Implants for posterior lumbar joint replacement surgery

Abstract

The application provides a lumbar posterior joint replacement surgery implant provided with an external connecting assembly, the external connecting assembly comprising an upper connecting assembly and a lower connecting assembly, the middle position of the upper connecting assembly being provided with an upper connecting cover plate, the middle position of the lower connecting assembly being provided with a lower connecting cover plate, the inner side position of the bottom end surface of the upper connecting cover plate being provided with an upper movable boss, and the inner side position of the top end surface of the lower connecting cover plate being provided with a lower movable boss. The application solves the problem that the existing intervertebral fusion cage does not have a structure for assisting the movement of the vertebral body, leading to rigid fixation between adjacent vertebral bodies, so that the adjacent vertebral bodies cannot move relative to each other after the surgery, and only other lumbar segments can be used to complete the local movement of the lumbar vertebrae, reducing the overall movement range of the lumbar vertebrae, increasing the transmission load of the lumbar vertebrae, and causing the patient to be unable to perform normal side bending, flexion and extension movements after the surgery. The application can be widely applied to lumbar posterior joint replacement surgery.

Description

Technical Field

[0001] This invention relates to a posterior lumbar spine joint replacement surgery, and more particularly to an implant for posterior lumbar spine joint replacement surgery. Background Technology

[0003] Lumbar spinal stenosis or lumbar spondylolisthesis, whether caused by congenital or acquired factors, can lead to a series of symptoms such as compression of lumbar nerve tissue, impaired blood circulation, lower limb pain, neurogenic claudication, and back pain.

[0004] Lumbar fusion is a recognized surgical method for treating lumbar spinal stenosis or spondylolisthesis. Current lumbar fusion surgery involves placing an interbody fusion cage between adjacent vertebrae and then using pedicle screws and connecting rods to fix the affected vertebrae, thereby restoring the normal physiological curve of the adjacent vertebrae. However, because the existing interbody fusion cages have a simple structure and lack structures to assist the movement of the lumbar vertebrae, they result in rigid fixation between adjacent vertebrae. After surgery, the adjacent vertebrae cannot move relative to each other, and the lumbar spine can only move locally through other lumbar segments, reducing the overall range of motion of the lumbar spine and increasing the load transmitted to the lumbar spine. Ultimately, this leads to the patient's inability to perform normal lateral bending, flexion and extension movements after surgery. Summary of the Invention

[0006] To address the above-mentioned technical problems, this invention provides an implant for posterior lumbar spine arthroplasty. This implant has an internal structure that assists in the movement of the lumbar vertebrae, enabling flexible fixation between adjacent vertebrae. The adjacent vertebrae can move relative to each other without affecting the overall range of motion of the lumbar spine, reducing the transmitted load on the lumbar spine. After surgery, the patient's lumbar spine can perform normal lateral bending, flexion and extension movements.

[0007] Therefore, the technical solution of the present invention is an implant for posterior lumbar spine joint replacement surgery, which is provided with an external connection component. The external connection component includes an upper connection component and a lower connection component. An upper connection cover plate is provided in the middle position of the upper connection component. Upper connection rods are symmetrically fixed on both sides of the upper connection cover plate. An upper clearance groove is provided in the middle position of the top end face of the outer surface of the upper connection cover plate. A longitudinal through hole is provided on the upper connection cover plate. The lower connecting assembly has a lower connecting cover plate in the middle position, and lower connecting rods are symmetrically fixed on both sides of the lower connecting cover plate. The outer surface of the lower connecting cover plate has a lower clearance groove in the middle position of the bottom end face, and the lower connecting cover plate has a longitudinal through hole. The upper and lower connecting rods are equipped with pedicle screws; The outermost position of the bottom end face of the upper connecting cover plate is fixed downward with an upper fixing groove, the opening of the upper fixing groove is set towards the upper movable boss, and the outermost position of the top end face of the lower connecting cover plate is fixed upward with a lower fixing groove, the opening of the lower fixing groove is set towards the lower movable boss, and an elastic protective sleeve is fixedly connected between the upper connecting cover plate and the lower connecting cover plate. The elastic protective sleeve has a middle connecting section in the middle position. The middle connecting section bends outward in a free state. The upper and lower ends of the middle connecting section are respectively fixed with an upper fixing section and a lower fixing section. The outermost positions of the upper and lower fixing sections are respectively fixed with an upper fixing boss and a lower fixing boss. The upper and lower fixing bosses protrude outward along the circumferential direction. The upper fixing boss and the upper fixing groove are circumferentially fixedly connected. The lower fixing boss and the lower fixing groove are circumferentially fixedly connected. The upper connecting cover and the lower connecting cover can swing relative to each other in the circumferential direction. When the upper connecting cover and the lower connecting cover swing relative to each other in the circumferential direction, the elastic protective sleeve can undergo elastic deformation. A sealed internal cavity is formed between the bottom end face of the upper connecting cover plate, the top end face of the lower connecting cover plate, and the elastic protective sleeve. An upper movable boss is fixedly provided on the inner side of the bottom end face of the upper connecting cover plate. The upper movable boss is vertically set downward relative to the upper connecting cover plate and has a sheet-like structure. The front end of the upper movable boss has a front sliding section and the rear end of the upper movable boss has a rear support section. A lower movable boss is fixedly provided on the inner side of the top end face of the lower connecting cover plate. The lower movable boss is vertically set upward relative to the lower connecting cover plate and has a sheet-like structure. The front end of the lower movable boss has a front guide section and a guide arc surface on one side of the outer surface of the front guide section. The rear end of the lower movable boss has a rear support section. One side plane of the front sliding section on the upper movable boss and the guide arc surface on the front guide section on the lower movable boss are in contact with each other. When the upper connecting cover plate and the lower connecting cover plate swing relative to each other in the circumferential direction, one side plane of the front sliding section on the upper movable boss and the guide arc surface on the front guide section on the lower movable boss always maintain contact and slide relative to each other. An upper support limiting block is fixedly provided on the bottom end face of the upper connecting cover plate. The outer circumference of the upper support limiting block and the inner surface of the upper fixed section of the elastic protective sleeve are circumferentially fixedly connected. A longitudinal through support limiting hole is provided on one side of the upper support limiting block. The upper movable boss passes through the support limiting hole. The plane on the side away from the guide arc surface on the lower movable boss of the rear support section of the upper movable boss is laterally fixedly connected to the inner surface on one side of the support limiting hole. A lower movable boss limiting hole is provided between the plane on the side of the rear support section of the upper movable boss close to the guide arc surface on the lower movable boss and the inner surface on the other side of the support limiting hole. The lower movable boss limiting hole is located at the longitudinal extension position of the lower movable boss. A longitudinal threaded hole is provided on the top of the upper support limiting block. The upper support limiting block is locked and fixed by a locking screw passing through the through hole on the upper connecting cover plate and the threaded hole on the upper support limiting block, thus longitudinally locking the upper support limiting block and the upper connecting cover plate. A lower support limiting block is fixedly provided on the top end face of the lower connecting cover plate. The outer circumference of the lower support limiting block and the inner surface of the lower fixed section of the elastic protective sleeve are circumferentially fixedly connected. A longitudinal through-hole for fixing the lower movable boss is provided on one side of the lower support limiting block. The lower movable boss passes through the lower movable boss fixing hole. The outer surface of the rear support section on the lower movable boss and the inner surface of the lower movable boss fixing hole are transversely fixedly connected. The top of the lower support limiting block is provided with an upper movable boss limiting groove located at the longitudinal position of the upper movable boss. The upper movable boss limiting groove is located at the longitudinal extension position of the upper movable boss. A longitudinal threaded hole is provided at the bottom of the lower support limiting block. The lower support limiting block is locked and fixed by a locking screw passing through the through hole on the lower connecting cover plate and the threaded hole on the lower support limiting block, thus longitudinally locking the lower support limiting block and the lower connecting cover plate.

[0008] Preferably, a limiting band is fixedly provided between the outer circumference of the upper support limiting block at a laterally symmetrical position on the side of the upper movable boss away from the lower movable boss and the outer circumference of the lower support limiting block at a longitudinally symmetrical position relative to the outer circumference of the upper support limiting block. The limiting band includes a limiting band connecting section, and a limiting band telescopic section is provided at the middle position of the limiting band connecting section. The upper end face of the limiting band connecting section is laterally fixedly connected to the outer circumference of the upper support limiting block, and the lower end face of the limiting band connecting section is laterally fixedly connected to the outer circumference of the lower support limiting block.

[0009] Preferably, the internal receiving cavity is provided at the position of the bending arc of the middle connecting section, and the limiting band telescopic section bends outward in a free state, and the limiting band telescopic section is located inside the limiting band receiving cavity.

[0010] Preferably, the upper and lower ends of the limiting band connecting section are respectively connected and fixedly provided with an upper fixing section and a lower fixing section. The upper fixing section is located between the upper support limiting block and the upper connecting cover plate. The upper connecting cover plate, the upper fixing section of the limiting band and the upper support limiting block are longitudinally fixedly connected. The lower fixing section of the limiting band is located between the lower support limiting block and the lower connecting cover plate. The lower connecting cover plate, the lower fixing section of the limiting band and the lower support limiting block are longitudinally fixedly connected.

[0011] Preferably, the width of the limiting band is 6mm ± 1mm ​​and the thickness of the limiting band is 1mm ± 0.2mm.

[0012] Preferably, the top end face of the upper support limiting block is provided with an upper fixing groove at the position where it is fixedly connected to the upper fixing section of the limiting band, and the upper fixing groove, the upper fixing section of the limiting band, and the upper connecting cover plate are longitudinally fixedly connected. The bottom end face of the lower support limiting block is provided with a lower fixing groove at the position where it is fixedly connected to the lower fixing section of the limiting band, and the lower fixing groove, the lower fixing section of the limiting band, and the lower connecting cover plate are longitudinally fixedly connected.

[0013] Preferably, a guide wear-resistant sleeve is fixedly provided on the outer surface of the lower movable boss. A middle support section of the guide wear-resistant sleeve is provided in the middle position of the guide wear-resistant sleeve. An upper guide section of the guide wear-resistant sleeve is fixedly provided at the upper end of the middle support section of the guide wear-resistant sleeve. A guide arc surface is provided on one side of the outer surface of the upper guide section of the guide wear-resistant sleeve. The front sliding section of the upper movable boss is in contact with the side plane of the lower movable boss and the guide arc surface on the upper guide section of the guide wear-resistant sleeve. When the upper connecting cover plate and the lower connecting cover plate swing relative to each other in the circumferential direction, the front sliding section of the upper movable boss is always in contact with the side plane of the lower movable boss and the guide arc surface on the upper guide section of the guide wear-resistant sleeve and slides relative to each other. The lower end of the intermediate support section of the guide wear-resistant sleeve is fixedly provided with a lower fixing section of the guide wear-resistant sleeve. The lower fixing section of the guide wear-resistant sleeve is located at the lower end of the intermediate support section of the guide wear-resistant sleeve and is arranged laterally outward. The outermost position of the lower fixing section of the guide wear-resistant sleeve is fixedly provided with a lower fixing boss of the guide wear-resistant sleeve. The lower fixing boss of the guide wear-resistant sleeve protrudes upward. The inner surface of the fixing hole of the lower movable boss is laterally fixedly connected to the outer surface of the intermediate support section of the guide wear-resistant sleeve. The bottom end face of the lower support limiting block is provided with guide wear-resistant sleeve fixing grooves on both sides of the fixing hole of the lower movable boss. The opening direction of the guide wear-resistant sleeve fixing grooves is set downward. The guide wear-resistant sleeve fixing grooves and the lower fixing boss of the guide wear-resistant sleeve are longitudinally fixedly connected.

[0014] Preferably, the pedicle screw includes a head, a screw rod fixedly mounted at the bottom end of the head, an external thread on the outer circumference of the screw rod, a connecting rod fixing groove on the head, an internal thread on the inner surface of the connecting rod fixing groove, a fixing set screw fixedly mounted inside the connecting rod fixing groove, an external thread on the outer surface of the fixing set screw, and a threaded connection between the external thread on the outer surface of the fixing set screw and the internal thread on the inner surface of the connecting rod fixing groove. An upper connecting rod and a lower connecting rod are respectively fixed between the fixing set screw and the bottom end of the connecting rod fixing groove. The upper connecting rod and the lower connecting rod are longitudinally locked by the threaded locking between the fixing set screw and the head.

[0015] Preferably, the thickness of the front sliding section on the upper movable boss is 1.5mm ± 0.3mm, and the thickness of the rear support section on the lower movable boss is 3mm ± 0.5mm. The rear end of the upper movable boss has a reinforced support surface near the limiting hole of the lower movable boss, forming an inverted trapezoidal structure. The longitudinal inclination angle of the reinforced support surface is 8.5°±0.5°.

[0016] Preferably, the upper connecting rod and the upper connecting cover plate are integrally formed, and the lower connecting rod and the lower connecting cover plate are integrally formed. The length of the upper connecting rod and the lower connecting rod is 28mm±1mm, the outer diameter of the upper connecting rod and the lower connecting rod is 5mm±0.5mm, the included angle between the two upper connecting rods is 140°±2°, and the included angle between the two lower connecting rods is 140°±2°.

[0017] The beneficial effects of this invention are: 1. By fixing an upper support limiting block and a lower support limiting block to the inner surfaces of the upper and lower fixing sections of the elastic protective sleeve, respectively, the upper and lower support limiting blocks circumferentially lock the upper and lower fixing sections of the elastic protective sleeve, thereby preventing the elastic protective sleeve from falling off the upper or lower connecting cover plate due to frequent movement of the upper and lower connecting components. This increases the stability of the implant movement and extends its service life. Furthermore, by setting a lower movable boss limiting hole and an upper movable boss limiting groove on the upper support limiting block and the lower support limiting block respectively, the longitudinal compression amplitude of the upper movable boss and the lower movable boss can be controlled, avoiding the problem of adjacent vertebral bodies being squeezed and dislocated due to excessive compression amplitude of the upper movable boss and the lower movable boss.

[0018] 2. By fixing a limiting band between the upper and lower support limiting blocks, the limiting band can control the opening angle between the upper and lower support limiting blocks, preventing the opening angle between the upper and lower support limiting blocks from being too large, which could cause secondary damage to adjacent vertebrae or even serious problems such as dislocation of connected vertebrae.

[0019] 3. By fixing a guide wear-resistant sleeve on the outer surface of the lower movable boss, and the guide wear-resistant sleeve having a guide arc surface, firstly, when the vertebral body performs bending movements, the upper movable boss slides along the guide arc surface. Since the guide arc surface is designed to conform to the normal physiological curvature of the human vertebral body, it plays a guiding role in the lumbar flexion of the patient after surgery, thereby reducing the transmitted load force of the lumbar spine. Secondly, the guide wear-resistant sleeve is made of wear-resistant material, which can increase the wear resistance of the wear-resistant sleeve. When the upper movable boss slides and rubs along the guide arc surface for a long time, the guide arc surface on the wear-resistant sleeve can also maintain the initial curvature for a long time. Furthermore, by using wear-resistant material for the guide wear-resistant sleeve, the debris generated by friction between the upper movable boss and the wear-resistant sleeve can be reduced.

[0020] 4. By providing an internal receiving cavity between the bottom end face of the upper connecting cover plate, the top end face of the lower connecting cover plate, and the elastic protective sleeve, when the upper movable boss slides and rubs against the outer surface of the guide wear-resistant sleeve, the generated debris can be blocked inside the internal receiving cavity, preventing the generated debris from falling into other parts around the vertebral body and causing secondary infection damage to other parts around the vertebral body.

[0021] 5. By providing upper and lower clearance grooves on the outer surfaces of the upper and lower connecting cover plates, the upper and lower clearance grooves can avoid the spinous processes of adjacent vertebrae during implantation, thus preventing friction and collision with the spinous processes of the vertebrae. Attached Figure Description

[0023] Figure 1 This is a three-dimensional diagram showing the application effect of the present invention; Figure 2 This is a perspective view of the present invention; Figure 3 This is the main view of the present invention; Figure 4 This is a top view of the present invention; Figure 5 This is the present invention. Figure 4 BB section view; Figure 6 This is a front view of the elastic protective sleeve in this invention; Figure 7 This is the present invention. Figure 6 CC section view; Figure 8This is a perspective view of the limiting band in this invention; Figure 9 This is a perspective view of the upper support limiting block in this invention; Figure 10 This is a perspective view of the lower support limiting block in this invention; Figure 11 This is another perspective view of the lower support limiting block in this invention; Figure 12 This is a perspective view of the upper connecting component in this invention; Figure 13 This is the main view of the upper connecting component in this invention; Figure 14 This is a bottom view of the upper connecting component in this invention; Figure 15 This is a perspective view of the lower connecting component in this invention; Figure 16 This is the main view of the lower connecting component in this invention; Figure 17 This is a bottom view of the lower connecting component in this invention; Figure 18 This is the present invention. Figure 5 Enlarged view at point D; Figure 19 This is the present invention. Figure 5 Enlarged view at point E in the middle; Figure 20 This is the present invention. Figure 14 DD section view; Figure 21 This is the present invention. Figure 17 EE section view; Figure 22 This is a three-dimensional view of the pedicle screw of the present invention.

[0024] Explanation of symbols in the diagram: 1. External connecting assembly; 101. Upper connecting assembly; 10101. Upper connecting rod; 10102. Upper clearance groove; 10103. Upper movable boss; 1010301. Front sliding section; 1010302. Rear support section; 1010303. Reinforcing support surface; 10104. Through hole; 10105. Upper fixing groove; 10106. Upper connecting cover plate; 102. Lower connecting assembly; 10201. Lower connecting rod; 10202. Lower clearance groove; 10203. Lower movable boss 1. Moving boss; 1020301. Front guide section; 1020302. Rear support section; 1020303. Guide arc surface; 10204. Through hole; 10205. Lower fixing groove; 10206. Lower connecting cover plate; 2. Elastic protective sleeve; 201. Middle connecting section of elastic protective sleeve; 202. Upper fixing section of elastic protective sleeve; 20201. Upper fixing boss of elastic protective sleeve; 203. Lower fixing section of elastic protective sleeve; 20301. Lower fixing boss of elastic protective sleeve; 204. Limiting band accommodating 3. Vertebral body; 301. Vertebral spinous process; 302. Pedicle; 4. Pedicle screw; 401. Screw head; 402. Thread; 403. Fixing set screw; 404. Connecting rod fixing groove; 405. Internal thread; 5. Locking screw; 6. Upper support limiting block; 601. Upper fixing groove; 602. Support limiting hole; 60201. Lower movable boss limiting hole; 604. Threaded hole; 7. Lower support limiting block; 701. Lower fixing groove; 702. Upper movable boss limiting groove; 703. Lower... 704. Threaded hole; 705. Guide wear-resistant sleeve fixing groove; 8. Guide wear-resistant sleeve; 801. Guide wear-resistant sleeve intermediate support section; 802. Guide wear-resistant sleeve lower fixing section; 80201. Guide wear-resistant sleeve lower fixing boss; 803. Guide wear-resistant sleeve upper guide section; 80301. Guide arc surface; 9. Limiting band; 901. Limiting band connecting section; 90101. Limiting band telescopic section; 902. Limiting band upper fixing section; 903. Limiting band lower fixing section; 10. Internal receiving cavity. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments.

[0027] pass Figures 1-22As can be seen, the implant for posterior lumbar spine joint replacement surgery is provided with an external connecting component 1. The external connecting component 1 includes an upper connecting component 101 and a lower connecting component 102. An upper connecting cover plate 10106 is provided in the middle position of the upper connecting component 101. Upper connecting rods 10101 are symmetrically fixed on both sides of the upper connecting cover plate 10106. An upper clearance groove 10102 is provided in the middle position of the top end face of the outer surface of the upper connecting cover plate 10106. A longitudinal through hole 10104 is provided on the upper connecting cover plate 10106.

[0028] The lower connecting assembly 102 has a lower connecting cover plate 10206 in the middle position. Lower connecting rods 10201 are symmetrically fixed on both sides of the lower connecting cover plate 10206. The lower connecting cover plate 10206 has a lower clearance groove 10202 in the middle position of the bottom end face on its outer surface. The lower connecting cover plate 10206 has a longitudinal through hole 10204. When the implant is installed, the upper clearance groove 10102 and the lower clearance groove 10202 can avoid the spinous process 301 of the adjacent vertebral body, so as to avoid friction and collision with the spinous process 301.

[0029] The upper connecting rod 10101 and the lower connecting rod 10201 are equipped with pedicle screws 4.

[0030] An upper fixing groove 10105 is fixedly provided downward at the outermost position of the bottom end face of the upper connecting cover plate 10106. The opening of the upper fixing groove 10105 is set towards the upper movable boss 10103. A lower fixing groove 10205 is fixedly provided upward at the outermost position of the top end face of the lower connecting cover plate 10206. The opening of the lower fixing groove 10205 is set towards the lower movable boss 10203. An elastic protective sleeve 2 is fixedly connected between the upper connecting cover plate 10106 and the lower connecting cover plate 10206.

[0031] The elastic protective sleeve 2 has a middle connecting section 201 at its middle position. The middle connecting section 201 bends outwards in a free state. An upper fixing section 202 and a lower fixing section 203 are fixed to the upper and lower ends of the middle connecting section 201, respectively. An upper fixing boss 20201 and a lower fixing boss 20301 are fixed to the outermost positions of the upper fixing section 202 and the lower fixing section 203, respectively. The upper fixing boss 20201... 201 and the lower fixing boss 20301 of the elastic protective sleeve protrude outward along the circumferential direction respectively. The upper fixing boss 20201 and the upper fixing groove 10105 of the elastic protective sleeve are circumferentially fixedly connected. The lower fixing boss 20301 and the lower fixing groove 10205 of the elastic protective sleeve are circumferentially fixedly connected. The upper connecting cover plate 10106 and the lower connecting cover plate 10206 can swing relative to each other along the circumferential direction. When the upper connecting cover plate 10106 and the lower connecting cover plate 10206 swing relative to each other along the circumferential direction, the elastic protective sleeve 2 can undergo elastic deformation.

[0032] Furthermore, due to the outward bending arc of the middle connecting section 201 on the elastic protective sleeve 2 in its free state, the structural design of this bending arc can provide sufficient expansion and contraction when the upper connecting cover 10106 and the lower connecting cover 10206 open and close. In addition, due to the outward bending arc of the middle connecting section 201 in its free state, the stability of the support between the upper connecting cover 10106 and the lower connecting cover 10206 can be increased, and effective support strength can be maintained even when the upper connecting cover 10106 and the lower connecting cover 10206 move frequently.

[0033] A sealed internal cavity 10 is formed between the bottom end face of the upper connecting cover plate 10106, the top end face of the lower connecting cover plate 10206, and the elastic protective sleeve 2. This internal cavity 10 can be used to contain the debris generated by the friction between the upper movable protrusion 10103 and the lower movable protrusion 10203 during the use of the implant, preventing the debris from falling to other parts of the vertebral body and causing secondary damage to other parts.

[0034] An upper movable boss 10103 is fixedly provided on the inner side of the bottom end face of the upper connecting cover plate 10106. The upper movable boss 10103 is vertically arranged downward relative to the upper connecting cover plate 10106. The upper movable boss 10103 has a sheet-like structure. A front sliding section 1010301 is provided at the front end of the upper movable boss 10103, and a rear support section 1010302 is provided at the rear end of the upper movable boss 10103. A lower movable boss 10203 is fixedly provided on the inner side of the top end face of the lower connecting cover plate 10206. The lower movable boss 10203 is vertically arranged upward relative to the lower connecting cover plate 10206. The lower movable boss 10203 has a sheet-like structure, and a front guide section 10203 is provided at the front end of the lower movable boss 10203. 01. One side of the outer surface of the front guide section 1020301 is provided with a guide arc surface 1020303. The rear end of the lower movable boss 10203 is provided with a rear support section 1020302. One side plane of the front sliding section 1010301 on the upper movable boss 10103 and the guide arc surface 1020303 on the front guide section 1020301 on the lower movable boss 10203 are in contact with each other. When the upper connecting cover plate 10106 and the lower connecting cover plate 10206 swing relative to each other in the circumferential direction, the one side plane of the front sliding section 1010301 on the upper movable boss 10103 and the guide arc surface 1020303 on the front guide section 1020301 on the lower movable boss 10203 always remain in contact and slide relative to each other.

[0035] The curvature of the guide arc surface 1020303 is the normal physiological curvature of the human vertebral body. When the lumbar spine bends forward and backward, the front sliding segment 1010301 on the upper movable protrusion 10103 slides up and down along the guide arc surface 1020303, which plays a guiding role in the lumbar spine curvature after the operation of the patient, thereby reducing the transmitted load force of the lumbar spine.

[0036] Since both the upper movable boss 10103 and the lower movable boss 10203 are plate-like structures, the contact end surface area can be increased, thereby increasing the sliding stability between the upper movable boss 10103 and the lower movable boss 10203.

[0037] An upper support limiting block 6 is fixedly provided on the bottom end face of the upper connecting cover plate 10106. The outer circumference of the upper support limiting block 6 is circumferentially fixedly connected to the inner surface of the upper fixed section 202 of the elastic protective sleeve, which avoids the problem of the elastic protective sleeve 2 falling off the upper connecting cover plate 10106 due to frequent movement of the upper connecting assembly 101, increases the stability of the implant movement, and extends its service life. A longitudinally penetrating support limiting hole 602 is provided on one side of the upper support limiting block 6, and the upper movable boss 10103 passes through the support limiting hole 602. The rear end support section 1010302 on the upper movable boss 10103 is laterally fixedly connected to the inner surface of one side of the guide arc surface 1020303 on the lower movable boss 10203, which can prevent the upper movable boss 10103 from sliding up and down along the guide arc surface 1020303. The reverse force generated by 10103 causes lateral swaying when the upper movable boss 10103 slides up and down, further improving the stability of the upper movable boss 10103. The rear support section 1010302 on the upper movable boss 10103 is provided with a lower movable boss limiting hole 60201 between one side plane of the guide arc surface 1020303 on the lower movable boss 10203 and the other side inner surface of the support limiting hole 602. The lower movable boss limiting hole 60201 is located at the longitudinal extension position of the lower movable boss 10203. The top of the upper support limiting block 6 is provided with a longitudinal threaded hole 604. The upper support limiting block 6 is locked and fixed by the locking screw 5 through the through hole 10104 on the upper connecting cover plate 10106 and the threaded hole 604 on the upper support limiting block 6, thus longitudinally locking the upper support limiting block 6 and the upper connecting cover plate 10106.

[0038] A lower support limiting block 7 is fixedly provided on the top end face of the lower connecting cover plate 10206. The outer circumference of the lower support limiting block 7 is circumferentially fixed to the inner surface of the lower fixing section 203 of the elastic protective sleeve, which avoids the problem of the elastic protective sleeve 2 falling off the lower connecting cover plate 10206 due to frequent movement of the lower connecting assembly 102, increases the stability of the implant movement, and extends its service life. A longitudinally penetrating lower movable boss fixing hole 703 is provided on one side of the lower support limiting block 7. The lower movable boss 10203 passes through the lower movable boss fixing hole 703. The rear support section 1020302 on the lower movable boss 10203 The outer surface of the lower support limiting block 7 is horizontally fixedly connected to the inner surface of the lower movable boss fixing hole 703. The top of the lower support limiting block 7 is provided with an upper movable boss limiting groove 702 located at the longitudinal position of the upper movable boss 10103. The upper movable boss limiting groove 702 is located at the longitudinal extension position of the upper movable boss 10103. The bottom of the lower support limiting block 7 is provided with a longitudinal threaded hole 704. The lower support limiting block 7 is locked and fixed by a locking screw 5 passing through the through hole 10204 on the lower connecting cover plate 10206 and the threaded hole 704 on the lower support limiting block 7, thereby longitudinally locking the lower support limiting block 7 and the lower connecting cover plate 10206.

[0039] By setting a lower movable boss limiting hole 60201 and an upper movable boss limiting groove 702 on the upper support limiting block 6 and the lower support limiting block 7 respectively, the range of motion of the upper movable boss 10103 and the lower movable boss 10203 can be controlled within the lower movable boss limiting hole 60201 and the upper movable boss limiting groove 702 respectively, thus avoiding the problem of dislocation of adjacent vertebrae due to excessive longitudinal movement of the upper movable boss 10103 and the lower movable boss 10203.

[0040] A limiting band 9 is fixedly provided between the outer circumference of the upper support limiting block 6 and the plane on the side of the upper movable boss 10103 away from the lower movable boss 10203, which is laterally symmetrical, and the outer circumference of the lower support limiting block 7 relative to the outer circumference of the upper support limiting block 6. The limiting band 9 includes a limiting band connecting section 901. A limiting band telescopic section 90101 is provided in the middle of the limiting band connecting section 901. The upper end face of the limiting band connecting section 901 is laterally fixedly connected to the outer circumference of the upper support limiting block 6, and the lower end face of the limiting band connecting section 901 is laterally fixedly connected to the outer circumference of the lower support limiting block 7.

[0041] The limiting band 9 can control the opening angle between the upper supporting limiting block 6 and the lower supporting limiting block 7, preventing the opening angle between the upper supporting limiting block 6 and the lower supporting limiting block 7 from being too large, which could lead to excessive stretching between adjacent vertebrae or even serious problems such as dislocation between connected vertebrae.

[0042] The internal receiving cavity 10 is located at the curved arc of the intermediate connecting section 201, and a limiting band receiving cavity 204 is provided. The limiting band telescopic section 90101 bends outward in its free state. The limiting band telescopic section 90101 is located inside the limiting band receiving cavity 204. This prevents the limiting band telescopic section 90101 from bending inward or accumulating inward in its free state or under compression state, and from entering the position between the upper supporting limiting block 6 and the lower supporting limiting block 7, or even entering the upper movable boss 10103 and the lower movable boss 10203. This reduces the amount of compression between the upper supporting limiting block 6 and the lower supporting limiting block 7, and also reduces the accuracy of the sliding guidance when the upper movable boss 10103 slides along the guide arc surface on the lower movable boss 10203. This further affects the smoothness of the patient's lumbar forward bending, backward bending and lateral rotation movements after surgery.

[0043] Regarding the structural features of the limiting band 9, a more preferred solution is that the upper and lower ends of the limiting band connecting section 901 are respectively connected and fixedly provided with an upper fixing section 902 and a lower fixing section 903. The upper fixing section 902 is located between the upper supporting limiting block 6 and the upper connecting cover plate 10106, and the upper connecting cover plate 10106, the upper fixing section 902, and the upper supporting limiting block 6 are longitudinally fixedly connected. The lower fixing section 903 is located between the lower supporting limiting block 7 and the lower connecting cover plate 10206, and the lower connecting cover plate 10206, the lower fixing section 903, and the lower supporting limiting block 7 are longitudinally fixedly connected. This can further avoid the problem of the limiting band 9 falling off due to an excessively large opening angle between the upper supporting limiting block 6 and the lower supporting limiting block 7, increase the stability of the implant movement, and extend its service life.

[0044] The width of the limiting band 9 is 6mm ± 1mm, and the thickness is 1mm ± 0.2mm. This ensures that the limiting band 9 can bend smoothly into the limiting band receiving cavity 204 in both free and compressed states. If the limiting band 9 is too thin, its rebound stability will decrease. When the implant is used for a long time, the limiting band 9 will be frequently stretched due to the frequent opening and compression of the upper supporting limiting block 6 and the lower supporting limiting block 7. This will cause the overall length of the limiting band 9 to increase, resulting in a larger opening angle of the upper supporting limiting block 6 and the lower supporting limiting block 7. Ultimately, this will cause the patient's maximum forward bending angle to exceed the safe angle range, and may even lead to the dislocation of adjacent vertebrae. If the limiting band 9 is too thick, its bending flexibility will decrease, increasing the resistance between the upper supporting limiting block 6 and the lower supporting limiting block 7 when they open and compress. The patient will need to exert more force after surgery to meet the normal lumbar curvature, which will unnecessarily hinder the patient's lumbar movement after surgery.

[0045] Regarding the structural features of the upper support limiting block 6 and the lower support limiting block 7, a more preferred solution is that the top end face of the upper support limiting block 6 is provided with an upper fixing groove 601 at the position where it is fixedly connected to the upper fixing section 902 of the limiting band, and the upper fixing groove 601, the upper fixing section 902 of the limiting band, and the upper connecting cover plate 10106 are longitudinally fixedly connected. The bottom end face of the lower support limiting block 7 is provided with a lower fixing groove 701 at the position where it is fixedly connected to the lower fixing section 903 of the limiting band, and the lower fixing groove 701, the lower fixing section 903 of the limiting band, and the lower connecting cover plate 10206 are longitudinally fixedly connected.

[0046] The upper fixing groove 601 and the lower fixing groove 701 can further increase the friction between the upper fixing section 902 of the limiting band and the upper support limiting block 6, as well as the friction between the lower fixing section 903 of the limiting band and the lower support limiting block 7. This further avoids the problem of the limiting band 9 falling off due to the frequent opening of the upper support limiting block 6 and the lower support limiting block 7, increases the stability of the implant movement, and extends its service life.

[0047] Regarding the structural characteristics of the upper movable boss 10103 and the lower movable boss 10203, a more preferred solution is that a guide wear-resistant sleeve 8 is fixedly provided on the outer surface of the lower movable boss 10203, a guide wear-resistant sleeve intermediate support section 801 is provided in the middle of the guide wear-resistant sleeve 8, an upper guide section 803 is fixedly provided at the upper end of the guide wear-resistant sleeve intermediate support section 801, a guide arc surface 80301 is provided on one side of the outer surface of the upper guide section 803, and a front sliding section on the upper movable boss 10103... The plane of the upper movable boss 1010301 near the lower movable boss 10203 and the guide arc surface 80301 on the upper guide section 803 of the guide wear-resistant sleeve are in contact with each other. When the upper connecting cover plate 10106 and the lower connecting cover plate 10206 swing relative to each other in the circumferential direction, the plane of the front sliding section 1010301 of the upper movable boss 10103 near the lower movable boss 10203 and the guide arc surface 80301 on the upper guide section 803 of the guide wear-resistant sleeve remain in contact and slide relative to each other.

[0048] The curvature of the guide arc surface 80301 is the normal physiological curvature of the human vertebral body. When the lumbar spine bends forward and backward, the upper movable protrusion 10103 slides up and down along the guide arc surface 80301, which plays a guiding role in the lumbar spine curvature after the operation of the patient, thereby reducing the transmitted load force of the lumbar spine.

[0049] The lower end of the intermediate support section 801 of the guide wear-resistant sleeve is fixedly provided with a lower fixing section 802 of the guide wear-resistant sleeve. The lower fixing section 802 of the guide wear-resistant sleeve is located laterally outward from the lower end of the intermediate support section 801 of the guide wear-resistant sleeve. The outermost position of the lower fixing section 802 of the guide wear-resistant sleeve is fixedly provided with a lower fixing boss 80201 of the guide wear-resistant sleeve. The lower fixing boss 80201 of the guide wear-resistant sleeve protrudes upward. The inner surface of the fixing hole 703 of the lower movable boss is laterally fixedly connected to the outer surface of the intermediate support section 801 of the guide wear-resistant sleeve. This can increase the stability of the wear-resistant sleeve 8 and the lower movable boss 10203, and prevent the wear-resistant sleeve 8 and the lower movable boss 10203 from shaking when the upper movable boss 10103 slides up and down along the guide arc surface 80301, which would further affect the accuracy of the guide angle.

[0050] The inner surface of the support limiting hole 602 provides lateral support to the upper movable boss 10103, and the inner surface of the lower movable boss fixing hole 703 provides lateral support to the wear-resistant sleeve 8. The two work together to prevent the upper movable boss 10103 and the lower movable boss 10203 from shaking during movement. This further ensures the accuracy of the guiding position of the upper movable boss 10103 from the guide arc surface 80301 when the upper movable boss 10103 slides up and down along the guide arc surface 80301, greatly reducing the load force transmitted to the lumbar spine.

[0051] The bottom end face of the lower support limiting block 7 is provided with guide wear-resistant sleeve fixing grooves 705 on both sides of the fixing hole 703 of the lower movable boss. The opening direction of the guide wear-resistant sleeve fixing grooves 705 is set downward. The guide wear-resistant sleeve fixing grooves 705 and the lower fixing boss 80201 of the guide wear-resistant sleeve are longitudinally fixedly connected, which can ensure the stability of the connection between the wear-resistant sleeve 8 and the lower support limiting block 7, thereby further ensuring the firmness of the connection between the inner surface of the wear-resistant sleeve 8 and the outer surface of the lower movable boss 10203, and preventing the wear-resistant sleeve 8 from shaking when it moves between the wear-resistant sleeve 8 and the upper movable boss 10103.

[0052] The pedicle screw 4 includes a screw head 401, a screw rod 402 fixedly mounted at the bottom end of the screw head 401, an external thread on the outer circumference of the screw rod 402, a connecting rod fixing groove 404 on the screw head 401, an internal thread 405 on the inner surface of the connecting rod fixing groove 404, a fixing set screw 403 fixedly mounted inside the connecting rod fixing groove 404, an external thread on the outer surface of the fixing set screw 403, and a connection between the external thread on the outer surface of the fixing set screw 403 and the internal thread 405 on the inner surface of the connecting rod fixing groove 404. The upper connecting rod 10101 and the lower connecting rod 10201 are fixedly disposed between the bottom end of the fixing screw 403 and the connecting rod fixing groove 404, respectively. The upper connecting rod 10101 and the lower connecting rod 10201 are longitudinally locked by the thread between the fixing screw 403 and the nail head 401. In use, the screw 402 on the pedicle screw 4 is driven into the interior of the pedicle 302 on the adjacent vertebral body 3, and is fixedly connected with the pedicle 302.

[0053] The thickness of the front sliding section 1010301 on the upper movable boss 10103 is 1.5mm ± 0.3mm, and the thickness of the rear supporting section 1020302 on the lower movable boss 10203 is 3mm ± 0.5mm. This increases the lateral impact resistance of the upper and lower movable bosses 10103 and 10203, greatly reduces the amplitude of their swaying when subjected to lateral thrust, and increases the stability of the upper movable boss 10103 sliding on the lower movable boss 10203. Furthermore, since people often bend forward more than backward in daily life, the thickness of the rear supporting section 1020302 on the lower movable boss 10203 is greater than the thickness of the front sliding section 1010301 on the upper movable boss 10103, further ensuring the stability of the patient during forward bending movements.

[0054] The rear support section 1010302 on the upper movable boss 10103 is provided with a reinforcing support surface 1010303 at one end near the limiting hole 60201 of the lower movable boss. This forms an inverted trapezoidal structure for the rear support section 1010302 on the upper movable boss 10103. The longitudinal tilt angle of the reinforcing support surface 1010303 is 8.5°±0.5°. This angle dimension can strengthen the support surface 1010303 and increase the lateral support force of the upper movable boss 10103, further reducing the swaying amplitude when the lower movable boss 10103 moves.

[0055] The upper connecting rod 10101 and the upper connecting cover plate 10106 are integrally formed structures, as are the lower connecting rod 10201 and the lower connecting cover plate 10206. This can increase the overall torsional strength of the upper connecting component 101 and the lower connecting component 102, and increase the stability of the implant movement. The length of the upper connecting rod 10101 and the lower connecting rod 10201 is 28mm±1mm. The screw cap 401 on the pedicle screw 4 can slide and adjust its position on the upper connecting rod 10101 and the lower connecting rod 10201 to change the positional distance between the pedicle screws 4, thereby adapting to the specifications of different patients' vertebral body physiological curvature.

[0056] The outer diameter of the upper connecting rod 10101 and the lower connecting rod 10201 is 5mm±0.5mm. The included angle between the two upper connecting rods 10101 is 140°±2°, and the included angle between the two lower connecting rods 10201 is 140°±2°. This included angle can meet the usage needs of most adult patients in China with vertebral physiological curvature.

[0057] The angle and gap between the upper connecting rod 10101 and the lower connecting rod 10201 on the same side can be adjusted during processing according to the physiological curvature of different lumbar vertebral segments to ensure that the implant can be applied to lumbar vertebral segments with different physiological curves.

[0058] The upper connecting component 101 and the lower connecting component 102 are made of medical-grade titanium alloy. The elastic protective sleeve 2 and the wear-resistant sleeve 8 are both made of polycarbonate polyurethane (PCU). The limiting band 9 is made of polyether ether ketone (PEEK). Using polycarbonate polyurethane (PCU) material for the wear-resistant sleeve 8 can increase the wear resistance of the wear-resistant sleeve 8, reduce the debris generated during mutual friction, and further ensure that the guiding curvature of the guiding arc surface 80301 on the wear-resistant sleeve 8 still has a stable guiding curvature under long-term friction, thus extending the overall service life of the implant.

[0059] However, the above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. An implant for posterior lumbar spine arthroplasty, characterized in that: An external connection assembly is provided, which includes an upper connection assembly and a lower connection assembly. An upper connection cover plate is provided at the middle position of the upper connection assembly. Upper connection rods are symmetrically fixed on both sides of the upper connection cover plate. An upper clearance groove is provided at the middle position of the top end face on the outer surface of the upper connection cover plate. A longitudinal through hole is provided on the upper connection cover plate. The lower connecting assembly has a lower connecting cover plate in the middle position, and lower connecting rods are symmetrically fixed on both sides of the lower connecting cover plate. The outer surface of the lower connecting cover plate has a lower clearance groove in the middle position of the bottom end face, and the lower connecting cover plate has a longitudinal through hole. The upper connecting rod and the lower connecting rod are equipped with pedicle screws; The outermost position of the bottom end face of the upper connecting cover plate is fixedly provided with an upper fixing groove, the opening of the upper fixing groove is set towards the upper movable boss, and the outermost position of the top end face of the lower connecting cover plate is fixedly provided with a lower fixing groove, the opening of the lower fixing groove is set towards the lower movable boss, and an elastic protective sleeve is fixedly connected between the upper connecting cover plate and the lower connecting cover plate. The elastic protective sleeve has a middle connecting section at its center. This connecting section bends outwards in its free state. An upper fixing section and a lower fixing section are fixed to the upper and lower ends of this connecting section, respectively. An upper fixing boss and a lower fixing boss are fixed to the outermost positions of these two sections, respectively. Both the upper and lower fixing bosses protrude outwards along the circumferential direction. The upper fixing boss and the upper fixing groove are circumferentially fixed together, as are the lower fixing boss and the lower fixing groove. The upper and lower connecting cover plates can swing relative to each other along the circumferential direction, allowing the elastic protective sleeve to undergo elastic deformation. A sealed internal cavity is formed between the bottom end face of the upper connecting cover plate, the top end face of the lower connecting cover plate, and the elastic protective sleeve. An upper movable boss is fixedly provided on the inner side of the bottom end face of the upper connecting cover plate. The upper movable boss is vertically arranged downward relative to the upper connecting cover plate. The upper movable boss has a plate-like structure. The front end of the upper movable boss has a front sliding section, and the rear end of the upper movable boss has a rear support section. A lower movable boss is fixedly provided on the inner side of the top end face of the lower connecting cover plate. The lower movable boss is vertically arranged upward relative to the lower connecting cover plate. The lower movable boss has a plate-like structure. The front end is provided with a front guide section, and one side of the outer surface of the front guide section is provided with a guide arc surface. The rear end of the lower movable boss is provided with a rear support section. One side plane of the front sliding section on the upper movable boss and the guide arc surface on the front guide section on the lower movable boss are in contact with each other. When the upper connecting cover plate and the lower connecting cover plate swing relative to each other in the circumferential direction, one side plane of the front sliding section on the upper movable boss and the guide arc surface on the front guide section on the lower movable boss always maintain contact and slide relative to each other. An upper support limiting block is fixedly provided on the bottom end face of the upper connecting cover plate. The outer circumference of the upper support limiting block and the inner surface of the upper fixed section of the elastic protective sleeve are circumferentially fixedly connected. A longitudinally penetrating support limiting hole is provided on one side of the upper support limiting block. The upper movable boss passes through the support limiting hole. The plane on the side of the rear support section of the upper movable boss away from the guide arc surface on the lower movable boss is laterally fixedly connected to the inner surface on one side of the support limiting hole. A lower movable boss limiting hole is provided between the plane on the side of the rear support section of the upper movable boss close to the guide arc surface on the lower movable boss and the inner surface on the other side of the support limiting hole. The lower movable boss limiting hole is located at the longitudinal extension position of the lower movable boss. A longitudinal threaded hole is provided on the top of the upper support limiting block. The upper support limiting block is locked and fixed by a locking screw passing through the through hole on the upper connecting cover plate and the threaded hole on the upper support limiting block, thus longitudinally locking the upper support limiting block and the upper connecting cover plate. A lower support limiting block is fixedly provided on the top end face of the lower connecting cover plate. The outer circumference of the lower support limiting block and the inner surface of the lower fixed section of the elastic protective sleeve are circumferentially fixedly connected. A longitudinally penetrating lower movable boss fixing hole is provided on one side of the lower support limiting block. The lower movable boss passes through the lower movable boss fixing hole. The outer surface of the rear support section of the lower movable boss and the inner surface of the lower movable boss fixing hole are laterally fixedly connected. An upper movable boss limiting groove is provided at the top of the lower support limiting block at the longitudinal position of the upper movable boss. The upper movable boss limiting groove is located at the longitudinal extension position of the upper movable boss. A longitudinal threaded hole is provided at the bottom of the lower support limiting block. The lower support limiting block is locked and fixed by a locking screw passing through the through hole on the lower connecting cover plate and the threaded hole on the lower support limiting block, thereby longitudinally locking the lower support limiting block and the lower connecting cover plate.

2. The implant for posterior lumbar spine arthroplasty according to claim 1, characterized in that: A limiting band is fixedly provided between the outer circumference of the upper support limiting block at a laterally symmetrical position on the plane of the upper movable boss away from the lower movable boss and the outer circumference of the lower support limiting block at a longitudinally symmetrical position relative to the outer circumference of the upper support limiting block. The limiting band includes a limiting band connecting section, and a limiting band telescopic section is provided at the middle position of the limiting band connecting section. The upper end face of the limiting band connecting section is laterally fixedly connected to the outer circumference of the upper support limiting block, and the lower end face of the limiting band connecting section is laterally fixedly connected to the outer circumference of the lower support limiting block.

3. The implant for posterior lumbar spine arthroplasty according to claim 2, characterized in that: The internal receiving cavity is provided at the position of the bending arc of the middle connecting section, and the limiting band receiving cavity is provided at the position of the bending arc of the middle connecting section. The limiting band extension section bends outward in a free state and is located inside the limiting band receiving cavity.

4. The implant for posterior lumbar spine arthroplasty according to claim 2, characterized in that: The upper and lower ends of the limiting band connecting section are respectively connected and fixedly provided with an upper fixing section and a lower fixing section. The upper fixing section is located between the upper support limiting block and the upper connecting cover plate. The upper connecting cover plate, the upper fixing section of the limiting band and the upper support limiting block are longitudinally fixedly connected. The lower fixing section of the limiting band is located between the lower support limiting block and the lower connecting cover plate. The lower connecting cover plate, the lower fixing section of the limiting band and the lower support limiting block are longitudinally fixedly connected.

5. The implant for posterior lumbar spine arthroplasty according to claim 4, characterized in that: The width of the limiting band is 6mm ± 1mm, and the thickness of the limiting band is 1mm ± 0.2mm.

6. The implant for posterior lumbar spine arthroplasty according to claim 4, characterized in that: The top end face of the upper support limiting block is provided with an upper fixing groove at the position where it is fixedly connected to the upper fixing section of the limiting band. The upper fixing groove, the upper fixing section of the limiting band, and the upper connecting cover plate are longitudinally fixedly connected. The bottom end face of the lower support limiting block is provided with a lower fixing groove at the position where it is fixedly connected to the lower fixing section of the limiting band. The lower fixing groove, the lower fixing section of the limiting band, and the lower connecting cover plate are longitudinally fixedly connected.

7. The implant for posterior lumbar spine arthroplasty according to claim 1, characterized in that: A guide wear-resistant sleeve is fixedly provided on the outer surface of the lower movable boss. A middle support section is provided in the middle of the guide wear-resistant sleeve. An upper guide section is fixedly provided at the upper end of the middle support section. A guide arc surface is provided on one side of the outer surface of the upper guide section. The front sliding section of the upper movable boss, near the lower movable boss, is in contact with the guide arc surface on the upper guide section. When the upper and lower connecting cover plates swing relative to each other in a circumferential direction, the front sliding section of the upper movable boss, near the lower movable boss, and the guide arc surface on the upper guide section remain in contact and slide relative to each other. A guide lower fixing section is fixedly provided at the lower end of the middle support section of the wear-resistant sleeve. The guide lower fixing section is located laterally outward from the lower end of the middle support section of the wear-resistant sleeve. A guide lower fixing boss is fixed at the outermost position of the guide lower fixing section. The guide lower fixing boss protrudes upward. The inner surface of the fixing hole of the lower movable boss is laterally fixedly connected to the outer surface of the middle support section of the wear-resistant sleeve. The bottom end face of the lower support limiting block is provided with guide wear-resistant sleeve fixing grooves on both sides of the fixing hole of the lower movable boss. The opening direction of the guide wear-resistant sleeve fixing grooves is downward. The guide wear-resistant sleeve fixing grooves and the guide lower fixing boss are longitudinally fixedly connected.

8. The implant for posterior lumbar spine arthroplasty according to claim 1, characterized in that: The pedicle screw includes a screw head, a screw rod fixedly mounted at the bottom end of the screw head, an external thread on the outer circumference of the screw rod, a connecting rod fixing groove on the screw head, an internal thread on the inner surface of the connecting rod fixing groove, a fixing set screw fixedly mounted inside the connecting rod fixing groove, an external thread on the outer surface of the fixing set screw, and a threaded connection between the external thread on the outer surface of the fixing set screw and the internal thread on the inner surface of the connecting rod fixing groove. The upper connecting rod and the lower connecting rod are respectively fixed between the fixing set screw and the bottom end of the connecting rod fixing groove. The upper connecting rod and the lower connecting rod are longitudinally locked by the threaded locking between the fixing set screw and the screw head.

9. The implant for posterior lumbar spine arthroplasty according to claim 1, characterized in that: The thickness of the front sliding section on the upper movable boss is 1.5mm ± 0.3mm, and the thickness of the rear support section on the lower movable boss is 3mm ± 0.5mm. The rear end of the upper movable boss is provided with a reinforcing support surface near the limiting hole of the lower movable boss, forming an inverted trapezoidal structure. The longitudinal inclination angle of the reinforcing support surface is 8.5°±0.5°.

10. The implant for posterior lumbar spine arthroplasty according to claim 1, characterized in that: The upper connecting rod and the upper connecting cover plate are integrally formed, and the lower connecting rod and the lower connecting cover plate are integrally formed. The length of the upper connecting rod and the lower connecting rod is 28mm±1mm, the outer diameter of the upper connecting rod and the lower connecting rod is 5mm±0.5mm, the included angle between the two upper connecting rods is 140°±2°, and the included angle between the two lower connecting rods is 140°±2°.

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