A lumbar facet joint function replacement fixation device

Abstract

The present invention provides a lumbar facet joint function replacement fixation device, a lumbar facet joint function replacement fixation device, comprising four pedicle screws, four pedicle auxiliary screws, four double-frame fixing screws, a pair of mirror-symmetrical scoliosis fixation frames, an upper connecting rod, a pair of scoliosis joints, an axial rotation neck, a buffer fixing sleeve and a lower connecting rod; the upper connecting rod and the lower connecting rod are arranged in parallel, and both ends of them are provided with through holes; the pedicle screws are fixed to the upper connecting rod or the lower connecting rod through the corresponding through holes through the pedicle auxiliary screws; the upper half of the scoliosis fixation frame is a fixing rod with an opening on the side wall, and the lower half is a circular ring with an opening on the bottom. Compared with the fixation instruments used in traditional posterior lumbar decompression and fusion fixation, the present invention can retain the physiological movements of six directions of moderate spinal flexion and extension, scoliosis and rotation, and avoid the accelerated degeneration of adjacent segments due to the loss of mobility of the diseased segment and abnormal changes in spinal biomechanics.

Description

Technical Field

[0001] The present invention relates to the technical field of orthopedic spinal surgery implants, and in particular to a lumbar facet joint function replacement fixation device. Background Art

[0002] Lumbar degenerative diseases include intervertebral disc degeneration, lumbar spinal stenosis and spondylolisthesis. Patients with lumbar degenerative diseases often experience lower back pain, lower limb pain and lower limb weakness, which greatly reduces the quality of life of patients. Among diseases such as lumbar disc herniation and lumbar spinal stenosis, posterior lumbar laminectomy is the most commonly used decompression procedure for treatment, such as Figure 2 As shown in the figure, the facet joints on both sides of the responsible gap are destroyed during surgery, so instrumented fusion fixation is often required to maintain stability. In addition, fusion is also necessary for unstable diseases such as spondylolisthesis. Therefore, instrumented fusion is currently widely used to address spinal instability in lumbar degenerative spinal disease. However, complications of spinal fusion are degeneration of adjacent segments secondary to biomechanical changes, which may lead to symptom recurrence and worsening, and even forced reoperation. Summary of the Invention

[0003] In response to the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a lumbar facet joint function replacement fixation device to replace the functions of the intervertebral disc and facet joint after extensive decompression, while maintaining the horizontal stability of the corresponding spinal segment and retaining a certain degree of mobility.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A lumbar facet joint functional replacement fixation device comprises four identical pedicle screws, four identical pedicle auxiliary screws, four identical double-frame fixation screws, a pair of mirror-symmetrical scoliosis fixation frames, an upper connecting rod, a pair of scoliosis joints, an axial rotation neck, a buffer fixation sleeve and a lower connecting rod;

[0006] The upper connecting rod and the lower connecting rod are arranged parallel to each other, and both ends of them are provided with through holes, and the axes of the four through holes are parallel and perpendicular to the upper connecting rod; the pedicle screws are fixed to the upper connecting rod or the lower connecting rod by passing the pedicle auxiliary screws through the corresponding through holes;

[0007] The upper half of the side bending fixing frame is a fixing rod with an opening on the side wall, and the lower half is a circular ring with an opening at the bottom, and screw holes are respectively provided at the upper end of the fixing rod, the upper end of the circular ring, and the left and right sides of the middle of the circular ring, which screw holes match the double-frame fixing screws; the inner wall edge of the circular ring with an opening at the bottom is provided with a convex ridge along the circumferential direction; the two side bending fixing frames are relatively superimposed and installed at the midpoint of the upper connecting rod, and the openings on the fixing rods of the two side bending fixing frames are relatively formed to form a circular ring sleeve outside the connecting rod, and the screw holes at their corresponding positions are connected, and are respectively fixed by four double-frame fixing screws; at the same time, arc grooves are provided on the inner walls of the openings of the fixing rods of the two side bending fixing frames, and protrusions are respectively provided on both sides of the upper connecting rod, and the two protrusions can slide in the corresponding arc grooves respectively, so that the fixing frame formed by the two side bending fixing frames can rotate around the upper connecting rod within a certain arc range;

[0008] The side bending joint includes a left half and a right half, each of which is a half-cylinder with a flat bottom end, and the left half and the right half are correspondingly buckled together through a plurality of insertion rods and holes provided on opposite side walls to form a cylindrical body with a flat bottom end; grooves are respectively provided on the edges of the arc surface of the cylinder along the circumferential direction, and the two grooves correspond to the positions and shapes of the two ridges on the inner wall of the circular ring of the lower half of the side bending fixing frame, and the ridges can slide relatively along the grooves in which they are located;

[0009] The axial rotating neck is a stepped cylinder with a larger upper portion and a smaller lower portion. The side walls where the left and right halves of the lateral bending joint contact with each other are respectively provided with grooves that match the shape of the upper half of the axial rotating neck. The upper half of the axial rotating neck is installed in the groove and can rotate around its own axis relative to the groove. The lower end of the axial rotating neck extends out of the lateral bending joint.

[0010] The buffer fixed sleeve includes a connected sleeve upper part and a sleeve lower part. The upper part of the sleeve is a cylinder with an open upper end and a closed lower end. The lower end of the axial rotating neck is inserted into the upper part of the sleeve and can move up and down; the lower part of the sleeve is a forked structure composed of two support columns, and lower connecting rod sleeves are respectively provided at both ends of the forked structure. The lower connecting rod sleeves are respectively sleeved on the lower connecting rod to achieve fixation. The two support columns and the lower connecting rod form a triangle.

[0011] Furthermore, a U-shaped opening is provided on the non-threaded end of the pedicle screw, and a threaded hole matching the pedicle auxiliary screw is provided at the bottom of the U-shaped opening. The U-shaped opening is used to insert the upper connecting rod or the lower connecting rod into it, and the pedicle auxiliary screw passes through the screw hole of the upper connecting rod or the lower connecting rod into the threaded hole, thereby fixing the upper connecting rod or the lower connecting rod to the corresponding pedicle screw.

[0012] Furthermore, four convex strips with a length of three-quarters of the lower connecting rod are evenly arranged along the circumference in the middle of the side wall of the lower connecting rod, and the length direction of the convex strips is consistent with the length direction of the lower connecting rod; the convex strips correspond one-to-one with multiple grooves arranged on the inner wall of the lower support column of the sleeve.

[0013] Furthermore, it also includes a buffer ball, and the lower end of the axial rotating neck is separated from the buffer fixing sleeve by the buffer ball.

[0014] Furthermore, two ridges are symmetrically provided on the side wall of the lower end of the axial rotating neck, and two tracks matching the ridges are symmetrically provided on the upper inner wall of the sleeve. The ridges can slide up and down along the tracks to realize the up and down sliding of the axial rotating neck 7 relative to the buffer fixed sleeve.

[0015] Furthermore, the double-frame fixing screws, lateral bending fixing frame, connecting rod, lateral bending joint, axial rotation neck and buffer fixing sleeve are made of titanium alloy, PEEK carbon or titanium alloy.

[0016] Furthermore, the buffer ball is made of polycarbonate polyurethane PCU material, polyurethane PU, silicone, rubber, or hydrogel.

[0017] Furthermore, the pedicle screws are spinal expandable fixation screws.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0019] (1) Compared with the fixation devices used in traditional posterior lumbar decompression and fusion fixation, the present invention can retain the physiological movement of the six directions of spinal flexion and extension, scoliosis and rotation, and avoid the accelerated degeneration of adjacent segments due to the loss of mobility of the diseased segment and abnormal changes in spinal biomechanics. While functionally replacing the facet joints, it provides immediate alignment and stabilization of the spinal segments at the level of a single spine. Specifically, there is an arc-shaped groove in the side wall of the upper fixing rod of the scoliosis fixation device, which cooperates with a pair of protrusions in the middle of the upper connecting rod to maintain the fixation effect while ensuring moderate forward flexion and backward extension activities with the help of the rotation of the upper connecting rod itself; the ridges on the side wall of the lower circular ring of the scoliosis fixation device are the same shape as the outer contour of the scoliosis joint and match each other, and the lower end opening has a certain angle, which can realize the left and right scoliosis of the spine within the physiological range; in addition, the scoliosis joint contains a groove that completely matches the outer contour of the axial rotation neck, which can realize the physiological function of rotation along the axis of the body.

[0020] (2) After laminectomy and facet joint resection, the fixation device of the present invention can be used as a posterior accessory to support and protect the contents of the spinal canal; the buffer balls therein can replace the shock-absorbing effect of the facet joint and reduce the load borne by the intervertebral disc.

[0021] (3) The bump design of the upper connecting rod and the angle limit of the lower opening of the scoliosis fixation frame can ensure flexion and extension and scoliosis while limiting excessive movement, thus avoiding fixation failure and secondary injury caused by excessive movement.

[0022] (4) The device of the present invention is easy to use, and its implantation operation is similar to posterior lumbar laminectomy, decompression and fusion surgery, without the need for an additional surgical approach. At the same time, it adopts a pedicle screw assembly (i.e., pedicle screw, pedicle auxiliary screw) that has been used clinically for many years. In addition, the various parts of the device can be integrated as an integrated accessory, which is easy to use and can meet a wide range of clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the normal lumbar vertebra structure of the human body, where (a) is the normal lumbar vertebra structure of the human body from the back, and (b) is the side view of (a).

[0024] Figure 2 This is a schematic diagram of the resection part of posterior decompression laminectomy, where the dotted part is the resection part.

[0025] Figure 3 It is a schematic diagram of each component in the present invention.

[0026] Figure 4 It is a structural schematic diagram of the lumbar facet joint function replacement fixation device of the present invention.

[0027] Figure 5 This is a schematic diagram of drilling a hole in the lumbar vertebra before implanting the lumbar facet joint function replacement fixation device of the present invention into the lumbar vertebra.

[0028] Figure 6 Schematic diagram of a scoliosis fixation frame, wherein (a) and (b) are a pair of mirror-symmetrical scoliosis fixation frames.

[0029] Figure 7 Schematic diagram of the lateral bending joint, axial rotation neck and buffer ball.

[0030] Figure 8 Schematic diagram of a buffer fixing sleeve, wherein (a) is a front view, (b) is a side view, (c) is a bottom view, and (d) is a top view.

[0031] Figure 9 Schematic diagram of a side bending joint, an axial rotating neck, a buffer ball and a buffer fixing sleeve, wherein (a) is an assembly diagram and (b) is a vertical cross-sectional view of (a).

[0032] Figure 10 It is a structural schematic diagram of the upper connecting rod and the lower connecting rod.

[0033] The present invention is further explained below with reference to the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] like Figure 3 、 Figure 4 As shown, the lumbar facet joint functional replacement fixation device provided in this embodiment includes four identical pedicle screws (1-1, 1-2, 1-3, 1-4), four identical pedicle auxiliary screws (2-1, 2-2, 2-3, 2-4), four identical double-frame fixation screws (3-1, 3-2, 3-3, 3-4), a pair of mirror-symmetrical scoliosis fixation frames (4-1, 4-2), an upper connecting rod (5), a pair of scoliosis joints (6-1, 6-2), an axial rotation neck (7), a buffer ball (8), a buffer fixation sleeve (9) and a lower connecting rod (10).

[0036] The upper connecting rod (5) and the lower connecting rod (10) are arranged parallel to each other, and both ends of the upper connecting rod (5) are provided with through holes, and the axes of the four through holes are parallel and perpendicular to the upper connecting rod (5); a U-shaped opening is provided on the non-threaded end of the pedicle screw, and a threaded hole matching the pedicle auxiliary screw is opened at the bottom of the U-shaped opening, and the U-shaped opening is used to clamp the upper connecting rod (5) or the lower connecting rod (10) therein, and the pedicle auxiliary screw passes through the screw hole of the upper connecting rod (5) or the lower connecting rod (10) and enters the threaded hole, thereby fixing the upper connecting rod (5) or the lower connecting rod (10) to the corresponding pedicle screw.

[0037] like Figure 6As shown, the upper half of the lateral bending fixing frame (4-1) is a fixing rod with an opening on the side wall, and the lower half is a circular ring with an opening on the bottom. Screw holes are respectively provided at the upper end of the fixing rod, the upper end of the circular ring, and the left and right sides of the middle of the circular ring, and the screw holes match the double-frame fixing screws; the inner wall edge of the circular ring with an opening at the bottom is provided with a ridge along the circumferential direction; the lateral bending fixing frame (4-2) and the lateral bending fixing frame (4-1) are mirror-symmetrical in structure; the two lateral bending fixing frames (4-1, 4-2) are relatively superimposed and installed at the midpoint of the upper connecting rod (5), and the openings on the fixing rods of the two are relatively formed to form a circular ring sleeved outside the connecting rod (5), and the screw holes at their corresponding positions are connected, and are respectively fixed by passing through four double-frame fixing screws (3-1, 3-2, 3-3, 3-4). At the same time, arc-shaped grooves are provided on the inner walls of the openings of the fixing rods of the two side bending fixing frames (4-1, 4-2), and protrusions are provided on both sides of the upper connecting rod (5). The two protrusions can slide in the corresponding arc-shaped grooves, so that the fixing frame formed by the two side bending fixing frames (4-1, 4-2) can rotate around the upper connecting rod (5) within a certain arc range.

[0038] like Figures 7-9 As shown, the side bending joint (6) includes a left half (6-1) and a right half (6-2), and the left half (6-1) and the right half (6-2) are both half cylinders with flat bottoms, and the left half (6-1) and the right half (6-2) are correspondingly buckled together through a plurality of insertion rods and holes provided on opposite side walls to form a cylinder with a flat bottom; grooves are respectively provided on the edges of the arc surface of the cylinder along the circumferential direction, and the two grooves correspond in position and shape to the two ridges on the inner wall of the circular ring of the lower half of the side bending fixing frame (4-1), and the ridges can slide relatively along the grooves in which they are located.

[0039] The axial rotating neck (7) is a stepped cylinder with a larger upper portion and a smaller lower portion. The side walls of the left half (6-1) and the right half (6-2) of the lateral bending joint (6) that contact each other are respectively provided with grooves matching the shape of the upper half of the axial rotating neck (7). The upper half of the axial rotating neck (7) is installed in the groove and can rotate around its own axis relative to the groove. The lower end of the axial rotating neck (7) extends out of the lateral bending joint (6).

[0040] The buffer fixing sleeve (9) comprises a sleeve upper part (9-1) and a sleeve lower part (9-2) connected to each other. The sleeve upper part (9-1) is a cylindrical body with an open upper end and a closed lower end. The lower end of the axial rotating neck (7) is inserted into the sleeve upper part (9-1) and can move up and down. The sleeve lower part (9-2) is a bifurcated structure composed of two support columns, and lower connecting rod sleeves are respectively provided at both ends of the bifurcated structure. The lower connecting rod sleeves are respectively sleeved on the lower connecting rod (10) to achieve fixation. The two support columns and the lower connecting rod (10) form a triangle.

[0041] Four convex strips with a length of three-quarters of the lower connecting rod are evenly arranged along the circumference in the middle of the side wall of the lower connecting rod (10), and the length direction of the convex strips is consistent with the length direction of the lower connecting rod (10); the convex strips are matched one by one with multiple grooves arranged on the inner wall of the support column of the lower part (9-2) of the sleeve to prevent the upper connecting rod 5 and the lower connecting rod 10 from slipping in the sagittal direction.

[0042] Preferably, the lower end of the axial rotating neck (7) and the buffer fixing sleeve (9) are separated by a buffering ball (8), thereby achieving stress buffering between the upper and lower parts.

[0043] Preferably, two ridges are symmetrically provided on the side wall of the lower end of the axial rotating neck (7), and two tracks matching the ridges are symmetrically provided on the inner wall of the upper part of the sleeve (9-1). The ridges can slide up and down along the tracks to realize the up and down sliding of the axial rotating neck 7 relative to the buffer fixed sleeve (9). At the same time, the ridges and the slide rails cooperate to limit the relative position of the axial rotating neck 7 in the circumferential direction and limit the position of the buffer ball 8.

[0044] The above technical solution can provide the spine with a certain degree of flexion, extension and lateral bending. The protrusion design of the upper connecting rod 5 and the angle limit of the lower opening of the lateral bending fixing frame (4-1, 4-2) ensure flexion, extension and lateral bending while limiting excessive movement.

[0045] Compared with the fixation devices used in traditional posterior lumbar decompression and fusion fixation, the present invention can retain appropriate physiological movements in six directions of spinal flexion and extension, scoliosis, and rotation, and avoid the accelerated degeneration of adjacent segments due to loss of mobility of the diseased segment and abnormal changes in spinal biomechanics. Specifically, the scoliosis fixation frame device has an arc-shaped groove in the side wall of the upper fixing rod, which cooperates with a pair of protrusions in the middle of the upper connecting rod to maintain the fixation effect while ensuring appropriate forward flexion and backward extension activities with the help of the rotation of the upper connecting rod itself; the ridges on the side wall of the lower circular ring of the scoliosis fixation frame are the same shape as the outer contour of the scoliosis joint and match each other, and the lower end opening has a certain angle, which can realize the left and right scoliosis of the spine within the physiological range; in addition, the scoliosis joint contains a groove that completely matches the outer contour of the axial rotation neck, which can realize the physiological function of rotation along the axis of the body.

[0046] Preferably, since the elastic modulus of titanium alloy is similar to that of human bones, and titanium alloy has very strong corrosion resistance, and titanium alloy has very good compatibility with the human body, the double-frame fixing screws (2-1, 2-2, 2-3, 2-4), the lateral bending fixing frame (4-1, 4-2), the connecting rod (5), the lateral bending joint (6-1, 6-2), the axial rotation neck (7) and the buffer fixing sleeve (9) can be made of titanium alloy. Alternatively, they can be made of other high-strength hard materials (including but not limited to: PEEK carbon, titanium alloy). The advantage of PEEK material is that it is also compatible with magnetic resonance imaging, that is, no metal artifacts will appear, and better imaging information can be displayed.

[0047] Preferably, the buffer ball (8) is made of polycarbonate polyurethane PCU material (including but not limited to polyurethane PU, silicone, rubber, hydrogel), which can provide shock absorption capability through elastic deformation.

[0048] Preferably, the pedicle screws (1-1, 1-2, 1-3, 1-4) are spinal expandable fixation screws, which can effectively enhance the anchoring effect, especially for patients with osteoporosis and other bone loss. (Including but not limited to: ordinary screws, universal screws)

[0049] The lumbar facet joint function replacement fixation device of the present invention can be applied to prosthetic replacement in posterior laminectomy when actually used. The implementation principle and process are as follows:

[0050] like Figure 1 、 2 The figure shows the normal structure of the lumbar spine in the human body and the resection part of the posterior decompression laminectomy (the resection part is shown as the dotted line). After bilateral laminectomy, the integrity of the facet joints is destroyed, and thus the facet joints' load-bearing, cushioning and spinal stability maintaining functions as well as their function together with the vertebral laminae to protect the contents of the spinal canal are impaired.

[0051] Step 1: Before installing the spinal lumbar facet joint prosthesis, select the appropriate size model based on imaging examination.

[0052] Step 2: Drill holes symmetrically in the pedicles below the interstitial space (see Figure 5 ), and at the same time, a transverse hole is punched on the spinous process of the lower segment of the responsible space; two pedicle screws are implanted in the hole of the pedicle of the lower segment of the responsible space, and the lower connecting rod (10) is passed through the transverse hole of the spinous process and the two supporting columns of the buffer fixing sleeve (9), and the two pedicle screws on the pedicle of the lower segment of the responsible space are fixed to the lower connecting rod (10) respectively with the help of two pedicle auxiliary screws; thereby determining the basic installation position of the device of the present invention.

[0053] Step 3, assemble the scoliosis fixation frame (4-1, 4-2), the upper connecting rod (5), the scoliosis joint (6-1, 6-2) and the axial rotation neck (7) with the help of double frame fixing screws (3-1, 3-2, 3-3, 3-4), and together form a core component, which can be assembled in advance to reduce surgical installation time.

[0054] Step 4, assemble the buffer ball (8) and the core assembly in sequence from the caudal side to the cranial side, and after the installation is completed, determine the drilling position of the pedicle of the upper segment of the responsible gap according to the corresponding height of the upper connecting rod (5) and drill two holes symmetrically;

[0055] Step 5, after the drilling is completed, the remaining two pedicle screws are implanted into the holes of the pedicles of the upper segment of the responsible space, and the two pedicle screws are fixed to the upper connecting rod (5) with the help of the remaining two pedicle auxiliary screws, thereby fixing the core component and completing the installation of the device of the present invention.

[0056] like Figure 5 As shown, once fully fixed, the fixation device allows the treated segment to move in nearly normal six degrees of freedom (flexion and extension, lateral bending, and axial rotation), while also buffering axial pressure and maintaining spinal stability. The complete fixation device, positioned posteriorly in the midline, also serves as a replacement for the vertebral attachments in protecting the spinal canal contents.

[0057] In summary, the present invention restores normal motion and provides stabilization of the spinal segment by replacing it with a functional facet joint replacement fixation device after a facetectomy and nerve decompression procedure. This device is implanted via an open posterior approach and fixed within the pedicle. It is designed to preserve motion, functionally replacing the facet joint while providing immediate alignment and stabilization of the spinal segment at a single spinal level.

[0058] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A lumbar facet joint function replacement fixation device, characterized in that: The invention comprises four identical pedicle screws (1-1, 1-2, 1-3, 1-4), four identical pedicle auxiliary screws (2-1, 2-2, 2-3, 2-4), four identical double-frame fixing screws (3-1, 3-2, 3-3, 3-4), a pair of mirror-symmetrical scoliosis fixing frames (4-1, 4-2), an upper connecting rod (5), a pair of scoliosis joints (6-1, 6-2), an axial rotation neck (7), a buffer ball (8), a buffer fixing sleeve (9) and a lower connecting rod (10); The upper connecting rod (5) and the lower connecting rod (10) are arranged parallel to each other, and both ends of the upper connecting rod (5) are provided with through holes, and the axes of the four through holes are parallel and perpendicular to the upper connecting rod (5); the pedicle screws are fixed to the upper connecting rod (5) or the lower connecting rod (10) by passing the pedicle auxiliary screws through the corresponding through holes; The upper half of the side bending fixing frame (4-1) is a fixing rod with an opening on the side wall, and the lower half is a circular ring with an opening on the bottom. Screw holes are respectively provided at the upper end of the fixing rod, the upper end of the circular ring, and the left and right sides of the middle of the circular ring, and the screw holes match the double-frame fixing screws; the inner wall edge of the circular ring with an opening at the bottom is provided with a ridge along the circumferential direction; the two side bending fixing frames (4-1, 4-2) are relatively superimposed and installed at the midpoint of the upper connecting rod (5), and the openings on the fixing rods of the two are relatively formed to form a circular ring sleeved outside the connecting rod (5). The screw holes at their corresponding positions are connected and are fixed by four double-frame fixing screws (3-1, 3-2, 3-3, 3-4) passing through them respectively; at the same time, arc-shaped grooves are provided on the inner walls of the openings of the fixing rods of the two lateral bending fixing frames (4-1, 4-2), and protrusions are provided on both sides of the upper connecting rod (5), and the two protrusions can slide in the corresponding arc-shaped grooves, so that the fixing frame formed by the two lateral bending fixing frames (4-1, 4-2) can rotate around the upper connecting rod (5) within a certain arc range; The side bending joint (6) comprises a left half (6-1) and a right half (6-2), both of which are half cylinders with flush bottom ends, and the left half (6-1) and the right half (6-2) are correspondingly buckled together through a plurality of insertion rods and holes provided on opposite side walls to form a cylinder with a flush bottom end; grooves are respectively provided on the edges of the arc surface of the cylinder along the circumferential direction, and the two grooves correspond in position and shape to the two ridges on the inner wall of the circular ring of the lower half of the side bending fixing frame (4-1), and the ridges can slide relatively along the grooves in which they are located; The axial rotating neck (7) is a stepped cylinder with a larger upper portion and a smaller lower portion. The side walls of the left half (6-1) and the right half (6-2) of the lateral bending joint (6) that contact each other are respectively provided with grooves matching the shape of the upper half of the axial rotating neck (7). The upper half of the axial rotating neck (7) is installed in the groove and can rotate around its own axis relative to the groove. The lower end of the axial rotating neck (7) extends out of the lateral bending joint (6). The buffer fixing sleeve (9) comprises a sleeve upper part (9-1) and a sleeve lower part (9-2) connected to each other. The sleeve upper part (9-1) is a cylindrical body with an open upper end and a closed lower end. The lower end of the axial rotating neck (7) is inserted into the sleeve upper part (9-1) and can move up and down. The sleeve lower part (9-2) is a bifurcated structure composed of two support columns, and lower connecting rod sleeves are respectively provided at both ends of the bifurcated structure. The lower connecting rod sleeves are respectively sleeved on the lower connecting rod (10) to achieve fixation. The two support columns and the lower connecting rod (10) form a triangle.

2. The lumbar facet joint function replacement fixation device according to claim 1, characterized in that: A U-shaped opening is provided on the non-threaded end of the pedicle screw, and a threaded hole matching the pedicle auxiliary screw is provided at the bottom of the U-shaped opening. The U-shaped opening is used to insert the upper connecting rod (5) or the lower connecting rod (10) therein, and the pedicle auxiliary screw passes through the screw hole of the upper connecting rod (5) or the lower connecting rod (10) and enters the threaded hole, thereby fixing the upper connecting rod (5) or the lower connecting rod (10) to the corresponding pedicle screw.

3. The lumbar facet joint function replacement fixation device according to claim 1, characterized in that: Four convex strips with a length of three-quarters of the lower connecting rod are evenly arranged along the circumference in the middle of the side wall of the lower connecting rod (10), and the length direction of the convex strips is consistent with the length direction of the lower connecting rod (10); the convex strips are matched one-to-one with multiple grooves arranged on the inner wall of the support column of the lower part (9-2) of the sleeve.

4. The lumbar facet joint function replacement fixation device according to claim 1, characterized in that: The lower end of the axial rotating neck (7) is separated from the buffer fixing sleeve (9) by a buffering ball (8).

5. The lumbar facet joint function replacement fixation device according to claim 1, characterized in that: Two convex strips are symmetrically provided on the side wall of the lower end of the axial rotating neck (7), and two tracks matching the convex strips are symmetrically provided on the inner wall of the upper part (9-1) of the sleeve. The convex strips can slide up and down along the tracks to realize the axial rotating neck 7 sliding up and down relative to the buffer fixed sleeve (9).

6. The lumbar facet joint function replacement fixation device according to claim 1, characterized in that: The double-frame fixing screws (2-1, 2-2, 2-3, 2-4), lateral bending fixing frames (4-1, 4-2), connecting rods (5), lateral bending joints (6-1, 6-2), axial rotation necks (7) and buffer fixing sleeves (9) are made of titanium alloy, PEEK carbon or titanium alloy.

7. The lumbar facet joint function replacement fixation device according to claim 1, characterized in that: The buffer ball (8) is made of polycarbonate polyurethane PCU material, polyurethane PU, silica gel, rubber, or hydrogel.

8. The lumbar facet joint function replacement fixation device according to claim 1, characterized in that: The pedicle screws (1-1, 1-2, 1-3, 1-4) are spinal expansion type fixation screws.

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