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

Abstract

The present invention relates to an implant, a system and a method of manufacture for human orthopedic surgery, at least two faces of the implant each comprising a plate, wherein bringing the distal (12) and proximal (11) ends toward one another generates pivoting of the support arms, thereby causing the plates to move away from each other and, consequently, expansion of the implant, characterized in that an expansion sleeve or ring (20) and the proximal end of a central shaft (3) of the implant are movable away from each other in order to exert traction on the plates, via expansion arms, which causes the support arms to pivot, resulting in a controlled expansion of the implant (1), the implant comprising an envelope formed by a sheet (10) of biocompatible metal alloy, closed on itself in a sealed manner, with folds wound about the longitudinal axis (L), the sheet being plastically deformable.

Description

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

[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 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 porous balloons or inflatable bags as in documents EP1408888 or EP1379185, possibly equipped with support plates as 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 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 the injection of cement. This slows down and complicates the operation and also presents a risk of the device collapsing between the deflation of the balloon and the filling of the stent with cement. 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 po- Porous or non-porous. However, all the 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 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 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 implant for restoring collapsed bone structure.

[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 extended configuration. The implant has a central axis and 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 expansion (notably by injecting a fluid inside and / or by pushing or pulling on an element of the implant), as is widely known from the prior art. Indeed, many systems include expandable implants that can be actuated when mounted on an implant holder that includes an actuation means for expansion. The implant (generally a conduit and / or a rod passing through the implant carrier to open into a cavity of the implant and / or cooperate with a component of the implant that allows its expansion, the actuation generally involving a pushing and / or pulling force). A 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 the actuation, since these are standard mechanisms in the field, and the system comprising the implant and the instrument is of course fully defined. However, the implant alone is also well defined in its ability to be acted upon 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, for example upper and lower, of the implant each having at least one tray for contact with bone tissue, each of the trays being supported by at least two support arms each, by means of a hinge on the central axis and a hinge under the respective tray of each of said support arms; Such an implant (1) is preferably characterized in that: - an expansion sleeve or ring arranged in the same axis as said central axis; - at least two expansion arms each have a hinge connecting them to one end of one of the plates and a hinge connecting them to said expansion sleeve or ring; - said expansion sleeve or ring and the proximal end of the central axis are moved apart to exert traction on the trays, via the expansion arms, which causes a pivoting of said support arms causing the trays to move away from the central axis, so as to result in a controlled expansion of the implant between said folded configuration and said deployed configuration.

[0016] According to another feature, it is said expansion ring which is actuated to cooperate, by means of attachment, with a hollow grasping tube of the implant of said implantation instrument, in which an expansion rod passes through the ring, while the central axis is adapted to cooperate with said expansion rod of said instrument, so that a thrust exerted on said expansion rod sliding inside said hollow tube causes said central axis to move away from said ring, resulting in controlled expansion of the implant according to the thrust force exerted on the expansion rod.

[0017] According to another feature, it is the proximal end of the central axis that is actuable by being able to cooperate, by means of hooking, with said hollow tube for gripping the implant of said implantation instrument, while said expansion sleeve or ring is able to cooperate with said expansion rod of said instrument, so that a push exerted on said expansion rod sliding inside said hollow tube causes said expansion sleeve or ring to move away from said central axis, resulting in an expansion of the implant controlled according to the force of push exerted on the expansion rod.

[0018] According to another feature, the central axis has a conduit suitable for cooperating with said expansion rod which is, on the one hand, hollow and provided with at least one opening at its distal end and, on the other hand, connectable to a fluid injection instrument to deliver at least one fluid to the implant implantation site via the central axis, preferably provided with openings to allow the fluid to flow out along the length of the central axis.

[0019] According to another feature, the support arms of the trays have two arms connected respectively near the proximal and distal ends of their respective trays, to provide support over the entire length of the trays and limit their risks of bending or creep.

[0020] According to another feature, at least one additional central support arm is connected between a central portion of the central axis and a central portion of the trays, with hinges at both ends of the support arm for pivoting.

[0021] According to another feature, the implant has two platforms arranged on either side of the central axis to provide support against damaged bone tissue on either side of the implant, for example to restore height or width.

[0022] According to another feature, the implant has at least one additional platform, the distribution of the platforms around the central axis varying according to their number and / or the needs in terms of surgical treatment, preferably with an equal angular distribution radially relative to the central axis, to exert homogeneous compression on the bone tissues at the periphery of the implant.

[0023]

[0022] According to another feature, the plates are provided, on their surface in contact with the bone tissue, with irregularities in shape such as protrusions or, conversely, invaginations to improve the grip of the plates on the bone tissue. Such grip can be obtained by notches, ribs, grooves, in the form of straight or curved blades or chevrons, but also points, etc.

[0024] 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.

[0025] 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

[0026] 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.

[0027] According to another feature, the implant has, in the 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 being extended, on the side of the proximal end, by a truncated conical portion connecting the median portion to the sleeve and, on the side of the distal end, 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 and distal ends.

[0028] 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, facilitating the reversibility of the expansion.

[0029] 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 separation of the plates, via at least one opening allowing the injection of said fluid into the implant.

[0030] According to another feature, said sheet is secured at the proximal end by a weld fixing the proximal end of the folds lying and rolled against the outer wall of said sliding sleeve and / or secured at the distal end by a weld fixing the distal end of the folds lying and rolled against the outer wall of said traction sleeve.

[0031] 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.

[0032] According to another peculiarity, the folds are, at least in the folded configuration, parallel to the longitudinal axis.

[0033] 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.

[0034] Another characteristic is that the number of ply pairs ranges from 3 to 16, generally 4 to 12, preferably around 8. However, 3 plies can sometimes suffice, but the greater the number of plies, the less material deformation will occur, the less risk of tearing, and the easier the deployment. Thus, it is possible to Allow up to 20 folds.

[0035] 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.

[0036] Another distinctive feature is that the sheet is made of titanium alloy.

[0037] 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.

[0038] 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.

[0039] 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, characterized in that said implant is an implant according to one of the embodiments described in this application.

[0040] 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.

[0041] According to another particularity, the implantation instrument is distinct but complementary to the injection instrument, whose cement injection channel passes through a channel inside the stem of the implantation instrument, which holds the proximal end of the implant by means of its distal end.

[0042] 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 shows a perspective view of an expandable implant according to a certain embodiment without its outer casing; Figure IB shows a perspective view of an implant with its outer casing before folding the distal end of the casing and after folding at this distal end; and Figure IC shows a perspective view of the implant of Figure IB but in its deployed configuration. Figure 2A represents a perspective view of an implant of the type of that in Figure IC but with the envelope cut in its middle part, Figure 2B represents a profile view of an expandable implant in deployed configuration equipped with double support arms and possessing a self-locking mechanism and Figure 2C represents a detail of the proximal end of an implant according to different embodiments; Figures 3A, 3B and 3C represent profile views of vertebrae that have suffered vertebral compression fractures (VCF), respectively at the anterior, midline and posterior level; Figures 4A, 4B, 4C and 4D represent profile views of four expandable implants in folded configuration according to different embodiments, with support arms of different lengths; Figures 5A, 5B, 5C and 5D represent profile views of the implants respectively figures 4A, 4B, 4C and 4D but in deployed configuration with their non-parallel plates; Figure 6A represents a top view of a vertebra in which an implant is implanted according to various embodiments, Figure 6B represents a perspective view of a vertebra in which an implant of the anterior art is implanted and Figure 6C represents a perspective view of a vertebra in which an implant is implanted according to certain embodiments; Figure 7A represents a perspective view of an expandable implant according to a certain inverted embodiment and Figure 7b represents a perspective view of a vertebra in which the implant of Figure 7A is implanted using an instrument; Figures 8A, 8B and 8C respectively represent a top view, a front view and a side view of a three-plateau expandable implant according to certain embodiments; Figure 9A represents a perspective view of an expandable implant in a semi-deployed configuration, according to certain embodiments; Figure 9B 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 9C represents a perspective view of this same sheet in a folded configuration. Figure 1 OA represents a perspective view of an expandable implant in folded configuration with weld lines at the proximal and distal ends, and Figure 10B represents an enlargement of Figure 10A at the distal end. Figure HA 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; Figure 12A represents a perspective view of a sheet pre-folding tool for a plan according to the various embodiment with a pre-folding plate; Figure 13A represents an enlargement of Figure 12, Figures 13B, 13C and 13D represent top views of different embodiments of the pre-bending tool with its star-shaped stem and the implant sheet slid around it; Figure 14A represents a perspective view of a pre-folded sheet using a star-shaped rod such as that of Figure 13D and Figure 14B represents this same sheet folded on itself, according to certain embodiments Figure 14A represents a top view of a vertebra in which an implant is implanted according to various embodiments; Figure 15A represents a perspective view of an expandable implant in deployed configuration and equipped with a lock holding the implant in its deployed configuration, Figure 15B represents a detail of the proximal end of an implant of the type of Figure 15A with the lock outside the implant according to certain embodiments and Figure 15C represents a detail of the proximal end of an implant according to certain embodiments with another type of lock outside the implant.

[0043] 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 manufacturing process. of 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 space left as a result of a fracture (the causes of which can be varied, although they generally involve a decrease in bone density). Thus, vertebral compression fractures (VCF) are a favorite 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 details here. Other bones that can be used include the femur or the humerus (head), for example, in cases where there is a risk of collapse.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.

[0044] Certain embodiments with more than two platforms can be used more effectively for treating long bones of this type by distributing the expansion forces over more than two surfaces, which provides better stability regardless of the type of bone.

[0045] On the other hand, in various embodiments not necessarily involving long bones, the implant has distal support arms that are different in length from the proximal support arms and / or the central support arms, such that the implant in its deployed configuration has platforms that are not parallel to each other. Illustrative and non-limiting examples of such embodiments are shown in Figures 4A, 4B, 4C, and 4D in their folded configurations and in Figures 5A, 5B, 5C, and 5D corresponding to their respective deployed configurations. It is understood that longer proximal arms (Figs. 4A and 5A) result in platforms inclined towards the distal end, while longer distal arms (Figs. 4B and 5B) result in platforms inclined towards the proximal end.Furthermore, it is possible to design platforms that do not remain flat at the end of expansion, which represents a clear advantage of the implant as it can then conform to the anatomical shapes of the bones where it is implanted. Thus, a concave or bi-concave shape (i.e., concave on both faces of the platforms) of the deployed implant can be obtained with central arms (130, 140) shorter than the support arms (131, 141) as in Figures 4C and 5C, while a convex shape (or bi-convex: i.e., convex on both faces of the platforms) as in Figures 4D and 5D.

[0046] 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 remains a major problem, 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 generally practiced in this field). The seal is, of course, relative, and this term is not exhaustive, 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 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, according to 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 provide for a certain porosity of the leaves (10) at least in certain portions of the implant, for example by means of holes of controlled microscopic size and of number and den-. Controlled conditions. In any case, this type of sheet is capable of reversible plastic deformation a sufficient number of times 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, the swelling of the envelope allows the implant to fill 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.

[0047] 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.

[0048] 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.

[0049] 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 others. 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. It should be noted that thinning of the implant trays is also possible, particularly near the joints (hinges) of the support arms, to allow the tray to conform to the desired morphological shape, especially when the arms The supports are not of the same length. 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) which can have any shape, although a circular shape is preferred to simplify manufacturing and limit the risk of damage to the tissues into which it is inserted. Preferably, this "cylinder" is straight, meaning that its bases are aligned along the generatrix (or height) of the cylinder.On the other hand, as the implant can expand in a tissue by conforming to the shape of the space into which it is introduced (by modifying it through the pressure it exerts on these outlets), the shape may not be constant and the two bases of the cylinder may have different shapes (surfaces).

[0050] 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.

[0051] 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.

[0052] 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. Furthermore, 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 12, 13A, 13B and 13C but it is also possible to have a symmetrical pre-folding shape, as shown for example in figures 13D, 14A and 14B, even if these embodiments allow a less advantageous folding than an asymmetrical folding with an alternation of long and short folds.

[0053] 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 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.

[0054] In certain embodiments, said sheet is plastically deformable from the folded to the unfolded configuration, notably through the persistence of the horizontal and rolled folds at the proximal and distal ends, to allow reversibility of the expansion.

[0055] 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 low-density bone volumes 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.

[0056] 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.

[0057] 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 and an deployed configuration, said implant comprising a central axis (3) and 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, for example superior and inferior, of the implant each comprising at least one platform (13, 14, 15) for contact with bone tissue, each of the platforms being supported by at least two support arms (131, 141, 151) each, by means of a hinge on the central axis (3) and a hinge under the respective platform (13, 14, 15) of each of said arms. support (131, 141, 151); characterized in that: - an expansion sleeve or ring (20) arranged in the same axis as said central axis (3); - at least two expansion arms (132, 142, 152) each have a hinge connecting them to one end of one of the plates (13, 14, 15) and a hinge connecting them to said expansion sleeve or ring (20); - said expansion sleeve or ring (20) and the proximal end of the central axis (3) are actuable to cause a separation between said sleeve (20) and said central axis (3), exerting a traction on the platforms (13, 14, 15), via the expansion arms (132, 142, 152), which generates a pivoting of said support arms (131, 141, 151) causing the platforms (13, 14, 15) to move away from the central axis (3), so as to result in a controlled expansion of the implant (1) between said folded configuration and said deployed configuration. The actuation of the sleeve or ring (20) and the central axis (3) is preferably achieved by the fact that they are able to cooperate, respectively or inversely, with a hollow tube (A1) for gripping the implant (1) of an implantation instrument (A) and with an expansion rod (A3) of said instrument (A), this expansion rod (A3) being able to slide inside said hollow tube (Al), to move said sleeve (20) and said central axis (3) away from each other.

[0058] It is understood that, unlike some prior art implants where the expansion structure (frequently with a traction axis) allows two ends of the implant to be brought together and the support arms to be brought together, the implants of the present application are deployed without bringing the support arms together, which avoids having two opposing forces on the same elements, since the force exerted on the expansion arms (132, 142, 152) allows the support arms (131, 141, 151) to be rotated in the same direction, which limits the stresses on the structures and therefore facilitates deployment but also preserves these structures and thus improves the reliability of the implant.

[0059] It should be noted that the implant has at least one platform, and it is therefore possible to have a single platform for expansion on only one side, for example, as shown in Figure 7C, as known in the prior art on deployable implants with other deployment mechanisms like those described above, and conversely, for example, with support arms that move closer together for implant expansion. It should be noted that the term "central reinforcement" is used to designate a central axis on which the deployment support arms are articulated. The implant platforms, on which the support arms are also articulated, thus serve as reinforcement but primarily as support for expansion, since it acts as a bearing for the joints or as a hinge on one of the platforms. Furthermore, it should be noted that the expansion arms (i.e.(support) are advantageously connected to the platform directly to allow the expansion force of the implant to be exerted and the platforms to be separated directly by acting on them by exerting a force in a single direction.

[0060] In certain embodiments, it is said expansion ring (20) which is actuable by being able to cooperate, by means of hooking, with a hollow tube (Al) for gripping the implant (1) of said implantation instrument (A), in which an expansion rod (A3) passes through the ring, while the central axis (3) is able to cooperate with said expansion rod (A3) of said instrument (A), so that a push exerted on said expansion rod (A3) sliding inside said hollow tube (Al) causes said central axis (3) to move away from said ring (20), resulting in an expansion of the implant (1) controlled according to the force of push exerted on the expansion rod (A3).

[0061] In certain alternative embodiments of the preceding ones, it is the proximal end of the central axis (3) which is actuable by being able to cooperate, by means of hooking, with said hollow tube (Al) of grasping the implant (1) of said implantation instrument (A), while said expansion sleeve or ring (20) is able to cooperate with said expansion rod (A3) of said instrument (A), so that a push exerted on said expansion rod (A3) sliding inside said hollow tube (Al) causes said expansion sleeve or ring (20) to move away from said central axis (3), resulting in an expansion of the implant (1) controlled according to the force of push exerted on the expansion rod (A3).

[0062] In certain embodiments, the central axis (3) comprises a conduit (31) adapted to cooperate with said expansion rod (A3), which is, on the one hand, hollow and provided with at least one opening at its distal end and, on the other hand, connectable to a fluid injection instrument (Ac) to convey at least one fluid into the implant implantation site via the central axis (3), preferably provided with openings (32) to allow the fluid to flow out along the length of the central axis (3).

[0063] In some embodiments, the support arms (131, 141, 151) of the platforms comprise two arms connected respectively near the proximal and distal ends of their respective platform (13, 14, 15), to provide support over the entire length of the platforms and limit their risks of bending or creep.

[0064] Implant according to one of the preceding claims, characterized in that at least one additional central support arm (130, 140, 150) is connected between a central portion of the central axis and a central portion of the trays (13, 14, 15), with hinges at both ends of the support arm (130, 140, 150) for its pivoting.

[0065] In some embodiments, two platforms (13, 14) are arranged on either side of the central axis (3) to provide support against damaged bone tissue on either side of the implant, for example to restore height or width.

[0066] In some embodiments, the implant includes at least one additional platform (15), the distribution of the platforms around the central axis (3) varying according to their number and / or the needs in terms of surgical treatment, preferably with an equal angular distribution radially with respect to the central axis, to exert homogeneous compression on the bone tissues at the periphery of the implant.

[0067] In some embodiments, double support arms are provided to reinforce the structure. Furthermore, locking mechanisms are sometimes included to prevent the implant from folding. The very small diameters of the implants and their central axes make it difficult to use threads for screw-in expansion at the implant level, whereas it is advantageous to screw in 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, which are oriented to allow passage of this axis in only one direction, for example, as shown in Figures 15C.Thus, the actuation of the axis for the expansion of the trays can be achieved by successive passage of the notches, which allows the implant to be locked in the deployed configuration.

[0068] Unlike some prior art implants where the expansion structure (often with a traction axis) used to bring the two ends of the implant together and the support arms closer together must remain in place, the implants of the present application are deployed without bringing the support arms together. This advantageously allows the assembly to be locked with a screw lock, eliminating the need for notches that make the task difficult and reduce reliability. Thus, for example, as shown in Figures 15A and 15B, it is possible to use, for instance, a threaded sleeve configured to be placed in the hollow tube of the implantation instrument (A) holding the implant (and surrounding any injection channel). fluid present inside). Such a sleeve then has a thread intended to cooperate with a tapping of the proximal end (11) of the implant and has means of action for screwing or unscrewing (such as radial fins shown in Figure 15B).

[0069] Furthermore, the arrangement of the implants in this application provides a significant advantage with regard to expansion reliability. Indeed, the fact that the support arms are positioned at least at the ends of the platforms (and possibly with one or more reinforcing arms between the ends) allows for the creation of deformable parallelograms that maintain their parallelism between their sides, unlike some anterior-art implants where the support arms are mounted in opposition. This type of anterior-art implant generally requires two sets of arms on each side to improve expansion reliability. The implants in this application do not require two sets of arms, but this remains a possibility, particularly in the case of large implants and / or those intended to support a significant load.Thus, some embodiments include support arms in duplicate, at least in one of the positions of these arms and preferably in each of them, for example as shown in Figure 2B. In addition, such double arms may include a self-locking mechanism in the deployed configuration, such as notches provided opposite each other so as to engage with each other, for example as shown for the central support arms (130, 140) of Figure 2B.

[0070] The present application also relates to an orthopedic treatment system for damaged bone tissue comprising a bone replacement cement and at least one instrument for implanting (A) and injecting cement (Ac) into the implant (1), characterized in that it comprises an implant (1) according to various embodiments.

[0071] In some embodiments, the implantation (A) and cement injection (Ac) instrument includes means for controlling the pressure and / or suction of the cement to fold the implant into a folded configuration if necessary. This type of means is widely known and may, for example, simply be based on a piston actuated in a cylinder, but may include more complex means, as is widely known in the field of this application.

[0072]

[0073] In some embodiments, the implantation instrument (A) is separate but complementary to the injection instrument (Ac) whose cement injection channel passes through a channel inside the stem of the implantation instrument (A) holding the proximal end of the implant (1) by means of its distal end.

[0074] In some embodiments, the implant may include a second sheet (10) surrounding the first sheet, made of the same or a different material, for example, for thermal insulation protecting the tissues from the heat of polymerization. In this case, the ends have an additional ring to secure this second sheet, maintaining a space between it and the first sheet, potentially with an injection port for another fluid between the two. These two sheets can then be folded and rolled simultaneously during manufacturing. These embodiments allow for preforming. of the injection site (by crushing the spongy bone tissue) and allows, for example, the injection of said fluid in two stages for better adjustment of the shape, the resulting temperature in the tissues and / or the polymerization rate of the fluid.

[0075] Some embodiments also relate to 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 (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; - 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.

[0076] 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).

[0077] 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.

[0078] 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 above. 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.

[0079] Figure 1A shows a perspective view of an expandable implant in a certain embodiment without its outer casing. Figure 1B shows two perspective views of an implant with its outer casing: one before folding the distal end of the casing (top), and the other after folding this distal end (bottom). Figure 1C shows a perspective view of the implant in Figure 1B but in its deployed configuration. In Figure 1B, the deployable implant shown has a deformable outer casing. formed by a sheet (10) welded at its proximal end (11) to the sliding sleeve, while its distal end is closed upon itself with the folded and rolled pleats pressed against each other and joined together by a weld, forming a distal closure (F). Preferably, this distal closure (F) can be folded inside the deployable implant by a pushing force represented by an arrow in Figure IB at the top, in order to obtain an implant in which the outer shell does not protrude from the implant body as shown in Figure IB at the bottom, thanks to the applied force. Finally, Figure IC shows a perspective view of the exterior of this same implant once deployed and when the outer shell has been filled, with the closure (F) retaining the pleats at the distal end.

[0080] It should also be noted that the articulations between the central axis and the plates in the examples shown, and particularly in Figure IB, differ depending on the position of the arms relative to the plate. Indeed, due to the constraints related to deployment caused by the spacing of the plates, it is necessary, in the case of flexible hinges, for the indentation (material clearance) allowing the articulation to be larger at the proximal end than at the distal end, because of their different pivot axes. It should also be noted that the hinges shown in these figures of this application are in fact flexible areas, thanks to these indentations or material clearances which allow flexibility in the material used, whether it is inherently flexible (for example, like PEEK, Polyetheretherketone) or not (for example, like titanium alloys).Such flexible hinges require greater material clearance than mechanical hinges, where such clearance is no longer necessary, or even requires additional material thickness to accommodate the axis of the mechanical hinge. Therefore, these flexible hinges are preferred in most cases.

[0081] Figure 2A shows a perspective view of an implant of the type shown in Figure IC, but with the outer shell cut in its midsection. Figure 2B shows a side view of an expandable implant in its deployed configuration, equipped with double support arms and a self-locking mechanism. Figure 2C shows a detail of the proximal end of an implant according to different embodiments. In particular, Figure 2A shows a perspective view with partial transparency (or cross-section) of the outer shell to demonstrate the behavior of the assembly after deployment. Unlike the embodiments shown in Figures 1 and 2, Figures 7A and 7B show perspective views of an implant according to other embodiments in which the expansion ring (or sleeve) (20) is a distal, rather than a proximal, ring on which a thrust is exerted to cause the spreaders to separate by pivoting the support arms.In this type of embodiment, the shell is also welded to the proximal end (11) at the level of the ring by which the implant can be held by an implant carrier, while at the distal end the shell can either be welded to the ring (20) or left free with a distal closure (F) as in other embodiments. However, it is preferable to weld the distal end of the shell to the ring (20). since it is not possible to fold the distal closure (F) as in the other modalizations because there is no space between the support arms as in these other embodiments.

[0082] Figure 2B illustrates an example of certain embodiments in which each of the support arms, or at least part of the support arms (130, 140, 131, 141), is duplicated into pairs of adjacent arms and could be tripled in other embodiments. Furthermore, some of the support arms (the central arms (130, 140) in this example) have complementary projections to the other arm of the same pair, such that in the deployed configuration, the two projections butt against each other to prevent the implant from folding once a certain expansion value (a spacing) is exceeded.

[0083] Figures 3A, 3B, and 3C show profile views of vertebrae with vertebral compression fractures (VCFs) at the anterior, midline, and posterior levels, respectively. 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.).

[0084] Figures 4A, 4B, 4C, and 4D show profile views of four expandable implants in a folded configuration according to different embodiments with support arms of varying lengths. Similarly, Figures 5A, 5B, 5C, and 5D show profile views of the implants in Figures 4A, 4B, 4C, and 4D, respectively, but in an extended configuration with their trays not parallel. In some embodiments, the trays are articulated on support arms (131, 141) whose lengths vary from one tray to the other for asymmetrical expansion. It is understood that Figures 4 and 5 represent non-limiting examples of particularly advantageous embodiments in which the support arms have different lengths depending on their position along the longitudinal axis.Thus, for example, in Figures 4a and 5a, the platforms, once the implant is deployed, allow for kyphosis in the case of vertebral implantation, because the distance between the platforms distally is less than the distance between the platforms proximally, while Figures 4B and 5B represent examples in which the distance between the platforms distally is greater than that proximally. Furthermore, Figures 4C, 5C, 4D, and 5D represent other particularly advantageous and novel embodiments in which the platforms, during deployment, can adopt a different shape from their folded position, thanks to their flexibility or possible notches distributed on at least one of their faces (inner or outer).For example, in Figures 4C and 5C, the plates are concave, meaning that the distance(s) between them at the distal and proximal levels is less than the distance between these two extremities. Conversely, in Figures 4D and 5D, the plates, once deployed, are convex because the distance(s) between them at the proximal and distal extremities are greater. is less than (or are less than) the distance between the platforms at these two ends. These different configurations are obtained because the support arms have different lengths along the longitudinal axis, and it is also possible for the lengths of the arms on one platform to differ from those on the other platform. Furthermore, in embodiments where the support arms have variable lengths depending on their position along the longitudinal axis, it is also possible to have different lengths between the platforms, for example, to obtain a deployed implant where one platform is concave and the other convex. It is clear that numerous combinations are thus possible for the various platforms of the implant (regardless of their number).For example, by taking the upper half of one of the figures 4A to 4D or 5A to 5D for a platform and the lower half of another of these figures, we understand that we can have a large number of combinations, each providing particular advantages depending on the geometry of the structure to be restored.

[0085] Figure 6A shows a top view of a vertebra into which an implant is implanted according to various embodiments, Figure 6B shows a perspective view of a vertebra into which an anterior-art implant is implanted, and Figure 6C shows a perspective view of a vertebra into which an implant is implanted according to certain embodiments. These figures illustrate how the implant can be placed in a vertebral body for the treatment of a vertebral compression fracture, and demonstrate that the implant can conform more reliably to the space it fills, thanks to platforms supported to their ends, and also thanks to the casing which, once filled with cement, will completely fix the expanded implant and the bone structure.

[0086] Figure 7A illustrates certain embodiments in which the implant extension is reversed compared to other embodiments. In this embodiment, the expansion ring (20), instead of being positioned proximally to exert traction on the trays, is positioned distally to also exert traction on the trays, but towards the distal end, through a pushing force transmitted via the implant, specifically through the central axis. In these embodiments, the proximal end (11) is traversed by a channel through which an instrument can pass to the expansion ring (20) at the distal end to exert a pushing force, while the proximal end (11) is held fixed by an implant holder. The trays are thus moved apart by the pivoting of the support arms (131, 141) relative to the central axis, in a movement directed towards the distal end.These embodiments can be particularly advantageous, especially when it is preferable to limit the forces exerted on the bone tissue at the proximal end and to minimize the implant's size at the proximal end. Indeed, this results in an implant that extends towards the distal end, leaving only a portion of the central axis (3) and the proximal end by which the implant was held by the implant carrier at the proximal end. The platforms thus extend forward, limiting the risk of breakage at the proximal end, for example, as shown in Figure 7B in the case of a vertebra where it may be advantageous not to exert pressure on the proximal part. For example, it could be located near a bone wall. In the example shown in Figure 7B, the implant is deployed by applying pressure with a pivoting of the plates towards the distal end, thus preserving the posterior wall of the vertebral body and limiting the risk of breakage. Figure 7C, on the other hand, represents a variant similar to certain prior art implants with only one plate, but with the pivoting arm mechanism in the same direction, a concept common to most of the embodiments detailed in this application. This type of mechanism with a single plate therefore allows deployment in a single given direction perpendicular to the longitudinal axis, which can be useful in certain cases. The present application naturally also allows for this type of embodiment, as it is sufficient for the shell to be welded to the proximal end (11).

[0087] Figures 8A, 8B, and 8C respectively show a top view, a front view, and a side view of a three-platform expandable implant according to certain embodiments. In particular, Figures 8A, 8B, and 8C represent embodiments in which the implant has more than two platforms, and notably, in these examples, a third platform. However, it is clear that the invention can also cover four or more platforms, but generally, three or four platforms are sufficient since the three-dimensional deployment will generally be satisfactory with such configurations. In these embodiments, it is clear that the deployment of the implant allows for the restoration of a number of additional bone structures compared to implants with only two platforms, and in particular, long bones.The deployment of such implants allows for a better guarantee of the expansion volume achieved compared to the desired volume, whether the implant is completed by cement injection or not (and in particular by a casing retaining the injected cement volume or not). Furthermore, as mentioned above, the use of support arms of different sizes allows for the creation of trays with various shapes once deployed, for example, a concave upper tray and two flat lateral trays, either straight, inclined, or any combination of these configurations: flat and straight, flat and inclined, or concave or convex.

[0088] Figure 9A represents a perspective view of an expandable implant in a semi-deployed configuration, according to certain embodiments; Figure 9B 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 9C represents a perspective view of this same sheet in a folded configuration.

[0089] Figure 10A 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 10B represents an enlargement of Figure 10A at the distal end showing the distal butt plugging the distal end of the implant.

[0090] Figure 11A shows a perspective view of a folding guide tool for a sheet of an expandable implant according to certain guided embodiments using a guide tube, and Figure 11B shows a side view of this same tool with the folded sheet, enlargements 5C and 5D showing side views of the overlap of The sheet at its closure point is shown in two different embodiments. To obtain a sheet (10) folded back on itself into a cylinder shape, 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 having a conduit to receive the folded sheet as illustrated, for example, in Figure 11 A, or an external roller preferably movable in a way that complements 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 internal and external guide allows the two edges (or ends) of the sheet (10), initially rectangular and curved, 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 1 IC. However, it is possible to make two folds in opposite directions on each of these two edges of the sheet to obtain interlocking folds, for example as shown in Figure 11D. This facilitates welding, notably by limiting the risk of puncturing the sheet, and / or improves the reliability and stability of the implant, particularly during its subsequent deployment.

[0091] Figure 12 shows a perspective view of a pre-folding tool for expandable implants, according to certain embodiments, using a pre-folding plate. This figure 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 (PFs). These cams cooperate with a star-shaped rod of complementary shape to pre-fold the leaf between the rod and the cams. Indeed, some embodiments of such a tool include ramps (RCs) carrying pre-folding cams (PFs). These cams may have a first cam angle (PC) and a second cam angle (PC2) 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., crush) and pre-fold the sheet (10) previously closed on itself into a cylindrical shape. For this, this sheet (10) is inserted onto a star-shaped rod (TE) whose cross-section has a star shape with asymmetrical branches in the case of long folds and short folds or with symmetrical branches in the case of cams and symmetrical folds, as illustrated respectively in figures 7B and 7D.

[0092] Figure 13A shows an enlargement of Figure 12. 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 12 in Figure 13A, it is easier to observe the interaction between the pre-bending cams and the star-shaped rod. Figure 13C shows an alternative embodiment in which the star-shaped rod has branches whose dimensions The siones vary on 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 asymmetrical shape which it will also retain once unfolded.

[0093] Figure 14A shows an example of a sheet folded into a cylinder that has been pre-bonded with symmetrical folds, and Figure 14B 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).

[0094] Figure 15A shows a perspective view of an expandable implant in its deployed configuration, equipped with a lock that maintains the implant in this configuration. Figure 15B shows a detail of the proximal end of an implant of the type shown in Figure 15A, with the lock located outside the implant, according to certain embodiments. Figure 15C shows a detail of the proximal end of an implant, according to certain embodiments, with a different type of lock located outside the implant. In particular, Figures 15A and 15B represent embodiments in which the implants, once deployed, can be locked by a screw lock (VV). In such embodiments, the proximal end (11) has a threaded channel into which a screw lock (VV) can be inserted, with a thread provided on its periphery to cooperate with this thread.The locking mechanism (VV) applies pressure to the central axis (3), preventing it from moving towards the proximal end and causing the implant to fold, thus locking it in the deployed position. This type of locking mechanism preferably has a central hole and possibly distal holes to allow cement injection into the implant, as in some embodiments already described above. Furthermore, for tightening this locking mechanism (VV), its proximal end is equipped with means for cooperation with a tightening tool, such as peripheral wings shown in Figures 15A and 15B. In Figure 15C, however, the locking mechanism relies on notches.This mechanism includes a notched lock (VC) with a circumferential groove designed to receive a split ring that acts as a locking clip. This clip engages with a circumferential recess inside the conduit into which the notched lock is inserted. As shown in Figure 15C, pushing on the notched lock causes the split ring to engage with notches in the implant conduit, allowing it to be locked incrementally by the lock against internal notches within the implant conduit. These notches are preferably asymmetrical to allow only the lock to be withdrawn towards the exit, thus securing the implant in its deployed configuration and preventing it from folding under the force exerted by the surrounding tissues.

[0095] In some embodiments, the implant may include a second leaf (10b) in- The first sheet is wrapped around the first sheet, in the same or a different material, to form a double layer, for example as shown in Figure 10C. Such a double layer can offer many different advantages, including thermal insulation to protect the tissues from the heat of polymerization (for example, through a heat-limiting fluid) or simply to ensure additional security by preventing cement leakage if one of the sheets tears. In this case, at least one end of the implant, particularly the proximal end (11), may have an additional ring or base concentric with the first ring or base, or, for example as shown in Figure 10C, a double ring, to secure this second sheet (10b) while maintaining a space between it and the first sheet (10). However, it is also possible to join them together at the ends.In the case of two sheets spaced further apart, it is possible to provide an injection inlet between the two sheets (10, 10b) for a fluid different from or identical to the first, for example, using spacers between the first proximal ring (11) and the second ring (11b) that are concentric and thus form a conduit with an annular cross-section between them, for the injection of this second fluid (such as a lubricant that improves the sliding of one sheet relative to the other and thus facilitates unfolding). These two sheets can then be folded and rolled simultaneously or successively during manufacturing.These embodiments allow for pre-shaping of the injection site (by compressing the cancellous bone tissue) and enable, for example, the injection of the fluid in two stages 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). Such a double-leaf implant (1) therefore requires a double cannula comprising two concentric channels, each opening into one of the spaces created by each of the leaves, via the second proximal ring (11, 11b), as those skilled in the art will understand from Figure 10C without further explanation.

[0096] 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.

[0097] 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) 3 central axis 31 leads along the central axis 32 openings in the central axis conduit 13th first plateau 14 second plateau 15 third plateau 20 expansion ring 131 support arms for the first platform 141 support arms for the second platform 151 support arms for the third platform 132 expansion arms of the first plateau 142 second plateau expansion arms 152 third plateau expansion arms 130 central support arms of the first platform 140 central support arms of the second platform 150 central support arms of the third platform An implantation instrument AC fluid injection instrument The hollow gripping tube Al 2 distal plug A3 expansion rod TG internal guide GR external guide PP Pre-folding plate AND star-shaped stem CP pre-folding cam CPI first pre-bending cam angle CP2 second pre-bending cam angle RC cam ramp VV screw lock VC notched lock

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 deployed configuration, said implant comprising a central axis (3) and 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, for example superior and inferior, of the implant each comprising at least one platform (13, 14, 15) for contact with the bone tissues, each of the platforms being supported by at least two support arms (131, 141, 151) each, by means of a hinge on the central axis (3) and a hinge under the respective platform (13, 14, 15) of each of said support arms (131, 141, 151); characterized in that: - an expansion sleeve or ring (20) arranged in the same axis as said central axis (3); - at least two expansion arms (132, 142, 152) each have a hinge connecting them to one end of one of the plates (13, 14, 15) and a hinge connecting them to said expansion sleeve or ring (20); - said expansion sleeve or ring (20) and the proximal end of the central axis (3) are movable from each other to exert traction on the platforms (13, 14, 15), via the expansion arms (132, 142, 152), which causes a pivoting of said support arms (131, 141, 151) resulting in the platform (13, 14, 15) moving away from the central axis (3), so as to result in a controlled expansion of the implant (1) between said folded configuration and said deployed configuration; and 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 horizontal 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 it is said expansion ring (20) ) which is actuable by being able to cooperate, by means of attachment, with a hollow tube (Al) for gripping the implant (1) of said implantation instrument (A), in which an expansion rod (A3) passes through the ring, while the central axis (3) is able to cooperate with said expansion rod (A3) of said instrument (A), so that a push exerted on said expansion rod (A3) sliding inside said hollow tube (Al) causes said central axis (3) to move away from said ring (20), resulting in an expansion of the implant (1) controlled according to the force of push exerted on the expansion rod (A3).

3. Implant according to claim 1, characterized in that it is the proximal end of the central axis (3) which is actuable by being able to cooperate, by means of hooking, with said hollow tube (Al) of grasping the implant (1) of said implantation instrument (A), while said expansion sleeve or ring (20) is able to cooperate with said expansion rod (A3) of said instrument (A), so that a push exerted on said expansion rod (A3) sliding inside said hollow tube (Al) causes the expansion sleeve or ring (20) to move away from said central axis (3), resulting in an expansion of the implant (1) controlled according to the force of push exerted on the expansion rod (A3).

4. Implant according to any one of the preceding claims, characterized in that the central axis (3) comprises a conduit (31) adapted to cooperate with said expansion rod (A3) which is, on the one hand, hollow and provided with at least one opening at its distal end and, on the other hand, connectable to a fluid injection instrument (Ac) to convey at least one fluid into the implant implantation site via the central axis (3), preferably provided with openings (32) to allow the fluid to flow out along the length of the central axis (3).

5. Implant according to any one of the preceding claims, characterized in that the support arms (131, 141, 151) of the trays comprise two arms connected respectively near the proximal and distal ends of their respective tray (13, 14, 15), to provide support over the entire length of the trays and limit their risks of bending or creep.

6. Implant according to any one of the preceding claims, characterized in that at least one additional central support arm (130, 140, 150) is connected between a central portion of the central axis and a central portion of the trays (13, 14, 15), with hinges at both ends of the support arm (130, 140, 150) for its pivoting.

7. Implant according to any one of the preceding claims, characterized in that it comprises two platforms (13, 14) arranged on either side of the central axis (3) to provide support against damaged bone tissue on either side of the implant, for example to restore height or width.

8. Implant according to any one of claims 1 to 6, characterized in that it comprises at least one additional platform (15), the distribution of the platforms around the central axis (3) varying according to their number and / or the needs in terms of surgical treatment, preferably with an equal angular distribution radially with respect to the central axis, to exert homogeneous compression on the bone tissues at the periphery of the implant.

9. Implant according to any one of the preceding claims, 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 next synform fold, to facilitate the rolling of the folds around the longitudinal axis (L) of the implant in folded configuration.

10. 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) 11. 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.

12. Implant according to any one of the preceding claims, characterized in that it 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.

13. 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 thanks to the persistence of the horizontal and rolled folds at the proximal and distal ends, facilitating the reversibility of the expansion.

14. 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).

15. 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), while the distal end of the sheet (10) is either closed on itself with its horizontal and rolled folds crushed in contact with each other and joined together by a weld forming a distal closure (F), 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 (20) by a weld (120).

16. Implant according to any one of the preceding claims, characterized in that 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 of said socket.

17. 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).

18. 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.

19. 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.

20. 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.

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

22. 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).

23. 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), characterized in that said implant (1) is an implant (1) according to one of the preceding claims.

24. System according to claim 23, 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.

25. System according to any one of claims 23 and 24, 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.

26. 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 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 tax, - Insertion of said expandable implant inside said compressed sheet; Securing said sheet to the socket and sleeve.

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