A combined pedicle screw

Abstract

The application discloses a combined pedicle screw, which comprises a first screw and a second screw. The first screw comprises a first screw rod and a connecting head arranged on the top of the first screw rod. The first screw rod is provided with a first thread. The connecting head is provided with a receiving groove extending along the axial direction and opening upward. The outer sides of the two side walls of the connecting head are provided with cutting surfaces. The second screw comprises a second screw rod provided with a second thread. The pitch and the rotation direction of the first thread and the second thread are the same. The first screw and the second screw are implanted into the pedicle in a parallel mode. The first screw and the second screw are engaged with each other through the first thread and the second thread. Thus, the first screw is supported by the second screw, the pedicle fixation force is enhanced, the screw loosening is reduced, the cement-related complications are avoided, the intraoperative adjustment and the postoperative disassembly are facilitated, and the operation safety and the operation convenience are improved.

Description

Technical Field

[0001] This application relates to the technical field of orthopedic medical devices, and more particularly to a combined pedicle screw. Background Technology

[0002] Pedicle screw systems are commonly used fixation devices in spinal internal fixation surgery, widely applied in spinal fusion, spinal deformity correction, and spinal trauma repair. Traditional pedicle screws typically involve inserting a single screw into the pedicle and using a connecting rod to achieve segmental fixation of the spinal column.

[0003] However, in patients with severe osteoporosis, due to decreased bone density and damage to the trabecular bone structure, single pedicle screw implantation is prone to insufficient fixation, screw loosening, or even pull-out, thus affecting postoperative stability and fusion results. To improve screw fixation strength in osteoporotic patients, current techniques typically employ bone cement reinforcement, injecting bone cement into the vertebral body to enhance screw holding power. However, bone cement reinforcement still has certain drawbacks in practical application. For example, leakage can easily occur during bone cement injection, leading to complications such as nerve and vascular injury. Furthermore, when screws fail or a second surgery is required, the hardened bone cement can make screw removal difficult, increasing surgical trauma and risks.

[0004] Therefore, existing technologies still lack a pedicle screw fixation structure that can improve fixation stability, reduce screw loosening, and facilitate later disassembly without relying on bone cement. Summary of the Invention

[0005] This application aims to at least partially address one of the technical problems in the related art.

[0006] Therefore, one objective of this application is to propose a combined pedicle screw, in which the second screw supports the first screw, thereby enhancing the pedicle fixation force, reducing screw loosening, avoiding cement-related complications, and facilitating intraoperative adjustment and postoperative disassembly, thus improving surgical safety and ease of operation.

[0007] To achieve the above objectives, a first aspect of this application provides a combined pedicle screw, comprising:

[0008] The first screw includes a first screw rod and a connector head disposed on the top of the first screw rod. The first screw rod is provided with a first thread. The connector head has a receiving groove that extends axially and opens upward. The outer sides of the two sidewalls of the connector head are provided with cutting surfaces.

[0009] The second screw includes a second screw rod, on which a second thread is provided;

[0010] The first and second threads have the same pitch and direction of rotation. The first and second screws are implanted into the pedicle in a parallel manner. The first and second screws mesh with each other through the first and second threads.

[0011] In addition, the combined pedicle screw proposed in this application may also have the following additional technical features:

[0012] In one embodiment of this application, the length of the first screw is greater than the length of the second screw, and the outer diameter of the first screw is greater than the outer diameter of the second screw.

[0013] In one embodiment of this application, the connector head is provided with a circumferential break line, and after the connecting rod fixes the receiving groove, the connector head is broken along the break line.

[0014] In one embodiment of this application, the cutting surfaces are symmetrically arranged on two flat surfaces of the connector.

[0015] In one embodiment of this application, the top of the second screw is provided with an internal hexagonal groove.

[0016] In one embodiment of this application, an indicator line is provided on the first screw;

[0017] When the top of the second screw is flush with the indicator line, the first screw and the second screw are fully engaged.

[0018] To achieve the above objectives, a second aspect of this application provides a pedicle screw fixation system, including a connecting rod and at least two of the above-described combined pedicle screws;

[0019] The connecting rod is fixed in the receiving groove of the connector of the adjacent first screw.

[0020] The combined pedicle screw according to this application has the following beneficial effects:

[0021] 1. By inserting the first and second screws parallel to each other inside the pedicle and using their interlocking threads to form a combined support structure, the second screw provides auxiliary support to the first screw, thereby sharing the load borne by the first screw. This effectively enhances the fixation force of the screws in osteoporotic or damaged vertebrae, significantly reduces the risk of loosening of the first screw, and improves overall fixation stability.

[0022] 2. The first screw of this invention is provided with a receiving groove, which can be quickly fixed with the connecting rod. The cutting surfaces on both sides of the connector head improve the convenience of installation and operation. The break line design can remove excess parts after fixation, reducing the impact of structural protrusion. The overall design takes into account fixation strength, safety, and intraoperative operation flexibility.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 This is a schematic diagram of the overall structure of a combined pedicle screw according to this application;

[0026] Figure 2 This is a schematic diagram of the structure of the first screw in a combined pedicle screw according to this application;

[0027] Figure 3 This is a schematic diagram of the structure of the second screw in a combined pedicle screw according to this application;

[0028] Figure 4 This is a schematic diagram of the installation of a connecting rod for a combined pedicle screw according to this application.

[0029] As shown in the figure: 1. First screw; 11. First screw rod; 12. First thread; 13. Connector; 14. Cutting surface; 15. Break line; 16. Receiving groove; 2. Second screw; 21. Second screw rod; 22. Second thread; 23. Socket hexagonal groove; 3. Connecting rod. Detailed Implementation

[0030] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0031] The following describes a combined pedicle screw according to an embodiment of this application, with reference to the accompanying drawings.

[0032] like Figure 1 As shown, a combined pedicle screw according to an embodiment of this application includes a first screw 1 and a second screw 2 used in cooperation with each other. The two screws are independently implanted into the pedicle and form a linkage locking structure, which together constitute the pedicle anchoring body.

[0033] The first screw 1 includes a first screw 11 and a connector 13 disposed on the top of the first screw 11. The first screw 11 is provided with a first thread 12. The connector 13 has a receiving groove 16 that extends axially and opens upward. The outer sides of the two side walls of the connector 13 are provided with cutting surfaces 14.

[0034] It should be noted that, as Figure 2 As shown, the receiving groove 16 in this embodiment can be U-shaped, with an open upper end for engaging, limiting, or pressing the connecting rod 3.

[0035] The cutting surface 14 is a flat, avoidance structure formed by removing the corners of the outer side wall of the connector 13. It can avoid collisions and interference between the instrument and the connector 13 during the screwing in of the second screw 2, and provide lateral operating space for turning the instrument during the operation.

[0036] The second screw 2 includes a second screw 21, on which a second thread 22 is provided;

[0037] The first thread 12 and the second thread 22 have the same pitch and direction of rotation. The first screw 1 and the second screw 2 are implanted into the pedicle in a parallel manner. The first screw 1 and the second screw 2 mesh with each other through the first thread 12 and the second thread 22.

[0038] In this embodiment, by adopting a thread matching structure with equal pitch and same direction of rotation, the first thread 12 and the second thread 22 can achieve precise engagement and synchronous meshing transmission. The structure of the two screws arranged in parallel can form a double-layer constraint inside the same pedicle bone, which greatly improves the overall holding force and effectively limits the loosening, retraction and micro-movement of the first screw 1 after surgery.

[0039] In one embodiment of this application, such as Figure 1 As shown, the length of the first screw 1 is greater than the length of the second screw 2, and the outer diameter of the first screw 11 is greater than the outer diameter of the second screw 21. It should be noted that in this embodiment, the first screw 1 serves as the main load-bearing fixing screw, undertaking the connection of the connecting rod 3, vertebral repositioning, etc.; the second screw 2 serves as an auxiliary locking screw, used to engage and lock with the first screw 1 to prevent the first screw 1 from loosening.

[0040] In one embodiment of this application, such as Figure 1 As shown, the connector 13 is provided with a circumferential break line 15. After the connecting rod 3 fixes the receiving groove 16, it breaks the connector 13 along the break line 15.

[0041] It should be noted that the break line 15 provided in this embodiment is an annular thinning groove structure surrounding the outer wall of the connector 13, and the number of break lines 15 can be one or more.

[0042] Specifically, after the connecting rod 3 is assembled and locked, and the vertebral body is fixed in the correct position, the excess protruding structure at the upper end of the connecting head 13 can be precisely broken off along the break line 15 to reduce the patient's postoperative foreign body sensation and local irritation.

[0043] In one embodiment of this application, such as Figure 2 As shown, the cutting surface 14 is symmetrically arranged on two flat surfaces of the connector 13.

[0044] Understandably, the cutting surfaces 14 on both sides of the connector 13 allow for smooth operation of the rotating instrument during pedicle surgery, regardless of whether it is inserted from the left or right side, eliminating structural interference when two nails are implanted in parallel, and adapting to the conventional spinal surgery operation path.

[0045] In one embodiment of this application, such as Figure 3 As shown, the top of the second screw 2 is provided with an internal hexagonal slot 23. It should be noted that the internal hexagonal slot 23 is used to adapt to the screwing tool, so that it can be screwed in stably. At the same time, the slot has no exposed protrusions, which ensures that the second screw 2 can be completely inserted into the pedicle bone after implantation, without causing compression or irritation to the surrounding soft tissue.

[0046] In one embodiment of this application, an indicator line may be provided on the first screw 1;

[0047] When the top of the second screw 2 is flush with the indicator line, the first screw 1 and the second screw 2 are fully engaged.

[0048] The indicator line is a visible scale mark or ring mark set on the outer wall of the first screw 11, which can intuitively and quickly judge the engagement status of the two screws, avoid the problem of loose engagement and locking failure due to insufficient screwing, or bone compression damage and screw structure destruction due to excessive screwing, and effectively improve the assembly accuracy and surgical safety during the operation.

[0049] A pedicle screw fixation system, such as Figure 4 As shown, it includes a connecting rod 3 and at least two combined pedicle screws;

[0050] The connecting rod 3 is fixed in the receiving groove 16 of the connector head 13 of the adjacent first screw 1.

[0051] It should be noted that in this embodiment, multiple sets of combined pedicle screws are arranged at intervals along the lesion segment of the spine, and fixed by pre-bent connecting rods 3 to adapt to the physiological curvature of the spine, forming an integrated fixation system to achieve repositioning, correction and stable support of the vertebral body.

[0052] Specifically, when pedicle surgery is required:

[0053] First, the patient was placed in the standard surgical position. After disinfection and draping of the surgical area, the pedicle screw insertion area of ​​the target vertebra was exposed by layer-by-layer incision. The screw insertion point was located based on spinal anatomical landmarks and fluoroscopy. A standard pedicle opening device and reamer were used to prepare the bone channel. The integrity of the bone walls of the pedicle was checked to confirm that the channel was undamaged and there was no risk of cortical perforation. This provided a compliant bone channel for the parallel implantation of the first screw (1) and the second screw (2), ensuring the accuracy of subsequent double screw engagement.

[0054] Select a suitable first screw 1, and use a special screw-holding instrument to hold the top connector 13 of the first screw 1 at its position, and slowly screw it in along the prefabricated pedicle channel. The first screw 1 has a larger overall length and outer diameter of the screw shaft, and is implanted into the main pedicle bone as the main load-bearing structure. After implantation, the connector 13 at the top of the first screw 1 is exposed on the pedicle bone surface. The axially open receiving groove 16 at the upper end of the connector 13 is vertically upward and kept open. At the same time, adjust the indicator line on the outer wall of the first screw 11 to the intraoperative viewing angle to facilitate subsequent engagement and alignment observation.

[0055] Within the same pedicle, a parallel implantation channel is established beside the first screw 1 to ensure that the second screw 2 remains parallel to the first screw 1. A matching second screw 2 is selected, and a medical screwdriver is inserted into the embedded hexagonal slot 23 at the top of the second screw 2. During insertion, the lateral clearance space formed by the symmetrically arranged flat cutting surfaces 14 on both sides of the connector 13 of the first screw 1 completely avoids structural interference between the screwdriver, the screw of the second screw 2, and the side wall of the connector 13, ensuring smooth feeding of the second screw 2 along a parallel path without needing to adjust the position of the main screw, greatly reducing the difficulty of the dual-screw assembly operation.

[0056] Subsequently, the second screw 2 is continuously and evenly screwed in. Because the pitch and direction of the first thread 12 of the first screw 1 and the second thread 22 of the second screw 2 are completely consistent, the threads of the two screws can simultaneously and precisely engage and gradually lock in place. Throughout the operation, the visible indicator line on the first screw 11 is observed. When the top end face of the second screw 2 is screwed in to a position completely flush with the indicator line, the screwing is immediately stopped. At this point, the first thread 12 and the second thread 22 achieve maximum contact and engagement, and the two screws are locked in place. The assembly accuracy meets the standard, which avoids both insufficient screwing leading to loosening of the lock and excessive screwing damaging the pedicle bone.

[0057] After assembly, the smaller second screw 2 is completely embedded in the pedicle bone with no exposed structure, and the first screw 1 is constrained by the thread engagement.

[0058] Furthermore, based on the patient's spinal physiological curvature and the correction requirements of the affected segment, the connecting rod 3 is pre-bent and shaped. The pre-bent connecting rod 3 is then inserted from top to bottom into the axial receiving groove 16 of the adjacent multiple sets of first screw 1 connectors 13. The receiving groove 16 is an upper-opening limiting structure that can precisely limit the connecting rod 3, preventing it from shifting or coming out. The connecting rod 3 is then pressurized and fixed by locking accessories, so that the multiple sets of combined pedicle screws and the connecting rod 3 form an integrated rigid fixation system, completing vertebral body repositioning and spinal segment stabilization support.

[0059] After the connecting rod 3 is locked and fixed, and the vertebral body repositioning position and screw rod position are confirmed by intraoperative fluoroscopy, the first screw 1 connector 13 is shaped and optimized. Using the annular break line 15 set circumferentially on the outer wall of the connector 13, a controllable external force is applied by a special instrument to precisely break and remove the excess protruding structure at the upper end of the connector 13 along the break line 15; the break line 15 is a thinning groove structure, which can ensure that the break position is neat and retain the effective fixing structure at the bottom of the receiving groove 16, without affecting the locking strength of the connecting rod 3.

[0060] This step can effectively reduce the exposed height of the connector 13, reduce the pressure and stimulation on the surrounding soft tissues of the waist and back after surgery, reduce the risk of postoperative pain and tissue adhesion, and improve the patient's postoperative recovery and comfort.

[0061] Finally, the engagement status of all first screws 1 and second screws 2 and the fixed position of connecting rod 3 were checked to confirm that the two screws were not loose or displaced, the screw-rod system was stable and the corrective reduction effect met the standards. The surgical area was thoroughly rinsed and hemostasis was performed. A drainage device was routinely placed, and the muscles, fascia and skin were sutured layer by layer to complete the surgical procedure.

[0062] In summary, this application provides a combined pedicle screw according to its embodiments:

[0063] 1. By inserting the first and second screws parallel to each other inside the pedicle and using their interlocking threads to form a combined support structure, the second screw provides auxiliary support to the first screw, thereby sharing the load borne by the first screw. This effectively enhances the fixation force of the screws in osteoporotic or damaged vertebrae, significantly reduces the risk of loosening of the first screw, and improves overall fixation stability.

[0064] 2. The first screw of this invention is provided with a receiving groove, which can be quickly fixed with the connecting rod. The cutting surfaces on both sides of the connector head improve the convenience of installation and operation. The break line design can remove excess parts after fixation, reducing the impact of structural protrusion. The overall design takes into account fixation strength, safety, and intraoperative operation flexibility.

[0065] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A combined pedicle screw, characterized in that, include: The first screw (1) includes a first screw (11) and a connector (13) disposed on the top of the first screw (11). The first screw (11) is provided with a first thread (12). The connector (13) has a receiving groove (16) that extends axially and opens upward. The outer sides of the two sidewalls of the connector (13) are provided with cutting surfaces (14). The second screw (2) includes a second screw rod (21) on which a second thread (22) is provided; The first thread (12) and the second thread (22) have the same pitch and direction of rotation. The first screw (1) and the second screw (2) are implanted into the pedicle in a parallel manner. The first screw (1) and the second screw (2) mesh with each other through the provided first thread (12) and second thread (22).

2. The combined pedicle screw according to claim 1, characterized in that, The length of the first screw (1) is greater than the length of the second screw (2), and the outer diameter of the first screw (11) is greater than the outer diameter of the second screw (21).

3. The combined pedicle screw according to claim 1, characterized in that, The connector (13) is provided with a circumferential break line (15). After the connecting rod (3) fixes the receiving groove (16), the connector (13) is broken along the break line (15).

4. A combined pedicle screw according to claim 1, characterized in that, The cutting surface (14) is symmetrically arranged on two flat surfaces of the connector (13).

5. A combined pedicle screw according to claim 1, characterized in that, The second screw (2) has an internal hexagonal groove (23) on its top.

6. A combined pedicle screw according to claim 1, characterized in that, The first screw (1) is provided with an indicator line; When the top of the second screw (2) is flush with the indicator line, the first screw (1) and the second screw (2) are fully engaged.

7. A pedicle screw fixation system, characterized in that, Includes a connecting rod (3) and at least two combined pedicle screws as described in any one of claims 1-6; The connecting rod (3) is fixed in the receiving groove (16) of the connector (13) of the adjacent first screw (1).

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