Cervical cage

Abstract

Cage (20), which is designed as a disc replacement for the spine, in particular as a cervical disc replacement, wherein the cage (20) includes at least one receptacle (21) for attaching an application tool (40), and wherein the cage (20) comprises at least two through-holes (22a, 22b) for each anchoring screw (30), wherein a cap (10) is provided by means of which the passages (22a, 22b) for the anchoring screws (30) can be closed, characterized in that the cap (10) is designed as a threaded cap which is screwed into a thread (26a, 26b) of the passage (22a, 22b).

Description

Field of the invention

[0001] The invention relates to a cage designed as an intervertebral disc replacement for the spine. In particular, the invention relates to a cervical cage. Background of the invention

[0002] So-called cages are used for surgical spinal stabilization. These serve to stiffen two adjacent vertebral bodies and are inserted between the vertebrae in place of the intervertebral disc.

[0003] Such a cage is usually made of metal, especially titanium, or a plastic such as PEEK. To improve fixation, it is known to screw anchoring screws transversely through the cage into the vertebral bodies for cranial and caudal fixation.

[0004] Furthermore, the cage can be hollow inside so that it can be filled with a bone substitute material. This bone substitute material is usually a calcium phosphate material into which natural bone tissue can grow.

[0005] Document US 2008 / 0 249 569 A1 shows an implant with an attachable front plate. Document US 2012 / 0 232 599 A1 shows an implant with a fixation device. Document US 7 326 248 B2 shows an expandable implant with a closure cap. Object of the invention

[0006] Given the above-mentioned background, the invention is based on the object of providing a cage that can be used flexibly. In particular, it is an object of the invention to provide an improved cage that can be implanted optionally with or without anchoring screws. Summary of the invention

[0007] The object of the invention is already achieved by a cage with a cap according to claim 1.

[0008] Preferred embodiments and further developments of the invention can be found in the subject matter of the dependent claims, the description and the drawings.

[0009] The invention relates to a cage designed as an intervertebral disc replacement for the spine. In particular, the invention relates to a cage designed for cervical disc replacement.

[0010] The cage comprises at least one receptacle for attaching an application tool.

[0011] The receptacle can be designed, in particular, as a thread through which the cage can be connected to the application tool. The thread can be arranged, in particular, on a side wall, preferably on an anterior side wall of the cage.

[0012] The cage is held securely in place by the receptacle and can be inserted by the surgeon after resection of the intervertebral disc between the vertebrae.

[0013] The cage also includes two holes, each for an anchoring screw. These holes run diagonally from bottom to top and top to bottom through the cage, respectively, thus providing caudal and cranial anchorage.

[0014] The feedthroughs can include a thread. This allows them to be used in conjunction with anchoring screws, which have a head thread and thus provide a stable angle connection to the cage at the end of the screwing process.

[0015] According to the invention, the cage includes a cap by means of which the passages for the anchoring screws can be closed.

[0016] The caps can be used when the surgeon does not use anchoring screws. This allows for more flexible use of the cage.

[0017] Closing the holes for the anchoring screws also improves the introduction of bone replacement material into the cage.

[0018] The caps prevent bone replacement material from escaping laterally from the cage.

[0019] For example, the receptacle for the handling tool can serve as a connection for injecting bone substitute material. This can be designed, in particular, as a thread that extends into the at least partially hollow interior of the cage.

[0020] The caps block lateral leakage of the bone replacement material.

[0021] Furthermore, the apertures for the anchoring screws can also be used to inject bone substitute material. For example, one aperture can be closed with a cap, and the bone substitute material can be injected through the other. Bone substitute material can be introduced through the apertures, particularly above or below the cage. The cap is designed as a threaded cap. Preferably, the cap is designed as a grub screw. With such a grub screw, the screw drive extends through the thread as a blind hole.

[0022] When inserted, the cap should preferably protrude neither cranially nor caudally from the cage.

[0023] The cap preferably includes a conical thread. Such a conical thread has the advantage that the threads engage with each other over a short distance. The screwing-in process is thus quick and requires few turns.

[0024] In particular, the cage and cap can be designed in such a way that the cap can be fully screwed in with less than two turns, in particular with 0.3 to 0.5 turns.

[0025] The thread can in particular be designed as a single-turn thread.

[0026] The cap can, in particular, be truncated cone-shaped. In particular, the cone angle α can be between 50 and 30°.

[0027] The cap is preferably designed such that, when inserted, it extends through the passage but does not protrude from the passage.

[0028] In particular, it is provided that the cap, when inserted, comprises an inner edge that is flush with the underside or top of the cage. The inner edge, within the meaning of the invention, is in particular the distal edge of the cap, i.e., in particular, the distal edge of the grub screw.

[0029] When inserted, this edge is approximately at the level of the top or bottom of the cage.

[0030] An outer edge, on the other hand, is preferably flush with the side wall of the cage. This outer edge is particularly the proximal edge of the cap.

[0031] In this embodiment, the inserted cap extends over the maximum possible length. Furthermore, a cap with a relatively large diameter can be provided, which in turn makes it possible to provide passages for relatively large locking screws.

[0032] The passages can extend in particular at an angle cranially and / or caudally of 30 to 45° through the cage, relative to its mid-plane.

[0033] Furthermore, the feedthroughs can extend laterally at an angle of 5 to 15° to a central axis of the cage.

[0034] In one embodiment of the invention, the cage is made of printed titanium or a titanium alloy. The cage can be designed, in particular, as a cage. A mesh can extend at least partially over the top or bottom. Bone replacement material can penetrate the mesh. The mesh can, in particular, have the shape of a fabric, i.e., comprise loops that interlock or wrap around each other. However, these loops are not made of fabric, but of printed titanium or a printed titanium alloy.

[0035] According to a further aspect of the disclosure, this relates to a cage which is designed as an intervertebral disc replacement for the spine.

[0036] In particular, the disclosure relates to the cage described above. The cage has two passages that can be used, in particular, for the passage of anchoring screws.

[0037] According to this aspect, instead of a cap, a spike is provided which sits in at least one passage, preferably in both passages.

[0038] The spike comprises a shaft with a point. However, the shaft is not threaded. Instead, the shaft may contain barbs that anchor the spike in the bone tissue.

[0039] Preferably, the spike comprises a head thread that is screwed into the thread of the bushing. The thread can, as described above, be conical in particular.

[0040] In particular, the head of the spike can be designed like the cap described above.

[0041] The head thread allows the spike to be guided into the adjacent bone tissue and anchored much more quickly and easily than a screw.

[0042] The spike(s) can be pre-assembled in the cage. It is specifically designed so that, in the pre-assembled state, the spike tip does not protrude from the top or bottom of the cage. Only when the head thread is screwed in is the tip guided into the bone, thus anchoring the cage.

[0043] The invention further relates to a set comprising a cage and cap and / or cage as described above. The set further comprises an anchoring screw.

[0044] The screw may in particular have a thread with a shaft which is designed to be screwed into the adjacent vertebral body.

[0045] Furthermore, the anchoring screw preferably comprises a head with a head thread. The head thread can, in particular, correspond to the thread of the cap.

[0046] The anchoring screw is used instead of the cap if the surgeon wishes to anchor the cage caudally and cranially.

[0047] The set may further comprise an application tool with a handle that can be attached to the holder.

[0048] In particular, it can be an application tool in which the handle comprises a rod with a thread at the tip. The cage can be attached to the thread for insertion.

[0049] Furthermore, the set may comprise a cement applicator which can be connected to one of the feedthroughs and / or the receptacle in order to apply bone replacement material into the cage.

[0050] It is particularly provided that after the cage has been inserted by means of the application tool, the receptacle is connected to a channel, in particular a tube, through which the bone replacement material is applied into the interior of the cage.

[0051] When caps are used, these ensure that the bone replacement material does not leak out of the side wall of the cage.

[0052] Furthermore, the opening itself can also be used to apply bone replacement material.

[0053] In particular, the feedthrough can include lateral openings so that bone substitute material can enter the cage from the feedthrough. Furthermore, the bone substitute material can also flow above and below the cage via the feedthrough, where it penetrates the cage due to the grid-like structure of the top and bottom. Brief description of the drawings

[0054] The subject matter of the invention will be explained below with reference to an embodiment based on the drawings Fig. 1 to Fig. 12 will be explained in more detail. Fig. Figure 1 is a perspective view of a cage without caps inserted. Fig. 2 shows an anchoring screw. Fig. 3 shows a cap. Fig. 4 is a perspective view of the cage and cap. Fig. 5 is a central longitudinal section of the cage. Fig. 6 is a longitudinal section through a bushing. Fig. 7 is a longitudinal section with the cap now inserted. Fig. 8 is a perspective view of an application tool. Fig. 9 is a schematic representation of a cement applicator as may be part of a set according to the invention. Fig. Figure 10 illustrates how bone replacement material is introduced through a passage in the cage. Fig. 11 shows a spike. Fig. 12 is a sectional view of the cage with inserted spikes. Detailed description of the drawings

[0055] Fig. 1 shows a perspective view of a Cage 20.

[0056] The Cage 20 is designed as a cervical disc replacement.

[0057] This can in particular have a height of 3 to 10 mm (maximum height).

[0058] According to a preferred embodiment, the top side 25 and bottom side run not parallel, but diagonally to each other. These form a so-called lordosis angle. The lordosis angle can, for example, be between 2 and 8°.

[0059] The Cage 20 is made of a printed titanium alloy (e.g. manufactured using SLM).

[0060] The top 25 and bottom of the cage 20 are provided, at least in sections, with a lattice structure 27. This allows the top 25 and bottom to be permeable to bone replacement material. A cavity is located between them.

[0061] Furthermore, a web 28 extends approximately centrally over the cage 20. A web 28 extends on both the top side 25 and the bottom side, which serves for reinforcement.

[0062] The cage may further comprise spikes 29 on its top side 25 and / or bottom side, which press into the bone substance and thus improve the fixation of the cage 20.

[0063] The side wall 23 of the cage 20 includes a thread as a receptacle 21 for an application tool. This allows an application tool (see Fig. 8) into the Cage 20 and the cage can be placed.

[0064] For cranial and caudal anchoring using an anchoring screw (30 in Fig. 2) the cage 20 comprises passages 22a, 22b, which run diagonally through the cage 20 starting from the side wall.

[0065] The passages 22a, 22b each comprise a thread 26a, 26b, in which either the head of the locking screw is anchored or in which a cap (see Fig. 3) is used.

[0066] The passage 22a leads to the top side 25 and the passage 22b to the bottom side.

[0067] Fig. 2 shows a locking screw 30.

[0068] The locking screw 30 comprises a head with a head thread 31.

[0069] Extending from the head thread 31 is a shaft comprising a thread 32 that can be screwed into the bone substance. The locking screw 30 may comprise a self-tapping tip 33.

[0070] Instead of a locking screw 30, as in Fig. 2, the Fig. 3 shown cap 10 can be used.

[0071] The cap is frustoconical and includes a conical external thread 11. The underside 12 of the cap 10 is closed.

[0072] The external thread 11 preferably corresponds to the head thread of the locking screw (31 in Fig. 2).

[0073] The cap can have a diameter d (maximum diameter) of 3 to 8 mm, preferably 4 to 6 mm. The length l of the cap 10 can be 3 to 10 mm.

[0074] The cone angle α is preferably 15 to 30°.

[0075] Fig. 4 is a perspective view of the cage into which a cap 10 is now to be inserted.

[0076] The cap 10 is screwed into the thread 26b of the bushing 22b.

[0077] The cap 10 is designed as a grub screw and thus has a drive 13, which extends as a blind hole through the thread of the cap 10. The drive 13 can, for example, be designed as an internal spline.

[0078] The cap 13 is preferably made of a solid metal material, in particular of titanium or a titanium alloy.

[0079] Fig. 5 is a longitudinal section through the middle of the cage 10.

[0080] It can be seen that the receptacle 21 extends into the cage. Bone replacement material can be injected into the cavity between the top and bottom surfaces via the receptacle 21.

[0081] Fig. 6 is a longitudinal section of the cage in the area of ​​a passage 22b.

[0082] The passage 22b with the thread 26b can, as provided in another embodiment, comprise lateral openings 19 through which bone replacement material can enter the cage 20. The openings 19 are shown schematically in this view.

[0083] The thread 26b is conical. Due to the angled position of the passage 22b, the thread can only extend over a portion of the passage 22b. Preferably, the thread 26b extends from the top of the cage to its bottom.

[0084] Fig. 7 shows how a cap 10 is now screwed into a bushing 26a.

[0085] The cap 10 comprises an outer, proximal edge 15 which is approximately flush with the side wall of the cage 20.

[0086] The inner, distal edge 14 is approximately flush with the top or bottom of the cage 20.

[0087] Fig. 8 is a perspective view of an application tool 40. The application tool 40 comprises a handle 41 which comprises a rod 42, at the end of which a thread is arranged onto which the cage 20 can be screwed.

[0088] In this embodiment, the application tool 40 comprises a rod 42 on each side of the handle 41, to which a cage 20 can be attached.

[0089] The application tool 40 may further comprise a spacer 43.

[0090] The spacer 43 can optionally be inserted, particularly locked, into the rod 42. The spacer 43 prevents the cage 20 from being inserted too deeply between the vertebrae by resting against the adjacent vertebral body.

[0091] Fig. 9 shows a schematic representation of a cement applicator 50.

[0092] The cement applicator 50 comprises a handle 51, via which bone replacement material can be squeezed out, for example by pressing or turning.

[0093] The bone replacement material exits the cement applicator 50 via the channel 52, which is designed, for example, as a tube.

[0094] The channel 52 includes a thread 53 at its distal end.

[0095] This thread 53 can, for example, be screwed into the cage receptacle after the application tool has been unscrewed.

[0096] According to a further embodiment, the thread 53 can correspond to the external thread of the cap, whereby the passages can thus be used for applying bone replacement material.

[0097] Fig. 10 illustrates how bone replacement material is introduced through a passage 22a of the cage 20 by means of the cement applicator 50.

[0098] The cement applicator 50 is screwed into the passage 22a with the thread 53.

[0099] In this way, bone replacement material can be introduced, initially distributing primarily above or below the adjacent vertebra. This allows for height differences between the vertebra and the cage to be equalized, resulting in a more even pressure distribution.

[0100] Fig. 11 schematically shows a spike 16 which is provided instead of the cap according to a further aspect of the invention.

[0101] The spike 60 comprises a head thread 61, which can be designed in particular according to the cap described above.

[0102] However, the head end of the spike 60 is adjoined by a point 62, which is at the end of the shaft.

[0103] The shaft may be provided with barbs 63.

[0104] As in Fig. As shown in Figure 12, the spikes 60 can be screwed in using the head thread and anchor themselves in the cage 20.

[0105] The tip 62 of the respective spike 60 presses into the bone tissue and anchors the cage 20.

[0106] Compared to an anchoring screw, anchoring is faster. It's also conceivable to pre-assemble the spikes 60 in the cage 20, so that the tip 62 doesn't protrude when the cage 20 is inserted.

[0107] The invention made it possible to provide a cage that could be used flexibly. List of reference symbols 10 caps 11 external threads 12 Bottom 13 Drive 14 inner edge 15 outer edge 19 Opening 20 Cage 21 recording 22a, 22b Implementation 23 Side wall 24a, 24b corner 25 Top 26a, 26b thread 27 Lattice structure 28 jetty 29 top 30 anchoring screw 31 head thread 32 threads 33 self-tapping tips 40 application tools 41 Handle 42 bars 43 spacers 50 cement applicator 51 handle 52 channel 53 threads 60 Spike 61 head thread 62 lace 63 barbs

Claims

[1] Cage (20), which is designed as a disc replacement for the spine, in particular as a cervical disc replacement, wherein the cage (20) comprises at least one receptacle (21) for attaching an application tool (40), and wherein the cage (20) comprises at least two passages (22a, 22b) for one anchoring screw (30) each, wherein a cap (10) is provided, by means of which the passages (22a, 22b) for the anchoring screws (30) can be closed, characterized by that the cap (10) is designed as a threaded cap which is screwed into a thread (26a, 26b) of the bushing (22a, 22b). [2] Cage (20) according to the preceding claim, characterized by that the cap (10) comprises a conical thread (32). [3] Cage (20) according to one of the preceding claims, characterized by that the cap (10) is frustoconical, in particular with a cone angle α of 15 to 30°. [4] Cage (20) according to one of the preceding claims, characterized by that when a cap (10) is inserted, it comprises an inner edge (14) which is aligned with the underside (12) or top side (25) of the cage (20), wherein an outer edge (15) is aligned with the side wall of the cage (20). [5] Cage (20) according to one of the preceding claims, characterized by that the passages (22a, 22b) extend obliquely through the cage (20), in particular at an angle cranially and / or caudally of 30 to 45°, and / or that the passages are arranged laterally at an angle of 5 to 15° to the central axis. [6] Cage (20) according to one of the preceding claims, characterized by that the cage (20) is designed as a cage made of printed titanium or a titanium alloy. [7] Set with a cage (20) and cap (10) according to one of the preceding claims, further comprising at least one anchoring screw (30). [8] Set according to one of the preceding claims, further comprising a cement applicator (50) connectable to one of the passages (22a, 22b) in order to apply bone replacement material into the cage (20).

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