Hollow bone screw for compression fracture

Abstract

The utility model relates to the technical field of bone screws, in particular to a hollow bone screw for compression fracture, which comprises a rod portion formed by extending along a first direction, the outer surface of the rod portion is provided with equidistant threads and gradually-changed-pitch threads, the equidistant threads are arranged at the screwing-in end of the rod portion, and the gradually-changed-pitch threads are closer to the equidistant threads. And the pitch of the gradually-changed-pitch thread is smaller. According to the hollow bone screw for compressing the fracture, the fracture part can be opened in the screwing-in process, and secondary damage caused by pressurization to the fracture part is avoided.

Description

Technical Field

[0001] The utility model relates to a bone screw, in particular to a hollow bone screw used for compression fractures. Background Art

[0002] Bone screws are one of the indispensable instruments in surgical fracture operations. Bone screws can fix steel plates or other fixing devices to bones, and can also hold fractured pieces together. Common bone screws include equidistant bone screws and variable pitch bone screws. Among them, the variable pitch bone screw is shown in the publication number CN217744562U, which is named a compression bone screw. The biggest feature of this type of bone screw is that the closer the thread on the screw is to the end, the larger the pitch is. At the same time, equidistant locking threads are added to the head of the screw. Therefore, this type of screw can achieve both compression and locking functions.

[0003] However, the above-mentioned types of screws are not suitable for compression fractures, which mostly occur in the spine, lumbar spine and other parts, and are fractures caused by compression of longitudinal forces. Therefore, during treatment, bone screws are needed to open the compression fracture site. Based on this, a screw that can open the compression fracture site is needed. Utility Model Content

[0004] In order to overcome the deficiencies in the prior art, the utility model provides a hollow bone screw for compression fractures.

[0005] Technical solution: To achieve the above-mentioned purpose, the utility model provides a hollow bone screw for compression fractures, comprising a rod portion extending along a first direction, wherein the outer surface of the rod portion is provided with equidistant threads and gradient threads, wherein the equidistant threads are arranged at the screw-in end of the rod portion, and the closer the gradient threads are to the equidistant threads, the smaller the pitch of the gradient threads is.

[0006] Preferably, the rod is hollow, and openings communicating with the inner cavity are provided at both ends of the rod.

[0007] Preferably, at least one overflow hole communicating with the inner cavity of the rod is provided on the side wall of the rod.

[0008] Preferably, the equidistant thread and the tapered pitch thread are connected to each other.

[0009] Preferably, a blank section is left between the equidistant thread and the tapered-pitch thread.

[0010] Preferably, the screw-in end of the rod is provided with a self-tapping groove structure, and the self-tapping groove structure includes at least two contact pins arranged in a circumferential array, and the contact pins are curved and triangular.

[0011] Preferably, the inner cavity of the rod is provided with at least one special-shaped section that cooperates with a hexagonal wrench or a box spanner.

[0012] The utility model provides a hollow bone screw for compression fractures, which has at least the following technical effects:

[0013] (1) The thread pitch of the screw thread is smaller as it approaches the end, and the screw thread can expand the compression fracture site during the screw insertion process. Therefore, the screw thread is more suitable for compression fracture applications.

[0014] (2) Although the equidistant threads at the end do not apply pressure to the fracture site and cannot expand or compress the fracture site, they have a good locking function and can fix the bone screw to the fracture site. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the hollow bone screw disclosed in Example 2;

[0016] Figure 2 It is a structural cross-sectional view of the hollow bone screw disclosed in Example 1;

[0017] Figure 3 This is a schematic diagram of the structure of the hollow bone screw disclosed in Example 1.

[0018] In the figure, 1, rod; 2, equidistant thread; 3, gradually variable pitch thread; 4, self-tapping groove structure; 5, contact foot; 6, opening; 7, overflow hole; 8, special-shaped section. DETAILED DESCRIPTION

[0019] The following is combined with Figure 1 To Attachment Figure 3 The principles and features of the present invention are described, and the examples given are only used to explain the present invention, and are not used to limit the scope of the present invention.

[0020] Embodiment 1

[0021] A hollow bone screw for compression fractures comprises a rod 1 extending along a first direction. Two kinds of threads are arranged on the outer surface of the rod 1, namely, an equidistant thread 2 and a tapered thread 3. In order to more accurately describe the positional relationship between the equidistant thread 2 and the tapered thread 3, it is now defined that the end of the rod 1 that is preferentially screwed into the fracture site is the screw-in end, and the equidistant thread 2 is arranged at the screw-in end of the rod 1. The equidistant thread 2 and the tapered thread 3 are connected to each other, and the closer the tapered thread 3 is to the equidistant thread 2, the smaller the pitch of the tapered thread 3 is.

[0022] A self-tapping groove structure 4 is provided at one end of the rod 1 (i.e., the screw-in end), the equidistant thread 2 is close to the self-tapping groove structure 4, and the gradually varying thread 3 is away from the self-tapping groove structure 4. Specifically, the self-tapping groove structure 4 includes three contact pins 5 arranged in a circumferential array, and the contact pins 5 are curved and triangular. In addition, the present structure can also adopt the existing self-tapping groove structure 4.

[0023] The rod 1 is hollow, and openings 6 communicating with the inner cavity are provided at both ends of the rod 1. As required, two overflow holes 7 communicating with the inner cavity of the rod 1 can be provided on the side wall of the rod 1 near the screw-in end. The therapeutic effect of the bone screw can be improved by injecting bone cement into the inner cavity of the rod 1.

[0024] A special-shaped section 8 (the special-shaped section 8 can be a hexagonal section) that cooperates with a hexagonal wrench or a plum blossom wrench is provided at the head end of the rod 1. When installing the bone screw, the hexagonal wrench or the plum blossom wrench is inserted into the special-shaped section 8 and the rod 1 is screwed.

[0025] Embodiment 2

[0026] The difference between this embodiment and the first embodiment is that: in this embodiment, a blank section is left between the equidistant thread 2 and the gradually varying pitch thread 3, that is, the equidistant thread 2 and the gradually varying pitch thread 3 are discontinuous; while in the first embodiment, the equidistant thread 2 and the gradually varying pitch thread 3 are connected to each other, that is, the equidistant thread 2 and the gradually varying pitch thread 3 are continuous and uninterrupted.

[0027] The joint screws disclosed in the above-mentioned first and second embodiments can expand the fracture site during the screwing process to avoid applying pressure to the fracture site and causing secondary damage.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hollow bone screw for compression fractures, characterized in that: The invention comprises a rod (1) extending along a first direction, wherein an outer surface of the rod (1) is provided with an equidistant thread (2) and a gradually variable pitch thread (3), wherein the equidistant thread (2) is provided at a screw-in end of the rod (1), and the closer the gradually variable pitch thread (3) is to the equidistant thread (2), the smaller the pitch of the gradually variable pitch thread (3) is.

2. The hollow bone screw for compression fracture according to claim 1, characterized in that: The rod (1) is hollow, and openings (6) communicating with the inner cavity of the rod (1) are provided at both ends of the rod (1).

3. The hollow bone screw for compression fracture according to claim 2, characterized in that: At least one overflow hole (7) communicating with the inner cavity of the rod part (1) is provided on the side wall of the rod part (1).

4. The hollow bone screw for compression fracture according to any one of claims 2 to 3, characterized in that: The equidistant thread (2) and the gradually varying pitch thread (3) are connected to each other.

5. The hollow bone screw for compression fracture according to any one of claims 2 to 3, characterized in that: A blank section is left between the equidistant thread (2) and the gradually varying pitch thread (3).

6. The hollow bone screw for compression fracture according to claim 4, characterized in that: The screw-in end of the rod (1) is provided with a self-tapping groove structure (4), and the self-tapping groove structure (4) comprises at least two contact pins (5) arranged in a circumferential array, and the contact pins (5) are curved and triangular.

7. The hollow bone screw for compression fracture according to claim 5, characterized in that: The screw-in end of the rod (1) is provided with a self-tapping groove structure (4), and the self-tapping groove structure (4) comprises at least two contact pins (5) arranged in a circumferential array, and the contact pins (5) are curved and triangular.

8. The hollow bone screw for compression fracture according to claim 6 or 7, characterized in that: The inner cavity of the rod portion (1) is provided with at least one special-shaped section (8) that cooperates with a hexagonal wrench or a box spanner.

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