Expandable bone implant for veterinary orthopedic surgery, orthopedic system and method for manufacturing the implant

Abstract

The present invention relates to an expandable bone implant for veterinary orthopedic surgery, for restoring volume and / or geometry of a bone, an orthopedic system and a method for manufacturing the implant, the implant comprising a hollow body formed by a sheet (10) made of biocompatible metal alloy, closed on itself in a sealed manner between proximal and distal ends, having, at least in the folded configuration, a plurality of pairs of folds, each pair comprising an antiform fold, referred to as a convex fold, and optionally a synform fold, referred to as a concave fold, the folds being laid one on top of the other in the folded configuration such that the surfaces present between each of the convex and concave folds are wound around the longitudinal axis (L), the sheet (10) being plastically deformable so as to allow expansion of the implant from the folded configuration to the deployed configuration upon injection of a fluid into the implant (1).

Description

Description Title of the invention: Expandable bone implant for veterinary orthopedic surgery, Orthopedic system and Implant manufacturing method

[0001] This application relates to the field of surgery, in particular veterinary orthopedic surgery, and specifically to the treatment of collapsed bone structures by restoring the volume (or straightening) of these structures, or at least restoring their geometry. This application specifically concerns an implant and its manufacturing process, as well as a system for restoring bone structure, particularly in the spine, for the treatment (often called "reduction") of compression fractures, especially vertebral compression fractures (VCF).

[0002] In this field, the problem of restoring the volume of collapsed bone structure is well known, and the literature abounds with solutions using expandable implants capable of moving from a folded to a deployed configuration to restore the height of the bone structure, preferably in combination with an injection of bone replacement cement, also called bone cement. Many cements are known, and they all have the advantage of being injectable in a liquid or viscous state for a certain period, then hardening (by polymerization) within the bone structure to stabilize it.

[0003] A major problem in this field concerns implant expansion to restore height to damaged bone tissue. Numerous solutions are known from the prior art, such as patent applications EP3086729, US11540926, EP3747385, EP2572680, EP3958752, EP2693967, EP2405835, US9579130, EP4216836, WO2023122005, WO2022162418, EP3843668, and US10945861, but these solutions present various problems related to the difficulty of handling during deployment, as well as stability and reliability issues once deployed. Moreover, these known solutions are generally accompanied by an injection of bone cement but provide no teaching regarding cement leakage outside the implant, whereas such leakage can be detrimental to surrounding tissues, or even the entire organism if the chemicals of the cement invade the bloodstream.Indeed, cement generally contains one or more polymerizable chemical substances, for example poly(methyl methacrylate) (PMMA), and possibly additives. Furthermore, the temperature reached during cement polymerization is not harmless, as it is generally above 60°C.

[0004] It is known from the prior art, notably from documents EP1308134, US9510877, US8936627 or EP2467099, of devices for straightening and stabilizing (or reducing bone fractures), particularly of the spine in the form of stents, or in the form of balloons or Porous inflatable bags, as described in documents EP1408888 or EP1379185, may be equipped with support plates, as in document US20060100706. Many documents propose this type of stent, that is, a deformable endoprosthesis similar to endoprostheses, expanders, or vascular stents, which are generally in the form of a tubular mesh body, most often metallic, and deformable by the introduction of an inflatable balloon to expand the body by separating the mesh. The balloon is then removed to allow the injection of cement, which hardens and thus forms a straightening and stabilizing structure. However, these devices have the disadvantage of requiring a two-stage implantation: inflation of the balloon followed by cement injection. This slows down and complicates the operation and also presents a risk of device collapse between balloon deflation and cement filling of the stent.On the other hand, these solutions have the disadvantage of not addressing the major problem of cement leaks.

[0005] It is also known, notably from documents EP1938765, EP2351539, and WO200434924, that solutions use mesh-structure implants made of shape-memory metal, which is constrained into a folded shape for insertion into bone tissue and is capable of spontaneously expanding when the constraint is released and / or under the effect of heat. These solutions have the disadvantage of requiring expensive alloys and complex manufacturing to achieve adequate shape memory suitable for the intended implantation. This leads to increased costs by multiplying the number of different implants needed to cover various pathological cases, particularly due to the extent of deformation the shape-memory material is capable of. Furthermore, the force exerted by the metal returning to its unconstrained shape is often insufficient to properly straighten the collapsed bone structure, or at least is limiting in its ability to do so.On the other hand, these solutions also have the disadvantage of not addressing the major problem of cement leaks.

[0006] Prior art, notably documents EP2405835, US9579130, EP2572680, and EP1956990, also describe solutions using expandable implants with a lever mechanism, similar to a car jack, to restore bone structure to a predetermined height. These solutions have the advantage of not risking collapse, unlike stents deployed by a balloon that is removed before cement injection. However, they also have the disadvantage of requiring two implantation stages and a limited surface area for exerting expansion force on the bone tissue, especially compared to stents. Furthermore, they are expensive and do not address the major problem of cement leakage.

[0007] The problem of cement leakage has already been identified, notably in documents EP1408888, EP1509175, and W0200394805, which express the potential of a deformable, low-permeability, or impermeable implant to limit or prevent cement leakage. These documents consider numerous solutions for an expandable implant, made of metal or polymer, which could be either soft and flexible like a membrane or a The material, possibly elastic, could be semi-rigid ("conformable") or rigid, or made of shape-memory material, with a continuous or fenestrated (i.e., meshed) wall, and could be porous or non-porous. However, all these hypotheses described in these documents primarily define possible treatment methods and objectives to be achieved, without providing any real guidance regarding the technical characteristics or structural arrangement of the implants, nor on how to obtain such implants and thus implement these methods. These proposals therefore present a major problem of technical feasibility.

[0008] On the other hand, a problem not identified in the prior art concerns the cement injection site and the distribution of forces exerted on the bone tissues to straighten them. Indeed, the impermeability of an implant prevents cement leakage, but the nature of the impermeable membrane and its technical characteristics, such as its physicochemical and mechanical properties, influence its ability to expand without rupturing and to straighten the bone structure. Thus, an elastic membrane has the disadvantage of deforming excessively in areas of low density and therefore has a limited capacity to restore height, with the added risk of rupture where its maximum elasticity is exceeded due to this uncontrolled deformation. A semi-rigid membrane is therefore preferable, but this deformation problem also implies a problem with the implant's shape, both in its folded and, especially, deployed configuration.Indeed, the shape of the deployed implant defines the cement injection site, and controlling this site is crucial for distributing the forces necessary to fill low-density areas while simultaneously straightening the structure (particularly vertically), thus impacting the success of the operation. Therefore, it is understandable that providing an implant that addresses all these issues presents a challenge in terms of technical feasibility and, consequently, manufacturing.

[0009] Other recurring problems in orthopedic surgery concern invasiveness (i.e., the goal of making the smallest possible incision and lesions) but also the deployment ratio in order to obtain a deployed implant that fills the largest possible volume while being inserted through the smallest possible opening. Furthermore, this deployment ratio will impact the distribution of forces used to straighten the vertebrae: if the implant is too deformable, the pressure from injecting the cement will deform the pocket instead of restoring the height.

[0010] A problem complementary to that of deployment concerns folding, which is generally not possible with anterior art implants. Controlling folding allows for control of deployment and therefore of the injection site, with homogeneous distribution of cement and pressure to fill the space created by the collapse. Perfect homothety adapts to the fracture, respecting the shape of the bone within the fracture.

[0011] In this context, it is understandable that a technical problem persists in the field concerning the restoration of bone structure (straightening or reducing fractures or increasing volume after collapse) using an expandable (deployable) implant which be capable of expanding collapsed bone tissue and sufficiently impermeable to prevent or limit cement leakage outside the implant with control of the injection site.

[0012] Finally, a major problem that persists in the field concerns the technical feasibility of manufacturing the implants proposed in the prior art. For example, document W0200394805 describes numerous methods for administering substances, including bone cement, with many variations considered for an expandable implant, made of metal or polymer. This implant could be either soft and flexible like a membrane or tissue, semi-conformable or rigid, or made of shape-memory material, with a continuous or fenestrated (i.e., meshed) wall, and could be porous or non-porous. However, this document only describes possible treatment methods but provides no guidance regarding the technical characteristics or structural design of these numerous hypothetical implants used in these proposed methods, nor on how to obtain such implants and thus actually implement these methods.These proposals therefore present a major problem of technical feasibility and define goals to be achieved rather than means of achieving them. Furthermore, even though many objectives have been detailed in the literature, many implants proposed to achieve these objectives have never materialized due to manufacturing problems. To address the manufacturing problem, it is necessary to consider the issues related to the desire to compact / fold a "bag" (balloon / pouch) made of rigid and waterproof material in order to: - pass through a cylindrical conduit; - to make it possible to expand the pocket without breaking it, despite the rigidity and the desired difference in volume between the folded volume and the deployed volume; - Control the volume and distribution of expansion forces on the bone.

[0013] In this context, one aim of the present invention is to overcome at least some of the drawbacks of the prior art by offering a reliable and easy-to-handle and implantable bone restoration implant for collapsed bone structures.

[0014] This goal is achieved by an expandable bone implant for veterinary orthopedic surgery for restoring the volume and / or geometry of a bone, through expansion between a folded and an deployed configuration, said implant comprising a hollow body extending along a longitudinal axis between a proximal end connectable to an implantation instrument to hold the implant and a distal end intended to be inserted first into the bone, said implant being characterized in that: - the wall of said hollow body is formed by a sheet of biocompatible metal alloy, sealed tightly on itself, between said proximal and distal ends; - said sheet presents, at least in the folded configuration, a plurality of pairs of folds, each pair comprising an antiform fold, called convex, and a synform fold, called concave, said folds being laid one on top of the other in the folded configuration so that the surfaces present between each of said convex and concave folds are rolled around the longitudinal axis, - said proximal end comprises a sleeve or ring securely attached, in a watertight manner, to the flattened and rolled folds of said sheet over the entire periphery of the proximal end, the opening through said sleeve providing an entry into the hollow body of the implant, - said distal end comprises a socket closing the distal end and securely attached, in a hermetic manner, to the flattened and rolled folds of said sheet over the entire periphery of the distal end of said hollow body - said sheet being plastically deformable to allow the expansion of the implant from the folded configuration to the deployed configuration, when a fluid is injected into the implant through said sleeve.

[0015] According to another peculiarity, the distance between a synform fold and the next antiform fold is longer than the distance between an antiform fold and the synform fold, to facilitate the rolling of the folds around the longitudinal axis.

[0016] According to another feature, the implant has, in the deployed position, a median portion between its two ends which has a generalized cylindrical shape, with a possible and at least partial persistence of said folds, said median portion extending, on the side of the proximal end, by a truncated conical portion connecting the median portion to said sleeve and, on the side of the proximal end, by a truncated conical portion connecting the median portion to said socket, the truncated conical portions having a permanent persistence of at least a part of the folds lying down and rolled up near the proximal and distal ends.

[0017] According to another peculiarity, the said sheet is also plastically deformable from the folded configuration to the deployed configuration, notably thanks to the persistence of the horizontal and rolled folds at the proximal and distal ends, to allow a reversibility of the expansion.

[0018] According to another feature, said sleeve is able to cooperate with the distal end of an implantation instrument passing through said implant via the opening of the proximal end, for example by means of at least one housing and / or protrusion complementary to at least one protrusion and / or housing of said instrument which includes a hollow tube able to pass through said sleeve and whose internal conduit opens into said hollow body of the implant through at least one opening allowing the injection of said fluid into the implant.

[0019] According to another feature, said sheet is secured to said sleeve at the proximal end by a weld fixing the proximal end of the folds lying and rolled against the outer wall of said sleeve and / or secured to the base at the distal end by a weld fixing the distal end of the folds lying and rolled against the outer wall of said sleeve.

[0020] According to another feature, said sheet is compressed around the ring at the proximal end and / or around the base at the distal end by a second ring, called a compression ring, keeping the folds lying flat and rolled against the outer wall of said sleeve and / or of said socket.

[0021] According to another characteristic, the folds are, at least in the folded configuration, parallel to the longitudinal axis.

[0022] According to another characteristic, the outside diameter of said socket and / or said ring is less than or equal to the maximum folded diameter of the implant.

[0023] According to another characteristic, the number of pairs of folds is between 3 and 16, generally 4 to 12, preferably around 8.

[0024] According to another peculiarity, the sheet is closed on itself by means of two folds in opposite directions (synform and antiform), made on the two opposite edges of the sheet, so as to fit together and form a longitudinal closure and give the sheet a generalized cylindrical shape, at least before the making of folds and their rolling.

[0025] According to another characteristic, the sheet has a thickness of between 3 and 100 microns, generally between 6 and 50 and preferably 10 and 30 microns.

[0026] Another distinctive feature is that the sheet is made of titanium alloy.

[0027] According to another feature, the sheet also has at least one pair of folds (a synform fold and an antiform fold) with an axis not parallel to the longitudinal axis, preferably perpendicular for an equally lengthwise expansion of the implant or oblique for a curved expansion of the implant.

[0028] Another distinctive feature is that the distance between the folds varies along the circumference of the implant, so that the shape of the implant in its deployed configuration is curved or asymmetrical.

[0029] According to another characteristic, the folded diameter is less than the unfolded diameter by a factor of between 3 and 20, generally 3 to 8, preferably 4 to 7.

[0030] Another objective of this application is to address at least some of the drawbacks of the previous art by proposing a surgical intervention system that is easy to use and allows for effective stabilization of bone tissue.

[0031] This goal is achieved by an orthopedic treatment system for damaged bone tissue comprising a bone replacement cement and at least one instrument for implanting and injecting cement into the implant, characterized in that it comprises an implant according to one of the preceding claims.

[0032] According to another feature, the cement implantation and injection instrument includes means for controlling the pressure and / or suction of the cement to fold the implant into a folded configuration if necessary.

[0033] According to another peculiarity, the implantation instrument is distinct but complementary to the injection instrument, whose cement injection channel passes through a channel inside the stem of the implant instrument, which holds the proximal end of the implant by means of its distal end.

[0034] Another objective of the present application is to overcome at least some of the drawbacks of the prior art by proposing a method for manufacturing an implant according to the invention.

[0035] This objective is achieved by a method for manufacturing an implant according to one of the preceding claims, characterized in that it comprises: The sheet is closed upon itself and welded to form a generalized cylinder. Insertion of the closed sheet onto a generalized cylindrical matrix having a star-shaped base, the number of points of the star defining the number of pairs of folds of said sheet of said implant. Compression of the closed sheet between said matrix and a plurality of protruding elements of shape complementary to the hollows between the points of the star. Rolling the folds of said sheet around the longitudinal axis. Securing said sheet to said socket and ring.

[0036] Other features and advantages of the present invention will become clearer upon reading the description of various embodiments below, made with reference to the accompanying drawings, in which: Figures 1: Figure 1A represents a perspective view of an expandable implant in its folded configuration, according to certain embodiments and Figure IB represents a perspective view of the same implant in its deployed configuration; Figures 2: Figure 2A represents a perspective view of an expandable implant in deployed configuration and held by an implantation instrument, according to certain embodiments, Figure 2B represents a perspective view of this same implant with a section showing the implantation instrument inside the implant and Figure 2C represents the same view as Figure 2B but for a double-leaf implant; Figures 3: Figure 3A represents a perspective view of an expandable implant in a semi-deployed configuration, according to certain embodiments, Figure 3B represents a perspective view of a sheet used for the manufacture of an expandable implant according to certain embodiments in a semi-folded configuration and Figure 3C represents a perspective view of this same sheet in a folded configuration; Figures 4: Figure 4A represents a perspective view of an expandable implant in folded configuration with weld lines at the proximal and distal ends and Figure 4B represents an enlargement of Figure 4A at the distal end; Figures 5: Figure 5A represents a perspective view of a tool for guiding the folding of a sheet of an expandable implant according to certain embodiments guided by means of a guide tube and Figure 5B represents a profile view of this same tool with the folded sheet, the enlargements 5C and 5D representing profile views of the cover of the sheet at the level of its closure according to two different embodiment examples; Figures 6: Figure 6 shows a perspective view of a pre-folding tool for sheets for expandable implant according to certain embodiments, using a pre-folding plate; Figures 7: Figure 7A represents an enlargement of Figure 6, Figures 7B, 7C and 7D represent top views of different embodiments of the pre-bending tool with a sheet of the implant slid around a star-shaped rod of the pre-bending tool; Figures 8: Figure 8A shows a perspective view of a sheet pre-folded using a star-shaped rod such as that in Figure 7D, and Figure 8B shows the same sheet folded over itself, according to certain embodiments; Figures 9: Figure 9A represents a top view of a vertebra in which an implant is implanted according to various embodiments, Figure 9B represents a perspective view of the implantation of an anterior-art implant in a vertebra and Figure 9C represents a perspective view of the implantation of an implant according to certain embodiments of the present invention; Figures 10: Figures 10A, 10B and 10C represent profile views of vertebrae that have suffered vertebral compression fractures (VCF) at the anterior medial and posterior levels respectively.

[0037] This application relates to an implant and an orthopedic surgical system for the treatment of fractured bones and bone tissue in general, as well as a method for manufacturing the implant. The bone implant is preferably a spinal implant, and in particular a vertebral or even intravertebral implant, but other uses are conceivable elsewhere in the spine (intervertebral spines) or in other bony structures where it is necessary to fill a gap resulting from a fracture (the causes of which can be varied, although they generally involve a decrease in bone density). Thus, vertebral compression fractures (VCFs) are a preferred application but are not the only ones that can be treated with the present invention, and those skilled in the art will appreciate the possibilities offered without needing further detail here.Other bones that could be affected include the femur or humerus (head), for example, in cases where there is a risk of collapse. This application relates to an implant and a veterinary orthopedic surgical system for the treatment of fractured bones and bone tissue in general, as well as a method for manufacturing the implant. The bone implant is preferably a spinal implant, and in particular a vertebral or even intravertebral implant, but other uses are conceivable elsewhere in the spine (intervertebral spines) or in other bony structures where it is necessary to fill a gap resulting from a fracture (the causes of which can be varied, although they generally involve a decrease in bone density).Thus, vertebral compression fractures (VCFs) are a favorite application, but they are not the only ones that can be treated with the present invention, and those skilled in the art will appreciate the possibilities offered without needing further detail here. Other bones that can be treated include the femur or humerus (head), for example, in cases of risk of collapse. In the veterinary field, it is known that animals have bone densities that are sometimes very different from those of humans, and especially highly variable depending on the species and even between breeds or animals within the same species, particularly for dogs, whose physical properties vary enormously from one breed to another. For example, dachshunds and similar breeds have long (tall) but narrow vertebrae compared to other breeds.It is therefore useful to have expandable implants that allow for significant vertical expansion while maintaining a reduced length, and it is clearly necessary to consider the differences in bone shape and size among different species to effectively adapt therapy with suitable implants. Furthermore, some... Species like the cat have a very rigid cortical bone but more flexible spongy tissue than other species. Therefore, it is also necessary to consider the nature of the bone tissue. Finally, another notable example concerns horses, whose bones, particularly the vertebrae, have a specific anatomical shape and sometimes bear a significant load. Depending on the activity (for example, sport) and the animal's conformation, bone density varies, and implants must be adapted to allow for expansion while also supporting the loads. Thus, for a horse, it may be necessary to have implants with more load-bearing arms (a minimum of 3 or 4) than for other species (where 2 support arms are sometimes sufficient). In the absence of support arms, the implant must then have sufficient mechanical resistance, achieved through a capacity to withstand higher cement pressure than in other cases.Furthermore, the tibial plateau is frequently subjected to crushing, and the implants or systems of this application are useful for restoring height in all types of bone crushing or collapse, for example, in the distal humerus or femur. Moreover, as taught, for example, in document EP2921142, it is possible to use expandable implants as bone anchors, and such use is also possible for implants like those of this application. In this case, the implants will be extended at their proximal end by an elongated body onto which another orthopedic implant of a different type or a surgical device for fixing other elements can be attached.However, in the case of use as a bone anchor in a vascularized structure, such as a humeral or femoral head, the size of the implant should preferably be limited relative to the bone structure to preserve vascularization and promote bone healing.

[0038] Some embodiments involve injecting a fluid (e.g., "bone cement," generally based on a polymer such as PMMA, which is well-known to those skilled in the art, so no details about the cement will be provided here). Once positioned, the implant can be stabilized by such a cement injection. However, since cement leakage is a major problem in this field, various embodiments propose containing the cement within a sealed envelope. The volume of this envelope after injection can be controlled by its structure and material, depending on the injected pressure (and the configuration of the bone tissue, preferably assessed beforehand, as is common practice in this field). The seal is, of course, relative, and this term is not a limiting one, since the level of sealing is actually adapted to the viscosity of the cement at the time of injection.Certain embodiments allow, in particular, for homothetic swelling of the envelope thanks to the (relative) flexibility of the biocompatible metallic sheet (10). This material is generally a titanium alloy obtained in the form of a very thin sheet, preferably by lamination for a controlled surface finish and thickness, in particular a thickness between 3 and 100 microns, generally between 6 and 50, and preferably between 10 and 30 microns. Generally speaking, the present invention uses at least one sheet (10) of biocompatible metal or a biocompatible metal alloy, such as titanium or its alloys, particularly with nickel or other metals, but also nitinol or steel. Stainless steel or their alloys. Recent techniques are used to obtain very thin sheets of such metals, particularly those less than 50 or even 40 µm thick. This allows for relatively flexible and elastic sheets, but more importantly, sheets whose plastic deformation can be used reversibly without reaching their tearing limit, by creating folds arranged longitudinally on the implant. In particular, it is possible to design a maximum deployed volume that exceeds the volume required for the desired applications, ensuring that this limit is never reached and allowing the implant to be folded and redeployed, even repeatedly (for example, in case of implant misalignment), without risk of uncontrolled tearing and leakage.Thus, thanks to this type of sheet and the configuration of their interlocking folds, it is possible to obtain expansion ratios, between the folded volume and the deployed volume, ranging from 2 to 20, or even 30. It is also possible to control the shape of the implant in its deployed configuration, depending on the arrangement of the folds, much like origami. Finally, although a primary goal here is to prevent cement leakage, it can sometimes be advantageous to control the cement's release from the implant, so that we no longer speak of leakage but of controlled release, for example, to allow adhesion to certain surrounding structures (generally bone structures). Similarly, since the injected fluid is not necessarily cement (or at least not the fluid that would exit the implant), it can actually be beneficial to administer molecules through such a controlled release of this fluid.Thus, various embodiments incorporate a certain degree of porosity in the sheets (10), at least in certain portions of the implant, for example, through controlled microscopic holes of controlled size, number, and density. In any case, this type of sheet is capable of reversible plastic deformation a number of times sufficient for the intended application, since it notably offers the possibility of retracting the envelope formed by the sheet in case of a problem (biocompatibility and tear resistance). Indeed, in general, the cement dosage control allows monitoring of the fifteen minutes of polymerization during which it is possible to retract the envelope and aspirate the cement. Furthermore, through cement injection and the swelling of the envelope, the implant fills the spaces in the damaged tissues according to the compressive forces and bone resistance relative to the hydraulic pressure provided during the cement injection.Starting with such a sheet, it is necessary to obtain a closed structure, which requires folding the sheet over itself and locking it in position. To achieve this, welding (or gluing or brazing, these terms are not exhaustive) can be performed between two overlapping edges or on edges with interlocking folds, to facilitate and strengthen the weld. Some designs therefore incorporate external welding for closure, which is simplified and made stronger by layering the sheets at these complementary folds.

[0039] Various embodiments allow for obtaining an expandable implant with very small dimensions in its folded configuration while ensuring a satisfactory volume in its deployed configuration. Thus, the passage necessary for the introduction of the implants of the present de- The folded diameter or volume is generally smaller than that of known implants, while the expansion is greater than that of these known implants. Indeed, the folded diameter or volume is smaller than the deployed diameter by a factor of between 3 and 20, generally 3 to 8, preferably 4 to 7. This ratio naturally depends on the amount of cement injected, and some designs take advantage of the fact that the implant can be designed to expand more than necessary, notably by retaining folds in the deployed configuration. Thus, the implant volume will be determined based on the reduced size required for insertion into the bone tissue and therefore with reference to the folded volume. However, different volumes are designed for the deployed configuration, since the number and length of the folds allow for an increased deployment ratio.

[0040] The term "joined" here means that two elements are joined together, either permanently (or almost permanently), but also sometimes that a connection is made to allow one element to be operated by another. Thus, a screw or a form-based locking mechanism to temporarily secure the elements together is covered by this non-exhaustive term.

[0041] The terms ring, sleeve, or tube refer to hollow structures such as rings, conduits, or pipes, but not exclusively, including various shapes (both internally and externally), although the cylindrical shape is preferred. The term channel, on the other hand, is preferably used here to designate a passage rather than the element containing it, and the term opening refers to the fact that an element is open and capable of being traversed, leading into another structure or element. Generally, the terms sleeve and tubes or conduits refer to elements longer than rings or rings, but their use here is also not restrictive. Furthermore, the terms socket or base also refer to hollow structures that are open at one end but closed at the other, such as plugs, closures, constrictions, or constrictions, and these terms are used interchangeably without any limitation.

[0042] The term "hinge" is used here in its functional sense, without implying any structural limitation, and can in fact refer to mechanical hinges, even if they are preferably formed (as illustrated in the non-limiting examples in the figures) by thinning (or narrowing, material removal) of elements such as support arms or other components. Thus, a hinge is in fact a point or zone of articulation, since it is known in the field that it is generally safe to incorporate such pivoting mechanisms for implants because the materials used in their construction are suitable for this type of articulation.

[0043] The terms antiform fold, also called convex, and synform fold, also called concave, are used by analogy with the definitions of folds in many technical fields, including geology, but it should be understood that convexity here is defined in relation to the exterior of the implant. An antiform or convex fold is therefore a fold that folds the material inwards, while an antiform fold folds the material outwards. The succession of these two types of folds allows for minimizing the folded volume. Furthermore, some designs incorporate long and short folds in succession to facilitate rolling and / or the compaction is achieved by limiting the layering of material in the folded configuration. It should also be noted that the number of folds is not limited and, on the contrary, allows for the preservation of the implant's irregular or actual shape during deployment, which also offers advantages, particularly in terms of stabilization. Furthermore, it remains preferable to ensure an equal distribution of surface area between the folds for uniform deployment. However, the invention also envisions other applications, including folds of different sizes depending on the implant region, in order to achieve asymmetrical deployment and improved therapeutic results. Moreover, the present invention allows for control of the implant's shape once deployed by also specifying the distance between the folds.Indeed, the distance between the synform / antiform folds, and therefore the distance between long and short folds, determines how the sheet unfolds. Advantageously, if the density is higher at a certain point on the periphery, the unfolding will be greater, and if it is lower, the sheet will unfold less. It is understandable that this results in asymmetry and curvature through a more extensive unfolding in the areas with the most folds. Similarly, it is possible to use more material (a large surface area of ​​the sheet on one side, for example) so that the lateral expansion is greater on that side than the other. Furthermore, in some embodiments, the sheet is welded to the platens and therefore cannot unfold beyond the distance between the platens, which is set by the lifting mechanism.This results in an implant whose expansion is limited in one dimension (generally the essential dimension, where a precise height or width is desired), but not in another dimension. Therefore, the cement injection will expand the shell into any low-density bone volumes that may be present around the implant. It should also be noted that the fluid injection instrument can be equipped with means to control the injected pressure (a manometer, for example) and to determine the resulting volume, in order to effectively control expansion within the bone tissue.Finally, it is understood that the instrumentation proposed in this application, in certain embodiments, using a relatively conventional implant holder (or ancillary device) to hold the implant and insert it into the bone tissue, but also a less conventional one for expanding it within the bone tissue, also offers the advantage of being able to perform all the implantation and stabilization steps with a single instrument in a continuous operation. Indeed, the ancillary device, with a hollow tube for delivering the cement through the tube that retains the cement, provides an instrument that allows the surgical operation to be performed quickly and efficiently. After drilling, the implant is inserted, and without removing the instrument, the shell can be expanded with cement and then the tool removed before, during, or even after the cement has polymerized (for example, using a mechanism that cuts the hardened cement during a rotation of the instrument).The time of the surgical operation is of course significantly reduced, but also the stability of the implant, which is not released at any point until it is stabilized by the injection of cement filling all the free volumes around it, unlike some solutions of the previous art.

[0044] The terms "cylinder", "cylindrical" or "generalized cylinder" are used interchangeably in this application for the sake of clarity in describing the invention and in fact refer to All implants are "generalized cylinders," meaning three-dimensional shapes defined by a height (parallel to the longitudinal axis) and two bases (transverse to the longitudinal axis). These bases can have any shape, although a circular shape is preferred to simplify manufacturing and minimize the risk of damaging the tissues into which they are inserted. Ideally, this "cylinder" is straight, meaning its bases are aligned along the generatrix (or height) of the cylinder. Furthermore, because the implant can expand within the tissue, conforming to the shape of the space into which it is inserted (by modifying it through the pressure it exerts on these spaces), the shape may not be constant, and the two bases of the cylinder may have different shapes (surfaces).

[0045] Therefore, the term "diameter" is used in this application to designate the largest dimension of the generalized cylinder transverse to its height (or longitudinal axis), that is, in a plane (called a "transverse" plane) parallel to that of the bases of such a generalized cylinder. Thus, the term "diameter" can also refer to the length of the diagonal of a square or rectangle, or (for any shape) the greatest distance between two points contained in such a transverse plane and located on the circumference of such a cylinder. Similarly, the terms "circumference," "periphery," or "perimeter" are used here to designate the boundary of these bases of any shape.

[0046] Similarly, the terms "conical" or "truncated conical" are used here to refer to shapes that flare out from a minimum "diameter" (or area / surface) to a maximum "diameter", but they do not imply any limitation on the shape of the periphery, which may be circular or not.

[0047] In general, this application relates to an expandable bone implant (1) for veterinary orthopedic surgery, intended for restoring the volume and / or geometry of a bone by expansion between a folded and an extended configuration. The implant comprises a hollow body extending along a longitudinal axis (L) between a proximal end (11) connectable to an implantation instrument (A) for holding the implant and a distal end (12) intended to be inserted first into the bone. This proximal end is connectable to a grasping instrument (referred to as an implant holder) and thus capable of cooperating with it by means of attachment or physical connection, for example, known to those skilled in the art. However, some embodiments provide specific and advantageous attachment means to facilitate grasping the implant by an implant holder and, in particular, the release of the implant by an L-shaped movement of the implant holder.On the other hand, by being connectable to the instrument, the implant is generally actuated for expansion (here by injecting a fluid inside), as is widely known in the prior art. Indeed, many systems include expandable implants that can be actuated when mounted on an implant holder that incorporates an actuation means for implant expansion (generally a conduit and / or a rod passing through the implant holder to open into a cavity of the implant and / or cooperate with an implant component that allows its expansion; the actuation generally involves a pushing and / or pulling force). A person skilled in the art will therefore understand from reading this application that the implant can be de-. The application concludes without further detail on the instrument and its actuation, as these are standard mechanisms in the field. The system comprising the implant and the instrument is, of course, fully defined, but the implant alone is also clearly defined in its ability to be acted upon independently of the instrument, without unnecessary specification of the actuation mechanism (e.g., a sliding rod), since these mechanisms are perfectly standard or conventional in the field. It is understood within the scope of this application that the term "actable" implies a push or pull, and this application thus provides sufficient explanation for the implant to be considered clearly defined without further reference to the instrument enabling its actuation.On the other hand, some embodiments may concern the instrument itself, through an originality of its elements allowing the grasping of the implant and / or the actuation for the expansion of the implant and these characteristics then define the instrument independently of the implant since they do not particularly require details on the implant apart from those relating to the function performed by the instrument.

[0048] Such an implant (1) is preferably characterized in that: - the wall of said hollow body is formed by a sheet (10) of biocompatible metal alloy, closed on itself in a sealed manner, between said proximal (11) and distal (12) ends; - said sheet (10) has, at least in the folded configuration, a plurality of pairs of folds, each pair comprising an antiform fold (101), said convex, and a synform fold (102), said concave, said folds being laid one on top of the other in the folded configuration so that the surfaces present between each of said convex and concave folds are rolled around the longitudinal axis (L), - said proximal end (11) comprises a sleeve or ring securely attached to the flattened and rolled folds of said sheet (10) over the entire periphery of the proximal end (11), the opening through said sleeve providing an entry into the hollow body of the implant (1), - said distal end (12) comprises a sleeve closing the distal end (12) and secured, in a watertight manner, to the horizontal and rolled folds of said sheet (10) over the entire periphery of the distal end of said hollow body - said sheet (10) being plastically deformable to allow expansion of the implant from the folded configuration to the deployed configuration, when injecting a fluid into the implant (1) through said sleeve.

[0049] In some embodiments, the distance between a synform fold and the following antiform fold is longer than the distance between an antiform fold and the synform fold, to facilitate the rolling of the folds around the longitudinal axis (L). To facilitate rolling the sheet (10) onto itself and obtain a smaller folded volume, it is preferable to alternate long and short folds. For this purpose, pre-folding cams (CP) can be used, having two edges with different angles, with a star-shaped stem (TE) also having an asymmetrical shape complementary to the first angle (CPI) of the pre-folding cam and the second angle (CP2) of the pre-folding cam. as for example shown in figures 6, 7A, 7B and 7C but it is also possible to have a symmetrical pre-folding shape, as for example shown in figures 7D, 8A and 8B, even if these embodiments allow a less advantageous folding than an asymmetrical folding with an alternation of long and short folds.

[0050] In general, it is understood that the implant will retain, even in deployed configuration, at least some of the folds lying down and rolled up near the proximal and distal ends, but the dimensions and resistance properties of the sheet (10) used allow the implant to be obtained and that these persistent folds do not interfere with the function and do not cause mechanical or physiological problems in the bone tissues.In certain embodiments, the implant comprises, in deployed position, a median portion between its two ends which has a generalized cylindrical shape, with a possible and at least partial persistence of said folds, said median portion extending, on the side of the proximal end (11), by a frustoconical portion connecting the median portion to said sleeve and, on the side of the proximal end (12), by a frustoconical portion connecting the median portion to said socket, the frustoconical portions having a permanent persistence of at least a part of the folds lying down and rolled up near the proximal (11) and distal (12) ends.

[0051] In some embodiments, said sheet is plastically deformable also from the folded configuration to the deployed configuration, in particular thanks to the persistence of the horizontal and rolled folds at the proximal and distal ends, to allow reversibility of the expansion.

[0052] In certain embodiments, said sleeve is able to cooperate with the distal end of an implantation instrument (A) passing through said implant via the opening of the proximal end (11), for example by means of at least one housing and / or protrusion complementary to at least one protrusion and / or housing of said instrument (A) which includes a hollow tube (A1) able to pass through said sleeve and whose inner conduit opens into said hollow body of the implant (1) through at least one opening (A2) allowing the injection of said fluid into the implant (1).

[0053] In certain embodiments, said sheet is secured to said sleeve at the proximal end (11) by a weld (110) fixing the proximal end of the folds lying and rolled against the outer wall of said sleeve and / or secured to the base of the distal end (12) by a weld (120) fixing the distal end of the folds lying and rolled against the outer wall of said sleeve.

[0054] In some embodiments, said sheet is compressed around the ring at the proximal end (11) and / or around the base at the distal end (12) by a second ring, called a compression ring, keeping the folds lying flat and rolled against the outer wall of said sleeve and / or said socket.

[0055] In some embodiments, the folds are, at least in the folded configuration, parallel to the longitudinal axis (L). In some embodiments, the outside diameter of said sleeve (10) and / or said ring is less than or equal to the maximum folded diameter of the implant. In some embodiments, the number of fold pairs is between 3 and 16, generally 4 to 12, preferably around 8. However, 3 folds Sometimes, a few folds are sufficient, particularly for small implants in small animals or small bones. However, the greater the number of folds, the less material will deform, the lower the risk of tearing, and the easier the deployment. Therefore, up to 20 folds are possible even for medium-sized animals, and for large animals such as horses, 25 to 30 folds, or even more, are possible.

[0056] In some embodiments, the sheet (10) is closed on itself by means of two folds in opposite directions (synform and antiform), made on the two opposite edges of the sheet, so as to fit together and form a longitudinal closure and give the sheet (10) a generalized cylindrical shape, at least before the making of folds and their rolling.

[0057] In some embodiments, the sheet (10) has a thickness of between 3 and 100 microns, generally between 6 and 50 and preferably between 15 and 30 microns. In some embodiments, the sheet (10) is made of titanium alloy.

[0058] In some embodiments, the sheet also includes at least one pair of folds (a synform fold and an antiform fold) with an axis not parallel to the longitudinal axis (L), preferably perpendicular for an expansion of the implant also in length or oblique for a curved expansion of the implant.

[0059] In some embodiments, the distance between the folds is variable along the circumference of the implant, so that the shape of the implant in deployed configuration is curved or asymmetrical.

[0060] In some embodiments, said folded diameter is less than the unfolded diameter by a factor of between 3 and 20, generally 3 to 8, preferably 4 to 7.

[0061] The present application also relates to an orthopedic treatment system for damaged bone tissue comprising a bone replacement cement and at least one instrument (A) for implanting and injecting cement into the implant, characterized in that it comprises an implant according to one of the preceding claims.

[0062] In some embodiments, the implantation and cement injection instrument includes means for controlling the pressure and / or suction of the cement to fold the implant into a folded configuration if necessary.

[0063] In some embodiments, the implantation instrument is separate but complementary to the injection instrument, the cement injection channel of which passes through a channel inside the stem of the implant instrument, holding the proximal end of the implant by means of its distal end.

[0064] This application also relates to a method for manufacturing an implant according to one of the preceding claims, characterized in that it comprises: The sheet is closed upon itself and welded to form a generalized cylinder. Insertion of the closed sheet onto a generalized cylindrical matrix having a star-shaped base, the number of points of the star defining the number of fold pairs of said sheet of said implant Compression of the closed sheet between said matrix and a plurality of salient elements of complementary shape to the hollows between the branches of the star. Rolling the folds of said sheet around the longitudinal axis. Securing said sheet to said socket and ring.

[0065] For example, the rolling can be done by introducing the closed and pre-folded sheet into a conduit whose diameter gradually narrows to the desired diameter for the implant, by sliding and rotating the implant in this conduit (for example with a guide inside the sheet to prevent it from being crushed).

[0066] The sheet is generally joined to the sleeve and bushing by welding (120), preferably after first flattening the sheet around the circumference of the bushing or sleeve, for example with a compression ring (121), examples of which are shown in some figures. While direct welding is possible, flattening the folds in the correct position is preferable.

[0067] The illustrative and non-limiting figures in this application will now be described in detail to better explain the various embodiments and provide examples of structural elements usable in the context of the foregoing. The following should therefore not be considered exhaustive, as the various elements or components illustrated are only examples, and the figures may combine elements or components that are not necessarily dependent on one another.

[0068] Figure 1A represents a perspective view of an expandable implant in its folded configuration, according to certain embodiments, with a proximal seal (110) of the sheet (10) on the proximal end (11) of the implant (1) and with a distal seal (120) of the sheet (10) on the distal end (12) of the implant (1) and Figure IB represents a perspective view of the same implant in its deployed configuration, but with the proximal seal formed by a split ring, as described later in this application.

[0069] Figure 2A shows a perspective view of an expandable implant in its deployed configuration, held by an implantation instrument, according to certain embodiments. Figure 2B shows a perspective view of the same implant with a cross-section showing the implantation instrument inside the implant. Figure 2B is a perspective view with a partial cross-section of the implant shell after it has been deployed by cement injection. This occurs during the withdrawal of the injection instrument by sliding its cannula (A1) within the cannula (A) of the insertion instrument (implant holder), which holds the proximal end of the implant (1). The distal end of the cannula (A1) cooperates with a distal end of the implant (1) during implantation to retain the distal end (12) and inject the cement through holes (A2) opening from the inside of the cannula (A1) into the inside of the shell.During the withdrawal of the injection cannula (Al), at the end of deployment, the holes (A2) are closed by the inside of the cannula (A) of the implant holder (A) and the distal end of the injection cannula (Al) preferably has a plug (A12) which then ensures at this time a discontinuity between the inside of the injection cannula (Al) and the inside of the implant, facilitating the polymerization of the cement without it. propagates within the instrumentation, facilitating implant release, preferably once the cement has polymerized. If the tip is open without such a cap (A12), then the cannula must be breakable and possibly equipped with a means of cutting or breaking the polymerized cement it contains when releasing the implant into the implantation site. Indeed, in some embodiments, the distal end of the cannula (A1) is open to allow cement injection through this end, and the holes (A2) can then be omitted. However, it is still preferable to use such holes (A2) allowing cement to exit laterally inside the implant, around the circumference of the cannula (A1) and over a portion of significant size relative to the size of the implant.

[0070] In some embodiments, the implant may include a second sheet (10b) surrounding the first sheet, made of the same or a different material, to form a double envelope, for example as shown in Figure 2C. Such a double envelope can offer many different advantages, including thermal insulation protecting the tissues from the heat of polymerization (for example, through a heat-limiting fluid) or simply to ensure additional security by preventing cement leakage in the event of a tear in one of the sheets.In this case, at least one end of the implant, particularly the proximal end (11), may have an additional concentric ring or base around the first ring or base, or, for example as shown in Figure 2C, a two-channel ring or a double ring, to secure this second leaf (10b) while maintaining a space between it and the first leaf (10). However, it is also possible to join these two leaves (10, 10b) together at their ends. In the case of two leaves spaced further apart, an injection port can be provided between the two leaves (10, 10b) for a fluid different from or the same as the first, for example, via a double ring or a single two-channel ring.Such a double ring can, for example, include spacers between a first ring and a second ring (11b) concentric with the first, forming an annular conduit between them for injecting this second fluid (such as a lubricant that improves the sliding of one sheet relative to the other, thus facilitating deployment). Of course, other arrangements are possible, provided they include a conduit opening into the envelope formed by the first sheet and another opening into the space between the two sheets. These two sheets can then be folded and rolled simultaneously or successively during manufacturing, but their welds (or compression bonds), to each other and / or to the ring and / or the base, will be made sequentially to maintain the space between them.These double-sheet embodiments allow for preforming the injection site (by compressing the cancellous bone tissue) but can also, for example, allow for two-stage injection of the fluid for better adjustment of the shape, the resulting temperature in the tissues, and / or the polymerization rate of the fluid (for example, by adjusting the cement compound mixture). Furthermore, since it is possible to use a second fluid other than cement inside, the compartment between the two sheets can be used as a cooling circuit by circulating a fluid. the polymerization of the cement, in order to protect the tissues from the heat produced during said polymerization. Such a double-leaf implant (1) therefore requires a double cannula comprising two concentric or parallel channels, each opening into one of the spaces provided, as a person skilled in the art will understand from Figure 2C without further explanation being necessary.

[0071] Figure 3A represents a perspective view of an expandable implant in a semi-deployed configuration, according to certain embodiments; Figure 3B represents a perspective view of a sheet used for the manufacture of an expandable implant according to certain embodiments in a semi-folded configuration; and Figure 3C represents a perspective view of this same sheet in a folded configuration.

[0072] Figure 4A represents a perspective view of an expandable implant in folded configuration with a weld line (110) at the proximal end (11) and a weld line (120) at the distal end (12) and Figure 4B represents an enlargement of Figure 4A at the distal end showing the distal butt plugging the distal end of the implant.

[0073] Figure 5A shows a perspective view of a folding guide tool for a sheet of an expandable implant, according to certain embodiments guided by a guide tube. Figure 5B shows a side view of this same tool with the folded sheet. Enlargements 5C and 5D show side views of the sheet's overlap at the point of closure, according to two different embodiments. To obtain a sheet (10) folded into a cylinder, an internal guide (TG) is preferably used, such as a guide tube (but potentially a roller whose relative position with the sheet is preferably movable parallel to the longitudinal axis).This guide allows the sheet (10) to be rolled up and inserted into an external guide (GR), such as a folding guide with a channel to receive the folded sheet, as illustrated, for example, in Figure 5A, or an external roller, preferably movable in conjunction with the internal guide, so as to allow welding as the rollers move along the longitudinal axis corresponding to the height of the cylinder. Guiding the sheet with at least one of the internal and external guides allows the two edges (or ends) of the sheet (10), initially rectangular and folded over itself, to be positioned so that two of its edges partially overlap.These edges placed one above the other can then be welded together, for example as shown in Figure 5C, but it is possible to make 2 folds in opposite directions on each of these two edges of the sheet to obtain interlocking folds, for example as shown in Figure 5D, which makes it easier to weld, in particular by limiting the risks of puncturing the sheet and / or improving the reliability and stability of the implant, especially during its subsequent deployment.

[0074] Figure 6 shows a perspective view of a pre-folding tool for expandable implant sheets according to certain embodiments, using a pre-folding plate. Such a pre-folding plate has a rod with a star-shaped cross-section, called a star rod (ST), onto which the sheet, folded back on itself into a cylinder shape, can be threaded to partially flatten (deform, pre-fold) it. The sheet is pressed against the star-shaped rod using cams having one or more edges that conform to the outer shape of the star-shaped rod. Figure 6 illustrates a preferred embodiment of a tool for creating alternating long and short folds or alternating symmetrical folds, depending on the shape of the ends of the pre-folding cams (PFs) cooperating with a star-shaped rod (ST) of complementary shape to pre-fold the sheet between the rod and the cams. Indeed, some embodiments of such a tool include ramps (RCs) carrying pre-folding cams (PFs) that may have two edges (with two ridges) having different angles (relative to the cam sliding axis).Thus, a first cam angle (CPI) and a second cam angle (CP2) are used, differing to obtain long and short folds, while cams (CP) with a single edge and identical cam angles from one cam to the other produce symmetrical folds. The folding cams, by sliding on their respective cam ramps, deform (e.g., flatten) and pre-fold the sheet (10), which has been previously folded into a cylindrical shape. For this purpose, the sheet (10) is inserted onto a star-shaped rod (TE) whose cross-section has a star shape with asymmetrical points for long and short folds, or with symmetrical points for symmetrical cams and folds, as illustrated in Figures 7B and 7D, respectively.

[0075] Figure 7A shows an enlargement of Figure 6, while Figures 7B, 7C, and 7D show top views of different embodiments of the pre-bending tool with a sheet of the implant slid around a star-shaped rod of the pre-bending tool. In the enlargement of part of Figure 6 onto Figure 7A, the interaction between the pre-bending cams and the star-shaped rod is more easily observed.Figure 7C represents a variant embodiment in which the star-shaped stem has branches whose dimensions vary around the circumference of the star-shaped stem, which implies that the corresponding cams will have different shapes from one cam to another, whether it is to obtain long folds and short folds as in the example shown or symmetrical folds, so that the sheet folded into the shape of an asymmetric flattened cylinder has, once pre-folded by this tool, an asymmetric shape which it will also retain once unfolded.

[0076] Figure 8A shows an example of a sheet folded into a cylinder that has been pre-bonded with symmetrical folds, and Figure 8B shows this same sheet compressed upon itself to reduce its diameter, for example, to the maximum extent until its internal folds (102) are adjacent to each other. It should be noted that in such an embodiment, it is still possible to reduce the diameter of the envelope formed by the sheet, for example, by inserting the sheet into a conical tube or by other means to flatten the periphery of the sheet, and in particular the external folds (101).

[0077] Figure 9A represents a top view of an instrument for inserting an implant into a vertebral body according to the prior art and / or the present invention and Figure 9B represents a perspective view of such an insertion of an implant of the prior art, while Figure 9C represents a perspective view of the implantation of an implant according to the present invention, once deployed inside the vertebral body.

[0078] It should be noted that the tool shown in Figure 6 is not strictly necessary and that other folding methods can be considered, although this tool is particularly effective and reliable in producing the results obtained. Furthermore, synchronous sliding between the different folding cams on their respective ramps is preferable, and such synchronous sliding can be achieved, for example, by electronically controlling the cams' movement on their ramps. It is also possible to perform this folding without synchronization between the cams, but in this case, it is preferable that the folds be made successively in the same direction, tangentially to the sheet's circumference, and in a regular manner to avoid folding defects and sheet deformation. The sheet, while relatively flexible, can be fragile if deformed too tightly.It should also be noted that in the case of symmetrical folds, such as those shown in Figures 8A and 8B, the limited deployment range, as illustrated in Figure 8B, can sometimes be advantageous because it helps to minimize the risk of unwanted bone tissue deformation during implant deployment. Indeed, the flexibility of the sheet allows it to adapt to the anatomical shape to restore the physiological geometry of the bone tissue (whether vertebral or not). However, the cement injection pressure is generally high enough to potentially cause excessive tissue deformation, and therefore, controlling the final implant volume, as well as the deployment range, is preferable.Thus, the ratio between the folded volume and the unfolded volume is a significant advantage achieved through the (origami-like) folding technique in the present invention. This technique ensures not only the final volume but also the shape of the implant once unfolded. The use of symmetrical or asymmetrical folds, or combinations thereof, around the circumference of the implant allows for an optimized (or even custom) final shape to fill the space required for the geometric restoration of the structure.

[0079] Figures 10A, 10B, and 10C show profile views of a fractured vertebra, respectively in its anterior, mid, and posterior portions. The invention allows for the treatment of this type of vertebral fracture by positioning the deployable implant correctly in the plane of the implantation site, with an anteroposterior and / or mediolateral positioning, and by adjusting the insertion depth and / or insertion angle of the implant, according to the type of surgical approach used (e.g., lateral, anterior, dorsal, transforaminal, transpedicular, etc.).

[0080] This application describes various technical features and advantages with reference to the figures and / or various embodiments. Those skilled in the art will understand that the technical features of a given embodiment can in fact be combined with features of another embodiment unless the contrary is explicitly stated, or it is obvious that such features are incompatible, or that the combination does not provide a solution to at least one of the technical problems mentioned in this application. Furthermore, the technical features described in a given embodiment can be isolated from the other features of that embodiment unless the contrary is explicitly stated.

[0081] Detailed list of references in the figures: I implant 10 sheets 10b second sheet 101 anti-forming fold 102 synformal fold II proximal end 11b second ring 110 proximal weld 12 distal end 120 distal weld (watertight connection) 121 Compression fastening (e.g., split ring) An implantation instrument The hollow tube A2 opening of the hollow tube Al 2 distal plug TG internal guide GR external guide PP Pre-folding plate TE star-shaped stem PP pre-folding plate CP pre-folding cam CPI first pre-bending cam angle CP2 second pre-bending cam angle RC cam ramp V vertebra VCF vertebral compression fracture

Claims

Demands

1. Veterinary orthopedic surgery expandable bone implant (1) for restoring the volume and / or geometry of a bone, by expansion between a folded and an deployed configuration, said implant comprising a hollow body extending along a longitudinal axis (L) between a proximal end (11) connectable to an implantation instrument (A) for holding the implant (1) and a distal end (12) intended to be inserted first into the bone, said implant (1) being characterized in that: - the wall of said hollow body is formed by a sheet (10) of biocompatible metal alloy, closed on itself in a sealed manner, between said proximal (11) and distal (12) ends; - said sheet (10) has, at least in the folded configuration, a plurality of pairs of folds, each pair comprising an antiform fold (101), said convex, and a synform fold (102), said concave, said folds being laid one on top of the other in the folded configuration so that the surfaces present between each of said convex and concave folds are rolled around the longitudinal axis (L), - said proximal end (11) has a ring securely attached to the flattened and rolled folds of said sheet (10) over the entire periphery of the proximal end (11), the opening through the ring providing an entry into the hollow body of the implant (1), - said distal end (12) comprises a base closing the distal end (12) and securely attached to the flattened and rolled folds of said sheet (10) over the entire periphery of the distal end (12) of said hollow body - said sheet (10) being plastically deformable to allow the expansion of the implant from the folded configuration to the deployed configuration, when a fluid is injected inside the implant (1).

2. Implant according to claim 1, characterized in that the distance between a synform fold and the next antiform fold is longer than the distance between an antiform fold and the synform fold, to facilitate the rolling of the folds around the longitudinal axis (L).

3. Implant according to any one of the preceding claims, characterized in that the implant (1) comprises, in deployed position, a median portion between its two ends which has a generalized cylindrical shape, with a possible and at least partial persistence of said folds, and at each of its two ends, a frustoconical portion connecting the median portion to the base and the ring, with a permanent persistence of at least a part of the folds lying down and rolled up near the ends.

4. Implant according to any one of the preceding claims, characterized in that said sheet is plastically deformable also from the folded configuration to the deployed configuration, in particular due to the persistence of the horizontal folds and wrapped at the proximal and distal ends, to allow reversibility of the expansion.

5. Implant according to any one of the preceding claims, characterized in that said butt is able to cooperate with the distal end of an implantation instrument (A) passing through said implant via the opening of the proximal end (11), for example by means of at least one housing and / or protrusion complementary to at least one protrusion and / or housing of said instrument (A) which comprises a hollow tube (A1) whose inner channel opens into said hollow body of the implant (1) by at least one opening (A2) allowing the injection of said fluid into the implant (1).

6. Implant according to any one of the preceding claims, characterized in that said sheet is secured to the ring at the proximal end (11) by a weld (110) fixing the folds lying flat and rolled against the outer wall of said ring.

7. Implant according to any one of the preceding claims, characterized in that said sheet is secured to the base of the distal end (12) by a weld (120) fixing the folds lying flat and rolled against the outer wall of said ring.

8. Implant according to any one of the preceding claims, characterized in that said sheet is compressed around the ring at the proximal end (11) and / or around the base at the distal end (12) by a second ring, called compression ring, keeping the folds lying flat and rolled against the outer wall of said ring and / or said base.

9. Implant according to any one of the preceding claims, characterized in that the folds are, at least in the folded configuration, parallel to the longitudinal axis (L).

10. Implant according to any one of the preceding claims, characterized in that the outside diameter of said base and / or of said ring is less than or equal to the maximum folded diameter of the implant.

11. Implant according to any one of the preceding claims, characterized in that the number of pairs of folds is between 3 and 16, generally 4 to 12, preferably in the order of 8.

12. Implant according to any one of the preceding claims, characterized in that the sheet (10) is closed upon itself by means of two folds in opposite directions (synform and antiform), provided on the two opposite edges of the sheet, so as to fit together and form a longitudinal closure and give the sheet (10) a generalized cylindrical shape, at least before the making of folds and their rolling.

13. Implant according to any one of the preceding claims, characterized in that the sheet (10) has a thickness between 3 and 100 microns, generally between 6 and 50 and preferably 10 and 30 microns.

14. Implant according to any one of the preceding claims, characterized in that the sheet (10) is made of titanium alloy.

15. Implant according to any one of the preceding claims, characterized in that the sheet also comprises at least one pair of folds (a synform fold and an antiform fold) with an axis not parallel to the longitudinal axis (L), preferably perpendicular for an expansion of the implant also in length or oblique for a curved expansion of the implant.

16. Implant according to any one of the preceding claims, characterized in that the distance between the folds is variable along the circumference of the implant, so that the shape of the implant in deployed configuration is curved or asymmetrical.

17. Implant according to any one of the preceding claims, characterized in that said folded diameter is less than the deployed diameter by a factor of between 3 and 20, generally 3 to 8, preferably 4 to 7.

18. An orthopedic treatment system for damaged bone tissue comprising a bone replacement cement and at least one instrument (A) for implanting and injecting cement into the implant, characterized in that it comprises an implant according to one of the preceding claims.

19. System according to claim 18, characterized in that the implantation and cement injection instrument includes means for controlling the pressure and / or suction of the cement to fold the implant into a folded configuration if necessary.

20. System according to any one of claims 18 and 19, characterized in that the implantation instrument is different from but complementary to the injection instrument, the cement injection channel of which passes through a channel inside the stem of the implant instrument holding the proximal end of the implant by means of its distal end.

21. A method for manufacturing an implant according to any one of the preceding claims, characterized in that it comprises: - The sheet is closed upon itself and welded to form a generalized cylinder - Insertion of the closed sheet onto a generalized cylindrical matrix having a star-shaped base, the number of points of the star defining the number of pairs of folds of said sheet of said implant. Compression of the closed sheet between said matrix and a plurality of salient elements of complementary shape to the hollows between the points of the star. - Rolling the folds of said sheet around the longitudinal axis. Securing said sheet to the base and the ring.

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