DE102021211683A1 - Fastening device for implants or tissue fragments - Google Patents

Abstract

The invention provides a fastening device (100) for implants or tissue fragments (2) on hard tissue (1), and a system for fastening an implant or a tissue fragment (2). The fastening device (100) includes:
an elongate anchor element (120) which can be inserted into the hard tissue (1) along its longitudinal axis (A) in order to fix the fastening device (100) to the hard tissue (1); and
a planar head element (110) which cantilevers at one end of the anchor element (120);
wherein at least one non-continuous recess (130) extends from an outer side (111) of the head element (110), which is a surface of the head element (110) facing away from the anchor element (120), into the anchor element (120).

Description

technical field

The present invention relates to a fastening device for implants or tissue fragments on hard tissue and a system for fastening an implant or a tissue fragment on hard tissue.

Background of the Invention

The fixation of large-area membrane-like implants or of soft implants such as collagen membranes, hydrogel or the like, or of endogenous hard or soft tissue structures with traditional mounting devices such as screws, pins, nails, staples or wire represents a major challenge. Often these solutions do not allow for spatially optimal healing of the damaged tissue without slipping in one of the three spatial directions. In addition, with some fixation systems, in particular those made of metal, another difficulty arises, namely that thumbtack-like constructs can damage or even destroy soft or very filigree implants to be fixed. Functional failure of such implants can occur, particularly in marginal areas.

Especially with large and flat structures to be implanted, extensive tears, formation of gaps or fractures can occur, for example due to the application-related introduction of fixation elements or due to biomechanical aspects of the implants to be fixed. In addition, when such structures are attached, mechanical situations can occur which result in damage to the entities to be implanted or fixed, since the force distribution during fixation can only be distributed to a limited extent and strong mechanical forces can act at the same time.

Known from the prior art is, for example, the shielding screw, which acts as a cavity-generating construct and causes fixation in the Z direction, i.e. in the direction perpendicular to a planar implant or tissue fragment, but no fixation in the X/Y direction, i.e. parallel to expand the implant or tissue fragment. Also known are nails or thumbtack-like implants, which usually consist of metallic components.

From the WO 2017/089381 A1 a bioresorbable fixation nail is known. This fixation nail has a round and flat nail head and a nail pin that is preferably longer compared to the diameter of the nail head. The nail pin may have a barb and serves to be driven into a bone, whereby a transplantable tissue is to be fixed between an underside of the nail head and the bone in the longitudinal direction of the fixation nail. This design has several disadvantages, particularly in relation to trauma that may occur, for example, at the edges of the device and/or when the device is inserted into the bone.

Summary of the Invention

It is an object of the present invention to provide an improved fastening device for implants or tissue fragments on hard tissue, which has the most atraumatic effect possible both when it is being introduced into the bone and when it is being used. This object is achieved by a fastening device with the features of patent claim 1, which also has other advantages. Furthermore, the object is to provide a system for fastening an implant or a tissue fragment which acts as atraumatic as possible both when fastening the implant or tissue fragment to the hard tissue and during the healing process. This problem is solved by a system with the features of patent claim 10 .

Accordingly, according to a first aspect of the present invention, there is provided a fixation device for implants or tissue fragments to hard tissue, comprising: an elongate anchor element insertable into the hard tissue along its longitudinal axis for fixing the fixation device to the hard tissue; and a planar head member overhanging at one end of the anchor member.

Advantageously, at least one non-continuous recess extends from an outside of the head element, which is a surface of the head element facing away from the anchor element, into the anchor element. This recess advantageously serves, on the one hand, to insert the fastening device into the hard tissue using a corresponding specific tool, and, on the other hand, to stabilize the fastening device. As will be described in more detail below, a plurality of non-continuous cutouts can also be provided, in which case in some embodiments (alternatively or additionally) continuous cutouts can also be provided. A non-continuous recess is to be understood as meaning a recess which, starting from the outside of the head element, is a blind hole or a Blind hole is formed. A continuous recess is to be understood, for example, as meaning that the corresponding recess has an unclosed passage between the outside of the head element and a surface of the anchor element. An important advantage of such a non-continuous recess is that a tool inserted into the recess does not lead to any expansion of the anchor element corresponding to the width of the tool. It can thus be prevented that the anchor element expands practically like a dowel and possibly damages the surrounding hard tissue. In addition, the closed end of the recess offers a starting point for a tool in order to be able to exert precisely defined pressure on the anchor element.

It is also particularly preferred if at least one contact structure is formed on an inner side of the head element, which is a surface of the head element facing the anchor element, which protrudes from the inner side of the head element in a direction essentially parallel to the longitudinal axis of the anchor element . In contrast to solutions known from the prior art, which often have sharp corner edges in the sense of simple thumbtack-like constructions exactly where the force of the fastening device ends on the tissue to be implanted, the contact structures can be used to achieve a defined and therefore more atraumatic force distribution and thus fixation of the tissue fragment or implant to the hard tissue can be achieved. The various properties and advantages of these contact structures will also be explained in more detail below.

The implant/tissue fragment to be attached to the hard tissue can have or consist of classic implant materials, soft implant materials and/or endogenous tissue structures. The classic implant materials include, for example, titanium, PEEK (polyetheretherketone), or other metals and polymers. Soft implants can include, for example, collagen membranes, hydrogels, extracellular matrix membranes (ECM membranes), and/or synthetic peptide membranes. Endogenous (patient's own) tissue structures can be endogenous hard tissue structures and/or endogenous soft tissue structures.

• - die Außenseite des Kopfelements, welche, wenn die Befestigungsvorrichtung gemeinsam mit dem Implantat oder Gewebefragment an dem Hartgewebe befestigt ist, an einer Außenfläche des Systems aus Befestigungsvorrichtung, Implantat/Gewebefragment und Hartgewebe, angeordnet ist,
• - die Innenseite des Kopfelements, welche, wenn die Befestigungsvorrichtung zusammen mit dem Implantat oder Gewebefragment an dem Hartgewebe befestigt ist, in Kontakt mit dem Implantat/Gewebefragment steht, und
• - eine Außenfläche (oder: Mantelfläche) des Ankerelements, welche, wenn die Befestigungsvorrichtung mit dem Implantat/Gewebefragment an dem Hartgewebe befestigt ist, in Kontakt mit dem Hartgewebe steht, insbesondere zum Teil, vorzugsweise jedoch nicht vollständig, in das Hartgewebe hinein eingeführt ist.

A further preferred embodiment or further development of the fastening device includes surface modifications and/or surface coatings of one, several or all of the relevant functional surfaces of the fastening device. A surface modification is to be understood in particular as meaning a structural change in a base material of the functional surface, such as processing the functional surface for roughening, for forming a thread or the like. Functional surfaces are in particular:

• - the outside of the head element, which, when the fastening device is attached to the hard tissue together with the implant or tissue fragment, is arranged on an outer surface of the system made up of the fastening device, implant/tissue fragment and hard tissue,
• - the inside of the head element, which when the fixation device is fixed to the hard tissue together with the implant or tissue fragment, is in contact with the implant/tissue fragment, and
• - An outer surface (or: lateral surface) of the anchor element, which, when the fastening device with the implant/tissue fragment is attached to the hard tissue, is in contact with the hard tissue, in particular partially, but preferably not completely, is inserted into the hard tissue.

Surface modifications and/or surface coatings, in particular of these functional surfaces, which can also be designed differently in each case, contribute significantly to the robustness and fixing strength of the fastening device; they may also allow the temporal change (e.g. resorption and/or biodegradation) of the fastener to be selectively influenced at different parts of the fastener and may also contribute to the atraumatic attachment of the fastener. Possible variants of the surface modifications and/or surface coatings of the various functional surfaces will also be explained in more detail below.

According to a second aspect, the invention provides a system for fastening an implant or a tissue fragment, comprising a fastening device according to an embodiment of the first aspect of the present invention and a tool for fastening this fastening device to the hard tissue (e.g. bone). The tool has a functional structure that can be inserted into at least one recess of the at least one recess of the fastening device. In other words, at least one of the recesses of the fastening device, if there are several recesses, or the only recess if there is only one of them, is advantageously designed in such a way that the functional structure of the tool can be inserted therein. This enables a particularly precise and atraumatic application of pressure during the attachment of the attachment device to the hard tissue, in particular during the insertion of the anchor element into the hard tissue. In other words, a pressure exerted on the functional structure of the tool can be transferred practically with pinpoint accuracy to specifically the anchor element. In particular in combination with contact structures formed on the inside of the head element, a potentially traumatic effect of the edge regions of the head element during the attachment of the fastening device to the hard tissue is thus significantly reduced.

Advantageous and preferred embodiments, variants or developments of embodiments are explained in more detail in the dependent claims and in the following description, in particular with reference to the figures.

According to some preferred embodiments, variants or developments of embodiments, the at least one recess is designed in such a way that it has a holding structure for a tool for fastening the fastening device to the hard tissue. The holding structure can in particular be designed such that a cross section of the recess, in the direction of the longitudinal axis of the anchor element in the direction from the head element to the anchor element, first tapers in at least one region, then widens and then tapers again. This structure of taper (first taper sub-zone) -> widening (broadening sub-zone) -> taper (second taper sub-zone) can start directly on the outside of the header, but can also be located further down along the recess. In addition, the first taper sub-zone in particular can also be multi-stage, i.e. first one type of taper is carried out according to a first geometric rule and then a second type of taper according to a second geometric rule, with the rate of taper in particular being second taper can be greater than the first taper.

In particular, the production of the fastening device entirely or partially from biodegradable base materials, in particular polymers or metals, can enable a temporally defined fastening. This means that the fastening device can be designed in such a way that it mechanically holds the implant/tissue fragment for a defined period of time, but then releases this fixation. Different components, such as the head element and anchor element or also individual areas of the head element and/or anchor element, can biodegrade at different rates in order to be able to implement desired, defined temporal fixation courses. For example, it can be brought about that the fastening device is only active in an inflammatory phase and prevents repositioning of the implant/tissue fragment during this period. After that, however, endogenous regeneration processes can spatially reposition the natural tissue in a biologically optimal manner.

In particular, the first tapering partial zone can cause the tool for fastening the fastening device with a functional structure to be easily inserted into the recess on the one hand, and that the functional structure is then increasingly guided to the desired force application point in the tip of the recess due to the tapering. For this purpose it is particularly advantageous if the second tapering sub-zone ends in the tip, i.e. in the end, of the recess.

In connection with embodiments of the second aspect of the present invention, it is advantageous if the functional structure of the tool has a barb structure with which the tool can be hooked in the region of widening (i.e. in the widening section) between the two partial tapering zones, around to be able to transport the fastening structure on the tool without risk of falling.

The functional structure of the tool and the holding structure can be coordinated with one another in such a way that the holding structure exerts such a low holding force on the functional structure of the tool that a holding force with which the fastening device is held on the hard tissue exceeds the holding force which the holding structure exerts on the functional structure of the tool exerts exceeds, in particular exceeds by a multiple. In this way, the fastening device can be easily transported using the tool and, at the same time, the tool can be easily removed again after the fastening device has been fastened to the hard tissue, without the fastening device being released from the hard tissue as a result.

According to some preferred embodiments, variants or developments of embodiments, at least one contact structure is formed on an inner side of the head element, which is a surface of the head element that faces the anchor element. The contact structure is preferably designed such that it protrudes from the inside of the head element in a direction essentially parallel to the longitudinal axis of the anchor element. In other words, the contact structure is advantageously made in this way formed that when the fastening device is attached to the hard tissue and the inside of the head element rests against a surface of the implant/tissue fragment, the contact structure bulges or bulges deeper into the implant/tissue fragment without tearing and non-destructively than the inside of the head element itself.

The at least one contact structure is arranged in particular at the edge, i.e. if possible at a lateral, i.e. lateral, end of the inside of the head element. Proceeding from a longitudinal axis of the anchor element, the lateral end can also be referred to as a radial end, i.e. one remote from the longitudinal axis. For example, the contact structure can form a wall structure running along the outer edge of the inside of the head element on the inside, which can be formed topologically, for example, as a closed ring or as a ring with one or more interruptions. In its cross section, the rampart structure can be rounded or tapered to a point, with the exact shape being able to be adapted to the properties of the implant/tissue fragment to be implanted.

For particularly soft implants/tissue fragments, the wall structure can be rounded at the point furthest from the inside of the head element (“contact point”), it being particularly advantageous to avoid any sharp edges in contact with the implant/tissue fragment. For example, in the case of more robust implants/tissue structures, at least one contact structure can be provided on the fastening device, which tapers to a point furthest from the inside of the head element (“contact point”), which, for example, in combination with the anchor element, improves the fixation of the implant/tissue fragment can also be accomplished in the radial direction to the anchor element. The radial direction with respect to the anchor element can also be referred to as the X/Y direction, namely when a coordinate system is laid out such that the Z direction is placed along the axial (or longitudinal) direction of the anchor element and X and Y axes thereto be arranged vertically in order to span a plane in which the head element is arranged substantially.

The at least one contact structure can in particular be rounded and/or tapered. In this context, “and/or” should be understood to mean that either a plurality of contact structures are provided, of which at least one is rounded and at least one is tapered, or it can be understood that one and the same contact structure, for example a wall structure, is located at one point is rounded and tapered at another point, for example with a smooth transition between these two points. For example, a transition of an implant/tissue fragment from (rather) soft to (rather) hard can be optimally accompanied.

Here, rounded contact structures can serve as a cushioning mechanism, i.e. to mitigate an effect of the edge region of the fastening device on the implant/tissue fragment. Pointed contact structures, on the other hand, can function in particular as an additional anchoring mechanism. Other possible configurations of the contact structures are also conceivable, for example a configuration as a spring element.

A site-specific immigration of cells can also be made possible by the specific spatial configuration at the edge. Further possible variants and options for the contact structure will be explained in more detail below with reference to the figures. For example, different areas at the edges of the head element and/or different contact structures can be designed to be biodegradable differently (i.e. differentially), for example via their volume/surface ratio.

According to some preferred embodiments, variants or developments of embodiments, the head element and/or the anchor element have a surface coating and/or a surface modification. The head element and/or the anchor element can have different surface coatings and/or surface modifications. In addition, the head element can be coated or modified on its inside and/or its outside, in which case the surface coatings/surface modifications on the inside and outside can be different from one another. Each functional surface (inside of the head element, outside of the head element, outer surface of the anchor element) can have one or more surface coatings/surface modifications. At least one surface coating/surface modification of the head element can differ from at least one surface coating/surface modification of the anchor element.

Different surface coatings of the anchor element and head element also enable a controlled and differentiated degradation behavior of the anchor element and head element, each individually. A surface coating that degrades slowly can thus retard the degradation of a more rapidly degrading underlying base material. This can be achieved, for example, that the base material (e.g. of the anchor element) persists for a long time (as long as the surface coating is still present) and then quickly degrades (if the surface coating itself is degraded).

The anchor element and the head element are preferably formed from the same base material, whereby, as already mentioned, they can differ from one another at least in places in a respective possible coating. The anchor element and the head element are particularly preferably designed in one piece in their basic structure (i.e. apart from a possible coating and/or surface modification). Anchor element and/or head element can either consist of biodegradable base material and/or non-degradable base material. Metals, ceramics, polymers, biocomposites or bioglasses are preferred for the biodegradable base materials. Titanium, PEEK, HDPE, UAMWPE, BP, and medical stainless steel are preferred for non-degradable base materials.

A possible surface modification of the anchor element can be designed in such a way that the anchor element has a smooth area and/or a rough, corrugated and/or thread-like area on its outer surface. The smooth portion is preferably located adjacent to the head member and the rough, knurled and/or threaded portion is preferably located adjacent to a tip (an end of the anchor member furthest from the head member).

A boundary (or: a transition) between the two regions may be provided essentially where, when the fastener is attached to the hard tissue, the hard tissue abuts the implant/tissue fragment. In other words, it can be provided that in the area of the implant/tissue fragment the outer surface of the anchor element is smooth and in the area of the hard tissue the outer surface of the anchor element is rough, corrugated and/or surface-modified like a thread. In this way, a holding force of the anchor element in the hard tissue can be improved without increased frictional forces acting on the implant/tissue fragment in the area of the anchor element or even a kind of rasp effect occurring.

The anchor element can have a surface coating which allows the anchor element to be introduced into the hard tissue without great mechanical effort. It is also preferred that the anchor element has a polymeric surface coating, which is designed in such a way that it swells in order to realize a fixation by means of a frictional connection to the surrounding hard tissue.

Particularly preferred is the surface coating of the anchor element at least partially (or completely) with a swelling bioresorbable fixation material.

The degradation behavior of the anchor element and/or head element can also be reduced by different coatings of biodegradable polymers, such as from the polyester group, such as PCL (polycaprolactone), PDLLA (poly-D,L-lactic acid), PLGA (polylactide co-glycolide), PGA (polyglycolic acid), and PLLA (polymer of L-(+)-lactic acid) or composite variants with calcium-based ceramic particles. It would also be conceivable to use purely biodegradable polymers from the group of polyurethanes and their biocomposites.

According to some preferred embodiments, variants or developments of embodiments, the anchor element is at least partially coated with a swelling, preferably bioresorbable, fixation material, the fixation material in particular having a polymer or consisting of one or more polymers.

According to some preferred embodiments, variants or developments of embodiments, the head element has a curvature tending in the direction of the anchor element. This should be understood to mean (qualitatively, not quantitatively) a curvature such as that of the fabric of an umbrella towards the handle of the umbrella. Such a curvature can cause the marginal areas of the head element to gently exert holding pressure on the implant/tissue fragment and, in particular, interact very well with contact structures formed on the marginal areas of the head element. The head element can thus exert a clamping effect on the implant/tissue fragment in its marginal areas, with the contact structure or contact structures realizing a pressure distribution in the marginal areas that is adapted to the implant/tissue fragment.

Distances from a lateral edge point of the head element to the center point of the head element and/or to a position of an anchor element can be designed differently within a fastening device, ie vary within a fastening device. A radius of curvature (or multiple radii of curvature for varying radii of curvature within a fastener or head member) can be adapted to an implant or tissue fragment to be fixed. In this way, individual size and materials can be taken into account.

According to some preferred embodiments, variants or developments of embodiments, a maximum diameter of the head element with respect to a length of the anchor element is in a ratio of at least 1:1, preferably at least 2:1, particularly preferably at least 3:1. A particularly large-area design of the head element enables good distribution of the holding pressure which the head element exerts on the implant/tissue fragment, and also enables large (wide) implants/tissue fragments to be fastened. For this purpose, contact structures can advantageously also be arranged in the middle of the inside of the head element.

• Ausbilden eines länglichen Ankerelements, welches entlang seiner Längsachse zum Fixieren der Befestigungsvorrichtung an dem Hartgewebe in das Hartgewebe einführbar ist; und
• Ausbilden eines flächigen Kopfelements, welches an einem Ende des Ankerelements auskragt;
• wobei sich mindestens eine nicht-durchgehende Ausnehmung von einer Außenseite des Kopfelements, welche eine von dem Ankerelement abgewandte Oberfläche des Kopfelements ist, ausgehend in das Ankerelement hinein erstreckt.

According to a third aspect, the present invention provides a manufacturing method for a fastening device for implants or tissue fragments on a hard tissue, comprising at least the steps:

• Forming an elongate anchor element which can be inserted into the hard tissue along its longitudinal axis in order to fix the fastening device to the hard tissue; and
• Forming a flat head element which cantilevers at one end of the anchor element;
• wherein at least one non-continuous recess extends from an outer side of the head element, which is a surface of the head element remote from the anchor element, into the anchor element.

The manufacturing method advantageously also includes further steps such as modifying a surface (particularly functional surface) and/or coating a surface (particularly functional surface) of the anchor element and/or head element, each preferably as described above and/or below.

• Bereitstellen eines Systems gemäß einer Ausführungsform des zweiten Aspekts der vorliegenden Erfindung;
• Ansetzen eines Implantats oder Gewebefragments an einem Hartgewebe eines Patienten;
• Ansetzen der Befestigungsvorrichtung an dem Implantat oder Gewebefragment;
• Einführen einer Funktionsstruktur des Werkzeugs in eine Ausnehmung der Befestigungsvorrichtung;
• Applizieren von Druck auf die Befestigungsvorrichtung mittels der Funktionsstruktur des Werkzeugs in der Ausnehmung, um das Ankerelement in das Hartgewebe einzuführen.

According to a fourth aspect, the invention also provides a treatment method, comprising at least the steps:

• providing a system according to an embodiment of the second aspect of the present invention;
• attaching an implant or tissue fragment to hard tissue of a patient;
• attaching the fixation device to the implant or tissue fragment;
• Inserting a functional structure of the tool into a recess of the fastening device;
• Applying pressure to the fastening device using the functional structure of the tool in the recess in order to introduce the anchor element into the hard tissue.

It can be provided that the fastening device is attached to the implant or tissue fragment that is already attached to the hard tissue, and that the functional structure of the tool is then inserted into the recess. Alternatively, it can also be provided, in particular if the recess has a holding structure, that the functional structure of the tool is introduced beforehand and the fastening device, in particular held on the functional structure of the tool by means of the holding structure, is brought to the implant/tissue fragment or carried. The fastening device can then also be attached to the implant/tissue fragment by means of the functional structure of the tool, which is also inserted into the recess. Some exemplary embodiments are explained in detail below with reference to associated figures. It goes without saying that the elements explained with reference to the various exemplary embodiments and the various figures can also be combined with one another or exchanged. In this way, a fastening device that is precisely adapted depending on the planned place of use, the planned type of implant/tissue fragment and the like can be provided.

character list

• 1 eine schematische Querschnittsdarstellung durch eine an einem Hartgewebe befestigte Befestigungsvorrichtung gemäß einer Ausführungsform der vorliegenden Erfindung;
• 2 eine schematische Querschnittsansicht einer Befestigungsvorrichtung gemäß einer weiteren Ausführungsform der vorliegenden Erfindung;
• 3 eine schematische Querschnittsansicht einer Befestigungsvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung;
• 4 verschiedene mögliche räumliche Ausgestaltungen eines Kopfelements einer erfindungsgemäßen Befestigungsvorrichtung;
• 5 eine schematische Querschnittsansicht durch eine Befestigungsvorrichtung gemäß noch einer weiteren Ausführungsform der vorliegenden Erfindung; und
• 6 eine schematische Darstellung eines Systems gemäß einer Ausführungsform des zweiten Aspekts der vorliegenden Erfindung.

The invention is explained in more detail below using exemplary embodiments in the figures of the drawings. The following are shown in a partially schematic representation:

• 1 a schematic cross-sectional representation through a fastening device fastened to a hard tissue according to an embodiment of the present invention;
• 2 a schematic cross-sectional view of a fastening device according to a further embodiment of the present invention;
• 3 12 is a schematic cross-sectional view of a fastening device according to yet another embodiment of the present invention;
• 4 various possible spatial configurations of a head element of a fastening device according to the invention;
• 5 a schematic cross-sectional view through a fastening device according to yet another embodiment of the present invention; and
• 6 a schematic representation of a system according to an embodiment of the second aspect of the present invention.

In all figures, elements and devices that are the same or have the same function have been provided with the same reference symbols unless otherwise stated.

Detailed description of the figures

1 12 shows a schematic cross-sectional view of a fastening device 100 according to an embodiment of the present invention. The fastening device 100 serves to fasten an implant/tissue fragment to a hard tissue 1, for example a bone of a mammal, in particular a human. 1 1 shows an implant membrane 2 as an example of an implant/tissue fragment, it being understood that other implants and/or tissue fragments, for example as already described in detail above, can also be attached to the hard tissue 1 by means of the attachment device 100.

In 1 the situation is also shown by way of example in which the implant membrane 2 is arranged in the final state between the hard tissue 1 and a surrounding tissue 3, for example the skin of the mammal or human. This surrounding tissue 3 thus also covers the fastening device 100 in the final state. It goes without saying, however, that in certain configurations it can also be provided that the fastening device 100 is arranged on an outside, ie it is accessible to the outside. In the following, the implant membrane 2 is frequently named as a representative for the implant/tissue fragment, and a human patient is named for the recipient of the implant, this being done in each case for the purpose of illustration and without restricting the generality.

In 1 it can be seen that the fastening device 100 can be roughly divided into a head element 110 on the one hand and an anchor element 120 on the other hand. The anchor element 120 is elongate, ie with a defined and in 1 immediately apparent longitudinal axis A. The anchor element 120 can be configured substantially rotationally symmetrically about this longitudinal axis A, but can also be configured mirror-symmetrically according to a plane running through the longitudinal axis A or be configured asymmetrically. “Essentially symmetrical” is intended to mean in particular that the basic structure of the anchor element 120 is symmetrical, with accidental local changes due to any surface coatings and/or surface modifications of an outer surface 121 of the anchor element 120 not being taken into account.

The anchor element 120 is designed to be inserted into the hard tissue 1 along its longitudinal axis A in order to fix the fastening device 100 to the hard tissue 1 such that, as in FIG 1 as can be seen, in the final state the anchor element 120 is largely, but preferably not completely, accommodated within the hard tissue 1 . In this sense, the hard tissue 1 can also be referred to as receiving tissue, since it at least partially receives the anchor element 120 .

The anchor element 120 is, as in 1 also shown, is roughly conical in shape overall, with a base of this cone being connected to the head element 110 and a tip of this cone element forming the part of the fastening device 100 that penetrates the hard tissue 1 the furthest.

A lateral surface 121 of the anchor element 120, in this case a conical lateral surface, can advantageously have a surface modification and/or a surface coating 127. At the in 1 illustrated embodiment, the surface modification and/or surface coating 127 extends from the tip of the cone of the anchor element 120 in the direction of the head element 110, with a transition to a smooth area 126 of the lateral surface 121 taking place at a point 125 of the lateral surface 121.

The surface coating and/or surface modification 127 can in particular be designed in such a way that it facilitates or improves the introduction and/or fixation of the anchor element 120 into the hard tissue 1 or in the hard tissue 1 . For example, a surface coating can be provided by a swelling bioresorbable fixation material, for example a polymer. Since this is used in particular for interaction with the hard tissue 1, the smooth region 126 of the lateral surface 121 can be formed on the head element-side end of the anchor element 120, so that interaction with the implant membrane 2 is minimized at this point. The transition area 125 can be placed in such a way that it lies within an area in which the implant membrane 2 will later be arranged, at the planned interface between hard tissue 1 and implant membrane 2, or within the hard tissue 1.

In 1 a surface design of the roughened area 127 of the lateral surface 121 of the anchor element 120 is preferably effected by corrugation, a thread structure and/or roughening. All of these variants increase the adhesion between anchor element 120 and hard tissue 1.

The head element 110 is arranged on the base of the conical anchor element 120 and can, for example, also be arranged and configured rotationally symmetrically about the longitudinal axis A of the anchor element 120 . The following are also, in particular with reference to 4 , variants are described in which this is not the case. The head element 110 is flat and has a curvature towards the anchor element 120 or towards the hard tissue 1 when the fastening device 100 is fastened to the hard tissue 1 . This curvature can increase a clamping effect which the head element 110 exerts on the implant membrane 2 .

The head element 110 has a flat inner side 112, which faces the anchor element 120 or which, if the fastening device 100 is fastened to the hard tissue 1, faces the hard tissue 1 and which therefore, when the fastening device 100 is used as intended (at least partially, or completely) is in contact with the transplant membrane 2. The head element 110 also has a flat outer side 111 which faces away from the anchor element 120 or from the hard tissue 1 when the fastening device 100 is used as intended and is either exposed or covered by the surrounding tissue 3 when used as intended.

The head element 110 advantageously has at least one contact structure 141, 142 on its inner side 112, which protrudes from the inner side 112 in a direction essentially parallel to the longitudinal axis A of the anchor element 120. These contact structures 141, 142 thus represent particularly relevant interaction points of the head element 110 and the fastening device 100 as a whole with the transplant membrane 2, since these will usually exert particularly strong pressure on the transplant membrane 2 due to their protrusion depending on a bending strength of the head element 110.

In 1 is shown how two contact structures 141, 142 are arranged on the inside 112 of the head element 110, each at a marginal, ie lateral, end of the head element 110. In this and in all other described embodiments, however, it can also be provided that a or several further contact structures are also arranged centrally in the surface of the inner side 112 of the head element 110.

Based on 1 two different contact structures 141, 142 are shown and explained. The contact structure 141 on the left-hand side is designed with a rounded cross section and can therefore, for example, fulfill a cushioning function or function as a cushioning mechanism. Such a cushioning mechanism prevents sharp edges from impacting the implant/tissue fragment 2 with increased pressure, as a result of which it could possibly be damaged. The contact structure 141 in 1 may be hemispherical, or may be a wall with a rounded or semi-circular cross-section that completely or partially surrounds the edge of the inner side 112 of the head element 110 .

In contrast, the contact structure 142 on the right side of 1 has a pointed shape and can thus fulfill an anchor function or act as an anchor mechanism. In particular, several contact structures 142 can be arranged, which contribute to the additional fixing of the fastening device 100 to the hard tissue 1 in the X/Y direction. Such contact structures 142 with an anchoring mechanism can preferably be provided in plurality and arranged approximately at regular intervals along the edge of the inner side 112 of the head element 110 in order to bring about a homogeneous lateral fixation (ie in the XY plane) of the implant/tissue fragment 2 or to reinforce.

In 1 For the sake of simplicity, it is shown that one and the same fastening device 100 has both the contact structure 141 with a cushioning function and the contact structure 142 with an anchoring function, and both act on the same implant/tissue fragment 2 . It goes without saying that further contact structures can also be provided. However, it is also understood that the fastening device 100 can also be designed with only contact structures 141 with a cushioning function, only with contact structures 142 with an anchoring function, or with a large number of contact structures 141 with a cushioning function and/or contact structures 142 with an anchoring function.

The fastening device 100 can in particular be designed in such a way that, for example in the case of inhomogeneous implants/tissue fragments, which for example have firmer and softer substructures, different contact structures 141, 142 act on different substructures with different properties, depending on whether an anchor function or a cushioning function is sought . In addition to the contact structures 141, 142 with a cushioning function and anchoring function, further types of contact structures can also be provided, for example contact structures which are designed as spring elements. The head element 110 preferably also has a certain flexibility, so that in combination with the properties of the contact structures 141, 142, a force and pressure distribution that is precisely adapted to the hard tissue 1 and/or the implant/tissue fragment 2 can be achieved.

The contact structures 141, 142 can either consist of the same material as a main body of the head element 110 itself, in which case the head element 110 and the contact structures 141, 142 can in particular be designed in one piece. Alternatively or additionally, some or all of the contact structures 141, 142 can also be formed by a surface modification or surface coating, for example a polymeric coating. In this way it is possible, for example, to standardize the basic shape of the head element 110 and, by means of a targeted polymeric coating, to provide contact structures with any desired shape specifically at positions on the inside 112 of the head element 110 that are adapted to a specific implant/tissue fragment 2 or a specific patient . The manufacturing method according to the invention can include corresponding method steps, such as: detecting an anatomy of a patient; and coating, in particular with a polymeric coating, the inside 112 of the head element 110 with at least one contact structure based on the recorded anatomy of the patient. The fastening device 100 also has at least one non-continuous recess 130 which, starting from an opening 131 on an outer side 111 of the head element 110 , extends into the anchor element 120 . The outside 111 of the head element 110 is a surface of the head element that faces away from the anchor element 120 and from the inside 112 of the head element 110 . It is understood that if several anchor elements 120 are attached to one and the same head element 110 of the fastening device 100, each anchor element 120 can also be provided with a recess 130 and even each anchor element 120 can be provided with a non-continuous recess 130. "Non-continuous" in this context means in particular, as in 1 shown that the recess 130 has only a single opening, namely the opening 131 in the outside 111 in the head element 110 .

The recess 130 can be embodied symmetrically, for example with respect to the longitudinal axis A of the anchor element 120, in particular rotationally symmetrically or mirror-symmetrically with respect to a plane through the longitudinal axis A, or it can be embodied asymmetrically. All variants are possible, regardless of whether the anchor element 120 is designed symmetrically or asymmetrically. In the present exemplary embodiment, the recess 130 is likewise cut out in the form of a cone from the interior of the cone which represents the anchor element 120 , the base of the cone being attached to the outside 111 of the head element 110 .

As has already been described in more detail above, the recess 130 serves in particular to accommodate a tool, more precisely: a functional structure of a tool, through which the fastening device 100 is applied precisely and with precise pressure placement and pressure metering along the anchor element 120 in the hard tissue 1 can be introduced. If the fastening device 100 is made of a flexible material overall, the recess 130 can also assume a certain buffering function in that the opening 131 can be slightly compressed or stretched, so that the fastening device 100 can adapt to deformations or movements of the implant/tissue fragment 2.

The extensions and dimensions of the head element 110 and the anchor element 120 are in FIG 1 not drawn to scale to simplify description. In fact, however, it is preferred that a maximum diameter d2 of the head element 110 (in a projection of the head element 110 onto the XY plane) is at least as large and more preferably is greater than a length L of the anchor element 120. Although this is not the case here as shown, a ratio of d2 to L of at least 1:1, more preferably 2:1, especially at least 3:1 is preferred. Particularly in combination with the marginal contact structures 141, 142, a holding force can thus be exerted by the fastening device 100 over a large surface of the implant/tissue fragment 2, while at the same time the intervention that the fastening device 100 carries out on the hard tissue 1 is minimized. In order to achieve the necessary holding force by the anchor element 120 on the hard tissue 1, this can preferably be provided with surface coatings and/or surface modifications, as already described, in order to improve the fixation between the anchor element 120 and hard tissue 1.

A diameter d1 of the opening 131 preferably assumes values between 2 mm and 25 mm (more preferably between 5 mm and 20 mm, even more preferably between 10 and 15 mm) and/or is between 3 and 20 percent of the diameter d2 of the head element 110 (or .of the respective head element in which the opening 131 is formed det), preferably between 5 and 15 percent, more preferably between 7 and 12 percent.

2 shows a schematic cross-sectional illustration through a fastening device 200 according to a further embodiment of the present invention. The fastening device 200 is a variant of the fastening device 100 from FIG 1 and differs from this in the design of its head element 210 and the design of its anchor element 220. In the case of the head element 210 of the fastening device 200, contact structures 141 with a cushioning mechanism are arranged on both sides of the illustrated cross section, each of which has a surface coating or modification, e.g. a site-specific micro- /nanotopography or a hybrid surface modification (plasma process). This causes an even gentler contacting of the implant/tissue fragment (in 2 not shown) by the fastening device 200.

The anchor element 220 of the fastening device 200 has, in contrast to 1 illustrated anchor element 120 of the fastening device 100, a polymeric anchor element coating 227, which comprises the entire lateral surface 121 of the anchor element 220 in the illustrated embodiment. This coating can, for example, in turn be or have a swelling, bioresorbable fixation material.

Further options for fixation, which can be used with each of the fastening devices presented here, consist, for example, in the use of marginal liquefaction, after introduction of the fastening device 200 into the hard tissue 1, of a polymer on the lateral surface 121 of the anchor element 220 by energy input, for example ultrasound . In this way, the anchor element 220 can practically fuse with the hard tissue 1 . (In particular soft) surface coatings made of polymeric materials can serve as a basis for a surface coating 227 of the anchor element 220, which can allow the anchor element to be introduced into the hard tissue 1 without great mechanical effort, while the head element 210 holds the implant/tissue fragment 2 to be fixed locked.

3 shows a schematic cross-sectional illustration through a fastening device 300 according to yet another embodiment of the present invention. For the 300 in 3 no recess 130 is shown, which can either be understood in such a way that this fastening device 300 has no recess 130 or in such a way that the 3 The cross-sectional view shown runs through an anchor element 320 which has no recess 130 , but the fastening device 300 can have further anchor elements 120 , at least one of which has a recess 130 .

3 serves primarily to illustrate the variants according to which an inner side 312 of a head element 310 of the fastening device 300 and/or an outer side 311 of the head element 310 of the fastening device 300 can have a surface coating. A surface coating 318 on the inside 312 can be designed such that, as in 3 shown by way of example, one or more contact structures 141 are not covered by the surface coating 318 . Alternatively, however, the surface coating 318 can also include the contact structures, or both a surface coating 318 on the inside 312 as in 3 shown as well as, additionally, a surface coating 247 specifically of the contact structures 141, as in 2 shown, be provided. A bioresorbable surface coating 247, 318 made from a resorbable hydrogel-like component, eg from collagen, fibrinogen or hyaluronic acid, would be advantageous here. However, variations made from resorbable polyester components and/or degradable polyurethanes would also be conceivable. The surface coating 247, 318 can be applied site-specifically within a post-processing step using a coating method. A specific degradation kinetics can be set by the way the application parameters are applied.

As already mentioned, a surface coating 227 of the anchor element 220 (see 2 ) and a coating of the inside and/or outside 311, 312 of the head element 310 (see 3 ) are coated with different polymers and/or biocomposites, which differ significantly from one another chemically and in their degradation behavior. This also enables a controlled and differentiated degradation behavior of head element 310 and anchor element 320 to be defined. Biodegradable polymers such as PCL, PDLLA, PLGA, PGA, PLLA or composite variants with calcium-based ceramic particles can be used for the coating.

4 shows a selection of different designs of head elements 410, 510, 610, 710 of fastening devices, which in turn can each be designed according to one of the preceding and/or following embodiments.

4 shows top views against the Z direction, i.e. from the direction of the surrounding tissue 3, of the respective fastening device and the implant/tissue fragment 2. A respective head element of a fastening device according to the invention can, for example, have hand-shaped or astrally arranged protuberances in the X/Y plane exhibit.

4a shows a head element 410 with an irregular star-like outline with a single recess 430 in the area of the geometric center of gravity of the head element 410, it being understood that the recess 430 is divided into a (in 4a not visible) anchor element protrudes. The corresponding anchor element fixes the fastening device with the head element 410 centrally on the hard tissue. With such star-shaped outlines of head elements 410 as in 4a or also in the following 4b it is particularly advantageous if a contact structure is formed in one, several or all points of the star-shaped outline on the respective inner side of the head element 410, in particular a contact structure with an anchor function.

4b also shows a possible shape for a head element 510 with a central recess 530, which has a star-shaped outline and wherein a contact structure is also advantageously arranged in each point of the star-shaped outline on the inside of the head element 510, in particular a contact structure with an anchor function.

4c shows schematically a head element 610 of a fastening device with a central recess 630. In this form of a head element 610, a contact structure can be formed on the inside of the head element 610, for example, circumferentially, either uninterrupted or in sections, or there can be point contact structures, e.g. with a cushioning function and/or Anchor function, be arranged along the edge of the inside of the head element 610.

4d shows another possible design of a head element 710, this time with two recesses 730-1, 730-2, whereby, for example, a better fixation of the corresponding fastening device can be achieved.

5 shows a schematic cross-sectional illustration through a further fastening device 800 according to yet another embodiment of the present invention.

Fastening device 800 is a variant of fastening device 200 from FIG 2 and differs from it on the one hand in that the contact structures 141 do not have a coating (although this is of course possible), on the other hand primarily in the design of the recess 830 in the head element 810 of the fastening device 800.

The anchor element 820 has a surface coating 827, which can be configured, for example, as described above with reference to the surface coating 227 of the anchor element 220 of the fastening device 200.

The recess 830 is only accessible through an opening 831 in an outer side 811 of the head element 810 . The basic structure of the recess 830 is the same as that of the recess 130 of the fastening device 100 or the fastening device 200, except that the shape of the recess 830 is additionally added with a holding structure 835. This holding structure 835 is designed, for example, as a wall or bead that runs along the inner surface of the recess 830 and is arranged rotationally symmetrically with respect to the longitudinal axis A of the anchor element 820 . The holding structure 835 serves to accommodate a functional structure of a tool and can be adapted accordingly; for example, the holding structure 835 can also be designed and arranged mirror-symmetrically to a mirror plane that encompasses the longitudinal axis A of the anchor element 820 .

• Mit der Öffnung 831 beginnt zunächst eine erste Verjüngungs-Teilzone, welche wiederum zwei verschiedene Teilbereiche 832, 836 aufweist. In der ersten Verjüngungs-Teilzone verjüngt sich eine Querschnittsfläche (senkrecht zur Längsachse A) der Ausnehmung 830 stetig; im ersten Teilbereich 832 geschieht dies gemäß einer einfachen Kegelstumpfform, im zweiten Teilbereich 836 gemäß der Geometrie einer Hälfte eines Loches in einem Torus, welcher gemäß dem Winkel der Kegelstumpfform ausgestülpt wurde. Radien von Kegelstumpfform und Torus können jeweils an die gewünschte Anwendung und das gewünschte Werkzeug oder die gewünschte Funktionsstruktur des Werkzeugs angepasst werden.

Due to the arrangement of the holding structure 835, the recess 830 of the fastening device 800 advantageously has the following structure, described starting from the opening 831 in the direction of the tip of the recess 830 or in the direction of the tip of the anchor element 820:

• With the opening 831, a first tapering sub-zone begins, which in turn has two different sub-areas 832, 836. In the first tapering sub-zone, a cross-sectional area (perpendicular to the longitudinal axis A) of the recess 830 tapers steadily; in the first portion 832 this is done according to a simple truncated cone shape, in the second portion 836 according to the geometry of a half of a hole in a torus everted according to the angle of the truncated cone shape. Radii of the truncated cone shape and torus can each be adapted to the desired application and the desired tool or the desired functional structure of the tool.

The first tapering sub-zone 832, 836 is followed by a widening sub-zone 837, in which the cross-sectional area of the recess tion 830 widens again, in particular according to the geometry of the other half of the hole in the everted torus.

Immediately following the broadening sub-zone 837 is a second tapering sub-zone 838 which ends in the tip of the recess 830 . The second taper subzone 838 is formed in a cone shape. Since the holding structure 835 is preferably placed on the conical recess 830 in its basic shape, the lateral surface of the conical shape of the second tapered partial zone 838 is aligned with the lateral surface of the first partial region 832 of the first tapered partial zone. To put it another way, a virtual extension of the lateral surface of the cone shape of the second partial taper zone 838 would encompass the lateral surface of the first partial area 832 of the first partial taper zone.

As has already been described above, and on the basis of 5 is immediately apparent, a functional structure of a tool, which has a barb structure (or: projection, or: thickening), can be inserted into the recess 830 in such a way that the barb structure hooks in the area of the broadening partial zone 837 and the second narrowing partial zone 838 . A certain holding force is thus exerted on the functional structure of the tool by the holding structure 835, for example in order to be able to transport the fastening device 800 on the functional structure or the like.

6 10 shows a schematic representation of a system 1000 according to an embodiment of the second aspect of the present invention using the example of the fastening device 800 5 . In addition to the fastening device 800, the exemplary system 1000 also includes a tool 10, which has a functional structure 11, which can be inserted into the recess 830 of the fastening device 800 in such a way that a tip 12 of the functional structure 11 of the tool 10 is at the tip of the recess 830 in order to be able to drive the fastening device 800 into the hard tissue 1.

The functional structure 11 of the tool 10 in 6 is thus advantageously specific to the recess 830 of the fastening device 800 5 adjusted so that the recess 830 can act as a receptacle for the functional structure 11 of the tool 10 . For this purpose, the functional structure 11 advantageously has a thickening 13 directly adjoining its tip 12, which in turn is adjoined by a narrowing 14. The thickened area 13 corresponds in length, width and shape to the second partial zone of tapering 838 at the tip of receptacle 830. The length of tapering 14 of functional structure 11 essentially corresponds at least to the combined length of the second partial area of the first partial zone of tapering 836 and the broadening partial zone 836, i.e. essentially the length of the holding structure 835 along the longitudinal axis A of the anchor element 820. In this way, the thickened portion 13 of the functional structure 11 can be inserted barb-like into the front area of the receptacle 830 and is held there by the holding structure 835 held back with a certain holding power. A handle for a human hand or a connecting element for a robot arm or the like can be arranged (not shown) at an end of the tool 10 opposite the tip 12 .

The material, shape and dimensions of holding structure 835 and functional structure 11 are advantageously designed such that the holding force of fastening device 800 after insertion of anchor element 820 into hard tissue 1 exceeds the holding force exerted by holding structure 835 on thickening 13. The fastening device 800 can thus be transported on the functional structure 11 of the tool and, after the fastening device 800 has been introduced into the hard tissue 1, can be easily removed from it again without the risk of the fastening device 800 slipping off the functional structure 11 in the meantime. Alternatively or additionally, functional structure 11 and holding structure 835 can also be designed such that by rotating functional structure 11 inserted into receptacle 830 about longitudinal axis A, functional structure 11 latches in holding structure 835 and can be unlocked again by further rotating and/or rotating back.

Although the present invention has been described above on the basis of preferred exemplary embodiments, it is not limited thereto but can be modified in a variety of ways. In particular, the invention can be changed or modified in many ways without departing from the essence of the invention.

Reference List

1

hard tissue (bone)

2

graft membrane

3

surrounding tissue

10

Tool

11

functional structure

12

Top

13

thickening

14

rejuvenation

100

fastening device

110

header element

111

outside of the header

112

inside of the header

120

anchor element

121

Outer surface of the anchor element

125

crossing

126

smooth area

127

Surface coating and/or surface modification

130

recess

131

opening

141

contact structure

142

contact structure

200

fastening device

210

header element

220

anchor element

227

surface coating

247

coating

300

fastening device

310

header element

311

outside

312

inside

317

surface coating

318

surface coating

410

header element

430

recess

510

header element

530

recess

610

header element

630

recess

710

header element

730-1

recess

730-2

recess

800

fastening device

810

header element

811

outside

820

anchor element

827

surface coating

830

recess

831

opening

832

first portion of the first taper sub-zone

835

holding structure

836

second portion of the first taper sub-zone

837

broadening subzone

838

second taper sub-zone

1000

system

A

Longitudinal axis of the anchor element

d1

diameter of the opening

d2

diameter of the head element

L

Length of the anchor element

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2017/089381 A1 [0005]

Claims (10)

Fastening device (100; 200; 300; 800) for implants or tissue fragments (2) on a hard tissue (1), having: an elongate anchor element (120; 220; 320; 820) which can be inserted into the hard tissue (1) along its longitudinal axis (A) for fixing the fastening device (100; 200; 300; 800) to the hard tissue (1); and a planar head element (110; 210; 310; 410; 510; 610; 710; 810) which cantilevers at one end of the anchor element (120; 220; 320; 820); wherein at least one non-continuous recess (130; 430; 530; 630; 730-1, 730-2; 830) extends from an outer side (111; 311; 811) of the head element (110; 210; 310; 410; 510; 610; 710; 810), which is a surface of the head element (110; 210; 310; 410; 510; 610; 710; 810) facing away from the anchor element (120; 220; 320; 820), proceeding into the anchor element (120 ; 220; 320; 820). Fastening device (800) after claim 1 , wherein the at least one recess (830) is designed in such a way that it has a holding structure (835) for a tool (10) for attaching the fastening device (800) to the hard tissue (1), in which holding structure (835) there is a cross section of the recess (830), in the direction of the longitudinal axis (A) of the anchor element (820) in the direction from the head element (810) to the anchor element (820), first tapers, then widens, and then tapers again. Fastening device (100; 200; 300; 800) according to one of the preceding claims, wherein on an inner side (112; 312) of the head element (110; 210; 310; 410; 510; 610; 710; 810), which one to the anchor element (120; 220; 320; 820) facing surface of the head element (110; 210; 310; 410; 510; 610; 710; 810), at least one contact structure (141, 142) is formed, which starting from the inside ( 112; 312) of the head member (110; 210; 310; 410; 510; 610; 710; 810) in a direction substantially parallel to the longitudinal axis (A) of the anchor member (120; 220; 320; 820). Fastening device (100; 200; 300; 800) according to claim 3 , wherein the at least one contact structure (141, 142) is rounded or tapered. Fastening device (200; 300; 800) according to one of the preceding claims, wherein the head element (210; 310; 810) and/or the anchor element (220; 320; 820) have a surface coating (227, 247; 317, 318; 827). . Fastening device (200) after claim 5 , wherein both the head element (210) and the anchor element (220) have at least one respective surface coating (227, 247) and wherein at least one surface coating (247) of the head element (210) differs from at least one surface coating (227) of the anchor element (220 ) differs. Fastening device (200; 800) after claim 5 or 6 , wherein the anchor element (220; 820) has a surface coating (227; 827) by means of a swelling, preferably bioresorbable, fixing material. Fastening device according to one of the preceding claims, in which the head element has a curvature tending in the direction of the anchor element. Fastening device (100; 200; 300; 800) according to one of the preceding claims, wherein a maximum diameter (d2) of the head element (110; 210; 310; 810) in relation to a length (L) of the anchor element (120; 220; 320; 820 ) in a ratio of at least 1:1, preferably at least 2:1, particularly preferably at least 3:1. System (1000) for fixing an implant or a tissue fragment (2), comprising: a fixing device (100; 200; 300; 800) according to any one of Claims 1 until 9 ; a tool (10) for attaching the attachment device to the hard tissue (1), which tool is inserted into at least one recess (130; 430; 530; 630; 730-1, 730-2; 830) of the at least one recess (130; 430; 530; 630; 730-1, 730-2; 830) has an insertable functional structure (11).

Images