TW201328655A - Intervertebral implant - Google Patents

Abstract

An intervertebral implant is provided comprising a single piece hollow body with an upper wall (1) configured to engage a first vertebral end plate and a lower wall (2) configured to engage a second vertebral end plate, with two opposite sidewalls (3, 4) connecting the upper wall and the lower wall, respectively, and with a load transmitting part configured to transmit load between the upper wass and the lower wall; wherein the body is configured to assume a compressed condition in which a distance between the upper wall (1) and the lower wall (2) defines a first height (h1) of the implant and an expanded condition in which the distance between the upper wall (1) and the lower wall (2) defines a second height (h2) of the implant that is greater than the first height (h1); and wherein the implant is made of a material that exhibits shape memory properties.

Description

Intervertebral implant

The invention relates to an intervertebral implant, comprising a single-piece hollow body, which is configured to be combined with the upper wall of the first vertebral endplate, and is configured to join the lower wall of the second vertebral endplate, connecting the upper wall and the lower wall. Two opposing side walls, and a load transfer assembly, constitute a load transfer between the upper and lower walls. The implant can be in a compressed state having a first height and a first width, and an expanded state having a second height that is greater than the first height. The implant is made of a material that exhibits shape memory properties such that the implant can be in an expanded state when heated.

US 2003/0105631 A1 describes a spacer made of a shape memory material for easy insertion into the intervertebral space. Known spacers suitable for artificial disc replacement surgery, including shape memory material members, which can be flattened or pressed prior to insertion, can be in the desired biconvex shape after positioning.

Other types of intervertebral disc filling techniques using shape memory properties are also known. For example, US 2009/0076613 A1 describes a disc replacement procedure comprising a substrate, a top plate, and at least two springs disposed between the substrate and the top plate, wherein the springs each have a ring segment and are connected to the two ends of the substrate and the top plate, respectively. The spring can be made of a shape memory alloy.

It is an object of the present invention to provide an intervertebral implant that can be used, for example, for intervertebral disc replacement, that is simple in design, has fewer components, and is convenient to handle.

This object is solved by the intervertebral implant of claim 1 of the patent application. Further developments are listed in the scope of the patent application.

An intervertebral implant is a one-piece implant that is small in size in the compressed state and allows for expansion in at least one spatial direction. In the expanded state, the configuration transfers the load from one vertebra to the other. The shape of the implant in the expanded state can be pre-deformed, and the expanded state is automatically achieved when the implant is inserted and reaches body temperature.

The small design of the implant in a compressed state facilitates the insertion of the intervertebral implant. have When the wall is smooth, it can be introduced into the intervertebral space first, which is more convenient for insertion. In the compressed state, the intervertebral endplate can be protected from bonding to the joint on the implant for safe and convenient handling. In the expanded state, the intervertebral implant can be secured by engagement with the vertebral endplate.

Other features and advantages of the present invention will be apparent from the description of the embodiments illustrated in the appended claims.

1‧‧‧Upper wall

1a, 1b‧‧‧ upper wall

2‧‧‧ Lower wall

2a, 2b‧‧‧ lower wall

3,4‧‧‧ side wall

5‧‧‧Combination

5a‧‧‧ sharp free edge

6‧‧‧Long

6a‧‧‧The recess of the lower wall

7‧‧‧ slitting

8‧‧‧ pillar

8a‧‧‧ first end

8b‧‧‧second end

8c‧‧‧ slit

9‧‧‧ Lateral convex

10,10',10"‧‧‧ intervertebral implants

20‧‧‧掣子 or ratchet lock

50‧‧‧Compression device

51‧‧‧Clamps

52‧‧‧Support surface

53‧‧‧ pressure plate

54‧‧‧ platen convex

60,60',60"‧‧‧ insertion device

61‧‧‧ sleeve

61a‧‧‧ first end of the sleeve

61b‧‧‧Sleeve second end

62‧‧‧ handle

63,63'‧‧‧ gripper

63a, 63b, 63a', 63b'‧‧‧ Arms

64‧‧‧Latch

65‧‧‧Hands

67‧‧‧ gripper

67a‧‧‧The front of the grip

68‧‧‧Latch

69‧‧‧Cylindrical recess

80,81‧‧ ‧ pillar

80a, 81a‧‧ ‧ the first end of the pillar

80b, 81b‧‧‧ pillar second end

l‧‧‧Implant length

h ₁ ‧‧‧first height

h ₂ ‧‧‧second height

w ₁ ‧‧‧Width of upper and lower walls

w ₂ ‧‧‧Width of the expanded state of the implant

A‧‧‧ longitudinal axis

1 is a perspective view showing a compressed state of the intervertebral implant of the first specific example; FIG. 2 is a side view of the intervertebral implant shown in FIG. 1; and FIG. 3 is an intervertebral implant shown in FIG. A top view of the implant; FIG. 4 is another side view of the intervertebral implant shown in FIG. 1; FIG. 5 is a perspective view of the first embodiment of the intervertebral implant in an intermediate state; 5 is a side view of the intervertebral implant; FIG. 7 is a plan view of the intervertebral implant shown in FIG. 5; and FIG. 8 is another side view of the intervertebral implant shown in FIG. 5; Figure 9 is a perspective view showing the first embodiment of the intervertebral implant in an expanded state; Figure 10 is a side view of the intervertebral implant shown in Figure 9; and Figure 11 is an intervertebral implant shown in Figure 9. a top view of the implant; Fig. 12 is another side view of the intervertebral implant shown in Fig. 9; and Fig. 13 is an intervertebral implant compression device with an intervertebral implant inserted therein in an expanded state Fig. 14 is a side view of the device shown in Fig. 13 together with the implant; Fig. 15 is another side view of the device shown in Fig. 13 together with the implant; Fig. 16 is an intervertebral implant Compression device along with insertion and compression a perspective view of the intervertebral implant; Figure 17 is a side view of the device shown in Figure 16 along with the implant; Figure 18 is another side view of the device shown in Figure 16 along with the implant; Figure 19 A perspective view of a first embodiment of the intervertebral implant insertion device; a 20th view is a partial enlarged view of the device shown in Fig. 19; and a 21st view is a device shown in Fig. 19 in the second state. Partially enlarged view; Figures 22 to 27 are schematic diagrams of the steps of insertion of intervertebral implants between the two vertebrae; Fig. 28a is a front view of the intervertebral implant inserted into the intervertebral space in an expanded state; and Figs. 28b and 28c are diagrams of Fig. 28a Detailed view of the detail; Figure 29 is a side view of the intervertebral implant inserted into the intervertebral space in an expanded state; and Figs. 30 to 32 are perspective views of the intervertebral implant in an expanded state together with the insertion device of the second specific example, respectively. , side view and top view; Figures 33 to 35 are respectively a perspective view, a side view and a top view of the intervertebral implant in a compressed state together with the second embodiment of the insertion device; Figures 36 to 38 are respectively a second specific example The intervertebral implant is in an expanded state together with a perspective view, a side view and a top view of the third embodiment insertion device; FIGS. 39 to 41 are respectively a second embodiment of the intervertebral implant in a compressed state together with the attached third specific example A perspective view, a side view, and a top view of the insertion device; and Fig. 42 is a side view of the intervertebral implant of the third embodiment.

As shown in Figures 1 to 4, the intervertebral implant 10 of the first embodiment is a one-piece hollow body comprising an upper wall 1, a lower wall 2, and a side wall 3 connecting the upper wall 1 and the lower wall 2 , 4. The length l of the upper wall 1 and the lower wall 2 allows the intervertebral implant to be completely accommodated in the intervertebral space between the two vertebrae. The width w _{1 of the} upper wall 1 and the lower wall 2 is smaller than the length l. The thickness and dimensions of the walls cause the implant to substantially form a closed loop made of flat strips, as shown in Figure 2. In particular, the dimensions include the ability of the implant to be in a compressed state as shown in Figures 1 through 4, wherein the distance between the upper and lower walls is minimal and defines the first height h _{1 of the} implant, and The expanded state shown in Figures 9 to 12, wherein the distance between the upper wall 1 and the lower wall 2 is the largest and defines the second height h _{2 of the} implant. The side walls 3, 4 are outwardly curved so that they are rounded to facilitate insertion of the implant into the intervertebral space.

A plurality of joint portions 5 are provided on the upper wall 1 and the lower wall 2. The joint portion 5 has a rib shape and has a substantially sharp free edge 5a which is bent outward into the side wall direction. The ribs extend across the full width of the intervertebral implant. In the specific example shown, the ribs are arranged in groups and are offset from the center of the intervertebral implant in the longitudinal direction. Between the side walls 3, 4 and the ribs 5, a ridge portion 6 is provided on the upper wall 1 and the lower wall 2, extending across the walls in the width direction. The height of the ridge 6 relative to the joint 5 in the compressed state (see Figure 2 for details) causes the ridge 6 to prevent the joint 5 from engaging with the vertebral endplate during insertion.

The intervertebral implant further includes two opposing slits 7, extending through the side walls 3, 4 and above Wall 1 and lower wall 2 are at a distance from the center of the implant in the length direction. The length of the slit 7 is larger than the distance between the slits in a plan view, see Fig. 3. Thus, the top view of the intervertebral implant (as shown in Figure 3) is substantially H-shaped. The slits are bifurcated into the respective halves by the slits 7, and the first and second upper wall portions 1a, 1b, and the first and second lower wall portions 2a, 2b are formed as shown in Figs.

The implant is provided with a post 8 at the center in the longitudinal direction, having a first end 8a and a second end 8b. The first end 8a forms a single piece with the upper wall 1. The second end 8b is free. The thickness of the strut 8 in the width direction makes it deformable. As shown in Figures 1 and 2, the post 8 is deformable to encounter the lower wall 2 at a location between the first end 8a and the second end 8b when the implant is in the compressed state shown in Figure 8, and The distance between the upper wall 1 and the lower wall 2 in the height direction is defined as the first height h _{1 of} the implant. Referring to Figures 9 and 10, in the expanded state, the struts extend substantially vertically or at an angle relative to the height direction. When the implant is in the expanded state, the free end 8b of the strut is supported by the lower wall 2. The strut 8 may be provided with a detent or ratchet locking portion 20 on the inner side of the lower wall 2, as shown, for example, in Figure 28c. These dice 20 can be, for example, a front shallow concavity that terminates the free end 8b of the strut 8. Further, the slit 8c extends from the free end 8b in the direction of the first end 8a through the struts so that the struts are also split, as shown in Figures 9 and 12.

The intervertebral implant is in a state of two ends and an intermediate state therebetween; that is, a compressed state, the distance between the upper wall 1 and the lower wall 2 in the height direction is the smallest, see Figures 1 to 4; and the expanded state, the upper wall 1 and The distance between the lower walls 2 is the largest, as shown in Figures 9-12. Figures 5 to 8 show the intermediate state, the distance between the upper wall 1 and the lower wall 2, which has not yet reached the full distance in the height direction.

Referring to Figures 5 to 12, in the intermediate and expanded state, the distance between the upper wall 1 and the lower wall 2 is increased, so that the height of the implant is also increased. The slit 7 also expands into a V shape, and the width increases toward the side wall. The upper wall portions 1a, 1b and the lower wall portions 2a, 2b are respectively increased in distance from each other in the direction away from the implant. Thus, as seen in Figure 12, the intervertebral implant is slightly X-shaped in plan view. Therefore, the width of the implant is in the middle and in the expanded state, which is increased compared to the compressed state. Therefore, the intervertebral implant is configured to expand in three dimensions in three dimensions.

The side view in the expanded state is shown in Fig. 10, and the portion adjacent to the side wall includes a substantially V-shaped cross section. In the central portion of the implant, the upper wall 1 and the lower wall 2 are at a maximum distance from each other. The ridge portion 6 no longer protrudes above the joint portion 5. Therefore, the joint portion 5 protrudes from the upper and lower walls and can be combined with the end plate of the vertebra.

The intervertebral implant system is made of a shape memory material. This similar shape memory material can For example, shape memory alloys, such as certain nickel titanium alloys that exhibit shape memory properties, especially Nitinol. The material can also be a shape memory polymer material.

The shape memory effect of the shape memory material is the result of the phase transition inside the material at the transition temperature. The intervertebral implant can be fabricated in a pre-deformed expanded state at about a predetermined temperature below body temperature or below body temperature, as shown in Figures 9-12. The implant is then cooled and compressed to a compressed state. Compression can be performed using, for example, the apparatus shown in Figures 13-18. The implant compression device 50 includes a holder 51 that houses the implant 10 and includes a support surface 52 to support, for example, the implant upper wall 1. A pressure plate 53 is provided to form a counter wall that is pressed against the implant, which in the illustrated example is the lower wall 2. The pressure plate includes a projection 54 that extends toward either side of the support surface at either end of the pressure plate. The convex portion 54 serves as a lateral step member for preventing the implant from further expanding in the width direction when compressed in the height direction. An actuator is also provided to move the pressure plate 53 downward.

The compression of the implant can be in a cooled state to cool the implant below the transition temperature. The implant remains compressed unless heated above the transition temperature.

A first specific example of the intervertebral implant 10 insertion tool will be described with reference to Figs. The tool 60 includes a sleeve 61 having a first end 61a and an opposite second end 61b. The handle 62 can be provided on the sleeve 61, for example near the second end 61b. An actuator (not shown) of the gripper 63 is provided in the sleeve. The gripper 63 extends beyond the sleeve at the first end 61a. The gripper has a fork shape and has two arm portions 63a, 63b which can be in an open state. As shown in Fig. 20, the arm portions 63a, 63b are apart from each other by a distance greater than the width of the implant, and a convergent state, as shown in Fig. 21. The arms 63a, 63b are at a small distance from each other, and the pins 64 at the ends of the arms 63a, 63b are directed toward the inside of the fork to engage the implant. A handle 65 can be provided to connect to the actuator. The handle is rotated in one direction, that is, the grip claw is pulled into the sleeve 61, and as shown in Fig. 20, the arm portions 63a, 63b are converged as shown in Fig. 21. The length of the arm substantially corresponds to the length of the implant in the compressed state, so that as shown in Fig. 23, when the implant 10 is joined by the pin 64 of one side wall 3, the other side wall 4 bears against the end of the arm.

The use of the intervertebral implant 10 is illustrated in Figures 22-29. As shown in Fig. 22, the intervertebral implant is in a compressed state prior to being grasped by the insertion device 60. As shown in Fig. 23, the implant is sandwiched between the arms 63a, 63b of the gripper 63 such that the latch 64 engages one side of the implant and the opposite side bears against the bottom of the fork grip. Therefore, the intervertebral implant is firmly held by the gripper.

The intervertebral implant is then introduced into the intervertebral space using a lateral approach, see Figures 24-26. As shown in Fig. 24, the rounded edges of the arms 63a, 63b and the rounded sides 3, 4 are available. Smooth insertion into the implant. As can be seen from Fig. 25, the height of the ridge portion 6 in the compressed state of the implant is the same as or slightly higher than the peak 5a of the joint portion 5, so that the rounded shape of the ridge portion protects the vertebral end plate at the time of insertion. The damage of the joint portion 5. At the final insertion state shown in Fig. 26, the implant 10 held by the grip arm portion has been completely introduced. The arms 63a, 63b of the gripper 63 are then opened and the insertion device is carefully removed. See Figure 27 for details, the implant is still in compression. Using the action of body heat, the implant begins to expand as shown in Figure 28a, thus expanding the intervertebral space. In the expanded state, the joint 5 is combined with the vertebral endplate to prevent movement of the intervertebral implant. The struts 8 eventually extend substantially vertically and are held by the scorpion 20, see Figures 28b and 28c. In the expanded state, the strut additionally carries a load acting on the upper wall and is transmitted to the lower wall. At the time of expansion, the intervertebral implant also expands in the width direction, as shown in Fig. 29, thus allowing the load to be transferred to a greater width, making the implant more stable.

Referring to Figures 30 to 35, a second specific example of the insertion device is shown. The insertion device 60' includes a grip 67 having a front portion 67a whereby the latch 68 extends in a vertical direction of the longitudinal axis A of the grip 67 to a distance from the front portion 67a. The length of the latch 68 is less than the width of the slit 7, see Fig. 32, so that the latch 68 can be moved into and out of the implant while the implant is in an expanded state. The distance between the outer surface of the latch 68 and the rounded front portion 67a of the gripper 67 substantially corresponds to the thickness of the side walls 3, 4, so that when the latch is combined with the implant, as shown in Fig. 34, the gripper can be held firmly There are implants.

In use, the insertion device 60' is coupled to the implant in an expanded state. The implant is then compressed with an attached insertion device. In the compressed state, the gripper and the implant are connected to each other. The implant is then inserted into the intervertebral space. After the implant has been expanded, the grip is removed because the length of the latch 68 is less than the width of the slit 7.

A third embodiment of the intervertebral implant and a third embodiment of the insertion device will be described with reference to Figs. 36 to 41.

The intervertebral implant 10' of the second embodiment has a rib-like projection 9 on one side wall 3 extending laterally away from the side wall 3. Due to the slit 7, the upper wall portions 1a, 1b and the respective lower wall portions 2a, 2b are associated with the lateral projections 9. The outer end of the convex portion has a substantially circular cross section.

The insertion device 60 of the third embodiment is similar to the insertion device 60 of the first specific example, comprising a sleeve 61 and a grip 63' extending from the first end 61a of the sleeve. The grip 63' includes arms 63a', 63b' At a distance from its free end, there is a cylindrical recess 69 that matches the shape of the lateral projection 9 of the implant. The grip 63' is in an open position and the arms are at a distance from one another to allow the side of the implant Introduced to the convex portion 9. The gripper 63' can be again in a converging position, as shown in Figs. 39 to 41, the lateral convex portion 9 It is clamped by the arm and firmly held in the recess 69. When the implant is in the compressed state, the grip width is such that all of the lateral projections 9 are substantially in the width direction and can be accommodated between the grip arm portions as shown in Fig. 39. The use of the implant and the insertion device is similar to the use of the implant and device in the first embodiment. The implant is inserted into the device in a compressed state. When the implant is between the two vertebrae, the opposite side wall 4 without the lateral projections 9 is the first portion of the introduction. Thanks to the sleek side wall, it can be easily introduced.

Fig. 42 shows a third specific example of the intervertebral implant. The implant 10" differs from the implant of the previous specific example in that it includes two legs 80, 81. The legs each have a first end 80a, 81a, between the convex portion 5 and the ridge portion 6, integral with the upper wall The second ends 80b, 81b of the struts 80, 81 are free and placed in the recess 6a of the lower wall 2, corresponding to the ridges 6 of the implant in the expanded state. In the compressed state, the struts are deformed toward the side walls 3, 4. The struts 80, 81 also have slits (not shown). Other parts of the implant are identical to the first or second embodiment.

Modifications are conceivable in the above specific examples. More than two pillars of equipment. The struts can have other shapes to allow for transmission loads. The pillars may be integrally formed with the upper or lower wall. Two slits 7 or more can be provided to give the implant a more complicated structure. For example, more slits can be provided to increase expansion. There is no need to open the seam. In this case, the implant can only be expanded in one direction, such as the height direction.

The width of the upper and lower walls does not need to be full length. For example, one end can be wider than the other end.

3,4‧‧‧ side wall

5‧‧‧Combination

6‧‧‧Long

7‧‧‧ slitting

8‧‧‧ pillar

8c‧‧‧ slit

l‧‧‧Implant length

w ₂ ‧‧‧Width of the expanded state of the implant

Claims (16)

An intervertebral implant comprising: a one-piece hollow body having a top wall (1) constituting a first vertebral endplate, and a lower wall (2) constituting a second vertebral endplate, respectively connected to the upper wall and The opposite side walls (3, 4) of the lower wall and the load transmission assembly (8; 80, 81) constitute a transmission load between the upper wall and the lower wall; wherein the body is in a compressed state, the upper wall (1) and the lower portion The distance between the walls (2) is defined as the first height (h ₁ ) of the implant, and the expanded state, the distance between the upper wall (1) and the lower wall (2) is defined as the second height of the implant (h ₂ ) , greater than the first height (h ₁ ); and in which the implant exhibits shape memory properties. The intervertebral implant of claim 1, wherein the load transfer assembly (8; 80, 81) comprises at least one post (8; 80, 81) connected to the upper wall (1) or the lower wall (2) The first end (8a, 80a, 81a) and the second end (8b, 80b, 81b), and wherein the struts are deformable, deformed in a compressed state, and are not deformed in an expanded state. An intervertebral implant according to claim 2, wherein in the deformed state, at least one of the struts (8; 80, 81) extends substantially parallel to the upper or lower wall. An intervertebral implant according to claim 2 or 3 wherein, in the undeformed state, at least one of the struts (8; 80, 81) extends substantially perpendicular to the upper or lower wall. An intervertebral implant according to any one of claims 2 to 4, wherein the second ends (8b, 80b, 81b) of the struts (8; 80, 81) are free when deformed. An intervertebral implant according to any one of claims 2 to 5, wherein the second end (8b, 80b, 81b) of the strut (8; 80, 81) terminates in the dice when it is in an expanded state (20, 6a) Insiders. An intervertebral implant according to any one of claims 2 to 6, wherein the struts (8; 80, 81) extend across substantially the entire width of the upper wall (1) or the lower wall (2). An intervertebral implant according to any one of claims 1 to 7, wherein the implant (10, 10', 10") is pre-formed in an expanded state, and wherein the implant (10, 10', The shape of the 10") in the compressed state is achieved by deformation of the preformed implant at a temperature below the material transition temperature. An intervertebral implant according to any one of claims 1 to 8, wherein the upper wall (1), the lower wall (2) and the side walls (3, 4) form a closed loop. An intervertebral implant according to any one of claims 1 to 9, wherein the width of the upper or lower wall in the compressed state is defined as the first width w ₁ of the implant, and wherein the upper or lower wall is in an expanded state. The width is defined as the second width w ₂ of the implant, and the second width w ₂ is greater than the first width w ₁ . An intervertebral implant according to any one of claims 1 to 10, wherein at least one slit (7) is provided, extending completely through the side wall (3, 4), into the upper wall (1) and the lower wall (2) And wherein the slit (7) width is substantially the same in the compressed state, and is increased toward the sidewall in the expanded state. An intervertebral implant according to claim 11 wherein there are two slits (7) extending from the side walls (3, 4) toward the center of the upper wall (1) and the lower wall (2), and wherein The slit length is greater than the maximum width of the slit. An intervertebral implant according to any one of claims 1 to 12, wherein at least one of the side walls (3, 4) is rounded outward. An intervertebral implant according to any one of claims 1 to 13, wherein the upper wall (1) and the lower wall (2) comprise a convex portion (5), such as a tooth, which constitutes a combined vertebral endplate, and wherein the upper wall ( 1) and the lower wall (2) includes a ridge (6) which is rounded outward and disposed between the side walls (3, 4) and the convex portion (5), the bulge protruding farther than the convex portion, and being in a compressed state The same height. An intervertebral implant according to any one of claims 1 to 13 further includes a projection (9) extending laterally from at least one of the side walls (3, 4) for engagement with the insertion device. An intervertebral implant according to any one of claims 1 to 15, wherein the implant (10, 10', 10") has a substantially H-shaped profile in a compressed state in a plan view or a bottom view, and is expanded The state is a substantially X-shaped profile.