Interbody fusion cage

Abstract

The utility model discloses an interbody fusion cage, relates to medical instrument technical field, mainly including: support frame and PEEK matrix, support frame includes first splint and second splint, first splint and second splint are arranged opposite to each other for clamping PEEK matrix, and support frame and PEEK matrix abut against each other, the supporting frame is made of a biocompatible material, and a first splint and a second splint of the supporting frame are both located on the outer side of the PEEK matrix and used for making contact with vertebrae. The supporting frame has good biocompatibility, bone grafting fusion can be promoted and the osseointegration effect can be improved after fusion, the supporting frame and the PEEK matrix with the low elastic modulus form the fusion cage, the overall elastic modulus of the fusion cage is moderate, the stress shielding effect can be reduced, and the fusion cage can be used for bone grafting fusion. Therefore, delayed healing and bone mass loss of adjacent segments are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, in particular to an intervertebral fusion device. Background Art

[0002] Lumbar degenerative diseases (including lumbar spinal stenosis, spondylolisthesis, degenerative scoliosis, and disc-derived diseases) and damage to lumbar structures are an important cause of low back and leg pain, sensory and motor impairment, and even loss of function. The principle of treatment is to relieve nerve compression and reconstruct spinal stability. Intervertebral fusion devices are implanted in the affected area to maintain intervertebral height and provide stable support for the lumbar segments after fusion surgery. Lumbar fusion has gradually developed into a standard method for treating lumbar degenerative diseases in clinical practice, but its postoperative complications have also attracted more and more attention and become a research hotspot.

[0003] In clinical spinal fusion surgery, if the elastic modulus of the fusion device is much higher than the elastic modulus of the vertebrae, it will cause a stress shielding effect (when two materials with different elastic moduli bear external forces together, the material with a high elastic modulus will bear more loads, while the material with a low elastic modulus will bear a lower load), thereby affecting postoperative bone healing and even causing loss of bone mass in adjacent segments. In addition, the high-strength mechanical support of the fusion device can also cause endplate damage, affecting the postoperative healing effect. On the other hand, if the elastic modulus of the fusion device is too low, it will lose its support effect due to its inability to bear the weight of the human body, resulting in surgical failure. Therefore, there is an urgent need to design a fusion device that has both a low elastic modulus and can provide sufficient mechanical strength.

[0004] Polyetheretherketone (PEEK) has good mechanical and physicochemical properties, and its elastic modulus is very close to that of human bone. It is widely used in medical implant materials. However, traditional PEEK fusion devices have poor biocompatibility and cannot promote bone growth at the bone graft fusion interface, affecting the postoperative treatment effect. In order to achieve better biocompatibility, there are currently two types of improved PEEK fusion devices. One is to use hydroxyapatite, which has good bone deposition properties, to apply a layer of PEEK and hydroxyapatite composite on the surface of the fusion device; the other is to use the good biocompatibility of titanium alloy and use titanium spraying technology on the surface of PEEK material to achieve the improvement of traditional PEEK fusion devices. However, both of these fusion devices have a coating, and shear force will occur during the implantation process, which may cause the surface coating material to peel off, greatly reducing the expected effect.

[0005] Patent CN107625564A discloses a lumbar intervertebral fusion device, which is a structural component formed by 3D printing using titanium alloy materials. Fusion devices made solely of titanium alloy materials have a stress shielding effect after being implanted in the lumbar spine because their elastic modulus is much higher than that of human bones. Therefore, it is necessary to design an intervertebral fusion device that has an elastic modulus that matches that of human bones, thereby minimizing the stress shielding effect and having good biocompatibility, promoting bone integration, and increasing its service life. Utility Model Content

[0006] The purpose of the utility model is to provide an intervertebral fusion device to solve the problems existing in the above-mentioned prior art, so that the elastic modulus is moderate, the stress shielding effect of the intervertebral fusion device can be reduced, and the device has good biocompatibility and promotes bone integration.

[0007] To achieve the above purpose, the utility model provides the following solutions:

[0008] The utility model provides an intervertebral fusion device, comprising: a support frame and a PEEK matrix, the support frame comprising a first splint and a second splint, the first splint and the second splint are arranged opposite to each other and are used to clamp the PEEK matrix, wherein the support frame is a frame made of a biocompatible material, and the first splint and the second splint of the support frame are both located on the outside of the PEEK matrix and are used to contact with vertebrae.

[0009] Preferably, the support frame is a titanium alloy frame.

[0010] Preferably, the support frame further includes a support column, wherein the support column is disposed between the first clamping plate and the second clamping plate, and the first clamping plate and the second clamping plate are fixedly connected via the support column.

[0011] Preferably, the support column includes two first support plates and two second support plates, the two first support plates are fixedly connected to the first clamping plate and are arranged on both sides of the first clamping plate, the two second support plates are fixedly connected to the second clamping plate and are arranged on both sides of the second clamping plate, and the first support plate is fixedly connected to the corresponding second support plate to form the support frame.

[0012] Preferably, the first support plate and the second support plate are both provided with corresponding holes, and the holes are for fixing pins to pass through, so that the corresponding support plates are fixedly connected.

[0013] Preferably, the first splint and the second splint have a flat surface on one side abutting against the PEEK matrix, and a curved surface away from the PEEK matrix, and the curved surface is used to contact the vertebrae.

[0014] Preferably, the PEEK matrix includes a first-end PEEK matrix and a second-end PEEK matrix, the first-end PEEK matrix and the second-end PEEK matrix are respectively arranged on both sides of the support column, and the planes of the first splint and the second splint can clamp the PEEK matrix, the end of the first-end PEEK matrix is ​​used to extend into the vertebral fusion space and close to the center of the vertebra, the end of the second-end PEEK matrix is ​​arranged in the vertebral fusion space and away from the center of the vertebra, and the first splint, the second splint, the first-end PEEK matrix and the second-end PEEK matrix can enclose a filling space for a bone graft.

[0015] Preferably, an end surface of the second end PEEK matrix away from the support column is provided with an opening for reducing the elastic modulus of the PEEK matrix.

[0016] Preferably, a bone grafting window is provided on the side of the PEEK matrix, and the bone graft is filled into the filling space through the bone grafting window.

[0017] Compared with the prior art, the utility model has achieved the following technical effects:

[0018] The first splint and the second splint of the support frame of the utility model are arranged opposite to each other and are used to clamp the PEEK matrix. The support frame is made of a biocompatible material, and its upper end and lower end are both connected to the vertebrae. It has good biocompatibility and can promote bone integration, which is beneficial to postoperative bone healing effect. The support frame and the PEEK matrix form a fusion device, so that the fusion device as a whole has a relatively moderate elastic modulus, which can reduce the stress shielding effect and avoid delayed healing and bone loss in adjacent segments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of the structure of the intervertebral fusion device in the embodiment of the utility model;

[0021] Figure 2 It is a schematic diagram of the support frame and the PEEK matrix being assembled into an intervertebral fusion cage in an embodiment of the utility model;

[0022] Figure 3 It is a stress statistical diagram of three fusion devices under static analysis in the embodiment of the utility model;

[0023] Figure 4 This is a stress variation diagram of three types of fusion devices in one vibration cycle under transient dynamic analysis in an embodiment of the utility model;

[0024] Figure 5 It is a stress distribution cloud diagram of the finite element analysis results of three types of fusion devices in the embodiment of the utility model.

[0025] In the figure: 1-PEEK matrix; 101-first end PEEK matrix; 102-second end PEEK matrix; 2-titanium alloy frame; 201-first splint; 202-second splint; 203-support column; 3-hole; 4-bone graft window; 5-opening. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] The purpose of the utility model is to provide an intervertebral fusion device to solve the problems existing in the prior art, so that the elastic modulus is moderate, the supporting effect is good, and the stress shielding effect after the intervertebral fusion device is implanted in the lumbar spine can be reduced. It also has good biocompatibility and can promote bone integration.

[0028] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] like Figure 1 and Figure 2As shown, the utility model provides an intervertebral fusion device, including: a support frame and a PEEK matrix 1, the support frame includes a first splint 201 and a second splint 202, the first splint 201 and the second splint 202 are arranged opposite to each other, the support frame is used to clamp the PEEK matrix 1, and the support frame abuts against the PEEK matrix 1, the support frame is a frame made of a biocompatible material, and the upper end and the lower end of the support frame and the first splint 201 and the second splint 202 are all connected to the vertebrae, the support frame has good biocompatibility and can promote bone integration, which is beneficial to the later treatment effect, and the PEEK matrix 1 is preferably a vertebral fusion device. The EK matrix 1 has a lower elastic modulus, and the support frame and the PEEK matrix 1 form a fusion device, so that the fusion device as a whole has a relatively moderate elastic modulus, thereby reducing the stress shielding effect of the intervertebral fusion device after implantation in the lumbar spine, avoiding delayed healing and adjacent segment bone loss; and the designed intervertebral fusion device is simulated by the finite element analysis method to simulate the mechanical effect after implantation in the human lumbar spine, and its design effect can be verified, which can not only effectively reduce stress shielding, but also reduce the upper maximum stress of the end plate and improve its stress distribution state, avoiding end plate collapse while ensuring mechanical support.

[0030] Moreover, the first splint 201 and the second splint 202 are interference-connected when combined with the PEEK matrix 1. After the intervertebral fusion device is implanted during fusion surgery, the first splint 201 and the second splint 202 must withstand a vertical physiological load, that is, the body's own weight, which is close to 500N. This makes the combined structure more solid and will not be dislocated or separated. In the finite element simulation, there has never been a case where the support frame and the PEEK matrix 1 are separated.

[0031] In the present embodiment, the support frame is a titanium alloy frame 2. Titanium alloy, as a highly biocompatible material, will not produce side effects or rejection reactions to human tissue. Titanium alloy has a microstructure and mechanical properties similar to bone tissue, and can promote bone cell growth and regeneration. At the same time, titanium alloy has excellent mechanical properties, high strength and light weight, and will not break or fatigue under long-term load. The titanium alloy frame with a large elastic modulus is matched with a PEEK matrix with a small elastic modulus to provide a suitable elastic modulus. In addition, titanium alloy is also corrosion-resistant and can be used for a long time in the human body without degradation. It should be noted that support frames of other materials can also be used, but they need to have good biocompatibility and suitable elastic modulus, for example, a support frame made of tantalum metal or a support frame made of magnesium alloy.

[0032] In this embodiment, the titanium alloy frame 2 also includes a support column 203, which is arranged between the first clamping plate 201 and the second clamping plate 202. The first clamping plate 201 and the second clamping plate 202 are fixedly connected through the support column 203. The support column 203 includes two first support plates and two second support plates. The two first support plates are fixedly connected to the first clamping plate 201 and are arranged on both sides of the first clamping plate 201. The two second support plates are fixedly connected to the second clamping plate 202 and are arranged on both sides of the second clamping plate 202. The first support plate is fixedly connected to the corresponding second support plate. The split design of the titanium alloy frame 2 facilitates the clamping and locking of the PEEK matrix 1, making the connection between the two more secure. It should be noted that, under the premise of ensuring the reliability of the abutment between the PEEK matrix 1 and the titanium alloy frame 2, the first clamping plate, the second clamping plate and the support column can be integrally formed.

[0033] In this embodiment, holes 3 are provided on both the first support plate and the second support plate, and the holes 3 are for fixing pins to pass through so that the two support columns 203 are fixedly connected. Multiple holes 3 are provided along the height direction of the support columns 203, so that the support columns 203 of the first clamping plate 201 and the support columns 203 of the second clamping plate 202 can be fixed at multiple points, and the connection is more secure. It should be noted that threaded holes can also be provided on the support columns, and then screws can be used to lock and fix the two support columns, or other fixing methods can be used to fix the two support columns. It should also be noted that the clamping space of the first clamping plate 201 and the second clamping plate 202 can be adjusted by aligning different numbers of holes 3 to adapt to PEEK matrices of different heights.

[0034] In the present embodiment, the first splint 201 and the second splint 202 both include a curved surface and a flat surface, and the cross-section of the first splint 201 and the second splint 202 is a trapezoidal surface, the curved surface is the upper bottom of the trapezoidal surface, and the flat surface is the bottom surface of the trapezoidal surface. The flat surface is used to contact the PEEK matrix 1, and the curved surface is used to contact the bone adjacent to the titanium alloy frame 2. The surface in contact with the bone is a curved surface, which fits well with the bone surface, is convenient for implantation, can avoid the generation of stress concentration as much as possible, and is convenient for the activity and growth of the bone. The surface that conflicts with the PEEK matrix 1 adopts a flat surface, and the cross-sectional area of ​​the flat surface is greater than the cross-sectional area of ​​the curved surface, so that the PEEK matrix 1 can be bound in a larger area, ensuring that the titanium alloy frame 2 and the PEEK matrix 1 are reliably abutted.

[0035] In this embodiment, the PEEK matrix 1 includes a first-end PEEK matrix 101 and a second-end PEEK matrix 102, the first-end PEEK matrix 101 and the second-end PEEK matrix 102 are respectively arranged on both sides of the support column 203, and the planes of the first splint 201 and the second splint 202 can clamp the PEEK matrix 1, and the first splint 201, the second splint 202, the first-end PEEK matrix 101 and the second-end PEEK matrix 102 enclose a filling space for a bone graft, which is used to fill the bone graft. The end of the first-end PEEK matrix 101 is used to extend into the vertebral fusion space and is close to the center of the vertebra, and the end of the second-end PEEK matrix 102 is arranged in the vertebral fusion space and away from the center of the vertebra. The vertebral fusion space mentioned here is the space where the intervertebral fusion device needs to be implanted. The first-end PEEK matrix 101 extends into the fusion space closer to the center of the vertebra, and the second-end PEEK matrix 102 is closer to the edge of the bone. Both ends of the first end PEEK matrix 101 and the second end PEEK matrix 102 are respectively against the planes of the first clamping plate 201 and the second clamping plate 202 , and the split PEEK matrix is ​​convenient for being inserted into the titanium alloy support frame.

[0036] In this embodiment, the end surface of the second end PEEK matrix 102 away from the support column 203 is provided with an opening 5, the shape and position of the opening 5 are the result of topological optimization, and the opening 5 can not only reduce the overall elastic modulus of the intervertebral fusion device, but also remove excess material, save costs, and facilitate bone graft filling after the fusion device is implanted. It should be noted that, under the premise of ensuring a suitable elastic modulus, the opening can also be not provided, or multiple openings can be provided.

[0037] In this embodiment, a bone grafting window 4 is provided on the side of the PEEK matrix, and the bone graft is filled into the bone graft filling space through the bone grafting window 4. Preferably, four bone grafting windows 4 are provided, one each on both sides of the first end PEEK matrix 101 and the second end PEEK matrix 102, so as to facilitate the multi-directional filling of the bone graft through the bone grafting window 4, so that the filling of the bone graft is more sufficient and faster.

[0038] like Figure 3 As shown, Figure 3 The stress magnitudes of three different fusion cages under six working conditions, namely, flexion, extension, left and right lateral bending, and left and right rotation, were statistically analyzed. It can be seen that the intervertebral fusion cage in this embodiment can reduce the stress of the fusion cage and reduce the risk of endplate damage.

[0039] like Figure 4 As shown, Figure 4 The stress changes of three different fusion cages in one vibration cycle under transient dynamic analysis are shown. It can be found that the stress of the intervertebral fusion cage in this example is significantly lower than that of the titanium alloy fusion cage in the entire vibration cycle.

[0040] like Figure 5 As shown, Figure 5 The stress distribution cloud diagram in the finite element analysis results of the fusion device is given. By comparison and analysis, it can be seen that the stress distribution on the titanium alloy frame in the intervertebral fusion device in this embodiment is greater, it effectively bears the applied load, plays a good mechanical support effect, and the overall stress distribution is more uniform, while the stress of the titanium alloy fusion device is concentrated on the surface or one side. The PEEK fusion device shows the same rule, and the effect is not as good as the intervertebral fusion device in this embodiment.

[0041] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An intervertebral fusion cage, characterized in that: The invention comprises a support frame and a PEEK matrix, wherein the support frame comprises a first splint and a second splint, wherein the first splint and the second splint are arranged opposite to each other and used to clamp the PEEK matrix, wherein the support frame is a frame made of a biocompatible material, and the first splint and the second splint of the support frame are both located on the outside of the PEEK matrix and used to contact the vertebrae.

2. The intervertebral fusion cage according to claim 1, characterized in that: The supporting frame is a titanium alloy frame.

3. The intervertebral fusion cage according to claim 1 or 2, characterized in that: The support frame further includes a support column, wherein the support column is disposed between the first clamping plate and the second clamping plate, and the first clamping plate and the second clamping plate are fixedly connected via the support column.

4. The intervertebral fusion cage according to claim 3, characterized in that: The support column includes two first support plates and two second support plates, the two first support plates are fixedly connected to the first clamping plate and are arranged on both sides of the first clamping plate, the two second support plates are fixedly connected to the second clamping plate and are arranged on both sides of the second clamping plate, and the first support plate is fixedly connected to the corresponding second support plate to form the support frame.

5. The intervertebral fusion cage according to claim 4, characterized in that: The first support plate and the second support plate are both provided with corresponding holes, and the holes are for fixing pins to pass through, so that the corresponding support plates are fixedly connected.

6. The intervertebral fusion cage according to claim 3, characterized in that: The first splint and the second splint have a flat surface on one side abutting against the PEEK matrix and a curved surface away from the PEEK matrix, and the curved surface is used to contact the vertebrae.

7. The intervertebral fusion cage according to claim 6, characterized in that: The PEEK matrix includes a first-end PEEK matrix and a second-end PEEK matrix, the first-end PEEK matrix and the second-end PEEK matrix are respectively arranged on both sides of the support column, and the planes of the first splint and the second splint can clamp the PEEK matrix, the end of the first-end PEEK matrix is ​​used to extend into the vertebral fusion space and close to the center of the vertebra, the end of the second-end PEEK matrix is ​​arranged in the vertebral fusion space and away from the center of the vertebra, and the first splint, the second splint, the first-end PEEK matrix and the second-end PEEK matrix can enclose a filling space for a bone graft.

8. The intervertebral fusion cage according to claim 7, characterized in that: An end surface of the second end PEEK matrix away from the support column is provided with an opening for reducing the elastic modulus of the PEEK matrix.

9. The intervertebral fusion cage according to claim 7, characterized in that: A bone grafting window is provided on the side of the PEEK matrix, and the bone graft is filled into the filling space through the bone grafting window.

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