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, for restoring the volume and / or geometry of a bone by expansion, at least two faces of the implant each comprising a plate having at least one pair of support arms (131, 141), 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: - at least two other faces of the implant are covered in a sealed manner by at least one sheet (10) per face, made of biocompatible metal alloy, - the sheet (10) is plastically deformable in order to allow the expansion of the implant, the total surface area of the sheet being greater than or equal to the lateral surface area of the implant in 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 exist using mesh-structure implants made of shape-memory metal. This metal is constrained into a folded shape for insertion into bone tissue and is capable of spontaneous expansion upon release of the constraint and / or under the influence 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 results in increased costs due to the need for multiple different implants to cover various pathological cases, particularly given 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 correct the collapsed bone structure, or at least provides a limiting force.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 for restoring the volume and / or geometry of a bone, by an expansion between a folded configuration and a deployed configuration, said implant 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 of the implant, for example superior and inferior, each comprising a tray for contact with the bone tissues, each of the trays comprising a central portion connected, via at least one hinge, to at least one pair of support arms, each oriented in opposite directions within each pair, one arm of each pair being connected by a hinge to the distal end while the other arm is connected by a hinge to the proximal end,the implant comprising a central axis or a housing suitable for receiving such an axis extending through a sliding sleeve at the proximal end to a traction ring or sleeve at the distal end where the axis is configured to transmit traction, when actuation by said instrument, to the distal end to enable it to be brought closer to the proximal end, causing the pivoting of the support arms resulting in the separation of the platforms from each other and, consequently, the expansion of the implant between the configuration, folded and deployed configuration, the implant is characterized in that: - at least two other faces of the implant, between those containing the platforms, are covered with at least one sheet per face, made of a biocompatible metal alloy, and hermetically bonded to the central portions under the platforms, to the lateral faces of the arms and to the lateral faces of the proximal and distal ends, - said sheet is plastically deformable to allow expansion of the implant and has, at least in the folded configuration, a plurality of antiformed folds, called convex, and synformed folds, called concave, said folds being laid one on top of the other in the folded configuration, the total surface area of ​​said sheet being greater than or equal to the lateral surface area of ​​the implant in the deployed configuration so as to form a sealed compartment suitable for receiving a fluid inside the cavity obtained by the expansion of the implant

[0015] According to another feature, 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 folding of said sheet onto the surface of the lateral faces of the implant in folded configuration.

[0016] According to another peculiarity, the said sheet on each lateral face of the implant has, in the deployed position, a shape substantially like a diamond, with a permanent persistence of at least part of the folded folds near the proximal and distal ends.

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

[0018] 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, said instrument having an internal conduit in communication with a conduit provided within said central axis and opening into the space provided by the spacing of the plates, by at least one opening allowing the injection of said fluid into the implant.

[0019] According to another feature, joined to a lateral face of the proximal end with the proximal end of the flat and folded folds which is welded against the outer wall of said sleeve by a weld and / or joined to a face of the distal end with the distal end of the flat and folded folds which is welded against the outer wall of said sleeve by a weld.

[0020] According to another peculiarity, the folds are, at least in the folded configuration, parallel to the longitudinal axis.

[0021] According to another characteristic, the number of folds is between 4 and 16, generally 6 to 12, preferably around 8.

[0022] 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.

[0023] Another distinctive feature is that the sheet is made of titanium alloy.

[0024] Another distinctive feature is that the distance between the folds varies from one lateral face of the implant to the other, resulting in an asymmetrical shape of the implant in its deployed configuration. transversely to the longitudinal axis.

[0025] 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.

[0026] This goal is achieved by an orthopedic treatment system for damaged bone tissue comprising an implant, a bone replacement cement and at least one instrument for implanting and injecting cement into said implant, said system being characterized in that said implant is an implant according to one of the embodiments described herein.

[0027] 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.

[0028] According to another peculiarity, the implantation instrument is distinct but complementary to the injection instrument, the cement injection channel of which passes through a channel inside a hollow stem of the implantation instrument configured to hold the proximal end of the implant at the distal end of said hollow stem.

[0029] Another objective of this application is to overcome at least some of the drawbacks of the prior art by proposing a method for manufacturing a surgical implant that is easy to use and allows for effective stabilization of bone tissue.

[0030] This goal is achieved by a method for manufacturing an implant according to the invention, said method being characterized in that it comprises: a) Obtaining an expandable implant with two trays that separate under the effect of bringing the ends of the implant together by means of support arms connecting these ends to the trays; b) Inserting a sheet of biocompatible metallic material between two racks provided with triangular profile grooves to imprint folds in the sheet; c) Folding the folds one on top of the other, to obtain a folded sheet; d) Placing said folded sheet on one lateral face of the implant; e) Securing said sheet to said lateral face; f) Repeating steps b) to e) for the other face of the implant.

[0031] Other features and advantages of the present invention will become clearer upon reading the description of various embodiments below, made with reference to the accompanying drawings, in which: Figures 1: Figure 1A represents a perspective view of an expandable implant in its folded configuration, according to certain embodiments, and Figure IB represents a perspective view of the same implant in its deployed configuration; Figures 2: Figure 2A represents a perspective view of an expandable implant from which the sheet has been removed and showing the weld line of this sheet and Figure 2B represents the same implant in which the sheet is present and the weld line is shown in dotted line; Figures 3: Figure 3A shows a transparent view of an expandable implant according to certain embodiments, with section planes BB and CC of the figures respectively 3B and 3C which represent cross-sectional views, respectively according to the section planes BB and CC of figure A and each an enlargement showing the weld line of the sheet on the implant in these section planes, according to certain embodiments; Figures 4: Figure 4A represents a perspective view of an expandable implant in a folded configuration and without its leaf, according to certain embodiments, and Figure 4B represents the same implant as that of Figure 4A but in an deployed configuration and Figure 4C represents an expandable implant with a leaf on only one of its faces; Figures 5: Figure 5A represents a profile view of a pre-folding rack for expandable implants according to certain embodiments and Figure 5B represents a profile view of a pre-folding rack according to other embodiments and Figure 5C represents a profile view of an expandable implant with double support arms according to certain embodiments; Figures 6: Figure 6A represents a cross-sectional view of an expandable implant carried by an implantation instrument and with an enlargement showing details of the double support arms with a self-locking mechanism; Figure 6B represents a cross-sectional view of a vertebra in which an expandable implant is implanted according to other embodiments; Figures 7: Figure 7A represents a top view of a vertebra in which an implant is implanted according to various embodiments, Figure 7B represents a perspective view of a vertebra in which an anterior art implant is implanted and Figure 7C represents a perspective view of a vertebra in which an implant is implanted according to certain embodiments; Figures 8: Figure 8A represents a perspective view of an implant according to certain embodiments and Figure 8B represents a perspective view of an implant according to other embodiments; Figures 9: Figures 9A, 9B and 9C represent profile views of vertebrae that have suffered vertebral compression fractures (VCF) at the anterior, medial and posterior levels respectively; Figures 10: Figure 1 OA represents a perspective view of an implant without its leaf according to certain embodiments and Figure 10B represents the same implant from which the expansion rod has been removed and Figure 10C represents a cross-sectional view of the implant of Figure 1 OA in which the expansion rod is present.

[0032] 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. Thanks to the present invention, the possibilities offered by the person skilled in the art will be readily apparent without further detail. Other bones that can be used include the femur or humerus (head), for example, in cases of risk of collapse. Furthermore, the tibial plateau is frequently subjected to crushing, and the implants or systems of 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 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 type of orthopedic implant 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.

[0033] Some embodiments involve injecting a fluid (e.g., "bone cement," generally based on a polymer such as PMMA, which is well-known to those skilled in the art, so no details about the cement will be provided here). Once positioned, the implant can be stabilized by such a cement injection. However, since cement leakage is a major problem in this field, various embodiments propose containing the cement within a sealed envelope. The volume of this envelope after injection can be controlled by its structure and material, depending on the injected pressure (and the configuration of the bone tissue, preferably assessed beforehand, as is common practice in this field). The seal is, of course, relative, and this term is not a limiting one, since the level of sealing is actually adapted to the viscosity of the cement at the time of injection.Certain embodiments allow, in particular, for homothetic swelling of the envelope thanks to the (relative) flexibility of the biocompatible metallic sheet (10). This material is generally a titanium alloy obtained in the form of a very thin sheet, preferably by lamination for a controlled surface finish and thickness, in particular a thickness between 3 and 100 microns, generally between 6 and 50, and preferably between 10 and 30 microns. Generally speaking, the present invention uses at least one sheet (10) of biocompatible metal or a biocompatible metal alloy, such as titanium or its alloys, particularly with nickel or other metals, but also nitinol or stainless steel or their alloys.Advantage is taken of recent techniques for obtaining very thin sheets of such metals, particularly with a thickness of less than 50 or even 40 µm, which makes it possible to obtain relatively flexible and elastic sheets, but above all, whose plastic deformation can be used reversibly without reaching their tearing limit, by creating folds arranged longitudinally on the implant. In particular, it is possible to provide a maximum deployed volume that is greater than the volume required for the desired applications so that this limit is never reached and it is possible to fold and redeploy the implant, even several times (para. (For example, in the event of incorrect implant placement) without risk of tearing and uncontrolled 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 and deployed volumes, 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 be advantageous to administer molecules through such a controlled release of this fluid. Thus, various embodiments incorporate a certain porosity in the sheets (10), at least in certain portions of the implant, for example, through microscopically sized holes of controlled number and density. In any case, this type of sheet is capable of reversible plastic deformation a number of times sufficient for the intended application, since it notably offers the possibility of retracting the envelope formed by the sheet in case of a problem (biocompatibility and tear resistance). Indeed, generally, controlling the cement dosage allows monitoring of the fifteen minutes of polymerization during which it is possible to retract the envelope and aspirate the cement.On the other hand, through cement injection and the swelling of the shell, the implant fills the spaces in the damaged tissues according to the compressive forces and bone resistance relative to the hydraulic pressure provided during the cement injection. From such a sheet, it is necessary to obtain a closed structure, which requires folding the sheet over itself and locking it in position. To achieve this, a weld (or a bond or a braze, these terms are not exhaustive) can be made between two overlapping edges or on edges with interlocking folds, to facilitate and strengthen the weld. Some designs therefore incorporate closure by welding from the outside, a simplified and stronger process thanks to the layering of components at these complementary folds.

[0034] Various embodiments allow for the creation of an expandable implant with very small dimensions in its folded configuration while ensuring a satisfactory volume in its deployed configuration. Thus, the passage required for insertion of the implants described in this application is generally smaller than that of known implants, while the expansion is greater than that of these known implants. Indeed, the folded diameter or volume is smaller than the deployed diameter by a factor of between 3 and 20, generally 3 to 8, preferably 4 to 7. This ratio naturally depends on the amount of cement injected, and some embodiments take advantage of the fact that the implant can be designed to expand beyond what is necessary, notably by retaining folds in the deployed configuration. Therefore, the implant volume will be determined based on the reduced size required for insertion into the bone tissue and thus with reference to the folded volume.However, different volumes are planned for the deployed configuration, since the number of folds and the length of the folds allows the deployment ratio to be increased.

[0035] 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.

[0036] 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.

[0037] The term "hinge" is used here in its functional sense, without implying any structural limitation, and can in fact refer to mechanical hinges, even if they are preferably formed (as illustrated in the non-limiting examples in the figures) by thinning (or narrowing, material removal) of elements such as support arms or other components. Thus, a hinge is in fact a point or zone of articulation, since it is known in the field that it is generally safe to incorporate such pivoting mechanisms for implants because the materials used in their construction are suitable for this type of articulation.

[0038] The terms antiform fold, also called convex, and synform fold, also called concave, are used by analogy with the definitions of folds in many technical fields, including geology, but it should be understood that convexity here is defined in relation to the exterior of the implant. An antiform or convex fold is therefore a fold that folds the material inwards, while an antiform fold folds the material outwards. The succession of these two types of folds allows for minimizing the folded volume. Furthermore, some designs incorporate long and short folds in succession to facilitate rolling and / or compaction, limiting the overlap of material in the folded configuration. It should also be noted that the number of folds is not limited and, on the contrary, allows for maintaining the irregularity or the actual shape of the implant during deployment, which also offers advantages, particularly in terms of stabilization.Furthermore, it remains preferable to ensure an equal distribution of surface areas between the folds for uniform deployment, but the invention also envisages other applications, particularly folds of different sizes depending on the implant region, in order to obtain asymmetrical deployment and better therapeutic results. Moreover, the present invention makes it possible to control the shape of the implant once deployed in pre- The distance between the folds is also considered. Indeed, the distance between the synformal / antiformal folds, and therefore the distance between the long and short folds, determines how the sheet unfolds. Advantageously, if the density is higher at a certain point on the periphery, the unfolding will be greater, and if it is lower, the sheet will unfold less. It is understood that this results in asymmetry and curvature through a more extensive unfolding in the areas with the most folds. Similarly, it is possible to use more material (a large surface area of ​​the sheet on one side, for example) so that the lateral expansion is greater on that side than on the other. Furthermore, in some embodiments, the sheet is welded to the platens and therefore cannot unfold beyond the distance between the platens, which is set by the lifting mechanism.This results in an implant whose expansion is limited in one dimension (generally the essential dimension, where a precise height or width is desired), but not in another dimension. Therefore, the cement injection will expand the shell into any low-density bone volumes that may be present around the implant. It should also be noted that the fluid injection instrument (FEI) can be equipped with means to control the injected pressure (a manometer, for example) and to determine the resulting volume, in order to effectively control expansion within the bone tissue.Finally, it is understood that the instrumentation proposed in this application, in certain embodiments, using a relatively conventional implant holder (or ancillary device) to hold the implant and insert it into the bone tissue, but also a less conventional one for expanding it within the bone tissue, also offers the advantage of being able to perform all the implantation and stabilization steps with a single instrument in a continuous operation. Indeed, the ancillary device, with a hollow tube for delivering the cement through the tube that retains the cement, provides an instrument that allows the surgical operation to be performed quickly and efficiently. After drilling, the implant is inserted, and without removing the instrument, the shell can be expanded with cement and then the tool removed before, during, or even after the cement has polymerized (for example, using a mechanism that cuts the hardened cement during a rotation of the instrument).The time of the surgical operation is of course significantly reduced, but also the stability of the implant, which is not released at any point until it is stabilized by the injection of cement filling all the free volumes around it, unlike some solutions of the previous art.

[0039] The terms "cylinder," "cylindrical," or "generalized cylinder" are used interchangeably in this application for ease of disclosure of the invention and all refer to a "generalized cylinder," that is, a three-dimensional shape defined by a height (parallel to the longitudinal axis) and two bases (transverse to the longitudinal axis). These bases can have any shape, although a circular shape is preferred to simplify manufacturing and limit the risk of damage to the tissues into which the implant is inserted. Preferably, this "cylinder" is straight, meaning that its bases are aligned along the generatrix (or height) of the cylinder. Furthermore, since the implant can expand within a tissue, conforming to the shape of the space into which it is inserted (by modifying it through the pressure it exerts on these spaces), the shape may not be constant, and the two bases of the cylinder may have different shapes (surfaces).

[0040] 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.

[0041] 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.

[0042] In general, the present application relates to an expandable bone implant (1) for human orthopedic surgery for restoring the volume and / or geometry of a bone, by expansion between a folded configuration and a deployed configuration, said implant extending along a longitudinal axis (L) between a proximal end (11) connectable to an implantation instrument (A) for holding the implant and a distal end (12) intended to be inserted first into the bone, at least two faces of the implant, for example upper and lower, each comprising a tray (13, 14) for contact with bone tissue, each of the trays comprising a central portion (130, 140) connected, via at least one hinge, to at least one pair of support arms (131, 141) each oriented in opposite directions within each pair,one arm of each pair being connected by a hinge to the distal end (11) while the other arm is connected by a hinge to the proximal end (12), the implant (1) or having a central axis (3) or a housing suitable for receiving such an axis extending through a sliding sleeve at the proximal end (11) to a traction ring or sleeve at the distal end (12) where the axis is configured to transmit a traction, when actuation by an instrument (A), on the distal end (12) to enable it to be brought closer to the proximal end (11), causing the pivoting of the support arms (131, 141) causing the trays (13, 14) to move away from each other and, consequently, the expansion of the implant between the folded and deployed configurations. This proximal end can be connected to a grasping instrument (called an implant holder) and is therefore capable of cooperating with it.by means of attachment or physical connection, for example, known to a person skilled in the art. Nevertheless, some embodiments provide specific and advantageous attachment means to facilitate the grasping of the implant by an implant holder and, above all, the release of the implant by an L-shaped movement of the implant holder. On the other hand, by being connectable to the instrument, the implant is generally actuated for its expansion (in particular by the injection of a fluid inside and / or by pushing or pulling on an element of the implant), as widely known in the prior art. Indeed, many systems include expandable implants that can be actuated when mounted on a, An implant carrier that includes an actuation means for implant expansion (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 involves a pushing and / or pulling force). A person skilled in the art will therefore understand from reading this application that the implant can be defined without further detail regarding the instrument and the actuation, since these are standard mechanisms in the field. The system comprising the implant and the instrument is, of course, fully defined, but the implant alone is also clearly defined in its ability to be actuation independently of the instrument and without unnecessary detail about 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. Such an implant (1) is preferably characterized in that: - at least two other faces of the implant, between those containing the platforms, are covered with at least one sheet (10) per face, made of a biocompatible metal alloy, and hermetically bonded to the central portions (130, 140) under the platforms, to the lateral faces of the arms (131, 141) and to the lateral faces of the proximal end (11) and the distal end (12), - said sheet (10) is plastically deformable to allow expansion of the implant and has, at least in the folded configuration, a plurality of antiform folds (101), said convex, and synform folds (102), said concave, said folds being laid one on top of the other in the folded configuration, the total surface of said sheet being greater than or equal to the lateral surface of the implant in the deployed configuration so as to form a sealed compartment suitable for receiving a fluid inside the cavity obtained by the expansion of the implant

[0043] In some embodiments, the distance between a synform fold and the next antiform fold is longer than the distance between an antiform fold and the next synform fold, to facilitate folding said sheet onto the surface of the lateral faces of the implant in folded configuration.

[0044] In certain embodiments, the leaf on each lateral face of the implant, in the deployed position, has a substantially rhombus shape, with at least some of the folded creases remaining permanently near the proximal (11) and distal (12) ends. Generally speaking, it is understood that the implant will retain, even in deployed configuration, at least some of the sheet folds near the proximal and distal ends, but the dimensions and strength properties of the sheet (10) used allow the implant to be obtained and these persistent folds do not interfere with function and do not cause mechanical or physiological problems in bone tissues.

[0045] In some embodiments, said sheet is plastically deformable also from the folded configuration to the deployed configuration, in particular thanks to the persistence of the horizontal folds at the proximal and distal ends, facilitating the reversibility of the expansion.

[0046] In certain embodiments, said central axis (3) is connectable to an instrument and / or extends beyond the distal end of an implantation instrument (A) at the level of the proximal end of the implant, said instrument having an internal conduit in communication with a conduit (31) provided inside said central axis (3) and opening into the space provided by the spacing of the platforms, by at least one opening (32) allowing the injection of said fluid into the implant (1).

[0047] In some embodiments, attached to a lateral face of the proximal end (11), with the proximal end of the flat and folded pleats welded against the outer wall of said sleeve and / or joined to a face of the distal end (12) with the distal end of the flat and folded pleats welded against the outer wall of said sleeve by a weld (120).

[0048] In some embodiments, the folds are, at least in the folded configuration, parallel to the longitudinal axis (L).

[0049] In some embodiments, the number of folds ranges from 4 to 16, generally 6 to 12, preferably around 8. However, 3 folds may sometimes suffice, but the greater the number of folds, the less material deformation will occur, the lower the risk of tearing, and the easier the deployment. Thus, it is possible to use up to 20 folds.

[0050] In some embodiments, the sheet (10) has a thickness between 3 and 100 microns, generally between 6 and 50 and preferably between 10 and 30 microns.

[0051] In some embodiments, the sheet (10) is made of titanium alloy.

[0052] In some embodiments, the distance between the folds varies from one lateral face to the other of the implant, so that the shape of the implant in deployed configuration is asymmetrical transversely to the longitudinal axis (L).

[0053] In some embodiments, at least some of the support arms are provided in duplicate. Indeed, particularly to limit the risks of uneven expansion of the platforms, due to the opposing forces of the support arms and the external stresses exerted on the implant, it is preferable to provide support arms in duplicate, for example as shown in Figures 6A, 6B, 8A and 8B.

[0054] In addition, such double arms may include a self-locking mechanism in the deployed configuration, such as notches arranged opposite each other so as to engage with each other, for example as shown in the enlarged box in Figure 6 A.

[0055] Furthermore, to further improve the reliability and symmetry of the expansion, it is possible to provide support arms that are offset towards the ends of the platforms instead of just simple support arms articulated at the center of the platforms, for example as shown in figure 5C. Such a configuration makes it possible to create deformable parallelograms that retain their parallelism property between their sides, which makes expansion more reliable.

[0056] Regarding actuation and locking, it should be noted that the very small diameters of the implants and their central axes are difficult to adapt to threads for screw-type expansion at the implant level. It is advantageous, however, to screw the instrument actuating the expansion, particularly when the expansion involves bringing the support arms closer together. Thus, as known in the prior art, it is possible to use, for example, a split ring housed in a circular reinforcement of the implant and cooperating with notches on the thrust or traction axis. These notches are oriented to allow the axis to pass in only one direction, as shown in Figures 10A, 10, and 10C. In this way, the axis for expanding the platforms can be actuation by successively engaging the notches, forming a notched lock (VC) to secure the implant in the deployed configuration.

[0057] This application also relates to an orthopedic treatment system for damaged bone tissue comprising an implant, a bone replacement cement and at least one instrument (A) for implanting and injecting cement into said implant, said system being characterized in that said implant is an implant according to one of the embodiments described herein.

[0058] In some embodiments, the implantation and cement injection instrument includes means for controlling the pressure and / or suction of the cement to fold the implant into a folded configuration if necessary.

[0059] In some embodiments, the implantation instrument is separate but complementary to the injection instrument, the cement injection channel of which passes through a channel inside a hollow stem of the implantation instrument configured to hold the proximal end of the implant at the distal end of said hollow stem.

[0060] 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 the injection site (by compressing the cancellous bone tissue) and allow, for example, the fluid to be injected in two stages for better adjustment of the shape, the resulting temperature in the tissues, and / or the polymerization rate of the fluid.

[0061] This application also relates to a method for manufacturing an implant according to one of the preceding claims, said method being characterized in that it comprises: a) Obtaining an expandable implant with two trays that separate under the effect of bringing the ends of the implant together by means of support arms connecting these ends to the trays; b) Insertion of a sheet of biocompatible metallic material between two racks equipped with triangular profile grooves to imprint folds on the sheet; c) Folding the folds one on top of the other, to obtain a folded sheet; d) Placement of said folded sheet on one lateral face of the implant; e) Securing said sheet on said lateral face; f) Reiteration of steps b) to e) for the other face of the implant.

[0062] 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).

[0063] 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.

[0064] 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.

[0065] Figure 1A shows a perspective view of an expandable implant in its folded configuration, according to certain embodiments, and Figure 1B shows a perspective view of the same implant in its deployed configuration. In Figure 1B, it can be seen that the sheet (10) is welded to the arms 131-141 between the platforms, and the latter are therefore free to move apart, allowing the sheet to conform to the shape of the implant during its deployment.

[0066] Figure 2A shows a perspective view of an expandable implant from which the foil has been removed, showing the weld line of the foil, while Figure 2B shows the same implant with the foil present, and the weld line is shown as a dashed line. Figure 2A illustrates the path of the foil weld on the implant body, particularly on the central reinforcements and the implant arms, and Figure 2B also shows that the foil can extend beyond the weld because it is flexible and no further adjustments are necessary.

[0067] Figure 3A shows a transparent view of an expandable implant according to certain embodiments, with section planes BB and CC of Figures 3B and 3C respectively showing sectional views along section planes BB and CC of Figure A, and each an enlargement showing the weld line of the sheet on the implant in these cross-sectional planes, according to certain embodiments. These figures thus allow us to see that at the ends of the implant, the weld is continuous over one face of the implant while at the level of the deployable part of the implant, the weld is made, at the center of the implant along the longitudinal axis, only on the central reinforcements (130, 140) and, between this center and the proximal and distal ends, only on the support / deployment arms (131, 141) to allow the spreading of the trays and the unfolding of the sheet (10) welded on these reinforcements (130, 140) and arms (131, 141).

[0068] Figure 4A shows a perspective view of an expandable implant in its folded configuration and without its foil, according to certain embodiments. Figure 4B shows the same implant as in Figure 4A but in its deployed configuration, and Figure 4C shows an expandable implant with a foil on only one of its faces. Figures 4A and 4B represent embodiments similar to the prior art where the implant does not have a foil to limit cement leakage, but Figure 4C shows such an implant with only one face covered by the foil to demonstrate the advantage of being able to retain a specific volume of cement. This specific volume can vary from one face of the implant to the other depending on the number of folds made.

[0069] Figure 5A shows a side view of a pre-folding rack for expandable implants according to certain embodiments, and Figure 5B shows a side view of a pre-folding rack according to other embodiments. Figure 5C shows a side view of a double-arm expandable implant according to certain embodiments. Thus, Figures 5A and 5B represent two different embodiments for obtaining short and long folds, allowing the folds to overlap on each face of the implant while preserving the overall shape of the implant (whereas identical symmetrical folds would cause the sheet folds to overlap in the folded configuration, generating excess material on the lateral faces of the implant).In the variant shown in Figure 5A, the long and short folds are made symmetrically on either side of the median (vertical) axis of the implant, whereas in Figure 5B, the distribution of long and short folds is continuous in the same direction across the entire face of the sheet. This results in folds all oriented in the same direction on each face of the implant onto which such a sheet will be welded. Figures 5A and 5B represent folding tools in the form of racks defining a mean plane for flattening the sheet (10) and creating folds in this mean plane. However, it is possible to provide, as an alternative (or in addition), at least one toothed roller cooperating with a toothed rack or another toothed roller to produce the same type of folds as the flat racks in Figures 5A and 5B.

[0070] Furthermore, Figure 5c depicts an alternative embodiment in which the number of deployment arms has been doubled by adding extra arms near the ends of the trays. This type of configuration offers improved stability and reliability during deployment because the presence of pairs of arms on each side of the implant relative to its center, along the longitudinal axis, provides a configuration comprising deformable parallelograms that limit the risk of non-parallel tray separation, whereas with single arms, there is generally a risk of unintended deployment of the trays, not parallel to each other due to the resistance forces that the trays encounter against the surrounding tissues during the expansion of the implant.

[0071] Figure 6A shows a cross-sectional view of an expandable implant supported by an implantation instrument, with an enlargement showing details of the double support arms with a self-locking mechanism. Figure 6B shows a cross-sectional view of a vertebra into which an expandable implant is implanted according to other embodiments. Figure 6A shows a partially cross-sectional profile view of a prior art implant in which the deployment arms have self-locking structures that lock the implant in the deployed position through the interlocking of notches when the implant is fully deployed. This type of structure, known from the prior art, can naturally also be used in the present invention.Figure 6B depicts a variant of the prior art in which the implant has only one platform, thus allowing deployment in a single direction perpendicular to the longitudinal axis, which can be useful in certain cases. The present design naturally also allows for this type of embodiment.

[0072] Figure 7A represents a top view of a vertebra in which an implant is implanted according to various embodiments, Figure 7B represents a perspective view of a vertebra in which an anterior art implant is implanted and Figure 7C represents a perspective view of a vertebra in which an implant is implanted according to certain embodiments.

[0073] Figure 8A shows a perspective view of an implant according to certain embodiments, and Figure 8B shows a perspective view of an implant according to other embodiments. Figure 8A shows an alternative embodiment in which the platforms have a particular shape to conform to the shape of the bone structures to be treated with the implant, such as vertebral spines, to form an interspinous implant. The present invention also allows for this type of platform shape, as well as any other shape, for the geometric restoration of various bone structures of various shapes, whether vertebral or not.Figure 8B depicts another prior art embodiment in which the deployment arms (131, 141), at least on one end of the implant, are supported by a second pair of arms (131b, 141b). This provides greater stability by creating a deformable parallelogram, thus improving the reliability of the platform deployment. However, this embodiment may prove less efficient than that of Figure 5C detailed above, which features more effective parallelograms spaced further apart proportionally to the implant size.

[0074] Figures 9A, 9B, and 9C show profile views of vertebrae with vertebral compression fractures (VCF), respectively at the anterior, midline, and posterior levels. 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 the angle of insertion of the implant, depending on the type of surgical approach used (e.g. lateral, anterior, dorsal, transforaminal, transpedicular, etc.)

[0075] Figure 10A shows a perspective view of an implant without its leaf according to certain embodiments, and Figure 10B shows the same implant with the expansion rod removed. Figure 10C shows a cross-sectional view of the implant of Figure 10A with the expansion rod present. Figure 10A illustrates an embodiment in which deployment is achieved by a mechanism known from the previous discussion. As shown in Figure 10B, this mechanism includes a notched lock (VC) with a circumferential groove for receiving a split ring that serves 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 10C, pulling 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.

[0076] 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.

[0077] Detailed list of references in the figures: I implant 10 sheets, 101 folds II proximal end LS weld line 12 distal end A CPI implantation instrument, first pre-bending rack, CP2 second pre-bending rack, CP3 third pre-bending rack, CP4 fourth pre-bending rack, 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 130 central portion of the first plateau 140 central portion of the second plateau 131 support arms for the first tray 141 support arms for the second platform 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 extended configuration, said implant extending along a longitudinal axis (L) between a proximal end (11) connectable to an implantation instrument (A) for holding the implant and a distal end (12) intended to be inserted first into the bone, at least two faces of the implant, for example superior and inferior, each comprising a platform (13, 14) for contact with bone tissue, each of the platforms comprising a central portion (130, 140) connected, via at least one hinge, to at least one pair of support arms (131, 141) each oriented in opposite directions within each pair, one arm of each pair being connected by a hinge to the distal end (11) while the other arm is connected by a hinge to the proximal end (12),the implant (1) comprising a central axis (3) or a housing adapted to receive such an axis extending through a sliding sleeve at the proximal end (11) to a traction ring or sleeve at the distal end (12) where the axis is configured to transmit a traction, when actuation by said instrument (A), on the distal end (12) to allow it to be brought closer to the proximal end (11), causing the pivoting of the support arms (131, 141) resulting in the separation of the platforms (13, 14) from each other and, consequently, the expansion of the implant between the folded and deployed configurations, the implant being characterized in that:, - at least two other faces of the implant, between those containing the platforms, are covered with at least one sheet (10) per face, made of a biocompatible metal alloy, and hermetically bonded to the central portions (130, 140) under the platforms, to the lateral faces of the arms (131, 141) and to the lateral faces of the proximal end (11) and the distal end (12), - said sheet (10) is plastically deformable to allow expansion of the implant and has, at least in the folded configuration, a plurality of antiform folds (101), said convex, and synform folds (102), said concave, said folds being laid one on top of the other in the folded configuration, the total surface of said sheet being greater than or equal to the lateral surface of the implant in the deployed configuration so as to form a sealed compartment suitable for receiving a fluid inside the cavity obtained by the expansion of the implant.

2. Implant according to claim 1, characterized in that the distance between a synformal fold and the next antiformal fold is longer than the distance between an antiformal fold and the next synformal fold, to facilitate the folding of said sheet onto the surface of the lateral faces of the implant in folded configuration.

3. An implant according to any one of the preceding claims, characterized in that said sheet on each lateral face of the implant has, in the deployed position, a substantially [shaped] diamond, with a permanent persistence of at least part of the folded folds near the proximal (11) and distal (12) ends.

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

5. 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, said instrument having an internal conduit in communication with a conduit (31) formed inside said central axis (3) and opening into the space formed by the spacing of the plates, by at least one opening (32) allowing the injection of said fluid into the implant (1).

6. Implant according to any one of the preceding claims, characterized in that said sheet (10) is attached to a lateral face of the proximal end (11), with the proximal end of the horizontal and folded folds which is welded against the outer wall of said sleeve by a weld (110) and / or attached to a face of the distal end (12) with the distal end of the horizontal and folded folds which is welded against the outer wall of said sleeve by a weld (120).

7. 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).

8. Implant according to any one of the preceding claims, characterized in that the number of folds is between 4 and 16, generally 6 to 12, preferably in the order of 8.

9. 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.

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

11. 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 asymmetric transversely to the longitudinal axis (L).

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

13. System according to claim 12, 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.

14. System according to any one of claims 12 and 13, characterized in that the implantation instrument is different from but complementary to the injection instrument, the cement injection channel of which passes through a channel inside a hollow stem of the implantation instrument configured to hold the proximal end of the implant at the distal end of said hollow stem.

15. A method for manufacturing an implant according to any one of the preceding claims, said method being characterized in that it comprises: a) Obtaining an expandable implant with two trays that separate under the effect of bringing the ends of the implant together by means of support arms connecting these ends to the trays; b) Inserting a sheet of biocompatible metallic material between two racks having triangular profile grooves to imprint folds in the sheet; c) Folding the folds one on top of the other, to obtain a folded sheet; d) Arranging said folded sheet on one lateral face of the implant; e) Securing said sheet to said lateral face; f) Repeating steps b) to e) for the other face of the implant.

Images