Transverse spinal connection device

TRANSVERSE SPINAL LINK DEVICE

The present invention relates to a transverse spinal connection device which can be used in neurosurgery, orthopedic surgery and more generally in spinal surgery and intended to constitute a bracing connection, in particular between two spinal osteosynthesis rods.

These rods, which are longitudinal rods of circular section, are intended to adapt to the physiological curvatures of the spine or to restore these curvatures and must most of the time, after installation using pedicle screws or any other posterior fixation system, and in order to allow good reduction and good retention, be connected together in one or more places using transverse bars.

Devices of the bar type secured to the intersection with the retention rods by means of connecting and locking members have drawbacks. Some use as connecting / locking members kinds of collars which must first be threaded onto the retention rods before the latter are secured with the pedicle screws or the like.

This does not facilitate the establishment of the rods and, moreover, once the rods have been fixed, the transverse bar (s) cannot be changed place because the connecting / locking collars are trapped in the rods. Other devices of the same type include connecting / blocking members no longer threaded onto the retention rods but attached to the latter, once in place, these members being made up of two parts which surround the rod.

If this system is more practical and flexible than the previous one, because it allows the installation of a transverse connecting bar in various places of the restraining rods after their fixing and a possible change of place, it is not however completely satisfactory.

Indeed, although the two parts of said connecting / blocking members can be attached to the retention rods in situ, they however completely surround the rods and, therefore, require local intervention on the vertebrae to release the necessary space. to receive said parts, which furthermore limits the possibilities of implantation of the transverse bars.

The object of the present invention is precisely to overcome these drawbacks by proposing a transverse connection system which can be adapted directly in particular to spinal osteosynthesis rods in situ, without prior intervention to free up the necessary space and allowing the installation of the transverse bars truly in place. anywhere on the retention rods, apart from the pedicle screws of course.

To this end, the invention relates to a transverse spinal connection device, of the type comprising a transverse bar which can be secured to at least one spinal osteosynthesis rod by means of a connecting / blocking member between said transverse bar. and said osteosynthesis rod, capable of being attached to the latter in situ, characterized in that said connecting / blocking member consists of:

- a first jaw-shaped piece, provided with a passage for the transverse bar and a locking screw or the like capable of projecting into said passage,

- and a second piece in the form of an opposing jaw articulated on the first piece,

- The bar in place in the passage being capable, when tightening said screw, to come to bear both against the first part and against the second part and to bring said jaws closer together.

According to a preferred embodiment, the jaws are configured so as not to completely surround the osteosynthesis rod, the passage formed in the first part extends substantially orthogonally to the axis of the osteosynthesis rod in position between the jaws, the screw is disposed on the other side of the jaws with respect to the transverse bar and the second part is articulated on the first by a fork through which said transverse bar passes.

The shape and dimensions of the passage of the transverse bar in the first part are determined so as to allow said bar a multidirectional movement in order, on the one hand, to allow the jaws to move apart sufficiently to overlap and grip the rod d. 'osteosynthesis and, on the other hand, optionally to give the transverse bar a certain angulation relative to the osteosynthesis rod to take account of the implantation conditions.

Such a device is put in place almost instantly, for example to brace two osteosynthesis rods in place, by simply engaging the device over each of the rods of the jaws, in the open position, at the desired locations, then, once the jaws are in position. , screwing of the screw which puts pressure on the transverse bar and on the second part / jaw, which approaches the first by tightening the osteosynthesis rod. At the end of screwing, not only the osteosynthesis rod but also the transverse bar are firmly blocked relative to the device.

A firm and secure mutual blocking is thus obtained between the osteosynthesis rod and the transverse bar.

Unlocking the device, for example for possible movement along the osteosynthesis rods, is just as easy and quick.

The manipulation of this device is carried out essentially from top to bottom, the patient lying down, without having to carry out any surgical gesture either laterally with respect to the rod (aviva articular), neither medially, nor even over the rod of. osteosynthesis.

Indeed, the tapered end profile of the jaws and the fact that the latter leave the periphery of the osteosynthesis rod facing the spine free, for example over an extent of the order of one third of said periphery, allows the positioning of said jaws without problem, that is to say without having to clear a space for this purpose using an instrument.

Other characteristics and advantages will emerge from the following description of an embodiment of the device of the invention, description given by way of example only and with reference to the appended drawings in which:

- Figure 1 is a schematic view of a spinal osteosynthesis provided with a transverse connection device according to the invention;

- Figure 2 is a perspective view of a preferred embodiment of the device of the invention;

- Figures 3a to 3c respectively show a side elevational view, a right view and a top view of a first part of the device;

- Figures 4a to 4c respectively show a side elevational view, a right view and a top view of a second part of the device, and

- Figure 5 is a sectional view along the axis of the transverse bar of the device formed of the parts of Figures 3a to 3c and 4a to 4c, mounted and in the position of use.

In Figure 1, there is schematically shown lumbar vertebrae 1 on which two spinal osteosynthesis rods 2 are implanted, in the known manner using pedicle screws symbolized at 3.

The two rods 2 are braced by a device according to the invention comprising a transverse bar 4 secured to the rods 2 at the crossing points by connecting / blocking members shown diagrammatically at 5.

FIG. 2 illustrates a preferred embodiment of the device of the invention, which consists, on the one hand, of a transverse connecting bar 4 of rectangular section and, on the other hand, of a connecting member / blocking 5 between the bar 4 and a cylindrical rod 2 for spinal osteosynthesis comprising a first part 6 forming a first jaw and a second part 7 articulated on the part and forming an opposing jaw, the two jaws enclosing the osteosynthesis rod 2.

Figures 3a to 3c and 4a to 4c show parts 6 and 7 according to Figure 2.

The first part 6 represented by FIGS. 3a to 3c comprises a tapered end forming a jaw 8 with a cylindrical active face. The jaw 8 is extended by a central part 9 crossed by a passage 10 of rectangular section with an axis substantially orthogonal to the axis of the cylinder defining the active face of the jaw 8.

Finally, the central part 9 is itself extended by an end opposite to the jaw 8 and in the form of a rectangular table 11 in which a threaded hole 12 is drilled opening into said passage 10.

The passage 10 has an inlet section which goes, with regard to the height and considering FIG. 3a, by increasing from right to the left so that the floor 13 of said passage 10 has a high point (ridge 14) at the entrance and a low point 15 at its other end.

On the opposite sides of the part 6, at the height of the central part 9, two journals 16 are provided on which the part 7 is articulated.

Finally, on one of said flanks is also provided at the height of the table 11 a removable pin 17 for retaining the part 7 mounted on the part 6, as will be seen below.

The second part 7 shown in Figures 4a to 4c is shaped as a jaw 18 opposing the jaw 8, the two jaws being substantially symmetrical.

The jaw 18 is extended by a fork with two branches 19, the ends of which are curved at 20 so as to articulate on the journals 16 of the part 6. Between the branches 19 extends a face 21 of the jaw 18 which corresponds on the floor 13 of room 6. The parts 6, 7 are mounted and articulate as shown in Figure 2, the pin 17 being inserted into the part 6 after placing the part 7 on the part 6. One of the branches 19 of the part 7 is thus held captive between the pin 17 and one of the journals 16, the part 7 having a certain angular displacement to open the pair of jaws 8-18 sufficiently for the passage between them of the rod 2 to be blocked.

Figure 5 shows in section the parts 6 and 7 of Figures 3a to 3c and 4a to 4c, assembled and mutually blocking the rod 2 and the bar 4.

The device's instructions for use are as follows:

The two parts 6, 7 being assembled and locked by the pin 17, the bar 4 is introduced into the passage 10 and between the branches 19 of the fork, a screw 22, for example without a head and with a recessed hexagonal recess, being inserted in the threaded hole 12 without protruding into the passage 10 so as not to interfere with the engagement of the crossbar 4.

At the place of the rod 2 in place where it is desired to block the bar 4, the jaws 8, 18 are presented against the rod 2. The pressure exerted opens the jaws which then surround the rod 2. It Then just screw the screw 22. The latter protrudes into the passage 10, bears against the face facing the bar 4 which itself rocks around an axis parallel to the hinge axis (pins 16) parts 6, 7, resting on the entry edge 14.

By tilting the bar 4 presses the part 7 between the branches 19 and causes it to pivot so as to bring the jaw 18 closer to the jaw 8, thus wedging the rod 2.

At the end of screwing, the rod 2 is firmly blocked between the jaws 8, 18 and the bar 4 is firmly blocked between the screw 22 and the part 7.

The height of the passage 10 is notably greater than the thickness of the bar 4 to allow the part 7 to move away from the part 6 sufficiently for the free passage of the rod 2 between the jaws 8, 18. The width of the passage 10 is also slightly greater than that of the bar 4 to allow a certain angular adaptation between the rod 2 and the bar 4. Thus, as illustrated in FIG. 1, the two osteosynthesis rods 2 are deliberately arranged while not being parallel so that the transverse bar 4 does not form a right angle with the rods 2.

The device of the invention allows such an assembly, the parts 6, 7 remaining aligned with the rods 2, but the bar 4 being able to pivot laterally slightly with respect to these parts. This avoids having to bend the bar 4 to have a truly right-angled crossing with the rods 2.

Unlocking and removing the device is just as quick and easy since it suffices to unscrew screw 22 and pull on bar 4 or parts 6, 7 to remove jaws 8, 18.

As can be seen in FIG. 5, a substantial part (almost a third in the drawing) of the periphery of the rod 2, on the spine side, is released. This, together with the fact that the shape of the jaws 8, 18 is tapered, allows placement on the rods 2 at any location without having to free up the necessary space (jointing joints) in the immediate vicinity of the rods. Thus, even if the rod 2 is in contact, on its face facing the patient, with a bone tissue, the device of the invention will nevertheless be capable of being put in place directly and without preparation.

It should be noted that the assembled parts 6, 7 could be placed on the rod 2 before insertion of the bar 4 in the passage 10.

It should also be noted that the possibilities of opening the jaws 8, 18 allow the device to adapt to different diameters of osteosynthesis rods (for example 4, 5 or 6 mm).

The rod 2 and the bar 4, the parts 6, 7 and the screw 22 are made of material approved for surgical implantation, for example titanium.

The transverse connecting bar 4 has for example a rectangular section of 3 mm by 4 mm with rounded edges. The shapes and dimensions of the bar 4 and of the passage 10 of the part 6 can of course vary, the bar 4 being able in particular to be square or cylindrical.

Grooves can be formed on the part of the bar 4 capable of coming into contact with the screw 22.

Finally, the invention is obviously not limited to the embodiment described and shown but on the contrary covers all the variants thereof, in particular as regards the shapes and dimensions of the jaws 8, 18, the mode and the means of articulation. parts 6, 7 between them, or else the means exerting pressure on the bar 4 and part 7 to jointly ensure the locking relative to the part 6 of the rod 2 and of the bar 4.