WO2010026339A1

WO2010026339A1 - Osteosynthesis assembly, and surgical system used to perform osteosynthesis and comprising such an assembly

Info

Publication number: WO2010026339A1
Application number: PCT/FR2009/051657
Authority: WO
Inventors: Philippe Neyret; Olivier Rochetin
Original assignee: Verticale
Priority date: 2008-09-03
Filing date: 2009-09-02
Publication date: 2010-03-11
Also published as: FR2935255B1; FR2935255A1

Abstract

This assembly comprises an osteosynthesis body delimiting a through-opening for receiving an anchoring member that comprises a distal rod and a proximal head. The invention provides a set of mechanical locking nuts. Each nut of this set delimits, on the one hand, an outer lateral surface which is cylindrical and threaded and an internally threaded, frustoconical through-hole. At least two nuts in the set are respectively associated with different values of angulation, one of which is optionally zero, for the angle formed between the central axis of their hole and the central axis of their outer lateral surface.

Description

OSTEOSYNTHESIS ASSEMBLY AND SURGICAL SYSTEM FOR

PRACTICE OSTEOSYNTHESIS COMPRISING SUCH A SET

The present invention relates to an osteosynthesis assembly, as well as a surgical system for performing osteosynthesis comprising this assembly.

The invention thus aims to provide the surgeon with means to strengthen an altered bone site, in particular fractured, even fragmented, or severed, due to trauma or pathology. This is for example the case in the context of a tibial or femoral osteotomy, followed by the establishment of a wedge of valgization or varization, or in the context of a reduction of fracture, accompanied by the setting in place of an osteosynthesis plate.

More specifically, the invention relates to osteosynthesis bodies, whether they be plates, wedges or any other similar element, which are attached to a bone by bone anchoring screws or similar elongated organs: for this purpose, the The stem of these screws is threaded through an orifice passing through the body from one side to the other until the head of the screws is mechanically linked to the wall of the orifice, so as to then press the distal face of the body against the bone.

In order to prevent the screw from being able to disengage from the body of osteosynthesis in the long run, in particular under the action of bone stresses related to the movements or to the pathology of the patient, it is well known to try to block the head of the screw in the orifice. To this end, many blocking systems have been proposed so far. We can cite the systems including a counter-screw, which is screwed into a proximal threaded portion of the orifice after installation of the anchor screw, or the systems including a split olive, whose freedom of movement in the orifice is neutralized by jamming when the screw head is received inside the olive.

All existing systems have the disadvantage of being complicated to set up by the surgeon. In addition, their reliability and mechanical strength are generally mediocre as soon as these systems include the possibility of choosing the direction of introduction of the screw into the orifice of the body: the advantage of choosing this direction of implantation is real because, rather than being forced to place the screw coaxially at the orifice, the surgeon can thus implant the screw into a Specific bone area more or less distant from the central axis of the orifice, for example a healthier or more fragmented area.

Thus, WO-A-2006/102110 proposed to interpose, between the through hole of an osteosynthesis plate and a bone anchoring screw, an adapter. This adapter delimits internally a through hole for receiving and screwing the frustoconical threaded head of the anchor screw. Externally, the adapter is provided to lock in the through hole, several embodiments for this locking being mentioned. Furthermore, WO-A-2006/102110 provides for tilting the direction of implantation of the anchor screw relative to the central axis of the hole of the plate: in this case, under the action of screwing of the head of the anchor screw inside the adapter, the outer face of this adapter is permanently deformed in the hole of the plate, locking the angular position of the adapter in a non-adjustable manner . The establishment of this set of osteosynthesis is difficult to obtain a satisfactory accuracy.

The object of the present invention is to provide a set of osteosynthesis, the reliability of bone fixation is improved regardless of the implantation direction of the anchor screw, while being easy to set up by the surgeon. For this purpose, the subject of the invention is an assembly of osteosynthesis, as defined in claim 1.

The basic idea of the invention is, for each anchoring member to be locked relative to the body after having inserted its rod into one of the orifices of this body, to provide the surgeon with a set of several locking nuts. of the head of this organ in the orifice. These different nuts all have the same geometry with respect to their external lateral surface, namely a cylinder provided with a thread in order to be able to screw each of the nuts in the orifice, which is provided in a complementary manner. On the other hand, the various nuts of the game have respective specific internal geomethes, namely frustoconical holes of the same conicity, which are provided with the same tapping, but whose respective values of the angle formed between their central axis and the central axis of the cylindrical outer lateral surface of the nut, are specific to each of the nuts. In practice, these angulation values specific to each nut of the game They are, for example, respectively equal to 2 ° 4 ° 6 ° 8 ° and 10 °, and possibly 0 °, which amounts to saying that one of the nuts of the game has its tapered tapped hole which is centered on the central axis of its cylindrical outer side surface. The head of the anchoring member has a threaded frustoconical lateral surface, which is complementary to the respective holes of the nuts so that, when this head is screwed inside one of these holes, it tends to radially deform towards outside the wall of the nut, considering the cooperation of the truncated cone that forms the head and the truncated cone that forms the hole internally. This deformation is transmitted to the outer lateral surface of the nut which, having been previously screwed into the complementary orifice of the body, is then firmly stuck in this orifice in the sense that the nut is impossible to to be unscrewed or to disengage due to the biasing of its external thread, which is somehow, seized in the tapping of the orifice. It is understood that the choice, by the surgeon, of the nut to be screwed into the orifice is related to the angulation of the desired direction for implanting the anchoring member: according to whether the surgeon wishes to implant this organ at an angle from 0 ° 2 ° 4 ° 6 ° 8 ° or 10 ° for example, in relation to the central axis of the orifice, he chooses the nut whose angulation value corresponds. Then, depending on the bone region in which the anchoring member must be introduced under the selected angulation, that is to say according to the angular position of this bone region following the periphery of the orifice, the surgeon sets the angular position of the selected nut in the orifice, by adjusting the screwing depth of the nut in the orifice. The introduction of the anchoring member through the nut, until the screwing of its head into the hole of the nut, is then performed along the central axis of the hole, in other words in the direction initially desired. Thus, by simple and rapid gestures, the surgeon reliably secures the anchoring member to the osteosynthesis body, while having implanted the anchoring member in the direction that it has previously chosen. Advantageous features of the osteosynthesis assembly according to the invention, taken individually or in any technically possible combination, are specified in the dependent claims 2 to 7. The invention also relates to a surgical system for performing osteosynthesis, as defined in claim 8.

Thanks to the surgical system according to the invention, the surgeon has at his disposal, for example, a set of as many ancillaries as nuts belonging to the set of nuts of the set of osteosynthesis: once the surgeon has chosen the direction of implantation of the anchoring device to be placed in a bone, he uses, among the set of nuts and the set of ancillaries at his disposal, the associated nut and ancillary one to the other, whose angulation value corresponds to that of the implantation direction, to successively set up the pin and the anchor member. Another possible case is that the surgeon has the opportunity to adjust the implantation direction defined by the ancillary and thus match its angulation value with that of the chosen nut, so that this ancillary adjustable is usable for several nuts of the game.

Advantageous features of the surgical system according to the invention are specified in the dependent claims 9 and 10.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings in which:

- Figure 1 is a perspective view of an osteosynthesis assembly according to the invention;

FIG. 2 is an elevational view of the assembly of FIG. 1, seen along the arrow II of FIG. 1 and implanted to a bone;

- Figure 3 is a section along the line III-III of Figure 2;

- Figure 4 is an elevational view along the arrow IV of Figure 1; - Figures 5 and 6 are exploded in perspective of a portion of the set of Figures 1 to 4, respectively at opposite angles of view;

FIG. 7 is a perspective view of an ancillary device used to implant the osteosynthesis assembly of FIGS. 1 to 4;

- Figure 8 is a section along the plane VIII of Figure 7, illustrating the use of the ancillary on part of the set of osteosynthesis shown in the sectional plane of Figure 3; and

- Figure 9 is a view similar to Figure 7, illustrating a variant of the ancillary. FIGS. 1 to 6 show an osteosynthesis assembly 2 intended to reinforce an altered part of a bone 1 represented solely in FIGS. 2 and 3, in particular for traumatic or pathological reasons. This assembly 2 comprises an osteosynthesis body 10 fixed to bone 1 by other components of the assembly, as described in detail below. In practice, the body 10 may as well be an osteosynthesis plate, used in the treatment of reduction of a fracture of a bone, a wedge of valgization or varization used in the correction treatment of a genu varum or genu valgum by tibial or femoral osteotomy. Thus, according to the surgical nature of the osteosynthesis body 10, the latter has various shapes and dimensions, not limiting of the invention envisaged here. In particular, the lines of its outline drawn on the figures have no technical reality.

For convenience, the description of the assembly 2 is oriented relative to the bone 1, in the sense that the terms "proximal" and "distal" designate turned directions, respectively, opposite the bone and to this bone, which corresponds in particular to the point of view of the surgeon who sets up the assembly 2 on the bone 1. Thus, the body 10 has, at least as regards its part considered in the figures, a distal surface 10A plated against bone 1 and an opposite proximal surface 10B. The body 10 delimits through orifices, which each connect the distal 10A and proximal 10B surfaces to each other. In the embodiment considered here, these through holes are identical to each other and are three in number, being respectively referenced 11 i, 112 and II 3, as clearly visible in Figures 5 and 6. Each orifice 11 i 11 ₂ and 11 ₃ is cylindrical with a circular base, centered on an axis X1-X1, X2-X2, X3-X3- Here, the X1-X1 axis, X2-X2 and X ₃ -X ₃ are parallel to each to others. Of course, in a variant not shown, these axes may not be parallel, according to the shape of the bone 1 and therefore the body 10. The axial dimension of each orifice corresponds to the thickness of the portion of the osteosynthesis body 10 traversed by this orifice, this thickness here being identical for the three orifices and noted E in FIG.

Each orifice H ₁ , 11 ₂ , 11 ₃ is threaded over its entire axial dimension, the corresponding thread of tapping being referenced 12, 12 ₂ , 12 ₃ . On its proximal surface 10B, the body 10 is provided, around the outlet of each orifice H ₁ , 11 ₂ and 11 ₃ , of a series 13i, 13 ₂ , 13 ₃ of angular graduations centered on the axis X1-X1, X2-X2, X3-X3, as clearly visible in Figures 2 and 6. In the example considered here, two successive graduations of each series are spaced 5 °.

The osteosynthesis assembly 2 also comprises bone anchoring screws, here also three in number and respectively referenced 20i, 2O2 and 2O3. Each screw 20i, 2O2 and 2O3 extends in length around a central axis Y ₁ -Y _1, Y ₂ -Y _2, Y ₃ -Y ₃ - Each screw comprises a threaded rod 2I ₁ , 21 ₂ , 21 ₃ , able to be screwed into the bone 1, and at the proximal end of this rod, an enlarged head 22 _1; 22 ₂ , 22 ₃ . The rod and the head of each screw 20i, 2O ₂ and 2O ₃ are dimensioned so as, on the one hand, that the rod 2I ₁ , 21 ₂ , 21 ₃ can be fully threaded through the orifice H ₁ , 11 ₂ , 113 and, secondly, that the head 22i, 22 ₂ , 22 ₃ can be housed, preferably completely, inside the hole H ₁ , 11 ₂ , 11 ₃ with interposition of a nut 3O ₁ , 3O ₂ , 3O ₃ , which will be described in detail later and which mechanically links the head and the orifice to lock the screw relative to the osteosynthesis body 10 after having introduced the rod through this hole beforehand equipped with the nut. In the absence of the nuts 3O ₁ , 3O ₂ and 3O ₃ , it will be noted that each of the screws 2O ₁ , 2O ₂ and 2O ₃ can be received in the corresponding hole H ₁ , 11 ₂ , 11 ₃ so that the axes Y ₁ -Y ₁ , Y ₂ -Y ₂ and Y ₃ -Y ₃ are respectively identical with the axes X ₁ -X ₁ , X ₂ -X ₂ and X ₃ -X ₃ , as for the screw ₂ O ₂ in the exemplary embodiment considered in the figures, or so that the axis Y _1- Y _1, Y ₂ -Y _2, Y ₃ -Y ₃ extend obliquely relative to the axis X ₁ -X ₁ , X ₂ -X ₂ and X ₃ -X ₃ , as is the case for the screws 2O ₁ and 2O ₃ . In practice, the surgeon decides in advance the inclination of the axis of each screw, that is to say its angulation, possibly zero, relative to the axis of the orifice and its position angularly around the axis of the orifice, so that the screw is anchored in a bone region deliberately targeted by the surgeon.

The head 22, 22 ₂ , 22 ₃ of each screw 2O ₁ , 2O ₂ , 2O ₃ is provided with a frustoconical outer side surface 22A ₁ , 22A ₂ , 22A ₃ , centered on the axis Y _{1 -} Y ₁ , Y ₂ -Y ₂ , Y ₃ -Y ₃ and convergent towards the rod 2I ₁ , 21 ₂ , 21 ₃ . Each of these frustoconical surfaces is threaded, as clearly visible for the surface 22A ₁ in FIG. To enable the rotation of each rod 21 ₁ , 21 ₂ , 21 ₃ around its axis Y ₁ -Y ₁ , Y ₂ -Y ₂ , Y ₃ -Y ₃ , the proximal side of the head 22i, 22 ₂ , 22 ₃ delimits a hollow cavity 23i, 23 ₂ , 23 ₃ , as clearly visible for the head 22i in FIG. 6. In a manner known per se, the aforementioned cavity is intended to cooperate by complementarity of shapes with the distal end of a tool not shown, which is introduced into the imprint.

For reasons specified below, related to the guiding of the screws 20i, 2O ₂ and 2O ₃ during their implantation in the bone 1, the head 22 _1; 22 ₂ , 22 ₃ and the rod 211, 21 ₂ , 213 of each of these screws are traversed right through by a bore 24 _1; 24 ₂ , 24 ₃ centered on the axis Y1Υ1, Y ₂ -Y ₂ , Y3-Y3, as clearly visible in FIG.

Each nut 30i, 3O ₂ , 3O ₃ , has a tubular structure, whose outer lateral surface 30Ai, 30A ₂ , 30A ₃ is cylindrical with a circular base, centered on an axis Zi-Zi, Z ₂ -Z ₂ , Z ₃ - Z ₃ . These cylindrical surfaces 30Ai, 30A ₂ and 30A ₃ are geometrically identical to each other and are thus respectively provided with a thread thread 31 ₁ , 31 ₂ and 31 ₃ complementary to the tapping thread 12i, 12 ₂ , 12 ₃ orifices 11 i, 11 ₂ and 11 ₃ . Thus, as shown in FIGS. 1 to 4, the nuts 30 1, 30 ₂ and 30 ₃ can be respectively screwed into the orifices 11 ₁ , 11 ₂ and 11 ₃ of the osteosynthesis body 10.

Advantageously, the dimension of each nut 30i, 3O ₂ , 3O ₃ along the axis Zi-Z ₁ , Z ₂ -Z ₂ , Z ₃ -Z ₃ , in other words the thickness of this nut denoted e in FIG. strictly less than the thickness E of the body 10, the difference between these two thicknesses corresponding to at least one pitch of the tapping thread 12i, 12 ₂ , 12 ₃ . In this way, when the nut is screwed into the corresponding orifice, it can be housed entirely in this orifice and its angular position inside this orifice can be adjusted 360 ° about the X axis 1- X1, X ₂ -X ₂ , X ₃ -X ₃ , without the axial ends of the nut protruding from the outlets of the orifice on the surfaces 10A and 10B of the body 10.

In practice, the difference in the thicknesses e and E may take a small value by choosing a fine pitch for the thread threads 311, 31 ₂ , 31 ₃ and tapping threads 12 ₁ , 12 ₂ , 13 ₃ .

On their proximal end face 30Bi, 30B ₂ , 30B ₃ , each nut 30 ₁ , 30 ₂ , 30 ₃ is provided with a relief 32 ₁ , 32 ₂ , 32 ₃ , here in the form of a pair of two diametrically opposite blind cavities. with respect to the Zi-Zi axis, Z ₂ -Z ₂ , Z ₃ -Z ₃ . This relief is intended to cooperate by complementary shapes with the distal end of a specific ancillary, which will be presented later with reference to Figures 7 and 8.

Furthermore, each nut 30i, 3O _2, 3O ₃ delimits, inside the tubular structure, a frustoconical hole 30Ci, 30C _2, 30C _3, centered on an axis W ₁ W _1, W ₂ -W _2, W ₃ -W ₃ and diverge towards the proximal end surface 30B ₁ , 30B ₂ , 30B ₃ of the nut. As is clearly visible in Figure 3, the axes W ₁ W _1, W ₂ and W ₃ -W ₂ -W ₃ are positioned differently vis-à-vis the axis Z ₁ Z _1, Z ₂ - Z ₂ , Z ₃ -Z ₃ of the lateral surface 30A ₁ , 30A ₂ , 30A ₃ of their nut: the axes W ₁ -W ₁ and Z ₁ -Z ₁ belong to the sectional plane of FIG.

3 and form between them an angle O ₁ ;

the axes W ₂ -W ₂ and Z ₂ -Z ₂ coincide, which amounts to saying that they form between them an angle α ₂ of zero value; and

the axes W ₃ -W ₃ and Z ₃ -Z ₃ belong to a plane perpendicular to the plane of section of FIG. 3 and, as clearly visible in FIG. 4, form an angle α ₃ between them.

It will be noted that, in the exemplary embodiment considered here, the angles O ₁ and α ₃ have the same angular value, namely 8 °. Consequently, it is understood that the nuts 3O ₁ and 3O ₃ are identical to each other but that, in their configuration screwed into their corresponding hole H ₁ , 11 ₃ , these two nuts occupy angular positions, respectively around of the axis X ₁ -X ₁ and the axis X ₃ -X ₃ , different from each other, namely shifted by a quarter of a turn relative to each other.

To identify the angular position, respectively about the axis X ₁ -X ₁ and the axis X ₃ -X _3, axes W _1- W ₁ and W ₃ -W ₃ when the nuts ₁ and 3O 3O ₃ are screwed into the corresponding hole H ₁ , 11 ₃ , the proximal end surface 30B ₁ , 30B ₃ of each of these nuts is provided with a reference pattern 33 ^ 33 ₃ , here in the form of a triangle, by which passes the plane containing the axes respectively ₁ W W ₁ and Z ₁ Z ₁ and W ₃ -W axes ₃ and Z ₃ -Z _3. Advantageously, as shown here, this pattern mark 33 ^ 33 ₃ is located on the side of the axis Z ₁ Z _1, Z ₃ -Z ₃ in which extends the axis W ₁ W _1, W ₃ -W ₃ on the distal side of the nut 3O ₁ , 3O ₃ . Of course, the nut 3O ₂ , whose angle α ₂ is zero, is devoid of such a reference relief, since unnecessary. Each frustoconical hole 30Ci, 30C ₂ , 30C ₃ is threaded over its entire axial dimension, the corresponding thread of tapping being referenced 35i, 35 ₂ , 35 ₃ . This thread tapping 35i, 35 ₂ , 35 ₃ is complementary to the thread thread of the lateral surface 22Ai, 22A ₂ , 22A ₃ of the screw head 22i, 22 ₂ , 22 ₃ and, at the same time, the taper of the truncated cone forming the hole 30Ci, 30C ₂ , 30C ₃ is adjusted to that of the truncated cone delimiting this lateral surface, so that the screw head 22i, 22 ₂ , 22 ₃ can be screwed in a complementary manner in the hole 30Ci , 30C ₂ , 30C ₃ of the corresponding nut 30i, 3O ₂ , 3O ₃ , until substantially completely housed the screw head inside the nut, as shown in Figures 1 to 4.

In addition, the tubular structure of each nut 30i, 3O ₂ , 3O ₃ has a certain elasticity, allowing it to be deformed radially to the axis W ₁ -W ₁ , W ₂ -W ₂ , W ₃ -W ₃ , especially towards the outside. For this purpose, the nuts are advantageously made of titanium or alloy based on titanium. Also for this purpose, in the embodiment considered here, each nut is provided with four slots passing radially right through the tubular wall of the nut. These four slots are identical for each of the nuts 3O ₁ , 3O ₂ , 3O ₃ so that, for reasons of visibility and clarity in the figures, only the slots of the nut 3O ₁ are described below in detail, by being respectively referenced 3G ₁ 1, 3G ₁ 2, 3G _{1 3} and 3G _{1 4} in the figures. As clearly visible in FIGS. 5 and 6, the four slots 3G ₁ 1, 3G _{1 2} , 3G _{1 3} and 3G _{1 4} are regularly distributed around the axis Z _{1 -} Z ₁ . Each of these slots has an L-shaped profile when the nut 3O _{1 is} observed in a direction radial to the axis Z ₁ -Z ₁ : in other words, each of these slots includes a first elongated part, which extends in parallel. to the axis Z ₁ Z _1, since one of the proximal end faces 30B and distal 30D ₁ ₁ of the nut 3O ₁ and to an intermediate area of the nut at which the first part is extended following the circumferential direction of the nut by a second elongated portion. Figures 5 and 6, the said first and second parts of the 3G slot ₁ are referenced respectively 37 _Ï _{Ï Ï} 3S and ₁ 1. Note that the first part of two successive slits among the slits 3G ₁ - _\ 3G _{1 4} do not open on the same front surface 30B ₁ or 30D ₁ of the nut 3O ₁ . On the contrary, these first two parts open respectively to one of these front surfaces. This alternation of slots 36i 1 to 36i ₄ with regard to the front surfaces 30Bi and 30Di of the nut 30i from which one or the other of which the first part of each slot extends, combined with the fact that these four slots are regularly distributed following the periphery of the nut, promotes the homogenization of the radial deformation of the following nut, both its axial direction and its peripheral direction.

The establishment of the osteosynthesis assembly 2 on the bone 1 is as follows.

At first, the surgeon positions the osteosynthesis body

10 against the bone 1. It then screws each of the nuts 30i, 3O ₂ , 3O ₃ in the corresponding orifices 11 ₁ , 11 ₂ and 11 ₃ of this body 10. To do this, the surgeon advantageously uses a specific ancillary of a set of ancillaries at its disposal, one of these ancillaries being shown in Figures 7 and 8 being designated as reference 40. In practice, the choice by the surgeon of the ancillary among those at its disposal is a function of the angulation with which the surgeon wishes to implant each of the screws 20i, 2O ₂ and 2O ₃ . Indeed, as explained above, according to the particular condition of the bone material of the bone 1, the surgeon decides whether it is desirable to incline each screw 2O _1, 2O ₂ 2O ₃ with respect to the axis X ₁ - X _1, X ₂ -X _2, X ₃ -X ₃ H of the corresponding hole ₁ 11 ₂ 11 _3. For example, it is considered here that the surgeon decides to install, on the one hand, the screws 2O ₁ and 2O ₃ with an angulation of 8 ° and, on the other hand, the screw 2O ₂ with an angulation nothing. Under these conditions, the surgeon selects, at the same time, the identical nuts 3O ₁ and 3O ₃ , the value of the angles O ₁ and α ₃ is 8 ° and the ancillary 40 whose angle β is also 8 ° this angle β being formed between, on the one hand, the central geometric axis 41 of its distally cylindrical outer circular end 42 and, on the other hand, the central geometric axis 43 of a bore 44 passing right through, both, its distal end 42 and its proximal handle 45. The surgeon uses this ancillary 40 to screw the nut 30 ₁ in the corresponding hole 1 I ₁ .

For this purpose, the distal end 42 of the ancillary 40 has a distal end surface 42A, perpendicular to the axis 41 and provided with two projecting studs 46, complementary to the two blind cavities of the relief 32 _! of the nut 30 ₁ : when the pins 46 are received in the relief 32i, the axes 41 and Z ₁ -Z ₁ coincide and the axes 43 and W ₁ -W ₁ coincide, as shown in FIG. causing the ancillary 40 to rotate about its axis 41, in particular with the aid of a handle 47 with which the handle 45 is equipped, the surgeon screws the nut

3Oi in the hole 111, until fully accommodate this nut in this hole.

Still using the ancillary 40, the surgeon then accurately sets the angular position around the axis X1-X1 of the nut 30i. To do this, the distal end 42 of the ancillary 40 is provided, at a point of its outer periphery, with a notch 48. This notch is positioned relative to the nubs 46, so as to occupy the same angular position around the axis 41, the reference pattern 33i about the axis Z1-Z1 when the pins 46 are received in the recesses of the relief 32i. In this way, by adjusting the angular position of the notch 48 about the axis X1-X1, the surgeon adjusts correspondingly the angular position of the fiducial pattern 33i about that axis. In practice, this angular adjustment is at the discretion of the surgeon, in the sense that, depending on the chosen setting, the coinciding axes 43 and Wi-Wi will extend in a specific region of the bone 1. Advantageously, the surgeon for this purpose of the notch 48, by reading the graduation among the series 13i opposite this notch: this information allows it to quantify the angular position of the distal end 42 relative to the osteosynthesis body 10 and thus by to bone 1 in the event that the position of this body is fixed or, at least, reliably identified by adequate means, not detailed here.

It will be understood that the surgeon has the possibility of effecting this angular adjustment over 360 ° about the axis X 1-X 1, while keeping the whole of the nut 30i inside the orifice 11 i, because the difference of the thicknesses E and e, as explained above. Once this angular adjustment is achieved, the surgeon uses a spindle 50 whose cross section is adjusted to the cross section of the bore 44: it gradually introduces this spindle through successively the bore 44, the hole 30Ci of the nut 30i and bone 1, as indicated by the arrow F ₅ o in Figure 8. This pin 50 is thus implanted along the axes 43 and Wi-Wi. Therefore, this pin 50 forms with the X axis _r Xi an angle of 8 ° and is positioned angularly around this axis X ₁ -X ₁ , extending through the region of the bone 1 targeted by the surgeon. The ancillary 40 is then released, if necessary by first removing and then replacing the pin 50 in the bone 1. In practice, the pin 50 can be held in place during the release of the ancillary, because the fact that the cooperation games between manipulated elements are sufficient to disengage the relief cavities 32 _Ï studs 46 when the ancillary device is moved away in the direction of the coincident axes 43 Bt W ₁ -W _1. Then the surgeon then places the screw 2O _1, with the help of the pin 50: 24 bore! has indeed an inner section fitted on the cross section of the spindle 50 so that the screw can be threaded around the spindle and thus guided by the latter when the screw is gradually screwed into the bone 1 along the axis W _{1 -} W ₁ .

By thus continuing the screwing of the screw 2O ₁ , its head 22 _! is introduced into the hole 30C ₁ and is screwed into this hole, by engagement of the tapping thread

35 ^. Advantageously, to ensure immediate engagement between the tapping thread 3S ₁ and the thread thread of the surface 22A ₁ of the head 22! , the net 35i is double entries.

This screwing of the head 22i radially constrains the nut 30i, due to the frustoconical interface between the lateral surface 22A ₁ of the head and the hole 30C ₁ . A radial stress, directed outwards, is then exerted along the entire periphery of the nut 3O ₁ , which deforms the tubular wall of the nut radially outwardly. Its lateral surface 22A ₁ , which hitherto was in screwing / unscrewing engagement with the tapping thread 12i of the orifice H ₁ , is correspondingly deformed, which impinges this surface in the tapping thread 12i and prevents and any subsequent screwing or unscrewing movement within the hole H _1. In other words, the nut 3O ₁ is firmly locked within the orifice 11 _1, thereby immobilizes the screw 2O ₁ relative to the body bone 10, as shown in Figures 1 to 4.

The implantation of the osteosynthesis assembly 2, with regard to the screw 20 ₁ , is then finalized by removing the pin 50.

We just described above the establishment of the nut 3O ₁ and the screw 2O ₁ . It is understood that the establishment of the nut 3O ₃ and the screw 2O _{3 is} carried out in the same way, being recalled that the nuts 3O ₁ and 3O ₃ are identical, with the difference that the same ancillary 40 is used to angularly position the nut 3O ₃ inside its corresponding orifice 11 ₃ in a different way than the nut 30i in its orifice 11 i, as is clear from FIG. 2, by observing the different respective angular positions of the reference pattern 33i and the reference pattern 33 ₃ .

The establishment of the nut 3O ₂ and the screw 2O _{2 is} performed analogously, with the difference that the surgeon uses another ancillary instrument than the ancillary 40, namely an ancillary functionally similar to the ancillary 40 but whose angle β is zero.

More generally, it follows from the above that, according to the invention, the surgeon has at his disposal, for fixing the osteosynthesis body 10 to the bone 1, a set of several nuts, such as the nuts 30i. , 3O ₂ and 3O3, and a set of corresponding ancillaries, such as ancillary 40. The aforementioned set of nuts includes nuts identical to each other, except for the value of the inclination of the central axis of their frustoconical hole relative to the central axis of their cylindrical outer lateral surface, as is the case for the values of the angles O ₁ and α ₃ associated with the nuts 3O 1 and ₃ O ₃ and the angulation value zero for the nut 3O ₂ . Typically, the angulation values associated with the various nuts of the aforementioned set are respectively equal to 0, 2 ° 4 ° 6 ° 8 ° and 10 °, it being understood that several ecs of the same angulation value can be provided in the play, as is the case for the nuts 3Oi and 3O ₃ .

The abovementioned set of ancillaries comprises, for its part, as many ancillaries as different angulation values for the nuts of the set of nuts, these different ancillaries having an angle β whose respective values are equal to the different values of angulation. . FIG. 9 shows a variant of the ancillary 40, referenced

40. The ancillary 40 'is less elaborate than the ancillary 40, in the sense that its distal end 42' is not arranged to allow to drive in rotation the nuts 3Oi and 3O ₃ . Instead, this distal end 42 'is shaped into a smooth cylinder substantially complementary to the orifices 11 i and 11 ₃ . This cylinder can thus be housed coaxially in each of these orifices so that, in this configuration, the spindle 50 is progressively introduced into a bore 44 'identical to the bore 44 of the ancillary 40, until it enters the 1. Before clearing the 40 'ancillary, the surgeon links, opposite a notch 48' identical at the notch 48 of the ancillary 40, the graduation representative of the angular position of the implantation direction of the pin 50 about the axis X1-X1 or X ₃ -X ₃ , among the series of graduations 13i or 13 ₃ . After clearance of the ancillary 40 ', the surgeon screws the nuts 3Oi and 3O ₃ , whose CM angulation value, α ₃ is equal to the angle β' of the ancillary 40 ', in the orifices 11 ₁ and 11 ₃ and, while these nuts are housed entirely in the corresponding orifices, it angularly positions each of these nuts adequately, by aligning their reference pattern 33i, 33 ₃ on the scale read previously with the help of the notch 48 '. The pin 50 is then put back into place in the bone, through the hole 30Ci, 30C ₃ of the nut, to guide the implantation of the screws 2Oi and 2O ₃ , in the same way as described above.

Various arrangements and variants to the set of osteosynthesis 2 and ancillaries 40 and 40 'described above are also possible. Examples: - rods 21 ^ 21 ₂ and 21 ₃ of the screw 2Oi, 2O 2O ₂ and ₃ may have threads of various shapes and dimensions, depending on the nature of the bone 1 wherein these screws must s anchor; likewise, one or more of these screws may be replaced by pins, in the sense that their rods 2I ₁ , 21 ₂ , 21 ₃ then have a smooth outer surface; - The use of pins 50 to guide the implantation of the screws 20i, 2O ₂ and 2O ₃ is optional, these screws then no longer having a central bore 24i, 24 ₂ , 24 ₃ ; in this case, after having chosen, from the set of nuts at its disposal, the nut whose angulation value is satisfactory for its needs, the surgeon screws this nut into the corresponding orifice of the osteosynthesis body 10 and once this nut is completely housed in the orifice, it adjusts its angular position so that the central axis of the frustoconical hole inside the nut is aimed at a region of the bone 1 that it has chosen, particularly in using the reference pattern of the nut and the series of graduations surrounding the proximal opening of the orifice; the surgeon then introduces the screw through the nut and screws it gradually into the bone taking the precaution of centering this screw on the central axis of the frustoconical hole of the nut; and or

- rather than providing as many "frozen" 40 or 40 'ancillaries as nuts, only one ancillary can be used by the surgeon if the inclination of the distal end of this ancillary is adjustable, relative to its handle, by the surgeon according to the inclination he has chosen to implant the anchor screw.

Claims

1. Set of osteosynthesis (2), comprising:

a bone anchoring member (20 ₁ , 20 ₂ , 20 ₃ ) which comprises a distal rod (211, 21 ₂ , 21 ₃ ) adapted to anchor deep into a bone (1), and a proximal head (22). _! 22 ₂ 22 ₃₎ adapted to be driven in rotation on itself about the longitudinal axis (Y1-Y1, Y ₂ -Y _2, Y ₃ -Y ₃₎ of the rod,

an osteosynthesis body (10), which delimits a through orifice (1 I ₁ , 112, 113) for receiving the anchoring member, and

- means (30i, 3O ₂ , 3O ₃ ) connecting the head and the orifice to lock the anchoring member relative to the osteosynthesis body after having introduced the rod through the orifice, characterized in that that the connecting means comprise a set of mechanical locking nuts (30i, 3O ₂ , 3O ₃ ), each nut delimits, on the one hand, a cylindrical threaded outer lateral surface (30Ai, 30A ₂ , 30A ₃ ), which is substantially complementary to a female thread of the orifice (1 I ₁ 11 ₂ 11 ₃₎ to screw the nut around the central axis (Z1-Z1, Z ₂ -Z _2, Z ₃ -Z ₃ ) of this outer lateral surface, in an adjustable angular position relative to the osteosynthesis body (10), and, on the other hand, a tapered frustoconical through hole (30Ci, 30C ₂ , 30C ₃ ), which is substantially complementary an outer lateral surface (22Ai, 22A ₂ , 22A ₃ ) of the head (22 _1; 22 ₂ , 22 ₃ ), both frustoconical convergent toward the rod (211, 21 ₂ , 21 ₃ ) and threaded to screw this head into the hole and thus deform radially outwardly the outer lateral surface of the nut, at least two nuts of the game being respectively associated with different eigenvalue values, of which the is a possibly null for the angle (ai, α _2, α ₃₎ between the central axis (Wi-Wi, W ₂ W _2, W ₃ -W ₃₎ from their holes and the central axis ( zi-zi, Z ₂ -Z _2, Z ₃ -Z ₃₎ of their outer lateral surface.

2. An assembly according to claim 1, characterized in that each nut (30i, 3O ₂ , 3O ₃ ) of the game has, along the central axis (Zi-Zi, Z ₂ -Z ₂ , Z ₃ -Z ₃ ) of its outer lateral surface (30Ai, 30A ₂ , 30A ₃ ), a dimension (e) strictly less than the axial dimension (E) of the orifice (1 I ₁ , 11 ₂ , 11 ₃ ).

3. An assembly according to claim 2, characterized in that the difference in the respective axial dimensions (e, E) of each nut (30i, 3O ₂ , 3O ₃ ) and the orifice (11 i, 11 ₂ , 113) is greater than the pitch of the complementary threads (311, 31 ₂ ,

31 _3> 12i, 12 _2> 12 ₃ ) of the nut and the hole.

4. An assembly according to any one of the preceding claims, characterized in that each nut (30i, 3O ₂ , 3O ₃ ) of the game is provided on its front surface (30B ₁ ) on which opens the diverging side of the hole (30Ci , 30C ₂ , 30C ₃ ), a relief (32 ^ 32 ₂ , 32 ₃ ) for rotating the nut about itself about the central axis (Zi-Zi, Z ₂ -Z ₂ , Z ₃ -Z ₃ ) of its outer lateral surface (30Ai, 30A ₂ , 30A ₃ ).

5. An assembly according to any one of the preceding claims, characterized in that each nut (30i) of the set is provided with slots (36i 1, 36i ₂ ,

36i ₃ , 36i ₄ ) which radially connect the hole (30Ci) and the outer lateral surface (30A ₁ ) of the nut and extend only over a portion of the nut along the central axis (Z _{1 -} Z ₁ ) of its outer side surface and which, preferably, are distributed substantially uniformly around the periphery of the nut.

6. An assembly according to claim 5, characterized in that each slot

(3G _{1 1} ) includes, on the one hand, a first elongated portion (37n) which extends parallel to the central axis (Z ₁ -Z ₁ ) of the outer lateral surface (30A ₁ ) of the nut ( 3O ₁ ), from one of the front surfaces (30B ₁ , 30D ₁ ) of the nut, preferably from one and the other of these front surfaces for respectively two successive slots along the periphery of the nut, and, secondly, a second elongated portion (3S ₁ 1) which extends in the circumferential direction of the nut, from the end of the first portion, opposite to the front surface of the nut since which this first part extends.

7. Assembly according to any one of the preceding claims, characterized in that the osteosynthesis body (10) is provided on its proximal surface (10B) and around the opening of the orifice (H ₁ , 11 ₂ , 11 ₃ ), angular graduations (13i, 13 ₂ , 13 ₃ ) centered on the axis (X ₁ -X ₁ , X ₂ -X ₂ , X ₃ -X ₃ ) of the orifice, while the or each nut (2O ₁ , 2O ₃ ), associated with a non-zero angulation value, is provided, on its front surface (30B ₁ , 30B ₃ ) on which opens the diverging side of the hole (30C ₁ , 30C ₃ ), a marker (33 ^ 33 ₃₎ for the angular positioning of the nut around the central axis (Z _1- Z _1, Z ₃ -Z ₃₎ of its outer lateral surface (30A _1, 30A _3), this marker being preferably located in the plane containing both the central axis the outer side surface of the nut and the central axis (Wi-Wi, W ₃ -W ₃ ) of the nut hole.

8. Surgical system for practicing osteosynthesis, comprising:

an osteosynthesis assembly (2) according to any preceding claim, wherein the head (22 _1; 22 ₂ , 22 ₃ ) and the stem (2I ₁ , 21 ₂ ,

21 ₃ ) of the anchoring member (2O ₁ , 2O ₂ , 2O ₃ ) are traversed right through by a bore (24!, 24 ₂ , 24 ₃ ) centered on the longitudinal axis (Y ₁ -Y ₁ , Y ₂ -Y ₂ , Y ₃ -Y ₃ ) of the stem,

a spindle (50) fitted on the bore of the anchoring member belonging to the osteosynthesis assembly, in order to thread and guide this organ around this spindle, and

at least one ancillary (40; 40 ') bone implantation of the spindle through the orifice (H ₁ , 11 ₂ , 11 ₃ ) of the osteosynthesis body (10) of the osteosynthesis assembly, following an implantation direction which, in use, forms with the axis (X ₁ -X ₁ , X ₂ -X ₂ , X ₃ -X ₃ ) of the orifice of the body an angle (β, β ') whose value is equal to one of the angulation values associated with the nuts (3O ₁ , 3O ₂ , 3O ₃ ) of the set of nuts belonging to the set of osteosynthesis, this implantation direction being either specific to each ancillary when several ancillaries are provided respectively associated with different nuts of the game, is adjustable when the same ancillary is provided for different nuts of the game.

9. System according to claim 8, characterized in that the or each jig (40) has a distal end (42) adapted to turn the nut ₍₁ 3O, 3O ₃₎ which, from the set of nuts belonging to whole bone (2) presents an angle of value equal to that of the direction of implantation defined by the ancillary tool, rotating around the central axis (Z _1- Z _1, Z ₃ -Z ₃ ) of the outer lateral surface (30A ₁ , 30A ₃ ) of this nut and thus screw this nut into the hole (H ₁ , 113) of the osteosynthesis body (10) belonging to the osteosynthesis assembly.

10. System according to one of claims 8 or 9, characterized in that the or each ancillary (40; 40 ') is provided at its distal end (42; 42'), a means (47; 47 '). ) for locating, with respect to the osteosynthesis body (10) belonging to the osteosynthesis assembly (2), the angular position of this distal end about the axis (X ₁ -X ₁ , X ₂ -X ₂ , X ₃ -X ₃ ) of the orifice (H ₁ , 11 ₂ , 11 ₃ ) of the osteosynthesis body.