HELICAL IMPLANT FOR THE FIXING OF BONE ELEMENTS

Abstract

The purpose of the present invention is a new implant for a medical use enabling the fixing of at least two adjacent bone elements in a rapid, reliable and low-invasive manner. This implant is a device with three distinct parts. The present invention also describes a method for fixing at least two adjacent bone elements implementing this new implant. This method is especially suitable for the solidarization of at least two vertebrae for the realization of an arthrodesis; said implant having a curve shape that makes it particularly well adapted to the spine surgery.

Claims

1. Surgical implant for the fixing of at least two adjacent bone elements of a patient, the surgical implant comprising: i) a rod intended to be inserted first in a drilling (5) made in the at least two adjacent bone elements, ii) at least one distinct helical element intended to be inserted second on said rod that serves as a guide, and iii) a sealing element intended to be injected into space rendered free by the removal of the rod.

2. Surgical implant according to claim 1, wherein the rod presents a curved shape.

3. Surgical implant according to claim 2, wherein the curved shape of the rod is mixed.

4. Surgical implant according to claim 2, wherein the curved shape of the rod is regular.

5. Surgical implant according to claim 1, wherein the rod is carried out in one or several biocompatible flexible materials.

6. Surgical implant according to claim 1, wherein the rod portions positioned outside the bone elements to assemble are flexible.

7. Surgical implant according to claim 1, wherein said sealing element consists of self-grafted bone material, hydroxyapatite collagen, demineralized bone matrix (DBM according to the English Demineralized Bone Matrix), a porous synthetic bone substitute, an osteo-inductant protein or a morphogenic bone protein (BMP according to the English Bone Morphogenic Protein), an acrylic cement, or a combination of these elements.

8. Case or kit composed of a surgical implant according to claim 1.

Description

[0079] The above-mentioned characteristics of the invention, as well as others, will more clearly appear with the reading of the following description of an example of realization, said description referring to the attached figures, among which:

[0080] FIG. 1 represents a view of the rod (1) constituting the part of the surgical implant that is inserted first in the zone of operation;

[0081] FIG. 2 represents a view of said at least one helical element (3) with more particularly a mode of realization made up of only one helical element (FIG. 2a) or a mode of realization made up of two helical elements (FIG. 2b);

[0082] FIG. 3 represents a view of the rod (1) constituting one of the two parts of the surgical implant at the time its will be inserted in the drilling (5) practised in two adjacent vertebrae (7, 8);

[0083] FIG. 4 represents the first part of the surgical implant according to the invention, namely the rod (1) once inserted between two adjacent vertebrae (7, 8). Is also represented said at least one helical element (3) whereas this last slides along the rod (1);

[0084] FIG. 5 represents the surgical implant once positioned between two adjacent vertebrae (7, 8), one sees the rod (1) and the first helical element (3) in its final position, thus serving as a screw within two adjacent vertebral bodies (7, 8);

[0085] FIG. 6 illustrates the withdrawal of the rod (1) once the second helical element (4) in place;

[0086] FIG. 7 represents the injection of the sealing element (10) within the space that was initially occupied by the rod (1).

[0087] This example of installation of an implant according to the invention describes the solidarization of two adjacent vertebrae (7, 8) thanks to a surgical implant such as described above and the use of a sealing element (10). The illustrated embodiment reveals a rod (1) of curved shape and two helical elements (3, 4) that are inserted along the rod (1).

[0088] FIG. 1 illustrates the first element constituting the surgical implant according to the invention, namely the curved rod (1). In this embodiment, the proximal end is in the form of a point. This first element is inserted, generally using a drilling and installation tool, within two adjacent bone elements (7, 8), here two vertebrae.

[0089] FIG. 2 illustrates two embodiments of said at least one helical element (3). On FIG. 2a, it is represented a mode of realization with only one helical element (3) having a form of the type solid central axis drill. On FIG. 2b, it is represented a mode of realization with two helical elements, the first (3) being represented in black and the second (4) being represented in white. In this last mode of realization, the helical elements (3, 4) have a form of the type wire worm, grooved twist thread drill. Of course, these modes of realization are not limitative and are given here only for illustration and clarity purposes.

[0090] FIG. 3 illustrates the rod (1) at the time it will be inserted within the drilling (5) previously realized by the surgeon. The advantage of the curved shape of the rod (1) appears clearly of this figure where one can see the easiness of the implant installation.

[0091] In practise, the rod (1) can be inserted using a drilling and installation tool within the two adjacent bone elements (7, 8), here two vertebrae (toll not represented).

[0092] FIG. 4 shows the rod (1) once positioned within two adjacent vertebral bodies (7, 8) to solidarize. As it also comes out from this figure, a first helical element (3) comes to slide along the rod (1) by an helical movement that is instigated to him by the surgeon, said rod (1) serving then as a guide. While combining this movement with a light pushing, said helical element (3) will come to slide along the rod (1) into the space made up between the external walls of the rod (1) and the internal walls of cavity of the drilling (5).

[0093] FIG. 5 shows the first helical element (3) in its final position within two vertebral bodies (7, 8) along the rod (1).

[0094] The second helical element (4) is then inserted along the rod (1) in the same way as the first element (3) without coming to move this first. This stage is not represented.

[0095] FIG. 6 shows the two helical elements (3, 4) in their final position within the two adjacent vertebral bodies (7, 8) in our example. This figure illustrates also the withdrawal of the rod (1) realized by the surgeon in order for the helical elements (3, 4) to remain in place. This results in a space made free in the middle of the helical elements (3, 4), there even where the rod (1) was. The vertebral pedicles are not affected by the installation of the surgical implant thus one avoids any problem of false way and/or of nervous or vascular lesion.

[0096] FIG. 7 illustrates the surgical implant in its final position. The sealing element (10) is then injected through a syringe (11) or any equivalent device directly within the space made free by the withdrawal of the rod (1). This last will then flow out and fill the whole free space within the helical elements (3, 4). In a preferred manner, this last will be able to flow out outside this space directly in contact with the vertebrae (7, 8). In addition to the fact of solidarizing the implant within the vertebrae, this flow of the sealing element (10) will make it possible to come to fill the osseous spans of the vertebrae (7, 8) and thus to avoid the problems or complications linked to the pseudoarthrosis phenomenon.

[0097] The installation of such a surgical implant according to the invention is typically realized using two distinct tools aimed at positioning very precisely the two elements constituting said surgical implant, namely the rod (1) and said at least one distinct helical element (3, 4). A drilling tool allows practising a drilling (5) in the two bone elements (7, 8) to solidarize according to a way determined by the surgeon. Then a first tool allows the installation of the rod (1), then a second installation tool allow the insertion of the at least one helical element (3, 4) along the rod (1) while instigating a helical movement. The rod (1) previously installed is used as a guide to said at least one helical element (3, 4). According to an additional characteristic it can be envisaged a stop element in order to determine very precisely when said at least one helical element (3, 4) is in its final position. Said stop element can be located either at the distal end of the rod (1), or at its proximal end i.e. on the level of the insertion point of the rod (1) in the first bon element (8).

[0098] When the surgeon judges it applicable in function of the bone elements to assemble and of the material constituting the rod (1), it can be envisaged to use a drilling and installation tool that employs the rod (1) of the surgical implant presenting a pointed distal end as a drilling head. In this mode of realization there is no preliminary stage of drilling when the method according to the invention is applied.

[0099] In order to confer more solidity to the implant it can be envisaged elements in relief, such as pins, on the walls of said at least one helical element (3, 4) oriented in an adequate way to oppose a resistance to unscrewing of said at least one helical element (3, 4) after its installation by the surgeon.

[0100] The present invention concerns also a method for fixing at least two adjacent vertebrae (7, 8) that implements a surgical implant as described above, consisting of a rod (1), at least one distinct helical element (3, 4) and one sealing element (10), said method consisting in:

[0101] to practice by means of a drilling tool a drilling (5) displaying the characteristics defined by the surgeon according to the vertebrae (7, 8) to solidarize, then

[0102] to insert the rod (1) in the drilling (5) thus made by means of a setting tool under medical radioscopy, then to insert each of the at least one distinct helical element (3, 4) on the rod (1) by means of a setting tool allowing to give separately or simultaneously the various components of helical movement to said at least one helical element (3, 4), optionally

[0103] to block said at least one helical element (3, 4) in the desired position using a blocking device, then

[0104] to inject the sealing element (10).

[0105] In the case of spine implantation for an adult patient, the surgical implant according to the invention aimed at solidarizing two vertebrae is of a developed length of 70 mm and curve-shaped following an arc with a 90 mm radius. As a first step a drilling (5) is made with a first drilling tool. Then a setting tool is used in order to place the rod (1) from the cortical through the smooth part of the first vertebral body (8) and finally towards the second vertebral body (7) to be fixed. As a second step said at least one distinct helical element (3, 4) is inserted along the rod (1) by means of a suitable ancillary device allowing its insertion while giving it a helical movement, the rod (1) beforehand placed in the drilling serving as a guide.

[0106] Typically for an adult patient, the rod (1) has a diameter of 6.0 mm. The whole surgical implant requires therefore a drilling (5) of a diameter of about 10.0 mm in all within the two adjacent vertebrae (7, 8) to fix for an adult patient.

[0107] The present invention relates also to cases or kits containing the material necessary to the implementation of the above-described method.

[0108] According to a first embodiment, the present invention concerns cases or kits containing a surgical implant in one of the above-detailed embodiments.

[0109] According to an embodiment, the present invention concerns a case or a kit including a surgical implant as defined.

[0110] According to a second embodiment, the present invention concerns cases or kits including a surgical implant in one of the embodiments detailed above and a drilling tool.

[0111] According to a third embodiment, the present invention is directed to cases or kits including a surgical implant according to one of the embodiments detailed above, a drilling tool, a setting tool for the rod and a setting tool of said at least one helical element allowing its insertion with an helical movement; these three tools forming an ancillary devices kit.

[0112] In a preferred embodiment the case or kit includes a curve shaped surgical implant and an ancillary devices kit.