CN107569306B - Spinal implant - Google Patents

Abstract

A spinal column implant is prepared by porous material, the spinal column implant includes straight front end, convex back end, two ends extending between the front end and the back end, middle convex arched upper surface, flat lower surface, a through hole between the upper surface and the lower surface, a through hole at the back end, extending from the back end to the through hole between the upper surface and the lower surface, the porous material is multi-stage hole material with multi-stage holes cavity grading according to the aperture size of the material, each stage hole cavity is communicated with each other and the holes cavities are communicated with each other, the porosity of the minimum stage hole part material of the multi-stage hole material is not less than 50%, the upper surface and the lower surface are both provided with holes, the spinal column implant is helpful for the spinal column implant to bear more drugs such as bone growth factors, the fusion of the spinal column implant and the surrounding bones is accelerated, the bonding surface of the spinal column implant and the bones is enlarged, so that the spinal implant can be fused with the bone more firmly.

Description

Spinal implant

Technical Field

The invention relates to a prosthesis, in particular a spinal implant.

Background

The reduction of spinal stability caused by degenerative changes of the spine, segmental instability, trauma and the like can cause pain and dyskinesia of limbs, the mild disease can be relieved by non-operative treatment, and patients who do not have the effect of the non-operative treatment and patients with serious symptoms need to be treated by the operation. Anterior decompression of the spine, total or sub-total resection of the vertebral body is considered the primary surgical treatment. During the surgical procedure, the surgeon is required to reconstruct the spine with lost intact stability, and a previously common method is to implant autologous skeletal bone to fill the vertebral body bone defect. However, the simple autologous bone transplantation has disadvantages such as insufficient autologous bone mass and insufficient immediate stability after the operation. Titanium cages and artificial vertebral bodies are increasingly used clinically as effective spinal implants. However, the titanium cages or artificial vertebral bodies used at present are purely mechanical supporting materials, and compared with autologous bones, the titanium cages or artificial vertebral bodies do not have bone conduction, bone induction and osteogenesis effects, and can not promote the fusion of adjacent spinal column segments on the premise of restoring the stability of the spinal column. Later, it was proposed to use porous materials for the spinal implants, such as CN 103961746 a, which describes a biological spinal interbody fusion cage comprising a surface porous structure and an internal three-dimensional porous bone tissue engineering scaffold, wherein the surface porous structure and the internal three-dimensional porous tissue engineering scaffold are interconnected and can be made of metal, ceramic, natural or synthetic polymer materials. US 2008/0200985A 1 describes a spinal implant made of a porous material and including a generally straight anterior end, an outwardly convex posterior end, two ends extending generally between the anterior and posterior ends, a generally medial outwardly convex arcuate upper surface, and a flat lower surface. Such spinal implants help restore spinal stability. The spinal implant body is made of porous materials with single pore, on one hand, the materials can store insufficient medicines such as bone growth factors, and on the other hand, the surface combined with the bone is relatively flat, so that the fusion of the spinal implant body and the surrounding bone is slow and unstable. Zou X et al (Bone in tissue engineering of porous tantalum and carbon fiber in Bone J. 2004, 4(1): 99-105) showed that when an intervertebral cage was made of conventional single pore porous tantalum, tissue sectioning of the novel porous material revealed that Bone tissue often only grew into the outer edges of the pores or surface pores of the porous material and did not fill the pores inside the material.

The invention content is as follows:

the invention aims to provide a spinal implant which can be stably fused with adjacent bone tissues at a high fusion speed so as to stabilize the spinal column.

The inventor considers that the spinal implant can bear more medicaments such as bone growth factors and the like, the structure is improved, and the joint surface with the bone is increased to ensure that the spinal implant is fused and stabilized with the adjacent bone tissue, and for this reason, the inventor proposes the following scheme:

a kind of spinal column implant, it is prepared from porous material, this spinal column implant includes straight anterior extremity, convex rear end, expand both ends extending between anterior extremity and rear end, middle convex arch upper surface, flat lower surface, have a through hole from upper surface to lower surface, can be used for packing the bone graft, there is a through hole in the rear end, extend and link up with the through hole between upper surface to lower surface inwardly from the rear end, used for the operation tool to insert while implanting the operation, the said porous material is the multi-stage pore material, this multi-stage pore material is graded by the material aperture size, and surround and form the cavity wall of each stage of the cavity to form; the cavity wall which surrounds and forms a superior pore cavity in a three-dimensional space is made of a inferior porous material, each level of pore cavity is communicated with each other, each level of pore cavity is also communicated with each other, the porosity of the minimal pore part material of the multilevel pore material is not less than 50%, the porosity only refers to the porosity of the minimal pore part material, namely, the material with the minimal pore is taken during calculation, and the ratio of the porosity of the minimal pore to the taken material is the porosity of the minimal pore part material; the holes on the upper surface and the lower surface help the spinal implant to bear more medicines such as bone growth factors and the like, the fusion of the spinal implant and surrounding bones is accelerated, the combining surfaces of the spinal implant and the bones are enlarged by the holes on the upper surface and the lower surface, and bone tissues growing in the holes can play a role of a bracket, so that the fusion of the spinal implant and the bones is firmer.

Furthermore, the wall of the through hole between the upper surface and the lower surface of the spinal implant is provided with a hole, so that the bone graft filled in the through hole is more firmly fused with the spinal implant.

Furthermore, the holes on the upper surface and the holes on the lower surface or the holes on the wall of the through hole between the upper surface and the lower surface are uniformly distributed, so that the bonding force between the spinal implant and the bone is uniform.

Furthermore, the diameter of the hole of the spinal implant is not less than 2mm, the depth of the hole is 0.4-1 times of the diameter, and the hole with the size enables the spinal implant to be stably fused with bones.

Furthermore, the hole is a taper hole, the large end of the taper hole is arranged on the surface, the diameter of the small end of the taper hole is not less than 2mm, the depth of the hole is 0.4-1 time of the diameter, and the taper hole enables the bonding strength of the spinal implant and the bone to be higher.

Furthermore, when the hierarchical level of the multi-level pore material is three, the aperture of the first-level pore cavity is a micron-level pore, the aperture of the third-level pore cavity is a nanometer-level pore, and the aperture of the second-level pore cavity is between the apertures of the first-level pore cavity and the third-level pore cavity.

Furthermore, the diameter of the maximum primary pore of the multi-level pore material is 100-600 μm, which is beneficial to bone tissue growth.

Furthermore, the porous material of the spinal implant is a porous metal material, a porous non-metal material or a composite material of porous metal and non-metal. The porous metal material comprises medical titanium and alloy, medical niobium and alloy, medical tantalum and alloy, medical stainless steel, medical cobalt-based alloy, medical magnesium and alloy and the like, and the nonmetal comprises medical ceramic, medical polymer and the like.

The invention has the beneficial effects that:

(1) the spinal implant provided by the invention is prepared by adopting the multi-level hole material, the cavity wall of the superior hole is provided with the inferior hole, and particularly, the porosity of the material of the minimum level hole part is not less than 50%, so that the specific surface area of the material is obviously increased, the medicines such as bone growth factors and the like which can be borne by the material are also obviously increased, and the spinal implant is favorable for accelerating the fusion of the spinal implant and the surrounding bone tissues under the continuous action of the medicines such as the bone growth factors and the like after the spinal implant is implanted.

(2) The holes on the upper surface and the lower surface and the holes on the wall of the through hole between the upper surface and the lower surface enlarge the joint surface of the spinal implant and the bone, and the bone tissue grown in the holes can play a role of a bracket, so that the joint of the spinal implant and the bone is firmer.

(3) The spinal implant provided by the invention has the advantages that the three-level pore structure adopted by the porous metal material with the multi-level pore structure is particularly favorable for the fusion with bone tissues after the spinal implant is implanted, the size of the first-level pore cavity is favorable for meeting the requirement of tissue growth, the second-level pore cavity is favorable for inhabitation of various cells, and the third-level pore cavity is favorable for meeting the requirements of cell adhesion and differentiation.

Drawings

The invention will be further elucidated with reference to the embodiments and drawings.

FIG. 1 is a schematic view of a spinal implant in accordance with the present invention;

FIG. 2 is a left side view of FIG. 1;

FIG. 3 is a top view of FIG. 1;

FIG. 4 is a rear view of FIG. 1;

FIG. 5 is a schematic view of a spinal implant according to example 3;

FIG. 6 is a cross-sectional view A-A of FIG. 5;

FIG. 7 is a schematic view of a spinal implant according to example 4;

FIG. 8 is a sectional view B-B of a surface taper hole in example 4;

fig. 9 is a schematic structural diagram of a hierarchical pore material.

Detailed Description

The following description will be made in conjunction with the accompanying drawings, which are provided to explain the embodiments of the present invention in detail and to explain the detailed embodiments and the specific operation procedures based on the technical solutions of the present invention, but the scope of the present invention is not limited to the following embodiments.

As shown, 1 is the front end of the spinal implant, 2 is the spinal implant rear end, 3 is the terminal surface that extends between front end and rear end, 4 is the upper surface of the spinal implant, 5 is the lower surface of the spinal implant, 6 is the through-hole between upper surface to the lower surface, 7 is the through-hole of rear end, 8 is the hole of upper surface, 9 is the hole of lower surface, 10 is the hole on the wall of the through-hole between upper surface to the lower surface, 11 is the taper hole. Fig. 9 shows that the structure of the hierarchical porous material is a secondary porous material, 12 is a large hole, 13 is the wall of the large hole, and 14 is a small hole on thewall 13 of the large hole.

Example 1

The spinal implant is prepared from a porous cobalt-based alloy material CoCrMo with a secondary pore structure, the pore size of a large pore cavity is 100-350 mu m, the pores are communicated with each other, the pore size of a small pore on the wall of the large pore cavity is 400-650 nm, the small pores are also communicated with each other, the large pore and the small pore are also communicated with each other, the porosity of the small pore is 50%, the diameters of the upper surface and the lower surface are 2mm, the depth is 0.4 times of the diameter, namely the pores with the diameter of 0.8mm, and the inter-pore space is 2 mm. The preparation method comprises the following steps:

1. preparation of hierarchical porous materials

a. Material preparation

Cobalt-based alloy CoCrMo powder with the particle size of 100nm-150nm is used as a raw material, methylcellulose with the particle size of 500nm-750nm is used as a minimum-grade pore-forming agent, polystyrene with the particle size of 500nm-750nm is used as a binder, and the cobalt-based alloy powder is prepared by the following steps: methyl cellulose: polystyrene: distilled water is mixed according to the volume ratio of 2: 1: 1: 8, preparing slurry.

Adopting polyester foam with the edge diameter of 180-430 mu m, uniformly filling the slurry in the polyester foam by a foam impregnation method to form a blank body, drying, and crushing to obtain mixed particles containing the raw material, the pore-forming agent and the polyester foam, wherein the particles are 180-430 mu m.

b. And putting the mixed particles into a mold, and pressing into a compact green body.

c. Sintering the compact blank in vacuum; and carrying out subsequent treatment on the sintered blank according to the conventional process of the cobalt-based alloy CoCrMo to obtain the porous cobalt-based alloy material with the second grade.

2. Spinal implant processing

The shape and size of the spinal implant shown in the block diagram are machined.

Example 2

This example is similar to example 1 except that the material is pure titanium, the porosity of the pores is 55%, the upper and lower surfaces have pores with a diameter of 2.5mm and a depth of 1 time the diameter, i.e., 2.5mm, and the inter-pore spacing is 3 mm. The preparation method is similar to example 1.

Example 3

This example is similar to example 1 except that the material was niobium, the porosity of the pores was 53%, the walls of the through-holes on the upper and lower surfaces and between the upper and lower surfaces had holes with a diameter of 2.2mm and a depth of 0.6 times the diameter, i.e., 1.32mm, and the inter-hole spacing was 2.5 mm. The preparation method is similar to example 1.

Example 4

The embodiment is similar toembodiment 1, except that the material is carbonyl apatite, the porosity of the pores is 60%, the pore size of the macropores is 400-600 μm, the upper surface and the lower surface are provided with conical holes, the diameter of the small end of each conical hole is 2.5mm, the diameter of the large end of each conical hole is 3.2mm, the depth of each conical hole is 0.4 times of the diameter of the small end of each conical hole, namely 1mm, and the distance between the pores is 3.5 mm. The preparation method is similar to example 1.

Example 5

The embodiment is similar toembodiment 4, except that the material is stainless steel 316L, the porosity of the small holes is 68%, the pore size of the large holes is 300-550 μm, the upper surface, the lower surface and the wall of the through hole from the upper surface to the lower surface are provided with tapered holes, the diameter of the small end of each tapered hole is 2mm, the large end of each tapered hole is 3mm, the depth of each tapered hole is 1 time of the diameter of the small end, namely 2mm, and the distance between the holes is 3 mm. The preparation method is similar to example 1.

Example 6

A spinal implant is prepared from a porous tantalum material with a three-level pore structure, the pore size of a first-level pore cavity is 350-500 mu m, the pore size of a second-level pore cavity is 30-90 mu m, the pore size of a third-level pore cavity is 300-600 nm, and the porosity is 65%. The upper surface, the lower surface and the wall of the through hole between the upper surface and the lower surface are provided with taper holes, the diameter of the small end of each taper hole is 2.2mm, the diameter of the large end of each taper hole is 3.5mm, the depth of each taper hole is 0.8 time of the diameter of the small end of each taper hole, namely 1.76mm, and the distance between the holes is 3.8 mm. The preparation method is similar to that of example 1, except that in the preparation of the porous tantalum material, the crushed mixed particles and ethyl cellulose with the particle size of 40-100 mu m are mixed according to the volume ratio of 1: 3, uniformly mixing, pouring into three-dimensional through polyester foam with the edge diameter of 400-600 mu m and the aperture of 600-800 mu m, putting into a mold, pressing into a compact blank body, and sintering the compact blank body in vacuum; and carrying out conventional subsequent heat treatment on the sintered blank according to a tantalum material process to obtain a porous tantalum material with three-level pore grade, and then machining to obtain the shape and size of the spinal implant.

The inventor carries out implantation test on calf dorsal vertebra by using several spinal implants invented above and spinal implants made of the same material and having the largest-level hole, and immerses the implants in the bone growth factor solution before implantation to enable the implants to carry bone growth factors, and the result shows that after 12 weeks, bone tissues completely grow inside the implant of the invention, the spinal implant is tightly fused with surrounding bone tissues, the interface is stable, the depth of the bone tissue growth is still less than 3mm after 15 weeks of the spinal implant having only the single hole of the largest-level hole, and the whole spinal implant is not completely filled.

Claims (8)

1. A spinal implant made of a porous material, the spinal implant comprising a straight front end, an outwardly convex rear end, two ends extending between the front end and the rear end, an arcuate upper surface, a flat lower surface, the upper surface to the lower surface of the outer convex having a through hole, the rear end having a through hole extending inwardly from the rear end and communicating with the through hole from the upper surface to the lower surface, the spinal implant characterized in that: the porous material is a multi-level porous material, and the multi-level porous material is composed of all levels of cavities graded according to the pore sizes of the material and all levels of cavity walls surrounding the formed cavities; the cavity wall which surrounds a higher-level cavity in a three-dimensional space and is formed by a lower-level porous material, each level of cavity is communicated with each other, each level of cavity is also communicated with each other, the porosity of the minimum-level hole part material of the multi-level hole material is not less than 50%, and holes are formed in the upper surface and the lower surface; the hierarchical level of the hierarchical porous material is three levels, the aperture of the first-level pore cavity is a micron-level pore, the aperture of the third-level pore cavity is a nanometer-level pore, the aperture of the second-level pore cavity is between the apertures of the first-level pore cavity and the third-level pore cavity, and the aperture of the largest first-level pore of the hierarchical porous material is 100-600 mu m.

2. The spinal implant of claim 1, wherein: the wall of the through hole between the upper surface and the lower surface is provided with a hole.

3. The spinal implant of claim 1 or 2, wherein: the holes on the upper surface and the holes on the lower surface or the holes on the wall of the through hole between the upper surface and the lower surface are uniformly distributed.

4. The spinal implant of claim 1 or 2, wherein: the diameter of the hole is not less than 2mm, and the depth of the hole is 0.4-1 times of the diameter.

5. The spinal implant of claim 3, wherein: the diameter of the hole is not less than 2mm, and the depth of the hole is 0.4-1 times of the diameter.

6. The spinal implant of claim 1 or 2, wherein: the hole is a taper hole, the large end of the taper hole is arranged on the surface, the diameter of the small end of the taper hole is not less than 2mm, and the depth of the hole is 0.4-1 time of the diameter.

7. The spinal implant of claim 3, wherein: the hole is a taper hole, the large end of the taper hole is arranged on the surface, the diameter of the small end of the taper hole is not less than 2mm, and the depth of the hole is 0.4-1 time of the diameter.

8. A spinal implant as recited in any one of claims 1, 2, 5 or 7, wherein: the porous material is a porous metal material, a porous nonmetal material or a composite material of porous metal and nonmetal.

Images