CN105615972B - A kind of cervical intervertebral emerging system - Google Patents

Abstract

The invention discloses a kind of cervical intervertebral emerging systems, including fusion main body, and upper limb curved-surface structure and lower edge curved-surface structure is respectively set in the both ends of the fusion main body；The fusion main body has the hollow columnar structures through upper lower edge curved-surface structure, and fusion body surfaces distribution is provided with the viewing hole of multiple connection hollow columnar structures；The surface of upper limb curved-surface structure and lower edge curved-surface structure is distributed with tapered protrusion.The cervical intervertebral emerging system and terminal plate of vertebral body fitness are good, and contact surface is the combination of ideal surface-to-surface, and biomethanics is stablized.

Description

A cervical intervertebral fusion system

technical field

The invention belongs to the technical field of cervical spine medical devices and relates to a cervical spine intervertebral fusion system.

Background technique

Anterior cervical surgery often requires subtotal resection of 1-2 vertebral bodies to complete the decompression. For the gap left after the resection, the roughly measured titanium mesh is usually used to fill the gap in clinical practice. Due to the poor fit between the planar structure of the titanium mesh and the curved surface structure of the human cervical vertebral endplate, postoperative titanium mesh subsidence and displacement lead to internal fixation failure, and even spinal cord injuries often occur in severe cases. Therefore, there is an urgent clinical need for a cervical intervertebral filler with high fit and good biomechanical stability to replace the titanium mesh.

The complex structure of the spine, with its anatomical and mechanical complexity, is a challenging subject, both from a diagnostic and surgical point of view. Vertebral morphology, biomechanics, and motor units vary widely across all anatomical segments, especially in the cervical spine. The above-mentioned situation makes spinal internal fixation materials and fixation methods constantly innovated. In the early 1980s, Patel et al. introduced titanium alloy into orthopedic surgery in the shape of a metal mesh plate, and used it for maxillofacial bone reconstruction and acetabular replacement surgery. Since then, titanium mesh structures have been commonly used to treat bone defects by properly cutting and shaping them to fill bone defects and provide support to the target area. In 1986, Harms and Biedermann invented the first "titanium mesh" implant for the spine, which was designed as an elliptical grid column and used as a spinal gasket to provide support for bone tissue. Due to the high fusion of the spine provided by titanium mesh technology Currently, it has become the most commonly used implant after subtotal cervical corpectomy. Anterior cervical subtotal corpectomy combined with titanium mesh bone grafting and titanium plate internal fixation is suitable for the treatment of cervical diseases including cervical spondylosis, cervical disc herniation, cervical trauma, cervical tuberculosis, etc., and has achieved good results, effectively avoiding the Complications such as infection, fracture, and long-term pain in the donor site may be caused by autologous ilium bone grafting. Titanium mesh is used in cervical spine surgery, which can provide sufficient support and provide a suitable fusion environment for bone grafts. However, due to the complexity of the spine itself and its surrounding structures, the use of titanium mesh still has many disadvantages. Due to the differences in biomechanical indicators such as the rigidity of the titanium mesh and the human cervical spine, the titanium mesh sinks and penetrates into the adjacent vertebral body after surgery. The plate and finally lead to the loosening or breaking of the titanium plate screws, and the displacement of the titanium mesh. The clinical diagnosis of titanium mesh subsidence is based on the height of the anterior edge or posterior edge of the intervertebral segment on the standard lateral X-ray film of the cervical spine at 3 months, 6 months, and 12 months after operation, which is consistent with the results of the film within 1 week after operation. If one of the three intervertebral height subsidence is greater than or equal to 2mm, it is considered as titanium mesh subsidence. The reason for the sinking of the titanium mesh is considered to be due to multiple factors. Among them, the matching degree of the contact surface between the titanium mesh and the endplate is a key factor. According to research by LimTH and Hakalo et al., postoperative subsidence of the titanium mesh may have a small contact area with the titanium mesh and the adjacent endplate, and the inclination angle of the endplate has not been considered, resulting in poor matching between the titanium mesh and the adjacent endplate, and poor fit. , prone to subsidence in the early postoperative period. They believed that improving the fit between the titanium mesh and the adjacent endplate is of great significance to reduce the subsidence of the titanium mesh. Daubs et al. reviewed 27 cases of anterior cervical subtotal corpectomy, titanium mesh autograft and anterior plate surgery. During the 21-month follow-up period, the overall failure rate was 30%, and the single-segment failure rate was 6%. , significantly lower than the multi-segment average failure rate of 75% (two-segment 67%, three-segment 100%). He believes that in addition to the poor physical condition of the patient, the sharp edge and high hardness of the titanium mesh, and the decompression technique, factors such as biomechanical changes caused by reconstruction after multi-segmental subtotal corpectomy are also critical. Jonbergen et al. reviewed 71 cases of cervical intervertebral disc disease and cervical spinal stenosis, and found that 10 cases had subsidence, mainly concentrated in the C6/7 segment, and believed that the reason may be related to the design defect of titanium mesh. Similar to foreign scholars, Chinese scholars have also done a lot of research on the complications related to titanium mesh. According to research by Li Xinyou et al., the local stress concentration of the sharp titanium mesh is easy to puncture the adjacent endplate and enter the cancellous bone of the vertebral body, and related complications such as subsidence and displacement of the titanium mesh are prone to occur after surgery. Research by Xu Jianwei and Jia Lianshun et al. found that titanium mesh bone graft has advantages over autogenous ilium bone graft, but there is a possibility of subsidence, which is related to the small contact area of titanium mesh and poor intervertebral stress distribution after cutting. However, a large number of clinical data show that the fit between the titanium mesh and the vertebral body endplate is not good, resulting in the contact surface changing from an ideal surface-surface combination to a point-surface combination, relatively concentrated stress, and changes in biomechanical stability. The main reason for the bit.

It can be seen that there is an urgent need to develop a cervical intervertebral fusion system with stable structure and good mechanical properties.

Contents of the invention

In order to solve the problems existing in the prior art, the present invention provides a novel individualized cervical intervertebral fusion system to replace the titanium mesh. The cervical intervertebral fusion system has a good fit with the endplate of the vertebral body, the contact surface is an ideal surface-surface combination, and the biomechanics is stable.

The present invention is achieved through the following technical solutions:

A cervical intervertebral fusion system, comprising a fusion main body, the two ends of the fusion main body are respectively provided with an upper edge curved surface structure and a lower edge curved surface structure integrally formed with it; the fusion main body has a hollow column that runs through the upper and lower edge curved surface structures Structure, the surface of the fusion main body is distributed with a plurality of visible holes connecting the hollow columnar structure; the surfaces of the upper edge curved surface structure and the lower edge curved surface structure are distributed with conical protrusions; the upper edge curved surface structure and the fusion upper position The structure of the lower endplate of the cervical spine matches to form surface-to-surface contact; the curved surface structure of the lower edge matches the structure of the upper endplate of the fused lower cervical spine to form surface-to-surface contact.

As a further improvement of the present invention, the cross-sectional area of the curved surface structure of the upper edge and the curved surface structure of the lower edge is larger than the cross-sectional area of the fusion main body, and smaller than the cross-sectional area of the endplate of the cervical spine.

As a further improvement of the present invention, the shape of the visible hole is triangular, and adjacent triangles are arranged alternately on the fusion main body to form a network structure.

As a further improvement of the present invention, it also includes fixation screws for fixing with the cervical vertebrae, at least two fixation screws obliquely pass through the upper edge curved surface structure and the lower edge curved surface structure respectively to connect with the cervical vertebrae.

As a further improvement of the present invention, the upper curved surface structure and the lower curved surface structure are also provided with bolt stoppers for preventing the fixing screws from falling off, and the bolt stoppers are arranged laterally and contact with the nuts of the fixing screws.

As a further improvement of the present invention, all parts of the cervical intervertebral fusion system are made of titanium.

As a further improvement of the present invention, the cervical intervertebral fusion system is integrally formed by 3D printing titanium alloy metal powder through an electron beam melting process.

Compared with the prior art, the present invention has the following beneficial effects:

The cervical intervertebral fusion system of the present invention includes a fusion main body, an upper edge curved surface structure and a lower edge curved surface structure; a hollow columnar structure is used for filling aggregate and fusion of the aggregate and cervical vertebrae; the surfaces of the upper edge curved surface structure and the lower edge curved surface structure Conical protrusions are evenly distributed to prevent the fusion system from slipping. The curved surface structure of the upper edge and the curved surface structure of the lower edge of the structure have a good fit with the endplate of the vertebral body to be fused, the contact surface is an ideal surface-surface combination, and the biomechanics is stable. It can replace ordinary titanium mesh to ensure the structural stability of the fusion body and prevent stress concentration.

Further, the titanium alloy metal powder is 3D printed to make an individualized cervical intervertebral fusion system. The curved surface structure of the upper and lower edges of the intervertebral fusion system can perfectly fit with the upper and lower endplates of the cervical spine, truly achieving the ideal surface-to-surface integration.

Furthermore, the shape of the visible hole is an equilateral triangle, and the staggered configuration of the triangular structure increases the stability of the fusion body and prevents the fusion body from being deformed by force.

Description of drawings

Fig. 1 is a schematic diagram 1 of the cervical intervertebral fusion system in Embodiment 1;

2 is a second schematic diagram of the cervical intervertebral fusion system in Embodiment 1;

Fig. 3 is the schematic diagram of embodiment 2 cervical intervertebral fusion system with fixation screws;

Fig. 4 is a schematic diagram of the application of the cervical intervertebral fusion system with fixation screws.

Among them, 1. Upper edge curved surface structure; 2. Fused main body; 3. Lower edge curved surface structure; 4. Hollow columnar structure; 5. Tapered protrusion; 6. Visible hole; 7. Fixing screw; 9. Upper vertebral body; 10. Removal of vertebral body; 11. Lower vertebral body; 12. Bolt retainer.

Detailed ways

Below, with reference to the accompanying drawings and examples, specific embodiments of the present invention are given, and the present invention is further described.

Example 1

As shown in Figure 1, a cervical intervertebral fusion system of the present invention includes a fusion main body 2, and the two ends of the fusion main body 2 are respectively provided with an upper edge curved surface structure 1 and a lower edge curved surface structure 3; the fusion main body 2 The hollow columnar structure 4 with the curved surface structure running through the upper and lower edges is used for filling aggregates, and a plurality of visible holes 6 communicating with the hollow columnar structure 4 are arranged on the surface of the fusion body 2 . The visible hole 6 can facilitate the observation of the internal aggregate when the aggregate is fully filled; the surface of the upper edge curved surface structure 1 and the lower edge curved surface structure 3 are both distributed with conical protrusions 5 . All parts of the cervical intervertebral fusion system are made of titanium alloy metal powder through 3D printing or other common processes. The main body 2, the upper edge curved surface structure 1 and the lower edge curved surface structure 3 are integrated into one structure.

As shown in Figure 2, 3D printing technology is used to match the upper edge curved structure 1 with the lower endplate structure of the upper fused cervical vertebrae; the lower edge curved surface structure 3 matches the upper endplate structure of the lower fused cervical vertebrae. And the front end of the upper edge curved surface structure 1 is an upward convex surface, and the front side of the lower edge curved surface structure 3 is a downward convex surface. It can make the contact surface of the fusion system and the cervical vertebra body an ideal surface-to-surface combination, with good contact and increased stability. The cross-sectional area of the upper edge curved surface structure 1 and the lower edge curved surface structure 3 is larger than that of the fusion main body 2 . The force of the fusion main body 2 can be effectively dispersed, and the problems of stress deformation of a single titanium mesh and the like are solved. Smaller than the cross-sectional area of the cervical vertebral endplate, it effectively avoids compression of the fused cervical vertebrae. The front and rear surfaces of the upper and lower edge curved structures are both plane structures, and the corresponding plane structures of the upper edge curved structure 1 and the lower edge curved structure 3 are flush up and down, which is convenient for the fusion system to be fixed with the anterior cervical titanium plate.

Preferably, the shape of the visible hole 6 is a regular triangle, and adjacent regular triangles are arranged on the fusion main body 2 alternately. The staggered arrangement of triangular structures increases the stability of the fusion body 2 and prevents the fusion body 2 from being deformed by force. And the equilateral triangles are arranged on the shape, and the appearance is beautiful.

Example 2

As shown in FIG. 3 , the cervical intervertebral fusion system also includes fixation screws 7 for fixing to the cervical vertebrae. At least two fixation screws 7 obliquely pass through the upper edge curved surface structure 1 or the lower edge curved surface structure 3 to connect with the cervical vertebrae. The upper edge curved surface structure 1 and the lower edge curved surface structure 3 are also provided with bolt stoppers 12 for preventing the fixing screws 7 from falling off.

As shown in Figure 4, the cervical vertebral body that continuous upper vertebral body 9, excision vertebral body 10, lower vertebral body 11 are formed, after subtotal resection of vertebral body 10 after operation, the cervical vertebra intervertebral fusion system of the present invention is installed and fixed on the upper position Between the vertebral body 9 and the lower vertebral body 11, it is fastened by an upwardly inclined fixing screw and an obliquely downward fixing screw. After fastening, the bolt stopper 12 is arranged laterally to prevent the fixing screw from falling off later. The bolt retaining body 12 is a rod-shaped structure.

Verification test: Select 9 fresh adult cervical spine cadaver specimens soaked in formalin (the specimens are provided by the Human Anatomy Research Office of Xi'an Jiaotong University School of Medicine), conduct CT scans on 9 specimens, and design subtotal resection through CT C3, C4, C5, C6, C7, C3/4, C4/5, C5/6, C6/7 behind the vertebral body and the individualized cervical intervertebral fusion system that fully fits the upper and lower endplates of the adjacent vertebral body, Titanium alloy powder was 3D printed into the designed intervertebral fusion system using EBM technology, and 1 to 2 vertebral bodies of 9 specimens were subtotally resected according to the plan, and the corresponding individualized cervical intervertebral fusion system was installed, and the length was used. Appropriate anterior cervical titanium plate fixation, and finally evaluate the biomechanical stability of the specimen in four states of axial compression, flexion, extension, and lateral flexion.

The produced cervical intervertebral fusion system needs to fit perfectly with the upper and lower endplates of the adjacent vertebral bodies after implantation. After being fixed with an anterior cervical titanium plate, the individualized cervical intervertebral fusion system should be axially compressed and anterior to the cervical spine. The biomechanics are stable under the four states of flexion, extension, and lateral flexion, and there are no complications such as subsidence and displacement of implants.

Claims (2)

1. A cervical intervertebral fusion system, characterized in that: comprising a fusion main body (2), the two ends of the fusion main body (2) are respectively provided with an upper edge curved surface structure (1) and a lower edge curved surface structure integrally formed with it (3), the outer walls of both ends of the fusion body (2) are provided with annular reinforcement structures; the fusion body (2) has a hollow columnar structure (4) that runs through the curved surface structure of the upper and lower edges, and the surface of the fusion body (2) is distributed with A plurality of visible holes (6) communicating with the hollow columnar structure (4); tapered protrusions (5) are distributed on the surface of the upper edge curved surface structure (1) and the lower edge curved surface structure (3); The curved surface structure of the upper edge (1) matches the structure of the lower endplate of the fused upper cervical vertebra to form surface-to-surface contact and completely fit; the curved surface structure of the lower edge (3) matches the structure of the upper endplate of the fused lower cervical vertebra to form surface-to-surface contact and completely fit; The cross-sectional area of the upper edge curved surface structure (1) and the lower edge curved surface structure (3) is larger than the cross-sectional area of the fusion main body (2), and smaller than the cross-sectional area of the cervical vertebral endplate; The visible holes (6) are triangular in shape, and adjacent triangles are interlaced on the fusion main body (2) to form a network structure; It also includes fixation screws (7) for fixing to the cervical vertebrae, at least two fixation screws (7) obliquely pass through the upper edge curved surface structure (1) and the lower edge curved surface structure (3) to connect with the cervical vertebrae; The upper edge curved surface structure (1) and the lower edge curved surface structure (3) are also provided with a bolt retainer (12) for preventing the fixing screw (7) from falling off, and the bolt retainer (12) is arranged laterally and connected with the fixation screw (7) the nut contacts; The cervical intervertebral fusion system is formed by 3D printing of titanium alloy metal powder through the electron beam melting process. 2. The cervical intervertebral fusion system according to claim 1, characterized in that: all parts of the cervical intervertebral fusion system are made of titanium.