CN104251796A - Ball socket sample for simulating artificial intervertebral disc and preparation method and application of ball socket sample - Google Patents

Abstract

The invention discloses a ball-socket sample for simulating an artificial intervertebral disc. The ball-socket sample includes a ball head and a ball socket matched with the ball head. The ball head and the ball socket are in surface-to-surface contact. The invention also discloses the preparation method of the simulated artificial intervertebral disc ball-socket sample and its application in simulating and testing the biotribological properties of the artificial intervertebral disc. The ball-and-socket sample of the present invention can be closer to the actual artificial intervertebral disc in terms of contact mode, matching materials, and motion mode, and has the advantages of simple operation, high cost performance, wide application range, and easy evaluation of prosthesis design, manufacture, and comprehensive performance.

Description

A simulated artificial disc ball-socket sample and its preparation method and application

technical field

The invention relates to the field of biotribological performance testing of artificial intervertebral discs, in particular to a simulated artificial intervertebral disc ball-socket sample, a preparation method of the sample and an application in biotribological performance of artificial intervertebral discs.

Background technique

Compared with traditional spinal fusion, cervical or lumbar disc replacement (TDR) has the advantages of maintaining the normal range of motion and stability of adjacent segments, improving the pressure in adjacent intervertebral spaces, reducing the incidence of new disease in adjacent segments, and reducing postoperative It is considered to be the most promising spinal biomechanical reconstruction technique due to its advantages of fixed time and allowing patients to return to normal life as soon as possible. However, before the artificial intervertebral disc enters the clinic, it must first pass the systematic in vitro biotribological performance and wear life prediction evaluation, which is a complex and critical process. At present, the main preclinical evaluation methods include conventional tribological testing machine method, finite element method, spine simulation testing machine method and animal experiment method.

Among them, the finite element method is more used in the biomechanical evaluation of prostheses, and it has only been gradually applied to the field of wear performance research in recent years, and its reliability needs to be further verified; conventional tribological testing machine methods generally use pin/ball-disk pairings, Focus on the wear resistance, corrosion resistance, surface activity and coating binding ability of articular surface materials. The test environment is relatively simple, and it is not easy to reproduce the actual physiological and mechanical environment of the prosthesis for a long time (body fluid environment, flexion, side bending, rotation compound physiological movement) ); the animal experiment method is also limited to the comprehensive detection of the prosthesis before it enters the clinic due to the time-consuming, complicated operation, and the fact that the motion pattern of the human spine is not exactly the same; The special equipment developed for the tribological performance has become the main method for the design and manufacture of artificial intervertebral discs and the medium and long-term biological tribological performance, especially the wear performance evaluation, but it also has the disadvantages of high cost, complicated prosthesis installation operation, and long cycle. Therefore, in the field of biotribological performance and wear life prediction and evaluation of artificial intervertebral discs and artificial joints, there is an urgent need for a test scheme that is simple to operate, cost-effective, wide in application, and can easily evaluate the design, manufacture and comprehensive performance of prostheses.

Since most of the existing artificial cervical/lumbar intervertebral discs at home and abroad are based on the design of the ball-socket (socket) joint structure, taking the Discover cervical intervertebral disc as an example, the ultra-high molecular weight polyethylene (UHMWPE) nucleus pulposus is fixed on the lower endplate, and the upper endplate It is a highly polished concave surface that articulates with the nucleus pulposus. In view of the fact that the motion design of the artificial intervertebral disc is mainly on the ball-and-socket joint surface, and the ball-socket joint surface is also a key area most prone to failure modes such as wear and abrasion. Therefore, if we can be inspired by this, and combine the current situation of artificial intervertebral discs and artificial joints with biotribological performance and wear life prediction and evaluation needs, we can develop a new test scheme for evaluating the tribological performance of prostheses, which will definitely improve the prosthesis. It plays a huge role in promoting and promoting research and development.

Contents of the invention

The object of the present invention is to address the deficiencies of the prior art, and propose a simulated artificial intervertebral disc ball-socket sample with simple structure, high cost performance, wide application range, and easy evaluation of prosthesis design.

The invention discloses a ball-socket sample for simulating an artificial intervertebral disc. The ball-socket sample includes a ball head and a ball socket matched with the ball head. The ball head and the ball socket are in surface-to-surface contact.

The surface-to-surface contact is through the matching contact between the protrusion at one end of the ball head and the groove of the ball socket.

The contact surface between the protrusion at one end of the ball head and the groove of the ball socket is a spherical or ellipsoidal spherical crown surface.

The convex surface at one end of the ball head is greater than or equal to the groove surface of the ball socket.

The other end of the ball head is a cylinder, a cuboid, a cube or other geometric shapes, the ball socket is a cylinder, a cuboid, a cube or other geometric shapes, and the groove of the ball socket is arranged inside one end surface of the ball socket.

The materials of the ball head and the ball socket can be both polymers, medical titanium alloys, polymers and medical titanium alloys or medical titanium alloys and polymers respectively.

The polymer may be polyether ether ketone or ultra high molecular weight polyethylene or nanoparticle filled ultra high molecular weight polyethylene. Among them, the molecular weight of ultra-high molecular weight polyethylene is between 1 million and 6 million. The nanoparticles can be inorganic nanoparticles or metal nanoparticles or ceramic (such as zirconia, alumina, etc.) nanoparticles.

The invention also discloses a method for preparing the ball-socket sample of the simulated artificial intervertebral disc. When the ball head and/or the ball-socket are polymer materials, the polymer powder is put into a special ball-head and/or ball-socket mould. , The hot pressing molding of the powder is completed on the hot pressing equipment through the process of heating, heat preservation and cooling.

It is also possible to mix ultra-high molecular weight polyethylene powder with a particle diameter of 30 μm to 300 μm and nano-filled particles with a particle diameter of 50 nm to 500 nm (the filling amount is 0-15 wt% of the polyethylene powder) and put them into a special mold evenly. The hot pressing molding of the powder is completed through the process of heating, heat preservation and cooling on the hot pressing equipment.

The temperature rise is in a low vacuum environment, the pressure is 2-40MPa, and the temperature is raised to 160-220°C; the holding time is 90-150 minutes; the temperature drop is in a low vacuum environment, the pressure is 6-40MPa, and natural cooling is performed.

When the ball head and/or ball socket are made of titanium alloy, they can be produced together by machining.

The invention also discloses the application of the ball-socket sample of the simulated artificial intervertebral disc in simulating and testing the biotribological performance of the artificial intervertebral disc.

The beneficial effects of the present invention are:

(1) Compared with the general tribological experiment method of ball/pin-disk pair, the ball-and-socket pair can be closer to the actual artificial intervertebral disc in terms of contact mode, mating material, and motion mode. and comprehensive performance; at the same time, the solution of the present invention has the advantages of simple operation, high cost performance, wide application range, and easy evaluation of prosthesis design, manufacture and comprehensive performance.

(2) The preparation method of the simulated artificial intervertebral disc ball-socket sample disclosed by the present invention can be directly applied to the corresponding tribology testing machine, and solves the problem that the polymer spherical structure is not easy to be machined.

(3) The ball-and-socket sample of the present invention is installed on a tribological testing machine, which can independently realize twisting (rotation), swinging, buckling, side bending and compound motion, so as to evaluate motion mode, material matching, prosthesis design, and test The influence of parameters on the tribological properties of ball and socket samples, and the prediction of wear life and comprehensive performance of prostheses.

Description of drawings

FIG. 1 is a schematic diagram of the structure of a ball and socket sample in Example 1.

Detailed ways

The present invention will be further elaborated below through specific embodiments in conjunction with the accompanying drawings.

Example 1:

The structure schematic diagram of the simulated artificial intervertebral disc ball-socket sample of the present invention is as shown in Figure 1. It is composed of a ball head 10 and a ball socket 20. One end 11 of the ball head 10 is a cylinder or a cube or a cuboid or other geometric structures. The protrusion 12 at the other end of the ball head 10 is spherical or ellipsoidal, and the ball socket 20 is a cylinder or a cube or a cuboid or other geometric structures, and a groove 21 is provided on one end surface of the ball socket 20. The shape of the groove 21 and the protrusion 12 are matched, and the ball head 10 and the ball socket 20 are in surface-to-surface contact through the protrusion 12 and the groove 21, and the contact surface is a spherical or ellipsoidal spherical crown surface.

In the present embodiment, the contact surface of the ball-and-socket structure design adopts a spherical spherical crown surface contact, selects a very small enveloping depth (1.5mm), and the protrusion 12 of the ball head 10 is spherical, and its radius is 13mm. One end 11 of the head 10 is cylindrical, with a diameter of 22 mm and a height of 13 mm. The ball socket 20 is designed as a cylindrical structure with a diameter of 30 mm and a height of 5 mm, which can be closely connected with the upper and lower fixtures of the testing machine.

Example 2:

Stir the ultra-high molecular weight polyethylene powder with a particle diameter of 150 μm and zirconia nano-filled particles with a particle diameter of 150 nm (the filling amount is 5 wt%) and put them into a special mold, and heat up, keep warm and cool down on the hot pressing equipment The process completes the hot pressing of the powder. The temperature rise is in a low vacuum environment, the pressure is 10MPa, and the temperature is raised to 200°C; the holding time is 100 minutes; the temperature drop is in a low vacuum environment, the pressure is 20MPa, and natural cooling is performed to obtain the ball head and the ball socket.

Example 3:

Stir the ultra-high molecular weight polyethylene powder with a particle diameter of 200μm and zirconia nano-filled particles with a particle diameter of 300nm (filling amount is 10wt%) and put them into a special mold. The process completes the hot pressing of the powder. The temperature rise is in a low vacuum environment, the pressure is 30MPa, and the temperature is raised to 160°C; the holding time is 90 minutes; the temperature drop is in a low vacuum environment, the pressure is 30MPa, and natural cooling is performed to obtain the ball head and the ball socket.

Example 4:

The simulated artificial intervertebral disc ball-socket sample prepared in Example 1 was used to simulate and test the biotribological properties of the artificial intervertebral disc.

The ball head 10 and the ball socket 20 paired sample are installed on a tribological testing machine, and are respectively moved according to torsion (rotation), swing, buckling, side bending and compound motion modes, so as to evaluate the motion mode, material pairing, The impact of prosthesis size design and test parameters on the tribological properties of ball and socket samples, and the prediction of the wear life and comprehensive performance of the prosthesis.

In summary, although the specific embodiments of the present invention have described the present invention in detail, those of ordinary skill in the art should understand that the above-mentioned embodiments are only descriptions of preferred embodiments of the present invention, rather than protection scope of the present invention. Any changes that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention are within the protection scope of the present invention.

Claims (10)

1. simulate an artificial intervertebral disk ball-and-socket sample, it is characterized in that: described ball-and-socket sample comprises bulb and joins secondary ball-and-socket with bulb, and bulb and ball-and-socket are that face-face contacts.

2. simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 1, is characterized in that: the contact of described-face to be matched each other with the groove of ball-and-socket by the projection of bulb one end to contact.

3. simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 2, is characterized in that: between the projection of described bulb one end and the groove of ball-and-socket, surface of contact is the spherical crown surface of spheroidal or elliposoidal.

4. simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 2, is characterized in that: the crowning of described bulb one end is more than or equal to the groove surface of ball-and-socket.

5. simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 1, it is characterized in that: the other end of described bulb is right cylinder, rectangular parallelepiped, square or other geometric configuratioies, described ball-and-socket is right cylinder, rectangular parallelepiped, square or other geometric configuratioies, and the groove of described ball-and-socket is arranged on ball-and-socket one end face inside.

6. simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 1, is characterized in that: described bulb and ball-and-socket material are polymkeric substance or are medical titanium alloy or are respectively polymkeric substance and titanium alloy or are respectively titanium alloy and polymkeric substance.

7. simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 6, is characterized in that: described polymkeric substance is the ultra-high molecular weight polyethylene of polyetheretherketone or ultra-high molecular weight polyethylene or nano particle filling.

8. the preparation method of simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 6, it is characterized in that: when described bulb and/or ball-and-socket are polymeric material, polymer powder is put into special bulb and/or ball-and-socket mould, hot-press equipment completes the hot-forming of powder by intensification, insulation and temperature-fall period.

9. the preparation method of simulation artificial intervertebral disk ball-and-socket sample as claimed in claim 8, is characterized in that: described intensification is in low vacuum environment, and pressure is 2-40MPa, is warming up to 160-220 DEG C; Temperature retention time is 90-150 minute; Described cooling is in low vacuum environment, and pressure 6-40MPa carries out nature cooling.

10. utilize the application of simulation artificial intervertebral disk ball-and-socket sample in simulation test artificial intervertebral disk bio-tribology performance described in claim 1.