Novel bone cement screw for strengthening and fixing in vertebral pedicle

Abstract

The utility model discloses a novel bone cement screw for strengthening and fixing in a vertebral pedicle. The novel bone cement screw comprises a screw body, a sleeve rod and a push rod. According to the novel bone cement pedicle screw, the bone cement is injected into a pedicle part through a hollow slotted roundabout path, so that the bone cement pedicle is strengthened, and then firm fixation is achieved again after serious osteoporosis or screw loosening. The method not only can solve the problems of insufficient holding force of the screw due to severe osteoporosis and rebuilding after the pedicle screw is loosened, but also can reduce additional economic burden and operative trauma caused by bone grafting in the screw path or extension of a fixed section. According to the bone cement pedicle screw, the bone cement is pressed into the pedicle by adopting a roundabout route, so that the bone cement can be fully compressed in a roundabout long channel to enhance the viscosity and filling degree of the bone cement, and when the bone cement is finally pressed into the bone, the adhesion and fixation between the screw and the bone are stronger and more stable.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, specifically relating to a novel bone cement screw for pedicle screw reinforcement fixation. Background Technology

[0002] Pedicle screw fixation is the most common fixation method in posterior spinal surgery. It is widely used in spinal fractures, degenerative spinal diseases, spinal tumors, and spinal deformities, achieving strong three-column fixation through methods such as distraction, rotation, and compression. However, in patients with osteoporosis, decreased bone quality and fragile bone structure significantly reduce biomechanical stability. Traditional pedicle screws struggle to maintain adequate fixation, leading to screw loosening and pull-out, resulting in internal fixation failure. Subsequently, researchers proposed expandable pedicle screws and cemented pedicle screws. While these can improve fixation strength, the former damages bone and carries a risk of failure; the latter, typically a cannulated pedicle screw with a side hole at the tip, increases fixation strength by releasing bone cement at the screw tip. Since osteoporosis primarily affects cancellous bone quality and has little impact on cortical bone, cemented screws, with their tips located in the cancellous bone portion of the vertebral body, also carry the risk of loosening and pull-out.

[0003] The holding force of pedicle screws mainly relies on the pedicle itself, the narrowed section connecting the vertebral arch and the vertebral body. Its anterior end is located in the posterosuperior part of the vertebral body, short and thick, while its posterior end fuses with the vertebral body, articular processes, transverse processes, and lamina, connecting the anterior and posterior columns of the spine and forming the strongest part of the vertebral body. Screw loosening or pull-out can lead to thickening of the pedicle screw track, making effective fixation difficult with both expandable pedicle screws and existing cemented pedicle screws. In such cases, clinical practice usually involves filling with artificial bone before screw placement, which provides some holding force but carries a very high risk of re-loosening. Furthermore, extending the fixation to increase internal fixation strength undoubtedly increases surgical trauma. The issue of revision fixation after pedicle screw loosening has always been a serious challenge for spinal surgeons. Utility Model Content

[0004] To address the aforementioned technical problems, this invention presents a novel bone cement screw for pedicle screw reinforcement fixation, used for revision fixation after spinal internal fixation failure. This novel bone cement pedicle screw injects bone cement into the pedicle via a hollow, slotted, and circuitous path, achieving bone cement reinforcement of the pedicle and thus restoring strong fixation even in cases of severe osteoporosis or screw loosening. This method not only solves the problems of insufficient screw holding force in severe osteoporosis and revision fixation after pedicle screw loosening, but also reduces the additional economic burden and surgical trauma associated with intra-screw bone grafting or extending the fixation segment.

[0005] This cemented pedicle screw is designed based on a novel fixation concept and working principle. Firstly, it features a completely new fixation concept. The placement trajectory of the pedicle screw is through the pedicle to the vertebral body. The pedicle is cortical bone (high-density bone), while the vertebral body is cancellous bone (low-density bone). Existing cemented screws release cement through an opening at the screw tip, dispersing it in the cancellous bone to enhance fixation. This invention, however, changes the traditional fixation approach, injecting the cement into the cortical portion of the pedicle to achieve strong fixation or for revision fixation after screw loosening. The pedicle is an irregular channel; after the cement is released into the pedicle, it disperses to fill the space between the screw and the pedicle cortex, resulting in less cement usage and higher fixation strength compared to traditional cemented screws. Secondly, this screw releases the cement through a novel working principle. This invention employs a circuitous path to inject the cement into the pedicle. This circuitous path allows for slow release of the cement, avoiding the difficulty in controlling the dosage when the screw side holes are too close together.

[0006] To achieve the above-mentioned technical effects, this utility model will be implemented through the following technical solution:

[0007] A novel bone cement screw for pedicle screw fixation includes: a screw, a sleeve, and a push rod;

[0008] The screw includes a stud and a stub. The stud is a self-tapping stud, and the stub is fixedly connected to the top of the stud. The stud has an inner cavity for injection, and the top of the inner cavity is open. A sleeve is inserted into the inner cavity through the opening. A recessed screwing groove is formed on the opening.

[0009] The sleeve is a hollow tubular structure with open ends, and a push rod is slidably inserted inside;

[0010] The push rod is a rod-shaped structure with a solid bottom end;

[0011] The stud has a meandering groove inside; the meandering groove is a groove-shaped space that is recessed from the inner cavity of the injection cylinder towards the outside of the stud, the bottom of the meandering groove extends to the bottom end of the inner cavity of the injection cylinder, and its length is less than the length of the inner cavity of the injection cylinder; a side hole is provided below the top of the meandering groove, and the side hole penetrates the inside and outside of the stud.

[0012] The screw tail is an internally threaded tube with openings at the top and bottom, and is connected to the inner cavity of the injection chamber; a tail cap is fitted onto the internal thread of the screw tail.

[0013] The bottom of the screw groove is provided with a recessed indicator groove; the indicator groove is collinear with the side hole in the radial direction of the stud and is located above the detour groove, indicating the location of the detour groove.

[0014] Furthermore, a limiting strip is fixedly connected above the bottom of the injection cavity; the limiting strip is a ring structure protruding from the injection cavity into the stud; after the sleeve is inserted into the injection cavity, it is blocked by the limiting strip and does not sink to the bottom of the injection cavity.

[0015] Furthermore, the screw tail has a U-shaped groove extending through both sides, the U-shaped groove extending vertically from the top of the screw tail to the top of the stud; a wedge-shaped groove is formed in the middle of the screw tail, and lifting grooves are formed on both sides below the wedge-shaped groove, the lifting grooves are cylindrical grooves and are formed by indentation from the outer wall of the screw tail;

[0016] Furthermore, the screw groove is an internal hexagonal groove;

[0017] Furthermore, at least two side holes are equally spaced in the same vertical direction on the stud; a flow groove is provided on the outer wall of the stud, the flow groove being a groove to eliminate the external thread forming of the stud; the flow groove is located between two side holes and connects the two side holes;

[0018] Furthermore, each of the push rods of the sleeve is fixedly connected to a handle at its top end;

[0019] Furthermore, the above-mentioned fixation method for a novel bone cement screw used for pedicle screw reinforcement includes the following steps:

[0020] S1: Insertion of cemented pedicle screws;

[0021] S2: Inject bone cement into the sleeve rod, which is inserted into the stud from the tip of the screw tail through the opening of the injection cavity to the limiting strip;

[0022] S3: The push rod is slowly pushed into the sleeve through the opening at the tail end of the sleeve;

[0023] S4: Repeat S2 to S3 until the bone cement screw reinforcement fixation is completed.

[0024] The beneficial effects of this utility model are:

[0025] This bone cement pedicle screw has been redesigned based on a new fixation concept and working principle. Firstly, it features a completely new fixation concept. The placement trajectory of the pedicle screw is through the pedicle to the vertebral body. Unlike existing bone cement screw fixation methods, this invention injects bone cement into the pedicle to achieve strong fixation or for revision fixation. The pedicle is an irregular channel; after the bone cement is released into the pedicle, it diffuses to fill the space between the screw and the pedicle cortex, resulting in less material usage and higher fixation strength compared to traditional bone cement screws.

[0026] Secondly, this screw releases bone cement through a completely new working principle. This invention employs a circuitous path to inject bone cement into the pedicle. Because of this circuitous path, the bone cement is released slowly, thus avoiding the problem of difficult dosage control during injection when the screw's side holes are too close, thereby making the operation safer. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a cross-sectional view of the present invention;

[0029] Figure 2 This is a schematic diagram of the overall structure of this utility model;

[0030] Figure 3 This is the front view of this utility model;

[0031] Figure 4 This is a schematic diagram of the structure of the screw described in this utility model;

[0032] Figure 5 This is a side view of the screw described in this utility model;

[0033] Figure 6 This is the utility model Figure 1 Enlarged schematic diagram of the local structure at point A;

[0034] Figure 7 This is the utility model Figure 2 Enlarged schematic diagram of the local structure at point B;

[0035] Figure 8 This is the utility model Figure 2 Enlarged schematic diagram of the local structure at point C;

[0036] Figure 9 This is the utility model Figure 4 Enlarged schematic diagram of the local structure at point D;

[0037] Figure 10 This is a top view of the screw described in this utility model;

[0038] Figure 11 This is a structural schematic diagram of the screw of this utility model, viewed from the side hole position downwards;

[0039] Figure 12 This is the utility model Figure 1 A magnified view of the local structure at point E in the middle;

[0040] The attached diagram lists the components represented by each number as follows:

[0041] 1-Screw, 2-Stud, 201-Injection cavity, 202-Opening, 203-Tightening groove, 204-Circuiting groove, 205-Side hole, 206-Limiting strip, 207-Flow groove, 3-Screw tail, 301-Indicator groove, 302-U-shaped groove, 303-Wedge-shaped groove, 304-Lifting groove, 4-Sleeve rod, 5-Push rod, 7-Handle. Detailed Implementation

[0042] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0043] Example 1

[0044] Please see Figures 1-12 In this embodiment, a novel bone cement screw for pedicle reinforcement fixation includes: screw 1, sleeve 4, and push rod 5.

[0045] In this embodiment, the screw 1 includes a stud 2 and a screw tail 3. The stud is a self-tapping stud, and the screw tail 3 is fixedly connected to the top of the stud 2. The stud 2 has an injection cavity 201 inside, and the top of the injection cavity 201 has an opening 202. A sleeve 4 is inserted into the injection cavity 201 through the opening 202. A recessed screwing groove 203 is formed on the opening 202.

[0046] In this embodiment, the sleeve rod 4 is a tubular structure with a hollow interior and openings 202 at both ends, and a push rod 5 is slidably inserted inside. The outer diameter of the push rod 5 is smaller than the inner diameter of the sleeve rod 4. The purpose of this is to allow the push rod 5 to slide smoothly while being tightly fitted to the sleeve rod 4 by external force, while preventing bone cement from flowing out through the gap between the push rod 5 and the sleeve rod 4.

[0047] In this embodiment, the push rod 5 is a rod-shaped structure with a solid bottom end. Since the push rod 5 is a structure for pushing bone cement, the bottom end needs to be closed. In order to ensure that the push rod 5 has sufficient strength, the upper part of the bottom end should also be a solid structure so that the push rod 5 as a whole is a solid column structure. However, if the strength is sufficient, in order to save materials, the structure above the bottom end of the push rod 5 can be set as a hollow tubular structure so that the push rod 5 as a whole is a tubular structure with a closed bottom end.

[0048] In this embodiment, a meandering groove 204 is provided inside the stud 2; the meandering groove 204 is a groove-shaped space recessed from the injection cavity 201 toward the outside of the stud 2, the bottom of the meandering groove 204 extends to the bottom end of the injection cavity 201, and its length is less than the length of the injection cavity 201; a side hole 205 is provided below the top of the meandering groove 204, and the side hole 205 penetrates the inside and outside of the stud 2; in this device, the meandering channel formed by the meandering groove 204 and the side hole 205, which meanders from the screw head end to the screw tail end, is the meandering channel of the bone cement in this application. After the bone cement enters the sleeve 4, it is squeezed toward the bottom of the injection cavity 201 by the push rod 5, and then flows through the meandering groove 204 toward the side hole 205, and finally flows out of the screw 1 through the side hole 205;

[0049] In this embodiment, the screw tail 3 is an internally threaded tube with upper and lower openings 202, which is connected to the injection cavity 201, and the bottom of the interior is provided with an inwardly formed indicator groove 301; the indicator groove 301 is collinear with the side hole 205 in the radial direction of the stud 2; the screw tail 3 is internally threaded with a tail cap.

[0050] In this embodiment, the bottom of the screw groove 203 is provided with a recessed indicator groove 301; the indicator groove 301 is collinear with the side hole 205 in the radial direction of the stud 2 and is located above the detour groove 204, indicating the direction of the detour groove 204.

[0051] In this embodiment, a limiting strip 206 is fixedly connected above the bottom of the injection cavity 201; the limiting strip 206 is a ring structure protruding from the injection cavity 201 into the stud 2; after the sleeve 4 is inserted into the injection cavity 201, it is blocked by the limiting strip 206; the function of the limiting strip 206 is to create a gap between the bottom end of the sleeve 4 and the bottom end of the injection cavity 201, allowing bone cement to pass through;

[0052] In this embodiment, the screw tail 3 has a U-shaped groove 302 extending through both sides of it, and the U-shaped groove extends vertically from the top of the screw tail 3 to the top of the stud 2; a wedge-shaped groove 303 is provided in the middle of the screw tail 3, and lifting grooves 304 are provided on both sides below the wedge-shaped groove 303. The lifting grooves 304 are cylindrical grooves and are formed by indentation from the outer wall of the screw tail 3.

[0053] In this embodiment, the screw groove 203 is an internal hexagonal groove; the function of the screw groove 203 is to use a hexagonal wrench to screw the screw 1 through the screw groove 203;

[0054] In this embodiment, at least two side holes 205 are equally spaced in the same vertical direction of the stud 2; a flow groove 207 is provided on the outer wall of the stud 2, the flow groove 207 being a groove to eliminate the external thread forming of the stud 2; the flow groove 207 is located between the two side holes 205 and connects the two side holes 205; the flow groove 207 is a space for the flow of bone cement, preventing the bone cement from being blocked by the screw thread when it flows downward after detouring to the tail end of the screw;

[0055] In this embodiment, the top end of each push rod 5 of the sleeve rod 4 is fixedly connected to a handle 7.

[0056] Example 2

[0057] Please see Figures 1-11 Based on the above embodiment 1, a novel bone cement screw fixation method for pedicle screw reinforcement fixation using the above embodiment 1 specifically includes the following steps:

[0058] S1: Insertion of cemented pedicle screws;

[0059] S2: Fill the inside of the sleeve rod 4 with injected bone cement. The sleeve rod 4 is inserted into the inside of the stud 2 from the top of the screw tail 3 through the opening 202 of the injection cavity 201, and to the limiting strip 206.

[0060] S3: Push rod 5 is slowly pushed into sleeve rod 4 through opening 202 at the tail end of sleeve rod 4;

[0061] S4: Repeat S2 to S3 until the bone cement screw reinforcement fixation is completed.

[0062] Specifically, the detour-like injection process of bone cement is as follows: bone cement is injected into the sleeve 4 and follows the sleeve 4 into the injection cavity 201; as the push rod 5 is pushed in, the bone cement is squeezed and flows downward to the bottom of the injection cavity 201, and further through the detour groove 204, flowing along the detour groove 204 towards the tail end of the stud 2; after flowing to the side hole 205, the bone cement flows out of the stud 2 through the side hole 205; after flowing out of the stud 2, the bone cement flows along the thread of the stud 2 and the flow groove 207.

[0063] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A new type of bone cement screw for pedicle internal fixation, characterized in that, Include: screw, sleeve rod, push rod; The screw includes a threaded stud and a screw tail, the threaded stud is a self-tapping threaded stud, and the screw tail is fixedly connected to the top end of the threaded stud; a push injection cavity is formed in the threaded stud, the push injection cavity is open at the top end, and a sleeve rod is inserted into the push injection cavity through the opening; a recessed screw groove is formed on the opening; The sleeve rod is a tubular structure with a hollow interior and open ends, and a push rod is slidably inserted into the interior; The push rod is a solid rod structure at the bottom end; The threaded stud has a detour groove formed therein; the detour groove is a groove-shaped space recessed from the push injection cavity to the outside of the threaded stud, the bottom of the detour groove extends to the bottom end of the push injection cavity, and the length of the detour groove is less than the length of the push injection cavity; a side hole is formed below the top end of the detour groove, and the side hole penetrates the interior and exterior of the threaded stud; The screw tail is an internally threaded pipe with upper and lower openings, and is in communication with the push injection cavity; a tail cap is sleeved on the internally threaded screw tail; The bottom of the screw groove is recessed and formed with an indication groove; the indication groove is collinear with the side hole in the radial direction of the threaded stud and located above the detour groove, indicating the position of the detour groove.

2. A novel cement screw for internal fixation of pedicle according to claim 1, wherein, A limiting strip is fixedly connected above the bottom of the push injection cavity; the limiting strip is a circular ring structure protruding from the push injection cavity to the interior of the threaded stud; the sleeve rod is blocked by the limiting strip after being inserted into the push injection cavity.

3. A novel cement screw for internal fixation of pedicle according to claim 1, wherein, The screw tail is provided with a U-shaped groove penetrating both sides thereof, the U-shaped groove extends vertically from the top of the screw tail to the top end of the threaded stud; a wedge-shaped groove is formed in the middle of the screw tail, pull grooves are formed on both sides below the wedge-shaped groove, the pull grooves are cylindrical grooves and are recessed and formed inward from the outer wall of the screw tail.

4. A new type of bone cement screw for internal fixation of pedicle according to claim 1, characterized in that, The screw groove is an internal hexagonal groove.

5. A novel cement screw for internal fixation of pedicle according to claim 1, wherein, Not less than two side holes are equally spaced in the same vertical direction of the threaded stud; a flow-through groove is formed on the outer wall of the threaded stud, the flow-through groove is a groove formed by eliminating the external threads of the threaded stud; the flow-through groove is located between and communicates with the two side holes.

6. A novel cement screw for internal fixation of pedicle according to claim 1, wherein, The top end of the sleeve rod and the push rod is fixedly connected with a handle.

Images