Spinal fusion internal fixation system capable of preventing adjacent segment degeneration

Abstract

The utility model discloses a kind of spinal fusion internal fixation systems capable of preventing adjacent segment degeneration, including PEEK stick, CBT screw group, connecting rod, pedicle screw group and connecting piece, CBT screw group is set in the top of pedicle screw group, the top of PEEK stick is fixed with adjacent segment vertebral body by CBT screw group, the bottom of PEEK stick is connected with the top of fusion segment connecting rod by connecting piece, or directly connected with fusion segment nail stick system top double-end screw by fusion segment nail stick system top double-end screw, to realize the connection and fixation of PEEK stick and fusion segment vertebral body nail stick system.The spinal fusion internal fixation system of the utility model has significant superiority compared with prior art in preventing adjacent segment degeneration, improving stability, reducing complication risk, simulating spinal natural curvature and load distribution, allowing certain degree of movement, reducing damage to tissue and providing stronger fixation.

Description

Technical Field

[0001] This utility model relates to the field of orthopedic medical device technology, and in particular to a spinal fusion internal fixation system that can prevent degeneration of adjacent segments. Background Technology

[0002] Spinal fusion surgery aims to treat spinal diseases such as degenerative changes, deformities, fractures, and dislocations, preventing disease progression by stabilizing the spine, reducing pain, and correcting deformities. This surgery uses an internal fixation system consisting of pedicle screws and connecting rods. The screws penetrate the pedicles and are fixed within the vertebral body, connected to metal connecting rods to form a rigid frame that effectively restricts abnormal spinal movement, withstands daily mechanical loads, and prevents further spinal damage or worsening of deformities. However, degeneration of adjacent segments after spinal fusion is a common and challenging complication. Because fusion surgery restricts the natural movement of the spine, adjacent segments may degenerate more rapidly due to increased compensatory activity, potentially leading to new symptoms such as pain and instability, impacting patient prognosis. Therefore, non-fusion techniques have emerged, aiming to achieve spinal stability and functional preservation through a series of devices and techniques, such as dynamic stabilization devices. These techniques not only effectively alleviate patient symptoms but also maintain the natural movement characteristics of the spine to the greatest extent possible, thereby reducing the risk of adjacent segment disease and improving patients' quality of life. Commonly used non-fusion techniques include dynamic stabilization devices, artificial disc replacement, and flexible PEEK rods.

[0003] Common dynamic stabilization devices include the Wallis and Coflex systems. They reduce excessive movement above and below the fusion segment of the spine, decreasing the load on adjacent segments and reducing the risk of degeneration. The Wallis system is an interspinous fixator using a polyetheretherketone (PEEK) spacer that matches the elastic modulus of the posterior lumbar structures, limiting extension and bearing pressure. The Coflex system is a U-shaped titanium alloy structure that is flexible, allowing 50°-100° flexion and extension, enhancing spinal stability, especially rotational stability. Both have their advantages and aim to maintain the physiological activity of the spine. The use of dynamic stabilization devices may lead to complications such as loosening of the internal fixation, spinous process fracture, recurrence of degenerative diseases, and heterotopic ossification, which may require repeat surgery. Artificial disc replacement is a new method for treating lumbar disc degeneration. It involves implanting an artificial intervertebral disc to replace the diseased area, aiming to restore spinal stability and mobility. Its advantages include preserving most of the original disc function, rapid relief of clinical symptoms, and a low recurrence rate. However, this surgery also has drawbacks such as unstable fixation, increased wear and tear on the artificial intervertebral disc, and potential vertebral instability. Therefore, the application of artificial intervertebral disc replacement surgery has gradually decreased.

[0004] In contrast, dynamic rod fixation can stabilize the lumbar spine while preserving intervertebral movement and reducing the load on adjacent segments. Replacing metal connecting rods with polyetheretherketone (PEEK) connecting rods, whose elastic modulus is close to that of bone, helps reduce stress shielding effects. By allowing a certain degree of movement, PEEK rods help maintain the natural load transfer of the spine and reduce the risk of degeneration in adjacent segments, gradually becoming the mainstream non-fusion technique in clinical practice. However, this technique currently has some limitations that need to be addressed: for example, osteoporotic vertebrae may not provide sufficient holding force for pedicle screws, internal fixation systems may not effectively stabilize the lumbar spine, and the incidence of loosening is significantly increased.

[0005] Given the current trend and shortcomings of PEEK rod application in spinal nonfusion techniques, the development of a novel PEEK rod-based spinal fusion internal fixation system to prevent adjacent segment degeneration is particularly urgent. This system aims to optimize the properties of PEEK material, enhance fixation stability, reduce complications, and preserve the natural movement function of the spine, effectively reducing the risk of adjacent segment degeneration. This innovative technology will meet clinical needs, improve patients' quality of life, and promote technological progress and development in the field of spinal surgery.

[0006] Therefore, there is an urgent need for a spinal fusion internal fixation system that can prevent degeneration of adjacent segments. Utility Model Content

[0007] This invention provides a spinal fusion internal fixation system that can prevent degeneration of adjacent segments, solving the problem that PEEK rod internal fixation systems in osteoporotic vertebrae cannot effectively stabilize the lumbar spine, leading to degeneration of adjacent segments.

[0008] The first aspect of this utility model provides a spinal fusion internal fixation system that can prevent degeneration of adjacent segments, including a PEEK rod, a CBT screw assembly, a connecting rod, a pedicle screw assembly, and a connector. The CBT screw assembly is disposed above the pedicle screw assembly. The top end of the PEEK rod is fixed to the vertebral body of the adjacent segment through the CBT screw assembly. The bottom end of the PEEK rod is connected to the top end of the connecting rod through the connector. The bottom end of the connecting rod is fixed to the vertebral body of the fusion segment through the pedicle screw assembly, so as to realize the parallel connection of the PEEK rod and the connecting rod.

[0009] The spinal fusion internal fixation system for preventing adjacent segment degeneration, preferably, includes a pedicle screw assembly comprising a first pedicle screw assembly and a second pedicle screw assembly, wherein the CBT screw assembly, the first pedicle screw assembly, and the second pedicle screw assembly are arranged sequentially from top to bottom, and the top end of the connecting rod is connected to the first pedicle screw assembly. The CBT screw assembly includes two CBT screws arranged side-by-side, and both the first and second pedicle screw assemblies include two pedicle screws arranged side-by-side. The connector is a domino connector, and the bottom end of the PEEK rod is connected to the middle of the connecting rod via the domino connector, thus achieving side-by-side arrangement of the PEEK rod and the connecting rod.

[0010] The spinal fusion internal fixation system for preventing adjacent segment degeneration is preferably provided in the following manner: the CBT screw group includes two CBT screws arranged in parallel; the pedicle screw group includes two pedicle screws arranged in parallel; the connector is a parallel double-ended screw; and the bottom end of the PEEK rod is connected to the top end of the connecting rod through the parallel double-ended screw, so as to realize that the PEEK rod and the connecting rod are arranged in parallel.

[0011] The second aspect of this utility model provides a spinal fusion internal fixation system that can prevent adjacent segment degeneration, including a PEEK rod, a CBT screw assembly, a connecting rod, and a connector. The CBT screw assembly includes a first CBT screw assembly and a second CBT screw assembly. The top end of the PEEK rod is fixed to the vertebral body of the adjacent segment through the first CBT screw assembly. The bottom end of the PEEK rod is connected to the top end of the connecting rod through the connector. The bottom end of the connecting rod is fixed to the vertebral body of the fusion segment through the second CBT screw assembly, so that the PEEK rod and the connecting rod are arranged longitudinally in a row. The first CBT screw assembly and the second CBT screw assembly each include two CBT screws arranged side by side.

[0012] In the spinal fusion internal fixation system that can prevent adjacent segment degeneration, preferably, the connector is a series double-ended CBT screw, and the bottom end of the PEEK rod is connected to the top end of the connecting rod through the series double-ended CBT screw, so that the PEEK rod and the connecting rod are arranged in a row along the longitudinal direction.

[0013] The beneficial effects are:

[0014] 1. CBT screws can penetrate a thicker layer of cortical bone to enter the vertebral body, providing greater initial stability. By penetrating more cortical bone, CBT screws better resist pull-out forces, thus reducing the risk of loosening. CBT screws can be inserted along the inner wall of the pedicle rather than the outer wall, reducing the risk of penetrating the pedicle cortex and thus reducing nerve injury or other complications. Simultaneously, the denser thread design of CBT screws provides better grip in softer bone, making them more advantageous in patients with osteoporosis, thereby improving the overall stability of the internal fixation system.

[0015] 2. PEEK rods have an elastic modulus similar to that of human cortical bone, which can better simulate the natural curvature and load distribution of the spine, thereby reducing pressure on adjacent unfused segments. Traditional metal materials have too high an elastic modulus, which may cause degeneration of adjacent segments.

[0016] 3. PEEK rods possess a degree of flexibility, enabling them to maintain or restore the normal curvature of the spine while allowing a certain degree of movement to reduce stiffness in adjacent segments. This flexibility reduces additional stress on adjacent vertebrae, helping to maintain normal spinal movement and thus reducing premature degeneration of adjacent segments.

[0017] 4. Traditional pedicle screws may cause problems such as pedicle fracture and nerve damage. However, the CBT screw design of this invention is inserted along the inner wall of the pedicle, reducing the risk of penetrating the pedicle cortex, thereby reducing the possibility of nerve damage or other complications.

[0018] 5. This invention can reduce tissue damage. CBT screws cause less damage to tissues than Coflex screws, which helps reduce postoperative inflammatory response and pain, and promotes patient recovery.

[0019] 6. For areas where traditional pedicle screws are difficult to insert (such as scoliosis, spondylolisthesis, etc.), various combinations of screws and PEEK rods can be used to avoid curved and narrow areas and provide stronger fixation.

[0020] 7. It can be used for revision of traditional internal fixation. The CBT screw entry point is more inward and downward, and the screw's trajectory in the vertebral body mainly passes through the cortical bone area. In revision cases, it can provide more reliable fixation, reduce excessive pressure on the local bone, reduce the risk of screw loosening, and reduce the risk of reoperation failure.

[0021] 8. This utility model is applicable to a variety of surgical procedures, including transforaminal lumbar interbody fusion (TLIF), oblique lateral lumbar interbody fusion (OLIF), posterior lumbar interbody fusion (PLIF), midline lumbar interbody fusion (MIDLIF), and minimally invasive transforaminal lumbar interbody fusion (MISTLIF).

[0022] The spinal fusion internal fixation system of this invention has significant advantages over existing technologies in preventing adjacent segment degeneration, improving stability, reducing the risk of complications, simulating the natural curvature and load distribution of the spine, allowing a certain degree of movement, reducing damage to tissues, and providing stronger fixation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0024] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0025] Figure 3 This is a structural schematic diagram of Embodiment 3 of the present invention.

[0026] In the picture:

[0027] 1. CBT screw; 2. Set screw; 3. PEEK bar; 4. Reset plug; 5. Domino connector;

[0028] 6-1. First pedicle screw; 6-2. Second pedicle screw; 6-3. Third pedicle screw;

[0029] 6-4, fourth pedicle screw; 6-5, fifth pedicle screw; 6-6, sixth pedicle screw;

[0030] 7. Connecting parts; 8. Parallel double-ended screws; 9. Series double-ended CBT screws. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0032] In the description of this utility model, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the system or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the use of terms such as "first," "second," etc., to define components is merely for the convenience of distinguishing the aforementioned components; unless otherwise stated, these terms have no special meaning and should not be construed as indicating or implying relative importance.

[0033] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0034] This invention provides a spinal fusion internal fixation system for preventing adjacent segment degeneration, comprising a PEEK rod, a CBT screw assembly (Cortical Bone Trajectory, CBT), a connecting rod, a pedicle screw assembly, and a connector. The CBT screw assembly is positioned above the pedicle screw assembly. The top end of the PEEK rod is fixed to the adjacent vertebral body via the CBT screw assembly, and the bottom end of the PEEK rod is connected in parallel with the connecting rod of the fusion segment. This spinal fusion internal fixation system offers significant advantages over existing technologies in preventing adjacent segment degeneration, improving stability, reducing the risk of complications, mimicking the natural curvature and load distribution of the spine, allowing a certain degree of movement, reducing tissue damage, and providing stronger fixation.

[0035] The following section uses a spinal fusion internal fixation system that can prevent degeneration of adjacent segments as an example to illustrate the entire technical process in detail.

[0036] Example 1

[0037] like Figure 1 As shown, a spinal fusion internal fixation system for preventing adjacent segment degeneration includes a PEEK rod 3, a CBT screw assembly, a connecting rod 7, a first pedicle screw assembly, a second pedicle screw assembly, and a connector. The CBT screw assembly, the first pedicle screw assembly, and the second pedicle screw assembly are arranged sequentially from top to bottom. The top end of the connecting rod 7 is connected to the first pedicle screw assembly. Each CBT screw assembly includes two parallel CBT screws 1. The first pedicle screw assembly includes a first pedicle screw 6-1 and a second pedicle screw 6-2. The second pedicle screw assembly includes a third pedicle screw 6-3 and a fourth pedicle screw 6-4. The connector is a domino connector 5. The bottom end of the PEEK rod 3 is connected to the middle of the connecting rod 7 via the domino connector 5, thus achieving parallel arrangement of the PEEK rod 3 and the connecting rod 7.

[0038] Among them, the CBT screw 1 is equipped with a set screw 2, and the first pedicle screw 6-1, the second pedicle screw 6-2, the third pedicle screw 6-3, the fourth pedicle screw 6-4, and the domino connector 5 are all equipped with a reset screw plug 4.

[0039] Domino joint combined with cortical bone tracking screw type is mainly suitable for the following situations:

[0040] 1. Preventing degeneration of adjacent segments

[0041] 2. Multi-segmental spinal lesions

[0042] When patients have multi-segmental degenerative spinal diseases, such as multi-segmental disc herniation or spinal stenosis, and require extensive internal fixation and fusion, domino connections can effectively connect multiple fixation segments, providing stable fixation support. It can evenly distribute stress, reduce the load on individual fixation points, and lower the risk of internal fixation failure.

[0043] 3. Correction of complex spinal deformities

[0044] For severe spinal deformities, such as scoliosis and kyphosis, surgical correction often involves multiple vertebrae. Domino connections can help achieve precise fixation and fusion of multiple segments during complex deformity correction procedures. They can better adapt to the irregular shapes of the deformed vertebrae, improving the stability and corrective effect of internal fixation.

[0045] 4. Revision surgery

[0046] In revision surgeries of spinal internal fixation and fusion, the original internal fixation structure may be loose, broken, or have other problems, requiring re-fixation and fusion. Domino connections can serve as an effective connection method, combining with the original fixation system or new internal fixation devices to provide reliable fixation support and promote successful fusion.

[0047] The installation method of a spinal fusion internal fixation system that can prevent adjacent segment degeneration in Example 1 specifically includes the following steps:

[0048] S1: A CBT screw assembly is placed on the adjacent vertebral body segment. A first pedicle screw assembly and a second pedicle screw assembly are placed on the vertebral body segment of the fusion segment. The CBT screw assembly, the first pedicle screw assembly, and the second pedicle screw assembly are arranged sequentially from top to bottom. The CBT screw assembly includes two CBT screws 1 arranged side by side. The first pedicle screw assembly includes a first pedicle screw 6-1 and a second pedicle screw 6-2. The second pedicle screw assembly includes a third pedicle screw 6-3 and a fourth pedicle screw 6-4.

[0049] S2: Connect the top ends of the two PEEK rods 3 to the CBT screws 1 respectively;

[0050] S3: Connect the top ends of the two connecting rods 7 to the first pedicle screw 6-1 and the second pedicle screw 6-2 respectively;

[0051] S4: Connect the bottom ends of the two PEEK rods 3 to the middle parts of the two connecting rods 7 respectively through the domino connector 5.

[0052] S5: Connect the bottom end of the connecting rod 7 to the third pedicle screw 6-3 and the fourth pedicle screw 6-4.

[0053] Example 2

[0054] like Figure 2 As shown, a spinal fusion internal fixation system for preventing adjacent segment degeneration includes a PEEK rod 3, a CBT screw assembly, a connecting rod 7, a pedicle screw assembly, and a connector. The CBT screw assembly includes two CBT screws 1 arranged side by side. The pedicle screw assembly includes a fifth pedicle screw 6-5 and a sixth pedicle screw 6-6. The connector is a parallel double-ended screw 8. The bottom end of the PEEK rod 3 is connected to the top end of the connecting rod 7 through the parallel double-ended screw 8, so that the PEEK rod 3 and the connecting rod 7 are arranged side by side.

[0055] Among them, the CBT screw 1 is equipped with a set screw 2, and the fifth pedicle screw 6-5, the sixth pedicle screw 6-6, and the parallel double-ended screw 8 are all equipped with a reset screw plug 4.

[0056] Parallel double-ended screws combined with cortical bone tracking screws are mainly suitable for the following situations:

[0057] 1. Preventing degeneration of adjacent segments

[0058] Based on the development of cortical bone screws, a parallel double-ended screw combined with a cortical bone trajectory screw was developed. This combination not only enhances osteoporotic fixation inherent in cortical bone screws but also increases resistance to proximal junction failure.

[0059] 2. Situations requiring multi-plane fixing

[0060] In certain special cases, such as spinal deformity correction and multi-segment fusion, fixation in multiple planes is required. Parallel double-ended screws can provide fixation force in different directions, meeting the needs of multi-plane fixation. They can be used in combination with other internal fixation devices to achieve three-dimensional fixation, improving spinal stability and fusion outcomes.

[0061] The installation method of a spinal fusion internal fixation system that can prevent adjacent segment degeneration in Example 2 specifically includes the following steps:

[0062] S1: A CBT screw assembly is placed on the adjacent vertebral body segment, and a pedicle screw assembly is placed on the vertebral body segment of the fusion segment. The CBT screw assembly is positioned above the pedicle screw assembly. The CBT screw assembly includes two CBT screws 1 arranged in parallel. The pedicle screw assembly includes a fifth pedicle screw 6-5 and a sixth pedicle screw 6-6 arranged in parallel.

[0063] S2: Connect the top ends of the two PEEK rods 3 to two parallel CBT screws 1 respectively;

[0064] S3: Connect the bottom ends of the two PEEK rods 3 to the top ends of the two connecting rods 7 respectively through parallel double-ended screws 8;

[0065] S4: Connect the bottom ends of the two connecting rods 7 to the fifth pedicle screw 6-5 and the sixth pedicle screw 6-6 respectively.

[0066] Example 3

[0067] like Figure 3 As shown, a spinal fusion internal fixation system for preventing adjacent segment degeneration includes a PEEK rod 3, a first CBT screw assembly, a second CBT screw assembly, a connecting rod 7, and a connector. The top end of the PEEK rod 3 is fixed to the vertebral body of the adjacent segment via the CBT screw assembly, and the bottom end of the PEEK rod 3 is connected to the top end of the connecting rod 7 via the connector. The bottom end of the connecting rod 7 is fixed to the vertebral body of the adjacent segment via CBT screws 1, so that the PEEK rod 3 and the connecting rod 7 are arranged longitudinally in a row.

[0068] The connector is a series double-ended CBT screw 9. The bottom end of the PEEK rod 3 is connected to the top end of the connecting rod 7 through the series double-ended CBT screw 9, so that the PEEK rod 3 and the connecting rod 7 are arranged in a row along the longitudinal direction.

[0069] The first CBT screw group and the second CBT screw group each include two CBT screws 1 arranged in parallel. The CBT screw 1 is provided with a set screw 2, and the series double-ended screw 9 is provided with a reset plug 4.

[0070] The combination of tandem double-headed cortical bone tracking screws and cortical tracking screws is suitable for the following surgical situations:

[0071] 1. Preventing degeneration of adjacent segments

[0072] 2. Surgery for complex spinal deformities

[0073] Tandem double-ended screws can provide a more flexible fixation method at the deformed site, adapting to different vertebral shapes and angles, and helping to achieve precise deformity correction.

[0074] In some cases of adolescent idiopathic scoliosis with large angles, vertebral rotation, and thoracic deformity, tandem double-ended screws can be used for fixation and adjustment at multiple angles across multiple segments, improving the corrective effect and surgical stability.

[0075] 4. Surgery for spinal fracture with dislocation

[0076] Tandem double-ended screws can function simultaneously at the site of fracture and dislocation, achieving reduction of dislocation and stable fixation of fracture by fixing and traction of the upper and lower vertebrae.

[0077] For unstable fractures and dislocations, tandem double-ended screws can provide stronger resistance to rotation and shear, preventing further displacement of the fracture and aggravation of the dislocation, thus creating favorable conditions for spinal healing and rehabilitation.

[0078] 5. Revision surgery

[0079] Tandem double-ended screws can be used as an effective overhaul method. They can be used in conjunction with the existing internal fixation system or to replace some of the failed screws, thereby improving the stability of the fixation.

[0080] For patients who have undergone multiple spinal surgeries, the anatomical structure of the spine may have changed, making the surgery more challenging. Tandem double-ended screws can be designed and applied in a customized manner to meet complex surgical needs.

[0081] The installation method of a spinal fusion internal fixation system that can prevent adjacent segment degeneration in Example 3 specifically includes the following steps:

[0082] S1: A first CBT screw assembly is inserted into the vertebral body of an adjacent segment, and a connector and a second CBT screw assembly are inserted into the vertebral body of the fused segment. The first CBT screw assembly is located above the tandem double-ended CBT screw 9 and the second CBT screw assembly. Both the first CBT screw assembly and the second CBT screw assembly include two CBT screws 1 arranged in parallel. The connector includes two tandem double-ended CBT screws 9 arranged in parallel.

[0083] S2: Connect the top ends of the two PEEK rods 3 to the first CBT screw group respectively;

[0084] S3: Connect the bottom ends of the two PEEK rods 3 to the top ends of the two connecting rods 7 respectively through series double-ended CBT screws 9;

[0085] S4: Connect the bottom ends of the two connecting rods 7 to the second CBT screw group.

[0086] In addition to the above, domino, parallel, and tandem configurations allow for the combined use of cortical bone tracking screws and traditional pedicle screws to meet the diverse needs of different surgical types and conditions. Domino connectors and parallel double-ended screws allow for the use of four traditional screws combined with two CBT screws; tandem double-ended cortical bone tracking screws allow for the use of six CBT screws.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A spinal fusion internal fixation system for preventing adjacent segment degeneration, characterized in that, The device includes a PEEK rod, a CBT screw assembly, a connecting rod, a pedicle screw assembly, and a connector. The CBT screw assembly is positioned above the pedicle screw assembly. The top end of the PEEK rod is fixed to the vertebral body of the adjacent segment via the CBT screw assembly. The bottom end of the PEEK rod is connected to the top end of the connecting rod via the connector. The bottom end of the connecting rod is fixed to the vertebral body of the fused segment via the pedicle screw assembly, thereby achieving parallel connection of the PEEK rod and the connecting rod.

2. The spinal fusion internal fixation system for preventing adjacent segment degeneration according to claim 1, characterized in that, The pedicle screw assembly includes a first pedicle screw assembly and a second pedicle screw assembly. The CBT screw assembly, the first pedicle screw assembly, and the second pedicle screw assembly are arranged sequentially from top to bottom. The top end of the connecting rod is connected to the first pedicle screw assembly. The CBT screw assembly includes two CBT screws arranged side by side. Both the first pedicle screw assembly and the second pedicle screw assembly include two pedicle screws arranged side by side. The connector is a domino connector. The bottom end of the PEEK rod is connected to the middle part of the connecting rod through the domino connector to achieve the parallel arrangement of the PEEK rod and the connecting rod.

3. The spinal fusion internal fixation system for preventing adjacent segment degeneration according to claim 1, characterized in that, The CBT screw assembly includes two CBT screws arranged in parallel, the pedicle screw assembly includes two pedicle screws arranged in parallel, the connector is a parallel double-ended screw, and the bottom end of the PEEK rod is connected to the top end of the connecting rod through the parallel double-ended screw, so as to realize that the PEEK rod and the connecting rod are arranged in parallel.

4. A spinal fusion internal fixation system for preventing adjacent segment degeneration, characterized in that, The device includes a PEEK rod, a CBT screw assembly, a connecting rod, and a connector. The CBT screw assembly includes a first CBT screw assembly and a second CBT screw assembly. The top end of the PEEK rod is fixed to the vertebral body of the adjacent segment via the first CBT screw assembly. The bottom end of the PEEK rod is connected to the top end of the connecting rod via the connector. The bottom end of the connecting rod is fixed to the vertebral body of the fused segment via the second CBT screw assembly, so that the PEEK rod and the connecting rod are arranged longitudinally in a row. Each of the first and second CBT screw assemblies includes two CBT screws arranged side by side.

5. The spinal fusion internal fixation system for preventing adjacent segment degeneration according to claim 4, characterized in that, The connector is a series double-ended CBT screw. The bottom end of the PEEK rod is connected to the top end of the connecting rod through the series double-ended CBT screw, so that the PEEK rod and the connecting rod are arranged in a row along the longitudinal direction.

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