Pedicle engaging means.

DESCRIPTION

This invention relates to a pedicle adaptation device for use in spinal surgery.

Pedicle screws are well known devices that are used in systems for internal fixation of the spine. However, problems have arisen when trying to use pedicle screws in systems for segmental vertebral fixation. Some pedicle screws need wires to attach them to rods or other devices used for segmental vertebral fixation. An alternative, which is sometimes used, is the use of plates (instead of rods) or devices tailored to the circumstances. Pedicle screws can be used when there are no lamines present and when the consequent methods of using sub-laminal wires are not appropriate.

The present invention is intended to provide a device for adapting to the pedicle, particularly idiocy for use with existing devices for segmental vertebral fixation such as "Luque Rods" or, in a particular way, "Hartshill Rectangles" for further spinal surgery .

Following the present invention, the pedicle adaptation device comprises a bridge element that has a half arched portion, with an opening on each side of the arc, and a pair of limbs, generally coplanar, each with a hole for housing with rotation. a pedicle screw, and a pair of jaw elements, each of which has a coupling end with an opening in the arcuate part of the bridge element, and each having a fixing part with a hole for rotationally accommodating a pedicle screw; the orifice of a jaw element coincides with the orifice of the respective end of the bridge element, when the end of the jaw element is engaged in the respective opening in the arcuate part of the bridge element, and the part of the jaw element, between its limb and its fixing part, it was angled to form, with the union between the arched part and the respective limb of the bridge element, a pair of clamp parts to surround a rod or rod-like element of a vertebral fixation device.

It is anticipated at the moment that there are three occasions in which the pedicle adaptation device of the present invention can be used:

one. When an extensive laminectomy has previously been performed with the use of wire in the lumbar region.

two. When it is necessary to raise a number of levels and adapt intermediate levels, in particular to reduce slippage in spondylolisthesis.

3. In painful spondylolysis in young patients when, at present, with sublaminar wire the upper level has to be included to achieve fixation, while with the adaptation device to the pedometer of the invention, the internal fixation may be limited to a segment of movement.

The bridge element and the two jaw elements can be made of any biocompatible material but a flexible material, for example a stainless steel strip, allows surgeons to modify the shape of the arched part to vary the separation between the holes for the screw and / or alignment or angularity between the limbs containing the screw holes. However, more than one size of bridge element can be available, with arched parts of different spans and / or height. The width of the arcuate part can be reduced between the openings for coupling the ends of the jaw members, eg, the edges of the arcuate part can be concave in a plan view, to form a neck that has its smallest width in the middle part, to leave slack with respect to the adjacent spiny processes.

The holes in the parts of the ends of the bridge element and / or the holes in the fixing parts of the jaw elements can be elongated in the longitudinal direction of the bridge element, to allow adjustment of the separation and / or the inclination of the pedicle screws with respect to the general plane of the parts of the ends of the bridge element. The formation and elongation of the holes can be carried out by means of a ball mill applied to the distant faces of the parts of the bridge ends and the fixing parts of the jaw elements, respectively, and taken towards the arcuate part of the bridge element and in the opposite direction to the limbs of the jaw elements, respectively.

An embodiment of the invention is described below, and its use by way of example only, taking as reference the attached drawings, in which:

Figure 1 is a side view of the bridge element of the pedicle adaptation device following the invention.

Figure 2 is a plan view of the bridge element.

Figure 3 is an elevation view of the bridge element.

Figure 4 is a plan view illustrating a method for simultaneously forming two jaw elements.

Figure 5 is a side view of a jaw element after bending its limb.

Figure 6 is an elevation view taken from the far right of Figure 5.

Figure 7 corresponds to Figure 1, but shows the jaw elements coupled with the bridge element and the rods in place for fastening.

Figure 8 is a fragmentary sectional view, on a larger scale, taken through the part of the right end of the bridge element and the fixing part of the corresponding jaw element, and indicating how to lengthen the holes; Y

Figure 9 is a perspective view showing the assembly of the bridge element and the clamp elements attached to a "Hartshill rectangle" and secured by pedicle screws.

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In Figures 1 to 3, a bridge element for a pedicle adaptation device according to the invention has an arcuate middle part 11, with an opening 12 on each side of the arch, and a pair of extremities 13, generally coplanar, each with a hole 14 for rotationally accommodating a pedicle screw (see Figure 9).

Figure 4 illustrates the simultaneous formation of a pair of jaw elements 15, each with an end 16 attachable in an opening 12 of the arcuate part 11 of the bridge element 10 (see Figures 7 and 9) and each having a fixing part 17 with a hole 18 for rotationally accommodating a pedicle screw (see Figure 9 again).

Figures 7 and 9 show the ends 16 of the jaw elements 15 coupled in the openings 12 of the arcuate part 11 of the bridge element 10, the hole 18 of the fixing part 18 of each jaw element coinciding with the corresponding hole 14 at the respective end part of the bridge element, and part 19 of each jaw element 15, between its end 16 and its fixing part 17, was angled to form, with the junction 20 between the arcuate part 11 and the respective end part of the bridge element 10, a pair of clamp parts surrounding a rod or rod-like part 21 of a vertebral fixation device.

The ridges 22 of the arcuate part 11 are concave, in a plan view, to form a neck that has its smaller width in the middle part, to leave clearance with respect to the adjacent spiny processes 23 (see Figure 9).

The holes 14, 18, in the parts of the ends 13 of the bridge element 10 and the fixing parts 17 of the jaw elements 15, respectively, are formed and elongated by means of a ball mill applied to the distant faces 24, 25 , respectively, and carried towards the arcuate part 11 of the bridge element and in the opposite direction to the ends 16 of the jaw parts respectively (as indicated by the arrows in Figure 8).

Figure 9 shows a “Hartshill Rectangle” 26 held in place on the lower lumbar vertebra by means of sublaminar wires 27, at the joints between the long sides 21 'and the short folded joints 28 of the rectangle and the pedicle screws 29 - holding the assembly from the bridge element 10 and the jaw elements 15 to the rectangle and the spine, passing the screws 29 through the pedicle 30 and entering the body of the vertebra 31.

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