Nerve conduit

Abstract

The present invention relates to the field of nerve conduits and the use and methods of using such nerve conduits to treat nerve injuries. In particular, the present invention relates to a nerve conduit that supports the repair of nerve injuries by facilitating proper insertion and / or fixation of nerve ends into the nerve conduit. A nerve conduit (10) is proposed comprising an elongate body (12) having a central portion (14) defining an internal cavity (16) and a plurality of end portions (18) defining respective openings (20) into the internal cavity (16) and disposed adjacent the central portion (14) at longitudinally opposed ends of the elongate body (12). According to the present invention, the cross-sectional area of ​​at least one opening (20) is greater than the cross-sectional area of ​​the internal cavity (16) of the central portion (14).

Description

[Technical field]

[0001] The present invention relates to nerve conduits and the use and methods of using such nerve conduits to treat nerve lesions. In particular, the present invention relates to nerve conduits that support the repair of nerve lesions by facilitating proper insertion and / or fixation of nerve ends into the nerve conduit. [Background technology]

[0002] When a person suffers trauma, one or more nerve damages in the peripheral nervous system may accompany tissue damage, which may result in partial sensory loss and / or impaired motor skills. Such traumas with nerve damage occur particularly in the upper limbs (e.g., the human hand or fingers). As a result, if the nerve damage is not properly treated, the person may suffer, for example, a loss in tactile or haptic feedback and / or have difficulty controlling fine motor skills in the trauma area.

[0003] Current treatments for nerve injuries include joining the nerve ends by various suturing techniques to provide a substantially tension-free connection between the respective nerve ends. In cases of more severe defects where the nerve ends are not directly adjacent to each other, reconstruction may be required to overcome the corresponding gap. Reconstruction may be performed, for example, by autologous or allogenic nerve grafts. Alternatively, reconstruction may be performed by providing tubular structures to provide a nerve guide. Such tubular structures may be provided, for example, by autologous or allogenic venous structures, or by artificially created nerve conduits made from biocompatible materials. The use of tubular structures may further facilitate the repair of the injury, regardless of the presence of a gap, for example, by providing additional mechanical support and structural stability, providing a tension-free repair, providing a guide for axonal growth limiting the risk of neuromas, reducing the inflammatory response to the site of the injury, and / or limiting the spread of fibrous tissue growth.

[0004] Tubular structures, particularly nerve conduits, are generally formed as substantially cylindrical shapes that extend longitudinally and define an internal lumen or through-hole from one end to the opposite end. The shape may be formed as an irregular cylindrical shape, e.g., with a cross-section resembling a star or snowflake shape, asymmetric cylindrical shape, or a shape with a substantially (rounded) rectangular cross-section. The dimensions and shape are selected to match the affected microstructure of the traumatic nerve tissue and surrounding tissue. To treat nerve injury, a nerve end is inserted into the nerve conduit through one end of the nerve conduit, and the corresponding other nerve end is inserted into the nerve conduit through the opposite end of the nerve conduit. The ends can then be fixed or joined to the nerve conduit, e.g., by suturing techniques or by applying or depositing a medical adhesive. In the implanted state, the nerve conduit forms a nerve guide. In this case, the continuous cylindrical shape of the nerve conduit and internal lumen provides a directional pathway for neurogenesis.

[0005] US2010 / 0016874 describes a double-walled toroidal sheath structure for use as a nerve conduit having a first and a second opening defined by a flexible connection between first and second inner and outer surfaces, respectively, that are capable of eversion and un-eversion with respect to one another. When a nerve end is placed in one opening of the structure, an external force is exerted on the conduit, and eversion and un-eversion of the inner and outer surfaces allows longitudinal roll shift of the sheath over the nerve. When the nerve end is placed in the first and second openings, successive sheath shifts effect their connection.

[0006] CN110236622 relates to a nerve conduit for making small gap (i.e. 2mm) sleeve connections and suturing nerves of various sizes.

[0007] US 3,833,002 describes a nerve conduit comprising a tube with an inner diameter slightly larger than the diameter of the nerve ends to allow for slidable insertion. Advantageously, the conduit is adapted to apply a vacuum to the interior of the tube to allow the nerve ends to be brought into direct contact or into close proximity to each other prior to application of a sealing material to the tube / nerve junction.

[0008] WO2012 / 133019 describes a sleeve body for nerve regeneration that does not require microsutures or sealing materials to keep the nerve ends in place. The sleeve body comprises separate arm pieces divided into sections via slits extending from the end sections of the body, and a clamping body. In use, the arm pieces are displaced from a position away from the periphery of the nerve to a position in contact with the periphery of the nerve by moving the clamping body to apply a radial force to the arm pieces. The ends of the nerve are wrapped and held securely without the need for suturing.

[0009] The elements of the present invention are described below. Although these elements are listed with specific embodiments, it should be understood that they can be combined in any manner and in any number to create additional embodiments. The various described examples and preferred embodiments should not be understood to limit the present invention to only the explicitly described embodiments. It should be understood that the present specification supports and encompasses embodiments in which any number of the disclosed and / or preferred elements are combined with the explicitly described embodiments. Furthermore, unless otherwise specified, any permutation and combination of all elements described in this application should be considered to be disclosed by the specification of this application.

[0010] Unless otherwise required, throughout this specification and the claims that follow, the term "comprise" and variations such as "comprises" and "comprising" are understood to imply the inclusion of the stated elements, integers, or steps, but not the exclusion of any other unstated elements, integers, or steps. The term "consist of" is a specific embodiment of the term "comprise", in which any other unstated elements, integers, or steps are excluded. In the context of the present invention, the term "comprise" encompasses the term "consist of". Thus, the term "comprising" encompasses "including" and "consisting". For example, the construction "comprising" of X may consist of X only, or may include something additional (e.g., X+Y).

[0011] The terms "a" and "an" and "The" and similar references used in the context of describing the present invention (particularly in the context of the claims) should be understood to include both the singular and the plural, unless otherwise specified herein or clearly contradicted by context. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of individually referring to each separate value falling within the range. Unless otherwise specified herein, each individual value is incorporated herein as if it were individually set forth herein. No term in this specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0012] The term "about" in reference to a number x means x±10%.

[0013] In numbers with decimal places, a comma (,") or a dot (".") are used interchangeably herein, i.e., throughout the specification and claims. Thus, numbers with decimal places can be represented by either a comma (,") or a dot ("."). For example, an exemplary value of "0.5" can also be represented as "0,5." This applies to other values ​​with decimal places as well. In particular, a comma (,") in a number indicates a decimal place, but is not used as a "thousands separator." Summary of the Invention

[0014] There is a need to depart from the known prior art to further facilitate repair of nerve damage.

[0015] According to the present invention, it is recognized that the continuous cylindrical shape and dimensional limitations of current nerve conduits make it difficult to insert nerve ends into the respective ends of the nerve conduit. The nerve ends are either pushed into the nerve conduit (risking nerve damage) or pulled into the nerve conduit using, for example, microsutures or vacuum (which can be cumbersome and harmful to the respective nerve ends). Furthermore, it has been found to be difficult to ensure that a predetermined amount of medical adhesive for fixing the nerve ends to the nerve guide is properly applied or deposited so that the respective nerve ends are properly contained within the guide. That is, the medical adhesive may not be applied uniformly around the respective nerve ends and / or an excess amount of medical adhesive may leak into the space between the respective nerve ends (which may impair nerve growth) or leak out of the conduit into the surrounding tissue (which may cause the nerve conduit to lose flexibility and / or cause adverse effects on the surrounding tissue).

[0016] It is therefore an object of the present invention to further facilitate repair of nerve injuries, in particular by ensuring proper insertion and fixation of each nerve end within and to the nerve conduit, without the need for microsutures or vacuum and / or with minimal damage to the underlying nerve.

[0017] The above objects are achieved by the independent claims. Preferred embodiments are set out in the dependent claims, the description and the drawings.

[0018] Thus, in a first aspect, a nerve conduit is proposed comprising an elongate body having a central portion defining an internal cavity and a plurality of end portions defining respective openings to said internal cavity and arranged adjacent to said central portion at longitudinally opposed ends of said elongate body, wherein according to the invention, the cross-sectional area of ​​at least one opening is greater than the cross-sectional area of ​​said internal cavity in said central portion.

[0019] By providing at least one end of the nerve conduit with a larger cross section, the insertion of the respective nerve ends of the nerves to be repaired is significantly facilitated. In particular, the larger cross section may provide a certain tolerance for (unintentional) offsets of the insertion height of the nerve ends relative to the cross section of the inner cavity of the central portion during the repair procedure. This ensures that, even if such offsets occur, the nerve ends are received in the nerve conduit and (slight) adjustments can be made without the need for reinsertion of the nerve ends or specific manipulation of the nerve conduit. In addition, the larger cross section further facilitates proper insertion of the respective nerve ends by acting as an optical guide surface for the surgeon. As a result, proper insertion and positioning of the nerve ends into the nerve conduit (e.g., into the inner cavity (which may be specifically dimensioned to accommodate the nerve ends to be connected)) may be achieved more easily and efficiently without adversely affecting the respective nerve ends.

[0020] At the same time, the nerve conduit may still be configured according to desired or predetermined dimensions and may provide a continuous guiding structure for neurogenesis. Modification of the central section is not necessary so that a certain structural stability and dimensioning of the nerve conduit may be achieved. However, the lumen or interior of the elongate body, i.e., the inner wall of the central section and / or end section(s), may comprise grooves, internal structures and / or holes. This may avoid possible pressure buildup or bubble formation inside the nerve conduit and / or improve the mechanical properties of the nerve conduit and / or promote nerve growth.

[0021] Furthermore, depending on the material used for the nerve conduit, a certain flexibility and / or resilience may be provided in at least the central portion so that the end portions do not (too much) affect the overall structural properties of the elongate body or the entire nerve conduit.

[0022] The larger cross-section may further aid in the application of the medical adhesive towards or outside the internal cavity. It may be particularly dimensioned to accommodate the nerve ends to be connected only through the corresponding openings, preferably into the respective openings. For example, the larger cross-section may prevent the medical adhesive from being inadvertently applied to the outer surface of the nerve conduit and / or into the internal cavity of the central portion. In addition, it may ensure that the medical adhesive faces the boundary between the openings and the internal cavity and / or that a significant amount of the medical adhesive does not leak out of the nerve conduit and / or into the internal cavity of the central portion when applying or inserting a given amount of medical adhesive. In particular, the larger cross-sectional area facilitates the application of the medical adhesive to the junction between the nerve and the nerve conduit, i.e., the junction between the inserted nerve end and the edge of the opening at the end portion of the opening that faces away from the central portion. The larger cross-section may also be provided to receive a certain amount of medical adhesive, for example, when application is improper, so that a predetermined amount of medical adhesive may be indicated to have been applied, or the occurrence of an application error during application of the medical adhesive is immediately apparent. In other words, the larger cross-section may also be configured to indicate that an excessive amount of medical adhesive has been applied, or that the medical adhesive has not been applied properly and application should be interrupted or stopped.

[0023] According to one preferred embodiment, (i) an interface between the medical adhesive and end portions extending from the central portion and having a larger cross-sectional area; and / or (ii) securing a medical adhesive onto end portions extending from the central portion and having a larger cross-sectional area; This is improved by having exterior structures with particular geometric shapes or irregular surfaces (such as holes, grooves or lines) on the outer surfaces of the end portions extending from the central portion.

[0024] The nerve conduit may have various sizes and shapes and may be configured to repair one or more nerve injuries. For example, directly adjacent nerves may be repaired by a single nerve conduit. In this case, the internal cavity and the opening may be provided with a separation wall, for example, so that two adjacent nerves may each be received in a separate compartment.

[0025] The elongate body may comprise multiple end portions, and / or the openings at the longitudinal ends of the elongate body may comprise multiple openings, e.g., two separate openings, at at least one of the multiple end portions, or may be configured as a single opening defining two separate compartments (or receiving portions) allowing for the insertion and accommodation of the respective nerve ends. Such an embodiment may have the advantage that only a single nerve conduit may be required for multiple nerve injuries and / or nerve extensions, facilitating the procedure for repairing the nerve injuries or connecting the respective nerve ends. The elongate body may, for example, have a Y-shape.

[0026] In some embodiments, the nerve conduit comprises only a single internal lumen, in particular a single internal cavity. For various applications, a single internal cavity is sufficient, which provides flexibility and allows simple manufacture and handling. The central portion is preferably formed as a substantially tubular shape. In other words, the central portion of the nerve conduit is a tube, such as a cylindrical tube, with a single internal cavity, which may preferably have substantially the same thickness (substantially the same internal diameter and substantially the same external diameter) along the entire length of the central portion. Preferably, the elongate body (of the nerve conduit) comprises two end portions, in particular one end portion at each end of the central portion (tube). The shape, dimensions, and / or material (and / or other characteristics) of the two end portions (of the same nerve conduit) may be substantially the same. The two end portions (of the same nerve conduit) preferably differ only in that they may be arranged (at each end of the central portion) in mirror symmetry (along the longitudinal axis of the central portion). Such a configuration may reduce the structural complexity of the overall nerve conduit, which may be sized to suit the requirements of the implantation site and / or specific nerve injury, and may further facilitate insertion of each nerve end in an opening having a larger cross-sectional area, since the elongate body may be configured for only a single nerve, effectively avoiding inadvertent misplacement in a compartment that does not correspond to the respective nerve end to be connected.

[0027] The tubular shape may provide a continuous outer dimension, which may be advantageous for implanting the nerve conduit relative to the surrounding tissue. Furthermore, the tubular or cylindrical shape may provide sufficient structural stability to prevent sharp bending or twisting during tissue movement, i.e., contraction or extension. The tubular shape may provide a homogenous structure that reacts in a predetermined manner along the entire central portion when a force is applied to the central portion (e.g., upon impact).

[0028] Furthermore, the tubular structure may substantially correspond to the shape of the internal cavity to provide a continuous guidance structure for neurogenesis or nerve growth, thereby facilitating proper growth and connection of the respective nerve ends without undesirable biasing, and achieving that the sizing of the internal cavity may be kept to a desired and / or necessary minimum.

[0029] The openings and the internal cavity may define a single lumen or a continuous through hole. In other words, a channel may be provided in the elongate body. The channel extends longitudinally from one end of the elongate body to the opposite end of the elongate body such that a (fluid) connection or communication is provided between the exteriors of the respective ends via the internal cavity. The internal cavity should be understood as a central lumen that extends and opens towards the respective end portions so that the nerve ends can be introduced into the lumen or through hole via the openings in the respective end portions. As mentioned above, the elongate body or portions of the lumen may comprise holes, pores, grooves, or specific geometric shapes or irregular surfaces, and / or fillers. This may facilitate the insertion, retention, and / or growth of the respective nerve ends. One or more of these features may be located on the interior or exterior of the elongate body, or may extend between the interior and exterior of the elongate body. Additionally, the elongate body, and particularly the lumen, may contain drugs, for example by coating or by being incorporated into the material of the elongate body, which may be released over time and may, for example, promote nerve growth.

[0030] Preferably, the cross-sectional area of ​​each of the plurality of openings is greater than the cross-sectional area of ​​the internal cavity. This has the advantage that the insertion and / or fixation of each of the respective nerve ends into the nerve conduit is facilitated, thereby further supporting the repair procedure of the respective nerve damage. The central portion may also be defined by the boundary area of ​​each end portion and / or between the openings. In this case, the longitudinal or axial extension of the central portion is substantially negligible (e.g., close to zero or less than, e.g., 10 percent of the minimum axial extension of each opening or end portion) compared to the corresponding extension of the end portions and / or openings. At least one opening of the plurality of openings may have a cross-sectional area different from at least one other opening at the opposite end of the central portion and / or may have a cross-sectional area that matches the cross-sectional area of ​​the internal cavity of the central portion, resulting in the formation of an asymmetric nerve conduit.

[0031] Although a larger cross-section of at least one opening is already advantageous in terms of the insertion and / or fixation of the respective nerve end(s), it is preferred that the cross-section of at least one of said openings increases as it moves away from said central portion in the longitudinal direction. In other words, the openings may increase along the longitudinal direction in the direction extending away from the central portion. If the central portion is of tubular construction, i.e. has a circular cross-section, the radial extension may preferably increase in all radial directions. On the other hand, if the central portion is of ellipsoidal construction, the radial extension may increase in at least one direction, i.e. the openings maintain their overall ellipsoidal shape or they change into a more circular shape. Preferably, the openings of each end portion increase starting directly from the central portion or increasing extending directly from the central portion.

[0032] The increasing opening may have various shapes. Although a radial flare at the boundary between the central portion and each end portion may be advantageous, for example, in handling the nerve conduit during implantation, it may be preferable for the opening to increase gradually and / or without steps to facilitate the insertion of each nerve end and / or provide a guide surface during insertion of each nerve end. In other words, the gradual increase in opening or cross-sectional area may direct the inserted nerve end into or toward the internal cavity, and may avoid the occurrence of bending or abrupt folding by appropriately deflecting or guiding each nerve end. Thus, this gradual increase in cross-sectional area may avoid stump trauma or any other adverse effects of each nerve end that may occur when the nerve end contacts an orthogonal and / or flat surface.

[0033] At least one of the end portions and the corresponding opening is preferably formed as a rotationally symmetric shape along a longitudinal axis defined by the elongate body, the shape being substantially U-shaped, sigmoidal, conical, concave, funnel or parabolic.

[0034] As outlined above, such shapes may provide a gradual increase in cross-sectional area. These preferred shapes should be understood as shapes extending substantially from the central portion, as shown in the longitudinal cross-section of the elongated body. These preferred shapes are preferably circumferentially continuous, i.e., do not form gaps, based on their rotational symmetry. These particular shapes may facilitate the advancement of the respective nerve end into the opening and further into the internal cavity, substantially without stress (pressure) or tension, since the contact between the nerve end and the internal surface of the end portion does not cause a significant bending of the nerve, but rather changes the direction of the nerve end or its tip in the direction of advancement, i.e., towards the internal cavity. In this way, the provided guiding surface or guiding structure facilitates the insertion procedure of the surgeon, while at the same time the respective nerve end is not adversely affected by the internal surface of the end portion during insertion.

[0035] Particularly advantageous embodiments in this regard include funnel and / or parabolic shapes of the end portions and corresponding openings, since these shapes can provide a substantially continuous and radially inward guide surface, i.e., toward the inner cavity of the elongate body. Furthermore, these shapes avoid steps or sharp edges or large changes in cross-sectional area toward the inner cavity or large differences in cross-sectional area at the intersection between the inner cavity and the opening extending from the inner cavity, while further improving the structural stability. The funnel shape can, for example, be substantially conically shaped or have a parabolic extension, for example with the same maximum cross-sectional area as the conical shape, but with a corresponding smaller longitudinal extension and / or a smaller angle with respect to the central portion.

[0036] At least one of the end portions may also comprise a star shape as shown in a cross-section of the end portion, which is preferably rotationally symmetrical. The wall of the elongate body at the end portion may have two or more rounded bulges with radially extending openings. The bulges may be equally spaced apart in the circumferential direction. Thus, the bulges form inner and outer grooves, which are defined by the circumferential width and radial extension of the respective bulges or by the distance between the two bulges. Such a shape may facilitate the insertion of the corresponding nerve end by increasing the respective opening. Furthermore, such a shape may facilitate the handling of the respective end portion by improving the gripping surface during surgery.

[0037] Thus, while the star shape by itself already provides an increased opening, such a star shape may also be provided with a gradually increasing cross-sectional area. For this purpose, such a star shape may be combined with, for example, a funnel shape and / or a parabolic shape at the respective end portions. Moreover, such a shape is not limited to the respective end portions, but may be provided for the entire elongate body so that the opposite end portions and the central portion may be formed in the same way. This allows for easier handling during implantation and during surgery. This may also be advantageous in terms of manufacturing. Furthermore, these preferred shapes mentioned above, in particular the funnel and / or parabolic shapes, facilitate the application of the medical adhesive, for example by keeping the applied medical adhesive substantially outside the internal cavity and / or by forming a joint or an outer edge or rim for the application of the medical adhesive. As a result, it is ensured that the respective nerve ends are retained within the nerve conduit, and leakage into the surrounding tissue and / or the central portion towards the internal cavity is prevented. These shapes may also define a limited reservoir or recess. This prevents the medical adhesive from entering the nerve conduit, for example if too much or imprecise application of the medical adhesive is applied, and ensures that the medical adhesive is kept at the joint or edge area. Furthermore, the grooves formed by the star-shaped cross section of each end portion may promote an increased contact area with the medical adhesive, thereby improving fixation of each nerve end to the end portion.

[0038] The end portions may be adapted to a particular size of nerve injury, and the nerve conduit as a whole may be sized to bridge the corresponding distance between the respective nerve ends. Thus, the end portions of the elongate body may be configured differently to provide different characteristics, for example to accommodate corresponding nerve ends of different sizes. However, the end portions are preferably formed the same. Thus, the nerve conduit may be implanted substantially independent of the orientation of the respective end portions. In other words, by shaping the end portions uniformly, the nerve conduit may be configured to be substantially mirror symmetric. Thus, the nerve conduit may be placed in either direction, i.e., 180 degrees inverted.

[0039] The inner cavity and the plurality of openings are preferably formed by a single wall of the elongate body that defines the inner and outer diameters of the elongate body. This may result in a more robust nerve conduit that responds in a predetermined and / or predictable manner to forces acting on the elongate body, and may reduce the structural complexity of the nerve conduit. For example, compressive and / or tensile forces acting on the elongate body may be better distributed (or absorbed) by a single wall, so that stress (pressure) or tension concentrations are avoided. Furthermore, depending on the material of the elongate body, for example if the elongate body is formed from a wall with elastic and / or resilient properties, the deflection of the nerve conduit may be more uniform.

[0040] In certain circumstances, the wall may have a thickness that decreases in at least one of the end portions starting from the central portion toward the outermost (longitudinal) end of the respective end portion. In this way, a larger cross-sectional area of ​​the opening may be defined by the thickness of the wall.

[0041] However, the wall preferably has a substantially continuous thickness along the circumferential and longitudinal directions of the elongate body. This not only facilitates the manufacture of the nerve conduit, but also ensures that similar structural properties are provided along the longitudinal and circumferential directions. Providing a continuous wall thickness, as opposed to a beveled or chamfered end portion, facilitates a gradual increase in the diameter and / or cross-sectional area of ​​the end portion over a greater longitudinal extent due to improved structural properties. Such a continuous thickness may be provided by a minimum continuous thickness over the entire longitudinal extent of the elongate body, or the thickness may exceed the minimum extension in certain portions, preferably in one or more end portions. Furthermore, the proper placement of the nerve conduit is not dependent on the orientation of the nerve conduit in the circumferential direction.

[0042] It is preferred that the inner and outer diameters of the central portion are substantially continuous along the length of the elongate body so as to provide a substantially homogenous internal cavity which is advantageous in optimizing nerve growth conditions and in allowing the growing nerve ends to be properly guided without undesirable bias.

[0043] The diameter of at least one of the openings may increase as it moves away from the central portion in the longitudinal direction. In other words, the larger cross-sectional area of ​​the corresponding opening may be determined by the inner diameter of the wall. In this case, the diameter increases away from the central portion and / or starting (directly) from the central portion towards the longitudinal ends of the end portions. The increase in the openings is preferably gradual and homogeneous in any radial extension. For example, the cross-section of the openings may be circular along the entire longitudinal direction of the respective end portion. In this case, the diameter of the circular shape increases gradually. Such a shape has the further advantage that the positioning of the nerve conduit during implantation is independent of the rotational orientation. However, other shapes (e.g. ellipsoid, etc.) are also possible. In this case, the (gradual) increase in the openings is caused by an increase in at least one radial extension.

[0044] The largest or maximum diameter of the at least one opening may be selected such that insertion of the respective nerve end is adequately supported while maintaining the overall thickness of the nerve conduit within physiologically acceptable limits. Thus, the maximum diameter is selected such that the accommodated nerve end is adequately supported by the end portion while avoiding pressure and / or friction points against the surrounding tissue.

[0045] Correspondingly, the ratio of the maximum diameter of at least one of the openings to the diameter of the internal cavity is preferably 1.05:1.0 to 1.5:1.0, preferably 1.05:1.0 to 1.2:1.0. It has been found that the difference in diameter, and therefore in cross-sectional area, can then be relatively small. Nevertheless, with this preferred ratio, a further improvement is achieved with regard to the insertion and / or fixation of the respective nerve ends. With a smaller ratio, the application of the medical adhesive is further improved, since this further reduces the risk of applying adhesive between the respective nerve ends into the internal cavity of the central part.

[0046] The maximum (internal) diameter of at least one of the openings is preferably smaller than or corresponds to the outer diameter of the central portion, i.e., viewed in longitudinal section, the openings do not radially exceed the outer diameter of the inner cavity. As a result, depending for example on the wall thickness and the dimensioning of the inner cavity, the maximum diameter of the openings can be relatively small so that the overall appearance is maintained and / or a large radial protrusion from the central portion is avoided.

[0047] The outer surfaces of the end portions extending from the central portion are preferably aligned with respect to the outer surface of the central portion. In some embodiments, the outer surfaces of the end portions extending from the central portion may be free of steps or edges with respect to the outer surface of the central portion. According to a preferred embodiment, the outer surfaces of the end portions extending from the central portion may further support or comprise an exterior structure having a particular geometric shape or an irregular surface shaped to form a retention surface, such as holes, grooves or striations.

[0048] The maximum outer diameter of the end portion(s) is preferably greater than the (maximum) outer diameter of the central portion. The outer ends of the end portions (constituting the ends of the nerve conduit) are preferably provided (formed) by a continuous edge, preferably having a substantially circular or ellipsoidal shape (in cross-section). In particular, the edges forming the outer ends of the end portions preferably do not include any recesses or cut-outs. As a result, the nerve can be more easily inserted into the nerve conduit. In some embodiments, the (outer surface of) the end portion may have a substantially frusto-conical shape.

[0049] In particular, the minimum outer diameter of the (frustoconical) end portion(s) may match the outer diameter of the (tubular, e.g. substantially cylindrical) central portion. This may provide a smooth transition between the central and end portions on the outside of the nerve conduit. The minimum inner diameter of the (frustoconical) end portion(s) may match the inner diameter of the (tubular, e.g. substantially cylindrical) central portion. This may provide a smooth transition between the central and end portions on the inside. As a result, the nerve conduit may have enlarged ends (compared to the central portion) to facilitate nerve insertion, and the wall thickness of the nerve conduit may be kept to a minimum. This may provide good flexibility. Also, less material may be used. In some embodiments, the nerve conduit may have substantially the same wall thickness over its entire length, i.e. in the end portion(s) and the central portion.

[0050] The maximum (inner and outer) diameter of the (frusto-conical) end portion(s) typically constitutes the end(s) of the nerve conduit. Preferably, there is no (second) cylindrical portion adjacent the larger end(s) of the (preferably frusto-conical) end portion(s).

[0051] In a preferred embodiment, the internal cavity of the central portion defines a single lumen (preferably the nerve conduit comprises a central portion having a substantially tubular shape (with a single internal cavity)) and the nerve conduit comprises two end portions, one at each end of the central portion. In this case, the maximum outer diameter of the end portions is preferably greater than the outer diameter of the central portion, and the outer ends of the end portions (constituting the ends of the nerve conduit) are provided (formed) by a continuous edge (without any recesses or cutouts). The two end portions preferably differ from each other only in that they are arranged (configured) as mirror images (along the longitudinal axis of the central portion).

[0052] To accommodate the various lengths bridged by the nerve conduit, the nerve conduit may be formed in various dimensions. Thus, the length of the central portion and the length of the end portion (or each end portion) in the longitudinal direction may differ from each other for a given configuration. Preferably, the ratio of the length of the central portion to the length of the end portion in the longitudinal direction is 1.2:1.0 to 15:1.0, preferably 1.2:1.0 to 12:1.0, more preferably 1.2:1.0 to 10:1.0. In some embodiments, the ratio of the length of the central portion to the length of the end portion in the longitudinal direction is preferably 1.2:1.0 to 6.0:1.0, more preferably 1.2:1.0 to 1.4:1.0, or 1.8:1.0 to 2.2:1.0, or 4.4:1.0 to 5.4:1.0.

[0053] The ratio may depend on the total or absolute length of the nerve conduit or elongate body. For example, for conduits with smaller dimensions, the ratio may be larger. In particular, for nerve conduits with smaller dimensions, the larger ratio may be used, i.e., 4.4:1.0 to 5.4:1.0. In this case, the end portions are smaller than the central portion.

[0054] Similarly, the ratio of the length of the central portion to the length of the elongate body in the longitudinal direction may be 0.3:1.0 to 1:1.0, for example 0.3:1.0 to 0.8:1.0. Such ratio may increase as the overall length of the elongate body decreases. As a result, the length of the elongate body may be determined primarily by the central portion and may include only small end portions for nerve conduits having relatively small or minimal dimensions.

[0055] Since the length of the end and central portions is dependent on the overall length, the end portions may be longer if a greater distance is bridged between the corresponding nerve ends, e.g., due to trauma. In this case, the longer end portions may extend along the longer corresponding portions of each nerve end. This may provide additional structural stability, since the end portions may be configured to accommodate a (larger amount of) medical adhesive.

[0056] The length of the central portion in the longitudinal direction may be 3 mm to 40 mm, preferably 4 mm to 30 mm, more preferably 4.5 mm to 25 mm, for example 5 mm to 10 mm or 6.5 mm to 8.5 mm. The length of the elongate body in the longitudinal direction may be 5 mm to 50 mm, preferably 6 mm to 40 mm, more preferably 7 mm to 30 mm, for example 7 mm to 25 mm or 9 mm to 22 mm. The length of the (one or more) end portion (of each end portion) in the longitudinal direction may be 1 mm to 8 mm, preferably 1.3 mm to 6.5 mm. These dimensions have been found to be particularly advantageous for bridging nerve defects or damage while facilitating insertion and / or fixation of nerve ends.

[0057] The diameter of the inner cavity may be between 1 mm and 15 mm, preferably between 1 mm and 12 mm, for example between 1 mm and 12 mm or between 1.5 mm and 6.5 mm. The maximum diameter of at least one of the openings may be between 1 mm and 15 mm, preferably between 1.5 mm and 13 mm, for example between 1.5 mm and 7.5 mm, more preferably between 1.75 mm and 7 mm, for example between 1.75 mm and 6.5 mm. Again, such dimensions have been found to be particularly advantageous in providing the necessary support for the nerve ends and nerve growth whilst facilitating insertion and / or fixation of the nerve ends.

[0058] The elongate body may be formed from a biocompatible, inert, bioimplantable, and / or biodegradable material. The material may be selected to provide a certain structural stability while substantially avoiding or at least reducing an inflammatory response in the patient being treated. For example, a biocompatible material may be selected that will gradually degrade over time after implantation, but may initially provide sufficient structural support to properly repair nerve damage, to ensure that the respective nerve ends are properly and sufficiently stably connected, for example during tissue movement.

[0059] Furthermore, certain materials may be selected to promote or support nerve growth, for example by comprising or incorporating or including a corresponding coating with a biologically active agent and / or one or more neurotrophic factors. Other examples of such biologically active surface functionalities include, but are not limited to, for example, anti-inflammatory agents, immunosuppressants, and neuroprotective agents. The bioactive agents may be surface bound and / or entrapped in the structures (e.g., the walls described above) that define the elongated body. Examples of such bioactive agents are cytokines, nerve growth factors, hyaluronic acid, tacrolimus, cyclosporin A, melatonin, vitamin B12, methylprednisolone, riluzole, taxol, cetuximab. A preferred example is tacrolimus.

[0060] Preferably, the elongate body is made of a polymer-based material, preferably an elastomer, with the advantage that multiple manufacturing methods can be applied and / or specific material properties can often be obtained, for example based on the polymer units. In particular, the polymer-based material may be a biocompatible material, which further has elastic properties so that the nerve conduit, in the implanted state, can adapt to the movements of the tissue surrounding the repaired nerve injury.

[0061] The elongate body may be formed from polymerized and / or crosslinked polymer units comprising an ester group component and an acidic ester group component, the ester group component preferably being a polyol and the acidic ester group component preferably being a polyacid.

[0062] The material used for the central portion may be the same as that of the end portions, which may facilitate easier manufacturing and may provide substantially uniform structural properties of the elongate body along the length of the nerve conduit. In this case, biodegradation (and / or bioabsorption) may occur in a predetermined or expected manner if the nerve conduit is configured accordingly. However, at least one end portion of the multiple end portions may be formed from a different material than the central portion and / or the opposing end portion. Such a configuration may be advantageous, for example, when one end portion has a specific functionality that may require different properties (e.g., when the end portion is configured as a primary inlet for application of a medical adhesive).

[0063] Preferably, the central portion and the end portions are integrally formed or formed from a single piece. In other words, the elongate body preferably does not require specific connections between the central portion and the end portions. Instead, it provides for a material bond provided by the material of the central portion and / or the end portions, and the corresponding structural integrity of the respective elements. By providing the elongate body as a single piece, the robustness of the nerve conduit may be further improved, since providing separate connections between components is effectively avoided.

[0064] Said nerve conduit may be formed by a 3D printing process. This is particularly advantageous when the material of the nerve conduit is polymer-based (for example, as described in WO2019 / 180208). In this case, the hardening of the material can be performed virtually instantly, for example, using (UV) light. Furthermore, this allows a level of precision that cannot be (easily) achieved by extrusion and / or dipping processes. In particular, the 3D printing process allows a specific shape of the nerve conduit to be obtained. In this case, for example, the printing process can incorporate specific bioactive agents into the 3D structure according to a predetermined pattern, for example, into the mesh structure, and / or in particular into the pockets or cavities formed by the 3D structure. As a result, the orchestration and support of the nerve repair can be further improved and / or biodegradation can be achieved with more controllable materials.

[0065] In some embodiments, the nerve conduit of the present invention may be used in combination with an apparatus for applying adhesive (applicator), for example an apparatus for applying adhesive as described in WO 2022 / 048799 A1.

[0066] It may be advantageous to fix the medical adhesive to the nerve conduit to ensure that relative movements between the medical adhesive and the respective end region are reduced or avoided under normal physiological behavior. At least one end portion of the plurality of said end portions may then comprise one or more retention surfaces on the outer surface of said elongate body, in particular on the outer surface of said end portion(s). In this case, said retention surface(s) is / are particularly configured to fix the medical adhesive to the respective end portion. As a result, the medical adhesive applied to the respective end region and / or the corresponding nerve end may remain in place without any significant movement even after the medical adhesive has hardened. In other words, the retention surface may hold the medical adhesive in place, preferably conformally against the retention surface(s). The retention surface may increase the contact surface with the medical adhesive. Furthermore, the retention surface may provide a predetermined surface roughness, which may improve the effectiveness of the medical adhesive bonding with the respective end region. Thus, loosening or slipping of the medical adhesive can be effectively prevented by the surface and / or shape of the retention surface. In some embodiments, the (outer surface of) the end portion(s) is / are structured, i.e., the (outer surface of) the end portion(s) includes a structure. In particular, such a structure of the (outer surface of) the end portion(s) forms a "retention surface". Advantages of the end portion(s) having a structure or retention surface include (i) increasing the contact between the surface of the end portion and the adhesive / guide, and (ii) creating a fixation point for the adhesive.

[0067] In some embodiments, the retention surface(s) of each end portion may be formed as a plurality of (e.g. ellipsoidal or circular) holes which may be arranged in at least one row in the circumferential direction of the elongate body. The holes may be arranged linearly along the circumference of the elongate body. The number of rows is preferably in the range of 1 to 10 rows. Each row preferably comprises 2 to 20 holes. In this case, the holes may advantageously be equally spaced in the circumferential direction of the elongate body. Preferably, the holes are arranged in 2 to 4 rows and / or each row comprises 4 to 8 holes. In this case, the plurality of holes in adjacent rows are preferably arranged in a staggered manner. For example, two rows may be provided in each end region. In this case, each row may comprise, for example, 6 holes.

[0068] The number of holes and rows and their arrangement have been found to be advantageous in providing and maintaining the necessary structural stability while improving retention for securing the medical adhesive to the nerve conduit. Furthermore, such embodiments may exhibit rotational symmetry, which may facilitate accurate insertion and placement of the nerve conduit at the target tissue site. In certain embodiments, the size or diameter of the holes may be between 50 μm and 750 μm, and for further improvement of structural stability, the size or diameter of the holes may be preferably in the range of 150 μm to 600 μm, and in particular, about 500 μm.

[0069] Each hole may be formed as a cutout, recess or through-hole in the wall forming said elongate body. This may result in improved fixation of the medical adhesive. In particular, through-holes may be further advantageous. Such preferred through-holes may facilitate the medical adhesive to surround the elongate body at each end portion, in particular both outside and inside the nerve conduit. This may depend on the selected dimensions and / or, in particular, the diameter of the hole. This may further result in contact of the medical adhesive with each nerve end to be inserted. The holes may have a radial height or depth corresponding to the strength of the wall defining (making) the elongate body, but may also have a reduced height. Preferably, the holes have a height or depth of 40 μm to 60 μm, or a height or depth of about 50 μm.

[0070] In some embodiments, the retention surface or surfaces of each end portion may be formed as at least one groove extending in a helical direction along a longitudinal axis defined by the elongate body, the helical shape defining striations extending along the outer surface of each end portion.

[0071] Although one or more of the grooves may define sharp edges, at least one of the grooves preferably includes rounded edges, which should be understood to be such that at the boundary of the top outer surface of each end portion and at the opposing bottom surface of the groove with the wall defining the elongated body, there is no straight edge or step, but instead a gradual transition at the corner face of the groove. The rounded edges may reduce stresses in the material of the elongated body, thereby reducing the occurrence of breakage or fracture. By providing rounded edges, the required thickness of the wall defining the elongated body may be reduced, at least at the end portion supporting the groove.

[0072] Alternatively, or in addition to (preferably) rounded edges, at least one of said grooves may define at least one undercut. By providing an undercut, fixation of the medical adhesive to the respective end portion may be improved. The undercut may be formed such that a bottom portion of the groove is at least partially covered by the outer surface of the wall. That is, the outer wall of the elongate body may at least partially extend longitudinally over the groove. Preferably, such extension forms an angle (between the side wall and the bottom of the groove) of between 45° and 90°, preferably between 60° and 85°, more preferably between 70° and 80°, even more preferably about 75°. This may improve the form fit or secure fixation between the applied medical adhesive and the respective end portion.

[0073] To reduce the radial extent of the elongate body and the nerve conduit as a whole, at least one of the grooves may define the outermost edge of each of the end portions in the longitudinal direction of the elongate body. The groove may thus terminate at the end face of the end portion facing the side of the central portion and extend along the entire circumference of the end face, so that the radial extent may be reduced at the end. Thereby, the overall dimensioning of the nerve conduit may be reduced. Alternatively, the groove may terminate offset longitudinally relative to the end face. This may be advantageous to further improve structural stability.

[0074] The depth or thickness of the groove may be substantially constant along the circumference and throughout its longitudinal extension. In an alternative embodiment, at least one said groove may have a radial depth that varies as the cross-sectional area of ​​at least one said opening increases longitudinally away from said central portion. According to a preferred example, the inner radius of the groove may be continuously maintained and the outer radius of the groove may increase corresponding to an increase in the total size of the openings, provided that the thickness of the corresponding wall portion increases in the same way.

[0075] The extent and / or angle of the at least one groove may vary. Preferably, the at least one groove extends 0.5 to 10 turns around the longitudinal axis defined by the elongate body, so that a helical structure is provided (at the end portion(s)). Preferably, the groove extends more than one turn around the longitudinal axis defined by the elongate body. In particular, the number of turns may be 2 to 6, preferably 3 to 5, or even 4.

[0076] In some embodiments, the end portion (or each of the two end portions) may comprise a single groove. In other embodiments, each of the end portions (one or more) may comprise at least two grooves. In particular, when two or more grooves are provided in the same end portion, each groove may extend for 0.5 to 5 revolutions around the longitudinal axis. The at least two grooves may extend parallel, for example forming two or more parallel (non-intersecting) spirals. As a result, the arc length, curvature and torsion of the parallel grooves / spirals are preferably the same, only differing in their position (on the end portion). Preferably, the distance between the two or more parallel grooves / spirals is regular (i.e. approximately the same). In some embodiments, the at least two grooves may extend in opposite circumferential directions and intersect each other. Both embodiments may be combined. That is, two or more grooves may run parallel and in opposite circumferential directions two or more additional grooves may also run parallel (such that parallel intersecting grooves create a "checkered" or "pineapple" pattern). The number of grooves in each circumferential direction may be 1-10, preferably 6-8, or 7, depending on the longitudinal extent of the respective end portion and the groove angles. Furthermore, the number of grooves is preferably equal for each circumferential direction. Furthermore, in a single end portion (or in each end portion), the grooves / spirals preferably differ only in their direction (and position on the end portion), but not in other helical parameters. In other words, the arc length, curvature and torsion may be substantially the same for all grooves / spirals in a certain end portion (except for the direction of the intersecting helices). By providing multiple grooves (e.g., two or more grooves) in each circumferential direction, a diamond or lozenge shaped pattern is created on the outer surface of each end portion, which may resemble a pineapple surface. As a result, multiple retention surfaces with multiple edges may be created, which may be advantageous for securing a medical adhesive to each end portion.

[0077] In some embodiments, the retention surface or surfaces at each end portion may be formed as one or more circumferential ribs extending from the outer surface of the elongate body. The rib or ribs may be arranged in a linear fashion along the circumferential direction of the elongate body or may be arranged at an angle to the circumferential direction. Preferably, when there are multiple ribs, for example 3 to 6 ribs, at each end portion, the ribs may be equally spaced from each other and the ribs are non-intersecting, i.e. preferably parallel to each other.

[0078] The retention surface or surfaces may generally be provided on thickened wall portions at each end portion, adapted to the desired implementation of the retention surface and the structural requirements at the end portion. Preferably, the thickness of the wall portion at each end portion may be 1.0 to 3.5 times the thickness of the adjacent central portion. For example, if the wall thickness of the central portion is about 200 μm, the wall thickness at the end portion may be 200 μm to 700 μm, preferably 300 μm to 500 μm, or 400 μm, i.e., including an additional thickness of 100 μm to 300 μm. In another embodiment, if the wall thickness of the central portion is about 20 μm, the wall thickness at the end portion may be 20 μm to 70 μm, preferably 30 μm to 50 μm, or 40 μm, i.e., including an additional thickness of 10 μm to 30 μm. The thickened wall portion may be made flush with the outer surface of the central portion by appropriate radiusing or filleting.

[0079] Furthermore, one or more holes, in particular grooves, may be provided as positive features in the outer surface of a wall of an elongate body that otherwise has a substantially continuous thickness. The wall may comprise a positive protrusion or build-up at each end portion that defines a respective groove or hole, while the central portion does not comprise such a positive feature. In such a case, the outer surface of the wall preferably defines an inner radius of each groove or hole.

[0080] To enhance the effectiveness of the medical adhesive, and preferably to improve the conformability or interlock between the medical adhesive and the nerve conduit, the retention surface may further be included at least partially on a portion of the central portion immediately adjacent to each end portion. For example, at least one row of holes may be provided on the central portion, e.g., staggered relative to adjacent rows on the end portions, or one or more grooves may extend across the immediately adjacent portions of the central portion (e.g., beginning at or terminating at the central portion). Such extension of the retention surface may provide a gradual transition of the retention surface and improve load distribution over the elongate body.

[0081] Only one end portion of each of the nerve conduits may be provided with one or more retaining surfaces. Preferably, all end portions (of the same nerve conduit), in particular all of the opposing end portions, e.g. two opposing end portions, are provided with one or more retaining surfaces. The end portions (of the same nerve conduit) may have different types of retaining surfaces, i.e. one end portion may be provided with grooves and the other end portion with holes. However, it is preferred that the end portions (in particular of the opposing ends of the nerve conduit or of all ends of the nerve conduit) have similarly shaped retaining surfaces. The retaining surfaces of the opposing end portions may be mirror symmetrical with respect to a mid-plane transverse to the elongate body, e.g. such that they are aligned in opposite directions. For example, each of the opposing end portions (of the same nerve conduit) may be provided with a single or multiple grooves / spirals as described above. In this case, the grooves or spirals of the different end portions may substantially correspond to each other (e.g., have the same number and / or the same pattern), but the different end portions (of the same nerve conduit) differ from each other in that the grooves / spirals are formed in a mirror arrangement with respect to a mid-plane that transverses the elongate body, so that they are oriented in opposite directions. For example, in one end portion, the grooves may extend in a clockwise direction, while in the other end portion (of the same nerve conduit), the grooves may extend in a counterclockwise direction. However, the retention surfaces of different end portions of the same nerve conduit may alternatively be oriented or disposed in the same direction, e.g., have grooves or striations in the same (clockwise or counterclockwise) direction.

[0082] The above objects are also achieved by the use of the nerve conduit described above for repairing, supporting and / or guiding nerve tissue, in particular for repairing peripheral nerve injuries. Furthermore, the nerve conduit may be used in combination with a medical adhesive.

[0083] According to another aspect of the present invention, 1. A method for treating peripheral nerve injury, comprising: - providing a nerve conduit as described above; - inserting one end of an injured nerve into the nerve conduit through an opening having a cross-sectional area larger than the inner cavity of the central portion; - inserting another end of the damaged nerve through an opening in an end portion at a longitudinally opposed end of the elongate body; - fixing a plurality of said injured nerve ends within said elongate body; A method is proposed, which includes:

[0084] The step of fixing the damaged nerve ends is preferably performed by applying a medical adhesive to the outside of the internal cavity and / or within the openings through at least one of the openings.

[0085] The medical adhesive according to the present invention may be any medical adhesive in the art. In some embodiments, the medical adhesive may polymerize when exposed to light. Prior to such polymerization, the medical adhesive may be fluid or viscous.

[0086] In some embodiments of the invention, the medical adhesive includes a prepolymer comprising polymer units of the general formula (-AB-)n, where A represents a substituted or unsubstituted ester, B represents a substituted or unsubstituted acid ester comprising at least two acid ester functional groups, and n represents an integer greater than 1.

[0087] Component A may be derived from a polyol, such as a diol, triol, tetraol or higher polyol. Suitable polyols include diols, such as alkanediols; triols, such as glycerol, trimethylolpropane, triethanolamine; tetrads, such as erythritol, pentaerythritol; and higher polyols, such as sorbitol. Unsaturated diols, such as tetradeca-2,12-diene-1,14-diol, or other diols, including macromonomer diols, such as polyethylene oxide and N-methyldiethanoamine (MDEA), may also be used. The polyol is preferably substituted or unsubstituted glycerol.

[0088] Component B may be derived from a polyacid (e.g., a diacid or higher acid). A wide variety of diacids or higher acids may be used. Exemplary acids include, but are not limited to, citric acid (3 carbons), glutaric acid (5 carbons), adipic acid (6 carbons), pimelic acid (7 carbons), sebacic acid (8 carbons), and azelaic acid (9 carbons). Exemplary long chain diacids include diacids with more than 10 carbon atoms, diacids with more than 15 carbon atoms, diacids with more than 20 carbon atoms, and diacids with more than 25 carbon atoms. Non-aliphatic diacids may also be used. For example, versions of the above diacids with one or more double bonds may be used to produce polyol-diacid copolymers. The diacid is preferably substituted or unsubstituted sebacic acid.

[0089] Multiple substituents (e.g., amines, aldehydes, hydrazides, acrylates, and aromatic groups) can be incorporated into the carbon chain. Exemplary aromatic diacids include terephthalic acid and carboxyphenoxypropane. Polyacids (e.g., diacids) can also include substituents. For example, reactive groups such as amines and hydroxyls can be used to increase the number of sites available for crosslinking. Amino acids and other biomolecules can be used to modify biological properties. Aromatic groups, aliphatic groups, and halogen atoms can be used to modify interchain interactions within the polymer.

[0090] The prepolymer may further comprise a polyamide or polyurethane backbone. For example, a polyamine (containing two or more amino groups) may be used, either together with a polyol or after it has been reacted with a polyacid. In another example, a polyisocyanate (containing two or more isocyanate groups) may be used, either together with a polyol or after it has been reacted with a polyacid.

[0091] The prepolymer is preferably capable of being activated. The prepolymer may be activated by introducing a functional group that can react or be made to react to form crosslinks. Suitable functional groups that are activated on the prepolymer backbone include hydroxy groups, carboxylic acid groups, amines, and combinations thereof, preferably hydroxy and / or carboxylic acid. Free hydroxyl or carboxylic acid groups on the prepolymer may be activated by functionalizing the hydroxy groups with moieties that can form crosslinks between polymer chains. The groups that are activated may be free hydroxyl or carboxylic acid groups on the A and / or B moieties in the prepolymer. Preferably, the functional group is or contains an acrylate group. The acrylate group is a moiety that contains a substituted or unsubstituted acryloyl group. The acrylate may contain the following group: -C(=0)-CR1=CR2R3. wherein R1, R2, R3 are each independently selected from the group consisting of H, alkyl such as methyl or ethyl, aryl such as phenyl, substituted alkyl, substituted aryl, carboxylic acid, ester, amide, amine, urethane, ether, and carbonyl.Preferably, R1, R2, and R3 are H; or R1 is CH3, R2 and R3 are H; or R1 and R2 are H, R3 is CH3; or R1 and R2 are H, R3 is phenyl.

[0092] Preferably, at least a portion of the activated groups (e.g., acrylate) on the polymer backbone of the prepolymer are reacted with a compound containing a charged atom, preferably a compound containing a positively charged nitrogen atom.

[0093] Preferably, the medical adhesive is a light curable compound. "Light curable compound" refers to a compound configured to polymerize or otherwise harden upon receipt of suitable radiant energy, more particularly, radiant energy in the form of light from a light source.

[0094] Preferably, the photocurable compound comprises a prepolymer and a photoinitiator, the photoinitiator capable of inducing polymerization of the prepolymer upon exposure to light of a particular wavelength.

[0095] In some embodiments, the photoinitiator is sensitive to ultraviolet (UV) radiation. Examples of suitable photoinitiators sensitive to UV radiation include 2-dimethoxy-2-phenyl-acetophenone, 2-hydroxy-1-[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone (Irgacure 2959), 1-hydroxycyclohexyl-1-phenyl ketone (Irgacure 184), 2-hydroxy-2-methyl-1-phenyl-1-propanone (Darocur 1 173), 2-benzyl-2-(dimethylamino)-1-[4-morpholinyl)phenyl]-1-butanone (Irgacure 369), methyl benzoyl formate (Darocur MBF), oxy-phenyl-acetic acid-2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester (Irgacure 369). 754), 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone (Irgacure 907), diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (Darocur TPO), phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl) (Irgacure 819), and combinations thereof.

[0096] In some embodiments, the photoinitiator is sensitive to visible light (typically blue or green light). Examples of photoinitiators sensitive to visible light include, but are not limited to, diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide, eosin Y disodium salt, N-vinyl-2-pyrrolidone (NVP) and triethanolamine, and camphorquinone.

[0097] In addition, the medical adhesive may contain one or more pharmaceutical, therapeutic, or prophylactic agents that may be released during the time the material functions as an adhesive. The agents may be small molecule agents (e.g., having a molecular weight of less than 2000, 1500, 1000, 750, or 500 Da), biomolecules (e.g., peptides, proteins, enzymes, nucleic acids, polysaccharides, growth factors), cell adhesion sequences (e.g., RGD sequences) or integrins, extracellular matrix components, or combinations thereof. Exemplary classes of small molecule agents include, but are not limited to, anti-inflammatory agents, analgesics, antimicrobial agents, and combinations thereof.

[0098] Preferably, the medical adhesive is or includes polyglycerol sebacate acrylate (PGSA) or PGSAA (e.g., as described in WO2021078962). [Brief description of the drawings]

[0099] The present disclosure will be more readily understood by reference to the following detailed description considered in conjunction with the accompanying drawings, in which: [Figure 1] 1 shows a schematic diagram of a longitudinal section of a nerve conduit according to the present invention. [Diagram 2] FIG. 2 shows a schematic diagram of a longitudinal section of the nerve conduit according to the invention according to FIG. 1 with alternative end portions. [Diagram 3] 3 shows a schematic diagram of the nerve conduit according to FIG. 2 in a side view from one end portion. [Figure 4] FIG. 3 is a schematic perspective view of the nerve conduit according to FIG. 2. [Diagram 5] 1 shows a schematic diagram of a longitudinal section of a nerve conduit according to the present invention, according to another embodiment. [Figure 6] 1 shows a schematic diagram of a longitudinal section of a nerve conduit according to the present invention, according to another embodiment. [Figure 7] 1 shows a schematic representation of a nerve conduit according to the present invention having a star-shaped configuration. [Figure 8] 1 shows a schematic representation of a nerve conduit according to the present invention having a star-shaped configuration. [Figure 9] FIG. 2 shows a schematic diagram of a perspective side view of a nerve conduit according to the present invention having end portions with alternative retention surfaces. [Figure 10] FIG. 2 shows a schematic diagram of a perspective side view of a nerve conduit according to the present invention having end portions with alternative retention surfaces. [Figure 11] FIG. 2 shows a schematic diagram of a perspective side view of a nerve conduit according to the present invention having end portions with alternative retention surfaces. [Figure 12] FIG. 11 shows a schematic diagram of an undercut defined by a groove according to FIG. 10; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0100] The present invention will now be described in more detail with reference to the accompanying drawings, in which like elements are given the same reference numerals and repeated descriptions may be omitted to avoid redundancy.

[0101] In FIG. 1, a nerve conduit 10 according to the present invention is shown diagrammatically along a longitudinal section. The nerve conduit 10 comprises an elongate body 12 having a central portion 14. The central portion 14 defines an internal cavity 16. In this embodiment, the internal cavity 16 is substantially defined by a wall 22. The wall 22 has a continuous tubular or cylindrical shape along the length of the elongate body 12 and has a continuous thickness both circumferentially and longitudinally. As a result, the internal cavity 16 is formed as a cavity having a cylindrical shape with a substantially continuous dimension. However, it will be appreciated that embodiments of the present invention are not limited to such configurations and that the central portion 14 and the internal cavity 16 may have various wall thicknesses and / or alternative shapes.

[0102] According to this exemplary embodiment, the nerve conduit 10 or its elongate body 12 comprises two end portions 18. The two end portions 18 are located at longitudinally opposed ends of the elongate body 12 and are located directly adjacent to the central portion 14. As shown in the schematic diagram of FIG. 1, the outer surfaces of both end portions 18 are aligned or end-to-end with respect to the outer surface of the central portion 14 so as to provide a homogenous, step-free outer surface without sharp edges, recesses, and / or protrusions that may adversely affect surrounding tissues when the nerve conduit 10 is in an implanted state.

[0103] The end portions 18 define openings 20 into the internal cavity 16 such that a continuous through-hole is provided from one end of the elongate body 12 to the opposite end of the elongate body 12 and fluid communication is provided between the internal cavity 16 and the exterior of the elongate body 12. Multiple nerve ends of a nerve to be repaired may be inserted into the internal cavity 16 through respective openings 20 in the corresponding end portions 18, for example, after trauma resulting in nerve injury. The multiple end portions 18 in this embodiment are similarly shaped and dimensioned so that reverse orientation of the nerve conduit 10 during implantation does not affect the procedure.

[0104] The openings 20 of each of the end portions 18 of the plurality of end portions increase in the direction away from the central portion 14 along the longitudinal direction of the elongated body 12. In other words, each opening 20 or its radial extension increases (gradually) starting from or extending from the central portion 14. In this exemplary embodiment, the openings 20 increase gradually due to the conical shape of the end portion 18 or its wall 22. Thus, as a result of the continuous wall thickness and the shape of the central portion 14 and the end portion 18, the cross-sectional area of ​​each opening of the plurality of openings 20 is larger than the cross-sectional area of ​​the internal cavity 16 of the central portion 14. As a result, the insertion of the respective nerve end into the internal cavity 16 and the application of the medical adhesive outside the internal cavity 16, especially at the edge region or junction of the opening, may be facilitated.

[0105] Both the inner cavity 16 and the openings 20 have a substantially circular shape in cross-section. The diameter 26 of the inner cavity 16 is substantially continuous. The diameter of each opening of the plurality of openings 20 at the interface with the central portion 14 or the inner cavity 16 substantially matches the diameter 26 of the inner cavity 16. However, the diameter of each opening of the plurality of openings 20 increases along the longitudinal direction away from the central portion 14 and toward the outermost ends of the elongated body 12 and end portions 18, respectively. Thus, in this embodiment, the largest diameter 24 and / or radial extent, and thus the largest cross-sectional area, of each opening of the plurality of openings 20 is at the longitudinally opposed outermost ends of the elongated body 12. Having the greatest cross-sectional area at the outermost end of the elongate body 16 makes it easier to insert the respective nerve ends and / or to apply a medical adhesive outside the internal cavity 16, or at the boundary between the internal cavity 16 and the respective openings 20, or at the boundary between the respective openings 20 and the respective inserted nerve ends.

[0106] In FIG. 2 a nerve conduit 10 is shown, which corresponds substantially to the embodiment according to FIG. 1. However, this embodiment differs with regard to the shape of the end portion 18. In this embodiment, the end portion 18 is funnel-shaped and defines a radially outward curvature or parabolic extension starting from the end facing the central portion 14 and extending towards the outermost end of the elongated body 12. In this way, a larger opening 20 can be provided at the outermost end without having to increase the length of the end portion 18 in the longitudinal direction and without having to provide a large angular offset at the boundary between the central portion 14 and the respective end portion 18. As a result, the structural stability of the nerve conduit 10 is also improved. Moreover, such a shape can be advantageous to avoid a sharp bend of the respective nerve end during insertion by providing a gradual guiding surface towards the inner cavity 16.

[0107] 2, the maximum diameter 24 of the opening 20 is greater than the (constant) diameter 26 of the inner cavity 16. Additionally, FIG. 2 illustrates possible ratios between these diameters 24, 26, and the length ratios between the corresponding portions 14, 18 of the elongate body 12.

[0108] For example, the ratio of the maximum diameter 24 of the opening 20 to the diameter 26 of the inner cavity 16 may be 1.05:1.0 to 1.2:1.0. The maximum diameter 24 of the opening 20 may be 1 mm to 15 mm, preferably 1.5 mm to 13 mm (e.g., 1.5 mm to 7.5 mm), and more preferably 1.75 mm to 7 mm (e.g., 1.75 mm to 6.5 mm). The diameter 26 of the inner cavity 16 may be 1 mm to 15 mm, preferably 1 mm to 12 mm (e.g., 1 mm to 12 mm, or 1.5 mm to 6.5 mm). Correspondingly, the cross-sectional area of ​​the maximum diameter 26 of the opening is about 2.4 mm. 2 ~Approx. 38.5mm 2 The cross-sectional area of ​​the inner cavity 16 may be approximately 1.75 mm 2 ~ approx. 33.2mm 2 In some embodiments, the maximum diameter 24 of the opening 20 may be between 1.75 mm and 6.5 mm, or up to 12 mm, and the diameter 26 of the inner cavity 16 may be between 1.5 mm and 6 mm, or up to 11 mm. Correspondingly, the cross-sectional area of ​​the maximum diameter 26 of the opening is about 2.4 mm. 2 ~ approx. 33.2mm 2 and the diameter 26 of the inner cavity 16 may be about 1.75 mm 2 ~Approx. 28.3mm 2 may be also possible.

[0109] In one particular embodiment, maximum diameter 24 may include, for example, 1.75 mm or 3.5 mm, and diameter 26 may include, for example, 1.5 mm and 3 mm, respectively, such that the corresponding cross-sectional area of ​​maximum diameter 24 is approximately 2.4 mm. 2 and about 9.6 mm 2 and the corresponding cross-sectional area of ​​the diameter 26 of the inner cavity 16 is about 1.75 mm 2 and about 7.1 mm2 , resulting in a ratio of about 1.17:1.0.

[0110] Such ratios have been found to be particularly advantageous for limiting radial extension of the nerve conduit while facilitating insertion of the respective nerve ends and / or application of medical adhesive into the internal cavity 16. While embodiments may include the above configurations, it should be understood that they are not limited to the exemplary dimensions above, but may include other dimensions or ratios as long as they fall within the preferred ranges shown.

[0111] Alternatively or additionally, the ratio of the length 28 of the central portion 14 to the length 30 of the end portion 18 in the longitudinal direction may be preferably 1.2:1.0 to 15:1.0, preferably 1.2:1.0 to 12:1.0, more preferably 1.2:1.0 to 10:1.0. In some embodiments, the ratio of the length 28 of the central portion 14 to the length 30 of the end portion 18 in the longitudinal direction may be preferably 1.2:1.0 to 1.4:1.0, or 1.8:1.0 to 2.2:1.0, or 4.4:1.0 to 5.4:1.0. Furthermore, the ratio of the length 28 of the central portion 14 to the length 32 of the elongate body 12 in the longitudinal direction is preferably 0.3:1.0 to 1:1.0, for example 0.3:1.0 to 0.8:1.0. For example, the length 28 of the central portion 14 in the longitudinal direction may be 3 mm to 40 mm, preferably 4 mm to 30 mm, and more preferably 4.5 mm to 25 mm (e.g., 6.5 mm to 8.5 mm). The length 32 of the elongated body in the longitudinal direction may be 5 mm to 50 mm, preferably 6 mm to 40 mm, and more preferably 7 mm to 30 mm (e.g., 9 mm to 22 mm). The length 30 of the end portion 18 in the longitudinal direction may be 1 mm to 8 mm, and preferably 1.3 mm to 6.5 mm.

[0112] In one exemplary embodiment, the length 28 of the central portion 14 may be, for example, 8 mm, and the length 30 of each end portion 18 may be, for example, 6 mm, such that the overall length 32 of the elongate body 12 may be, for example, 20 mm, resulting in ratios between the length 28 of the central portion 14 and the length 30 of each end portion 18 of 1.33:1.0 and 0.4:1.0, and a ratio between the length 28 of the central portion 14 and the length 32 of the elongate body 12 of 0.4:1.0. Again, it should be understood that embodiments may include the above configurations but are not limited to the above exemplary dimensions, and may include other dimensions or ratios as long as they are within the preferred ranges shown.

[0113] In FIG. 3, various cross sections are shown in a side view of the nerve conduit from one outermost end of the elongate body shown in FIG. 2. The cross-sectional area 34 of the opening is therefore greater than the cross-sectional area 36 of the internal cavity. This is indicated by the corresponding different diameters. In other words, the wall of the elongate body in the region defining the maximum diameter of the opening is radially offset relative to the inner wall of the central portion defining the internal cavity. As mentioned above, the cross-sectional area of ​​the maximum diameter of the opening, or the cross-sectional area at the maximum diameter of the opening, may be, for example, about 2.4 mm. 2 ~Approx. 38.5mm 2 and the cross-sectional area of ​​the inner cavity 16 may be about 1.75 mm 2 ~ approx. 33.2mm 2 In some embodiments, the cross-sectional area of ​​the opening at or at its maximum diameter may be, for example, about 2.4 mm 2 ~ approx. 33.2mm 2 and the cross-sectional area of ​​the inner cavity 16 may be about 1.75 mm 2 ~Approx. 28.3mm 2 As indicated by dashed line 40, end portion outer surface 38 does not extend beyond central portion outer surface 40.

[0114] It will be appreciated that although FIG. 3 includes the cross-section as being circular or round, the embodiment shown in the drawing is not limited to such shapes and may be other shapes, such as ellipsoid, and the difference between the cross-section (area) 34 of the opening(s) and the cross-section (area) 36 of the inner cavity may be created by at least one radially offset extension.

[0115] Fig. 4 is a schematic perspective view of the nerve conduit 10 according to the embodiment shown in Figs. 2 and 3. From this figure, it can be seen that the openings 20 increase towards the outermost ends of the elongate body 12, creating a guide surface facilitating the insertion of the respective nerve ends into the inner cavity of the central portion 14, which is achieved by the parabolic shape of the respective end portions 18. At the same time, the gradual increase and parabolic shape of the openings 20 allow the radial extension and the length of the end portions 18 to be kept to a necessary minimum, so that the external and structural stability of the nerve conduit 10 are not significantly affected. Thus, the advantageous configuration and dimensioning of the nerve conduit 10 according to the present invention facilitates the repair of nerve damage when the nerve conduit 10 is implanted, without adversely affecting the surrounding tissue.

[0116] 5, a nerve conduit 10 according to one embodiment is shown generally with different end portions 18 and openings 20. Only one opening 20 has a larger cross-sectional area compared to the central portion 14. That is, only one opening 20 has a maximum diameter 24 that is larger than the diameter 26 of the internal cavity 16. In this manner, the nerve conduit 10 is formed as an asymmetric nerve conduit 10. In particular, this may facilitate the insertion of a thicker nerve end into the opening 20 having the larger cross-sectional area.

[0117] An embodiment of a nerve conduit 10 having opposing end portions 18 and openings 20 formed with substantially the same shape (e.g., funnel-shaped) is shown in FIG. 6. The central portion 14 and the internal cavity 16 are defined as the boundary region between the respective openings 20, as shown by the dashed lines. The boundary region may be formed, for example, by adjacent ends of the respective adjacent openings 20 or end portions 18. The boundary region may be rounded or formed to avoid significant steps between the respective end portions 18. In other words, the boundary region may be formed to provide continuous inner and outer surfaces of the walls that substantially form the nerve conduit 10. According to one embodiment, the longitudinal or axial extension of the central portion 14 is substantially negligible (e.g., close to zero or less than, for example, 10 percent of the minimum axial extension of the respective openings 20 or end portions 18) compared to the corresponding extensions of the end portions 18 or openings 20.

[0118] 7 and 8 show a nerve conduit 10 according to the invention having an elongated body with a star-shaped profile as seen in a cross-section of the end portion 18, which is rotationally symmetrical. According to this exemplary embodiment, the wall of the elongated body has six rounded bulges 41 extending the opening 20 in the radial direction and equally spaced apart from each other in the circumferential direction. The bulges 41 thus form inner and outer grooves, which are defined respectively by the circumferential width and radial extension of each bulge 41 or by the spacing between two adjacent bulges 41. According to this example, each of the six bulges 41 extends over about 20 degrees along the circumference, such that the spacing between adjacent bulges 41 extends over about 40 degrees along the circumference.

[0119] As shown, the star shape extends throughout the entire elongate body, including both the end portions 18 and the central portion 14. Moreover, according to one preferred embodiment, the star shape of the elongate body is combined with an increasing cross-section of the openings 20, including a funnel-like and / or parabolic shape at each end portion 18. Providing such a shape throughout the elongate body facilitates implantation and handling during surgery, while at the same time increasing the contact surface at each end portion 18, further improving the effectiveness of the medical adhesive in securing the respective nerve ends.

[0120] 9-11 are schematic diagrams of perspective side views of a nerve conduit 10 according to the present invention. The end portions 18 include alternative retention surfaces 42 configured to facilitate securing a medical adhesive to the respective end portions 18 on the exterior surface of the elongate body 12. In some of these embodiments, the retention surfaces 42 are depicted as being partially included on the central portions directly adjacent the respective end portions 18, although it will be understood that such extensions are merely optional.

[0121] Thus, FIG. 9 shows a nerve conduit 10 having two opposing end portions 18. Both end portions 18 have a plurality of retention surfaces 42 in the form of holes 44. The holes 44 according to this preferred embodiment are substantially circular, but slightly ellipsoidal in shape. This may occur, for example, during manufacturing. The holes 44 are formed as through holes through the wall of the elongate body. In an exemplary embodiment, the holes 44 are arranged circumferentially of the elongate body in two longitudinally spaced rows, i.e., linearly along the circumference of the elongate body within each row, with a longitudinal offset of the rows relative to each other. As shown, one row of holes 44 is provided where the central portion is directly adjacent to each end portion 18 or at the boundary between the central portion and each end portion 18. However, it will be understood that holes 44 may only be present in each end portion. Each row comprises six holes 44 equally spaced circumferentially of the elongate body, and staggered between adjacent rows.

[0122] The embodiment according to FIG. 10 is generally similar to the nerve conduit 10 according to FIG. 9. However, according to this embodiment, the retention surfaces 42 at the opposing end regions 18 are formed as grooves 46 extending helically along the outer surface of the elongate body and along the longitudinal axis defined by said elongate body. The helical shape of the grooves 46 defines substantially a filament shape extending along the outer surface of each end portion 18. The grooves 46 or filaments are formed in a mirror arrangement with respect to a mid-plane transverse to the elongate body such that they are oriented in opposite directions, i.e., extending in a clockwise and counterclockwise direction. Although the number of turns may vary, in this embodiment a groove 46 having four turns is shown. This has been found to be particularly advantageous in terms of promoting fixation of the medical adhesive while maintaining the structural stability and flexibility of the nerve conduit 10. Furthermore, the grooves 46 terminate longitudinally offset with respect to the end faces of the respective end portions 18. This is further advantageous in terms of structural stability.

[0123] As shown in more detail below at the viewing angle of Figure 12 (indicated by the dashed circle in Figure 10), the groove 46 further includes rounded edges and defines a substantially continuous undercut, which enhances the effectiveness of the medical adhesive by providing a form-fitting geometry.

[0124] FIG. 11 shows another embodiment of the retention surfaces 42 on the opposing end portions 18. As indicated by the corresponding arrows, each end portion 18 includes a plurality of grooves 46 extending in opposite circumferential directions and intersecting each other. According to this embodiment, each end portion 18 is provided with seven grooves 46 in each circumferential direction, and the number of grooves 46 is equal for each circumferential direction. As shown in FIG. 11, the grooves 46 in each circumferential direction together make a half-turn helical rotation along the longitudinal axis defined by the elongated body to create a diamond or lozenge shape on the outer surface of each end portion 18, which also resembles the surface of a pineapple. As a result, a plurality of retention surfaces 42 with multiple edges can be created. This can be advantageous for fixing a medical adhesive to each end portion 18.

[0125] FIG. 12 shows a schematic diagram of the undercut defined by the groove 46 in longitudinal section according to the dashed line shown in FIG. 10. As shown, the top outer surface of the groove 46 and the bottom surface of the groove 46 correspond to an outer radius 50 and an inner radius 48, respectively, and define the depth of the groove. They are rounded to reduce stresses in the material having the groove 46 with sharp edges. Furthermore, the top surface extends longitudinally above the bottom surface. This forms an angle 52 of the groove 46 and a corresponding undercut in the bottom surface, as shown by the dashed line. The angle 52 (preferably about 75 degrees) and the corresponding undercut allow for a form fit or secure fixation between the applied medical adhesive and the respective end portion 18 in the radial direction. This further enhances the effectiveness of the medical adhesive in fixing the damaged nerve end to the respective end portion 18.

[0126] It will be apparent to those skilled in the art that these embodiments and items are merely examples of multiple possibilities. Therefore, the embodiments shown herein should not be understood as limiting these features and configurations. Any possible combination and configuration of the described features can be selected according to the scope of the present invention.

[0127] The present invention is further illustrated in the following sections. 1. A nerve conduit (10) comprising an elongate body (12), The elongated body (12) a central portion (14) defining an internal cavity (16); a plurality of end portions (18) defining respective openings (20) into the internal cavity (16) and disposed adjacent the central portion (14) at longitudinally opposed ends of the elongated body (12); Equipped with A nerve conduit (10), wherein the cross-sectional area of ​​at least one opening (20) is greater than the cross-sectional area of ​​the internal cavity (16) of the central portion (14).

[0128] 2. The central portion (14) is formed as a substantially tubular shape, 2. The nerve conduit of item 1, wherein the elongate body (12) comprises two end portions (18).

[0129] 3. 3. The nerve conduit (10) of claim 1 or 2, wherein the plurality of openings (20) and the internal cavity (16) define a single lumen or a continuous through hole.

[0130] 4. The nerve conduit (10) according to any one of items 1 to 3, wherein the cross-sectional area of ​​each of the multiple openings (20) is greater than the cross-sectional area of ​​the internal cavity (16), or the cross-sectional area of ​​the opening (20) of only one end portion (18) is greater than the cross-sectional area of ​​the internal cavity (16).

[0131] 5. 5. The nerve conduit (10) according to any one of items 1 to 4, wherein the cross-sectional area of ​​at least one of the openings (20) increases with increasing longitudinal distance from the central portion (14).

[0132] 6. at least one of the end portions (18) and the corresponding openings (20) are rotationally symmetrical about a longitudinal axis defined by the elongated body (12); 6. The nerve conduit (10) according to item 5, wherein the shape is substantially U-shaped, sigmoidal, conical, concave, funnel-shaped, or parabolic.

[0133] 7. The nerve conduit (10) according to any one of items 1 to 6, wherein a plurality of the end portions (18) are formed in the same manner.

[0134] 8. A nerve conduit (10) as described in any one of items 1 to 7, wherein the inner cavity (16) and the plurality of openings (20) are formed by a single wall (22) of the elongate body (12) that defines the inner and outer diameters of the elongate body (12).

[0135] 9. 9. The nerve conduit (10) of item 8, wherein the wall (22) has a substantially continuous thickness circumferentially and longitudinally along the elongate body (12).

[0136] 10. 10. The nerve conduit (10) of item 8 or 9, wherein the inner diameter and the outer diameter of the central portion (14) are substantially continuous in the longitudinal direction of the elongate body (12).

[0137] 11. The nerve conduit (10) according to any one of items 8 to 10, wherein the diameter of at least one of the openings (20) increases with increasing longitudinal distance from the central portion (14).

[0138] 12. 12. The nerve conduit (10) according to item 11, wherein the ratio of the maximum diameter (24) of at least one of the openings (20) to the diameter (26) of the internal cavity (16) is 1.05:1.0 to 1.5:1.0, preferably 1.05:1.0 to 1.2:1.0.

[0139] 13. 13. The nerve conduit (10) of claim 11 or 12, wherein a maximum diameter (24) of at least one of the openings is smaller than or corresponds to the outer diameter of the central portion (14).

[0140] 14. A nerve conduit (10) as described in any one of items 1 to 13, wherein the outer surfaces (38) of the multiple end portions (18) extending from the central portion (14) are aligned with the outer surface (40) of the central portion (14) and / or are free of steps or edges relative to the outer surface (40) of the central portion (14).

[0141] 15. 15. The nerve conduit (10) according to any one of items 1 to 14, wherein the ratio of the length (28) of the central portion (14) to the length (30) of the end portion (18) in the longitudinal direction is 1.2:1.0 to 15:1.0, preferably 1.2:1.0 to 12:1.0, and more preferably 1.2:1.0 to 10:1.0.

[0142] 16. 16. The nerve conduit (10) according to any one of items 1 to 15, wherein the ratio of the length (28) of the central portion (14) to the length (30) of the end portion (18) in the longitudinal direction is 1.2:1.0 to 6.0:1.0, preferably 1.2:1.0 to 1.4:1.0, or 1.8:1.0 to 2.2:1.0, or 4.4:1.0 to 5.4:1.0.

[0143] 17. 17. The nerve conduit (10) according to any one of items 1 to 16, wherein the ratio of the length (28) of the central portion (14) to the length (32) of the elongate body (12) in the longitudinal direction is 0.3:1.0 to 1:1.0, for example, 0.3:1.0 to 0.8:1.0.

[0144] 18. The nerve conduit (10) according to any one of items 1 to 17, wherein the length (28) of the central portion (14) in the longitudinal direction is 3 mm to 40 mm, preferably 4 mm to 30 mm, and more preferably 4.5 mm to 25 mm.

[0145] 19. The nerve conduit (10) according to any one of items 1 to 18, wherein the length (32) of the elongated body (12) in the longitudinal direction is 5 mm to 50 mm, preferably 6 mm to 40 mm, and more preferably 7 mm to 30 mm.

[0146] 20. 20. The nerve conduit (10) according to any one of items 1 to 19, wherein the length (30) of the end portion (18) in the longitudinal direction is 1 mm to 8 mm, and preferably 1.3 mm to 6.5 mm.

[0147] twenty one. The length (28) of the central portion (14) in the longitudinal direction is 5 mm to 10 mm, preferably 6.5 mm to 8.5 mm. the length (32) of the elongate body (12) in the longitudinal direction is between 7 mm and 25 mm, preferably between 9 mm and 22 mm; and / or 21. The nerve conduit (10) according to any one of items 1 to 20, wherein the length (30) of the end portion (18) in the longitudinal direction is 1 mm to 8 mm, and preferably 1.3 mm to 6.5 mm.

[0148] twenty two. 22. The nerve conduit (10) according to any one of items 1 to 21, wherein the diameter (26) of the inner cavity (16) is 1 mm to 15 mm, preferably 1 mm to 12 mm.

[0149] twenty three. The nerve conduit (10) according to any one of items 1 to 22, wherein the maximum diameter (24) of at least one of the openings (20) is between 1 mm and 15 mm, preferably between 1.5 mm and 13 mm, and more preferably between 1.75 mm and 7 mm.

[0150] twenty four. the diameter (26) of the inner cavity (16) is between 1 mm and 12 mm, preferably between 1.5 mm and 6.5 mm; and / or 24. The nerve conduit (10) according to any one of items 1 to 23, wherein the maximum diameter (24) of at least one of the openings (20) is between 1.5 mm and 11 mm, preferably between 1.75 mm and 6.5 mm.

[0151] twenty five. 25. The nerve conduit (10) of any one of items 1 to 24, wherein the elongate body (12) is formed from a biocompatible material, an inert material, a bioimplantable material, and / or a biodegradable material.

[0152] 26. 26. The nerve conduit (10) of any one of claims 1 to 25, wherein the elongate body (12) is formed from a polymeric material, preferably an elastomer.

[0153] 27. 27. The nerve conduit (10) of any one of items 1 to 26, wherein the central portion (14) and the plurality of end portions (18) are integrally formed or formed from a single piece.

[0154] 28. the elongated body (12) is formed from polymerized and / or crosslinked polymer units that include ester group components and acid ester group components; The ester group component is preferably a polyol, 28. The nerve conduit (10) according to any one of items 1 to 27, wherein the acidic ester group component is preferably a polyacid.

[0155] 29. 29. The nerve conduit (10) of any one of items 1 to 28, formed by a 3D printing process.

[0156] 30. 30. Use of a nerve conduit (10) according to any one of items 1 to 29 for repairing, supporting and / or guiding nerve tissue, in particular for repairing peripheral nerve damage.

[0157] 31. 31. Use of a nerve conduit (10) according to item 30 in combination with a medical adhesive.

[0158] 32. 1. A method for treating peripheral nerve injury, comprising: - providing a nerve conduit (10) according to any one of claims 1 to 31; - inserting one end of an injured nerve into the nerve conduit (10) through an opening (20) of the central portion (14) having a cross-sectional area larger than the internal cavity (16); - inserting another end of the damaged nerve through an opening (20) in an end portion (18) at opposite longitudinal ends of the elongate body (12); - fixing a plurality of said injured nerve ends within said elongate body (12); A method comprising:

[0159] 27. 33. The method according to claim 32, wherein the step of fixing the damaged nerve ends is performed by applying a medical adhesive to the outside of the internal cavity (16) and / or through at least one of the plurality of openings (20) into the plurality of openings (20) and / or around the plurality of openings (20).

[0160] (List of reference numbers) 10 Nerve conduit 12 Long and thin body 14 Central part 16 Inner Cavity 18 End section 20 Opening 22 Wall 24 Maximum opening diameter 26 Diameter of inner cavity 28 Center section length 30 End length 32 Length of elongated body 34 Cross section of opening (area) 36 Cross section of inner cavity (area) 38 Outer surface of end portion 40 Outer surface of central section 41 Bulge 42 Retention surface (retention surface) 44 holes 46 Groove 48 Inner Radius 50 outer radius 52 angle

Claims

1. A nerve conduit (10) comprising an elongate body (12), The elongated body (12) a central portion (14) defining an internal cavity (16); a plurality of end portions (18) defining respective openings (20) into the internal cavity (16) and disposed adjacent the central portion (14) at longitudinally opposed ends of the elongated body (12); Equipped with a cross-sectional area of ​​at least one opening (20) greater than a cross-sectional area of ​​the inner cavity (16) of the central portion (14); a cross-sectional area of ​​at least one of said openings (20) increases with longitudinal distance from said central portion (14); at least one of said end portions (18) and said corresponding openings (20) are rotationally symmetrical about a longitudinal axis defined by said elongate body (12); The rotationally symmetric shape of the nerve conduit (10) is substantially funnel-shaped, or paraboloid-shaped.

2. The nerve conduit (10) of claim 1 , wherein a plurality of said end portions (18) are similarly configured.

3. The nerve conduit (10) of claim 1 or 2, wherein a diameter of at least one of the openings (20) increases with longitudinal distance from the central portion (14).

4. The nerve conduit (10) of claim 1 or 2, wherein the ratio of the maximum diameter (24) of at least one of the openings (20) to the diameter (26) of the internal cavity (16) is between 1.05:1.0 and 1.5:1.

0.

5. 3. The nerve conduit (10) of claim 1 or 2, wherein the ratio of the length (28) of the central portion (14) to the length (30) of the end portions (18) in the longitudinal direction is from 1.2:1.0 to 15:1.

0.

6. The nerve conduit (10) of claim 1 or 2, wherein the length (28) of the central portion (14) in the longitudinal direction is between 3 mm and 40 mm.

7. The nerve conduit (10) of claim 1 or 2, wherein the length (30) of the end portion (18) in the longitudinal direction is between 1 mm and 8 mm.

8. a cross-sectional area of ​​at least one of said openings (20) increases with longitudinal distance from said central portion (14); At least one of the end portions (18) and the corresponding opening (20) are formed as a rotationally symmetric funnel and / or paraboloid along a longitudinal axis defined by the elongated body (12); the internal cavity (16) and the plurality of openings (20) are formed by a single wall (22) of the elongated body (12) that defines an inner diameter and an outer diameter of the elongated body (12), the single wall (22) having a substantially continuous thickness along a circumferential direction and a longitudinal direction of the elongated body (12); The nerve conduit (10) of claim 1 or 2, wherein the inner diameter and the outer diameter of the central portion (14) are substantially continuous along the length of the elongate body (12).

9. a cross-sectional area of ​​each of the plurality of openings (20) is greater than a cross-sectional area of ​​the inner cavity (16) and increases with increasing longitudinal distance from the central portion (14); At least one of the end portions (18) and the corresponding opening (20) are formed as a rotationally symmetric funnel and / or paraboloid along a longitudinal axis defined by the elongated body (12); The nerve conduit (10) of claim 1 or 2, wherein the internal cavity (16) and the plurality of openings (20) are formed by a single wall (22) of the elongate body (12) having a substantially continuous thickness along the circumferential and longitudinal directions of the elongate body (12).

10. At least one of the plurality of end portions (18) includes one or more retention surfaces (42) on an exterior surface of the elongate body (12); The nerve conduit (10) of claim 1 or 2, wherein the one or more retention surfaces (42) are configured to secure a medical adhesive to the respective end portion (18).

11. The nerve conduit (10) of claim 10, wherein one or more of the retention surfaces (42) of each end portion (18) are formed as at least one groove (46) extending in a spiral direction along a longitudinal axis defined by the elongate body (12).

12. The nerve conduit (10) of claim 11, wherein at least one of the grooves (46) has a radial depth that varies as the cross-sectional area of ​​at least one of the openings (20) increases longitudinally away from the central portion (14).

13. The at least one groove (46) is at least two grooves (46) extending in circumferential directions opposite to each other and intersecting each other, The nerve conduit (10) of claim 11, wherein each groove (46) extends between 0.5 and 5 revolutions about the longitudinal axis.

14. The nerve conduit (10) of claim 1 or 2, wherein the elongate body (12) is formed from a biocompatible, inert, bioimplantable, and / or biodegradable material.

15. The nerve conduit (10) of claim 1 or 2, wherein the elongate body (12) is formed from a polymer-based material.

Images