Osseous anchoring implant with optimized expansion

Abstract

The present invention relates to a bone anchoring implant with optimised expansion, comprising a tubular body (2) and a rod (1), the outer profiles of the rod (1) and the inside of the tubular body (2) of which are complementary, the implant being expandable between a rest configuration, wherein a stop mechanism reciprocally locks the tubular body (2) and the rod (1) due to the reversal of their two respective screw pitches, such that they provide in a radially expandable configuration: a proximal fulcrum, a distal fulcrum, a "central" fulcrum located between said two fulcrums, formed by the cooperation between the outer diameter of the rod (1) and the inner diameter of the tubular body (2) which induce an outer diameter of the tubular body (2) at the central fulcrum greater than the outer diameter of the tubular body (2) at the proximal fulcrum.

Description

[0001] Description

[0002] OPTIMIZED EXPANSION BONE ANCHOR IMPLANT TECHNICAL FIELD AND OBJECT OF THE INVENTION

[0003] The present invention relates to the field of bone implants for dental, orthopedic, surgical, or osteoplastic applications, such as orthopedic screws alone or with plates, dental or ligament implants for joints such as, for example, the hips, elbows, ankles, shoulders, and knees, or spinal implants, for example, for vertebrae. These fields of application are given by way of example and are not restrictive as to the scope of the present invention.

[0004] More specifically the invention relates to a bone implant whose implantation in bone tissue is stabilized by an expansion particularly in the spongy part of the bone.

[0005] STATE OF THE ART

[0006] A bone anchoring implant is generally made up of an elongated body designed to be implanted into a socket formed in bone tissue, such as the jawbone for a dental application or in a vertebra, for example.

[0007] It is important that the bone anchoring implant can be easily inserted into the bone tissue without causing damage, and that the anchoring device within the bone tissue is stable. Indeed, current bone implant devices do not allow for reliable anchoring without causing cracks or damage to the bone tissue that exceeds the size of the device itself. Reliable and stable fixation of the bone anchoring implant is essential because many current treatment techniques rely on bone growth, which generally requires that the devices anchored in the bone tissue remain as immobile as possible.

[0008] Furthermore, it is also necessary that implantation in the bone tissue be easy to perform in order to avoid any risk of malpositioning of the bone anchoring implant, which could be due to difficulties in positioning or implantation within the bone. The prior art includes patent document EP2603163 Bl, which describes an improved anchoring endo-osseous implant suitable for implantation in bone tissue and comprising a fixation device including a so-called anchoring portion in the bone tissue and an expansion portion, these two portions being movable relative to each other.The invention described in this patent also includes cooperating mechanical linkage means arranged, on the one hand, on the anchoring portion and, on the other hand, on the expansion portion, such that the relative mobility of the two portions includes at least one degree of freedom and that a relative displacement of said two portions causes an expansion of the anchoring portion, said expansion causing the anchoring of the anchoring portion in the bone tissue. The bone implant described in this patent finds particular application in the dental field.

[0009] However, this solution has drawbacks because the proposed bone implant has a conical section only on its distal portion, which opens into slits. The expansion of the bone implant within the bone tissue then occurs radially and homothetically, making it less stable, particularly during its removal from the bone tissue. This removal initially causes the bone implant to retract before it can be completely extracted.

[0010] The invention therefore aims to resolve these drawbacks by proposing a bone implant suitable for being implanted and immobilized in bone tissue in a stable manner.

[0011] GENERAL PRESENTATION OF THE INVENTION

[0012] The present invention therefore aims to overcome the disadvantages of the prior art by proposing a bone anchoring implant, hereinafter referred to as a bone implant, which is easily implantable in bone tissue, stable, and also easily removed from bone tissue.

[0013] To achieve this result, the present invention relates to an optimized expansion bone anchoring implant, comprising:

[0014] A tubular body extending between a proximal portion having a first internal diameter, and a distal portion having a second internal diameter smaller than said first internal diameter, these two portions defining a longitudinal axis (L) and said first and second internal diameters defining an internal profile of said tubular body, and comprising, on the one hand, at least one first thread inside the tubular body and, on the other hand, at least one second thread outside the tubular body,

[0015] A rod extending between a proximal portion and a distal portion on an axis collinear with the axis (L) and having, on the one hand, along said longitudinal axis (L), an external profile complementary to said internal profile of said tubular body and, on the other hand, at least one external thread whose thread pitch is reversed with respect to said second external thread of the tubular body,

[0016] The implant being expandable between, on the one hand, a resting configuration in which a stop mechanism reciprocally locks said tubular body and said stem by reversing these two screw threads, and, on the other hand, an expanded configuration obtained by the actuation of said complementary internal and external threads of the tubular body and stem reciprocally, causing the stem to penetrate the tubular body and generating the expansion of said tubular body, thanks to the external diameter of the stem which is greater than the internal diameter of the tubular body, at least on a distal portion, by deformation of the tubular body during the penetration of the stem into the tubular body,

[0017] The outer profiles of the stem and the inner profiles of the tubular body being complementary, they provide, in their expanded configuration:

[0018] A proximal support point is achieved through the complementarity of the external diameter of the stem with the internal diameter of the tubular body.

[0019] A distal support point is achieved through cooperation between the tubular body, whose internal diameter narrows towards the distal portion until it is smaller than the external diameter of the stem.

[0020] A "central" support point located between these two support points (at the proximal and distal level), formed by the cooperation between the external diameter of the rod and the internal diameter of the tubular body which induce, in expanded configuration, an external diameter of the tubular body at the "central" level which is greater than the external diameter of the tubular body at the level of the proximal support point.

[0021] According to one particular feature, the external diameter of the tubular body at the "central" level is greater than the external diameter of the tubular body at the distal support point. According to another particular feature, the distal support point is formed on at least a portion of the distal portion complementary to the external profile of the stem. According to yet another particular feature, the distal support point is formed by the distal portion comprising a tip whose external profile is complementary to the internal profile of the distal portion of the tubular body.

[0022] According to another peculiarity, the central support point is formed by at least one rib protruding inside the tubular body, on an intermediate portion between the distal and proximal portions, so that said rib cooperates, during expansion, with the outer surface of the stem between its proximal and distal portions.

[0023] According to another feature, the reciprocal stop mechanism includes a rib or shoulder or projection inside the tubular body complementary to the outside diameter of the rod, or a rib on the inside of the tubular body, complementary to a groove or shoulder on the rod.

[0024] According to one particular feature, the reciprocal stop mechanism includes a rib protruding inside the tubular body, complementary to a shoulder or notch located on the tip of the rod.

[0025] According to another peculiarity, the central support point and the stop mechanism mutually locking the tubular body and the rod are formed by the same elements cooperating, respectively, in expanded configuration or in rest configuration.

[0026] According to another feature, the outer diameter of the stem is greater than the inner diameter of the tubular body by at least one constriction on a distal portion. According to another feature, said at least one constriction is located, relative to the proximal portion and along the longitudinal axis (L), at a distance determined according to the depth, within the bone tissue at which said expansion is desired.

[0027] According to another peculiarity, the tubular body includes on its distal portion a frustoconical portion whose inner diameter is less than the outer diameter of the stem.

[0028] According to another distinctive feature, the truncated conical portion has a thread with a conical core allowing the tubular body to penetrate deeply into the bone.

[0029] Another distinctive feature is that the distal portion has self-tapping notches. Another distinctive feature is that the distal portion has longitudinal opening slots allowing for the expansion of the tubular body.

[0030] Another distinctive feature is that there are as many self-tapping notches as there are through longitudinal slots.

[0031] According to another peculiarity, the distal portion has non-opening longitudinal slits allowing expansion of the tubular body.

[0032] According to another feature, the stem includes at least one distance marker to visualize when the screwing of the screw into the tubular body should be carried out in the opposite direction to the screwing of the tubular body into the bone tissue.

[0033] PRESENTATION OF THE FIGURES

[0034] Other features and advantages of the invention will become apparent upon reading the detailed description of embodiments of the invention, given by way of example only, and with reference to the drawings which show:

[0035] [Fig. 1a], [Fig. 1b] and [Fig. 2] represent a detailed view of the elements that make up the bone implant according to the invention.

[0036] [Fig. 3a] represents a detailed view of the tubular body before expansion according to the invention.

[0037] [Fig. 3b] and [Fig. 3c] represent a detailed view of the tubular body after expansion according to the invention.

[0038] Figures 4a and 4b illustrate a schematic cross-section of the interior of the stem entering the tubular body at the reciprocal stop, according to the invention. Figures 5a and 5b illustrate a schematic view of the interior of the bone implant in the expanded position according to the invention.

[0039] [Fig. 6] and [Fig. 7] represent an external view of the bone implant in the expanded position according to the invention.

[0040] [Fig. 8] and [Fig. 9] show a view of the expanded tubular body according to the invention. [Fig. 10] shows a schematic cross-section of the interior of the tubular body including the rod, in the expanded position, according to the invention.

[0041] DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION Various embodiments of the invention are described below, in particular with reference to the illustrative and non-limiting figures.

[0042] This application concerns the implantation of a bone implant in bone tissue.

[0043] It should be noted here that the term "implantation" refers to the process of inserting the bone implant into the bone tissue, generally by screwing. The implantation proposed in this application refers to an insertion of the bone implant that is sufficiently strong and stable to ensure its proper retention within the bone tissue.

[0044] Furthermore, the term "bone tissue(s)" generally refers to all types of bone, whether compact bone (such as cortical bone or periosteum) or spongy bone (soft, porous), because the bone implant system of this application is implantable in any type of bone tissue.

[0045] Furthermore, the terms used should not be interpreted in their general sense but rather in light of the functional considerations detailed in this application.

[0046] [Fig. 1a], [Fig. 1b] and [Fig. 2] are illustrative and non-limiting examples of the realization of the bone implant.

[0047] As for example shown in [Fig. 1a], [Fig. 1b] and [Fig. 2], a bone implant comprises: a tubular body (2) extending along a longitudinal axis (L) between a proximal portion (22) and a distal portion (23) which includes, on the one hand, at least a first thread (20) inside the tubular body (2) and, on the other hand, at least a second thread (21) outside the tubular body (2).

[0048] In this application, the term tubular body (2) generally refers to a hollow generalized cylinder.

[0049] In some embodiments, the bone implant also includes a stem (1) extending also along said longitudinal axis (L) between a proximal portion (12) and a distal portion (13) and having, on the one hand, along said longitudinal axis (L), an external profile complementary to the internal profile of said tubular body (2) and, on the other hand, at least one external thread (11) whose screw pitch is reversed with respect to said second external thread (21) of the tubular body (2).

[0050] The terms "proximal" and "distal" in this application refer, respectively, to the part where the implant device is held to allow its implantation into the bone tissue, and the part that is implanted first into the bone tissue (as opposed to the proximal portion).

[0051] The terms proximal and distal "portions" in this application refer to the parts located near the distal and proximal ends.

[0052] In some embodiments, the proximal portion (12) of the stem (1) is directly implanted into the cortical bone.

[0053] In some embodiments, the proximal end of the rod (1) includes an actuating means for screwing the rod (1), said actuating means comprising a structure of any shape desirable to the practitioner depending on its intended use, as shown for example in [Fig. 1a]. The actuating means being, for example, a hex hole or a Torx or a Phillips head or any other actuating means, and the proximal end of the rod (1) may have various shapes depending on the desired destination for the bone anchoring implant (fixation head for a polyaxial or non-polyaxial osteosynthesis bar, or fixation for a plate or any other device).

[0054] In some embodiments, the stem (1) includes a cannula passing through the stem (1) to allow the practitioner to inject, for example, cement, if he deems it necessary.

[0055] In certain embodiments, the second thread (21) on the outside of the tubular body (2) allows for bone anchoring. The term "bone anchor" used in this application generally refers to various types of devices comprising at least one element designed to penetrate bone tissue along a straight path, under the action of a thrust generally exerted in the form of repeated blows, impacts, or screwing. It is known that a bone anchor thread generally has a greater thread height than a mechanical thread to ensure better anchoring. Furthermore, a bone anchor thread is generally different from a mechanical thread, and those skilled in the art know that, depending on the type of bone and the desired application, it is possible to vary the core diameter, the thread pitch, and the thread height, and this application covers these various embodiments.

[0056] Furthermore, in certain embodiments, some mechanical threads, such as trapezoidal threads, offer less resistance, which facilitates the penetration of the stem into the tubular body anchored in the bone. Indeed, a trapezoidal thread allows for the distribution of a significant load in compression and tension, thus improving the implant's stability over time and under all conditions. In some embodiments, the tubular body (2) includes, on its distal portion (23), a frustoconical portion (291) whose inner diameter is smaller than the outer diameter of the stem (1).

[0057] In some embodiments, the frustoconical portion (291) has a thread (232) with a conical core allowing the tubular body (2) to penetrate deeply into the bone.

[0058] In some embodiments, the distal portion (23) of the tubular body (2) is self-tapping and has self-tapping notches (231) (milling and tapping), as shown for example in [Fig. 3a], [Fig. 3b], [Fig. 4a], and [Fig. 4b]. This distal portion (23) helps preserve bone during implantation by avoiding pre-drilling before implant insertion, thus preserving a maximum amount of bone around the implanted area and improving the stability of the bone implant. Indeed, the osseointegration time is thus reduced, limiting the need to add any type of bone graft material, whether synthetic or natural. Furthermore, the distribution of the notches (231) ensures a good balance on each part of the distal portion (23) and thus a good homogeneity of the distribution of the effort during the insertion of the implant into the bone tissue.

[0059] In some embodiments, the stem (1) includes at least one distance marker (16) to visualize when the screwing of the stem (1) into the tubular body (2) should be carried out in the opposite direction to the screwing of the tubular body (2) into the bone tissue.

[0060] In some embodiments, the distance marker (16) is a laser marking used as a positioning reference for the practitioner when the bone implant is inserted into the bone, as shown for example in [Fig. 2].

[0061] It should be noted that the bone implant is made of titanium or implantable medical stainless steel or polyetherketoneketone (PEKK) or polyetheretherketone (PEEK) or any other material whose suitability can be determined by a person skilled in the art based on its mechanical, physico-chemical properties and biocompatibility.

[0062] This application also relates to a method for implanting an implant as described in the various embodiments of this application. In some embodiments, such a method comprises the following steps:

[0063] The bone implant is screwed in along the external thread (21) until the distance marker (16) is flush with the surface of the cortical bone,

[0064] The screwing of the bone implant by screwing in the direction of the second thread (11) to complete the screwing of the body of the threaded rod (1) into the bone and proceed to the expansion of the tubular body (2).

[0065] In some embodiments of the procedure, the process includes creating an opening to allow the insertion of the implant through the cortical bone using a cortical preform tool. This is particularly the case when the material used to fabricate the implant is PEEK.

[0066] In other embodiments, this perforation is not necessary thanks to the self-tapping notches (231).

[0067] This application also relates to the expansion of a bone implant into bone tissue.

[0068] In some embodiments, such as shown in [Fig. 3a], the tubular body (2) has an acute angle α at the end of its distal portion (23). This angle α opens and increases as the rod (1) penetrates the tubular body (2) during expansion.

[0069] In some embodiments, such as shown for example in [Fig. 3b], angle a, opening more and more during expansion, becomes an angle b, angle b being the angle of the expanded tubular body (2).

[0070] It should be noted that in the deployed position, the walls of the tubular body (2) can in some embodiments be parallel instead of creating an angle b.

[0071] In some embodiments, the tubular body (2) has a convex shape at the central support point, as shown for example in [Fig. 3c], by the presence of angles a and b. In these embodiments, the implant therefore has, in expanded configuration, an external diameter at the central support point which is greater than the external diameters of the implant at the distal and proximal portions, as detailed below.

[0072] In certain embodiments, such as for example shown in [Fig. 5a], [Fig. 5b] and [Fig. 10], the implant is expandable between, on the one hand, a rest configuration in which a stop mechanism reciprocally locks the tubular body (2) and said rod (1) by reversing their two respective threads, and, on the other hand, an expanded configuration obtained by the actuation of said complementary internal and external threads of the tubular body (2) and the rod (1) reciprocally, causing the penetration of the rod (1) into the tubular body (2) and generating the expansion of said tubular body (2), thanks to the external diameter of the rod (1) which is greater than the internal diameter of the tubular body (2), at least on a distal portion, by deformation of the tubular body (2) during the penetration of the rod (1) into the tubular body (2).

[0073] As shown for example in [Fig. 5a] to [Fig. 10], the outer profiles of the rod (1) and the inner profiles of the tubular body (2) are complementary, so that in certain embodiments they provide, in expanded configuration:

[0074] A proximal support point supported by the complementarity of the external diameter of the rod (1) with the internal diameter of the tubular body (2), this proximal support point does not cause deformation of the tubular body (2),

[0075] A distal support point supported by the cooperation between the tubular body (2) whose internal diameter narrows towards the distal portion until it is less than the external diameter of the stem (1),

[0076] A "central" support point located between the two support points, distal and proximal, formed by the cooperation between the external diameter of the rod (1) and the internal diameter of the tubular body (2) which induce, in expanded configuration, an external diameter of the tubular body (2) at the "central" level which is greater than the external diameter of the tubular body (2) at the level of the proximal support point, said central support point not necessarily being located exactly in the middle of the other two support points.

[0077] In some embodiments, the distal support point is formed by the distal portion (13) of the stem comprising a tip (17), the external profile of which is complementary to the internal profile of the distal portion (23) of the tubular body (2). In some embodiments, the distal portion (13) is stopped in translation in the direction of the external thread (21) by the reciprocal stop configured in the tubular body (2), the shape of said reciprocal stop and the internal shape of the tubular body (2) being configured to cause radial expansion of the tubular body (2) when the stem (1) is screwed into the tubular body (2).In some embodiments, the expansion of the distal portion of the implant is ensured by the cooperation between the conical or frustoconical profile of the tip (17) of the stem (1) and the internal diameter of the tubular body (2), while the expansion of the central support point is ensured by the cooperation between the internal diameter at the level of the central support point of the tubular body (2) with respect to the increase in the external diameter of the stem (1), from the reciprocal stop towards the proximal portion.

[0078] Preferably, this increase in the outer diameter of the stem (1) is located at a predetermined distance from the distance marker (16), so it is possible to screw the implant in the rest position up to said distance marker (16) and then screw in the opposite direction to allow penetration of the stem inside the sleeve followed by expansion of the tubular body (2), while controlling the depth at which the expansion will take place.

[0079] Furthermore, the outer diameter of the stem (1) is greater than the inner diameter of the tubular body (2) by means of at least one constriction (271) on a distal portion (23), the outer diameter of the stem (1) reaching its maximum size at the distance along the longitudinal axis (L) corresponding to the central fulcrum in the expanded position. Said at least one constriction (271) is located, relative to the proximal portion and along the longitudinal axis (L), at a distance determined according to the depth, within the bone tissue at which said expansion is desired, as shown for example in [Fig. 4a] and [Fig. 4b].

[0080] Said narrowing (271) is located at a variable distance from the tip (17).

[0081] In some embodiments, the reciprocal stop mechanism includes a projection (26) (or projecting rib), referred to as a rib in a non-limiting manner, inside the tubular body (2), complementary to a shoulder or notch (172) located on the tip of the rod (1).

[0082] In some embodiments, the diameter of the stem (1) increases progressively from said shoulder or notch (172), towards the distal portion (13) of the stem (1) to allow the central support point to expand the tubular body (2).

[0083] In some embodiments, the proximal support point is formed on at least a portion of the distal portion (23) complementary to the external profile of the rod (1). This proximal support point corresponds to a complementarity of diameters between the tubular body (2) and the rod (1).

[0084] In some embodiments, the "central" support point is formed by at least one projection (26) (for example, a projecting rib) inside the tubular body (2), on an intermediate portion between the distal portion (23) and the proximal portion (22), so that said rib (26) cooperates, during expansion, with the outer surface of the stem (1) between its proximal and distal portions.

[0085] In certain embodiments, the external diameter of the tubular body (2) at the "central" level is also preferably greater than the external diameter of the tubular body (2) at the distal support point, resulting in the convex shape described above (of the tubular body (2) and the implant in general) at the central support point, for example as shown in [Fig. 3c] and [Fig. 10]. In these embodiments, the convex shape in the expanded configuration is achieved because the interaction between the distal ends of the stem (1) and the tubular body (2) results in an external diameter of the implant that is smaller than that imposed at the central support point detailed in this application.Furthermore, this expansion in a convex shape is facilitated in certain embodiments by the presence of non-through slots (25) on a central portion of the tubular body, as detailed in the present application (these non-through slots (25) also having the advantage of allowing bone tissue growth in the implant to improve the stability of the implant).

[0086] Furthermore, in some embodiments, a synergistic effect is observed between the reciprocal stop and the "central" support point, allowing screwing at the start but also support during expansion.

[0087] In certain embodiments, the central fulcrum and the stop mechanism that mutually locks the tubular body (2) and the stem (1) are formed by the same elements (or at least elements common to both mechanisms) cooperating, respectively, in the expanded or resting configuration. These same cooperating elements together form a single structure performing two different functions depending on the configuration. Indeed, these elements, which include the rib (26) and the external profile of the stem (with the notch (172) near its distal end), cooperate, on the one hand, in the resting configuration, so as to form the reciprocal stop (allowing screwing into the bone) and, on the other hand, in the expanded configuration, so as to create the central fulcrum (allowing expansion of the implant).By acting as a stop against the notch (172), the rib (26) holds the stem (1) relative to the tubular body (2) during screwing of the implant into the bone and during reverse screwing (of the stem (1) into the tubular body (2)). Thanks to the reverse thread pitch of the external thread (11) of the stem (1) relative to the second external thread (21) of the tubular body (2), as detailed above, the interaction of the rib (26) with the external profile of the stem (1) (which increases towards the proximal end) induces expansion of the tubular body (2). It is therefore clear that these two technical effects of screwing and central expansion are achieved by common elements exhibiting synergy, which provides various advantages for the implant (simplicity and cost of manufacture, stability, etc.).

[0088] In some embodiments, the reciprocating stop mechanism further includes a rib, shoulder, or projection inside the tubular body (2), complementary to the outer diameter of the stem (1), or a rib on the inside of the tubular body (2), complementary to a groove or shoulder on the stem (1). The support points at the point of maximum expansion limit the risk of collapse in the areas subjected to the greatest cumulative contact forces between the bone and the implant.

[0089] As shown for example in [Fig. 3a] to [Fig. 3c], and [Fig. 6] to [Fig. 10] the distal portion (23) of the tubular body (2) includes in particular open longitudinal slits (24) and non-opening slits (25) to allow cylindrical expansion of the tubular body (2).

[0090] In some embodiments, the synergy between the through slots (24) and the non-through slots (25) further enables a truncated cone geometry. In some embodiments, expansion is made possible by at least one through (24) or non-through (25) longitudinal slot, preferably several through (24) or non-through (25) slots. It is also preferable for the distal portion (23) to have both types of slots, i.e., through longitudinal slots (24) and non-through longitudinal slots (25). It should be noted that the distribution of the notches (231) in the self-tapping portion (23) of the tubular body (2) depends on the number of through (24) and non-through (25) longitudinal slots. The non-through longitudinal slots (25) and the central support point allow the expansion of the tubular body (2).In some embodiments, there are as many self-tapping notches (231) as through longitudinal slots (24).

[0091] As shown for example in [Fig. 5a] to [Fig. 10] the tubular body (2) is expanded after penetration of the rod (1) into the tubular body (2).

[0092] In some embodiments, the tubular body (2) expands cylindrically, and the open (24) and closed (25) longitudinal slots on the distal portion (23) of the tubular body (2) allow for cylindrical expansion of the tubular body (2) by permitting elastic or plastic deformation of the tubular body (2) during the penetration of the stem (1) into the tubular body (2). The tubular body (2) can be made, for example, of titanium, which has good plastic deformation properties. The closed longitudinal slots (25) thus contribute to the stability of the bone implant in the bone tissue by allowing the contact profile to be maintained at the three points of support between the tubular body (2) and the stem (1) during expansion, and by allowing the forces due to expansion to be distributed homogeneously around the periphery of the expanded tubular body (2).

[0093] In some embodiments, the through slots (24) and the non-through slots (25) are arranged in an offset arrangement relative to each other along the length; this offset arrangement improves the flexibility and mechanical resistance of the tubular body (2) during expansion.

[0094] Finally, in some embodiments, the non-opening slits (25) allow the tubular body (2) to expand in the spongy bone tissue by presenting a domed, convex shape, allowing the material to be compressed and densified on its periphery, thus improving primary stability, healing, and avoiding the addition of cement to stabilize and immobilize the bone implant.

[0095] The bone implant proposed in the invention can therefore be implanted quickly and precisely into bone tissue, and remain implanted very stably in bone tissue.

[0096] This application describes various technical features and advantages with reference to the figures and / or various embodiments. Those skilled in the art will understand that the technical features of a given embodiment can in fact be combined with features of one or more other embodiments unless the reverse is explicitly stated, or unless such features are incompatible, or the combination is ineffective. More generally, combinations of various types of implant retention means and / or spinous process retention means are envisaged and will be assessed by those skilled in the art using the functional and structural considerations provided in this application.Furthermore, the technical features described in a given embodiment can be isolated from the other features of that embodiment unless the opposite is explicitly stated, in particular because the functional considerations provided in this application will provide sufficient explanation for any structural adaptations that may be necessary to be within the grasp of a person skilled in the art.

[0097] Those skilled in the art, upon reading this application, will understand that embodiments in many other specific forms than those described in detail are possible without departing from the scope of the invention as claimed. Therefore, the present embodiments should be considered illustrative, but may be modified within the scope defined by the attached claims, and the invention should not be limited to the details given above.

Claims

DEMANDS 1. Optimized expansion bone anchoring implant, comprising: A tubular body (2) extending between a proximal portion (22) having a first internal diameter, and a distal portion (23) having a second internal diameter smaller than said first internal diameter, these two portions defining a longitudinal axis (L) and said first and second internal diameters defining an internal profile of said tubular body (2), and comprising, on the one hand, at least a first thread (20) inside the tubular body (2) and, on the other hand, at least a second thread (21) outside the tubular body (2), A rod (1) extending between a proximal portion (12) and a distal portion (13) on an axis collinear with the axis (L) and having, on the one hand, along said longitudinal axis (L), an external profile complementary to said internal profile of said tubular body (2) and, on the other hand, at least one external thread (11) whose thread pitch is reversed with respect to said second external thread (21) of the tubular body (2), The implant being expandable between, on the one hand, a resting configuration in which a stop mechanism reciprocally locks said tubular body (2) and said rod (1) by reversing their two threads, and, on the other hand, an expanded configuration obtained by the reciprocal actuation of said complementary internal and external threads of the tubular body (2) and the rod (1), causing the rod (1) to penetrate the tubular body (2) and generating the expansion of said tubular body (2), due to the external diameter of the rod (1) being greater than the internal diameter of the tubular body (2), at least over a distal portion, by deformation of the tubular body (2) during the penetration of the rod (1) into the tubular body (2), characterized in that The outer profiles of the rod (1) and the inner profiles of the tubular body (2) are complementary, so that in their expanded configuration they provide: A proximal support point supported by the complementarity of the external diameter of the rod (1) with the internal diameter of the tubular body (2), A distal support point supported by the cooperation between the tubular body (2) whose internal diameter narrows towards the distal portion until it is less than the external diameter of the stem (1), A "central" support point located between these two support points (at the proximal and distal level), formed by the cooperation between the external diameter of the rod (l) and the internal diameter of the tubular body (2) which induce, in expanded configuration, an external diameter of the tubular body (2) at the "central" level which is greater than the external diameter of the tubular body (2) at the level of the proximal support point.

2. Implant according to claim 1, characterized in that said external diameter of the tubular body (2) at the "central" level is greater than the external diameter of the tubular body (2) at the distal support point.

3. Implant according to claim 1, characterized in that the distal support point is formed on at least a portion of the distal portion (23) complementary to the external profile of the stem (1).

4. Implant according to claim 2, characterized in that the distal support point is formed by said distal portion (13) comprising a tip (17) whose external profile is complementary to the internal profile of the distal portion (23) of the tubular body (2).

5. Implant according to any one of claims 1 to 4, characterized in that the central support point is formed by at least one rib (26) projecting inside the tubular body (2), on an intermediate portion between the distal portion (23) and the proximal portion (22), so that said rib (26) cooperates, during expansion, with the outer surface of the stem (1), between its proximal portion (12) and its distal portion (13).

6. Implant according to any one of claims 1 to 5, characterized in that the reciprocating stop mechanism comprises a rib or shoulder or projection inside the tubular body (2), complementary to the outside diameter of the stem (1), or a rib on the inside of the tubular body (2), complementary to a groove or shoulder on the stem (1).

7. Implant according to claim 6, characterized in that the reciprocal stop mechanism comprises a rib (26) projecting inside the tubular body (2) complementary to a shoulder or notch (172) located on the tip of the rod (1).

8. Implant according to claim 7, characterized in that the central support point and the stop mechanism reciprocally locking the tubular body (2) and the rod (1) are formed by the same elements cooperating, respectively, in expanded configuration or in rest configuration.

9. Implant according to the preceding claims taken as a whole, characterized in that the outer diameter of the stem (1) is greater than the inner diameter of the tubular body (2), by at least one constriction (271) on a distal portion.

10. Implant according to claim 9, characterized in that said at least one constriction (271) is located, with respect to the proximal portion and along the longitudinal axis (L), at a distance determined as a function of depth, in the bone tissue, at which said expansion is desired.

11. Implant according to any one of claims 1 to 9, characterized in that the tubular body (2) comprises on its distal portion (23) a frustoconical portion (291) whose internal diameter is less than the external diameter of the stem (1).

12. Implant according to claim 11, characterized in that the frustoconical portion (291) has a thread (232) with a conical core allowing the tubular body (2) to penetrate deeply into the bone.

13. Implant according to the preceding claims taken as a whole, characterized in that the distal portion (23) has self-tapping notches (231).

14. Implant according to claim 11, characterized in that the distal portion (23) has longitudinal opening slots (24) allowing expansion of the tubular body (2).

15. Implant according to claim 13, characterized in that there are as many self-tapping notches (231) as through longitudinal slots (24).

16. Implant according to claim 11, characterized in that the distal portion (23) has non-opening longitudinal slits (25) allowing expansion of the tubular body (2).

17. Implant according to any one of the preceding claims, characterized in that said stem (1) includes at least one distance marker (16) to visualize the moment when the screwing of the stem (1) into the tubular body (2) must be carried out in the opposite direction to the screwing of the tubular body (2) into the bone tissue.

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