Spine accelerated fusion type posterior multi-track fixing device

Abstract

The invention provides a spine accelerated fusion type posterior multi-track fixing device, and belongs to the technical field of medical instruments. The device comprises a plurality of anchoring screw units which at least comprise a pedicle screw unit and a cortical bone track screw unit; the connecting rod is used for connecting the tail parts of the plurality of anchoring screw units to form a main fixing frame; and the pressurizing agraffe structure is arranged between the anchoring screw unit and the connecting rod and is used for realizing multi-dimensional fixation of the anchoring screw unit on a coronal plane, a horizontal plane and a sagittal plane. The vertebral pedicle screw unit and the cortical bone track screw unit are integrated through the pressurizing agraffe structure, and the safety and effectiveness of a spine stability reconstruction operation are comprehensively improved. And the biomechanical stability can be improved by improving the internal and intervertebral stress of the internal fixation system, the intervertebral fusion process is accelerated, meanwhile, the screw loosening and postoperative complication risks are reduced, and an innovative device system for spine stability reconstruction is constructed.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a spinal acceleration fusion type posterior multi-track fixation device. Background Technology

[0002] With the aging population and the prevalence of unhealthy lifestyles, the incidence of lumbar degenerative diseases (such as lumbar spinal stenosis and lumbar disc herniation) continues to rise, with a prevalence rate as high as 32% to 68% in people over 65 years of age. The coexistence of osteoporosis or osteopenia with lumbar spine diseases is becoming increasingly common, placing a heavy burden on patients and the medical system.

[0003] Thoracolumbar degeneration can lead to asymmetrical narrowing of the joint spaces, facet joint hyperplasia, osteophyte formation, ligamentum flavum hypertrophy, and spinal canal stenosis, and even vertebral rotation and joint subluxation, resulting in complex clinical and radiological manifestations. Treatment goals focus on relieving symptoms, improving spinal condition and function, restoring spinal stability, and restoring sagittal balance.

[0004] While posterior lumbar fusion is currently the main treatment for degenerative lumbar spine diseases, long-term follow-up reveals complications such as pseudoarthrosis, adjacent vertebral lesions, loss of mobility, and neurovascular injury. Among these, adjacent vertebral lesions are particularly common, as the restricted movement of the fused segment leads to increased load and exacerbated compensatory movements, ultimately accelerating the degeneration of the intervertebral disc and facet joints.

[0005] Pedicle screw fixation devices are a common method for reconstructing spinal stability and restoring spinal alignment during posterior lumbar fusion surgery. While they provide reliable three-column fixation, the implantation process requires extensive dissection of soft tissue and exposure of paraspinal muscles, resulting in significant surgical trauma and a long recovery period. In patients with osteoporosis, decreased bone density weakens the bone-screw interface, leading to a sharp increase in the risk of screw loosening, fixation failure, and reoperation. Related studies have reported loosening rates as high as 12.8% to 25%.

[0006] While alternative devices such as percutaneous pedicle screw fixation offer the advantage of being minimally invasive, they often require additional decompression, and repeated intraoperative fluoroscopy increases radiation exposure for both doctors and patients. Cortical bone tracking screw devices improve biomechanical stability by optimizing the screw trajectory and increasing the contact area with the cortical bone, but their resistance to lateral bending and rotation is inferior to that of pedicle screws.

[0007] Traditional internal fixation devices used in current spinal surgery have revealed a series of problems when dealing with challenges such as osteoporosis, complex lumbosacral diseases, and revision surgeries, including insufficient fixation strength, high risk of screw breakage, large surgical trauma, frequent postoperative complications, long recovery period, and significant limitation of sacroiliac joint function. Summary of the Invention

[0008] In view of the above-mentioned shortcomings of traditional internal fixation devices, this invention provides a posterior multi-track fixation device for accelerated spinal fusion. It integrates pedicle screw units and cortical bone tracking screw units through a pressure hook structure, comprehensively improving the safety and effectiveness of spinal stability reconstruction surgery, especially in complex cases and patients with osteoporosis. It can improve biomechanical stability and accelerate intervertebral fusion by increasing the internal and intervertebral stress of the internal fixation system, while reducing the risk of screw loosening and postoperative complications, thus constructing an innovative device system for spinal stability reconstruction.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A spinal acceleration fusion posterior multi-track fixation device includes: Multiple anchoring screw units, including at least a pedicle screw unit and a cortical bone tracking screw unit; A connecting rod is used to connect the tail ends of multiple anchor screw units to form a main fixing frame; A pressure hook structure is disposed between the anchor screw unit and the connecting rod to achieve multi-dimensional fixation of the anchor screw unit in the coronal, horizontal and sagittal planes.

[0010] Preferably, the head end of the pedicle screw unit and the connecting rod are both pointed screws, and the tail end is both a hook; the head end and the tail end of the cortical bone trajectory screw unit are both pointed screws.

[0011] Preferably, the trajectory of the cortical bone trajectory screw unit is inclined 30–40° caudally and 15–20° medially, with a length of 35 mm and a diameter of 5.5 mm to increase the contact area with the cortical bone.

[0012] Preferably, the pedicle screw unit is 45 mm in length and 6.5 mm in diameter to increase the contact area with the cortical bone.

[0013] Preferably, the thread of the pointed screw at the head end of the pedicle screw unit is a triangular coarse thread with a pitch of 2.0 mm and a thread depth of 1.2 mm.

[0014] Preferably, the threads of the pointed screws at the head and tail ends of the cortical bone trajectory screw unit are rectangular fine threads with a pitch of 1.5 mm and a thread depth of 1.0 mm.

[0015] Preferably, the hook at the tail end of the connecting rod rests on the tail end of the cortical bone tracking screw unit, and the hook at the tail end of the pedicle screw unit rests on the pointed screw at the head end of the connecting rod.

[0016] Preferably, the pressurized hook structure is implemented as follows: the hook hole at the tail end of the pedicle screw unit is inserted into the pointed screw at the head end of the connecting rod to restrict coronal and horizontal plane movement; the connection between the pedicle screw unit and the connecting rod is fixed with a nut for pressurization to restrict sagittal plane movement. The pointed screw end of the cortical bone tracking screw unit is connected to the hook hole at the tail end of the connecting rod to restrict its coronal and horizontal plane movement. The cortical bone tracking screw unit is fixed with a nut at the connection point with the connecting rod to restrict sagittal plane movement.

[0017] Preferably, the connecting rod is made of a biocompatible material.

[0018] Preferably, the biocompatible material is titanium or a cobalt-chromium alloy.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) Improve internal fixation stability and fusion rate: The spinal accelerated fusion posterior multi-track fixation device adopts a pressure hook structure, which improves the stiffness and stability of traditional fixation, reduces the screw loosening rate, and improves the fusion rate, effectively addressing the high failure rate and postoperative loosening problems of traditional fixation.

[0020] (2) Outstanding minimally invasive performance: The structural design of the cortical bone trajectory screw unit in this device brings its entry point close to the midline, reducing soft tissue dissection and damage. Compared to traditional fixation devices, the surgical incision length using this device is shorter, and tissue bleeding is reduced. This indicates that the device minimizes the trauma to the patient caused by the surgery itself, which is beneficial for accelerating the patient's later recovery. Figure 4 As shown, Figure 4 In the left image, the green shaded area represents the exposed area during multi-track screw implantation surgery. In the right image, the red shaded area represents the exposed area during traditional internal fixation device implantation surgery. It is evident that the exposed area is smaller in the accelerated spinal fusion posterior multi-track fixation device surgery, demonstrating its minimally invasive nature.

[0021] (3) Wide range of applications: It is widely applicable to ordinary patients, complex lumbosacral diseases and revision surgeries, especially suitable for patients with osteoporosis. The cortical bone trajectory screw unit enhances the holding force of the bone cortex and reduces the risk of loosening and reoperation. In revision surgery, only the adjacent vertebrae and adjacent vertebral bodies need to be exposed, different trajectory screw units are implanted and stability is enhanced by the use of the pressure hook structure, which reduces the risk of recurrence of adjacent vertebral diseases and surgical trauma.

[0022] (4) Reduce postoperative complications: Postoperative paraspinal muscle degeneration is reduced, the average hospital stay is shortened, long-term complications are reduced, the incidence of adjacent vertebral diseases is reduced, and the prognosis of patients is significantly improved.

[0023] (5) Preservation of sacroiliac joint mobility: This provides a new option for patients who require sacroiliac joint fixation, preserving joint mobility and significantly improving their postoperative quality of life. (6) Accelerating Intervertebral Fusion: The team discovered in clinical practice that multi-track screw fixation technology can accelerate intervertebral fusion. Therefore, a clinical controlled trial was designed and finite element analysis was performed. The results showed that multi-track labor anchoring technology significantly improved the overall stiffness and stress bearing capacity of the internal fixation system. During lumbar spine movement, the system can transfer some stress from the intervertebral fusion area to the internal fixation structure, reducing stress concentration in the fusion device and bone graft material. At the same time, by enhancing system stability, it reduces micromotion of the fusion segment, maintains the stability of the effective stress environment in the intervertebral fusion area, thereby promoting osseointegration, improving the fusion rate, and reducing the risk of pseudoarthrosis. Attached Figure Description

[0024] Figure 1 This is the front view of the application of the present invention; Figure 2 Side view for application of the present invention Figure 3 This is a force analysis diagram of the present invention; Figure 4 This is a schematic diagram of the exposed area during the implantation surgery of the present invention; the green shaded area in the left image represents the exposed area during the implantation surgery of the multi-track screw device. The red shaded area in the right image represents the exposed area during the implantation surgery of a traditional internal fixation device. In the diagram, 1 is the cortical bone tracking screw unit; 2 is the connecting rod; 3 is the pedicle screw unit; and 4 is the pressure nut. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] like Figure 1-3 As shown, the present invention provides a spinal acceleration fusion type posterior multi-track fixation device, comprising: Multiple anchoring screw units, including at least a pedicle screw unit and a cortical bone tracking screw unit; A connecting rod is used to connect the tail ends of multiple anchor screw units to form a main fixing frame; A pressure hook structure is disposed between the anchor screw unit and the connecting rod to achieve multi-dimensional fixation of the anchor screw unit in the coronal, horizontal and sagittal planes.

[0029] In the technical solution provided by this invention, the cortical bone trajectory screw unit 1 and the pedicle screw unit 3 are combined, and the internal fixation stiffness and stability are improved by the pressure hook structure, the screw loosening rate is reduced, and the fusion rate is greatly improved.

[0030] In this invention, the head end of the pedicle screw unit 3 and the connecting rod 2 are both pointed screws, and the tail end is both a hook (the hook has a hole, and the hole is preferably a round hole); the head end and tail end of the cortical bone trajectory screw unit 1 are both pointed screws.

[0031] This technical solution simplifies the assembly process of each screw unit and connecting rod 2, improving fixing reliability and component compatibility. Specifically: The connecting rod 2 and the pedicle screw unit 3 have pointed screws at the head and round holes for the pointed screws to be inserted into the hook at the tail. At the same time, the pointed screws at the head of the connecting rod 2 can also be inserted into the round holes of the hooks of other screw units.

[0032] In this invention, the cortical bone trajectory screw unit 1 has a specific trajectory design. The entry point is located in the cortical bone 2–3 mm below the articular process. Its trajectory is inclined caudally at 30–40° and medially at 15–20°, with a length of 35 mm and a diameter of 5.5 mm, to increase the contact area with the cortical bone. The implantation depth is 90%–95% of the total screw length, ensuring that the contact area between the screw and the vertebral cortical bone is not less than 60% of the screw's surface area. In this technical solution, the specific trajectory design increases the contact area between the screw and the cortical bone, improves biomechanical stability, and is especially suitable for patients with osteoporosis, reducing the risk of loosening.

[0033] In this invention, the pedicle screw unit 3 is 45 mm long and 6.5 mm in diameter to increase the contact area with the cortical bone.

[0034] In this invention, the thread of the pointed screw at the head end of the pedicle screw unit 3 is a triangular coarse thread with a pitch of 2.0 mm and a thread depth of 1.2 mm.

[0035] In this invention, the threads of the pointed screws at the head and tail ends of the cortical bone trajectory screw unit are rectangular fine threads with a pitch of 1.5 mm and a thread depth of 1.0 mm.

[0036] In this invention, the head of the connecting rod 2 is provided with a pointed screw for insertion into the hook hole at the tail of the pedicle screw unit 3. The pointed screw can connect and engage with the round hole in the hook at the tail of the pedicle screw unit 3, thus cooperating with the pressure hook structure to achieve multi-dimensional fixation. In this technical solution, the round hole in the hook of the connecting rod 2 (for insertion of the cortical bone tracking screw unit 1) and the pointed screw (for insertion of the pedicle screw unit 3) are respectively engaged. That is, the hook at the tail end of the connecting rod 2 engages with the tail end of the cortical bone tracking screw unit 1, and the hook at the tail end of the pedicle screw unit 3 engages with the pointed screw at the head end of the connecting rod 2. The pressure nut 4 at the connection of each screw unit provides a three-dimensional constraint structural basis for the screw unit, improving the overall rigidity of the internal fixation. The pressure nut 4 is preferably a hexagonal locking nut with a thread type matching the tail of the anchor screw unit. The tightening torque is 8-12 N·m. By applying pressure with the pressure nut 4, the displacement of the anchor screw unit in the sagittal plane is restricted, thus achieving three-dimensional fixation.

[0037] In this invention, the pressure hook structure is implemented as follows: the pointed screw of the cortical bone tracking screw unit 1 is inserted into the hook hole of the connecting rod 2 to restrict the coronal and horizontal movement of the cortical bone tracking screw unit 1; the pressure nut 4 is tightened from the connection end between the cortical bone tracking screw unit 1 and the connecting rod 2 to restrict the sagittal movement; the hook at the tail end of the pedicle screw unit 3 is inserted into the pointed screw at the head end of the connecting rod 2 to restrict the horizontal and coronal movement; and the pressure nut 4 is tightened from the connection point between the pedicle screw unit 3 and the connecting rod 2 to restrict the sagittal movement. This achieves omnidirectional screw fixation. In this technical solution, the connection between the pressure nut 4, the screw, and the connecting rod 2 achieves two levels of constraint. At the connection point between the screw and the connecting rod 2, the hook hole and the pointed screw restrict the coronal and horizontal movement of the cortical bone tracking screw unit 1 and the pedicle screw 3; the pressure nut 4 restricts the sagittal movement of the two screw units, eliminating the fixation gap, significantly improving the bone-screw interface holding force, and greatly reducing the screw loosening rate. This invention utilizes a pressure hook structure to achieve multi-dimensional fixation of multi-track screws, significantly improving the stability of internal fixation. Each screw unit is implanted into the corresponding vertebral body according to its designed trajectory parameters and is further interconnected through the pressure hook structure to form a complete spinal internal fixation system.

[0038] In this invention, the connecting rod 2 is made of a biocompatible material. This technical solution utilizes biocompatible materials to reduce postoperative rejection and improve patient safety and tolerability.

[0039] In this invention, the biocompatible material is titanium or a cobalt-chromium alloy. This technical solution combines high biocompatibility with excellent mechanical strength, reducing the risk of rejection while ensuring the stability and durability of the internal fixation structure.

[0040] In this invention, titanium alloys such as Ti-6Al-4V and cobalt-chromium alloys such as Co-Cr-Mo are subjected to anodizing treatment, and the oxide layer thickness is 5-10 μm.

[0041] The multi-track fixation device provided by this invention is adapted to the L1–S1 segment of the lumbar spine, with a pedicle width of not less than 8mm and a height of not less than 10mm for the adapted vertebral body. It can be used for complex lumbosacral diseases with osteoporosis (T value ≥ -3.0) and for spinal revision surgery, and has the following technical advantages: (1) Multi-track screw combined fixation device structure: For the first time, a composite fixation device was developed that systematically combines two anchoring units with different tracks, namely pedicle screw unit 3 and cortical bone track screw unit 1, into a single device system through a pressure hook structure. This enhances the holding force at the bone-screw interface and is especially suitable for patients with osteoporosis. Biomechanical studies show that the internal fixation stiffness is improved, the stability is enhanced, and the screw loosening rate is reduced.

[0042] (2) Standardization of screw unit implantation trajectory parameters: Key parameters such as the entry point, angle, and depth of each screw unit implantation have been clarified and optimized. This improves the safety, accuracy, predictability, and repeatability of screw placement, and reduces the risk of neurovascular injury. It also promotes the digitization and standardization of the technique.

[0043] (3) Minimally invasive implantation design and soft tissue protection: The cortical bone trajectory screw unit 1 and pedicle screw unit 3 in the device are designed with entry points near the posterior midline, reducing soft tissue dissection and paravertebral muscle damage. The incision length is shortened, and tissue bleeding is reduced. The degree of paravertebral muscle degeneration is reduced after surgery, which is especially suitable for obese patients and accelerates postoperative recovery.

[0044] (4) Multi-scenario application system of the device: Establish standardized surgical procedures for the spinal accelerated fusion posterior multi-track fixation device in various complex clinical scenarios such as osteoporosis, revision surgery, and complex lumbosacral diseases. Improve surgical adaptability and success rate, shorten hospital stay, and significantly improve patient prognosis.

[0045] (5) Fusion-promoting effect of intervertebral stress: Clinical finite element analysis shows that the spinal accelerated fusion posterior multi-track fixation device can guide part of the stress acting on the intervertebral fusion area to the internal fixation system, thereby reducing stress concentration. At the same time, its enhanced structural stability effectively inhibits abnormal micromovement of the fusion segment, maintains a balanced and effective stress distribution at the intervertebral fusion interface, and accelerates the intervertebral fusion process.

[0046] The above description is merely a preferred embodiment of the present invention. However, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the scope of protection of the present invention.

Claims

1. A spinal accelerated fusion posterior multi- trajectory fixation device, comprising: include: Multiple anchoring screw units, including at least a pedicle screw unit and a cortical bone tracking screw unit; A connecting rod is used to connect the tail ends of multiple anchor screw units to form a main fixing frame; A pressure hook structure is disposed between the anchor screw unit and the connecting rod to achieve multi-dimensional fixation of the anchor screw unit in the coronal, horizontal and sagittal planes.

2. A spinal affixed fusion multi-tract fixation device according to claim 1, wherein, The pedicle screw unit and the connecting rod both have pointed screws at the head end and hooks at the tail end; the cortical bone trajectory screw unit also has pointed screws at both the head and tail ends.

3. A spinal affusion fixation device of the posterior multi- trajectory type according to claim 1, characterized in that, The trajectory of the cortical bone trajectory screw unit is inclined caudally at 30–40° and medially at 15–20°, with a length of 35 mm and a diameter of 5.5 mm to increase the contact area with the cortical bone.

4. A spinal affixed fusion multitrack fixation device according to claim 1, wherein, The pedicle screw unit is 45 mm long and 6.5 mm in diameter to increase the contact area with the cortical bone.

5. A spinal affixing multi-tract fixation device of the accelerated fusion type according to claim 2, wherein, The pointed screw at the head end of the pedicle screw unit has a triangular coarse thread with a pitch of 2.0 mm and a thread depth of 1.2 mm.

6. A spinal affixing multi-tract fixation device of the accelerated fusion type according to claim 2, wherein, The threads of the pointed screws at the head and tail ends of the cortical bone trajectory screw unit are rectangular fine threads with a pitch of 1.5 mm and a thread depth of 1.0 mm.

7. A spinal affixing multi-tract fixation device of the accelerated fusion type according to claim 2, wherein, The hook at the tail end of the connecting rod catches the tail end of the cortical bone tracking screw unit, and the hook at the tail end of the pedicle screw unit catches the pointed screw at the head end of the connecting rod.

8. A spinal affixing multi-tract fixation device of the accelerated fusion type according to claim 7, wherein, The pressurized hook structure is implemented as follows: the hook hole at the tail end of the pedicle screw unit is inserted into the pointed screw at the head end of the connecting rod to restrict coronal and horizontal plane movement; the connection between the pedicle screw unit and the connecting rod is fixed with a nut to restrict sagittal plane movement. The pointed screw end of the cortical bone tracking screw unit is connected to the hook hole at the tail end of the connecting rod to restrict its coronal and horizontal plane movement. The cortical bone tracking screw unit is fixed with a nut at the connection point with the connecting rod to restrict sagittal plane movement.

9. A spinal affusion fusion posterior multi- trajectory fixation device according to any of claims 1-8, wherein, The connecting rod is made of a biocompatible material.

10. The posterior multi-trajectory spinal affixing device of Claim 9, wherein, The biocompatible material is titanium or a cobalt-chromium alloy.

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