WO2025045336A1 - Trans-iliosacral pelvic fixation implant - Google Patents

Abstract

The aim of the invention is that of providing an improved pelvic fixation system S^y which can be used in spinal surgery and is effective, simple and easy to use. To this end, the invention relates to a pelvic fixation system S^y which can be used in spinal surgery and comprises:  at least one first element (1) which is intended for trans-iliosacral implantation;  at least one second element (2) which is intended to be implanted in the sacrum; and  at least one third element, preferably an intervertebral link (rod), which belongs to a posterior spinal stabilisation assembly;  the first element (1) being intended to be mechanically connected to the second element (2), which is itself intended to be rigidly connected to the third element; characterised in that  the first element (1) is intended to be implanted first through the iliac bone and the sacrum; and  the first element (1) has at least one hole (14) in which the second element (2) is intended to be fixed once the first element (1) has been implanted. The invention also relates to the first trans-iliosacral element alone, to a sub-assembly of the system S^y, consisting of the first element (1) and the second element (2) or the third element of the system, and to a surgical pelvic fixation kit comprising the fixation system S^y, the sub-assembly or the trans-iliosacral element and an aiming device, which can be used when the first element (1) is screwed into the iliac bone and the sacrum to allow for precise placement of the second element (2) in a hole of the first element (1), and/or at least one awl.

Description

DESCRIPTION

Title: Trans-ilio-sacral pelvic fixation implant

Field of invention

[0001] The invention relates to the general field of spinal surgery, and relates, more particularly, to fixation systems, and more especially for surgery via the posterior approach.

[0002] In particular, the invention relates to a pelvic fixation system usable in spinal surgery comprising a first trans-ilio-sacral element and a second element intended to connect (reversibly or not) the first element to at least one third element, preferably an intervertebral link (e.g. rod), belonging to a posterior spinal stabilization assembly.

[0003] The invention also relates to a surgical pelvic fixation kit comprising this fixation system.

[0004] The invention also relates to a subassembly comprising the first trans-ilio-sacral element and the second or third element of the pelvic fixation system, as well as the first trans-ilio-sacral element as such.

Technological background of the invention

[0005] As shown in the attached figures 1° & 2°, spinal surgery via the posterior approach (spinal osteosynthesis) can consist of the installation of suspended assemblies, such as those each comprising rods (T) fixed to the vertebrae (V), by means of pedicle screws (V ^p ) (hooks or sublaminar links).

[0006] This assembly (TW ^P ) is sometimes fixed to the sacrum (S) and/or to the iliac wings (A') of the pelvis (figure 3), for consolidation purposes, by controlling the correction of deformations in the frontal and sagittal planes. This assembly makes it possible in particular to treat pathologies such as scoliosis or kyphosis and/or to correct pelvic obliquity [imbalance of the pelvis in the frontal plane] and/or pelvic version ("pelvic tilt" angle between the vertical and a line joining the center of the femoral heads to the center of the sacral plateau).

[0007] Connection systems are already known for an iliosacral implant to a posterior spinal osteosynthesis assembly consisting of at least one rod connected to at least one vertebra, using anchoring elements of the pedicle screw or hook type.

[0008] But these known systems are complex and difficult to implement by the surgeon. Objectives of the invention

[0009] The invention aims to achieve at least one of the following objectives, among others:

[0010] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, simple and easy to use.

[0011] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, making it possible to control pelvic obliquity and version.

[0012] An objective of the invention is to provide an improved pelvic fixation system comprising a trans-ilio-sacral screw and usable in spinal surgery, with which the trans-ilio-sacral screw can be implanted percutaneously.

[0013] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, for which the risks of tearing (“pull-out”) are limited, or even eliminated.

[0014] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, for which the risks of mobility of the implanted elements are limited, or even eliminated.

[0015] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, for which the risks of pain for the patient are limited, or even eliminated.

[0016] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, for which the risks of buttock pain are limited or even eliminated.

[0017] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, for which the risks of poor trajectory are limited, or even eliminated.

[0018] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, in which the implanted elements facilitate bone regrowth and rapid colonization by the recipient bone.

[0019] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, for which resection of the iliac bone to avoid any prominence is avoided.

[0020] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, capable of being put in place easily and quickly. [0021] An objective of the invention is to provide an improved pelvic fixation system usable in spinal surgery, reliable, robust, easy to manufacture and economical.

[0022] An objective of the invention is to provide a subassembly of a pelvic fixation system targeted in at least one of the above objectives.

[0023] An objective of the invention is to provide a trans-ilio-sacral element usable in spinal surgery in a pelvic fixation system targeted in at least one of the aforementioned objectives.

[0024] An objective of the invention is to provide a surgical pelvic fixation kit comprising a pelvic fixation system targeted in at least one of the above objectives.

Brief description of the invention

The invention satisfies at least one of the above objectives and relates, according to a first of its aspects, to a pelvic fixation system usable in spinal surgery comprising:

■ at least one first element intended for trans-ilio-sacral implantation;

■ at least one second element intended to be implanted in the sacrum;

■ at least one third element, preferably an intervertebral link (e.g. rod), belonging to a posterior spinal stabilization assembly;

■ the first element being intended to be mechanically connected to the second element, itself intended to be securely connected to the third element; characterized in that the first element is intended to be implanted first through the iliac bone and the sacrum; the first element comprises at least one hole in which the second element is intended to be fixed, once the first element is implanted.

[0025] This system is remarkable in that it is simple and easily implantable in spinal surgery, to remedy spinal deformation pathologies, in particular those involving the pelvis. This system is reliable, stable, effective, and comfortable for the patient. It makes it possible to limit, or even eliminate, pain for the patient. This ease of use makes it possible to limit the duration of surgical procedures.

[0026] In a first preferred embodiment, the position of the second element, relative to the first element, is adjustable. [0027] This position adjustment is understood as an adjustment of the depth of penetration of the second element into a hole in the first element and/or as an adjustment of the position of the second element according to the length of the first element, in the case where the latter comprises several holes for receiving the second element.

[0028] According to the invention, the mechanical connection of the first element with the second element is preferably a screw connection.

[0029] Alternatives to screwing are possible, such as, for example, a connection by pinning; a connection by serration; a connection by adhesion (jamming, deformation, pinching); a connection by keying.

[0030] Screwing and alternatives to screwing can be combined.

[0031] Advantageously, at least one hole of the first element is a through hole. Furthermore, this hole is intended to be at least partially crossed by the second element.

[0032] According to a second embodiment of the system according to the invention, at least one hole of the first element is a non-through blind hole, into which the second element is intended to be inserted.

[0033] In this second embodiment, the mechanical connection of the first element with the ^2nd element is a connection by screwing at the end.

[0034] To this end, the first element advantageously comprises at least one stop intended to cooperate with a part of the second element, when screwing the latter with the first element.

[0035] The second element comprises a head by which the second element is intended to be securely connected to the third element, and, in this second embodiment, the secure connection between the second and third elements contributes to blocking the adjustment of the position of the second element relative to the first element.

[0036] Furthermore, the system according to the invention may have at least one of the following remarkable characteristics:

(i) The second element comprises at least one connecting part with the first element and at least one connecting part to the third element(s), this connecting part being optionally removable relative to the connecting part and in that this connecting part is movable in rotation along at least one axis, preferably several.

(ii) According to a first possibility, the first element comprises at least one tapped hole for receiving the second threaded element and the second element once screwed in, preferably through the first element, forms a single angle, preferably of the order of 90°, relative to the first element.

(iii) According to a second possibility, the first element comprises at least one tapped hole for receiving the second threaded element and the second element can be screwed relative to the first, according to several angles varying at least by +/-5°, preferably by +/- 45°, relative to a direction perpendicular to the axis of the first element.

(iv) The first element comprises several holes (for example successive and/or juxtaposed) offering several possibilities for positioning at least a second element, once the first element is implanted through the iliac bone and the sacrum.

(v) The first element has at least one external thread; this thread preferably comprising at least one part chosen from the group of threads comprising - ideally consisting of - a bone thread, an iso thread, a conical thread, a notched thread, a variable thread, a thread associated with a locking clip, and their combinations.

(vi) The first element is preferably a screw capable of perforating bones.

(vii) Alternatively, the first element could be a pin, particularly a prismatic pin, of any shape, for example, circular, triangular, rectangular, hexagonal...

(viii) The first element and/or the second element is (are) at least partly constituted by at least one biocompatible material, optionally at least partly trabecular and/or porous.

(ix) This biocompatible material is advantageously made up of at least one metallic material, and better still of titanium.

(x) This biocompatible material has at least one of the following remarkable characteristics:

(x.c1) The biocompatible material comprises at least one metal or alloy, in an amount corresponding to - in % by mass and in increasing order of preference -80; 85; 90; 92; 95; 96; 97; 98; 99.

(x.c2) The biocompatible material consists of a plurality of filaments, intertwined and partly contiguous, in which the pores, preferably distributed aperiodically, are formed by the space between these filaments and in which the filaments have a cross-section, preferably substantially circular, the largest dimension of which, preferably the diameter, is between, -in pm and in an increasing order of preference- 10 and 700; 20 and 600; 50 and 500; 100 and 300. (x.c3) The biocompatible material is porous and its porosity is between, - in % by mass and in increasing order of preference -, 50 and 90; 60 and 80; 65 and 75; 68 and 72.

(x.c4) The biocompatible material is porous and the diameter of its pores is between, -in pm and in increasing order of preference-, 500 and 950; 600 and 850; 700 and 800.

(x.c5) The biocompatible, porous material is produced by additive manufacturing (also called three-dimensional printing).

(x.c6) The density of the biocompatible material differs between at least two parts of the first and/or second element.

(xi) After implantation, the second element is intended to be integral with the first element, so as to resist tensile forces along the axis of the second element, greater than or equal to - in Newtons and in increasing order of preference - 500; 550; 600; 650; 700; 750; following a tensile test protocol as defined in ASTM F1798.

(xii) The hole(s) in the first element has (have) a cross-section whose largest dimension is 6 mm +/- 45%.

[0037] The invention also comprises a subassembly comprising the first element of the pelvic fixation system and the second element or the third element of this system.

[0038] According to a second of its aspects, the invention relates to a trans-ilio-sacral element usable in spinal surgery in a pelvic fixation system, in particular the system according to the invention; this system comprising, in addition to at least one trans-ilio-sacral element forming a first element, at least one second element intended to be implanted in the sacrum, and at least one third element, preferably an intervertebral link (e.g. rod), belonging to a posterior spinal stabilization assembly; the second element being intended to connect the first element to the third element.

In this system: the first element is intended to be implanted first through the iliac bone and the sacrum; the first element comprises at least one hole in which the second element is intended to be fixed, once the first element is implanted.

[0039] According to a third of its aspects, the invention relates to a surgical pelvic fixation kit characterized in that it comprises a pelvic fixation system usable in spinal surgery according to the invention and at least a third element, preferably an intervertebral link (eg rod), belonging to a posterior spinal stabilization assembly.

[0040] Advantageously, the first element is a screw and the kit comprises: a sighting device, preferably a frame, capable of being implemented during the implantation, preferably by screwing, of the first element in the iliac bone and the sacrum, to allow the precise placement of the second element in a hole in the first element; and/or at least one perforator intended to make an opening in the sacrum to receive the second element and allow the visualization of the first element introduced, preferably by screwing into the iliac bone and the sacrum and thus ensure the precise placement of the second element in a hole in the first element.

Brief description of the drawings

[0041] This description is made with reference to the appended figures illustrating non-limiting exemplary embodiments, and in which:

Fig. 1

[0042] [Fig. 1] is a perspective view of a portion, above the sacrum, of a spinal column showing a stage of a posterior stabilization assembly spinal surgery, in which one of the two intervertebral rods T of the assembly is fixed to the vertebrae V, by means of pedicle screws V ^p .

Fig. 2

[0043] [Fig. 2] is a perspective view of a portion, including the sacrum, of a spinal column showing a step of a posterior stabilization assembly spinal surgery, in which the two intervertebral rods T of the assembly are fixed to the vertebrae V by means of pedicle screws V ^p , after the step shown in Fig. 1 .

Fig. 3

[0044] [Fig. 3] is a perspective view of a pelvis (sacrum S & iliac wings A').

Fig. 4

[0045] [Fig. 4] is a perspective view of the fixation system S ^y according to the invention in situ, the first element 1 of which is placed through the ilium A' and the sacrum S, the second element 2 of which is placed in the sacrum S and the third element (intervertebral rod 3) of which is connected to the second element 2, to form a posterior stabilization assembly. Fig. 5

[0046] [Fig. 5] is a perspective view of the first element 1 (trans-ilio-sacral screw VTIS) of the fixation system S ^y according to a first embodiment of the invention, crossed by the second element 2 (sacral screw VS) of this system S ^y .

Fig. 6

[0047] [Fig. 6] is a front view of the screws 1,2 of Fig. 5.

Fig. 7

[0048] [Fig. 7] is a side elevation view from the right of the screws 1, 2 of Figure 5.

Fig. 8

[0049] [Fig. 8] is a side elevation view from the left of the screws 1, 2 of Fig. 5.

Fig. 9

[0050] [Fig. 9] is a perspective view from above of the screws 1,2 of Fig. 5.

Fig. 10

[0051] [Fig. 10] is a partial longitudinal sectional view along the median longitudinal plane of the VTIS 1 corresponding to the section line X-X of Figure 6.

Fig. 11

[0052] [Fig. 11] is a perspective view of a system S ^y according to the invention according to the second embodiment of the invention comprising a trans-ilio-sacral screw T, the holes 14' of which are blind and a sacral screw 2', capable of cooperating with one of these blind holes 14'.

Fig. 12

[0053] [Fig. 12] is another perspective view of a variant V1 of the first embodiment of the fixation system S ^y according to the invention. In this variant V1 , the first element 1” (trans-ilio-sacral screw VTIS) is vertical (in the representation of the figures), and crossed by the second element 2” (sacral screw VS) which is horizontal (in the representation of the figures).

Fig. 13

[0054] [Fig. 13] comprises, respectively, from left to right, a left side elevation view of the first 1” element (VTIS screw) of the system shown in Figure 12, a middle view in longitudinal section of the 1” VTIS screw along the section line CC of the left view and a right view of the system in section, along the same plane as the view from the middle, this right view showing the VS 2” screw screwed into the VTIS 1” screw, passing through the latter and forming with it a fixed angle of approximately 90°.

Fig. 14

[0055] [Fig. 14] includes views of a variant V2 of the first embodiment of the fixing system S ^y according to the invention, according to the same views as FIG. 13, and in which the right-hand view is a sectional view CC of the system S ^y , according to the same plane as the middle view, this right-hand view showing the screw VS 2* screwed into the screw VTIS 1*, passing through the latter and having an angular clearance D , relative to the axis YY of the screw VTIS 1*, in the sectional plane CC corresponding to the median longitudinal plane of the screw VTIS 1* which includes the axis XX of the screw VS 2*.

Fig. 15

[0056] [Fig. 15] is a front view of a ^first possible embodiment of a sighting device

30 ¹ useful for the surgical implantation of a fixation system S ^y according to the invention.

Fig. 16

[0057] [Fig. 16] is a front perspective view of the aiming device 30 ¹ of FIG. 15 as it is used in situ (ilium-sacrum-lumbar) during the surgical implantation of a fixation system S ^y according to the invention.

Fig. 17

[0058] [Fig. 17] is a side perspective view of the aiming device 30 ¹ of FIG. 15, as used in situ (ilium A'-sacrum S-lumbar) during the surgical implantation of a fixation system S ^y according to the invention.

Fig. 18

[0059] [Fig. 18] is a perspective view from below of the aiming device 30 ¹ of FIG. 15 as it is used in situ (ilium A' -sacrum S- lumbar) during the surgical implantation of a fixation system S ^y according to the invention.

Fig. 19

[0060] Figure 19 is a front view of a ^2nd possible embodiment of the sighting device.

30 ² useful for the surgical implantation of a fixation system S ^y according to the invention.

Fig. 20

[0061] [Fig. 20] is a front perspective view of the aiming device 30 ² of FIG. 19, as used in situ (ilium A'-sacrum S-lumbar) during the surgical implantation of a fixation system S ^y according to the invention. Fig. 21

[0062] [Fig. 21] is a side perspective view of the aiming device 30 ² of FIG. 19 as used in situ (ilium A'-sacrum S-lumbar) during surgical implantation of a fixation system S ^y according to the invention.

Fig. 22

[0063] [Fig. 22] is a perspective view from below of the aiming device 30 ² of FIG. 19 as it is used in situ (ilium A'-sacrum S-lumbar) during the surgical implantation of a fixation system S ^y according to the invention.

Definitions

[0064] The following definitions are given, as examples, to facilitate the interpretation of this disclosure:

* any singular can designate a plural and vice versa.

* “substantially”; “approximately”; “of the order of”: +/- 10% of the relevant unit of measurement of the international system.

* “upper/lower” “top/bottom” “vertical/horizontal” are defined in relation to the figures and the body of the patient receiving the fixation system according to the invention.

* “ISO thread or thread”: may refer to an ISO metric thread with triangular thread NF ISO 724 cylindrical profile. NF EN ISO 228-1; thread with conical or cylindrical profile NF EN 10226-1, EN 10226, ISO 228.

Detailed description of the invention

[0065] In the exemplary embodiments shown in FIGS. 4 to 15, the pelvic fixation system S ^y according to the invention comprises:

■ a first element consisting of a trans-ilio-sacral screw (VTIS) which is intended to be implanted first in the patient, by the surgeon, so that this first element crosses an iliac wing A' to come and lodge in the sacrum S;

■ a second element 2 formed by a screw secured to the rod 3 and intended to be screwed through the trans-ilio-sacral screw 1, so as to be able to adjust the position of the screw 2 relative to this trans-ilio-sacral screw 1; ■ and a third element, in this case an intervertebral rod 3, belonging to a posterior spinal stabilization assembly possibly comprising another intervertebral rod, this rod or these two rods being fixed to the vertebrae (V), for example by means of pedicle screws (V ^p ) as shown in figures 1 & 2.

[0066] In a first embodiment, the first trans-ilio-sacral element or screw 1 comprises a head 10 located at one of the ends of a threaded body 11 (external thread 11 ^fe ) the other end of which is a point 12 which gives this screw the ability to perforate bones.

[0067] This body 11 has four through holes 14, tapped and juxtaposed. The axis of each of the holes 14 is substantially perpendicular to the axis of the trans-ilio-sacral screw 1. Each hole 14 has an upper opening 15 and a lower opening 16. These 4 holes 14 are as many possibilities for positioning the (sacral) screw 2 relative to the trans-ilio-sacral screw 1. This arrangement can facilitate the securing of the fixation system S ^y according to the invention, relative to the posterior spinal stabilization assembly.

[0068] The (sacred) screw 2 is essentially composed of a threaded body 21 and a head 22.

[0069] As shown in particular in figures 5, 6, 9, 10, 12, 13 (right view) & 14 (right view), the female internal thread 14 ^fi of the holes 14 is suitable for cooperating with the male external thread 21 ^fe of the body 21 of the (sacred) screw 2, to generate a mechanical connection by screwing between the first element 1 and the second element 2, which then form a cross-shaped assembly.

[0070] According to a remarkable characteristic of the invention, the female internal thread 14 ^fi of the holes 14 is designed to allow the engagement of the body 21 of the screw 2, both through the upper opening 15 and through the lower opening 16 of the hole 14. The female internal thread 14 ^fi extends from the upper opening 15 to the lower opening 16.

[0071] Thus assembled and implanted in situ, the two screws 1 and 2 form an inseparable unit: the trans-ilio-sacral screw 1 can no longer rotate or translate. The same applies to screw 2. The latter is first screwed into screw 1 implanted through the ilium and into the sacrum. The position of this screw 2 (or insertion depth) relative to screw 1 is thus adjustable. This allows the surgeon to correctly position the head 22 of this screw 2 relative to the third element of the system, namely the intervertebral rod 3, before fixing them to each other. The system is thus locked in an optimal position to remedy the pathology from which the patient suffers. [0072] In the ^first embodiment, the cross section of the holes 14 is substantially circular and of constant diameter: for example approximately 6 mm +/- 1.5 mm, for the screw thread.

[0073] As shown in FIGS. 5, 6, 9 & 11, each through hole 14 opens at its two ends into an upper 17 and lower 18 clearance, respectively, provided in the trans-ilio-sacral screw 1. Each clearance 17, 18 comprises a flat 19 parallel to the median longitudinal plane of the screw 1 and from which rise two opposite flanges 19 ¹ , 19 ² each inscribed in a diametrical plane of the screw 1 and extending to the threaded outer face of the screw 1. Each upper 15 and lower 16 opening of a hole 14 is in the plane of the flat 19.

[0074] The external thread 11 ^fe of the body 11 of the screw 1 is for example a bone thread and/or an ISO thread.

[0075] The head 10 of the trans-ilio-sacral screw 1 comprises on its external face a hexalobe screwing cavity 10 ¹ in this embodiment example. This head also comprises a groove 10 ² (figure 7) extending inwards and connecting the head 10 to the body 11 of the screw 1.

[0076] The head 10 of the trans iliosacral screw 1 may be polyaxial relative to the body 11 of the screw 1, in order to best adapt to the anatomy of the iliac bone.

[0077] As shown in Figures 5 to 9, the screw 2 (sacral) may be a pedicle screw with a polyaxial head 22. Pedicle screws are commonly used in spinal surgery. This polyaxial head 22 is articulated on a 21° ball joint provided on the head of the threaded body 21 of the screw 2.

[0078] The clearances 17 & 18, the flat 19, the edges 19 ¹ , 19 ² , are absent from the variants V1 and V2 of the figures, respectively, 12 & 13, and, 14.

[0079] For variant V1 of figures 12 & 13, the references used to designate all the parts and parts of parts of the fixing system S ^y according to the invention are the same as those of figures 4 to 10 with the superscript (”).

[0080] As for the ^1st embodiment, the cross-section of the 14” holes of the 1” screw in the variant V1 of figures 12 & 13, is substantially circular and of constant diameter: for example approximately 6 mm +/- 1.5 mm, for the screw pitch.

[0081] For variant V2 of figure 4, the references used to designate all the parts and parts of parts of the fixing system S ^y according to the invention are the same as those of figures 4 to 10 with the superscript (*).

[0082] According to the variant V2 appearing in Figure 14, the cross-section of the holes 14* of the screw 1* can be oblong, so that the (sacred) screw 2* can have a clearance angular D in the median longitudinal plane of the VTIS 1 screw with axis YY including the axis XX of this (sacral) screw 2*, relative to the axis of the VTIS 1* screw. The angular movement D corresponds to an angle 2a, with a having a value of at least 5°, for example of the order of 30°, on either side of the perpendicular PP to the YY axis of the screw 1*. This additional degree of freedom relative to the translation of the (sacral) screw 2* relative to the trans-ilio-sacral screw 1*, is likely to simplify the surgeon's task when setting up the fixation system S ^y on the patient.

[0083] In a second embodiment shown in FIG. 11, the trans-ilio-sacral screw T formed by a head 10' and a screw body 1T with a thread 1T ^fe , comprises blind non-through holes 14'. This screw T is associated in the fixation system according to the invention, with a screw 2' (sacral) constituted by a threaded body 2T and a polyaxial head 22', of the type equipping pedicle screws such as those described above. The 2T threaded body and the 22' polyaxial head are identical to those bearing the internal references 21 and 22 and described above, with the difference that the 2T threaded body has, on the one hand, a length corresponding substantially to the depth of the non-through blind holes 14' of the body of the 1 T screw of the screw 1, and, on the other hand, an ISO type thread.

[0084] The internal thread of the blind non-through holes 14' of the trans-ilio-sacral screw T is suitable for cooperating with the external thread 21 ^fe ' of the body 2T of the (sacral) screw 2', to secure the screws T and 2'.

[0085] The bottoms of the non-through blind holes 14’ of the trans-ilio-sacral screw T, each form an end-of-travel stop, intended to come into contact with the free end of the screw body 2T of the screw 2’, and thus to block the translational travel of the latter.

[0086] Alternatively, this blocking of the translational travel of the screw 2’ can be obtained by means of an end-of-travel stop located on the neck of the (sacred) screw 2’ and designed to come into contact with the screw body 1 T of the screw T. In this alternative, the holes 14’ are through holes. However, it is not excluded to provide blind non-through holes 14’, the bottoms of which may or may not be stops possibly supplementing the action of the end-of-travel stop of the neck of the screw 2’.

[0087] The end-of-travel lock, whatever it may be, determines the position, relative to the trans-ilio-sacral T screw, in which the sacral screw 2’ must be brought to ensure the locking of the connection of the second element of the system with the first element.

[0088] This locking of the connection of the second element of the fixing system according to the invention, with the first element can also be achieved by other means, not shown in the figures, such as conical wedging, or the implementation of a nut/lock nut screwed onto the sacred screw. [0089] According to another possible embodiment, the head 22,22' and the body 21,2T of the sacred screw 2,2' can be separated and assembled. Thus, the body 21,2T can be, initially, secured by screwing with the body 11 of the screw 1, the head 22,22' being mounted on the head 21°,21'° of the body 21,2T of the screw 2 secured to the body 11 of the screw 1.

[0090] According to another possible embodiment, the head 22,22’ of the sacral screw 2, 2’, 2”, 2*, (for example pedicle) may be uniplanar or monoaxial, that is to say with a blocking of the polyaxiality for example in the sagittal plane, or even partially polyaxial.

[0091] The 1,1’,1”,1*, trans-ilio-sacral screw and the 2, 2’, 2”, 2*, sacral screw may be made of a biocompatible material, in particular metal such as titanium or a metal alloy such as chromium/cobalt or titanium/aluminum/vanadium (e.g. Ti6AI4V or TA6V). Titanium is particularly preferred.

[0092] It is also advantageous that at least part of the constituent material, at least of the first element of the fixing system S ^y according to the invention, is porous and trabecular. The porosity is, for example, of the order of 70% by mass. The pores of this material are substantially circular with a diameter of between 700 and 800 μm. The pores can be defined by intersecting and partly contiguous filaments, for example of circular cross-section with a diameter of between 100 and 300 μm.

[0093] The 1,1’, 1”,1*, trans-ilio-sacral screw and the 2,2’,2”,2*, sacral screw can be manufactured by conventional machining or by additive manufacturing (otherwise known as three-dimensional printing).

[0094] "Additive manufacturing" refers to manufacturing processes involving the addition of material, most often computer-assisted. It is defined by the ASTM ("American Society for Testing and Materials") as the process of shaping a part by adding material, by stacking successive layers, as opposed to processes involving the removal of material, such as machining. Such a technology is commonly called three-dimensional printing (3D printing). An example of 3D printing is laser sintering, such as selective laser sintering (SLS), direct metal laser sintering (DMLS) or electron beam melting (EBM). As an example of EBM, we can cite Ti-LIFE TECHNOLOGY from the company SPINEART®.

[0095] The intervertebral rod 3 is, for example, made of titanium alloy or cobalt-chromium alloy. It may be an intervertebral rod marketed by Spineart® under the name Perla® TL straight Rod.

[0096] The system S ^y according to the invention is designed to allow the surgeon: -> to implant the first element, namely the 1,1',1”,1* trans-ilio-sacral screw, through the ilium and into the sacrum, ensuring that the axis of the holes 14, 14', 14”, 14* of the 1, 1',1”,1* screws is substantially parallel to the horizontal plane; to make a notch in the S1 vertebra using a perforator, to engage a trans-iliosacral screw 1 ,1',1”,1* through the notch, adjusting the orientation of the trans-iliosacral screw 1 , 1', 1 ”, 1*, in order to visualize the hole 14, 14', 14”, 14*, or one of the holes to insert the sacral screw 2, 2', 2”, 2*, through the screw 1 , 1', 1 ”, 1*;

->to adjust the depth position of the sacral screw 2, 2’, 2”, 2*, relative to the trans-ilio-sacral screw 1, 1’, 1”, 1*; to fix the intervertebral rod 3 to the head 22,22’ of the sacral screw 2, 2’, 2”, 2*, to contribute to blocking the position of the sacral screw 2, 2’, 2”, 2* relative to the trans-ilio-sacral screw 1,1’,1”,1*.

[0097] According to an advantageous embodiment, the system S ^y according to the invention is associated with a sighting device, such as that shown in the attached figures 15 to 22.

[0098] Figure 15 represents a ^first possibility of execution of the aiming device 30 ¹ and Figures 16 to 18 illustrate the implementation of the latter for the implantation of the pelvic fixation system S ^y according to the invention.

[0099] Figure 19 represents a ^2nd possibility of execution of the aiming device 30 ² and Figures 20 to 22 illustrate the implementation of the latter for the implantation of the pelvic fixation system S ^y according to the invention.

[0100] The aiming device 30 ¹ , 30 ² is constituted by a frame with four segments contained in the same plane, namely:

* a longitudinal segment 31 ¹ , 31 ² intended, during the implantation of the pelvic fixation system S ^y according to the invention, to be positioned parallel to the axis YY of the screw VTIS 1 ,1',1”,1*;

* a transverse segment 32 ¹ , 32 ² , preferably perpendicular to the longitudinal segment 31 ¹ , 31 ² ;

* a transverse segment 33 ¹ ,33 ² for sacral aiming, opposite the transverse segment 32 ¹ ,32 ² and intended, during the surgical procedure, to be positioned in the axis along which the sacral screw 2, 2', 2”, 2* must be inserted;

* and a longitudinal sacroiliac segment 34 ¹ ,34 ² , integral with the end of the transverse segment 32 ¹ ,32 ² opposite that connected to the longitudinal segment 31 ¹ ,31 ² , preferably perpendicular to the transverse segment 32 ¹ ,32 ² , and intended, during the intervention surgical, to be positioned in the axis along which the VTIS 1,1',1”,1* must be placed.

[0101] The transverse sacral aiming segment 33 ¹ , 33 ² is, advantageously, a guide tube allowing the passage of a part (in particular the rod) of a tool intended to contribute to the implantation of the sacral screw 2, 2', 2”, 2*, in the sacrum in the direction chosen by the surgeon.

[0102] This tool can be, for example, a square tip, an osteotome, a tap or a screwdriver.

[0103] In the ^1st possibility of execution of the aiming device 30 ¹ , the transverse segment 33 ¹ , 33 ² of the sacred aiming is substantially perpendicular to the longitudinal segment 31 ¹ , 31 ² .

[0104] In the ^2nd possibility of execution of the aiming device 30 ² , the transverse segment 33 ¹ , 33 ² of the sacred aiming forms a given angle A ² (Figure 19), less than 90°, with the longitudinal segment 31 ¹ , 31 ² .

[0105] The transverse segment 33 ¹ , 33 ² of the sacred sight is either fixed or capable of pivoting relative to the longitudinal segment 31 ¹ , 31 ² , in the plane of the frame or in a plane parallel to it, so as to be able to give the angle A ² different values.

[0106] The position of the longitudinal segment 31 ¹ , 31 ² is advantageously adjustable and lockable in translation, relative to the transverse segment 32 ¹ , 32 ² , parallel to the ilio-sacral direction of the longitudinal sacro-iliac segment 34 ¹ , 34 ² .

[0107] It is possible to define different lockable positions of this longitudinal segment 31 ¹ , 31 ² , one of these positions being intended to correspond to the alignment of the axis of the tubular segment 33 ¹ , 33 ² of the sacral sight with the axis of a hole 14, 14', 14”, 14*, of the screw VTIS 1 , 1', 1”, 1*.

[0108] The longitudinal sacroiliac tubular segment 34 ¹ , 34 ² is advantageously a guide tube allowing the passage of a part (in particular the rod) of a tool intended to contribute to the implantation of the VTIS screw 1 , 1', 1 ”, 1*, through the ilium and the sacrum in the direction chosen by the surgeon.

[0109] This tool may be, for example, a square tip, an osteotome, a tap or, as shown in the figures, a screwdriver 35 ¹ , 35 ² .

[0110] The pelvic fixation system S ^y according to the invention and the aiming device 30 ¹ , 30 ² are designed to allow the surgeon: to implant the first element, namely the trans-ilio-sacral screw 1 , 1', 1”, 1*, through the ilium and into the sacrum, ensuring that the axis of the holes 14, 14', 14”, 14*, of the screws 1, T,1”,1*, is substantially parallel to the horizontal plane and by implementing the aiming frame 30 and the screwdriver 37, so that the sacral screw 2, 2', 2”, 2*, can be guided in a hole 14, 14', 14”, 14*, of the trans-ilio-sacral screw 1, 1',1”,1*;

->to adjust the position of the sacral screw 2, 2’, 2”, 2*, in relation to the trans-ilio-sacral screw 1,1’,1”,1*;

-> to fix the intervertebral rod 3 to the head 22, 22’, 22”, 22*, of the sacral screw 2, 2’, 2”, 2*, to block the translational position of the sacral screw 2, 2’, 2”, 2*, relative to the trans-ilio-sacral screw 1, 1’, 1”, 1*.

[0111] The system S ^y according to the invention secures the stable, precise and robust fixation of the pelvic anchor (first and second elements) to the third element, an intervertebral rod of a posterior spinal stabilization assembly. In doing so, the correction of spinal deformation pathologies, in particular those involving the pelvis, is significantly optimized, by minimizing pain for the patient and allowing him to recover as quickly as possible a better state of health with regard to the spine.

[0112] The pelvic fixation surgical kit according to the invention comprises:

* the pelvic ^fixation system described above (and/or the first and second elements and/or the first and third elements);

* and: a sighting device, for example a sighting frame, capable of being implemented when screwing the first element into the iliac bone and the sacrum, to allow the precise placement of the second element in a hole in the first element; and/or at least one perforator intended to make an opening in the sacrum to receive the second element and allow the visualization of the first element introduced by screwing into the iliac bone and the sacrum and thus ensure the precise placement of the second element in a hole in the first element.

[0113] The perforator is, for example, a square point or an osteotome.

Claims

Claims [Claim 1] Pelvic fixation system S ^y usable in spinal surgery comprising: ■ at least one first element (1, 1’,1”,1*) intended for trans-ilio-sacral implantation; ■ at least one second element (2, 2’, 2”, 2*) intended to be implanted in the sacrum; ■ at least one third element (3), preferably an intervertebral link, belonging to a posterior spinal stabilization assembly; ■ the first element (1,1’,1”,1*) being intended to be mechanically connected to the second element (2, 2’, 2”, 2*), itself intended to be securely connected to the third element (3); characterized in that the first element (1, 1’,1”,1*) is intended to be implanted first through the iliac bone and the sacrum; the first element (1, 1’, 1”,1*) comprises at least one hole (14, 14’, 14”, 14*) in which the second element (2, 2’, 2”, 2*) is intended to be fixed, once the first element (1, 1’,1”, 1*) has been implanted. [Claim 2] ^Fixing system according to claim 1 characterized in that the position of the second element (2, 2', 2”, 2*) relative to the first element (1, 1', 1”, 1*) is adjustable. [Claim 3] ^Fastening system according to claim 1 or 2, characterized in that the mechanical connection of the first element (1, 1', 1”, 1*) with the second element (2, 2', 2”, 2*) is a screw connection. [Claim 4] Fastening system S ^y according to at least one of the preceding claims, characterized in that at least one hole (14, 14', 14”, 14*) of the first element (1, 1', 1”, 1*) is through and in that this hole (14, 14', 14”, 14*) is intended to be at least partially crossed by the second element (2, 2', 2”, 2*). [Claim 5] Fastening system S ^y according to at least one of the preceding claims, characterized in that the first element (1, 1', 1”, 1*) comprises at least one tapped hole (14, 14', 14”, 14*) for receiving the threaded second element (2, 2', 2”, 2*) and in that the second element (2, 2', 2”, 2*) once screwed into, preferably through, the first element (1, 1 1 ”, 1*), forms a single angle, preferably of the order of 90°, with respect to the first element (1, 1', 1 ”, 1*). [Claim 6] Fastening system S ^y according to at least one of the preceding claims, characterized in that the first element (1, 1', 1", 1*) comprises at least one tapped hole (14, 14', 14", 14*) for receiving the second threaded element (2, 2', 2", 2*) and in that the second element (2, 2', 2", 2*) can be screwed relative to the first element (1, 1', 1", 1*), according to several angles varying at least by +/-5°, preferably by +/-45°, relative to a direction perpendicular to the axis of the first element (1, 1', 1", 1*). [Claim 7] Fixing system S ^y according to at least one of the preceding claims, characterized in that the first element (1, 1', 1”, 1*) comprises several holes (14, 14', 14”, 14*) offering several possibilities for positioning at least one second element (2, 2', 2”, 2*), once the first element (1, 1', 1”, 1*) is implanted through the iliac bone and the sacrum. [Claim 8] Fastening system S ^y according to at least one of claims 1 to 3, 5 to 7, characterized in that at least one hole (14') of the first element (1, 1', 1”, 1*) is a blind non-through hole (14'), into which the second element (2, 2', 2”, 2*) is intended to be inserted. [Claim 9] ^Fastening system according to claim 8 characterized in that the mechanical connection of the first element (1, 1', 1”, 1*) with the second element (2, 2', 2”, 2*) is a connection by screwing in abutment. [Claim 10] Fixing system S ^y according to at least one of the preceding claims, characterized in that the first element (1, 1', 1”, 1*) is capable of perforating bones. [Claim 11] Fastening system S ^y according to at least one of the preceding claims, characterized in that the second element (2, 2', 2”, 2*) comprises at least one connecting part (21, 2T, 21”, 21*) with the first element (1, 1', 1”, 1*) and at least one connecting part (22, 22', 22”, 22*) to the third element(s) (3), this connecting part (22, 22', 22”, 22*) being optionally removable relative to the connecting part and in that this connection part (22, 22', 22”, 22*) is movable in rotation along at least one axis, preferably several. [Claim 12] Subassembly of the S ^y fixing system according to at least one of the preceding claims, characterized in that it is composed of the first element (1, 1', 1", 1*) of the S ^y system and of the second element (2, 2', 2", 2*) or of the third element of the S ^y system. [Claim 13] Trans-ilio-sacral element usable in spinal surgery in a pelvic fixation system S ^y , in particular according to at least one of claims 1 to 12, this system S ^y comprising, in addition to at least one trans-ilio-sacral element forming a first element (1, 1', 1”, 1*), at least one second element (2, 2', 2”, 2*) intended to be implanted in the sacrum and at least one third element, preferably an intervertebral link (eg rod), belonging to a posterior spinal stabilization assembly, the second element (2, 2', 2”, 2*) being intended to connect the first element to the third element; characterized in that the first element (1, 1', 1”, 1*) is intended to be implanted first through the iliac bone and the sacrum; the first element (1, 1', 1”, 1*) comprises at least one hole in which the second element (2, 2', 2”, 2*) is intended to be fixed, once the first element (1, 1', 1”, 1*) is implanted. [Claim 14] Surgical pelvic fixation kit characterized in that it comprises: ->the S ^y fixation system according to at least one of claims 1 to 11, the subassembly according to claim 12, or the trans-ilio-sacral element according to claim 13; a targeting device (30 ¹ ,30 ² ), preferably a frame, capable of being implemented during the implantation, preferably by screwing, of the first element (1 , 1', 1 ”,1*) in the iliac bone and the sacrum, to allow the precise positioning of the second element (2, 2', 2”, 2*) in a hole (14, 14', 14”, 14*) of the first element (1 , 1', 1 ”, 1*); and/or at least one perforator intended to make an opening in the sacrum to receive the second element (2, 2', 2”, 2*) and to allow the visualization of the first element (1, 1', 1”, 1*) preferably introduced by screwing, into the iliac bone and the sacrum and thus ensure the precise positioning of the second element (2, 2', 2”, 2*) in a hole (14, 14', 14”, 14*) of the first element (1, 1', 1”, 1*).