WO2000041635A1

WO2000041635A1 - Implant with support marker and instrument for setting same

Info

Publication number: WO2000041635A1
Application number: PCT/FR2000/000064
Authority: WO
Inventors: Georges Bettega; Jean-Lou Giraud
Original assignee: Aesculap
Priority date: 1999-01-18
Filing date: 2000-01-14
Publication date: 2000-07-20
Also published as: FR2788428B1; EP1143866A1; FR2788428A1

Abstract

The invention concerns an implant (2) designed to receive a marker, comprising a body (8), a first jaw (16) integral with said body, a second jaw (44) mobile relative to said body and means for moving (38) said second jaw (44) from a position spaced from the first jaw (16) towards a position closer to said first jaw (16), said moving means (38) capable of being actuated by a setting instrument (4) detachable with respect to said implant, said implant (2) further comprising means (24, 36) for removably fixing a support (6) of said marker. Said implant, once it has been fixed on a bone part, has very reduced space requirement.

Description

IMPLANT WITH MARKER SUPPORT AND LAYING TOOL

The present invention relates to a surgical implant intended to receive a marker, a positioning tool for this implant, a marker support intended to be attached to this implant, as well as a surgical kit comprising this implant, this tool and this support.

When performing certain surgical procedures, it is necessary to move a piece of bone relative to a so-called reference bone element. Such displacement can be followed, if necessary, by a return of the bone piece considered in its initial position.

In order to ensure that this movement has been carried out correctly, it is essential to know the position and the orientation of the bone piece with respect to the reference bone element, both before and after the movement considered.

To this end, it is known to have, on the bone piece, a marker making it possible to know, in the reference frame of the reference element, the position and the orientation of this bone piece, namely for example its Cartesian coordinates and polar. Such a marker can for example be of an optical or even magnetic nature.

The attachment of this marker to the bone piece to be moved is ensured by means of an implant screwed into this bone piece and comprising a support rod intended to receive, in a removable manner, the marker in question.

This known solution has a drawback, however, insofar as the support rod with which the implant is provided is bulky and therefore proves to be inconvenient for the surgeon. This problem is particularly acute when the operative field is of reduced dimensions, in particular in the case of maxillofacial surgery, where it is necessary to move a bone piece called condyle, the access of which is delicate since it is located at the bottom of the oral cavity.

In order to overcome these various drawbacks, the invention proposes to produce a surgical implant which can be reliably secured to a bone piece, which, once put in place, only disturbs the surgeon to a small extent and which can receive a marker removably and in repeatable positions and orientations.

To this end, the subject of the invention is a surgical implant, intended to receive a marker, characterized in that it comprises a body, a first jaw secured to said body, a second jaw movable relative to said body and means of movement. of said second jaw from a position remote from the first jaw towards a position close to this first jaw, said displacement means being able to be actuated by a positioning tool removable relative to said implant, said implant further comprising removable fixing means for 'a support for said marker.

According to other characteristics of the invention:

- The displacement means comprise a threaded member cooperating with a threaded hole formed in the body, said member being adapted to come, by a first end, bearing against the second jaw so as to bring it closer to the first;

- a second end of the displacement member, opposite the support end, comprises a mortise or a tenon capable of cooperating with a corresponding tenon or mortise of the fitting tool, -

- the tapped hole is extended, opposite the jaws, by a co-axial orifice of larger diameter, defining an internal abutment shoulder of a corresponding shoulder of the fitting tool, produced in the vicinity of the post or the mortise of this installation tool;

- The removable fixing means of the support comprise first fixing means both in rotation and axially in a first direction, and second axial fixing means in the other direction;

- The first fixing means comprise an annular wall projecting from the body opposite the jaws, said wall defining tabs between which a first non-circular portion of the support can be received and which form a stop for another portion, larger diameter of said support, while the second fixing means comprise a thread formed on this wall annular, intended to receive a threaded section of said support;

- The implant comprises means for returning the second jaw to a position distant from the first jaw;

- The second jaw is removable from the body while the first jaw is made in one piece with the body;

- The second jaw is provided with a removable fixing cross member with respect to said body, cooperating with a transverse notch formed in said body in the vicinity of the first jaw.

The invention also relates to a delivery tool for the surgical implant as described above, characterized in that it comprises an operating member removable relative to this implant and suitable for actuating the means for moving the second jaw of this implant.

According to other characteristics of the invention:

- The operating member comprises a tenon or an end mortise adapted to cooperate with a mortise or a tenon which are provided with the means for moving the second jaw;

- The installation tool further comprises a tubular installation guide comprising removable fixing means on the implant, in particular by screwing, said installation guide being adapted to receive at least a sliding portion of said operating member.

The invention further relates to a marker support, intended to be attached to the implant as described above, characterized in that it comprises an elongated support body, means for detachably fixing said support body on said implant and removable fixing means of said marker on the support body.

According to other characteristics of the invention: the means for fixing the support body to the implant comprise first means for fixing the support body both in rotation and axially in a first direction, and second means for axial fixing in the other meaning ;

- The first fixing means comprise a first non-circular portion of said support body, suitable for being received between tongues with which the implant is provided, as well as another portion of the support body, extending said first portion and larger diameter, suitable for abutting against said tongues, while the second fixing means comprise a tubular member capable of sliding around said support body and comprising a removable fixing section on the implant, suitable for fitting said other portion of the body support, said tubular member also comprising a retaining section adapted to abut on said other portion of the support body. The invention finally relates to a surgical kit comprising an implant, a delivery tool and a marker support as described above.

The invention will be described below, with reference to the accompanying drawings, given only by way of nonlimiting examples and in which:

- Figure 1 is an exploded perspective view of a surgical implant, its delivery tool, and a marker support intended to be attached to this implant, forming a surgical kit according to the invention, - the Figure 2 is a longitudinal sectional view of the implant of Figure 1;

- Figure 3 is a view similar to Figure 2, of the implant receiving the delivery tool of Figure 1;

- Figure 4 is a view similar to Figure 2, illustrating an abutment position of the delivery tool relative to the implant; and

- Figure 5 is a view similar to Figure 2, of the implant receiving the support for markers of Figure 1-

The surgical kit according to the invention comprises, as shown in FIG. 1, an implant designated as a whole by the reference 2, a tool for placing this implant designated as a whole by the reference 4 and a support for marker , designated as a whole by the reference 6 and which is intended to be attached to the implant 2.

The implant 2 comprises a body 8, an upper part 10 of which is of semi-cylindrical shape and a lower part 11 of which comprises two side walls 12 parallel planes.

A first end of the body 8, which will be referred to in the following as the front end, is provided with a peripheral groove 14 extending both on the upper part 10 and on the side walls 12. The function of this groove will be explained in the following. The body 8 is extended, at its front end, by a first jaw 16 produced integrally from the lower part 11 of this body. This jaw 16 comprises a distal sole 18 provided with teeth 20. A transverse notch 22, the function of which will be explained below, is provided at the rear end of the body 8, at the level of the lower part thereof. This notch has a semi-circular bottom section.

The body 8 is extended, at its rear end, by a cylindrical wall 24, of common axis with the semi-cylindrical part 10 of the body 8.

The body 8 and this wall 24 are pierced with a through opening designated as a whole by the reference 26. As shown in particular in FIG. 2, this through opening comprises a tapped front portion 28, called in the following tapped hole, as well as a smooth portion or orifice 30, coaxial with the hole 28 and of larger diameter. The hole 28 and the orifice 30 define, at their connection zones, a peripheral shoulder 32. The annular wall 24 is provided, at its rear end, with an external thread 34 in which two symmetrical radial notches are formed by relative to the axis princi ^¬ pal of the wall 24, which thus define two threaded tabs 36. the implant 2 also includes a screw 38 to be screwed into the tapped hole 23. the latter has a front end 40 of rounded shape , and a rear end provided with a diametrical notch 42. The implant 2 further comprises a second jaw, generally designated by the reference 44, which comprises a sole 46 provided with teeth 48 and extended by two legs 50 forming longitudinal members, connected to each other by a cylindrical rod 52 forming a crosspiece. This rod is capable of being pivotally housed at the level of the semi-circular bottom of the notch 22 formed in the body 8. Since the width separating the legs 50 is greater than that of the sole 18, the second jaw 44 can be separated from the body 8 and the first jaw 16, which are made in one piece.

The sole 46 is provided, on its upper face opposite the teeth 48, with a chamfered rear portion 54 extending, when this second jaw 44 is as far as possible from the first jaw 16 (FIG. 3), almost perpendicular to the main axis of the through opening 26. In this position, the screw 38 is able to bear against this chamfered portion 54, so as to bring the second jaw 44 closer to the first jaw 16. Two notches 56, of semi-shaped circular, are formed in the legs 50, at the end of these adjacent to the sole 46. These notches 56 cooperate with the groove 14 formed in the body 8, in order to receive an elastic return ring 58 which tends to bring back the second jaw 44 in its position furthest from the first jaw 16, in which the chamfered portion 54 is located adjacent to the front end of the body 8.

The setting tool 4 of the implant 2 comprises an operating member 60 and a setting guide 62. The operating member 60 comprises a main cylindrical barrel 64 terminated, at its rear end, by a drive portion 66 intended to cooperate with a tightening key not shown. This barrel 64 ends, at its front end, with a tenon 68 of profile corresponding to that of the notch 42, forming a mortise, formed in the screw 38.

It should be noted that the diameter of the barrel 64, which is close to that of the orifice 30 is greater than the dimensions trans ^¬ main versales the tenon 68. A shoulder 70 is so formed at the connection zone between the barrel 64 and the post 68. As shown in particular in FIG. 4, this shoulder is intended to bear against the shoulder 32 of the body 8 of the implant 2. This makes it possible to limit the axial advance of the screw 38, and prevents the latter from detaching from the body 8, during its screwing.

The laying guide 62, which is annular, has a rear body 72, the internal diameter of which is slightly greater than that of the barrel 64, so that the operating member can slide freely inside this body 72. This the latter is extended by a front section 74 for fixing by screwing to the threaded wall 24 of the implant 2. This section has a tapped interior wall, the diameter of which is greater than the inside diameter of the barrel 64. The connection zone between this barrel 64 and this section 74 therefore defines a shoulder 76 intended to limit the axial movement towards the front of the assembly of the laying guide, when it is fixed to the threaded wall 24, by abutment against the rear end of the wall 24 The support 6 comprises an elongate support body 77 comprising a smooth rod 78 extended by a rear end 80 intended, in known manner, for the removable attachment of a marker not shown. The latter is associated with a locator and a computer, these three elements being for example in conformity with those belonging to the device marketed by the company NORTHERN DIGITAL under the reference OPTO-TRACK.

The rod 78 is terminated by a front end designated as a whole by the reference 82. The latter comprises a cylindrical rear portion 84, the diameter of which is close to that of the threaded wall 24, an intermediate cylindrical portion 86, of the same diameter as the portion 84 and truncated by two lateral flats 88, as well as a cylindrical front portion 90 whose diameter is less than that of the orifice 30 and on which the flats 88 extend. As can be seen in FIG. 5, this front portion is intended to enter this orifice 30, while the intermediate portion is intended to come to engage in the interior volume defined by the tongues 36 of the threaded wall 24, the rear portion 84 abutting against these tongues 36.

The support 6 also comprises an auxiliary screwing member designated as a whole by the reference 92, the structure of which is similar to that of the fitting guide 62 described above. This tubular screwing member 92 comprises a body 94 and a tapped front end 96 of larger diameter, these two elements defining, at their connection zone, a shoulder 98. The internal diameter of the body 94 is smaller on the one hand to the largest transverse dimension of the rear end 80 of the support 6, and on the other hand to the diameter of the front end 82. In this way, the screwing member 92 sees its movement limited axially in two opposite directions. On the other hand, the front section 96 has an internal diameter greater than that of the front end 82, so that this section 96 is able to fit the end 82, this movement being limited axially by the stop of the shoulder 98 against this end 82. The mounting of the implant 2 by means of the positioning tool 4, then the securing of the support 6 on this implant 2 will be explained with reference to all of the figures.

First place the screw 38 inside the tapped hole 28, so that it does not substantially protrude forward outside this tapped hole 28. Due to the presence of the elastic of return 58, the second jaw 44 is placed in the vicinity of this tapped hole 28 and is therefore in its position remote from the first jaw 16. The presence of the return elastic 58 also prevents any separation of this second jaw relative to the body

8, since this elastic contributes to directing the crosspiece 52 of this second jaw towards the bottom of its receiving notch 22.

The surgeon then screws (FIG. 3) the positioning guide 62 onto the implant 2, at the level of the threaded wall 24 of the latter. He then directs the implant 2 towards the bone part on which it must be fixed. This can be implemented easily, by gripping at the rear end of the installation guide. Then, the surgeon inserts the operating member 60 into the interior volume of this fitting guide, then engages the pin 68 of the member 60 inside the notch.

42, forming a mortise, of the screw 38. While holding the installation guide with one hand, the surgeon rotates, with the other hand, the operating member, so as to bring the rounded end 40 of the screw 38 in contact with the chamfered part 54 of the second jaw 44. This contributes to moving the latter in the direction of the first jaw 16. The axial advance of the operating member 60 relative to the through opening

26 is limited by the abutment of the shoulder 70 against

1 shoulder 32. The elastic has characteristics such that it does not substantially oppose such a displacement. When the jaws 16, 44 are sufficiently close together, in order to ensure a prior fixation of the implant

2 on the bone part considered, the surgeon consolidates this fixation by means of a tightening key not shown, cooperating with the drive portion 66 of the operating member 60. The fixing of the implant 2 on the bone part is then ensured by cooperation of the facing soles 18, 46 and their respective teeth 20, 48.

The surgeon then removes, by an axial movement, the operating member outside the interior volume of the positioning guide 62, then unscrews the latter from the threaded wall 24. Only the implant 2, whose overall dimensions are small, is then fixed on the bone part.

In a second step, the surgeon grabs hold (Figure 5) of the support 6, then directs the front end 82 towards the annular wall 24 of the implant. He then introduces the front portion 90 of the end 82 into the orifice 30, then the intermediate portion 86 of this end 82 into the interior volume of the tongues 36. The flats 88, inserted between the two tongues 36, prevent the support 6 from rotating relative to the implant 2, while the rear portion 84 limits the MOTION ^¬ axial support 6 to 1 'before 1 implant 2.

The surgeon then slides, along the rod 78, the screwing member 92 so as to screw it onto the wall threaded 24 of the implant 2. The shoulder 98 of this screwing member 92 prevents any axial movement of the marker 6 towards the rear of the implant 2. The support 6 then no longer has any degree of freedom relative to the implant 2. The surgeon finally fixes the marker, not shown, on the rear end 80 of this support 6, so as to access, in a known manner, the position and the orientation, relative to a reference bone element, from the bone part on which the implant 2 is placed. Once this position and this orientation have been determined, the support 6 of the implant 2 is removed, first unscrewing the member 92, then axially removing the end 82.

The surgeon then proceeds to the relative displacement of the bone piece provided with the implant and the reference element. Then, it again secures the support 6 on this implant 2, so as to establish a new position and a new orientation of the bone part thus displaced. In a later phase, the surgeon removes the support 6, then removes the implant 2 from the bone part on which it was fixed. To this end, it first screws the fitting guide 62 onto the implant 2, then moves the screw 38 backwards, by action of the operating member 60. This also contributes, thanks to the action elastic 58, to bring the second jaw 44 back into its position remote from the first jaw 16. The surgeon is then able to remove the implant 2.

The invention makes it possible to achieve the objectives mentioned above. Indeed, the implant, once fixed on the bone piece considered, is extremely compact, since its installation is ensured by means of a removable tool. In addition, the presence of the two jaws contributes to a reliable fixing of this implant on this bone piece. In this way, the positioning of the marker support on '1' implant is perfectly repeatable, in terms of position and orientation. Providing a tubular laying guide into which an actuator can be introduced is also advantageous. Indeed, this ensures an easy engagement of the operating member with respect to the displacement screw of the second jaw. In addition, this guide constitutes a safety element limiting the lateral movement of the operating member, in particular when the surgeon performs intense tightening. Finally, this positioning guide, given its axial dimensions, allows the surgeon to ascertain a priori whether the marker support, once put in place, will prove to be cumbersome during subsequent manipulations.

The use of means for returning the second jaw to a position remote from the first jaw is advantageous, since this ensures both an easy approach of the implant in the direction of the bone part, as well as a simple release. to implement this implant relative to this bone piece. In addition, the presence of these return means prevents any mutual separation of the two jaws.

The use of a removable jaw guarantees easy sterilization of the entire implant.

The use of removable fixing means of the support relative to the implant comprising on the one hand a fixing in rotation and in a first axial direction, and on the other hand, a fixing in the other axial direction, proves to be advantageous . Indeed, although this attachment of the support to the implant is carried out substantially without visibility by the surgeon, the latter can, in a simple manner, firstly engage the end of the support in the interior volume of the tongues. This allows the establishment of a prior positioning, then consolidated by sliding the screw member, then fixing the latter on the implant.

Claims

1. Surgical implant (2), intended to receive a marker, characterized in that it comprises a body (8), a first jaw (16) integral with said body, a second jaw (44) movable relative to said body and means for moving (38) said second jaw (44) from a position remote from the first jaw (16) to a position close to this first jaw (16), said moving means (38) being actuable by a installation tool (4) removable from said implant, said implant

(2) further comprising means (24, 36) for detachably fixing a support (6) of said marker.

2. Surgical implant according to claim 1, characterized in that the displacement means comprise a threaded member (38) cooperating with a threaded hole (28) formed in the body (8), said member (38) being adapted to come, by a first end (40), pressing against the second jaw (44) so as to bring it closer to the first (16).

3. A surgical implant according to claim 2, characterized in that a second end of the displacement member, opposite the support end (40), comprises a mortise (42) or a pin capable of cooperating with a tenon (68) or a corresponding mortise of the fitting tool (4).

4. A surgical implant according to claim 2 or 3, characterized in that the tapped hole (28) is extended, opposite the jaws (16, 44), by a coaxial orifice (30) of larger diameter, defining an internal shoulder (32) for abutting a corresponding shoulder (70) of the fitting tool (4), produced in the vicinity of the tenon (68) or of the mortise of this fitting tool.

5. Surgical implant according to any one of claims 1 to 4, characterized in that the removable fixing means of the support (6) comprise first fixing means both in rotation and axially in a first direction, and second axial fixing means in the other direction.

6. The surgical implant according to claim 5 characterized in that the first fastening means include an _¬ NENT an annular wall (24) projecting from the body ⁽⁸⁾ opposite the jaws ^(16, 44), said wall defining tongues (36) between which can be received a first non-circular portion (86) of the support (6) and which form a stop for another portion (84), of larger diameter, of said support, while the second fixing means comprise a thread formed on this annular wall (24), intended to receive a threaded section (96) of said support (6).

7. A surgical implant according to any one of claims 1 to 6, characterized in that it comprises return means (58) of the second jaw (44) in a position distant from the first jaw (16).

8. Surgical implant according to any one of claims 1 to 7, characterized in that the second jaw (44) is removable relative to the body (8) while the first jaw (16) is made in one piece with the body (8).

9. A surgical implant according to claim 8, characterized in that the second jaw (44) is provided with a crossmember (52) for removable fixing relative to said body (8), cooperating with a transverse notch (22) formed in said body (8) in the vicinity of the first jaw (16).

10. Installation tool for the surgical implant according to any one of the preceding claims, characterized in that it comprises an operating member (60) removable relative to said implant (2) and suitable for actuating the displacement means ( 38) of the second jaw (44) of said implant (2).

11. Installation tool according to claim 10, characterized in that said operating member (60) comprises a tenon (68 ⁾ or an end mortise adapted to cooperate with a mortise (42) or a tenon with which the means are provided movement (38) of the second jaw (44).

12. Installation tool according to one of claims 10 or 11, characterized in that it further comprises an installation guide (62) tubular comprising means (74) for removable attachment to the implant (2), in particular by screwing, said guide

(62) being capable of slidingly receiving at least a part of said operating member (60).

13. marker support intended to be attached to the implant according to any one of claims 1 to 9, characterized in that it comprises an elongated support body (77 ₎ , means (84, 86, 96) for removable fixing of said support body (77) on said implant (2) and means (80) for removable fixing of said marker on the support body

(77).

14. marker support according to claim 13, characterized in that the means for fixing the support body (77) on the implant (2) comprise first means (84, 86) for fixing the support body (77) both in rotation and axially in a first direction, and second means (96) for axial fixing in the other direction.

15. Marker support according to claim 14, characterized in that the first fixing means comprise a first non-circular portion (86) of said support body (77), suitable for being received between tongues (36) of which is provided with the implant (2), as well as another portion (84) of the support body (77), extending said first portion and of larger diameter, suitable for abutting against said tabs, while the second means of fixation comprise a tubular member (92) capable of sliding around said support body (77) and comprising a section (96) of removable attachment to the implant, suitable for fitting said other portion (84) of the support body, said member also having a tubular holding section (94) adapted to abut on said other portion (84) of the body of ^the support.

16. Surgical kit comprising an implant according to any one of claims 1 to 9, a delivery tool according to any one of claims 10 to 12 and a marker support according to any one of claims 13 to 15 .