CN111631842A

CN111631842A - Method for preparing bone defect prosthesis

Info

Publication number: CN111631842A
Application number: CN202010517433.XA
Authority: CN
Inventors: 王富友; 杨柳; 范华全; 何鹏; 李倩
Original assignee: First Affiliated Hospital of PLA Military Medical University
Current assignee: First Affiliated Hospital of PLA Military Medical University
Priority date: 2020-06-09
Filing date: 2020-06-09
Publication date: 2020-09-08
Anticipated expiration: 2040-06-09
Also published as: CN111631842B

Abstract

The invention relates to a method for preparing a bone defect prosthesis, which belongs to the technical field of bone prosthesis manufacture, and 1) a prosthesis model is established: adopting nuclear magnetic resonance or CT to scan the bone defect part to construct a bone prosthesis model: 2) establishing a fusion area: modifying the region of the bone prosthesis model, which is attached to the human bone defect part, into a fusion region with a porous structure; 3) compiling a printing program; 4) preparing for printing; 5) printing: printing a first layer along the printing path, melting by laser heating or melting and solidifying by electron beams, and then continuously laminating a second layer and a third layer until a TC4 matrix is formed; 6) spraying: and depositing the micron-sized Ta powder into the porous structure of the fusion area through vapor deposition, cold spraying or plasma spraying to obtain the bone defect prosthesis. The method can quickly and accurately prepare the titanium alloy matrix and the bioactive layer, and solves the problems of long preparation time and high preparation cost in the prior art while improving the fusion level.

Description

Method for preparing bone defect prosthesis

Technical Field

The invention relates to the technical field of bone prosthesis manufacturing, in particular to a method for preparing a bone defect prosthesis.

Background

Bone deficiency due to disease, trauma or surgery is called bone defect. For severe bone defects, bone prostheses are required to fill and repair, so that the bone is intact and the motor function is restored. In the prior art, a Ti6Al4V (TC4) titanium alloy material is often adopted to prepare the bone prosthesis, and the binding force between the bone prosthesis and the defect part of the human body is insufficient due to insufficient affinity with the human body, so that the motor function of the bone prosthesis can not be repaired.

Tantalum is an extremely desirable biocompatible material. It can be directly contacted with human skeleton, muscle tissue and liquid, and can be adapted to biological cell, and has excellent affinity, and hardly produces irritation and side effect to human body. In the prior art, it has been proposed to prepare a porous tantalum coating on a Ti6Al4V (TC4) titanium alloy substrate to improve its viability in human bone repair surgery.

While tantalum exhibits good biological properties, it is also limited by its extremely challenging manufacturing process. Currently, methods for preparing tantalum coatings mainly include plasma spraying (APS) and high-velocity oxygen flame spraying (HVOF), but the tantalum coatings prepared by these methods have high oxygen content due to high temperature, and need to be operated in a vacuum chamber or a high-purity protective atmosphere, which results in high preparation cost. Meanwhile, these methods have problems such as uneven pores, irregular pore shapes, and too few through holes, which affect the bone ingrowth effect.

In order to solve the above problems, the prior art proposes a method for cold spraying a porous coating, wherein another phase (Al) which is easy to remove and has good plasticity is added into Ta powder as a pore-forming agent, and then a chemical oxidation method is used to remove the Al, thereby forming a porous tantalum structure.

Although the method can form a porous tantalum structure, the oxidation reaction time is 1-7 days, the preparation efficiency is seriously delayed, and the method is a test for severe patients; meanwhile, in the scheme, a porous structure is obtained by adopting a soaking reaction and a coating is sprayed, but both the two processes cannot accurately operate a certain specified region of the bone prosthesis, so that the coating area needs to be increased to make up for the defects, and the workload and the preparation cost are increased; in addition, in the above solution, no solution is provided for the obtainment of Ti6Al4V (TC4) titanium alloy matrix, possibly increasing the risk of uncertainty.

Disclosure of Invention

In view of the above, the present invention provides a method for preparing a bone defect prosthesis, which can rapidly and accurately prepare a titanium alloy substrate and a bioactive layer, and solve the problems of long preparation time and high preparation cost in the prior art.

The invention is realized by the following technical scheme:

a method of making a bone defect prosthesis comprising the steps of:

1) establishing a prosthesis model: adopting nuclear magnetic resonance or CT to scan the bone defect part to construct a bone prosthesis model;

2) establishing a fusion area: modifying the region of the bone prosthesis model, which is attached to the human bone defect part, into a fusion region with a porous structure;

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

4) printing preparation: uniformly mixing Ti6Al4V titanium alloy powder according to a particle ratio, filling the mixture into a material storage area, and communicating the material storage area with a material spray head;

5) printing: printing a first layer along the printing path, melting by laser heating or melting and solidifying by electron beams, and then continuously laminating a second layer and a third layer until a TC4 matrix is formed;

6) spraying: and depositing the micron-sized Ta powder into the porous structure of the fusion area through vapor deposition, cold spraying or plasma spraying to obtain the bone defect prosthesis.

Furthermore, the granularity range of the Ta powder is 10-60 mu m.

Further, the thickness of the fusion area of the bone defect prosthesis is 6000 μm and the pore diameter is 600 μm and 75% -85%.

Further, in the step 6), multi-angle omnibearing spraying is carried out on the fusion layer.

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

Further, the TC4 matrix is internally provided with a hole-shaped weight-reducing structure.

The invention has the beneficial effects that:

1. according to the invention, a bone defect model is obtained through CT or nuclear magnetic resonance, and then a TC4 matrix is prepared through 3D printing, so that the matching level of the bone defect model and the human body defect is obviously improved through personalized customization, and the fusion with the human body bone is facilitated;

2. the method directly prints out the fusion area of the porous structure, the material of the fusion area is consistent with that of the matrix, and Ta powder is solidified on the porous structure by using vapor deposition or cold spraying or plasma spraying technology to directly obtain the bioactive layer, so that the efficiency is high, and the preparation cost is low;

in a word, the invention can rapidly and accurately prepare the titanium alloy matrix and the bioactive layer, and solves the problems of long preparation time and high preparation cost in the prior art while improving the fusion level.

Drawings

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

FIG. 2 is a schematic view of a femoral defect;

FIG. 3 is another schematic view of a femoral defect;

FIG. 4 is a schematic structural view of a bone prosthesis model;

FIG. 5 is a top view of a bone prosthesis model;

FIG. 6 is a front view of the bone prosthesis;

fig. 7 is a cross-sectional view of a bone prosthesis.

Description of reference numerals:

1-femur; 2-defect site; 3-a bone prosthesis model; 4-boundary line; 5-a fusion region; 6-a bone prosthesis; 7-TC4 matrix; 8-maximum profile line.

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 present invention provides a method for preparing a bone defect prosthesis, as shown in fig. 1, comprising the steps of:

1) establishing a prosthesis model: as shown in fig. 2, a femur defect map is shown, a defect part 2 is arranged on a femur 1, the bone defect part is cleaned and cleaned to be clearly visible, and a CT scanner is used for scanning and imaging or nuclear magnetic resonance imaging is used for constructing a three-dimensional mathematical model of the bone defect; then constructing a bone defect bone prosthesis model 3 through a three-dimensional mathematical model of the bone defect, as shown in figure 3;

2) establishing a fusion region, specifically comprising the following steps:

determining a boundary: the boundary line 4 of the human body bone defect part wrapping the bone prosthesis is taken as a boundary; of course, if the boundary line is also the maximum contour line 8 of the bone prosthesis, the fusion area may also be slightly smaller than the boundary line, which is the case in this embodiment, as shown in fig. 4;

and (3) porous treatment: and adopting UG crystal lattice instructions to generate a porous structure with the mesh size of 400-700 mu m, the thickness of 1000-6000 mu m and the porosity of 80-90% in the area defined by the boundary, wherein the area where the porous structure is located is the fusion area 5.

4) printing preparation: loading Ti6Al4V titanium alloy powder into a proportioning mechanism, separating large and small particles, mixing and stirring the large and small particles according to a certain proportion to form a mixed material with moderate large and small particles;

5) printing: printing the mixed material into a first layer along a printing path by using 3D printing equipment, heating and melting by using laser, solidifying, and then continuously laminating a second layer and a third layer until a TC4 matrix 7 is formed;

in actual printing, in order to reduce weight, on the premise of ensuring the structural strength of the TC4 matrix, the TC4 matrix is not a complete solid structure, and a plurality of weight reduction holes are arranged in the TC4 matrix, so that the weight and the manufacturing cost of the prosthesis can be effectively reduced;

6) cold spraying: and (3) spraying and depositing micron-sized Ta powder on the surface of the fusion area under a certain condition by adopting cold air power spraying equipment to form a continuous Ta coating to wrap the titanium alloy matrix, so as to form a bioactive layer to prepare the bone defect prosthesis 6, as shown in figures 6 and 7.

The working conditions of the cold spraying equipment are that the temperature is 400-500 ℃, the pressure is 2.5-3.5 MPa, the spraying distance is 15-25 mm, and compressed air is selected as a spraying medium.

The Ta powder is basically spherical or quasi-spherical, the particle size range is 10-60 μm, and ideally, the thickness of the prepared fusion region is 6000 μm plus 1000-.

In step 5), electron beam melting may also be used for melting.

The molding of the TC4 substrate may be achieved by extrusion molding. Based on the TC4 matrix with structural strength finally obtained.

The cold air power spraying equipment used in the step 6) can be various existing equipment, but the spray head is selected to be movable, and the axis of the spray head is changeable, so that the change of the included angle between the spray head and the fusion area is realized, the fusion layer is sprayed in a multi-angle and all-dimensional mode, and the chance that Ta powder and porous wire meet and increase the bonding rate is improved as much as possible. In this step, the Ta powder may be deposited into the porous structure of the fusion region by vapor deposition or plasma spraying. Although plasma spraying also needs high-purity gas shielding, the plasma spraying only sprays on the surface of the mesh, so that the spraying amount is small compared with that of the integrally prepared fusion layer, and the preparation time is short. Of course, when the system is used specifically, the selection can be carried out according to actual needs so as to meet individual requirements.

Of course, a nozzle fixing jig may be made, and a corresponding rotation function member may be provided to the jig so that the nozzle is movable and rotatable with respect to the fusion surface, thereby achieving the function.

In the embodiment, the bone defect model is obtained through CT or nuclear magnetic resonance, and then the TC4 matrix is prepared through 3D printing, so that the matching level of the bone defect model and the human body defect is obviously improved through personalized customization, and the fusion with the human body bone is facilitated;

in the embodiment, the fusion area of the porous structure is directly printed, the material and the matrix of the fusion area are both titanium alloy, Ta powder is solidified on the porous structure by using a cold spraying technology, a vapor deposition technology or a plasma spraying technology, and a bioactive layer is directly obtained; in addition, the scheme only adopts the tantalum coating, so that the using amount of the tantalum material can be effectively reduced, the weight of the bone prosthesis is reduced, and the preparation cost is further reduced.

In the embodiment, the proportion of large particles to small particles in the material is adjusted through the particle proportion, so that the flowability of the material is enhanced, the melting level of the material can be ensured, and the melting efficiency and the consolidation level of the material are improved.

In a word, compared with the prior art, the preparation method of the embodiment can be used for quickly and simply preparing while enhancing biocompatibility and osseointegration, shortening the preparation period, reducing material consumption and preparation cost, and solving the problems of long preparation time and high preparation cost in the prior art.

The present embodiment is exemplified by a femur, and is not limited to a femur, and is also applicable to any portion having a bone defect.

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. A method of making a bone defect prosthesis, comprising: the method comprises the following steps:

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

2. A method of preparing a bone defect prosthesis according to claim 1, wherein: the granularity range of the Ta powder is 10-60 mu m.

3. A method of preparing a bone defect prosthesis according to claim 1, wherein: the thickness of the fusion area of the bone defect prosthesis is 1000-6000 mu m, the pore diameter is 300-600 mu m, and the porosity is 75-85%.

4. A method of preparing a bone defect prosthesis according to claim 1, wherein: and 6), performing multi-angle omnibearing spraying on the fusion layer.

5. A method of preparing a bone defect prosthesis according to claim 1, wherein: the particle proportioning includes a vibration separation and particle remixing process.

6. A method of preparing a bone defect prosthesis according to claim 1, wherein: the TC4 matrix is internally provided with a hole-shaped weight-reducing structure.