PNEUMATIC DEVICE PFLRÑ POSTERIOR VERTEBRAL QSTEOSINTESISMEGIORIR DESCRIPTIVEThis invention relates to an anchoring device for posterior vertebral osteosynthesis. The technical field of the invention is the domain of the manufacture of irnplan + is of osteosynthesis intended for the vertebral column of the human being or of an animal. When it is desirable to stabilize or fix two or more vertebrae to one another and / or reduce deformations of the spine (such as kyphosis or scoliosis), the use of longitudinal metal devices that connect several vertebrae is known, for example with plates or rods, and on which are anchored other metal fasteners such as screws, Several requests have been made for paten + e, in pair + Leular for different systems of vertebral osteosynthesis, + ales co or for example Application No. FR 2 716 794, published on September 8, 1995 and requested by the American company Sofa or (inventor: Mr. Steib) for a "Connector for + he implementation of rachidian osteosynt esis i tended for lumbar or sacral or iliosacral fixing "or Application No. FR 2 712 486 published on May 24, 1995 by Messrs. Breslav, Cato, etc ... of an" Intervertebral prosthesis "or the Solici + ud No. FR 2 697 874, published on May 13, 1994 by the Fabri Society cation of Orthopedic Material (inventor: Mr. Contrel) entitled "ñ connecting device for long thm element and for a support for this element". Other prior applications may also be mentioned, such as Application No. FR 2 672 202 published August 7, 1992, by the Safir Company (inventors, Mr. Graf et al.) For a "Surgical bone plant, notably for an mterverte ral. stabilizer "or Application No. FR 2 651 992, published on March 22, 1991 by the Orthopedic Material Manufacturing Company (inventor: Mr. Lauram) for" end irnplant for anterior dorso-lumbar rachidian osteosynthesis, intended for The correction of cyphosis ". All these systems, like many others, too numerous to mention here, use essentially for their fixation on the vertebrae, screws that require screwing on the bony parts, which is somewhat delicate and is in any case at the expense of bone fragility. There are also systems based on hooks or belts around the regions of the fin, spinal, transversal or articular (but never isthmic) of each vertebra, but these regions, which are considered to be somewhat fragile, do not allow by themselves apply great moments of correction torsion. Therefore the problem posed is to be able to produce SLSternae of vertebral osteosynthesis while using anchoring devices that are not screwed to the vertebrae but are fixed in a sufficiently rigid manner to allow them to apply the great moments of correction torsion without weakening or risk the damage to said vertebrae. A solution to the proposed problem is an anchoring device for posterior vertebral osteo-synthesis comprising at least 4 fixing points, each constituted by a hook, the hooks being opposite one another, two in two, along two axes perpendicular XXV ZZ 'and each pair of hooks mounted in this manner, forming a clamp, which is considered to be along the lateral axis XX' referred to as isthmic and the other axial ZZ 'referred to as laminar; such hooks are fixed rigidly to supports connecting them to one and the same central body, preferably a single solid block and the ends of these hooks are at least 5 rn wide. The central body receives a fixing means which immobilizes any means of connection at least with another anchoring device, such as at least one rod; the fixing means for this can then be a collar that is seated thereon and immobilizes it in said central body by holding it in the manner of a clamp. In a preferred embodimenteach support of each of said hooks or each pair defined above is mounted slidably with respect to said central body and is usable along the axes ZZ '/ XX' which allows them to be closer to each other or further separated, said hook supports can slide from said central body, being able to move from the ediante any rnodium that goes through said central body, such as, for example, locking shafts. Such a system treats the proposed problem very well, allowing in effect an anchoring in each posterior arch of the vertebra, as shown in figures 4 and 5.; the two hooks referred to as isthmics, as defined above, opposed later along the horizontal ee XX 'of the device once in position, when the person involved is in the upright position, can be hooked on the right and left isthmic regions of the vertebra in the back of the foramina, which are the conjugation orifices through which the spinal nerves emerge, something that has not been done until the present time; the other two hooks that are axially opposed along the perpendicular axis ZZ ', therefore vertical once in position, are hooked on the middle part of the upper and lower edges of the fins of the same vertebra; these hook assemblies thus form two perpendicular handles, fixed rigidly by a common component that crosses over the supports. In a particular embodiment, the supports of the hooks referred to as isthmus, arranged laterally on the isthmic regions are constituted by two concentric cylindrical axes sliding one inside the other, of the circular cross section and allowing the rotation of said hooks around the its locking ee thus providing perfect adaptation of the anchor to the morphology of the vertebra. The supports of the hooks referred to as laminar, arranged axially to vertically in order to catch on the upper and lower edges of the fins of the same vertebra, can preferably be made of two cylindrical but not circular guides that slide and fit one inside. of the other, and which work together with a rail of the central body that avoids its rotation with respect to its locking axis in order to immobilize said central body on the vertebra. The sliding supports of each hook make it possible to match the length with the collar they form to the size of the vertebra on which it is desirable to anchor, without requiring any operation on the bone of the vertebra and thus to avoid any weakening thereof. , while providing, by means of a tetrapod thus constituted, a perfect anchor that allows the attraction and large torsional forces. The hooks that exist today, such as those mentioned above, are always narrow, possibly pointed or rounded at their end and are never supported on the vertical isthmus, nor are they combined with the other hooks arranged on the midline of the vertebral fins superior and inferior .. The result is a new device for the anchoring of a posterior vertebral osteosynthesis, which constitutes this invention, whose advantages different from those mentioned above could be mentioned but sufficient of which have already been pointed out to prove the seriousness and the interest of the ism. The description and the following figures represent an example of a modality of the invention which is not limiting in any way: other modalities are possible, within the context of the sphere of application and the extension of this invention, in particular changing the form of the various hook supports and the central body supporting said supports and the means of connection between the successive anchoring devices. Figure 1 represents a device according to the invention, in an exploded perspective view, each element being disassembled. Figure 2 is a perspective view of the same device as Figure 1 but armed. Figure 3 is a view of one of the devices of the preceding figures in a cranial view, therefore from above once placed in position. Figure 4 is a straight side view of the same device anchored on the vertebra. Figure 5 is a schematic view of the individual hooks and their support placed in position, according to Figure 4.
The anchoring device for posterior vertebral osteosynthesis on a vertebra 13 comprises, according to the invention, at least 4 fixing points, each constituted by a hook 4,5,6,7, the hooks being opposite one another, 2 in 2, along two perpendicular axes, XX 'horizontal once put into position in case the person involved is in an upright position and ZZ' vertical with each pair thus constituted, forming a clamp. The ends of said hooks 4,5,6,7 are sufficiently wide to provide an extension of the support and the clamping force on the parts of the vertebra, while avoiding any rotation of the device, thus limiting its possible displacement with respect to said vertebra on which it is anchored. For this, the width of the ends of said hooks can be, for example, by the monkeys of 5 rn on the surface in which they press on the parts of the vertebra that receive said hooks. As indicated above, they are rigidly fixed to the supports connecting them to one and the same central body 1, preferably a single solid block, the supports slide and are adjustable with respect to the block along the e is respectively ZZ ' for vertical torque 4.5 and XX 'for horizontal torque 6.7 allowing these hooks to move closer together or move more apart from each other.
Regarding the lateral hooks 6,7 referred to as isthmus hooks, their supports can be two cylindrical and concentric axes 8,9, one of which can be hollowed out to allow the other male axis 8 to be inserted, sliding one inside of and with respect to another, until they are blocked by their respective ends that are formed as heads, said lateral hooks 6,7 on the outside of the isthmic regions 19 at the back of the foramina 18 of the vertebra 13; the circular cross section of said axes allowing their rotation and / or that of the hooks 6,7 so as to coincide with any angular orientation of the isthmic regions with respect to the axis ZZ 'of the device and / or YY' of the line of the column vertebral that has to be corrected. Contrary to this, the sliding supports 15, 16 of the hooks, one called supralamy 5 on the upper part and the other called infralaminar 4 on the lower part, arranged along the vertical axis 77 'correspond to the fins 20 of the same vertebra 13, are constituted by at least 2 days that are cylindrical but not circular that slide and fit one inside the other, working together with a rail 17 of the central body l, preventing the rotation of said supports with respect to the ZZ 'axis, as shown in the appended figures: the support 15 of the hook 5 has for example a U-shaped cross section, on the inside of which the support 16 of the hook 4 of rectangular section can slide, holding all in a guide 17 of the internal section corresponding to the external figure, also rectangular of the support 15, in the single central block body 1. The assembly of such supports, four in number, according to this embodiment represented in the sliding guides inside said central body 1 where they are immobilized by any means passing through it, such as for example locking screws 10,11 screwed into the central body with their ends supported on said respective supports that are being used to lock. The common component or single central block body 1 includes, near the upper middle line - with respect to the hooks, at least one channel 14 in which any means of connection, such as a longitudinal metal rod can be received and locked , with another anchoring device 32 as shown in figure 2 by means of its unique means of fixing said device on said rods 2. Preferably, said connection means is constituted by two metal rods 2 and the means for fixing them on said central body on the two channels 14, is a collar 3 that sits on said rods and immobilizes them on the central body 1 holding them in the manner of clamps, this clamping being carried out by means of a nut 12 screwed on one of said means to immobilize the hook supports such as 1 of the locking screws The two longitudinal metal rods 2 are of a length adapted to the length of the spine which can be treated according to the desired assembly. An auxiliary system of instruments then makes it possible to separate or bring together the tetrapods or double clamps formed and thus fixed on two or more vertebrae in order to extend or shorten the vertebral curvature, allowing it to be clamped at 4 points such force Risk free. Temporary rods can be fixed on the isthmus rods that allow a derotation effect to be exerted on the vertebrae 13 and the two rods for axial medians, posterior 2, pre-curved according to the desired final shape of the spine, are used to block the tetrapods by means of their fixing clamp and immobilization, after a reduction of the deformation. The assembly can be accompanied by two bone grafts without any obligation to subsequently remove said system, but said dismantling is in any case easy to carry out by unscrewing the various locking systems 12,10,11 and dismantling the components of the device. Assemble that slideable guide one with respect to another and are therefore easy to remove. It should be noted that, in Figures 4 and 5, due to the morphology of the vertebrae, the axes ZZ 'of the so-called vertical or laminar hooks 4,5 and YY' of the connecting means 2, corresponding in effect to that of the ee of the vertebra 13, form an open angle upwards, ZZ 'moving away from YY' in the clockwise direction; while figures 1 and 2, the device is represented in effect with the upper part downwards the part that is normally above is directed downwards.