Intervertebral disc prosthesis with transversally arched, curved cylindrical articulation surfaces for the lumbar and cervical spine
First Claim
1. Intervertebral disc prosthesis for total replacement of an intervertebral disc within a lumbar and cervical spine, comprising articulating sliding partners, wherein an upper sliding partner firmly assembles to an upper vertebral body and a lower sliding partner firmly assembles to a lower vertebral body and an in-between the sliding partners located sliding area, wherein a) a first of such sliding partners is constructed in such a manner, that a side opposite of a side for assembly with a vertebral body has a convex curvation (convex articulation area, convexity), and a geometry of the convexity is defined it correlating to a segment of a cylinder along its longitudinal axis from right to left lateral with a transversal ventrally directed arched curvation, wherein the convexity is surrounded dorsally, ventrally and laterally at both sides by an edge, and b) a second of such sliding partners is constructed in such a manner, that the opposite side of the side for the assembly with a vertebral body has a concave articulation area (concavity) and a geometry of the concavity is defined by having a recess corresponding to the convexity of the first sliding partner, and the concavity is surrounded dorsally, ventrally and to both lateral sides by an edge, and c) the edges of both sliding partners have an outwardly opening angle (aperture angle) towards each other, wherein a. no inclination of the sliding partners towards each other in lateral direction being possible, and b. the maximal possible motion of the sliding partners in dorsoventral direction is limited by a gap-closure of the edges of the two sliding partners, and d) the rotation of the sliding partners towards each other is limited by the tolerance between convexity and concavity right and left laterally of the transversally curved cylindrical articulation areas.
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Abstract
The invention relates to an intervertebral disc prosthesis for the total replacement of a natural intervertebral disc within the lumbar and cervical spine, comprising articulating sliding partners, where the upper sliding partner has means for a firm assembly to an upper vertebral body and the lower sliding partner has means for a firm assembly to a lower vertebral body and at least one sliding surface that is between two sliding partners. According to the invention, functional two- and three part designs are planned and both prostheses have in common, that only a dorsoventral- and rotation movement is possible as a result of laterolaterally aimed, transversally arched, ventrally curved cylindrical convexity(ies) and corresponding concavity(ies), however without an inclination of the sliding partners in a lateral direction. In a further design, the cylindrical articulation surfaces are un-curved, enabling a motion of the sliding partners in only a ventrodorsal direction. According to the invention, the intervertebral disc prostheses are suited for an implantation from lateral and ventrolateral, particularly in revision surgeries.
150 Citations
38 Claims
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1. Intervertebral disc prosthesis for total replacement of an intervertebral disc within a lumbar and cervical spine, comprising
articulating sliding partners, wherein an upper sliding partner firmly assembles to an upper vertebral body and a lower sliding partner firmly assembles to a lower vertebral body and an in-between the sliding partners located sliding area, wherein a) a first of such sliding partners is constructed in such a manner, that a side opposite of a side for assembly with a vertebral body has a convex curvation (convex articulation area, convexity), and a geometry of the convexity is defined it correlating to a segment of a cylinder along its longitudinal axis from right to left lateral with a transversal ventrally directed arched curvation, wherein the convexity is surrounded dorsally, ventrally and laterally at both sides by an edge, and b) a second of such sliding partners is constructed in such a manner, that the opposite side of the side for the assembly with a vertebral body has a concave articulation area (concavity) and a geometry of the concavity is defined by having a recess corresponding to the convexity of the first sliding partner, and the concavity is surrounded dorsally, ventrally and to both lateral sides by an edge, and c) the edges of both sliding partners have an outwardly opening angle (aperture angle) towards each other, wherein a. no inclination of the sliding partners towards each other in lateral direction being possible, and b. the maximal possible motion of the sliding partners in dorsoventral direction is limited by a gap-closure of the edges of the two sliding partners, and d) the rotation of the sliding partners towards each other is limited by the tolerance between convexity and concavity right and left laterally of the transversally curved cylindrical articulation areas.
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2. Intervertebral disc prosthesis for total replacement of an intervertebral disc within a lumbar and cervical spine, comprising
articulating sliding partners, wherein an upper sliding partner firmly assembles to an upper vertebral body and a lower sliding partner firmly assembles to a lower vertebral body and wherein between the upper and lower sliding partner a further, middle sliding partner is located, corresponding in such a way to the inner surfaces of the upper and lower sliding partner that an upper and a lower sliding area is formed, wherein a) the middle sliding partner has on the upper and lower surfaces a convex curvation (convex articulation area, convexity), and a geometry of the convexities is defined by them correlating to a segment of a cylinder along its longitudinal axis from right to left lateral with a transversal ventrally directed arched curvation, and b) upper and lower sliding partner have an concave inner articulation area (concavity), and a geometry of the concavities being defined by a corresponding recess to the articulating convexity of the middle sliding partner, and the concavities of the upper and lower sliding partners being surrounded dorsally, ventrally and laterally at both sides by an edge, and c) the edges of the articulation sliding partners having an outwardly opening angle (aperture angle) towards each other, wherein a. no inclination of the sliding partners towards each other in lateral direction is possible, and b. the maximal possible motion of the sliding partners in dorsoventral direction is limited by a gap-closure of the edges of the sliding partners, and d) the rotation of the sliding partners towards each other is limited by the tolerance between the convexities and concavities right and left laterally of the transversally curved cylindrical articulation areas.
Specification