IMPLANT SYSTEM

Description

[0001] The present invention relates to an implant system for treating fractures of a curved bone structure, in particular broken ribs in the thoracic region. Furthermore, the invention relates to a method for producing such an implant system.

[0002] US 2021 / 0298808 A1 discloses a sternal replacement plate with a central region and rod-like extensions. The extensions are thicker than the central region, allowing the central region to bend around a bending axis. US 2005 / 085814 A1 relates to an orthopedic device for attaching multiple bone parts to one another, in particular the spine. The device comprises a rod-like main structure, both ends of which are provided with attachment structures (e.g., holes into which bolts can be inserted). The ends are connected by a rotatable and extendable connector that allows relative rotation and extension of the ends. The connector is coated with a biodegradable reinforcement material that resists the movement of the ends and gradually yields as the reinforcement material is resorbed.

[0003] US 2012 / 203284 A1 describes a fastening device with locking means at both ends and a connecting structure in the middle that can be stretched like an accordion. This allows the distance between the ends to be adjusted. US 2018 / 0360506 A1 discloses a bone fixation device with two rigid end pieces connected by an elastic connecting area made of wires.

[0004] Thoracic trauma is defined as an injury to the bony rib cage and all organs and organ systems within it. Thoracic trauma typically occurs as a result of significant force involving injuries to multiple body regions.

[0005] While isolated chest trauma is rare, almost half of patients suffering from multiple trauma suffer from simultaneous chest trauma. A polytrauma occurs when multiple body regions or organ systems are affected simultaneously, with one of the injuries alone or the combination of injuries being life-threatening.

[0006] The thorax consists of the thoracic spine, the sternum, and 12 paired ribs. Cranially, the thorax is bounded by the upper thoracic inlet, which is formed by the first thoracic vertebra, the first two ribs, and the upper portion of the sternum.

[0007] It represents the connection between the connective tissue spaces of the neck and the thorax. The caudal border of the thorax, the lower thoracic inlet, represents the boundary between the thoracic and abdominal cavities. It is formed by the 12th thoracic vertebra, the 11th and 12th ribs, the cartilage portions of the 7th to 10th ribs, and the lower border of the sternum. The boundary structure between the thoracic and abdominal cavities is the diaphragm, which stretches between these skeletal structures. The ribs are connected to the spine via so-called costovertebral joints, and to the sternum via so-called sternocostal joints.

[0008] In conjunction with the rib cage muscles, which fill the intercostal spaces between the ribs, the joints play a central role in respiratory mechanics. Since the rib cage also houses vital organs such as the heart, lungs, and important vascular pathways, it also serves as a protective framework.

[0009] During inhalation, the ventral sternal rib ends are raised by stretching the rib heads in the costovertebral joints. At the same time, the diaphragm contracts and lowers. This results in an increase in the volume of the thorax. During exhalation, the ventral sternal rib ends descend again and the diaphragm muscles relax, thus allowing the thorax to return to its original volume. Of all fractures in the thorax, rib fractures are the most common.

[0010] Fractures such as those of the ribs can be treated and reconstructed using metal implants. Kirschner wires, for example, are known for their ability to fix the fractures in question through a process known as K-wire osteosynthesis. However, these can migrate into the bone after insertion, particularly into bone cavities, and are not immune to failure. Furthermore, the use of K-wires for immobilization often requires additional plaster cast fixation, which complicates the treatment of thoracic trauma.

[0011] Metal splints are also known for fracture treatment, but they provide only inadequate pain relief. This cannot be completely achieved with rib fractures, even with rib clamps, which also do not allow controlled movement in the fracture gap. Overall, primary bone healing is significantly hampered in this case as well.

[0012] Another option for fixating the aforementioned fractures is plate osteosynthesis using plates or splints. In this context, DE 38 03 435 C1 describes an implant splint with a lateral surface adapted to the contour of a rib. A disadvantage of plate osteosynthesis is that the stiffness of the implant can impair the respiratory mechanics of the rib thorax. Furthermore, particularly in osteoporotic bones, loosening of screw-like fixations at the transition to the non-rigid rib region can occur.

[0013] It is therefore the object of the present invention to provide an implant system which treats a fracture in a bone structure safely and without failure and at the same time enables controlled movement in the fracture gap with good bone healing and pain elimination.

[0014] The problem is solved by an implant system having the features of claim 1.

[0015] With the implant system according to the invention, an implant body can be arranged on the curved bone structure in a manner that, for example, replicates the curvature of the bone structure through bending or at least partially encloses or wraps around the bone structure through torsion of the at least one central piece, so that on the one hand the fragments of the bone structure are securely held and on the other hand a controlled movement of the bone structure as a whole is enabled without hindering the healing process. The implant system therefore enables a controlled elastic movement behavior of the affected bone fragments of the bone structure. Due to the elastic design of the at least one central piece, the holding pieces can be arranged in different positions relative to one another on the bone structure and, if necessary, secured, while the central piece(s) is flexibly molded to the bone structure.The implant system according to the invention is particularly suitable for the treatment of damaged bone structures in the thoracic region, i.e. rib bones, but is not limited thereto.

[0016] Preferred developments of the implant system according to the invention can be found in the corresponding subclaims.

[0017] A design with a central piece and two holding pieces located at its ends has already been described, but other configurations are also conceivable. For example, further elastic central pieces can be arranged after the holding pieces, followed by further holding pieces. Omitting one or more of the respective pieces is also conceivable, so that a series of central and holding pieces is conceivable, which can encompass or wrap around a wide variety of bone structures with varying circumferences and large longitudinal extensions, one or more times.

[0018] In an advantageous development of the implant system according to the invention, which exhibits high flexibility and good handling with regard to the arrangement of the implant body on the bone structure, the implant body, with its rod-like longitudinal extension, can have at least one region whose lateral edges are wave-shaped, in particular uniformly wave-shaped, on at least two opposite sides. In this case, both the at least one central piece and one or more retaining pieces can be configured individually or jointly with the aforementioned wave shape.

[0019] Particularly preferably, in a simplified manufacturing development, the at least one center piece and the at least two holding pieces can have substantially the same outer contour, for example, each having the identical, uniform wave shape on its side edges. However, the holding pieces can differ in shape both from each other and from the at least one center piece.

[0020] One possibility for adapting the properties of the implant body of the implant system according to the invention to the specific bone structure and its degree of damage is, in an advantageous further development, for the thickness and / or length of the holding pieces and / or the center piece to be different and / or variable. The variability of the holding pieces and / or center pieces allows the respective implant body to be individually adapted by measuring the respective situation. In simplified further developments of implant bodies, for example, the holding pieces can be designed identically in pairs.

[0021] In a further development in which, on the one hand, the middle piece has a high degree of flexibility and, on the other hand, the holding pieces are designed to be very stable, the holding pieces can be designed with an increased thickness compared to the at least one middle piece, so that they show reduced flexibility.

[0022] In order to be able to connect the central piece and the holding pieces of the implant body in a manner that does not have unnecessary projections or steps, particularly when the pieces have different thicknesses, and to provide the holding pieces with a preferred orientation relative to the at least one central piece by angling them, if necessary or desired, an advantageous development of the implant system according to the invention can provide a transition region between at least one of the holding pieces and the at least one central piece. For this purpose, for example, the transition region can have at least one section that is angled relative to the longitudinal extent; however, the transition region can also form a simple taper of the thickness of the cross-section from the thickness of the at least one central piece to that of the respective holding piece.A transition region is also conceivable in which a flat side of the at least one central piece and the holding pieces, in particular the flat side for contact with the bone structure, lie in one plane.

[0023] With regard to their dimensions, both the central piece and the holding pieces should, in principle, initially be subject to no restrictions other than those of the environment in which they are used. However, certain dimensions are particularly preferred with regard to individual directions of extension. For example, the length of the implant body can preferably be between 1 mm and 300 mm, the length of at least one central piece can be between 1 mm and 50 mm, its thickness can be between 0.1 mm and 3.5 mm, while the thickness of the holding pieces can be between 0.5 mm and 4.5 mm. The corners formed by a wave-shaped design of the side edges of the implant body can have roundings in the range between 0.01 and 4.5 mm. Furthermore, it is conceivable that the aforementioned dimensions can vary across their respective directions of extension.

[0024] In order to hold the implant body stationary in a simple manner in an expedient further development of the implant system according to the invention, at least one fastening means can be arranged between the implant body and the bone structure.

[0025] Preferably, the at least one fastening means is formed with one or a number of protrusions, hooks, or similar projections that are designed to penetrate the bone structure. Such projections can be provided both on the at least one central piece and on the two holding pieces, and can be arranged both on the side facing the bone structure, where they penetrate the bone structure, and on the side facing away from the bone structure, where they are capable of fixing the surrounding tissue. Another preferred development can consist in screws engaging through receptacles provided for this purpose on one or more of the holding pieces, thus securing them to the bone structure. Receptacles for the penetration of screws or similar fastening means can also be provided on the central pieces.

[0026] In order to be able to adapt the respective, optionally individually manufactured implant body to the respective situation in a suitable manner, for example with regard to specifically selected material properties such as fatigue resistance, flexibility, ideal elastic modulus, or strength, according to the invention the implant body of the implant system is formed from at least one high-performance polymer or composites thereof. Particularly preferably, the at least one central piece and the holding pieces can each be formed from a thermoplastic material such as a polyetheretherketone (PEEK) material, a polyetherketoneketone (PEKK) material, a polyphenylsulfone (PPSU) material, a polyethylene (PE) material, as well as from so-called compounds of the above-mentioned materials with hydroxyapatite, tricalcium phosphate, strontium, magnesium, and the like. However, other materials are also conceivable, and the above list is not exhaustive.

[0027] Particularly when the implant body is manufactured individually, for example to treat more complicated fractures or those with a poorer healing prognosis, the at least one central piece and the holding pieces can have a surface adapted to the respective bone area on their surface facing the bone structure, which allows for even more precise adaptation.

[0028] The above object is also achieved by a method for producing an implant system for treating fractures of a curved bone structure according to claim 12.

[0029] It is also conceivable to produce the final shape of the implant body as well as the final design of the at least one elastic central piece by post-processing a blank of the implant body obtained in a primary forming process. Such post-processing can, for example, consist of a separation process in which material layers of chips are mechanically separated from the blank using the cutting edges of a tool to change the workpiece shape and / or surface. The cutting can be performed, for example, using geometrically defined cutting edges as a milling process, whereby a high level of manufacturing accuracy can be achieved with such a manufacturing process.

[0030] In this way, an implant system can also be provided that treats a fracture in a bone structure safely and without failure and at the same time enables controlled movement in the fracture gap with good bone healing and pain elimination.

[0031] The invention is explained in more detail below using exemplary embodiments in the figures of the drawing. In a partially schematic representation, the figures show: Fig. 1a a perspective side view of a first embodiment of the implant system according to the invention with an implant body in an elongated form; Fig. 1b a perspective side view of the implant body from the Fig. 1a in a form bent around a bending axis, Fig. 1c a perspective side view of the implant body arranged on the bone structure of a rib arch from the Fig. 1a ; Fig. 1a perspective side view of the implant body from the Fig. 1c in view from below; Fig. 2a a perspective side view of a second embodiment of the implant system according to the invention with an implant body in an elongated form, in which the holding pieces are provided with points on the flat side facing away from the bone structure, but the middle piece has no points; Fig. 2b a perspective side view of a detailed area of ​​one holding piece of the implant body from the Fig. 2a ; Fig. 2c a perspective side view of the implant body from the Fig. 2a und 2b in which both the holding pieces and the middle piece are provided with points on the flat side of the implant body facing away from the bone structure; Fig. 3a a perspective side view of a third embodiment of the implant system according to the invention with an implant body in elongated form, in which the middle piece is provided with points on the flat side facing away from the bone structure; Fig. 3b a perspective side view of a detailed area of ​​the middle piece of the implant body from the Fig. 3a ; Fig. 3c a perspective side view of the implant body from the Fig. 3a and 3b in which only the central piece is provided with points on the flat side of the implant body facing the bone structure and the surfaces of the central piece and the holding pieces lie in one plane; Fig. 3d a perspective side view of a detailed area of ​​the central piece of the implant body from the Fig. 3a-3c ; Fig. 4 is a perspective side view of a fourth embodiment of the implant system according to the invention with an implant body in an elongated form, in which the holding pieces are formed with a wave shape at their side edges, while the central piece extends with parallel, straight side edges; and Fig. 5 is a perspective side view of a fifth embodiment of the implant system according to the invention with an implant body in an elongated form, in which the holding pieces are formed with substantially straight, parallel side edges at their side edges, while the central piece extends straight but with wave-shaped side edges.

[0032] In all figures, identical or functionally identical elements and devices are provided with the same reference numerals, unless otherwise indicated.

[0033] The drawing figures 1 to 5 show an implant system 100 for treating fractures of a curved bone structure 50, which comprises the following: an implant body 10, which is intended to be arranged on the bone structure 50 and to contact it at least in some areas, wherein the implant body 10 has a rod-like longitudinal extension, wherein the implant body 10 has at least one central piece 12, which has at least one respective holding piece 14, 16 at both ends, wherein the holding pieces 14, 16 are each designed to be flexurally and / or torsionally rigid in such a way that a substantially planar contact of the respective holding piece 14, 16 along a region of the bone structure 50 assigned to it is possible, and wherein the at least one central piece 12 is designed to be elastic in such a way that the at least two holding pieces 14, 16 are bendable relative to one another about at least one bending or torsion axis.

[0034] The Fig. 1a shows a perspective side view of a first embodiment of the implant system 100 according to the invention with an implant body 10 in an elongated form. The implant body 10 is designed with a rod-like longitudinal extension and is provided with side edges on both the central piece 12 and the two holding pieces 14, 16, which have the same outer contour, which side edges are uniformly undulating on two opposite sides. Due to the undulating shape, protruding and recessed sections are formed on the side edges, alternating into one another, wherein a recessed section of one side edge corresponds to a projecting section of the opposite side edge. In the projecting sections of the holding pieces 14, 16, receptacles 17 for the arrangement of fastening screws (not shown) are introduced perpendicular to the longitudinal extension.Between the holding pieces 14, 16 and the central piece 12, a transition area 18 is arranged, creating a smooth transition between the holding pieces 14, 16, which are thicker perpendicular to the longitudinal extent, and the thinner central piece 12. The transition pieces transfer the levels of the flat sides of the holding pieces 14, 16, which are aligned with each other when the implant body 10 is not bent, into that of the central piece 12.

[0035] The Fig. 1b shows a perspective side view of the implant body 10 from the Fig. 1a in a form bent around a bending axis, wherein the bending axis (not shown) runs centrally in the plane spanned by the central piece 12 and transversely to the longitudinal extent of the implant body 10.

[0036] The Fig. 1c shows a perspective side view of the implant body 10 arranged on the damaged bone structure 50 of a rib arch from the Fig. 1a The damage to the bone structure 50 in the form of a fracture is clearly visible. Furthermore, one can see one of the holding pieces 14, which is fixed to the bone structure 50, and also the central piece 12, which is rotated about a torsion axis running along the bone structure such that the implant body 10 wraps around the bone structure 50 by approximately 180°. Fig. 1d shows a perspective side view of the implant body from the Fig. 1c in view from below, in which both holding pieces 14, 16 and the middle piece 12 can be seen. In the Fig, 1c und 1d It can further be seen that the holding pieces 14, 16 are spaced from the fracture itself and the central piece 12 wraps around or encompasses this area in such a way that a controlled movement and load distribution of the dynamic chest cavity is promoted, thereby promoting bony healing.

[0037] The Fig. 2a shows a perspective side view of a second embodiment of the implant system 100 according to the invention with an implant body 10' in an elongated form, in which the holding pieces 14', 16' are provided with points 22' as fastening means 20' on the flat side facing away from the bone structure 50 (not shown), but the central piece 12 does not have points 22' on its flat side. The central piece 12' and the holding pieces 14', 16' of the implant body 10', which again has a rod-like longitudinal extension, are again provided with side edges that are uniformly undulating on two opposite sides. Here, too, a transition region 18' is arranged between the holding pieces 14', 16' and the central piece 12', at which a step-free transition is created between the thicker holding pieces 14', 16' and the thinner central piece 12'.

[0038] The Fig. 2b shows a perspective side view of a detailed area of ​​one holding piece 14' of the implant body 10' from the Fig. 2a , in which it can be seen that the tips 22' are arranged in the extension direction of the implant body 10' along a line between the projecting and recessed sections in groups of three tips 22' each. Here, too, receptacles 17' for arranging fastening screws (not shown) are introduced into the projecting sections of the holding pieces 14', 16' perpendicular to the longitudinal extension.

[0039] The Fig. 2c shows a perspective side view of the implant body 10' from the Fig. 2a und 2b in which, on the flat side of the implant body 10' facing away from the bone structure, both the holding pieces 14', 16' and the central piece 12' are provided with tips 22', whereby the tissue surrounding the implant body 10' is held stationary.

[0040] The Fig. 3a shows a perspective side view of a third embodiment of the implant system 100 according to the invention with an implant body 10" in an elongated form, in which the central piece 12" is provided with points 22" on the flat side facing away from the bone structure. The implant body 10" is again formed with a rod-like longitudinal extension and is provided with side edges on both the central piece 12" and the two holding pieces 14", 16" having the same outer contour, which are uniformly undulating on two opposite sides. Due to the undulating shape, protruding and recessed sections are formed on the side edges, alternating between one another, wherein a recessed section of one side edge coincides with a projecting section of the opposite side edge.In the projecting sections of the holding pieces 14", 16", receptacles 17" are inserted perpendicular to the longitudinal extension for the arrangement of fastening screws (not shown).

[0041] The Fig. 3b shows a perspective side view of a detail area of ​​the center piece 12" of the implant body 10" from the Fig. 3a . It can be seen that the 22" tips on the 12" center piece are arranged individually on each projecting section.

[0042] The Fig. 3c shows a perspective side view of the implant body 10" from the Fig. 3a and 3b in which only the central piece 12" is provided with tips 22" on the flat side of the implant body 10" facing the bone structure, the surfaces of the central piece 12" and the holding pieces 14", 16" lying in one plane.

[0043] The Fig. 3d shows a perspective side view of a detail area of ​​the center piece 12" of the implant body 10" from the Fig. 3a-3c .

[0044] The Fig. 4 shows a perspective side view of a fourth embodiment of the implant system 100 according to the invention with an implant body 10‴ in an elongated form, in which the holding pieces 14‴, 16‴ are formed with a wave shape on their side edges, while the central piece 12‴ extends with parallel, straight side edges. Here, too, a transition region 18‴ is arranged between the holding pieces 14‴, 16‴ and the central piece 12‴. With regard to the wave shape of the holding pieces 14‴, 16‴ and the receptacles 17‴ for fastening means, reference can be made to the Fig. 1 bis 3 What has been said is referred to.

[0045] The Fig. 5shows a perspective side view of a fifth embodiment of the implant system 100 according to the invention with an implant body 10"" in an elongated form, in which the holding pieces 14"", 16"" are formed with essentially straight, parallel side edges on their side edges, while the central piece 12"" extends straight but with wavy side edges. The receptacles 17"" for arranging fastening screws have the same pattern as with a wavy design of the side edge, and at the ends of the holding pieces 14"", 16"" their side edges each converge at a receptacle 17""

[0046] The implant system 100 according to the invention solves the problem mentioned above by combining an innovative and flexible design with specifically selected material properties such as fatigue resistance, flexibility, ideal elastic modulus, and material strength. This ensures controlled load distribution and controlled movement of the dynamic thoracic cavity, which promotes bone healing in contrast to a more rigid metallic system.

Claims

1. Implant system (100) consisting of at least one high performance polymer or composites thereof for treating fractures of a curved bone structure (50), comprising an implant body (10, 10', 10'', 10‴, 10""), which is provided to be arranged on the bone structure (50) and to make contact with it at least in areas, wherein the implant body (10, 10', 10'', 10''', 10"") has a rod-like longitudinal extension, wherein the implant body (10, 10', 10'', 10‴, 10"") has a centre piece (12, 12', 12'', 12''', 12"") which has a respective retaining piece (14, 14', 14'', 14‴, 14"", 16, 16', 16'', 16‴, 16"") on both ends, wherein the retaining pieces (14, 14', 14'', 14''', 14"", 16, 16', 16'', 16‴, 16"") are respectively designed to be resistant to bending and / or torsion in such a way that substantially planar contact of the respective retaining piece (14, 14', 14'', 14‴, 14"", 16, 16', 16'', 16‴, 16"") along a region of the bone structure (50) associated therewith is enabled, and wherein the centre piece (12, 12', 12'', 12‴, 12"") is designed to be elastic in such a way that the at least two retaining pieces (14, 14', 14'', 14‴, 14"", 16, 16', 16'', 16‴, 16"") can be bent relative to one another about a bending axis and a torsion axis such that the bone structure (50) can be embraced by the centre piece (12, 12', 12", 12‴, 12"") at least in areas.

2. Implant system (100) according to claim 1, wherein the implant body (10) with its rod-like longitudinal extension has at least one region, the side edges of which are formed in an undulating manner, in particular a uniformly undulating manner, on at least two opposites sides.

3. Implant system (100) according to one of Claims 1 or 2, wherein the centre piece (12, 12', 12'', 12‴, 12"") and the two retaining pieces (14, 16) have substantially the same outer contour.

4. Implant system (100) according to one of the preceding claims, wherein the thickness and / or length of the retaining pieces (14, 16) and / or centre piece (12, 12', 12'', 12‴, 12"") vary.

5. Implant system (100) according to one of the preceding claims, wherein the retaining pieces (14, 16) are designed with an increased thickness compared to the centre piece (12, 12', 12", 12‴, 12"").

6. Implant system (100) according to one of the preceding claims, wherein a transition region (18, 18', 18'', 18''', 18"") is provided between at least one of the holding pieces (14, 16) and the centre piece (12, 12', 12'', 12‴, 12"").

7. Implant system (100) according to claim 6, wherein the transition region (18, 18', 18'', 18‴, 18"") has at least one section angled relative to the longitudinal extension.

8. Implant system (100) according to one of the preceding claims, wherein at least one fastening means (20', 20'') is arranged on the implant body (10', 10'').

9. Implant system (100) according to claim 8, wherein the fastening means (20', 20'') is formed with one or a number of spikes, points (22', 22''), hooks or such protrusions, which are designed to penetrate into a bony structure of the bone structure (50) or hold tissue surrounding the implant body (10', 10'') in place.

10. Implant system (100) according to one of the preceding claims, wherein the at least one high performance polymer is made of a thermoplastic material such as a polyetheretherketone (PEEK) material, polyetherketoneketone (PEKK) material, a polyphenylsulfone (PPSU) material, a polyethylene (PE) material as well as compounds of the aforementioned materials with hydroxyapatite, tricalcium phosphate, strontium, magnesium, and the like.

11. Implant system (100) according to one of the preceding claims, wherein the centre piece (12, 12', 12'', 12‴, 12"") and the retaining pieces (14, 14', 14'', 14''', 14"", 16, 16', 16", 16‴, 16"") have a surface adapted to the respectively associated bone region on their surface respectively facing the bone structure (50).

12. Method for producing an implant system (100) according to one of the preceding claims for treating fractures of a curved bone structure (50), comprising at least the following production steps: - providing an implant body mould which is divided into at least three different regions, a central region and an end region located at each of its ends; - injecting at least one high performance polymer into each of the regions of the implant body mould; - cooling and / or cross-linking the high performance polymers in the various regions while joining the regions to form the rod-shaped, flexible implant body (10, 10', 10'', 10‴, 10"") with the elastic centre piece (12, 12', 12", 12‴, 12"") and the two retaining pieces (14, 14', 14'', 14‴, 14"", 16, 16', 16'', 16‴, 16""), which can be bent relative to one another about the one bending axis and the one torsion axis; - removing the implant body (10) from the implant body mould.