Front insertion type artificial disc

Abstract

The present invention provides a front insertion type artificial disc having a simple structure and capable of implementing the movement of a human body, the front insertion type artificial disc, which is inserted between two adjacent vertebrae, capable of implementing the movement of the human body with a simple structure, comprising: an upper plate having an upper surface coming into contact with the upper vertebra; a lower plate having an upper surface coming into contact with the lower vertebra; and an inserter which is inserted between the upper plate and the lower plate, wherein the upper spherical surfaces of the upper plate and the inserter are in surface-contact with each other to form a spherical pair, and the inserter carries out rotational movement relative to the lower plate by using a major axis as a rotation center axis.

Description

Anteriorly inserted artificial disc

[0001] The present invention relates to an anteriorly inserted artificial disc, and more particularly, to an artificial disc that can be inserted from an anterior approach of a vertebral body.

[0002] The vertebral column is made up of 32 to 35 vertebrae that make up the torso and the intervertebral disks between the vertebrae, and is the central part of our body that connects the skull at the top and the pelvis at the bottom.

[0003] The spine is composed of 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae, and 3 to 5 coccyx vertebrae from top to bottom. In adults, 5 sacral vertebrae fuse to form 1 sacrum, and 3 to 5 coccyx fuse to form 1 coccyx.

[0004] Between the vertebrae is a cartilaginous substance called a disc. This cartilaginous substance is a soft, squishy fibrocartilage that forms a cartilaginous joint to help the spine move flexibly and acts like a ligament that fixes the spine, and absorbs and reduces the shock applied to the vertebrae. The intervertebral disc is made up of a fibrous disc on the outside and a gel-like substance called the nucleus pulposus on the inside, which maintains strength and helps distribute stress. In other words, the intervertebral disc absorbs the body's weight and shock between each vertebra, except for some parts of the cervical spine, and acts as a buffer that distributes shock like a spring. In addition, it holds the vertebrae together so they do not come out of place, separates the two vertebrae to prevent the spinal nerves from being compressed, ensures a smooth range of the spinal joint space, and plays a role in facilitating the movement of each vertebra.

[0005] As these intervertebral discs absorb and transmit vertical loads and shocks, they can cause various diseases such as spinal stenosis, osteophyte formation, disc herniation, and nerve root compression.

[0006] One treatment option for chronic, serious spinal conditions is spinal fusion. This surgical procedure involves removing an intervertebral disc and replacing it with a cage, fusing adjacent vertebrae together.

[0007] When performed on the lumbar spine, these spinal fusions can be categorized into posterior lumbar interbody fusion (PLIF), transformational lumbar interbody fusion (TLIF), lateral lumbar interbody fusion (LLIF), oblique lumbar interbody fusion (OLIF), and anterior lumbar interbody fusion (ALIF) depending on the insertion direction of the cage.

[0008] Posterior interbody fusion (PLIF) is a procedure in which an incision is made along the midline of the spine, the entire vertebral body is exposed, a portion of the posterior portion of the vertebra is removed, the disc is removed, and a PLIF cage is inserted.

[0009] Posterior interbody fusion (PLIF) is the oldest and most commonly performed spinal fusion procedure, and is essential for two- or three-body fusions. However, the surgical procedure carries a high risk of adhesions to nerves, ligaments, and muscles. The large incision area also leads to prolonged healing times. Furthermore, some individuals experience significant aftereffects.

[0010] The PLIF cage consists of a pair of small cages placed on each side, and is the smallest cage used in all spinal fusion surgeries.

[0011] Transforaminal Interbody Fusion (TLIF) is a surgical procedure in which a small incision is made along the spinal muscles on both sides to expose the vertebral body as little as possible, and the TLIF cage is inserted while removing the spinal joint area in the direction of the neural foramen. This surgical technique is suitable for single-joint surgeries because it has the advantages of less bleeding and shorter surgery time, but PLIF surgery is required when multiple areas of surgery are required. The TLIF cage is usually arc-shaped, so it is inserted into the vertebral body and rotated so that the convex part of the TLIF cage faces ventrally. The TLIF cage is larger than the PLIF cage, but its supporting surface is smaller than that of the LLIF or ALIF cage, which will be mentioned later.

[0012] Anterior interbody fusion (ALIF) offers several advantages, including a quicker recovery and no need to worry about adhesions. However, it requires a highly skilled technique, as it requires an anterior (ventral) incision, removing internal organs, and approaching the spine. The ALIF cage boasts the largest support surface area of ​​all spinal fusion cages.

[0013] Lateral lumbar fusion (LLIF) was developed to overcome the shortcomings of ALIF, PLIF, and TLIF. Lateral lumbar fusion is performed through a flank incision, allowing for a wider space between the vertebrae compared to conventional back incision surgeries, with minimal damage to surrounding tissues. However, because the surgical path is surrounded by the psoas muscle and peritoneum, there are concerns that mistakes during the surgery may result in thigh muscle paralysis. The LLIF cage is smaller than the ALIF cage, but smaller than the PLIF or TLIF cages.

[0014] Compared to this lateral lumbar fusion, oblique lumbar interbody fusion (OLIF or anterior to psoas) fusion is a safer and more effective surgical method. OLI fusion is performed through a surgical route described from the side, and has the advantage of being possible between the L4 and L5 vertebrae, which are difficult to operate with DLIF, due to the psoas muscle and peritoneum. Furthermore, the risk of nerve damage, which is a problem in lateral lumbar fusion, is significantly lower.

[0015] However, the spinal fusion surgery described above makes the upper and lower vertebrae into one, so from the patient's perspective, one of the corresponding discs is missing, and the patient loses the amount of movement that the disc was responsible for.

[0016] To address this loss of mobility, the artificial disc was developed. The surgical procedure involves first removing the damaged intervertebral disc, creating a space between two adjacent vertebrae, and then inserting the artificial disc into this space. Because the upper and lower plates of the artificial disc allow for a certain range of motion, it offers the advantage of maintaining mobility even after surgery.

[0017] In conventional artificial disc replacement surgery, the posterior arch, which is composed of a pair of pedicles, the superior and inferior articular processes extending posteriorly from the pedicles, the lamina, and the supraspinous process, is located on the back, so the surgery was performed from the anterior approach after opening the abdomen, resecting the peritoneum, and lifting and moving the organs.

[0018] To explain in more detail, the patient is first placed face-up, and an incision is made in the anterior abdomen. The surgical path is secured to the spine, avoiding the internal organs. Then, a portion of the anterior longitudinal ligament (ALL) is incised on the anterior surface of the vertebral body. This incision exposes the intervertebral disc. This disc is removed using surgical instruments, and an artificial disc is inserted in its place.

[0019] Conventional artificial discs typically include an upper plate and a lower plate that contact the vertebral body, and an insert inserted between the upper and lower plates. However, prior art disclosed to date has the disadvantage of failing to accurately replicate the spinal movements of the human body, as it relies solely on spherical contact between the upper plate and the insert.

[0020] The present invention is intended to solve the above problems, and aims to provide an anteriorly inserted artificial disc that can be inserted from the anterior approach of a vertebral body, and that can implement human body movement while having a simple structure.

[0021] In order to achieve the above object, the present invention is an anteriorly inserted artificial disc, which is an artificial disc inserted between two adjacent vertebrae, comprising: an upper plate whose upper surface contacts the upper vertebrae; a lower plate whose upper surface contacts the lower vertebrae; and an inserter inserted between the upper plate and the lower plate, wherein the upper spherical surfaces of the upper plate and the inserter are in surface contact with each other to form a spherical surface, and the inserter rotates with respect to the lower plate about its major axis as a rotational center axis.

[0022] The inserter is characterized in that the upper plate slides within a predetermined angular range relative to the longitudinal axis, and the inserter slides within a predetermined angular range relative to a plane having the longitudinal axis as a normal line relative to the lower plate.

[0023] In addition, an upper limit groove is formed on the upper spherical surface, and an upper limit protrusion whose range of motion is limited by the upper limit groove is formed on an upper concave surface formed on the lower portion of the upper plate and in contact with the upper spherical surface.

[0024] In addition, the lower plate is characterized in that a lower groove is formed in which a lower swivel formed at the lower portion of the inserter is inserted, a lower limiting projection is formed on one side of the lower swivel and the lower groove, and a lower limiting groove is formed on the other side of the lower swivel and the lower groove to limit the range of motion of the lower limiting projection.

[0025] In addition, a swivel neck portion is formed protrudingly on the side of the lower swivel, a swivel fitting portion is formed on the lower portion of the swivel neck portion, a lower fixing jaw corresponding to the swivel neck portion is formed on the side of the lower groove, and a lower fitting portion into which the swivel fitting portion is inserted is formed under the lower portion of the lower fixing jaw.

[0026] In addition, it is characterized in that a lower free space is formed concavely around the lower limit protrusion.

[0027] In addition, the cross-sectional area of ​​the lower groove is larger than the cross-sectional area of ​​the lower swivel, so that the lower swivel is capable of moving within the lower groove.

[0028] According to an embodiment of the present invention configured as described above, it can be applied to the cervical or lumbar vertebrae because it is inserted into the front of the spine.

[0029] In addition, it is possible to provide an anteriorly inserted artificial disc that can implement human body movement while having a simple structure.

[0030] FIG. 1 is a perspective view of an artificial disc according to an embodiment of the present invention.

[0031] Figure 2 is a perspective view of the artificial disc of Figure 1, viewed from above, disassembled.

[0032] Figure 3 is a perspective view of the artificial disc of Figure 1, viewed from the bottom, disassembled.

[0033] Figure 4 is a drawing showing the artificial disc of Figure 1 being inserted into the vertebral body.

[0034] Figure 5 is a drawing showing the artificial disc of Figure 1 inserted into the vertebral body.

[0035] Hereinafter, the present invention will be described with reference to the accompanying drawings, which illustrate preferred embodiments thereof. When designating components in each of the drawings below, identical components will be given identical reference numerals, as much as possible, even if they appear in different drawings. Detailed descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted.

[0036] FIG. 1 illustrates an artificial disc (100) according to an embodiment of the present invention. First, directions are defined. The direction of the patient's abdomen is referred to as the Anterior Direction, and the direction of the patient's back is referred to as the Posterior Direction. Therefore, the Anterior Direction and the Posterior Direction are opposite directions. In addition, the patient's right side is referred to as the Right Direction, and the patient's left side is referred to as the Left Direction. In addition, the direction of the patient's head is referred to as the Superior Direction, and the direction of the patient's legs is referred to as the Inferior Direction.

[0037] And, the imaginary straight line defined in the forward and backward directions is called the Anterior to Posterior Axes, and the imaginary straight line defined in the right and left directions is called the Lateral Axis. Also, the imaginary straight line defined in the upward and downward directions is called the Vertical Axis. Therefore, the Anterior to Posterior Axes, the Horizontal Axis, and the Major Axis are perpendicular to each other.

[0038] Next, when defining a plane, the transverse plane is defined as a plane that has the long axis as the normal direction according to the definition in human anatomy, the frontal plane is defined as a plane that includes the long axis as the normal direction in the front-back direction of the human body, and the sagittal plane is defined as a plane that includes the long axis as the normal direction in the left-right direction of the human body.

[0039] The artificial disc (100) is inserted between two adjacent vertebrae, and basically includes an upper plate (102) whose upper surface contacts the upper vertebrae, a lower plate (104) whose upper surface contacts the lower vertebrae, and an inserter (106) inserted between the upper plate (102) and the lower plate (104) so ​​that the upper plate (102) rotates at a set angle with respect to the lower plate (104).

[0040] With respect to the inserter (106), the upper plate (102) slides within a predetermined angular range relative to the longitudinal axis, and the inserter (106) slides within a predetermined angular range relative to a plane having the longitudinal axis as a normal line relative to the lower plate (104).

[0041] The upper plate (102), the inserter (106), and the lower plate (104) may be made of materials that are harmless to the human body. Since the upper plate (102) and the lower plate (104) must be fixed by contacting the vertebral body, a polymer material such as PEEK (Poly-Ether-Ether-Ketone) or a metal material such as titanium or a titanium alloy is preferable. In particular, titanium or a titanium alloy is preferable because it has the characteristic of providing excellent osseointegration. In particular, the surface roughness may be increased by processing such as sanding, deposition, or coating to have a rough surface so as to be advantageous for osteogenesis, osteoconduction, and osteoinduction at the contact surface with the vertebral body, or it may be formed to include a porous structure by 3D printing.

[0042] Since the above inserter (106) slides while in contact with the upper plate (102) and the lower plate (104), a polymer material such as UHMWPE (Ultra High Molecular Weight Polyethylene) with excellent wear resistance or a metal material such as a cobalt chromium (Co-Cr) alloy can be used.

[0043] Each element of the artificial disc (100) is described in detail with reference to FIGS. 2 and 3.

[0044] The inserter body (170) of the inserter (106) has a cross-section that is approximately square or circular and has a thickness in the direction of the major axis. An upper spherical surface (172) is formed on the upper portion of the inserter body (170) to form a convex sphere as a part of a sphere. That is, the upper spherical surface (172) is formed to protrude in the head direction with respect to the inserter body (170). In addition, an upper limiting groove (174) is formed on the center of the upper portion of the upper spherical surface (172) to have a substantially circular groove.

[0045] In addition, a lower swivel (176) is formed protrudingly at the bottom of the inserter body (170). The leg-directed surface of the lower swivel (176) is flat. That is, the lower swivel (176) is formed protrudingly in the leg direction with respect to the inserter body (170), and the bottom surface of the lower swivel (176) is parallel to the cross-section.

[0046] The cross-sectional area of ​​the lower swivel (176) is formed to be smaller than the cross-sectional area of ​​the inserter body (170). The cross-sectional shape of the lower swivel (176) is approximately circular. In addition, a lower limiting protrusion (182) is formed to protrude in the left and right directions of the lower swivel (176).

[0047] The lower limit protrusion (182) and the lower swivel (176) are formed so as not to protrude outward from the side of the inserter body (170). In addition, a lower free space (184) is formed concavely at the portion where the lower limit protrusion (182) begins to protrude from the lower swivel (176). The lower free space (184) not only provides a space through which a cutter can pass when manufacturing the lower swivel (176) and the lower limit protrusion (182), but can also be utilized as a space through which foreign substances can escape when the artificial disc (100) is inserted into the human body.

[0048] On the side of the lower swivel (176), a swivel neck (180) and a swivel fitting (178) are continuously formed in the leg direction. The swivel neck (180) has a smaller cross-sectional area than the swivel fitting (178).

[0049] The upper plate (102) is roughly plate-shaped and has a thickness in the direction of the longitudinal axis. In addition, the cross-section of the upper plate (102) has a rectangular cross-section similar to the cross-sectional shape of a human body disc.

[0050] The upper plate (102) is composed of approximately six sides: a front portion (108) of the upper plate in the forward direction, a rear portion (110) of the upper plate in the rear direction, upper plate side portions (112) in the left and right directions, an outer surface (114) of the upper plate that comes into contact with the vertebrae, and an inner surface (116) of the upper plate opposite to the outer surface (114) of the upper plate.

[0051] The thickness of the upper plate (102) may be the same as the thickness of the front part (108) of the upper plate and the thickness of the rear part (110) of the upper plate, or the thickness of the front part (108) of the upper plate may be formed to be thicker than the thickness of the rear part (110) of the upper plate.

[0052] The lordosis angle of the disc in the human spine varies. Accordingly, by changing the thickness of the upper plate (102), the artificial disc (100) can have the lordosis angle of the disc not only at 0 degrees but also at various angles, thereby providing the lordosis angle that the disc to be operated on in the patient should have, thereby maintaining the overall curved shape of the spine.

[0053] On the inner surface (116) of the upper plate (102) positioned in the leg direction, an upper concave surface (122) that can be spherically opposed to the upper spherical surface (172) is formed as a concave spherical surface. In addition, an upper limiting protrusion (124) is formed at the center of the upper concave surface (122). The upper limiting protrusion (124) is inserted into the upper limiting groove (174). As a result, the upper plate (102) makes a spherical contact movement with respect to the inserter (106), but since the upper limiting protrusion (124) is inserted into the upper limiting groove (174), the angular range of the spherical contact movement of the upper plate (102) with respect to the inserter (106) is limited.

[0054] In order to improve the support force with respect to the vertebral body, a superior central protrusion (118) and a superior peripheral protrusion (120) are formed in the forward and backward direction on the outer surface (114) of the superior plate (102) that contacts the vertebral body. The superior central protrusion (118) and the superior peripheral protrusion (120) are wedge-shaped, and the direction of the wedge is arranged such that the inclined surface faces the backward direction so that the artificial disc (100) does not come off when inserted into the vertebral body.

[0055] And, an upper mechanism groove (126) is formed on the upper plate side (112) so that it can be gripped by an insertion mechanism (not shown). That is, the gripping portion (not shown) of the insertion mechanism can be inserted into the upper mechanism groove (126). And, an upper mechanism guide portion (128) is formed in the forward direction of the upper mechanism groove (126). The upper mechanism guide portion (128) is formed in a curved shape so that it is easy to detach the insertion mechanism from the artificial disc (100) when the artificial disc (100) is inserted into the vertebral body using the insertion mechanism.

[0056] The above lower plate (104) is roughly plate-shaped and has a thickness in the direction of the longitudinal axis. In addition, the cross-section of the lower plate (104) has a rectangular cross-section similar to the cross-sectional shape of a human body disc.

[0057] The above lower plate (104) is composed of approximately six sides, including a front portion (138) of the lower plate in the forward direction, a rear portion (140) of the lower plate in the rearward direction, left and right lower plate sides (142), an outer surface (144) of the lower plate that comes into contact with the vertebrae, and an inner surface (146) of the lower plate opposite to the outer surface (144) of the lower plate.

[0058] The thickness of the lower plate (104) may be the same as the thickness of the front part (138) of the lower plate and the thickness of the rear part (140) of the lower plate, or the thickness of the front part (138) of the lower plate may be formed to be thicker than the thickness of the rear part (140) of the lower plate.

[0059] The lordosis angle of the disc in the human spine varies. Accordingly, by varying the thickness of the lower plate (104), the artificial disc (100) can have a lordosis angle of the disc of various degrees, not just 0 degrees, thereby providing the lordosis angle that the disc to be operated on in the patient should have, thereby maintaining the overall curved shape of the spine.

[0060] A lower groove (152) into which the lower swivel (176) is inserted is formed on the inner surface (146) of the lower plate (104) positioned in the head direction.

[0061] The bottom surface of the lower groove (152) is flat and makes sliding contact with the bottom surface of the lower swivel (176). In addition, since the cross-sectional area of ​​the lower groove (152) is larger than that of the lower swivel (176), the lower swivel (176) can move within the lower groove (152).

[0062] A lower limit groove (158) is formed on the left and right sides of the lower groove (152). The lower limit groove (158) is a space into which the lower limit protrusion (182) is inserted, and has a size that allows the lower limit protrusion (182) to move at a certain angle.

[0063] In addition, a lower fitting part (156) and a lower fixing jaw (154) are formed on the side of the lower groove (152). The lower fitting part (156) corresponds to the swivel fitting part (178), and the lower fixing jaw (154) corresponds to the swivel neck part (180).

[0064] Accordingly, since the swivel fitting part (178) is inserted into the lower fitting part (156), the swivel neck part (180) is restrained by the lower fixing jaw (154), so the inserter (106) does not come off with respect to the lower plate (104).

[0065] In order to improve the support force with respect to the vertebral body, a lower central protrusion (148) and a lower peripheral protrusion (150) are formed in the forward and backward direction on the outer surface (144) of the lower plate (104) that contacts the vertebral body. The lower central protrusion (148) and the lower peripheral protrusion (150) are wedge-shaped, and the direction of the wedge is arranged such that the inclined surface faces the posterior direction so that the artificial disc (100) does not come off when inserted into the vertebral body.

[0066] And, a lower mechanism groove (160) is formed on the side of the lower plate (142) so that it can be gripped by an insertion mechanism (not shown). That is, the gripping portion (not shown) of the insertion mechanism can be inserted into the lower mechanism groove (160). And, a lower mechanism guide portion (162) is formed in the forward direction of the lower mechanism groove (160). The lower mechanism guide portion (162) is formed in a curved shape so that it is easy to detach the insertion mechanism from the artificial disc (100) when the artificial disc (100) is inserted into the vertebral body using the insertion mechanism.

[0067] The structure of the artificial disc (100) according to the present invention is as described above. Next, the movement of the artificial disc (100) will be described in detail.

[0068] As illustrated in FIGS. 4 and 5, the artificial disc (100) is inserted into the vertebral body (10) toward the posterior direction with the patient's front side open. At this time, the upper plate (102) and the lower plate (104) of the artificial disc (100) must be fixed to the vertebral body (10) while contact movement between the inserter (106) and the upper plate (102) and contact movement between the inserter (106) and the lower plate (104) must occur. Therefore, the upper plate (102) and the lower plate (104) need to be strongly fixed to the vertebral body (10).

[0069] Accordingly, the upper central protrusion (118) and the upper peripheral protrusion (120), and the lower central protrusion (148) and the lower peripheral protrusion (150) formed on the upper plate outer surface (102) of the upper plate (102) and the lower plate outer surface (302) of the lower plate (104) forcefully form grooves on the surface of the vertebral body when the artificial disc (100) is inserted into the vertebral body (10) and come into close contact with the vertebral body. Accordingly, not only does the surface area between the vertebral body and the upper plate (102) and the lower plate (104) increase, but also slipping can be prevented when a load is transmitted from the vertebral body to the upper plate (102) and the lower plate (104).

[0070] In the human body, discs function as ligaments that connect the vertebrae, serve as the center of spinal movement, and cushion spinal shock. Specifically, disc-mediated spinal movements include three types: flexion-extension motion, lateral bending, and axial rotation.

[0071] First, forward and backward flexion is a sagittal plane movement, bending the body forward or backward. Lateral bending is a frontal plane movement, tilting the body sideways. Axis rotation, also known as a twist, is a movement that rotates the torso while maintaining an upright posture.

[0072] The lower plate (104) and the inserter (106) are capable of rotational movement in a plane normal to the longitudinal axis, i.e., a cross-section. At this time, since the movement of the lower limiting projection (182) of the inserter (106) is limited by the lower limiting groove (158) of the lower plate (104), the inserter (106) is capable of rotational movement only within a certain angular range with respect to the inserter (106). However, since the cross-sectional area of ​​the lower groove (152) of the lower plate (104) is slightly larger than the cross-sectional area of ​​the lower swivel (176), the translational movement of the inserter (106) with respect to the lower plate (104) is also possible at the same time.

[0073] In addition, the upper plate (102) is capable of spherical contact motion with respect to the inserter (106). That is, since the upper plate (102) forms a spherical contact with the inserter (106), all of the spine's movements, such as flexion-extension motion, lateral bending, and axial rotation, by the disc are possible.

[0074] Since the movement of the human body is a complex combination of forward and backward flexion and extension, left and right bending, and axial rotation, when forward and backward flexion and axial rotation occur simultaneously, or when left and right bending and axial rotation occur simultaneously, the spherical contact motion of the upper plate (102) and the inserter (106) cannot implement such a complex motion. In this case, if the upper plate (102) and the inserter (106) are responsible for only forward and backward flexion or left and right bending, and the lower plate (104) and the inserter (106) perform axial rotation at the same time, the complex motion can be implemented.

[0075] In addition, when the upper plate (102) performs a forward bending motion with respect to the inserter (106), the artificial disc (100) is always subjected to a vertical load in the longitudinal direction, so the inserter (106) is pushed backward in the lower groove (152) of the lower plate (104). Accordingly, the forward bending motion of the upper plate (102) with respect to the inserter (106) can be performed more smoothly.

[0076] Conversely, when the upper plate (102) is bent backward with respect to the inserter (106), the inserter (106) is pushed forward in the lower groove (152) of the lower plate (104). Therefore, the backward bending movement of the upper plate (102) with respect to the inserter (106) can be performed more smoothly.

[0077] Likewise, when the upper plate (102) bends to the left with respect to the inserter (106), the inserter (106) is pushed to the right in the lower groove (152) of the lower plate (104). Therefore, the leftward bending movement of the upper plate (102) with respect to the inserter (106) can be performed more smoothly.

[0078] In addition, when the upper plate (102) bends to the right with respect to the inserter (106), the inserter (106) is pushed to the left in the lower groove (152) of the lower plate (104). Therefore, the rightward bending movement of the upper plate (102) with respect to the inserter (106) can be performed more smoothly.

[0079] As these forward and backward bending, left and right bending, and axial rotation occur in a complex manner, the artificial disc (100) can move similarly to the movement of a disc in the human body.

[0080] As described above, although the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the present invention can be variously modified and changed within the scope and spirit of the present invention as set forth in the claims below.

[0081] Therefore, the artificial disc according to the present invention is expected to be able to replace the existing artificial disc because it can overcome the problems and disadvantages of the conventional anteriorly inserted artificial disc and maintain the patient's mobility.

[0082] <Description of drawing symbols>

[0083] 10: Vertebra 100: Artificial disc

[0084] 102: Upper plate 104: Lower plate

[0085] 106: Inserter 108: Front of upper plate

[0086] 110: Rear of upper plate 112: Side of upper plate

[0087] 114: Upper plate outer surface 116: Upper plate inner surface

[0088] 118: Upper central process 120: Upper peripheral process

[0089] 122: Upper concave surface 124: Upper limit projection

[0090] 126: Upper mechanism home 128: Upper mechanism guide section

[0091] 138: Front of lower plate 140: Rear of lower plate

[0092] 142: Lower plate side 144: Lower plate outer surface

[0093] 146: Inner surface of lower plate 148: Lower center protrusion

[0094] 150: Lower peripheral protrusion 152: Lower groove

[0095] 154: Lower fixing jaw 156: Lower fitting part

[0096] 158: Lower limit home 160: Lower mechanism home

[0097] 162: Lower mechanism guide 170: Inserter body

[0098] 172: Upper spherical surface 174: Upper limit groove

[0099] 176: Lower swivel 178: Swivel fitting

[0100] 180: Swivel neck 182: Lower limit protrusion

[0101] 184: Lower spare part

Claims

1. For an artificial disc inserted between two adjacent vertebrae, The upper plate, whose upper surface is in contact with the upper vertebra; A lower plate whose upper surface contacts the lower vertebra; and Including an inserter inserted between the upper plate and the lower plate, The upper spherical surface of the upper plate and the upper spherical surface of the inserter are in surface contact with each other to form a spherical surface. An anteriorly inserted artificial disc, characterized in that the inserter performs a rotational movement with the longitudinal axis as the center of rotation axis with respect to the lower plate.

2. In paragraph 1, An anterior insertable artificial disc, characterized in that the upper plate slides within a predetermined angular range with respect to the longitudinal axis with respect to the inserter, and the inserter slides within a predetermined angular range with respect to a plane having the longitudinal axis as a normal line with respect to the lower plate.

3. In paragraph 2, An anterior insertable artificial disc characterized in that an upper limiting groove is formed on the upper spherical surface, and an upper limiting protrusion is formed on an upper concave surface formed on the lower portion of the upper plate and in contact with the upper spherical surface, the range of motion of which is limited by the upper limiting groove.

4. In paragraph 3, The lower plate has a lower groove formed into which a lower swivel formed at the lower portion of the inserter is inserted. An anteriorly inserted artificial disc characterized in that a lower limiting projection is formed on one of the lower swivel and the lower groove, and a lower limiting groove that limits the range of motion of the lower limiting projection is formed on the other of the lower swivel and the lower groove.

5. In paragraph 4, An anterior insertion type artificial disc characterized in that a swivel neck portion is protrudedly formed on the side of the lower swivel, a swivel fitting portion is formed on the lower portion of the swivel neck portion, a lower fixing jaw corresponding to the swivel neck portion is formed on the side of the lower groove, and a lower fitting portion into which the swivel fitting portion is inserted is formed under the lower portion of the lower fixing jaw.

6. In paragraph 4, An anteriorly inserted artificial disc characterized in that a lower free space is formed concavely around the lower limiting protrusion.

7. In paragraph 4, An anteriorly inserted artificial disc, characterized in that the cross-sectional area of ​​the lower groove is larger than the cross-sectional area of ​​the lower swivel, so that the lower swivel can move within the lower groove.

Images