FR3089110A1 - Device for straightening and stabilizing a spine - Google Patents

Abstract

Device for straightening and stabilizing a spine. Device for straightening and stabilizing a spine, implantable surgically, comprising one or more bars (3), pedicle implants (1) each carrying a connection element (2) making it possible to connect a pedicle implant (1) to a bar (3), and comprising means (20) for cooperation with said implant (1) and means (21) for cooperation with a bar (3). The means of cooperation with a bar (3) is in the form of a hook (21) in the form of a C, the internal wall of which delimits the recess describes a portion of a circle with a diameter corresponding to that of the bar. (3), and according to an angular sector greater than 180 °, namely between 184.7 ° and 188.5 °, the wall (26) extending on the side opposite the free edge (27) of the hook (21) by an oblique pan. Figure for the abstract: Fig. 5

Description

Description

Title of the invention: Device for straightening and stabilizing a spine The present invention relates to a device for straightening and stabilizing a spine, which can be implanted surgically.

A device for straightening and stabilizing a spine comprises, generally in known manner, on the one hand pedicle implants, intended to be implanted in each of the two pedicles of the vertebrae to be fitted, and comprising at their proximal end a connection element, and on the other hand two bars which connect for one the implants aligned on one side of said column, and for the other the implants aligned on the other side of said column, being integral therewith fixedly through said connection elements, so as to join together the fitted vertebrae, and thus force the spine to take a certain curvature, and / or to maintain a constant spacing between adjacent vertebrae, depending on the nature of the intervention .

The connection elements can be in several forms, so there are those which, consisting of two assemblable parts, completely surround the bar, and those which have a hook intended to receive the bar closely while it comes to bear. on part of the pedicle implant.

The establishment of the bars presents certain difficulties, especially when these are not straight, but have a certain camber and curvatures.

On the other hand, all the parts of a device are held in the end when the screws and nuts are tightened, but until reaching this result it may happen that the parts previously put in place disassemble needing to start over.

The present invention aims to provide a device for straightening and stabilizing a spine, which can be implanted surgically, and more particularly a connection element of such a device, making it possible to remedy these drawbacks.

The device for straightening and stabilizing a spine, which can be implanted surgically, according to the invention, comprises one or more bars, pedicle implants each carrying a connection element making it possible to connect a pedicle implant to a bar, and comprising a means of cooperation with said implant and a means of cooperation with a bar, and it is characterized in that said means of cooperation with a bar, is in the form of a C-shaped hook whose internal wall which delimits the recess describes a portion of a circle with a diameter corresponding to that of said bar, and according to an angular sector greater than 180 °, namely between 184.7 ° and 188.5 °, said wall extending on the side opposite the free edge of said hook by an oblique face.

Because the internal wall of the recess of the middle part is a circle which extends over a development greater than 180 °, the opening thus created is retentive, and the insertion of the bar requires be made in force from the inside to the outside, sliding on the tangent wall, while the free edge has enough elasticity so that the hard point can be crossed.

According to an additional characteristic of the device according to the invention, the means of cooperation with a bar has several parts of distinct configurations, namely at least three parts perpendicular to the axis of passage of said bar, on the one hand a middle part whose internal wall which delimits the recess describes a portion of a circle with a diameter corresponding to that of said bar, and according to an angular sector greater than 180 °, namely between 184.7 ° and 188.5 ° , and on the other hand two external parts, which extend said median part as well as its recess, which each comprise a recess extending that of said median part, and whose internal wall has a frustoconical shape so that said recess widens towards the exterior from that of said middle portion.

The flaring of the recess of each of the outer parts allows that there is no hard point to cross, and also that the bar can be curved or arched. According to another additional characteristic of the device according to the invention, the oblique pan is connected to the internal wall which delimits the recess by a curved portion of radius of curvature greater than that of said recess, and to which said oblique pan is tangent.

According to another additional characteristic of the device according to the invention, it comprises two means of cooperation with a bar, diametrically opposite to maintain two bars in parallel.

The advantages and characteristics of the device according to the invention will become more apparent from the description which follows and which relates to the attached drawing, which represents several non-limiting embodiments.

In the accompanying drawing:

[Fig-1] shows a schematic perspective view of a device for straightening and stabilizing a spine, according to the invention.

[Fig.2] shows an elevational view with partial section of the same device.

[Fig.3] shows a sectional view of part of the same device.

[Fig.4] shows a partial schematic view of the same part.

[Fig.5] shows a partial elevational view with partial section of a variant of the device according to the invention.

[Fig.6] shows a view with partial section of a part of the same variant.

[Fig-7] shows a schematic perspective view of an evolution of the same device.

Referring to Figures 1 and 2 we can see a device for straightening and stabilizing a spine, implantable surgically according to the invention.

The straightening device shown comprises a pedicle implant 1, a connection means 2 and a bar 3 partially shown in Figure 1.

The pedicle implant has a threaded distal part 10, surmounted by a head 11, visible in Figure 2, itself extended by a threaded rod 12.

The connection means 2 an annular element 20 extended radially by a hook 21. The annular element 20 has a hole 22 through which is introduced the threaded rod 12, while a nut 4 is screwed onto the latter for tighten the connection means against the head 11.

The hook 21 is arranged and dimensioned to accommodate the bar 3, and to be able to tighten and immobilize the latter against the head 11, when tightening the nut 4.

It will be noted that the hole 22 of the annular element 21 has, at each of its orifices, a chamfer, 23 and 24, in the form of a spherical cap which is congruent with, respectively, the head 11 and the nut 4, which are of complementary forms.

Referring to Figures 3 and 4, we can see more precisely that the hook 21 has a recess 25 for receiving the bar 3, not shown in Figure

3, that this recess 25 is delimited by a wall 26 in the form of a portion of a circle extending over an angular sector greater than 180 ° at an angle a visible in the figure

4, extended on the side opposite the free end 27, that is to say on the side of the hole 22, by an oblique face 28.

The diameter of the circle is barely greater than that of the bar 3, so that the introduction thereof into the recess 25, along the inclined face 28 requires an effort to pass a hard point on the side from the free end 27, thanks to the elasticity of the material. Therefore, after passing the hard point, the recess 25 becomes retentive of the bar 3, while allowing its axial sliding, before having to tighten the nut 4. The angle a must be between 4.7 ° and 8.5 °, depending of course on the diameters of the bar 3 and the recess 25.

Thus for a bar 3 of diameter equal to 5.5 mm the diameter of the recess 25 is 5.6 mm, and the angle a is preferably equal to 6.5 °.

Note that preferably, the oblique face 28 is not directly tangent to the recess 25, since between them is interposed a curved portion 29, between points A and B of Figure 4, radius larger than that of the recess 25, and which facilitates the insertion of the bar 3.

Note that it is possible to obtain the retention of the bar with a bar with a diameter smaller than that of the recess, with a width of opening of the hook smaller than the diameter of the bar , but with less maintenance due to the possible transverse mobility of the bar in the recess.

Referring now to Figures 5 and 6, we can see a variant of the present invention.

As is more particularly visible in Figure 5, the hook 21 is divided in the transverse direction, that is to say along the axis of passage XX 'of passage of the bar 3, visible on FIG. 4, in three parts, a middle part 5, and two outer parts 6, symmetrical with respect to the middle part 5.

The middle part 5 extends over a certain width and has all the characteristics of the hook 21 of Figures 2 and 3, namely a recess 50 defined by a wall 51 in the form of a portion of a circle extending over a sector angular greater than 180 °, extended, on the side opposite the free end 52, by a non-visible oblique face.

The two outer parts 6 each have a recess 60, in the extension of the recess 50, and whose inner wall 61 is of frustoconical shape, so as to flare outward.

According to this embodiment, the hook 21 makes it possible to receive and retain curved or arched bars, without their being maintained at the intermediate part 5.

Referring now to Figure 7, we can see an embodiment of the device according to the invention where the holding means 2 has two hooks 21 for securing two bars 3.

Claims (1)

[Claim 1] [Claim 2] [Claim 3] [Claim 4] Claims Surgical implantable straightening and stabilization device for a spine, comprising one or more bars (3), pedicle implants (1) each carrying a connection element (2) enabling a pedicle implant (1) to be connected to a bar (3), and comprising means (20) for cooperation with said implant (1) and means (21) for cooperation with a bar (3), characterized in that said means for cooperation with a bar, is present under the shape of a C-shaped hook (21) whose internal wall (26) which delimits the recess (25) describes a portion of a circle with a diameter corresponding to that of said bar (3), and according to a angular sector greater than 180 °, namely between 184.7 ° and 188.5 °, said wall (26) extending on the side opposite to the free edge (27) of said hook (21) by an oblique face (28). Straightening device according to claim 1, characterized in that the means (21) for cooperation with a bar (3) has several parts of distinct configurations, namely at least three parts (5; 6) perpendicular to the axis (XX ') passage of said bar (3), on the one hand a middle part (5) whose internal wall (51) which delimits the recess (50) describes a portion of a circle with a diameter corresponding to that of said bar (3), and in an angular sector greater than 180 °, namely between 184.7 ° and 188.5 °, and on the other hand two external parts (6), which extend said middle part (5) as well that its recess (50), which each comprise a recess (60) extending that of said central part (5), and whose internal wall (61) has a frustoconical shape so that said recess (60) widens towards the outside from that of said middle part (5). Straightening device according to claim 1 or claim 2, characterized in that the oblique face (28) is connected to the internal wall (26; 51) which delimits the recess (25; 50) by a curved portion (29) of radius of curvature greater than that of said recess (25; 50), and to which said oblique face (28) is tangent. Straightening device according to any one of claims 1 to 3, characterized in that it comprises two means (21) for cooperation with a bar (3), diametrically opposite to maintain two bars (3) in parallel.