WO2020043629A1

WO2020043629A1 - Device for assisting in the reconstruction of a vertebra

Info

Publication number: WO2020043629A1
Application number: PCT/EP2019/072626
Authority: WO
Inventors: Paolo Mangione; Hugues Pascal-Moussellard; Istvan Hovorka
Original assignee: Moovspine
Priority date: 2018-08-27
Filing date: 2019-08-23
Publication date: 2020-03-05
Also published as: FR3085113A1

Abstract

The invention relates to a device for assisting in the reconstruction of a vertebra, comprising an implant (1), the implant comprising a hollow main body (3) with a hermetic proximal portion (4a) which is not externally threaded and which allows, during operation, pedicle anchoring of the implant, and a distal portion (4b) which is intended to be arranged in the vertebral body. The distal portion is formed to allow the interior of the main body and the exterior of the implant to be in contact, and is radially expandable if an element is inserted through the implant.

Description

Aid device for the reconstruction of a vertebra

The present invention relates to a device for assisting in the reconstruction of a vertebra.

STATE OF THE ART

In the field of bone repair, it is known today to use cementoplasty consisting in inserting a filling material into the targeted bone to consolidate it. Applied to the spine, and more particularly to the vertebrae, we also speak of vertebroplasty.

Also known are the techniques related to osteosynthesis consisting of arranging one or more screws in the vertebra. It is thus known to also use the filling material to strengthen the holding of these screws in the vertebra. This is particularly useful in the case of osteoporotic vertebrae.

In both cases there is the problem of leakage of the filling material towards non-targeted areas of the vertebra and in particular in the central canal of the vertebra, also called epidural canal, or else in the intervertebral foramina, within which are found very sensitive elements such as the spinal cord or nerve roots.

This problem is of course aggravated in the case of patients whose vertebrae have a lower bone quality and / or in the case of people suffering from osteoporosis. Furthermore, in the event of osteosynthesis, bone erosion of the vertebra is regularly witnessed around the osteosynthesis screw, leading to the formation of a "lysis chamber" around said screw. There is then a loss of the bone anchorage and the screw ends up contributing itself to the erosion of the vertebra.

In all cases, the pedicle of the vertebra is then weakened, refined, or even non-existent in places, for example in the event of a fracture of the pedicle wall due to parasitic movements of the screw in its lysis chamber, dangerously exposing the spinal cord and the nerve roots to the filling material,

OBJECT OF 1 / INVENTION

An object of the invention is to provide a means to assist in the reconstruction of a vertebra which is more efficient than current devices.

BRIEF STATEMENT OF THE INVENTION

To this end, provision is made, according to the invention, for a device for assisting in the reconstruction of a vertebra comprising an implant, the implant comprising a hollow main body with a hermetic proximal portion which is not externally threaded and intended to be arranged at the level of the pedicle of the vertebra and a distal portion intended to be arranged in the vertebral body, the distal portion being shaped to allow contact between the interior of the main body and the exterior of the implant and being radially expandable if a element is introduced through the implant.

Once the implant is arranged in the vertebra, the proximal portion makes it possible to artificially form part of the pedicle of the vertebra, thus participating in the reconstruction of the vertebra.

The very expansion of the distal portion (either through the introduction of an anchor screw or by any other element, be it the filling material itself or another object such as a balloon) can participate in the reconstruction of 1a vertebra by coming to fill a possible osseous erosion. This expansion results in a radial extension of the distal portion, the length of the implant then varying little or no.

In addition, the proximal portion forms a closed flow channel through which any filler material can flow from outside of 1 implant (and therefore the vertebra) to the distal portion. The implant is thus sealed at the level of the pedicle, making it possible to limit a risk of leakage of the filling material in the pedicle even in the case of weakened, refined or non-existent pedicles. On the other hand, the distal part allows the filling material to reach the vertebral body.

Furthermore, the implant can serve as a guide for a possible anchoring screw which would also participate in the reconstruction of the vertebra.

In the case where an osteosynthesis operation has already been carried out and has led to the formation of a lysis chamber or at least to a loss of bone anchoring of the osteosynthesis screw in the vertebra, said screw can be removed and arrange the implant of the invention instead to assist in the reconstruction of the vertebra (by leaving the implant alone and / or by adding filling material and / or by arranging the same screw or another screw in the implant and / or by causing the implant to expand). It should be noted that the invention is thus advantageously usable with existing screws.

The invention can thus make it possible to participate in the reconstruction of the vertebra in multiple ways and even allow a surgical resumption of a previous mechanically faulty osteosynthesis. Advantageously, the fact that the proximal portion is smooth or quasi-smooth externally prevents the proximal portion from coming to exert too great stresses against the pedicle which is sometimes very fragile.

The invention can thus be used over the long term.

Optionally, the proximal portion is smooth on the outside.

Optionally, at least the distal portion is spiral.

Optionally, one end of the distal portion is open,

Optionally, the proximal portion is also shaped to be expandable if an element is introduced through the implant,

Optionally, the main body is shaped to cooperate with a screw introduced through the implant so as to allow a radial expansion of the distal portion when the screw is screwed and a radial retraction of said distal portion when the said screw is unscrewed.

Optionally, the distal portion has at least one hole.

Optionally, holes are present on each spiral of the distal portion so that several successive holes jointly form at least one flow channel.

Optionally, the proximal portion is extended with a plug provided with depressions and / or reliefs.

Optionally, the main body includes at least one hollow and / or raised area.

Optionally, the main body includes means for anti-rotation of the main body.

Optionally, the main body is internally threaded over all or part of its length.

Optionally, the main body is externally threaded over at least part of its distal portion.

Optionally, the main body is spiraled differently between its distal end and its proximal end.

Optionally, at least the distal portion comprises at least two angular segments jointly forming at least one spiral of the distal portion. Optionally, the device comprises at least three angular segments arranged so that at least in an unexpanded position of the distal portion, each angular segment surrounds externally, over at least part of its circumference, one of the angular segments and either surrounded externally, on at least part of its circumference, by another of the angular segments.

Optionally, at least one external surface of the distal portion is provided with teeth.

Optionally, the spirals of the main body have an increasing thickness in the direction of a free end of the distal portion.

Optionally, the main body extends straight.

Optionally, the device comprises at least two implants.

Optionally, the device includes a connector allowing the two implants to be joined together.

Optionally, the device also includes an anchoring screw capable of being inserted into the implant.

Optionally, the main body is generally shaped into a cylinder or a cone when it is not deformed.

Other characteristics and advantages of the invention will emerge on reading the following description of particular non-limiting embodiments of the invention.

BRIEF DESCRIPTION OF THE FIGURES

Reference will be made to the appended drawings, among which:

FIG. 1 is a perspective view of an implant of a device for assisting in the reconstruction of a vertebra according to a first embodiment of The invention;

- Figures 2a and 2b are cross-sectional views and Figure 2c is a longitudinal sectional view of the implant illustrated in Figure 1;

- Figure 3 is a view similar to that of Figure 2c, a screw of the device being arranged inside the implant;

FIG. 4 is a view similar to that of FIG. 3, the implant and the screw being in place on a vertebra,

- Figure 5 is a cross-sectional view of a variant of the implant illustrated in Figure 1;

- Figure 6 is a perspective view of an implant of a device to assist in the reconstruction of a vertebra according to a second embodiment of the invention;

- Figure 7 is a perspective view of part of an implant of a device for assisting in the reconstruction of a vertebra according to a third embodiment of the invention;

- Figures 8a and 8b are perspective views of an implant of a device to assist in the reconstruction of a vertebra according to a fourth embodiment of the invention respectively without and with the screw arranged inside the implant;

- Figure 9 is a perspective view of an implant of a device to assist in the reconstruction of a vertebra according to a fifth embodiment of the invention;

- Figures 10a, 10b, 10c illustrate different variants of an implant of a device to assist in the reconstruction of a vertebra according to a sixth embodiment of the invention;

- Figure 11 is a perspective view of an implant of a device to assist in the reconstruction of a vertebra according to a seventh embodiment of

1 / invention;

FIGS. 12a and 12b are perspective views of an implant of a device for assisting in the reconstruction of a vertebra according to an eighth embodiment of the invention respectively when the main body is in its folded position and in its service position;

- Figure 13 is a perspective view of an implant of a device to assist in the reconstruction of a vertebra according to a ninth embodiment of the invention, the implant being in place on a vertebra;

FIG. 14 is a perspective view of two implants and of a connection between the two implants of a device for assisting in the reconstruction of a vertebra according to a tenth embodiment of the invention, the two implants and the fitting being in place on a vertebra,

FIGS. 15a and 15b are perspective views of an implant of a device for assisting in the reconstruction of a vertebra according to an eleventh embodiment of the invention respectively when the main body is in its folded position and in its service position,

FIGS. 16a and 16b are perspective views of an implant of a device for assisting in the reconstruction of a vertebra according to a twelfth embodiment of the invention respectively when the main body is in its folded position and in its service position,

FIGS. 17a and 17b are perspective views of an implant of a device for assisting in the reconstruction of a vertebra according to a thirteenth embodiment of the invention respectively when the main body is in its folded position and in his service position.

DETAILED DESCRIPTION OF 1 / INVENTION In the figures are shown only the parts of the spine useful for the description of the invention or the parts which do not interfere with the visibility of the invention.

With reference to FIGS. 1 to 4, the device for assisting in the reconstruction of a vertebra according to a first embodiment of the invention comprises a hollow implant 1. The implant 1 thus comprises an orifice 2 passing through it.

The implant 1 is for example of metallic material for example of a metallic alloy or of a single metal, such as titanium or of titanium alloy, or else of plastic material such as polyetheretherketone (better known by the acronym PEEK) or in polyetherketonetone, (better known by the acronym PEKK) or in any other biocompatible or absorbable material and for example in PLLA-PGA.

Such an implant 1 has for example a length at least equal to 20 millimeters and typically a length between 20 and 60 millimeters, and for example a length between 20 and 45 millimeters.

Such an implant 1 typically has an external diameter of between 3 and 10 millimeters and preferably between 4 and 9 millimeters.

The implant 1 comprising a main body 3 which here extends in a rectilinear fashion in an axial direction X, By “rectilinear”, it is meant that the main body 3 is not curved, i.e. that it is straight.

The orifice 2 is formed in the main body 3, coaxial with the axial direction X so that the main body 3 is hollow.

The main body 3 comprises two portions which are in one piece or which are each formed of a independent part, the two parts then being fixed to each other for example by welding, by gluing, etc .;

a proximal portion 4a intended to extend at least in part into the pedicle of the target vertebra, a portion which may also be called the pedicle portion, and

a distal portion 4b intended to extend out of said pedicle but into the vertebral body, a portion which may also be called intracorporeal portion,

The proximal portion 4a is thus defined to allow pedicle anchoring of the implant 1. It is noted that the proximal portion 4a already participates in the reconstruction of the vertebra especially when the pedicle is damaged, the proximal portion 4a itself simulating the pedicle as more visible in Figure 4.

Preferably, the external surface of the proximal portion 4a is smooth.

This reinforces this simulation, in particular avoiding the implant 1 from eroding the pedicle still in place too easily,

In particular, the external surface of the proximal portion 4a is not threaded.

In the present case, the external surface of the main body 3 is smooth over its entire height. Furthermore, the implant 1 is shaped to allow a flow of filling material from the outside of the vertebra into the vertebral body. .

To this end, the proximal portion 4a is hermetic, that is to say that there is no possible communication between the orifice 2 and the outside of the implant 1 via the proximal portion. 4a,

This prevents the filling material from escaping through the proximal portion 4a, which would be dangerous for the spinal cord and / or the nerve roots. On the other hand, the distal portion 4b is shaped to allow a connection between the orifice 2 and the outside of the implant 1,

In the present case, the distal portion 4b is open at its free end. The orifice 2 thus opens out at the two ends of the main body 3.

Furthermore, the main body 3 is shaped so that at least the distal portion 4b is radially expandable if an element is introduced into the orifice 2 of the implant 1 (such as a screw 5). In the present case, the proximal portion 4a is not radially expandable even when the element is introduced into the orifice 2 of the implant 1.

Preferably, the main body 3 is spiraled from the free end of the distal portion 4b to substantially the level of the beginning of the proximal portion 4a which is thus not spiraled. Consequently, the main body 3 is spiraled differently between its distal end and its proximal end.

Thus in the proximal portion 4a, the main body 3 is completely closed ensuring the tightness of this portion (as illustrated in FIG. 2a) while in the distal portion 4b, the main body 3 forms a serpentine able to extend radially. (as illustrated in Figure 2b). Typically the coil has between one and three spirals and preferably between two and three spirals.

Externally, the main body 3 is thus substantially shaped into a cylinder. When the implant 1 is in its initial position, the external diameter of the cylinder is substantially identical over the entire length (in the axial direction X) of the main body 3.

On the other hand, because the main body 3 is more spiraled as one approaches the free end of the distal portion 4b, the diameter of 1 / orifice 2 is greater at the level of the proximal portion 4a than at the level of the distal portion 4b.

This facilitates the radial expansion of the distal portion 4b while ensuring the sealing of the proximal portion 4a when an element is introduced into the orifice 2. In the present case, the entire proximal portion 4a (does not deform radially when inserting a screw 5 into the implant 1.

The main body 3 is also shaped so that the diameter of the orifice 2 at the distal portion 4b is less than that of the screw 5 intended to be introduced into the implant 1. Of course, the diameter of the the orifice 2 at the level of the proximal portion 4a is greater than or equal to, and preferably substantially equal to, that of said screw 5.

Thus, in service, if the screw 5 does not modify the structure of the proximal portion 4a, it causes, at the distal portion 4b, a radial expansion of said distal portion 4b as is more visible in FIG. 3 and in FIG. 4.

This ensures good retention of the implant 1 in place, the main body 3 being more difficult to be torn from the vertebra.

In addition, this also promotes reconstruction of the vertebra, the expansion of the implant 1 making it possible to fill the bone space possibly present at this location.

The distal portion 4b is for example formed of a sheet wound on itself so that the spirals are arranged inside the main body 3 thus naturally allowing to reduce the diameter of the orifice 2. For example l the thickness of the sheet gradually increases until the free end of the distal portion 4b.

The upper end of the proximal portion 4a is extended by a plug 6 of the implant 1 which is in one piece with the main body 3 or else attached and fixed to the main body 3.

The plug 6 is preferably of a diameter greater than that of the external portion of the proximal portion 4a in order to jointly delimit a collar.

The collar ensures a limitation of a relative movement between the proximal portion 4a and the vertebra, in particular during the introduction of the screw 5, by coming to bear in service against or in the bone.

In service, the implant 1 is introduced into the vertebra. This can be done either in an impacted manner or else in a screwed manner.

Once the implant 1 is arranged in the vertebra, the proximal portion 4a extending at the level of the pedicle and the distal portion 4b at the level of the vertebral body, it is possible to introduce filling material into the vertebral body through the intermediary of implant 1 which thus acts as a veritable canal closed from the outside of the vertebra to the vertebral body. The filling material is for example a cement, such as a biological or absorbable cement, a resin, or even a mixture of different components.

We can replace or complement a screw 5 through the implant 1, screw 5 which will advantageously extend radially the distal portion 4b reinforcing the anchoring of the device in the vertebra.

A device has thus been proposed which is simple to manufacture and to implement. It is further noted that the implant 1 of such a device is applicable to the various existing screws already on the market.

According to a preferred variant, the main body 3 is shaped to extend radially when the screw 5 is screwed and to retract when unscrewing the screw 5. In this way, the coil formed by the main body 3 loosens during the introduction of the screw 5 and tightens during a possible withdrawal of the screw 5.

This is particularly advantageous if one wishes to be able to keep the option of removing the screw 5 and the implant 1.

To this end, the orifice 2 is provided with a thread (not visible here) capable of cooperating with that of the screw 5 to allow expansion-screwing and retraction-unscrewing of the main body 3,

As a variant or in addition, as visible in FIG. 5, the orifice 2 is provided with stops 16 (here two in number) extending in the orifice 2 and capable of cooperating with the screw 5 to allow an expansion-screwing and a retraction-unscrewing of the main body 3.

Referring to Figure 6, while in the first embodiment of the invention the main body 3 having no holes, in this second embodiment of the invention, the distal portion 4b has holes 7 (including one only part is referenced here) formed at least in the outermost spiral and preferably in one, several or all of the internal spirals.

This facilitates the flow of the filling material out of the implant 1.

In addition, this makes it possible to soften the distal portion 4b concerned, the thickness of which can sometimes be significant, which can possibly hinder the radial expansion of said distal portion 4b.

In addition, once the filling material has been poured, it thus constitutes, jointly with the implant 1, an additional anti-tearing function of the implant 1.

Preferably, the holes 7 are present on each spiral so that several successive holes 7 (in the radial direction) jointly form flow channels 8 of the filling material from the orifice 2 into the vertebral body.

When the screw 5 is introduced it deforms the distal portion 4b potentially shifting the holes from each other and thus eliminating these flow channels 8. However this is not a problem if the filling material has already been poured.

Preferably, the holes 7 have a larger and larger diameter as one approaches the free end of the distal portion 4b.

In the axial direction X, the different holes 7 extend for example one after the other so as to form lines extending axially, the different lines being distributed homogeneously over the circumference of the main body 3.

Here, the lines extend over at least part of the distal portion 4b. Preferably, the lines extend over the entire length of the distal portion 4b.

The lines do not extend outside the distal portion 4b.

While in the first embodiment of the invention the collar was smooth, in the third embodiment of 1 / invention, the collar is provided with recesses and / or reliefs. For example, the face of the flange facing the main body 3 is rough. As a variant, as illustrated in FIG. 7, the flange has teeth 9 (only a part of which is referenced here) at its face facing the main body 3. The different teeth 9 are here homogeneously distributed over the circumference of the relevant face of the collar.

This non-smooth appearance of the flange limits even more a risk of relative displacement between the proximal portion 4a and the vertebra by allowing better attachment of the implant 1 on the bone material of the vertebra. In particular, these recesses and / or bumps fulfill the role of anti-rotation of the implant 1.

This anti-rotation function can, in addition or as a replacement, be provided in another way. Thus, with reference to FIGS. 8a and 8b and according to a fourth embodiment of the invention, the main body 3 is provided around its periphery. external of slots 10 (only a part of which is referenced here).

Each slot 10 extends axially, in the axial direction X, the various slots 10 being moreover distributed homogeneously over the circumference of the main body 3.

Typically, the main body 3 has slots 10 arranged at least on the outermost spiral of said main body 3, optional, said slots 10 are also arranged on one, several or all of the internal spirals of said main body 3. Each slot 10 thus forms a cut across the entire thickness of at least one spiral or even across the entire thickness of the main body 3.

The slots 10 extend here over at least part of the distal portion 4b. Preferably, the slots 10 extend over the entire length of the distal portion 4b.

The slots 10 do not extend out of the distal portion 4b.

Furthermore, the width of the slots 10 here gradually increases towards the free end of the distal portion 4b.

In this way, when the distal portion 4b extends radially, the tongues 10 '(of which only a part is referenced here) of the distal portion 4b delimited by two consecutive slots 10 open in corole filling an anti-rotation action.

In addition, this makes it possible to facilitate the radial expansion of the distal portion 4b. This is particularly advantageous in the case where the thickness of the spirals increases as one approaches the free end of the distal portion 4b, the increase in thickness resulting in an increase in the rigidity of the main body 3 and therefore a decrease in the deformability of said main body 3.

With reference to FIG. 9, and according to a fifth embodiment of the invention, while in the first embodiment of the invention the external periphery of the main body 3 was smooth, the external periphery of the main body 3 here comprises stop tabs 11 (only part of which is referenced}.

This further limits the risk of the implant being torn away 1.

Note that these stop tabs 11 also fulfill an anti-rotation function, in the same way as the teeth 9 of the third embodiment of the invention or the tongues 10 'of the fourth embodiment of the invention .

These stop tabs 11 are for example in the form of pointed lugs which makes it possible to accentuate this anti-rotation function.

The different stop tabs 11 extend for example one after the other so as to form lines extending axially, in the radial direction X, the different lines being distributed homogeneously over the circumference of the main body 3.

The main body 3 here comprises stop lugs 11 formed on the outermost spiral. As a variant or in addition, the stop lugs 11 are formed on one, several or all of the internal spirals of the main body 3,

The stop tabs 11 extend over at least part of the distal portion 4b. Preferably, the stop lugs li extend over the entire length of the distal portion 4b.

The stop tabs 11 do not extend out of the distal portion 4b.

Figures 10a, 10b and 10c illustrate different variants of a sixth embodiment of the invention.

The main body 3 typically has grooves 12a, 12b formed on its outermost spiral. As a variant or in addition, said grooves 12a, 12b are formed on one, more or all of the internal spirals of the implant 1. By groove is meant a cut that does not extend throughout the entire thickness of a spiral and a fortiori throughout the thickness of the main body 3.

This facilitates the radial expansion of the distal portion 4b. This is particularly advantageous in the case where the thickness of the spirals increases as one approaches the free end of the distal portion 4b, the increase in thickness resulting in an increase in rigidity of the main body 3 and therefore a reduction in the deformability of said main body 3.

It is noted that these grooves 12a, 12b also fulfill an anti-rotation function, in the same way as the teeth 9 of the third embodiment of the invention or the tongues 10 'of the fourth embodiment of the invention in promoting the radial expansion of the main body 3.

In all cases, the grooves 12a, 12b extend over at least part of the distal portion 4b. Preferably, the grooves 12a, 12b extend over the entire length of the distal portion 4b.

The grooves 12a, 12b do not extend out of the distal portion 4b.

Preferably, the grooves 12a are distributed homogeneously over the main body 3.

Referring to Figure 10a, the grooves 12a extend axially.

Referring to Figure 10b, the grooves 12b extend circumferentially.

Referring to Figure 10c, the grooves extend both axially (grooves 12a) and circumferentially (grooves 12b).

Of course, other softeners of the main body 3 that the grooves 12a, 12b can be envisaged, such as for example bores, holes, etc. The grooves 12a, 12b can also take other forms and / or directions than what has been indicated. We can thus have zigzag grooves.

As visible in FIG. 11, and according to a seventh embodiment of the invention, while in the first embodiment of the invention the external periphery of the main body 3 was smooth, the external periphery of the main body 3 is here threaded.

The thread 13 extends for example at least partially over the distal portion 4b and preferably over the entire distal portion 4b. The thread does not, however, extend over the proximal portion 4a,

This is particularly advantageous in the case where the implant 1 is screwed into the vertebra.

It should be noted that the thread 13 advantageously makes it possible to further limit the risk of the implant 1 being torn away from the vertebra. The implant 1 remains here shaped so that the insertion of a screw 5 in the implant 1 always allows to increase radially the free end of the distal portion 4b.

The main body 3 typically comprises a thread 13 formed on its outermost spiral. As a variant or in addition, the thread 13 is also formed on one, several or all of the internal spirals of the implant 1.

In an eighth embodiment of the invention, and as shown in FIGS. 12a and 12b, the sheet forming at least the distal portion 4b has the same thickness over its entire surface.

The sheet, however, has an increasingly large width as we approach the free end of the distal portion 4b. In this way, when the sheet is wound on itself, the distal portion 4b is formed by a greater number of spirals at its free end than at its end fixed to the rest of the main body 3. Thus, the main body 3 is spiraled differently between its distal end and its proximal end.

Here again the sheet is wound towards the inside of the main body 3.

This promotes the radial expansion of the distal portion 4b of the implant 1.

As illustrated in FIG. 13, and according to a ninth embodiment of the invention, the main body 3 is not rectilinear.

The main body 3 is on the contrary curved.

The main body 3 can be naturally curved (so as to present this shape at rest) or else be flexible enough to follow the shape of a curved receiving channel formed in the vertebra for receiving the implant 1 (the main body 3 not necessarily having a curved shape at rest).

This is particularly interesting in the case of poor preparation of the vertebra for reception of the implant 1 or in the case where the vertebra has too bad a bone structure to allow a rectilinear passage of the implant 1 in the pedicle.

Alternatively, the main body 3 can take a shape other than straight or curved. The main body 3 can thus take an S shape. The shape of the main body 3 in the vertebra is thus adapted according to the needs of the patient.

FIG. 14 illustrates a tenth embodiment of 1 / invention in which the device comprises more than one implant,

Typically the device comprises two implants 1, l 'which are identical and arranged on either side of the spinous process of the same vertebra in a substantially symmetrical manner with respect to the axis of said spinous process.

This further limits the risk of the device tearing off by distributing the forces undergone between the two implants 1, l '.

Preferably, the device comprises a connector for linking the two implants 1, one of them.

For example, each plug 6, 6 ′ of each implant 1, l ′ comprises a connection tab 14, 14 ′ and the connector 15 connects the two tabs 14, 14 ′ therebetween thus joining the two implants 1 ′.

The connector 15 can in particular secure the two implants 1, by screwing, by gluing, by clamp, by snap-fastening, by interlocking ...

As a variant or in addition, the device may comprise a greater number of implants than what has been indicated and / or the implants may be different from each other and / or the implants may be arranged differently and for example not be arranged on the same vertebra or be arranged on the same side of a vertebra.

Figures 15a and 15b illustrate an eleventh embodiment. In this embodiment, the main body 3 is also spiraled differently between its distal end and its proximal end.

In the present case, only the distal portion 4b is spiraled.

While in the above embodiments, the spirals were continuous, in the present case the spirals are discontinuous. Thus, the distal portion 4b comprises at least two and preferably at least three angular segments jointly forming the spirals of the distal portion 4b, the angular segments being able to move relative to each other. Optionally, the distal portion 4b comprises at least four angular segments, the angular segments being able to move relative to each other.

With such an architecture, there is a risk of the bone entering the main body 3 during the radial expansion of the distal portion 4b.

In the present case, the distal portion 4b has three angular segments 17a, 17b, 17c which can slide circumferentially relative to each other.

Each angular segment is shaped here so as to present a section (along a section plane of normal to the X axis) in a ring segment. Each angular segment extends circumferentially over a portion of an angle between 150 and 250 degrees, and preferably between 180 and 230 degrees and more preferably between 190 and 220 degrees.

Thus, as can be seen in FIG. 15a, in the folded position, the three angular segments 17a, 17b, 17c are entangled with one another so as to jointly form at least two spirals. So each angular segment surrounds on the outside, on at least part of its circumference, one of the two remaining of the angular segments and is surrounded on the outside, on at least part of its circumference, by the other of the two remaining of the angular segments. Typically, the overlapping of two angular segments is done over an angle portion between 90 and 180 degrees and preferably 100 to 140 degrees.

As visible in FIG. 15b, during the introduction of a screw 5, the different 17a, 17b, 17c will slide relative to each other so as to allow a radial expansion of the distal portion 4b. In this position, preferably, each angular segment surrounds on the outside, on at least part of its circumference, one of the two remaining of the angular segments and is surrounded on the outside, on at least part of its circumference, by the other of the two remaining angular segments. The overlapping of two angular segments is then made over a portion of an angle between 3 and 35 degrees and preferably between 5 and 30 degrees and more preferably between 5 and 25 degrees.

In this position, the angular segments 17a, 17b and 17c still jointly form a spiral.

Optionally, the angular segments 17a, 17b, 17c are shaped so as to be compressed in part by the angular segment surrounding it externally in the unexpanded position. For example, the angular segments 17a, 17b and 17c are made of an elastically deformable material allowing this compression.

This facilitates the expansion of the distal portion

4b in which the angular segments 17a, 17b and 17c are no longer or only slightly compressed.

Figures 16a and 16b illustrate a twelfth embodiment. The only difference from the eleventh embodiment is the shape of the angular segments. The angular segments 17a, 17b and 17c thus no longer have a section in a ring segment. The angular segments 17a, 17b and 17c are such that, in the unfolded position, the section of each segment has a central part 18 extended at its two ends by enlarged portions 19, 20.

The angular segments 17a, 17b and 17c are moreover arranged one inside the other (as in the eleventh embodiment) so that:

in the folded position, the distal portion 4b has a generally circular external surface and an internal orifice of generally circular section,

- In the service position, the distal portion 4b has a generally triangular external surface and an internal orifice of generally circular section.

Such a configuration promotes the radial expansion of the distal portion 4b which thus offers a larger diameter once the different angular segments are spaced from each other.

Figures 17a and 17b illustrate a twelfth embodiment.

The only difference with the eleventh embodiment is that the external surface of the different angular segments is not smooth. At least one of the angular segments, and preferably all the angular segments 17a, 17b and 17c, thus has a hole and / or teeth.

As illustrated in FIG. 17a, preferably if the angular segments 17a, 17b and 17c have teeth on the outside, these will extend over an external contour of the angular segments so that in the folded position, the teeth extend over the entire outer circumference of the distal portion 4b.

In the service position, as visible in FIG. 17b, the external contour of the distal portion 4b has alternating smooth areas and tooth areas.

Of course, the invention is not limited to the embodiments described but encompasses any variant coming within the scope of the invention as defined by the claims.

In particular, we can mix the different embodiments described. For example, the implant may include both orifices as in the second embodiment and both teeth at the flange as in the third embodiment. It will thus be possible to mix different anti-tearing and / or relative anti-movement elements (such as anti-rotation elements).

The implant can simply be used without inserting filling material and / or without using anchoring screws. The device can thus be formed in certain embodiments of the implant alone. The implant is thus very adaptable to the targeted reconstruction, the implant can just as easily be a dowel for an anchor screw, as a channel for a filling material, as a full-fledged reconstructor playing the same role than an osteosynthesis screw, one of the functions not excluding the other.

In the same way, the radial expansion of the implant can be done in many ways either by a screw, or by a filling material, or by another element such as a balloon for example.

The device may include other elements than what has been indicated. For example, the device could include a gripper to hold the implant during its introduction into the vertebra then during the introduction of the screw into the implant (gripper can optionally be articulated and / or automated) and / or a syringe for introduce the filling material into the implant and / or an arm to introduce the screw in the implant (arm can optionally be articulated and / or automated) ... The screw can also be part of the device.

As already indicated, the implant is suitable for receiving any type of screw (length, diameter, type of thread, etc.) and in particular to the screws already existing on the market. The device according to the invention can thus be presented as a kit which complements any type of pedicle instrumentation already existing such as the existing osteosynthesis screws (whether the device comprises only the implant or whether it comprises other elements) or as a universal recovery kit.

The implant may possibly include a tongue for attachment to another element of the device, a tongue which can then possibly be cut if only the implant (and potentially the screw) remains in place on the vertebra.

Furthermore, the free end of the distal portion may not be open but be closed. The contact between the orifice and the exterior _s ^? will then perform for example through holes, slits

Although the proximal portion here retains its external diameter when an element is introduced through the implant, the proximal portion can be shaped like the distal portion so as to be radially expandable if an element is introduced through the implant. The entire main body can thus be radially expandable if an element is introduced through the implant. It may be envisaged that the proximal portion has a less substantial radial extension than that of the distal portion. In all cases, the proximal portion will always be airtight. For example, the proximal portion may be made of an elastically deformable material. The proximal portion may be very tightly spiraled so as to allow only a slight radial extension of the proximal portion. We can secure with dots of adhesive or adhesive the adhesion between the spirals of the proximal portion. The proximal portion may include grooves (that is to say not extending over the entire thickness of the proximal portion in order to keep this portion sealed). The proximal portion may also, if it is spiral, have slots on its outermost spirals only.

It is noted that both the proximal portion and the distal portion can be spiraled. The entire main body can thus be spiraled. A single sheet can thus form the main body alone. However, to ensure the sealing of the proximal portion, the spirals will preferably be different between the proximal end and the distal end (tighter, thicker, more numerous, in a less flexible material, etc.).

In the same way, although here the proximal portion has always been presented as being externally smooth, the proximal portion may not be completely smooth and for example include recessed and / or raised areas. For example, the proximal portion may have very fine grooves so that, without the introduction of an element through them, the grooves are barely perceptible, the introduction of the element, however, causing a radial extension of the authorized proximal portion. by an opening of the grooves then more visible.

Although here the main body has the external shape of a cylinder in the non-deformed state, that is to say with an external diameter substantially identical over its entire length, the main body may have another shape even at the undeformed state. The body main can thus naturally flare towards the free end of the distal end so as to generally form a cone, the external diameter of the main body then increasing towards the free end. In the same way, although here the radial expansion of the implant results in a widening of the implant in the direction of the free end of the distal end so as to form a cone overall, the implant can be shaped to deform in another way, for example with a spherical deformation centered or not centered on the distal portion.

If the main body is partially or entirely spiraled, it may have a different number of spirals and / or angular segments than what has been indicated.

In the case of angular segments, these may be different from what has been indicated. For example, a different number of angular segments than what has been indicated may be used. The angular segments may overlap at portions of angles different from what has been indicated (in the expanded or unexpanded position). The angular segments may not overlap in the expanded position. The angular segments may not be made of elastically deformable material.

Claims

1. Device for assisting in the reconstruction of a vertebra comprising an implant (1), the implant comprising a hollow main body (3) with a hermetic proximal portion (4a) not externally threaded intended to be arranged in the pedicle of the vertebra and a distal portion (4b) intended to be arranged in the vertebral body, the distal portion being shaped to allow contact between the interior of the main body and the exterior of the implant and being radially expandable if an element is introduced through the implant,

2. Device according to claim 1, wherein the proximal portion (4a) is smooth on the outside.

3. Device according to one of the preceding claims, in which the distal portion comprises at least one hole (7).

4. Device according to one of the preceding claims, in which at least the distal portion (4b) is spiraled.

5. Device according to claim 4, in which holes (7) are present on each spiral of the distal portion so that several successive holes jointly form at least one flow channel (8).

6. Device according to claim 4 or claim 5, wherein the spirals of the main body (3) have an increasing thickness towards a free end of the distal portion.

7. Device according to one of the preceding claims, in which the main body (3) is spiraled differently between its distal end and its proximal end.

8. Device according to one of the preceding claims wherein at least the distal portion (4b) comprises at least two angular segments jointly forming at least one spiral of the distal portion.

9. Device according to claim 8, in comprising at least three angular segments arranged so that at least in an unexpanded position of the distal portion (4a), each angular segment surrounds externally, over at least part of its circumference, one of the angular segments and is surrounded externally, over at least part of its circumference, by another of the angular segments.

10. Device according to one of the preceding claims, in which at least one external surface of the distal portion (4a) is provided with teeth.

11. Device according to one of the preceding claims, in which one end of the distal portion (4b) is open.

12. Device according to one of the preceding claims, in which the proximal portion (4a) is also shaped to be expandable if an element is introduced through the implant.

13. Device according to one of the preceding claims, in which the main body (3) is shaped to cooperate with a screw (5) introduced through the implant so as to allow a radial expansion of the distal portion during the screwing of the screw and a radial retraction of said distal portion during the unscrewing of said screw.

14. Device according to one of the preceding claims, wherein the proximal portion (4a) is extended by a plug (6) provided with depressions and / or reliefs.

15. Device according to claim 11, in which the main body (3) comprises anti-rotation means of the main body.