Easily removable bone-anchored implant

Abstract

Easily removable bone implants The present invention relates to an easily removable bone fixation implant, said implant comprising: an expandable sleeve (2) extending between a proximal portion (22) and a distal portion (23), the expandable sleeve defining a longitudinal axis (L); a screw (1) having an outer profile complementary to the inner profile of said expandable sleeve (2), extending between a proximal portion (12) and a distal portion (13) on an axis collinear with the axis (L), said screw (1) comprising at least one distance marker (16) for visualizing the point at which the screw (1) must be threaded into said expandable sleeve (2) in the opposite direction to the threading of said expandable sleeve (2); The implant is switched from a collapsed rest position to a deployed position by the threading of the screw (1) into the expandable sleeve (2), The distal portion (23) includes a self-tapping notch (231); The distal portion (13) includes a self-milling head (17).

Description

[Technical field]

[0001] The present invention relates to the field of bone implants for dental, orthopedic, surgical or osteoplastic applications, with orthopedic screws alone or with plates, for example dental or ligament implants for joints such as hip, elbow, ankle, shoulder and knee, or spinal bone implants for example for vertebrae. These fields of application are given as examples and do not limit the scope of the invention.

[0002] More specifically, the present invention relates to a bone implant that is highly stable when implanted into porous bone. [Background technology]

[0003] Bone anchoring implants generally consist of an elongated body intended to be implanted within a housing formed in bone tissue, such as the jawbone or vertebrae, for dental applications.

[0004] It is important that bone fixation implants can be easily introduced into bone tissue without causing damage and that the fixation device in the bone tissue is stable. In fact, current bone fixation implant devices cannot be fixed in the bone tissue without causing more cracks or damage than is required for the size of the device itself. Furthermore, fixation of the bone implant needs to be reliable and very stable, since many of today's treatment techniques currently rely on bone growth, which requires that the device fixed in the bone tissue be as immobile as possible.

[0005] Furthermore, it is also necessary that the implantation into the bone tissue is easy to carry out, in particular to avoid the risk of incorrect positioning of the bone anchoring implant which may result from positioning or implantation in the bone.

[0006] Furthermore, in case of a fall, impact or accident, it is important that the bone anchoring implant stays in place in the bone tissue, i.e. does not move through the bone. For this reason the implant needs to be very stable.

[0007] It is also important that removal of the implant from the bone tissue in which it is implanted be possible and easily accomplished without causing injury or damage to the bone tissue.

[0008] The state of the art includes patent document EP 2603163 (B1), which describes an intraosseous implant with improved fixation that can be implanted in bone tissue, which comprises a fixation device with a part in the bone tissue called the gripping part and a part called the expansion part, these two parts being relatively movable. The invention referred to in this patent also comprises cooperating mechanical connection means arranged on the one hand on the gripping part and on the other hand on the expansion part, so that the relative movement of the two parts has at least one degree of freedom, and the relative displacement of the two parts causes the gripping part to expand, which causes it to grip in the bone tissue. The bone implant described in this patent is particularly found in applications in the dental field.

[0009] However, such a solution has the drawback that although the bone implant is fixed against rotation and translation in the tissue, it presents the risk of moving during impact, and in particular of retracting, and subsequently becoming difficult to remove.

[0010] The present invention therefore aims to overcome these drawbacks by proposing a bone fixation implant which can be implanted in bone tissue and fixed in a very stable manner and which, if necessary, can be loosened and removed from the bone tissue without causing damage to the latter. Summary of the Invention

[0011] The present invention therefore aims to overcome the drawbacks of the prior art by proposing a bone fixation implant, hereinafter referred to as a bone implant, which can be easily and stably implanted in bone tissue and easily removed from the bone tissue.

[0012] To achieve this result, the present invention relates to an easily extractable bone fixation implant, said bone fixation implant comprising: an expandable sleeve extending between a proximal portion having a first inner diameter and a distal portion having a second inner diameter smaller than the first inner diameter, the two portions defining a longitudinal axis (L), the first and second inner diameters defining an inner profile of the expandable sleeve, the expandable sleeve comprising, on the one hand, at least a first thread on the inside of the expandable sleeve and, on the other hand, at least a second thread on the outside of the expandable sleeve; a screw extending between a proximal portion and a distal portion on an axis collinear with an axis (L), the screw having, on the one hand, an outer profile complementary to the inner profile of the expandable sleeve along said longitudinal axis (L) and, on the other hand, at least one outer thread whose thread pitch is reversed relative to said second outer thread of the expandable sleeve, the implant can be switched from a folded rest position to a deployed position by actuation of the reverse threads by threading the screw into the expandable sleeve and expanding the expandable sleeve by deformation due to the fact that the outer diameter of the screw is larger than the second inner diameter of the expandable sleeve, at least in the distal portion; In a deployed position of the implant, the second inner diameter of the expandable sleeve is greater than or equal to the first inner diameter; The distal portion includes a head with at least one rear groove with a cutting edge for scraping bone during extraction of the bone implant to facilitate removal of the implant.

[0013] According to one feature, the cutting edge of the rear groove has an angle relative to the longitudinal axis (L) that is determined by the thread direction of the screw when the implant is removed.

[0014] According to another feature, the outer diameter of the screw is greater than the inner diameter of the expandable sleeve by means of at least one constriction in the distal portion.

[0015] According to another characteristic, the at least one constriction is located at a distance relative to the proximal portion and along the longitudinal axis (L) determined depending on the depth in the bone tissue to which expansion is desired.

[0016] According to another feature, the implant comprises an outer bone anchoring thread on a frustoconical portion, the extent of which is inverted relative to the extent formed by the frustocone of the sleeve in the deployed position.

[0017] According to another feature, the expandable sleeve includes a longitudinal through slot extending to a distal portion thereof.

[0018] According to another feature, the distal portion of the sleeve is self-tapping by virtue of including at least one notch or groove.

[0019] According to another feature, there are as many self-tapping notches as there are longitudinal through slots.

[0020] According to another feature, the expandable sleeve includes a longitudinal blind slot.

[0021] According to another feature, the screw is provided with at least one distance marker for visualizing the point at which the screwing of the screw into the expandable sleeve must be performed in the opposite direction to the screwing of the expandable sleeve into the bone tissue.

[0022] According to another feature, the expandable sleeve is made of a plastic or elastic material. [Brief description of the drawings]

[0023] Other characteristics and advantages of the invention will become apparent on reading the detailed description of an embodiment of the invention, given by way of example only, and on referring to the following drawings, in which: [Figure 1a] 1 shows a detailed view of the elements that make up the bone implant according to the invention; [Figure 1b]1 shows a detailed view of the elements that make up the bone implant according to the invention; [Diagram 2] 1 shows a detailed view of the elements that make up the bone implant according to the invention; [Figure 3a] FIG. 2 shows a view of a sleeve of a bone implant according to the invention before expansion. [Figure 3b] 1 shows a view of a sleeve of a bone implant according to the invention after expansion. [Figure 3c] FIG. 2 shows a view of a bone implant according to the invention after expansion. [Figure 4a] FIG. 2 shows an internal view of a bone implant according to the invention before expansion of the sleeve. [Figure 4b] FIG. 2 shows an internal view of a bone implant according to the invention before expansion of the sleeve. [Diagram 5] 1 shows a view of the bone implant according to the invention after expansion of the sleeve. [Figure 6] 1 shows a view of the bone implant according to the invention after expansion of the sleeve. [Figure 7] 1 shows a view of a sleeve in an expanded position according to the present invention. [Figure 8] 1 shows a view of a sleeve in an expanded position according to the present invention. [Figure 9a] 1 shows an internal view of the bone implant according to the invention after expansion of the sleeve. [Figure 9b] 1 shows an internal view of the bone implant according to the invention after expansion of the sleeve. [Figure 10a] 1 shows an internal view of a sleeve in an expanded position according to the present invention. [Figure 10b] 1 shows an internal view of a sleeve in an expanded position according to the present invention. [Figure 11] FIG. 2 shows a cross-sectional view of the interior of a bone implant according to the present invention before expansion. [Figure 12] 1 shows a view of the tip of a screw according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Various embodiments of the invention will now be described with particular reference to the illustrative and non-limiting drawings in which:

[0025] The present application also relates to the extraction of a bone implant from bone tissue.

[0026] Circumstances may arise where the presence of a bone implant in bone tissue is no longer required or where it becomes necessary to remove this bone implant.

[0027] It should be noted that in this specification, the term "extraction" refers to the fact of removing the bone implant from the bone tissue, essentially by unscrewing it when necessary. Extraction as proposed in this application refers to removing this bone implant from the bone tissue when ablation is desired, by limiting the damage associated with this removal.

[0028] In addition, the term "bone tissue(s)" generally refers to all types of bone, whether dense (cortical or periosteum) or cancellous (soft, porous) bone, since the bone implant system of the present application can be implanted in any type of bone tissue.

[0029] Furthermore, the terms used should not be interpreted in their ordinary sense, but rather in light of the functional considerations detailed in this application.

[0030] 1a and 1b are illustrative and non-limiting exemplary embodiments of a bone implant.

[0031] For example, as shown in Figures 1a-11, a bone implant that can be implanted in bone tissue comprises an expandable sleeve (2) extending between a proximal portion (22) having a first diameter and a distal portion (23) having a second diameter, these two portions defining a longitudinal axis (L), the expandable sleeve (2) comprising, on the one hand, at least a first thread (20) on the inside of the expandable sleeve (2) and, on the other hand, at least a second thread (21) on the outside of the expandable sleeve (2), the expandable sleeve (2) including a longitudinal through slot (24) and a self-tapping notch (231) extending to its distal portion (23) as well as a longitudinal non-through slot (25).

[0032] In this application, the term "expandable sleeve (2)" generally refers to a hollow, generally cylindrical body.

[0033] In some embodiments, the bone implant also comprises a screw (1) extending between a proximal portion (12) and a distal portion (13) on an axis collinear with an axis (L), the screw (1) having, on the one hand, an outer profile complementary to the inner profile of the expandable sleeve (2) along said longitudinal axis (L) and, on the other hand, at least one outer thread (11) whose thread pitch is reversed relative to said second outer thread (21) of the expandable sleeve (2), the screw (1) comprising at least one distance marker (16) for visualizing the point at which the screwing of the screw (1) into the expandable sleeve (2) must be performed in the opposite direction to the screwing of the expandable sleeve (2) into the bone tissue.

[0034] The terms "proximal" and "distal" in this application refer, respectively, to the portion where the implantation device is held to allow implantation in bone tissue and the portion that is initially implanted in bone tissue (opposite the proximal portion).

[0035] The terms "proximal and distal portions" in this application refer to portions located near the distal and proximal ends.

[0036] Note that the proximal portion (12) of the screw (1) is implanted directly into the cortical bone.

[0037] It should be noted that the bone implants are made of titanium or implantable medical grade stainless steel, or polyetheretherketone (PEEK), or polyetherketoneketone (PEKK), or any other material whose suitability a person skilled in the art can determine depending on its mechanical and physicochemical properties as well as biocompatibility.

[0038] In some embodiments, the implant can be switched from a folded rest position to a deployed position by actuation of said reverse threads by threading the screw (1) into the expandable sleeve (2) and expanding the expandable sleeve (2) by deformation due to the fact that the outer diameter of the screw (1) is larger than the inner diameter of the expandable sleeve (2), at least in the distal portion. In the deployed position of the implant, the second diameter of the expandable sleeve (2) is equal to or larger than the first diameter.

[0039] In some embodiments, the outer diameter of the screw (1) is larger than the inner diameter of the expandable sleeve by at least one constriction (271) in the distal portion.

[0040] In some embodiments, the at least one constriction is located at a distance relative to the proximal portion and along the longitudinal axis (L) that is determined depending on the depth into the bone tissue to which expansion is desired.

[0041] In some embodiments, the proximal end of the screw (1) is provided with an actuation means that allows the screw (1) to be screwed in, said actuation means having any shape structure desired by the practitioner depending on its use, for example as shown in Fig. 1b. The actuation means is for example a hexagonal hole or a torx or a cross or any other actuation means, and the proximal end of the screw (1) can have various shapes (heads for fixing polyaxial or non-polyaxial osteosynthesis bars, or for fixing plates or any other device) depending on the desired destination of the bone fixation implant.

[0042] In some embodiments, the screw (1) is provided with a cannula passing through the screw (1) that allows the practitioner to, for example, inject cement, if desired.

[0043] In some embodiments, the implant also includes an external bone anchoring thread (15) on the frusto-conical portion, as depicted, for example, in FIGS. 1a, 1b, and 2.

[0044] The term "bone fixation" as used in this application refers to various types of devices that include at least one element intended to enter bone tissue along a linear path, generally under a compressive action in the form of a repetitive screwing action, impact, or blow. It is known that bone fixation screws generally have a higher thread height than mechanical screws to ensure better fixation. In addition, bone fixation screws are generally different from mechanical screws, and a person skilled in the art can vary the core diameter, thread pitch, and wire height depending on the type of bone and the desired application, and the present application encompasses these various embodiments.

[0045] In some embodiments, the outer profile of the screw (1) and the inner profile of the expandable sleeve (2) are complementary, such that in the expanded configuration, a proximal bearing point supported by the complementarity of the inner diameter of the expandable sleeve (2) and the outer diameter of the screw (1); a distal bearing point supported by cooperation with an expandable sleeve (2) narrowing towards its distal portion until the inner diameter of the expandable sleeve is smaller than the outer diameter of the screw (1); and a "central" bearing point located between the two bearing points and formed by cooperation between the outer diameter of the screw (1) and the inner diameter of the expandable sleeve (2), thereby causing the outer diameter of the expandable sleeve (2) at the "central" position to be larger than the outer diameter of the expandable sleeve (2) at the proximal bearing point.

[0046] In some embodiments, for example as shown in Figure 3a, the expandable sleeve (2) has an acute angle α at the end of the distal portion (23), which angle α widens and increases as the screw (1) enters the expandable sleeve (2) during expansion.

[0047] In some embodiments, for example as shown in FIG. 3b, angle α gradually becomes flaring angle β during expansion, angle β being the angle of the expanded expandable sleeve (2).

[0048] It should be noted that in the deployed position, the walls of the expandable sleeve (2) may in some embodiments be parallel instead of at an angle β.

[0049] In some embodiments, the expandable sleeve (2) has a dome shape at the central bearing point due to the presence of angles α and β, as shown, for example, in FIG. 3c.

[0050] In some embodiments, for example as shown in Figures 3a-3c, 5-8, the expandable sleeve (2) includes longitudinal through slots (24) that extend to its distal portion (23) and longitudinal non-through slots (25) that allow expansion of the expandable sleeve (2). It is preferred that there are several through slots (24) or non-through slots (25), and that the distal portion (23) includes two types of slots: longitudinal through slots (24) and longitudinal non-through slots (25).

[0051] In some embodiments, the synergy between the through slots (24) and the non-through slots (25) also allows for a frusto-conical shape.

[0052] In some embodiments, the blind slots (25) allow the expandable sleeve (2) to expand within the cancellous bone tissue by assuming a convex dome shape, thereby allowing for compression and strengthening of the material around the circumference of the expandable sleeve (2), improving basic stability and healing and avoiding the need for additional cement to stabilize and secure the bone implant.

[0053] In some embodiments, there are as many self-tapping notches (231) as there are longitudinal through slots (24).

[0054] In some embodiments, the through slots (24) and the non-through slots (25) are offset relative to one another over the length of the expandable sleeve (2). The offset of the through slots (24) and the non-through slots (25) over the length improves the flexibility and mechanical strength of the expandable sleeve (2) during expansion.

[0055] In some embodiments, the longitudinal through slots (24) and the non-through slots (25) on the distal portion (23) allow for cylindrical expansion of the expandable sleeve (2). The longitudinal non-through slots (25) allow for maintaining a contact profile on three bearing points between the expandable sleeve (2) and the screw (1) during expansion, and contribute to the stability of the bone implant in the bone tissue by distributing the expansion forces evenly around the circumference of the expanded expandable sleeve (2). The longitudinal through slots (24) and the non-through slots (25) allow for radial expansion of the proximal portion (22) of the expandable sleeve (2) by accommodating the elastic limit of the material of the expandable sleeve (2) and its elastic contraction during unscrewing.

[0056] In some embodiments, the longitudinal through slot (24) extends over 10-90% of the length of the expandable sleeve (2).

[0057] It should be noted that bone regrowth passes through gaps within the bone implant, configured within through slots 24 and non-through slots 25. Bone regrowth not only contributes to fixation and stability of the implant within the bone tissue, but also makes the implant less likely to be removed if ablation becomes necessary several months after implantation in the bone tissue.

[0058] In some embodiments, the distance marker (16) is a laser marker.

[0059] In some embodiments, the bone implant is removed from the bone tissue without causing serious damage or large cracks to the bone, particularly by elastic deformation of the expandable sleeve (2) within the elastic limits of the material used.

[0060] For example, as shown in Fig. 12, the head (17) comprises at least one notch of the type of rear groove (171) for scraping the bone in order to scrape or tap the bone during the extraction of the bone implant. Indeed, after inserting the implant into the cancellous part of the bone, the bone tissue reforms by becoming harder around the implant and in the open slots and / or in the gaps left open between the inner wall of the expandable sleeve (2) and the outer wall of the screw (1) after expansion. Then, in order to remove the bone implant, it is necessary to be able to scrape or tap the hard parts of the bone to move the implant and loosen the screw during extraction.

[0061] In some embodiments, an additional short screw thread allows for disruption of the remodeled bone tissue around the implant to clear the obstruction, after which the screw can be loosened and the implant can then be removed.

[0062] In some embodiments, during ablation of the bone implant, the rear groove (171) allows to scrape or tap the bone formed between the screw (1) and the expandable sleeve (2) while the screw (1) is retracted until it returns to a rest position where the outer diameter is substantially constant over the entire length of the expandable sleeve (2). This return to a constant diameter is automatic when the expandable sleeve (2) has an elastic deformation, whereas when the expandable sleeve (2) has a plastic deformation, this return to a constant diameter is caused by the compression that the expandable sleeve (2) experiences at the exit of the duct created by the implant during removal.

[0063] In some embodiments, the rear groove (171) has a cutting edge that has an angle relative to the longitudinal axis (L) that is determined by the thread orientation of the screw (1) when the implant is removed.

[0064] Extraction of bone implants unscrewing the bone implant in the direction of the outer thread (11) until the distance marker (16) appears; locking the implant by a clamp blocking the screw (1) of the expandable sleeve (2) in a rest position; and unscrewing the implant in the direction of the second thread (21).

[0065] Thus, the bone implant proposed in the present invention can be quickly and precisely extracted from the bone tissue, its removal is easy and / or the risk of damaging the bone during its removal is limited.

[0066] This application describes various technical features and advantages with reference to drawings and / or various embodiments. Those skilled in the art will appreciate that, in fact, the technical features of a given embodiment may be combined with the features of one or more other embodiments, unless expressly stated to the contrary or unless those features are incompatible or the combination is inoperative.

[0067] More generally, combinations of various types of implant retention means and / or spinal retention means are contemplated and will be understood by those skilled in the art using the functional and structural considerations provided herein. Moreover, technical features described in a given embodiment may be separated from other features of the mode unless expressly stated to the contrary, particularly since the functional considerations provided herein provide sufficient description such that structural adaptations that may be required are within the scope of practice of the skilled artisan.

[0068] Those skilled in the art will understand, upon reading this application, that many specific forms of embodiment other than those specifically described are possible without departing from the scope of the invention as claimed. The present embodiment should therefore be considered as an example, but can be modified in the field defined by the appended claims, and the invention should not be limited to the above details.

Claims

1. An easily removable bone fixation implant, an expandable sleeve (2) extending between a proximal portion (22) having a first inner diameter and a distal portion (23) having a second inner diameter smaller than said first inner diameter, said proximal and distal portions defining a longitudinal axis (L), said first and second inner diameters defining an inner profile of said expandable sleeve (2), said expandable sleeve (2) comprising, on the one hand, at least a first thread (20) on the inside of said expandable sleeve (2) and, on the other hand, at least a second thread (21) on the outside of said expandable sleeve (2); a screw (1) extending between a proximal portion (12) and a distal portion (13) on an axis collinear with said longitudinal axis (L), the screw (1) having, on the one hand, an outer profile complementary to the inner profile of said expandable sleeve (2) in a portion along said longitudinal axis (L), and, on the other hand, at least one outer thread (11) whose thread pitch is reversed with respect to said second thread (21) of said expandable sleeve (2), the bone fixation implant can be switched from a folded rest position to a deployed position by actuation of the reverse thread, by passing the screw (1) into the expandable sleeve (2) and expanding the expandable sleeve (2) by deformation due to the fact that the outer diameter of the screw (1), at least in its distal part, is larger than the second inner diameter of the expandable sleeve (2); In the deployed position of the bone fixation implant, the second inner diameter of the expandable sleeve (2) is equal to or greater than the first inner diameter. In bone-anchored implants that are easily removable, The expandable sleeve (2) is provided with an open slot, characterized in that the distal portion (13) of the screw (1) comprises a head (17) with at least one rear groove (171) having a cutting edge for scraping the bone during extraction of the bone fixation implant and facilitating removal of the bone fixation implant. Bone fixation implant.

2. 2. The bone fixation implant according to claim 1, characterized in that the cutting edge of the rear groove (171) has an angle with respect to the longitudinal axis (L) determined by the thread direction of the screw (1) when the bone fixation implant is removed.

3. 3. The bone fixation implant according to claim 1 or 2, characterized in that the outer diameter of the screw (1) is larger than the inner diameter of the expandable sleeve (2) at at least one contraction (271) in the distal part of the expandable sleeve (2).

4. 4. The bone fixation implant according to claim 3, characterized in that the at least one constriction (271) is located at a distance relative to the proximal part of the expandable sleeve (2) and along the longitudinal axis (L) determined depending on the depth in the bone tissue to which the expansion is desired.

5. 5. The bone fixation implant according to any one of claims 1 to 4, characterized in that the bone fixation implant comprises an outer bone fixation thread (15, 152) on a frustoconical portion of the screw (1), the extent of which is inverted relative to the extent formed by the frustoconical portion of the expandable sleeve (2) in the deployed position.

6. The bone fixation implant according to any one of claims 1 to 5, characterized in that the expandable sleeve (2) comprises a longitudinal through slot (24) extending to the distal portion (23) of the expandable sleeve (2).

7. The bone fixation implant according to any one of claims 1 to 6, characterized in that the distal portion (23) of the expandable sleeve (2) is self-tapping by virtue of the fact that it comprises at least one notch or groove (231).

8. A bone fixation implant as described in claim 6 or 7, characterized in that the expandable sleeve (2) has the same number of self-tapping notches or grooves (231) as there are longitudinal through slots (24).

9. Bone anchoring implant according to any one of the preceding claims, characterized in that the expandable sleeve (2) comprises longitudinal blind slots (25).

10. The bone fixation implant according to any one of claims 1 to 9, characterized in that the screw (1) comprises at least one distance marker (16) for visualizing the point in time at which the screwing of the screw (1) into the expandable sleeve (2) must be performed in the opposite direction to the screwing of the expandable sleeve (2) into the bone tissue.

11. Bone anchoring implant according to any one of the preceding claims, characterized in that the expandable sleeve (2) is made of plastic or elastic material.

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