Guided self-centering spinal screw

Abstract

The utility model relates to a kind of guiding self-centering spinal screw, including screw body, its innovation point is at:The screw body has the screw head portion, vertebral body cancellous bone holding portion, pedicle cortical bone holding portion and tool operating portion that are connected as a whole and coaxially arranged, the end of the screw head portion is convex spherical structure, the screw head portion is connected as a whole with vertebral body cancellous bone holding portion by link transition part, the link transition part is provided with the concave circular arc mouth arranged towards the axis direction of screw body. The utility model can bear even, stable extrusion force around in implantation process, and will not occur inclination or deviation, so that it can be implanted into specified nail channel accurately, and will not deviate nail channel axis.

Description

Technical Field

[0001] This utility model relates to a spinal screw, specifically a self-centering spinal screw, and belongs to the field of medical device technology. Background Technology

[0002] Currently, during pedicle screw implantation in clinical surgery, deviation from the pre-drilled path is a common occurrence. If the screw is implanted off-track, it may result in either failure to achieve the desired therapeutic effect or, in severe cases, damage to important nerves and blood vessels.

[0003] Research has revealed the main factors contributing to the above issues: 1. The pedicle bone's central structure is cancellous bone, which is relatively soft, while the surrounding area is cortical bone, which is harder. This bone structure is unfavorable for maintaining the screw's fixation axis during screw insertion. 2. For safety reasons, drill bits are typically not used when pre-drilling the pedicle screw track; instead, open-end tapers and pedicle screw openers are used. These instruments create a flat pedicle screw track, which does not perfectly match the round pedicle screw. 3. Existing spinal screws have a 90° tapered head design. When screwed into the track, they are subjected to bone compression. Due to the unevenness of the bone, the screw is prone to wobbling and deviating from the track axis.

[0004] Therefore, it is necessary to design a spinal screw that can ensure implantation along a predetermined path without deviating from the path axis, thus guaranteeing the accuracy of screw implantation. Utility Model Content

[0005] The purpose of this invention is to provide a self-centering spinal screw that can withstand uniform and stable compressive force during implantation without tilting or shifting, enabling precise implantation into a predetermined screw path and preventing deviation from the screw path axis.

[0006] To achieve the above objectives, the technical solution of this utility model is: a self-centering spinal screw, comprising a screw body, the innovation of which lies in:

[0007] The screw body has a screw head, a vertebral cancellous bone holding part, a pedicle cortical bone holding part, and a tool operating part that are integrated and coaxially arranged.

[0008] The end of the screw head has a convex spherical structure.

[0009] The screw head is connected to the vertebral cancellous bone holding part through a connecting transition part, and the connecting transition part is provided with a concave arc opening arranged in the axial direction of the screw body.

[0010] In the above technical solution, the connecting transition part is provided with a plurality of self-tapping cutting grooves evenly arranged along its circumference. The self-tapping cutting grooves extend to above the thread at the bottom of the vertebral cancellous bone holding part, and the thread at the bottom of the vertebral cancellous bone holding part is adjacent to the connecting transition part.

[0011] In the above technical solution, the groove angle α of the self-tapping cutting groove is an acute angle of 30° to 60°.

[0012] In the above technical solution, the connecting transition part is provided with 2 to 3 self-tapping cutting grooves.

[0013] In the above technical solution, the connecting transition portion is constructed in a tapered shape relative to the vertebral cancellous bone holding portion and the pedicle cortical bone holding portion, and the tapered range is controlled between 3° and 10°.

[0014] In the above technical solution, the diameter of the convex spherical structure at the end of the screw head is Ф1mm~Ф3mm.

[0015] In the above technical solution, the thread on the outer periphery of the vertebral cancellous bone holding part is a single-start thread, and the thread on the outer periphery of the pedicle cortical bone holding part is a double-start thread.

[0016] In the above technical solution, the single-threaded pitch of the vertebral cancellous bone holding part is 1.5mm to 3mm, and the depth is 1mm to 2.5mm; the double-threaded pitch of the pedicle cortical bone holding part is 1.5mm to 3mm, and the depth is 1mm to 2.5mm.

[0017] In the above technical solution, the tail of the tool operating part is a ball head structure, and the ball head structure is provided with a locking thread near the end. The tool operating part has an internal six-hole that forms a positioning connection with the operating instrument.

[0018] In the above technical solution, the radius of the circle containing the concave arc opening is 15mm to 40mm, and its arc angle is 5° to 30°.

[0019] The positive effects of this invention are as follows: When using the self-centering spinal screw of this invention, the screw body has a screw head, a vertebral cancellous bone holding part, a pedicle cortical bone holding part, and a tool operating part that are integrated and coaxially arranged.

[0020] Because the end of the screw head has a convex spherical structure, the overall structure of the screw head is smooth. This effectively avoids the risk of sharp tips damaging nerves and blood vessels during the screw insertion into the pre-drilled path.

[0021] Furthermore, since the screw head is integrated with the vertebral cancellous bone holding part through a connecting transition portion, and the connecting transition portion has a concave arc-shaped opening arranged towards the axial direction of the screw body, when the screw is screwed in, the bone will first contact the starting point of the concave arc-shaped opening. As the cross-sectional diameter of the concave arc-shaped opening gradually increases, the bone is also uniformly squeezed outwards by the concave arc-shaped opening. At this time, the squeezing force around the screw is uniform and stable, so that the screw will not tilt or shift.

[0022] Therefore, during the implantation process, the spinal screw of this invention can withstand uniform and stable compression from the surrounding area without tilting or shifting, enabling it to be accurately implanted into the predetermined screw channel without deviating from the axis of the screw channel. This solves the problem in the prior art where the screw shakes and deviates from the axis of the screw channel due to uneven bone density when it is screwed into the screw channel. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of a specific embodiment of the present invention;

[0024] Figure 2 yes Figure 1 A side view diagram;

[0025] Figure 3 This is a three-dimensional structural diagram of the present invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and the given embodiments, but it is not limited thereto.

[0027] like Figure 1 , 2 As shown in Figures 1 and 3, a self-centering spinal screw includes a screw body 1.

[0028] The screw body 1 has a screw head 11, a vertebral cancellous bone holding part 12, a pedicle cortical bone holding part 13, and a tool operating part 14 that are integrally connected and coaxially arranged.

[0029] The end of the screw head 11 has a convex spherical structure.

[0030] The screw head 11 is connected to the vertebral cancellous bone holding part 12 through the connecting transition part 15. The connecting transition part 15 is provided with a concave arc mouth 16 arranged in the axial direction of the screw body 1.

[0031] Furthermore, such as Figure 2As shown, in order to improve the sharpness of the self-tapping cutting groove, reduce the cutting force when screwing in, and facilitate the control of keeping the screw axis direction unchanged when screwing in, the connecting transition part 15 is provided with a plurality of self-tapping cutting grooves 2 evenly arranged along its circumference. The self-tapping cutting grooves 2 extend above the thread at the bottom of the vertebral cancellous bone holding part 12, and the thread at the bottom of the vertebral cancellous bone holding part 12 is adjacent to the connecting transition part 15. This structure effectively solves the problem in the prior art that the screw stability cannot be well controlled due to the large cutting and screwing force, which leads to a large force when screwing in the screw.

[0032] Furthermore, such as Figure 2 As shown, the groove angle α of the self-tapping cutting groove 2 is an acute angle of 30° to 60°, which reduces the cutting rake angle and further improves the sharpness of the self-tapping cutting groove.

[0033] Furthermore, such as Figure 2 As shown, the connecting transition part 15 is provided with 2 to 3 self-tapping cutting grooves 2. The advantage of this structural design is that it maintains the uniformity of cutting force while improving the stability of cutting force.

[0034] Furthermore, such as Figure 1 As shown, in order to further guide the screw implantation and to gradually change the diameter of the connecting transition part as the screw head is screwed in, so as to make it contact the pre-drilled screw track as early as possible and gradually pressurize the bone of the pre-drilled screw track to improve the initial stability of the screw, the connecting transition part 15 is constructed in a tapered shape relative to the vertebral cancellous bone holding part 12 and the pedicle cortical bone holding part 1, and the tapered range is controlled between 3° and 10°.

[0035] Furthermore, in order to further improve the rationality of the connection, the diameter of the convex spherical structure at the end of the screw head 11 is Ф1mm~Ф3mm.

[0036] Furthermore, such as Figure 1 , 3 As shown, in order to ensure that the screw has a good bonding force at different parts of the pedicle and can strengthen the holding force in the cancellous bone and cortical bone, the thread on the outer periphery of the vertebral cancellous bone holding part 12 is a single-start thread, and the thread on the outer periphery of the pedicle cortical bone holding part 13 is a double-start thread.

[0037] Furthermore, in order to improve the bonding force between different parts, the single-threaded pitch of the vertebral cancellous bone holding part 12 is 1.5mm to 3mm and the depth is 1mm to 2.5mm, and the double-threaded pitch of the pedicle cortical bone holding part 13 is 1.5mm to 3mm and the depth is 1mm to 2.5mm.

[0038] Furthermore, such as Figure 1 ,3 As shown, in order to facilitate the operation of the screw by the operating instrument and to ensure that the tool operating part can form a good lock with the pedicle and ensure the overall stability of the screw fixation, the tail of the tool operating part 14 is a ball head structure, and the ball head structure is provided with a locking thread near the end. The tool operating part 14 has an internal six-hole that forms a positioning connection with the operating instrument.

[0039] Furthermore, in order to make the structure more reasonable and to ensure that the screw can be evenly pressed in all directions, and to ensure that the pressing force around the screw is uniform and stable, so as to further improve the screw from tilting or shifting, the radius of the circle in which the concave arc opening 16 is located is 15mm to 40mm, and its arc angle is 5° to 30°.

[0040] In the specific operation of this invention, because the end of the screw head has a convex spherical structure, the overall structure of the screw head is smooth. This effectively avoids the risk of sharp tips damaging nerves and blood vessels during the screw insertion into the pre-drilled path.

[0041] As the screw is continuously screwed in, the bone initially contacts the starting point of the concave arc opening 16. As the cross-sectional diameter of the concave arc opening gradually increases, the bone is also uniformly compressed outwards by the concave arc opening. At this time, the compressive force around the screw is uniform and stable, and the screw will not tilt or shift.

[0042] Ultimately, the screw can be inserted into the predetermined nail track, and the single-threaded connection of the connecting transition part 15, the vertebral cancellous bone holding part 12, the double-threaded connection of the pedicle cortical bone holding part 13, and the locking thread of the tool operating part 14 can form a high bonding force with different parts of the pedicle, ensuring the overall holding force of the screw and preventing it from deviating from the nail track axis due to shaking.

[0043] Therefore, during the implantation process, the screw of this invention can withstand uniform and stable compression from the surrounding area without tilting or shifting, enabling it to be accurately implanted into the predetermined nail channel without deviating from the axis of the nail channel. This solves the problem in the prior art where the screw shakes and deviates from the axis of the nail channel due to uneven bone density when it is screwed into the nail channel.

[0044] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A self-centering spinal screw, comprising a screw body (1), characterized in that: The screw body (1) has a screw head (11) that is integrally connected and coaxially arranged, a vertebral cancellous bone holding part (12), a pedicle cortical bone holding part (13), and a tool operating part (14). The end of the screw head (11) has a convex spherical structure. The screw head (11) is connected to the vertebral cancellous bone holding part (12) through the connecting transition part (15), and the connecting transition part (15) is provided with a concave arc mouth (16) arranged in the axial direction of the screw body (1).

2. The self-centering spinal screw according to claim 1, characterized in that: The connecting transition part (15) is provided with a plurality of self-tapping cutting grooves (2) evenly arranged along its circumference. The self-tapping cutting grooves (2) extend to the thread above the bottom of the vertebral cancellous bone holding part (12), and the thread at the bottom of the vertebral cancellous bone holding part (12) is adjacent to the connecting transition part (15).

3. The self-centering spinal screw according to claim 2, characterized in that: The groove angle α of the self-tapping cutting groove (2) is an acute angle of 30° to 60°.

4. The self-centering spinal screw according to claim 2, characterized in that: The connecting transition part (15) is provided with 2 to 3 self-tapping cutting grooves (2).

5. The self-centering spinal screw according to claim 1, characterized in that: The connecting transition part (15) is constructed in a tapered shape relative to the vertebral cancellous bone holding part (12) and the pedicle cortical bone holding part (13), and the tapered range is controlled between 3° and 10°.

6. The self-centering spinal screw according to claim 1, characterized in that: The diameter of the convex spherical structure at the end of the screw head (11) is Ф1mm~Ф3mm.

7. The self-centering spinal screw according to claim 1, characterized in that: The thread on the outer periphery of the vertebral cancellous bone holding part (12) is a single-start thread, and the thread on the outer periphery of the pedicle cortical bone holding part (13) is a double-start thread.

8. The self-centering spinal screw according to claim 7, characterized in that: The single-threaded pitch of the vertebral cancellous bone holding part (12) is 1.5mm to 3mm, and the depth is 1mm to 2.5mm. The double-threaded pitch of the pedicle cortical bone holding part (13) is 1.5mm to 3mm, and the depth is 1mm to 2.5mm.

9. The self-centering spinal screw according to claim 1, characterized in that: The tail of the tool operating part (14) is a ball head structure, and a locking thread is provided on the ball head structure near the end. The tool operating part (14) has an internal six-hole that forms a positioning connection with the operating instrument.

10. The self-centering spinal screw according to claim 1, characterized in that: The radius of the circle containing the concave arc opening (16) is 15mm to 40mm, and its arc angle is 5° to 30°.

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