A snap-on low-profile pedicle screw

Abstract

The present application relates to the field of medical devices, and relates to a buckle type low-cut pedicle screw, which comprises a lock cap, a connecting rod, a check ring, a screw rod and a base, the base is connected to the screw rod in a universal manner, an inner socket one is arranged in the base, the check ring is clamped in the base and located on the upper end of the screw rod, an inner socket two coaxial with the socket one is arranged in the check ring, an annular clamping groove is arranged on the outer side of the base below the socket one, the lock cap is arranged on the outer side of the base, an insertion block clamped in the annular clamping groove is arranged on the lower end of the lock cap, an insertion hole three is arranged on the side end of the lock cap, the insertion hole three is in communication with the insertion hole two, the connecting rod is arranged through the insertion hole one, the insertion hole two and the insertion hole three and located on the upper end of the screw rod, the lock cap and the base are locked in one step in a buckle form to lock the connecting rod, the traditional thread screw plug and the nail cap are prevented from being wrong in thread and cutting thread, and the clinical problems are avoided, the locking efficiency is high, and the operation time is reduced.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and specifically to a snap-fit ​​low-notch pedicle screw. Background Technology

[0002] Posterior spinal pedicle screw systems are currently the most widely used internal fixation systems in spinal surgery, accounting for over 70% of spinal surgeries in China. Pedicle screws of various diameters and lengths are widely used in posterior spinal procedures. The most common complete pedicle screw system is the rod-screw system, which consists of a screw, nut, and clamping block. The nut is a device that locks the rod to the screw head from bottom to top after the screw head is inserted. Currently, threaded locking is the more traditional mainstream product, and surgeons are accustomed to using this type of product because it provides good instrument feedback during tightening. However, the disadvantages are: 1. During the locking process, the threads may become misaligned or stripped. Tightening the nut multiple times is time-consuming, and the tightness of the nut is not easy to control accurately. Stripping often occurs, damaging the nut or nail head threads. Even with torque limit wrenches provided by most manufacturers, this situation cannot be completely prevented. 2. Because space needs to be reserved at the top of the nail body to accommodate the nut, the notch of the pedicle screw is relatively high. The notch refers to the distance from the top of the screw to the top of the nut, excluding the screw rod. A large distance may cause soft tissue irritation, irritate or compress tendons, ligaments and other tissues, leading to infection, etc.

[0003] In summary, to address the shortcomings of existing technologies, it is necessary to design a snap-fit ​​low-notch pedicle screw that is simple in structure, easy to install, and prevents misalignment or slippage. Summary of the Invention

[0004] To address the problems of the prior art, this invention provides a snap-fit ​​low-notch pedicle screw.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A snap-fit ​​low-notch pedicle screw includes: a locking cap, a connecting rod, a retaining ring, a screw rod, and a base. The base is rotatably connected to the screw rod. The base has a vertical channel I inside and a socket I perpendicular to the vertical channel I on the base. The retaining ring is snapped into the vertical channel I and located at the upper end of the screw rod. The retaining ring has a socket II coaxial with the socket I. The socket I and socket II are identical in shape to the connecting rod. The openings of the socket I and socket II are upward-opening. The outer side of the base has an annular groove located below the socket I. The locking cap is located on the outer side of the base. The locking cap has a vertical channel II inside and a plug at the lower end of the locking cap that snaps into the annular groove. The side end of the locking cap has a socket III communicating with the vertical channel II and communicating with a socket II. The opening of the socket III is downward-opening. The connecting rod passes through the socket I, socket II, and socket III and is located at the upper end of the screw rod.

[0007] In a further improvement, a limiting block is provided on the inner top surface of the lock cap. The limiting block is located inside the second vertical channel and positioned directly above the retaining ring. The limiting block includes two sets of symmetrically arranged arc-shaped pressure blocks coaxial with the second insertion port. The limiting block cooperates with the retaining ring to clamp the connecting rod.

[0008] In a further improvement, the upper end of the annular groove of the base is provided with a limiting frustum, the outer radial direction of the limiting frustum is reduced upward, the inner side of the lock cap is provided with a limiting groove that engages with the limiting frustum, and the insert blocks are symmetrically arranged in four sets.

[0009] In a further improvement, the first and second sockets are circular openings, the upper end of the third socket is a circular opening, and the lower end of the third socket is a rectangular opening.

[0010] In a further improvement, the upper end of the retaining ring is symmetrically provided with locking blocks, and the upper end of the base is symmetrically provided with locking grooves that match and engage with the locking blocks.

[0011] In a further improvement, the upper end of the screw rod is provided with a ball socket, and the base is provided with a ball socket groove, wherein the ball socket is rotatably disposed within the ball socket groove.

[0012] In a further improvement, the top of the screw rod is provided with a stepped portion, and the bottom of the retaining ring is provided with a tapered hole whose inner radial direction decreases upward.

[0013] In a further improvement, the base is provided with symmetrical through grooves, the upper end of which is connected to the socket, and the side end of the lock cap is provided with two sets of through grooves that are connected to the vertical channel.

[0014] In a further improvement, the top of the lock cap is provided with a guide wire hole that communicates with the vertical channel 2, and the top of the retaining ring is provided with a gap hole between it and the slot.

[0015] Compared with the prior art, the advantages of the snap-fit ​​low-notch pedicle screw of the present invention are as follows:

[0016] This pedicle screw uses a non-threaded locking structure. The locking cap and base are locked together in one step using a snap-fit ​​mechanism, avoiding clinical problems such as misalignment and wire cutting that can occur with traditional threaded screws. It also offers high locking efficiency, reducing surgical time. A sound indicates successful fixation when the locking cap's insert engages with the annular groove in the base, providing excellent feedback. Compared to traditional pedicle screws, the notch is reduced by approximately 3.5mm, minimizing tissue irritation. The locking cap's third insertion port, the retaining ring's second insertion port, and the base's first insertion port increase the contact area with the connecting rod, enhancing the locking strength. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of the exploded view of the present invention.

[0019] Figure 3 This is a schematic diagram of the internal structure of the present invention.

[0020] Figure 4 This is a schematic diagram of the structure of the lock cap in this invention.

[0021] Figure 5 This is a schematic diagram of the retaining ring in the present invention.

[0022] Figure 6 This is a schematic diagram of the base structure in this invention.

[0023] Figure 7 This is a structural diagram comparing the present invention with existing technologies.

[0024] In the diagram, 1-lock cap, 11-insertion block, 12-insertion port three, 13-vertical channel two, 14-limiting block, 141-arc-shaped pressure block, 15-limiting slot, 2-connecting rod, 3-retaining ring, 31-insertion port two, 32-slot block, 33-spacer hole, 34-conical hole, 4-screw rod, 41-ball socket, 42-stepped part, 5-base, 51-vertical channel one, 52-insertion port one, 53-annular slot, 54-limiting frustum, 55-slot, 56-ball socket groove, 61-through groove one, 62-through groove two, 7-guide wire hole. Detailed Implementation

[0025] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are 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, they should not be construed as limitations on this invention.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] The following describes the embodiments and appendices. Figures 1-7 The technical solution of the present invention will be further described below.

[0028] Example 1

[0029] A snap-fit ​​type low-notch pedicle screw includes: a locking cap 1, a connecting rod 2, a retaining ring 3, a screw rod 4, and a base 5. The base 5 is rotatably connected to the screw rod 4. The base 5 has a vertical channel 51 inside and a socket 52 perpendicular to the vertical channel 51 on the base 5. The retaining ring 3 is snapped into the vertical channel 51 and located at the upper end of the screw rod 4. The retaining ring 3 has a second socket 31 coaxial with the first socket 52. The first socket 52 and the second socket 31 are identical in shape to the connecting rod 2. The openings of the first socket 52 and the second socket 31 are upward-facing. The outer side of the base 5 has a socket located below the first socket 52. The lock cap 1 is located on the outside of the base 5, and the lock cap 1 has a vertical channel 2 13 inside. The lower end of the lock cap 1 has a plug block 11 that is engaged with the annular slot 53. The side end of the lock cap 1 has a plug port 3 12 that communicates with the vertical channel 2 13. The plug port 3 12 is connected to the plug hole 2 31 and the plug port 3 12 is open downward. The connecting rod 2 passes through the plug port 1 52, the plug port 2 31 and the plug port 3 12 and the connecting rod 2 is located at the upper end of the screw rod 4. The plug port 1 52 and the plug port 2 31 are circular openings. The upper end of the plug port 3 12 is a circular opening and the lower end of the plug port 3 12 is a rectangular opening.

[0030] The locking cap 1 and the connecting rod are made of molybdenum-rhenium alloy, which significantly increases the mechanical stability of the system while reducing the notch depth compared to traditional titanium alloy. The connecting rod 2 functions similarly to the orthopedic rod in a traditional pedicle screw system.

[0031] like Figures 1 to 7As shown, the working principle of this invention is as follows: The retaining ring 3 is pre-installed on the upper end of the screw rod 4. The base 5 is pressed into the upper end of the screw rod 4 and can rotate in all directions. The base 5 is snapped into the retaining ring 3 inside. Then, the connecting rod 2 is pressed down from the vertical channel 13 of the base 5 into the insertion port 52 of the base 5 and the insertion port 31 of the retaining ring 3. Then, the locking cap 1 is put on the outside of the base 5. The insertion port 12 on the locking cap 1 is inserted into the connecting rod 2. The insertion block 11 on the locking cap 1 is snapped into the annular groove 53 inside the base 5 during the downward process, realizing the snap-fit ​​connection between the locking cap 1 and the base 5. When the locking cap 1 and the base 4 are snapped together, the connecting rod 2 is squeezed to deform it, thereby pressing and locking the connecting rod 2.

[0032] Before the lock cap 1 is snapped into the base 5, the base 5 is omnidirectionally connected to the screw rod 4 and there is a gap between the retaining ring and the screw rod 4. This allows the connecting rod 2 to be omnidirectionally adjusted on the screw rod 4 via the base 5. After being adjusted to the appropriate position, the lock cap 1 and the base 4 snap together and press the connecting rod 2. The connecting rod 2 presses down and pushes the retaining ring 3, causing the retaining ring 3 to lock the lower end of the screw rod 4, thus achieving position locking.

[0033] This pedicle screw uses a non-threaded locking structure. The locking cap and the base are locked in one step by snapping together, which avoids clinical problems such as misalignment and cutting of threads in traditional threaded plugs and screw caps. At the same time, the locking efficiency is high, which reduces the operation time. When the insert of the locking cap is inserted into the annular groove of the base and a sound is produced, it can be known that the fixation is completed, which has a good feedback.

[0034] like Figure 7 As shown, traditional plug-type spinal screws require the plug to be screwed into the threaded hole inside the screw head to clamp the orthotic rod. To ensure the effectiveness of the plug clamping the orthotic rod, the threaded hole inside the screw head has a certain depth. Therefore, the height H1 of the traditional screw head is higher than the height H2 in this pedicle screw. H3 is the difference in notch height between H1 and H2. Compared with the traditional pedicle screw, the notch can be reduced by about 3.5mm, reducing tissue irritation.

[0035] By using the third socket of the locking cap, the second socket of the retaining ring, and the first socket of the base, the contact area with the connecting rod is increased, thereby improving the locking strength of the connecting rod.

[0036] As a further embodiment, the inner top surface of the lock cap 1 is provided with a limiting block 14. The limiting block 14 is located in the vertical channel 2 13 and is positioned directly above the retaining ring 3. The limiting block 14 includes two sets of symmetrically arranged arc-shaped pressing blocks 141 coaxial with the insertion port 2 31. The limiting block 14 cooperates with the retaining ring 3 to clamp the connecting rod 2.

[0037] like Figure 3 and Figure 4As shown, when the lock cap 1 engages with the base 5, the two sets of arc-shaped pressure blocks 141 inside the lock cap 1 move down and further compress the connecting rod 2. The arc-shaped pressure blocks 141, together with the retaining ring 3 at the lower end, simultaneously compress and lock the connecting rod 2, further clamping the connecting rod 2 and improving the mechanical stability of the entire system.

[0038] As a further embodiment, the annular groove 53 of the base 5 is provided with a limiting frustum 54 at its upper end. The limiting frustum 54 is set to decrease in size radially upwards. The inner side of the lock cap 1 is provided with a limiting groove 15 that engages with the limiting frustum 54. The insert blocks 11 are symmetrically arranged in four sets at intervals. Figure 3 and Figure 4 As shown, during the pressing process, the limiting groove 15 slides into the limiting frustum 54, which is gradually increased in size along the outer radial direction. The lower end of the locking cap 1 expands elastically until the four sets of inserts 11 are inserted into the annular groove 53 and then elastically close. The limiting frustum 54, which is increased in size along the outer radial direction, can prevent the inserts 11 from dislodging from the annular groove 53, thus improving the stability of the locking.

[0039] As a further embodiment, the upper end of the retaining ring 3 is symmetrically provided with locking blocks 32, and the upper end of the base 5 is symmetrically provided with locking grooves 55 that match and engage with the locking blocks 32. Figure 3 As shown, the retaining ring 3 is snapped into the slot 55 on the base 5 by two sets of locking blocks 32. The snap-fit ​​connection facilitates the fixing between the retaining ring and the base.

[0040] As a further embodiment, the upper end of the screw rod 4 is provided with a ball socket 41, and the base 5 is provided with a ball socket groove 56 inside, with the ball socket 41 rotatably disposed within the ball socket groove 56. Figure 3 As shown, the ball joint between the screw rod 4 and the base 5 ensures that the base 5 can rotate omnidirectionally relative to the screw rod 4 while restricting its vertical movement in the radial direction, thereby preventing the connecting rod from loosening vertically and ensuring the fixation stability of the spinal screw.

[0041] As a further embodiment, the top of the screw rod 4 is provided with a stepped portion 42, and the bottom of the retaining ring 3 is provided with a tapered hole 34 whose inner radial direction decreases upward. Figure 3 and Figure 5 As shown, when the retaining ring 3 is pressed down by the connecting rod 2, the stepped portion 42 on the screw rod 4 can increase the friction between the retaining ring 3 and the tapered hole 34, further improving the locking force and further preventing the connecting rod from rotating relative to the screw rod.

[0042] As a further embodiment, the base 5 is symmetrically provided with through grooves 61, the upper end of which is connected to the socket 52, and the side end of the lock cap 1 is provided with two sets of through grooves 62 that are connected to the vertical channel 13. Figure 4 and Figure 6As shown, the through groove 61 on the base 5 increases the elastic deformation performance of the base 5, making it easier for the connecting rod 2 to be snapped into its socket 52. The through groove 62 on the lock cap 1 also increases the elastic deformation performance of the lock cap 1, making it easier for the connecting rod 2 to be snapped into its socket 12.

[0043] As a further embodiment, the top of the lock cap 1 is provided with a guide wire hole 7 communicating with the vertical channel 2 13, and the top of the retaining ring 3 is provided with a spacer hole 33 between it and the slot 55. Figure 3 As shown, when a hollow screw is used, the guide wire is inserted into the guide wire hole 7 and then out through the spacer hole 33, so that the screw can reach the designated position along the pre-positioned guide wire. The guide wire plays a guiding role in the operation.

[0044] 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 snap-fit ​​type low-notch pedicle screw, characterized in that, include: The system comprises a lock cap, a connecting rod, a retaining ring, a screw rod, and a base. The base is rotatably connected to the screw rod. The base has a vertical channel I inside and a socket I perpendicular to the vertical channel I on the base. The retaining ring is engaged inside the vertical channel I and located at the upper end of the screw rod. The retaining ring has a socket II coaxial with the socket I. Socket I and socket II are identical in shape to the connecting rod. The openings of socket I and socket II are upward-facing. The outer side of the base has an annular groove below socket I. The lock cap is located on the outer side of the base. The lock cap has a vertical channel II inside and a plug at the lower end of the lock cap that engages with the annular groove. The side end of the lock cap has a socket III communicating with the vertical channel II and is connected to a socket II. The opening of socket III is downward-facing. The connecting rod passes through socket I, socket II, and socket III and is located at the upper end of the screw rod. The inner top surface of the lock cap is provided with a limiting block. The limiting block is located inside the second vertical channel and is positioned directly above the retaining ring. The limiting block includes two sets of symmetrically arranged arc-shaped pressing blocks coaxial with the second insertion port. The limiting block cooperates with the retaining ring to clamp the connecting rod. The base has a limiting frustum at the upper end of the annular slot. The limiting frustum is set to decrease in size radially upward. The inner side of the lock cap has a limiting slot that engages with the limiting frustum. The insert blocks are symmetrically arranged in four sets at intervals. The first and second sockets are circular openings, the upper end of the third socket is a circular opening, and the lower end of the third socket is a rectangular opening; The top of the screw rod is provided with a stepped portion, and the bottom of the retaining ring is provided with a tapered hole that decreases in the inner radial direction upwards; The upper end of the screw rod is provided with a ball socket, and the base is provided with a ball socket groove inside, with the ball socket being rotatably disposed in the ball socket groove.

2. The snap-fit ​​type low-notch pedicle screw according to claim 1, characterized in that, The upper end of the retaining ring is symmetrically provided with locking blocks, and the upper end of the base is symmetrically provided with locking grooves that match and engage with the locking blocks.

3. The snap-fit ​​low-notch pedicle screw according to claim 1, characterized in that, The base is symmetrically provided with a through groove 1, the upper end of which is connected to the socket 1, and the side end of the lock cap is provided with two sets of through grooves 2 that are connected to the vertical channel 2.

4. A snap-fit ​​low-notch pedicle screw according to claim 1, characterized in that, The top of the lock cap is provided with a guide wire hole that communicates with the vertical channel 2, and the top of the retaining ring is provided with a gap hole between it and the slot.

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