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

Abstract

The present invention relates to an implant, to a system and to a manufacturing method for human orthopedic surgery for restoring the volume and / or geometry of a bone by expansion, at least two faces of the implant each comprising a plateau, wherein bringing the distal (12) and proximal (11) ends closer together causes the support arms to pivot, thereby causing the plateaus to move away from one another and, consequently, the implant to expand, characterized in that it comprises an envelope enclosing the implant and in that: - the envelope is formed by a sheet (10) made of a biocompatible metal alloy, sealingly closed upon itself with a plurality of pairs of flattened folds laid one over the other and wound around the longitudinal axis (L); - the sheet (10) is plastically deformable so as to allow the implant to expand from the folded configuration to the deployed configuration.

Description

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

[0001] This application relates to the field of surgery, in particular human orthopedic surgery, and specifically to the treatment of collapsed bone structures by restoring their volume (or straightening them). 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 prior art, notably documents EP1308134, US9510877, US8936627, and EP2467099, that devices for realignment and stabilization (or reduction of bone fractures), particularly of the spine, are available in the form of stents, or in the form of porous balloons or inflatable bags as described in documents EP1408888 and EP1379185, possibly equipped with support plates as described in document US20060100706. Numerous 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 meshed tubular 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: balloon inflation 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. Furthermore, these solutions have the drawback of not addressing the major problem of cement leakage.

[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 fabric, or even elastic, or semi-rigid ("conformable") or rigid, or made of shape-memory material, with a continuous or fenestrated (i.e., meshed) wall, and which could be porous or non-porous. However, all the hypotheses described in these documents primarily define possible treatment methods and objectives to be achieved, without These proposals fail to provide any real instruction regarding the technical characteristics or structural arrangement of implants, nor on how to obtain such implants and thus implement these methods. Therefore, these proposals 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), which directly impacts the success of the operation. Therefore, it is clear 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 understood that there persists in the field a technical problem concerning the restoration of bone structure (straightening or reduction of fracture or increase in volume after collapse) using an expandable (deployable) implant that is capable of expanding collapsed bone tissues and sufficiently impermeable to avoid or limit the leakage of cement outside the implant with control of the injection site.

[0012] Finally, a major problem that persists in the field concerns technical feasibility. of the fabrication of 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, which could be either soft and flexible like a membrane or tissue, or semi-conformable or rigid, or made of shape-memory material, with a continuous or fenestrated (i.e., meshed) wall, and which could be porous or non-porous. However, this document only describes possible treatment methods but provides no guidance regarding the technical characteristics or structural arrangement of these numerous hypothetical implants used for 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 enable expansion without rupture of the pocket, 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 human orthopedic surgery, used to restore the volume and / or geometry of a bone. This is achieved through expansion between a folded and an unfolded configuration. The implant extends along a longitudinal axis from a proximal end, which can be connected to an implantation instrument to hold the implant, to a distal end intended for initial insertion into the bone. This proximal end can be connected to a grasping instrument (called an implant holder) and is thus capable of cooperating with it, using means of attachment or physical connection, such as those known to those skilled in the art. However, some embodiments incorporate specific and advantageous attachment methods to facilitate grasping the implant by an implant holder and, more importantly, to release the implant through an L-shaped movement of the implant holder.On the other hand, by being connectable to the instrument, the implant is generally actuated for its expansion (notably by injecting a fluid inside and / or by pushing or pulling on an element of the implant), as was 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 involving a pushing and / or pulling force). The person skilled in the art will therefore understand from reading this application that the implant can be defined without further detail on the instrument and on the actuation since these are classic mechanisms in the field and that the system including the implant and the instrument is of course totally defined but that the implant alone is in fact also well defined in its character to be acted independently of the instrument and without unnecessary detail on the actuation mechanism (sliding rod for example) insofar as these are perfectly standard or conventional mechanisms in the field.It is understood within the scope of this application that the term "actuable" implies a push or pull (with or without rotation), and this application thus provides sufficient explanation for the implant to be considered clearly defined without further reference to the instrument enabling its actuation. Conversely, some embodiments may relate to the instrument itself, through the originality of its elements enabling the grasping of the implant and / or actuating it for expansion. These characteristics then define the instrument independently of the implant, since they do not particularly require details about the implant other than those relating to the function performed by the instrument.

[0015] Furthermore, at least two faces of the implant, for example upper and lower, each comprising a tray for contact with bone tissue, each of the trays comprising a central portion connected, via at least one hinge, to at least one pair of support arms, each oriented in opposite directions within each pair, one arm of each pair being connected by a hinge to the distal end while the other arm is connected by a hinge to the proximal end, the implant comprising a central axis or a housing suitable for receiving such an axis extending through a sliding sleeve at the proximal end to a traction ring or sleeve at the distal end where said axis is configured to transmit traction, when actuation by said instrument, to the distal end to enable it to be brought closer to the proximal end,by causing the pivoting of the support arms, resulting in the separation of the platforms from each other and, consequently, the expansion of the implant between the folded and deployed configurations, such an implant (1) is preferably characterized in that it comprises a casing enclosing said implant from the proximal end to the distal end and in that: - said envelope is formed by a sheet of biocompatible metal alloy, sealed tightly upon itself; - said sheet presents, at least in the folded configuration, a plurality of pairs of folds, each of the pairs comprising an antiform fold, called convex, and a synform fold, called concave, said folds being laid one on top of the other in folded configuration so that the surfaces present between each of said convex and concave folds are rolled around the longitudinal axis; - said proximal end extends into a sealing sleeve securely attached to the flattened and rolled folds of said sheet over the entire periphery of the proximal end; - said distal end extends into a socket securely attached, in a watertight manner, to the flattened and rolled folds of said sheet over the entire periphery of the distal end of said implant; - said sheet is plastically deformable to allow the expansion of the implant from the folded configuration to the deployed configuration by forming a sealed envelope enclosing the implant and preventing leaks when injecting a fluid into the implant and the envelope.

[0016] 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 next synform fold, to facilitate the rolling of the folds around the longitudinal axis of the implant in the folded configuration.

[0017] According to another feature, said sealing sleeve extends said proximal end, parallel to the longitudinal axis, to a distance which is greater than or equal to that to which the trays extend from the center of the implant

[0018] According to another feature, said sealing sleeve has a through opening whose diameter is greater than or equal to that of the opening of the sliding sleeve, so that these two sealing and sliding sleeves provide an entry into the hollow body of the implant from a conduit of an implantation instrument holding the implant at the proximal end, capable of conveying a fluid to be injected into said implant.

[0019] According to another feature, the implant has, in the deployed position, a middle portion between its two ends which has a generalized cylindrical shape of length greater than or equal to that of the plates, with a possible and partial persistence of said folds, said middle portion extending, on the side of the proximal end, by a truncated conical portion connecting the middle portion to the sleeve and, on the side of the distal end, by a truncated conical portion connecting the middle portion to the 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.

[0020] According to another characteristic, the said sheet is also plastically deformable from the deployed configuration to the folded configuration, without tearing of the sheet thanks to the thinness of the sheet and in particular thanks to the persistence of the horizontal and rolled folds at the proximal and distal ends, facilitating the reversibility of the expansion.

[0021] According to another feature, said central axis is able to cooperate with and / or extends beyond the distal end of an implantation instrument at the level of the proximal end of the implant and having an internal conduit in communication with a conduit provided in said central axis opening into the space provided by the spacing of the plates, via at least one opening allowing the injection of said fluid into the implant.

[0022] According to another feature, said sheet is joined at the proximal end with the proximal end of the flat and rolled folds which is welded against the outer wall of said sliding sleeve and / or joined at the distal end with the distal end of the flat and rolled folds which is welded against the outer wall of said traction sleeve by a weld.

[0023] According to another feature, said sheet is compressed around the sleeve at the proximal end and / or around the socket at the distal end by a compression ring keeping the folds lying flat and rolled against the outer wall of said sleeve and / or socket.

[0024] According to another peculiarity, the folds are, at least in the folded configuration, parallel to the longitudinal axis.

[0025] 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.

[0026] According to another characteristic, the number of pairs of folds is between 3 and 16, generally 4 to 12, preferably around 8.

[0027] 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.

[0028] Another distinctive feature is that the sheet is made of titanium alloy.

[0029] According to another peculiarity, the distance between the folds is variable from one lateral face to the other of the implant, so that the shape of the implant in deployed configuration is curved and / or asymmetrical transversely to the longitudinal axis.

[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 at least one implant, a bone replacement cement and at least one instrument for implanting and injecting cement into the implant, said system being characterized in that said implant is an implant according to one of the embodiments described in this application.

[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 obtaining an implant according to the present invention. This objective is achieved by a method for manufacturing an implant according to one of the preceding claims, characterized in that it comprises: - Obtaining an expandable implant with two platforms that move apart under the effect of bringing the ends of the implant together thanks to support arms connecting these ends to the platforms; - Closing the sheet onto itself and welding to form a generalized cylinder; - Insertion of the closed sheet onto a generalized cylindrical matrix having a star-shaped base, called a star stem, 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 branches of the star; - Rolling the folds of said sheet around the longitudinal axis, - Insertion of said expandable implant inside said compressed sheet; - Securing the said sheet to the socket and the sleeve.

[0035] 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: Figure 1A represents a perspective view of an implant in its folded configuration, according to certain embodiments, and Figure IB represents a perspective view of the same implant in its deployed configuration; Figure 2A shows a perspective view of an implant without a shell with fewer folds than the implant in Figure 1A, and Figure 2B shows a perspective view of the same implant in Figure 2A in its deployed configuration with half of its shell removed to reveal the implant inside; Figure 3A shows a perspective view of an expandable implant without its shell in certain embodiments in its folded configuration, and Figure 3B shows a perspective view of a double-shell implant in its deployed configuration in certain embodiments; Figure 4A represents a cross-sectional view of an expandable implant carried by an implantation instrument and with an enlargement showing details of the support arms of such an implant with a self-locking mechanism; Figure 4B represents a cross-sectional view of a vertebra in which an expandable implant is implanted according to other embodiments; Figure 5A represents a top view of a vertebra in which an implant is implanted according to various embodiments, Figure 5B represents a perspective view of a vertebra in which an implant of the anterior art is implanted and Figure 5C represents a perspective view of a vertebra in which an implant is implanted according to certain embodiments; Figure 6A represents a perspective view of an implant according to certain embodiments and Figure 6B represents a perspective view of an implant according to other embodiments; Figure 7A represents a profile view of an expandable implant according to certain embodiments and Figure 7B represents a profile view of the sheet cover at the level of its closure; Figure 8A shows a perspective view of an expandable implant in a semi-deployed configuration, according to certain embodiments; Figure 8B shows a perspective view of a sheet used for manufacturing an expandable implant according to certain embodiments in a semi-folded configuration; and Figure 8C shows a view in perspective of the same sheet in folded configuration; Figure 9A represents a perspective view of an expandable implant in folded configuration with weld lines at the proximal and distal ends, and Figure 9B represents an enlargement of Figure 9A at the distal end; Figures 10: Figure 1 OA 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 10B represents a profile view of this same tool with the folded sheet, the enlargements 10C and 10D representing profile views of the cover of the sheet at the level of its closure according to two different embodiment examples; Figure 11 represents a perspective view of a sheet pre-folding tool for a plan according to the various embodiment with a pre-folding plate; Figure 12A represents an enlargement of Figure 11, Figures 12B, 12C and 12D represent top views of different embodiments of the pre-bending tool with its star-shaped stem and the implant sheet slid around it; Figure 13A represents a perspective view of a pre-folded sheet using a star-shaped rod such as that of Figure 12D and Figure 13B represents this same sheet folded on itself, according to certain embodiments Figure 13A represents a top view of a vertebra in which an implant is implanted according to various embodiments; Figures 14A, 14B and 14C represent profile views of vertebrae that have suffered vertebral compression fractures (VCF) at the anterior medial and posterior levels respectively; Figure 15A represents a perspective view of an implant without its leaf according to certain embodiments and Figure 15B represents the same implant from which the expansion rod has been removed and Figure 15C represents a cross-sectional view of Figure 15A of the implant in which the expansion rod is present.

[0036] 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 may be affected include the femur or humerus (head), for example, in cases of risk of collapse. Furthermore, the tibial plateau is frequently subjected to crushing, and the implants or systems described in this application are useful for restoring height in all types of bone crushing or collapse, for example, in the distal part of the humerus or femur. On the other hand, as per... As demonstrated in document EP2921142, expandable implants can be used as bone anchors, and such use is also possible for implants like those described in this application. In this case, the implants will be extended at their proximal end by an elongated body onto which another type of orthopedic implant or a surgical device for fixing other elements can be attached. However, when used as a bone anchor in a vascularized structure, such as a humeral or femoral head, the size of the implant relative to the bone structure should preferably be limited to preserve vascularization and promote bone healing.

[0037] Some embodiments involve the injection of 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 restrictive, 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 stainless steel or their alloys.Recent techniques are being used to produce 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 incorporating folds arranged longitudinally on the implant. In particular, it is possible to design a maximum deployed volume that exceeds the volume required for the intended 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 bonded folds, it is possible to obtain expansion ratios, between the refolded volume and the deployed volume, ranging from 2 to 20, or even 30, and it is also possible to control the shape of the implant in the deployed configuration, according to the arrangement of the folds, in the manner of an ori-. garnished. 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 useful to administer molecules through such a controlled release of this fluid. Thus, various embodiments incorporate a certain porosity of the sheets (10) at least in certain portions of the implant, for example, through microscopically sized holes of controlled number and density.In any case, this type of sheet is capable of reversible plastic deformation a sufficient number of times for the intended application, as it notably offers the possibility of retracting the sheet's outer layer in case of problems (biocompatibility and tear resistance). Indeed, generally, the cement dosage control allows monitoring of the fifteen-minute polymerization period, during which it is possible to retract the outer layer and aspirate the cement. Furthermore, through cement injection and the swelling of the outer layer, 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. From such a sheet, it is necessary to obtain a closed structure, which requires folding the sheet back on itself and locking it in position.To achieve this, a weld (or a bond or a braze, these terms are not exhaustive here) can be made between two overlapping edges or on edges with interlocking folds, to facilitate and strengthen the weld. Some designs therefore incorporate external welding, which is simplified and more robust thanks to the layering of materials at these complementary folds.

[0038] Various embodiments allow for the creation of an expandable implant with very small dimensions in its folded configuration while ensuring a satisfactory volume in its deployed configuration. Thus, the passage required for insertion of the implants described in this application 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 embodiments take advantage of the fact that the implant can be designed to expand beyond what is necessary, notably by retaining folds in the deployed configuration. Therefore, the implant volume will be determined based on the reduced size required for insertion into the bone tissue and thus with reference to the folded volume.However, different volumes are planned for the deployed configuration, since the number of folds and the length of the folds allows the deployment ratio to be increased.

[0039] 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 actuated by another. Thus, a screw or a form-based locking mechanism to temporarily secure the elements together is covered by this non-exhaustive term.

[0040] 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.

[0041] 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.

[0042] 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 is defined here in relation to the outside 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 the two types of folds allows for minimizing the folded volume. In addition, some embodiments incorporate long and short folds to facilitate rolling and / or compaction, limiting the overlap of material in the folded configuration. To facilitate rolling the sheet (10) upon itself and obtain a smaller folded volume, it is preferable to use alternating long and short folds.For this, it is possible to use pre-folding cams (CP) having two edges with different angles, with a star-shaped rod (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 shown for example in figures 11, 12 A, 12B and 12C but it is also possible to have a symmetrical pre-folding shape, as shown for example in figures 12D, 13A and 13B, even if these embodiments allow a less advantageous folding than an asymmetrical folding with an alternation of long and short folds.

[0043] Generally speaking, it is understood that the implant will retain, even in its deployed configuration, at least some of the folds of the leaf near the proximal and distal ends, but the dimensions and resistance properties of the leaf (10) used allow- proving that the implant is obtained and that these persistent folds do not interfere with function and do not cause mechanical or physiological problems in the bone tissues.

[0044] It should also be noted that the number of folds is not limited and, on the contrary, allows the irregularity or actual shape of the implant to be maintained 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, but the invention also envisions other applications, including folds of different sizes depending on the region of the implant, in order to obtain asymmetrical deployment and improved therapeutic results. Moreover, the present invention makes it possible to control the shape of the implant once deployed by also controlling the distance between the folds. Indeed, the distance between the synformal / antiformal folds, and therefore the distance between the long and short folds, determines the deployment method.Advantageously, if the density is higher at a certain point on the periphery, the deployment will be greater, and if it is lower, the envelope will be able to deploy less. It is understood that this results in asymmetry and curvature through a more extensive deployment in the areas with the most folds. Similarly, it is possible to incorporate 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 deploy 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 areas of low bone density that may be present around the implant. It should also be noted that the fluid injection instrument (FEI) 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.

[0045] The terms "cylinder," "cylindrical," or "generalized cylinder" are used interchangeably in this application for ease of disclosure of the invention and all refer to a "generalized cylinder," that is, a three-dimensional shape 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 limit the risk of damage to the tissues into which the implant is inserted. Preferably, this "cylinder" is straight, meaning that its bases are aligned along the generatrix (or height) of the cylinder. Furthermore, since the implant can expand within a 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).

[0046] 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.

[0047] 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.

[0048] In general, the present application relates to an expandable bone implant (1) for human orthopedic surgery for restoring the volume and / or geometry of a bone, by expansion between a folded configuration and a deployed configuration, said implant (1) 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, at least two faces of the implant, for example upper and lower, each comprising a tray (13, 14) for contact with bone tissue, each of the trays comprising a central portion (130, 140) connected, via at least one hinge, to at least one pair of support arms (131, 141) each oriented in opposite directions within each pair,one arm of each pair being connected by a hinge to the distal end (11) while the other arm is connected by a hinge to the proximal end (12), the implant (1) having a central axis (3) or a housing adapted to receive such an axis extending through a sliding sleeve at the proximal end (11) to a traction ring or sleeve at the distal end (12) where said axis is configured to transmit a traction, when actuation by said instrument (A), on the distal end (12) to allow it to be brought closer to the proximal end (11), causing the pivoting of the support arms (131, 141) resulting in the separation of the platforms (13, 14) from each other and, consequently, the expansion of the implant between the folded configuration and the, deployed configuration characterized in that it comprises an envelope enclosing said implant from the proximal end (11) to the distal end (12) and in that: - said envelope is formed by a sheet (10) of biocompatible metal alloy, sealed tightly upon itself; - said sheet (10) has, at least in the folded configuration, a plurality of pairs of folds, each of the pairs 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 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) extends by means of a sealing sleeve securely attached to the flattened and rolled folds of said sheet (10) over the entire periphery of the proximal end (11); - said distal end (12) extends into a socket securely attached, in a watertight manner, to the flattened and rolled folds of said sheet (10) over the entire periphery of the distal end (12) of said implant (1); - said sheet (10) is plastically deformable to allow the expansion of the implant from the folded configuration to the deployed configuration by forming a sealed envelope enclosing the implant and preventing leaks when injecting a fluid into the implant (1) and the envelope.

[0049] In some embodiments, the distance between a synform fold and the next antiform fold is longer than the distance between an antiform fold and the next synform fold, to facilitate the rolling of the folds around the longitudinal axis (L) of the implant in folded configuration.

[0050] In certain embodiments, said sealing sleeve extends said proximal end (11), parallel to the longitudinal axis (L), to a distance which is greater than or equal to that to which the platforms extend from the center of the implant (1)

[0051] In certain embodiments, said sealing sleeve has a through opening whose diameter is greater than or equal to that of the opening of the sliding sleeve, so that these two sealing and sliding sleeves provide an entry into the hollow body of the implant (1) from a conduit of an implanting instrument (A) holding the implant at the proximal end, capable of conveying a fluid to be injected into said implant.

[0052] In certain embodiments, the implant, in deployed position, comprises a median portion between its two ends which has a generalized cylindrical shape of length greater than or equal to that of the plates, with a possible and partial persistence of said folds, said median portion extending, on the side of the proximal end (11), by a truncated conical portion connecting the median portion to the sleeve and, on the side of the distal end (12), by a truncated conical portion connecting the median portion to the 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 (11) and distal (12) ends.

[0053] In some embodiments, said sheet is also plastically deformable from the deployed configuration to the folded configuration, without tearing of the sheet thanks to the thinness of the sheet and in particular thanks to the persistence of the horizontal and rolled folds at the proximal and distal ends, facilitating the reversibility of the expansion.

[0054] In certain embodiments, said central axis (3) is able to cooperate with and / or extends beyond the distal end of an implantation instrument (A) at the level of the proximal end of the implant and having an internal conduit in communication with a conduit (31) formed in said central axis opening into the space formed by the spacing of the platforms, via at least one opening (32) allowing the injection of said fluid into the implant (1).

[0055] In certain embodiments, said sheet (10) is joined at the proximal end (11) with the proximal end of the flat and rolled folds which is welded against the outer wall of said sliding sleeve by a weld (110) and / or joined at the distal end (12) with the distal end of the flat and rolled folds against the outer wall of said traction sleeve by a weld (120).

[0056] In some embodiments, said sheet is compressed around the sleeve at the proximal end (11) and / or around the socket at the distal end (12) by a compression ring (121) keeping the folds lying flat and rolled against the outer wall of said sleeve and / or socket.

[0057] In some embodiments, the folds are, at least in the folded configuration, parallel to the longitudinal axis (L).

[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 number of pleat pairs ranges from 3 to 16, generally from 4 to 2, preferably around 8. However, 3 pleats may sometimes suffice, but the greater the number of pleats, the less material deformation will occur, the lower the risk of tearing, and the easier the deployment. Thus, it is possible to use up to 20 pleats.

[0060] In some embodiments, the sheet (10) has a thickness between 3 and 100 microns, generally between 6 and 50 and preferably between 10 and 30 microns.

[0061] In some embodiments, the sheet (10) is made of titanium alloy.

[0062] In some embodiments, the distance between the folds varies from one lateral face to the other of the implant, so that the shape of the implant in deployed configuration is curved and / or asymmetrical transversely to the longitudinal axis (L).

[0063] In some embodiments, at least some of the support arms are provided in duplicate. Indeed, particularly to limit the risks of uneven expansion of the platforms, due to the opposing forces of the support arms and the external stresses exerted on the implant, it is preferable to provide support arms in duplicate, for example as shown in figures 4A, 4B, 6A and 6B.

[0064] Furthermore, such double arms may include a self-locking mechanism by con- figuration deployed, such as notches made facing each other so as to engage with each other, for example as represented on the enlarged frame of figure 4 A.

[0065] Furthermore, to further improve the reliability and symmetry of the expansion, support arms can be positioned at the ends of the platens instead of simply hinged support arms at the center of the platens, as shown in Figure 7B. This configuration creates deformable parallelograms that maintain parallelism between their sides, resulting in a more reliable expansion.

[0066] Other embodiments are possible with regard to the support arms, including arms which are opposed (cross) only from one face to the other of the implant but which have the same orientation on a given face, as for example shown in Figure 7. However, this type of embodiment is not preferred because of the risks of torsion of the implant during expansion.

[0067] Regarding actuation and locking, it should be noted that the very small diameters of the implants and their central axes are difficult to adapt to threads for screw-type expansion at the implant level. It is advantageous, however, to screw the instrument actuating the expansion, particularly when the expansion involves bringing the support arms closer together. Thus, as known in the prior art, it is possible to use, for example, a split ring housed in a circular reinforcement of the implant and cooperating with notches on the thrust or traction axis. These notches are oriented to allow the axis to pass in only one direction, as shown in Figures 15A, 15, and 15C. In this way, the axis for expanding the platforms can be actuation by successively engaging the notches, which allows the implant to be locked in the deployed configuration.

[0068] On the other hand, the present application also relates to an orthopedic treatment system for damaged bone tissue comprising at least one implant (1), a bone replacement cement and at least one instrument (A) for implanting and injecting (Ac) cement into the implant (1), said system being characterized in that said implant is an implant (1) according to one of the embodiments described in this application.

[0069] 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.

[0070] 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.

[0071] On the other hand, the present application also relates to a method of manufacturing an implant according to one of the preceding claims, characterized in that it comprises: Obtaining an expandable implant with two trays that separate under the effect of bringing the ends of the implant together by means of support arms connecting these ends to the trays; 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, called a star stem (TE), 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 branches of the star; Wrapping the folds of said sheet around longitudinal Tax, Insertion of said expandable implant inside said compressed sheet; Securing said sheet to the socket and sleeve.

[0072] 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).

[0073] 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.

[0074] 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.

[0075] In some embodiments, the implant includes a ring at the proximal end and a base at the distal end, the respective dimensions of which are determined relative to the overall size of the implant so that the foil welded to the ends can unfold when the plates are separated while maintaining a shape that minimizes the risk of tearing the outer shell formed by the foil. Indeed, in its folded configuration, the foil has an equivalent length between these ends of the implant to which the foil is welded, but the shortening of the implant when the plates are separated allows the foil to follow the overall shape of the implant during its unfolding. It is understood that the foil and the rest of the implant, particularly its proximal and distal ends, have complementary dimensions so that the separation unfolds the foil forming the outer shell without tearing it.It should be noted that in certain embodiments, such as those shown in Figures 4B and 12C, the implant can be asymmetrical, allowing for asymmetrical and directional expansion. This is achieved through the shape of the arms and, after the deployment of the platforms, through the shape of the outer shell, which can be designed to accommodate the deformation induced by the implant's expansion as the platforms separate. Furthermore, it is possible to design an outer shell capable of deforming beyond the shape imposed by the implant's deployment in certain embodiments, for example, for expansion of the shell alone, such as laterally (i.e., perpendicular to the direction of expansion caused by the platform separation).

[0076] 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 3B. 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 providing additional security to prevent 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 3B, 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 identical to 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, different from the cement, inside, the compartment between the two sheets can be used as a cooling circuit by circulating a fluid during cement polymerization, thus protecting the tissues from the heat generated during said polymerization.Such a double-leaf implant (1) therefore requires a double cannula comprising two concentric or parallel conduits each opening into one of the spaces provided, as the skilled person will understand from figure 3B without further explanation being necessary.

[0077] Figure 7A depicts a known anterior wing implant in which the deployment arms are arranged asymmetrically on one face of the implant relative to the other, with some arms connecting a single tray to one end while others connect the other tray to the other end. This type of implant is also usable within the scope of the present invention, provided that a sheet is welded to the ends with dimensions sufficient to form a deformable envelope as described in this application.

[0078] Figure 8A represents a perspective view of an expandable implant in a semi-deployed configuration, according to certain embodiments; Figure 8B 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 8C represents a perspective view of this same sheet in a folded configuration.

[0079] Figure 9A 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 9B represents an enlargement of Figure 9A at the distal end showing the distal butt plugging the distal end of the implant.

[0080] Figure 10A 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 10B shows a side view of the 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 10A, 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 10C, 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 10D, 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.

[0081] Figure 11 shows a perspective view of a leaf pre-folding tool for an expandable implant, according to certain embodiments, using a pre-folding plate. This Figure 11 illustrates a preferred embodiment of a tool that allows for alternating long and short folds or alternating symmetrical folds, depending on the shape of the ends of the pre-folding cams (CP) cooperating with a complementaryly shaped star-shaped rod to pre-fold the leaf between the rod and the cams. Indeed, some embodiments of such a tool include ramps (RC) carrying pre-folding cams. The folding cams (CP) may have a first cam angle (CPI) and a second cam angle (CP2) that are different to obtain long and short folds, or two identical cam angles to obtain 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 closed 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 in the case of long and short folds, or with symmetrical points in the case of symmetrical cams and folds, as illustrated respectively in Figures 7B and 7D.

[0082] Figure 12A shows an enlargement of Figure 11. 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 a portion of Figure 11 onto Figure 12A, the interaction between the pre-bending cams and the star-shaped rod is more easily observed.Figure 12C 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.

[0083] Figure 13A shows an example of a sheet folded into a cylinder that has been pre-bonded with symmetrical folds, and Figure 13B 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).

[0084] Figures 14A, 14B, and 14C 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.).

[0085] Figure 15A shows a perspective view of an implant without its leaf according to certain embodiments, and Figure 15B shows the same implant from which the expansion rod has been removed. Figure 15C shows a cross-sectional view of the implant of Figure 15A in which the expansion rod is present. Figure 15A shows an embodiment in which deployment is achieved by a mechanism known from the previous text. As illustrated in Figure 15B, this mechanism includes a notched lock (VC) which con- It has a circumferential groove designed to receive a split ring that acts as a locking clip. This clip engages with a circumferential housing inside the conduit into which the notched lock is inserted. As shown in Figure 15C, pulling on the notched lock causes the split ring to engage with notches in the implant conduit, allowing it to be locked step by step. This locking mechanism engages internal notches within the implant conduit. These notches are preferably asymmetrical to allow only the lock to be withdrawn towards the exit point, thus securing the implant in its deployed position and preventing it from folding under the force exerted by the surrounding tissues.

[0086] 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.

[0087] Detailed list of references in the figures: I implant 10 sheets 10b second sheet II proximal end 11b second ring 101 anti-forming fold 102 synformal fold 110 proximal weld 12 distal end 120 distal weld (watertight connection) 121 Compression fastening (e.g., split ring) An implantation instrument Al 2 distal plug TG internal guide GR external guide PP Pre-bending plate ET star rod CP pre-bending cam CPI first pre-bending cam angle CP2 second pre-bending cam angle RC cam ramp 3 central axis 31 conduit in central tax openings of the central axis conduit first tray second tray central reinforcement of the first tray central reinforcement of the second tray support arm of the first tray support arm of the second tray

Claims

Demands 1. An expandable bone implant (1) for human orthopedic surgery for restoring the volume and / or geometry of a bone by expansion between a folded and an extended configuration, said implant (1) 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, at least two faces of the implant, for example, superior and inferior, each comprising a platform (13, 14) for contact with bone tissue, each platform comprising a central portion (130, 140) connected, via at least one hinge, to at least one pair of support arms (131, 141) oriented in opposite directions within each pair, one arm of each pair being connected by a hinge to the distal end (11) while the other arm is connected by a hinge at the proximal end (12),the implant (1) comprising a central axis (3) or a housing adapted to receive such an axis extending through a sliding sleeve at the proximal end (11) to a traction ring or sleeve at the distal end (12) where said axis is configured to transmit traction, when actuation by said instrument (A), to the distal end (12) to bring it closer to the proximal end (11), causing the pivoting of the support arms (131, 141) resulting in the separation of the platforms (13, 14) from each other and, consequently, the expansion of the implant between the folded and deployed configurations characterized in that it comprises a casing enclosing said implant from the proximal end (11) to the distal end (12) and in that:, - said envelope is formed by a sheet (10) of biocompatible metal alloy, sealed tightly upon itself; - said sheet (10) has, at least in the folded configuration, a plurality of pairs of folds, each of the pairs 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 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) extends by means of a sealing sleeve securely attached to the flattened and rolled folds of said sheet (10) over the entire periphery of the proximal end (11); - said distal end (12) extends into a socket securely attached, in a watertight manner, to the flattened and rolled folds of said sheet (10) over the entire periphery of the distal end (12) of said implant (1); - said sheet (10) is plastically deformable to allow the expansion of the implant from the folded configuration to the deployed configuration by forming a sealed envelope enclosing the implant and preventing leaks when injecting a fluid into the implant (1) and the envelope.

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

3. Implant according to any one of the preceding claims, characterized in that said sealing sleeve extends said proximal end (11), parallel to the longitudinal axis (L), to a distance which is greater than or equal to that to which the platforms extend from the center of the implant (1) 4. Implant according to any one of the preceding claims, characterized in that said sealing sleeve has a through opening whose diameter is greater than or equal to that of the opening of the sliding sleeve, so that these two sealing and sliding sleeves provide an entry into the hollow body of the implant (1) from a conduit of an implanting instrument (A) holding the implant at the proximal end, suitable for conveying a fluid to be injected into said implant.

5. Implant according to any one of the preceding claims, characterized in that the implant comprises, in deployed position, a median portion between its two ends which has a generalized cylindrical shape of length greater than or equal to that of the plates, with a possible and 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 the sleeve and, on the side of the distal end (12), by a frustoconical portion connecting the median portion to the 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.

6. Implant according to one of the preceding claims, characterized in that said sheet is plastically deformable also from the deployed configuration to the folded configuration, without tearing of the sheet thanks to the thinness of the sheet and in particular thanks to the persistence of the horizontal and rolled folds at the proximal and distal ends, facilitating the reversibility of the expansion.

7. Implant according to any one of the preceding claims, characterized in that said central axis (3) is able to cooperate with and / or extends beyond the distal end of an implantation instrument (A) at the level of the proximal end of the implant and having an internal conduit in communication with a conduit (31) formed in said central axis opening into the space formed by the spacing of the platforms, via at least one opening (32) allowing the injection of said fluid into the implant (1).

8. Implant according to any one of the preceding claims, characterized in that said sheet (10) is joined at the proximal end (11) with the proximal end of the horizontal and rolled folds which is welded against the outer wall of said sliding sleeve by a weld (110) and / or joined at the distal end (12) with the distal end of the horizontal and rolled folds which is welded against the outer wall of said traction sleeve by a weld (120).

9. Implant according to any one of the preceding claims, characterized in that said sheet is compressed around the sleeve of the proximal end (11) and / or around the socket of the distal end (12) by a compression ring (121) keeping the folds lying flat and rolled against the outer wall of said sleeve and / or of said socket.

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

11. 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 also in length of the implant or oblique for a curved expansion of the implant.

12. 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.

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 distance between the folds is variable from one lateral face to the other of the implant, so that the shape of the implant in deployed configuration is curved and / or asymmetric transversely to the longitudinal axis (L).

16. Orthopedic treatment system for damaged bone tissue comprising at least one implant (1), a bone replacement cement and at least one instrument (A) for implanting and injecting (Ac) cement into the implant (1), said system being characterized in that said implant is an implant (1) according to one of the preceding claims.

17. System according to claim 16, characterized in that the implantation and cement injection instrument includes means for controlling the pressure and / or aspiration of the cement to fold the implant into a folded configuration if necessary.

18. System according to any one of claims 16 and 17, characterized in that 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.

19. A method for manufacturing an implant according to any one of the preceding claims, characterized in that it comprises: Obtaining an expandable implant with two platforms that move apart under the effect of bringing the ends of the implant together thanks to support arms connecting these ends to the platforms; - Closing the sheet onto itself and welding to form a generalized cylinder; - Insertion of the closed sheet onto a generalized cylindrical matrix having a star-shaped base, called a star stem (TE), the number of points of the star defining the number of pairs of folds of said leaf 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, - Insertion of said expandable implant inside said compressed sheet; Securing said sheet to the socket and sleeve.

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