Medical bone connection device and method for connecting bones or bone parts
Patent Information
- Application Number
- PCT/EP2024/073011
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-08-25
- Filing Date
- 2024-08-15
- Publication Date
- 2025-03-06
Smart Images
Figure EP2024073011_06032025_PF_FP_ABST
Abstract
Description
[0001] TITLE
[0002] MEDICAL BONE JOINTING DEVICE AND METHOD FOR JOINTING BONES OR BONE PARTS
[0003] TECHNICAL FIELD
[0004] The present invention relates to a medical bone connection device, such as, in particular, a pedicle system, an axial or parallel connector system, a cervical plate system, or a vertebral body replacement. Furthermore, the present invention relates to a method for connecting two bones or bone parts using such a bone connection device.
[0005] STATE OF THE ART
[0006] Bone connection devices are frequently used in medicine to position and hold bones or bone fragments in a desired position, for example, after a fracture, such as a traumatic fracture, or in the event of a malalignment. Bone connection devices are particularly well-known in the form of spinal implant systems, which serve to connect and stabilize multiple vertebrae of the spine. These include pedicle systems, in which several pedicle screws, each anchored in a vertebral body, are fixed to a common connecting rod and thus connected to one another. Multiple connecting rods of a pedicle system, or connecting rods used to stabilize other bones or bone fragments, can be connected to one another via a connector.Depending on whether the rods are connected axially one behind the other or parallel next to each other, such a bone connection device is referred to as an axial connector or a parallel connector. Furthermore, bone connection devices in the form of cervical and lumbar plate systems are known, in which a connecting plate is fixed to several vertebrae of the cervical spine using screws to stabilize them. Another frequently used bone connection device is the vertebral body replacement, which serves to replace one or more defective vertebrae. The vertebral body replacement, which is often used in combination with a pedicle system, is connected to the adjacent vertebral bodies, with an expandable vertebral body replacement often being used to adapt to the gap to be filled.
[0007] Bone fusion devices are typically made of metal, such as titanium and / or a titanium alloy. Such bone fusion devices are radiopaque and allow the precise position of the implant (e.g., the pedicle screw) to be determined during a patient imaging examination, such as computed tomography (CT). Despite this advantage, such metal implants obstruct the view of the bone connected to the implant and the surrounding tissue during fluoroscopy because they are radiopaque. Furthermore, scattering effects occur during fluoroscopy, which in turn create artifacts in the area of the implant. Such metallic bone fusion devices also cause severe artifacts during magnetic resonance imaging (MRI).Due to their radiopacity, metallic bone fusion devices also impair radiotherapy for cancer patients, as the relatively large metallic mass causes scattering phenomena that reduce the effectiveness of the radiation, thus requiring a higher radiation dose, which in turn can cause side effects in the surrounding tissue.
[0008] To overcome these aforementioned disadvantages of metallic bone fusion devices, bone fusion devices made of non-metallic composite materials have been developed. Although the production of three-dimensional complex shapes from composite materials is challenging, it enables the production of radiotransparent components that do not exhibit these aforementioned disadvantages. Bone fusion devices made of non-metallic composite materials based on carbon fiber-reinforced polyetheretherketone (PEEK) are preferred in the market.
[0009] Bone connection devices, and in particular the types mentioned above, such as pedicle systems, connectors, plate systems, and expandable artificial vertebrae, typically comprise multiple connecting elements that must be secured together to fix the bones or bone parts. For example, in a pedicle system, the screws must be secured to the connecting rod, or in a connector, the connecting rods must be secured to a connector housing. To secure the at least two connecting elements of the bone connection device to one another, screw connections are commonly used in the prior art.
[0010] However, screw connections in components made of non-metallic composite materials have disadvantages. For example, producing precisely interlocking, and therefore easily interlocking, high-performance threads is considerably more difficult with composite materials than with metals. Furthermore, the stiffness of non-metallic composite materials is usually lower than that of metals.
[0011] In contrast to the commonly used fixation methods by screwing in a clamping element, other methods for securing the screws to a connecting rod via a tulip head are also known in the prior art for pedicle systems. For example, US Pat. No. 6,251,112 B1 discloses a pedicle system in which the screws are attached to the connecting rod by means of a clamp that can be screwed onto the tulip head. A fixing screw can be screwed into the clamp to clamp the tulip head, which is formed integrally with the screw, to the connecting rod. Thus, securing a screw to the connecting rod requires a relatively large number of steps for the physician.
[0012] In the system shown in document US 2010 / 0114168 A1, a slotted plate is placed on the tulip head to secure a pedicle screw to the connecting rod. Clamping is achieved by means of an insert inserted into a central opening in the plate. The disadvantage of this solution is that it only fits connecting rods with a specific diameter.
[0013] Document WO 2006 / 119271 A2 discloses a fixation system for a pedicle system in which a fastening element is attached to the tulip head via a bayonet connection to fix the connecting rod to a screw. Here, too, the system is only designed for connecting rods with a specific diameter.
[0014] The document US 2004 / 0138660 A 1 discloses a fixation system for a pedicle system with a fixation cap that is screwed onto a tulip head and presses the connecting rod against the screw head with a pressure element attached to the underside.
[0015] Document US 6,478,797 B1 shows the fixation of a connecting rod to a screw by means of a retaining element that engages over a tulip head formed integrally with the screw and presses the connecting rod downward via a central saddle element. The connection between the retaining element and the tulip head is established via a threaded or bayonet-like mechanism.
[0016] Document WO 2005 / 122927 A1 discloses a pedicle system in which a retaining element is locked to the tulip head via locking teeth for fixing a pedicle screw to a connecting rod. The retaining element and tulip head are each made of metal or plastic. While metal has the aforementioned disadvantages, particularly regarding radiopacity, pure plastic generally exhibits relatively low strength and rigidity and is therefore not very suitable for medical bone connections in practice.
[0017] PRESENTATION OF THE INVENTION
[0018] It is an object of the present invention to provide a largely radiotransparent device which allows a simple and at the same time high-performance connection of bones or bone parts.
[0019] To achieve this object, a medical bone joining device is proposed as defined in claim 1. Claim 16 specifies a method for joining two bones or bone parts, which is preferably carried out using such a bone joining device. Advantageous embodiments of the invention are defined in the dependent claims.
[0020] The present invention therefore provides a medical bone connection device for connecting two bones or bone parts of a human or animal patient, comprising a first connecting element made of a fiber-reinforced plastic material, which has a first locking structure with a plurality of first locking elements, in particular locking teeth; and a second connecting element made of a fiber-reinforced plastic material, which has a second locking structure with a plurality of second locking elements, in particular locking teeth.
[0021] According to the invention, the first locking elements of the first locking structure can be locked with the second locking elements of the second locking structure in order to fix the first connecting element and the second connecting element to one another and thereby connect the two bones or bone parts to one another.
[0022] Fixing the two connecting elements to each other by means of locking has proven particularly advantageous in combination with manufacturing the connecting elements from a fiber-reinforced plastic material. On the one hand, the fiber-reinforced plastic material enables the production of connecting elements that are not only X-ray transparent, but also exhibit high strength and rigidity, thus enabling a particularly high-performance connection of the bones or bone parts. The use of fibers, preferably carbon fibers, in the plastic material not only enables the reinforcement of the respective component as a whole, but also allows the component to be specifically reinforced at specific locations. Such a specifically reinforced location can, in the first and / or second connecting element, be the locking structure in particular. By appropriately aligning the fibers, the reinforcement can even be direction-dependent.It has been shown that a snap-in connection allows considerably larger tolerances and a significantly higher surface roughness in the connecting areas of the respective components compared to a threaded connection. Consequently, the provision of a snap-in connection is particularly well suited for connecting elements made from a fiber-reinforced plastic material. In contrast to a bayonet connection, for example, the snap-in connection has the further advantage that the two connecting elements can engage with each other to a greater or lesser extent as required. For example, the snap-in structures can be continuously brought into further engagement with each other, similar to a threaded connection, in order to reinforce the fixation of the connecting elements to one another or to increase the clamping force on a component arranged between the two connecting elements.
[0023] The locking mechanism of the locking elements also makes it particularly easy for the user, i.e., typically the physician, to secure the two connecting elements together. A twisting movement, which can place additional strain on the weakened spine, is unnecessary; the two connecting elements can generally simply be slotted together, meaning that the joining, pressing, and securing of the connecting elements takes place in a single step, i.e., with a single, continuous movement. This also makes connecting the bones or bone parts by the physician much faster.
[0024] The locking elements of the first locking structure can, in particular, be locking teeth. Likewise, the locking elements of the second locking structure can, in particular, also be locking teeth. However, embodiments are also possible in which only the locking elements of one of the two locking structures are designed as locking teeth, while the locking elements of the other locking structure are designed, for example, as recesses or openings, thereby forming an engagement structure for the locking teeth. A locking tooth is generally a protruding, in particular serrated or toothed element.
[0025] The bone connection device typically has at least a first component, which is designed to be connected to a first bone or bone part, and a second component, which is designed to be connected to a second bone or bone part. To produce the bone connection, the two components are connected to one another by means of the first and the second connecting element. The two components mentioned can be the first and the second connecting element themselves. Preferably, however, the two components to be directly connected to a bone or bone part each represent separate elements with respect to the two connecting elements. Advantageously, however, the components to be directly connected to the bone or bone part can be attached, in particular fixed, to the first or second connecting part.
[0026] A connection to a bone or bone part means that a corresponding component is attached to the bone or bone part in such a way that it cannot change its position relative to it, even if the patient moves. For this purpose, the component can be anchored in the bone or bone part, in particular screwed in. Alternatively, it can also only rest on the outside of the bone, in which case it is ensured, for example via other components and / or the surrounding tissue, that the component cannot move relative to the bone. Gluing the component to the bone or bone part, for example using bone cement, is also conceivable.
[0027] Thermoplastics are preferably used as the plastic material, particularly preferably so-called high-temperature thermoplastics from the polyaryletherketone, polyimide, and polysulfone families. Carbon fibers are preferably used as the fibers. The fiber-reinforced plastic material of the first and / or second connecting element is particularly preferably carbon fiber-reinforced polyetheretherketone (PEEK). The first and second connecting elements are preferably made of the same materials.
[0028] The fiber length is preferably at least 1 mm. To achieve particularly good strength of the first and / or second connecting element, the fibers advantageously have a length that corresponds at least to the entire length of the respective connecting element along its main direction of extension. The fiber volume content is preferably in a range of 20 to 80%, more preferably in a range of 35 to 70%, particularly preferably in a range of 45 to 60%.
[0029] The basic manufacturing process for the connecting elements can be carried out using a process conventionally known in the composites sector. These include, among others, pressing processes, winding processes, tape-laying processes, pultrusion processes, and long-fiber injection molding processes, such as "Composite Flow Molding" (CMF). For the production of the connecting elements and, if present, other components of the bone connection device, the pressing process described in document DE 44 45 305 C1 is preferred. The connecting elements can also be manufactured using so-called additive manufacturing processes, such as 3D printing (short-, long-, or continuously fiber-reinforced), or a combination of the above-mentioned processes. Unidirectional prepregs, rods, and fabric prepregs are preferred as starting materials for these processes. Both are geometrically flat or round-shaped starting materials.As a rule, in the above-mentioned processes, the prepregs are preformed into preforms and welded under pressure and temperature, for example in a press tool, and then cooled.
[0030] The above-mentioned processes for producing the connecting elements and, if applicable, the other components are preferably near-net-shape manufacturing processes, which means that such manufactured connecting elements and / or components generally require only minor mechanical post-processing in terms of shape and dimensions.
[0031] The locking elements, in particular locking teeth, of a respective locking structure are preferably arranged parallel to one another and advantageously have an identical cross-sectional shape. However, the locking elements of a respective locking structure can be arranged in groups, whereby the locking elements of different groups can, for example, have different orientations. For example, the locking elements of a first group can face in a first direction, and the locking elements of a second group can face in an opposite direction, so that the two groups face each other.
[0032] In order to achieve particularly secure fixation, a respective locking structure preferably has two or four locking elements or, more preferably, one or two pairs of locking elements. A pair of locking elements is each formed by two individual locking elements, which are preferably arranged at the same height as the corresponding locking structure and are advantageously facing or facing away from one another, i.e. are arranged opposite one another. The first locking structure preferably has one or two such pairs of locking elements and the second locking structure likewise has one or two pairs of locking elements. It has been found that good locking of the two locking structures is possible and particularly secure fixation is achieved if both the first locking structure and the second locking structure have two pairs of locking elements.The two pairs are then preferably arranged one above the other, i.e., at different levels with respect to the locking direction. With two pairs of locking elements, two locking elements are preferably arranged parallel to each other on each side.
[0033] In other embodiments, which are also preferred depending on the application, a respective locking structure has at least three, more preferably at least five, and most preferably at least ten locking elements arranged parallel to one another, wherein these locking elements can each form part of three, at least five, or at least ten pairs of locking elements arranged at the same height. In this way, locking of the two connecting elements in several different positions is possible.
[0034] To enable the first and second connecting elements to lock together via the locking structures, the first and / or second connecting element has a certain degree of elasticity in the region of the locking structure. This elasticity can be achieved, in particular, by the material and / or geometric design of the connecting element.
[0035] Preferably, the locking structure of the first connecting element is designed to be complementary to the locking structure of the second connecting element, so that a positive connection can be created between the two connecting elements when they are mutually locked.
[0036] According to a preferred embodiment, the first locking elements and the second locking elements are each designed with an undercut such that a release of the fixation between the first connecting element and the second connecting element is prevented when the first locking structure and the second locking structure are locked together. In this case, the locked locking elements engage with each other in such a way that a release of the connection by simply pulling the two connecting elements apart is impossible. An unintentional release of the connection between the two connecting elements can thus be effectively prevented, even under the application of great force. Preferably, a release of the two connecting elements after locking is only possible with the aid of a tool, in particular a special tool. The bone connection is therefore particularly secure.
[0037] To enable the physician to easily fix the two connecting elements together, the first locking elements and / or the second locking elements each have an inclined surface inclined toward a locking direction, which facilitates locking of the first locking structure with the second locking structure. Preferably, the locking structures can thus be easily engaged with one another, but are difficult to disengage from one another due to the aforementioned undercut.
[0038] The first locking structure is preferably an inner locking structure whose first locking elements face outward in at least two opposite directions, and the second locking structure is preferably an outer locking structure whose second locking elements face inward in at least two opposite directions. In the locked state, the first locking structure is thus preferably arranged within the second locking structure. Because the locking elements of a respective locking structure each face in at least two opposite directions, the locking of the locking structures can accordingly occur from at least two directions. This enables a particularly secure and high-performance fixation of the connecting elements to one another.
[0039] In a particularly preferred embodiment, the bone connection device has a third connecting element, which can in particular be a connecting rod. The connecting rod can, but does not have to, form part of a pedicle system. The first and the second connecting element preferably serve to clamp the third connecting element between them. The second connecting element can in particular be a locking clamp, which is preferably designed to be placed on the first connecting element and to lock with it. The locking clamp is preferably designed as a whole in a C-shape, with two holding webs that are advantageously arranged more or less parallel to one another and a connecting web connecting the holding webs.The second locking elements are then preferably arranged on the holding webs, wherein a first group of locking elements is advantageously arranged on the first holding web and a second group of locking elements is arranged on the second holding web, so that the two groups of locking elements face inwards towards each other.
[0040] Preferably, the locking connection is arranged at the same height as the third connecting element in the locked state of the first and second connecting elements along the locking direction. An arrangement at the same height means that the mutual locking engagement of the first and second locking structures along the locking direction occurs at the same height, i.e., partially or completely overlapping, with the third connecting element. In this way, the space requirement of the bone connection device along the locking direction can be minimized. This reduction in the overall height of the device along the locking direction is particularly advantageous in pediatric applications, as well as in high-thoracic and cervical applications.
[0041] The locking clip preferably has a clamping element which serves to clamp the third connecting element, wherein the clamping element is advantageously designed to lie directly against the third connecting element. In the locked state, the third connecting element is preferably arranged between the clamping element of the locking clip and the first connecting element and is thereby clamped. In principle, it is conceivable for the clamping element to be arranged outside the second locking elements on the locking clip. However, in order to achieve particularly effective clamping, it is preferred if the clamping element is arranged within the second locking elements and advantageously centrally on the locking clip. The force can then be transmitted via the clamping element in a particularly efficient manner. The clamping element is preferably attached to the connecting web and projects relative to it in the direction of the third connecting element.
[0042] To further increase the clamping effect, the clamping surface of the clamping element and / or the third connecting element can have a friction-increasing coating.
[0043] To adjust the flexibility of the locking clip, it can have one or more local indentations in an area between the inward-facing second locking elements. Due to the one or more local indentations, the locking clip preferably has a material taper in each corresponding area, which increases the flexibility of the locking clip. Depending on the severity of these indentations, locking with the first connecting element is made easier or more difficult for the physician, and simultaneously, releasing the locking connection is made easier or more difficult. Preferably, one to three such indentations are provided.
[0044] To allow the first and second locking structures to be completely released from one another if necessary, or to reduce the mutual engagement of the locking structures, the first connecting element and / or the second connecting element advantageously has an intervention structure that enables the locking connection to be released, for example, with the aid of a suitable tool. The intervention structure can be arranged, in particular, on the outside of the first or second locking structure.
[0045] In a particularly preferred embodiment, the third connecting element is a connecting rod and the first connecting element is a tulip head, which serves to fix the connecting rod to a threaded shaft of a screw, in particular a pedicle screw. The bone connecting device then therefore represents a pedicle system. Depending on the embodiment, the tulip head can be formed integrally with the screw or represent a separate component in which the screw head of the screw is held. It is preferably a polyaxial fixation system in which the position of the threaded shaft of the screw or screws is adjustable relative to the connecting rod. The second connecting element, which is advantageously designed as a locking clamp, then preferably serves to clamp the connecting rod to the tulip head. The first locking structure is then preferably formed on the outside of the tulip head.If the pedicle system is designed as a polyaxial fixation system, the second connecting element and / or a clamping element formed, for example, on the locking clamp can serve to clamp the screw to the tulip head by the connecting rod or the clamping element pressing the screw head against a stop surface provided on the tulip head. Depending on the situation, a so-called washer can also be provided between the connecting rod and the tulip head or between the clamping element and the tulip head. The washer can be used to improve, in particular, the force transmission from the connecting rod or clamping element to the screw head. Compared to the conventional clamping of the connecting rod to the tulip head using a clamping element with an external thread, clamping with a locking clamp has the advantage that the space required on the side of the connecting rod opposite the screw is considerably reduced.In addition, no rotational movement is necessary for fixation.
[0046] In another, likewise preferred embodiment, the third connecting element is a connecting rod and the first connecting element is a connector, in particular an axial connector or a parallel connector, which serves to connect two connecting rods. Here, too, the second connecting element is advantageously designed as a locking clip, and the first locking structure is preferably arranged on the outside of the connector. However, the first locking structure can also be formed on the connecting rod, in particular on an end region of the connecting rod. In the case of an axial connector, two preferably identically designed locking clips can be provided, one serving to clamp the first connecting rod and the other to clamp the second connecting rod.In the case of a parallel connector, a single locking clamp can be provided with two clamping elements, with the first clamping element serving to clamp the first connecting rod and the second clamping element serving to clamp the second connecting rod. The connector then forms a connector system together with the second connecting element(s) and, if applicable, the connecting rods.
[0047] Preferably, the connector has at least one opening for receiving a connecting rod, which widens along the locking direction toward the second connecting element. In this way, the connector can be used to connect connecting rods of different diameters.
[0048] In yet another and likewise preferred embodiment, the first connecting element is a screw and the second connecting element is a bone plate. Preferably, a plurality of first connecting elements in the form of screws are present. The screw or screws and bone plate can in particular together form a cervical plate system which serves to stabilize the cervical spine. The screw or screws preferably each have an at least partially elastically deformable screw head on which the first locking structure is formed. The second locking structure is preferably provided on the boundary surface of openings which are formed in the bone plate. The screw or screws can then be fixed in the openings of the bone plate with their first locking structure provided on the screw head.Preferably, the first locking elements of the screw(s) and / or the second locking elements of the bone plate form a thread. The at least partially elastic design of the screw head with the first locking structure formed thereon makes it possible to fix the respective screw at different angular positions on the bone plate. If a thread is present, the screw can be screwed with its screw head in the desired angular position into the corresponding opening in the bone plate. If the screw is screwed in at an angle, mutual engagement of the locking structures is impossible in certain areas. The elasticity of the screw head nevertheless makes screwing in possible in this case, since the locking structures cannot then engage with one another in the aforementioned areas, but can engage with one another in others.the screws are preferably designed for direct screwing into a bone, in particular into a vertebral body of the cervical spine.
[0049] In a further, likewise preferred embodiment, the bone connection device is designed as a vertebral body replacement. The first connecting element can then be, in particular, an expansion slide, and the second connecting element an expansion body. The expansion slide and expansion body can then be locked together with their respective locking structures at different positions along the longitudinal extent of the vertebral body replacement in order to adapt the longitudinal extent of the vertebral body to the patient. To better adapt the vertebral body replacement to the anatomical conditions of the patient, the first and second locking structures can each be curved. The locking of the expansion slide and expansion body then takes place along a correspondingly curved locking direction.
[0050] To guide the first locking structure relative to the second locking structure during fastening, the first connecting element and the second connecting element preferably have interlocking guides, which together can, in particular, form a dovetail joint. This ensures correct fastening of the two connecting elements to one another.
[0051] According to a further development of the invention, the second connecting element has a locking clip, which forms the second locking structure and is connected to the remaining second connecting element via a flexible element. Preferably, the locking clip is connected to the remaining second connecting element exclusively via the flexible element. The flexible element is preferably a web, which can in particular be formed integrally with the locking clip and / or the remaining second connecting element. The flexibility preferably refers to the remaining second connecting element, which generally has less flexibility than the flexible element.If, for example, the third connecting element is formed by a connecting rod and the second connecting element serves to attach the connecting rod to a pedicle screw, the provision of the flexible element can have the advantage of allowing a certain degree of freedom of movement between the connecting rod and the pedicle screw despite the attachment. This can, in particular, reduce a stress discontinuity between the levels of the spine provided with the pedicle system and the adjacent sections of the spine. By creating a more gradual transition between the section of the spine stiffened by the pedicle system and the still mobile sections, the likelihood of proximal junctional kyphosis can be reduced and, at the same time, the adjacent intervertebral discs and vertebral bodies can be protected from further degeneration and unphysiological loading patterns.
[0052] According to another embodiment of the invention, the first connecting element and the second connecting element, when locked together, are displaceable relative to one another along the longitudinal direction of the first and second locking elements. The second connecting element can, in particular, have a locking clip. Preferably, the second connecting element is also a connecting rod. The first connecting element can also be a connecting rod. Thus, in this embodiment of the invention, the first and second connecting elements are displaceable relative to one another over at least a specific range, despite being secured to one another by means of the locking structures.Preferably, however, the movement is only possible over a limited range, meaning that there is a stop on both sides to limit the range of motion and prevent the two connecting elements from becoming detached during movement. Depending on the application and patient situation, such limited mobility can have advantages with regard to the treatment outcome.
[0053] The bone connection device according to the invention can be, for example, a pedicle system, a connector system, such as an axial or parallel connector system, a cervical plate system, a vertebral body replacement, or an intervertebral disc cage. Similar to the vertebral body replacement, the intervertebral disc cage can also be expandable.
[0054] The invention also relates to a method for connecting two bones or bone parts of a human or animal patient, in particular by means of a bone connecting device as specified above, wherein a first connecting element made of a fiber-reinforced plastic material and a second connecting element made of a fiber-reinforced plastic material are fixed to one another by locking a plurality of first locking elements of a first locking structure of the first connecting element with a plurality of second locking elements of a second locking structure of the second connecting element. The fixing of the two connecting elements to one another preferably takes place by means of a purely translational movement of the two connecting elements relative to one another, i.e., preferably, no rotational movement is performed.
[0055] BRIEF DESCRIPTION OF THE DRAWINGS
[0056] Preferred embodiments of the invention are described below with reference to the drawings, which are for illustrative purposes only and are not to be construed as limiting. In the drawings:
[0057] Fig. 1a is a perspective view of a pedicle screw of a pedicle system according to the invention fixed to a connecting rod by means of a tulip head and a locking clamp;
[0058] Fig. 1b is an exploded perspective view of the device of Fig. 1a;
[0059] Fig. 1c is a side view of the device of Fig. 1a from a first viewing direction;
[0060] Fig. 1d is a side view of the device of Fig. 1a from a second viewing direction;
[0061] Fig. 1e is a first central cross-sectional view of the device of Fig. 1a;
[0062] Fig. 1f is a second central cross-sectional view of the device of Fig. 1a;
[0063] Fig. 1g is an enlarged detailed view of the area outlined in dashed lines in Fig. 1d;
[0064] Fig. 2 is a perspective view of the locking clamp of another pedicle system according to the invention;
[0065] Fig. 3 is a perspective view of the locking clamp of yet another pedicle system according to the invention;
[0066] Fig. 4a is a perspective view of a pedicle screw of another pedicle system according to the invention, fixed to a connecting rod by means of a tulip head and a locking clamp;
[0067] Fig. 4b is an exploded perspective view of the device of Fig. 4a;
[0068] Fig. 5 is a perspective view of the locking clamp of another pedicle system according to the invention;
[0069] Fig. 6a is a perspective view of a tulip head and a
[0070] Locking clamp on a connecting rod fixed pedicle screw of yet another pedicle system according to the invention;
[0071] Fig. 6b is an exploded perspective view of the device of Fig. 6a;
[0072] Fig. 7 is a perspective view of the locking clamp of another pedicle system according to the invention;
[0073] Fig. 8a is a perspective view of a tulip head and a
[0074] Locking clamp on a connecting rod fixed pedicle screw of yet another pedicle system according to the invention;
[0075] Fig. 8b is an exploded perspective view of the device of Fig. 8a;
[0076] Fig. 9a is a perspective view of two connecting rods connected to one another by means of an axial connector of an axial connector system according to the invention;
[0077] Fig. 9b is an exploded perspective view of the device of Fig. 9a;
[0078] Fig. 9c is a first central cross-sectional view of the device of Fig. 9a;
[0079] Fig. 9d shows a second cross-sectional view along the plane IX-IX shown in Fig. 9c of the device of Fig. 9a; Fig. 10a shows a perspective view of two connecting rods connected to one another by means of an axial connector of an axial connector system according to the invention according to another embodiment;
[0080] Fig. 10b is a side view of the device of Fig. 10a;
[0081] Fig. 10c is an exploded perspective view of the device of Fig. 10a;
[0082] Fig. 11a is a perspective view of two connecting rods connected to one another by means of a parallel connector of a parallel connector system according to the invention;
[0083] Fig. 11b is an exploded perspective view of the device of Fig. 11a;
[0084] Fig. 11c is a side view of the device of Fig. 11a;
[0085] Fig. 12a is a perspective view of a cervical plate system according to the invention with several screws fixed in a bone plate;
[0086] Fig. 12b is an exploded perspective view of the device of Fig. 12a;
[0087] Fig. 12c is a cross-sectional view of the device of Fig. 12a in a plane centrally located by three screws;
[0088] Fig. 13a is a perspective view of a vertebral body replacement according to the invention;
[0089] Fig. 13b is an exploded perspective view of the device of Fig. 13a; Fig. 13c is a central cross-sectional view of the device of Fig. 13a, in an unexpanded state;
[0090] Fig. 13d is a central cross-sectional view of the device of Fig. 13a, in an expanded state;
[0091] Fig. 14a is a perspective view of another vertebral body replacement according to the invention with curved locking structures;
[0092] Fig. 14b is an exploded perspective view of the device of Fig. 14a;
[0093] Fig. 14c is a central cross-sectional view of the device of Fig. 14a, in an unexpanded state;
[0094] Fig. 14d is a central cross-sectional view of the device of Fig. 14a, in an expanded state;
[0095] Fig. 15a is a perspective exploded view of a pedicle screw of a pedicle system according to the invention, fixed to a connecting rod by means of a tulip head and a locking clamp, according to a further embodiment;
[0096] Fig. 15b is a central cross-sectional view of the device of Fig. 15a;
[0097] Fig. 16a is a perspective view of a pedicle screw of a pedicle system according to the invention, fixed to a connecting rod by means of a tulip head and a locking clamp, according to yet another embodiment; Fig. 16b is a perspective view of the device of Fig. 16a;
[0098] Fig. 17a is a side view of a bone connecting device in the form of two ends of two connecting rods slidably connected to one another via a locking connection;
[0099] Fig. 17b is a perspective view of the device of Fig. 17a;
[0100] Fig. 18a is a central cross-sectional view of a fenestrated pedicle screw of a pedicle system according to the invention, fixed to a connecting rod by means of a tulip head and a locking clamp, according to a further embodiment;
[0101] Fig. 18b is an exploded perspective view of the device of Fig. 18a;
[0102] Fig. 19a shows a central cross-sectional view of a fenestrated pedicle screw of a pedicle system according to the invention, fixed to a connecting rod by means of a tulip head and a locking clamp, according to yet another embodiment; and
[0103] Fig. 19b is an exploded perspective view of the device of Fig. 19a.
[0104] DESCRIPTION OF PREFERRED EMBODIMENTS
[0105] Figures 1a to 19b show various embodiments of medical bone-connecting devices according to the invention, as well as parts thereof. Elements of different or identical embodiments that function identically or similarly are each provided with the same reference numerals.
[0106] Figures 1a to 1g show, in different views, a first preferred embodiment of a bone connection device according to the invention in the form of a polyaxial fixation system 1. The polyaxial fixation system 1 is designed as a pedicle system comprising a plurality of screws 12, which can also be referred to as pedicle screws and can each be screwed into a vertebral body of the spine of a human or animal patient. Each of the screws 12 is attached to a connecting rod 11 by means of a tulip head 13. The connecting rod 11 thus connects the screws 12 to one another and thereby blocks or stabilizes the corresponding vertebral bodies. The connecting rod 11 is preferably made as a single piece from a fiber-reinforced plastic material.
[0107] The screw 12 has a largely spherical screw head 121 in which an engagement structure 122 is formed. The engagement structure 122 is, for example, hexagonal or Torx-shaped and serves to screw the screw 12 into a vertebral body with the aid of a corresponding tool. The screw 12 has a threaded shaft 123 that extends from the screw head 12 to a screw tip 124.
[0108] The screw 12 is preferably made as a single piece from a fiber-reinforced plastic material. In this way, the X-ray transparency of the polyaxial fixation system 1 can be ensured. In order to still clearly recognize the position and orientation of the polyaxial fixation system 1 and in particular of the screws 12 during X-ray imaging or other medical imaging, such as magnetic resonance imaging,
[0109] 12 Markers, particularly radiopaque markers, may be provided. Such a marker can, for example, be inserted into a recess provided at the screw tip 124 (visible in Figures 1e and 1f).
[0110] The tulip head 13, which is also made of a fiber-reinforced plastic material and preferably made as a single piece, has a base body 131 from which two diametrically opposed lateral webs 132 and 132' extend upward. The two lateral webs 132, 132' laterally delimit two receiving openings 135, 135' arranged therebetween and open at the top, which serve to receive the connecting rod 11. On the radial outer side of the lateral webs 132 and 132', a locking structure 133 is formed, which is formed by locking elements in the form of locking teeth 134 and 134'. A first group of identically designed locking teeth 134, arranged parallel to one another, is provided on the first lateral web 134, and a second group is provided on the second lateral web 134.
[0111] Below the receiving openings 135, 135', the base body 131 of the tulip head
[0112] 13 has an interior space 136 that serves to accommodate the screw head 121 of the screw 12. For this purpose, the screw 12 is inserted from above into the tulip head 13 with the threaded shaft 123 first until the screw head 121 abuts against a contact surface 137 that defines the interior space 136 (see Figures 1e and 1f). Due to the spherical shape of the screw head 121, the screw 12 can be arranged and fixed at different angular positions relative to the tulip head 13. The tulip head 13 thus forms a connecting element for connecting and fixing the screw 12 to the connecting rod 11. A locking clamp 15 is used to fix the screw 12 and the connecting rod 11 in a desired position on the tulip head 13.The locking clip 15, which is made of a fiber-reinforced plastic material and is preferably made in one piece, has a C-shaped configuration as a whole with two parallel, freely projecting retaining webs 152, 152' and a connecting web 151 connecting the retaining webs 152, 152'. On the radial inner sides of the retaining webs 152, 152', a locking structure 153 is formed, each having a plurality of locking elements in the form of locking teeth 154 and 154', respectively. A first group of identically designed locking teeth 154, arranged parallel to one another, is provided on the first retaining web 152, and a second group is provided on the second retaining web 152'. The locking teeth 154, 154' thus face radially inward.Between the holding webs 152 and 152', a clamping element 155 is attached centrally to the connecting web 151, which projects downwards from the latter parallel to the holding webs 152, 152' and forms a saddle-shaped contact surface, possibly coated (higher friction, locking), adapted to the outer surface of the connecting rod 11.
[0113] To connect the screw 12 to the connecting rod 11, the connecting rod 11 is inserted into the receiving openings 135, 135' of the tulip head 13, with the screw head 121 already received in the interior 136 of the tulip head 13. Subsequently, for fixation, the locking clip 15 is placed with its retaining webs 152, 152' first onto the lateral webs 132, 132' of the tulip head 13, so that the locking structure 153 of the locking clip 15 engages with the locking structure 133 of the tulip head 13. By pressing the locking clip 15 onto the tulip head 13 along a locking direction R, the mutual engagement of the locking structures 153 and 133 can be increased, and the clamping force acting on the connecting rod 11 can thereby be increased. The clamping element 155 presses the connecting rod 11 onto the screw head 121 arranged underneath, which in turn is pressed against the contact surface 137 of the tulip head 13 and is thereby clamped.In order to increase the clamping effect, the clamping surface of the clamping element 155 and / or the connecting rod 11 can have a friction-increasing coating.
[0114] As can be seen in the enlarged detailed view of Figure 1g, the inner locking teeth 134, 134' of the tulip head 13 each have a first surface facing away from the locking clip 15, which is perpendicular to the locking direction R, and a second surface facing towards the locking clip 15, which is inclined to the locking direction R. Analogously, the locking teeth 154, 154' of the locking clip 15, which are designed to be complementary, each have a first surface facing towards the tulip head 13, which is perpendicular to the locking direction R, and a second surface facing away from the tulip head 13, which is inclined to the locking direction R. The first and second surfaces of the locking teeth 134, 134' and 154, 154' are thus each at an acute angle to one another.The first surfaces of the locking teeth 134, 134' and 154, 154', which are perpendicular to the locking direction R, thus jointly form an undercut which, after mutual locking, prevents the locking clip 15 from being removed from the tulip head 13. The second surfaces of the locking teeth 134, 134' and 154, 154', however, allow the locking clip 15 to be easily attached and snapped onto the tulip head 13 due to their inclination to the locking direction R.
[0115] To achieve better pressing of the screw head 121 against the contact surface 137 of the tulip head 13, a so-called washer 14 is preferably arranged between the connecting rod 11 and the screw head 121. The washer 14 is annular, as can be seen in Figure 1b. It can be made of a metal or a plastic material, in particular a fiber-reinforced plastic material. To prevent movement between the washer 14 and the screw 12 even more effectively, one or both of the abutting surfaces of the washer 14 and the screw head 121 can have a friction-increasing coating and / or a surface structure. The surface structure can be formed, for example, by grooves or notches.
[0116] To facilitate the application and locking of the locking clip 15, which serves as a connecting element, onto the tulip head 13, the locking clip 15 and / or the tulip head 13 advantageously have a certain degree of elasticity. Such elasticity can be achieved, for example, by providing a slot 156 or 156' running in the longitudinal or axial direction on the retaining webs 152, 152' of the locking clip 15, as is the case in the embodiment of Figures 1a to 1g. Alternatively or additionally, a local recess 157 can be provided on the upper side of the connecting web 151 of the locking clip 15, as shown in the locking clip 15 of the embodiment of Figure 2. The recess 157 is arranged centrally between the two retaining webs 152, 152' and extends parallel to the retaining webs 152, 152' in the longitudinal direction of the connecting rod 11.By adjusting the dimensions of the recess 157, the elasticity of the locking clip 15 can be set very precisely. Due to the recess 157, the locking clip 15 thus forms a spring element. In another embodiment, shown in Figure 3, the spring effect of the locking clip 15 is achieved by two recesses 157 arranged laterally on the connecting web 151. Here, too, the recesses 157 each run parallel to the holding webs 152, 152' in the longitudinal direction of the connecting rod 11. Depending on the embodiment, the central recess 157 of Figure 2 can also be combined with the two lateral recesses 157 of Figure 3.
[0117] In the embodiment of Figure 3, no slot 156 or 156' is provided on the retaining webs 152, 152'. Instead, an outwardly projecting, bow-shaped intervention structure 159 is attached to the radial outer side of the retaining webs 152, 152' in the region of their free ends. The intervention structures 159 serve to release the mutual engagement of the locking structures 133 and 153 when necessary in order to release the fastening of the connecting rod 11 to the tulip head 13. For this purpose, the intervention structures 159 can be gripped behind with a suitable tool in order to move the retaining webs 152, 152' outward in the radial direction.
[0118] In the embodiment of Figures 4a and 4b, the locking clip 15 has neither a slot 156, 156' nor a local recess 157. The elasticity in the region of the locking structure 153 can be achieved, for example, by an appropriate choice of material during the manufacture of the locking clip 15.
[0119] Figure 5 shows an embodiment of a locking clip 15, which has a slot 156 extending in the axial direction on the retaining webs 152, 152', similar to the locking clip 15 in Figure 1b. Two bow-shaped intervention structures 159 are attached to the retaining web 152 and 152', respectively, laterally to the slot 156. Two parallel recesses 157 are formed on the connecting web 151 to impart a certain flexibility to the locking clip 15 with regard to locking.
[0120] While the lateral webs 132, 132' of the tulip head 13 in the embodiments of Figures 1a to 4b each have rounded outer surfaces with locking teeth 134, 134' that are correspondingly rounded in their longitudinal extension, the outer surfaces of the lateral webs 132, 132' in the embodiment of Figures 6a and 6b are each flat. Accordingly, the locking teeth 134, 134' also extend in a straight line along their longitudinal extension. The same applies analogously to the inner surfaces of the retaining webs 152, 152' and the locking teeth 154, 154' formed thereon.
[0121] Figure 7 shows a further embodiment of a locking clip 15, which, similar to that of Figures 3 and 5, has two parallel recesses 157 on the upper side of the connecting web 151 to effect the locking clip elasticity. The locking clip 15 is otherwise designed largely like that of Figures 6a and 6b, but additionally has an intervention structure 159 on the outer sides of the holding webs 152 in order to be able to release the locking clip 15 from the tulip head 13 using a suitable tool if necessary. The provision of intervention structures 159, which serve to release the mutual engagement of the locking structures, but can also be designed differently than in the present and previously described embodiments, is of course also conceivable for each of the locking clips 15 of the embodiments of Figures 1a to 2 as well as 4a, 4b and 6a, 6b.The locking clips 15, 24 and 34 of the embodiments of Figures 8a to 11c described below can also have such intervention structures 159 for releasing the mutual engagement of the locking structures.
[0122] The embodiment of Figures 8a and 8b differs from that of Figures 6a and 6b in that guides are provided on the locking clip 15 and on the tulip head 13 to laterally guide the locking clip 15 onto the tulip head 13 and thereby ensure correct attachment of the locking clip 15. For lateral guidance, a dovetail inner guide 158, 158' in the form of a downwardly projecting projection is provided on each of the holding webs 152. On the outside of the tulip head 13, two complementary dovetail outer guides 138, 138' are provided, each in the form of a short guide groove extending parallel to the locking direction R. Furthermore, in the embodiment of Figures 8a and 8b, in contrast to that of Figures 6a and 6b, a central recess 157 is formed on the upper side of the connecting web 151 of the locking clip 15.
[0123] Figures 9a to 9d, 10a to 10c, and 11a to 11c show further embodiments of bone connection devices according to the invention, which are designed here as connectors for connecting and fixing two connecting rods 21 and 22, or 31 and 32, respectively. The connecting rods 21 and 22, or 31 and 32, are connected to one or more bones or bone parts via further components not shown in the figures, such as screws in particular. While the embodiment of Figures 9a to 9d and 10a to 10c each represents an axial connector system 2, the embodiment of Figures 11a to 11c relates to a parallel connector system 3.
[0124] The axial connector system 2 of Figures 9a to 9d comprises an axial connector 23, which forms a housing designed to receive a first connecting rod 21 and a second connecting rod 22 from opposite sides. For this purpose, the connecting rods 21 and 22 are each inserted into a receiving opening 232 and 232', respectively, formed by a base body 231 of the axial connector 23. The free ends of the connecting rods 21, 22 each protrude into an interior space 235 and 235', respectively (see Figures 9c and 9d), where they can be clamped by means of a respective locking clip 24.
[0125] The two almost identically designed locking clips 24 have a similar design to the locking clip of the embodiment of Figures 6a and 6b. They have an overall C-shape with two parallel holding webs 242, 242' and a connecting web 241 connecting them. Between the holding webs 242, 242', a clamping element 245 with an underside shaped complementarily to the connecting rod 21 or 22 is provided on the underside of the connecting rod 241. While the clamping element 245 of the first locking clip 24, which rests on the first, thicker connecting rod 21, is somewhat wider, that of the second locking clip 24, which rests on the second, thinner connecting rod 22, is correspondingly narrower. In this way, a tight fit of the respective locking clip 24 on both connecting rods 21, 22 is ensured.
[0126] The base body 231 and the locking clips 24 thus each form a connecting element. They are preferably made of a single piece and made of a fiber-reinforced plastic material.
[0127] To clamp the connecting rods 21 and 22 to the axial connector 23, the locking clips 24 are attached to the base body 231. Corresponding locking structures 233 and 233' with a plurality of locking teeth 234 and 234' are provided on the outside of the base body 231. A correspondingly complementary locking structure 243 with locking teeth 244 and 244' is formed on the inside of each of the two locking clips 24. When the locking clips 24 are applied to the axial connector 23, the locking structures 233 and 243, or 233' and 243, engage with each other, thereby fixing the respective locking clip 24 to the base body 231. By pressing the respective locking clamp 24 further against the base body 231, the clamping of the connecting rod 21 or 22 can be reinforced.
[0128] In order to be able to use the same base body 231 for connecting rods 21 and 22 of different thicknesses, the receiving openings 232, 232' are each surrounded by a contact surface 236 and 236', respectively, which widens along the locking direction R towards the locking clamp 24, as can be seen in particular in Figure 9d.
[0129] After the two connecting rods 21, 22 have been connected and secured by means of the axial connector 23, the connecting rods are arranged one behind the other along their longitudinal extent. As can be seen in Figure 9c, the axial connector 23 can cause a certain inclination of the connecting rods 21, 22 relative to one another, i.e., the first connecting rod 21 extends at a certain angle along its longitudinal extent relative to the second connecting rod 22.
[0130] Figures 10a to 10c show another embodiment of an axial connector system 2, which has two locking clips 24, which are connected to one another by means of a connecting section 247 and are thus preferably formed together in one piece. The connecting section 247 can connect the two locking clips 24, as here, at a certain angle, so that a corresponding inclination of the interconnected connecting rods 21, 22 relative to one another is effected (see Fig. 10b). The two identically designed locking clips 24 each have a connecting web 241 with a clamping element 245 attached thereto, as well as two holding webs 242, 242' extending parallel from the connecting web 241 and having locking teeth 244 and 244' attached thereto. The locking teeth 244, 244' each form a locking structure 243 which is designed to engage in a locking structure 212 or 222 provided on the connecting rod 21 or 22.For this purpose, the respective free ends of the connecting rods 21, 22 are each formed by a cuboid-shaped locking block 211 or 221, on which the locking structure 212 or 222 with corresponding locking teeth 213, 213' or 223, 223' is formed. The locking block 211 or 221 is advantageously formed integrally with the remaining connecting rod 21 or 22. In this case, the connecting rods 21 and 22 each form a connecting element of the axial connector system 1. Compared to the embodiment of Figures 9a to 9d, the embodiment of Figures 10a to 10c thus has fewer components, but requires a specific design of the connecting rods 21, 22 in their respective end regions. The parallel connector 33 of the parallel connector system 3 shown in Figures 11 a to 11 c also serves to connect two connecting rods 31 and 33 to each other and to fix them to each other.In contrast to the embodiments of Figures 9a to 10c, the connecting rods 31, 33 are arranged and fixed here with their free ends parallel to one another in the base body 331 of the connector. Instead of two locking clips 24, the clamping is achieved here with a single common locking clip 34. The locking clip 34, however, has two clamping elements 345, 345', which are each designed to clamp one of the connecting rods 31, 33 and are adapted in terms of their shape to the diameter of the respective connecting rod 31, 33. The receiving openings 332, 332' for inserting the connecting rods 31 and 33 are also each delimited here by a contact surface 336 or 336' which widens along the locking direction R towards the locking clip 34, thereby enabling the fixing of connecting rods 31, 33 with different diameters.To lock the locking clip 34 to the base body 331, the locking clip 34 has a locking structure 343 with oppositely arranged locking teeth 344 and 344' on its holding webs 342 and 342', which are connected to one another via the connecting web 341. As a complementary counterpart to the locking structure 343, a further locking structure 333 with outwardly projecting locking teeth 334 and 334' is formed on the outside of the base body 331. When the locking clip 34 is locked onto the base body 331, the free ends of the connecting rods 31 and 32 projecting into the interior spaces 335 and 335', respectively, are thus clamped.
[0131] Another embodiment of a bone connection device, which is also according to the invention, is shown in Figures 12a to 12c. This is a cervical plate system 4 with a bone plate 41, which has a base body 411 with a plurality of openings 412, into which a screw 42 can be inserted to connect bones or bone parts. The screws 42 each have a screw head 421 and a threaded shaft 426 extending from this along a longitudinal central axis 428 to a screw tip 427. The screws 42 are designed for anchoring in a bone or bone part, in particular in a vertebral body of the cervical spine. For screwing in the screws 42, a hexagonal or Torx-shaped engagement structure 425 is provided, for example, which is accessible with an appropriate tool through the respective hemispherical screw head 421.Both the bone plate 41 and each of the screws 42 thus form a connecting element of the bone connection device and are preferably each made as a whole in one piece and from a fiber-reinforced plastic material.
[0132] To fix the screws 42 in the openings 412 of the bone plate 41, the screw heads 421 each have a locking structure 423 on their outer side with a plurality of outwardly projecting locking teeth 424. A correspondingly complementary locking structure 413 with a plurality of inwardly projecting locking teeth 414 is formed on the surfaces of the bone plate 41 surrounding the openings 412. Preferably, the locking teeth 424 of the screws 42 and / or the circumferentially extending locking teeth 414 of the bone plate form a thread.
[0133] The screw head 421 of each screw 42 has a certain degree of elasticity, which is achieved by means of slots 422, due to which the screw head 421 is divided into several elastically inwardly pressed segments. When a screw 42 is screwed into an opening 412 such that its longitudinal center axis 428 extends exactly along the longitudinal center axis 415 defined by the locking structure 413 provided in the opening 412, the locking teeth 424 of all segments of the screw head 421 engage the locking structure 413. This is the case with the screw 42 shown on the far right in Figure 12c. If, however, the screw 42 is screwed obliquely into an opening 412, as shown on the far left in Figure 12c, the longitudinal center axis 428 of the screw 42 deviates from the longitudinal center axis 415 predetermined by the locking structure 413.Due to the angular deviations, the locking teeth 424 of certain segments of the screw head 421 can no longer engage in the locking structure 413 of the bone plate 41, but are pushed radially slightly inward, which is made possible by the elasticity of the screw head 421 caused by the slots 422. While these inwardly pressed segments cannot contribute to the fixation of the screw 42 to the bone plate 41, engagement of the locking teeth 424 of other segments of the screw head 421 in the locking structure 413 of the bone plate is still possible even in the oblique position of the screw 42. As a result, fixation of the screw 42 to the bone plate 41 via the locking structures 413 and 423 can be achieved even in the oblique position of the screw 42 relative to the bone plate 41, as shown on the far left in Figure 12c. The screws 42 can thus be fixed in different polyaxial positions on the bone plate 41.
[0134] Figures 13a to 13d show an embodiment of a bone connection device according to the invention in the form of a vertebral body replacement 5. The vertebral body replacement 5 comprises an expansion slide 51, a cover plate 52, an expansion body 53, and a base plate 54, each of which is made of a fiber-reinforced plastic material and is preferably formed as a single piece.
[0135] The expansion slide 51 has an overall cube-like shape, with a base body 511, which forms the centrally arranged component of the vertebral body replacement 5. A connecting structure 512 is formed on the upper side of the base body 511, which enables the attachment and fastening of the cover plate 52 to the expansion slide 51 via, for example, a bayonet connection. The expansion slide 51 has a locking structure 513, which is formed by a plurality of locking teeth 514 and 514' arranged on two opposite sides of the base body 511. The locking teeth 514 and 514' thus face outward in opposite directions and form an internal locking structure.
[0136] The cover plate 52 is formed by a substantially flat base body 521, on the underside of which a connecting structure 522 is formed, which serves to attach and fasten the cover plate 52 to the connecting structure 512 of the expansion slide 51. The expansion slide 51 and the cover plate 52 could in principle also be formed integrally with one another. On the upper side of the base body 521, an upper bone contact surface 523 is formed, which is designed to bear against a bone, in particular against an upper vertebral body of the patient, and has a corresponding surface structure that promotes a close connection and, in particular, bone ingrowth. On two opposite side walls, the base body 521 has a notch 524, which serves to attach an instrument with which the physician can expand the vertebral body replacement 5.
[0137] The expansion body 53 has a substantially cube-shaped base body 531, which is hollow inside and open at the top, thus allowing the expansion slide 51 to be accommodated. A connecting structure 532 is formed on the underside of the base body 531, which enables the attachment and fastening of the base plate 54 via, for example, a bayonet connection. A locking structure 533 with a plurality of locking teeth 534 and 534' is formed on two opposite inner sides of the base body 531. The locking structure 533, which thus forms an outer locking structure, is designed to be complementary to the locking structure 513 of the expansion slide 51 and thereby enables a mutual locking connection between the expansion slide 51 and the expansion body 53. The expansion slide 51 can protrude from the expansion body 53 to different extents depending on the position at which the locking structures 513 and 533 are locked together.In order to maintain a certain elasticity of the outer locking structure 533 relative to the inner locking structure 513, slots 535 are provided laterally to the locking structure 533.
[0138] The base plate 54 has a base body 541, which has a connecting structure 542 on its upper side for attaching the base plate 54 to the connecting structure 532 of the expansion body 53. In principle, the expansion body 53 and the base plate 54 could also be formed together in one piece. On its underside, the base body 541 has a lower bone contact surface 543, which is designed to bear against a bone, in particular against a lower vertebral body of the patient, and has a corresponding surface structure that promotes a close connection and, in particular, bone ingrowth. On two opposite side walls, the base body 541 has a notch 544, which serves to attach an instrument with which the doctor can expand the vertebral body replacement 5.
[0139] The vertebral body replacement 5 is inserted in a non-expanded state, as shown in Figure 13c, into the free space between two vertebral bodies of a patient and is then expanded by the physician to fill the space between the two vertebral bodies and to fit snugly against the vertebral bodies with the bone contact surfaces 523 and 543. The expanded state is shown in Figure 13d. The physician performs the expansion using a tool or instrument (not shown in the figures) that engages in the notches 524 and 544. Due to the surfaces of the locking teeth 514, 514' and 534, 534' being inclined relative to the locking direction R, in combination with the elasticity provided by the slots 535, the expansion carriage 51 can be easily moved out of the expansion body along the locking direction R.In the opposite direction, however, the locking teeth 514, 514' and 534, 534' each have a surface perpendicular to the locking direction R and thus together form an undercut which effectively prevents subsequent compression of the vertebral body replacement 5.
[0140] Figures 14a to 14d show another embodiment of a vertebral body replacement 5, also according to the invention, which differs from that of Figures 13a to 13d in particular in that the locking structures 513 and 533 of the expansion carriage 51 and the expansion body 53 are slightly curved here to enable locking along a correspondingly curved locking direction R (see in particular Figures 14c and 14d). The vertebral body replacement 5 is thus better adapted to the anatomical conditions of a patient. Furthermore, the expansion body 53 of this embodiment has a bow-shaped, outwardly projecting intervention structure 536, which makes it possible to pull the locking teeth 534 away from the locking teeth 514 using a suitable tool, thereby canceling the mutual engagement of the locking structures 533 and 513 if necessary.The vertebral body replacement 5 can thus be shortened along the locking direction R, for example to remove the vertebral body 5 from the spine.
[0141] Figures 15a and 15b show an embodiment of a bone connection device according to the invention in the form of a polyaxial fixation system 1, which essentially corresponds to that of Figures 1a to 1f, but with the difference that the locking structures 133 and 153 here each have only two pairs of locking teeth 134, 134' and 154, 154', respectively. A pair of locking teeth 134, 134' of the locking structure 133 formed on the tulip head 13 is formed by the two locking teeth 134 and 134', which are arranged at the same height as the lateral webs 132 and 132'. Analogously, a pair of locking teeth 154, 154' of the locking structure 153 formed on the locking clamp 15 is formed by the two locking teeth 154 and 154', which are arranged opposite one another at the same height of the holding webs 152 and 152'. The embodiment with only two pairs of locking teeth 134, 134' or154, 154' has proven particularly advantageous in terms of the strength of the connection when the locking clamp 15 is snapped onto the tulip head 13. This can be explained by the fact that the mutual undercuts formed by the locking teeth 134, 134' and 154, 154' are larger due to the smaller number of locking teeth. Nevertheless, it is still possible to snap the locking clamp 13 onto the tulip head 15.The term "snap-on" should be understood to include the process or step of snapping the locking clip 13 onto the tulip head 15, and that in some embodiments, the engagement of the locking elements or locking teeth can be achieved by gradually snapping one set of locking elements or teeth over or around another set of locking elements or teeth, such that at least one locking element or tooth of the locking clip 13 and the tulip head 15 are engaged, and preferably, a plurality of locking elements or teeth of the locking clip 13 and the tulip head 15 are engaged. In principle, it is possible in all embodiments shown in Figures 1a to 17b to reduce or increase the number of locking teeth per locking structure. A number of only one or two locking teeth orOne or two pairs of locking teeth has proven particularly advantageous in terms of the strength of the connection. A number of at least three, at least five, or even at least ten locking teeth or pairs of locking teeth, however, offers the advantage that the first connecting element and the second connecting element can be locked together in several different positions.
[0142] Figures 16a and 16b show an embodiment of a polyaxial fixation system 1, i.e. a pedicle system, in which a connecting rod 11 is attached to a pedicle screw 12 by means of a locking clamp 15. However, the connecting rod 11 is not clamped between the locking clamp 15 and the tulip head 13, as in the exemplary embodiment of Figures 1a to 1f, but rather it is held by a connecting clamp 16, which is preferably connected in one piece to the rest of the locking clamp 15 via a web 161. The connecting clamp 16 itself forms a locking clamp. To clamp the washer 14 and the screw head 121, the locking clamp 15 here has an enlarged clamping element 155.The connecting clamp 16 has an internal locking structure 163, which is arranged on two retaining webs 162, 162' of the connecting clamp 16, which extend parallel to one another and have locking teeth 164, 164' arranged opposite one another. The locking teeth 164, 164' are designed to engage with locking teeth 113, which are formed by a locking structure 112 of the connecting rod 11. The locking structure 112 is in turn formed by a locking block 111, which is arranged at a free end of the connecting rod 11 and is integrally formed thereon. The connection between the connecting rod 11 and the pedicle screw 12 is thus established in particular via the web 161, which, due to its shape, has a certain degree of flexibility and thus allows certain movements between the connecting rod 11 and the screw 12.In this way, a gradual transition can be achieved between the section of the spine stiffened by the pedicle system and the adjacent, still mobile sections.
[0143] Figures 17a and 17b show a bone connection device according to the invention, designed as an axial connector system, according to yet another embodiment. Here, the locking structures 212 and 163 are each integrally connected to the first connecting rod 21 and the second connecting rod 22, respectively, or molded thereon. The first connecting rod 21 forms a locking block 211 at one of its free ends, which, similar to the first connecting rod 21 shown in Figure 10c, forms a locking structure 212 with locking teeth 213, 213' on the outside. However, the locking structure 212 extends further along the longitudinal direction of the connecting rod 21. A connecting clamp 16 is molded onto the free end of the second connecting rod 22, forming a locking clamp and connected to the remaining connecting rod 22 exclusively via a web 161.The connecting clamp 16 has a locking structure 163 on its inside with locking teeth 164 and 164', which are designed to lock into the locking teeth 213, 213' of the locking structure 211 formed on the first connecting rod 21. Since the locking structure 211 extends further along the longitudinal direction of the connecting rods 21 and 22 than the locking structure 163, the connecting rods 21 and 22 can be displaced relative to one another in the longitudinal direction over a limited range when locked together. Such mutual displaceability of the interconnected connecting rods 21, 22, limited by appropriate stops, can bring advantages depending on the application and have a positive effect on therapy. The connecting rods 21 and 22 of this and other embodiments can be straight or bent with any desired curvature.
[0144] Figures 18a and 18b as well as Figures 19a and 19b show further embodiments of bone connection devices according to the invention in the form of a pedicle system. In contrast to those in Figures 1a to 8b and 15a to 16b, the pedicle screws 12 are each fenestrated here. This allows, for example, bone cement to be introduced through the screw 12 to strengthen the bone in the corresponding area and / or to improve the anchoring of the screw 12 in the vertebra. Therefore, the screw 12 has several openings in the area of the screw tip 124, which communicate with an inner channel extending along the screw's longitudinal axis and open outward from this channel.In the embodiments of Figures 18a, 18b and 19a, 19b, the locking elements of the locking structure 133 formed on the tulip head 13 are not designed as locking teeth, as in the previously described embodiments, but rather as openings 139, 139'. The openings 139, 139' serve to engage the locking teeth 154, 154' of the locking clip 15, as shown in Figures 18a and 19a. For example, the openings 139, 139' can be in the form of slots, while the locking teeth 154, 154' of the locking clip can be designed to engage the slots. In the embodiment of Figures 18a and 18b, the locking clip 15 has a locking structure 153 with only two locking teeth 154, 154', which are arranged as a pair at the same height and directed outwardly away from each other. In one embodiment, the locking teeth 154, 154' can each be provided on a pair of flexible hooks or fingers of the clip 15.Analogously, the locking structure 133 of the tulip head 13 also has a locking structure 133 that has only two locking elements formed as openings 139, 139'. In one embodiment, the openings 139, 139' can be formed as slots for receiving the locking teeth 154, 154'. As shown, the clip 15 can be pressed onto the tulip head 13 so that the flexible hooks that encompass the locking teeth 154, 154' are slightly deformed so that the locking teeth 154, 154' can slide along the shaped inner guides of the tulip head 13 until they engage the openings 139, 139'.
[0145] In the embodiment of Figures 19a and 19b, the locking clip 15 has a locking structure 153 with a total of four locking teeth 154, 154', which are provided in the form of two pairs. In one embodiment, a pair of locking teeth 154, 154' can be provided on each pair of flexible hooks or fingers of the clip 15. The locking teeth 154 and 154' of each pair are arranged at the same height and face outwardly away from each other. Accordingly, the locking structure 133 of the tulip head 13 also has a locking structure 133 which has a total of four locking elements designed as openings 139, 139'. Analogous to the locking teeth 154, 154', the openings 139, 139' are also provided in the form of two pairs. Similar to the openings 139, 139' in Figures 18a and 18b, the openings 139, 139' can be designed as slots for receiving the locking tooth pairs 154, 154'.Similar to Figures 18a and 18b, the clip 15 can be pressed onto the tulip head 13 so that the flexible hooks comprising the pairs of locking teeth 154, 154' are slightly deformed to allow the pairs of locking teeth 154, 154' to slide along the shaped inner guides of the tulip head 13 until they engage the pairs of apertures 139, 139'.
[0146] The invention is not limited to the embodiments described above; rather, a multitude of modifications are possible. For example, in the polyaxial fixation system 1, the screw 12 could also be formed integrally with the tulip head 13. The locking clips 24 of the axial connector 23 could also be formed integrally, and the locking clip 34 of the parallel connector 33 could just as easily be formed in two parts, i.e., with one for each connecting rod 31, 32. The bone plate 41 could have any number of openings 412 for inserting one screw 42 each and / or be shaped in any other way. Different and / or additional elements from different embodiments can also be easily transferred or exchanged.For example, the locking clips 24 and 34, like the locking clips 15 shown in Figures 3, 5, 7, 8a, and 8b, can have one or more local recesses 157 for adjusting flexibility and / or an inner guide that interacts with an outer guide provided on the base body 231 or 331. It would of course also be conceivable in principle for the outer guide to be provided on the locking clip 15, 24, 34 and the inner guide to be provided on the tulip head 13 or on the base body 231 or 331. The mutual displaceability of the first connecting element and the second connecting element along the longitudinal direction of the locking teeth, corresponding to the embodiment shown in Figures 17a and 17b, is conceivable in principle for all embodiments. In particular, the locking structure 112 of the embodiment of Figures 16a and 16b could also be designed to be longer in order to enable a corresponding, preferably limited, longitudinal displacement.A large number of further modifications are conceivable.
[0147] LIST OF REFERENCE SYMBOLS
[0148] I Polyaxial fixation system internal guide
[0149] 159 Intervention structure
[0150] II Connecting rod
[0151] III Locking block 16 Connecting clamp
[0152] 112 locking structure 161 web
[0153] 113 locking teeth 162, 162' retaining web
[0154] 163 locking structure
[0155] 12 screw 164 164 - locking teeth
[0156] 121 screw head
[0157] 122 Engagement structure 2 Axial connector system
[0158] 123 threaded shaft
[0159] 21 First connecting rod
[0160] 124 screw tip
[0161] 211 Rest block
[0162] 13 Tulip head 212 locking structure
[0163] 131 Base body 213, 213' locking teeth
[0164] 132, 132' Side web 22 Second connecting rod
[0165] 133 locking structure 221 locking block
[0166] 134, 134' locking teeth 222 locking structure
[0167] 135, 135' receiving opening 223, 223' locking teeth
[0168] 136 Interior
[0169] 23 Axial connector
[0170] 137 contact area
[0171] 231 basic body
[0172] 138, 138' dovetail opening
[0173] External tour 232, 232
[0174] 233 233' resting structure 139, 139' openings '
[0175] 234, 234' ratchet teeth
[0176] 14 Washer 235, 235' interior
[0177] 236, 236' contact area
[0178] 15 locking clip
[0179] 151 Connecting bar 24 Locking clip
[0180] 152, 152' Holding bridge 241 Connecting bridge
[0181] 153 Rest structure 242, 242' Holding bridge
[0182] 154, 154' locking teeth 243 locking structure
[0183] 155 clamping element 244, 244' locking teeth
[0184] 156, 156' slot 245 clamping element
[0185] 157 Deepening 246 Deepening
[0186] 158, 158' Dovetail 247 connecting section 425 engagement structure
[0187] Parallel connector system 426 threaded shaft
[0188] 427 screw tip
[0189] First connecting rod
[0190] 428 Longitudinal center axis Second connecting rod
[0191] 5 Vertebral body replacement
[0192] Parallel connector base body 51 Expansion slide, 332' Receiving opening 511 Base body locking structure 512 Connecting structure, 334' Locking teeth 513 Locking structure, 335' Interior 514, 514' Locking teeth, 336' Contact surface
[0193] 52 cover plate
[0194] Locking clamp 521 base body
[0195] Connecting bar 522 Connecting structure, 342' Holding bar 523 Upper bone contact surface Locking structure 524 Notch, 344' Locking teeth, 345' Clamping element 53 Expansion body
[0196] 531 basic body
[0197] Cervical plate system 532 connection structure
[0198] 533 locking structure
[0199] bone plate
[0200] 534, 534' locking teeth base body
[0201] 535 slot opening
[0202] 536 Intervention structure locking structure locking teeth 54 Base plate longitudinal center axis 541 Base body
[0203] 542 connection structure
[0204] screw
[0205] 543 Lower bone contact surface screw head
[0206] 544 Notch Slot
[0207] Locking structure R Locking direction Locking teeth
Claims
PATENT CLAIMS 1. A medical bone connecting device (1; 2; 3; 4; 5) for connecting two bones or bone parts of a human or animal patient, comprising a first connecting element (13; 21, 22; 23; 33; 42; 51) made of a fiber-reinforced plastic material, which has a first locking structure (133; 212, 222; 233, 233'; 333; 423; 513) with a plurality of first locking elements (134, 134'; 139, 139'; 213, 213', 223, 223'; 234, 234', 334, 334'; 424; 514, 514'); and a second connecting element (15; 24; 34; 41; 53) made of a fiber-reinforced plastic material, which has a second locking structure (153; 243; 343; 413; 533) with a plurality of second locking elements (154, 154'; 244, 244'; 344, 344'; 414; 534, 534'); wherein the first locking elements (134, 134'; 139, 139'; 213, 213', 223, 223'; 234, 234', 334, 334'; 424; 514, 514') of the first locking structure (133; 212, 222; 233, 233'; 333; 423;513) can be locked to the second locking elements (154, 154'; 244, 244'; 344, 344'; 414; 534, 534') of the second locking structure (153; 243; 343; 413; 533) in order to fix the first connecting element (13; 21, 22; 23; 33; 42; 51) and the second connecting element (15; 24; 34; 41; 53) to one another and thereby connect the two bones or bone parts to one another.
2. Bone connecting device (1; 2; 3; 4; 5) according to claim 1, wherein the first locking elements (134, 134'; 139, 139'; 213, 213', 223, 223'; 234, 234', 334, 334'; 424; 514, 514') and the second locking elements (154, 154'; 244, 244'; 344, 344'; 414; 534, 534') are each designed with an undercut such that a release of the fixation between the first connecting element (13; 21, 22; 23; 33; 42; 51) and the second connecting element (15; 24; 34; 41 ; 53) is prevented when the first locking structure (133; 213, 213', 223, 223'; 233, 233'; 333; 423; 513) and the second locking structure (154, 154'; 244, 244'; 344, 344'; 414; 534, 534') are locked together.
3. Bone connecting device (1; 2; 3; 4; 5) according to claim 1 or 2, wherein the first locking elements (134, 134'; 139, 139'; 213, 213', 223, 223'; 234, 234', 334, 334'; 424; 514, 514') and / or the second locking elements (154, 154'; 244, 244'; 344, 344'; 414; 534, 534') each have an inclined surface inclined to a locking direction (R) in order to facilitate locking of the first locking structure (133; 212, 222; 233, 233'; 333; 423; 513) with the second locking structure (154, 154'; 244, 244'; 344, 344'; 414; 534, 534').
4. Bone connection device (1; 2; 3; 4; 5) according to one of the preceding claims, wherein the first locking structure (133; 212, 222, 233, 233'; 333; 423; 513) is an inner locking structure whose first locking elements (134, 134'; 139, 139'; 213, 213', 223, 223'; 234, 234', 334, 334'; 424; 514, 514') are directed outwards in at least two opposite directions, and wherein the second locking structure (154, 154'; 244, 244'; 344, 344'; 414; 534, 534') is an outer locking structure whose second locking elements (154, 154'; 244, 244'; 344, 344'; 414; 534, 534') are directed inwards in at least two opposite directions.
5. Bone connection device (1; 2; 3; 4; 5) according to claim 4, wherein the Bone connecting device (1; 2; 3; 4; 5) a third connecting element (11; 21, 22; 31, 32), and wherein the second connecting element is a locking clamp (15; 24; 34) which serves to clamp the third connecting element (11; 21, 22; 31, 32) between the first connecting element (13; 23; 33) and the second connecting element (15; 24; 34).
6. Bone connecting device (1; 2; 3; 4; 5) according to claim 5, wherein the locking clip (15; 24; 34) has a clamping element (155; 245; 345, 345') which is arranged within the second locking elements (154, 154'; 244, 244'; 344, 344').
7. Bone connecting device (1; 2; 3; 4; 5) according to claim 5 or 6, wherein the locking clip (15; 24; 34) has a local recess (157) for adjusting its flexibility in a region between the inwardly facing second locking elements (154, 154'; 244, 244'; 344, 344').
8. Bone connecting device (1; 2; 3; 4; 5) according to one of claims 5 to 7, wherein the third connecting element is a connecting rod (11) and the first connecting element is a tulip head (13) which serves to fix the connecting rod (11) to a threaded shaft (123) of a screw (12), in particular a pedicle screw.
9. Bone connecting device (1; 2; 3; 4; 5) according to one of claims 5 to 7, wherein the third connecting element is a connecting rod (21, 22; 31, 32) and the first connecting element is a connector, in particular an axial connector (23) or a parallel connector (33), for connecting two connecting rods (21, 22; 31, 32).
10. Bone connecting device (1; 2; 3; 4; 5) according to claim 9, wherein the connector (23; 33) has at least one opening (232, 232'; 332, 332') for receiving the connecting rod (21, 22; 31, 32), which widens along a locking direction (R) towards the second connecting element.
11. Bone connection device (1; 2; 3; 4; 5) according to claim 4, wherein the first connecting element is a screw (42) and the second connecting element is a bone plate (41), and wherein the screw (42) has an at least partially elastically deformable screw head (421) on which the first locking structure (423) is formed, and the first locking elements (424) and / or the second locking elements (414) preferably form a thread.
12. Bone connecting device (1; 2; 3; 4; 5) according to one of claims 1 to 4, which is designed as a vertebral body replacement (5), wherein the first connecting element is an expansion slide (51) and the second connecting element is an expansion body (53).
13. Bone connecting device according to one of the preceding claims, wherein the first connecting element (13) and the second connecting element (15) have interengaging guides (138, 138', 158, 158'), which preferably together form a Form a dovetail joint in order to guide the first locking structure (133) relative to the second locking structure (153) during fixing.
14. Bone connection device according to one of the preceding claims, wherein the second connecting element has a locking clip which forms the second locking structure, and wherein the locking clip is connected to the remaining second connecting element via a flexible element.
15. Bone connection device according to one of the preceding claims, wherein the second connecting element has a locking clip, and wherein the first connecting element and the second connecting element, in the locked state, are displaceable relative to one another along the longitudinal direction of the first and second locking elements over preferably a limited range.
16. A method for connecting two bones or bone parts of a human or animal patient, in particular by means of a bone connecting device (1; 2; 3; 4; 5) according to one of the preceding claims, wherein a first connecting element (13; 21, 22; 23; 33; 42; 51) made of a fiber-reinforced plastic material and a second connecting element (15; 24; 34; 41; 53) made of a fiber-reinforced plastic material are fixed to one another by a plurality of first locking elements (134, 134'; 139, 139'; 213, 213', 223, 223'; 234, 234', 334, 334'; 424; 514, 514') of a first locking structure (133; 212, 222; 233, 233'; 333; 423; 513) of the first connecting element (13; 21, 22; 23; 33; 42; 51) is locked to a plurality of second locking elements (154, 154'; 244, 244'; 344, 344'; 414; 534, 534') of a second locking structure (153; 243; 343; 413; 533) of the second connecting element (15; 24; 34; 41; 53).
Citation Information
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