Hollow self-tapping expandable bone cement screw in vertebral body

Abstract

The hollow self-tapping expandable bone cement screw is characterized in that an inner hole is formed in a screw body in the axial direction of the screw body in a penetrating mode, a plurality of windows are evenly distributed on the periphery of the screw body in the radial direction of the screw body, and the windows communicate with the inner hole; the expansion core is a hollow cylinder, and a plurality of bent strips are evenly arranged on the periphery of the expansion core and matched with the windows. The expansion core and the inner hole are directly provided with a retaining gear shifting structure; the inner core is matched with the rivet body and the expansion core, and the tail end of the inner core is in threaded connection with the tail end of the rivet body. The expansion core of the anchoring nail can form a multi-stage adjusting umbrella-shaped supporting column structure, the opening degree of the expansion core can be adjusted in a multi-gear mode, the anchoring nail can adapt to various sudden change and complex conditions, on the basis that light orthopedic is achieved, bone cement injection and dispersion resistance is reduced, conditions are provided for good dispersion of bone cement, the anchoring range and strength of the hollow nail in a vertebral body are enhanced, and the anchoring effect is good. A stable bearing interface is provided for bone cement, and block mass sedimentation is prevented. Production cost is greatly reduced, and terminal burden of a patient is reduced.

Description

Technical Field

[0001] This invention relates to the field of expandable bone screw technology, and in particular to a hollow, self-tapping, expandable bone cement screw for use within the vertebral body. Background Technology

[0002] Kümmell's disease, also known as delayed post-traumatic vertebral collapse, is a specific type of osteoporotic vertebral compression fracture (OVCF). Its typical characteristics include an asymptomatic period following minor trauma, followed by progressive vertebral collapse, localized kyphosis, and chronic low back pain; some cases also present with neurological dysfunction. The most characteristic radiographic finding is a low-density area within the vertebral body, or the "intravertebral vacuum cleft" (IVC). The prevalence of Kümmell's disease is increasing annually in China's aging population, posing a challenging problem in spinal surgery.

[0003] While traditional PVP / PKP treatments can relieve pain, restore vertebral height in the short term, and fill cleft areas, they present several long-term challenges: displacement and settling of bone cement deposits, especially in cases of "cavitation + osteoporosis"; 1. ineffective correction and reconstruction of vertebral physiological structure; 2. failure to achieve long-term biological healing, leading to vertebral re-collapse or adjacent vertebral fractures; 3. bone cement leakage in some cases causing nerve damage or spinal cord compression. Therefore, an increasing number of studies are exploring combined internal fixation techniques for Kümmell's disease to improve biomechanical stability and long-term outcomes.

[0004] For example, in the existing technology, there is a Chinese authorized invention patent with publication number CN107374717B entitled "A Barbed Expansion Screw Injectable with Bone Cement." When using this expansion screw, after the screw body is implanted into the patient's body, a push rod is inserted from the upper end of the stepped hole and pushed downwards to open the expansion shaft. As the expansion shaft enters the opening hole of the expansion body, it expands the expansion body between the two openings outwards. The outwardly expanding expansion body compresses the barbed expansion plate, causing it to open outwards. A bone cement injection device can be used to inject bone cement into the screw body through the stepped hole. The bone cement enters the bone where the screw body is implanted through the opening formed by the U-shaped expansion groove, increasing the bone's ability to withstand force. The barbed expansion plate effectively prevents the screw from retracting; it is especially suitable for patients with osteoporosis or other conditions where the bone's ability to withstand external forces is low.

[0005] However, during surgery, it was found that: 1. The expansion effect is very limited. Even when the expander is fully inserted, only the free end of the expander bar opens significantly, limited by the length of the expander bar itself. Furthermore, the free end is not fixed, and when obstructed, it cannot form effective anchorage; 2. The manufacturing cost is high. The processing method is very cumbersome, requiring multiple expander bars to be cut from the hollow screw body, resulting in extremely high manufacturing costs. This ultimately burdens the user and is disadvantageous to patients; 3. It is inconvenient to use. This expansion screw only has a single-level expansion function, i.e., once the expander is fully inserted, it forms a single fixed opening mode for the expander bar. In various complex patient situations, such as limited fracture space requiring different degrees of expansion of the expander bar, existing expansion screws are difficult to adapt to these needs. Therefore, there is an urgent need for an expansion screw with stable anchorage, multi-level adjustment, and affordability for patients. Summary of the Invention

[0006] The purpose of this invention is to provide a hollow, self-tapping, expandable bone cement screw within the vertebral body to solve the problems of unstable anchoring, inability to be multi-level adjusted, and unsuitability for patients to consume with existing expansion screws.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A hollow, self-tapping, expandable cemented bone screw for use within the vertebral body, comprising: The nail body has an inner hole that extends through it along its axial direction, and a plurality of windows that are evenly arranged along its radial direction are arranged on the outer periphery of the nail body, and the windows communicate with the inner hole. An expansion core, wherein the expansion core is a hollow cylinder and a plurality of bending strips are evenly arranged on its outer periphery, and the bending strips are adapted to the window; The expansion core and the inner hole are directly provided with a backstop adjustment structure; The inner core is adapted to the nail body and the expansion core, and the tail end of the inner core is threadedly connected to the tail end of the nail body.

[0008] A further technical solution is: the anti-reverse adjustment structure includes a first protrusion disposed in the inner hole and a plurality of second protrusions disposed on the expansion core, wherein the first protrusion and the second protrusions are adapted to each other and are both wedge-shaped.

[0009] A further technical solution is that a threaded section is provided on the outer peripheral wall of the inner core, and the threaded section is provided corresponding to the window.

[0010] A further technical solution is that the bent strip is provided with a narrowing section.

[0011] A further technical solution is that the expansion core is adapted to the push rod.

[0012] A further technical solution is: the push rod is provided with an auxiliary tool adapted to it, the auxiliary tool including a handle, a nut, an inner cylinder and a locking pin, the nut is rotatably installed at the tail end of the handle, the outer wall of the inner cylinder is threadedly connected to the inner wall of the nut, and the inner cylinder is slidably engaged with the inner channel of the handle, the locking pin is symmetrically installed at the tail end of the push rod, and the locking pin is engaged with the tail of the inner cylinder.

[0013] A further technical solution is that the front end of the handle is provided with a threaded post that is adapted to the inner hole.

[0014] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: This invention proposes a hollow, self-tapping, expandable bone cement screw within the vertebral body. The expansion core of this anchor screw can form a multi-level adjustable umbrella-shaped support structure with multiple adjustable opening levels, adapting to various sudden changes and complex situations. While achieving mild orthopedic correction, it also reduces the resistance to bone cement injection and diffusion, providing conditions for good diffusion of bone cement, strengthening the anchoring range and strength of the hollow screw within the vertebral body, providing a stable support interface for bone cement, and preventing mass settlement.

[0015] When the expansion core opens, its own length shortens and the bending strips bulge. The two ends of the bending strips will not move freely, which strengthens the anchoring effect. Even if it is hindered by the opening, its opening method is not affected and it can still open. However, the opening shape of each bending strip is affected, but the overall anchoring effect can still be achieved.

[0016] In terms of manufacturing costs, the anchor body and expansion core are molded separately, reducing the individual processing steps and greatly reducing production costs, thus reducing the burden on patients. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a hollow self-tapping expandable bone cement screw in the vertebral body according to the present invention.

[0018] Figure 2 For the present invention Figure 1 A structural diagram from another perspective.

[0019] Figure 3 This is a schematic diagram of the anti-reverse adjustment structure in this invention.

[0020] Figure 4 This is a schematic diagram of the push rod and auxiliary tools in this invention.

[0021] Reference numerals: 1. Nail body; 11. Window; 2. Expansion core; 21. Bending strip; 22. Second protrusion; 23. Narrowing part; 4. Anti-reverse adjustment structure; 5. Push rod; 6. Auxiliary tool; 7. Handle; 8. Nut; 9. Inner cylinder; 10. Locking post. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example

[0028] This implementation example Figure 1 , Figure 2 and Figure 3 As shown, a hollow self-tapping expandable bone cement screw in the vertebral body includes: a screw body 1, an inner hole through which the screw body 1 is provided along its axial direction, and a plurality of windows 11 arranged radially along the outer periphery of the screw body 1, the windows 11 communicating with the inner hole. Expansion core 2 is a hollow cylinder with multiple bent strips 21 evenly arranged on its outer periphery. The bent strips 21 are adapted to the window 11. The expansion core 2 and the inner hole are directly equipped with a backstop adjustment structure 4; The inner core 3 is adapted to the nail body 1 and the expansion core 2, and the tail end of the inner core 3 is threadedly connected to the tail end of the nail body 1.

[0029] The method of using this anchoring nail is as follows: First, establish a channel through the traditional PVP path and insert a guide wire; Second, insert the nail body 1 of this invention along the guide wire, with the tail of the nail body 1 embedded in the vertebral body; Third, insert the expansion core 2 into the nail body 1 (this step can also be performed first, i.e., pre-install the expansion core 2), requiring the bending strip 21 to be opposite to the window 11; Fourth, use a tool (usually a push rod) to push the expansion core 2 to cause it to expand, i.e., the expansion core 2 shortens the bending strip 21 and bulges out of the window 11, forming an "umbrella-shaped support column", providing a stable support interface for the bone cement, preventing the mass from settling, and playing an anchoring role; Fifth, after the opening is complete, remove the push rod and inject bone cement using the nail body 1 and the existing bone cement injection device; Sixth, after the bone cement is injected, push the inner core 3 into the nail body 1 and complete the threaded connection and fixation between the tail end of the inner core 3 and the tail end of the nail body 1.

[0030] It is worth noting that the expansion core 2 is squeezed and expanded at both ends, and is basically unhindered by external factors. Even if there is an obstruction to the opening of the bending strip 21, the expansion core 2 can still open under compression. The obstruction point of the bending strip 21 may not be fully opened, but it does not affect the overall opening trend of the bending strip 21 and can still achieve the anchoring effect.

[0031] Preferably, the anti-reverse adjustment structure 4 includes a first protrusion disposed in the inner hole and a plurality of second protrusions 22 disposed on the expansion core 2, wherein the first protrusion and the second protrusions 22 are adapted to each other and are both wedge-shaped.

[0032] The degree of expansion (adjustment level) of the expansion core 2 is matched with the number of its multiple second protrusions 22. After the expansion core 2 is pushed to shorten, the second protrusions 22 will press against the first protrusion to prevent the expansion core 2 from rebounding. If the bending strip 21 needs to arch further, it continues to push and shorten the expansion core 2. The new second protrusions 22 will press against the first protrusion to prevent the expansion core 2 from rebounding. In this way, multi-level adjustment is achieved.

[0033] Preferably, the outer peripheral wall of the inner core 3 is provided with a threaded section, which is provided corresponding to the window 11.

[0034] The inner core 3 serves to reinforce the nail body 1. The threaded section on the inner core 3 facilitates the insertion of bone cement and forms a firm fit with the bone cement.

[0035] Preferably, the bent strip 21 is provided with a narrowing portion 23.

[0036] Even at the point where the narrow section 23 is bent, the bent strip 21 on the expansion core 2 arches outward at this point. Example

[0037] Based on the above embodiments, this embodiment, for example Figure 4 As shown, the expansion core 2 is adapted to the push rod 5. The push rod 5 is provided with an auxiliary tool 6 adapted to it. The auxiliary tool 6 includes a handle 7, a nut 8, an inner cylinder 9, and a locking pin 10. The nut 8 is rotatably mounted on the tail end of the handle 7. The outer wall of the inner cylinder 9 is threadedly connected to the inner wall of the nut 8, and the inner cylinder 9 is slidably fitted with the inner channel of the handle 7. The locking pin 10 is symmetrically mounted on the tail end of the push rod 5, and the locking pin 10 is fitted with the tail end of the inner cylinder 9.

[0038] After the nail body 1 of the present invention is implanted, an auxiliary tool 6 is inserted into the inner hole of the nail body 1, and then a push rod 5 is inserted into the inner hole of the auxiliary tool 6. The locking pin 10 at the tail of the push rod 5 engages with the inner cylinder 9 of the auxiliary tool 6. The nut 8 is rotated so that the inner cylinder 9 moves along the handle 7 toward the front end of the nail body 1. The push rod 5 moves forward together and squeezes the expansion core 2. The bending strip 21 is bent and opened by the squeezing force. The bending height and angle of the bending strip 21 are adjusted by the anti-reverse adjustment structure 4 according to the size of the vertebra and the compression deformation. The bone cement guide rod is inserted through the tail end interface of the nail body 1, and bone cement is slowly injected. The bone cement diffuses to the surroundings through the four windows 11 at the front end of the nail body 1. After the bone cement diffusion effect is satisfactory under fluoroscopy, the inner core 3 is inserted and the thread at the tail end of the inner core 3 is matched and tightened with the thread at the tail end of the nail body 1.

[0039] Preferably, the front end of the handle 7 is provided with a threaded post that matches the inner hole of the nail body 1.

[0040] The threaded connection between the threaded post and the inner hole of the nail body 1 stabilizes the handle 7, allowing for better insertion of the push rod 5 and compression expansion core 2. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hollow, self-tapping, expandable bone cement screw for use within the vertebral body, characterized in that, include: The nail body (1) has an inner hole that extends through it along its axial direction. The outer periphery of the nail body (1) has a plurality of windows (11) that are arranged radially thereon. The windows (11) are connected to the inner hole. An expansion core (2) is a hollow cylinder with multiple bent strips (21) evenly arranged on its outer periphery. The bent strips (21) are adapted to the window (11). The expansion core (2) and the inner hole are directly provided with a backstop adjustment structure (4); The inner core (3) is adapted to the nail body (1) and the expansion core (2), and the tail end of the inner core (3) is threadedly connected to the tail end of the nail body (1).

2. The hollow self-tapping expandable bone cement screw in the vertebral body according to claim 1, characterized in that: The anti-reverse adjustment structure (4) includes a first protrusion disposed in the inner hole and a plurality of second protrusions (22) disposed on the expansion core (2), wherein the first protrusion and the second protrusions (22) are adapted to each other and are both wedge-shaped.

3. The hollow self-tapping expandable bone cement screw within the vertebral body according to claim 1, characterized in that: The outer peripheral wall of the inner core (3) is provided with a threaded section, which is provided in correspondence with the window (11).

4. The hollow self-tapping expandable bone cement screw in the vertebral body according to claim 1, characterized in that: The bending strip (21) is provided with a narrowing section (23).

5. The hollow self-tapping expandable bone cement screw in the vertebral body according to claim 1, characterized in that: The expansion core (2) is adapted to the push rod (5).

6. The hollow self-tapping expandable bone cement screw in the vertebral body according to claim 1, characterized in that: The push rod (5) is provided with an auxiliary tool (6) adapted to it. The auxiliary tool (6) includes a handle (7), a nut (8), an inner cylinder (9), and a locking pin (10). The nut (8) is rotatably installed at the tail end of the handle (7). The outer wall of the inner cylinder (9) is threadedly connected to the inner wall of the nut (8), and the inner cylinder (9) slides with the inner channel of the handle (7). The locking pin (10) is symmetrically installed at the tail end of the push rod (5), and the locking pin (10) cooperates with the tail of the inner cylinder (9).

7. The hollow self-tapping expandable bone cement screw in the vertebral body according to claim 6, characterized in that: The front end of the handle (7) is provided with a threaded post that is adapted to the inner hole.

Images