Eccentric screw mechanism

Abstract

The present invention discloses an eccentric screw mechanism, which includes a screw, a mounting sleeve, a nail sleeve and a locking member; the screw is a hollow screw and has a central hole arranged through along the axis of the screw. The screw has a shank and a screw head, and the outer peripheral wall of the screw head has a first outer spherical surface area; the inner wall of the mounting sleeve is provided with a first inner spherical surface area, the screw passes through the mounting sleeve, and the first outer spherical surface area and the first inner spherical surface area are in spherical cooperation; the locking member is installed in the mounting sleeve and the screw is locked in the mounting sleeve through the locking member; the nail sleeve is connected to the mounting sleeve and can slide relative to the mounting sleeve along a first direction, and the first direction is perpendicular to the axis of the first inner spherical surface area. By sliding, the inner hole of the nail sleeve and the central hole are aligned or staggered and the staggering distance is controlled. It has the following advantages: ensuring the accuracy of screw placement, guaranteeing the safety of the operation, reducing the irritation to the surrounding soft tissues, significantly shortening the operation time, significantly reducing the blood loss; reducing the occlusion of the surgical field by the internal fixation device during the operation.

Description

Technical Field

[0001] The present invention relates to medical devices, and particularly to an eccentric screw mechanism. Background Art

[0002] At present, the cervical vertebra screws used clinically are solid screws. The solid screw includes a screw head and a screw rod. The end face of the screw head is recessed with an operation groove. Since solid screws are used, there are many problems such as the screw deviating from the screw track during the screw placement process, the screw tail blocking the surgical field of view and the operation space, and hindering the full opening of the cervical vertebra lamina. Summary of the Invention

[0003] The present invention provides an eccentric screw mechanism, which overcomes the deficiencies of the screws in the background art.

[0004] The technical solution adopted by the present invention to solve its technical problems is: an eccentric screw mechanism, including a screw, a mounting sleeve, a nail sleeve and a locking member; the screw is a hollow screw and has a central hole arranged through along the axis of the screw. The screw has a screw rod and a screw head, and the outer peripheral wall of the screw head has a first outer spherical surface area; the inner wall of the mounting sleeve is provided with a first inner spherical surface area, the screw passes through the mounting sleeve, and the first outer spherical surface area and the first inner spherical surface area are in spherical cooperation; the locking member is installed in the mounting sleeve and the screw is locked in the mounting sleeve through the locking member; the nail sleeve is connected to the mounting sleeve and can slide relative to the mounting sleeve along a first direction, and the first direction is perpendicular to the axis of the first inner spherical surface area. By sliding, the alignment or misalignment of the inner hole of the nail sleeve and the central hole and the misalignment distance are controlled.

[0005] In one embodiment: the screw rod has a smooth rod section and a threaded section, and the smooth rod section is fixed between the screw head and the threaded section; the length ratio of the smooth rod section to the threaded section is 1:0.5 - 2.

[0006] In one embodiment: the locking member includes a C-shaped buckle. The inner wall of the C-shaped buckle has a second inner spherical surface area, and the first outer spherical surface area of the screw head is clamped between the first inner spherical surface area and the second inner spherical surface area; a convex structure is provided on the outer wall of the C-shaped buckle, and a groove structure is provided on the inner wall of the mounting sleeve. The convex structure is inserted into the groove structure to achieve locking.

[0007] In one embodiment: a support platform structure is provided on the inner wall of the mounting sleeve, and the C-shaped buckle is adaptively supported on the support platform structure. The support platform structure has a support wall and an inner side wall arranged at an angle with the support wall. The above-mentioned groove structure is provided on the inner side wall. The groove structure includes an annular groove. The above-mentioned convex structure is provided on the outer side wall of the C-shaped buckle. The convex structure includes a flange. The C-shaped buckle is adaptively supported on the support wall, the outer side wall is adaptively in contact with the inner side wall, and the flange is adaptively connected to the annular groove.

[0008] In one embodiment: One end of the first inner spherical surface region axially extends to form a small cylindrical wall, and the other end axially extends to form a large cylindrical wall. The diameter of the first outer spherical surface region is greater than the diameter of the small cylindrical wall and is adapted to the diameter of the large cylindrical wall.

[0009] In one embodiment: The lower end port of the nail sleeve is provided with an enlarged hole. The upper opening periphery of the C-shaped buckle axially extends upward to form an extending portion protruding outside the mounting seat, and the extending portion is connected in the enlarged hole.

[0010] In one embodiment: The upper end face of the nail sleeve is recessed with a through groove penetrating the inner hole of the nail sleeve.

[0011] In one embodiment: The outer peripheral wall of the mounting sleeve has an outer rotating wall and an outer peripheral wall extending upward from the periphery of the outer rotating wall. Plane walls are provided on both sides of the outer peripheral wall, and sliding grooves are recessed in the plane walls. Suspended ears are convexly provided on both sides of the lower end of the nail sleeve, and sliders are provided at the inner extensions of the ends of the suspended ears. The two suspended ears clamp the outer peripheral wall, and the sliders are slidably connected in the sliding grooves.

[0012] Compared with the background art, this technical solution has the following advantages:

[0013] The screw is a hollow screw. The screw head is locked in the mounting sleeve through a locking member. The outer spherical surface region of the screw head and the inner spherical surface region of the mounting sleeve are in spherical cooperation to achieve universal connection. The nail sleeve is connected to the mounting sleeve and can slide relative to the mounting sleeve to control the alignment or misalignment of the inner hole of the nail sleeve and the central hole and the misalignment distance. Therefore, the following technical effects can be achieved: First, during the operation, the guide pin is first placed into the target position according to the surgical requirements. After the position of the guide pin is confirmed to be correct, the hollow screw is accurately placed into the pedicle region along the guide pin, which not only ensures the accuracy of screw placement, guarantees the safety of the operation, but also reduces the irritation to the surrounding soft tissues, significantly shortens the operation time, and significantly reduces the bleeding volume. Second, by sliding the nail sleeve, the occlusion of the internal fixation device on the surgical field during the operation is reduced, which is beneficial to reducing the incidence of operation-related complications and improving the bone healing rate. Third, the screw placement operation is simple, the physical verification has a good reduction effect, the process is controllable, the immediate stability is achieved, and the relative position of the vertebral body is not lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0015] Figure 1 is a three-dimensional schematic diagram of the screw mechanism in the specific embodiment.

[0016] Figure 2 is a front view schematic diagram of the screw mechanism in the specific embodiment.

[0017] Figure 3 is a cross-sectional schematic diagram of the screw mechanism in the specific embodiment.

[0018] Figure 4It is a left view schematic diagram of the screw mechanism of the specific implementation manner.

[0019] Figure 5 It is a top view schematic diagram of the screw mechanism of the specific implementation manner. Specific implementation manner

[0020] Please refer to Figures 1 to 5 , an eccentric screw mechanism applicable to a posterior cervical screw-rod internal fixation system, comprising a screw 1, a mounting sleeve 2, a nail sleeve 3 and a locking member 4.

[0021] The screw 1 is a hollow screw and has a central hole 11 arranged through along the screw axis. The upper end surface of the central hole 11 is reamed to form an operation groove so as to drive the screw to rotate through the operation groove. The screw 1 has a screw rod and a screw head 12. The outer peripheral wall of the screw head 12 has a first outer spherical surface area 121. The screw head is provided with an outer spherical surface area so as to cancel the screw tail. Without the volume occupation of the screw tail, it can increase the surgical operation space and tissue fixation space, and can reduce the possibility of the appearance of blind areas in the intervertebral foramen area. The screw rod has a smooth rod section 13 and a threaded section 14. The smooth rod section 13 is fixed between the screw head 12 and the threaded section 14. The length ratio of the smooth rod section 13 to the threaded section 14 is 1:0.5 - 2, such as 1:1. The smooth rod section 13 is provided to reduce the irritation to the surrounding soft tissues during the screw placement process. The inner wall of the mounting sleeve 2 is provided with a first inner spherical surface area 21. One port of the first inner spherical surface area 21 axially extends to form a small cylindrical wall 22, and the other port axially extends to form a large cylindrical wall 23. The diameter of the first inner spherical surface area 21 is adapted to the diameter of the first outer spherical surface area 121. The diameter of the first outer spherical surface area 121 is larger than the diameter of the small cylindrical wall 22 and is adapted to the diameter of the large cylindrical wall 23. The screw 1 passes through the mounting sleeve 2 and the first outer spherical surface area 121 cooperates with the first inner spherical surface area 21 to form a universal joint.

[0022] The locking piece 4 is installed in the installation sleeve 2 and the screw 1 is locked in the installation sleeve 2 through the locking piece 4. The specific structure is as follows: the locking piece 4 includes a C-shaped buckle 41, the inner wall of the C-shaped buckle 41 has a second inner spherical area 42, the outer wall of the C-shaped buckle 42 is provided with a convex structure 411, and the inner wall of the installation sleeve 2 is provided with a groove structure 24. The C-shaped buckle 42 is installed in the installation sleeve 2 through elastic deformation, and the elastic deformation is reset to make the convex structure 24 inserted into the groove structure 24 to achieve locking, so as to lock the screw 1 in the installation sleeve 2, so that the first outer spherical area 121 of the screw head 12 is clamped between the first inner spherical area 21 and the second inner spherical area 42. The above structure can, firstly, not only achieve locking but also improve the smoothness of the universal connection. Secondly, it is convenient and fast to assemble and disassemble, and the locking is firm, stable and reliable. Furthermore, a support platform structure is provided on the inner wall of the mounting sleeve 2, and the C-shaped buckle 41 is adapted to be supported on the support platform structure. The support platform structure has a support wall 25 and an inner wall 26 arranged at right angles to the support wall. The inner wall 26 is provided with the above-mentioned slot structure 24, and the slot structure includes an annular groove. The outer wall of the C-shaped buckle 41 is provided with the above-mentioned convex structure 411, and the convex structure includes a flange. The C-shaped buckle 41 is adapted to be supported on the support wall 25, and the outer wall is adapted to contact the inner wall 26, and the flange is adapted to connect the annular groove, so that the locking piece can be firmly, stably and reliably locked through the above-mentioned support platform structure to avoid shaking.

[0023] The nail sleeve 3 is mounted on the mounting sleeve 2 and can slide relative to the mounting sleeve 2 along a first direction, the first direction being perpendicular to the axial direction of the first inner spherical area 121, the axial direction of the first inner spherical area 121 being arranged vertically, the first direction being the front-to-back direction, and the alignment or staggering and the staggering distance of the inner hole of the nail sleeve 3 and the center hole 11 being controlled by sliding, and the staggering distance can be limited as needed, such as limiting the maximum staggering distance to plus or minus 3 mm, so it can be flexibly adjusted according to surgical needs, providing sufficient adjustment space for the subsequent installation of connecting rods and fixation of single-door vertebral plates, and can be applicable to a variety of the most commonly used posterior cervical internal fixation procedures in clinical practice, and has the potential to facilitate the installation of connecting rods in revision surgery involving replacement of the nail placement method. In the specific structure: the outer peripheral wall of the mounting sleeve 2 has an outer rotating wall 27 and an outer peripheral wall 28 extending upward from the peripheral edge of the outer rotating wall, the outer rotating wall is like a cone wall, and plane walls are arranged on both sides of the outer peripheral wall and the plane walls are recessed with a slide groove 29; the lower end of the nail sleeve 3 is convexly provided with hanging ears 31 on both sides, and the ends of the hanging ears 31 extend inwardly to provide a slider 32, the two hanging ears 31 clamp the outer peripheral wall and the slider 32 is slidably connected in the slide groove 29, and the use of this structure facilitates assembly and improves the sliding guidance; the lower end of the nail sleeve 3 is provided with an expanded hole 32, and the opening peripheral edge of the C-shaped buckle 42 extends upward to form a protruding portion 43 protruding out of the mounting seat, and the protruding portion 43 is connected to the expanded hole 31. The use of this structure can further improve the sliding guidance; the upper end surface of the nail sleeve 3 is recessed with a through groove 33 that penetrates the inner hole of the nail sleeve so that the connecting rod can be connected.

[0024] The above-mentioned screw 1, mounting sleeve 2, nail sleeve 3 and locking member 4 are made of titanium alloy material.

[0025] As mentioned above, it is only a preferred embodiment of the present invention, so the scope of implementation of the present invention cannot be limited accordingly. That is, equivalent changes and modifications made according to the scope of the present invention patent and the content of the specification should still fall within the scope covered by the present invention.

Claims

1. Eccentric screw mechanism, including a screw, characterized in that: It further includes an installation sleeve, a nail sleeve and a locking member; the screw is a hollow screw and has a central hole arranged through along the screw axis. The screw has a shank and a screw head, and the outer peripheral wall of the screw head has a first outer spherical surface area; the inner wall of the installation sleeve is provided with a first inner spherical surface area, the screw passes through the installation sleeve, and the first outer spherical surface area and the first inner spherical surface area are in spherical fit; the locking member is installed in the installation sleeve and the screw is locked in the installation sleeve through the locking member; the nail sleeve is connected to the installation sleeve and can slide relative to the installation sleeve in a first direction, the first direction is perpendicular to the axis of the first inner spherical surface area, and the alignment or misalignment and the misalignment distance between the inner hole of the nail sleeve and the central hole are controlled by sliding; the locking member includes a C-shaped buckle, the inner wall of the C-shaped buckle has a second inner spherical surface area, and the first outer spherical surface area of the screw head is clamped between the first inner spherical surface area and the second inner spherical surface area; a convex structure is provided on the outer wall of the C-shaped buckle, and a card slot structure is provided on the inner wall of the installation sleeve, and the convex structure is inserted into the card slot structure to achieve locking; a support platform structure is provided on the inner wall of the installation sleeve, the C-shaped buckle is adaptively supported on the support platform structure, the support platform structure has a support wall and an inner side wall arranged at an angle to the support wall, and the above-mentioned card slot structure is provided on the inner side wall. The card slot structure includes an annular groove, the above-mentioned convex structure is provided on the outer side wall of the C-shaped buckle, the convex structure includes a flange, the C-shaped buckle is adaptively supported on the support wall, the outer side wall is adaptively in contact with the inner side wall, and the flange is adaptively connected to the annular groove; the outer peripheral wall of the installation sleeve has an outer rotating wall and an outer peripheral wall extending upward from the periphery of the outer rotating wall, and flat walls are provided on both sides of the outer peripheral wall and sliding grooves are recessed in the flat walls; the lower ends of both sides of the nail sleeve are convexly provided with hanging ears, the ends of the hanging ears extend inward to form sliders, and the two hanging ears on both sides are clamped on the outer peripheral wall and the sliders are slidably connected in the sliding grooves.

2. The eccentric screw mechanism according to claim 1, wherein: The shank has a smooth rod section and a threaded section, and the smooth rod section is fixed between the screw head and the threaded section; the length ratio of the smooth rod section to the threaded section is 1:0.5 - 2.

3. The eccentric screw mechanism according to claim 1, characterized in that: One port of the first inner spherical surface area axially extends into a small cylindrical wall, and the other port axially extends into a large cylindrical wall. The diameter of the first outer spherical surface area is larger than the diameter of the small cylindrical wall and equal to the diameter of the large cylindrical wall.

4. The eccentric screw mechanism according to claim 1, wherein: The lower port of the nail sleeve is provided with an enlarged hole, and the peripheral edge of the upper opening of the C-shaped buckle axially extends into an extending part protruding out of the mounting seat, and the extending part is connected in the enlarged hole.

5. The eccentric screw mechanism according to claim 1 or 2, characterized in that: A through groove penetrating the inner hole of the nail sleeve is recessed on the upper end surface of the nail sleeve.

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