Spinal cage system

Abstract

This simplifies the installation process when placing a spinal cage between two vertebral bodies. [Solution] The inserter 1 comprises an outer member 20 having an outer tip portion 202d and an inner member 10 having an engaging portion 13 that can engage with the engaged portion 103 of the spinal cage 100. The outer tip portion 202d has an angle restricting surface 202h and an angle restricting recess 202g. The angle restricting surface 202h restricts the rotation angle to a first angle θ1 when it comes into contact with the first surface portion 102a of the spinal cage 100, and restricts the rotation angle to a second angle θ2 when it comes into contact with the second surface portion 102b. The angle restricting recess 202g restricts the rotation angle to a third angle θ3 between the first angle θ1 and the second angle θ2 when the portion of the spinal cage 100 located at the boundary between the first surface portion 102a and the second surface portion 102b is located within the angle restricting recess 202g.

Description

Technical Field

[0001] The present invention relates to a spinal cage system.

Background Art

[0002] Conventionally, a spinal cage system including a spinal cage and an inserter for inserting the spinal cage into the space between two vertebral bodies of the spine has been known (see, for example, Patent Document 1).

[0003] The inserter has a drive shaft, a guide sleeve, and an adjustment nut. The drive shaft can move forward or backward with respect to the sleeve by rotating the adjustment nut. The drive shaft has an engaging portion that can engage with the end of the spinal cage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using the spinal cage system S shown in Patent Document 1, it is necessary to finally install the spinal cage at a predetermined position (for example, the central position) of the vertebral body at a predetermined angle (for example, an angle parallel to the left - right direction (lateral direction) of the vertebral body) while rotating the spinal cage around an axis extending in its thickness direction by the inserter, and the operation requires skill.

[0006] The present invention has been made to solve the above problems, and an object thereof is to facilitate the installation operation when installing a spinal cage between two vertebral bodies.

Means for Solving the Problems

[0007] A spinal cage according to one aspect of the present invention comprises a spinal cage having first and second ends spaced apart in a predetermined direction, a first surface portion and a second surface portion adjacent to each other and intersecting at a predetermined angle at the first end, and an engaging portion located at the first end, and an inserter that engages with the spinal cage, wherein the inserter comprises a hollow outer member having an outer tip portion, and an inner member having an engaging portion that can engage with the engaging portion of the spinal cage, penetrating the outer member and movable inside the outer member, wherein the inner member is movable between a spaced-out position that positions the spinal cage spaced apart from the outer tip portion when the engaging portion is engaged with the engaging portion of the spinal cage, and a contact position that positions the spinal cage in contact with the outer tip portion, and the outer tip portion is the inner The member has an angle restricting surface and an angle restricting recess that restrict the rotation angle of the spine cage from a predetermined reference position to the engaged portion when the member is in the contact position, the angle restricting surface restricts the rotation angle to a first angle when the first surface of the spine cage comes into contact with the angle restricting surface when the inner member is moved from the separated position to the contact position while engaged with the spine cage, and restricts the rotation angle to a second angle when the second surface comes into contact with the angle restricting surface, the angle restricting recess is a recess that opens to the angle restricting surface, and restricts the rotation angle to a third angle between the first angle and the second angle when the corner where the first surface and the second surface of the spine cage intersect is located within the angle restricting recess when the inner member is moved from the separated position to the contact position while engaged with the spine cage. [Effects of the Invention]

[0008] According to the present invention, the installation process when placing a spinal cage between two vertebral bodies can be made easier. [Brief explanation of the drawing]

[0009] [Figure 1]Figure 1 is an overall view showing the spinal cage system S in this embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view illustrating the insertion procedure of a spinal cage using a spinal cage system. [Figure 3A] Figure 3A is a perspective view showing the vertebral cage. [Figure 3B] Figure 3B is a view taken in the direction of arrow IIIB in Figure 3A. [Figure 4] Figure 4 is a cross-sectional view taken along line IV-IV in Figure 1. [Figure 5] Figure 5 is a magnified perspective view showing the groove of the inner member. [Figure 6A] Figure 6A is a perspective view showing the inner member in the first rotational position to achieve this engagement state. [Figure 6B] Figure 6B is a perspective view showing the inner member in the second rotational position to achieve this disengaged state. [Figure 7] Figure 7 is an explanatory diagram illustrating the disengaged state of the inner member. [Figure 8] Figure 8 is an explanatory diagram illustrating the state in which the inner member is engaged and the spinal cage is separated from the outer tip in a first position (separated position). [Figure 9] Figure 9 is an explanatory diagram illustrating the state in which the rotation angle of the spine cage is restricted to a first angle (first state). [Figure 10] Figure 10 is an explanatory diagram illustrating the state in which the rotation angle of the spine cage is restricted to a second angle (second state). [Figure 11] Figure 11 is an explanatory diagram illustrating the state in which the rotation angle of the spine cage is restricted to a third angle (third state). [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. Figure 1 is an overall view showing the spinal cage system S in this embodiment.

[0011] The spinal cage system S includes a spinal cage 100 and an inserter 1. The spinal cage 100 is an artificial implant that is replaced in a damaged intervertebral disc of a patient in spinal surgery or the like.

[0012] The inserter 1 is used to insert the spinal cage 100 between two vertebral bodies V and install it at a predetermined position (for example, the central position in the width direction of the vertebral body V).

[0013] FIG. 2 is a cross-sectional view schematically showing the insertion operation of the spinal cage 100 using the spinal cage system S. In FIG. 2, the leftmost figure shows the start state of insertion, and the rightmost figure shows the completion state of insertion. As shown in this figure, the operator holds the spinal cage 100 at the tip of the inserter 1 and inserts the spinal cage 100 between two vertebral bodies V (only one vertebral body V is shown in FIG. 2, and the illustration of the other vertebral body V located on the near side of the paper surface is omitted). Then, while further inserting the inserter 1 deeper, the spinal cage 100 is gradually rotated with the tip of the inserter 1 (the engaging hole 103 described later) as a fulcrum. And when the spinal cage 100 becomes substantially parallel to the left-right direction of the vertebral body V, the inserter 1 is separated from the spinal cage 100. Thus, the installation of the spinal cage 100 is completed.

[0014] [Details of the spinal cage 100] Next, the details of the spinal cage 100 will be described with reference to FIGS. 3A and 3B. FIG. 3A is a perspective view showing the spinal cage 100. FIG. 3B is a view taken in the direction of arrow IIIB in FIG. 3A. In the following description, as shown in FIGS. 3A and 3B, the thickness direction, longitudinal direction, and width direction of the spinal cage 100 are defined, but these direction definitions are shown for convenience in explaining the structure of the spinal cage 100 and do not limit the configuration of the spinal cage 100 of the present disclosure in any way.

[0015] The spinal cage 100 has a plate shape that is long in a predetermined direction as a whole. The spinal cage 100 has a first end portion 110 and a second end portion 120 spaced apart in the longitudinal direction (the predetermined direction) when viewed from the thickness direction. The first end portion 110 has an engaging hole 103 penetrating in the thickness direction. The engaging hole 103 is, for example, a cylindrical hole. The engaging hole 103 can be engaged with an engaging plate portion 13a of the inserter 1 (see FIG. 4 and the like described later). Note that the reference numeral 104 in the figure is a through hole for inserting a graft bone. The through hole 104 is located between the first end portion 110 and the second end portion 120.

[0016] The spinal cage 100 has a pair of surfaces 101 facing each other in the thickness direction and side surfaces 102 connecting the pair of surfaces 101.

[0017] The pair of surfaces 101 are surfaces facing two adjacent vertebral bodies V adjacent to both sides in the thickness direction of the spinal cage 100. Each of the pair of surfaces 101 has a plurality of convex portions 101a arranged in the longitudinal direction. In other words, each of the pair of surfaces 101 has a jagged shape including a plurality of convex portions 101a. Each convex portion 101a has a triangular shape when viewed from the width direction of the spinal cage 100.

[0018] The side surface 102 connects the peripheries of the pair of surfaces 101. The side surface 102 extends over the entire circumference of the spinal cage 100. The side surface 102 has a first surface portion 102a, a second surface portion 102b, and a third surface portion 102c at the first end portion 110.

[0019] The first surface portion 102a and the second surface portion 102b are adjacent to each other and intersect at a predetermined angle α (see FIG. 3B) when viewed from the thickness direction. The first surface portion 102a and the second surface portion 102b are continuously connected via the third surface portion 102c. The predetermined angle α is preferably 90° or more and 120° or less, and is 80° as an example in this example.

[0020] The third surface portion 102c is located between the first surface portion 102a and the second surface portion 102b. The third surface portion 102c connects the first surface portion 102a and the second surface portion 102b. The third surface portion 102c has a substantially arc shape that bulges outward from the spinal cage 100 when viewed from the thickness direction.

[0021] The spinal cage 100 further has a guide recess 105 that opens across the first surface 102a and the second surface 102b. The guide recess 105 opens across the first surface 102a, the second surface 102b, and the third surface 102c located between them. The guide recess 105 has a flattened shape. When viewed from the thickness direction, the guide recess 105 includes an engagement hole 103 on the inside of its outer edge (see Figure 3B). The guide recess 105 is capable of receiving the guide projection 202i of the outer tip portion 202d, which will be described later.

[0022] [Details of Inserter 1] Next, we will describe the details of inserter 1 with reference to Figure 4. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 1.

[0023] The inserter 1 includes an inner member 10, an outer member 20, a male screw member 30, an operating member 40, a handle member 50, and a holding member 60.

[0024] The inner member 10 penetrates the outer member 20 in its axial direction. The inner member 10 is movable relative to the outer member 20 in the axial direction. Specifically, the inner member 10 has a first shaft portion 11, a second shaft portion 12, and an inner tip portion 13 including an engagement plate portion 13a. The first shaft portion 11, the second shaft portion 12, and the inner tip portion 13 are located in this order from the base end side to the tip end side of the inner member 10.

[0025] The first shaft portion 11 has a cylindrical shape. The base end of the first shaft portion 11 constitutes the inner base end, which is the end opposite to the inner tip portion 13. A male screw member 30 is fixed to the inner base end.

[0026] The first shaft portion 11 has a groove 14 on its outer circumferential surface. The groove 14 is engageable with the protruding pin 203, which will be described later. The groove 14 functions as a cam groove that defines the movement path of the inner member 10. The groove 14 is located on the tip side of the first shaft portion 11. Figure 5 is an enlarged perspective view of the groove 14 of the inner member 10. As shown in this figure, the groove 14 has a continuously connected first groove portion 14a, a second groove portion 14b, and a third groove portion 14c. The first groove portion 14a, the second groove portion 14b, and the third groove portion 14c are located in this order from the base end side to the tip end side of the inner member 10. The first groove portion 14a and the third groove portion 14c extend linearly along the axial direction of the inner member 10. The first groove portion 14a and the third groove portion 14c are located at different circumferential positions around the axis of the inner member 10. The second groove 14b is inclined circumferentially from the base end to the tip end of the inner member 10.

[0027] When the protruding pin 203 is engaged with the first groove 14a or the third groove 14c, the inner member 10 is restricted from rotating around its axis by the protruding pin 203 and can only move in the axial direction. On the other hand, when the protruding pin 203 is engaged with the second groove 14b, the inner member 10 can rotate around its axis while moving relative to the outer member 20 in the axial direction. The second groove 14b is an example of a shape that allows the inner member 10 to move in the axial direction in conjunction with the rotational movement of the inner member 10 between the first rotation position and the second rotation position. The second groove 14b does not necessarily have to be inclined in a straight line; for example, it may be curved in an arc shape.

[0028] The second shaft portion 12 has a rectangular plate shape (see Figures 6A and 6B described later). The second shaft portion 12 is connected to the tip of the first shaft portion 11. The second shaft portion 12 has a plate width approximately equal to the diameter of the first shaft portion 11.

[0029] The inner tip portion 13 has an engaging plate portion 13a connected to the tip portion of the second shaft portion 12. The engaging plate portion 13a has a fan-shaped design.

[0030] The outer member 20 has a first outer cylinder 201 and a second outer cylinder 202. The first outer cylinder 201 and the second outer cylinder 202 are coaxially positioned. The first outer cylinder 201 and the second outer cylinder 202 are positioned in this order from the base end to the tip end in the axial direction of the outer member 20.

[0031] The first outer cylinder 201 has a first cylindrical portion 201a, a second cylindrical portion 201b, and a third cylindrical portion 201c. The first cylindrical portion 201a, the second cylindrical portion 201b, and the third cylindrical portion 201c are located in this order from the base end to the tip end of the first outer cylinder 201.

[0032] The first cylindrical portion 201a has a frustoconical portion 201d that decreases in diameter towards the base end, and a cylindrical portion 201e connected to the base end of the frustoconical portion 201d. As shown in Figure 1, the frustoconical portion 201d has a pair of recesses 201h that open radially in opposite directions. The wall surface of the recess 201h along the axis of the frustoconical portion 201d has an opening 210. The opening 210 has a rectangular shape. The opening 210 extends along the axial direction of the frustoconical portion 201d. Returning to Figure 4, the cylindrical portion 201e has a recess 201f on its outer circumferential surface. The recess 201f extends along the entire circumferential direction. The cylindrical portion 201e constitutes the outer base end. An operating member 40, described later, is connected to the outer base end.

[0033] The second cylindrical portion 201b has a cylindrical shape extending in the axial direction. The second cylindrical portion 201b has a smaller outer diameter than the first cylindrical portion 201a and the third cylindrical portion 201c. The third cylindrical portion 201c has a substantially cylindrical shape. The outer circumferential surface of the third cylindrical portion 201c has a male threaded portion 201g.

[0034] The second outer cylinder 202 is connected to the tip of the first outer cylinder 201. Specifically, the second outer cylinder 202 has a fourth cylindrical portion 202a, a fifth cylindrical portion 202b, and a pin holding portion 202c.

[0035] The fourth cylindrical portion 202a is located closer to the base end than the fifth cylindrical portion 202b. The fourth cylindrical portion 202a and the fifth cylindrical portion 202b are connected via the pin holding portion 202c.

[0036] The fourth cylindrical portion 202a has a cylindrical shape. The fourth cylindrical portion 202a is fitted inside the third cylindrical portion 201c of the first outer cylinder 201.

[0037] The pin holding portion 202c has a cylindrical shape. The pin holding portion 202c extends in a direction perpendicular to the axial direction of the fourth cylindrical portion 202a. A protruding pin 203 is mounted inside the pin holding portion 202c. The protruding pin 203 protrudes inward from the fifth cylindrical portion 202b. The protruding pin 203 engages with the groove 14 of the inner member 10.

[0038] The fifth cylindrical portion 202b has a cylindrical shape. The base end of the fifth cylindrical portion 202b is connected to the pin holding portion 202c. The tip of the fifth cylindrical portion 202b constitutes the outer tip portion 202d, which is the tip of the outer member 20. Details of the outer tip portion 202d will be described later.

[0039] The handle member 50 is positioned to surround the outside of the second cylindrical portion 201b of the outer member 20. The handle member 50 can be grasped by the operator's hand. The handle member 50 has an outer circumferential surface having a plurality of recesses 50a. The plurality of recesses 50a have a function as an anti-slip surface. The handle member 50 is held between the first cylindrical portion 201a of the first outer cylinder 201 and the holding member 60. The holding member 60 is screwed onto the male threaded portion 201g at the tip of the first outer cylinder 201.

[0040] The male threaded member 30 has a substantially cylindrical shape. The male threaded member 30 has an outer circumferential surface 30a surrounding its axis. The outer circumferential surface 30a has a male threaded portion. The male threaded member 30 is attached to the base end of the first shaft portion 11 of the inner member 10. The male threaded member 30 is coaxial with the first shaft portion 11. The male threaded member 30 is connected to the first shaft portion 11 via a connecting pin 31. The connecting pin 31 connects the male threaded member 30 and the first shaft portion 11 by passing through them radially. In this way, the male threaded member 30 is rotatable together with the first shaft portion 11.

[0041] The operating member 40 has a substantially cylindrical shape overall. The operating member 40 is rotatably fitted onto the cylindrical portion 201e that constitutes the outer base end. The operating member 40 is also screwed onto the outer circumferential surface 30a of the male screw member 30. Specifically, the operating member 40 has a first inner circumferential surface 40a that is fitted onto the cylindrical portion 201e and a second inner circumferential surface 40b that is screwed onto the outer circumferential surface 30a of the male screw member 30. The second inner circumferential surface 40b has a female screw portion.

[0042] The operating member 40 is immovably connected to the cylindrical portion 201e via a pair of connecting pins 41. The pair of connecting pins 41 are positioned parallel to each other across the axis of the cylindrical portion 201e. The pair of connecting pins 41 are rotatable around the axis of the cylindrical portion 201e while engaging with the recess 201f of the cylindrical portion 201e.

[0043] As described above, the operating member 40 is screw-connected to the male screw member 30, so when the operating member 40 is rotated in direction A1 in Figure 4, the male screw member 30 moves in direction B1. On the other hand, when the operating member 40 is rotated in direction A2 in Figure 4, the male screw member moves in direction B2. Furthermore, since the male screw member 30 is connected to the inner member 10, the inner member 10 can move back and forth in the axial direction in conjunction with the rotation of the operating member 40. When the inner member 10 moves back and forth, if the protruding pin 203 is engaged with the second groove 14b of the groove 14 (see Figure 5), the inner member 10 moves in the axial direction while rotating around the axis.

[0044] The inner member 10 can switch between an engaged state, where it engages with the spinal cage 100, and a disengaged state, where the engagement is released, by rotating around its axis.

[0045] Figure 6A is a perspective view showing the inner member 10 in the first rotational position to achieve this engaged state, and Figure 6B is a perspective view showing the inner member 10 in the second rotational position to achieve this disengaged state. The spinal cage 100 is omitted in Figures 6A and 6B for clarity.

[0046] In the engagement state shown in Figure 6A (i.e., the state in the first rotation position), the engagement plate portion 13a of the inner tip portion 13 engages with the engagement hole 103 of the spinal cage 100.

[0047] In the disengaged state shown in Figure 6B (i.e., the second rotation position), the inner member 10 rotates 90° around its axis from the first rotation position. As a result, the engaging plate portion 13a rotates 90° around its axis from the engaged state, and the engagement between the engaging plate portion 13a and the engaged hole 103 is released.

[0048] The inner member 10 is further movable between a first position (corresponding to the separated position; see Figure 8 below) in which the spinal cage 100 is positioned away from the outer tip 202d when engaged, and a second position (corresponding to the contact position; see Figures 9 to 11 below) in which the spinal cage 100 is positioned in contact with the outer tip 202d. The inner member 10 can be switched between this first and second position by moving along the axial direction.

[0049] [Outer tip section 202d] The outer tip portion 202d will be described in detail with reference to Figures 6A and 6B. In Figures 6A and 6B, the first direction D1, the second direction D2, and the third direction D3 are defined for convenience to facilitate the explanation of the outer tip portion 202d, but these direction definitions do not limit the configuration of the spinal cage system S of this disclosure. Direction D1 is the direction along the width direction of the spinal cage 100 when the inserter 1 is in use, direction D2 is the direction along the thickness direction of the spinal cage 100 when the inserter 1 is in use, and direction D3 is the direction along the axial direction of the inserter 1. Directions D1, D2, and the third direction are orthogonal to each other.

[0050] The outer tip portion 202d includes a rectangular cylindrical portion 202A which comprises a pair of first side walls 202e facing in the D1 direction and a pair of second side walls 202f facing in the D2 direction, an angle-regulating surface 202h which is the tip surface of the rectangular cylindrical portion 202A, a guide projection 202i which protrudes from the angle-regulating surface 202h toward the tip side (one example being the outside), and an angle-regulating recess 202g.

[0051] The guide projection 202i is connected to one of the pair of first side walls 202e. The guide projection 202i is engageable with the guide recess 105 of the spinal cage 100 (see Figure 3A). The dimension of the guide projection 202i in the D2 direction is the same as or slightly smaller than the thickness of the guide recess 105. In this example, the guide projection 202i does not engage with the guide recess 105 when the inner member 10 is disengaged (see Figure 7 below). On the other hand, the guide projection 202i is engageable with the guide recess 105 when the inner member 10 is engaged (see Figures 8 to 11 below).

[0052] The angle regulating surface 202h is positioned perpendicular to the axis of the inner member 10. The angle regulating surface 202h has a flat surface shape.

[0053] The angle-restricting recess 202g has a U-shape that opens towards the tip side of the outer member 20 when viewed from the D2 direction. The angle-restricting recess 202g penetrates both of the pair of second side walls 202f in the D2 direction. The angle-restricting recess 202g has a bottom portion 202k located at the end opposite to the opening side in the recess direction when viewed from the D2 direction.

[0054] As will be described later, the angle restricting surface 202h and angle restricting recess 202g can restrict the rotation angle of the spine cage 100 around the engagement hole 103 (more specifically, the axis of the engagement hole 103) when the inner member 10 is in the second position (the position in which the spine cage 100 is in contact with the outer tip portion 202d).

[0055] [Explanation of how to use Inserter 1] Next, the usage modes of the inserter 1 will be explained with reference to Figures 7 to 11. The left side of each figure shows a schematic plan view of the outer tip portion 202d in each usage mode, and the right side shows the operating state of the operating member 40.

[0056] Figure 7 shows the inner member 10 in the disengaged state described above. In the disengaged state, as described above, the inner member 10 is positioned at the second rotation position (position in Figure 6B), so that the entire engaging plate portion 13a of the inner member 10 fits within the guide recess 105 of the spinal cage 100. Therefore, the engaging plate portion 13a does not engage with the engaging hole 103 of the spinal cage 100. The disengaged state is necessary, for example, in the preparation stage before engaging the inner member 10 with the spinal cage 100 at the start of spinal surgery, or when detaching the inner member 10 from the spinal cage 100 at the end of spinal surgery. To achieve the disengaged state, the position of the inner member 10 in the axial direction is adjusted by rotating the operating member 40. In this example, in the disengaged state, mark M coincides with the first scale line L1 on the side of the opening 210. In the disengaged state, the protruding pin 203 (see Figure 4) engages with the first groove portion 14a (see Figure 5) of the groove 14.

[0057] Figure 8 shows the state in which the inner member 10 is in the engagement state described above and the spinal cage 100 is in a first position separated from the outer tip 202d. In this state, the inner member 10 of the spinal cage 100 is in the first rotation position (position in Figure 6A), so that the engagement plate portion 13a of the inner member 10 engages with the engagement hole 103 of the spinal cage 100. On the other hand, since the spinal cage 100 is separated from both the angle-restricting recess 202g and the angle-restricting recess 202g of the outer tip 202d, the rotation angle of the spinal cage 100 is not restricted. That is, the spinal cage 100 can rotate freely around the engagement hole 103. This state is necessary, for example, when changing the rotation angle of the spinal cage 100 in conjunction with the insertion movement during spinal surgery. To achieve this state, the surgeon rotates the operating member 40 in the A1 direction from the state in Figure 7. As a result, the inner member 10 moves in the B1 direction. As a result, the protruding pin 203 (see Figure 4) engages with the second groove portion 14b (see Figure 5) of the groove 14. Since the second groove portion 14b is inclined in the circumferential direction with respect to the axial direction, the inner member 10 moves in the direction of B1 and rotates around its axis to reach the first rotation position (position in Figure 6A). When the inner member 10 reaches the first rotation position, the engaging plate portion 13a engages with the engaging hole 103 of the spinal cage 100. At this time, the mark M on the inner member 10 coincides with the second scale line L2 on the side of the opening 210.

[0058] Figures 9 to 11 show a state in which the inner member 10 is engaged and the spinal cage 100 is in a second position in contact with the outer tip portion 202d. In this state, the rotation angle of the spinal cage 100 is restricted by contact with the angle-restricting recess 202g or angle-restricting recess 202g of the outer tip portion 202d. The difference between Figures 9 to 11 is the rotation angle of the spinal cage 100 restricted by the outer tip portion 202d (more specifically, the angle-restricting surface 202h or angle-restricting recess 202g), with the state in Figure 9 corresponding to the first state of this disclosure, the state in Figure 10 corresponding to the second state of this disclosure, and the state in Figure 11 corresponding to the third state of this disclosure.

[0059] Figure 9 shows the spinal cage 100 fixed in a predetermined reference position. This state restricts the rotation angle of the spinal cage 100 from the predetermined reference position to 0° (an example of the first angle θ1). This state is necessary, for example, when inserting the spinal cage 100 into the spinal surgery described above (see Figure 2). The predetermined reference position is, for example, a position where the longitudinal direction of the spinal cage 100 coincides with the axial direction of the inner member 10, but is not limited to this.

[0060] To achieve this state, the operator rotates the operating member 40 in the A1 direction from the state shown in Figure 8. As a result, the inner member 10 moves in the B1 direction, and the protruding pin 203 (see Figure 4) engages with the third groove portion 14c (see Figure 5) of the groove 14. The inner member 10 then moves linearly in the B1 direction (without rotation around the axis) along the axial direction, which is the extension direction of the groove 14. As a result of this movement in the B1 direction, if the second surface portion 102b of the spinal cage 100 comes into contact with the angle regulating surface 202h of the outer tip portion 202d, the spinal cage 100 is fixed in the predetermined reference position by this contact. In other words, the spinal cage 100 is fixed at a rotation angle of 0° (an example of the first angle θ1) from the predetermined reference position. At this time, the mark M on the inner member 10 coincides with the third scale line L3 on the side of the opening 210.

[0061] Figure 10 shows the spinal cage 100 in a state where its rotation angle is restricted to 80° (an example of the second angle θ2) around the engagement hole 103 from a predetermined reference position. This state is necessary, for example, when fixing the final rotation angle of the spinal cage 100 in the spinal surgery described above (see the second figure from the right in Figure 2).

[0062] To achieve this state, the operator rotates the operating member 40 in the A1 direction from the state shown in Figure 8. As a result, the inner member 10 moves in the B1 direction, and the protruding pin 203 (see Figure 4) engages with the third groove portion 14c (see Figure 5) of the groove 14. The inner member 10 then moves linearly in the B1 direction (without rotation around the axis) along the axial direction, which is the extension direction of the groove 14. As a result of this movement in the B1 direction, if the first surface portion 102a of the spinal cage 100 comes into contact with the angle regulating surface 202h of the outer tip portion 202d, the spinal cage 100 is fixed at a position rotated 80° from a predetermined reference position by this contact. At this time, the mark M on the inner member 10 coincides with the third scale line L3 on the side of the opening 210.

[0063] Figure 11 shows a state in which the spinal cage 100 is restricted to a rotation angle of 40° (an example of a third angle θ3) around the engagement hole 103 from a predetermined reference position. This state is necessary, for example, in the process between the insertion start state and the insertion completion state in spinal surgery (see the second figure from the left in Figure 2).

[0064] To achieve this state, the operator rotates the operating member 40 in the A1 direction from the state shown in Figure 8. As a result, the inner member 10 moves in the B1 direction, and the protruding pin 203 (see Figure 4) engages with the third groove portion 14c of the groove 14 (see Figure 5). The inner member 10 then moves linearly in the B1 direction (without rotation around the axis) along the axial direction, which is the extension direction of the groove 14. As a result of this movement in the B1 direction, if the corner portion 102A of the spinal cage 100 is located within the angle-regulating recess 202g of the outer tip portion 202d (in other words, if the corner portion 102A engages with a part of the angle-regulating recess 202g), the spinal cage 100 is fixed at a rotation angle of 40° from a predetermined reference position (an example of a third angle θ3). At this time, the mark M on the inner member 10 coincides with the third scale line L3 on the side of the opening 210.

[0065] Here, the opening end of the angle-restricting recess 202g has a first edge 202m that abuts the first surface portion 102a when the corner portion 102A of the spine cage 100 is located within the angle-restricting recess 202g, and a second edge 202n that abuts the second surface portion 102b. The spine cage 100 is restrained by these first edge 202m and second edge 202n so that it cannot pivot around the engagement hole 103 as a fulcrum. At this time, it is preferable that the first edge 202m and the second edge 202n are in the same position in the axial direction of the outer member 20 (in the D3 direction). Furthermore, it is preferable that the first edge 202m and the second edge 202n are at the same distance from the axis of the inner member 10 when viewed from the D2 direction (the direction perpendicular to the plane of the paper in Figure 11). In other words, when viewed from the D2 direction (the direction perpendicular to the plane of the paper in Figure 11), it is preferable that the axis of the inner member 10 passes through the midpoint of the line segment connecting the first edge 202m and the second edge 202n. The first edge 202m and the second edge 202n do not necessarily have to be edges; for example, the first edge 202m may be replaced with a chamfered shape that can make surface contact with the first surface portion 102a, or the second edge 202n may be replaced with a chamfered shape that can make surface contact with the second surface portion 102b.

[0066] [summary] As described above, in this embodiment, the inserter 1 comprises a hollow outer member 20 having an outer tip portion 202d, and an inner member 10 having an inner tip portion 13 having an engagement plate portion 13a that can engage with the engagement hole 103 of the spinal cage 100, and which penetrates the outer member 20 in its axial direction and is movable along the axial direction. The inner member 10 is movable between a first position in which the spinal cage 100 is positioned away from the outer tip portion 202d when the engagement plate portion 13a engages with the engagement hole 103 of the spinal cage 100, and a second position in which the spinal cage 100 is positioned in contact with the outer tip portion 202d. The outer tip portion 202d has an angle restricting surface 202h and an angle restricting recess 202g that restrict the rotation angle of the spinal cage 100 around the engagement hole 103 from a predetermined reference position when the inner member 10 is in the second position. The angle restricting surface 202h restricts the rotation angle to a first angle θ1 (for example, 0°) when the first surface portion 102a of the spine cage 100 comes into contact with the angle restricting surface 202h when the inner member 10 is moved from the first position to the second position while engaged, and restricts the rotation angle to a second angle θ2 (for example, 80°) when the second surface portion 102b comes into contact with the angle restricting surface 202h. The angle restricting recess 202g is a recess that opens into the angle restricting surface 202h when viewed from the thickness direction of the spine cage 100. The angle-restricting recess 202g restricts the rotation angle to a third angle θ3 (for example, 40°) between the first angle θ1 and the second angle θ2 when the inner member 10 is moved from the first position to the second position while engaged, and the corner 102A where the first surface 102a and the second surface 102b of the spine cage 100 intersect is located within the angle-restricting recess 202g.

[0067] This configuration allows the rotation angle of the spinal cage 100 to be fixed at three angles: a first angle θ1, a second angle θ2, and a third angle θ3, without employing a complex configuration such as a gear mechanism. Therefore, the installation work when placing the spinal cage 100 between two vertebral bodies V can be simplified. In other words, in a spinal cage system without an angle-regulating recess 202g, the rotation angle of the spinal cage 100 can only be fixed at two angles: the first angle θ1 and the second angle θ2. However, with the above configuration, by moving the inner member 10 from the first position to the second position so that the corner portion 102A of the spinal cage 100 is located within the angle-regulating recess 202g, the rotation angle of the spinal cage 100 can also be fixed at a third angle θ3 (for example, 40°) between the first angle θ1 and the second angle θ2. Therefore, the variation in the rotation angle of the spinal cage 100 that can be fixed by the inner member 10 increases, allowing the surgeon to, for example, push the spinal cage 100 between the two vertebral bodies V while fixing it at the third angle θ3 during the intermediate step in Figure 2 (see the second figure from the left in Figure 2). Thus, the installation work of the spinal cage 100 can be made easier.

[0068] Furthermore, in this embodiment, the spinal cage 100 has a guide recess 105 that opens across the first surface 102a and the second surface 102b. The outer tip 202d protrudes outward from the angle restricting surface 202h in the axial direction of the outer member 20 and has a guide projection 202i that can engage with the guide recess 105 of the spinal cage 100. The guide projection 202i engages with the guide recess 105 when the inner member 10 is engaged.

[0069] With this configuration, during the insertion of the spinal cage 100, the guide projection 202i of the outer member 20 engages with the guide recess 105 of the spinal cage 100, thereby reducing the possibility of the spinal cage 100 swaying in the thickness direction during rotation. As a result, the surgeon can insert the spinal cage 100 between the two vertebral bodies V in a stable position.

[0070] Furthermore, in this embodiment, the first surface portion 102a and the second surface portion 102b are continuously connected via a third surface portion 102c, which is a substantially arc-shaped curved surface when viewed from the thickness direction.

[0071] With this configuration, the corner portion 102A located at the boundary between the first surface portion 102a and the second surface portion 102b has a curved shape rather than a sharp shape. Therefore, even if the corner portion 102A comes into contact with the entrance portion of the angle-restricting recess 202g (for example, the first edge 202m or the second edge 202n) when it enters the angle-restricting recess 202g of the outer tip portion 202d, the possibility of the corner portion 102A chipping is reduced.

[0072] In this embodiment, the predetermined angle α, which is the intersection angle between the first surface portion 102a and the second surface portion 102b, is preferably 90° or more and 120° or less.

[0073] According to this, the possibility of the corner 102A of the spinal cage 100 becoming excessively sharp, and the possibility of difficulty in restricting the rotation angle of the spinal cage 100 by the angle-restricting recess 22g can be reduced. That is, if the predetermined angle α is set to less than 90°, the second angle θ2 (=180°-α) will exceed 90°, but considering the insertion direction of the inner member 10 with workability in mind, a configuration in which the second angle θ2 exceeds 90° may not be necessary. Therefore, in the above configuration, by setting the second angle θ2 to 90° or more, the possibility of the corner 102A of the spinal cage 100 becoming unnecessarily sharp is reduced in order to address such cases where it is not necessary. On the other hand, if the predetermined angle α is set to an angle exceeding 120°, the surface spanning the first surface 102a and the second surface 102b will become closer to a plane, making it difficult for the corner 102A to enter the angle-restricting recess 22g. Consequently, it may become difficult to restrict the rotation angle of the spine cage 100 (restriction to the third angle θ3) by the angle-restricting recess 22g, but with the above configuration, this possibility can be reduced by setting the predetermined angle α to 120° or more.

[0074] In this embodiment, the first angle θ1 (0° in this example), the second angle θ2 (80° in this example), and the third angle θ3 (40° in this example) satisfy the following relationship, Equation 1.

[0075] θ3 = (θ1 + θ2) / 2 ... (Equation 1) With this configuration, the spinal cage 100 can be fixed at a third angle θ3, which is the midpoint between the first angle θ1 and the second angle θ2. Therefore, the possibility of the third angle θ3 being biased to either a greater or lesser side relative to the midpoint between the first angle θ1 and the second angle θ2 can be reduced.

[0076] In this embodiment, the angle-restricting recess 202g has a bottom portion 202k located at the end opposite to the opening side in the recess direction. The depth Z of the angle-restricting recess 202g in the recess direction (see Figures 6A and 6B) is such that the corner portion 102A of the spine cage 100 does not come into contact with the bottom portion 202k when the corner portion 102A of the spine cage 100 is located within the angle-restricting recess 202g and the rotation angle of the spine cage 100 is restricted to a third angle θ3.

[0077] With this configuration, when the corner 102A of the spinal cage 100 is located within the angle-restricting recess 202g, the spinal cage 100 does not interfere with the bottom 202k of the angle-restricting recess 202g. Therefore, the possibility that the function of fixing the rotation angle of the spinal cage 100 by the angle-restricting recess 202g will be impaired due to interference between the spinal cage 100 and the bottom 202k can be reduced.

[0078] In this embodiment, the inserter 1 has a protruding pin 203 that protrudes radially inward from the outer member 20. The inner member 10 is rotatable between a first rotational position in which an engaged state can be achieved and a second rotational position in which an unengaged state can be achieved. The inner member 10 has a groove 14 on its outer circumferential surface that engages with the protruding pin 203. The groove 14 has a shape that allows the inner member 10 to move axially in conjunction with the rotational movement of the inner member 10 between the first rotational position and the second rotational position. The inner member 10 has a visible mark M on its outer circumferential surface. The outer member 20 has an opening 210 that exposes the mark M to the outside when the inner member 10 is in both the first rotational position and the second rotational position.

[0079] With this configuration, as the inner member 10 rotates between the first rotation position and the second rotation position, the inner member 10 moves in the axial direction. Therefore, by visually observing the position of the mark M on the outer surface of the inner member 10 through the opening 210, the operator can easily recognize whether the inner member 10 is in the first rotation position or the second rotation position, or in other words, whether the inner member 10 is in an engaged state, where it is engaged with the spinal cage 100, or in an unengaged state, where the engagement has been released.

[0080] Furthermore, in this embodiment, the axial position of the inner member 10 relative to the outer member 20 is the same in all states: the first state in which the rotation angle of the spine cage 100 is restricted to a first angle θ1 by the angle restricting surface 202h of the outer tip portion 202d; the second state in which the rotation angle of the spine cage 100 is restricted to a second angle θ2 by the angle restricting surface 202h; and the third state in which the rotation angle of the spine cage 100 is restricted to a third angle θ3 by the angle restricting recess 202g of the outer tip portion 202d. The opening 210 allows the mark M to be exposed to the outside in all states, including the first, second, and third states.

[0081] With this configuration, the position of the inner member 10 remains the same in all three states: the first state (the state in Figure 9), the second state (the state in Figure 10), and the third state (the state in Figure 11). Therefore, the position of the mark M on the outer surface of the inner member 10 also remains the same. Consequently, the position of the mark M does not differ for each of the first to third states, which would increase the number of scale lines needed to confirm the position of the mark M unnecessarily and potentially cause confusion in the operator's state recognition.

[0082] In this embodiment, the inner member 10 is movable along the axial direction between a first position and a second position when engaged.

[0083] With this configuration, the configuration of the inserter 1 can be simplified by switching between a first position in which the spinal cage 100 is positioned away from the outer tip portion 202d and a second position in which the spinal cage 100 is positioned in contact with the outer tip portion 202d, by moving the inner member 10 along the axial direction.

[0084] In this embodiment, the inserter 1 further comprises an operating member 40 connected to the inner member 10. The inner member 10 is capable of switching between an engaged state, in which the engaging plate portion 13a of the inner tip portion 13 engages with the engagement hole 103 of the spinal cage 100, and an unengaged state, in conjunction with the rotational operation of the operating member 40 performed around the axis of the inner member 10.

[0085] With this configuration, the engaged state and the disengaged state can be switched by a simple operation of rotating the operating member 40.

[0086] In this embodiment, the inner member 10 is switchable between an engaged state in which the engaging plate portion 13a engages with the engaging hole 103 of the spinal cage 100 and an unengaged state in which the engagement is released.

[0087] With this configuration, the spinal cage 100 can be attached to and detached from the inner member 10 by selectively switching the inner member 10 between an engaged state and an unengaged state. Therefore, the surgeon can attach and detach the spinal cage via the inner member 10 without directly touching the spinal cage 100.

[0088] [Other embodiments] The spinal cage system S according to an embodiment of this disclosure has been described above, but this disclosure is not limited thereto.

[0089] (1) In the above embodiment, as an example in which the corner portion 102A of the spinal cage 100 is located within the angle-restricting recess 202g, an example in which a part of the corner portion 102A engages with the angle-restricting recess 202g was described, but the embodiment is not limited to this. That is, the entire corner portion 102A may engage with the angle-restricting recess 202g. In this case, the angle-restricting recess 202g may have, for example, a substantially V-shape that fits with the corner portion 102A.

[0090] (2) In the above embodiment, the spinal cage system S was described as an example in which the rotation angle of the spinal cage 100 can be restricted to one of a first angle θ1, a second angle θ2, and a third angle θ3, but it is not limited to this. For example, there may be multiple third angles θ3.

[0091] (3) In the above embodiment, an example was described in which the engaging portion of the inner tip portion 13 is an engaging plate portion 13a and the engaged portion of the spinal cage 100 is an engaged hole 103, but the embodiment is not limited to this. For example, the engaging portion of the inner tip portion 13 may be a hole, and the engaged portion of the spinal cage 100 may be a protrusion that can engage with the hole. In other words, the engaging portion of the inner tip portion 13 and the engaged portion of the spinal cage 100 may be configured in any way as long as they can engage with each other.

[0092] (4) In the above embodiment, the outer member 20 is composed of multiple members, but it is not limited to this and may be composed of a single member (for example, an integrally molded product).

[0093] (5) In the above embodiment, the inner member 10 is composed of one member, but it is not limited to this and may be composed of multiple members.

[0094] (6) In the above embodiment, the spinal cage 100 has a plurality of protrusions 101a on its surface, but is not limited thereto. The spinal cage 100 may have a configuration that does not have a plurality of protrusions 101a. The spinal cage 100 may have a porous structure on its surface.

[0095] (7) In the above embodiment, an example was described in which the angle restricting surface 202h can restrict the rotation angle of the spine cage 100 to a first angle θ1 and a second angle θ2, and the angle restricting recess 202g can restrict the rotation angle of the spine cage 100 to a third angle θ3. However, in this disclosure, the restriction of the rotation angle is not limited to a state in which the rotation angle of the spine cage 100 is completely fixed and does not move. That is, the angle restricting surface 202h and the angle restricting recess 202g may restrict the rotation angle of the spine cage 100 to the extent that it can vary within a range of some play (e.g., 2 to 3°) when subjected to an external force.

[0096] (8) In the above embodiment, the first surface portion 102a and the second surface portion 102b are not directly connected but are indirectly connected via the third surface portion 102c. In this case, the first surface portion 102a and the second surface portion 102b do not directly intersect, but their respective extended surfaces intersect (in other words, they intersect spatially). The technical scope of this disclosure also includes configurations in which the first surface portion 102a and the second surface portion 102b do not directly intersect. In this case, the corner portion 102A where the first surface portion 102a and the second surface portion 102b intersect is near the boundary between the first surface portion 102a and the second surface portion 102b and is not strictly distinguished. In other words, the corner 102A where the first surface 102a and the second surface 102b intersect may, for example, include the entirety of the third surface 102c, or it may include a part of the third surface 102c, or it may include a part of the first surface 102a and a part of the second surface 102b in addition to the third surface 102c. Furthermore, the shape of the corner 102A may be any shape, such as a polygon or a curved surface.

[0097] (9) In the above embodiment, the first surface portion 102a and the second surface portion 102b may be directly connected without the third surface portion 102c. In this case, the first surface portion 102a and the second surface portion 102b will intersect directly. In this case, the corner where the first surface portion 102a and the second surface portion 102b intersect is the portion that includes the intersection position of the first surface portion 102a and the second surface portion 102b, and is not strictly defined. [Explanation of Symbols]

[0098] α :Predetermined angle θ1: 1st angle θ2: 2nd angle θ3: 3rd angle M: Mark S: Spinal cage system Z: Depth 1: Inserter 10: Inner component 13: Inner tip 13a: Engaging plate portion (engaging portion) 14: Groove 15: Recess 20: Outer component 22g: Angle-regulating recess 30: Male threaded component 30a: Outer surface 40: Operating component 100: Vertebral cage 102: Side view 102A: Corner 102a: First surface part 102b: Second surface part 103: Engaged hole (engaged part) 105: Guide recess 110: First end 120: 2nd end 202d: Outer tip 202g: Angle-regulating recess 202h:Angle regulation surface 202i: Guide convex part 202k: bottom 203: Protruding pin 210: Opening

Claims

1. A spinal cage having a first end and a second end spaced apart in a predetermined direction, a first surface and a second surface located adjacent to each other and intersecting at a predetermined angle at the first end, and an engaging portion located at the first end, The system includes an inserter that engages with the aforementioned spinal cage, The inserter is, A hollow outer member having an outer tip, The inner member has an engaging portion that can engage with the engaged portion of the spinal cage, penetrates the outer member, and is movable inside the outer member, The inner member is movable between a separated position, which positions the spinal cage apart from the outer tip, and a contact position, which positions the spinal cage in contact with the outer tip, when the engaging portion is engaged with the engaged portion of the spinal cage. The outer tip portion has an angle-regulating surface and an angle-regulating recess that restrict the rotational angle of the spine cage from a predetermined reference position to the engaged portion when the inner member is in the contact position, The angle restricting surface restricts the rotation angle to a first angle when the first surface of the spine cage comes into contact with the angle restricting surface when the inner member is moved from the separated position to the contact position while engaged with the spine cage, and restricts the rotation angle to a second angle when the second surface comes into contact with the angle restricting surface. The angle-restricting recess is a recess opening into the angle-restricting surface, and when the inner member is moved from the separated position to the contact position while engaged with the spinal cage, if the corner where the first surface and the second surface of the spinal cage intersect is located within the angle-restricting recess, the rotation angle is restricted to a third angle between the first angle and the second angle in a spinal cage system.

2. In the spinal cage system according to claim 1, The vertebral cage has guide recesses that open across the first and second surfaces, The outer tip portion has a guide projection that protrudes outward from the angle restricting surface in the axial direction of the outer member and is capable of engaging with the guide recess of the spinal cage. The spinal cage system wherein the guide projection engages with the guide recess when the inner member is engaged with the spinal cage.

3. In the spinal cage system according to claim 1 or 2, A spinal cage system in which the first surface and the second surface are continuously connected via a substantially arc-shaped curved surface when viewed from the thickness direction of the spinal cage.

4. In the spinal cage system according to claim 1 or 2, A spinal cage system in which the predetermined angle is 90° or more and 120° or less.

5. In the spinal cage system according to claim 1 or 2, Let the first angle be θ1, the second angle be θ2, and the third angle be θ3. The third angle θ3 satisfies the following relationship in the spinal cage system. θ3=(θ1+θ2) / 2...(Formula 1)

6. In the spinal cage system according to claim 1 or 2, The angle-regulating recess has a bottom portion located at the end opposite to the opening side in the direction of the recess, A spinal cage system in which the depth of the angle-restricting recess in the direction of the recess is such that the corner of the spinal cage does not come into contact with the bottom when the corner is located within the angle-restricting recess and the rotation angle is restricted to the third angle.

7. In the spinal cage system according to claim 1 or 2, The outer member further comprises a protruding pin that protrudes radially inward, The inner member is rotatable between a first rotational position capable of achieving the engaged state and a second rotational position capable of achieving the disengaged state. The inner member has a groove on its outer circumferential surface that engages with the protruding pin, The groove has a shape that allows the inner member to move in the axial direction in conjunction with the rotational movement of the inner member between the first rotational position and the second rotational position. The inner member has a visible mark on its outer surface. A spinal cage system wherein the outer member has an opening that exposes the mark to the outside when the inner member is in both the first rotation position and the second rotation position.

8. In the spinal cage system according to claim 1 or 2, The axial position of the inner member relative to the outer member is the same in all three states: the first state in which the rotation angle of the spine cage is restricted to the first angle by the angle restricting surface at the tip of the outer member; the second state in which the rotation angle of the spine cage is restricted to the second angle by the angle restricting surface; and the third state in which the rotation angle of the spine cage is restricted to the third angle by the angle restricting recess at the tip of the outer member. The inner member has a visible mark on its outer surface. The spinal cage system wherein the outer member has an opening that exposes the mark to the outside in all states, the first state, the second state and the third state.

9. In the spinal cage system according to claim 1 or 2, A spinal cage system in which the inner member is movable along the axial direction between the separated position and the contact position in the engaged state.

10. In the spinal cage system according to claim 1 or 2, The inner member further comprises an operating member connected to the inner member, The spinal cage system wherein the inner member can switch between the engaged state and the disengaged state in conjunction with the rotational operation of the operating member performed around the axis of the inner member.

11. In the spinal cage system according to claim 1 or 2, The spinal cage system wherein the inner member is switchable between an engaged state in which the engaging portion engages with the engaged portion of the spinal cage and an unengaged state in which the engagement is released.

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