Interbody fusion cage device

Abstract

The objective of the present invention is to provide an interbody fusion cage device which: has bone fusion protrusions and bone fusion holes on an upper plate and a lower plate of a cage that is to be inserted between vertebrae, and has a grid-shaped elasticity providing body, formed over both side plates and a rear plate, for adjusting an elastic modulus of the cage to an elastic modulus of a bone such that bone fusion between the vertebrae and the cage is facilitated and subsidence in which the cage penetrates the vertebrae can be prevented; has diagonal screw insertion holes, formed on a front plate of the cage, to be structured such that the insertion direction of fixing screws can be vertically and horizontally adjusted and thus a margin for the direction in which the fixing screw is inserted into the vertebrae from the outside of the cage can be provided, thereby enabling convenience and accuracy of surgery for an operator to be improved; and has a screw fastening hole formed on the front plate of the cage such that a separation prevention screw for preventing the separation of the fixing screw can fastened thereto, and thus the loosening or separation of the fixing screw insertively fastened to the vertebrae from the cage can be prevented.

Description

Intervertebral fusion prosthesis device

[0001] The present invention relates to an intervertebral fusion prosthesis device, and more particularly, to an intervertebral fusion prosthesis device that is inserted between vertebrae to enable fusion, thereby providing support and maintaining a gap between the vertebrae.

[0002] As is well known, the human spine is the vertical axis of the body and is composed of seven cervical vertebrae, twelve thoracic vertebrae, five sacrum vertebrae, and four coccyx vertebrae, and includes intervertebral discs, which are disc-shaped cartilaginous structures that connect the vertebrae.

[0003] Recently, with the increase in the incidence of lumbar degenerative diseases such as spinal stenosis and degenerative spine due to the aging society, bone fusion surgery is being widely performed to remove the herniated and deformed intervertebral disc and then insert a spinal fusion cage into the removed space to restore the original disc height of the vertebral body and fuse the vertebral bodies into one.

[0004] To elaborate, the spinal fusion is a surgical procedure that involves removing a damaged disc and then implanting a cage to fuse the adjacent vertebrae above and below the removed disc. It is used for the treatment of structural abnormalities such as herniated discs, as well as for the purposes of spinal bone transplantation, fixation of spinal disc herniation and curvature, restoration of a dislocated vertebral body, and restoration of the height of a fractured vertebral body.

[0005] Meanwhile, the conventional cage for fusion of the vertebrae is manufactured using metal or polymer materials, and is manufactured with a structure having a chamber body for filling bone growth material, and an upper opening and a lower opening formed at the upper and lower portions of the chamber body.

[0006] Accordingly, the spinal fusion surgery can be performed by a step of removing a damaged disc, a step of filling a chamber body with a bone growth material (autologous bone or artificial bone, etc.) through the upper opening of the cage, and a step of inserting a cage filled with the bone growth material into the space where the disc was removed, and the neighboring vertebrae above and below can be fused by the bone growth material filled in the chamber body of the cage.

[0007] However, conventional spinal fusion cages have the following problems.

[0008] First, the existing spinal fusion cages are made of titanium and have been widely used due to their excellent biocompatibility and stability. However, the elastic modulus of the titanium alloy, which is the cage material, is 110 GPa, and the elastic modulus of the cancellous bone of the vertebral body into which the cage is inserted is 1.34 GPa, which is a difference of about 100 times in elastic modulus, so there is a problem of the cage sinking into the vertebral body after surgery.

[0009] To elaborate, after surgery, the rigid titanium cage digs into the relatively weak vertebral body, causing subsidence. This subsidence results in a lowering of the height of the vertebral body, which leads to further recurrence of spinal stenosis and causes reoperation.

[0010] Second, although a certain amount of bone growth material must be filled inside the chamber body of the cage, there is a problem that some of the bone growth material is lost during the impact load of inserting the cage between the vertebrae from which the disc has been removed, so that fusion between the neighboring vertebrae above and below does not occur accurately, and accordingly, the insertion of an additional fixator increases the problem of surgical time and cost.

[0011] Third, the surgeon must insert a fixing screw from the cage into the vertebrae to fix the cage inserted between the vertebrae during surgery. However, since the screw hole structure of the cage is formed in a structure that guides the direction in which the fixing screw is inserted in only one fixed direction, there is a problem that the accuracy of the surgery is reduced and the inconvenience of the surgery occurs.

[0012] Fourth, after surgery to insert a cage between the vertebrae and insert a fixing screw from the cage into the vertebrae to fix the cage, there is a problem of loosening and detachment of the fixing screw.

[0013] The present invention has been devised to solve the above-mentioned problems of the related art, and the purpose of the present invention is to provide an intervertebral body fusion prosthesis device in which bone fusion projections and bone fusion holes are formed on the upper and lower plates of a cage inserted between vertebrae, and a lattice-shaped elastic member is formed across the two sides and the rear plate to match the elastic coefficient of the cage to the elastic coefficient of the bone, so that not only bone fusion between the vertebrae and the cage is easily achieved, but also the phenomenon of the cage digging into the vertebral body is prevented.

[0014] In addition, the present invention provides an intervertebral body fusion prosthesis device that can improve the convenience and accuracy of the surgeon's operation by forming a diagonal screw insertion hole formed on the front plate of the cage in a structure that can adjust the insertion direction of the fixing screw in all directions, thereby providing a margin for the direction in which the fixing screw is inserted from the outside of the cage into the inside of the vertebra.

[0015] In addition, the present invention aims to provide an intervertebral body fusion prosthesis device that can prevent loosening or detachment of a fixing screw inserted into a vertebra from a cage by forming a screw fastening hole in the front plate of the cage so that a screw for preventing detachment of the fixing screw can be fastened.

[0016] In order to achieve the above object, the present invention provides an intervertebral body fusion prosthesis device comprising: a cage having a structure in which a bone graft filling hole is formed vertically in the central portion, a plurality of bone fusion protrusions and bone fusion holes are formed on the surfaces of the upper and lower plates, a diamond lattice-shaped elastic member is formed across the two sides of the upper and lower plates and the back plate to match the elastic modulus of the cage to the elastic modulus of the bone, a first oblique screw insertion hole inclined upwardly and a second oblique screw insertion hole inclined downwardly are formed on both sides of the front plate, and a screw fastening hole is formed in the central portion; a fixing screw that is press-fastened into the bone through the first oblique screw insertion hole and the second oblique screw insertion hole while the cage is inserted between the bones at the surgical site; and a screw for preventing detachment that is inserted and fastened through the screw fastening hole into the bone graft filling hole and restrains the head of the fixing screw.

[0017] In addition, it is characterized in that a communication portion is formed between the first diagonal screw insertion hole and the screw fastening hole and between the second diagonal screw insertion hole and the screw fastening hole on the front plate of the cage so that the head of the separation-prevention screw can enter the entrance side of the first diagonal screw insertion hole and the second diagonal screw insertion hole to restrain the head of the fixing screw.

[0018] Preferably, the inner diameters of the first diagonal screw insertion hole and the second diagonal screw insertion hole are formed to a size that allows the insertion direction of the fixing screw to be adjusted from 10° to 60° in the up-down direction and from 1° to 20° in the left-right direction, so as to provide a margin for the insertion direction of the fixing screw toward the inside of the bone from the first diagonal screw insertion hole and the second diagonal screw insertion hole.

[0019] In addition, the cage is characterized in that a rectangular cross-section clamping groove is cut and formed on the upper side of the entrance of the screw fastening hole in the front plate of the cage so that a surgical clamping tool for inserting the cage into the surgical site between bones is clamped.

[0020] In addition, the surface of the upper and lower plates is characterized by having a mesh net attached thereto to induce bone union.

[0021] Preferably, the pitch of the first screw thread formed at the front end of the fixing screw is formed narrower than the pitch of the second screw thread formed at the distal end, so that the first screw thread is fastened to a hard bone portion with a high density forming the exterior of the bone, while the second screw thread is fastened to a loose bone portion with a low density forming the interior of the bone.

[0022] In addition, the screw end of the anti-separation screw is characterized by having a cross-shaped cut and a gap-shaped anti-separation section formed to prevent loosening.

[0023] Through the means for solving the above-mentioned problem, the present invention provides the following effects.

[0024] First, by forming bone fusion projections and bone fusion holes on the upper and lower plates of the cage inserted between the vertebrae, and further attaching a mesh net to the upper and lower plates, bone fusion between the vertebrae and the cage can be easily achieved.

[0025] Second, by forming a diamond-lattice-shaped elastic member across the two sides and the back plate of the cage to match the elastic coefficient of the cage to the elastic coefficient of the bone, the phenomenon of the cage sinking into the vertebral body after surgery due to a large difference in the elastic coefficients of the cage and the bone can be prevented.

[0026] Third, a diagonal screw insertion hole for inserting a fixing screw is formed in the front plate of the cage, and a margin is provided to allow the insertion direction of the fixing screw to be adjusted up, down, left, and right, thereby allowing the surgeon to provide a margin for the direction in which the fixing screw is inserted, that is, for the direction in which the fixing screw is inserted from the outside of the cage to the inside of the vertebra, thereby improving the convenience and accuracy of the surgeon's operation.

[0027] Fourth, by forming a screw fastening hole in the front plate of the cage so that a screw for preventing detachment can be fastened to prevent detachment of the fixing screw, loosening or detachment of the fixing screw inserted into the vertebra from the cage can be prevented.

[0028] Fifth, a clamping groove cut in a square groove shape is formed on the upper side of the entrance of the screw-fastening hole formed on the front plate of the cage, so that a surgical clamping tool can be clamped to accurately position the cage between the vertebrae before the screw for preventing dislodgement is press-fastened, thereby enabling the cage to be accurately inserted between the bones at the surgical site.

[0029] Sixth, by forming the first screw thread pitch formed at the front end of the fixing screw narrower than the second screw thread pitch formed at the distal end, the first screw thread is fastened to the hard, dense bone portion (cortex bone) that forms the exterior of the bone, while the second screw thread is fastened to the loose, loose bone portion (cancellous bone) that forms the interior of the bone, thereby enabling the fixing screw to be fastened to the bone with a stronger fastening force.

[0030] Figure 1 is an exploded perspective view showing an intervertebral body fusion prosthesis device according to the present invention;

[0031] Figures 2 and 3 are assembled perspective views showing an intervertebral body fusion prosthesis device according to the present invention.

[0032] Figure 4 is a perspective view showing that a mesh net is further attached to the upper and lower plates of the intervertebral body fusion prosthesis device according to the present invention.

[0033] Figure 5 is a perspective view showing the clamping state of a surgical clamping tool for inserting the cage of the intervertebral body fusion prosthesis device according to the present invention into the bone at the surgical site.

[0034] Figure 6 is a cross-sectional view showing a surgical state in which a cage of an intervertebral body fusion prosthesis device according to the present invention is inserted between bones.

[0035] Figure 7 is a schematic diagram showing an example of a fixing screw of an intervertebral body fusion prosthesis device according to the present invention being inserted and fastened into a bone.

[0036] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0037] The attached drawing 1 is an exploded perspective view illustrating an intervertebral fusion prosthesis device according to the present invention, and drawing reference numeral 100 in each drawing is an assembled perspective view illustrating an intervertebral fusion prosthesis device according to the present invention.

[0038] The above cage (100) is inserted between vertebrae for spinal fusion to fuse vertebrae, that is, to fuse neighboring vertebrae above and below the removed location after removing a damaged disc. It is configured to include a bone graft filling hole (101) having a predetermined size formed vertically in the center, an upper plate (110) and a lower plate (120) that are symmetrical to each other, and a double-sided plate (130), a rear plate (140), and a front plate (150) that are integrally formed between the upper plate (110) and the lower plate (120).

[0039] The upper plate (110) and lower plate (120) of the cage (100) are formed with a plurality of bone fusion protrusions (102) and a plurality of bone fusion holes (103) having a sawtooth cross-section structure for bone fusion between the upper and lower vertebrae, respectively.

[0040] Furthermore, as shown in FIG. 4, a mesh net (400) may be further attached to the surfaces of the upper plate (110) and lower plate (120) to more easily induce bone fusion with the vertebrae.

[0041] Accordingly, when the cage (100) is inserted between the vertebrae, bone fusion with the vertebrae can be easily achieved through a number of bone fusion protrusions (102), bone fusion holes (103), and mesh net (400).

[0042] A diamond grid-shaped elastic member (104) is formed on the side plates (130) or the side plates (130) and the back plate (140) connected between the upper plate (110) and the lower plate (120) of the cage (100) to match the elastic coefficient of the cage (100) to the elastic coefficient of the bone.

[0043] In detail, the two side plates (130) or the two side plates (130) and the rear plate (140) of the cage (100) may be formed of an elastic member (104) having a plurality of diamond grid holes formed therein to match the elastic modulus of the cage (100) to the elastic modulus of the bone.

[0044] Accordingly, the elastic modulus of the cage (100) and the elastic modulus of the vertebra can be adjusted to a similar level due to the elastic member (104) formed on the two sides (130) of the cage (100) or the two sides (130) and the rear side (140).

[0045] Accordingly, in the past, due to a large difference in the elastic modulus of the cage and the bone, a subsidence phenomenon occurred in which the cage dug into the vertebral body after surgery, but due to the elastic member (104) formed in the cage (100) of the present invention, the elastic modulus of the cage (100) and the elastic modulus of the vertebral bone can be adjusted to a similar level, so that the subsidence phenomenon in which the cage dug into the vertebral body after surgery can be prevented, and additional recurrence of spinal stenosis and reoperation due to the existing subsidence phenomenon can be prevented.

[0046] On both sides of the front plate (150) of the cage (100), an upwardly inclined first diagonal screw insertion hole (151) and a downwardly inclined second diagonal screw insertion hole (152) are formed, and a screw fastening hole (153) for fastening a screw (300) for preventing detachment is formed in the center between the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152).

[0047] In addition, while the cage (100) is inserted between the vertebrae, which is the surgical site, a fixing screw (200) is press-fitted into the interior of the vertebrae through the first oblique screw insertion hole (151) and the second oblique screw insertion hole (152).

[0048] Preferably, the inner diameters of the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152) formed in the front plate (150) of the cage (100) can be formed to a size that allows the insertion direction of the fixing screw (200) to be adjusted by 10° to 60° in the up-down direction and by 1° to 20° in the left-right direction.

[0049] Accordingly, when the surgeon press-inserts the fixing screw (200) into the interior of the vertebrae through the first oblique screw insertion hole (151) and the second oblique screw insertion hole (152), a margin can be provided for the insertion direction of the fixing screw (200) toward the interior of the vertebrae.

[0050] That is, when the surgeon press-inserts the fixing screw (200) into the interior of the vertebrae through the first oblique screw insertion hole (151) and the second oblique screw insertion hole (152), the surgeon can arbitrarily adjust the direction for inserting the fixing screw (200) according to the shape and form of the patient's vertebrae, thereby improving the surgeon's convenience and accuracy of the surgery.

[0051] Preferably, the pitch of the first screw thread (202) formed at the tip end of the fixed screw (200) is formed narrower than the pitch of the second screw thread (203) formed at the tip end.

[0052] Accordingly, as illustrated in FIG. 7, the first screw thread (202) of the fixing screw (200) can be fastened to the hard bone portion (Cortex bone) with high density that forms the exterior of the bone, and at the same time, the second screw thread (203) can be fastened to the loose bone portion (Cancellous bone) with low density that forms the interior of the bone, and accordingly, the fixing screw (200) can be fastened to the vertebra with strong fastening force.

[0053] A screw (300) for preventing detachment is inserted and fastened from the screw fastening hole (153) formed in the front plate (150) of the cage (100) toward the bone graft filling hole (101). This screw (300) for preventing detachment serves to restrain the head (201) of the fixing screw (200) and prevent loosening or detachment of the fixing screw (200).

[0054] To this end, a communication portion (105) is formed between the first diagonal screw insertion hole (151) and the screw fastening hole (153) and between the second diagonal screw insertion hole (152) and the screw fastening hole (153) in the front plate (150) of the cage (100) so that the head (301) of the anti-separation screw (300) can enter the inlet side of the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152) to restrain the head (201) of the fixing screw (200).

[0055] Accordingly, a part of the head (201) of the fixing screw (200) inserted and fastened into the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152) is covered and locked by the head (301) of the anti-separation screw (300) inserted and fastened into the screw fastening hole (153), thereby easily preventing the fixing screw (200) from loosening or detaching.

[0056] In addition, at the end of the screw portion of the anti-separation screw (300), a four-piece anti-separation section (302) is formed in a cross shape to prevent the anti-separation screw (300) from loosening and to be opened by elastic restoring force.

[0057] Accordingly, when the anti-separation screw (300) is inserted and fastened through the screw fastening hole (153), each anti-separation section (302) formed at the end of the screw portion of the anti-separation screw (300) opens to play a locking role in fixing the anti-separation screw (300) to the current position, so that loosening or detachment of the anti-separation screw (300) can be easily prevented.

[0058] Here, the process of spinal fusion surgery using the intervertebral fusion prosthesis device of the present invention having the above-described configuration is examined as follows.

[0059] The attached Fig. 5 is a perspective view showing the clamping state of a surgical clamping tool for inserting the cage of the intervertebral fusion prosthesis device according to the present invention into the surgical site between bones, and Fig. 6 is a cross-sectional view showing the surgical state of inserting the cage of the intervertebral fusion prosthesis device according to the present invention between bones.

[0060] First, a bone graft material (e.g., autologous bone or artificial bone) is filled into the bone graft filling hole (101) of the cage (100).

[0061] Next, a cage (100) filled with bone graft material is introduced into the surgical site, i.e., between the vertebrae, using a surgical clamping tool (500).

[0062] To this end, a rectangular cross-section clamping groove (106) is cut and formed on the upper side of the entrance of the screw fastening hole (153) in the front plate (150) of the cage (100) so that a surgical clamping tool (500) can be clamped.

[0063] Accordingly, as shown in FIG. 5, after clamping the front clamping part of the surgical clamping tool (500) into the clamping groove (106) of the cage (100), the surgeon can easily insert the cage (100) between the vertebrae, which is the surgical site, by holding the rear handle of the surgical clamping tool (500).

[0064] Next, with the cage (100) inserted between the vertebrae, which is the surgical site, a fixing screw (200) is pressed into the interior of the vertebrae through the first oblique screw insertion hole (151) and the second oblique screw insertion hole (152).

[0065] At this time, the fixing screw (200) inserted through the first oblique screw insertion hole (151) is press-fitted into the upper vertebra, and the fixing screw (200) inserted through the second oblique screw insertion hole (152) is press-fitted into the lower vertebra.

[0066] As described above, the inner diameters of the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152) formed in the front plate (150) of the cage (100) are formed to a size that allows the insertion direction of the fixing screw (200) to be adjusted from 10° to 60° in the up-down direction and from 1° to 20° in the left-right direction, thereby providing a margin for the insertion direction of the fixing screw (200) toward the inside of the vertebra.

[0067] Accordingly, when the surgeon press-inserts the fixing screw (200) into the interior of the vertebrae through the first oblique screw insertion hole (151) and the second oblique screw insertion hole (152), the direction for inserting the fixing screw (200) can be arbitrarily adjusted according to the shape and form of the patient's vertebrae, thereby improving the surgeon's convenience and accuracy of the surgery.

[0068] Next, a screw (300) for preventing detachment is inserted and fastened from the screw fastening hole (153) formed in the front plate (150) of the cage (100) toward the bone graft filling hole (101) filled with the bone graft material.

[0069] At this time, the head (301) of the anti-separation screw (300) inserted and fastened into the screw fastening hole (153) covers and locks a portion of the head (201) of the fixing screw (200) inserted and fastened into the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152), thereby easily preventing the fixing screw (200) from loosening or detaching.

[0070] In addition, as each of the separation prevention ends (302) formed at the screw end of the separation prevention screw (300) opens, it serves as a locking function to fix the separation prevention screw (300), so that the separation prevention screw (300) can be easily prevented from loosening or detaching.

[0071] In this way, after the surgical process of inserting and fixing the cage (100) into the vertebrae is completed, bone fusion with the vertebrae can be easily achieved through the multiple bone fusion protrusions (102) and bone fusion holes (103) formed on the upper plate (110) and lower plate (120) of the cage (100), and the mesh net (400) attached to the upper plate (110) and lower plate (120).

[0072] Moreover, after the surgical process of inserting and fixing the cage (100) into the vertebra is completed, the elastic modulus of the cage (100) and the elastic modulus of the vertebra are adjusted to a similar level due to the elastic member (104) formed in the cage (100), so that the cage (100) can be prevented from sinking into the vertebra after the surgery, and the recurrence of additional spinal stenosis and reoperation due to the existing sinking can be prevented.

[0073] The present invention utilizes 3D printing technology and is applicable to a titanium 3D printing cage (prosthetic material) that includes an elastic and porous structure and can be used for standalone fixation.

[0074] Although the present invention has been described in detail with reference to one embodiment, the scope of the present invention is not limited to the above-described embodiment, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also included in the scope of the present invention.

Claims

1. A cage (100) having a structure in which a bone graft filling hole (101) is formed vertically in the central portion, a plurality of bone fusion protrusions (102) and bone fusion holes (103) are formed on the surfaces of the upper plate (110) and the lower plate (120), a diamond grid-shaped elastic member (104) is formed across the two-sided plates (130) and the rear plate (140) connected between the upper plate (110) and the lower plate (120) to match the elastic coefficient of the cage to the elastic coefficient of the bone, and an upwardly inclined first diagonal screw insertion hole (151) and a downwardly inclined second diagonal screw insertion hole (152) are formed on both sides of the front plate (150), and a screw fastening hole (153) is formed in the central portion; In a state where the cage (100) is inserted between the bones at the surgical site, a fixing screw (200) that is press-fitted into the bone through the first oblique screw insertion hole (151) and the second oblique screw insertion hole (152); and It is configured to include a screw (300) for preventing detachment that is inserted and fastened toward the bone graft filling hole (101) through the screw fastening hole (153) and restrains the head (201) of the fixing screw (200); An intervertebral body fusion prosthesis device characterized in that a dislocation prevention end (302) is formed in a cross shape and opened to prevent loosening at the end of the screw portion of the above dislocation prevention screw (300).

2. In claim 1, An intervertebral body fusion prosthesis device characterized in that a communication portion (105) is formed between the first oblique screw insertion hole (151) and the screw fastening hole (153) and between the second oblique screw insertion hole (152) and the screw fastening hole (153) in the front plate (150) of the cage (100) so that the head (301) of the anti-separation screw (300) can enter the entrance side of the first oblique screw insertion hole (151) and the second oblique screw insertion hole (152) to restrain the head (201) of the fixing screw (200).

3. In claim 1, An intervertebral body fusion prosthesis device characterized in that the inner diameters of the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152) are formed to a size that allows the insertion direction of the fixing screw (200) to be adjusted from 10° to 60° in the up-down direction and from 1° to 20° in the left-right direction, so as to provide a margin for the insertion direction of the fixing screw (200) toward the inside of the bone from the first diagonal screw insertion hole (151) and the second diagonal screw insertion hole (152).

4. In claim 1, A rectangular cross-section clamping groove (106) is cut and formed on the upper side of the entrance of the screw fastening hole (153) in the front plate (150) of the cage (100) so that a surgical clamping tool (500) for inserting the cage (100) into the bone, which is the surgical site, is clamped; An intervertebral body fusion prosthesis device characterized in that a mesh net (400) is further attached to the surfaces of the upper plate (110) and lower plate (120) to induce bone fusion.

5. In claim 1, An intervertebral body fusion prosthesis device characterized in that the pitch of the first screw thread (202) formed at the front end of the above-mentioned fixed screw (200) is formed narrower than the pitch of the second screw thread (203) formed at the distal end, so that the first screw thread (202) is fastened to a hard bone portion with a high density that constitutes the exterior of the bone, and at the same time, the second screw thread (203) is fastened to a loose bone portion with a low density that constitutes the interior of the bone.

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