CN110575289B

CN110575289B - 3D printing method for bone defect prosthesis

Info

Publication number: CN110575289B
Application number: CN201910902103.XA
Authority: CN
Inventors: 王富友; 黎川; 陈军; 张资雨; 陈志康
Original assignee: Chongqing Xinsuo Pharmaceutical Technology Co ltd; First Affiliated Hospital of Army Medical University
Current assignee: Chongqing Xinsuo Pharmaceutical Technology Co.,Ltd.; Nanfang Hospital
Priority date: 2019-09-20
Filing date: 2019-09-20
Publication date: 2021-10-22
Anticipated expiration: 2039-09-20
Also published as: CN110575289A

Abstract

The invention relates to a 3D printing method of a bone defect prosthesis, which belongs to the technical field of bone prosthesis manufacture and comprises the following steps: establishing a bone defect model: constructing a three-dimensional mathematical model of the bone defect by utilizing a CT or MRI technology; establishing a prosthesis model; compiling a printing program; trial printing: printing: printing the prosthesis layer by layer; starting a heat preservation device in the printing table to keep the temperature of the contact surface of the printing table and the prosthesis consistent; cooling: after printing is finished, rotating the printing table to perform air cooling; the prosthesis is removed and printing is complete. According to the invention, through the gradient structure of the support framework layer and the fusion layer, the structural strength of the bone prosthesis can be ensured, the functionality of the bone prosthesis can be realized, and the bonding strength of the bone prosthesis can be increased through the bonding between the fusion layer and the natural bone.

Description

3D printing method for bone defect prosthesis

Technical Field

The invention relates to the technical field of bone prosthesis manufacturing, in particular to a 3D printing method of a bone defect prosthesis.

Background

The 3D printing is a direct digital manufacturing, has fast molding and low manufacturing cost, and is widely applied to model manufacturing in the fields of mold manufacturing, industrial design and the like. In recent years, with the rapid development of biotechnology, the medical field gradually improves the product forming efficiency and shortens the recovery period through the 3D printing technology.

However, 3D printing technology only gives a general idea: the product is gradually formed by the accumulation of material. In specific applications, there are many problems, such as heat generated during printing may form thermal stress, cause deformation problems such as product warpage, etc., severe quality problems such as cracks, shrinkage porosity, etc., and also may have problems that the bonding force between the same material or different materials is not enough.

When the above problems exist in the bone prosthesis, the prosthesis may not be attached to the defect of the human body, so that the fixation is not good, or the mechanical properties of the prosthesis are not sufficient, so that functional replacement cannot be performed.

Meanwhile, the bone prosthesis in the prior art is printed by basically adopting one material of titanium or tantalum, and if only titanium is used, the bonding force between the bone prosthesis and the defect part of the human body is not enough due to insufficient affinity with the human body; if tantalum is used alone, the weight is too heavy and the price is too expensive.

Disclosure of Invention

In view of the above, the present invention provides a 3D printing method for a bone defect prosthesis, which uses titanium and tantalum for composite gradient printing and adds a stress prevention measure to solve the problems of insufficient affinity, excessive weight, high price, deformation, cracks and shrinkage porosity caused by thermal stress in the prior art using a single material.

The invention is realized by the following technical scheme:

A3D printing method of a bone defect prosthesis comprises the following steps:

1) establishing a bone defect model: constructing a three-dimensional mathematical model of the bone defect by utilizing a CT or MRI technology;

2) establishing a prosthesis model: constructing a prosthesis model according to the defect condition of the three-dimensional mathematical model, wherein the prosthesis model is a multi-layer composite structure, the composite structure at least comprises a support framework layer and a fusion layer arranged outside the support framework layer, and a connector which is mutually occluded is arranged between the support framework layer and the fusion layer;

3) and (3) programming a printing program: importing the STL file of the prosthesis model into 3D printing equipment, carrying out slicing processing to obtain a current cross-sectional graph to be printed, and designing a plane printing path according to the cross-sectional graph;

4) preparation of printing toner: after the supporting framework layer material and the fusion layer material are respectively subjected to particle proportioning, the supporting framework layer material and the fusion layer material are respectively filled into two mutually independent powdered ink storage areas and are communicated with a powdered ink nozzle through two mutually independent conveying systems;

5) pre-preparation: printing the fusion layer in the first layer along a printing path in an argon atmosphere, heating and melting the fusion layer by using laser or electron beams and solidifying the fusion layer, printing the support skeleton layer in the first layer along the printing path, and heating and solidifying the support skeleton layer by using laser to ensure that the support skeleton layer is fused on the fusion layer to form a first solidification layer; then, continuously laminating a second bonding layer and a third bonding layer on the basis of the first bonding layer until a prosthesis is formed;

6) and (3) detection: after the prosthesis is completely cooled, measuring the size of each key part, comparing the measured size with the three-dimensional mathematical model, and determining the deformation proportion;

7) adjusting the prosthesis model: adjusting the prosthesis model according to the deformation proportion;

8) and (3) reproducing: reprinting according to the adjusted prosthesis model;

9) and (3) detecting again: correcting the deformation proportion;

10) repeat 5) -9) until the deformation ratio is 1, stop the trial printing:

11) preparation: repeating 5) printing the prosthesis layer by layer; starting a heat preservation device in the printing table to keep the temperature of the contact surface of the printing table and the prosthesis consistent;

12) cooling: after printing is finished, rotating the printing table to perform air cooling;

13) and after the temperature reduction is finished, taking down the prosthesis and finishing the printing.

Furthermore, a plurality of stress relief convex hulls which protrude outwards are arranged on the prosthesis model, and the stress relief convex hulls are uniformly arranged on the peripheral circumference of the contact surface of the prosthesis model and the printing table.

Further, the support framework layer is of a hollow titanium structure.

Further, the fusion layer is porous tantalum, and the thickness of the porous tantalum is 1.5-3 mm, the pore diameter is 0.3-0.9 mm, the filament diameter is 0.3-0.6 mm, and the porosity is 75% -85%.

Further, the particle proportioning includes vibration separation and particle remixing processes.

Further, the toner is conveyed by a mixed manner of vibration separation and blade conveyance.

The invention has the beneficial effects that:

1. according to the invention, through the gradient structure of the support framework layer and the fusion layer, the structural strength of the fusion layer can be ensured to realize the functionality of the fusion layer, and the bonding strength of the fusion layer and the natural bone can be increased through the bonding between the fusion layer and the natural bone, so that the fusion layer is fixed stably and reliably. In addition, the gradient design is easy to realize the purposes of saving cost and reducing weight through the selection of materials, for example, the supporting framework layer can consider some materials with high strength, light weight and low price, such as titanium materials, and the fusion layer can consider some materials with good affinity and favorable for bone ingrowth, such as tantalum materials. Thus, the bonding strength is ensured, the weight and the cost are reduced, and the bone prosthesis is helpful for promoting the clinical application of the bone prosthesis.

2. By independently preparing the supporting framework layer and the fusion layer in the same layer, the full melting and combination can be carried out, thereby avoiding the problems of no melting and mutual non-combination caused by different melting temperatures of the supporting framework layer and the fusion layer.

3. Through the particle proportion, adjust the proportion of large granule and tiny particle in the material, strengthened material fluidity on the one hand, on the other hand can ensure the melting level of material, improves the melting efficiency and the consolidation level of material.

4. Through the heat preservation operation, can make the holistic temperature of false body keep in certain extent, avoid the too big defect such as warpage, shrinkage porosity that produces of local section difference in temperature.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a schematic structural view of a prosthesis model;

FIG. 3 is another schematic view of a prosthesis model;

FIG. 4 is a schematic structural view of a prosthesis model without a selenium layer;

FIG. 5 is another schematic view of a prosthesis model without a selenium layer;

FIG. 6 is a schematic view of the structure of a support skeleton layer;

FIG. 7 is a schematic diagram of a printing station according to the present invention;

FIG. 8 is a schematic view of another printing station according to the present invention;

FIG. 9 is a cross-sectional view along the wall thickness of the prosthesis model;

FIG. 10 is an ostomy spacer prosthesis;

FIG. 11 is an acetabular spacer prosthesis;

FIG. 12 is an integrated acetabular cup prosthesis;

FIG. 13 is a 100% total patellar prosthesis;

FIG. 14 is a 100% fibula tumor replacement prosthesis;

FIG. 15 is a 96% fibula tumor replacement prosthesis;

FIG. 16 is a 100% partial patella (patellar housing left) replacement prosthesis;

FIG. 17 is a 100% patellar replacement prosthesis;

FIG. 18 is a 100% pelvic tumor replacement prosthesis;

FIG. 19 is a 100% iliac tumor replacement prosthesis;

FIG. 20 is a 100% knee fusion replacement prosthesis;

FIG. 21 is a femoral side prosthesis;

fig. 22 is a radial bone side prosthesis.

Description of reference numerals:

1-a prosthesis model; 2-supporting a skeleton layer; 3-a fusion layer; 4-a printing table; 5-resistance wire; 6-heating equipment; 7-a rotating electrical machine; 8-stress relief convex hull; 9-linker.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the above description of the present invention, it should be noted that the terms "one side", "the other side" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or the element to which the present invention is directed must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

Further, the term "identical" and the like do not mean that the components are absolutely required to be identical, but may have slight differences. The term "perpendicular" merely means that the positional relationship between the components is more perpendicular than "parallel", and does not mean that the structure must be perfectly perpendicular, but may be slightly inclined.

The invention provides a 3D printing method of a bone defect prosthesis, which comprises the following steps as shown in figure 1:

1) establishing a bone defect model: constructing a three-dimensional mathematical model of the bone defect by utilizing a CT scanning or MRI nuclear magnetic resonance mode;

2) establishing a prosthesis model: constructing a prosthesis model 1 according to a three-dimensional mathematical model, wherein the prosthesis model is a multi-layer composite structure as shown in fig. 2, the composite structure is at least two layers, the inner layer is a support skeleton layer 2 and the outer layer is a fusion layer 3, and a connector 9 which is mutually occluded is arranged between the support skeleton layer and the fusion layer as shown in fig. 6 and 9, the connector is a convex hull which is mutually clamped as shown in fig. 9, and can be of various tooth shapes, so that the joint area between the two can be increased to increase the binding force;

3) and (3) programming a printing program: compiling a printing program according to the prosthesis model;

4) preparation of printing toner:

firstly, preparing a supporting framework layer material: loading a proper amount of supporting framework layer materials into a proportioning mechanism, separating large and small particles, mixing and stirring the large and small particles according to a certain proportion to form mixed powder with moderate large and small particles, and placing the mixed powder in a supporting framework layer material storage area for later use;

preparing a fusion layer material: a proper amount of the fusion layer material is loaded into a proportioning mechanism, the large and small particles are separated firstly, then the large and small particles are mixed according to a certain proportion and stirred to form mixed powder with proper size particles, and the mixed powder is placed in a fusion layer material storage area for standby;

the support framework layer material storage area and the fusion layer material storage area are box bodies which are mutually isolated or independently arranged.

5) Trial preparation:

when the melting point of the fusion layer is higher than that of the support framework layer, the fusion layer in the first layer is printed in advance along the printing path in the argon atmosphere, then the fusion layer is melted and solidified by laser heating, the support framework layer in the first layer is printed in advance along the printing path, and finally the support framework layer is heated and solidified by laser, so that the support framework layer is fused on the fusion layer to form a first solidified layer; then, continuously laminating a second bonding layer and a third bonding layer on the basis of the first bonding layer until a prosthesis is formed;

because the melting point of the fusion layer is higher than that of the support framework layer, the support framework layer cannot be burnt excessively when being heated and melted, and the performance and the combination level of the support framework layer and the support framework layer cannot be influenced.

On the contrary, when the melting point of the support skeleton layer is higher than that of the fusion layer, the support skeleton layer should be printed firstly.

8) and (3) reproducing: reprinting according to the adjusted prosthesis model;

9) and (3) detecting again: correcting the deformation proportion;

10) repeat 5), 6), 7), 8) and 9) until the deformation ratio is 1, i.e. the printed prosthesis is completely identical to the three-dimensional model, at which point the trial printing is stopped:

11) printing: repeating the step 5), and printing the prosthesis layer by layer; starting a heat preservation device in the printing table, wherein the heat preservation device can be a resistance wire 5 arranged in the printing table, and heating the printing table through the resistance wire to keep the temperature of the contact surface of the prosthesis and the temperature of the prosthesis consistent, so that the prosthesis can be always kept in a constant temperature range, and the defects of stress deformation or material tearing and the like caused by overlarge local temperature difference are avoided;

of course, the peripheral space of the printing table may also be heated by the heating device 6 to maintain the peripheral space as a whole in a certain temperature range, as shown in fig. 8.

12) Cooling: after printing is finished, the printing table is driven to rotate through the rotating motor 7, air cooling is carried out, the prosthesis can be cooled integrally through air cooling, the cooling is uniform, the temperature difference is small, the internal stress is small, the deformation is small, and the size of the prosthesis is easy to maintain;

In the invention, a plurality of stress relief convex hulls 8 which are convex outwards are arranged on the prosthesis model, and the plurality of stress relief convex hulls are uniformly printed on the peripheral circumference of the contact surface of the prosthesis model and the printing table. The convex hulls are convex outwards and distributed on the peripheral circumference of the prosthesis model, so that the strength of the peripheral structure can be increased, and the prestress deformation can be resisted better.

In the invention, the support framework layer is made of titanium material, and titanium has lighter mass, lower price and higher structural strength compared with tantalum, so that the structural strength can be ensured while the quality is reduced, and the support function is realized.

In the invention, the fusion layer is made of tantalum material and has a porous structure. The clinical application proves that the tantalum is an orthopedic implant with ideal biocompatibility, and particularly the porous tantalum has a porous structure and an elastic modulus which meet the growth of interface bones and are close to the good mechanical properties of host bones, so that the porous tantalum structure is adopted as a fusion layer in the embodiment, and the porous tantalum structure is combined with the host bones by utilizing the growth characteristics of the bones to enhance the combination strength with bone ends.

The porous tantalum can reduce the strength of solid tantalum, so that the mechanical property similar to that of human bones is realized, but in practical application, not all pore diameters are suitable, for example, the pore diameter is too large, the structural strength of the porous tantalum can be reduced, and the porous tantalum cannot be matched with the human bones; however, too small a pore diameter is not conducive to the growth of bone cells, affecting the level of binding with human bone, and at the same time, may increase weight and load, so that a suitable pore diameter range is selected.

At the same time, strength is also related to porosity, which has been shown by long-term studies and multiple trials to be: the aperture is 0.3-0.9 mm, the silk diameter is 0.3-0.6 mm, the porosity is 75% -85%, and the cell proliferation capacity is better.

In addition, on the basis of ensuring the functions, in order to further reduce the operation cost and the weight of the prosthesis, the thickness of the porous structure is preferably 1.5-3 mm, so that the human bone and the prosthesis can have enough bonding force, and no excessive waste exists.

In actual printing, the supporting framework layer can be of a solid structure or a hollow structure and is mainly arranged according to requirements. In general, the support skeleton layer may be provided as a hollow structure as long as sufficient structural strength is secured. This may further reduce the weight of the prosthesis and may reduce manufacturing costs.

In the present invention, after step 12 and before step 13, the operation of spraying selenium layer 10 on the surface of the prosthesis is also included, as shown in fig. 2-3. Selenium is a multifunctional life nutrient and is widely applied to cancers, operations, chemoradiotherapy and the like. The selenium layer outside the prosthesis is fully contacted with host bones, so that the essential nutrients of a human body are supplemented, and the bone tumor is inhibited to a certain extent.

The application of the method comprises the following steps:

1. an ostomy spacer, as shown in fig. 10.

And (3) wire diameter: 0.5-0.6 mm, pore diameter: 0.3-0.6 mm, porosity > 75%, length x width x height: 32x46x29 mm;

2. acetabular spacers, as shown in fig. 11.

And (3) wire diameter: 0.5-0.6 mm, pore diameter: 0.4-0.6 mm, porosity > 75%, length x width x height: 43x29x25 mm;

3. an integrated acetabular cup, as shown in fig. 12.

And (3) wire diameter: 0.35mm, pore diameter: 0.65mm, porosity 75%, length x width x height: 45x66x99 mm;

4. the patella, as shown in fig. 13.

And (3) wire diameter: 0.5-0.6 mm, pore diameter: 0.4-0.6 mm, porosity of 75%, length x width x height: 48.85X36.0X 28.58mm.

5. Fibula tumor prosthesis, as shown in fig. 14.

And (3) wire diameter: 0.5-0.6 mm, pore diameter: 0.4-0.6 mm, porosity > 75%, length x width x height: 21x19x131 mm.

6. Femoral tumor prosthesis, as shown in fig. 15.

And (3) wire diameter: 0.35mm, pore diameter: 0.75mm, porosity 85%, length x width x height: 128x58x57mm

7. 100% partial patella replacement (leaving patellar housing) as shown in fig. 16.

And (3) wire diameter: 0.5-0.6 mm, pore diameter: 0.4-0.6 mm, porosity > 75%, length x width x height: 47x48.14x23.44mm

8. 100% (total patella replacement), as shown in fig. 17.

And (3) wire diameter: 0.5-0.6 mm, pore diameter: 0.4-0.6 mm, porosity > 75%, length x width x height: 48.85X36.0X 28.58mm.

9. 100% pelvic tumors, as shown in fig. 18.

And (3) wire diameter: 0.35mm, pore diameter: 0.65mm, porosity 70%, length x width x height: 163x104x61mm

10. 100% iliac tumors, as shown in fig. 19.

And (3) wire diameter: 0.35mm, pore diameter: 0.7-0.9 mm, porosity 85%, length x width x height: 100% of 66x72x74 mm.

11. The knee fusion was 100% as shown in fig. 20.

And (3) wire diameter: 0.5-0.6 mm, pore diameter: 0.4-0.6 mm, porosity of 75%, length x width x height: 65x43x50 m.

12. Femoral side, as shown in fig. 21.

And (3) wire diameter: 0.3-0.4 mm, pore diameter: 0.7-0.8 mm, porosity 75.95%, length x width x height: 67x42x65 mm.

13. The tibial side, as shown in fig. 22.

And (3) wire diameter: 0.35mm, pore diameter: 0.7-0.8 mm, porosity 75%, length x width x height: 68x60x43 mm.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims

1. A3D printing method of a bone defect prosthesis is characterized by comprising the following steps: the method comprises the following steps:

5) pre-preparation: printing the fusion layer in the first layer along a printing path in an argon atmosphere, heating and melting the fusion layer by using laser or electron beams and solidifying the fusion layer, printing the support skeleton layer in the first layer along the printing path, and heating and solidifying the support skeleton layer by using laser to ensure that the support skeleton layer is fused on the fusion layer to form a first solidification layer; then, repeating the step 5) on the basis of the first bonding layer, and continuously laminating the second bonding layer and the third bonding layer until the prosthesis is formed;

8) and (3) reproducing: repeating the steps 3) -5) according to the adjusted prosthesis model until the prosthesis is formed;

9) and (3) detecting again: repeating the step 6), and correcting the deformation proportion;

10) repeating the steps 5) -9) until the deformation ratio is 1, and stopping the trial printing:

11) preparation: repeating the step 5) to prepare the prosthesis layer by layer; starting a heat preservation device in the printing table to ensure that the temperature of the contact surface of the heat preservation device and the prosthesis is consistent with that of the prosthesis;

2. The 3D printing method of a bone defect prosthesis according to claim 1, wherein: the prosthesis model is provided with a plurality of stress relief convex hulls which protrude outwards, and the stress relief convex hulls are uniformly arranged on the peripheral circumference of the contact surface of the prosthesis model and the printing table.

3. The 3D printing method of a bone defect prosthesis according to claim 1, wherein: the support framework layer is of a hollow titanium structure.

4. The 3D printing method of a bone defect prosthesis according to claim 1, wherein: the fusion layer is porous tantalum, the thickness range of the porous tantalum is 0.4-0.6 mm, the pore diameter range is 0.3-0.9 mm, the filament diameter range is 0.3-0.6 mm, and the porosity range is 75% -85%.

5. The 3D printing method of a bone defect prosthesis according to claim 1, wherein: the particle proportioning comprises vibration separation and particle remixing processes.

6. The 3D printing method of a bone defect prosthesis according to claim 1, wherein: the conveying system conveys the toner in a mixed mode of vibration separation and blade conveying.