Interbody fusion device

Abstract

This invention relates to a prosthesis for implantation into the intervertebral space of the cervical spine. Specifically, this invention discloses an intervertebral fusion device, comprising: a fusion body having two end faces and a bone graft window penetrating the two end faces, the fusion body being implanted into the intervertebral space with its two end faces facing the endplates of the two vertebrae respectively; a bone plate having through holes located at the upper and lower parts respectively, the bone plate being arranged on the anterior side of the cervical spine and spanning the two vertebrae defining the intervertebral space, the upper and lower through holes being opposite to the two vertebrae respectively; bone screws, which are screwed into the vertebrae through the upper and lower through holes of the bone plate to fix the bone plate to the two vertebrae respectively; and a linear component having a proximal end and a distal end, the proximal end of the linear component being attached to the middle part of the bone plate, and the distal end of the linear component extending into the intervertebral space and attached to the anterior side of the fusion body to limit the displacement of the fusion body and maintain the fusion body in the middle region of the intervertebral space.

Description

Technical Field

[0001] This invention relates to a prosthesis for implantation in the intervertebral space of the human cervical spine, and more particularly to an intervertebral fusion device. Background Technology

[0002] Anterior cervical discectomy and fusion (ACDF) is a surgical procedure in which the intervertebral disc is removed from the anterior cervical spine and a fusion device (or intervertebral implant) is inserted. After the fusion device is implanted, the endplate of the vertebra, after the surface cartilage has been scraped off, grows new bone in the direction of the opposite vertebra and combines with the fusion device to eventually fill the entire intervertebral space, thereby achieving fusion and fixation of the upper and lower vertebrae.

[0003] After the fusion cage is implanted into the intervertebral space, it is necessary to fix the two vertebrae above and below the fusion cage. The purpose of fixing the two vertebrae is twofold: firstly, to prevent the fusion cage from shifting or even dislodging from the intervertebral space in the early postoperative period before the two vertebrae fuse due to the enlargement of the intervertebral space; secondly, by fixing the two vertebrae and pressing them against the end face of the fusion cage with a certain pressure, the fusion cage can stimulate the endplate of the vertebrae, thereby promoting the growth of new bone towards the fusion cage in the area opposite to the fusion cage.

[0004] Based on the different methods of vertebral fixation, two types of interbody fusion devices are provided in the prior art.

[0005] The first type of interbody fusion device.

[0006] like Figure 1 As shown, the intervertebral fusion device 200 includes: a fusion body 201 and a bone screw 202, and a through hole extending obliquely from the front side of the fusion body 201 and penetrating the upper and lower end faces of the fusion body. During the surgery, the fusion device body 201 is implanted into the intervertebral space 1001, which has been retracted by a retractor and the endplate cartilage has been scraped away. Then, the bone screw 202 passes through a through hole on the front side of the fusion device body 201 and exits through the end face of the fusion device body 201. By turning the bone screw 202, its head is tilted and screwed into the vertebra 1000 through the endplate. By tightening the bone screw 202, the endplate of the vertebra 1000 is pressed against the end face of the fusion device body 201. In this way, the two vertebrae 1000 are fixed by the bone screws 202 that pass through the upper and lower end faces of the fusion device body 201 respectively and by means of the fusion device body 201 (this type of intervertebral fusion device has been disclosed in Chinese patents such as CN108852563A anterior cervical intervertebral fusion device with zero notch and CN118453212A an anti-regression trabecular zero notch intervertebral fusion device).

[0007] The second type of interbody fusion device.

[0008] like Figure 2 As shown, the vertebral fusion device 200' includes: a fusion body 201', a bone plate 203', and bone screws 202'; the upper and lower parts of the bone plate 203' are provided with through holes, and the bone screws 202' are used to pass through the through holes. During the operation, firstly, the fusion body 201' is inserted into the intervertebral space 1001, which has been retracted by a retractor and the endplate cartilage has been scraped away. Then, the bone plate 203' is placed on the anterior side of the vertebra 1000 and spans two vertebrae 1000 simultaneously. Thus, the upper and lower through holes of the bone plate 203' are opposite to the anterior surfaces of the upper and lower vertebrae, respectively. Then, the bone screws 202' are passed through the upper and lower through holes respectively, and the heads of the bone screws 202' are laterally screwed into the vertebra 1000 through the surface of the vertebra 1000 by turning the bone screws 202'.

[0009] The significant difference between the second type of interbody fusion device and the first type is that in the first type of interbody fusion device, the bone screws, the fusion device body, and the vertebrae are connected to each other, while in the second type of interbody fusion device, the fusion device body and the bone plate are separate, and the fusion device and the vertebrae are not connected.

[0010] The advantages and disadvantages of the two types of interbody fusion devices mentioned above will be introduced below.

[0011] Advantages and disadvantages of the first type of vertebral fusion device.

[0012] Advantages: The bone screws, the fusion device body, and the vertebra are connected to each other. Therefore, once the fusion device body is fixed during the operation, it will not shift after the operation. In addition, the entire device is located in the area where the intervertebral space is located and does not protrude from the anterior surface of the vertebra, thereby avoiding affecting anterior cervical tissues such as the esophagus and trachea. Therefore, this device is usually called a zero-notch intervertebral fusion device.

[0013] Disadvantages: During surgery, because the bone screw is inserted into the vertebrae at an angle through the endplate, the screw head may slip and shift during screw tightening, leading to undesirable displacement of the fusion cage. Also, the angle at which the bone screw is screwed into the vertebra may deviate from the predetermined angle, causing undesirable changes in the posture of the fusion cage. This results in different contact pressures on different areas of the end face of the fusion cage, or even only a localized area of ​​the end face contacting the endplate, for example... Figure 2As shown, only the anterior side of the end face contacts the endplate, while the posterior side does not. Because the endplate area opposite the non-contact area of ​​the fusion device body's end face cannot be stimulated by the fusion device body, new bone growth in the surrounding area is slower. Overcoming these two defects requires the surgeon's experience and skill. Furthermore, since new bone grows from the endplate, bone screws inserted into the vertebra through the endplate can damage bone tissue near the endplate, thus affecting new bone growth; additionally, repair surgery is difficult after bone screws slip.

[0014] Advantages and disadvantages of the second type of interbody fusion device.

[0015] Advantages: Because the bone screws are used to fix the bone plate and are separate from the fusion cage body, the posture of the fusion cage body is less affected by the bone plate during surgery, resulting in better fit between the end face of the fusion cage body and the vertebra. Since the bone screws are inserted transversely into the vertebra from the anterior side, the insertion area is farther from the bone tissue near the endplate, thus having less impact on new bone growth. Furthermore, because the bone screws are inserted transversely from the anterior side of the vertebra, the intraoperative fixation of the vertebra is simple.

[0016] shortcoming:

[0017] 1. Because the fusion cage body is not fixed to the vertebrae during the operation, the fusion cage body may shift in the early stage of the operation and before the two vertebrae are fused. If the fusion cage body shifts to the posterior side, it may cause the fusion cage body to protrude from the posterior side of the vertebra and compress the spinal cord. Although the probability of this is not high, once the spinal cord is compressed, it may have serious consequences (such as high paraplegia).

[0018] 2. Since the bone plate is not an absolutely rigid component, and the bending stiffness of the bone plate in the sagittal plane is much smaller than that in the coronal plane, in the early postoperative period, if the patient's neck makes a large range of flexion and extension movements, resulting in frequent increases in the distance between the posterior sides of the vertebrae and decreases in the distance between the anterior sides, the fusion cage body may be squeezed and moved posteriorly, thereby increasing the probability that the fusion cage body protrudes from the posterior side of the vertebrae.

[0019] 3. To reduce the probability of the fusion cage protruding posteriorly from the vertebra, during surgery, the fusion cage is usually positioned anterior to the intervertebral space, or even flush with the anterior side of the vertebra, to increase the distance between the posterior side of the fusion cage and the posterior side of the vertebra. This can reduce the probability of protrusion posteriorly from the vertebra and compressing the spinal cord to some extent. However, this leads to the following result: the amount of new bone on the anterior periphery of the fusion cage is much smaller than that on the posterior side and the left and right sides (the so-called periphery new bone refers to new bone that grows from the endplate without being directly stimulated by the end face of the fusion cage and is located outside the area corresponding to the end face of the fusion cage; the growth rate of this new bone lags behind the growth rate of new bone in the area corresponding to the end face of the fusion cage, e.g. If the growth rate of new bone in the area corresponding to the bone graft window lags behind, the fusion cage may not be located in the middle of the surrounding new bone. In some cases, the front side of the fusion cage may not be covered by surrounding new bone because it is flush with the front side of the vertebra. This state has a large difference in mechanical properties from the ideal state where the intervertebral space is completely filled with new bone (while if the fusion cage is located in the middle area, the difference from the ideal state where it is completely filled with new bone is not significant). This can lead to the following: if the bone plate needs to be removed after intervertebral fusion due to the impact on anterior cervical tissues such as the esophagus and trachea, the two fused vertebrae may have insufficient bending resistance in the sagittal plane to flexion-flexion movements (flexion-flexion movements include flexion-flexion movements and flexion-flexion movements) after the bone plate is removed.

[0020] 4. The bone plates have high tensile stiffness in the direction of their arrangement along the vertebrae. Therefore, in this direction, the bone plates can be considered rigid bodies. Postoperatively, because the bone plates cannot elongate, the growth of new bone can lead to excessive contact pressure between the endplate and the end face of the fusion cage. Excessive contact pressure can actually hinder new bone growth. Furthermore, for patients with osteoporosis, excessive contact pressure may even cause collapse of the bone tissue inside the vertebra. Although bone plates capable of elastic elongation have been developed in the present technology, configuring elastic elongation functionality results in complex bone plate structures and increased processing difficulty.

[0021] 5. The anterior surface of the vertebra is not an ideal smooth cylindrical surface and may be uneven, especially in middle-aged and elderly patients. In addition, the bone plate is relatively hard, and the large pre-tightening force between the bone plate and the anterior surface of the vertebra may damage the bone tissue in the local protruding areas of the anterior surface.

[0022] 6. During the surgery, because the patient is in a supine position, after the fusion device is implanted into the intervertebral space, it is necessary to use clamping tools to keep the two vertebrae in a compressed state while installing the bone plate. Because the operating space is occupied by the clamping tools, the installation of the bone plate becomes more difficult. Summary of the Invention

[0023] To address the aforementioned technical problems in the prior art, the present invention provides an intervertebral fusion device.

[0024] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0025] An interbody fusion device, comprising:

[0026] The fusion device body has two end faces, each configured with multiple tips, and a bone graft window penetrating the two end faces. The fusion device body is implanted into the intervertebral space with its two end faces facing the endplates of the two vertebrae respectively.

[0027] A bone plate having through holes located at the upper and lower parts, the bone plate being arranged on the anterior side of the cervical vertebrae and spanning two vertebrae that define the intervertebral space, the upper through hole and the lower through hole being opposite to the two vertebrae respectively;

[0028] Bone screws are inserted into the vertebrae through through holes in the upper and lower parts of the bone plate to fix the bone plate to the two vertebrae respectively.

[0029] A linear component having a proximal end and a distal end, the proximal end of the linear component being attached to the middle of the bone plate, and the distal end of the linear component extending into the intervertebral space and attached to the anterior side of the fusion body to restrict displacement of the fusion body and maintain the fusion body in the middle region of the intervertebral space.

[0030] Preferably, the distal end of the linear component is attached to the front side of the fusion body in a manner that allows the fusion body to oscillate in all directions and locks the fusion body after oscillation.

[0031] Preferably, the linear component includes:

[0032] The tube has a bone plate inserted through its proximal end and exposed on the front side of the bone plate, and has a countersunk hole. The distal end of the tube has an expandable part surrounded by multiple expandable bodies. The front side of the fusion device body has an inlet and an outlet and a spherical cavity located behind the inlet. The expandable part is used to extend into the spherical cavity through the inlet.

[0033] A rod body, which passes through the tube hole of the tube body, has a screw at the proximal end of the rod body and a tapered end at the distal end of the rod body. By driving the rod body forward and cooperating with the expansion body of the expandable part through the tapered end, the expansion body is forced to expand into a spherical shape to tighten the spherical cavity and lock the fusion device body and the distal end of the tube body.

[0034] A drive nut is fitted onto the screw of the rod and located in a countersunk hole at the proximal end of the tube, so that a force-applying tool can be inserted from the front side of the bone plate into the countersunk hole of the tube and act on the drive screw to drive the rod forward by tightening the nut.

[0035] Preferably, the outer peripheral surface of the segment of the tube located in the intervertebral space is a conical cylindrical surface with a diameter at the distal end smaller than that at the proximal end, and after the expandable part contracts due to the elastic reset of the expandable body, the radial dimension of the expandable part is smaller than the radial dimension of the inlet and smaller than the radial dimension of the distal end of the conical cylindrical surface of the tube.

[0036] Preferably, a groove is formed from the front side of the bone plate, and a central hole penetrating the bone plate is formed at the bottom of the groove, with the proximal end of the tube passing through the central hole;

[0037] An elastic connecting component is provided in the settling tank. The elastic connecting component has a flange ring and a sleeve integrally formed with the flange ring. The flange ring is attached and fixed to the settling tank. The sleeve passes through the proximal end of the pipe. A notch is opened on the sleeve wall to divide the sleeve wall into circumferentially arranged clamping walls. External threads are provided on the section where the notch is located. A locking nut is fitted on the sleeve. By tightening the locking nut, the clamping walls can clamp or release the pipe. Wherein:

[0038] The junction area between the flange ring and the sleeve is configured with a corrugated wall, which allows the sleeve to move by elastic deformation.

[0039] Preferably, the bone plate includes a main plate and two sub-plates that cooperate with the main plate, and the through holes in the upper and lower parts of the bone plate are respectively arranged on the two sub-plates; wherein:

[0040] This allows each sub-plate to move elastically in the up and down directions relative to the main plate.

[0041] Preferably, the main board has two slots, which extend vertically from the upper and lower end faces of the main board, respectively; the sub-board has an attachment plate portion and an insertion plate portion integrally formed with the attachment plate portion, and the insertion plate portions of the two sub-boards are inserted into the two slots from the top and bottom of the main board, respectively, and can move along the slots; wherein:

[0042] A tongue is cut out in the middle region of the plug plate, with the head of the tongue facing the attachment plate. Elastic strips are cut on the tongue to allow it to deform elastically. A positioning hole is provided at the head of the tongue.

[0043] A pin hole is provided in the area opposite to the positioning hole of the main board body. A pin is installed in the pin hole. The pin passes through the positioning hole, so that when the sub-plate body moves away from the main board body, the pin limits the head of the tongue, causing the elastic strip to deform elastically and allowing the sub-plate body to move elastically.

[0044] Preferably, the positioning hole is configured as an elongated hole with a dimension in the length direction of the tongue that is larger than its dimension in the width direction of the tongue plate;

[0045] A threaded hole is provided at the end of the pin, and a radial hole is provided on the pin that passes through the threaded hole. The radial hole faces the wall of the positioning hole in the insertion direction of the plug plate. A top ball is provided in the radial hole, and a tightening pin with a conical head is screwed into the threaded hole. By screwing the tightening pin, the conical head pushes the top ball radially outward to push against the wall of the positioning hole.

[0046] Preferably, a spacer is provided at the inner end of the through hole, the spacer having a sleeve-shaped main body and a plurality of finger-shaped elastic strips integrally formed with the sleeve-shaped main body and arranged circumferentially to form a trumpet shape; an insertion hole is opened at the inner end of the through hole, the sleeve-shaped main body is inserted into the insertion hole, and the bone screw passes through the sleeve-shaped main body; wherein:

[0047] When the head of the bone screw is screwed into the vertebra and tightened, the finger-shaped elastic strip deforms to fit and press against the anterior surface of the vertebra.

[0048] Preferably, a clearance groove is provided on the rear side of the spherical cavity of the fusion body, the clearance groove being used to accommodate the tapered end of the distal end of the rod of the linear component.

[0049] Preferably, the fusion device body is made of polyetheretherketone material; the cross-section of the bone graft window of the fusion device body is rectangular; the size of the window of the bone graft window is larger than the size of the central area of ​​the bone graft window; the apex is a plurality of rectangularly arranged quadrangular pyramids.

[0050] Preferably, the bone plate is made of titanium alloy, and both the tube and rod of the linear component are made of titanium alloy. The tube is made of two different titanium alloys. The titanium alloys used to make the bone plate and rod include Ti-6Al-4V. The titanium alloys used to make the tube include Ti-6Al-4V, and any one of Ti-13Nb-13Zr and Ti-12Mo-6Zr-2Fe.

[0051] Compared with the prior art, the beneficial effects of the interbody fusion device disclosed in this invention are:

[0052] 1. In this invention, by adding a linear component and attaching both ends of the linear component to the bone plate and the fusion device body respectively, a connection relationship is established between the bone plate and the fusion device body. This restricts the displacement of the fusion device body in the early postoperative period before the two vertebrae have fused, thereby preventing the fusion device body from protruding from the posterior side of the vertebrae and compressing the spinal cord.

[0053] 2. Because the bone plate can restrict the posterior movement of the fusion cage body through linear components, the fusion cage body can be placed in the approximate middle area of ​​the intervertebral space instead of the anterior area. This makes the peripheral space around the fusion cage body for new bone growth more uniform and consistent. After the peripheral new bone finally fills the peripheral space and fusion is achieved, the fusion cage body is uniformly covered by the peripheral new bone.

[0054] 3. Because the linear component is a slender component with a large length-to-diameter ratio, the volume ratio of the peripheral space occupied by the segment of the linear component in the intervertebral space for the growth of new bone is very small. The linear component has almost no impact on the bone fusion of the peripheral space and the mechanical properties after fusion.

[0055] 4. After the fusion of two vertebrae, if discomfort is caused by the bone plate affecting the anterior cervical tissues such as the trachea and esophagus, and it is necessary to remove the bone plate and linear component, the linear component can be easily dislodged from the fused peripheral bone because the outer periphery of the segment of the intervertebral space of the tube is a cone-cylindrical surface and the radial dimension of the repositioned expandable part is smaller than the radial dimension of the distal end of the cone-cylindrical surface, leaving only a small bone hole.

[0056] 5. Since the fusion unit body is attached to the far end of the linear component in a omnidirectional swing manner, the swing center of the fusion unit body is located on the physical body of the fusion unit body. Therefore, adjusting the attitude of the fusion unit body will not cause displacement of the fusion unit body, making the position adjustment and attitude adjustment almost independent of each other.

[0057] 6. During ACDF, the operation of switching the attachment state of the distal end of the linear component to the fusion device body is performed on the outside of the bone plate, thus simplifying the procedure; when removal of the bone plate and linear component is required, all removal operations are performed on the outside of the bone plate, thus simplifying the removal operation.

[0058] 7. During bone fusion after ACDF surgery, new bone growth and fusion may cause relative positional changes between the fusion device body and the bone plate. By forming a semi-locked connection between the fusion device body and the distal end of the linear component, and by forming a swinging connection between the linear component and the bone plate with the help of elastic connecting components, the linear component is allowed to swing slightly to adapt to the relative positional changes between the fusion device body and the bone plate. This avoids the linear component pulling the fusion device body relative to the vertebra and causing displacement and posture changes due to the relative positional changes between the fusion device body and the bone plate.

[0059] 8. By configuring the bone plate to be elastically elongated, the contact pressure between the endplate of the vertebra and the end face of the fusion device body can be suppressed within a reasonable range to accommodate new bone growth. Furthermore, the present invention obtains a tongue plate with elastic properties from the bone plate through cutting, and then configures the bone plate to achieve elastic elongation, which makes the bone plate simple in structure, easy to manufacture, and easy to assemble.

[0060] 9. By configuring the bone plate with clamping pins, top beads and elongated holes and other related structures to apply pre-tightening force to the two vertebrae, the use of clamping tools to apply pre-tightening force to the two vertebrae is avoided, thus simplifying the installation operation of the bone plate.

[0061] 10. By setting spacer components with multiple finger-shaped elastic strips at the corresponding differences in the through holes, after the vertebrae are fixed with bone screws, the multiple finger-shaped elastic strips disperse the contact force between the spacer components and the anterior surface of the vertebrae, thus avoiding stress concentration in this area. Attached Figure Description

[0062] Figure 1 A state view of the first type of intervertebral fusion device in the prior art after implantation into the intervertebral space.

[0063] Figure 2 A state view of the second type of intervertebral fusion device in the prior art after implantation into the intervertebral space.

[0064] Figure 3 This is a three-dimensional structural diagram of the intervertebral fusion device provided in an embodiment of the present invention.

[0065] Figure 4 This is a three-dimensional sectional view of the intervertebral fusion device provided in an embodiment of the present invention.

[0066] Figure 5 A perspective sectional view of the fusion device body provided for an embodiment of the present invention.

[0067] Figure 6 This is a three-dimensional structural diagram of the linear component in the intervertebral fusion device provided in an embodiment of the present invention.

[0068] Figure 7 This is a three-dimensional structural diagram of the main body in the bone plate provided in an embodiment of the present invention.

[0069] Figure 8 This is a three-dimensional structural diagram of the sub-plate in the bone plate provided in an embodiment of the present invention.

[0070] Figure 9 This is a three-dimensional structural diagram of the spacer component provided in an embodiment of the present invention.

[0071] Figure 10This is a side view of the intervertebral fusion device provided by the present invention after ACDF surgery.

[0072] Figure 11 This is a frontal view of the intervertebral fusion device provided by the present invention after ACDF surgery.

[0073] Figure 12 The image shows a side view of the intervertebral fusion device provided by the present invention after the fusion of two vertebrae.

[0074] Figure 13 This is a side view of the fused state of the two vertebrae after the removal of the bone plates and linear components.

[0075] Figure label:

[0076] 100-Interbody fusion device; 10-Fusion device body; 11-Bone graft window; 12-End face; 121-Point; 13-Entrance; 14-Spherical cavity; 15-Allowing groove; 20-Bone plate; 21-Main plate body; 211-Slot; 212-Pin hole; 213-Center hole; 214-Counterset groove; 22-Secondary plate body; 221-Attachment plate part; 2211-Through hole; 222-Insertion plate part; 2221-Tongue; 2222-Elastic strip; 2223-Positioning hole; 23-Pin shaft; 231-Threaded hole; 232-Radial hole; 2 33-Top bead; 234-Tightening pin; 2341-Conical surface; 2342-Cylindrical section; 30-Linear component; 31-Tube body; 311-Expandable part; 3111-Expanding body; 3112-Annular groove; 312-Counterhole; 32-Rod body; 321-Conical end; 322-Screw; 33-Elastic connecting component; 331-Flange ring; 332-Sleeve body; 333-Wave wall; 341-Drive nut; 342-Locking nut; 40-Bone screw; 50-Spacer component; 51-Finger elastic strip; 52-Sleeve-shaped body.

[0077] 1000 - Vertebra; 1001 - Intervertebral space; 2000 - Fresh bone; 3000 - Peripheral new bone. Detailed Implementation

[0078] like Figure 3 and combined Figure 10As shown, an embodiment of the present invention discloses an intervertebral fusion device 100 used in anterior cervical discectomy and fusion (ACDF). The device includes three components: a fusion body 10 for implantation into the intervertebral space 1001 of two cervical vertebrae 1000, a bone plate 20 for fixing the two vertebrae 1000 corresponding to the fusion body 10, and a linear component 30 that is attached to the bone plate 20 and the fusion body 10 at both ends, respectively.

[0079] In this invention, the linear component 30 should be understood as: the component extends substantially along a straight line, and under the definition that the direction of extension is called the length direction and other directions are called the radial direction, the component has a large length-to-diameter ratio. Therefore, in this invention, the linear component 30 can also be called an elongated component.

[0080] like Figure 3 and combined Figure 10 As shown, the surface of the fusion device body 10 has two opposite end faces 12. When the fusion device body 10 is implanted into the intervertebral space 1001 where the human intervertebral disc has been removed, the two end faces 12 of the fusion device body 10 face towards the endplates of the upper and lower vertebrae 1000 where the surface cartilage has been scraped off. Thus, in the early stage after ACDF surgery, the fusion device body 10 replaces the human intervertebral disc to maintain the intervertebral space 1001 and provides support. On the other hand, the fusion device body 10 forms contact pressure with the endplates of the vertebrae 1000 through the end faces 12, stimulating the endplates to grow new bone towards the opposite vertebrae 1000, thereby fusing the vertebrae 1000 with the fusion device body 10. Preferably, a pointed body 121 with a sharp point is machined on each end face 12 of the fusion body 10. Under contact pressure, the tip of the pointed body 121 is inserted into the surface of the endplate, thereby restricting the displacement of the fusion body 10 and stimulating the rapid growth of new bone. In this invention, the pointed body 121 with a matrix arrangement of quadrangular vertebral structures is obtained by machining triangular grooves arranged in sequence and crisscrossing on the end face 12.

[0081] The fusion device body 10 also has a bone graft window 11 extending through its two end faces 12. Before implanting the fusion device body 10 into the intervertebral space 1001, the bone graft window 11 is filled with bone tissue or bone growth inducing material to increase new bone density and induce new bone growth during bone fusion after ACDF surgery. The filled bone tissue can be allogeneic dry bone or allogeneic fresh bone shavings 2000 obtained during cartilage removal. In this invention, the bone graft window 11 is processed into a rectangular cross-section structure, and the size of the window of the bone graft window 11 is larger than the size of the central region of the bone graft window 11. During the ACDF postoperative period, the new bone growing from the endplates of the two vertebrae 1000 fuses with each other through the bone graft window 11.

[0082] The fusion device body 10 can be made of a biocompatible metallic material or a biocompatible non-metallic material, such as titanium alloy (e.g., Ti-6Al-4V) or polyether ether ketone (PEEK) non-metallic material. Preferably, the fusion device body 10 is made of polyether ether ketone.

[0083] like Figure 10 and Figure 11 and combined Figure 3 As shown, the bone plate 20 is positioned on the anterior side of the cervical vertebrae and simultaneously spans two vertebrae 1000 corresponding to the fusion device body 10 for fixing the two vertebrae 1000 before bone fusion and for supporting the two vertebrae 1000 together with the fusion device body 10. Specifically, the bone plate 20 has two through holes 2211 located on its upper part and two through holes 2211 located on its lower part. The two through holes 2211 on the upper part are opposite to the anterior surface of the vertebrae 1000 above the fusion device body 10, and the two through holes 2211 on the lower part are opposite to the anterior surface of the vertebrae 1000 below the fusion device body 10. When the fusion device body 10 is implanted into the intervertebral space 1001 and the bone plate 20 needs to be installed, the bone screws 40 are inserted laterally through the two upper through holes 2211 and screwed into the upper vertebra 1000, and the bone screws 40 are inserted laterally through the two lower through holes 2211 and screwed into the lower vertebra 1000. Thus, the two vertebrae 1000 are fixed by means of the bone plate 20. Preferably, the distance between the two upper through holes 2211 and the distance between the two lower through holes 2211 are greater than the width of the middle region of the bone plate 20, thereby reducing the contact between the bone plate 20 and the anterior surface of the vertebra 1000 and increasing the stability of the bone screws 40.

[0084] Regardless of whether the bone plate 20 is a single structure or a split structure assembled from multiple plates (the structure will be described below), the main body of the bone plate 20 is made of titanium alloy material with a high elastic modulus, specifically Ti-6Al-4V titanium alloy material, which gives the bone plate 20 excellent bending and torsional resistance.

[0085] like Figure 10 As shown, the linear component 30 has a proximal end and a distal end. The proximal end of the linear component 30 is used to attach to the middle region of the bone plate 20, and the distal end of the linear component 30 extends into the intervertebral space 1001 to attach to the anterior side of the fusion cage body 10 to limit displacement of the fusion cage body 10 and maintain the fusion cage body 10 in the middle region of the intervertebral space 1001. Thus, the fusion cage body 10 and the bone plate 20 are connected through the linear component 30.

[0086] The linear component 30 provided by the present invention, as well as the fusion body 10 and the bone plate 20 that cooperate with the linear component 30, have the following structures.

[0087] like Figure 4 , Figure 6 , Figure 10As shown, the linear component 30 includes a tube 31 and a rod 32. An expandable portion 311 is disposed at the distal end of the tube 31. This expandable portion 311 includes a plurality of circumferentially arranged expandable bodies 3111, which are separated by V-shaped slits cut into a quasi-ellipsoidal solid at the distal end of the tube 31. The plurality of expandable bodies 3111 form an expandable hole that communicates internally with the tube hole of the tube 31. An annular groove 3112 is machined in the region where the root of the expandable body 3111 is located by removing material, thereby creating a weak point at the root of the expandable body 3111. Thus, the elastic deformation of the expandable body 3111 occurs at the root of the expandable body 3111. The rod 32 passes through the tube 31 and is movable along the axial direction of the tube 31. A tapered end 321 is disposed at the distal end of the rod 32, and a screw 322 of a certain length is machined at the proximal end of the rod 32. When assembling the linear component 30, the proximal end of the rod 32 passes through the distal end of the tube 31, and the rotation of the rod 32 relative to the tube 31 is restricted by a key-like engagement. The screw 322 of the rod 32 eventually reaches the proximal end of the tube 31, and the tapered end 321 of the rod 32 reaches the expandable portion 311 at the distal end of the tube 31. Before applying an axial force toward the proximal end (or front side) to the rod 32, a portion of the tapered end 321 of the rod 32 protrudes from the end of the expandable portion 311, all the expansion bodies 3111 are in the reset state, and the expandable portion 311 is in the contracted state. When an axial force toward the proximal end is applied to the rod 32, the rod 32 moves toward the proximal end as a whole, and the tapered end 321 at the distal end enters the expandable portion 311 so that the expandable portion 311 is forced to expand into a spherical shape through the engagement of the tapered end 321 with the expansion body 3111. A countersunk hole 312 with a diameter larger than that of the tube hole of the tube body 31 is machined at the proximal end of the tube body 31. The screw 322 of the rod body 32 extends into the countersunk hole 312 without protruding from the end face of the far end of the tube body 31. A drive nut 341 is fitted on the screw 322. There is a reserved gap between the drive nut 341 and the hole wall of the countersunk hole 312 to allow the corresponding force-applying tool to be inserted into the countersunk hole 312 to screw the drive nut 341. By screwing the drive nut 341, the drive nut 341 abuts against the bottom of the hole of the countersunk hole 312 and forms a helical transmission with the screw 322 to drive the rod body 32 as a whole to move toward the proximal end, thereby forcing the expandable part 311 to expand. By screwing the drive nut 341 in the opposite direction and relying on the elastic reset of the expansion body 3111, the expandable part 311 contracts.

[0088] like Figure 4 and Figure 5As shown, from the front to the rear of the fusion body 10, an inlet 13, a spherical cavity 14 communicating with the inlet 13, and a clearance groove 15 communicating with the spherical cavity 14 are sequentially machined, such that the minimum diameter of the inlet 13 is smaller than the diameter of the spherical cavity 14. When the distal end of the linear component 30 is attached to the fusion body 10, the expandable part 311 is reset to the contracted state by reverse screwing the drive nut 341, so that the expandable part 311 in the contracted state enters the spherical cavity 14 through the inlet 13 of the fusion body 10. The portion of the tapered end 321 of the rod 32 protruding from the expandable part 311 is exactly located in the clearance groove 15 so that the expandable part 311 can enter the spherical cavity 14. By turning the drive nut 341 forward, the expandable part 311 can be expanded to a diameter larger than that of the inlet 13. Thus, the expandable part 311 is restricted from dislodging from the spherical cavity 14, and the distal end of the linear component 30 is attached to the front side of the fusion body 10. The fusion body 10 is allowed to oscillate freely within a certain angle range relative to the linear component 30. By continuing to turn the drive nut 341 forward, the expandable part 311 expands further and generates a certain contact force with the spherical cavity 14. The friction generated by the contact force allows the fusion body 10 to oscillate under a certain damping. By tightening the drive nut 341, the expandable part 311 is brought into close contact with the spherical cavity 14, locking the fusion body 10 to completely fix the fusion body 10 to the distal end of the linear component 30.

[0089] like Figure 4As shown, a groove 214 is formed on the outer side of the middle part of the bone plate 20. A central hole 213 is formed at the bottom of the groove 214. The diameter of the central hole 213 is larger than the outer diameter of the proximal end of the tube body 31 of the linear component 30. An elastic connecting component 33 is arranged in the groove 214. The elastic connecting component 33 includes an integrally formed flange ring 331 and a sleeve 332. The flange ring 331 is attached and fixed to the bottom of the groove 214 by means such as fastening, welding, or heat bonding. The sleeve 332 is coaxial with the central hole 213. External threads are machined on the sleeve wall of the sleeve 332. Multiple circumferentially arranged V-shaped notches are machined on the sleeve wall to form multiple circumferentially arranged clamping walls. A locking nut 342 is fitted in the area where the clamping wall is located. The locking nut 342 is configured with a tapered thread hole 231. Thus, the clamping wall can be radially contracted by turning the locking nut 342. The junction area between the flange ring 331 and the sleeve 332 is processed with a corrugated wall 333 by stamping, thermoforming, etc. This corrugated wall 333 allows the sleeve 332 to swing when subjected to a certain bending moment. Therefore, the elastic connector allows the sleeve 332 to swing in a way that provides elastic damping. The distal end of the tube 31 of the linear component 30 passes through the sleeve 332. Thus, by tightening the locking nut 342, the elastic wall is released, allowing the tube 31 to move. By tightening the locking nut 342 in the opposite direction, the elastic wall clamps the tube 31 to restrict its movement. This allows the position of the fusion device body 10 in the intervertebral space 1001 to be adjusted. Furthermore, the bone plate 20 allows the linear component 30 to swing slightly while providing a certain degree of support through the elastic connector 33.

[0090] The tube body 31 and rod body 32 of the linear component 30 are preferably made of a biocompatible titanium alloy. More preferably, the rod body 32 is made of a Ti-6Al-4V titanium alloy with a high elastic modulus; the tube body 31 is made of a Ti-6Al-4V titanium alloy with a high elastic modulus and a Ti-13Nb-13Zr titanium alloy or a Ti-12Mo-6Zr-2Fe titanium alloy with strong elastic deformation capacity and relatively low elastic modulus. Specifically, the main body section, including the proximal section, is made of Ti-6Al-4V titanium alloy, and the proximal section, including the expandable part 311, is made of Ti-13Nb-13Zr titanium alloy or Ti-12Mo-6Zr-2Fe titanium alloy. The main body section and the proximal section can be fixedly attached by welding, anchoring, or threaded connection. By selecting Ti-13Nb-13Zr titanium alloy or Ti-12Mo-6Zr-2Fe titanium alloy, the expandable part 311 has excellent elastic deformation capacity. The elastic connecting component 33 is preferably made of Ti-12Mo-6Zr-2Fe titanium alloy, so that the corrugated plate of the elastic connecting component 33 has excellent elastic deformation capability.

[0091] like Figure 4 and Figure 6As shown, in some preferred configurations of the linear component 30, the outer peripheral surface of the segment of the tube body 31 located in the intervertebral space 1001 is a conical cylindrical surface with a diameter at the distal end smaller than that at the proximal end. Furthermore, after the expandable portion 311 contracts due to the elastic reset of the expandable body 3111, the radial dimension of the expandable portion 311 is smaller than the radial dimension of the inlet 13 and smaller than the radial dimension at the distal end of the conical cylindrical surface of the tube body 31.

[0092] The following describes the process of performing ACDF surgery using the aforementioned interbody fusion device 100.

[0093] First, the patient's head is tilted back, and an incision is made in the corresponding area of ​​the neck. Anterior cervical tissues such as the trachea and esophagus are then separated to expose the intervertebral disc to be replaced and the corresponding upper and lower vertebrae 1000. Next, a retractor is used to separate the two vertebrae 1000 to increase the distance between them. The intervertebral disc is removed using a scalpel, and the cartilage on the surface of the endplates of the two vertebrae 1000 is scraped away using a scraper. Then, a fusion device body 10 mold is inserted into the middle region of the intervertebral space 1001 for trial molding to select a suitable sized fusion device body 10.

[0094] Then, the expandable part 311 at the distal end of the linear component 30 is inserted into the spherical cavity 14 at the front of the fusion device body 10. The expandable part 311 is expanded by screwing the drive nut 341 at the proximal end, thereby locking or semi-locking the fusion device body 10 with the distal end of the linear component 30. The fusion device body 10 is delivered to the middle region of the intervertebral space 1001 by attaching a delivery tool to the proximal end of the linear component 30 through the linear component 30. The position of the fusion device body 10 is then finely adjusted to adjust the fusion device body 10 to the appropriate position.

[0095] Then, the retractor is removed so that the two vertebrae 1000 naturally press against the two end faces 12 of the fusion body 10. Then, the drive nut 341 is turned in the opposite direction to slightly contract the expandable part 311, thereby allowing the linear component 30 to swing omnidirectionally relative to the fusion body 10, thereby allowing adjustment of the spatial position of the proximal end of the linear component 30.

[0096] Then, the bone plate 20 is attached to the front of the cervical spine and simultaneously straddles the upper and lower vertebrae 1000 corresponding to the fusion device body 10. The bone plate 20 is then adjusted to a suitable position (the suitable position specifically refers to a position that is suitable for inserting the bone screw 40, minimizes the impact on the anterior cervical tissue, and minimizes the concentrated contact force with the anterior surface of the vertebrae 1000). Then, before the bone screw 40 is screwed into the vertebrae 1000 through the through hole 2211 of the bone plate 20, the distal end of the tube 31, after its spatial position has been adjusted, passes through the central hole 213 of the bone plate 20 and the sleeve 332 of the elastic connecting member 33.

[0097] Then, before the locking nut 342 is held in the loosened state, the bone screw 40 is screwed into the upper and lower vertebrae 1000 through the through hole 2211. Since the distal and proximal ends of the linear component 30 are not locked, the slight movement of the position of the bone plate 20 that may be caused by screwing in the bone screw 40 will hardly cause the fusion body 10 to produce unwanted displacement and posture change. The bone plate 20 is fixed to the two vertebrae 1000 by tightening the bone screw 40.

[0098] like Figure 10 and Figure 11 As shown, firstly, the locking nut 342 is tightened from the outside of the bone plate 20 using the corresponding force application tool to fix the proximal end of the linear component 30 to the sleeve 332 of the elastic connecting component 33. Then, the drive nut 341 is screwed on using the corresponding force application tool to cause the expandable part 311 to expand so that the fusion body 10 and the linear component 30 form a semi-locked state, so that the fusion body 10 needs to overcome a certain damping to swing relative to each other.

[0099] Finally, the anterior neck tissues were repositioned and the incision was sutured.

[0100] The advantages of the aforementioned interbody fusion device 100 during and after ACDF surgery are described below:

[0101] 1. In this invention, by adding a linear component 30 and attaching both ends of the linear component 30 to the bone plate 20 and the fusion device body 10 respectively, a connection relationship is established between the bone plate 20 and the fusion device body 10. This restricts the displacement of the fusion device body 10 in the early postoperative period before the two vertebrae 1000 have fused, thereby preventing the fusion device body 10 from protruding from the posterior side of the vertebrae 1000 and compressing the spinal cord.

[0102] 2. Because the bone plate 20, through the linear component 30, can restrict the posterior movement of the fusion cage body 10, the fusion cage body 10 is allowed to be positioned in the approximate central region of the intervertebral space 1001 instead of the anterior region. This results in a more uniform and consistent peripheral space around the fusion cage body 10 for new bone growth. Figure 12 As shown, after the outer new bone 3000 finally fills the outer space and achieves fusion, the fusion body 10 is uniformly covered by the outer new bone 3000.

[0103] 3. Because the linear component 30 is a slender component with a large length-to-diameter ratio, therefore, as Figure 12 and Figure 13 As shown, the proportion of the volume of the peripheral space occupied by the segment of the linear component 30 located in the intervertebral space 1001 for the growth of the peripheral new bone 3000 is very small. Therefore, the linear component 30 hardly affects the bone fusion of the peripheral space and the mechanical properties after fusion.

[0104] 4. After the fusion of two vertebrae 1000, if discomfort is caused by the bone plate 20 affecting anterior cervical tissues such as the trachea and esophagus, requiring the removal of the bone plate 20 and the linear component 30, firstly, unscrew the bone screw 40. Then, loosen the locking nut 342 so that the proximal end of the tube 31 of the linear component 30 can disengage from the sleeve 332 of the elastic connecting component 33 and the central hole 213 of the bone plate 20, thereby allowing the bone plate 20 to be removed. Then, using the corresponding force-applying tool, tighten the drive nut 341 to cause the expandable portion 311 at the distal end of the linear component 30 to retract and return to its minimum size. Since the outer periphery of the tube 31 located in the intervertebral space 1001 is a conical surface and the radial dimension of the repositioned expandable portion 311 is smaller than the radial dimension of the distal end of the conical surface, the linear component 30 can be easily disengaged from the fused peripheral bone. Figure 3 As shown, only small bone holes are left.

[0105] 5. Since the fusion body 10 is attached to the distal end of the linear component 30 in a omnidirectional swing manner, the swing center of the fusion body 10 is located on the physical body of the fusion body 10 (specifically, the front side of the fusion body 10). Therefore, adjusting the attitude of the fusion body 10 will not cause displacement of the fusion body 10, making position adjustment and attitude adjustment almost independent of each other. However, if the swing center of the fusion body 10 is located at the connection between the bone plate 20 and the proximal end of the linear component 30, adjusting the attitude of the fusion body 10 may cause a large change in the position of the fusion body 10.

[0106] 6. During ACDF, the operation of switching the attachment state of the distal end of the linear component 30 to the fusion body 10 is performed on the outside of the bone plate 20, thereby simplifying the operation; when it is required to remove the bone plate 20 and the linear component 30, all removal operations are performed on the outside of the bone plate 20, thereby simplifying the removal operation.

[0107] 7. During bone fusion after ACDF surgery, new bone growth and fusion may cause relative positional changes between the fusion device body 10 and the bone plate 20. By forming a semi-locked connection between the fusion device body 10 and the distal end of the linear component 30, and by forming a swinging connection between the linear component 30 and the bone plate 20 under elastic damping through the elastic connection component 33, the linear component 30 is allowed to swing slightly to adapt to the relative positional changes between the fusion device body 10 and the bone plate 20. This avoids the linear component 30 pulling the fusion device body 10 relative to the vertebra 1000 and causing displacement and posture changes due to the relative positional changes between the fusion device body 10 and the bone plate 20.

[0108] This invention aims to simplify the intraoperative operation of ACDF and improve the fusion effect by adding the aforementioned linear component 30, and to simplify the intraoperative operation of ACDF and improve the fusion effect by improving the bone plate 20.

[0109] like Figure 7 , Figure 8 , Figure 10 and combined Figure 4 As shown, the improved bone plate 20 provided by the present invention includes: a main plate 21 and two secondary plates 22. The central hole 213 for the proximal end of the tube 31 of the linear component 30 is formed in the middle region of the main plate 21. Two slots 211 are configured in the main plate 21, which are respectively formed on the upper and lower end faces of the main plate 21 and extend vertically. Preferably, arc-shaped groove walls are provided on both sides of the slots 211 in the width direction. Each subplate 22 has an attachment plate portion 221 and an insertion plate portion 222 integrally formed with the attachment plate portion 221. The width of the attachment plate portion 221 is greater than the width of the insertion plate portion 222. The insertion plate portions 222 of the two subplates 22 are respectively inserted into the slots 211 from the upper and lower ends of the main plate 21 and can move vertically relative to the main plate 21 along the slots 211. Preferably, the two sides of the insertion plate portion 222 in the width direction are provided with arc-shaped edges to slide and engage with the arc-shaped groove wall of the slot 211. The two through holes 2211 in the upper part and the two through holes 2211 in the lower part of the bone plate 20 are respectively opened on the attachment plate portions 221 of the two subplates 22. Therefore, the attachment plate portions 221 of the two subplates 22 correspond to the two vertebrae 1000 respectively, and are fixed to the two vertebrae 1000 by bone screws 40 respectively. Preferably, the width of the attachment plate portion 221 of the sub-plate 22 is greater than the width of the main plate 21.

[0110] In this invention, such as Figure 8 As shown, a slightly recessed rectangular area is machined on the two plates in the middle of the attachment plate portion 221 of the sub-plate body 22 by removing material through methods such as milling. Then, the rectangular area is cut, and the trajectory of the cut seam forms a U-shape. In this way, a rectangular tongue 2221 is directly obtained from the middle plate body of the insertion plate portion 222. The side of the tongue 2221 near the attachment plate portion 221 is separated from the insertion plate portion 222 by the cut seam to form a head, while the root of the tongue 2221 is connected to the main body of the insertion plate portion 222 and located on the side away from the attachment plate portion 221. Then, by cutting the tongue 2221, a plurality of elastic strips 2222 connected to each other along the insertion direction are obtained. The plurality of elastic strips 2222 allow the tongue to elastically expand and contract in the vertical direction.

[0111] like Figure 4 and Figure 8As shown, a positioning hole 2223 is provided at the head of the tongue 2221, and a pin hole 212 is provided on the main body 21. The pin hole 212 passes through the slot 211. After the insertion plate part 222 of the sub-plate 22 is inserted into the slot 211, the pin hole 212 is opposite to the positioning hole 2223. A pin 23 is inserted through the pin hole 212, and the pin 23 passes through the positioning hole 2223 of the tongue 2221 of the sub-plate 22. Thus, when a tensile force is applied to the two sub-plates 20 in the vertical direction, the elastic strip 2222 of the tongue 2221 undergoes elastic deformation, causing the tongue to be elastically compressed. This allows the plate 20 formed by assembling the main body 21 and the two sub-plates 22 to have the ability to elastically elongate (micro-elongate) in the vertical direction. The purpose of configuring the bone plate 20 in this way is that during the fusion process of two vertebrae 1000, in the early stage of fusion, there is contact pressure between the end face 12 of the fusion device body 10 and the endplate of the vertebra 1000, which is conducive to stimulating the endplate and promoting new bone growth. However, as the new bone grows, if the bone plate 20 is a rigid body, the contact pressure between the end face 12 and the endplate will increase significantly. Excessive contact pressure will affect the growth of new bone and may cause the collapse of loose bone tissue. If the bone plate 20 has sufficient rigidity in the vertical direction and also has a certain elastic elongation capacity, the contact pressure can be suppressed within a reasonable range to accommodate the growth of new bone.

[0112] The advantages of the improved bone plate 20 provided by the present invention are: a tongue plate with elastic properties is obtained from the bone plate 20 by cutting, and the bone plate 20 is configured to achieve elastic elongation, which makes the bone plate 20 simple in structure, easy to manufacture and easy to assemble.

[0113] In some preferred structures of the bone plate 20, such as Figure 4 and Figure 8As shown, the positioning hole 2223 is configured as an elongated hole with a dimension in the length direction of the tongue 2221 larger than its dimension in the width direction of the tongue plate; the rotation of the pin 23 relative to the pin hole 212 is restricted by a method such as a key fit; a threaded hole 231 is provided at the end of the pin 23, and a radial hole 232 is provided on the pin 23, passing through the threaded hole 231. The radial hole 232 faces the wall of the positioning hole 2223 in the insertion direction of the insertion plate portion 222. A top ball 233 is provided in the radial hole 232, and a locking pin 234 with a conical surface 2341 at its head is screwed into the threaded hole 231. By screwing the locking pin 234, the conical surface 2341 pushes against the top ball 233 and moves radially outward to push against the wall of the positioning hole 2223. Preferably, the external thread of the locking pin 234 and the threaded hole 231 of the pin 23 are configured to interlock to prevent the locking pin 234 from automatically loosening. Preferably, a cylindrical section 2342 is provided between the conical section 2341 and the external thread section of the clamping pin 234, so that after the top ball 233 moves outward, the cylindrical section 2342 of the clamping pin 234 contacts the top ball 233 instead of the conical section 2341, thereby preventing the top ball 233 from applying an outward axial force to the clamping pin 234.

[0114] The above-mentioned fastening pin 234, top bead 233, elongated hole, and other related structures have the following advantages:

[0115] In ACDF surgery, in order to generate sufficient initial contact pressure between the endplates of the two vertebrae 1000 and the end face 12 of the fusion body 10, when fixing the two vertebrae 1000 with traditional bone plates, a clamping tool (or pressure-applying workpiece) is needed to apply a certain pre-tightening pressure to the two vertebrae 1000. This is to ensure that after the bone plates are installed, sufficient contact pressure can be obtained between the endplates of the vertebrae 1000 and the end face 12 of the fusion body 10. However, this has disadvantages. On the one hand, the clamping tool needs to be positioned on the vertebrae 1000 to apply the pre-tightening force. On the other hand, the clamping tool may interfere with the turning tool turning the bone screws 40, thereby increasing the difficulty of operation.

[0116] However, when fixing the vertebrae 1000 using the bone plate 20 provided by the present invention, there is no need to use clamping tools to provide pre-tightening force for the two vertebrae 1000. Therefore, there is no need to configure target points and there is no interference when turning the bone screws 40. After the bone plate 20 is installed, the top bead 233 is moved outward by turning the top screw 234 on the bone plate 20. The outward movement of the top bead 233 will compress the tongue 2221 in real time by pushing against the hole wall of the positioning hole 2223. Thus, the tongue 2221 drives the subplate body 22 to move towards the main body 21 or generates a movement tendency, thereby increasing the contact pressure between the endplate of the vertebrae 1000 and the end face 12 of the fusion device body 10, so that it obtains sufficient initial contact pressure.

[0117] In some preferred structures of the bone plate 20, such as Figure 9 and Figure 10 As shown, a spacer 50 is provided at the inner end of each through hole 2211 of the bone plate 20. The spacer 50 has a sleeve-shaped main body 52 and a plurality of finger-shaped elastic strips 51 integrally formed with the sleeve-shaped main body 52 and arranged circumferentially to form a trumpet shape. An insertion hole is provided at the inner end of the through hole 2211, so that the sleeve-shaped main body 52 is inserted into the insertion hole and the plurality of finger-shaped elastic strips 51 forming a trumpet shape are located on the inner side of the bone plate 20. The spacer 50 serves two purposes: First, multiple finger-shaped elastic strips 51 separate the bone plate 20 from the vertebra 1000, allowing only the spacer 50 to contact the anterior surface of the vertebra 1000, while the bone plate 20 does not contact the anterior surface of the vertebra 1000. This avoids stress concentration caused by contact between the bone plate 20 and the anterior surface of the vertebra 1000, thus the spacer 50 functions as a regular spacer. Second, if the area of ​​the anterior surface of the vertebra 1000 corresponding to the spacer 50 is uneven, each finger-shaped elastic strip 51 will conform to the uneven surface and undergo its own compliant elastic deformation, thereby dispersing the contact force between the spacer 50 and the anterior surface of the vertebra 1000 and avoiding stress concentration in that area. This prevents stress concentration in the area where the bone screw 40 is inserted due to the use of a regular spacer. Preferably, the spacer 50 is made of Ti-13Nb-13Zr titanium alloy.

[0118] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. An intervertebral fusion device, comprising: Comprise: a fusion cage body having two end faces each configured with a plurality of spikes and a bone graft window penetrating through the two end faces, the fusion cage body being implanted into an intervertebral space with the two end faces respectively facing the end plates of two vertebrae; a bone plate having a through hole at each of an upper portion and a lower portion, the bone plate being arranged on the anterior side of the cervical vertebrae and straddling the two vertebrae defining the intervertebral space, the through holes at the upper and lower portions being respectively opposite to the two vertebrae; bone screws passing through the through holes at the upper and lower portions of the bone plate and being screwed into the vertebrae to fix the bone plate to the two vertebrae respectively; a linear member having a proximal end and a distal end, the proximal end of the linear member being attached to the middle portion of the bone plate, the distal end of the linear member extending into the intervertebral space and being attached to the anterior side of the fusion cage body to limit the displacement of the fusion cage body and maintain the fusion cage body in the middle region of the intervertebral space; the distal end of the linear member being attached to the anterior side of the fusion cage body in a manner allowing the fusion cage body to be swiveled and locked after swiveling; the linear member comprising: a tubular body having a proximal end passing through the bone plate and being exposed to the anterior side of the bone plate and being configured with a counterbore, the tubular body having a distal end configured with an expandable portion surrounded by a plurality of expansion bodies; the anterior side of the fusion cage body being configured with an entrance and a spherical cavity behind the entrance, the expandable portion being used to extend into the spherical cavity through the entrance; a rod body passing through a rod hole of the tubular body, the rod body having a proximal end configured with a screw rod and a distal end configured with a tapered end, the rod body being driven to move forward and force the expansion bodies to expand into a spherical shape by cooperating with the tapered end and the expansion bodies of the expandable portion to tighten the spherical cavity to lock the fusion cage body and the distal end of the tubular body; a drive nut being sleeved on the screw rod of the rod body and being located in the counterbore of the proximal end of the tubular body, so that a force applying tool can extend into the counterbore of the tubular body from the anterior side of the bone plate to act on the drive nut to drive the rod body to move towards the anterior side by screwing the nut; the bone plate comprising a main plate body and two auxiliary plate bodies cooperating with the main plate body, the through holes at the upper and lower portions of the bone plate being arranged on the two auxiliary plate bodies respectively; wherein: each auxiliary plate body is elastically moved in the upward and downward directions relative to the main plate body.

2. The intervertebral fusion device of claim 1 wherein, The outer peripheral surface of the section of the tubular body in the intervertebral space is a tapered cylindrical surface with a smaller diameter on the distal end side than on the proximal end side, and after the expansion bodies are elastically reset so that the expandable portion is contracted, the radial dimension of the expandable portion is smaller than the radial dimension of the entrance and smaller than the radial dimension of the distal end of the tapered cylindrical surface of the tubular body.

3. The intervertebral fusion device according to claim 1, wherein: a recess is formed on the anterior side of the bone plate, a central hole penetrating through the bone plate is formed on the bottom of the recess, and the proximal end of the tubular body passes through the central hole. The sink is provided with an elastic connecting component, the elastic connecting component has a flange ring and a sleeve body integrally formed with the flange ring, the flange ring is attached and fixed with the sink, the proximal end of the pipe body is provided through the sleeve body, the sleeve wall of the sleeve body is provided with an opening to separate the sleeve wall into circumferentially arranged clamping walls, the section where the opening is located is provided with external threads, the sleeve body is provided with a locking nut, the clamping wall is clamped or released by rotating the locking nut to make the pipe body; wherein: The intersection area of the flange ring and the sleeve body is provided with a wave wall, and the wave wall is deformed elastically to allow the sleeve body to move.

4. The intervertebral fusion device as recited in claim 1, wherein, Two slots are arranged on the main plate body, and the two slots respectively extend vertically from the upper and lower end faces of the main plate body; the auxiliary plate body has an attachment plate portion and an insertion plate portion integrally formed with the attachment plate portion, and the insertion plate portions of the two auxiliary plate bodies are respectively inserted into the two slots from above and below the main plate body and can move along the slots; wherein: A tongue portion is cut in the middle region of the insertion plate portion, and the head portion of the tongue portion faces the attachment plate portion; the tongue portion is obtained by cutting to have elastic strips connected to each other, so that the tongue portion can be elastically deformed, and the head portion of the tongue portion is provided with a positioning hole; The region opposite to the positioning hole of the main plate body is provided with a pin hole, and a pin shaft is arranged at the pin hole, the pin shaft passes through the positioning hole, so that when the auxiliary plate body moves away from the main plate body, the elastic strips are elastically deformed by the limiting of the head portion of the tongue portion by the pin shaft to allow the auxiliary plate body to elastically move.

5. The intervertebral fusion device of claim 4, wherein: The positioning hole is configured as a long circular hole with a size in the length direction of the tongue portion greater than a size in the width direction of the tongue plate; A threaded hole is formed at the end of the pin shaft, a radial hole is formed in the pin shaft and passes through the threaded hole, the radial hole faces the hole wall of the positioning hole in the insertion direction of the insertion plate portion, a top bead is arranged in the radial hole, and a top nail with a conical head is screwed into the threaded hole, the conical surface of the top nail pushes the top bead radially outward to push against the hole wall of the positioning hole by rotating the top nail.

6. The intervertebral fusion device as recited in claim 1, wherein, A spacing component is arranged at the inner end of the through hole, the spacing component has a sleeve body and a plurality of finger-shaped elastic strips integrally formed with the sleeve body and arranged circumferentially to form a horn-shaped outer shape; the inner end of the through hole is provided with a insertion hole, the sleeve body is inserted into the insertion hole, and the bone screw passes through the sleeve body; wherein: When the head of the bone screw is screwed into the vertebra and tightened, the finger-shaped elastic strips are deformed to fit and press against the front surface of the vertebra.

7. The intervertebral fusion device as recited in claim 1, wherein, The rear side of the spherical cavity of the cage body is provided with a avoiding groove for accommodating the conical end of the distal end of the rod of the linear component.

8. The intervertebral fusion device as recited in claim 1, wherein, The cage body is made of polyether ether ketone material; the cross section of the bone graft window of the cage body is rectangular; the size of the window of the bone graft window is greater than the size of the middle region of the bone graft window; the sharp body is a plurality of rectangularly arranged four-pyramid bodies.

9. The intervertebral fusion device as recited in claim 1, wherein, The bone plate is made of titanium alloy material, the tube body and the rod body of the linear component are both made of titanium alloy material, and the tube body is made of two different titanium alloy materials; the titanium alloy for making the bone plate and the rod body includes Ti-6Al-4V; the titanium alloy material for making the tube body includes: Ti-6Al-4V, and any one of Ti-13Nb-13Zr and Ti-12Mo-6Zr-2Fe.

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