Vertebral stabilization device

Abstract

The present invention relates to a vertebral stabilization device comprising at least two bolts, each bolt having a first portion engaged in a vertebra and a second portion separated from the first portion by a flange. The device further comprises at least a first connecting rod for connecting the bolt, and at least a first fixing assembly and a second fixing assembly for fixing the rod to the bolt. Each securing assembly comprises at least one clip engageable on the second portion of one of the bolts, said clip being arranged to clamp one end of the rod, and a nut designed to be screwed onto the second portion and to clamp the clip directly or indirectly against the flanges of the bolts. Each securing assembly is designed to create at least one ball joint connection between the clip and the second portion of the bolt.

Description

Background of the Invention

[0002] The present invention relates to the field of surgical implants, and more particularly to vertebral stabilization devices implanted in humans or animals for treating spinal pathologies.

[0003] There are many vertebral stabilization devices, the general principle of which is to connect adjacent vertebrae via rods.

[0004] In a first device, a rod (sometimes called a beam) is fixed on either side of the vertebrae to connect along a plane roughly parallel to the median sagittal plane of the spine. This device makes it possible to obtain a very good stabilization of the vertebrae relative to each other, but has the major drawback of significantly limiting the mobility of the column, hindering or even preventing specific movements of the patient. The rod is inserted directly into the pedicle bolt heads, which requires perfect alignment of the bolt heads with each other, which is sometimes difficult to achieve.

[0005] In a second device forming the subject of patent application WO2018 / 019792, the rods are fixed so that they cross each other in the median sagittal plane of the spine. The latter device makes it possible to maintain a certain mobility between the two vertebrae connected by the device while enhancing their stability. The rod has a first circular annular end and a second oblong annular end. During implementation, the rings are respectively engaged on the threaded portions extending the pedicle bolts, screwed directly into the vertebrae. The final fixation of the vertebrae is accomplished by screwing a nut onto each threaded portion to block the ring of the rod by clamping, thereby fixing the position of the rod relative to the pedicle bolt. This fixing principle, although simple, is difficult to adjust precisely. In addition, during the clamping of the nut, the rod can move slightly around the fixing element, thereby changing the initial adjustment made by the surgeon. Therefore, the implementation of this device requires great control and the surgeon is very meticulous, which usually has the result of extending the duration of the intervention.

[0006] Purpose of the Invention

[0007] In particular, the object of the invention is to at least partially overcome the above mentioned drawbacks by proposing a vertebral stabilization device which is compact and easy and quick to implant. Summary of the invention

[0008] To this end, a vertebral stabilization device is provided, comprising at least two bolts, each having a first threaded portion engaged in the vertebra and a second threaded portion separated from the first threaded portion by a flange. The device of the invention also comprises at least one first connecting rod having two opposite ends to connect one of the two threaded portions of the bolt to the other, and at least one first fixing assembly and a second fixing assembly to fix the ends of the rod to the bolt. Each fixing assembly of the device as the subject of the invention comprises at least one clamp capable of engaging on the second threaded portion of one of the bolts, the clamp being arranged to clamp one end of the rod, and comprising a nut having a lower bearing surface, the nut being designed to be tightened on the second threaded portion and to clamp the clamp directly or indirectly against the upper surface of the flange of the bolt. Each fixing assembly is designed to produce at least one ball joint connection between the clamp and the second threaded portion.

[0009] Thus, according to the invention, the surgeon can perform the stabilization of at least two vertebrae by using at least one stabilization device according to the invention. Stabilization of the vertebrae is easily performed by means of a rod simply fixed by a clamp of the fixation assembly, also spanning the median sagittal plane of the spine, or according to a conventional parallel mounting in a plane parallel to the median sagittal plane of the column. The device according to the invention not only enables an easier and more reliable fixation of the rod, but also enables the restoration of the mounting, for example in patients who have been operated with an extension of the mounting, without having to disassemble the assembly as is done with currently available instruments.

[0010] Preferably, the lower bearing surface of the nut and the upper bearing surface of the flange are spherical cap-shaped concave surfaces identical to each other.

[0011] According to a first particular arrangement of the invention, the clamp of at least the first fixing assembly comprises a first jaw having a spherical cap-shaped raised outer surface, in this case bearing directly on the upper surface of the flange, and a second jaw having a spherical cap-shaped raised outer surface, and the first fixing assembly comprises a first bearing sleeve for the nut, said first bearing sleeve having a complementary concave lower front surface to bear against the spherical cap-shaped raised outer surface of the second jaw. The first bearing sleeve may be different from the nut. In particular, the first bearing sleeve comprises an upper front surface of the spherical cap-shaped raised surface, which is complementary to the lower surface of the nut to bear against it.

[0012] According to a second particular arrangement of the invention, at least the clamp of the second fixing assembly comprises a first jaw and a third jaw, the first jaw having a complementary spherical cap-shaped convex outer surface to bear against the lower surface of the nut, and the third jaw having a spherical cap-shaped concave outer surface. The second fixing assembly also comprises a second bearing sleeve having a complementary upper front surface to bear on the spherical cap-shaped concave outer surface of the third jaw. In particular, the second bearing sleeve has a spherical cap-shaped concave lower front surface to bear on the upper surface of the flange. In this case, the nut makes it possible to clamp the clamp indirectly against the upper surface of the flange of the bolt, in fact according to this second arrangement, the second bearing sleeve is located between the flange and the clamp.

[0013] Thus, the presence of the bearing sleeve in the first or second arrangement makes it possible to adjust the height of the fixation assembly on the second threaded portion of the bolt, so that the positioning of the rod is adapted to the morphology of the patient and the pathology to be treated. In particular, when vertebral stabilization is performed by crossing the rods around the median sagittal axis, the bearing sleeve makes it possible to adjust the height of the rods relative to each other without friction or controlled contact.

[0014] According to a third arrangement of the invention, the second fixing assembly comprises two clamps, a lower clamp and an upper clamp. The lower clamp comprises a first jaw and a second jaw, the first jaw having a complementary spherical cap-shaped convex outer surface to bear directly on the upper surface of the flange, and the second jaw having a spherical cap-shaped convex outer surface. The upper clamp comprises a first jaw and a third jaw, the first jaw having a complementary spherical cap-shaped convex outer surface to bear against the lower surface of the nut, and the third jaw having a spherical cap-shaped concave outer surface complementary to the convex outer surface of the second jaw of the first clamp, the concave outer surface of the third jaw of the second clamp bearing on the convex outer surface of the second jaw of the first clamp.

[0015] According to the invention, each clip comprises an elastically deformable portion connecting the jaws to each other so that the jaws are movable relative to each other between an open position and a closed position.

[0016] According to a preferred embodiment of the invention, the first jaw is provided with a hole engaged in the second threaded portion of the bolt. The hole comprises a first frustoconical portion and a second cylindrical portion. The first portion has a large cross section opening onto the outer surface of the first jaw and a small cross section combined with the cylindrical cross section of the second portion, which opens onto the inner surface of the first jaw.

[0017] The second jaw is also provided with a hole coupled to the second threaded portion of the bolt. In this case, the hole comprises a first truncated cone-shaped portion and a second truncated cone-shaped portion, the first portion having a large cross section opening onto the outer surface of the second jaw and a small cross section coupled to the small cross section of the second portion. The second portion has a large cross section opening onto the inner surface of the second jaw. The common rotation center of the surfaces in contact with the nut and the flange is arranged at the center of the small cross section of the first and second portions. Symbolically, the hole has a shape similar to a diabolo.

[0018] Optionally, the flange of the bolt may be removable.

[0019] The specific holes of the clip, the shape of the outer surface of the clip, and the shape of the outer surface of the flange, and the shape of the lower surface of the nut, like the shapes of the upper and lower front surfaces of the bearing sleeve, make it possible to perform a ball-joint connection between the different elements of the device (flange, clip, bearing sleeve, nut), which allows the surgeon to adjust the positioning of the rod extremely precisely and easily according to the morphology of the patient and the pathology to be treated. Once the optimal positioning is obtained, the latter are blocked by simply clamping a nut on each bolt.

[0020] According to a particular embodiment of the invention, the rod has a constant cross section over its entire length. Preferably, the rod may be curved. In this case, the term "rod" refers to the entire extension, which is narrow relative to its length, regardless of its cross section, according to the ordinary meaning of the word and the meaning of rod, which refers to the entire portion.

[0021] Preferably, the second threaded portion of each bolt is provided with an end portion, which is arranged to be rotatably connected to a tool for screwing the bolt into the vertebra. It also has a breaking piece capable of separating the end portion from the second threaded portion by breaking.

[0022] Thus, at the end of the intervention, after the bolts have been screwed into the vertebrae and after the device according to the invention has been placed in place, the surgeon can shorten each bolt at the break to make the device more compact and more comfortable for the patient.

[0023] Other characteristics and advantages of the invention will emerge on reading the following description of particular and non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Reference will be made to the accompanying drawings, in which:

[0025] [ Figure 1 ]: top view and slight perspective view of three vertebrae equipped with a device according to a specific embodiment of the present invention;

[0026] [ Figure 2]: a schematic longitudinal section of one of the bolts of the device, the bolt being provided with a fixing assembly according to a first configuration, the fixing assembly comprising a clip, a bearing sleeve and a nut;

[0027] [ Figure 3 ]: a schematic longitudinal section of one of the bolts of the device, the bolt being provided with a fixing assembly according to a second configuration, the fixing assembly comprising a bearing sleeve, a clamp, and a nut;

[0028] [ Figure 4 ]: a perspective schematic diagram of a bolt of the device equipped with a fixing assembly according to a third configuration, the fixing assembly comprising a first clamp, a second clamp and a nut;

[0029] [ Figure 5 ]:The bolt is along Figure 4 A schematic diagram of a longitudinal section of a plane V;

[0030] [ Figure 6 ]:The bolt is located along the fixing component. Figure 4 Schematic diagram of a longitudinal section of plane VI, the fixing assembly being connected via a ball joint and tilted relative to the bolt;

[0031] [ Figure 7 ]: Exploded diagram of the bolt and fixing assembly;

[0032] [ Figure 8 ]:The bolt and fixing assembly are along Figure 4 An exploded schematic diagram of a longitudinal section of plane V;

[0033] [ Fig. 9 ]: 3D schematic diagram of the pin of the clip. DETAILED DESCRIPTION

[0034] refer to Figures 1 to 9 The present invention relates to a vertebral stabilization device, comprising:

[0035] - at least two bolts 1a; 1b; each provided with a flange 2;

[0036] - at least one first connecting rod 3;

[0037] - at least one first fixing assembly and one second fixing assembly for fixing the ends of the rod 3 to the bolts 1a and 1b respectively. Each fixing assembly comprises at least one clamp 50.1, 50.2 and a nut 80, the clamp 50.1, 50.2 being able to engage on the second threaded portion 1.2 of one of the bolts and being designed to clamp the end of the rod 3.

[0038] according to Figure 1 In the example of a spinal device shown, three adjacent vertebrae Va, Vb, Vc are stabilized with a vertebral stabilization device according to the present invention.

[0039] In this case, the device comprises two bolts 1a, 1'a on vertebra Va; two bolts 1b, 1'b on vertebra Vb; and two bolts 1c, 1'c on vertebra Vc. All the bolts 1, 1' are identical, the letters a, b, c being used only to distinguish the bolts according to the vertebra in which they are implanted. Each bolt thus comprises a first threaded portion 1.1, which is threaded in a manner similar to that of a vertebra. Figure 1 Not shown, but in Figures 2 to 7 It can be seen in FIG. 2 that the first threaded portion 1 .1 engages in the vertebra and that the second threaded portion 1 .2 is separated from the first threaded portion 1 .1 by the flange 2 .

[0040] The vertebrae Va, Vb, Vc to be mounted are usually prepared before receiving the stabilization device. Conventionally, the articulations or spinous processes of the vertebrae can be reduced in advance and the vertebrae pre-drilled to receive the bolts.

[0041] As described above, the first threaded portions 1a.1, 1b.1, 1c.1 of the bolts 1a, 1b, 1c are inserted into the vertebrae Va, Vb and Vc on either side of the mid-sagittal plane in a staggered manner and alternately. Thus, the first portion 1a.1 of the bolt 1a is inserted into the vertebra Va on the left side of the mid-sagittal plane, the first portion 1b.1 of the bolt 1b is inserted into the vertebra Vb on the right side of the mid-sagittal plane, and the first portion 1c.1 of the bolt 1c is inserted into the vertebra Vc on the left side of the mid-sagittal plane. Symmetrically, the first portion 1'a.1 of the bolt 1'a is inserted into the vertebra Va on the right side of the mid-sagittal plane, more or less facing the bolt 1a. In the same way, the first part 1'b.1 of the bolt 1'b is inserted into the vertebra Vb on the left side of the mid-sagittal plane, more or less facing the bolt 1b, and the first part 1'c.1 of the bolt 1'c is inserted into the vertebra Vc on the right side of the mid-sagittal plane, more or less facing the bolt 1c. Thus, each vertebra Va, Vb, Vc is equipped with two bolts 1a and 1'a; 1b and 1'b; 1c and 1'c, respectively.

[0042] The following description of the bolts applies to all bolts, provided that all bolts are identical. As mentioned above, each bolt 1 comprises a first portion 1.1 and a second portion 1.2 separated by a flange 2. The first portion 1.1 is fully inserted into the bone of the vertebra up to the flange 2. The flange 2 thus rests on the surface of the vertebra, bearing on the bone, and the second portion of the bolt 1.2 protrudes from the vertebra.

[0043] The surgeon knows how to drill the holes and position the bolts 1 correctly according to the morphology of the patient.

[0044] The skilled person will know how to shape the first part 1.1 so as to facilitate its engagement in the bone. For example, the first part may be self-tapping and have an end shaped in the form of a tip. In a variant, the first part may also be self-drilling.

[0045] The flange 2 of the bolt 1 separating the first part 1.1 and the second part 1.2 has a spherical cap convex lower surface in contact with the bone of the vertebra and a spherical cap concave bearing upper surface. A person skilled in the art will know how to adjust the diameter and convexity of the flange according to the patient's anatomy and the mechanical stresses experienced.

[0046] Thus, when the bolt 1 is fixed, the second portion 1.2 of the bolt 1 protrudes from the vertebra. The second portion 1.2 is threaded to receive the fixing assembly F. Preferably, the second threaded portion 1.2 is provided with an end portion designed to be rotatably connected to a threading tool. Figure 2 The end portion shown in the figure may thus include a footprint 1.3 of a shape complementary to the shape of the tip of a screwdriver. As non-limiting examples, the footprint may be hexagonal, cross-head-shaped, star-shaped or triangular. Furthermore, the second threaded portion 1.2 may include a breaking piece 1.4 which, when the surgical procedure is concluded, is able to separate the end portion from the second threaded portion by breaking.

[0047] A person skilled in the art will know how to manufacture a bolt which in this case is made in a single piece and which is made continuously between the first bolt part, the second bolt part and the flange of a biocompatible and stainless steel material having sufficient mechanical and chemical resistance for the application under consideration.

[0048] Those skilled in the art will know how to determine the diameter and length of the bolt to best suit the patient's age, morphology and bone quality. As an illustration, conventionally, the length of the bolt may be between 65 mm and 90 mm.

[0049] According to this particular embodiment of the invention, the devices each comprise two pairs of connecting rods respectively referenced 3a, 3b and 3'a, 3'b. Each rod has two opposite ends to connect the second threaded portions of two bolts to each other in pairs.

[0050] Therefore, if Figure 1As shown, the first connecting rod 3a will connect the second part 1a.2 of the bolt 1a to the second part 1b.2 of the bolt 1b, and the second connecting rod 3b will connect the second part 1b.2 of the bolt 1b to the second part 1c.2 of the bolt 1c, so that the bolts 1a, 1b, 1c are connected in pairs. In the same way, the third rod 3'a will connect the second part 1'a.2 of the bolt 1'a to the second part 1'b.2 of the bolt 1'b, and the fourth rod 3'b will connect the second part 1'b.2 of the bolt 1'b to the second part 1'c.2 of the bolt 1'c, so that the bolts 1'a, 1'b, 1'c are connected in pairs. The rods 3a, 3'b are therefore parallel to each other because the rods 3'a and 3b are also parallel to each other. The rods 3a and 3'a stabilize the vertebrae Va and Vb to each other, and the rods 3b and 3'b stabilize the vertebrae Vb and Vc to each other, crossing each other in the median sagittal plane of the column between the vertebrae Va and Vb and between the vertebrae Vb and Vc, respectively.

[0051] In this case, each rod 3 is made of a biocompatible material and has a constant cross section over its entire length. In this case, the cross section is circular.

[0052] The rod 3 may be made of any sufficiently rigid biocompatible material to obtain stability of the vertebrae relative to each other. For example, a material with a Young's modulus between 3.6 GPa and 60 GPa will be selected. For example, the material may be a composite material comprising a mixture of carbon and polyetheretherketone (PEEK) fibers.

[0053] A person skilled in the art is able to determine the diameter of the cross section of the rod according to the materials used, the mechanical characteristics sought and the anatomy of the patient. He also knows how to determine the length of the rod to adapt it to the morphology and pathology of the patient and to determine the length of the rod according to the rod being placed parallel to the mid-sagittal plane or according to the rod being placed crosswise to each other in the mid-sagittal plane.

[0054] Preferably, according to a particular embodiment of the invention, the rods are curved so as to facilitate their implementation and limit interference with the central portion of the coupled vertebrae.

[0055] The fixation of each end of the rod 3 to one of the bolts 1 is ensured by a fixing assembly F which engages on the second threaded portion of the bolt.

[0056] Each fixing assembly F according to the invention comprises at least one clip 50.1, 50.2, which can be engaged on the second threaded portion 1.2 of one of the bolts 1 and is designed to clamp the end of the rod 3, and a nut 80 having a lower bearing surface and designed to be tightened on the second threaded portion 1.2 by clamping the clip 50.1, 50.2 against the upper surface of the flange 2 of the bolt 1. Each fixing assembly F is designed to produce a ball joint connection between the clip 50.1, 50.2 and the second threaded portion 1.2. Preferably, the lower bearing surface of the nut 80 and the upper bearing surface of the flange 2 as described above are spherical cap-shaped concave surfaces that are identical to each other.

[0057] The fixing assembly F may have several configurations, according to which it is located on a bolt implanted in one of the end vertebrae of the part of the assembly column (vertebrae Va, Vc) or on a bolt implanted in an intermediate vertebrae (vertebrae Vb). Thus, the fixing assembly F will comprise a bearing sleeve of two configurations adapted to the end vertebrae or a second clamp of a configuration adapted to the intermediate vertebrae.

[0058] See also Figure 2 , the fixing assembly F1 according to a first configuration comprises a clip 50.1, a bearing sleeve 60 and a nut 80. In this case, the clip 50.1 is more or less rectangular in shape and comprises two claws 51, 52 connected by an elastically deformable portion, in this case a metal spring pin 55, so that the claws can move against each other between an open position and a closed position. Fig. 9 The pin 55 shown comprises a first hook-shaped tab 55.1 elastically surrounding a portion of the first part 51.1 opposite to the second part 51.2 and two hook-shaped tabs 55.2 elastically surrounding a portion of the first part 52.1 opposite to the second part 52.2. A person skilled in the art will know how to make the elastically deformable part differently. For example, they can make the clip into a single part, with the two claws connected to each other by a single-piece elastically deformable part. The two claws can be connected to each other by a hinge, optionally associated with a helical spring.

[0059] Each claw 51 comprises a first portion 51.1 or portion for connection to the bolt 1, which is intended to engage on the second portion 1.2 of the bolt, and a second portion or portion for connecting the rod 3, which projects laterally relative to the first portion 51.1 and is designed to receive one of the ends of one of the rods 3. In this case, the first portion 51.1 is more or less parallelepiped in shape, with a square cross section having sides substantially equal to or slightly greater than the diameter of the flange 2. The first portion 51.1 comprises an inner surface 51.3 facing the claw 52 (and therefore, turned inward from the clamp 50.1) and opposite an outer surface 51.4 turned outward from the clamp 50.1. The inner surface 51.3 is a flat surface. The outer surface 51.4 is a spherical cap shape and convex shape complementary to the upper surface of the flange 2, so as to be able to bear on a surface thereon.

[0060] The first portion 51.1 of the first claw 51 is provided with a hole 51.5 to engage on the second threaded portion 1.2 of the bolt 1. The hole 51.5 opens on one side perpendicular to the inner surface 51.3 of the first portion 51.1 of the clamp and on the other side on the outer surface 51.4. In this case, the hole 51.5 comprises along the central axis a first truncated cone-shaped portion with a large cross-section opening on the outer surface 51.4 and a small cross-section combined with the cylindrical cross-section of the second portion, which opens on the inner surface 51.3.

[0061] The second portion 51 . 2 comprises a semi-cylindrical recess 51 . 6 , the central axis of which is perpendicular to the central axis of the hole 51 . 5 and the radius of which is substantially equal to or slightly smaller than the radius of the rod 3 .

[0062] The second claw 52 itself also comprises a first portion 52.1 or portion for connection to the bolt 1, which is intended to be coupled to the second portion 1.2 of the bolt 1, and a second portion 52.2 or portion for connection to the rod 3, which projects laterally relative to the first portion and is designed to receive one of the ends of one of the rods.

[0063] In this case, the first portion 52.1 is more or less parallelepiped in shape, has the same square cross section as the first portion 51.1, and comprises an inner surface 52.3 facing the claw 51 (and therefore turned inwards from the clamp 50.1) and an opposite outer surface 52.4 turned outwards from the clamp 50.1. The inner surface 52.3 is a flat surface. The outer surface 52.4 is spherical cap-shaped and convex.

[0064] The first portion 52.1 of the second claw 52 is also provided with a hole 52.5 to engage on the second threaded portion 1.2 of the bolt 1. In this case, the hole 52.5 comprises a first truncated cone portion having a large cross section opening on the outer surface 52.4 and a small cross section combined with a small cross section of the second portion, and a second truncated cone portion having a large cross section opening on the inner surface 52.3.

[0065] The second portion 52 . 2 is identical to and faces the second portion 51 . 2 , such that the grooves 51 . 6 and 52 . 6 delimit a cylindrical housing to receive the end of the rod 3 .

[0066] The clamp 50.1 is formed by assembling the first jaw 51 with the second jaw 52 by means of a pin 55. In the closed position, the grooves 51.6, 52.6 of the second parts 51.2, 52.2 of the jaws 51 and 52 form a housing of a smaller circular cross section than the end of the rod 3 so that the end of the rod 3 can be surrounded there.

[0067] The fixing assembly F1 further comprises a first bearing sleeve 60 of the nut 80. The bearing sleeve is preferably different from the nut 80, such as Figure 2 As shown. The first bearing sleeve 60 defines a through-conduit that can be engaged on the second portion 1.2 of the bolt 1. In this case, the conduit is cylindrical. In this case, the bearing sleeve 60 comprises a spherical cap-shaped convex upper front surface 60.2 and a spherical cap-shaped concave lower front surface 60.1, the upper front surface 60.2 being complementary to the lower surface of the nut 80 to bear against the lower surface of the nut 80, and the lower front surface 60.1 being complementary to the outer surface 52.4 of the first portion 52.1 of the second claw 52.

[0068] Thus, the bolt 1 equipped with the fixing assembly F1 according to the first configuration comprises, successively engaged along the second bolt portion 1.2: a clip 50.1, whose first jaw 51 is in contact with the flange 2, and whose second jaw 52 bears on the lower front surface 60.1 of the first bearing sleeve 60, the upper front surface 60.2 of which bears on the lower surface of the nut 80. The holes of the first and second jaws 51, 52 and the outer surfaces 51.4, 52.4 engaging with the upper surface of the flange 2 and the lower surface of the bearing sleeve 60 make it possible to produce a ball joint connection around the bolt.

[0069] It should be noted that the center of the spherical cap of the outer surface 51.4 and the center of the spherical cap of the outer surface 52.4 are combined and arranged at the center of the small cross-section of the first and second parts of the hole 52.5.

[0070] exist Figure 3 , a fixing assembly F2 is shown according to a second configuration. The fixing assembly F2 comprises a second bearing sleeve 70, a clip 50.2 and a nut 80.

[0071] The clamp 50.2 consists of two claws 51, 53 connected by an elastically deformable pin 55: a first claw 51 and a third claw 53.

[0072] The first claw 51 is identical to the claw described above, but is positioned to bear against the lower surface of the nut 80. Recalling that the lower bearing surface of the nut 80 and the upper bearing surface of the flange 2 have the same shape, the outer surface 51.4 can equally bear against one or the other by forming a ball joint connection.

[0073] The third claw 53 itself also includes a first part 53.1 or a part for connecting to the bolt 1, which is used to engage on the second part 1.2 of the bolt 1; and a second part 53.2 or a part for connecting to the rod 3, which protrudes laterally relative to the first part 53.1 and is designed to receive one end of a rod.

[0074] In this case, the first portion 53.1 is more or less parallelepiped in shape with a square cross section, identical to the shape of the first portion 51.1, and comprises an inner surface 53.3 facing the jaw 51 (and therefore turned inwards from the clamp 50.2) and an opposite outer surface 53.4 turned outwards from the clamp 50.1. The inner surface 53.3 is a flat surface. A spherical cap and a concave outer surface 53.4.

[0075] The first part 53.1 of the third jaw 53 is also provided with a hole 53.5 to engage on the second threaded part 1.2 of the bolt 1. The hole 53.5 opens downwards on the outer surface 53.4 and opens upwards on the inner surface 53.3. Given the concavity of the outer surface 53.4 into the first part 53.1, the hole 53.5 has a minimum length.

[0076] The second portion 53 . 2 is identical to and faces the second portion 51 . 2 , such that the grooves 51 . 6 and 53 . 6 delimit a cylindrical housing to receive the end of the rod 3 .

[0077] The second bearing sleeve 70 defines a through-duct which can be engaged on the second portion 1.2 of the bolt 1. In this case, the duct is cylindrical. It can be threaded or non-threaded. In this case, the second bearing sleeve 70 comprises a convex and spherical cap-shaped lower front surface 70.1 complementary to the upper surface of the flange 2, and a concave and spherical cap-shaped upper front surface 70.2 complementary to the concave outer surface 53.4 of the first portion 53.1 of the third claw 53.

[0078] Thus, the bolt 1 is provided with a fixing assembly in a second configuration, successively joined along the second portion 1.2 of the bolt 1, comprising: a second bearing sleeve 70, the lower surface 70.1 of which bears against the flange 2; a clip 50.2, the outer surface 53.4 of the third jaw 53 of which bears against the upper front surface 70.2 of the second bearing sleeve 70, and the outer surface 51.4 of the first jaw 51 of which bears against the lower bearing surface of the nut 80. The hole 51.5 of the first jaw 51, and the outer surfaces 51.4, 53.4 engaging with the lower surface of the nut 80 and the upper front surface 70.2 of the second bearing sleeve 70, make it possible to produce a ball joint connection of the clip 50.2 around the bolt 1.

[0079] It should be noted that the center of the spherical cap of the outer surface 51.4 and the center of the spherical cap of the outer surface 53.4 are combined together.

[0080] See also Figures 4 to 8 According to the third configuration, the fixing assembly F3 comprises two clips, a lower clip 50.1 and an upper clip 50.2. The lower clip 50.1 is identical to the clip of the fixing assembly F1 described above, and the clip 50.2 is identical to the clip of the fixing assembly F2 described above. The outer surface 51.4 of the claw 51 of the lower clip 50.1 bears on the upper surface of the flange 2; the outer surface 52.4 of the claw 52 of the lower clip 50.1 bears against the outer surface 53.4 of the claw 53 of the upper clip 50.2; the outer surface 51.4 of the claw 51 of the upper clip 50.2 bears on the lower surface of the nut 80. Therefore, the ball joint connection of the clips 50.1 and 50.2 on the bolt 1 is ensured.

[0081] Therefore, the bolt 1 equipped with the fixing assembly F3 according to the third configuration successively includes a lower clip 50.1, the first claw 51 of which has an outer surface 51.4 that is supported against the upper surface of the flange 2, and the second claw 52 of the lower clip 52 has an outer surface 52.4 that is supported against the outer surface 53.4 of the third claw 53 formed with another first claw 51; an upper clip 50.2, the outer surface 51.4 of the first claw 51 of which is supported against the lower surface of the nut 80. The holes of the first claws 51 of the first lower clip 50.1 and the second upper clip 50.2, the "diabolo-shaped" holes of the second claws 52 of the lower clip 50.1, and the complementary spherical cap-shaped surfaces in contact with the lower surface of the nut 80 (the outer surface 51.4 of the upper clip 50.2 and the upper surface of the nut 80; the outer surface 51.4 of the lower clip 50.1 and the upper surface of the flange 2; the outer surface 52.4 of the lower clip 50.1 and the outer surface 53.4 of the upper clip 50.2) make it possible to create a ball joint connection of the two clips (individually or collectively) around the bolt 1.

[0082] It should be noted that the centers of the spherical caps of the two outer surfaces 51.4 are combined and arranged in the center of the small cross-section of the first and second frustoconical portions of the hole 52.5.

[0083] Therefore, in Figure 1 In the implant shown, in order to stabilize three adjacent vertebrae Va, Vb, Vc, the surgeon will use six bolts 1, four rods 3 and six fixation assemblies.

[0084] Therefore, the first vertebra Va is provided with a bolt 1 a provided with a fixing component F1 on the left side of the mid-sagittal plane, and a bolt 1 ′ a provided with a fixing component F2 is provided on the right side of the mid-sagittal plane.

[0085] On the left side of the mid-sagittal plane, the second vertebra Vb is equipped with a bolt 1'b provided with a fixing assembly F3, and on the right side of the mid-sagittal plane, the second vertebra Vb is equipped with a bolt 1b provided with a fixing assembly F3. On the left side of the mid-sagittal plane, the third vertebra is equipped with a bolt 1c provided with a fixing assembly F2, and on the right side of the mid-sagittal plane, the third vertebra is equipped with a bolt 1'c provided with a fixing assembly F1. Once the bolts are inserted into the vertebrae, the surgeon positions the rods 3a, 3'a, 3b, 3'b starting from the rod closest to the spine. Thus, the rod 3'a has a first end fixed by the clamp 50.1 of the fixing assembly F1 of the bolt 1'a, a second end of the rod 3'a fixed by the lower clamp 50.1 of the fixing assembly F3 of the bolt 1'b. The rod 3b itself is fixed to each of its ends by the lower clamp 50.1 of the fixing assembly F3 of the bolt 1b and the clamp 50.1 of the fixing assembly F1 of the bolt 1c, respectively.

[0086] Then, the rods 3a and 3'b are fixed respectively. The rod 3a is fixed by a first end to the clamp 50.2 of the fixing assembly F2 of the bolt 1a, and by a second end to the upper clamp 50.2 of the fixing assembly F3 of the bolt 1b. The rod 3'b itself is fixed between the clamp 50.2 of the bolt 1'b and the clamp 50.2 of the bolt 1'c.

[0087] The rods 3a and 3'b are fixed so that they pass over the rods 3'a and 3b respectively, and the rods cross each other approximately in the mid-sagittal plane. Therefore, the rods 3'a and 3a stabilize the vertebrae Va and Vb against each other, and the rods 3'b and 3b stabilize the vertebrae Vb and Vc against each other.

[0088] Thanks to the possibility of the clamp rotating around each bolt 1 and the ball-joint connection of each bolt 1, which is realized by means of the holes of the claws of the clamp, the surgeon will know how to adjust the positioning of the rods. This thus enables very precise adjustment in three dimensions: in height by means of the positioning of the clamp along the second bolt portion, in length by means of the rotation of the clamp around the bolt and the tilting due to the ball-joint connection, while maintaining a very high compactness of the device according to the invention. Once the rods are in their optimal position, the surgeon will adjust the rods by clamping the nut 80 on each bolt and in the fracture 1.4 (at Figure 2 The device is secured by cutting the second portion of each bolt at a position shown in FIG.

[0089] For other pathologies, only two adjacent vertebrae can be stabilized. In this case, the assembly used includes two pairs of bolts (1a, 1b and 1'a, 1'b). Bolts 1'a, 1'b are equipped with a fixing assembly F1, while bolts 1a and 1b are equipped with a fixing assembly F2. Bolts 1a and 1'a are inserted on both sides of the first vertebra, respectively on the left and right side of the mid-sagittal plane, and bolts 1b and 1'b are inserted on both sides of the second vertebra, respectively on the right and left side of the mid-sagittal plane. The first rod 3 is then fixed between the bolts 1'a and 1'b, and the second rod 3 is fixed between the bolts 1a and 1b.

[0090] The device for stabilizing vertebrae according to the invention is thus easy to implement and unobtrusive. The number of bolts per device is determined according to the number of vertebrae to be installed. The use of the device according to the invention enables an optimal and precise adjustment of the position of the rods with respect to the patient's pathology and its morphology. Moreover, as the pathology progresses, the adjustment can be easily achieved by simply changing the corresponding position of the clamp, by changing the fixing assembly on the bolt, or by changing the screw if it is no longer suitable, without having to consider a long operation on the patient.

[0091] This high degree of precision in adjusting the positioning of the rods, choosing their length and their adjustment on the jaws of the clamp makes it a custom-made system adapted to each patient, despite including the fixing elements which are themselves of standard manufacture.

[0092] To facilitate implementation of the device, each device element (bolt, fixing assembly: claw, bearing sleeve, nut and rod) can form a marking or color theme so that the element can be quickly identified and can also be tracked from manufacturing to implementation in the patient. The marking can be done by any known biocompatible method.

[0093] Of course, the invention is not limited to the embodiments described but comprises any variant coming within the ambit of the invention as defined by the claims.

[0094] Specifically, in this case, the instrumented vertebrae are adjacent, but they may not be. Therefore, the length of the rod must simply be adjusted according to the distance between the two vertebrae to be installed.

[0095] In this case, therefore, the rods are fixed in a crossed manner between the vertebrae, but the device according to the invention makes it possible to absolutely fix the rods parallel to the median sagittal plane. Moreover, although in this case a single fixation mode is provided (fixation with crossed rods), depending on the patient's pathology, it is possible to provide an assembly using the device according to the invention to position certain vertebrae in a crossed manner and other parallel vertebrae.

[0096] In this case, the rod has a circular cross section, but it may have an elliptical, triangular, rectangular, polygonal cross section or the like.

[0097] In this case, the rod has a constant cross section, but it may have a cross section that is narrower at the ends than in the center, or vice versa, wider at the ends than in the center.

[0098] In this case, the rods have a predetermined length, but they can be custom cut to the required length.

[0099] The rods may be straight rather than curved.

[0100] In this case, the bolts are solid, but they could be hollow to enable fixation of pins or to facilitate percutaneous surgery.

[0101] In this case, the jaws have a substantially parallelepiped shape, but may have any shape, such as cylindrical, polyhedral or ovoid, etc. The recess of the second portion may have an angular or polygonal cross section, so that once the two jaws of the clamp are closed, the second portion of the jaws forms a channel of square or polygonal cross section.

[0102] In this case, the device may comprise a nut integrating the bearing sleeve 60 in one single part, and / or a bolt integrating the bearing sleeve 70 in one single part, and / or a bolt and a nut as described.

[0103] In this case, the fixation assemblies F1 and F2 comprise a support sleeve, but this can be replaced, depending on the required height, by one or more foldable washers, the first and last washers taking the shape of the lower and upper front surfaces of the support sleeve. If the patient's anatomy permits, a support sleeve can also be omitted from the fixation assembly altogether.

[0104] In particular, in this case, the device of the invention is suitable for humans, but it can be adapted for any vertebra, in particular for pets such as horses or dogs. Of course, a person skilled in the art will know how to adjust the dimensions of the elements of the device, in particular according to the length and diameter of the bolt and the rod and therefore according to the dimensions of the clamp and the bearing sleeve and nut.

Claims

1. A vertebral stabilization device, comprising: - At least two bolts (1a; 1b), each having a first threaded portion (1a.1; 1b.1) a second threaded portion (1a.2; 1b.2), the first threaded portion being adapted to engage with a vertebra, the second threaded portion being separated from the first threaded portion by a flange (2); - at least one first connecting rod having two opposite ends for connecting the two threaded portions of the bolt to each other; as well as - at least one first fixing assembly and one second fixing assembly to fix the end of the rod to the bolt, each fixing assembly comprising at least one clip (50) and a nut (80), the clip (50) being engageable on the second threaded portion (1.2) of one of the bolts and being arranged to clamp the end of the rod, the nut (80) having a lower bearing surface and being designed to be tightened on the second threaded portion (1.2) by clamping the clip against the upper surface of the flange of the bolt, each fixing assembly being arranged to produce a ball joint connection between the clip and the second threaded portion.

2. The device according to claim 1, characterized in that The lower bearing surface of the nut (80) and the upper bearing surface of the flange (2) are spherical cap-shaped concave surfaces identical to each other.

3. The device according to claim 1 or 2, characterized in that The clamp (50) of at least the first fixing assembly (F1) comprises a first claw (51) and a second claw (52), wherein the first claw (51) has a complementary spherical cap-shaped protruding outer surface (51.4) to bear on the upper surface of the flange (2), and the second claw (52) has a spherical cap-shaped protruding outer surface (52.4), and the first fixing assembly (F1) comprises a first supporting sleeve (60) of the nut (80) having a complementary lower front surface to bear against the spherical cap-shaped protruding outer surface of the second claw.

4. The device according to claim 3, characterized in that The first bearing sleeve (60) is distinct from the nut (80).

5. The device according to claim 4, characterized in that The first bearing sleeve (60) comprises an upper front surface of a spherical cap-shaped projection, which is complementary to the lower surface of the nut to bear against it.

6. The device according to claim 1 or 2, characterized in that: The clamp (50.2) of at least the first fixing assembly (F2) comprises a first claw (51) and a third claw (53), wherein the first claw (51) has a complementary spherical cap-shaped convex outer surface to bear against the lower surface of the nut (80), and the third claw (53) has a spherical cap-shaped concave outer surface, and the first fixing assembly comprises a second supporting sleeve (70) having a complementary upper front surface (70.2) to bear on the spherical cap-shaped concave outer surface of the third claw.

7. The device according to claim 6, characterized in that The second bearing sleeve (70) has a complementary spherical cap-shaped concave lower front surface (70.1) to bear against the upper surface of the flange (2).

8. A device as claimed in any one of the preceding claims, characterised in that The second component (F3) includes two clamps, namely a lower clamp (50.1) and an upper clamp (50.2), the lower clamp (50.1) including a first claw (51) and a second claw (52), the first claw (51) having a complementary spherical cap-shaped convex outer surface (51.4) to support on the upper surface of the flange (2), the second claw (52) having a spherical cap-shaped convex outer surface, the upper clamp (50.2) including a first claw (51) and a third claw (53), the first claw (51) having a complementary spherical cap-shaped convex outer surface (51.4) to support against the lower surface of the nut (80), and the third claw (53) having a spherical cap-shaped concave outer surface (53.4) complementary to the spherical cap-shaped convex outer surface (52.4) of the second claw (52) to support thereon.

9. The device according to any one of claims 3 to 8, characterized in that Each clamp comprises an elastically deformable portion (55) connecting the jaws (51, 52; 51, 53) so that they can move relative to each other between an open position and a closed position.

10. The device according to any one of claims 3 to 9, characterized in that The first claw (51) is provided with a hole to be engaged on the second threaded portion (1.2) of the bolt (1), the hole comprising a first truncated cone portion and a second cylindrical portion, the first portion having a large cross section opening to the outer surface (51.4) of the first claw (51) and a small cross section combined with the cylindrical cross section of the second portion, the second portion opening to the inner surface (51.3) of the first claw (51).

11. The device according to claims 3 to 10, characterized in that The second claw (52) is provided with a hole to be engaged on the second threaded portion (1.2) of the bolt (1), the hole comprising a first truncated cone portion and a second truncated cone portion, the first portion having a large cross section opening to the outer surface (52.4) of the second claw (52) and a small cross section combined with the small cross section of the second portion, the second portion having a large cross section opening to the inner surface (52.3) of the second claw (52), and a common rotation center being arranged against the small cross sections of the first and second portions.

12. A device as claimed in any one of the preceding claims, characterised in that The flange (2) is removable.

13. A device as claimed in any one of the preceding claims, characterised in that The rod (3) has a constant cross-section over its entire length.

14. A device as claimed in any one of the preceding claims, characterised in that The rod (3) is curved.

15. A device as claimed in any one of the preceding claims, characterised in that The second threaded portion (1.2) of each bolt (1) is provided with an end portion designed to be rotatably connected to a tool for screwing the bolt into the vertebra, and a breaking piece capable of separating the end portion from the second threaded portion by breaking.

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