Patent ID: 8066751
Filing Date: 2011-11-29
Classification: A61B

Abstract:
1. An orthopaedic device, in particular implantable in the cervical spine of a patient, said orthopaedic device comprising, on the one hand, a support structure of a plate type, which is delimited by a top face and by a bottom face, and which is provided with at least one through-orifice having a height and an internal surface, and on the other hand, of at least one screw having a screw head and a screw body, said through-orifice being shaped so as to enable passage of said screw, the contact between said screw head and said plate being made through complementary spherical surfaces, said orthopaedic device also comprising added locking means, able to prevent or at least to limit said screw from moving back once its head is suitably in rest on said plate, said locking means comprising an annular groove, formed in a portion of the height of the internal surface of said orifice, delimited by an upper annular flange, a lower annular flange and a bottom, in which groove is added a slotted metal ring, with an internal edge and an external edge, having a radial elastic deformation ability and of which, at rest, on the one hand, the internal edge has a diameter smaller than that of said orifice, on the other hand, the external edge has a diameter smaller than that of the bottom of said annular groove, said screw head comprising an annular protuberance diverging from said screw body to an annular channel , said protuberance being shaped so as to enable, when said head moves forward within said associated orifice, radial expansion of said ring within its receiving groove, and then, in the final phase of screwing, accommodation of said ring within said annular channel, by elastic radial shrinkage, so as to form said backstop locking means, wherein: a—the orifice of the support plate is delimited by successively, from the top face of said plate to the bottom face of the latter: b—said screw head comprises successively, from a free end thereof to said screw body c—the spring ring has a thickness smaller than the thickness of said groove in which it is accommodated, to be provided with at least one axial degree of freedom within said groove.