Connector device for connecting one or more rods of a spinal implant system

Abstract

A connector device (1) for connecting one or more rods (5, 6) of a spinal implant system is proposed, comprising a housing (2), an insert (3) and a fastening element (4) The housing (2) has an opening (20) for receiving a rod (5, 6). The insert (3) is configured to be positioned in the opening (20). The fastening element (4) serves for fastening the rod (5, 6) and the insert (3) in the opening (20). An outer surface (31) of the insert (3) forms one or more protrusions (310, 311) which are configured to engage with the boundary surface (21) that defines the opening (20) and / or the boundary surface (21) forms one or more protrusions which are configured to engage with the outer surface (31) of the insert (3), in order to prevent a relative movement between the insert (3) and the housing (2).

Description

[0001] TITLE

[0002] CONNECTOR DEVICE FOR CONNECTING ONE OR MORE RODS OF A SPINAL IMPLANT SYSTEM

[0003] TECHNICAL FIELD

[0004] The present invention relates to a connector device for connecting one or more rods of a spinal implant system. The spinal implant system can particularly be a pedicle screw system and the one or more rods can be connecting rods of the pedicle screw system.

[0005] PRIOR ART

[0006] Spinal implant systems are frequently used in medicine to bring vertebrae of the spine or parts of vertebrae into a desired position and hold them in this position, in order to stabilize the spine for example in the event of a malposition or after a fracture. Spinal implant systems include pedicle screw systems in which several pedicle screws, each anchored in a vertebral body, are usually fixed to a common connecting rod and thereby connected to each other. In order to connect several connecting rods of a spinal implant system, in particular of a pedicle screw system, to each other, connector devices are used. Depending on whether the rods are connected axially one behind the other or parallel to each other, such a connector device is referred to as an axial connector or a parallel connector. Connector devices are also used in spine implant systems to e.g. connect a rod to a screw head.

[0007] With respect to both axial and parallel connectors, but also with respect to other connector devices, it is often desirable for the physician to have a certain amount of freedom in fixating the rod in different polyaxial orientations relative to the other rod or component, depending on the needs of the surgery and of the patient.

[0008] A connector device of a spinal implant system is for example disclosed in US 2019 / 0388125 A1. The connector device comprises a main body that forms a space, into which a rod can be inserted and fastened by means of a fixing screw. In order to be able to fix the rod in various three-dimensionally pivoted positions in the base body, an insert in the form of a flexible ring having a partially spherical outer surface is provided. The insert is arranged in the space of the main body with the rod accommodated in it.

[0009] WO 2005 / 099603 A1 discloses a rod connector with two housing components that are pressed together by means of a screw, in order to clamp two rods between them. A spherical bushing can be provided to allow one of the rods to move relative to the housing.

[0010] US 8,430,916 B1 discloses a connector device having a clamp-like compressible casing that serves to fixate two rods of an implant system to each other. In order to achieve uniform clamping and to allow the rod to be arranged at different angles to the casing, a ball-like insert with a partially spherical outer surface is provided. The insert comprises longitudinal slots to allow compression of the insert.

[0011] EP 3 406 212 A1 discloses a connector device for fastening a connecting rod to another rod, in which a bearing ring is inserted into a receiving opening of a housing, in order to clamp the rod. Also here, the insert, i.e. the bearing ring, allows the rod to be fixed in different polyaxial positions in relation to the housing and, thus, to the other rod.

[0012] WO 02 / 36026 A2 discloses a connector device for connecting a rod to a vertebral anchor is a spinal system. For this purpose, the rod is clamped in place via a slotted ring. The ring can have a recess on its outer surface to improve compressibility.

[0013] A connector of a spinal implant system is disclosed in US 2007 / 0282339 A1 , in which one of the rods to be connected to each other is arranged in a circumferentially closed opening in which a clamping device is provided. By screwing a clamping screw into the clamping device, the rod accommodated therein is pressed downwards against the clamping device and with it against the inner surfaces of the connector housing which forms the opening.

[0014] WO 2005 / 018490 A2 discloses a pedicle screw system in which a connecting rod is connected to the head of a pedicle screw by means of a nut screw that is screwed into an inner thread of the screw head. To allow the screw to be adjusted angularly relative to the rod on the one hand, but to keep this within certain limits, the rod is held in a ring-shaped insert which has a recess on its outer surface that is engaged by a pin attached to the screw head.

[0015] WO 2009 / 139969 A1 proposes to provide inwardly extending projections on an annular clamping element in order to prevent a relative movement of a non-metallic connecting rod of a pedicle screw system relative to the clamping element.

[0016] In EP 3 782 566 A1 , a connector device is shown, where a bushing is inserted in a first orientation into an opening of a connector housing, in order to be pivoted by 90° to a second orientation, in which the rod can be received. A pin attached to the housing and engaging an indentation at the outer side of the bushing serves to restrict the movement of the bushing relative to the connector housing.

[0017] With the connector devices of the state of the art, there is often a residual risk that the rod, together with the insert, might move relatively to the connector housing at some point during prolonged use, e.g. due to a jerky movement of the patient or an insufficiently tightened clamping screw. There is also a certain risk that the insert might be positioned in an incorrect orientation in the connector housing, which could likewise lead to an insufficient fixation and eventually even to an unwanted movement of the rod. Such a situation can occur, for example, if the slot of a C-shaped insert comes to rest in the area where the clamping screw should clamp the insert and thus the rod.

[0018] SUMMARY OF THE INVENTION

[0019] It is an object of the present invention to provide a connector device for connecting one or more rods of a spinal implant system, which largely prevents any unwanted movements of the rod(s) and preferably also ensures a correct assembly by the physician.

[0020] The object is solved by a connector device as claimed in claim 1. Further embodiments of the invention are laid down in the dependent claims.

[0021] Thus, the present invention provides a connector device for connecting one or more rods of a spinal implant system, comprising a housing having at least one opening which is defined by a continuous boundary surface of the housing and is configured to receive a rod; an insert having an inner surface and a continuous outer surface and is configured to be positioned in the opening between the boundary surface and the rod; and a fastening element for fastening the rod in the opening by exerting a pressure onto the outer surface of the insert.

[0022] The outer surface of the insert forms one or more protrusions which are configured to engage with the boundary surface of the housing and / or the boundary surface of the housing forms one or more protrusions which are configured to engage with the outer surface of the insert, in order to prevent a relative movement between the insert and the housing, when the rod is fastened in the opening by the fastening element.

[0023] Due to the engagement of the outer surface of the insert with the boundary surface of the housing by means of the one or more protrusions, an inadvertent movement of the insert relative to the housing can effectively by prevented. Thus, the connection between the insert and the housing is based not only on frictional force, but also on a positive fit. The mutual engagement of the insert and the housing by means of the one or more protrusions can also be used to ensure a correct insertion of the insert into the opening of the housing. For example, complementary recesses can be provided on the surface opposite the projections, which allow the insert to be inserted in only one predetermined orientation.

[0024] The connector preferably serves to connect two rods to each other. It can particularly be an axial connector or a parallel connector, in which case, however, the connected rods do not necessarily have to be exactly parallel to each other. Instead, it is preferable that the two rods can also run at an angle to each other, at least to a certain degree. The term parallel connector therefore only means that the two rods are arranged side by side at the connection point, as opposed to one behind the other, as in the case of an axial connector. In a preferred embodiment, the two rods are arranged at a distance of each other at the connection point.

[0025] Embodiments are also possible, however, in which the connector serves to connect a single rod only. The connector can for example serve to connect a rod to a screw, such as a bone screw and in particular a pedicle screw. In this case, the connector can itself form the screw, in particular the screw head. For example, the connector can be an offset connector that connects a rod to a screw.

[0026] The one or more rods are preferably connecting rods of a pedicle screw system, i.e. connecting rods that serve to connect one or more pedicle screws. Thus, the spinal implant system is preferably a pedicle screw system. The one or more rods are preferably each made as a whole in one piece. The material of which the one or more rods are made of is preferably a fiber-reinforced plastics material, such as a carbon fiber- re info reed plastics material, in particular carbon fiber- re info reed polyetheretherketone (PEEK).

[0027] The housing is preferably made as a whole in one piece. It can have one single opening for receiving a rod as well as the insert, which is configured to be arranged between the boundary surface of the opening and the rod. In a preferred embodiment, however, the housing has two or more openings, in particular exactly two openings which each serve to receive a rod. The openings are preferably each defined, i.e. delimited, by a continuous boundary surface. The continuous boundary surface preferably in each case completely encloses the respective opening, which means that the continuous boundary surface extends completely around the respective opening. To insert a rod into the corresponding opening, it must therefore preferably be inserted along its length. In some embodiments, however, it is also possible for the at least one opening to be open to the side, i.e. to not be entirely enclosed by the continuous boundary surface. While a laterally closed opening is usually well suited to achieve a particularly safe connection to the rod, a laterally open opening can have advantages for the physician during assembly and implantation of the spinal implant system.

[0028] A surface, in particular the boundary surface, is considered continuous if it has no interruptions, meaning that it is preferably made as a whole in one piece and advantageously from the same material. The continuous surface can have a structure with edges, grooves, protrusions and / or recesses. The continuous surface can also have one or more openings that are circumferentially delimited by the material that forms the surface or are open to the side. However, an element that can be removed non-destructively from the rest of the housing and is not firmly connected to the boundary surface does not usually form part of the boundary surface.

[0029] The at least one opening is preferably a round opening, in particular a circular opening. The size and shape of the opening preferably corresponds to the size and shape of the rod and / or of the insert that is received in the respective opening. If the housing has more than one opening for receiving a rod, the openings preferably all have the same size and shape. In some embodiments, however, it is also possible to have openings, that have different sizes and / or shapes, in order to receive and hold rods and / or inserts of differing cross- sectional sizes and / or shapes. In addition to the at least one opening for receiving a rod, the housing can have further apertures, openings and / or holes. The provision of one or more threaded holes, which are each intersecting with one of the opening(s) is even preferred, in order to be able to fasten the rod in the respective opening by means of a fastening element having an outer thread, such as a threaded nut. In this case, the rod is fastened in the opening by means of screwing the fastening element into the respective threaded hole of the housing. As a result, the fastening element exerts a pressure onto the outer surface of the insert and, via the latter, preferably onto the rod, such that the insert and / or the rod are pressed against the boundary surface of the housing and are thus clamped in place.

[0030] The fastening element is preferably made as a whole in one piece. According to a preferred embodiment, the fastening element is made from a metal, in particular from titanium. The advantage of titanium is that it is light, has high strength and is better suited to imaging processes than other metals.

[0031] The inner surface of the insert is preferably sized and shaped such that it corresponds to the cross-sectional size and advantageously shape of the rod. The outer surface of the insert is preferably sized and shaped such that it corresponds to size and advantageously shape of the boundary surface of the housing. Thus, the inner and outer diameter of the insert are preferably sized such, that the rod can be received in the insert and the insert (with the rod) can be received in the opening without creating large gaps between the rod and the insert and the insert and the housing.

[0032] The insert usually has an overall shape of a ring. In use, the ring-shaped insert is arranged within the opening and encloses at least partly or completely, the respective rod received in the opening. Thus, the insert is positioned in the opening between the rod and the boundary surface of the housing. According to a preferred embodiment, no further components are arranged in the opening.

[0033] According to a particularly preferred embodiment, the ring-shaped insert has a slot, meaning that it is as a whole C-shaped. A C-shaped insert is usually more flexible, which means that it can be better compressed, in order to be inserted into or removed from the opening, and / or expanded, in order to be positioned on a rod. The slot, which is advantageously through-going, preferably covers an angular area of 5° to 90°, in particular of 30 to 70°, of the ring. The one or more protrusions are preferably formed in one piece with the rest of the insert. According to a particularly preferred embodiment, the insert is made as a whole in one piece. It is preferably made from a metal, in particular from titanium.

[0034] The outer surface of the insert preferably forms a two-dimensionally extending part of a first spherical surface. By partially forming a spherical surface, the connector device can be designed such, that the insert can be tilted together with the rod in the opening in several directions, as long as it is not yet fastened by the fastening element. In a preferred embodiment, the connector device 1 is designed in such a way that the rods in the housing can be tilted so far that they enclose an angle of preferably 10° or more, in particular of 20° or more, between their respective longitudinal axes. Preferably, the connector device 1 is also designed such that the tiltability of the rods in the housing is limited, in particular limited such that the maximum angle enclosed by the longitudinal axes of the rods is limited to 20°, in particular to 30°. The limitation of the tilting of the rods in the housing can be, but does not need to be, directionally dependent. For example, the maximum horizontal tiltability of the rods can be the same or different as compared to their maximum vertical tiltability. In this way, the connector device enables rods to be connected in a variety of mutual orientations, allowing the spinal implant system to be optimally adapted to the patient's needs. In order to further facilitate the tilting of the insert in the opening and / or to prevent the insert from inadvertently falling out of the opening, it is preferred that the boundary surface of the housing forms a two-dimensionally extending part of a second spherical surface. The second spherical surface formed by the boundary surface preferably corresponds to the first spherical surface formed by the insert with regard to its diameter and size. In this way, the insert can be tilted to several sides, while still being safely hold within the opening by the boundary surface.

[0035] If the one or more protrusions are formed by the outer surface of the insert, they can be serrated, in order to be pressed into the material of the housing and in this way engage with the boundary surface. If the one or more protrusions are formed by the boundary surface of the housing, they can likewise be serrated, in order to be pressed into the material of the insert and in this way engage with the outer surface of the insert.

[0036] According to another, particularly preferred embodiment, however, the boundary surface of the housing forms one or more recesses, which are each configured to receive one of the one or more protrusions of the outer surface of the insert and / or the outer surface of the insert forms one or more recesses, which are each configured to receive one of the one or more protrusions of the boundary surface of the housing. Due to the one or more recesses, the insertion and removal of the insert into and out of the opening can be facilitated. The one or more recesses can also ensure a correct positioning of the insert in the opening. Furthermore, by providing one or more recesses, the movement, in particular the tilting, of the insert in the opening (when the fastening element is not yet fastened) can be defined in a constructional manner. At the same time, due to the positive fit, it can still be guaranteed that any movements of the insert relative to the housing are effectively prevented after fastening of the fastening element, in particular along the most heavily loaded directions of movement, such as longitudinal displacement or rotation of the rod relative to the housing.

[0037] In a preferred embodiment, at least one, preferably at least two of the one or more protrusions are arranged within a semicircle formed by the boundary surface in a cross- sectional view, which is arranged diametrically opposite the fastening element, when the insert is positioned in its intended position in the opening. In the cross-sectional view, at least two of the one or more protrusions are preferably arranged at a distance of 90° relative to each other, when the insert is positioned in its intended position in the opening. The arrangement of at least one of the protrusions within a semicircle arranged diametrically opposite the fastening element and / or of at least two of the protrusions at a distance of 90° relative to each other brings about the advantage that the respective protrusion or protrusions do not interfere with the fastening element when the latter is fastened. Also, by arranging two protrusions at an angle of 90° relative to each other, it is possible to enable a guided and precisely limited tilting movement of the insert relative to the housing in all directions. For this purpose, the one or more recesses are preferably provided in each case in the form of a groove. The one or more protrusions can then in each case be in the form of an engaging web, wherein the length, shape and / or size of the web can be chosen such in relation to the length, shape and / or size of the respective groove that a tilting of the insert relative to the housing in a corresponding direction is disabled or enabled, and, if enabled, limited as desired.

[0038] In a particularly preferred embodiment, the boundary surface of the housing forms an undercut for the insert, which hinders removal of the insert from the opening. The undercut can particularly be formed by an annular groove provided by the boundary surface. The undercut preferably prevents removal of the insert from the opening, while the physician inserts the rod and adjusts the tilting angle of the rod and the insert relative to the housing before he fastens the fastening element, in order to fix the insert and, thus, the rod it its position. Due to the undercut, a removal of the insert from the opening is preferably only possible, if the insert is sufficiently compressed, which is advantageously only possible, if no rod is received in the insert. For inserting the insert into its intended position in the opening, the insert preferably needs to be compressed, in order to overcome the undercut. Such a compression of the insert is advantageously only possible, if the respective rod is not arranged in the insert.

[0039] According to a further development of the invention, the inner surface of the insert forms one or more protrusions which are configured to engage with the rod, in order to prevent a relative movement between the insert and the rod, when the rod is fastened in the opening by the fastening element. The one or more protrusions that are formed by the inner surface of the insert are preferably configured to be pressed into the material, preferably the plastics material, of the rod and in this way engage with the rod. In this way, the rod can be fixed in the insert at any longitudinal and rotational position. For this purpose, the one or more protrusions that are formed by the inner surface of the insert can particularly be serrated and / or in the form of cutting edge. Having protrusions that are in the form of an elongated cutting edge instead of a dot-shaped serration has the advantage that a displacement and / or rotation of the rod in a direction perpendicular to the cutting edge can be prevented in a particularly effective way.

[0040] In a preferred embodiment, a first such elongated protrusion extends along a circumferential direction of the opening, in order to prevent a longitudinal displacement of the rod in the opening. Alternatively or, what is preferred, in addition, a second elongated protrusion can be formed by the inner surface of the insert, that extends along a longitudinal direction of the opening, in order to prevent a rotation movement of the rod in the opening. The first and the second elongated protrusions as mentioned are preferably arranged on diametrically opposite sides of the insert with respect to the rod, wherein one of them is advantageously arranged in the region where the outer surface of the insert is contacted by the fastening element, when the latter is fastened in the intended use of the connector device. In this way, the clamping force exerted onto the insert by the fastening element, can be used to press the one or more protrusions into the rod.

[0041] The material of which the housing is made of is preferably a fiber-reinforced plastics material, such as a carbon fiber- re info reed plastics material, in particular carbon fiber- reinforced polyetheretherketone (PEEK). Fiber-reinforced plastic and in particular carbon fiber-reinforced PEEK has the advantage that it is light, has high strength and is does not lead to artifacts in medical imaging processes, such as computer tomography (CT) or magnetic resonance imaging (MRI).

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,

[0044] Fig. 1 shows an oblique perspective view of a connector device according to the invention, in the form of a parallel connector, with two parallel rods being connected by the connector device;

[0045] Fig. 2 shows a top view of the connector device and the rods of Fig. 1 ;

[0046] Fig. 3 shows a top view of the connector device of Fig. 1 , with two oblique rods being connected by the connector device;

[0047] Fig. 4 shows a lateral view of the connector device and the rod of Fig. 3;

[0048] Fig. 5 shows an oblique perspective explosion view of the connector device and the rods of Fig. 1 ;

[0049] Fig. 6 shows a central cross-sectional view through the connector device and the rods of Fig. 1 ;

[0050] Fig. 7 shows a front view of the connector device and the rods of Fig. 1 ;

[0051] Fig. 8 shows a central cross-sectional view through the housing of the connector device of Fig. 1 ;

[0052] Fig. 9 shows a front view of the housing of the connector device of Fig. 1 ;

[0053] Fig. 10 shows a top view of the housing of the connector device of Fig. 1 ;

[0054] Fig. 11 shows a cross-sectional view of the housing of the connector device of Fig. 1 onto the plane XI-XI as marked in Fig. 10;

[0055] Fig. 12 shows an enlarged front view of one of the inserts of the connector device of Fig. 1 ;

[0056] Fig. 13 shows a side view of the insert of Fig. 12 from the viewing direction marked with

[0057] XIII in Fig. 12;

[0058] Fig. 14 shows a side view of the insert of Fig. 12 from the viewing direction marked with

[0059] XIV in Fig. 12;

[0060] Fig. 15 shows a central cross-sectional view through a housing of a connector device according to another inventive embodiment;

[0061] Fig. 16 shows a central cross-sectional view through the connector device according to a further inventive embodiment;

[0062] Fig. 17 shows a front view of one of the inserts of the connector device of Fig. 16;

[0063] Fig. 18 shows an oblique perspective view of a connector device according to the invention, in the form of an axial connector;

[0064] Fig. 19 shows an oblique perspective explosion view of the connector device of Fig. 18; and

[0065] Fig. 20 shows a central cross-sectional view through the connector device of Fig. 18.

[0066] DESCRIPTION OF PREFERRED EMBODIMENTS

[0067] In Figures 1 to 20, a connector device 1 for connecting two rods of a spinal implant system as well as parts thereof are shown according to various preferred inventive embodiments. Elements having the same or a similar function are marked with the same reference sign in each case.

[0068] The connector device 1 according to the embodiment shown in Figures 1 to 17 is in the form of a parallel connector, i.e. a connector device 1 that serves to connect two rods 5, 6 to each other in such a way that they are arranged side by side to each other in the connection point, as it is shown in Figure 1. In the configuration shown in Figure 1 , the two rods 5, 6 are connected such by the connector device 1 that they extend in parallel.

[0069] As can be further seen from Figure 1 , the connector device 1 comprises a housing 2 that is made as a whole in one piece. The housing 2 has two through-going openings 20 that are arranged at a distance next to each other and extend in parallel. The housing 2 is preferably made from carbon fiber-reinforced polyetheretherketone (PEEK).

[0070] Each of the rods 5 and 6 is inserted lengthwise into one of the openings 20. In order to facilitate the insertion of the rods 5, 6, the openings 20 widen up on each side of the housing 2 towards the outside. The rods 5, 6 are each made of one piece and preferably from carbon fiber-reinforced PEEK. They preferably form part of a spinal implant system, in particular of a pedicle screw system.

[0071] In order to fix the rods 5 and 6 in their respective positions in each opening 20, fastening elements 4 are provided. Each fastening element 4 is associated with one opening 20 and thus serves to fasten one of the rods 5, 6. The fastening elements 4 are in each case in the form of a threaded nut that comprises an outer thread 40, as can e.g. be seen in Figures 5 and 6. The fastening elements 4 are each made as a whole in one piece and preferably from a metal, in particular from titanium. With their outer threads 40, the fastening elements

[0072] 4 are screwed into a threaded hole 22 that is provided on the housing 2. The two threaded holes 22 extend in parallel from the top surface of the housing 2 downwards such that they each intersect with one of the openings 20 (see e.g. Figure 8). Thus, by screwing one of the fastening elements 4 into a threaded hole 22, the rod 5 or 6 received by the respective opening 20 can be fastened, such as to be fixed in its position relative to the housing 2.

[0073] For screwing the fastening elements 4 into the threaded holes 22 by means of a tool or instrument not shown in the Figures, the fastening elements 4 each comprise an engaging structure 41 as can be seen in Figure 2. The engaging structure 41 can e.g. have a Torx- shape or any other suitable shape.

[0074] As can be better seen in e.g. Figures 5 and 6, the connector device 1 comprises inserts 3 which are arranged in each opening 20 and at least partially encompass the respective rod

[0075] 5 or 6. Each of the inserts 3 is positioned in one of the openings 20 between the rod 5 or 6 and a continuous boundary surface 21 of the housing 2 that circumferentially encloses and, thus, delimits the respective opening 20.

[0076] Each of the inserts 4 is as a whole C-shaped, as can be well seen from Figures 5, 6 and 12. The general ring-shape of the insert 3 is interrupted by a throughgoing slot 30, which here extends over an angular range of approximately 40° to 60°. Due to the slot 30, the insert 3 is compressible, in order to be inserted into the opening 20. The insert 3 has an outer surface 31 , which is radially directed outwards, and which, in the assembled state of the connector device 1 , is in contact with the boundary surface 21 of the housing 2. The insert 3 also comprises a radially inwardly directed inner surface 32, which, in the state, in which the connector device 1 connects the two rods 5 and 6, is in contact with one of the rods 5, 6. Thus, the insert 3 is configured in each case to be arranged in one of the openings 20 between the rod 5 or 6 and the boundary surface 21 of the housing 2. The fastening element 4 is in contact with the outer surface 31 of the insert 3 and, when fastened, exerts a pressure onto the insert which is transmitted onto the rod 5, 6. As a result, the rod 5, 6 is clamped in place within the insert 3 due to the pressure effected by the fastening element. The fastening element 4 presses the insert 3 including the rod 5 or 6 against the boundary surface 31 at the diametrically opposite side of the opening 20. As can be seen in Figures 5 and 11 , the boundary surface 21 forms an annular groove 210 which extends around the entire opening 20 in each case. Due to the annular groove 210, an undercut is formed for the insert 3, which hinders removal of the insert 3 from the opening 20. For inserting the insert 3 into the opening, the C-shaped insert 3 needs to be slightly compressed, in order to overcome the undercut due to the annular groove 210. Once the insert 3 is received by the annular groove 210, it expands and cannot be removed anymore from the opening 20 without being compressed. A compression of the insert 3 is, however, not possible, if one of the rods 5, 6 is received therein, which means that the insert 3 with the rod 5 or 6 is securely held in the opening 20.

[0077] The outer surface 31 of the insert 3 forms a two-dimensionally extending part of a convex first spherical surface. The spherical shape, i.e. the bending of the outer surface 31 of the insert 3 can for example be recognized at the top of Figure 14. A two-dimensionally extending part of a concave second spherical surface is formed by the boundary surface 21 of the housing 2. Due to these spherical surfaces, the insert 3 can be tilted in various directions to a certain degree with respect to the housing 2, in order to allow the rods 5, 6 to be connected in an oblique state, as it is shown in Figures 3 and 4. The connector device 1 can, for example, be designed in such a way that a certain horizontal pivoting of the rods

[0078] 5 and 6 in the housing 2 is possible, whereby this pivoting is restricted in such a way that the two rods 5, 6 enclose a maximum horizontal angle a of preferably 30° between their respective longitudinal axes (see Figure 3). Furthermore, the pivoting can be restricted in such a way that the two rods 5, 6 enclose a maximum vertical angle of preferably 30° between their respective longitudinal axes (see Figure 4). Due to the spherical shape of the outer surface 31 of the insert, the fastening element 4 can nevertheless exert a perpendicular force onto the insert 3, even if it is in such a tilted state. Thus, due to the first and second spherical surfaces, an effective clamping of the insert 3 and, thus, the rod 5 or

[0079] 6 in the connector device 1 can still be achieved.

[0080] In order to prevent a relative movement between the insert 3 and the housing 2, when the rod 5 or 6 is fastened in the opening 20 by the fastening element 4, first and second outer protrusions 310 and 311 are formed by the outer surface 31 of the insert 3. The boundary surface 21 of the housing forms first and second recesses 211 and 212 for the same purpose. The first and second recesses 211 and 212 are complementary with respect to protrusions 310 and 311. Thus, when inserting the inserts 3 into one of the openings 20 each, the protrusions 310 and 311 engage the recesses 211 and 212, such that a positive fit is achieved between the insert 3 and the housing 2. Due to this positive fit and in combination with the undercut formed by the annular groove 210, a relative movement of the insert 3 and the housing 2 is effectively prevented, when the rod 5 or 6 is fastened in the opening 20 by the respective fastening element 4: Due to the mutual engagement of the protrusions 310, 311 and the recesses 211 , 212, which extend longitudinally (at least partially) through the opening 20, a rotation of the rod 5, 6 relative to the housing 2 is made impossible. Due to the undercut formed by the annular groove 210, a longitudinal displacement of the rod 4, 6 relative to the housing is made impossible, if the fastening element 4 is fastened. Thus, it is here the combination of the positive fit between the protrusions 310, 311 and the recesses 211 , 211 on the one hand with the undercut formed by the annular groove 210 on the other hand, which effectively prevents any movement of the insert 3 relative to the housing 2.

[0081] In other embodiments, both rotations as well as longitudinal movements of the insert 3 relative to the housing 2 could effectively be prevented by means of protrusions and recesses, if these would be designed respectively. For example, the mutually engaging protrusions and recesses of the outer surface 31 of the insert 3 and of the boundary surface 21 of the housing 2 could form some sort of a bayonet catch with recesses, wherein each recess forms a groove curved at right angles. A large number of other variants are possible.

[0082] The protrusions 310, 311 and the recesses 211 , 212 also ensure a correct insertion of the inserts 3 into each opening 20. As it is shown in Figure 5, the inserts 3 can only be inserted in the respective opening 20 in the orientation as shown. In any different orientation, the protrusions 310, 311 and the recesses 211 , 212 are not able to engage with each other, which means that an insertion of the insert 3 into the opening 20 is effectively prevented. In Figure 11 , it can also be seen that the second recess 212 does not extend entirely through the opening 20. As a result, it is only possible to insert and remove the insert 3 into / from the opening 20 from one side of the housing 2.

[0083] The annular groove 210 is shaped complementary to the shape of the outer surface 31 of the insert 3 and thus forms an undercut, so that not only a removal of the insert 3 from the opening 20 is prevented, but also a tilting of the insert relative to the housing 2. In order to nevertheless enable a tilting, the boundary surface 21 of the housing 2 forms an indentation 213, which intersects the annular groove 210. The indentation 213 can for example be seen in Figures 5, 9 and 11. By selecting the arrangement, shape and size of the recess 213, the degrees of freedom with regard to the tilting movement of the insert 3 relative to the housing 2 can be precisely defined. Figures 13 and 14 show the slightly differing shapes and dimensions of the first outer protrusion 310 and the second outer protrusion 311. By means of the shapes and dimensions of the protrusions 310 and 311 , the angular extent of the tilting can be limited in a targeted and well-defined manner. By providing different shapes and dimensions, the angular extent of the tilting can even be limited depending on the direction of the tilting.

[0084] In order to prevent a movement of the rods 5 and 6 relative to the respective insert 3 after implantation of the connector device 1 and in particular during prolonged use, protrusions in the form of a circumferential cutting edge 320 and a longitudinal cutting edge 321 are formed by the inner surface 32 of the insert 3. See for example Figures 5, 6 and 12 in this respect. The circumferential cutting edge 320 and the longitudinal cutting edge 321 are configured to engage with the rod 5 or 6, when the fastening element 4 is fastened, in order to form a positive fit and to thereby prevent any movement of the rod 5,6. When screwing the fastening element 4 into the threaded hole 22 of the housing 2, a pressure is exerted onto the insert 3, which causes the cutting edges 320 and 321 to be pressed into the fiber- reinforced plastic material of the respective rod 5 or 6.

[0085] The circumferential cutting edge 320 extends along the circumferential direction of the insert 3 and, thus, of the rod 5 or 6, when the latter is received in the insert 3 and in the opening 20. As a result, the circumferential cutting edge 320 mainly serves to prevent a longitudinal displacement of the rod 5 or 6 relative to the housing 2. The longitudinal cutting edge 321 , on the other hand, extends along the longitudinal direction of the insert 3 and, thus, of the rod 5 or 6. As a result, the longitudinal cutting edge 321 mainly serves to prevent the rod 5 or 6 from rotating in the opening 20 of the housing 2. Due to the engagement of the cutting edges 320 and 321 with the rod 5 or 6, a movement of the rod 5, 6 relative to the insert 3 is effectively prevented also with regard to a prolonged use of the connector device 1.

[0086] Figure 15 shows an embodiment of a housing 2 of an inventive connector device 1 , where the first recess 211 and the second recess 212 are arranged in the respective opening 20 at slightly different angular positions, as compared to the embodiment shown in Figure 8. The two recesses 211 and 212 are here also arranged at a distance of 90° relative to each other in each case, but none of them is arranged directly diametrically opposite of the respective threaded hole 22. However, as can be seen in the cross-sectional view of Figure 15, in each opening 20, both recesses 211 and 212 are arranged within a semicircle formed by the boundary surface 21 , which is arranged diametrically opposite the threaded hole 22. In other words, both recesses 211 and 212 are arranged within an angular range of 180° that is positioned diametrically opposite of the respective threaded hole 22. Furthermore, it can be seen that here the annular groove 210 does not extend symmetrically around the center of each of the openings 20, but is slightly offset thereto, which can e.g. serve to define and delimit the movability of the insert 3 within the respective opening 20.

[0087] Figures 16 and 17 show an embodiment, where the boundary surface 21 of the housing 2 forms a first protrusion 214 and a second protrusion 215 and the outer surface 31 of the insert 3 forms a first recess 312 and a second recess 313. The protrusions 214, 215 are configured to engage with the recesses 312, 313, in order to prevent a relative movement between the inset 3 and the housing 2, when the rods are fastened in the openings 20 by means of the fastening element 4.

[0088] Figures 18 to 20 show an embodiment of an inventive connector device 1 in the form of an axial connector, i.e. a connector device 1 that serves to connect two rods to each other in such a way that they are arranged in parallel and side-by-side to each other when viewed from a cross-section, or one behind the other when viewed from the side. The two rods can particularly be connected such by the axial connector that so that they extend parallel to, and in the same direction when connected to each other.

[0089] As can be further seen from Figures 18-20, the connector device 1 comprises a housing 2 that is made as a whole in one piece and preferably from carbon fiber- re info reed polyetheretherketone (PEEK). The housing 2 has two openings 20 that are arranged side- by-side at a distance from one another such that one opening is behind the other from a side view. Each opening 20 allows the insertion of a free end of a rod.

[0090] In order to facilitate the insertion of the rods, the openings 20 widen up on each side of the housing 2 towards the outside. In order to fix the rods 5 and 6 in their respective positions, fastening elements 4 in the form of threaded nuts are provided. With their outer threads 40, the fastening elements 4 are screwed into threaded holes 22 which extend in parallel from the top surface of the housing 2 downwards such that they each intersect with one of the openings 20.

[0091] An insert s is arranged in each opening 20, in order to be positioned between the continuous boundary surface 21 of the respective opening 20 and the rod. In analogy to the previous embodiments, the inserts 3 are compressible due to their C-shape with a slot 30, in order to be insertable into the respective opening 20.

[0092] As can be seen from Figure 20, the openings 20 as well as the inserts 3 have different diameters, in order to be adapted for receiving rods of different diameters.

[0093] The design of the inserts 3 of the embodiment of Figures 18 to 20 is generally the same as the one of the previous embodiments, with the difference that the smaller insert 3 comprises two circumferential cutting edges 320 that are arranged in parallel at a distance from each other. Both inserts 3 comprise first and second outer protrusions 310 and 311 for engagement with a respective recess 211 or 212 provided in the boundary surface 21 of the respective opening 20 of the housing 2, similar as in the embodiments of Figures 1 to 14. Also in the embodiment of Figures 18 to 20, the boundary surface 21 comprises an annular groove 210 in each case that forms an undercut for the respective insert 3. An indentation 213 is further provided which intersects with the annular groove 210 and serves to enable a tilting of the insert 3 including the rod relative to the housing 2.

[0094] The present invention is not limited to the embodiments as described and shown. Instead, a large variety of modifications is possible. For example, the connector device 1 does not necessarily need to be in the form of a parallel connector or in the form of an axial connector, but could instead also be in the form of a transverse connector or even be configured to connect a single rod only. For example, connector may also be an offset connector, a bypass connector, or even a crosslink or cross connector. The protrusions formed by the boundary surface 21 could also be designed and / or arranged differently. There could be a single protrusion only or more than two protrusions. The preformed recesses 211 and 212 of the boundary surface 21 are not absolutely necessary. It would also be conceivable, that the protrusions formed by the outer surface 31 are pressed into the material of the housing 2 in a similar way as the cutting edges 320, 321 are pressed into the rod 5 or 6, when the fastening element 4 is fastened. The fastening element does not need to be in the form of a threaded nut, but could instead be formed by any other element that is able to exert a pressure onto the outer surface 31 of the insert 3. For example, bayonet- or latchingstructures could be provided for connecting the fastening element to the housing 2. A large variety of further modifications is possible. LIST OF REFERENCE SIGNS

[0095] 1 Connector device

[0096] 2 Housing

[0097] 20 Opening

[0098] 21 Boundary surface

[0099] 210 Annular groove

[0100] 211 First recess

[0101] 212 Second recess

[0102] 213 Indentation

[0103] 214 Frist protrusion

[0104] 215 Second protrusion

[0105] 22 Threaded hole

[0106] 3 Insert

[0107] 30 Slot

[0108] 31 Outer surface

[0109] 310 First outer protrusion

[0110] 311 Second outer protrusion

[0111] 312 First recess

[0112] 313 Second recess

[0113] 32 Inner surface

[0114] 320 Circumferential cutting edge

[0115] 321 Longitudinal cutting edge

[0116] 4 Fastening element

[0117] 40 Outer thread

[0118] 41 Engaging structure

[0119] 5 Rod

[0120] 6 Rod a Horizontal angle

[0121] P Vertical angle

Claims

CLAIMS1. A connector device (1) for connecting one or more rods (5, 6) of a spinal implant system, comprising a housing (2) having at least one opening (20) which is defined by a continuous boundary surface (21) of the housing (2) and is configured to receive a rod (5, 6); an insert (3) having an inner surface (32) and a continuous outer surface (31) and is configured to be positioned in the opening (20) between the boundary surface (21) and the rod (5, 6); and a fastening element (4) for fastening the rod (5, 6) in the opening (20) by exerting a pressure onto the outer surface (31) of the insert (3), characterized in that the outer surface (31) of the insert (3) forms one or more protrusions (310, 311) which are configured to engage with the boundary surface (21) of the housing (2) and / or the boundary surface (21) of the housing (2) forms one or more protrusions which are configured to engage with the outer surface (31) of the insert (3), in order to prevent a relative movement between the insert (3) and the housing (2), when the rod (5, 6) is fastened in the opening (20) by the fastening element (4).

2. The connector device (1) of claim 1 , wherein the outer surface (31) of the insert (3) forms a two-dimensionally extending part of a first spherical surface, and wherein the boundary surface (21) of the housing (2) preferably forms a two-dimensionally extending part of a second spherical surface.

3. The connector device (1) of claim 1 or 2, wherein the insert (3) as a whole is C-shaped.

4. The connector device (1) as claimed in any of the preceding claims, wherein the boundary surface (21) completely encloses the opening (20), and wherein the housing (2) as a whole is preferably made in one piece.

5. The connector device (1) as claimed in any of the preceding claims, wherein the boundary surface (21) of the housing (2) forms one or more recesses(211 , 212), which are each configured to receive one of the one or more protrusions (310, 311) of the outer surface (31) of the insert (3) and / or the outer surface (31) of the insert (3) forms one or more recesses, which are each configured to receive one of the one or more protrusions of the boundary surface (21) of the housing (2).

6. The connector device (1) as claimed in any of the preceding claims, wherein at least one, preferably at least two of the one or more protrusions (310, 311) are arranged within a semicircle formed by the boundary surface (21) in a cross-sectional view, which is arranged diametrically opposite the fastening element (4), when the insert (3) is positioned in its intended position in the opening (20).

7. The connector device (1) as claimed in any of the preceding claims, wherein, in a cross-sectional view, at least two of the one of the one or more protrusions (310, 311) are arranged at a distance of 90° relative to each other, when the insert (3) is positioned in its intended position in the opening (20).

8. The connector device (1) as claimed in one of claims 5 to 7, wherein the one or more protrusions (310, 311) and the one or more recesses (211 , 212) are designed such, that a correct positioning of the insert (3) in the opening (20) relative to the fastening element (4) is ensured.

9. The connector device (1) as claimed in one of claims 5 to 8, wherein the one or more protrusions (310, 311) and the one or more recesses (211 , 212) are designed such, that a tilting of the insert (3) relative to the housing (2) is enabled, but limited, when the fastening element (4) is not fastened.

10. The connector device (1) as claimed in any of the preceding claims, wherein the boundary surface (21) of the housing (2) forms an undercut (210) for the insert (3), which hinders removal of the insert (3) from the opening (20).11 . The connector device (1) as claimed in any of the preceding claims, wherein the inner surface (32) of the insert (3) forms one or more protrusions (320, 321) which are configured to engage with the rod (5, 6), in order to preventa relative movement between the insert (3) and the rod (5, 6), when the rod (5, 6) is fastened in the opening (20) by the fastening element (4).

12. The connector device (1) as claimed in claim 11 , wherein a first protrusion (320) extends along a circumferential direction of the opening (20), in order to prevent a longitudinal displacement of the rod (5, 6) in the opening (20), and wherein a second protrusion (321) extends along a longitudinal direction of the opening (20), in order to prevent a rotation of the rod (5, 6) in the opening (20).

13. The connector device (1) as claimed in any of the preceding claims, wherein the housing (2) is made from a fiber- re info reed plastics material, and / or wherein the insert (3) is made from a metal, in particular from titanium.

14. The connector device (1) as claimed in any of the preceding claims, wherein the fastening element (4) has an outer thread (40) with which it can be screwed into the housing (2).

15. The connector device (1) as claimed in any of the preceding claims, wherein the fastening element (4) is made from a metal, in particular from titanium.

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