A pedicle screw system

Abstract

The application discloses a pedicle screw system, which comprises a screw expansion sleeve, a screw body, a fixing base, a fastening nut, a fixing rod, a guide cylinder and a bone cement injection device; the screw expansion sleeve is provided with a connecting sheet with a gradient structure and expansion wings with through grooves, can reversely engage with a bone hole, and has good anti-loosening effect. The guide cylinder can realize component positioning and assembly guiding, and can also cooperate with the bone cement injection device to complete preoperative bone cement pre-injection strengthening before the screw body and the fixing base are assembled. The fixing base is provided with a guide plate and a limiting type fixing rod, and assembly positioning is convenient. The pedicle screw system has high fixing strength, is suitable for osteoporosis patients, does not need secondary surgery, is simple in assembly, and has strong clinical practicability.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a pedicle screw system. Background Technology

[0002] In spinal surgery, pedicle screws are the core instruments for vertebral fixation and maintaining spinal stability, and are widely used in the treatment of spinal fractures, herniated discs, scoliosis, and other conditions. However, existing pedicle screw systems have several problems in clinical use related to fixation effectiveness and ease of operation, making it difficult to meet surgical requirements. Existing pedicle screw systems lack an effective "stable fixation" structure. After screw implantation, fixation relies solely on the threaded engagement between the screw shaft and the bone tissue. When patients have osteoporosis or low bone density, screw loosening, displacement, and poor fixation stability are likely to occur. Meanwhile, most existing screw systems do not have the function of pre-injection of bone cement for reinforcement. If the screw fixation strength is found to be insufficient after surgery, a second surgery is required for adjustment, which increases the patient's pain and surgical risks. The connection between the fixation seat and the screw body is mostly a single locking structure, lacking guiding and adjustment components. It is difficult to accurately align the vertebral angle during installation, and the fit gap between the fixation rod and the fixation seat is large, which can easily cause the fixation rod to shift, affecting the overall stability of the spinal fixation. To address the shortcomings of existing pedicle screw systems in terms of fixation stability, preoperative reinforcement, installation guidance, and ease of assembly, this invention combines design concepts such as "expansion interlocking," "preoperative bone cement injection," and "multiple precision guidance" to provide a structurally sound pedicle screw system that overcomes the deficiencies of existing technologies. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a pedicle screw system; To achieve the above objectives, the technical solution adopted by the present invention is as follows: A pedicle screw system includes: a screw expansion sleeve 1, a screw body 2, and a fixation base 3; The screw expansion sleeve 1 includes: a connecting part 11, a plurality of connecting pieces 12 fixedly disposed at the distal end of the connecting part 11, and expansion wing pieces 13 fixedly disposed on both sides of the connecting pieces 12; The proximal end of the connecting part 11 is provided with a threaded connecting hole 111; the connecting piece 12 gradually tilts towards the axis of the connecting part 11 from the proximal end to the distal end, the inner side of the connecting piece 12 is provided with an internal thread, and the width of the connecting piece 12 decreases linearly from the proximal end to the distal end; the thickness of the expansion wing 13 increases linearly from the proximal end to the distal end; a plurality of first through grooves 131 are provided on the side of the expansion wing 13 away from the axis of the connecting part 11, and the first through grooves 131 and the radial direction of the connecting part 11 form an angle with the opening facing the proximal end; The near end of the fixed base 3 is provided with an installation groove, and the two side walls of the fixed base 3 opposite to each other are provided with rod placement grooves 31. The far end of the fixed base 3 is provided with a nail placement hole 32. The installation groove connects the rod placement groove 31 and the nail placement hole 32 respectively. A fastening nut 4 is threadedly connected in the installation groove. A fixed rod 5 is detachably provided in the rod placement groove 31. The screw body 2 includes: a screw head 21 and a threaded shank 22 fixedly disposed at the distal end of the screw head 21; a countersunk groove 211 is provided at the proximal end of the screw head 21; The screw head 21 is set in the mounting groove, and the threaded rod 22 passes through the screw hole 32 and the threaded connection hole 111 in sequence. The threaded rod 22 is provided with an external thread that matches the internal thread, and the threaded rod 22 is threadedly connected to the inner side of the connecting piece 12.

[0004] Furthermore, the cross-section of the connecting piece 12 is arc-shaped.

[0005] Furthermore, the number of connecting pieces 12 is 4-6, and several connecting pieces 12 are arranged in a circular array at the far end of the connecting part 11.

[0006] Furthermore, two guide plates 6 are provided opposite to each other on the near end of the fixed base 3, and a separation groove 61 is opened at the far end of the two guide plates 6 along its circumferential direction. The cross-section of the guide plate 6 is arc-shaped.

[0007] Furthermore, the first through slots 131 are evenly distributed along the length of the expansion vane 13.

[0008] Furthermore, the length of the fixing rod 5 is greater than the diameter of the fixing seat 3.

[0009] Furthermore, it also includes a guide cylinder 7 threaded to the outer surface of the near end of the connecting part 11, and the side wall of the guide cylinder 7 is provided with a second through groove 71 extending along the length direction.

[0010] Furthermore, it also includes a bone cement injection device 8, the injection end of which is detachably disposed in the cavity of the guide tube 7.

[0011] The present invention adopts the above technical solution and has the following technical effects compared with the prior art: The expansion wing forms a toothed unit through the first through groove, and the angle between the first through groove and the radial direction of the connecting part forms a chamfer. When it fits into the inner wall of the bone hole, it can achieve reverse engagement, effectively preventing the screw from loosening proximally. The connecting piece adopts a 4-6 circumferential array distribution, combined with a design where the width decreases linearly from proximal to distal, and superimposed with a gradually changing thickness structure of the expansion wing, ensuring that the expansion process is uniform and controllable, fits the bone hole more tightly, and solves the problem of easy screw displacement in patients with osteoporosis.

[0012] This invention adds a guide cylinder and a bone cement injection device, with a clear division of functions: the guide cylinder can smoothly position the screw expansion sleeve in the bone channel, and at the same time provide a guiding channel for the installation of the bone cement injection device and the fixation seat, avoiding assembly misalignment; moreover, this invention can inject bone cement into the threaded connection hole in advance before inserting the screw body and the fixation seat, realizing preoperative pre-strengthening, and the bone cement fills the gap and solidifies in advance, improving the overall fixation strength from the source, eliminating the need for a second injection after surgery, and greatly reducing surgical risks and patient suffering.

[0013] The guide plate of the fixation base can help adjust the screw implantation angle and guide the tightening nut to tighten precisely. After surgery, the guide plate can be removed through the separation groove by pressing, avoiding damage to surrounding tissues. The length of the fixation rod is greater than the diameter of the fixation base. After installation, the two ends protrude to form a limit, which is locked in conjunction with the tightening nut to build a stable spinal fixation system. The multiple guide structures work together to improve the overall surgical efficiency and internal fixation reliability, and are adapted to the clinical treatment needs of spinal surgery. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the axial structure of the screw expansion sleeve, screw body, and fixing seat during assembly in this invention. Figure 2 This is a top view of the assembly structure of the screw expansion sleeve, screw body, and fixing base in this invention. Figure 3 This is a cross-sectional structural diagram of the screw expansion sleeve, screw body, and fixing base during assembly in this invention. Figure 4 This is a schematic diagram of the axial structure of the screw expansion sleeve in this invention; Figure 5 for Figure 4 A schematic diagram of the left-side structure; Figure 6 This is a schematic diagram of the axial structure of the screw body in this invention; Figure 7 This is a schematic diagram of the axial structure of the screw expansion sleeve, guide cylinder, and fixing seat during assembly in this invention. Figure 8 This is a schematic diagram of the axial structure of the fixed base, guide plate, fixed rod, and fastening nut in this invention; Figure 9 This is a schematic diagram of the axial structure of the screw expansion sleeve, guide cylinder, and bone cement injection device during assembly in this invention. The reference numerals in the attached figures are: 1. Screw expansion sleeve; 11. Connecting part; 111. Threaded connection hole; 12. Connecting piece; 13. Expansion wing; 131. First through groove; 2. Screw body; 21. Screw head; 211. Countersunk groove; 22. Threaded rod; 3. Fixing seat; 31. Rod placement groove; 32. Screw placement hole; 4. Fastening nut; 5. Fixing rod; 6. Guide plate; 61. Separation groove; 7. Guide cylinder; 71. Second through groove; 8. Bone cement injection device. Detailed Implementation

[0015] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0018] Example 1 This embodiment provides a pedicle screw system, including: a screw expansion sleeve 1, a screw body 2, a fixing seat 3, a fastening nut 4, a fixing rod 5, a guide tube 7, and a bone cement injection device 8. The screw expansion sleeve 1 includes a connecting part 11, a connecting piece 12, and an expansion wing 13. The connecting part 11 is a tubular structure, and its proximal threaded connection hole 111 is used to mate with the threaded rod 22 of the screw body 2. The connecting piece 12 is fixed at the distal end of the connecting part 11. In this embodiment, four connecting pieces 12 are selected, and the four connecting pieces 12 are arranged in a circumferential array. The cross-section of each connecting piece 12 is arc-shaped. The arc-shaped structure can adapt to the outer curved surface of the threaded rod 22 to ensure the fit when the thread is screwed in. The connecting piece 12 gradually tilts towards the axis of the connecting part 11 from the proximal end to the distal end, and the width decreases linearly from the proximal end to the distal end. This design allows the connecting piece 12 to gradually open in the opposite direction of tilt when the threaded rod 22 is screwed in. The inner side of the connecting piece 12 is provided with an internal thread, which matches the external thread of the threaded rod 22 to achieve a stable connection between the two.

[0019] The expansion wing 13 is fixed on both sides of each connecting piece 12, and its thickness increases linearly from the proximal end to the distal end. The increasing thickness can improve the structural strength of the distal end of the expansion wing 13. Several first through grooves 131 are opened on the side of the expansion wing 13 away from the axis of the connecting part 11. In this embodiment, the first through grooves 131 are evenly distributed along the length direction of the expansion wing 13 (the first through grooves 131 are designed to form a toothed structure on the outer side of the expansion wing 13, and the wing area between adjacent first through grooves 131 constitutes an independent toothed unit). The first through groove 131 and the radial direction of the connecting part 11 form an angle with the opening facing the proximal end. This angle makes the edge of the first through groove 131 form a chamfer structure facing the proximal end. When the toothed unit on the outer side of the expansion wing 13 fits into the inner wall of the bone hole, the chamfer can form a reverse engagement with the inner wall of the bone hole, preventing the screw from loosening in the proximal direction, significantly improving the fixation and anti-loosening effect, and enhancing the bonding stability between the screw and the bone tissue.

[0020] The guide cylinder 7 is threaded to the proximal outer surface of the connecting part 11. The side wall of the guide cylinder 7 is provided with a second through groove 71 extending along the length direction. The guide cylinder 7 has a dual guiding function: first, it can smoothly insert the screw expansion sleeve 1 into the bone channel to achieve precise positioning; second, its cavity can serve as a guide channel for the installation of the bone cement injection device 8 and the fixation seat 3, ensuring that each component is coaxially aligned.

[0021] The injection end of the bone cement injection device 8 is detachably placed inside the cavity of the guide tube 7. In clinical operation, bone cement needs to be injected into the threaded connection hole 111 by the bone cement injection device 8 before the threaded rod 22 passes through the threaded connection hole 111, the assembly screw body 2 and the fixation seat 3, to complete the preoperative pre-strengthening operation.

[0022] The screw body 2 includes a screw head 21 and a threaded rod 22: the screw head 21 is set in the mounting groove of the fixing seat 3, and the countersunk groove 211 at its proximal end is used to adapt to surgical instruments (such as an Allen wrench) to facilitate the turning of the screw body 2; the threaded rod 22 is fixed at the distal end of the screw head 21, and its external thread matches the internal thread of the connecting piece 12. After the threaded rod 22 passes through the pin hole 32 of the fixing seat 3 and the threaded connection hole 111 of the connecting part 11 in sequence, it achieves a threaded connection with the inner side of the connecting piece 12.

[0023] The fixation base 3 has a hollow structure. The mounting groove at its proximal end is used to accommodate the screw head 21, the fastening nut 4, and the end of the fixing rod 5. The rod placement grooves 31 on both sides are used to place the fixing rod 5, and the pin placement hole 32 at the distal end is used for the threaded rod 22 to pass through. The mounting groove connects the rod placement groove 31 and the pin placement hole 32 respectively. The fastening nut 4 is threadedly connected to the mounting groove. After tightening, it can press against the fixing rod 5 and firmly fix the fixing rod 5 at the connection between the mounting groove and the rod placement groove 31. The fixing rod 5 is detachably set in the rod placement groove 31, and the length of the fixing rod 5 is greater than the diameter of the fixation base 3 (after installation, both ends protrude from the side wall of the fixation base 3, forming a limit with the surrounding bone tissue). Two guide plates 6 are provided opposite to each other on the proximal end of the fixation base 3. The guide plates 6 are integrally formed with the fixation base 3 and have an arc-shaped cross-section. The guide plates 6 can help guide the screwing direction of the fastening nut 4 to ensure that the fastening nut 4 and the thread of the installation groove are precisely matched. The distal ends of the two guide plates 6 are provided with separation grooves 61 along their circumference (separation grooves 61 are preset weak links. After surgery, pressing the proximal side wall of the guide plate 6 will cause the separation groove 61 to break due to stress concentration. The guide plate 6 can be removed without tools to avoid damage to the surrounding tissue).

[0024] Example 2 This embodiment provides an assembly method for the pedicle screw system based on Embodiment 1, and the specific operation is as follows: Step 1: First, screw the guide cylinder 7 onto the outer surface of the proximal end of the connecting part 11 of the screw expansion sleeve 1. Relying on the guiding action of the guide cylinder 7, smoothly send the screw expansion sleeve 1 into the pre-drilled bone channel to complete the positioning of the expansion sleeve. Then, insert the injection end of the bone cement injection device 8 into the cavity of the guide cylinder 7. Before the screw body 2 and the fixing seat 3 are assembled and the threaded rod 22 is inserted into the threaded connection hole 111, start the bone cement injection device 8 and inject bone cement into the threaded connection hole 111 of the connecting part 11. After the injection is completed, remove the bone cement injection device 8.

[0025] Step two: The fixing seat 3 is fitted onto the threaded rod 22 of the screw body 2 through its distal pin hole 32. The fixing seat 3 is pushed axially along the threaded rod 22 until the screw head 21 is fully inserted into the mounting groove of the fixing seat 3, forming a pre-assembled body. Using the guide cylinder 7 as a guide reference, the pre-assembled body is aligned and pushed so that the threaded rod 22 passes through the threaded connection hole 111 of the connecting part 11. Then, a surgical tool (such as an Allen wrench) is inserted into the countersunk groove 211 of the screw head 21, and the screw body 2 is turned, driving the threaded rod 22 to advance towards the distal end of the connecting piece 12. Because the connecting piece 12 is inclined towards the axis of the connecting part 11, the threaded rod 22 generates a radial thrust on the connecting piece 12 when it advances, forcing the connecting piece 12 to move away from the connecting part 11. The connecting part 11 expands in the direction of the axis, and the connecting piece 12 drives the expansion wing pieces 13 on both sides to deform synchronously. It should be noted that the first through groove 131 on the expansion wing piece 13 is preset to form a toothed structure on its outer side, and the first through groove 131 and the connecting part 11 form an angle with the opening facing the proximal end in the radial direction. This angle makes the edge of the first through groove 131 chamfered. During the expansion process, the wing area separated by the first through groove 131 forms an independent toothed unit. As the wing piece expands towards the inner wall of the bone hole, the toothed unit fits into the inner wall of the bone hole. At the same time, the chamfer and the bone tissue form a reverse limit to prevent the screw from loosening proximally after implantation. Until the outer wall of the expansion wing piece 13 (including the toothed structure and the chamfer) is completely attached to the inner wall of the bone hole, the screw body 2 is stopped from being turned.

[0026] Step 3: Place the fixing rod 5 into the rod slot 31 of the fixing seat 3, so that the end of the fixing rod 5 extends into the mounting slot; with the help of the guide plate 6, screw the fastening nut 4 into the mounting slot of the fixing seat 3, and tighten the fastening nut 4 with a surgical tool until the fastening nut 4 presses against the end of the fixing rod 5, so that the fixing rod 5 is firmly fixed in the mounting slot, and the assembly of the pedicle screw is completed.

[0027] During preoperative positioning, the guide plate 6 at the proximal end of the fixation seat 3 can be used to fit the fixation seat 3 against the surface of the vertebra and adjust the position of the fixation seat 3 to ensure accurate implantation. After the fixation seat 3 and the fixation rod 5 are fixed, a pressing force is applied to the side wall at the proximal end of the guide plate 6. The separation groove 61 breaks due to stress concentration, and the guide plate 6 can then be removed.

[0028] Example 3 This embodiment 3 provides the usage process of the pedicle screw system as described in embodiment 1: Step 1: Use a pedicle locator to determine the implantation point and drill a bone hole (the diameter of the bone hole should be adapted to the fit of the toothed structure and the chamfer; the depth should match the length of the threaded rod and the screw expansion sleeve 1 to ensure that the toothed structure and the chamfer can be fully embedded in the inner wall of the bone hole to fully exert the anti-loosening effect).

[0029] Step 2: Assemble the guide tube 7 to the outside of the connecting part 11 of the screw expansion sleeve 1. Using the guide tube 7 as a guide, place the screw expansion sleeve 1 as a whole into the bone tunnel. Then, install the bone cement injection device 8 into the guide tube 7. Before installing the screw body 2 and the fixation seat 3, inject bone cement into the threaded connection hole 111 to complete the preoperative pre-strengthening.

[0030] Step 3: Using a wrench to hold the countersunk groove 211 of the screw head 21, align the pre-assembled screw body 2 and fixing base 3 with the guide cylinder 7, and push them along the guide channel so that the threaded rod 22 passes through the threaded connection hole 111. Turn the screw head 21 clockwise: the threaded rod 22 pushes forward and drives the connecting piece 12 to open. The toothed unit formed by the first through groove 131 on the expansion wing 13 unfolds with the wing. At the same time, the chamfer formed by the radial angle between the first through groove 131 and the connecting part 11 fits into the inner wall of the bone hole together with the toothed unit. The chamfer and the bone tissue form a reverse engagement, preventing the screw from loosening to the proximal end, and completing the initial fixation.

[0031] Step 4: Adjust the insertion angle of the fixing seat 3 by using the guide plate 6 at the near end of the fixing seat 3; if there is a deviation, adjust the guide plate 6 to adjust the fixing seat 3 so that the rod groove 31 is kept in the required direction, and ensure that the axis of the screw body 2 is consistent with the axis of the screw expansion sleeve 1, and then continue to turn the screw head 21 to tighten the fixing seat 3.

[0032] Step 5: Following the steps above, implant other screws in the same segment, place both ends of the fixing rod 5 into the rod placement groove 31 of the adjacent fixing seat 3, guide it with the guide plate 6, and tighten the fastening nut 4 to firmly fix the fixing rod 5 in the rod placement groove 31 and the installation groove, thus forming a spinal fixation system.

[0033] For patients with low bone density, bone cement injected into the threaded connection hole 111 before surgery can fill the assembly gap in advance. After curing, combined with the toothed and chamfered structure of the expansion wing, a dual fixation structure of physical interlocking and bone cement bonding is formed, which eliminates the risk of screw loosening from the root and ensures long-term fixation stability.

[0034] In summary, the expansion wing, in conjunction with the first through groove, forms a toothed interlocking structure that can engage with the bone hole in the opposite direction, effectively preventing loosening. The gradient connecting plate and expansion wing ensure uniform and controllable expansion, making it suitable for patients with osteoporosis. The guide tube serves both positioning and guiding functions, preventing component misalignment during assembly. Bone cement can be pre-injected before assembling the screw body and fixation seat, completing preoperative reinforcement without the need for a second surgery. The fixation seat, combined with the guide plate, fixation rod, and fastening nut, facilitates convenient positioning and locking, resulting in high overall assembly efficiency and strong reliability of spinal fixation.

[0035] The above description of the present invention is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A pedicle screw system, characterized in that, include: Screw expansion sleeve (1), screw body (2), and fixing seat (3); The screw expansion sleeve (1) includes: a connecting part (11), a plurality of connecting pieces (12) fixedly disposed at the far end of the connecting part (11), and expansion wing pieces (13) fixedly disposed on both sides of the connecting pieces (12). The connecting part (11) has a threaded connecting hole (111) at its proximal end; the connecting piece (12) gradually tilts towards the axis of the connecting part (11) from the proximal end to the distal end, and the connecting piece (12) has an internal thread on its inner side, and the width of the connecting piece (12) decreases linearly from the proximal end to the distal end; the thickness of the expansion wing (13) increases linearly from the proximal end to the distal end; a plurality of first through grooves (131) are provided on the side of the expansion wing (13) away from the axis of the connecting part (11), and the first through grooves (131) and the radial direction of the connecting part (11) form an angle with the opening facing the proximal end; The mounting base (3) has a mounting groove at its near end, and rod slots (31) are provided on the two opposite side walls of the mounting base (3). The mounting base (3) has a nail hole (32) at its far end. The mounting groove connects the rod slot (31) and the nail hole (32) respectively. A fastening nut (4) is threaded into the mounting groove. A fixing rod (5) is detachably provided in the rod slot (31). The screw body (2) includes: a screw head (21) and a threaded rod (22) fixedly disposed at the distal end of the screw head (21); a countersunk groove (211) is provided at the proximal end of the screw head (21). The screw head (21) is disposed in the mounting groove, the threaded rod (22) passes through the pin hole (32) and the threaded connection hole (111) in sequence, the threaded rod (22) is provided with an external thread that matches the internal thread, and the threaded rod (22) is threadedly connected to the inner side of the connecting piece (12).

2. The pedicle screw system according to claim 1, characterized in that, The cross-section of the connecting piece (12) is arc-shaped.

3. The pedicle screw system according to claim 1, characterized in that, The number of connecting pieces (12) is 4-6, and a plurality of the connecting pieces (12) are arranged in a circular array at the far end of the connecting part (11).

4. The pedicle screw system according to claim 1, characterized in that, Two guide plates (6) are provided opposite to each other on the near end of the fixed base (3). Separation grooves (61) are opened at the far ends of the two guide plates (6) along their circumferential direction. The cross-section of the guide plate (6) is arc-shaped.

5. A pedicle screw system according to claim 1, characterized in that, The first through groove (131) is evenly distributed along the length direction of the expansion wing (13).

6. A pedicle screw according to claim 1, characterized in that, The length of the fixing rod (5) is greater than the diameter of the fixing seat (3).

7. A pedicle screw system according to claim 1, characterized in that, It also includes a guide cylinder (7) threaded to the near-end outer surface of the connecting part (11), and the side wall of the guide cylinder (7) is provided with a second through groove (71) extending in the length direction.

8. A pedicle screw system according to claim 7, characterized in that, Also includes: Bone cement injection device (8), the injection end of which is detachably disposed in the cavity of the guide tube (7).

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