Multi-lobe artificial spine joint

The present invention relates to artificial joints, and more particularly to an artificial intervertebral disc for replacement of damaged vertebral disks. The present invention relates to an improved artificial intervertebral disc, both for total disk replacement and for replacement of the nucleus.

2. Background Art [0002] Artificial joints are becoming more common in the medical treatment of degenerative bony-joints. Joints can be damaged due to accidents, illnesses, aging, etc. and are often replaced when the pain is strong enough or when the natural movement of the joint is sufficiently weakened. Artificial joints commonly replace the tissue between neighboring bones and can often replace the ends of two adjacent bones that form the joint.

[0003] When replacing a joint, several desirable results are generally achieved. These results include: stability, loading capacity, natural movement behavior, pain relief and reduced risk of injury and reduction of serious injury. Due to the complexity of the human spine, stability is a very difficult parameter to achieve. It is often the case that instability manifests itself as additional wear and premature failure of the artificial joint or lack of support for physiological structures, damage to the adjacent section / joint and the aggravation of pain and disability of the patient.

[0004] Many artificial discs that are currently available tend to lack the durability of the natural spine. Many TDR devices have a "balls in a cavity" or "balls in a tray." One of the problems with these specific designs is that TDR requires adjacent tissues and structures (ligaments and joints) to provide support and stability Due to the physical geometry of these structures, the further the spine is moved from the "neutral position" the more artificial the joint tends to continue to move in this direction, and thus exerts unnatural stress on the surrounding tissues and structures, and requires greater strength to restore the joint to a "neutral position." Over time, constantly applied and increased loads required for the operation of the artificial pond, can lead to muscle damage, related tissues and adjacent spine structures, increasing pain and hindering normal spinal movement. It has also been found that, due to the instability of the replaced discs, scoliosis or curvature can develop in the spine, which often leads to additional degradation of spine-related tissues, such as the failure of adjacent joints.

[0005] US 2003/199981 A1, US 2006/020342 A1 and US 6,039,763 disclose various substitutes for artificial disks.

[0006] The joint neutral position is a normal rest position of the joint and is usually located in the middle of the movement range for the spinal joint. For a typical spine, two adjacent vertebral bodies have movement plates that are approximately parallel to the neutral position.

[0007] Another parameter that must also be controlled is the ability to mimic the natural kinematics of the spinal movement. Many joints in the human body can be adequately represented by simple joints, such as a hinge or a bullet in the socket. Due to the complex structure of the spinal cord, it can not be approximated by simple joints. Many known artificial discs allow the vertebrae to move in a rotational movement having symmetric movements. Differences in movement between the natural joint and the artificial joint may cause undesirable effects on the surrounding muscles and tissues. This can cause degeneration and inability to move and properly control the artificial joint, highlighting the instability of the artificial joint, and can accelerate further joint injuries.

[0008] There is a need for an artificial joint that is more energetically stable with a natural tendency to return the joint to a "neutral position" to reduce stress and fatigue of surrounding tissues and structures. In addition, there is an additional need for an artificial joint that has a more accurate fit to the natural kinematic motion of the spine to reduce pressure and fatigue again on the surrounding tissues and structures. These are just two parameters important for designing a successful spinal disk replacement.

SUMMARY OF THE INVENTION [0009] The object of the present invention is to provide an improved artificial disk. One goal of this invention is to create an artificial disk that better suits the natural movement of the spine. In order to more closely match the natural movement of the spine, one way is to use non-congruent articulation surfaces that allow for asymmetrical and / or connected movement. Such an artificial disc will promote the long-term success of the replaced joint because it maintains more natural movements of the muscles and tissues surrounding the joint. By better matching to natural motion, the artificial disc helps to prevent the degeneration of the surrounding tissues and adjacent episode, while promoting greater mobility of the patient's joint.

[0010] Another object of the present invention is to provide an artificial disk that is more energetically stable. When moved from a neutral position, compressive forces naturally exerted on the spine, e.g. from the force of gravity and tension in the surrounding tissues, drag the artificial joint back to the neutral position rather than from the neutral position. Such an artificial joint is particularly advantageous where there are many discs, because tissue fatigue and joint instability are avoided. These goals were achieved by disclosing the independent claim.

[0011] Accordingly, these and other aspects of the present invention may be embodied in an artificial disc that uses multiple projections to engage the interacting surface to allow naturally limited progressive and rotational movement between two adjacent vertebrae. The cooperating surface usually comprises a plurality of recesses for receiving projections. The protrusions can slide into recesses to provide both forward and rotational movement, i.e. bending / extension, side bending and axial rotation. The protrusions and recesses are preferably configured to provide a coupled translational and rotational movement that causes the joint member to tilt as it slides through the cooperating joint member. One or more of the performances may also be able to lift partially with the recess,

[0012] Alternatively, other structures such as a single projection and recess having a plurality of coupling surfaces as described herein can provide the desired relative motion between the top and bottom of the artificial joint. Similarly, intermediate structures between the top and bottom of an artificial joint can be used to provide the desired motion and stability.

BRIEF DESCRIPTION OF THE DRAWINGS [0013] Various embodiments of the present invention are shown and described with reference to the drawings in which:

FIG. 1 is a side view of an artificial joint of the prior art in accordance with the principles known in the art;

FIG. 2 is a side view of a spine having a plurality of artificial joints of the prior art;

FIG. 3 shows a top view of human vertebrae;

FIG. 4 is a schematic side view of two vertebrae illustrating the vertebral movement in the forward and backward curvature of the spine;

FIG. FIG. 5A is a schematic plan view of a vertebra illustrating the movement of the vertebra towards lateral bending of the spine;

FIG. 5B is a schematic side view of two vertebrae illustrating the movement of the vertebra towards lateral bending of the spine;

FIG. FIG. 6A is a schematic plan view of a vertebra illustrating vertebral movement during rotation of the spine;

FIG. FIG. 6B is a schematic side view of two vertebrae illustrating the vertebral movement of the vertebral column;

FIG. 7A and 7B illustrate the movement of the artificial joint according to the prior art of FIG. 1 in flexion and rotation;

FIG. 8 is an exploded perspective view of a disc of the invention;

FIG. 9 shows a partially cutaway top view of an artificial disc according to the present invention along line 9-9 in FIG. 8;

FIG. 10 is a side view of a portion of the base of the artificial disk of FIG. 9;

FIG. 11 is a top view of a base portion and a cross-sectional view of the protrusions of an artificial disc according to the present invention;

FIG. 12 is a top view of a base portion and a cross-sectional view of the protrusions of a disc of the present invention;

FIG. 13A is a cross-sectional view of the artificial discs of FIG. 8 to 12, along line 13-13 of FIG. 12;

FIG. 13B is a different cross-sectional view of the artificial disk 13a, with protrusions that have been moved in the gutters thereby altering the angle of inclination of the top portion of the artificial disk;

FIG. 13C is a cross-sectional view of an artificial disc according to the present invention;

FIG. 14A is a cross-sectional view of the artificial discs of FIG. 8 to 12, along lines 14-14 in FIG. 12;

FIG. FIG. 14B is another cross-sectional view of the artificial disk of FIG. 14A, with the projection displaced in the tray to thereby change the angle of inclination of the top portion of the artificial disk;

FIG. 15 is a sectional view of the artificial discs of FIG. 8 to 12, along lines 15-15 of FIG. 12;

FIG. 16 is a close-up view of a cross-sectional view of the projection and the tray of an artificial disk according to the present invention;

FIG. 17 is another detailed view of the cross-section of the protrusion and trough of the inventive artificial disk;

FIG. 18 is another top view of the bottom portion and the projections of the top portion of the artificial disc of the present invention;

FIG. 19 (not forming part of the present invention) shows another top view of the artificial disk;

FIG. 20 (not forming part of the present invention) shows a section view of the artificial disk of FIG. 19 along line 20-20;

FIG. 21 is a perspective view of an artificial joint according to the present invention having variously shaped protrusions;

FIG. 22 is a cross-sectional view of the artificial joint of FIG. 21 along lines 22-22 in FIG. 21;

FIG. 23 (not forming part of the present invention) shows a perspective view of another artificial pond;

FIG. 24 (not forming part of the present invention) shows a section view of the artificial joint of FIG. 23 along lines 24-24 of FIG. 23;

FIG. (Not forming part of the present invention) illustrates another artificial joint;

FIG. 26 shows an artificial pond according to the present invention, used as a replacement for the disk core;

FIG. 27 shows an artificial joint having a boundary band according to the present invention;

FIG. 28 (not forming part of the present invention) is a cross-sectional view of another artificial joint;

FIG. 29 (not forming part of the present invention) is another cross-sectional view of the joint of FIG. 28;

FIG. 30 is an exploded perspective view of an artificial pond similar to that of FIGS. 8-18;

FIG. 31 is a view of the pants of the upper portion of the joint of FIG. thirty;

FIG. 32 and 33 are cross-sectional views of the top portion of the joint of FIG. 30 along the section lines 32 and 33 in FIG. 31;

FIG. 34 is a perspective view of the pants of the upper portion of the joint of FIG. thirty;

FIG. 35 is a top view of the bottom portion of the pond of FIG. thirty;

FIG. 36 to 39 show cross-sectional views of the bottom portion of the joint of FIG. 30 along the section lines 36 to 39 in FIG. 35;

FIG. 40 is a perspective view of the bottom portion of the joint of FIG. thirty;

FIG. 41 is an exploded perspective view of an artificial pond similar to that of FIG. 8-18 and 30-40;

FIG. 42 is a perspective view of the pants of the upper portion of the joint of FIG. 41;

FIG. 43 is a view of the trousers of the upper portion of the joint of FIG. 41;

FIG. 44 to 47 are cross-sectional views of the top portion of the joint of FIG. 41 along the section line 44 to 47 of FIG. 43;

FIG. 48 is a perspective view of the bottom portion of the joint of FIG. 41;

FIG. 49 is a top view of the bottom portion of the pond of FIG. 41;

FIG. 50 to 53 show cross-sectional views of the bottom portion of the joint of FIG. 41 along the section line 50 to 53 in FIG. 49;

FIG. 54 is an exploded perspective view of an artificial joint similar to that of FIG. 8-18, 30-40 and 41-53;

FIG. 55 is a perspective view of the pants of the upper portion of the joint of FIG. 54;

FIG. 56 is a view of the pants of the upper portion of the joint of FIG. 54;

FIG. 57 to 60 are cross-sectional views of the top portion of the joint of FIG. 54 along the section line 57 to 60 in FIG. 56;

FIG. 61 is a perspective view of the bottom portion of the joint of FIG. 54;

FIG. 62 is a top view of the bottom portion of the pond of FIG. 54;

FIG. 63 to 66 show cross-sectional views of the bottom portion of the joint of FIG. 54 along the section lines 63 to 66 of FIG. 62;

FIG. 67 is a top view of the bottom portion of the pond of FIG. 54 along with the path lines of the cavity forming tool; and

FIG. 68 is a perspective view of the tool path line, the surfaces formed by the tool and the recesses of FIG. 67.

[0014] It should be understood that the drawings are illustrative and do not limit the scope of the invention, which is defined in the appended claims. Embodiments carry out various aspects and objects of the invention, and each individual figure does not have to realize various aspects or advantages of the invention. It should be noted that it is not possible to clearly show each element and aspect of the invention in one figure, and as such, many figures are shown to separately illustrate various details of the invention more clearly.

DETAILED DESCRIPTION [0015] The invention will now be discussed with reference to the drawings, and the reference numerals thereon so as to enable the skilled person to practice the present invention. The drawings and descriptions are exemplary of various aspects of the invention and are not intended to narrow the scope of the appended claims. In some figures, the spacing between neighboring structures is shown, which remain normally in contact with each other in order to show structures more clearly.

[0016] Many artificial disks are now available or tested. Often they lack the stability of the natural spine. These prior art joints typically comprise a bearing surface that includes a hemispherical shaped socket having a top spherical surface or a sphere or spherical surface 10 placed in a hemispherical cavity 14 as shown in FIG. 1. These joints move through rotation, in a similar way to other known free spherical joints. The rectangle 18 generally indicates the body mass above the joint (as supported by individual joints), such as additional vertebrae, bones and tissues. Circle 22 indicates the element of body weight above the joint, providing a reference point for illustrative purposes. When the ball 10 rotates in position 10 ', which would occur when the joint was bent (where the person having the artificial joint bends), the body mass 18 and the reference point 22 go to the places indicated by 18 'and 22'. It should be noted that the position 22 'is at a lower vertical height than the positions 22.

[0017] It should therefore be noted that when the joint rotates by rotating the ball 10, there is a general lowering of the point 22 when it is moved to position 22 '. The rotation of the joint is favored by the force of gravity when the body mass 18, 22 above the pond is moved to the lower position. The force of gravity itself will apply the force for further movement, moving the body mass, 18, 22 to an even lower position. Additional force is required to move the body mass 18, 22 back to its original position. The spine is in a state of compression due to the force of gravity acting on the body mass above each joint and due to the tension of the muscles and other tissues surrounding each joint. These compressive forces tend to move the joints of the prior art away from the neutral position,

[0018] In this way, it is evident that the shown joint is a joint that is unstable in birth. After moving from a neutral position, squeezing on the joint caused by stresses in the surrounding tissues or body mass above the joint tends to continue to move. The prior art joint is stable at the end points of the movement and not at the central position, i.e. the compressive forces on the joint tend to move the joint to the end points of the movement and not to the center position.

[0019] The muscle structure and other tissue structures surrounding the joint of the prior art must support the joint in a neutral position (i.e. a rest position in which the joint is not displaced, where the surrounding muscles and tissues are in a rest length) relative to the compressive forces acting on the joint. spine, such as the force of gravity. Since the spinal joints are rarely exactly in the neutral position, the surrounding muscles and tissues can undergo a considerable amount of stress when trying to keep such an artificial joint in the desired position, e.g. when the person is sitting or standing upright. In addition, the surrounding muscles and tissues must work harder to restore the joint to a neutral position after bending the spine. This, in turn, can lead to muscle damage, related tissues and adjacent joints / spine structures,

[0020] Therefore, it may be understood how desirable it is to have an artificial disk that is energy stable. It is desirable to have an artificial joint in which the compressive forces acting on the spine, such as the force of gravity acting on the body weight and mass above the joint, have tended to move the joint back to the neutral position and not from the neutral position.

[0021] FIG. 2 depicts an example of the spine of a person who has two or more of the artificial discs of FIG. 1. There are many vertebrae 30a-30g and healthy vertebral disks 34a, 34b, 34e, 34f. Natural vertebral disks between vertebrae 30c and 30d, and between vertebrae 30d and 30e have been replaced by artificial prior art disks 38c and 38d, including spherical disks and a tray, as discussed with reference to FIG. 1. As already mentioned, sphere and chute disks have inherent instability, where compressive forces such as motion stressed by the force of gravity and pull the pond away from the neutral position instead of returning the pond to a neutral position.

[0022] This problem is becoming more and more painful with two or more artificial disks, as shown in 38c and 38d. When one artificial disk, e.g. 38d, is moved from the neutral position, gravitational forces, asymmetric tension in the tissues surrounding the spine, etc. cause the second artificial disc 38c to rotate in the opposite direction to 38d. A patient having a plurality of prior art artificial disks may not be able to maintain the spine in the correct position or position, because artificial disks tend to push the spine into a bent or collapsed position. In this way, scoliosis or skew develops in the spine due to the instability of the artificial disc 38c, 38d and the inability of the body to maintain the spine in the correct position, or much more emphasis is placed on the muscles and connective tissue so that the body maintains the spine in its proper orientation. Over time, bending or collapsing the spine due to artificial disks tends to deteriorate the tissue associated with the spine. It is obvious, therefore, that when the artificial disc is devoid of natural stability, the long-term success of the artificial joint is reduced and is significantly reduced as the number of replaced discs increases. In fact, an artificial joint can accelerate damage to healthy parts of the spine. that when the artificial disc is devoid of natural stability, the long-term success of the artificial joint is reduced and is significantly reduced as the number of replaced discs increases. In fact, an artificial joint can accelerate damage to healthy parts of the spine. that when the artificial disc is devoid of natural stability, the long-term success of the artificial joint is reduced and is significantly reduced as the number of replaced discs increases. In fact, an artificial joint can accelerate damage to healthy parts of the spine.

[0023] A spine having a single prior art artificial disc may cause unwanted and excessive flexing of one or more adjoining natural disks, whereby the spine shape will be similar to that shown in FIG. 2. Unwanted bending of natural disks adhering to an artificial pond may cause or accelerate the degradation of natural joints and may result in the need to replace additional disks.

[0024] Another problem with the artificial disc is the preservation and restoration of natural motion. Providing a natural movement of an artificial pond is important for many reasons, such as ensuring comfortable movement of a person. Perhaps more important is the effect an artificial joint may have on the surrounding tissue. If the movement is unnatural, tissues responsible for the movement of the joint, such as surrounding muscles, tendons, etc., may be adversely affected by the joint. The surrounding tissue may not be able to properly control the joint or it may gradually degenerate as a result of the changed motion of the artificial joint. Thus, providing an artificial joint with natural motion can have a significant impact on the long-term success of an artificial joint.

[0025] Many artificial joints, such as artificial knees or hips, are relatively straight joints with relatively simple movement, such as hinged joints or a ball in the socket. Circles and natural disks, however, have complex movements. Natural disks are soft pads, similar to a mattress. Natural disks allow and support the movement of the spine and allow the spine to move through the disk in combinations of horizontal, vertical and rotational movement to perform normal spinal movements.

[0026] Artificial discs known in the art such as shown in FIG. 1 and 2 do not fit properly with the natural movement of the spine. Many prior art artificial disks allow the spine to move in a rotational motion and have a symmetrical forward and backward motion. As mentioned above, the differences in movement between the natural joint and the artificial joint may cause undesirable effects on the surrounding muscles and tissues. Muscles and tissues are oriented and accustomed to moving the joint in a natural movement and can degenerate or not be able to properly control an artificial joint having an unnatural motion. Degeneration and inability to move properly and control the artificial joint emphasizes the instability of an artificial joint in the state of the art, and may cause or emphasize joint problems discussed with reference to FIG. 1 and 2.

[0027] Thus, it can be seen how desirable it is to have an artificial disk that gives a joint that is energy stable and that provides natural motion. Achieving such results is provided by an artificial disc and a resulting pond that minimizes negative effects on the body, such as degradation of surrounding tissues responsible for joint control and joint damage, to provide support for the body in a natural setting.

[0028] A study of the movement of the cervical spine (neck) reveals that the kinematic movement of the spine is a complex and asymmetric movement. It is observed that the movement of the spine combines translational and rotational movement of the vertebral bodies. Herein, spinal movement is usually described by describing the movement of a portion of the vertebral body above the respective spinal disk relative to the corresponding portion of the vertebral body below the disk. The flexion / dilatation involves the movement of the vertebral body, forwards or backwards, in conjunction with the rotation of the vertebral body, in the same direction of travel. Rotation usually involves rotation of the vertebral body relative to the point slightly behind the center of the vertebral body, combined with some uplift and certain lateral tilt, the vertebral body tilts slightly to the left during rotation to the left, etc. Side bending (sideways) is achieved by the cooperation of multiple joints of the spine in combination of rotation, flexion / extension and lateral tilting. The movement of the natural spine has been described by: Panjabi et al., Spine. December 15, 2001; 26 (24): 2692-700; Ishii et al., Spine. January 15, 2006; 31 (2): 155-60; Ishii and others, Spine. December 15, 2004; 29 (24): 2826-31; Ishii et al, Spine. April 1, 2004; 29 (7): E13944.

[0029] FIG. 3 shows a top view of a vertebra 50. The vertebra comprises different structures for attaching surrounding tissues, spine passage, etc. Since the present invention relates to vertebral disks and delivery of an artificial disk, drawings and discussion of the vertebrae are usually limited to the vertebral body, the rounded face indicated by 50a, which connects to the spinal disc. Thus, the present application shows the vertebral bodies as rounded or cylindrical segments for simplicity. The final (posterior) area of ​​the vertebra disk is indicated at point 54, and the front (front) is indicated at 58. Joints 52 help control the movement of the natural spine as is commonly known. These points are determined when discussing the circle movement.

[0030] FIG. 4 is a side (side) view of two vertebra showing typical movements of the cervical vertebra when bending forward and backward. It is observed that the back 54 and the front 58 of the circle 50 move differently to the circle 46. The front 58 of the circle 50 has a greater amount of vertical movement than the back 54 of the circle 50. It should also be noted that the movement of the circle 50 includes a considerable amount of displacement relative to the circle 46. ​​Disc 62 between the vertebrae is quite matched and changes shape to allow for displacement of the vertebrae, such as forward and backward vertebrae 50. While the present invention discusses an artificial joint in the context of a joint for replacing the cervical disk, it should be understood that it can also be used to replace other vertebral disks,

[0031] FIG. FIG. 5A is a top view of circle 50, illustrating the horizontal movement of the various points of the vertebra when bending laterally. The back 54 of the coil 50 remains substantially in the same place during the lateral flexion. The front 58 and the center 66 of the vertebra 50 rotate relative to the back 54 of the vertebra by moving in a curved motion as indicated by arrows 70 and 74. The left side and right side 78 82 of the circle 50 also move with arcuate motions as by rotating around the back 54 of the circle marked by arrows 86 and 90

[0032] FIG. FIG. 5B is a front view of the circle 50 illustrating the vertical movement of the different points of the vertebra when bending laterally. vertebral 46 and disc 62 are also shown to illustrate the movement of the vertebra 50 with respect to circle 46. In lateral bending, front 58 of circle 50 moves horizontally relative to circle 46, as indicated by arrow 94. Left side 78 and right side 82 circle 50 move vertically as well as horizontally, as indicated by arrows 98 and 102.

[0033] As shown in FIG. 5A and 5B, the lateral bending of the vertebra 50 is a folded motion. the pin 50 slides and turns sideways. the pin 50 slides along the disc 62, rotating around the rearward point 54 of the coil 50. When the left side 78 or the right side 82 of the coil 50 moves sideways, they move vertically, twisting the vertebral body 50 relative to the vertebra 46. As mentioned above lateral flexion usually involves coordinated movements of many spinal joints to achieve the desired movement. FIG. 5A and 5B describe the desired movement of one joint of the spine in order to adapt to the natural lateral curvature of the spine.

[0034] FIG. FIG. 6A is a top view of circle 50, illustrating the horizontal motion of various vertebral points during rotation of vertebra 50. vertebra 50 rotates around point 66 slightly behind the center of the vertebra. Accordingly, the front point 58, the back point 54, and the side points 78, 82 move in accordance with the arrows 56, 60, 80, 84 as shown. FIG. 6B depicts a front view of a circle 50 and a circle 46 and disk 62, illustrating the horizontal movements of the circle 50 during its rotation. The spindle 50 undergoes some vertical lifting as well as a swing in the lateral directions of rotation (i.e., tilting to the left when turning to the left) as indicated by the arrows 96, 100, 104.

[0035] Known prior art artificial disks, such as those shown in FIG. 1, include the configuration of a sphere and socket type, or a hemispherical disk between two sockets, etc. It should be noted that the artificial wand according to the prior art of FIG. 1 does not move in a manner similar to the natural circle as shown in FIG. 3-6. FIG. 7A depicts the movement of the prior art artificial disc that is typical both for bending / stretching and lateral bending. The back 106 and the front end 110 of the upper vertebral body 10 move in accordance with the arrows 114, 118. It should be noted that this movement is quite different from the bending motion and lateral bending of the natural spine as shown in FIG. 4. The side bending motion of the artificial disc is similar to the bending motion, while the natural spine laterally bends in a combination of rotational and bending motion.

[0036] FIG. 7B is a top view of the prior art artificial disk of FIG. 1, illustrating the rotational motion of the resulting joint. The upper surface 10 of the coil rotates around the center 122 as shown by the arrows 126. The ball-and-socket artificial disc rotates around the center of the disc and rotates without any displacement of the vertical disc. As shown in FIG. 5 and 6, the natural vertebrae revolves around the point more towards the back of the disk in conjunction with some lifting and tilting, which is not adequately reproduced by artificial disks of the prior art. The compressive forces in the body (such as the force of gravity and muscle tension, etc.) deflect the natural vertebra in a neutral rotational position, whereas the artificial vertebrae of the prior art are not deflected to a neutral position.

[0037] In this way, it is better understood how the artificially shaped artificial disc forms joints that lack inherent stability (they do not center or are not deflected to a neutral position by natural compressive forces acting on the spine) and which do not reproduce natural movement. spine. Both of these factors cause unnatural movement and exert additional pressure on the muscles, connective tissues and support joints, through which a specific vertebral joint works. Thus, a prior art artificial disc may contribute to further damage to the spine.

[0038] Turning now to FIG. 8, an exploded perspective view of an artificial joint 130 of the present invention is shown. The joint 130 includes a top portion 134 having multiple protrusions 138a, 138b, 138e (generally 138) and a bottom portion 142 having a plurality of recesses 146A, 146B, 146C (generally 146). The protrusions 138 are placed in the recesses 146 when the artificial joint is assembled to replace the disc in the spine. The recesses 146 define a surface where the protrusions 138 contact and define possible ranges of movement of the projections and thus the movement of the top surface 134 relative to the bottom surface 142. The interaction between the surface of the projections and the surface of the recesses provides a controlled movement of the artificial joint 130 that is more reminiscent of motion natural spine.

[0039] In showing the invention in the following figures and discussion of the present invention, recesses and protrusions are often designated by a limited area. It is understood from the following description and figures that the projections and recesses are often smoothly rounded and gradually pass from the surrounding material. Accordingly, there may be no sharp defined edge of the projection or recess. Defined cavity limits, for example, may be an area in which the projection is intended to be moved or an area that is in contact with the projection during the intended use of an artificial joint. In some artificial pond configurations, the protrusion or recess may have a more sharply defined edge, for example when the retaining wall is used to provide a positive boundary to the range of motion of the artificial joint. In other configurations, the recess may be unlimited or has no distinct edge, and may have a different structure, such as a plunger, to limit the movement of the top surface relative to the bottom surface. Thus, it is understood that the term cavity is used broadly to define the general area or portion thereof that receives the projection and is not intended to limit the structure to a structure having opposite side walls or longitudinal nature.

[0040] The following figures and description will provide a better description of the profiles of the protrusions 138 and recesses 146 and of the received range and movement types admitted to the transversal disc 130. It is clear from the figures and discussion that the recesses 146 do not necessarily need steeply inclined vertical edges to completely contain protrusion 138, but may constitute a gradual transition from the surface of the adjacent lower surface 142. The indentation is used to determine the surfaces that are in contact with protrusions 138 and through which protrusions are slid to allow the movement of the artificial disk 130.

[0041] The upper surface 132 of the upper portion 134 and the lower surface 144 (not shown) of the lower portion 142 are configured to attach the bones to form in the artificial joint. Thus, the attachment surfaces 132, 144 may have spines, a porous structure, chemicals to cause binding to bones, etc. as is known in the art. These surfaces are not described in each drawing, but are understood to form part of all artificial joints disclosed herein when necessary. In addition, the base upper portion 134 and / or the bottom portion 142 may be tapered in thickness such that the resulting artificial disk 130 is wedge-shaped, and is not flat. The wedge-shaped artificial disc is useful in solving lordosis, kyphosis, scoliosis or other conditions occurring in the patient's spine. The use of elements of an artificial joint with a conical thickness, yes, to produce a wedge-shaped artificial disc is meant as part of all artificial joints of the invention. It should be noted that such fastening or tapered constructions may be necessary in all cases, or they may often be of different sizes and configurations, especially in situations such as when the artificial joint is dimensioned to replace the nucleus.

[0042] FIG. 9 shows a partial cut-away view of the joint 130 illustrating one possible configuration of the projections 138 and recesses 146. The bottom portion 142 and recess 146, and a cross-sectional view of the projections 138 are visible. The remaining upper part 134 is omitted for clarity. (Although represented in the present application as projections extending downwardly from the top part to the depressions in the bottom part, it should be noted that the configuration may be reversed so that the projections extend upwardly from the bottom part to the seats in the upper part while maintaining stability discussed in this description).

[0043] FIG. 9, and many of the following figures, are taken along line 9-9 in FIG. 8, and are used to indicate the shapes and orientations of protrusions and recesses and the configuration of an artificial joint.

[0044] The protrusions 138 are shaped as hemispherical protrusions over the top portion 134 and are illustrated in the hatch to distinguish them from the cavity 146. The recesses 146 are formed in the bottom part 142. The recesses can be made as hemispherical depressions or can be formed as oval shaped recesses. , kidneys or eggs. For example, the front recess 146a may be formed as an oval recess having a longitudinal axis extending sideways. The side recesses 146b, 146c may be formed as oval depressions with a somewhat longitudinal axis extending parallel to the adjacent edge of the lower layer 142. Regardless of the shape, it is preferred that the recesses are larger than side to side, than the adjacent parts of the associated projections, such that has a somewhat progressive movement,

[0045] As more specifically illustrated in the following figures, the nests are usually rounded to control the movement of the resulting artificial joint. Typically, the bottom part of the seat 146 is relatively flat to allow some forward and inwardly directed nest edges to be more inclined to cause the upper portion 134 to rise when its defined side slides towards the center of the bottom portion 142. The outer portions 146 may simply extend further towards the bottom part of the seats, or they may include a retaining wall or a steeply inclined surface that restricts the movement of the artificial joint 130. It is not intended that the protrusions 138 rise upwardly against the sloping outer portions of the seats 146 to lift the side of the upper portion 134 .

[0046] Furthermore, the recesses 146 can be set at different angles to help control the movement of the joint. The front recess 146a may be oriented so that it is slightly forward and not vertically oriented. The side recesses 146b, 146c may be oriented slightly backwards and sideways.

[0047] FIG. 10 is a side view of the bottom portion 142 of FIG. 9. It can be more clearly seen as the front recess 146a is oriented in the forward direction rather than completely vertical, and the lateral recesses 146b (not shown), 146c are directed so that they are inclined outwards and backwards, completely vertical orientation. The orientation of the recesses 146 assist in controlling the movement of the projections and the top portion; thereby controlling the movement of the artificial disk 130. The movement of the artificial disk 130 will be discussed in more detail in the following figures and description.

[0048] FIG. 11 depicts another partially cut-out top view of the artificial disk 130 illustrating an alternative configuration of the tabs 138 and recesses 146. The projections 138 are shaped to have sides that are generally aligned radially with the posterior point 150 as shown by dotted reference lines extending from the rearward point 150. Similarly, the contours of the seats 146 generally follow these radial lines. This radial orientation supports the disc to rotate around the posterior point 150, imitating the natural spine movement discussed above.

[0049] As the disk rotates, the front projection 138a moves sideways as shown by the arrow 148, and the side protrusions 138b, 138c move as shown by arrows 152 and 156. When the upper part 134 turns to the right, the left side protrusion 138c it rises vertically (from the side) when it touches the sidewall of the cavity, thus imitating the deflection of the natural spine during rotation. When the top surface 134 is turned to the left relative to the bottom surface 142, the right side protrusion 138b is lifted in a similar manner. These movements are also shown in FIG. 13-15.

[0050] FIG. 12 shows another partially cut out view of the artificial disk 130 illustrating an alternative configuration of the protrusions 138 and recesses 146. The lateral projections 138b, 138c, and lateral recesses 146b, 146c are shaped to be slightly curved. The curvature supports the top portion 134 to rotate around the point 154 relative to the bottom portion 142. The curved surfaces of the side protrusions 138b, 138e and lateral recesses 146b, 146c assist in limiting the rotational movement of the disc 130 to a predetermined movement.

[0051] The point 154 is slightly forward of the rear portion (indicated in point 158) of the disk 130, but behind the disk center 162. When the top portion 134 of the disk 130 is rotated, the forward projection 138a moves according to the arrow 166, and the side protrusions move in the direction of the arrows 170 and 174. The shape of the recess 146c causes the left side lip 138c to rise when the top 134 rotates to the right, and the shape of the recess 146B causes the right side protrusion 138b to rise when the top part is rotated to the left - thus imitating the deflection of the natural spine during rotation.

[0052] FIG. 13A shows a section view of the artificial disk 130 of FIG. 8 to 12, along line 13-13 (as shown in FIG. 12). The cross section shows both the top portion 134 and the bottom portion 142 of the artificial disc 130 included in FIG. 8, but the section line is shown in FIG. 12 for clarity, indicating the cross-section shown. It can be seen how the protrusions 138b and 138c have rounded bottom surfaces to allow smooth sliding movement (rotation and translation) across the surface of the recesses 146b 146c. The recesses 146b, 146c are smoothly formed, providing smooth and continuous movement throughout the desired range of motion.

In the rest position, the bottom of the projections 138b, 138c is based on the generally flat bottoms of the recesses 146b, 146c. In this way the pond is very stable, because it does not require any additional work of the pond, to keep it at rest. The compressive forces exerted on the joint, such as the body mass and the tension of the surrounding tissues, tend to deflect the joint to such a state of rest. The resting state of the joint is energetically stable (energetic minimum) and corresponds to the neutral position of the natural spine.

[0053] When the top portion 134 is moved to the right relative to the bottom portion 142 (as is the case in the natural spine), the left lip 138c is raised up as it moves along the surface of the recess 146c. The right shoulder 138b travels substantially horizontally across the generally flat bottom of the recess 146b, which causes the top portion 134 to tilt to match the natural spine and cause the entire disc to expand artificially. Movement to the left of the top surface 134 causes the corresponding protrusion 138b to rise vertically along the side wall of the recess 146b, while the left protrusion 138c slides substantially horizontally, tilting the upper portion 134 to the left, resulting in a total extension of the artificial disc. By matching the pitch and curvature of the projections 138 with recesses 146 of the side walls, upper surface 134 can be made to closely resemble the stroke that occurs in the natural spine. It is therefore evident that compressive forces placed on the spine, such as the weight of the body above the artificial joint, and the tension in the tissues surrounding the natural spine will press the artificial joint back into the neutral position when these forces act to squeeze the artificial joint. Thus, the artificial joint 130 is naturally stable when these compressive forces tend to return the top portion 134 to its original neutral position. Thus, additional fatigue is not exerted on the muscles and connective tissues, which increases the stability of the joint. such as the weight of the body above the artificial joint, and the tension in the tissues surrounding the natural spine will press the artificial joint back into the neutral position when these forces act to squeeze the artificial joint. Thus, the artificial joint 130 is naturally stable when these compressive forces tend to return the top portion 134 to its original neutral position. Thus, additional fatigue is not exerted on the muscles and connective tissues, which increases the stability of the joint. such as the weight of the body above the artificial joint, and the tension in the tissues surrounding the natural spine will press the artificial joint back into the neutral position when these forces act to squeeze the artificial joint. Thus, the artificial joint 130 is naturally stable when these compressive forces tend to return the top portion 134 to its original neutral position. Thus, additional fatigue is not exerted on the muscles and connective tissues, which increases the stability of the joint.

[0054] FIG. 13B depicts the artificial joint of FIG. 13A with the upper part slightly moved to the right. It can be seen how the projection 138c is raised when it moves to the right and how the top portion 134 is tilted to the right. It can be seen how the mean distance between the top portion 134 and the bottom portion 138 increases, resulting in a total extension of the artificial joint. In this way, compressive forces acting on the joint 130 counteract the expansion of the joint and return it to a neutral position.

[0055] The expansion of the artificial joint caused by its movement can be determined in various ways. The volume occupied by the joint, including the volume of the top part 134, the bottom part 138 and the space directly between them, increases in response to the displacement of the joint from the neutral position. Alternatively, the mean distance between the top portion 134 and the bottom portion 142 increases as the joint is moved from the neutral position. While various other terms may be used to describe the expansion of the joint 130, the design of the inventive artificial spinal disc is such that within the intended range of motion of the artificial joint obtained, the artificial joint is expanded as a result of dislocating the joint from the neutral position and thus the compressive forces exerted on the artificial joint will deflect the joint back to the neutral position. This gives the pond, which is inherently stable, when the forces normally placed on the pond during use tend to restore the pond to a neutral position. For the most preferred embodiments of the artificial joint, a joint expansion experience pond for all types of desired movement, as a result of which a joint is compromised by joint compression and thus a joint where the compression naturally exerted on the spine deflects the pond in position neutral in the reaction all types of movement from the neutral position. when the forces normally placed on the pond during use tend to restore the joint to a neutral position. For the most preferred embodiments of the artificial joint, a joint expansion experience pond for all types of desired movement, as a result of which a joint is compromised by joint compression and thus a joint where the compression naturally exerted on the spine deflects the pond in position neutral in the reaction all types of movement from the neutral position. when the forces normally placed on the pond during use tend to restore the joint to a neutral position. For the most preferred embodiments of the artificial joint, a joint expansion experience pond for all types of desired movement, as a result of which a joint is compromised by joint compression and thus a joint where the compression naturally exerted on the spine deflects the pond in position neutral in the reaction all types of movement from the neutral position.

[0056] FIG. 13C depicts an artificial joint similar to that of FIG. 13A and 13B, but where protrusions 138 (shown lateral projections 138b, 138c) are formed on lower part 142 and depressions 146 (shown lateral recesses 146b, 146c) are formed on upper part 134. It should be noted that the direction of inclination of recesses 146 is reversed to achieve the same tilting direction when moving the artificial joint 130. This means that FIG. 13A shows the recesses in which the sections near the outer edges of the bottom part are generally horizontal and the sections adjacent to the interior of the bottom part are inclined, FIG. 13C depicts recesses 146 in which the sections adjacent to the outer edges of the top portion 134 are inclined and the sections adjacent to the interior of the top portion are generally horizontal. The arrangement shown in FIG. 13C ensures that

[0057] It is therefore evident that the artificial joints of the present invention do not always have protuberances 138 on top 134 and depressions 146 on bottom part 142 but may include protrusions on the bottom part and recesses on the top part, or a combination of both protrusions and recesses. on the upper part and the upper part. Generally, when it is desired to have a projection 138 on the lower portion 142 of the joint and a recess 146 on the top 134 of the joint, the relative orientation of the cavity is reversed so that the inclined parts that are placed inside the recess (closest to the center of the joint) are positioned outside the recess and generally flat or less inclined portions that are positioned outside the portions of the recess are placed on the inside of the recess. In most cases, however, it is easier to produce an artificial pond,

[0058] FIG. 14A and 14B are section views of the artificial discs 130 of FIG. 8 to 12, along line 14-14. The cross section represents both the top portion 134 and the bottom portion 142 of the artificial disc 130 included in FIG. 8 to 12, but the section line is shown in FIG. 12 for clarity, indicating the cross-section shown. It can be seen that the side protrusions 138b, 138c (right side notch 138b shown) move upward when the upper part 134 is moved forward (towards the front of the bottom surface 142). The side projection 138b, 138c moves up and forward over the surface of the recess 146b, 146b. In this way, the upper part 134 rotates upwardly around 5-7 degrees, thereby simulating the movement of the natural spine. Front projection 138a, not shown, it may either slide horizontally or even move downward along the inclination in the front recess 146 to provide a dive movement at the front of the joint similar to the natural spine. In contrast to artificial joints of the prior art, however, the joint is configured to return to its original position as soon as the associated muscles are released, using compressive forces acting on the joint to move the projections 138b and 138c back down the side walls associated recesses, and to move or raise the front projection 138a back to the original position.

[0059] FIG. 15 is a sectional view of the artificial disk 130 of FIG. 8 to 12, along lines 15-15, with the addition of a traffic restriction post or limiter that is not shown in the previous figures. The cross-section shows both the upper and lower part of the artificial disk in FIG. 8 to 12, but the section line is shown in FIG. 12 for clarity, indicating the cross-section shown. The front projection 138a and the recess 146a are visible. When the top portion 134 moves back (towards the back of the bottom surface), the front projection 138a is raised vertically so that it moves up the inclined surface of the recess 146A. In order to limit the displacement of the upper part 134 with respect to the lower part 142, one of the upper part and the lower part can have a post 178 formed thereon (not shown in the previous figures),

[0060] Limiting the movement of the post 178 to the space defined by the aperture 182 limits the movement of the top surface 134 relative to the bottom surface 142, thereby restricting the range of motion provided by the artificial disc 130. This may be important in preventing the movement of the disc 130 (top surface 134 moves too far across or from the bottom surface 142) that can occur in the event of an accident or other strong impact.

[0061] The movement of the cervical vertebrae is relatively small. For example, in a forward and backward bend, the vertebrae can tilt backward by about 10 degrees and back by about 5 degrees. The movement itself may typically involve advancing the circle by 1 or 2 mm relative to the circle below. When rotating, the vertebrae can rotate about 4 degrees and move about 0.5 or 1 mm in relation to the circle below. Thus, the hole 182 may be about 4 mm larger than the diameter of the post 178.

[0062] FIG. 13-15 illustrate how the recesses 146 are shaped to both direct the movement of the protrusions 138 in predetermined directions, or to selectively raise one or more protrusions when the upper portion 134 is moved. The protrusions are directed to movements imitating the natural movement of the spine. Because the artificial disc 130 is bent forward, the top portion 134 slides forward and is inclined forward when the side protrusions 138b, 138c are carried vertically through the recesses 146b, 146c.

[0063] As the artificial disk rotates, protrusions 138 and depressions 146 also help to mimic the natural movement of the spine. For example, when the top portion 134 turns to the right, the front lip 138a will move to the right, the left side lip 138c will move left and slightly forward and will be lifted vertically and the right lip 138b will move left and slightly back. By controlling the shape of the protrusions 138 and the shape and curvature of the bottom and side walls of the recesses 146, three-dimensional movements of the upper portion 134 and lower portion 142 can be accurately controlled. Thus, the artificial joint can be formed that significantly mimics the movements of the natural spine than the artificial joint of FIG. . 1.

[0064] FIG. 16 shows a detailed view of the projection 138 and the cavity 146 of the artificial disc 130. Only one projection 138 and recess 146 are shown for clarity, but the principles discussed apply to each combination of the projection 138 / recess 146. The recesses 146 may be formed of substantially planar and horizontal lower. a segment 186, a curved transition section 190, and a more steeply inclined segment 194. The protrusion 138 is shaped with a rounded end 198 that can slide smoothly across the cavity 146 including smoothly passing through the various portions of the cavity. It should be noted that various shapes of projections and depressions, such as curved portions 190,

[0065] The protrusion 138 can be placed in the rest position in the cavity transition section 190 so that the protrusion 138 will move in a substantially horizontal direction as it moves from the sloped portion 194 (left in FIG.16), and so that the projection it will immediately move up as well as horizontally when the projection slides in the directions of the sloping portion of the recess 146 (to the right in FIG. 16). Such an arrangement of projections 138 and recesses 146 can be used to create an artificial disk that is self-centering and energy stable.

[0066] The protrusions 138 and the recesses 146 may be oriented such that the projections slide substantially horizontally when moving substantially from the center of the lower portion 142, and so that the projections slide horizontally and upward when shifting substantially towards the center of the bottom layer 142. Thus, when the artificial disc is advanced forward, which would occur when the spine is bent forward, the front projection 138a moves generally forward and the side projections move both forward and up through the transition portion 190 and the inclined portion 194 of the lateral depressions 138b, 138c . Accordingly, the rear portion of the upper layer 134 of the artificial disk 130 is raised up, resulting in lifting of the body weight and tissues supported above the artificial disk 134. Lifting the upper portion 134, and the mass deposited on it takes place against the force of gravity and against the tension of the muscles and tissues supporting the spine. Thus, the compressive forces of the body mass placed on the joint and the tension in the support tissue cause the joint to return to the neutral position, lowering the raised lateral protrusions 138b, 138c and lowering the upper portion 134 and the assisted weight. A similar method of operation is achieved in the rotation of the artificial disk 130.

[0067] When discussing the forward flexion, it should be understood that each recess 146 can be provided with inclined sidewalls around the entire circumference, thereby selectively controlling the raising of an associated protrusion 138 in response to horizontal movement in any direction. By adjusting the curvature of the projections 138 and the curvature of the recesses 146, substantial motion control of the three-dimensional upper portion 134 is ensured. The artificial disk 130 is therefore advantageous compared to the prior art, because the disk forms a joint that is energetically stable or self-centering and which is pressed against back to the neutral position, while prior art artificial disks create joints that are unstable by gravity and deflected further from the neutral position after being moved from the neutral. In addition, the artificial joints 130 provide movement, which is close to the natural movement of the spine. Adapting more to the natural movement of the spine reduces the negative impact on the tissue surrounding the artificial pond during use and promotes the long-term effectiveness of the artificial joint.

[0069] FIG. 17 shows an alternative configuration of projection 138 and recess 146 of artificial disk 130 to limit the movement range of the resulting joint. The protrusion 138 is shaped with a rounded end 202 that curves more steeply from the point of contact with the recess 146. The recess 146 is formed in the inner retaining wall 206 and the outer retaining wall 210. The protrusion 138 contacts one of the retaining walls after moving to an extreme position inside 146. Any or all of the recesses may be formed in this way with retaining walls to limit the movement of the top surface 134 relative to the bottom surface 142. Thus, the space between the retaining walls 206, 210 and protrusions 138 when the protrusion is in the rest position will determine the range of movement of the upper surface 134,

[0070] The retaining walls 206, 210 may extend completely around the recess 146 and may be joined together or may be made as separate structures. It should be noted that inner retaining walls 206 do not need to be necessary. If each of the recesses 146 is formed from the outer retaining wall 210, the movement range of the protrusions 138 and the top surface 134 will be limited in each direction by the outer retaining walls 210. Similarly, external retaining walls may not be necessary if the joint is fully held by the inner retaining walls.

The inner retaining walls 206 can be used to more accurately control the movement of the projections 138 and the top surface 134 in selected directions. FIG. 18 illustrates such use. For example, internal retaining walls 206b, 206c may be provided on the inner sides of the recesses 146b, 146c. The inner retaining walls 206b, 206c prevent the lateral projections 138b, 138c from displacing in a fully lateral direction. The inner retaining walls 206b, 206c are arranged with side protrusions 138b, 138c so that when rotating, the side protrusions 138b 138c do not move sideways but rotate about the point of contact between the side protrusion and the inner retaining wall.

[0072] For example, if the top portion 134 turns to the right, the side protrusions 138b, 138c can not simply move left or right. The left side projection 138c can move forward and right, and the right side protrusion 138b can move slightly back. The front projection 138a can move to the right and forward. The left side projection 138c is raised vertically as it moves, as discussed previously. Thus, it can be seen that the inner retaining walls 206b, 206c help to limit the motion of the artificial disc to mimic the movement of the natural spine. The inner retaining walls cause the center of rotation to be approximately between the retaining walls, closer to the rear end of the artificial disc, where the center of rotation of the natural spine is located.

[0073] When bending forwards and backwards, the top portion 134 should move in the manner shown by arrows 214, 218, 222, in a manner similar to the natural spine. When rotating, the upper surface should move, as shown by arrows 226, 230, 234, also in a manner similar to the natural spine.

[0074] It should be noted that it may not be possible to ideally reproduce the movement of the natural spine and still achieve the artificial disc 130, which is sufficiently stable. As such, the obtained design can be a compromise between matching natural movement and providing, for example, natural stability and self-centering properties. The artificial pond may be the result of a compromise that provides a good fit to natural movement, natural stability, and which can be made of the desired material without incurring excessive costs or difficulties. The present invention, however, provides a significant improvement over the naturally unstable artificial disks known in the art and more closely mimics the natural movement of the spine.

[0075] FIG. 19 (not forming part of the present invention) shows another partial perspective view of the artificial disk 130 '. The top surface 134 '(FIGURE 20) includes the front projection 138d and the end projection 138e. The bottom surface 142 includes a front cavity 146D and a rear cavity 146E. Although the design of the two projections / recess may not provide an artificial joint that is as stable as a structure with three or more projections, it still represents a marked improvement in stability and movement relative to a conventional artificial disc. For example, the longitudinal configuration of the projections 138d and 138e reduces the effort required to center the joint compared to the hemispherical single projection as in the prior art.

[0076] FIG. 20 (not forming part of the present invention) shows a cross-sectional view of the artificial disk 130 'of FIG. 19 along line 20-20. The protrusions 138 and recesses 146 configured as shown cause the front projection 138d to move forward (to the left) and the rear projection moves forward and upward when the artificial disc 130 'bends forward, tilting the upper portion 134' forward and displacement of the upper surface, in a manner similar to the natural spine.

[0077] Similarly, the end projection 138e slides back and the front projection 138d slides back and up along the recess 146 while bending the rear artificial disc, tilting the top portion 134 'back, and sliding the top portion similar to the natural spine. The upward movement of the top portion 134 'during the forward and backward bending of the artificial disk moves the supported body relative to the force of gravity, causing the gravity force to deflect the artificial disk back to the neutral position as discussed above.

[0078] On rotation, the top portion 134 'rotates approximately around the center of the artificial disc 130' and the upper disk will be slightly raised when the edges of the protrusions 138 contact the sloping portions of the recesses 146 causing gravity to deflect the artificial disc 130 ' in neutral position. By modifying the configuration of the projections and depressions, the top portion 134 'can be rotated about an axis other than the center of the top portion. Thus, an artificial joint can be provided, which more closely resembles the movement of the natural spine.

[0079] It should be noted that the two projections of the artificial disk 130 'of FIG. 19 and 20 may not approximate the natural spine movement as accurately as the three projections of the artificial disk 130 of FIG. 8 to 18, but may be easier to produce. In addition, they are still more durable than the artificial joints of the prior art.

[0080] FIG. 21 is a perspective view of another artificial disk that is similar to that of FIG. 8-18 and works in a similar way. The disc differs in that the front projection 234 when formed at the top 238 of the joint has a more rapidly terminated front side. The bottom 242 is formed with a recess 246 which has a corresponding shape. The lateral projections 250, (254 not shown) and lateral recesses 258, 262 can be formed of similar shapes as the one for the protrusion 234 and the recesses 246, or they can be smoothly shaped in the manner shown above.

[0081] FIG. 22 is a cross-sectional view of the joint of FIG. 21 along line 22-22. It can be seen how the nearly vertical front side of the protrusion 234 and the nearly vertical front side of the recess 246 prevent the upper portion 238 from moving more than a short distance to the right in relation to the lower part 242, which provides a restriction of movement. The use of such a movement restriction helps to ensure that the artificial joint is not over-prolonged after implantation to the patient. As discussed earlier, the recess 246 may be shaped such that the protrusion 234 will move substantially horizontally as it moves to the right of the shown neutral position, and so that the projection moves vertically and left when it moves to the left. relative to the base, and from the shown neutral position. As already mentioned, this creates a stable joint in which compressive forces deflect the joint in a neutral position. It should be noted that one or more projections and depressions can be formed in such a way as to restrict joint movement. One or more different methods of restricting the movement of the artificial joint discussed herein may be used with various joint configurations as set forth herein.

[0082] FIG. 23 (not forming part of the present invention) shows another artificial disc 264 that uses a single projection and a single recess to achieve the stabilization and motion control discussed herein. Top 266 includes a single recess 270 and bottom 274 includes a single projection 278. Recess 270 and protrusion 278 are shaped with rounded and / or curved engaging surfaces in such a way as to ensure smooth movement between them. The protrusion 278 and the recess 270 can be formed as polygonal shapes and other shapes to limit the rotation of the artificial joint and provide more natural movement of the joint. It should be noted that the circular flap 278 and the recess 270 do not limit the top turn 266 relative to the bottom 274 of the joint. The protrusion 278 and the recess 270 can be formed as ovals, squares,

[0083] FIG. 24 (not forming part of the present invention) shows a cross-sectional view of the artificial disk 264. It can be seen how the recess 270 includes an inclined outer wall 282 that extends from the center of the recess and rounded arms 286 and like the protrusion 278 also has a sloping transition area 290 and rounded arms 294. The protrusion arm 294 contacts and slides over the entire inclined outer wall 282 and the arm 286 of the recess 270 contacts and slides over the entire inclined transition area 290 of the protrusion.

[0084] When viewing the artificial joint 264, it can be seen that if the top 266 is moved to the right relative to the bottom 272, the right side of the top will move substantially horizontally along substantially horizontal surfaces and the left side of the mountains will be raised when the arms 286, 294 they will engage about move through sloping transition areas 282, 290. This will take place in the case of lateral bending or bending / widening of the artificial joint 264. Thus, the artificial joint 264 while not ideally close to the natural movement of the spine will create a similar movement and create a joint. which is deflected in the shown neutral position by compressive forces applied to the joint (as is the case when the joint is implanted in the human spine). In order to better control the movement of the artificial pond 164,

[0085] FIG. 25 (not forming part of the present invention) shows a bottom view of an upper portion 298 of an artificial joint, similar to that shown in FIG. 23 and 24. It can be seen how the recess 302 (and the corresponding protrusions formed on the lower part of the joint) can be formed into shapes other than a square or rectangular shape as shown previously. Different shapes of protrusions and depressions will change the movement characteristics of the resulting joint. For example, the protrusion / recess in the shape as shown may tend to rise more when moving in one direction than in the opposite direction or provide different rotational properties during rotation or lateral bending of the joint. In this way, the shape can be chosen which is close enough to the natural movement of the spine and forms the joint,

[0086] FIG. 26 shows the use of the artificial joint 306 of the present invention used to replace the nucleus of the injured spinal disk, leaving the ring 310 (annulus fibrosis ring) of the natural disk in place. Leaving the ring 310 intact as much as possible can be advantageous in some cases as it provides support to the artificial joint 306, which helps to keep the joint 306 centered on the circle 314 or contributes to keeping the top of the joint centered over the bottom of the joint. The artificial pond that is used to replace the nucleus will usually be smaller than the joint used for total disk replacement. Each of the designs of the joints shown above can be used as either a complete disk replacement or a replacement for the kernel,

[0087] FIG. 27 shows an artificial disk 318 with an elastomer band 322 surrounding the joint 318. The band 322 can help in loosely restricting movement of the joint and holding the upper portion of the joint centered above the bottom of the joint. Each of the above joint patterns may include such a band 322 if desired.

[0088] FIG. 28 (not forming part of the present invention) illustrates an alternative artificial disc. The artificial joint 326 includes a base portion 330 having a circular recess 332 formed therein, a toroid 334 and a top 338 that includes a tapered or frustoconical portion that is nested on the toroid 334. Toroid 334 can travel through the base 330 but is displaced towards the center of the base by compressive forces. The top 338 can rotate in the center of the toroid 334 and is raised during its rotation, due to the interaction between the conical portion and the toroid.

[0089] FIG. 29 (not forming part of the present invention) illustrates the joint of FIG. 28, in a position corresponding to a bending / expanding or lateral bending motion. It can be seen how the toroid 334 is raised, that it slides across the recess 332 in the base 330, and how the top 338 is raised as it rotates. The joint 326 uses symmetrical shapes that can be relatively easy to produce and roughly close to the natural movement of the spine. The flexion / extension and lateral bending of the joint are closely related to the natural spine, and are also tilted to a neutral position. While the rotation is free, this movement may be the easiest for the muscles and surrounding tissue to control and is least affected by the compressive forces exerted on the natural spine.

[0090] Referring now to FIG. 30, a perspective view is shown in the exploded state of another artificial pond. The joint, generally numbered 350, is similar to the artificial joints shown in FIG. 8-22. The joint 350 includes an upper portion 354 having a front apex 358 and two side protrusions 362. The joint 350 also includes a bottom portion 366 that includes a front recess 370 and two side recesses 374 that can be connected to one recess as shown. It is clear, however, that the narrow connecting portion, as shown, does not contribute to the movement of the artificial disk and is a convenience to manufacture. The joint works as discussed earlier with reference to FIG. 8 to 18. This means that the top portion 354 slides across the bottom portion 366 to allow forward, side and rotational translational movements. When the top portion 354 slides across the bottom portion 366, the protrusions 358, 362 are typically vertically displaced relative to the bottom portion 366 due to the curved surfaces of the recesses 370, 374. As will be shown in the following figures, the protrusions 358, 362 are generally spherical. and the recesses 370, 374 have round vertical cross-sections. This provides an artificial joint 350 that is closely matched to the natural movement of the spine and provides proper stability as discussed above, but is easier to manufacture.

[0091] Similar to the artificial joints of FIG. 8-22, the protrusions 358, 362 are moved upward relative to the lower part 366 as they move towards the center of the lower portion. This vertical movement causes the entire artificial joint to expand, and thus leads to the joint in which the compressive forces exerted on the joint deflect the joint back towards the neutral position. This vertical movement also causes a joint that provides movement that better suits the natural kinematics of the movement of the human spine. It will be understood that the slopes and changes in the curvature in the recesses 370, 374 can be adapted to control the amount of vertical movement generated by a specific horizontal motion.

[0092] FIG. 31 to 34 show additional details of the upper portion 354 of the joint 350 of FIG. 30. FIG. 31 is a bottom view of top portion 354. FIG. 32 and 33 are sections along the section lines 32 and 33 in FIG. 31. In FIG. 34 is a perspective view of the upper portion 354. An advantage of the joint 350 is that a somewhat simpler and more uniform shape and surface geometry is used than for the joints of FIG. 11, while achieving a movement that closely mimics the natural movement of the spine. The top portion can be formed as a substantially flat disc with hemispherical projections 358, 362. The hemispherical protrusions 358, 362 can be shaped and polished more easily than the more complex protrusions, such as shown in, e.g., FIG. 11.

[0093] FIG. 35 to 40 show additional details of the bottom portion 366 of the joint 350 of FIG. 30. FIG. 35 shows a top view of the lower portion 366 and FIG. 36 to 39 are cross-sectional views of FIG. 35, respectively along the section line 36-39. FIG. 40 is a perspective view of the bottom portion 366. As seen in FIG. 30 and 35, through 40, the two lateral recesses 374 can be connected to each other by the rear bottom portion 366 of the artificial joint. While the lateral projections 362 may never completely go back to the bottom 366 directly between the side recesses 374, it may be easier to fabricate and polish the joint with this configuration.

[0094] It can be seen from FIG. 36 to 39, that the contact surface 378 of the front cavity 370 (by which the forward projection 358 slides when the joint is bent) is slightly curved and inclined. The contact surface 378 of the recess 370 allows the projection 358 to move downward as it moves away from the center of the bottom portion 366 and up when moving towards the center of the bottom portion, e.g. when bending and stretching the joint, and also moves upward. when it moves laterally through the lower part, e.g. during rotation of the joint. The curvature of the contact surface 370 causes a greater vertical movement per unit of horizontal motion when the projection 358 is closer to the center of the lower part 366, compared to the situation where the projection 358 is closer to the outer edge of the lower portion. [0095] In order to facilitate the production of the bottom part 366, the recesses 370, 374 can each have a circular vertical section as seen in FIG. 37 to 39. This allows the circular grinding or polishing tool to be pulled across the bottom part during production to create cavities.

[0096] This can be seen from FIG. 36-39, that the contact surfaces 382 of the lateral depressions 374 have a smaller radius of curvature than the contact surface 378 of the front cavity 370. As such, the contact surfaces 382 of the lateral recess 374 are horizontal or nearly horizontal near the outer edges of the lower portion 366, and more steeply inclined in near the center of the bottom part. As a result, the lateral projections 362 experience little or no vertical movement as they travel over the surface 382, ​​away from the center of the lower portion 366, and move upwardly from the bottom portion 366 of the joint as they move toward the center of the bottom portion. The curvature of the contact surface 382 is such that the vertical movement of the side protrusions 362 is larger per unit horizontal motion when the lateral projections are closer to the center of the bottom portion 366.

The greater the inclination of the greater part of the middle contact surfaces 382, ​​compared to the contact surface 378, provides a total restoring force that presses the artificial joint 350 to a neutral position (i.e., a non-displaced position). Thus, the inclination of the contact surface 378 tends to bias the front protrusion 358 from the center of the bottom part also in the neutral position, but the greater the inclination of the side contact surfaces 382 provide a greater deviation with further forward displacement to the side protrusions 362 and holds the joint in a neutral position when the compression is exerted on an artificial pond 350.

[0098] The shape and curvature of the contact surfaces 378, 382 of the recesses 370, 374 cause kinematic movement of the artificial joint 350, which is similar to the natural movement of the spine and which also tends to return the artificial joint 350 to a neutral position when the joint 350 is placed under compression. The neutral position is when the upper part is positioned above the lower part and not moved from its center. (It should be noted that the upper and lower parts may have a base which is offset slightly from the projections, such that the upper and lower base portions are somewhat aligned although the projections and depressions are in the neutral position. This is within the scope of the invention). In use, the artificial joint 350 will be deflected in the direction of the unstressed neutral position by the compressive forces exerted on the joint by the body, and thus will stabilize the pond. Artificial joint 350 is a good approximation of the natural movement of the spine, i.e. rotation and translation, which occurs when the lateral flexion or rotation of the spine and the displacement that occurs when flexing and extending the spine.

[0099] Referring now to FIG. 41 to 53, another artificial spinal column 386 of the present invention is shown. Artificial joint 386 operates on the principles described above so that the artificial joint provides movement that closely fits the natural movement of the spine and which is inherently stable. The joint 386 is stable so that the joint experiences a full extension due to the intended movement ranges and thus compressive forces exerted on the joint, while in the spine they will tend to return the joint to an undeserved neutral position.

[0100] FIG. 42 to46 show the top portion 390 of the joint 386 in FIG. 41, while FIG. 48 to 53 show the bottom part 394 of the joint. FIG. 42 is a perspective view of upper portion 390. FIG. 43 is a bottom view of the top portion 390 and FIG. 44 to 47 are cross-sectional views of the top portion along the section lines 44 to 47 of FIG. 43. Likewise, FIG. 48 is a perspective view of the lower portion 394 while FIG. 49 is a top view of bottom portion 394 and FIG. 50 to 53 are cross-sectional views of the bottom portion along the section line 50 to 53 of FIG. 49.

[0101] The joint 386 differs from the joints described above in FIG. 8 to 18 and 30 to 40 in that it comprises a single end projection 398 and an end depression 406 and two front side protrusions 402 and two front side recesses 410. Otherwise, top portion 390 and bottom portion 394 fit together in a similar manner and work in a similar way as discussed above. [0102] The joint 386 includes two forward protrusions 402 and a single end projection 398 and corresponding recesses, to better utilize the stabilizing intermittent joint function (52 of FIGURE 3). During the flexion of the joint 386, more pressure is exerted on the two front projections 402 and the front recesses 410, which provides greater lateral stability. When extending the back of the joint 386, more emphasis is placed on the single end projection 398 and the end depression 406, which causes slightly less lateral stability than is ensured by the front bending of the joint. However, the interstitial joints 52, which are located in the back of the spine, provide greater lateral stability in the extension of the joint 386. In this way, the two lateral projections 402 and the recesses 410 are better used in the front portion of the joint 386.

[0103] In another case, the joint 386 of FIG. 41 to 53 is similar to the joint 350 of FIG. 30 to 40. As shown in FIG. 44 to 47, the projections 398,402 have spherical shapes to allow easier grinding and polishing of the top portion 390 when a material such as a polycrystalline diamond (PDC) is used. The recesses have circular vertical sections as shown in FIG. 50 to 53, so as to allow easier grinding and polishing with a circular rotary tool using PDC or similar material. The rotary tool can be dragged by means of a relatively simple horizontal motion to grind the shown shapes of the recesses. The joint 386 has been cut into a trapezoidal shape, because this shape is similar to the available space in the spine with complete replacement of the disk. It should be noted

[0104] Referring now to FIG. 54 to 66, another artificial spinal cord according to the present invention is shown. FIG. 54 is a perspective view of joint 414. FIG. 55 to 60 show the upper portion 418 of the joint 414 while FIG. 61 to 66 show the lower part 422 of the joint 414. FIG. 55 is a perspective view of upper portion 418. FIG. 56 is a bottom view of upper portion 418 and FIG. 57 to 60 are cross-sectional views of the top portion along the section lines 57 to 60 in FIG. 56. Similarly, FIG. 61 is a perspective view of the bottom 422, while FIG. 62 is a top view of bottom portion 422 and FIG. 63 to 66 are cross-sectional views of the bottom portion along the section line 63 to 66 of FIG. 62.

[0105] The joint 414 is similar to the joint 386 discussed above in that it includes a single end projection 426 and an end depression 434 and two front side protrusions 430 and two front side recesses 438. The joint 414 differs in that the protrusions 426, 430 and the recesses 434, 438 are larger than those of the joint 386, so as to further reduce the pressure of the joint and further reduce the stress exerted on the material used to construct the joint.

[0106] The protrusions 426, 430 have a spherical shape and the recesses 434, 438 have round vertical cross sections to allow for simplified grinding and polishing as discussed above and to provide the desired movement as described herein to closely reproduce the natural backbone movement. In order to increase the stability of the joint 414, the protrusions 426, 430 and the recesses 434, 438 were moved close to the edges of the upper part 418 and the lower part 422, while maintaining a suitable range of movement. This increases the "trace" of the contact points and maximizes the forces that tend to restore the joint to a neutral position when the joint is squeezed.

[0107] By way of example, it has been found that the dimensions below provide a suitable artificial joint for total disk replacement for the cervical spine discs. Top portion 418 and bottom portion 422 are about 15.5 mm wide and about 11.9 mm long (front to back). The relatively flat base 442 of the upper portion 418 (extending between the protrusions 426, 430) is approximately 1.9 mm thick. In the upper part 418, the end projection

426 is approximately 11.2 mm in diameter and has a center that is positioned along the transverse axis, and located approximately 1.7 mm from the rear edge of the top portion. The end lip 426 is arranged such that it extends approximately 3.6 mm from the base portion 442, in a total combined thickness of approximately 5.5 mm.

[0108] The two front side projections 430 have a diameter of approximately 6.9 mm and have means that are positioned at a distance of approximately 7.2 mm, in the front portion of the center of the end projection 426 and laterally approximately 5.35 mm from the transverse centerline of the top portion. 418. The front lateral projections 430 extend approximately 2.9 mm from the base portion 442, to a total combined thickness of approximately 4.8 mm. Section lines 57 to 60 in FIG. 56 pass through the projection means 426, 430.

[0109] FIG. 67 and 68 show the grinding / polishing paths of the tool used to produce, as shown in bottom part 422. FIG. 67 is a top view of the tool paths superimposed on the bottom portion 422 of the joint, and FIG. 68 is a perspective view of the tool paths along the resulting notches and recesses of the tool. The end depression is made by moving a circular 15 mm diameter grinding / polishing tool with a horizontal arc 450 (such that the grinding diameter is perpendicular to the arc), in which the arc has approximately 1.8 mm radius and where the arc center 454 is transversely centered in the lower part 422, placed 6.4 mm behind the central reference point 446 (which is transversely centered and approximately 5.4 mm from the front edge or 6.6 mm from the rear edge), i.e.

[0110] The two lateral recesses 438 are made by moving a grinding / polishing wheel tool with a diameter of 10.8 mm across the tool path identified by the path segments 462a, 466a, 470a, 474a, 474b, 470b, 466b and 462b. The tool path sections 462a, 462b are straight lines about 3.5 mm long. The tool path sections 466a, 466b are arcs having means 478a, 478b and radii about 0.9 mm. The tool path sections 470a, 470b are straight lines about 1.7 mm in length. The tool path sections 474a, 474b are arcs having a common center 482 and radii of about 6 mm. The center points 478a, 478b are located approximately 7 mm on each side of the lateral centerline and are approximately 4 mm in front of the reference point 446, placing points approximately 10.6 mm in front of the center point 454 and approximately 1,

[0111] The individual sections of the tool path 462 through 474 are connected in a continuous path as shown and are in one plane. The plane in which the tool path segments are located is angled relative to the lower section so as to incline the forward portion 438a of the forward recesses 438 as shown in FIG. 64. As mentioned above, this causes the front end of the upper portion 418 to slightly decrease relative to the front end of the lower portion 422 when the spine bends, reproducing the natural motion of the spine. For the embodiment shown in FIG. 54 to 68, the plane is inclined downwards by 17 degrees towards the front side of the pond. As such, the most forward tool path point 486 (track segments 462 through 474) is located at a distance of about 0,

[0112] It should be noted that the inclination of the plane in which the tool path sections 462 through 474 are arranged may be zero if a simplified manufacturing process is desired. When the plane of the tool path section 462 through taper 474 is inclined, it can usually be adjusted to correspond to a particular disk that is replaced, and can often be inclined at an angle in the range of about 7 to about 27 degrees below the horizontal plane. As discussed above, the middle cervical artificial disk will have a slope of about 17 degrees. The inclination of the plane will usually be varied by adjusting the height of the foremost tool path point 486 so as to maintain the front recesses 438 at a similar average height and maintain the height of the top portion 418 relative to the bottom portion 422 at a similar distance,

[0113] Artificial spine joints here are advantageous in that they provide a movement that closely mimics the artificial motion of the spine. An important aspect is to provide a tied movement, where the displacement or rotation of the upper part relative to the lower part necessarily produces a tilting of the upper part relative to the lower part. While some of the artificial spine joints of the prior art make it possible to move and allow the joint to be rotated in a manner similar to the ball and socket, there is no coupling of translation and rotational movement that is close to the natural movement of the spine. This results in a pond that provides an unnatural movement after implantation into the spine and which adversely affects the spine as described herein. On the contrary, the artificial joints of the spine according to the invention provide movement,

[0114] It should be noted that the artificial disks disclosed herein cause a high contact pressure between the protrusions and the recesses, because the curved surfaces of the projections contact the recesses on a very small contact surface. Thus, the material used to form such a projection must withstand very high pressures without deformation or without using, breaking, or otherwise degrading the material. Thus, a preferred embodiment of the present invention provides artificial discs that are made of diamond, such as polycrystalline diamond (PDC) moldings. PDC is a hard enough material that is resistant to wear and deformation.

[0115] US Publication No. 2003/0191533 to Diamicron, Inc., discusses the production of artificial joints using diamond. The publication discloses to those skilled in the art how to produce artificial joints of artificial diamonds. With respect to the present invention, it is evident that it is more difficult to form the surface of a diamond-shaped disc, which is a complex surface with multiple protrusions or multiple recesses. It is much easier to create a simple regular surface, for example a sphere-shaped or hemisphere-shaped socket.

[0116] A presently preferred method of making a disc of the invention utilizes electrohydrodynamic treatment (EDM) to form articular surfaces. The artificial diamond compound can be pressed in approximately the desired shape. The EDM tub device can then be provided with an electrode that is in a reverse shape to the part being manufactured. EDM and the custom electrode are then used to burn the diamond compound and refine the shape of the artificial pond element. The produced element can then be polished to the finished surface. It is therefore obvious that the difficulty of creating an artificial diamond disk is a difficult process and may require some simplification of the artificial disk design.

[0117] Another presently advantageous method of manufacturing an artificial joint in accordance with the present invention uses a circularly shaped grinding and polishing tool to be used across the recess and creating curved contact surfaces therein, and a bowl-shaped grinding and polishing tool to form spherical projections on the surfaces lower. This is particularly advantageous when creating more geometrically shaped contact surfaces of the artificial joints of FIG. 31 to 66.

[0118] While PDCs or other diamond materials are preferred, other biocompatible metals and ceramics may also be used. Specialists knowing the construction of artificial joints will be familiar with many such materials and the relative advantages and disadvantages of each of them.

[0119] Thus, an improved artificial spinal disc has been disclosed.

Dimicron, Inc. , US Plenipotentiary:

EP 2 114 313 B1 Z-15086/16