Artificial lumbar intervertebral disc

Abstract

The present invention provides a side-entry artificial lumbar intervertebral disc which is inserted into the side of the spinal column rather than the anterior of the spinal column, and thus relates to an artificial lumbar intervertebral disc which prevents the occurrence of damage to blood vessels or other organs which may be caused by a front-entry artificial intervertebral disc inserted from the front, can shorten the operation time, and can improve the operation efficiency. Dislocation of the artificial intervertebral disc can be prevented, and even operation prognosis can be improved. An artificial intervertebral disc is inserted between two adjacent vertebrae and includes: an upper plate in contact with an upper vertebra; a lower plate in contact with the lower vertebra; and an insert inserted between the upper plate and the lower plate such that the upper plate is rotatable by a set angle relative to the lower plate, in which each of the upper plate and the lower plate has an upper wing portion and a lower wing portion extending in an insertion direction and an apparatus direction when the insert is inserted.

Description

Technical Field

[0001] The present disclosure relates to an artificial lumbar intervertebral disc, and more particularly, to an artificial lumbar intervertebral disc that can be inserted into a vertebral body from a lateral direction. Background Art

[0002] The spine is composed of 32 to 35 vertebrae that make up the torso and the intervertebral plates or discs between the vertebrae, and is the central part of the body, connecting the skull at the top and the pelvis at the bottom.

[0003] The vertebrae include 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae, and 3 to 5 coccygeal vertebrae from the top. In an adult, 5 sacral vertebrae are fused to form 1 sacrum, and 3 to 5 coccygeal vertebrae are fused to form 1 coccyx.

[0004] Between the vertebrae, there is a cartilaginous substance called an intervertebral disc. The cartilaginous substance is a soft and flexible fibrous cartilage that forms cartilaginous joints, helps the spine to move flexibly and stabilize the spine like a ligament, and absorbs and reduces the impact applied to the vertebral body. The intervertebral disc is composed of a fibrous disc with a fibrous outer part and a core with a gel-like substance inside, which helps maintain strength and disperse stress. In other words, the intervertebral disc absorbs the load of the body and the impact between each vertebra except some cervical vertebrae, acts as a buffer that disperses the impact like a spring, holds the vertebrae so that they do not move apart, firmly provides a smooth range of spinal joint space by separating two vertebrae so that the spinal nerves are not compressed, and plays a role in facilitating the movement of each vertebra.

[0005] Since the intervertebral disc buffers or transfers loads and impacts applied in the vertical direction, various diseases such as spinal canal stenosis, osteophyte formation, intervertebral disc herniation, and nerve root compression may occur.

[0006] Spinal fusion has been used for a long time as a method of treatment for serious spinal diseases. Spinal fusion is a surgical procedure in which an intervertebral disc is removed and a fusion cage is inserted to replace the intervertebral disc so that adjacent vertebrae are fused.

[0007] When spinal fusion is performed on the lumbar spine, spinal fusion can be divided into posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), lateral lumbar interbody fusion (LLIF), oblique lumbar interbody fusion (OLIF), and anterior lumbar interbody fusion (ALIF) based on the direction of cage insertion.

[0008] In PLIF, an incision is made along the midline of the spine, the incision is partially opened to expose the entire vertebral body, a portion of the back of the vertebra is removed, the disc is removed, and the PLIF cage is inserted.

[0009] PLIF is the oldest spinal fusion technique and is an important method when performing a two-joint or three-joint fusion. Due to the surgical procedure, there is a high possibility of adhesions to nerves, ligaments, and muscles, and due to the large incision area, the healing time is long and some people have significant sequelae.

[0010] The PLIF cage consists of a pair of small cages placed on either side of the spine and is the smallest cage used in all spinal fusions.

[0011] TLIF is a surgical method in which small incisions are made along both sides of the spinal muscles, the vertebral bodies are minimally exposed, and the TLIF fusion device is inserted while the spinal joint area is removed in the direction of the interconal foramen. This surgical technique has the advantages of reducing bleeding and shortening the operation time, so it is suitable for single joint surgery, but when multiple areas require surgery, PLIF surgery is required. The TLIF fusion device is mostly arc-shaped, and therefore, the TLIF fusion device is inserted into the spine and rotated so that the convex part of the TLIF fusion device faces the ventral side. The TLIF fusion device is larger than the PLIF fusion device, but the support area of ​​the TLIF fusion device is smaller than that of the LLIF fusion device or the ALIF fusion device, which will be mentioned later.

[0012] ALIF has many advantages, such as quick recovery from surgery and no need to worry about adhesions, but because ALIF is performed by making an incision in the anteroventral side to remove the internal organs and access the spine, its disadvantage is that it requires highly skilled techniques. The ALIF cage has the advantage of having the largest support area of ​​all spinal fusion cages.

[0013] LLIF was developed to overcome the shortcomings of ALIF, PLIF, and TLIF. Because LLIF is performed through an incision on the side, the LLIF approach can widen the gap in the narrow area between vertebrae and has the advantage of causing less damage to surrounding tissues compared to existing surgeries involving an incision on the back. However, because the surgical path is surrounded by the psoas muscle and peritoneum, problems such as thigh muscle paralysis can occur if mistakes are made during the operation. The LLIF cage is smaller than the ALIF cage, but larger than the PLIF or TLIF cage.

[0014] OLIF or anterior psoas fusion (ATP) is a safer and more effective surgical approach compared to LLIF. OLIF has the advantage of allowing the surgical approach to be formed from the side in an oblique direction and can be performed between the 4th lumbar vertebra L4 and the 5th lumbar vertebra L5, which are difficult to operate on with DLIF due to the psoas muscle and peritoneum. In addition, the possibility of damaging the nerves (which may be difficult to address in LLIF) is significantly reduced.

[0015] However, since the above-mentioned spinal fusion forms the upper vertebra and the lower vertebra into one vertebra, and therefore, from the patient's perspective, one of the corresponding intervertebral discs is missing, thereby losing the range of motion for which the intervertebral disc is responsible.

[0016] Artificial intervertebral discs have been developed to solve the problem of loss of mobility. In a surgical method using an artificial intervertebral disc, a damaged intervertebral disc is first removed, a gap is created between two adjacent vertebrae, and then an artificial intervertebral disc is inserted into the gap. An artificial intervertebral disc has the advantage of maintaining mobility even after surgery because the upper and lower plates can move within a certain range of angles.

[0017] In conventional artificial disc replacement surgery, since the posterior arch (composed of a pair of pedicles, superior and inferior articular processes extending posteriorly from the pedicles, the lamina propria, and the supraspinatus muscle) is located on the dorsal side, the surgery is performed from the front approach after opening the abdomen, removing the peritoneum, and mobilizing the organs.

[0018] In more detail, among them, first, the patient lies in a front-up manner, the abdomen of the body is cut from the front, and the surgical path is fixed to the spine to avoid the organs. Then, a part of the anterior longitudinal ligament is cut on the front side of the spine. When the anterior longitudinal ligament is cut, the intervertebral disc between the vertebrae is exposed. The intervertebral disc is removed using surgical instruments, and an artificial intervertebral disc is inserted to replace the intervertebral disc.

[0019] Therefore, conventional surgical methods using artificial intervertebral discs have problems such as large incision area, the need to perform surgery while avoiding organs (therefore there is a possibility of damaging surrounding blood vessels and tissues), and increased surgical time. In particular, since the anterior longitudinal ligament is cut, there is a more serious problem of poor postoperative prognosis for patients.

[0020] Another problem caused by the incision of the anterior longitudinal ligament is that although the original human intervertebral disc is blocked by the anterior longitudinal ligament, if an artificial intervertebral disc is inserted with the anterior longitudinal ligament cut, when a load is applied in the long axis direction of the human body, the force is transmitted forward, which may cause the artificial intervertebral disc to fall off in the anterior direction.

[0021] Additionally, due to the removal of the anterior longitudinal ligament, there is a problem of excessive force being transmitted to the posterior joint, which may cause other spinal deformities. Summary of the invention

[0022] Technical issues

[0023] The present disclosure aims to solve the above-mentioned problems and provide a side-entry artificial intervertebral disc, which is inserted into the spine laterally rather than anteriorly, thereby preventing damage to blood vessels or other organs that may be caused by an anterior-entry artificial intervertebral disc inserted from the front, shortening the operation time, preventing dislocation of the artificial intervertebral disc, and improving the surgical prognosis.

[0024] Technical Solution

[0025] In an artificial intervertebral disc inserted between two adjacent vertebrae, according to the present disclosure, the artificial intervertebral disc includes: an upper plate in contact with the upper vertebra; a lower plate in contact with the lower vertebra; and an insert inserted between the upper plate and the lower plate to allow the upper plate to rotate a set angle relative to the lower plate, wherein the upper plate and the lower plate have upper and lower wing portions formed along a lateral axis when the insert is inserted.

[0026] The thickness of the upper plate and the lower plate in the front direction may be greater than the thickness in the rear direction.

[0027] An upper ridge portion and a lower ridge portion may be formed on an upper plate outer surface of the upper plate and a lower plate outer surface of the lower plate along the lateral axis, respectively.

[0028] A plurality of upper protrusions and a plurality of lower protrusions may be formed on an upper plate outer surface of the upper plate and a lower plate outer surface of the lower plate, respectively.

[0029] The plurality of upper protrusions and the plurality of lower protrusions may have a quadrangular pyramid shape having a quadrangular cross-section including four line segments each perpendicular to the lateral axis and the front-rear axis.

[0030] The insert may include an upper dome portion located on the upper side of the insert and a first axial rotation portion located on the lower side of the insert, an upper groove corresponding to the upper dome portion may be formed on the upper plate and may be in sliding contact with the upper dome portion, and a second axial rotation portion in contact with the first axial rotation portion may be formed on the lower plate.

[0031] The upper dome portion can be formed into an elliptical hemispherical shape, the major axis of which is arranged on the lateral axis and the minor axis is arranged on the anterior-posterior axis, and by moving the upper dome portion and the upper groove in contact with each other, the upper plate can perform lateral bending and anterior-posterior flexion and extension movements relative to the lower plate.

[0032] The maximum depth of the upper groove may be formed to be smaller than the maximum height of the upper dome portion.

[0033] An upper stopper may be formed around the upper groove, and the angular momentum of the upper plate may be limited by contact of the upper stopper with an insert upper surface of the insert body formed around the upper dome portion.

[0034] The insert lower surface of the insert body may be formed to be flat, and the insert upper surface may be formed such that a thickness of the insert upper surface gradually decreases from the upper dome portion to an end of the insert body.

[0035] The first axial rotation portion may be a lower outer protrusion formed on the lower surface of the insert, and the second axial rotation portion may be a lower outer groove formed on the lower plate, and the lower outer groove may be formed in an arc shape, wherein the lower outer groove may be formed in an arc shape.

[0036] A lower center protrusion may be formed at the center of a lower surface of the insert, and a lower center groove corresponding to the lower center protrusion may be formed on the lower plate.

[0037] Technical Effects

[0038] According to the embodiment of the present disclosure configured as described above, there is provided an artificial lumbar intervertebral disc that allows lateral insertion into the spine, and thus can prevent damage to blood vessels or other organs during surgery and shorten surgery time.

[0039] Furthermore, if such an artificial intervertebral disc is inserted, the anterior longitudinal ligament is not removed, and therefore, there are advantages that postoperative dislocation of the artificial intervertebral disc can be prevented and the function of the anterior longitudinal ligament can be maintained as it is.

[0040] In addition, since the artificial lumbar intervertebral disc is inserted laterally, it not only has the advantage of preventing damage to the organ, but also has the advantage of shortening the operation time, thereby suppressing the amount of bleeding during the patient's operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a perspective view of an artificial intervertebral disc according to an embodiment of the present disclosure.

[0042] Figure 2 Viewed from the insertion direction Figure 1 Side view of an artificial disc.

[0043] Figure 3 Observed from the top Figure 1 Exploded perspective view of an artificial intervertebral disc.

[0044] Figure 4 Observed from the bottom Figure 1 Exploded perspective view of an artificial intervertebral disc.

[0045] Figure 5 Viewed from the insertion direction Figure 1 View of the insert of an artificial intervertebral disc.

[0046] Figure 6 Observed from the front Figure 1 View of the insert of an artificial intervertebral disc.

[0047] Figure 7 It is used to explain Figure 1A diagram of the manner in which lateral bending and anterior-posterior flexion-extension movements of an artificial intervertebral disc insert are achieved.

[0048] Figure 8 It is used to explain Figure 1 FIG. 1 is a diagram of a method for achieving axial rotation of an insert of an artificial intervertebral disc.

[0049] Fig. 9 It shows that Figure 1 Diagram of an artificial intervertebral disc inserted into a vertebral body.

[0050] Fig.10 is shown inserted into the vertebral body Figure 1 Diagram of an artificial intervertebral disc. DETAILED DESCRIPTION

[0051] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. When assigning reference numerals to components of the following drawings, the same reference numerals are assigned to the same components as much as possible even if the same components are shown in different drawings, and detailed descriptions of known functions and configurations that may unnecessarily make the subject matter of the present disclosure unclear are omitted.

[0052] Figure 1 An artificial intervertebral disc 10 according to an embodiment of the present disclosure is shown. First, directions are defined. The direction of the abdomen of the patient is referred to as the front direction, and the direction of the back of the patient is referred to as the rear direction. Therefore, the front direction and the rear direction are opposite. In addition, the direction in which the artificial intervertebral disc 10 is inserted during surgery is referred to as the insertion direction, and the direction in the opposite direction of the insertion direction (the direction in which the device (not shown) for holding the artificial intervertebral disc 10 is located) is referred to as the installation direction.

[0053] In addition, an imaginary straight line determined along the front and rear directions is referred to as an anterior-posterior axis, and an imaginary straight line determined along the installation direction and the insertion direction is referred to as a lateral axis. In addition, the height direction of the human body is referred to as a vertical axis. Therefore, the anterior-posterior axis, the lateral axis, and the vertical axis may be formed to be perpendicular to each other.

[0054] Next, if a plane is defined, according to the definition in human anatomy, the plane is defined as a transverse plane with the vertical axis as the normal direction, a coronal plane including the vertical axis and with the anterior-posterior direction of the human body as the normal direction, and a sagittal plane including the vertical axis and with the left-right direction of the human body as the normal direction.

[0055] The artificial intervertebral disc 10 includes: an upper plate 100, the outer surface of which is substantially in contact with the upper vertebra to be inserted between two adjacent vertebrae; a lower plate 300, the outer surface of which is in contact with the lower vertebra; and an insert 200, which is inserted between the upper plate 100 and the lower plate 300 so that the upper plate 100 can rotate at a set angle relative to the lower plate 300.

[0056] The upper plate 100, the insert 200 and the lower plate 300 may include materials that are harmless to the human body. Because the upper plate 100 and the lower plate 300 need to be fixed by contacting the vertebral body, polymer materials (such as polyetheretherketone (PEEK)) or metal materials (such as titanium or titanium alloys) are preferred. Specifically, titanium or titanium alloys are preferred because they have the property of providing excellent bone bonding. Specifically, in order to facilitate osteogenesis, osteoconduction and osteoinduction, the roughness of the surface can be increased by grinding, deposition, coating, etc., so that the contact surface with the vertebral body has a rough surface, or the surface can be formed to include a porous structure by 3D printing.

[0057] Since the insert 200 slides while contacting the upper plate 100 and the lower plate 300 , a polymer material such as ultra high molecular weight polyethylene (UHMWPE) having excellent wear resistance or a metal material such as cobalt chromium (Co—Cr) alloy may be used.

[0058] like Fig. 9 and Fig.10 As shown, since the artificial intervertebral disc 10 is inserted from the lateral direction of the patient, the artificial intervertebral disc 10 should be adjusted to have a width along the anterior-posterior axis of the vertebra 20 that is shorter than the left-right length along the lateral axis of the vertebra 20. In addition, since the surgery is performed in the lateral direction, a minimally invasive surgery (MIS) with a long and narrow surgical path is performed. Therefore, the artificial intervertebral disc 10 has an approximately rectangular shape, which is long in the lateral axis direction and short in the anterior-posterior axis direction.

[0059] Therefore, when the insert 200 is inserted between the upper plate 100 and the lower plate 300, the upper wing portion 101 and the lower wing portion 301 extending along the lateral axis are formed in the upper plate 100 and the lower plate 300. That is, the upper plate 100 and the lower plate 300 extend to the outside of the width of the insert 200 in the lateral axis direction in the length direction, and therefore, the upper plate 100 and the lower plate 300 have an approximately rectangular shape, which is long in the length in the lateral axis direction and narrow in the length in the front-rear axis direction.

[0060] As described below, due to the shape of the insert 200, the upper plate 100 and the lower plate 300 of the artificial intervertebral disc 10 are bent left and right in the coronal plane relative to the insert 200. At this time, if the insert 200 has the same length as the upper plate 100 or the lower plate 300, the movement amount of the upper plate 100 and the lower plate 300 during the left and right bending is limited due to the thickness of the insert 200. Therefore, by forming the upper wing portion 101 and the lower wing portion 301 and relatively reducing the length of the insert 200 in the lateral axis direction, there is an advantage that the size of the left and right bending of the artificial intervertebral disc 10 can be increased.

[0061] like Figure 3 and Figure 4 As shown, the upper plate 100 is composed of an upper anterior wall portion 110 in the anterior direction, an upper posterior wall portion 112 in the posterior direction, an upper device wall portion 106 in the device direction, an upper insertion wall portion 108 in the insertion direction, an upper plate outer surface 102 in contact with the vertebrae, and an upper plate inner surface 104 in the opposite direction of the upper plate outer surface 102, forming an approximate hexahedron.

[0062] Similarly, the lower plate 300 is composed of a lower anterior wall portion 310 in the anterior direction, a lower posterior wall portion 312 in the posterior direction, a lower device wall portion 306 in the device direction, a lower insertion wall portion 308 in the insertion direction, a lower plate outer surface 302 in contact with the vertebrae, and a lower plate inner surface 304 in the opposite direction of the lower plate outer surface 302, forming an approximate hexahedron.

[0063] In the lumbar vertebrae of the human body, the lordotic angle of the intervertebral disc increases from the intervertebral disc closer to the thoracic vertebrae to the intervertebral disc closer to the sacrum.

[0064] In the artificial intervertebral disc 10, in order to correspond to the lordotic angle of the intervertebral disc, the upper plate 100 and the lower plate 300 are shaped so that the thickness in the anterior direction is greater than the thickness in the posterior direction. Figure 2 As shown, the upper plate outer surface 102 of the upper plate 100 and the lower plate outer surface 302 of the lower plate 300 may be formed to be inclined to each other.

[0065] In this case, the upper plate inner surface 104 of the upper plate 100 and the lower plate inner surface 304 of the lower plate 300 remain parallel to each other.

[0066] As a result, the artificial intervertebral disc 10 allows the lordosis angle of the intervertebral disc to vary, rather than just 0 degrees, thereby allowing the lordosis angle of the intervertebral disc of the patient to have an appropriate value after surgery. Therefore, the artificial intervertebral disc 10 can maintain the overall curvature of the lumbar spine.

[0067] like Fig. 9 and Fig.10 As shown, the artificial intervertebral disc 10 is inserted between the vertebral bodies from the lateral direction of the patient. When the artificial intervertebral disc 10 is inserted, a strong impact is applied. In the artificial intervertebral disc 10, in a state where the upper plate 100 and the lower plate 300 are fixed to the vertebral body 20, the contact movement of the insert 200 with the upper plate 100 and the contact movement of the insert 200 with the lower plate 300 should occur. Therefore, it is necessary to firmly fix the upper plate 100 and the lower plate 300 to the vertebral body 20.

[0068] Therefore, an upper ridge portion 114 and a lower ridge portion 314 may be formed along the lateral axis on the upper plate outer surface 102 of the upper plate 100 and the lower plate outer surface 302 of the lower plate 300, respectively. Thus, when the artificial intervertebral disc 10 is inserted into the vertebral body 20 so that the artificial intervertebral disc is in close contact with the vertebral body, the upper ridge portion 114 and the lower ridge portion 314 forcefully form a groove on the surface of the vertebral body. Therefore, not only the surface area between the vertebral body and the upper plate 100 and the lower plate 300 is increased, but also when the load is transferred from the vertebral body to the upper plate 100 and the lower plate 300, slippage can be prevented.

[0069] In addition, if Figure 3 and Figure 4 As shown, a plurality of upper protrusions 116 and a plurality of lower protrusions 316 may be formed on the upper plate outer surface 102 of the upper plate 100 and the lower plate outer surface 302 of the lower plate 300 .

[0070] The upper protrusion 116 and the lower protrusion 316 may have a quadrangular pyramid shape having a rectangular cross section consisting of four line segments each of which is perpendicular to the lateral axis and the anterior-posterior axis. As a result, the upper protrusion 116 and the lower protrusion 316 may support loads in the direction along the lateral axis and in the direction along the anterior-posterior axis, thereby supporting the artificial intervertebral disc 10 in multiple directions.

[0071] Next, the insert 200 will be described.

[0072] In the human body, the intervertebral disc acts as a ligament connecting the vertebrae, acts as the movement center of the spine, and cushions the impact of the spine. Specifically, the spinal motion caused by the intervertebral disc is divided into three types: forward and backward flexion and extension, lateral bending, and axial rotation.

[0073] First, the forward and backward flexion movement is a movement performed in the sagittal plane and is a movement in which the body bends forward or backward. Lateral bending is a movement performed in the frontal plane and is a movement in which the body tilts left and right. Axial rotation is a movement called a twisting movement and is a movement in which the trunk twists and rotates while maintaining a straight state.

[0074] The main feature of the insert 200 is to separate and disperse the above three movements. That is, the upper dome portion 202 arranged on the upper side of the insert 200 is responsible for front and rear flexion and lateral bending, and the first axial rotation portion arranged on the lower side of the insert 200 is formed to be responsible for axial rotation. The upper dome portion 202 is in sliding contact with the upper groove 120 formed in the upper plate 100, and the first axial rotation portion is in sliding contact with the second axial rotation portion formed in the lower plate 300.

[0075] To this end, an upper dome portion 202 is formed on an upper side of the insert 200 , and a first axial rotation portion is formed on a lower side of the insert 200 .

[0076] like Figures 5 to 7 As shown, the upper dome portion 202 is formed in an elliptical hemispherical shape, the major axis of which is arranged on the lateral axis, and the minor axis of which is arranged on the anterior-posterior axis.

[0077] First, refer to Figure 5 , the upper dome portion 202 is formed to bend forward and backward along the front-back axis. Figure 6 , the upper dome portion 202 is formed to bend left and right along the lateral axis.

[0078] Therefore, by combining these two curved surfaces, the upper dome portion 202 is formed as shown in FIG. Figure 7 The elliptical hemispherical shape shown.

[0079] In addition, if Figure 3 As shown, in the upper plate 100, the upper groove 120 is formed to correspond to the upper dome portion 202 to slide in contact with the upper dome portion 202. That is, the upper groove 120 also has a curvature corresponding to a curvature formed front-to-back along the front-to-back axis of the upper dome portion 202 and a curvature corresponding to a curvature formed left-to-right along the lateral axis of the upper dome portion 202. Specifically, the maximum depth of the upper groove 120 is formed to be smaller than the maximum height of the upper dome portion 202, and therefore, the upper groove 120 may contact only a portion of the upper dome portion 202.

[0080] An insert body 204 is formed around the lower side of the upper dome portion 202. The insert body 204 is widely spread out in a flange, and in the embodiment of the present disclosure, the insert body is formed in an approximately square or rectangular shape, but may also be formed in an elliptical shape.

[0081] The insert lower surface 210 of the insert body 204 is formed flat to slide in contact with the lower plate inner surface 304 of the lower plate 300. Because of the sliding contact with the lower plate inner surface 304, the load applied to the upper plate 100 can be stably transferred to the lower plate 300 through the insert 200.

[0082] Furthermore, the insert lower surface 210 of the insert body 204 is formed such that the insert upper surface 206 has a thickness that gradually decreases from the upper dome portion 202 to the end of the insert body 204 when in a flat state. Figure 5 and Figure 6 By looking at the insert body 204 in FIG. 1 , it can be confirmed that the thickness of the insert upper surface 206 gradually decreases along the lateral axis and the anterior-posterior axis.

[0083] An upper stopper 118 is formed around the upper groove 120. The upper stopper 118 is formed to protrude from the upper plate inner surface 104.

[0084] The angular momentum of the upper plate 100 relative to the lower plate 300 is limited by the upper stop 118 contacting the insert upper surface 206 of the insert body 204 .

[0085] Specifically, by forming the insert upper surface 206 to have a thickness that gradually decreases from the upper dome portion 202 to the end of the insert body 204, the angular momentum of the upper plate 100 relative to the lower plate 300 can be increased. That is, compared with the insert upper surface 206 having a constant thickness, the thickness of the insert upper surface 206 gradually decreases toward the end of the insert body 204, which can further increase the tilt angle formed by the upper plate 100 and the lower plate 300 when the upper stopper 118 contacts the insert upper surface 206.

[0086] According to the embodiments of the present disclosure, Figure 4 As shown, the first axial rotation portion arranged on the lower side of the insert 200 is a lower outer protrusion 208 formed on the insert lower surface 210 of the insert body 204, and the second axial rotation portion is a lower outer groove 320 formed on the lower plate 300, and the lower outer groove 320 is formed in an arc shape.

[0087] The lower outer protrusions 208 are arranged symmetrically with respect to the center of rotation along the vertical axis of the insert 200. If there are more than three lower outer protrusions 208, they may be arranged at an angle with respect to the center of rotation along the vertical axis.

[0088] In one embodiment of the present disclosure, the lower outer protrusion 208 is formed into an approximately hemispherical shape, and the lower outer groove 320 is formed into an arc shape, so that the lower outer protrusion 208 moves within a certain angle range, and specifically, the end of the lower outer groove 320 has a shape on which the lower outer protrusion 208 can sit.

[0089] As another example of the first axial rotation portion, an arc-shaped groove or hole may also be formed in the insert body 204 , and a protrusion may be formed on the lower plate inner surface 304 of the lower plate 300 .

[0090] In addition, a lower center protrusion 212 may be formed at the rotation center of the insert lower surface 210 of the insert 200 along the vertical axis, and a lower center groove 318 corresponding to the lower center protrusion 212 may be formed on the lower plate 300. Conversely, a groove may be formed at the rotation center along the vertical axis of the insert lower surface 210, and a protrusion corresponding to the groove may be formed on the lower plate 300.

[0091] By combining the lower center protrusion 212 and the lower center groove 318, not only can the insert 200 rotate stably relative to the lower plate 300, but it also has the following advantages: it can stably support the load applied in the lateral axis or the front-back axis direction relative to the insert 200 or in any direction in the cross section.

[0092] The structure of the artificial intervertebral disc 10 according to the present disclosure is as described above. Next, the movement of the artificial intervertebral disc 10 will be described in detail.

[0093] The artificial intervertebral disc 10 can perform lateral bending and forward and backward flexion and extension movements of the upper plate 100 relative to the lower plate 300 by bringing the upper dome 202 of the insert 200 into contact with the upper groove 120 of the upper plate 100 to move.

[0094] That is to say, Figure 7 As shown, when the upper wing 101 of the upper plate 100 approaches the lower wing 301 of the lower plate 300 in the installation direction when the upper groove 120 is in contact with the upper dome 202, or when the upper wing 101 of the upper plate 100 approaches the lower wing 301 of the lower plate 300 in the insertion direction when the upper groove 120 is in contact with the upper dome 202, the upper plate 100 undergoes lateral bending in the coronal plane relative to the lower plate.

[0095] In addition, when the upper front wall portion 110 of the upper plate 100 approaches the lower front wall portion 310 of the lower plate 300 in the front direction in a state in which the upper groove 120 contacts the upper dome 202 and moves forward, or when the upper rear wall portion 112 of the upper plate 100 approaches the lower rear wall portion 312 of the lower plate 300 in a rear direction in a state in which the upper groove 120 contacts the upper dome 202 and moves backward, the upper plate 100 undergoes anterior-posterior flexion and extension movement relative to the lower plate in the sagittal plane.

[0096] At this time, the upper stop 118 surrounding the upper groove 120 contacts the insert upper surface 206 of the insert body 204, thereby limiting the amount of lateral bending and anterior-posterior flexion and extension movement.

[0097] In addition, if Figure 8 As shown, when the lower center protrusion 212 of the insert 200 is inserted into the lower center groove 318 of the lower plate 300, the axial rotation of the upper plate 100 relative to the lower plate 300 in the cross section can be achieved by moving the lower outer protrusion 208 of the insert 200 along the lower outer groove 320 of the lower plate 300.

[0098] At this time, when the lower outer protrusion 208 contacts both ends of the lower outer groove 320, the movement amount of the axial rotation is limited.

[0099] When such a combination of anterior-posterior flexion and extension motion, lateral bending, and axial rotation occurs, the artificial intervertebral disc 10 can move similar to the movement of a human intervertebral disc.

[0100] According to the artificial intervertebral disc 10 according to the present disclosure, artificial intervertebral disc replacement (ADR) can be performed by inserting the artificial intervertebral disc 10 from a side-entry method, and because the operation is performed by inserting the artificial intervertebral disc 10 from a side-entry method, the anterior longitudinal ligament and the posterior longitudinal ligament (PLT) that stabilize the spine during the operation can be preserved, and therefore, the force transmitted to the posterior joint can be reduced, thereby maintaining the spine more stably.

[0101] In addition, the anterior longitudinal ligament is the ligament that plays the most important role in preventing excessive curvature of the spine and maintaining the stability of the intervertebral joints. Therefore, if the anterior longitudinal ligament is cut, the spine will rotate beyond the original rotation range due to the loss of the anterior longitudinal ligament, and as a result, strain will be generated on the posterior joints. The present disclosure can solve the problems of conventional anterior approach artificial disc insertion surgery by retaining the anterior longitudinal ligament.

[0102] Furthermore, according to the artificial intervertebral disc 10, since motion control can be performed while retaining the anterior longitudinal ligament and the posterior longitudinal ligament, not only can the burden on the posterior joint be reduced, but also since the motion is controlled with the help of the anterior longitudinal ligament and the posterior longitudinal ligament, the motion can be optimized.

[0103] As described above, while the present disclosure has been described with reference to the preferred embodiments thereof, it will be appreciated by those skilled in the art that various modifications and changes may be made to the present disclosure within the spirit and scope of the present disclosure as set forth in the appended claims.

[0104] Industrial Applicability

[0105] In the case of inserting the artificial intervertebral disc forward, the help of a thoracic surgeon or a vascular surgeon is required to secure the incision and surgical path. However, in the case of inserting the spinal implant laterally, there is an advantage that the surgery can be performed only by an orthopedic surgeon or a neurosurgeon because there is no interference from the organs from the skin to the spine.

[0106] Therefore, because the artificial intervertebral disc according to the present disclosure overcomes the problems and disadvantages of conventional anteriorly inserted artificial intervertebral discs and allows patients to maintain mobility while being laterally inserted, it is expected that the artificial intervertebral disc according to the present disclosure can replace not only existing artificial intervertebral discs but also laterally inserted fusion cages.

Claims

1. An artificial intervertebral disc for insertion between two adjacent vertebrae, the artificial intervertebral disc comprising: Superior plate, in contact with the upper vertebrae; the lower plate, which contacts the lower vertebrae; as well as an insert, inserted between the upper plate and the lower plate to allow the upper plate to rotate relative to the lower plate by a set angle, Characterized in that the upper plate and the lower plate have upper and lower wing portions formed along a lateral axis when the insert is inserted.

2. The artificial intervertebral disc according to claim 1, wherein: The thickness of each of the upper plate and the lower plate in the front direction is greater than the thickness in the rear direction.

3. The artificial intervertebral disc according to claim 1 or 2, wherein: An upper ridge portion and a lower ridge portion are respectively formed on an upper plate outer surface of the upper plate and a lower plate outer surface of the lower plate along a lateral axis.

4. The artificial intervertebral disc according to claim 1 or 2, wherein: A plurality of upper protrusions and a plurality of lower protrusions are respectively formed on an upper plate outer surface of the upper plate and a lower plate outer surface of the lower plate.

5. The artificial intervertebral disc according to claim 4, wherein: Each of the plurality of upper protrusions and the plurality of lower protrusions has a quadrangular pyramid shape having a quadrangular cross-section including four line segments respectively perpendicular to the lateral axis and the front-rear axis.

6. The artificial intervertebral disc according to claim 1 or 2, wherein: The insert includes an upper dome portion located on an upper side of the insert and a first axial rotation portion located on a lower side of the insert, An upper groove corresponding to the upper dome portion is formed in the upper plate for sliding contact with the upper dome portion, and A second axial rotation portion contacting the first axial rotation portion is formed on the lower plate.

7. The artificial intervertebral disc according to claim 6, wherein: The upper dome portion is formed in an elliptical hemispherical shape, the major axis of which is on the lateral axis and the minor axis is on the anterior-posterior axis, and by moving the upper dome portion and the upper groove in contact with each other, the upper plate performs lateral bending and anterior-posterior flexion and extension movements relative to the lower plate.

8. The artificial intervertebral disc according to claim 6, wherein: The maximum depth of the upper groove is less than the maximum height of the upper dome portion.

9. The artificial intervertebral disc according to claim 6, wherein: An upper stopper is formed around the upper groove, and the angular momentum of the upper plate is limited by contact of the upper stopper with an insert upper surface of the insert body formed around the upper dome portion.

10. The artificial intervertebral disc according to claim 9, wherein: The insert lower surface of the insert body is flat, and the insert upper surface is formed such that a thickness of the insert upper surface gradually decreases from the upper dome portion to an end of the insert body.

11. The artificial intervertebral disc according to claim 6, wherein: The first axial rotation portion is a lower outer protrusion formed on a lower surface of the insert, the second axial rotation portion is a lower outer groove formed on the lower plate, and the lower outer groove is formed in an arc shape.

12. The artificial intervertebral disc according to claim 11, wherein: A lower center protrusion is formed at the center of a lower surface of the insert, and a lower center groove corresponding to the lower center protrusion is formed on the lower plate.

Images