elastic modulus of the titanium alloy (Ti6Al4V), which is a commercially used implant material, is 110 GPa (Eo = 110 GPa), but FIG. 6 The final adjusted grid-shaped scaffold structure as shown in (b) of above is the target modulus value and the target modulus value in two designs with unit grid sizes of 2mm and 4mm of the unit grid structure (eg, BCC unit grid structure) even if the same titanium alloy is used. It shows that 15 GPa was obtained with the matching design modulus value (Eh), and the density and brace diameter at this time were density (ρ) = 0.3662, D = 0.6090 mm (for size 2 mm), and density (ρ )=0.4375, D = 1.3620 mm (for size 4 mm).

7 is an embodiment showing the design of a spinal implant (Lumbar Interbody Fusion) used for spinal fixation among patient-specific implants according to the present invention.

The spinal implant 300 of FIG. 7 uses a BCC unit grid structure in which five spinal implant unit grids 300-1 having a size of 4 mm are stacked horizontally, two vertically, and two heights. It corresponds to an example manufactured in a size of 8 x 8 x 20 mm in shape.

Spinal implants (Lumbar Interbody Fusion) also have the same side effects due to the stress shielding of artificial joints due to the difference in elastic modulus between bone and implant material. Therefore, in the embodiment of the present invention, when the target elastic modulus (Et) of the spine is set to 3 GPa, and the spinal implant 300 is made of a titanium alloy having a basic elastic modulus (Eo) of 110 GPa, the elastic modulus is Adjust the same using the density and the diameter of the brace.

7(b) shows an embodiment of a spinal implant manufactured with a design elastic modulus (Eh), a density ρ = 0.2263, and a brace diameter D = 0.9155 matching the target elastic modulus value (Et = 3GPa) in the case of a grid size of 4 mm. Show the case.

Figure 8 is an embodiment showing the design of the stem (Hip Stem) portion of the hip joint of the patient-specific implant according to the present invention.

The artificial hip joint implant 200 using the present invention is inserted into the hip joint implant insertion part 250, which is a living body tissue of the human body.

The hip implant 200 according to the present invention includes a first hip implant region 210, a second hip implant region 220, and a third hip implant region 230 for each region. The first to third regions are designed to have different brace diameters and densities according to the size, depth, and relative bone density of the implanted portion of each implant.

The hip implant 200 according to the present invention shows an example in which the entire region is matched according to the distribution of the elastic modulus value of the bone of the patient's treatment site for each region. Unlike the embodiment having the BCC unit lattice structure of Figs. 6 and 7, this embodiment distributes the tetrahedral unit lattice structure over the entire area.

The hip implant 200 according to the present invention applies the bone density extraction process from the patient's CT image, and the stem of the artificial hip joint is inserted deeply into the bone based on the CAD model of the site where the artificial hip implant 200 is being treated. From the CT scan image of the patient, the target elastic modulus is designed to have various elastic modulus values ranging from 9 GPa to 124 MPa over the entire area.

As shown in Fig. 8(b), the hip joint implant second region 220, which is a region with high bone density, has a high grid-like density and has a thick brace diameter, and the hip joint implant first region 210 and the hip joint implant are made. The third region 230 has a lower density than the second hip implant region 220 and has a thinner diameter of the brace.

Examples and embodiments of the present invention have calculated the brace diameter and density, for example, when the implant material is a titanium alloy as an example and the elastic modulus is 110 GPa, but the same method can be applied to other implant materials. However, it is possible to determine the shape of the 3D implant, select the unit grid structure, and select different densities and diameters of the braces according to the selection of the shape, size, density, and material of the unit grid structure. All are included in the present invention.

100: femur implant
100-1: first femur implant
100-1-1: 1st size unit grid
100-2: 2nd femur implant
100-2-1: 2nd size unit grid
150: femur implant to be inserted
200: hip joint implant
210: hip joint implant first region
220: hip joint implant second area
230: hip joint implant third area
250: hip joint implant to be inserted
300: spinal implant
300-1: spinal implant unit grid

Claims (6)

In the method of adjusting the elastic modulus of an implant,
Specifying a region requiring implantation from the CT scan image of the affected region;
Setting an implant shape to be inserted into the specified region;
Dividing the implant shape into a plurality of three-dimensional regions;
Providing a target elastic modulus (Et) for each of the divided 3D regions;
Selecting any one of a plurality of lattice-shaped scaffold structures for the implant shape;
Selecting a three-dimensional printing molding material for the implant shape; And
Based on the basic elastic modulus (Eo) of the selected 3D printing molding material, the selected elastic modulus (Eh) to be formed for each of the divided 3D regions is within a predetermined error from the target elastic modulus (Et). Comprising the step of calculating the diameter and density of the brace of the scaffold structure, the method of adjusting the modulus of elasticity of the implant.
The method of claim 1,
The plurality of divided 3D regions are made of a plurality of 3D voxel meshes,
The step of providing the target elastic modulus for each of the divided 3D regions comprises extracting bone density information for each of the plurality of 3D voxel meshes.
The method of claim 1,
Some of the adjacent regions among the divided three-dimensional regions have different target elastic modulus,
Wherein the adjacent partial regions are connected to each other in a state in which the diameter and the density of the brace are set differently from each other.
In the patient-specific surgical implant,
Including an implant formed of a three-dimensional printing molding material consisting of an insertion portion and a non-insertion portion to be inserted into a specific area of the patient,
The implant,
From the CT scan image of the affected area, the area requiring implantation is specified, and the shape of the implant to be inserted into the specified area is set,
Any one of the steps of partitioning the implant shape into a plurality of three-dimensional regions, providing a target elastic modulus (Et) for each of the divided three-dimensional regions, and a plurality of grid-shaped scaffold structures for the implant shape. And a predetermined error between the target elastic modulus (Et) and the elastic modulus (Eh) to be molded for each of the divided 3D regions based on the basic elastic modulus (Eo) of the 3D printing molding material. After adjusting the elastic modulus of the implant, including calculating the diameter and density of the brace of the selected scaffold structure to be within the range,
A patient-specific surgical implant, characterized in that the implant is manufactured by three-dimensional molding using the adjusted diameter and the density of the brace of the selected scaffold structure.
The method of claim 4,
The plurality of divided 3D regions are made of a plurality of 3D voxel meshes,
The step of providing the target elastic modulus for each of the divided 3D regions includes extracting bone density information for each of the plurality of 3D voxel meshes.
The method of claim 4,
Some of the adjacent regions among the divided three-dimensional regions have different target elastic modulus,
The adjacent portion of the surgical implant, characterized in that connected to each other in a state in which the diameter and the density of the brace are set differently from each other.

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