Easy-to-extract bone anchoring implant

Abstract

The invention relates to a bone anchoring implant that is easy to extract and comprises: - an expandable sleeve (2) which extends between a proximal portion (22) and a distal portion (23) and defines a longitudinal axis (L); a screw (1) which extends between a proximal portion (12) and a distal portion (13) along an axis collinear with axis (L) and has an outer profile complementary to the inner profile of the expandable sleeve (2), said screw (1) comprising at least one distance marker (16) to visualize when the screw (1) has to be screwed into the expandable sleeve (2) in the direction opposite to the screwing direction of the expandable sleeve (2); - the implant moves from a retracted rest position to a deployed position by the penetration of the screw (1) into the expandable sleeve (2); - distal portion (23) comprises self-tapping notches (231), while distal portion (13) comprises a self-cutting head (17).

Description

TECHNICAL FIELD AND OBJECT OF THE INVENTIONThe present invention relates to the field of osseous implants fordental, orthopedic, surgical or osteoplastic applications, such as orthopedicscrews alone or with plates, dental or ligament implants for joints such as forexample the hips, the elbows, the ankles, the shoulders and the knees, orrachidian spinal implants for example for the vertebrae. These fields ofapplication are given by way of example and are not restrictive as to thescope of the present invention.More specifically, the invention relates to an osseous implant whoseimplantation in the porous bone is extremely stable.STATE OF THE ARTAn osseous anchoring implant generally consists of an elongate bodyintended to be implanted in a housing formed in an osseous tissue, such asthe jaw bone for a dental application or in a vertebra for example.It is important that the osseous anchoring implant can be easilyintroduced into the osseous tissue, without creating damage, and that theanchoring device inside the osseous tissue is stable. Indeed, current osseousanchoring implant devices do not allow anchoring without generating morecracks or damage than required for the size of the device itself in theosseous tissue, moreover it is necessary that the fixation in the osseousimplant is reliable and extremely stable, because many therapeutictechniques today rely on bone growth that generally requires that the devicesanchored in the osseous tissue remain as immobile as possible.In addition, it is also necessary that the implantation in the osseoustissue is easy to perform in order to avoid any risk of incorrect positioning ofthe osseous anchoring implant, which could in particular be due to a difficultyin the positioning or in the implantation in the bone.In addition, in the event of a fall, impact or accident, it is important thatthe osseous anchoring implant remains in place in the osseous tissue, that isto say it does not move through the bone. For this, a very high stability of theimplant is necessary.It is also important that the removal of the implant from the osseoustissue where it is implanted is possible and easily achievable, withoutcreating injuries or damage in the osseous tissue.The state of the art comprises the patent document EP2603163 B1,which describes an endosseous implant with improved anchoring able to beimplanted in an osseous tissue and including a fixing device comprising apart called gripping part in the osseous tissue, and a part called expansionpart, these two parts being movable relative to each other. The inventionmentioned in this patent also comprises cooperating mechanical connectionmeans disposed, on the one hand, on the gripping part and, on the otherhand, on the expansion part, such that the relative mobility of the two partscomprises at least one degree of freedom and such that a relativedisplacement of said two parts causes a widening of the gripping part, saidwidening causing the gripping of the gripping part in the osseous tissue. Theosseous implant described in this patent particularly finds application in thedental field.However, such a solution has drawbacks because the osseousimplant, although immobilized in rotation and in translation in the tissue,presents the risk of moving, in particular of receding during an impact,subsequently making its removal less easy.The invention therefore aims at solving these drawbacks by proposingan osseous anchoring implant able to be implanted and immobilized in theosseous tissue in an extremely stable manner, then to be unscrewed andremoved from the osseous tissue if necessary, without creating lesions in theosseous tissue.GENERAL PRESENTATION OF THE INVENTIONThe present invention therefore aims at overcoming the drawbacks ofthe prior art by proposing an osseous anchoring implant, hereinafter calledosseous implant, which is easily implantable in the osseous tissue, stableand also easily removable from the osseous tissue.To achieve this result, the present invention relates to an osseousanchoring implant with facilitated extraction, comprising:An expandable sleeve extending between a proximal portion having afirst internal diameter, and a distal portion having a second internal diametersmaller than said first internal diameter, these two portions defining alongitudinal axis (L) and said first and second internal diameters defining aninternal profile of said expandable sleeve, and comprising, on the one hand,at least a first threading inside the expandable sleeve and, on the other hand,at least a second threading outside the expandable sleeve,A screw extending between a proximal portion and a distal portion onan axis collinear with the axis (L) and having, on the one hand, along saidlongitudinal axis (L), an external profile complementary to said internal profileof said expandable sleeve and, on the other hand, at least one externalthreading whose screw pitch is reversed relative to said second externalthreading of the expandable sleeve,The implant being able to switch from a folded rest position to adeployed position by the actuation of said reversed threadings by causing thepenetration of the screw into the expandable sleeve and generating theexpansion of said expandable sleeve by deformation, thanks to the fact thatthe external diameter of the screw is greater, at least on a distal portion, thansaid second internal diameter of the expandable sleeve,In the deployed position of the implant, the second internal diameter ofthe expandable sleeve being greater than or equal to the first internaldiameter,The distal portion including a head comprising at least one rear flutewith a cutting edge to mill the bone during the extraction of the osseousimplant and facilitate the removal of the implant.According to one feature, the cutting edge of said rear flute has anangle, relative to the longitudinal axis (L), determined by the thread directionof the screw when the implant is removed.According to another feature, the external diameter of the screw isgreater than the internal diameter of the expandable sleeve, by at least oneshrinkage on a distal portion.According to another feature, said at least one shrinkage is located,relative to the proximal portion and along the longitudinal axis (L), at adistance determined as a function of the depth, in the osseous tissue, atwhich said expansion is desired.According to another feature, the implant comprises an outer osseousanchoring threading on a frustoconical portion whose flaring is reversedrelative to the flaring formed by the truncated cone of the sleeve in thedeployed position.According another feature, said expandable sleeve includeslongitudinal through-slots extending up to its distal portion.According another feature, the distal portion of the sleeve is self15tapping due to the fact that it includes at least one notch or flute.According to another feature, there are as many self-tapping notchesor flutes as there are longitudinal through-slots.According to another feature, said expandable sleeve includeslongitudinal non-through slots.According to another feature, said screw comprises at least onedistance marker to visualize the moment when the screwing of the screw inthe expandable sleeve must be carried out in the opposite direction to thescrewing of the expandable sleeve into the osseous tissue.According to another feature, said expandable sleeve is made ofplastic or elastic material.PRESENTATION OF THE FIGURESOther characteristics and advantages of the invention will appear uponreading the detailed description of the embodiments of the invention, givenby way of example only, and with reference to the drawings which show:[Fig. 1a], [Fig. 1b] and [Fig. 2] represent a detailed view of theelements that make up the osseous implant according to the invention.[Fig. 3a] represents a diagram of the sleeve of the osseous implantbefore the expansion according to the invention.[Fig. 3b] represents a diagram of the sleeve of the osseous implantafter the expansion according to the invention.[Fig. 3c] represents a diagram of the osseous implant after theexpansion according to the invention.[Fig. 4a] and [Fig. 4b] represent a view of the interior of the osseousimplant before the expansion of the sleeve according to the invention.[Fig. 5] and [Fig. 6] represent a diagram of the osseous implant afterthe expansion of the sleeve according to the invention.[Fig. 7] and [Fig. 8] represent a diagram of the sleeve in the expandedposition according to the invention.[Fig. 9a] and [Fig. 9b] represent a diagram of the interior of theosseous implant after the expansion of the sleeve according to the invention.[Fig. 10a] and [Fig. 10b] represent a diagram of the interior of thesleeve in the expanded position according to the invention.[Fig. 11] represent a diagram of a cross-section of the interior of theosseous implant, before the expansion according to the invention.[Fig. 12] represents a diagram of the screw tip according to theinvention.DETAILED DESCRIPTION OF ONE EMBODIMENT OF THEINVENTIONVarious embodiments of the invention are described below inparticular with reference to the illustrative and non-limiting figures.The present application relates to the extraction of an osseous implantfrom the osseous tissue.It may happen that the presence of an osseous implant is no longernecessary in the osseous tissue or that it is necessary to take off thisosseous implant.It should be noted here that the term "extraction" designates that factof removing the osseous implant from the osseous tissue, generally byunscrewing, if necessary. The extraction proposed in the present applicationdesignates a removal of this osseous implant from the osseous tissue bylimiting the damage related to this removal, when an ablation is desired.In addition, the term "osseous tissue(s)" generally designates all typesof bones, whether they are compact bones (such as the cortical bone or theperiosteum) or cancellous (soft, porous) bones, because the osseous implantsystem of the present application is implantable in any type of osseoustissue.In addition, the terms used should not be interpreted in their generalmeaning but rather in the light of the functional considerations detailed in thepresent application.[Fig. 1a] and [Fig. 1b] are an illustrative and non-limiting exemplaryembodiment of the osseous implant.As for example represented in [Fig. 1a] to [Fig. 11], an osseousimplant able to be implanted in an osseous tissue comprises an expandablesleeve (2) extending between a proximal portion (22) having a first diameter,and a distal portion (23) having a second diameter, these two portionsdefining a longitudinal axis (L), and comprising, on the one hand, at least afirst threading (20) inside the expandable sleeve (2) and, on the other hand,at least a second threading (21) outside the expandable sleeve (2), saidexpandable sleeve (2) including longitudinal through-slots (24) extending upto its distal portion (23) and self-tapping notches (231), as well as longitudinalnon-through slots (25).In the present application, the term "expandable sleeve (2)" generallydesignates a hollow generalized cylinder.In some embodiments, the osseous implant also comprises a screw(1) extending between a proximal portion (12) and a distal portion (13) on anaxis collinear with the axis (L) and having, on the one hand, along saidlongitudinal axis (L), an external profile complementary to the internal profileof said expandable sleeve (2) and, on the other hand, at least one externalthreading (11) whose screw pitch is reversed relative to said second externalthreading (21) of the expandable sleeve (2), said screw (1) comprising atleast one distance marker (16) to visualize the moment when the screwing ofthe screw (1) in the expandable sleeve (2) must be carried out in the oppositedirection to the screwing the expandable sleeve (2) into the osseous tissueThe terms "proximal" and "distal" designate in the present application,respectively, the part where the implantation device is held to allow itsimplantation in the osseous tissue, and the part which is implanted first in theosseous tissue (opposite the proximal portion).The terms "proximal and distal portions" designate in the presentapplication the parts located in the vicinity of the distal and proximal ends.It should be noted that the proximal portion (12) of the screw (1) isdirectly implanted in the cortical bone.It should also be noted that the osseous implant is made of titanium orof implantable medical stainless steel or of polyetheretherketone (PEEK) orof polyetherketoneketone (PEKK) or any other material of which those skilledin the art can determine the suitability depending on its mechanical, physicochemicalproperties and on its biocompatibility.In some embodiments, the implant is able to switch from a folded restposition to a deployed position by the actuation of said reversed threadingsby causing the penetration of the screw (1) into the expandable sleeve (2)and by generating the expansion of said expandable sleeve (2) bydeformation, thanks to the fact that the external diameter of the screw (1) isgreater than the internal diameter of the expandable sleeve (2) at least on adistal portion. In the deployed position of the implant, the second diameter ofthe expandable sleeve (2) is greater than or equal to the first diameter.In some embodiments, the external diameter of the screw (1) isgreater than the internal diameter of the expandable sleeve, by at least oneshrinkage (271) on a distal portion.In some embodiments, said at least one shrinkage is located, relativeto the proximal portion and along the longitudinal axis (L), at a distancedetermined as a function of the depth, in the osseous tissue, at which saidexpansion is desiredIn some embodiments, the proximal end of the screw (1) comprises anactuating means making it possible to screw the screw (1), said actuatingmeans comprising a structure of any shape desirable by the practitionerdepending on the use which will be made of it, as for example represented in[Fig. 1b]. The actuating means being for example a hexagonal hole or a torxor a cruciform or any other actuating means, and the proximal end of thescrew (1) may have various shapes depending on the desirable destinationfor the osseous anchoring implant (head for fixing a polyaxial or non-polyaxialosteosynthesis bar, or for fixing a plate or any other device).In some embodiments, the screw (1) comprises a cannula passingthrough the screw (1) to allow the practitioner to inject for example cement, ifhe considers it necessary.In some embodiments, the implant also comprises an outer osseousanchoring threading (15) on a frustoconical portion, as represented forexample in [Fig. 1a], [Fig. 1b] and [Fig. 2].The term "osseous anchoring" used in the present applicationgenerally designates various types of devices comprising at least oneelement intended to enter the osseous tissue along a rectilinear path, underthe action of a push generally exerted in the form of repeated screwingoperations, impacts or strikes. It is known that an osseous anchoringthreading has a thread height generally greater than that of a mechanicalthreading to ensure better anchoring. In addition, an osseous anchoringthreading is generally different from a mechanical threading and those skilledin the art know that, depending on the type of bone and desired application, itis possible to vary the diameter of the core, the screw pitch and the wireheight and the present application covers these various embodiments.In some embodiments, the external profile of the screw (1) and theinternal profile of the expandable sleeve (2) are complementary, so that theyprovide, in an expanded configuration:A proximal bearing point supported by the complementarity of theouter diameter of the screw (1) with the inner diameter of the expandablesleeve (2),A distal bearing point supported by the cooperation between theexpandable sleeve (2) whose inner diameter narrows towards the distalportion until becoming smaller than the outer diameter of the screw (1),A "central" bearing point located between these two bearing points,formed by the cooperation between the outer diameter of the screw (1) andthe inner diameter of the expandable sleeve (2) which induce an outerdiameter of the expandable sleeve (2) at the "central" level which is greaterthan the outer diameter of the expandable sleeve (2) at the proximal bearingpoint.In some embodiments, as for example represented in [Fig. 3a], theexpandable sleeve (2) has an acute angle α at the end of its distal portion(23). This angle α opens and increases as the screw (1) enters theexpandable sleeve (2), during the expansion.In some embodiments, as for example represented in [Fig. 3b], theangle α, opening increasingly during the expansion, becomes an angle β, theangle β being the angle of the expanded expandable sleeve (2).It will be noted that in the deployed position, the walls of theexpandable sleeve (2) can in some embodiments be parallel instead ofcreating an angle β.In some embodiments, the expandable sleeve (2) has a domed shapeat the central bearing point, as for example represented in [Fig. 3c], by thepresence of the angles α and β.In some embodiments, as for example represented in [Fig. 3a] to [Fig.3c], [Fig. 5] to [Fig. 8], the expandable sleeve (2) includes longitudinalthrough-slots (24) extending up to its distal portion (23) and longitudinal nonthroughslots (25) allowing the expansion of the expandable sleeve (2). It ispreferable that there are several through (24) or non-through (25) slots, andthat the distal portion (23) includes the two types of slots, that is to saylongitudinal through slots (24) and longitudinal non-through slots (25).In some embodiments, the synergy between the through-slots (24)and the non-through slots (25) also allows truncated cone geometry.In some embodiments, the non-through slots (25) allow theexpandable sleeve (2) to expand in the cancellous osseous tissue bypresenting a domed shape, of the convex type, making it possible tocompress and densify the material over its periphery, thus improving primarystability, healing, and making it possible to avoid the addition of cement tostabilize and immobilize the osseous implant.In some embodiments, there are as many self-tapping notches (231)as there are longitudinal through-slots (24).In some embodiments, the through-slots (24) and the non-throughslots (25) are positioned offset relative to each other over the length of theexpandable sleeve (2). The offset of the through-slots (24) and non-throughslots (25) over the length improves the flexibility and the mechanical strengthof the expandable sleeve (2) during the expansion.In some embodiments, the longitudinal through (24) and non-through(25) slots on the distal portion (23) allow the cylindrical expansion of theexpandable sleeve (2). The longitudinal non-through slots (25) contribute tothe stability of the osseous implant in the osseous tissue by allowing, duringthe expansion, to be able to maintain the contact profile on the three bearingpoints between the expandable sleeve (2) and the screw (1), and by allowingthe forces due to the expansion to be uniformly distributed over the peripheryof the expanded expandable sleeve (2). The longitudinal through (24) andnon-through (25) slots allow a radial expansion of the proximal portion (22) ofthe expandable sleeve (2) by complying with the elastic limit of the material ofthe expandable sleeve (2) and its elastic shrinking during the unscrewing.In some embodiments, said longitudinal through-slots (24) extend over10 to 90 % of the length of the expandable sleeve (2).It should be noted that a bone growth passes through the intersticesinside the osseous implant which consist in the through-slots (24) and thenon-through slots (25). The bone regrowth contributes to the immobilizationand to the stability of the implant in the osseous tissue, but also makes itmore difficult to remove the implant when an ablation is necessary afterseveral months of implantation in the osseous tissue.In some embodiments, the distance marker (16) is a laser marker.In some embodiments, the osseous implant is removed from theosseous tissue, without generating serious lesions or significant cracks in thebone thanks in particular to the elastic deformation of the expandable sleeve(2) within the limit of the e lasticity of the material used.As represented for example in [Fig. 12], the head (17) comprises atleast one notch of the rear flute (171) type for milling the bone, in order to millor tap the bone during the extraction of the osseous implant. Indeed, afterinsertion of the implant in the cancellous part of the bone, the osseous tissueis reformed by becoming harder around the implant and in the interstices leftempty in the slots that have opened and / or between the inner wall of theexpandable sleeve (2) and the outer wall of the screw (1) after the expansion.It is then necessary to mill or tap the hard part of the bone to be able to movethe implant and unscrew it during the extraction, in order to remove theosseous implant.In some embodiments, additional short screwing allows breaking theosseous tissue reformed around the implant in order to unblock the latter,followed by an unscrewing which then allows removing the implant.In some embodiments, during the ablation of the osseous implant, therear flutes (171) allow milling or tapping the bone which has formed betweenthe screw (1) and the expandable sleeve (2), during the receding of thescrew (1) until returning to the rest position in which the external diametersare substantially constant over the entire length of the expandable sleeve (2).This return to constant diameter being automatic when the expandablesleeve (2) has an elastic deformation, while when the expandable sleeve (2)has a plastic deformation, this return to constant diameter will be imposed bythe compression undergone by the expandable sleeve (2) during removal atthe outlet of the duct created by the implant.In some embodiments, the rear flutes (171) have a cutting edge. Thecutting edge of said rear flute (171) has an angle, relative to the longitudinalaxis (L), determined by the thread direction the screw (1) when the implant isremoved.The extraction the osseous implant comprises the following steps:Unscrewing the osseous implant in the direction of the externalthreading (11) until the appearance of the distance marker (16),Locking the implant by a clamp blocking the screw (1) in theexpandable sleeve (2) in the rest position,Unscrewing the implant in the direction of the second threading (21).The osseous implant proposed in the invention can therefore beextracted from the osseous tissue quickly and accurately, its removal beingfacilitated and / or the risks of damaging the bone during its removal beinglimited.The present application describes various technical characteristicsand advantages with reference to the figures and / or to various embodiments.Those skilled in the art will understand that the technical characteristics of agiven embodiment can indeed be combined with characteristics of one ormore other embodiment(s) unless the reverse is explicitly mentioned or thesecharacteristics are incompatible or the combination does not work.More generally, combinations of various types of implant retainingmeans and / or spine retaining means are envisaged and will be appreciatedby those skilled in the art using the functional and structural considerationsprovided in the present application. In addition, the technical characteristicsdescribed in a given embodiment can be isolated from the othercharacteristics of this mode unless the reverse is explicitly mentioned, inparticular because the functional considerations provided in the presentapplication will provide a sufficient explanation so that the structuraladaptations possibly necessary are within the reach of those skilled in the art.Those skilled in the art, upon reading the present application, willunderstand that embodiments in many specific forms other than thosedescribed in detail are possible without departing from the field of applicationof the invention as claimed. Therefore, the present embodiments should beconsidered by way of illustration, but can be modified in the field defined bythe scope of the appended claims, and the invention should not be limited tothe details given above.

Claims

1. An osseous anchoring implant with facilitated extraction, comprising: An expandable sleeve (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 expandable sleeve (2), and comprising, on the one hand, at least a first threading (20) inside the expandable sleeve (2) and, on the other hand, at least a second threading (21) outside the expandable sleeve (2), A screw (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 expandable sleeve (2) and, on the other hand, at least one external threading (11) whose screw pitch is reversed relative to said second external threading (21) of the expandable sleeve (2), The implant being able to switch from a folded rest position to a deployed position by the actuation of said reversed threadings by causing the penetration of the screw (1) into the expandable sleeve (2) and generating the expansion of said expandable sleeve (2) by deformation, thanks to the fact that the external diameter of the screw (1) is greater, at least on a distal portion, than said second internal diameter of the expandable sleeve (2), In the deployed position of the implant, the second internal diameter of the expandable sleeve (2) being greater than or equal to the first internal diameter, Characterized in that The distal portion (13) includes a head (17) comprising at least one rear flute (171) with a cutting edge to mill the bone during the extraction of the osseous implant and facilitate the removal of the implant.

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

3. The implant according to the preceding claims, characterized in that the external diameter of the screw (1) is greater than the internal diameter of the expandable sleeve (2), by at least one shrinkage (271) on a distal portion.

4. The implant according to claim 3, characterized in that said at least one shrinkage (271) is located, relative to the proximal portion and along the longitudinal axis (L), at a distance determined as a function of the depth, in the osseous tissue, at which said expansion is desired.

5. The implant according to claims 1 to 4, characterized in that the implant comprises an outer osseous anchoring threading (15, 152) on a frustoconical portion whose flaring is reversed relative to the flaring formed by the truncated cone of the sleeve (2) in the deployed position.

6. The implant according to the preceding claims, characterized in that said expandable sleeve (2) includes longitudinal through-slots (24) extending up to its distal portion (23).

7. The implant according to the preceding claims, characterized in that the distal portion (23) of the sleeve is self-tapping thanks to the fact that it includes at least one notch or flute (231).

8. The implant according to claims 6 and 7, characterized in that there are as many self-tapping notches or flutes (231) as there are longitudinal through-slots (24).

9. The implant according to the preceding claims, characterized in that said expandable sleeve (2) includes longitudinal non-through slots (25).

10. The implant according to any of the preceding claims, characterized in that the screw (1) comprises at least one distance marker (16) to visualize the moment when the screwing of the screw (1) in the expandable sleeve (2) must be carried out in the opposite direction to the screwing the expandable sleeve (2) into the osseous tissue.

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