Transforaminal intersomatic cage and an instrument for implanting the cage

Abstract

This present invention concerns a transforaminal intersomatic cage for an intervertebral fusion graft, and an instrument and method for implanting the cage, an embodiment of the cage having a body in the shape of a circular arc and comprising a lateral concave surface, a lateral convex surface, a straight upper surface, a straight lower surface and an end wall having at least one hole, called the end hole, designed to receive a rod of an instrument for implanting the cage between the vertebrae, wherein: the end hole has an orientation that is more or less tangential to the circular arc described by the body; the extremity opposite to the end wall of the body includes a return part extending the body toward the centre of the circle on which the circular arc described by the body lies.

Description

[0001] cross reference [0002] This application claims French Patent Application No. FR0601315 filed in France on February 15, 2006, which is hereby incorporated by reference for all purposes. technical field [0003] The present invention relates to the field of intervertebral arthrodeses (fusion of two vertebrae) and, more particularly, to implantation between two adjacent vertebrae to allow bone tissue grafts to be inserted into the disc space and in the Intersomatic cages growing in the intervertebral disc space. In fact, after insertion or implantation of an intervertebral cage, the intervertebral space is filled with autologous spongy bone or a suitable bone substitute. The invention also relates to an instrument for implanting an intervertebral cage between vertebrae, in particular through a transforaminal approach. An intervertebral cage designed to be placed between two vertebrae to restore and / or maintain disc space through disc replacement, and a graft of bone ti...

AI Technical Summary

Problems solved by technology

These interbody cages have the following disadvantages: firstly, a relatively large incision is required in the annulus (outside of the intervertebral disc), and secondly, since the graft is restricted to the center of the cage before arthrodesis can be achieved within the chamber at which the transforaminal approach extends, and thus require a relatively long time, and third, be of such a size that it cannot be performed without partial or total resection of the articular processes disposed behind the hole through which the transforaminal approach extends. Transforaminal approach for grafting

This intervertebral cage has a defect in the bone tissue and can therefore cause disease if not adequately sterilized as previously stated

This intervertebral cage also has the disadvantage of being ultimately not strong enough to reliably withstand the stresses applied to it when implanted in the intervertebral disc space

Moreover, this cage has the disadvantage of having a hole oriented towards the center of the cage, in particular towards the center of the concave surface, with the result that the cage is even more fragile

Some instruments known from the prior art are of sufficiently small size not to require facet resection, and some have angled portions that allow the instrument to bypass structures blocking access to the intervertebral disc space, but are designed for fixation of the intervertebral disc space. The rod of the cage and the hole of the intervertebral cage into which the rod is inserted are not very compatible with the optimal thrust axis that would allow the cage to be inserted between the vertebrae and the rod is prone to failure when the cage has been implanted. Withdraw in not very compatible directions

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