Atlantoaxial joint fusion cage

Abstract

The utility model provides an atlantoaxial joint fusion cage which comprises a fusion cage body with round and blunt peripheral corners, the fusion cage body is an ellipse-like hollow polyhedron, the hollow polyhedron is divided into a front supporting section and a rear supporting section, and the front supporting section is a cone composed of four faces or is in a streamline shape so as to facilitate implantation of the fusion cage; the rear supporting section is in a cuboid shape, the rear end face of the rear supporting section is sequentially provided with an opening groove, a rectangular opening and a screw hole from one side to the other side, an inserting piece is arranged in the fusion cage body, the inserting piece penetrates through the rectangular opening and then inclines upwards, and barb structures are arranged on the two sides of the inserting piece. The anatomical structure conforming to the atlantoaxial joint gap in appearance is adopted, after the anatomical structure is implanted into the atlantoaxial joint gaps on the two sides, surrounding loose joint capsules generate tension so that the atlantoaxial joints can be immediately stabilized, bone grafting fusion can be faster and better in the internal fixation stable period, and then the purpose of atlantoaxial stabilization is achieved; the atlantoaxial dislocation or instability can be effectively treated.

Description

Technical Field

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

[0002] The occipital-cervical region is the most flexible area of ​​the spine, and the atlantoaxial anatomical structure is special, which carries important joint activities and mechanical stability transmission of the occipital-cervical region. However, congenital malformations, trauma, tumors, tuberculosis, rheumatoid arthritis, ankylosing spondylitis and other lesions of the occipital-cervical region can cause dislocation or instability of the atlantoaxial joint. Acute atlantoaxial dislocation can cause severe spinal cord injury in patients, resulting in quadriplegia, or even involvement of the medulla oblongata and death; chronic atlantoaxial dislocation can cause continuous compression of the ventral side of the spinal cord and gradually lead to symptoms of weakness or even paralysis of the patient's limbs. The occipital-cervical region has important spinal cords and blood vessels, with complex structures and diverse anatomical variations. Therefore, reconstructing the stability of the atlantoaxial complex is extremely challenging for spinal surgeons.

[0003] Traditional posterior atlantoaxial fusion is the main method to solve atlantoaxial instability or dislocation. It uses internal fixation to fix the loose atlas and axis together, and bone is grafted between the posterior arch of the atlantoaxial and the spinous process of the axis to promote atlantoaxial fusion and ultimately achieve stability of the atlantoaxial complex. However, many basic studies and clinical practices have shown that the various single internal fixation implants currently available have shortcomings and defects, and the final clinical bone graft fusion rate, biomechanical stability, and clinical effects have different advantages and disadvantages. The main surgical methods are: (1) Occipitocervical fusion: As a traditional posterior surgical method, although it is widely applicable, it limits the movement of the skull and neck; in addition, if the odontoid process continues to compress the ventral side of the spinal cord and the symptoms are not relieved, transoral odontoid resection is still required. Therefore, it is currently only used as a remedial measure when other surgical methods fail. (2) Atlantoaxial titanium cable fixation (Gallie and Brooks technique), Halifax lamina clamp, and Apofix lamina hook techniques: There is a possibility that the titanium cable may cut the lamina and damage the spinal cord. The biomechanical stability provided by this technique is limited. The atlantoaxial joint cannot be reduced during surgery, and the ventral compression of the spinal cord cannot be relieved. In addition, patients cannot obtain immediate or long-term stability after surgery, and the bone graft fusion rate is low. It is rarely used now. (3) Atlantoaxial screw fixation: It can most effectively control the stability of atlantoaxial rotation, flexion and extension, and lateral flexion. However, this technique requires the atlantoaxial joint to reach an anatomical reduction state before surgery, and requires a large screw insertion angle, which may cause screw implantation failure and damage to the vertebral artery. (4) Atlantoaxial pedicle screw technique: It can obtain strong atlantoaxial stability and can perform atlantoaxial lifting and reduction during surgery, but it cannot be used in patients with vertebral artery and bone anatomical abnormalities such as high vertebral artery overriding. (5) Axis lamina screw technique: It can be used as a remedial method for patients with high vertebral artery straddling, but the screw has the risk of penetrating the lamina from the side and distal end, causing spinal cord injury. Especially for patients with osteoporosis, the risk of screw pullout is higher. The above-mentioned various internal fixation methods all use bone grafting fusion between the posterior arch of the atlas and the spinous process of the axis lamina. Not only does it require a large amount of bone grafting, but the bone grafting area is located in the posterior tension zone, lacks bone stress conduction, and is biomechanically unreasonable, which may ultimately affect the bone graft fusion rate. Regardless of the type of internal fixator used, its purpose is to create conditions for bone graft fusion, so that the bone graft can fuse as quickly as possible during the limited mechanical stability period of internal fixation, and finally achieve a firm bone fusion of the atlantoaxial vertebra. Previous studies have shown that the longitudinal stress load between the atlantoaxial vertebrae is mainly transmitted to the lower cervical spine through the atlantoaxial joint, and a certain stress stimulation will promote the fusion of the bone graft. Therefore, bone grafting fusion in the atlantoaxial joint space is more in line with the requirements of anatomy and biomechanics.

[0004] Intervertebral fusion cages have been widely used in surgeries of the cervical, thoracic and lumbar spine, and have achieved impressive clinical results. However, they have the following technical defects: existing intervertebral fusion cages are designed for use in the lower cervical and lumbar spine, and their appearance and use are very different from the anatomical characteristics of the atlantoaxial joint structure.

[0005] Therefore, how to design an atlantoaxial joint fusion device has become an urgent problem to be solved. Utility Model Content

[0006] In view of the problems existing in the prior art, the utility model provides an atlantoaxial joint fusion device to solve at least one of the above technical problems.

[0007] The technical solution of the utility model is: an atlantoaxial joint fusion device, comprising a fusion device body with a rounded circumference, the fusion device body is an elliptical hollow polyhedron, the hollow polyhedron is divided into a front support section and a rear support section, the front support section is a cone composed of four faces or is streamlined to facilitate the implantation of the fusion device; the rear support section is in the shape of a rectangular parallelepiped, and an opening groove, a rectangular opening, and a screw hole are sequentially arranged on the rear end surface of the rear support section from one side to the other side, an insert is arranged in the fusion device body, the insert passes through the rectangular opening and tilts upward, and barb structures are arranged on both sides of the insert.

[0008] The utility model adopts a fusion device body with a rounded angle to prevent damage to peripheral nerves and tissues during implantation of the fusion device; the screw hole matches the corresponding instrument to facilitate the holding and implantation of the fusion device; the rectangular opening is convenient for the entry of subsequent inserts, and the barb structure design is adopted to prevent the inserts from falling out; the shape conforms to the anatomical structure of the atlantoaxial joint space, and after being implanted in the atlantoaxial joint space on both sides, the surrounding loose joint capsule generates tension to achieve immediate stability of the atlantoaxial joint, and makes the bone graft fusion faster and better during the internal fixation stabilization period, thereby achieving the purpose of atlantoaxial stabilization; it has the functions of braking, increasing the height of the joint surface and bone fusion, and can effectively treat atlantoaxial dislocation or instability; the structure is reasonable and easy to use, and it complements the existing posterior atlantoaxial internal fixation system, and provides a practical and effective internal fixation fusion technology for bone graft fusion of atlantoaxial dislocation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is the front view of the installation structure of the utility model.

[0010] Figure 2 This is a three-dimensional diagram of the fusion device body of the utility model.

[0011] Figure 3 It is a cross-sectional view of the fusion device body of the present utility model.

[0012] Figure 4 It is a three-dimensional diagram of the insert of the utility model.

[0013] Figure 5 It is a schematic diagram of the use structure of the utility model.

[0014] In the figure: 1. fusion device body; 2. insert; 101. opening slot; 102. rectangular opening; 103. screw hole; 201. insert block; 202. barb structure; 203. through hole. DETAILED DESCRIPTION

[0015] The utility model is further described below in conjunction with the accompanying drawings.

[0016] See also Figure 1-5 The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the utility model, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the utility model without affecting the effects and purposes that can be achieved by the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the utility model. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the utility model without substantial change of the technical content.

[0017] Embodiment 1: An atlantoaxial joint fusion device, referring to Figure 1 , Figure 2 , Figure 5The invention comprises a fusion device body 1 with rounded corners, wherein the fusion device body 1 is an elliptical hollow polyhedron, which is divided into a front support section and a rear support section. The front support section is a cone or streamlined shape composed of four faces, with rounded corners and a smooth surface. It is the front end of the fusion device when implanted, so as to facilitate the implantation of the fusion device; the rear support section is in the shape of a rectangular parallelepiped, and the end face and left and right side faces of the rear end are rectangular, and the upper and lower faces in contact with the atlantoaxial joint surface are square, and the upper and lower faces of the square are hollowed out in the middle to accommodate more bone grafts. The block is conducive to fusion, and its two side surfaces are provided with inverted teeth or triangular protrusions throughout to prevent the withdrawal of the fusion device; the rear end surface of the rear support segment is provided with an opening groove 101, a rectangular opening 102, and a screw hole 103 from one side to the other side, and an insert 2 is provided in the fusion device body 1. The insert 2 passes through the rectangular opening 102 and then tilts upward. Barb structures 202 are provided on both sides of the insert 2; the upper edge of the fusion device body 1 is arc-shaped, which fits the curvature of the lower edge of the atlas; the lower edge is straight; and the upper and lower edges are designed with anti-slip teeth. The utility model adopts a fusion device body with a rounded angle to prevent damage to peripheral nerves and tissues during implantation of the fusion device; the screw hole matches the corresponding instrument to facilitate the holding and implantation of the fusion device; the rectangular opening is convenient for the entry of subsequent inserts, and the barb structure design is adopted to prevent the inserts from falling out; the shape conforms to the anatomical structure of the atlantoaxial joint space, and after being implanted in the atlantoaxial joint space on both sides, the surrounding loose joint capsule generates tension to achieve immediate stability of the atlantoaxial joint, and makes the bone graft fusion faster and better during the internal fixation stabilization period, thereby achieving the purpose of atlantoaxial stabilization; it has the functions of braking, increasing the height of the joint surface and bone fusion, and can effectively treat atlantoaxial dislocation or instability; the structure is reasonable and easy to use, and it complements the existing posterior atlantoaxial internal fixation system, and provides a practical and effective internal fixation fusion technology for bone graft fusion of atlantoaxial dislocation.

[0018] Embodiment 2: Based on Embodiment 1, refer to Figure 3 The opening slot 101 is an L-shaped structure, and the L-shaped structure can be arranged corresponding to the holding end of the holder. The utility model adopts an L-shaped opening slot, which is convenient for the holder to hold and also convenient for the placement of the fusion device.

[0019] Embodiment 3: Based on Embodiment 1, refer to Figure 4 The insert 2 is in an arc shape, one end of the insert 2 is a T-block, and the end of the flange of the T-block away from the web is an arc surface; the other end of the insert 2 is an M-shaped structure, the closed end in the middle of the M-shaped structure is connected to the web of the T-block, and the barb structures 202 are respectively located on both sides of the closed end in the middle of the M-shaped structure. The utility model adopts an insert with an overall arc shape on the side surface, which is convenient for entering the atlas; the design of the overall insert is conducive to improving the anti-rotation effect after atlantoaxial fusion.

[0020] Embodiment 4: Based on Embodiment 3, the angle between any of the barb structures 202 and the middle closed end of the M-shaped structure is an arc angle, and the barb structures 202 are bent toward the side away from the middle closed end of the M-shaped structure. The utility model adopts and the barb structure is bent toward the side away from the middle closed end of the M-shaped structure, which is conducive to the extrusion state when the insert enters from the rectangular opening, and the reset of the barb structure after entering the rectangular opening. The gap between the reset barb structure and the middle closed end of the M-shaped structure can prevent the insert from falling out.

[0021] Embodiment 5: Based on Embodiment 3, the rectangular opening 102 is a rectangular stepped hole, which is a three-stage stepped hole. The large end of the three-stage stepped hole is located on the side away from the front support section. The large end and the middle section of the three-stage stepped hole cooperate with the T-block; the small end of the three-stage stepped hole is connected to the inside of the hollow polyhedron. The utility model adopts a rectangular three-stage stepped hole, which can facilitate the T-block to cooperate with the large end and the middle section of the three-stage stepped hole after the insert enters from the rectangular opening.

[0022] Embodiment 6: Based on Embodiment 3, the two parallel closed ends of the M-shaped structure are plug blocks 201, the top of the plug block 201 away from the T-shaped block is sharp, and the bottom surface of the V-shaped groove between the two plug blocks 201 is an arc surface. The utility model adopts two plug blocks with sharp tops away from the T-shaped block to prevent the plug from falling out.

[0023] Embodiment 7: Based on embodiment 6, a through hole 203 is provided in the middle of the web of the T-block, and the through hole 203 is close to the flange of the T-block.

[0024] Embodiment 8: Based on embodiment 6, the insert 2 is inserted from the rear end of the fusion device body 1, and the insert block 201 is inclined upward by 30°. The utility model adopts an insert that is inserted from the rear end of the fusion device body, inclined upward by about 30°, and fixed to the anterior arch / posterior arch of the atlas.

[0025] The above are only preferred implementations of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An atlantoaxial joint fusion device, comprising a fusion device body (1) with a rounded angle, characterized in that: The fusion device body (1) is an elliptical hollow polyhedron, which is divided into a front support section and a rear support section. The front support section is a cone composed of four faces or is streamlined to facilitate the implantation of the fusion device; the rear support section is a rectangular parallelepiped, and an opening groove (101), a rectangular opening (102), and a screw hole (103) are sequentially arranged on the rear end surface of the rear support section from one side to the other side. An insert (2) is arranged in the fusion device body (1), and the insert (2) is tilted upward after passing through the rectangular opening (102), and barb structures (202) are arranged on both sides of the insert (2).

2. The atlantoaxial joint fusion device according to claim 1, characterized in that: The opening groove (101) is an L-shaped structure, and the L-shaped structure can be arranged corresponding to the holding end of the holder.

3. The atlantoaxial joint fusion device according to claim 1, characterized in that: The insert (2) is in an arc shape, one end of the insert (2) is a T-shaped block, and the end of the flange of the T-shaped block away from the web is an arc surface; the other end of the insert (2) is an M-shaped structure, the closed end in the middle of the M-shaped structure is connected to the web of the T-shaped block, and the barb structures (202) are respectively located on both sides of the closed end in the middle of the M-shaped structure.

4. The atlantoaxial joint fusion device according to claim 3, characterized in that: The included angle between any one of the barb structures (202) and the middle closed end of the M-shaped structure is an arc angle, and the barb structures (202) are all bent toward a side away from the middle closed end of the M-shaped structure.

5. The atlantoaxial joint fusion device according to claim 3, characterized in that: The rectangular opening (102) is a rectangular stepped hole, which is a three-stage stepped hole. The large end of the three-stage stepped hole is located on the side away from the front supporting section, and the large end and the middle section of the three-stage stepped hole cooperate with the T-block.

6. The atlantoaxial joint fusion device according to claim 3, characterized in that: The two closed ends arranged in parallel on the M-shaped structure are plug blocks (201), the top of the plug block (201) away from the T-shaped block is sharp, and the bottom surface of the V-shaped groove between the two plug blocks (201) is an arc surface.

7. The atlantoaxial joint fusion device according to claim 6, characterized in that: A through hole (203) is provided in the middle of the web of the T-block, and the through hole (203) is close to the flange of the T-block.

8. The atlantoaxial joint fusion device according to claim 6, characterized in that: The insert (2) enters from the rear end of the fusion device body (1), and the insert block (201) is tilted upward at 30 degrees.

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