MODULAR SUPPORT CAGE

Description

Field of the invention

[0001] The invention relates to a modular support cage for supporting vertebral elements. State of the art

[0002] In cases of disc damage, so-called vertebral cages are used to support the vertebral elements. These are inserted between the individual vertebral elements to support the spine, replacing the damaged disc. To ensure the most natural position of the individual vertebral elements relative to one another, the lordosis of the spine is to be replicated. Since the vertebral elements are spaced further apart at the front than at the back, such a vertebral cage should also be thicker at the front to maintain the natural spacing between the vertebral elements. In this case, however, the vertebral cages cannot be inserted from behind through the back; instead, they must be surgically inserted through the abdominal wall.Because the front of the vertebral cage is designed with a larger spacing, and the vertebral elements on the back cannot be pushed apart to this distance, the vertebral cage does not fit through the gap between the adjacent vertebral elements. Alternatively, a smaller vertebral cage can be used for insertion from the back, but this would not achieve the ideal spacing between the vertebrae and the desired lordosis.

[0003] Such a ventral vertebral cage is described, for example, in US Pat. No. 6,562,074 B2. Therein, an adjustable bone fusion implant is disclosed comprising a first plate having an inner surface with a plurality of spaced-apart first support elements projecting therefrom. Each support element has a plurality of projecting teeth. A second plate has an inner surface with a plurality of spaced-apart second support elements projecting from the second plate. Each second support element has at least one tooth or adjustment hole formed thereon. A portion of the plurality of teeth of each first support element mechanically engages the at least one tooth or adjustment hole of a corresponding second support element such that the first plate and the second plate can be selectively separated to form a chamber therebetween.A reinforcing element is arranged between the first plate and the second plate such that the application of a compressive force between the first plate and the second plate exerts compression on the reinforcing element.

[0004] US 2018 / 0071102 A1 discloses a mountable implant comprising two or more elements that can be positioned at a certain distance from each other and are held together by one or more biocompatible pins to form a graft unit. Description of the invention

[0005] The object of the invention is therefore to provide a vertebral cage that can be implanted minimally invasively from the back of the patient, regardless of the lordosis. This object is achieved by a modular support cage according to claim 1.

[0006] A modular support cage according to the invention for supporting vertebral elements comprises a distal support section which has at least two opposite end plates which can be moved relative to one another, wherein each end plate comprises a contact region which is directed outwards and is designed for contact with the element to be supported, and a bearing region which is directed towards an opposite end plate, and a proximal support section which has at least two outwards-directed contact regions and a bearing element which can be inserted between the bearing regions of the end plates and supports them, so that the end plates are held in a predetermined position.By dividing the system into separate front and rear elements, it is possible to first push the distal support section, which is further away from the user, into position through the narrow gap between the vertebral elements and only then position the proximal support section. To do this, the end plates of the first support section are pressed apart, for example with a tool, or moved apart in some other way so that the contact areas of the end plates have an inclination and position that supports the vertebral elements in their natural lordosis. The bearing element is then pushed between the spaced-apart end plates to hold them in the adjusted position. Therefore, when inserted between the vertebrae, the distal support section requires no more space than the proximal support section, and the modular support cage can be implanted from the back for any lordosis.The bearing element is therefore arranged in the final position between the first contact areas. Furthermore, "distal" means a position directed away from the user of the support cage, and "proximal" means a position closer to the user, where the user is the person handling the support cage. Furthermore, "modular" in the sense of the invention means a separate division into a front (distal) and a rear (proximal) part, and not a separation of the support sections into top and bottom (although a top / bottom separation is also provided in the embodiment according to the invention, at least for the distal support element, in order to be able to adjust the lordosis).

[0007] Preferably, the contact areas of the distal and proximal support sections are aligned with one another and, in particular, form a common plane. This means that the edges of the first and second support sections facing one another are in a continuous, continuous plane and, in particular, also have the same gradient, thus exhibiting no bend in the surface (kinkless). This ensures uniform support of the vertebral elements and ensures a sufficiently large support surface for the entire element.

[0008] The contact areas and the bearing element of the proximal support section are preferably formed as a single piece. This facilitates handling and increases stability and safety when inserting the proximal support section.

[0009] Furthermore, at least one of the two endplates can be designed with a tapered thickness, so that the contact area has a particularly continuous incline; however, preferably all endplates have such a tapered thickness. The tapered thickness also preferably applies to the proximal support section. A design with a tapered thickness reliably provides the desired lordosis. A solid design or a design with a trabecular structure can improve the stability of the support sections.

[0010] The end plates preferably have a stop, in particular a receiving recess at their distal end, which serves as a stop for the bearing element. This allows the end position of the bearing element to be precisely determined and accidental mispositioning can be reliably prevented. A receiving recess additionally secures the end plates against accidental detachment from the bearing element.

[0011] Preferably, the bearing element and the bearing areas have stepped elements at the interface between the distal and proximal support sections. This prevents lateral pivoting of the support sections in the end position and ensures correct alignment. Such a stepped section can also be used, in particular, as a stop for the insertion direction. Furthermore, a second receiving recess can also be formed at the distal end of the contact areas, into which the proximal end of the end plates engages, thus ensuring the cohesion of the end plate to the bearing element.

[0012] The at least two outwardly directed contact areas of the proximal support section preferably each comprise two spaced-apart surfaces, and the at least two outwardly directed contact areas of the distal support sections are preferably each U-shaped. This makes it easy to handle the tools for the two support sections without them interfering with each other.

[0013] The support cage preferably comprises an anchoring of a bearing element and a support section, so that the support cage can be used more reliably. Preferably, the support cage comprises at least one support section having at least two opposing support plates movable relative to one another, each support plate comprising a contact area directed outward and designed for contact with the element to be supported, a bearing area directed toward an opposing support plate, and a bearing element insertable between the support plates and supporting them, so that the support plates are held in a predetermined position.The bearing element and the support sections of the support cage or the modular support cage further comprise mutually complementary locking elements at the distal end region, which interact in the end position of the bearing element such that the bearing element is connected to the support sections in a movement-proof manner.

[0014] The locking elements (e.g. spring pin and bore) can of course also be used with the previous embodiment, which has the distal and proximal support sections, so that there too the bearing element and the support sections of the support cage or the modular support cage can further have mutually complementary locking elements at the distal end region, which interact in the end position of the bearing element such that the bearing element is connected to the support sections in a movement-proof manner.

[0015] The locking element ensures in a simple way that after the lumbar support has been adjusted and the bearing element has been inserted to fix the support sections, the bearing element can no longer be moved.

[0016] The locking elements are preferably designed as a spring-driven pin and a receptacle. This design enables reliable release of the locking element when the end position is reached. The spring-driven pin is preferably located on the bearing element, and the receptacle is preferably located on the bearing areas of the support sections. This ensures that the locking element is easily accessible and can be reached for release.

[0017] The end plates of the distal support section can have a tool holder, which is particularly designed as a bore. Such a tool holder facilitates handling when inserting the proximal support section. The bore is preferably circular, which makes the orientation of the tool to be inserted irrelevant and facilitates insertion into the tool holder. However, it can also be oval or polygonal (e.g., triangular, square, or hexagonal), which ensures the alignment of the tool. Short description of the characters

[0018] Figure 1 shows an isometric view of the modular support cage in an assembled state; Figures 2a and 2b show isometric views of the modular support cage with auxiliary tools during insertion of the proximal support section into the distal support section; Figure 3 shows a cross-section through the locking element in the distal support section; Figures 4a and 4bshow a longitudinal section through the locking element in the distal support section in the open and locked state; and Figures 5a and 5b show isometric views of the proximal side (back) of the support sections. Description of the preferred embodiments

[0019] In Figure 1 An assembled modular support cage 10 is shown in an isometric view. The support cage comprises a distal support section 20 and a proximal support section 40.

[0020] In the present embodiment, the distal support section 20 is formed in two parts and comprises at least two end plates 22a, 22b. These end plates 22a, 22b each have a contact surface 24a, 24b which is directed outwards (in Figure 1upwards or downwards) and which, during use, is in contact with the adjacent vertebral elements. On the side opposite the contact surfaces 22a, 22b, bearing regions 26a, 26b are provided, which serve for support on a bearing element 44, so that the end plates 22a, 22b are held in the end position by the bearing element. The end plates 22a, 22b are preferably formed in one piece and more preferably are U-shaped, with the two spaced-apart side arms 25a, 25b extending proximally, i.e., towards the user, and the connecting web 25c, which connects both side arms 25a, 25b, being provided at the distal end of the end plates 22a, 22b. The end plates 22a, 22b are formed with a tapered thickness so that the contact surface 24a, 24b slopes from the proximal end to the distal end (at the connecting web 25c), with the end plates 22a, 22b being thinner at the proximal end and becoming thicker towards the distal end.However, the inclination of the contact surfaces 24a, 24b can also be achieved by only one of the end plates 22a, 22b being designed with a tapered thickness, wherein the taper should then be correspondingly stronger.

[0021] The end plates 22a, 22b preferably have a stop 30, which can be designed, for example, as a simple step element. Furthermore, a receiving engagement 28a, 28b can be provided at the distal end of the end plates 22a, 22b, which, after engagement with the bearing element 44 described later, holds the end plate 22a, 22b firmly on the bearing element 44. This receiving engagement 28a, 28b is preferably also used as a stop.

[0022] Furthermore, the end plates have bearing areas 26a, 26b on the inwardly directed side (opposite the contact surfaces) which interact with the bearing element 44. Guide steps are preferably provided on these bearing areas 26a, 26b, which Figure 2acan be seen. These interact with the stepped sections 62 in the holding tools 60 and thus securely guide the holding tools 60. Furthermore, tool holders 32a, 32b can also be formed on the end plates 22a, 22b, into which the holding tools 60 can be inserted and which, in particular together with the guide steps, can ensure secure holding of the end plates 22a, 22b. The tool holder 32a, 32b can, in principle, have any desired design, e.g., oval or polygonal; however, a circular bore is the preferred design for the tool holder.

[0023] The proximal support section 40 has a contact section 41 on which the upper and lower contact surfaces 42a, 42b are formed, which, during use, are in contact with the vertebral elements. Furthermore, the proximal support section 40 comprises a bearing element 44 extending in the distal direction, which is placed between the end sections 22a, 22b of the distal support section 20 and is in contact with the bearing areas 24a, 24b at the top and bottom, respectively. The bearing element 44 is preferably formed integrally with the contact section 41. Furthermore, it is possible for the bearing element 44 to be formed with a tapered thickness, so that the bearing element 44 becomes thinner towards the distal end. This tapering is then compensated for by a corresponding thickening of the end plates 22a, 22b in order to still maintain the correct lordosis.The taper serves to assist the pushing apart of the end plates 22a, 22b by means of the holding tool 60 by inserting the bearing element 44.

[0024] The proximal support section 40 is preferably U-shaped, so that the contact surfaces 42a, 42b are each provided as two spaced-apart surfaces on a side arm, and a connecting web connects these side arms at the distal end. The bearing element 44 extends distally in the center of the connecting web. A connecting web 56 can also be formed at the proximal end of the contact section, connecting and stabilizing the two side arms. The connecting web 56 further includes a recess or through-bore 54 through which the insertion tool 70 can be guided to the tool holder 50.

[0025] Furthermore, the proximal support section 40 can also have a receiving engagement 46, which is preferably provided at the distal end of the contact surfaces 44a, 44b, where the contact surfaces 44a, 44b and the contact surfaces 24a, 24b preferably meet. Here, the receiving engagement 46 is formed as a triangular undercut into which a triangular projection 27 of the contact surfaces 24a, 24b of the distal support section 20 is inserted, thus firmly holding the latter on the bearing element 44.

[0026] For the insertion tool 70, the proximal support section 40 has a tool holder 62 at its proximal end, which can in principle be designed like the tool holder in the distal support section 20 (circular, oval, polygonal). In a preferred embodiment, it is designed as a bore. The tool holder 50 preferably extends as far as a locking mechanism and thus enables the insertion tool 70 to interact with the locking mechanism. In this context, the U-shape described above is also a great advantage, because the distance between the side arms allows the tool holder 70 of the connecting web to be arranged as close as possible to the locking mechanism described later, and the locking mechanism can be handled more easily during preparation.

[0027] At the distal end of the proximal support section 40, engagement projections 48a, 48b are further preferably formed, which cooperate with the receiving engagements 28a, 28b in order to hold both support sections 20, 40 together.

[0028] The contact surfaces 22a, 22b, 42a, 42b of the support sections preferably have a pattern. This pattern can, for example, comprise transverse ribs or other elevations such as simple protrusions. In the embodiment shown, the pattern is depicted as triangular (jagged) ribs, which are particularly designed as steps adapted to the lordosis, so that the upper side of the steps is almost horizontal and the front sides are almost vertical (with an inclination of less than 10°).

[0029] In the Figures 2a and 2bIt shows how the proximal and distal support sections are pushed together. First, the holding tools 60 with the stepped section 62 are placed on the corresponding guide rail of the end plates 22a, 22b and then inserted into the tool holder 34a, 34b. The distal support section is then positioned between the vertebrae. The holding tools 60 shown in the figures can, for example, be the ends of a pair of pliers, with which the end plates 22a, 22b of the distal support section 20 can be pushed apart. Figure 2a The end plates 22a, 22b are already shown in a spaced-apart position, in which the correct lordosis is set. Furthermore, it can be seen how the insertion tool 70 is prepared for insertion into the proximal support section 40.

[0030] In Figure 2bThe proximal support section 40 has then been displaced toward the distal support section 20, so that the bearing element 44 is located between the end plates 22a, 22b and contacts and supports their bearing areas 26a, 26b. Upon pushing together, the engagement projections 48a, 48b at the distal end of the support cage, if present, have moved into the receiving recesses 28a, 28b. The same has happened at the junction of the contact surfaces 24a, 24b, 44a, 44b, where the receiving recess 46 has slid over the projection 27.

[0031] In this position, a locking mechanism can be provided in the modular support cage, which firmly and, in particular, irreversibly connects the bearing element 44 to the end plates 22a, 22b. Such a locking mechanism can also be used in a non-modular support cage (no separation into distal and proximal), which then has two support sections formed integrally at both the top and bottom from a proximal and a distal support section. In addition, there is then a bearing element that is inserted between the end plates of the distal support section and supports them, analogous to the bearing element 44 that supports the distal support section 20. This embodiment is not shown in the figures, but the locking mechanism functions in the same way as the locking mechanism for the modular support cage explained below.

[0032] The locking mechanism preferably comprises two locking elements, which here are preferably designed as a spring-driven locking block 49a, 49b and a locking receptacle 39a, 39b, whereby the term locking block also includes a design as a locking pin or locking ball. In the present embodiment, the spring-driven locking block 49 is arranged in the bearing element 44 and the locking receptacle 39 is arranged in the end plates 22a, 22b. However, the spring-driven locking block 49 can also be arranged conversely in the end plates 22a, 22b and the locking receptacle in the bearing element 44. The locking block 49a, 49b is preloaded with a spring that presses the locking block towards the end plate 22a, 22b. Here, one or more springs 53 are provided for both locking blocks 49a, 49b, which can preload both locking blocks 49a, 49b simultaneously in the opposite direction. In particular, only one spring can actually be provided.The locking blocks 49a, 49b are thus held within the bearing element 44 until the locking receptacle is reached and are then pressed into the locking receptacle by the spring 53.

[0033] To avoid the need to laboriously hold the locking blocks 49a, 49b in the bearing element with a tool until the locking blocks 49a, 49b are clamped under the end plates 22a, 22b, locking recesses 52 are preferably provided in the locking blocks 49a, 49b, which interact with the holding projections 72 of the insertion tool 70. Here, the locking blocks 49a, 49b are pressed together from the outside against the spring, and then the holding projections 72 of the insertion tool 70 are inserted first into the tool holder 50 of the proximal support section 40 and then into the locking recesses 52. Because the springs press the locking blocks 49a, 49b outward, the locking recesses 52 clamp with the holding projections 82 and improve their hold. Only when the proximal support section 40 is actually in the end position, the locking blocks 49a, 49b lie under the corresponding receptacles 39a, 39b.The insertion tool is then withdrawn from the tool holder 50, thus removing the retaining projections 72 from the locking recesses 52. As a result, the preloaded springs press into the locking receptacles 39a, 39b, and the locking blocks 49a, 49b fix the bearing element 44 in the end plates, so that withdrawal is no longer possible without removing the locking blocks from the locking receptacles.

[0034] Figure 5a shows a view of an assembled modular support cage 10. From this view, the tool holders 32a, 32b of the distal support section and the tool holder 50 of the proximal support section 40 are visible. The tool holder 50 of the proximal support section 40 is provided on the bearing element 44.

[0035] Preferably, a further bore 54 or a recess 54 is provided on a proximal reinforcing strut 56, which connects the contact surfaces 42a, 42b with the opposite contact surfaces 42a, 42b and thus stabilizes them.

[0036] In Figure 5b The distal support element 20 is shown in such a way that the tool holders 32a, 32b can be viewed from behind. The receiving recess 28a is also clearly visible. List of reference symbols

[0037] Modular support cage 10 Distal support section 20 End plate 22a, 22b Contact surface 24a, 24b Side arm 25a, 25b Connecting web 25c Bearing area 26a, 26b Projection 27 Receiving engagement 28a, 28b Stop 30 Tool receptacle 32a, 32b Latching receptacle 39a, 39b Proximal support section 40 Contact section 41 Contact surface 42a, 42b Bearing element 44 Receiving engagement 46 Spring 47a, 47b Engaging projection 48a, 48b Spring-driven latching block 49a, 49b Tool receptacle 50 Locking recesses 52 Spring 53 Through hole 54 Connecting web 56 Holding tool 60 Step section 62 Plug-in projection 64 Insertion tool 70 Holding projection 72

Claims

1. Modular support cage (10) for supporting vertebral elements, comprising: a distal support section (20) having at least two end plates (22a, 22b) which are opposite and movable relative to each other, one end plate (22a, 22b) each having an outwardly directed contact surface (24a, 24b) designed for contact with the element to be supported, and each having a bearing region (24a, 24b) directed toward an opposite end plate (22a, 22b); and a proximal support section (40) having at least two outwardly directed contact surfaces (42a, 42b) and a bearing element (44) which is insertable between the bearing areas (24a, 24b) of the end plates (22a, 22b) and bears these so that the end plates (22a, 22b) are held in a predetermined position.

2. Modular support cage (10) according to claim 1, wherein the contact surfaces (24a, 24b, 42a, 42b) of the distal and proximal support sections (20, 40) are aligned with each other.

3. Modular support cage (10) according to one of the preceding claims, wherein the contact surfaces (42a, 42b) and the bearing element (44) of the proximal support section (40) are designed in a single piece.

4. Modular support cage (10) according to one of the preceding claims, wherein the at least two end plates (22a, 22b) and / or at least part of the proximal support section (40) are designed with a tapered thickness so that the contact surfaces (24a, 24b, 42a, 42b) are inclined.

5. Modular support cage (10) according to one of the preceding claims, wherein the end plates (22a, 22b) have a stop for the bearing element (44).

6. Modular support cage (10) according to one of the preceding claims, wherein the bearing element (44) and the bearing areas (24a, 24b) have step elements (30) at the interface between the distal and proximal support sections (20, 40).

7. Modular support cage (10) according to one of the preceding claims, wherein the at least two outwardly directed contact areas of the proximal support section each have two spaced surfaces and the at least two outwardly directed contact areas of the distal support sections are each U-shaped.

8. Modular support cage (10) according to one of the preceding claims, wherein the bearing element (44) and the support plates of the support cage or the end plates (22a, 22b) of the modular support cage (10) further have complementary locking elements (39a, 39b, 49a, 49b) at a distal end region (39a, 39b, 49a, 49b) which, in the end position of the bearing element (44), interact in such a way that the bearing element (44) is fixed in terms of movement with the support sections or end plates (22a, 22b).

9. Support cage or modular support cage (10) according to claim 8, wherein the locking elements are designed as a spring-driven locking block (49a, 49b) and as a locking receptacle (39a, 39b).

10. Support cage or modular support cage (10) according to claim 9, wherein the spring-driven locking block (49a, 49b) is formed on the bearing element (44) and the locking receptacle (39a, 39b) is formed on the bearing areas (26a, 26b) of the end plates (22a, 22b).

11. Support cage or modular support cage (10) according to one of the preceding claims, wherein the end plates of the distal support section and / or the proximal support section have a tool receptacle (34a, 34b, 50).