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 manufacturing method for human orthopedic surgery, for restoring volume and / or geometry of a bone by expansion, wherein at least two faces of the implant each comprise a plate, bringing the distal (12) and proximal (11) ends toward one another generating pivoting of support arms, thereby causing the plates to move away from one another and consequently the implant to expand, characterized in that an expansion sleeve or ring (20) and the proximal end of a central axis (3) of the implant are movable away from one another in order to exert traction on the plates via expansion arms, which generates pivoting of the support arms so as to result in controlled expansion of the implant (1) between the folded configuration and the deployed configuration.

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 objective is achieved by an expandable bone implant for human orthopedic surgery for restoring the volume and / or geometry of a bone, through expansion between a folded and an deployed configuration, said implant comprising a central axis and extending along a longitudinal axis between a proximal end connectable to an implantation instrument to hold the implant and a distal end intended to be inserted first into the bone, at least two faces, for example superior and inferior, of the implant each comprising at least one tray for contact with the bone tissues, each of the trays being supported by at least two support arms, each via a hinge on the central axis and a hinge under the respective tray of each of said support arms; 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 movable from each other to exert traction on the plates, via the expansion arm, which causes a pivoting of said support arms causing the platforms 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.

[0015] According to another feature, it is said expansion ring which is actuable by being able to cooperate, by means of attachment, with a hollow tube for gripping the implant of said implantation instrument, in which an expansion rod passes through the ring, while the central axis 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 central axis to move away from said ring, resulting in an expansion of the implant controlled according to the force of push exerted on the expansion rod.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] According to another particularity, the implant includes 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 with respect to the central axis, to exert homogeneous compression on the bone tissues at the periphery of the implant.

[0022] According to another distinctive feature, the trays are equipped, on their contact surface 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 achieved by notches, ribs, grooves, in the shape of straight or curved blades or chevrons, but also points, etc.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Other features and advantages of the present invention will become clearer upon reading the description of various embodiments below, made with reference to the accompanying drawings, in which: Figure 1A represents a perspective view of an expandable implant according to certain embodiments; Figure IB represents a perspective view of an expandable implant according to another embodiment in folded configuration; and Figure IC represents a perspective view of the implant of Figure IB in deployed configuration; Figure 2A represents a perspective view of an expandable implant in a folded configuration according to certain embodiments and Figure 2B represents a cross-sectional view of the implant of Figure IB; Figure 3A represents a profile view of an expandable implant in deployed configuration and Figure 3B represents a detail of the proximal end of an expandable implant according to certain embodiments; Figures 4A, 4B, 4C and 4D represent profile views of 4 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 from figures 4A, 4B, 4C and 4D but in deployed configuration with their non-parallel platforms; 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 anterior art implant is implanted; Figure 6C shows a perspective view of a vertebra into which is implanted an implant 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 represent respectively a top view, a front view and a side view of a three-platform expandable implant according to certain embodiments; Figures 9A and 9B represent perspective views from the rear and front respectively of an extendable implant according to the embodiments of figures 8A, 8B and 8C; Figures 10A, 10B and 10C represent profile views of vertebrae that have suffered vertebral compression fractures (VCF), respectively at the anterior, medial and posterior levels; Figure 11A represents a perspective view of an expandable implant in deployed configuration and equipped with a lock holding the implant in its deployed configuration, Figure 11B represents a detail of the proximal end of an implant of the type of Figure 11A with the lock outside the implant according to certain embodiments, and Figure 11C represents a detail of the proximal end of an implant according to certain embodiments with another type of lock outside the implant; Figure 12A represents a life in perspective of an implant according to certain embodiments and figures 12B and 12C respectively represent the detail of insets 12B and 12C of figure 12A of the implant.

[0028] This application relates to an implant and an orthopedic surgical system for the treatment of fractured bones and bone tissue in general, as well as a method for manufacturing the implant. The bone implant is preferably a spinal implant, and in particular a vertebral or even intravertebral implant, but other uses are conceivable elsewhere in the spine (intervertebral spines) or in other bony structures where it is necessary to fill a gap resulting from a fracture (the causes of which can be varied, although they generally involve a decrease in bone density). Thus, vertebral compression fractures (VCFs) are a preferred application but are not the only ones that can be treated with the present invention, and those skilled in the art will appreciate the possibilities offered without needing further detail here.Other bones that can be used include the femur or humerus (head), for example, in cases of risk of collapse, and the implant can be placed directly into the spinal canal. Furthermore, the tibial plateau is frequently subject to crushing, and the implants or systems described in this application are useful for restoring height in all types of bone crushing or collapse, for example, in the distal part of the humerus or femur. Moreover, as described, for example, in document EP2921142, expandable implants can be used as bone anchors, and such use is also possible for implants like those described in this application. In this case, the implants will be extended at their proximal end by an elongated body onto which another orthopedic implant can be fixed. of another type or a surgical device for fixing other elements. However, when used as a bone anchor in a vascularized structure, such as a humeral or femoral head, the size of the implant relative to the bone structure should preferably be limited to preserve vascularization and promote bone healing. Certain embodiments with more than two platforms may be more effective in treating long bones of this type by distributing expansion forces over more than two surfaces, thus providing greater stability regardless of the bone type. However, the use of the implant in long bones is not limited to embodiments with more than two platforms, as, depending on the type of fracture, a two-platform implant may still be suitable for use in long bones, as illustrated in Figures 12A, 12B, and 12C.The only notable differences in the treatment of long bones are the length of the implant platforms and, above all, the length of the support arms, which generally varies depending on their position within the medullary canal. In particular, the medullary canal is generally wider at the ends of the bone than in the center, and various designs allow for adaptation to this shape of the medullary canal. This is achieved through the use of support arms (131, 141) of varying lengths to obtain greater or lesser expansion at different points on the implant, as illustrated in Figures 12B and 12C. Thus, with longer support arms (131, 141) at the ends, the implant expansion will be greater at the extremities, which will therefore be positioned at the epiphyses of the long bone, for example. It should be noted that in such cases, the platforms themselves can be articulated in areas where expansion is variable.Such an articulation can naturally consist of a thinning of the plates at suitable places depending on the lengths of the support arms, for example as shown in figures 12B and 12C.

[0029] Similarly, in various embodiments not necessarily involving long bones, the implant has distal support arms of a different length than 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.

[0030] 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 problem, it is preferable not to use cement with the implant described here if the cement is not contained, at least in cases where the fracture is so large that the cement could leak into the surrounding tissues.

[0031] 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.

[0032] 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.

[0033] 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 support arms are not of equal length.

[0034] Furthermore, the present invention makes it possible to control the shape of the implant once deployed, for example as illustrated in Figures 4A, 4B, 4C, 4D, 5A, 5B, 5C and 5D. A fluid injection instrument (Ac) can be provided to fill the implant with a fluid such as bone cement. Such an instrument can be equipped with means to control the injected pressure (a manometer for example) and to determine the resulting volume, in order to effectively control the expansion in the bone tissue.

[0035] Finally, it is understood that the instrumentation proposed in this application in certain This method, using a relatively conventional implant holder (or ancillary device) to hold the implant and insert it into the bone, and a less conventional device to expand it within the bone, also offers the advantage of performing all implantation and stabilization steps with a single instrument in a continuous operation. Indeed, the ancillary device, with its hollow tube for delivering cement through a tube that retains the cement, allows for a quick and efficient surgical procedure. After drilling, the implant is inserted, and without removing the instrument, cement can be injected. The tool can then be 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.

[0036] 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); This proximal end is connectable to a grasping instrument (called an implant holder) and therefore capable of cooperating with it, by means of attachment or physical connection, for example, known to those skilled in the art. Nevertheless, some embodiments provide specific and advantageous attachment means to facilitate grasping the implant by an implant holder and, above all, the release of the implant by an L-shaped movement of the implant holder. Furthermore, by being connectable to the instrument, the implant is generally actuated for its expansion (in particular by injecting a fluid inside and / or by pushing or pulling on an element of the implant), as is widely known in the prior art. Indeed,Many systems include expandable implants that can be actuated when mounted on an implant carrier. This carrier incorporates an actuation mechanism for implant expansion (generally a conduit and / or rod passing through the implant carrier to open into a cavity in the implant and / or cooperate with an implant component that allows for expansion; the actuation typically involves a pushing and / or pulling force). A person skilled in the art will understand from this application that the implant can be defined without further detail regarding the instrument and the actuation mechanism, as these are standard features in the field. The system comprising the implant and the instrument is, of course, fully defined, but that... The implant itself is in fact also well defined in terms of its actuability, independently of the instrument and without unnecessary detail regarding the actuating mechanism (e.g., a sliding rod), 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 a pull (with or without rotation), and this application thus provides sufficient explanation for the implant to be considered sufficiently clearly defined without further reference to the instrument enabling its actuation.Conversely, some embodiments may relate to the instrument itself, through an originality of its elements allowing the grasping of the implant and / or the actuation for the expansion of the implant, and these characteristics then define the instrument independently of the implant since they do not particularly require details on the implant apart from those relating to the function performed by the instrument. Such an implant (1) is preferably 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 able to move away from each other to exert traction on the trays (13, 14, 15), by means of the expansion arms (132, 142, 152), which causes a pivoting of said support arms (131, 141, 151) causing the trays (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 obtained by the fact that the latter are able to cooperate, respectively or inversely, with a hollow tube (Al) 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.

[0037] 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.

[0038] Note 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 2 A, as known in the prior art on deployable implants including other deployment mechanisms like those above and on the contrary for example with support arms which come together for the expansion of the implant.

[0039] It should be noted that the term "central reinforcement" refers to a central axis on which the deployment support arms are articulated. The implant platforms, to which the support arms are also articulated, serve as reinforcement, but primarily as expansion supports, since they act as a pivot point for the joints or as a hinge on one of the platforms. Furthermore, the expansion (i.e., support) arms are advantageously connected directly to the platform to allow the implant's expansion force to be applied and the platforms to be separated directly by acting on them with a force in a single direction.

[0040] In certain embodiments, 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).

[0041] 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).

[0042] In some embodiments, the central axis (3) includes 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).

[0043] 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.

[0044] 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 platforms (13, 14, 15), with hinges at both ends of the support arm (130, 140, 150) for its pivoting.

[0045] 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.

[0046] 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 requirements 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. In some embodiments, double support arms are provided to reinforce the structure. Furthermore, locking means are provided in some cases to prevent the implant from folding.The very small diameters of the implants and their central axes make it difficult to use threads for expansion by screwing directly onto the implant. However, it is advantageous to screw into the instrument that actuates the expansion, particularly when the expansion involves bringing the support arms closer together. Thus, as known in the prior art, it is possible to use, for example, a split ring housed in a circular reinforcement of the implant and cooperating with notches on the thrust or traction axis. These notches are oriented to allow the axis to pass in only one direction, as shown in Figure 11C. In this way, the axis for expanding the platforms can be actuation achieved by successively engaging the notches, which allows the implant to be locked in the deployed configuration.

[0047] 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 this 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 11 A and 11 IB, it is possible to use, for instance, a threaded sleeve configured to fit inside the hollow tube of the implantation instrument (A) holding the implant (and surrounding any fluid injection channel 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 11C).

[0048] Furthermore, the arrangement of the implants in this application provides a significant advantage with regard to the reliability of the expansion. 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 that the arms be provided in duplicate. Copies on each side improve the reliability of the expansion. The implants of this application do not require doubling the arms, but it remains possible to do so, particularly in the case of large implants and / or those intended to support a significant load. Thus, some embodiments include duplicate support arms, at least in one of the arm positions and preferably in each of them, for example as shown in Figure 3A. Furthermore, such duplicate arms may include a self-locking mechanism in the deployed configuration, such as opposing notches that engage with each other, for example as shown for the central support arms (130, 140) in Figure 3A.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] Figure 1A shows a perspective view of an expandable implant in certain embodiments; Figure IB shows a perspective view of an expandable implant in another embodiment in its folded configuration; and Figure IC shows a perspective view of the implant in Figure IB in its deployed configuration. In Figure 1A, it should be noted that the expansion ring has an L-shaped groove allowing the implant to be gripped by a tool comprising a gripping means actuated by a quarter-turn movement complementary to the L-shape, facilitating assembly with the implant carrier and, above all, the release of the implant at the end of the operation.The term quarter turn can be used here to refer to a conventional mechanism, but it is clear that such a method does not necessarily require a 90° rotation and that it can involve more or less, although a significant rotation before releasing the implant is preferable. In Figure IA, it will be noted that the proximal end (11) has a channel allowing cement injection into the implant, and in Figure IB, it will be noted... The central axis (3) also has holes (32) provided to allow cement injected via the proximal end to reach the interior of the axis (3), which is equipped with a central channel (31) opening onto the holes (32). This facilitates the distribution of cement within the implant and, in particular, the space created by the implant's expansion through the spreading of the platforms, as particularly visible in Figure 2B. Figure 2A shows a perspective view of an expandable implant in a folded configuration according to certain embodiments, and Figure 2B shows a cross-sectional view of the implant in Figure 1B. Figure 2A actually represents a variant similar to certain prior art implants with only one platform, 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 platform allows deployment in only one given direction, perpendicular to the longitudinal axis, which can be useful in certain cases. The present design naturally also allows for this type of implementation.

[0054] It should also be noted that the joints between the central axis and the plates in the examples shown, and particularly in Figure 2B, 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 joint 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 for 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.

[0055] Figure 3A shows a side view of an expandable implant in its deployed configuration, and Figure 3B shows a detail of the proximal end of an expandable implant according to certain embodiments. In particular, Figure 3A shows an example of certain embodiments in which each of the support arms, or at least a portion thereof (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 projections that complement the other support 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 gap) is exceeded.

[0056] Figures 4A, 4B, 4C, and 4D show profile views of four expandable implants in a folded configuration, presented in various embodiments with support arms of different lengths. Similarly, Figures 5A, 5B, 5C, and 5D show The profile views of the implants in Figures 4A, 4B, 4C, and 4D are shown respectively, but in their deployed configuration with their non-parallel platforms. In some embodiments, the platforms are articulated on support arms (131, 141) whose lengths vary from one platform 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 surfaces (internal or external).For example, in Figures 4C and 5C, the platforms are concave, meaning that the distance(s) between them at the distal and proximal ends is less than the distance between them at these two extremities. Conversely, in Figures 4D and 5D, the platforms, once deployed, are convex because the distance(s) between them at the proximal and distal ends is less than the distance between the platforms at these two extremities. These different configurations are obtained because the support arms have different lengths along the longitudinal axis, and it is also possible that these lengths differ between the arms of one platform compared to those of 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 from one platform to another, 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 implant platforms (regardless of their number). For example, by taking the upper half of one of figures 4A to 4D or 5A to 5D as one platform and the lower half of another of these figures, it is clear that a large number of combinations are possible, each providing particular advantages depending on the geometry of the structure to be restored.

[0057] Figure 6 shows a top view of a vertebra into which an implant is placed according to various embodiments; Figure 6B shows a perspective view of a vertebra into which an anterior-art implant is placed; while Figure 6C shows a perspective view of a vertebra into which an implant is placed 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. sion and we see that the implant can conform more reliably to the space it fills, thanks to platforms supported to their ends, but also thanks to the envelope which, once filled with cement, will completely fix the expanded implant and the bone structure.

[0058] Figure 7A shows a perspective view of an expandable implant according to a reversed embodiment, and Figure 7B shows a perspective view of a vertebra in which the implant of Figure 7A is implanted using an instrument. Figure 7A shows certain embodiments in which the extension of the implant is reversed compared to other embodiments; that is, the expansion ring (20), instead of being positioned proximally to exert traction on the endplates, is positioned distally to also exert traction on the endplates but towards the distal end by means of a thrust force transmitted through the implant and in particular 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 pressure, while the proximal end (11) is held fixed by an implant holder. The platforms thus separate by means of 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 stress 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, in which only a portion of the central axis (3) and the proximal end, by which the implant was held by the implant holder, remain at the proximal end.The plates are thus deployed forward, limiting the risk of rupture at the proximal end, for example, as shown in Figure 7B. This is particularly relevant in the case of a vertebra where it may be advantageous to avoid applying pressure to the proximal part, which could, for example, be close to a bone wall. In the example 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 rupture.

[0059] 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. Figures 9A and 9B show perspective views from the rear and front, respectively, of an expandable implant according to the embodiments of Figures 8A, 8B, and 8C. Figures 8A, 8B, 8C, 9A, and 9B represent embodiments in which the implant has more than two platforms, and in particular, 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 implant deployment allows for the restoration of a greater number of additional bone structures compared to implants with only two platforms, particularly long bones. The deployment of such types of implants allows for better results. to guarantee the expansion volume obtained in relation 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 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.

[0060] Figures 10A, 10B, and 10C 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.).

[0061] Figure 12A illustrates the life cycle of an implant according to certain embodiments, and Figures 12B and 12C respectively show details of insets 12B and 12C of the implant in Figure 12A. In these embodiments, the implant has a length suitable for restoring the geometry of long bone structures, such as long bones. The example shown in Figures 12 has only two platforms, but it is clear that it could have three or four, and the implant length is designed to allow, for example, intramedullary insertion into a long bone. In such embodiments, the number of expansion arms will vary and they will generally be present only at the ends of the central access port and the implant, since expansion is usually desired close to this point, which is generally intended for placement at the epiphyseal level.However, it is of course possible to have support arms distributed anywhere along the longitudinal axis of the implant. In the case of intramedullary implantation, using support arms only at the ends of the implant allows it to conform to the internal shape of the canal, which generally flares at the epiphyseal ends. Furthermore, notches (133, 143) provided on the platforms at various locations (generally intended to be placed near the epiphyses) allow for bending of the platforms, offering greater local flexibility. In addition, it is possible to use a different number of support arms between the proximal and distal ends, depending on the type of expansion desired.For example, in the case of long bones ending in a head which generally has a medullary canal with a larger diameter than the other end of the long bone, it is possible to plan implants of different lengths and adapted to different types of bone such as the humerus, femur, etc. with adapted diameters, an adapted number of platforms and an expansion providing a final deployed shape that varies according to the type of bone and the desired geometric restoration.

[0062] Figure 11A shows a perspective view of an expandable implant in its deployed configuration, equipped with a lock to hold the implant in this configuration; Figure 11B shows a detail of the proximal end of an implant of the type shown in Figure 11A. with the lock on the outside of the implant according to certain embodiments, and Figure 11C shows a detail of the proximal end of an implant according to certain embodiments with another type of lock on the outside of the implant. In particular, Figures 11A and 11B show 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. Screwing the lock (VV) presses on the central axis (3) to prevent it from moving towards the proximal end and causing the implant to fold, thus locking it in the deployed position.Such a lock is preferably provided with a central hole and possibly distal holes to allow cement injection into the implant, as in some embodiments already described above. Furthermore, for screwing this lock (VV), its proximal end is provided with means for cooperating with a screwing tool, such as peripheral wings shown in Figures 11A and 11B. In Figure 11C, however, the locking mechanism relies on notches. This mechanism includes a notched lock (VC) which contains a circumferential groove adapted to receive a split ring serving as a locking clip. This clip is designed to cooperate with a circumferential housing inside the conduit into which the notched lock is inserted.As shown in Figure 1 IC, pushing on the notched lock causes the split ring to engage with notches in the implant channel, which can thus be locked step by step by the lock against internal notches in the implant channel. These notches are preferably asymmetrical to allow only the lock to be withdrawn towards the exit, thereby securing the implant in its deployed configuration and preventing it from folding under the force exerted by the surrounding tissues.

[0063] 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.

[0064] Detailed list of references in the figures: I implant II proximal end 12 distal end An implantation instrument AC fluid injection instrument The hollow gripping tube A3 expansion rod? 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 tray 141 support arms for the second platform 151 support arms for the third platform 132 expansion arm of the first platter 133 notch of the first platter 142 expansion arm of the second platter 143 notch of the second platter 152 third plateau expansion arms 130 central support arm of the first tray 140 central support arm of the second tray 150 central support arm of the third tray VC notched lock vv screw 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 extended 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 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 removable, to exert traction on the platforms (13, 14, 15), by means of the expansion arms (132, 142, 152), which causes 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.

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 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).

3. Implant according to claim 1, characterized in that it is the proximal end of the central axis (3) that is actuable by being able to cooperate, by means of attachment, with said hollow tube (A1) for 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 thrust 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 thrust force exerted on the expansion rod (A3).

4. Implant according to any one of the preceding claims, characterized in that the platforms are provided, on their contact surface with the bone tissue, with irregularities of shape such as protrusions or, conversely, invaginations to improve the grip of the platforms on the bone tissue.

5. Implant according to any one of the preceding claims, characterized in that the central axis (3) has 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 deliver at least one fluid to 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).

6. 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.

7. 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.

8. Implant according to any one of the preceding claims, characterized in that the support arms at the distal level have a different length from that of the support arms at the proximal level and / or the central support arms.

9. 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.

10. 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.

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

12. System according to claim 11, characterized in that the implantation instrument (A) and cement injection instrument (Ac) includes means for controlling the pressure and / or aspiration of the cement to fold the implant into a folded configuration if necessary.

13. System according to any one of claims 11 and 12, characterized in that 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.

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