Anti-receding expansion type interbody fusion cage and distraction device

Abstract

The interbody fusion cage comprises a tube body and a rod body, the rod body is arranged in the tube body, the rod body is fixed relative to one end of the tube body, a limiting groove is formed in the inner wall of the other end of the tube body, a baffle ring is arranged in the limiting groove, a clamping groove matched with the baffle ring is formed in the rod body, and the baffle ring is arranged in the clamping groove. When the interbody fusion cage is opened, the baffle ring is arranged on the rod body in a sleeving mode, and the baffle ring is arranged in the clamping groove in a clamping mode. According to the interbody fusion cage, the baffle ring is arranged in the limiting groove of the tube body, the clamping groove is formed in the rod body, one end of the rod body and one end of the tube body are relatively fixed, and after the interbody fusion cage is expanded, the baffle ring can be matched with the clamping groove in the rod body to axially limit the fusion cage, so that the fusion cage is in a stable expanded state, and the reliable springback prevention effect is achieved; and the use reliability of the interbody fusion cage is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly relates to an anti-retraction expansion type intervertebral fusion device and a dilator. Background Art

[0002] Due to reasons such as degeneration and injury of the intervertebral disc, the intervertebral space will become smaller, and the nucleus pulposus tissue of the intervertebral disc will protrude from the ruptured annulus fibrosus, compressing surrounding nerves, spinal cord and other structures, forming intervertebral prolapse. The common treatment method for intervertebral prolapse is to implant a fusion device into the intervertebral space. After the intervertebral fusion device is implanted, it can expand the intervertebral space, cooperate with the implantation of autologous or allogeneic bone, restore and maintain the height of the intervertebral space, thereby reducing the compression on surrounding tissues such as nerves and blood vessels, and alleviating symptoms such as pain.

[0003] In order to solve the problems in the prior art that it is difficult to grasp the expansion state of the fusion device for the implanted main body, the expansion sequence of the second expansion sheet cannot be determined, and the second expansion sheet will be in an inclined state, resulting in the skew of the ridge protrusion, the applicant applied for a Chinese utility model patent CN212234811U, which discloses an intervertebral disc fusion device, including a tube body. A plurality of support expansion joints and a stable expansion joint are arranged at intervals in the axial and circumferential directions of the tube body. The support expansion joint includes a support sheet plate. Extension support plates are respectively arranged at both ends of the support sheet plate in the length direction. Both sides of the bottom of the support sheet plate are respectively connected to the tube body through deformation support sheets. An inner bending block for restricting the deformation of the top end of the deformation support sheet is arranged on the support sheet plate. An outer bending block for restricting the deformation of the bottom end of the deformation support sheet is arranged between two adjacent support expansion joints on the tube body. Two relatively arranged limiting blocks are arranged between two support expansion joints in the circumferential direction of the tube body. When the deformation support sheet expands to the maximum, the two limiting blocks abut against each other. This utility model can enable the expansion joints on the tube body to expand from the inside to the outside in sequence and all be in a state with the same expansion size, can ensure that the contact sheets after expansion are in a horizontal state, avoid the skew of the ridge protrusion, can maintain the intervertebral space height and vertebral body stability, and thus will not cause unnecessary harm to patients.

[0004] However, certain deficiencies have been found in the actual use process: after the fusion device is implanted into the human body, under the action of pressure, there is a risk of rebound of the expanded fusion device, and the rebound of the fusion device will cause the collapse of the intervertebral space, recurrence of the patient's symptoms, and even aggravation of the condition in severe cases. Summary of the Invention

[0005] To solve the problems in the background art, avoid the rebound of the fusion device after expansion, and ensure the stable state of the fusion device after implantation, the present invention proposes an anti-retraction expansion type intervertebral fusion device, which includes a tube body and a rod body. The rod body is arranged inside the tube body, one end of the rod body is fixed relative to the tube body, a limiting groove is provided on the inner wall of the other end of the tube body, a retaining ring is arranged in the limiting groove, and a clamping groove matching the retaining ring is provided on the rod body. When the intervertebral fusion device is expanded, the retaining ring is sleeved on the rod body, and the retaining ring is clamped in the clamping groove.

[0006] Preferably, a limiting block is fixed at one end of the rod body, and the radial dimension of the limiting block is larger than the inner diameter of the tube body; A groove for restricting the rotation of the rod body relative to the tube body is provided at the end of the tube body away from the limiting groove. The rod body is inserted into the tube body, and the limiting block is arranged in the groove.

[0007] Preferably, the distance between the end face of the rod body away from the limiting block and the clamping groove is not greater than the distance between the end face of the tube body near the limiting groove and the retaining ring.

[0008] Preferably, an opening is provided on the retaining ring.

[0009] Preferably, when the retaining ring is in a free state, the outer diameter of the retaining ring is smaller than the diameter of the limiting groove, and the outer diameter of the retaining ring is larger than the inner diameter of the tube body, and the inner diameter of the retaining ring is smaller than the inner diameter of the tube body.

[0010] Preferably, the inner diameter of the retaining ring is not greater than the outer diameter of the part of the rod body provided with the clamping groove.

[0011] Preferably, a plurality of support expansion joints and a stable expansion joint are axially arranged on the tube body, and the support expansion joints are arranged on both sides of the stable expansion joint.

[0012] A spreader includes a housing, a handle, an inner push tube and a pull rod. One end of the pull rod is fixed inside the housing, and the other end of the pull rod extends outside the housing. The handle is fixedly connected with a threaded sleeve, the threaded sleeve is rotationally connected with the housing, an inner push tube seat is threadedly connected inside the threaded sleeve, the inner push tube is slidably connected with the housing, the inner push tube is sleeved outside the pull rod, one end of the inner push tube is fixedly connected with the inner push tube seat, and the other end of the inner push tube extends outside the housing. The threaded sleeve is threadedly connected with a sleeve nut, the sleeve nut is fixedly connected with an outer sleeve through a connecting plate, the outer sleeve is sleeved outside the inner push tube, the connecting plate is slidably connected with the housing, the external thread of the threaded sleeve and the internal thread of the threaded sleeve have opposite thread directions, the inner diameter of the outer sleeve is larger than the outer diameter size of the intervertebral fusion device before expansion, and is smaller than the outer diameter size of the intervertebral fusion device after expansion; When the spreader expands the intervertebral fusion device, the end of the pull rod away from the housing is connected to the rod body, and the end of the inner push tube away from the housing is connected to the tube body.

[0013] Preferably, a guiding groove is axially arranged on the inner top pipe seat, the guiding groove radially penetrates through the inner top pipe seat along the radial direction of the inner top pipe seat, a guiding block is slidably arranged in the inner top pipe seat, and both ends of the guiding block extend out of the inner top pipe seat through the guiding groove and are respectively fixedly connected with the inner wall of the shell.

[0014] Preferably, a pointer is fixed on the outer side of the inner top pipe seat, a scale groove is formed at a position corresponding to the pointer on the shell, the pointer is slidably arranged in the scale groove, a scale line is arranged on one side of the scale groove, and the scale line is located on the outer wall of the shell.

[0015] The beneficial effects of the present invention are as follows: In this application, a retaining ring is arranged in the limiting groove of the pipe body, a clamping groove is arranged on the rod body, one end of the rod body is relatively fixed to one end of the pipe body, during the process of expanding the intervertebral fusion device, the end of the rod body provided with the clamping groove moves relative to the pipe body and approaches the retaining ring. When the intervertebral fusion device is expanded, the rod body passes through the inner hole of the retaining ring, and the retaining ring is clamped into the clamping groove on the rod body. The cooperation between the retaining ring and the clamping groove performs axial limitation on the fusion device, preventing the rod body and the pipe body from moving relative to each other again, so that the fusion is in a stable expanded state, playing a reliable role in preventing rebound. At the same time, this application provides a dilator for expanding the fusion device, which can enable the rod body to pass through the retaining ring during the process of expanding the pipe body of the fusion device, ensure the stable progress of the entire expanding process, and ensure that the retaining ring can cooperate with the clamping groove. Description of the Drawings

[0016] Figure 1 is a schematic three-dimensional structure diagram of an anti-retraction expansion type intervertebral fusion device of the present application Figure 1 ; Figure 2 is a schematic three-dimensional structure diagram of an anti-retraction expansion type intervertebral fusion device of the present application Figure 2 ; Figure 3 is a front view of an anti-retraction expansion type intervertebral fusion device of the present application; Figure 4 is Figure 3 the A-A cross-sectional view in Figure 5 is Figure 3 the B-B cross-sectional view in Figure 6 is a schematic three-dimensional structure diagram of an anti-retraction expansion type intervertebral fusion device of the present application in an expanded state; Figure 7 is a schematic diagram of the cooperation relationship between the rod body and the retaining ring of an anti-retraction expansion type intervertebral fusion device of the present application in an expanded state; Figure 8 is a schematic three-dimensional structure diagram of a dilator of the present application; Figure 9Schematic structural diagram of a spreader of the present application without an upper cover; Figure 10 Schematic structural diagram of a spreader of the present application without a housing; Figure 11 Schematic structural diagram of a spreader of the present application without a housing, a connecting plate, and an outer sleeve; Figure 12 is Figure 11 Enlarged structural diagram of part C in Figure 13 is Figure 11 Enlarged structural diagram of part D in In the figure: 1, pipe body; 11, support expansion joint; 12, stable expansion joint; 13, limit groove; 14, abutting groove; 2, rod body; 21, card slot; 22, limit block; 23, through hole; 3, retaining ring; 31, opening; 4, housing; 41, scale groove; 5, handle; 6, threaded sleeve; 7, inner push pipe; 71, abutting block; 8, pull rod; 9, inner push pipe seat; 91, guiding groove; 92, pointer; 93, guiding block; 10, outer sleeve; 101, sleeve nut; 102, connecting plate; 103, sleeve seat; 104, limit baffle. Detailed implementation manners

[0017] In order to make the present invention clearer and more understandable, the technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the given embodiments are only one of the implementation manners and do not represent all embodiments.

[0018] In this article, terms such as "inner" and "outer" are established based on the positional relationship shown in the drawings. Depending on the different drawings, the corresponding positional relationship may also change accordingly. Therefore, it cannot be understood as an absolute limitation of the protection scope.

[0019] Combined with the attached Figure 1 - attached Figure 7 , an anti-retraction expansion type intervertebral fusion device, comprising a pipe body 1 and a rod body 2, the rod body 2 is arranged inside the pipe body 1, one end of the rod body 2 is fixed relative to the pipe body 1, a limit groove 13 is arranged on the inner wall of the other end of the pipe body 1, a retaining ring 3 is arranged in the limit groove 13, an opening 31 is arranged on the retaining ring 3, a card slot 21 matching the retaining ring 3 is arranged on the rod body 2, when the intervertebral fusion device is expanded, the retaining ring 3 is sleeved on the rod body 2, and the retaining ring 3 is clamped in the card slot 21.

[0020] Specifically, a limiting block 22 is fixed at one end of the rod body 2, and the radial dimension of the limiting block 22 is larger than the inner diameter of the tube body 1; a groove for limiting the rotation of the rod body 2 relative to the tube body 1 is provided at one end of the tube body 1 away from the limiting groove 13, and the rod body 2 is inserted into the tube body 1, and the limiting block 22 is arranged in the groove. Through the cooperation of the groove and the limiting block 22, the rod body 2 is fixed relative to one end of the tube body 1, specifically, the end of the rod body 2 provided with the limiting block 22 is fixed relative to the end of the tube body 1 away from the retaining ring 3, and during the process of expanding the intervertebral fusion cage, the end of the rod body 2 provided with the limiting block 22 moves with the end of the tube body 1 away from the retaining ring 3, the tube body 1 gradually shortens, and the end of the rod body 2 away from the limiting block 22 approaches the retaining ring 3. More specifically, the stopper 22 is rectangular, the rod body 2 is located at the center of the stopper 22, the groove matches the shape of the stopper 22, and after the stopper 22 is inserted into the groove, the stopper 22 is restricted by the groove and cannot rotate, and the rod body 2 can be prevented from entering the tube body 1 as a whole. More specifically, when the stopper 22 is located in the groove, the end face of the stopper 22 is parallel to the end face of the tube body 1, and the two radial ends of the stopper 22 are arc surfaces, forming a complete cylindrical surface with the circumferential side of the tube body 1.

[0021] When connecting the rod body 2 and the tube body 1, the end of the rod body 2 away from the limit block 22 is inserted into the tube body 1 from the end of the tube body 1 away from the limit groove 13, and the rod body 2 is pushed along the axial direction of the tube body 1 toward the limit groove 13 until the limit block 22 on the rod body 2 is stuck in the groove of the tube body 1.

[0022] Specifically, the distance between the end face of the rod body 2 away from the limiting block 22 and the clamping groove 21 is not greater than the distance between the end face of the tube body 1 near the limiting groove 13 and the retaining ring 3. It is ensured that when the intervertebral fusion cage is expanded, the end face of the rod body 2 near the limiting groove 13 is located inside the tube body 1, or is flush with the end face of the tube body 1 near the limiting groove 13, so as to avoid the rod body 2 extending outside the tube body 1 and increasing the ineffective size of the fusion cage after expansion.

[0023] Specifically, when the retaining ring 3 is in a free state, the outer diameter of the retaining ring 3 is smaller than the diameter of the limiting groove 13, and the outer diameter of the retaining ring 3 is larger than the inner diameter of the tube body 1, and the inner diameter of the retaining ring 3 is smaller than the inner diameter of the tube body 1. It is ensured that the retaining ring 3 can be in the limiting groove 13, and there is space for the retaining ring 3 to expand.

[0024] Specifically, the inner diameter of the retaining ring 3 is not greater than the outer diameter of the portion of the rod body 2 provided with the slot 21. When the retaining ring 3 is inserted into the slot 21, the retaining ring 3 can hold the rod body 2 tightly, thereby forming a whole with the rod body 2 and improving the connection effect.

[0025] Specifically, a plurality of support expansion joints 11 and a stable expansion joint 12 are axially arranged on the pipe body 1, and the support expansion joints 11 are provided on both sides of the stable expansion joint 12. More specifically, two support expansion joints 11, a stable expansion joint 12 and a support expansion joint 11 are successively arranged on the pipe body 1 along the axial direction.

[0026] Specifically, the end of the rod body 2 away from the limit block 22 is in a conical or spherical structure, and the clamping groove 21 is located on the side of the conical or spherical structure close to the limit block 22; when it is in a conical structure, the conical end of the conical structure is located at the end of the rod body 2 away from the limit block 22. During the process of expanding the intervertebral fusion device, the conical or spherical structure at the end of the rod body 2 can play a guiding role, facilitating the rod body 2 to pass through the inner hole of the retaining ring 3 more accurately and stably.

[0027] Combined with the attached Figure 8 - attached Figure 13 A spreader, comprising a housing 4, a handle 5, an inner push pipe 7 and a pull rod 8. One end of the pull rod 8 is fixed inside the housing 4, and the other end of the pull rod 8 extends outside the housing 4. The handle 5 is fixedly connected with a threaded sleeve 6. The threaded sleeve 6 is rotatably connected with the housing 4. An inner push pipe seat 9 is threadedly connected inside the threaded sleeve 6. The inner push pipe 7 is slidably connected with the housing 4. The inner push pipe 7 is sleeved outside the pull rod 8. One end of the inner push pipe 7 is fixedly connected with the inner push pipe seat 9, and the other end of the inner push pipe 7 extends outside the housing 4. The threaded sleeve 6 is threadedly connected with a sleeve nut 101. The sleeve nut 101 is fixedly connected with an outer sleeve pipe 10 through a connecting plate 102. The outer sleeve pipe 10 is sleeved outside the inner push pipe 7. The connecting plate 102 is slidably connected with the housing 4. The external thread of the threaded sleeve 6 and the internal thread of the threaded sleeve 6 have opposite thread directions; When the spreader expands the intervertebral fusion device, the end of the pull rod 8 away from the housing 4 is connected to the rod body 2, and the end of the inner push pipe 7 away from the housing 4 is connected to the pipe body 1.

[0028] Specifically, the end of the pull rod 8 away from the housing 4 is provided with an external thread. The rod body 2 is tubular, that is, a through hole 23 is arranged inside the rod body 2 along the length direction of the rod body 2. The inner wall of the through hole 23 at one end of the rod body 2 close to the limit groove 13 is provided with an internal thread; one end of the pipe body 1 close to the retaining ring 3 is provided with a butting groove 14, and the end of the inner push pipe 7 away from the housing 4 is provided with a butting block 71 matching with the butting groove 14. When the spreader expands the intervertebral fusion device, the pull rod 8 is connected to the rod body 2 through the cooperation of the external thread and the internal thread, and the butting block 71 is inserted into the butting groove 14.

[0029] Specifically, there are two connecting plates 102. The two connecting plates 102 are symmetrically distributed on both sides of the inner pipe socket 9. One end of each of the two connecting plates 102 is fixedly connected to the sleeve nut 101, and a sleeve seat 103 is fixedly connected between the other ends of the two connecting plates 102. One end of the outer sleeve 10 is fixedly connected to the sleeve seat 103, and the other end of the outer sleeve 10 extends outside the housing 4. Limiting baffles 104 are respectively arranged on both sides of the two connecting plates 102, and the limiting baffles 104 are fixedly connected to the housing 4. When the threaded sleeve 6 rotates, the connecting plate 102 is limited by the limiting baffle 104 and cannot rotate, so that the sleeve nut 101 connected thereto cannot rotate. Furthermore, the sleeve nut 101 moves axially along the threaded barrel 6 under the thread action of the threaded barrel 6, and the sleeve nut 101 drives the outer sleeve 10 to move radially through the connecting plate 102.

[0030] The inner diameter of the outer sleeve 10 is larger than the outer diameter of the intervertebral fusion device before it is expanded and smaller than the outer diameter of the intervertebral fusion device when it is expanded.

[0031] Before the dilator expands the intervertebral fusion device, one end of the pull rod 8 far from the housing 4 is connected to the rod body 2, one end of the inner pipe 7 far from the housing 4 is connected to the pipe body 1, and the entire intervertebral fusion device is located inside the outer sleeve 10. When expanding, rotate the handle 5, and the handle 5 drives the threaded sleeve 6 to rotate. At this time, the inner pipe socket 9 moves under the thread action, driving the end of the inner pipe 7 connected to the intervertebral fusion device to extend outside the housing 4. Since the pull rod 8 is fixed to the housing 4, relative movement will occur between the inner pipe 7 and the pull rod 8 when the inner pipe 7 moves, and the end of the inner pipe 7 far from the housing 4 and the end of the pull rod 8 far from the housing 4 gradually approach. At the same time, since the external thread of the threaded sleeve 6 and the internal thread of the threaded sleeve 6 have opposite thread directions, the inner pipe 7 and the outer sleeve 10 move in opposite directions, and the intervertebral fusion device gradually moves outside the outer sleeve 10.

[0032] As the ends of the inner pipe 7 and the pull rod 8 approach, the pipe body 1 of the intervertebral fusion device will be expanded, the length of the pipe body 1 gradually shortens, and the end of the rod body 2 close to the limiting groove 13 continuously approaches the retaining ring 3, and the intervertebral fusion device gradually moves outside the outer sleeve 10. Since the intervertebral fusion device is located inside the outer sleeve 10 in the initial state, the part of the intervertebral fusion device inside the outer sleeve 10 is restricted by the outer sleeve 10 and cannot expand. Only the part that moves outside the outer sleeve 10 can be expanded. Therefore, through the limiting action of the outer sleeve 10, step-by-step expansion of the intervertebral fusion device can be realized, that is, one expansion stage is when one expansion joint is expanded. After the intervertebral fusion device is fully expanded, the rod body 2 passes through the retaining ring 3, and the retaining ring 3 is clamped in the card slot 21, and the rotation of the handle 5 is stopped.

[0033] When the spreader needs to be removed, only the handle 5 needs to be rotated in the reverse direction, so that the end of the inner top pipe 7 in contact with the pipe body 1 contracts into the housing 4, and the top contact block 71 will disengage from the top contact groove 14. Then, rotate the housing 4, drive the pull rod 8 to rotate through the housing 4, and screw the pull rod 8 out of the rod body 2.

[0034] Specifically, a guide groove 91 is axially provided on the inner top pipe seat 9, the guide groove 91 penetrates the inner top pipe seat 9 along the radial direction of the inner top pipe seat 9, a guide block 93 is slidably arranged in the inner top pipe seat 9, and both ends of the guide block 93 extend out of the inner top pipe seat 9 through the guide groove 91 and are respectively fixedly connected to the inner wall of the housing 4. The cooperation between the guide block 93 and the guide groove 91 can limit the rotation of the inner top pipe 7. Furthermore, when the threaded sleeve 6 rotates, the inner top pipe seat 9 cannot rotate with the threaded sleeve 6 but moves along its own axial direction.

[0035] Specifically, a pointer 92 is fixedly arranged on the outer side of the inner top pipe seat 9, a scale groove 41 is formed at a position corresponding to the pointer 92 on the housing 4, the pointer 92 is slidably arranged in the scale groove 41, a scale line is arranged on one side of the scale groove 41, and the scale line is located on the outer wall of the housing 4. The pointer 92 can move with the inner top pipe seat 9. Cooperating with the scale line, it plays a role in indicating the moving distance. The user can judge the moving distance of the inner top pipe 7 through the scale value at the position where the pointer 92 moves, and further can judge the spreading condition of the intervertebral fusion device.

[0036] More specifically, the housing 4 includes an upper cover and a lower cover, the upper cover and the lower cover are assembled to form the housing 4, both the upper cover and the lower cover are provided with a scale groove 41 and scale values, there are two pointers 92, the two pointers 92 are located on the same diameter direction of the inner top pipe seat 9, and the two pointers 92 are respectively located in the scale grooves 41 of the upper cover and the lower cover.

[0037] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An anti-recession expandable intervertebral fusion cage, characterized in that: The invention comprises a tube body (1) and a rod body (2), wherein the rod body (2) is arranged in the tube body (1), the rod body (2) is fixed relative to one end of the tube body (1), a limiting groove (13) is provided on the inner wall of the other end of the tube body (1), a retaining ring (3) is provided in the limiting groove (13), and a clamping groove (21) matching the retaining ring (3) is provided on the rod body (2), and when the intervertebral fusion device is expanded, the retaining ring (3) is sleeved on the rod body (2), and the retaining ring (3) is clamped in the clamping groove (21).

2. The anti-retrogression expandable intervertebral fusion cage according to claim 1, characterized in that: A limiting block (22) is fixed at one end of the rod body (2), and the radial dimension of the limiting block (22) is greater than the inner diameter of the tube body (1); A groove for limiting the rotation of the rod body (2) relative to the tube body (1) is provided at one end of the tube body (1) away from the limiting groove (13); the rod body (2) is inserted into the tube body (1), and the limiting block (22) is located in the groove.

3. The anti-recession expandable intervertebral fusion cage according to claim 1, characterized in that: The distance between the end surface of the rod body (2) away from the limiting block (22) and the clamping groove (21) is not greater than the distance between the end surface of the tube body (1) close to the limiting groove (13) and the retaining ring (3).

4. The anti-recession expandable intervertebral fusion cage according to claim 1, characterized in that: The retaining ring (3) is provided with an opening (31).

5. The anti-recession expandable intervertebral fusion cage according to claim 4, characterized in that: When the retaining ring (3) is in a free state, the outer diameter of the retaining ring (3) is smaller than the diameter of the limiting groove (13), the outer diameter of the retaining ring (3) is larger than the inner diameter of the tube body (1), and the inner diameter of the retaining ring (3) is smaller than the inner diameter of the tube body (1).

6. The anti-retrogression expandable intervertebral fusion cage according to claim 5, characterized in that: The inner diameter of the retaining ring (3) is no greater than the outer diameter of the portion of the rod body (2) where the clamping groove (21) is provided.

7. The anti-recession expandable intervertebral fusion cage according to claim 1, characterized in that: A plurality of supporting expansion joints (11) and a stabilizing expansion joint (12) are axially arranged on the tube body (1), and both sides of the stabilizing expansion joint (12) are provided with the supporting expansion joints (11).

8. A distractor, applied to the anti-recession expandable intervertebral fusion cage according to any one of claims 1 to 7, characterized in that: The invention comprises a shell (4), a handle (5), an inner jacking tube (7) and a pull rod (8), wherein one end of the pull rod (8) is fixed inside the shell (4), and the other end of the pull rod (8) extends outside the shell (4); the handle (5) is fixedly connected to a threaded sleeve (6), and the threaded sleeve (6) is rotatably connected to the shell (4); the inner thread of the threaded sleeve (6) is connected to an inner jacking tube seat (9); the inner jacking tube (7) is slidably connected to the shell (4); the inner jacking tube (7) is sleeved outside the pull rod (8), and one end of the inner jacking tube (7) is fixedly connected to the inner jacking tube seat (9); (7) the other end extends to the outside of the shell (4), the threaded sleeve (6) is externally threadedly connected to a sleeve nut (101), the sleeve nut (101) is fixedly connected to an outer sleeve (10) via a connecting plate (102), the outer sleeve (10) is sleeved outside the inner top tube (7), the connecting plate (102) is slidably connected to the shell (4), the threaded sleeve (6) has an external thread in the opposite direction to the internal thread of the threaded sleeve (6), and the inner diameter of the outer sleeve (10) is larger than the outer diameter of the intervertebral fusion device when it is not expanded, and smaller than the outer diameter of the intervertebral fusion device when it is expanded; When the expander expands the intervertebral fusion cage, the end of the pull rod (8) away from the shell (4) is connected to the rod body (2), and the end of the inner top tube (7) away from the shell (4) is connected to the tube body (1).

9. A spreader according to claim 8, characterized in that: A guide groove (91) is axially provided on the inner top tube seat (9), the guide groove (91) radially penetrates the inner top tube seat (9), a guide block (93) is slidably provided inside the inner top tube seat (9), and two ends of the guide block (93) extend out of the inner top tube seat (9) through the guide groove (91) and are respectively fixedly connected to the inner wall of the shell (4).

10. A spreader according to claim 8, characterized in that: A pointer (92) is fixed on the outside of the inner top tube seat (9); a scale groove (41) is provided on the housing (4) at a position corresponding to the pointer (92); the pointer (92) is slidably arranged in the scale groove (41); scale lines are provided on one side of the scale groove (41); and the scale lines are located on the outer wall of the housing (4).

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