A twist-to-click posterior spinal fixation system

Abstract

The application discloses a twist buckle type posterior internal fixation system for a spine, which comprises a pedicle screw, a connecting rod and a nail cap. The pedicle screw is provided with a ball head at one end. The top of the connecting rod is provided with a first protrusion. The nail cap is composed of a nail cap body, a gasket and a stop ring. The nail cap body is provided with a cavity. The gasket is arranged in the cavity and can rotate relative to the cavity. An annular groove is arranged below the gasket. The stop ring is embedded in the annular groove. An inner through groove is formed in the gasket. The connecting rod is slidably connected in the inner through groove. A first outer through groove and a second outer through groove are formed in the nail cap body. The connecting rod is also slidably connected in the first outer through groove or the second outer through groove. A first recess is formed in the groove wall of the first outer through groove. The bottom of the gasket is provided with a spherical groove. The system adopts a twist buckle type locking mode, which can avoid the wrong thread and thread slipping phenomenon during the screw locking, and the locking stroke is short, thereby saving the operation time. The locking limiting and anti-retreating mechanism is designed, and the locking feedback effect is provided, so that the excessive locking during the operation is prevented.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically, to a snap-on posterior spinal fixation system. Background Technology

[0002] Posterior spinal fixation systems are the most commonly used implants in spinal internal fixation surgery. Various posterior spinal reduction and fixation systems originate from different combinations and developments of several basic instruments. Commonly used posterior spinal fixation systems consist of pedicle screws, connecting rods, and locking plugs. The process involves inserting pedicle screws into the vertebral body, placing the connecting rod into the pedicle U-groove, and finally locking the screw head and connecting rod from top to bottom using the locking plug. Threaded locking is the traditional mainstream method, but its drawbacks include the potential for misalignment and stripping during tightening. Multiple turns of the locking plug are time-consuming, and the tightness is difficult to accurately control. In clinical practice, to ensure locking, the plug is often over-tightened, leading to a series of damage problems due to inconsistent locking torque, and even surgical accidents such as breakage of the locking device blocking the plug drive groove and making screw removal impossible. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a snap-lock posterior spinal internal fixation system. This system uses a snap-lock method, which avoids thread misalignment and slippage during threaded locking, and has a short locking stroke, saving surgical time. It is designed with locking limit and anti-retraction mechanisms, and has a locking feedback effect to prevent over-locking during surgery.

[0004] To solve the above-mentioned technical problems, the objective of this invention is achieved as follows: The present invention relates to a button-type posterior spinal internal fixation system, comprising:

[0005] Pedicle screw, one end of which has a ball head;

[0006] A connecting rod, the top of which has a first protrusion extending along its length;

[0007] The nail head that connects the pedicle screw and the connecting rod consists of a nail head body, a washer, and a retaining ring.

[0008] The nail head body has a cavity with its opening facing downwards. The washer is located in the cavity and rotates relative to it. Below the washer is an annular groove formed on the cavity wall. The retaining ring is embedded in the annular groove. The washer has an inner through groove with its opening facing upwards and both ends communicating with the outside. The connecting rod is slidably connected in the inner through groove. The nail head body has a first outer through groove and a second outer through groove, both ends of which communicate with the outside. The connecting rod is also slidably connected in the first outer through groove or the second outer through groove. By rotating the nail head body relative to the washer, the connecting rod can switch positions within the first outer through groove and the second outer through groove. The groove wall of the first outer through groove has a first groove adapted to the first protrusion. The bottom of the washer has a spherical groove for the ball head to be inserted from bottom to top. The spherical groove communicates with the inner through groove.

[0009] The present invention is further configured such that: the retaining ring has an opening and at least one second groove, the second groove has a second protrusion that matches it and is provided on the groove wall of the annular groove; a third protrusion provided on the washer is inserted into the opening.

[0010] The present invention is further configured such that: the ball head is provided with annular teeth for the retaining ring to hold it.

[0011] The invention is further configured such that: the side of the washer is provided with a spring piece, the spring piece is provided with a locking hook, and the side of the nail head body is provided with a locking groove that allows the locking hook to be fitted into the groove when the connecting rod is located in the second external through groove.

[0012] The invention is further configured such that the top of the nail head body has a lever portion for controlling its rotation relative to the washer.

[0013] The present invention is further configured such that the lever part is a non-rotating column shape.

[0014] The present invention is further configured to include a locking device; the locking device has a driving head, and the driving head has a lever groove for the lever part to be fitted into.

[0015] The present invention is further configured such that: the driving head is provided with a guide plate disposed outside the opening of the lever groove.

[0016] In summary, the present invention has the following beneficial effects:

[0017] 1. The button-type posterior spinal internal fixation system involved in this invention, compared with traditional spinal internal fixation implants, mainly consists of a nail head, a screw rod, and a connecting rod. Unlike the threaded locking method of traditional posterior spinal internal fixation systems, it adopts a nail head button-type locking method.

[0018] 2. The screw shaft and screw head are designed as separate parts, which are assembled inside the body during use. This design can reduce tissue irritation caused by the screw shaft when it is screwed into the vertebral body during percutaneous minimally invasive surgery, as well as reduce the skin opening, thereby reducing surgical trauma to the patient and facilitating postoperative recovery.

[0019] 3. The nail head body is designed with a through groove that matches the connecting rod in both locked and unlocked states. The lower end is designed with an annular groove to accommodate the retaining ring. The annular groove has two protrusions, which are used to compress the retaining ring and reduce its size when the retaining ring rotates relative to it, so as to prevent the screw rod from coming out of the nail head. When the nail head rotates relative to the connecting rod, it drives the connecting rod to produce up and down relative movement, causing the nail head to compress the washer and the head of the screw rod, generating deformation and providing locking force.

[0020] 4. Twist screw locking device: This locking method avoids the head breakage problem caused by traditional hex and Torx screwdrivers, and can significantly reduce the occurrence of clinical accidents.

[0021] 5. During the operation, the nail head and connecting rod can be combined and placed on the vertebral screw rod at the same time, reducing the difficulty of rod placement in the traditional method. Alternatively, the nail head and screw rod can be combined first in the traditional method, and then the connecting rod can be passed through the through hole of the nail head with the help of instruments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is an exploded structural diagram of the present invention;

[0024] Figure 3 This is a schematic diagram illustrating the overall structure of the nail head body in this invention;

[0025] Figure 4 yes Figure 3 A structural diagram from another perspective;

[0026] Figure 5 This is a partial structural diagram illustrating the main body of the nail head in this invention;

[0027] Figure 6 This is a schematic diagram illustrating the overall structure of the gasket in this invention;

[0028] Figure 7 This is a schematic diagram illustrating the internal structure of the gasket in this invention;

[0029] Figure 8 This is a schematic diagram illustrating the overall structure of the retaining ring in this invention;

[0030] Figure 9 This is a schematic diagram illustrating the overall structure of the connecting rod in this invention;

[0031] Figure 10This is a schematic diagram illustrating the overall structure of the pedicle screw in this invention;

[0032] Figure 11 This is a schematic diagram illustrating the overall structure of the locking device of the present invention;

[0033] Figure 12 This is a schematic diagram of the structure used in this invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that these descriptions are merely for further illustrating the features and advantages of the present invention, and not for limiting the scope of the patent claims of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments.

[0036] Example 1

[0037] See Figures 1 to 12 As shown, the snap-on posterior spinal fixation system involved in this embodiment includes:

[0038] The pedicle screw 100 has a ball head 101 at one end.

[0039] The connecting rod 200 has a first protrusion 201 extending along its length at its top.

[0040] The pedicle screw 100 and the connecting rod 200 are connected by a pedicle screw cap, which consists of a pedicle screw cap body 300, a washer 400 and a retaining ring 500.

[0041] The nail head body 300 has a cavity 301 with its opening facing downwards. The washer 400 is disposed within the cavity 301 and rotates relative to it. Below the washer 400, there is an annular groove 302 formed on the wall of the cavity 301. The retaining ring 400 is embedded in the annular groove 302. The washer 400 has an inner through groove 401 with its opening facing upwards and both ends communicating with the outside. The connecting rod 200 is slidably connected within the inner through groove 401. The nail head body 300 has a first outer through groove 303 and a second outer through groove 303, both ends of which communicate with the outside. The connecting rod 200 is also slidably connected in the first outer through groove 303 or the second outer through groove 304. By rotating the nail head body 300 relative to the washer 400, the connecting rod 200 can switch positions in the first outer through groove 303 and the second outer through groove 304. The first outer through groove 303 has a first groove 305 adapted to the first protrusion 201 on its groove wall. The bottom of the washer 400 has a spherical groove 402 for the ball head 101 to be inserted from bottom to top. The spherical groove 402 communicates with the inner through groove 401.

[0042] Furthermore, the retaining ring 500 is provided with an opening 501 and two second grooves 502. The second grooves 502 are provided with a second protrusion 306 that matches it and is provided on the groove wall of the annular groove 302. A third protrusion 403 provided on the washer 400 is inserted into the opening 501.

[0043] Furthermore, the ball head 101 is provided with annular teeth (not shown) for the retaining ring 500 to grip.

[0044] Furthermore, the washer 400 has a spring piece 404 on its side, and a locking hook 405 is provided on the spring piece 404. The nail head body 300 has a locking groove 307 on its side, which allows the locking hook 405 to be fitted into the groove when the connecting rod is located in the second external through groove.

[0045] Furthermore, the top of the nail head body 300 has a lever portion 308 for controlling its rotation relative to the washer 400.

[0046] Furthermore, the actuating part 308 is in the shape of a non-rotating column.

[0047] Furthermore, it also includes a locking device 600; the locking device 600 has a drive head 601, on which a lever groove 602 is provided for the lever part 307 to be fitted into.

[0048] Furthermore, the drive head 601 is provided with a guide plate 603 located outside the opening of the lever groove 602.

[0049] In this embodiment, the pedicle screws 100 are first screwed onto the spine in a row. Then, a connecting rod 200 with a number of screw heads equal to the number of pedicle screws 100 is taken. The ball head 101 of each pedicle screw 100 is inserted into the spherical groove 402 of the washer 400 of the corresponding screw head. At this time, the connecting rod 200 is located in the first external groove 303 of the screw head body 300. The connecting rod 200 can be moved and adjusted along its length relative to the screw head body 300, and the ball head 101 can also rotate omnidirectionally within the range of the spherical groove 402. After both are adjusted, the locking device 600 is used to align its upper drive head 601 with the lever part 307 on the screw head body 300, and the lever part 307 is twisted until the screw head body 300 rotates relative to the washer 400, causing the connecting rod 200 to move out of the first external groove 303. The connecting rod 200, which is now located in the second outer through groove 304, moves downward relative to the nail head body 300 and is pressed into the second outer through groove 304 because the groove wall of the second outer through groove 304 does not have a groove for the first protrusion 201 to fit. This causes the connecting rod 200, which is now located in the second outer through groove 304, to be pressed down relative to the nail head body 300 and to apply pressure to the ball head 101. Due to the relative rotation of the nail head body 300, the second protrusion 306 in the annular groove 302 moves accordingly. Because the third protrusion 403 limits the retaining ring 500, the second protrusion 306 separates from the second groove 502 during its movement. The second protrusion 306 squeezes the retaining ring 500 with the opening 501. The retaining ring 500 deforms and shrinks, holding the lower position of the ball head 101. Under the pressure from above and below, the ball head 101 is firmly locked, thereby achieving the effect of locking the pedicle screw 100 and the connecting rod 200 in position with the nail head.

[0050] The elastic locking hook 405, in conjunction with the locking groove 307 on the nail head body 300, serves to provide feedback and prevent slippage when locking.

[0051] The addition of ring teeth is used to improve the meshing effect of the washer when it is compressed and deformed.

[0052] The snap-lock posterior spinal fixation system of this invention, compared to traditional spinal internal fixation implants, mainly consists of a screw cap, a screw rod, and a connecting rod. Unlike the threaded locking method of traditional posterior spinal fixation systems, it adopts a snap-lock locking method for the screw cap. The screw rod and screw cap are designed separately and assembled inside the body during use. This design reduces tissue irritation caused by the screw rod when it is screwed into the vertebral body during percutaneous minimally invasive surgery, and also reduces the size of the skin opening, minimizing surgical trauma and facilitating postoperative recovery. The screw cap body has a through groove that matches the connecting rod in both locked and unlocked states, and an annular groove at the lower end to accommodate a retaining ring. Two retaining rings are designed on the annular groove. The protrusion is used to compress the retaining ring and reduce its size when the retaining ring rotates relative to it, thus preventing the screw rod from dislodging from the screw head. When the screw head rotates relative to the connecting rod, it drives the connecting rod to move up and down relative to each other, causing the screw head to compress the washer and the head of the screw rod, generating deformation and providing locking force. This is a locking device for button screws. This locking method avoids the head breakage problem caused by traditional hexagonal and Torx screwdrivers, which can significantly reduce the occurrence of clinical accidents. During the operation, the screw head and the connecting rod can be combined and placed on the vertebral screw rod at the same time, reducing the difficulty of rod placement in the traditional method. Alternatively, the screw head and screw rod can be combined first in the traditional method, and then the connecting rod can be passed through the through hole of the screw head with the help of instruments. The overall function is complete and highly practical.

[0053] Unless otherwise specified, in this invention, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the actual orientation or positional relationship shown. They are used only 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. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the embodiments and according to the specific circumstances.

[0054] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention 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 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.

[0055] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A button-type posterior spinal internal fixation system, characterized in that, include: Pedicle screw, one end of which has a ball head; A connecting rod, the top of which has a first protrusion extending along its length; The nail head that connects the pedicle screw and the connecting rod consists of a nail head body, a washer, and a retaining ring. The nail head body has a cavity with its opening facing downwards. The washer is located in the cavity and rotates relative to it. Below the washer is an annular groove formed on the cavity wall. The retaining ring is embedded in the annular groove. The washer has an inner through groove with its opening facing upwards and both ends communicating with the outside. The connecting rod is slidably connected in the inner through groove. The nail head body has a first outer through groove and a second outer through groove, both ends of which communicate with the outside. The connecting rod is also slidably connected in the first outer through groove or the second outer through groove. By rotating the nail head body relative to the washer, the connecting rod can switch positions within the first outer through groove and the second outer through groove. The groove wall of the first outer through groove has a first groove that adapts to the first protrusion. The bottom of the washer has a spherical groove for the ball head to be inserted from bottom to top. The spherical groove communicates with the inner through groove. The side of the washer has a spring piece with a locking hook. The side of the nail head body has a locking groove that allows the locking hook to be inserted when the connecting rod is located in the second outer through groove.

2. The button-type posterior spinal internal fixation system according to claim 1, characterized in that, The retaining ring has an opening and at least one second groove. The second groove has a second protrusion that matches it and is located on the groove wall of the annular groove. A third protrusion located on the washer is inserted into the opening.

3. The button-type posterior spinal internal fixation system according to claim 2, characterized in that, The ball head is provided with ring teeth for the retaining ring to hold it tightly.

4. The button-type posterior spinal internal fixation system according to claim 3, characterized in that, The top of the nail head body has a lever portion for controlling its rotation relative to the washer.

5. The button-type posterior spinal internal fixation system according to claim 4, characterized in that, The lever part is a non-rotating cylindrical shape.

6. The button-type posterior spinal internal fixation system according to claim 5, characterized in that, It also includes a locking device; the locking device has a drive head, on which a lever groove is provided for the lever part to be fitted into.

7. The button-type posterior spinal internal fixation system according to claim 6, characterized in that, The drive head is provided with a guide plate located outside the opening of the lever groove.

Images